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Digital Projector

Digital projector

A digital projector is an electro-optical machine which converts image data from a computer or video source to a bright image which is then imaged on a distant wall or screen using a lens system. The projector serves the following purposes:
- Visualization of data stored in a computer for presentations
- Demonstration of program products for a large number of prospective customers
- The projector replaces the white board as well as written documents with the Interactive whiteboard.
- Watching moving images from a video tape player or digital video disk player. Digital projectors may also be built into cabinets which use a rear projection screen to form a single unified display device, now popular for "home theater" applications. A typical resolution for a portable projector will be the SVGA standard (800×600 pixels), with more expensive devices supporting XGA (1024×768 pixels). The cost of a device is not only determined by its resolution, but also by its brightness. For use in large conference rooms the brightness should be between 1,000 and 4,000 ANSI lumens. Digital projection technologies:
- high intensity CRT
- LCD projectors using LCD light gates
- Texas Instruments' DLP technology Obsolete electronic projection technologies:
- Eidophor oil-film projectors The current dominant technology at the high end for portable digital projectors is Texas Instruments' DLP technology, with LCD projectors dominating the low end. High intensity CRT devices are suitable only for fixed instalations.

Producers of projectors

- Acer
- ASK
- BenQ
- Barco
- Canon
- Dell
- Digital Projection International
- Epson
- Hewlett-Packard
- Hitachi
- IBM
- InFocus
- LG
- Mitsubishi Electric
- NEC
- Optoma
- Panasonic
- Philips
- Runco
- SIM2 Multimedia
- Sony
- ViewSonic

External links

- [http://www.theprojectorpros.com/learn.php?s=learn&p=theater_dlp_vs_lcd_vs_lcos Projectors] DLP™ vs. LCD vs. LCOS Projectors (theprojectorpros.com)
- [http://www.theprojectorpros.com/business.php?s=business&p=buyers_guide Business Projectors] A Buyers' Guide - The Most Common Questions (theprojectorpros.com)
- [http://www.thehometheaterpros.com/theater.php?s=theater&p=compare Compare Home Theater Projectors] Compare features of 3 projectors at a time (thehometheaterpros.com) Category:Office equipment Category:Display technology ja:プロジェクタ

Projection screen

Projection screens are installations consisting of blank surface and a support structure used for projecting an image for the view of an audience. Projection screens may be permanently installed as in a movie theater, painted on the wall[http://specialsections.nypost.com/news/nypost/nyphome/20050521/p44.asp], semi-permanent or mobile, as in a conference room or other non-dedicated viewing space. Uniformly white or grey screens are used almost exclusively as to avoid any discoloration to the image, while the most desired brightness of the screen depends on a number of variables, such as the ambient light level and the luminous power of the image source. Flat or curved screens may be used depending on the optics used to project the image and the desired geometrical accuracy of the image production, flat screens being the more common of the two. Screens can be further designed for front or back projection, the more common front projection systems having the image source situated on the same side of the screen as the audience. Different markets exist for screens targeted for use with digital projectors, movie projectors and slide projectors, although the basic idea for each of them is very much the same: front projection screens work on diffusely reflecting the light projected on to them, whereas back projection screens work by diffusely transmitting the light through them.

Screens by installation type

Permanently installed screens can often be found in venues that are used for continuous visual presentations, such as movie theaters. These can be pre-assembled or assembled on the spot. Pull-down screens are a often used in multipurpose spaces where permanently installed screen would require too much space. These commonly use painted fabric that is rolled in the screen case when not used, making them somewhat more prone to damage than rigid screens. Rigid wall-mounted screens maintain their geometry perfectly, which makes them suitable for applications that demand exact reproduction of image geometry, and a good choice for presentation where aesthetics are important. Mobile screens usually use a pull-down screen on a free stand. These can be used when it is impossible or impractical to mount the screen to a wall or a ceiling, but the fabric of the screen can rarely stay immobile, giving imperfections to the projected image.

Home theater screens and gain

One of the most often quoted properties in a home theater screen is the gain. This is a measure of reflectivity of light compared to a screen coated with titanium dioxide, when the measurement is taken for light targeted and reflected perpendicular to the screen. Titanium oxide is a bright white colour, but greater gains can be accomplished with materials that reflect more of the light parallel to projection axis and less off-axis. Frequently quoted gain levels of various materials range from 0.8 of light grey matte screens to 2.5 of the more highly reflective glass bead screens, some manufacturers claiming even higher numbers for their products. Very high gain levels could be attained simply by using a mirror surface, although the audience would then just see a reflection of the projector, defeating the purpose of using a screen. Screens with higher gain will exhibit more mirror-like properties, namely a bright "hot spot" in the screen, an enlarged (and greatly blurred) reflection of the projectors lens. Opinions differ as to when this "hot spotting" begins to be distracting, but most viewers have trouble to notice as large as 30% difference in the image luminosity, unless presented with a test image and asked to look for variations in brightness. In normal screens the greatest intensity of light will reflect at an equal and opposite angle to the angle of incidence, favouring ceiling-mounted projector setups as it will maximize the apparent screen brightness on the audience level. Glass-bead screens exhibit a phenomenon of retroreflection, where the highest intensity of the light is reflected back to where it came from. This is intended for setups where the image source is placed in the same direction from the screen as the audience. Users frequently report some hotspotting in such screens, although this type of screen is seen as desirable due to the high image intensity they can produce.

Screen geometry and optics

Square-shaped screens used for overhead projectors sometimes double as projection screens for digital projectors in meeting rooms, where space is scarce and multiple screens can seem redundant. These screens have an aspect ratio of 1:1 by definition. Other popular aspect ratios include 4:3 and a widescreen ratio of 16:9, which are often used as dedicated data projection and home cinema use, respectively. Most image sources are designed to project a perfectly rectangular image on a flat screen. Optics designed for a curved screen will result in a pincushion effect when an image is projected on a flat screen.

Image brightness and contrast

Apparent contrast in a projected image - the range of brightness - is dependent on the ambient light conditions, luminous power of the projector and the size of the image being projected. A greater image will lead to less luminance (luminous power per unit solid angle per unit area) and thus a smaller contrast in the presense of ambient light. Some light will always be created in the room when an image is projected, increasing the ambient light level and thus contributing to the degradation of picture quality. This effect can be lessened by decorating the room with dark colours. The real-room situation is different from the contrast ratios advertised by manufacturers, who record the light levels with projector on full black / full white, giving as high contrast ratios as possible. Manufacturers of home theater screens have attempted to resolve the issue of ambient light by introducing screen surfaces that direct more of the light back to the light source. The rationale behind this approach relies on having the image source placed near the audience, so that the audience will actually see the increased reflected light level on the screen. The level of omnidirectional light will be, in theory, unaffected by the reflective properties of the screen, whether highly directional or diffuse. Highly reflective screens tend to suffer from hot spots, when part of the screen seems much more bright than the rest: this is a result of the high directionality (mirror-likeness) of such screens. Screens with high gain also have a narrower usable viewing angle, as the amount of reflected light rapidly decreases as the viewer moves away from front of such screen. A relatively recent attempt in improving the perceived image quality is the introduction of grey screens, which are more capable of darker tones in the presence of ambient light than their white counterparts. It can be disputed whether such screens increase the actual contrast ratio possible in the image, as a grey surface will necessarily reflect less light from the projected image, as well. Grey screens are designed to rely on powerful image sources that are able to produce adequate levels of luminosity so that the white areas of the image still appear as white, taking advantage of the non-linear perception of brightness in the human eye. At least one screen is designed to selectively reflect the narrow wavelengths of projector light while absorbing other wavelengths in the optical spectrum. This screen made by Sony [http://www.cdfreaks.com/news2.php?ID=9984] appears to be black when viewed in normal room light, and it is designed to be relatively unaffected by ambient light while still being capable of producing intense colors. It is unclear whether this approach protects the image from being degraded due to light that reflects from the screen to the room and back. More reading: [http://www.projectorcentral.com/projector_screens_gain.htm] - Projectorcentral.com - Screen gain, reflectiveness [http://entertainment.howstuffworks.com/movie-screen.htm] - Howstuffworks.com - How movie screens work [http://gothifi.com/hifishowroom/screentutor.htm] - Hifishowroom - on different screen types by gain and viewing angle

Interactive whiteboard

. An Interactive Whiteboard is a dry-erase whiteboard writing surface which can capture writing electronically. Interactive whiteboards require a computer. Some interactive whiteboards also allow interaction with a projected computer image. They are most commonly used in the office or classroom. Interactive whiteboards are used in one of two ways: # To capture notes written on the whiteboard surface using dry-erase ink or # To control (click and drag) and/or mark-up (annotate) a computer-generated image projected on the whiteboard surface from a digital projector.

How it works

The interactive whiteboard connects to a computer with a USB or serial port cable. Some whiteboards draw power from the computer. Usually, device driver software is loaded into the attached computer. The whiteboard driver automatically starts when the computer is turned on, and the interactive whiteboard becomes active once the driver is running. A digital projector can be connected to your computer and focused on the whiteboard surface to project a computer image. In most cases, it is necessary to tell the interactive whiteboard where the projected image is located on the whiteboard by touching one or more locations on the whiteboard surface with the stylus. This process is called alignment or calibration. A few newer interactive whiteboards can automatically detect projected images and do not require this step. The driver converts contact with the interactive whiteboard into mouse clicks or digital ink. There are a variety of technologies used in interactive whiteboards:
- Touch-Sensitive - Two electrically conductive sheets are separated by a small gap of air. When they touch, electical contact is made. The resistance or capacitance changes in the sheets establishes the (X,Y) location of the touch. This technology has a soft writing surface and allows one to use a finger, a dry-erase marker, or a stylus on the whiteboard.
- Electromagnetic - An array of wires behind the board interacts with a coil in the stylus tip to determine the (X,Y) coordinate of the stylus. Styli are either active (require a battery or wire back to the whiteboard) or passive (alter electrical signals produced by the board, but contain no power source). This technology usually has a hard writing surface, but requires a special stylus or dry-erase marker holder and touch cannot be used.
- Laser - An infrared laser is located in each upper corner of the whiteboard. The laser beam sweeps across the whiteboard surface (much like a lighthouse sweeps light across the ocean) by using a rotating mirror. Refelctors on the stylus or marker reflect the laser beam back to the source and the (X,Y) position can be triangulated. This technology has a hard (usually ceramic on steel) surface, which has the longest life and erases most cleanly. Markers and styli are passive, but must have refelctive tape to work. Touch cannot be used.
- Ultrasonic and Infrared - When pressed to the whiteboard surface, the marker or stylus sends out both an ultrasonic sound and an infrared light. Two ultrasonic microphones listen for the sound and measure the difference in the sound's arrival time, providing enough information to triangulate the location of the marker or stylus. This technology allows whiteboards to be made of any material, but requires an active dry-erase marker or stylus. Touch cannot be used.

Classroom Uses

Interactive whiteboards are used in many schools as replacements for traditional whiteboards and to provide ways to show students material on the computer (educational software, web sites, etc.). Projectors, which are used on interactive whiteboards, can also be connected to a video recorder or DVD player eliminating the need for a television in the classroom. The interactive whiteboard also allows students to come up and solve puzzles and math problems, demonstrate their knowledge in a particular subject, and allows the teacher to keep notes on the lesson The interactive whiteboard is more commonly called a SmartBoard in education.

Literature Reviews

There are a number of recent literature reviews and papers on the use of interactive whiteboards in the classroom: Beauchamp, G and parkinson, J (2005) Beyond the wow factor: developing interactivity with the interactive whiteboard. School Science Review (86) 316: 97-103. Glover, D and Miller, D, Averis, D and Door, V. (2005) The interactive whiteboard: a literature survery. Technology, Pedagogy and Education (14) 2: 155-170. Smith, H.J. , Higgins, S., Wall, K., and Miller, J. (2005) Interactive whiteboards: boon or bandwagon? A critical review of the literature, Journal of Computer Assisted Learning, 21(2),pp.91- 101.

Office Uses

Interactive whiteboards are used in office environments to capture meeting notes and to work on collaborative projects. They are particularly useful with interactive applications, such as presentation software (e.g. PowerPoint), Computer-aided design (CAD) packages, etc.

Accessories

A variety of accessories are available for interactive whiteboards:
- Projector - Allows control of a computer from the whiteboard
- Track - Allows the whiteboard to be placed over a traditional whiteboard, tackboard, etc. to provide additional wall space at the front of the room. Some tracks provide power and data to the whiteboard as well.
- Mobile stand - Allows the interacive whiteboard to move between rooms. Many are height adjustable as well.
- Printer - Allows copies of the whiteboard notes to be made.
- Slate or tablet - Allows students control of the whiteboard away from the front of the room.
- Voting system - Allows students to answer test questions posted on the whiteboard.
- Wireless unit - Allows the interactive whiteboard to operate without wires to the computer.
- Remote control - Allows the presenter to control the board from different parts of the room, and eliminates on-screen toolbars.

Manufacturers

- [http://www.egan.com Egan Visual] - Touch-Sensitive
- [http://www.e-beam.com Luidia] - Ultrasonic and Infrared
- [http://www.numonics.com Numonics] - Electromagnetic
- [http://www.polyvision.com PolyVision Corpoation (Steelcase)] - Touch-Sensitive, Electromagnetic, Laser, Ultrasonic and Infrared
- [http://www.prometheanworld.com/home.html Promethean Interactive Whiteboards and Collaborative Classroom Systems] - Electromagnetic
- [http://www.smarttech.com Smart Technologies, Inc.] - Touch-Sensitive
- [http://www.mimio.com Virtual Ink] - Ultrasonic and Infrared

External Links

- [http://www.projectors.com Best Buy Projectors] Category:Office equipment

XGA

XGA, the Extended Graphics Array is an IBM display standard introduced in 1990. Today, it is best known as a synonym for the 1024×768 display resolution, but the official definition is broader than that. It was not a new and improved replacement for Super VGA, but rather became one particular subset of the broad range of capabilities covered under the "Super VGA" umbrella. The initial version of XGA expanded upon IBM's VGA (Video Graphics Array), adding support for two resolutions:
- 800×600 pixels with high colour (16 bits per pixel, i.e. 65,536 colors).
- 1024×768 with a palette of 256 colours (8 bits per pixel) Like its predecessor (the IBM 8514), XGA offered fixed function hardware acceleration to offload processing of 2D drawing tasks. XGA and 8514 could offload line-draw, bitmap-copy (bitblt), and color-fill operations from the host CPU. XGA's acceleration was faster than 8514's, and more comprehensive in that it supported more drawing primitives and XGA's 16 bits per pixel (65,536 color) display-mode. XGA-2 added true-color mode for 640×480, 1024×768 support for high colour and higher refresh rates, and improved accelerator performance. All XGA modes have a 4:3 aspect ratio rounded to 8 pixels. XGA should not be confused with VESA's EVGA (Extended Video Graphics Array) that was released at a similar time.

Clone hardware

XGA hardware was not cloned as extensively as VGA hardware. Nevertheless, at least one graphics company made several XGA-compatible chips, the IIT AGX.

Reference

Category:Computer graphics ja:Extended Graphics Array

ANSI

The American National Standards Institute (ANSI) is a private, non-profit standards organization that serves as a facilitator for the standardization work of its members in the United States. ANSI accredits standards developing organizations (SDOs) that meet a set of requirements and criteria governing the management of consensus standards development. Accredited SDOs can submit candidate documents to ANSI for consideration and approval as American National Standards (ANS). ANSI's goal is to promote and facilitate voluntary consensus standards and conformity assessment systems and maintain their integrity. It is the U.S. member body to the ISO and the IEC, via the U.S. National Committee (USNC). In 1916 the American Institute of Electrical Engineers (now IEEE) invited the American Society of Mechanical Engineers (ASME), American Society of Civil Engineers (ASCE), American Institute of Mining and Metallurgical Engineers (AIMME) and the American Society for Testing Materials (ASTM) to aid them and establish a national body to develop standards and help other standard developing agencies. Two years later, in October 1918, ANSI, originally founded as the American Engineering Standards Committee (AESC), was formed to serve as the national coordinator in the development of standards and as an impartial organization to approve national consensus standards. A year after AESC was founded it approved its first standard on pipe threads. In 1920, they undertook the first major project coordinating national safety codes. The first American Standard Safety Code was approved in 1921 and covered the protection of heads and eyes of industrial workers. As the organization grew, it became apparent that AESC had outgrown its structure, and in 1928 was reorganized and renamed the American Standards Association (ASA). In 1946, ASA formed the International Organization for Standardization by joining with standards bodies of 25 other countries. In 1966 it was reorganised as the United States of America Standards Institute. In 1969 it changed its name to American National Standards Institute. In its first ten years, AESC also approved national standards in the fields of mining, electrical and mechanical engineering, construction and highway traffic. The ASA photographic exposure system became the basis for the ISO film speed system, currently used worldwide. In Microsoft Windows, the phrase "ANSI" refers to the Windows ANSI code pages. Most of these are fixed width though there are some variable width ones for ideographic languages. Some of these are very close to the ISO-8859 series leading many to falsely assume that they are identical. ASCII art which is colorized or animated by way of ANSI terminal control codes (X3.64 sequences) are commonly referred to as "ANSI art" and were predominantly popular on bulletin board systems throughout the 1980s and 1990s.

External links

- [http://www.ansi.org/ American National Standards Institute] official website
- About ANSI Overview, from ANSI web site, as of March 2, 2003; [http://www.ansi.org/about_ansi/overview/overview.aspx?menuid=1]
- ANSI - an Historical Overview, from ANSI web site, as of March 2, 2003; [http://www.ansi.org/about_ansi/introduction/history.aspx?menuid=1]
- [http://www.paulschou.com/tools/xlate/ Online Char (ASCII), HEX, Binary, Base64, etc... Encoder/Decoder] Category:Standards organizations zh-min-nan:ANSI ko:ANSI ja:ANSI th:สถาบันมาตรฐานแห่งชาติของสหรัฐอเมริกา

Lumen (unit)

The lumen (symbol: lm) is the SI unit of luminous flux.

Definition

1 lm = 1 cd·sr = 1 cd·m²·m^–2

SI multiples

Explanation

One lumen is the luminous flux emitted by a light source that puts out one candela of luminous intensity over a solid angle of one steradian. Alternatively, an isotropic one-candela light source will put out a total luminous flux of exactly

4\pi

lumens. A standard 100 watt incandescent light bulb puts out around 1500 lumens. See the article on incandescent light bulbs for the specific efficiency of various types of electric light sources.

Links

[http://www.jracademy.com/~ewotawa/CandelaM.html Candela: The SI Unit of Luminous Intensity]

SI photometry units

Category:Photometry Category:Units of luminous flux Category:SI derived units ja:ルーメン

Cathode ray tube

The cathode ray tube or CRT, invented by Karl Ferdinand Braun, is the display device that was traditionally used in most computer displays, video monitors, televisions and oscilloscopes. The CRT developed from Philo Farnsworth's work was used in all television sets until the late 20th century and the advent of plasma screens, LCDs, DLP, OLED displays, and other technologies. As a result of this technology, television continues to be referred to as "The Tube" well into the 21st century, even when referring to non-CRT sets.

Apparatus description

The earliest version of the CRT was a cold-cathode diode, a modification of the Crookes tube with a phosphor-coated screen, sometimes called a Braun tube. The first version to use a hot cathode was developed by J. B. Johnson (who gave his name to the term Johnson noise) and H. W. Weinhart of Western Electric and became a commercial product in 1922. Cathode rays exist in the form of streams of high speed electrons emitted from the heating of cathode inside a vacuum tube. The released electrons form a beam within the cathode ray tube due to the voltage difference applied in the two electrodes, and the direction of this beam is then altered either by a magnetic or electric field to swap over the surface at the fluorescent screen (anode), covered by phosphorescent material (often transition metals or rare earths). Light is emitted at the instant that electrons hit the surface of that material. In case of a television and modern computer monitors, the entire front area of the tube is scanned in a fixed pattern called a raster, and a picture is created by modulating the intensity of the electron beam according to the programme's video signal. The beam in all modern TV sets is scanned with a magnetic field applied to the neck of the tube with a "magnetic yoke", a set of coils driven by electronic circuits. This usage of electromagnets to change the electron beam's original direction is known to be "magnetic deflection". In case of an oscilloscope, the intensity of the electron beam is kept constant, and the picture is drawn by steering the beam along an arbitrary path. Usually, the horizontal deflection is proportional to time, and the vertical deflection is proportional to the signal. The tube for this kind of use is longer and narrower, and deflection is done by applying an electrical field via deflection plates built into the tube's neck. The use of an electrical field (so-called "electrostatic deflection") allows the electron beam to be steered much more rapidly than with a magnetic field, where the inductance of the electromagnets imposes relatively severe limits on the frequency range that can be accurately reproduced. The electron beam source is the electron gun, producing the stream of electrons by thermionic emission and then focusing it to a thin beam. The gun was often mounted slightly off-axis, as it accelerated not only electrons but also ions resulting from outgassing of the internal tube components and from an imperfect vacuum. The ions are heavier than electrons, therefore they are less likely to be deflected by the magnetic field from the deflection coils, and in older constructions with in-axis guns they were bombarding the phosphor in the center of the screen and causing its deterioration; some very old black and white TV sets show browning of the center of the screen, known as ion burn. The combination of an off-axis mounting of electron guns and permanent magnets bending the electron beam back in the desired direction forms an ion trap; the ions were not deflected enough so they struck the neck of the tube instead of the screen and harmlessly dissipated. This system was later replaced with aluminium coating of the phosphor. The internal side of the phosphor layer is often covered with a layer of aluminium. The phosphors are usually poor electrical conductors, which leads to deposition of residual charge on the screen, effectively decreasing the energy of the impacting electrons due to electrostatic repulsion (an effect known as "sticking"). The aluminium layer is connected to the conductive layer inside the tube, disposing of this charge. It also reflect the phosphor light in the desired direction towards the viewer, and protects the phosphor from ion bombardment. aluminium Graphical displays for early computers used vector monitors, a type of CRT similar to the oscilloscope. Here, the beam would trace straight lines between arbitrary points, repeatedly refreshing the display as quickly as possible. Vector monitors were used in many computer displays as well as by some late 1970s to mid 1980s arcade games such as Asteroids. Vector displays for computers did not noticeably suffer the display artifacts of aliasing and pixelization, but were limited in that they could display only a shape's outline, and only a very small amount of rather largely-drawn text. (Because the speed of refresh was roughly inversely proportional to how many vectors needed to be drawn, "filling" an area using many individual vectors was impractical as was the display of a large amount of text.) Some vector monitors are capable of displaying several colors using either an ordinary tri-color CRT or two phosphor layers (so called "penetration color"). In these dual-layer tubes, by controlling the strength of the electron beam, electrons could be made to reach (and illuminate) either or both phosphor layers, typically producing green, orange, or red. Other graphical displays used storage tubes including Direct View Bistable Storage Tubes (DVBSTs). These CRTs inherently stored the image and did not require periodic refreshing. Some displays for early computers (those that needed to display more text than was practical using vectors, or required high speed for photographic output) used Charactron CRTs. These used a perforated metal character mask ("Stencil") to shape a wide electron beam to form a selected character shape on the screen. The electronics could quickly select a character on the mask with one set of deflection circuits, while selecting the position to display the character at with a second set of deflection circuits, and then just turn on the beam briefly to draw that character. Graphics could still be drawn by selecting the unneeded position on the mask corresponding to the code for a space (when drawing a space the beam was simply kept off), which had a small round hole in the center instead of being solid, and draw this as with other displays. Many of these various types of early computer display CRTs use "slow" or long persistance phosphor, to reduce flicker for the operator. Stencil Stencil Color tubes use three different materials which specifically emit red, green, and blue light, closely packed together in strips (in aperture grille designs) or clusters (in shadow mask CRTs). There are three electron guns, one for each color, and each gun can reach only the dots of one color, as the grille or mask absorbs electrons that would otherwise hit the wrong phosphor. The outer glass allows the light generated by the phosphor out of the monitor, but (for color tubes) it must block dangerous X-rays generated by the impact of the high energy electron beam. For this reason, the glass is made of leaded glass (sometimes called "lead crystal"). Because of this and other shielding, and protective circuits designed to prevent the anode voltage rising too high, the X-ray emission of modern CRTs is well within safety limits. CRTs have a pronounced triode characteristic, which results in significant gamma (a nonlinear relationship between beam current and light intensity). In early televisions, screen gamma was an advantage because it acted to compress the screen contrast. The gamma characteristic exists today in all digital video systems. However, in some systems where a linear response is required, as in desktop publishing, gamma correction is applied. CRT displays accumulate static electrical charge on the screen, unless protective measures are taken. This charge does not pose a safety hazard, but can lead to significant degradation of image quality through attraction of dust particles to the surface of the screen. Unless the display is regularly cleaned with a dry cloth or special cleaning tissue (using ordinary household cleaners may damage anti-glare protective layer on the screen), after a few months the brightness and clarity of the image drops significantly.

Other technologies

It is likely that technologies such as plasma displays, liquid crystal displays, and other newer technologies will eventually make CRT-based displays mostly obsolete, because the new designs are less bulky and consume less power. As of mid-2003, LCDs are becoming directly comparable in price to CRTs, with LCDs forming 30% of the computer display market by value. However, color CRTs still find adherents in computer gaming, due to their very quick response time, and in the printing and TV broadcasting industries for their better color fidelity and contrast.

Magnets

Magnets should never be put next to a color CRT, as they may cause magnetization of the shadow mask, which will cause incorrect colors to appear in the magnetized area and may be expensive to have corrected. Most modern television sets and nearly all newer computer monitors have a built-in degaussing coil. This coil creates a brief, alternating magnetic field from standard 50 or 60 Hz household power upon power-up which decays in strength as a resistor in the circuit increases resistance with its increasing temperature as a result of the current passing through it. The alternating magnetic field created is sufficient enough to shake off most cases of shadow mask magnetization. It is also possible to purchase or to build your own external degaussing coil which can aid in demagnetizing older sets or in cases where the built-in coil was not effective. A soldering gun (a soldering iron will not work as it does not contain a large transformer which produces a large alternating magnetic field) may also be used to degauss a monitor by holding it up to the center of the monitor with the hot tip end facing safely AWAY from the glass (and yourself!) and while holding down the on button, slowly moving the gun in ever wider concentric circles past the edge of the monitor until the shimmering colors can no longer be seen. This may need to be repeated several times to remove severe magnetization. In extreme cases, high power magnets such as the now popular neodymium iron boron, or NIB magnets, can actually deform the shadow mask. This type of damage is considered permanent and will render the CRT mostly useless. However, subjecting an old black and white television or monochrome (green screen, amber screen) computer monitor to magnets is generally harmless. This can be used as a demonstration tool and children should even be encouraged to do this so that they may see the immediate and dramatic effect of a magnetic field on moving charged particles, provided they are informed to never do the same with a color tube.

Health danger

Some believe the electromagnetic fields emitted by CRT monitors constitute a health danger to the functioning of living cells. Exposure to these fields is far lower at distances of 85 cm or farther. It is also less intensive for the display's user than for a person located behind it. CRTs also emit very small amounts of X-rays as a result of the electron beam's bombardment of the shadow mask/aperture grille and phosphors. Almost all of this radiation is blocked by the thick leaded glass in the screen so the amount of radiation escaping the front of the monitor is mostly harmless. The Food and Drug Administration regulations in 21 CFR 1020 are used to strictly limit, for instance, television receivers to 0.5 milliroentgens per hour (mR/h) (0.13 µC/(kg·h) (at a distance of 5 cm from any external surface and as mentioned above, most CRT emissions fall well below this limit.[http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=1020.10] Old CRTs may also have used toxic phosphors, although that is much less common today. An implosion or other breaking of the glass envelope could release these toxic phosphors. And because of the X-ray hazard, the glass envelopes of most modern CRTs are made from heavily leaded glass. The lead in this glass may represent an environmental hazard, especially in the presence of acid rain leaching through landfills. The constant refreshing of a CRT can cause seizures in epileptics, if they are photosensitive. Filters are available to reduce these effects. A high refresh rate (above 75 Hz) also helps to negate these effects. CRTs operate at very high voltages. These voltages can persist long (several days) after the device containing the CRT has been switched off and unplugged. (Modern circuits contain bleeder resistors to ensure the high-voltage supply is discharged to safe levels within a couple of minutes at most.) Do not tamper with devices containing CRT tubes unless you have proper engineering training and have taken appropriate precautions. Since the CRT contains a vacuum, care should be taken to prevent implosion.

High vacuum safety

Because CRTs "contain" a strong vacuum, they store a large amount of mechanical energy; they can implode very forcefully if the outer glass envelope is damaged. Most modern CRTs used in televisions and computer displays include a bonded, multi-layer faceplate that prevents implosion if the faceplate is damaged, but the bell of the CRT (back portions of the glass envelope) offers no such protection. Certain specialized CRTs (such as those used in oscilloscopes) do not even offer a bonded faceplate; these CRTs require an external plastic faceplate or other cover to render them implosion safe while in use. Before the use of bonded faceplates one of the hazards would be that a broken neck or envelope would cause the neck and electron gun to be propelled by atmosperic pressure at such a velocity that it would erupt through the face of the tube. When handling or disposing of a CRT, you must take steps to avoid creating an implosion hazard for you or your trash removal service. The most simple and safe method to make the tube safe is to identify the small sealed glass nib at the far back of the tube (this may be obscured by the electrical connector) and then (while wearing safety glasses and gloves) filing a small nick across this and then to break it off using a pair of pliers. A loud sucking sound will be heard as the air enters the tube, releasing the vacuum. One must be very cautious not to break the neck of the tube when it is evacuated since there is no plastic coating preventing shattering of the glass. High vacuum and high voltage can be dangerous.

External links

- [http://members.chello.nl/~h.dijkstra19/page3.html The Cathode Ray Tube site] ko:음극선관 ja:ブラウン管

LCD

:LCD redirects here. For other meanings of LCD, see LCD (disambiguation). LCD (disambiguation) electrodes. The shapes of these electrodes will determine the dark shapes that will appear when the LCD is turned on. Vertical ridges are etched on the surface so the liquid crystals are in line with the polarized light.

Twisted nematic liquid crystals.

Glass substrate with common electrode film (ITO) with horizontal ridges to line up with the horizontal filter.

Horizontal filter film to block/allow through light.

Reflective surface to send light back to viewer.

]] LCD (disambiguation) A liquid crystal display (LCD) is a thin, flat display device made up of any number of color or monochrome pixels arrayed in front of a light source or reflector. It is prized by engineers because it uses very small amounts of electric power, and is therefore suitable for use in battery-powered electronic devices. Each pixel (picture element) consists of a column of liquid crystal molecules suspended between two transparent electrodes, and two polarizing filters, the axes of polarity of which are perpendicular to each other. Without the liquid crystals between them, light passing through one would be blocked by the other. The liquid crystal twists the polarization of light entering one filter to allow it to pass through the other. The molecules of the liquid crystal have electric charges on them. By applying small electrical charges to transparent electrodes over each pixel or subpixel, the molecules are twisted by electrostatic forces. This changes the twist of the light passing through the molecules, and allows varying degrees of light to pass (or not pass) through the polarizing filters. Before applying an electrical charge, the liquid crystal molecules are in a relaxed state. Charges on the molecules cause these molecules to align themselves in a helical structure, or twist (the "crystal"). In some LCDs, the electrode may have a chemical surface that seeds the crystal, so it crystallizes at the needed angle. Light passing through one filter is rotated as it passes through the liquid crystal, allowing it to pass through the second polarized filter. A small amount of light is absorbed by the polarizing filters, but otherwise the entire assembly is transparent. When an electrical charge is applied to the electrodes, the molecules of the liquid crystal align themselves parallel to the electric field, thus limiting the rotation of entering light. If the liquid crystals are completely untwisted, light passing through them will be polarized perpendicular to the second filter, and thus be completely blocked. The pixel will appear unlit. By controlling the twist of the liquid crystals in each pixel, light can be allowed to pass though in varying amounts, correspondingly illuminating the pixel. Many LCDs are driven to darkness by an alternating current, which disrupts the twisting effect, and become faint or transparent when no current is applied. To save cost in the electronics, LCDs are often multiplexed. In a multiplexed display, electrodes on one side of the display are grouped and wired together, and each group gets its own voltage source. On the other side, the electrodes are also grouped, with each group getting a voltage sink. The groups are designed so each pixel has a unique, unshared combination of source and sink. The electronics, or the software driving the electronics then turns on sinks in sequence, and drives sources for the pixels of each sink. Important factors to consider when evaluating an LCD monitor include resolution, viewable size, response time (sync rate), matrix type (passive or active), viewing angle, color support, brightness and contrast ratio, aspect ratio, and input ports (e.g. DVI or VGA).

Brief history

Pioneering work on liquid crystals was undertaken in the late 1960s by the UK's Radar Research Establishment at Malvern. The team at RRE supported ongoing work by George Gray and his team at the University of Hull who ultimately discovered the cyanobiphenyl liquid crystals (which had all of the correct stability and temperature properties for application in LCDs). The first operational LCD was based on the Dynamic Scattering Mode (DSM) and was introduced in 1968 by a group at RCA in the USA headed by George Heilmeier. Heilmeier founded Optel, which introduced a number of LCDs based on this technology. In 1969, the twisted nematic field effect in liquid crystals was discovered by James Fergason at Kent State University in the USA, and in 1971 his company ILIXCO (now LXD Incorporated) produced the first LCDs based on it, which soon superseded the poor-quality DSM types.

Transmissive and reflective displays

LCDs can be either transmissive or reflective, depending on the location of the light source. A transmissive LCD is illuminated from the back by a backlight and viewed from the opposite side (front). This type of LCD is used in applications requiring high luminance levels such as computer displays, televisions, personal digital assistants, and mobile phones. The illumination device used to illuminate the LCD in such a product usually consumes much more power than the LCD itself. Reflective LCDs, often found in digital watches and calculators, are illuminated by external light reflected by a (sometimes) diffusing reflector behind the display. This type of LCD can produce darker 'blacks' than the transmissive type since light must pass through the liquid crystal layer twice and thus is attenuated twice, however because the reflected light is also attenuated twice in the translucent parts of the display image contrast is usually poorer than a transmissive display. The absence of a lamp significantly reduces power consumption, allowing for longer battery life in battery-powered devices; small reflective LCDs consume so little power that they can rely on a photovoltaic cell, as often found in pocket calculators. Transflective LCDs work as either transmissive or reflective LCDs, depending on the ambient light. They work reflectively when external light levels are high, and transmissively in darker environments via a low-power backlight.

Color displays

In color LCDs each individual pixel is divided into three cells, or subpixels, which are colored red, green, and blue, respectively, by additional filters. Each subpixel can be controlled independently to yield thousands or millions of possible colors for each pixel. Older CRT monitors employ a similar method for displaying color. Color components may be arrayed in various pixel geometries, depending on the monitor's usage.

Passive-matrix and active-matrix

LCDs with a small number of segments, such as those used in digital watches and pocket calculators, have a single electrical contact for each segment. An external dedicated circuit supplies an electric charge to control each segment. This display structure is unwieldy for more than a few display elements. Small monochrome displays such as those found in personal organizers, or older laptop screens have a passive-matrix structure employing supertwist nematic (STN) or double-layer STN (DSTN) technology (DSTN corrects a color-shifting problem with STN). Each row or column of the display has a single electrical circuit. The pixels are addressed one at a time by row and column addresses. This type of display is called a passive matrix because the pixel must retain its state between refreshes without the benefit of a steady electrical charge. As the number of pixels (and, correspondingly, columns and rows) increases, this type of display becomes increasingly less feasible. Very slow response times and poor contrast are typical of passive-matrix LCDs. For high-resolution color displays such as modern LCD computer monitors and televisions, an active matrix structure is used. A matrix of thin-film transistors (TFTs) is added to the polarizing and color filters. Each pixel has its own dedicated transistor, which allows each column line to access one pixel. When a row line is activated, all of the column lines are connected to a row of pixels and the correct voltage is driven onto all of the column lines. The row line is then deactivated and the next row line is activated. All of the row lines are activated in sequence during a refresh operation. Active-matrix displays are much brighter and sharper than passive-matrix displays of the same size, and generally have quicker response times.

Active matrix technologies

Main article: TFT LCD

IPS

In-plane switching or IPS is an lcd technology which changes the position of individual pixels in relation to the rest of the display. This helps alleviate common problems with LCD viewing angles.

VA

TN

In very simple terms TN (twisted nematic) mode LC displays rotate the plane of polarisation of light passing through them. As voltage is applied the molecules change orientation defeating the light twisting action. Place a TN cell between crossed polarisers and you create a "light valve". With no voltage applied the polarisation is twisted by the LC allowing it to pass through the crossed polarisers. Apply voltage and the twisting is defeated creating a black state. By careful voltage control any grey level or transmission can be achieved.

Quality control

Some LCD panels have defective transistors, causing permanently lit or unlit pixels. Unlike integrated circuits, LCD panels with a few defective pixels are usually still usable. It is also economically prohibitive to discard a panel with just a few bad pixels because LCD panels are much larger than ICs. Manufacturers have different standards for determining a maximum acceptable number of defective pixels. The following table presents the maximum acceptable number of defective pixels for IBM's ThinkPad laptop line. Image:lcd_defects.png LCD panels are more likely to have defects than most ICs due to their larger size. In this example, a 12" SVGA LCD has 8 defects and a 6" wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the LCD panel would be a 0% yield. (The standard is much higher now due to fierce competition between manufacturers and improved quality control. An LCD panel with 4 defective pixels is usually considered defective and customers can request an exchange for a new one.) The location of a defective pixel is also important. Often manufacturers relax their requirements when defective pixels are in the center of the viewing area.

Zero-power displays

The zenithal bistable device (ZBD), developed by QinetiQ (formerly DERA), can retain an image without power. The crystals may exist in one of two stable orientations (Black and "White") and power is only required to change the image. [http://www.zbddisplays.com/ ZBD Displays] is a spin-off company from QinetiQ who manufacture both grayscale and colour ZBD devices. A French company, [http://www.nemoptic.com/ Nemoptic], has developed another zero-power, paper-like LCD technology which has been mass-produced in Taiwan since July 2003. This technology is intended for use in low-power mobile applications such as e-books and wearable computers. Zero-power LCDs are in competition with electronic paper.

Drawbacks

LCD technology still has a few drawbacks in comparison to some other display technologies. While CRTs are capable of displaying multiple video resolutions, each with the same quality, LCD displays usually produce the crispest images in a "native resolution". Secondly, LCD displays generally have a lower contrast ratio than that on a plasma display or CRT. This is due to their "light valve" nature: some light always leaks out making black grey. Thirdly, LCDs have longer response time than their plasma and CRT counterparts, creating ghosting and mixing when images rapidly change; this caveat however is continually improving as the technology progresses. Finally the viewing angle of a LCD is usually less than that of most other display technologies thus reducing the number of people who can conveniently view the same image. However, this negative has been capitalised upon by an electronics company, allowing multiple TV outputs from the same LCD screen just by changing the angle from where the TV is seen. Such a set can also show two different images to one viewer, providing 3-D. LCD screens also occasionally suffer from image persistence, which is similar to screen burn on CRT displays.

External links

- [http://www.pencomputing.com/frames/textblock_display_types.html Consumer guide to LCD types]
- [http://electronics.howstuffworks.com/lcd.htm How LCDs Work]
- [http://www.pcreview.co.uk/articles/Consumer-Advice/LCD_vs_CRT/ LCD vs CRT]
- [http://techref.massmind.org/techref/lcds.htm Source code and examples for driving small LCD displays]
- [http://www.piclist.com/techref/io/lcd/pic.htm Source code and examples for driving LCD displays with the Microchip PIC embedded controllers]
- [http://www.geocities.com/dinceraydin/lcd/index.html LCD Simulators for smaller character and graphics LCDs]
- [http://www.lcdmonitor.org/ LCD Monitor] - Covers basics, frequently asked questions, and product database.
- [http://www.lci.kent.edu Liquid Crystal Institute (Kent State University)]
- [http://www.lxdinc.com LXD Incorporated] - Technical Information
- [http://www.xbitlabs.com/articles/other/display/lcd-guide.html X-bit’s Guide: Contemporary LCD Monitor Parameters and Characteristics]
- [http://www.techmind.org/lcd/ LCD Monitor Technology and Tests] - test patterns to aid setting up and evalution/analysis of modern LCD computer screens, and description of some practical benefits and shortfalls of LCD compared to CRT
- http://www.avdeals.com/classroom/what_is_tft_lcd.htm ja:液晶ディスプレイ

DLP

:For political parties using this acronym, see Democratic Labour Party. Digital Light Processing (DLP) is a technology used in projectors and projection televisions. DLP was originally developed by Texas Instruments, and they remain the sole manufacturer of such technology, though many licensees market products based on their chipsets. In DLP projectors, the image is created by microscopically small mirrors laid out in a matrix on a semiconductor chip, known as a Digital Micromirror Device (DMD). Each mirror represents one pixel in the projected image. The number of mirrors corresponds to the resolution of the projected image: 800×600, 1024×768, and 1280×720 matrices are some common DMD sizes. These mirrors can be repositioned rapidly to reflect light either through the lens or on to a heatsink (called a light dump in Barco terminology). The rapid repositioning of the mirrors (essentially switching between 'on' and 'off') allows the DMD to vary the intensity of the light being reflected out through the lens, creating shades of grey in addition to white (mirror in 'on' position), and black (mirror in 'off' position). There are two primary methods by which DLP projection systems create a color image, those utilized by single-chip DLP projectors, and those used by three-chip projectors.

Single-chip projectors

In a projector with a single DMD chip, colors are produced by placing a color wheel between the lamp and the DMD where it is reflected out through the optics. The color wheel is usually divided into four sectors: the primary colors: red, green, and blue, and an additional clear section to boost brightness. Since the clear sector reduces color saturation, in some models it may be effectively disabled, and in others it is omitted altogether. The DMD chip is synchronized with the rotating motion of the color wheel so that the green component is displayed on the DMD when the green section of the color wheel is in front of the lamp. The same is true for the red and blue sections. The red, green, and blue images are thus displayed sequentially at a sufficiently high rate that the observer sees the composite "full color" image. In early models, this was one rotation per frame. Later models spin the wheel at two or three times the frame rate, and some also repeat the color pattern twice around the wheel, meaning the sequence may be repeated up to six times per frame. primary colors

The DLP "Rainbow Effect"

This visual artifact is best described as brief flashes of perceived red, blue, and green "shadows" observed most often when the projected content features bright/white objects on a mostly dark/black background (the scrolling end credits of many movies being a common example). Some people perceive these rainbow artifacts all of the time, while others say they only see them when they let their eyes pan across the image. Yet others do not notice the artifact at all. The effect is likely rooted in the concept of the flicker fusion threshold. The image to the right shows how a white circle looks to a camera while panning horizontally, using a long exposure. The white light is visibly split into into its colored components. The rainbow effect occurs when this is visible to the naked eye. The multiple images of the circle represent the individual frames of video, and are unrelated to the rainbow effect. The manufacturers of single-chip DLP projection systems use color wheels rotating at higher speeds, or with more color segments in order to minimize the appearance of the artifacts.

Three-chip projectors

A three-chip DLP projector uses a prism to split light from the lamp, and each primary color of light is then routed to its own DMD chip, then recombined and routed out through the lens. Single-chip DLP systems are capable of displaying 16.7 million colors, whereas three-chip DLP systems can display up to 35 trillion colors. Three-chip projectors do not suffer from the "rainbow effect", since all three color components (red, green, and blue) are being generated simultaneously.

Market place

DLP is rapidly becoming a major player in the rear-projection TV market, having sold two million systems and achieved a 10% market share. Over 50 manufacturers offered models during the 2004 holiday season, up from 18 the previous year. DLP chips currently constitute 5% of Texas Instrument's total sales. Small standalone projection units (also called front projectors) using DLP technology have become very popular for office presentation and home theater duties.
- Pros: Smooth, jitter-free images; good color depth and contrast; no burn-in; DLP rear projection TVs are smaller, thinner and lighter than CRT-based models.
- Cons: In single chip designs, some people observe a "rainbow effect".

DLP and LCoS

The most similar competing system to DLP is known as LCoS (Liquid Crystal on Silicon), which creates images using a stationary mirror mounted on the surface of a chip, and uses a liquid crystal matrix, to control how much light is reflected.

External links

- [http://www.dlp.com/dlp_technology/includes/demo_flash.asp?bhcp=1 DLP Demo by Texas Instruments] (Flash)
- [http://www.dlp.com/dlp_technology/dlp_technology_overview.asp DLP Overview by Texas Instruments]
- [http://www.dlpseeit.com DLP... See It!] Resource page on DLP and TVs in general
- [http://www.projectorcentral.com/lcd_dlp_update.htm "The Great Technology War: LCD vs. DLP"] (projectorcentral.com)
- [http://www.projectorcentral.com/lcos.htm What's so hot about LCOS technology?] A comparison of DLP and LCoS
- [http://www.dlpmovies.com/index.php DLPmovies.com] A directory of DLP-enabled cinemas
- [http://electronics.howstuffworks.com/dlp.htm Howstuffworks.com DLP] Howstuffworks.com's article on DLPs Category:Electronics Category:Display technology

Texas Instruments

Texas Instruments (), better known in the electronics industry as TI, is a company based in Dallas, Texas, renowned for developing and commercializing semiconductor and computer technology.

History

Texas Instruments was founded by Cecil H. Green, J. Erik Jonsson, Eugene McDermott and Patrick E. Haggerty. On December 6, 1941, the four men purchased Geophysical Service Incorporated (GSI), a pioneering provider of seismic exploration services to the petroleum industry. During World War II, GSI built electronics for the U.S. Army Signal Corps and the U.S. Navy. After the war, GSI continued to produce electronics, and in 1951 the company changed its name to Texas Instruments; GSI became a wholly-owned subsidiary of the new company. An early success story for TI-GSI came in the 1950's when GSI was able (under a Top Secret government contract) to monitor the Soviet Union's underground nuclear weapons testing from outcrop bedrock found in Oklahoma. It is said that the US government knew the results of underground testing days before the Soviet Union could figure their own test results. 1951] In 1954, TI designed the first transistor radio. Also in the 1950s, the integrated circuit was developed independently by Jack Kilby of TI and Robert Noyce of Fairchild Semiconductor. Kilby's patent for a "solid circuit" was filed in 1958. The 7400 series of transistor-transistor logic (TTL) chips, developed by TI in the 1960s, popularized the use of integrated circuits in computer logic, and is in widespread use to this day. TI also invented the hand-held calculator in 1967, the single-chip microcomputer in 1971 and was assigned the first patent on a single-chip microprocessor (invented by Gary Boone) in 1973. (Note: TI is usually given credit with Intel for the almost-simultaneous invention of the microprocessor.) TI also continued to manufacture equipment for use in the seismic industry, and GSI continued to provide seismic services. After selling (and repurchasing) GSI, TI finally sold the company to Halliburton in 1988, at which point GSI ceased to exist as a separate entity. TI had two interesting problems with engineering and product development after the introduction of the semiconductor and the microprocessor. 1) Most of the chemicals, machinery and technologies needed to create semiconductors did not exist so TI had to "Invent" these. 2) The market was small for TI electronic components in the early days so TI had to "Invent" uses. For example, TI created the first wall mounted, computer controlled, home set-back thermostat in the late '70s but nobody would buy it mostly because of its cost. TI started an Industrial Controls division which built automated process control computers used in the paint and soup industry and was very successful. This business was eventually sold to Siemens AG. TI turned to military and government uses and had many electro-mechanical devices used in the Apollo rocket and Moon Lander.

Consumer electronics and computers

TI continued to be active in the consumer electronics market through the 1970s and 1980s. In 1978, Texas Instruments introduced the first single chip speech synthesizer and incorporated it in a product called the Speak & Spell, which was later immortalized in the movie E.T. the Extra-Terrestrial. Several spinoffs, such as the Speak & Read and Speak & Math, were introduced soon thereafter. In June 1979, TI entered the home computer market with the TI99/4, a competitor to such entries as the TRS-80 and the later Commodore VIC-20 and Commodore 64. It discontinued the TI99/4A (1981), the sequel to the 99/4, in late 1983 amidst an intense price war versus Commodore, Atari, and others. At the 1983 Winter CES TI showed models 99/2 and the Compact Computer 40 (CC-40), the latter aimed at professional users. The TI Professional (1983) ultimately joined the ranks of the many unsuccessful MS-DOS and x86-based--but non-compatible--competitors to the IBM PC. (Ironically, the founders of Compaq all came from TI.) The company for years successfully made and sold PC-compatible laptops before withdrawing from the market and selling its product line to Acer in 1997.

Defense electronics

TI was also active in the defense electronics market in the 1970s and 1980s, designing and manufacturing airborne radars and EO sensor systems, missiles, and laser-guided bombs. As the defense industry consolidated, TI sold its defense business to Raytheon in 1997.

TI today

Today, TI has four major lines of business: Semiconductors, DLP products, sensors and controls, and educational and productivity solutions.

Semiconductors

Semiconductor products account for approximately 85 percent of TI's revenues. TI has a market leading position in many different product areas, including digital signal processors in the TMS320 series, high speed digital-to-analog and analog-to-digital converters, power management solutions, and high performance analog circuits. Wireless communications has been a primary focus for TI, with around 50 percent of all cellular phones sold world-wide containing TI chips. TI also manufactures other semiconductor products, ranging from application-specific integrated circuits to microcontrollers. A division of TI Semiconductors called Application Specific Products (ASP) develops specific products that cater to a broad range of DSP applications, such as digital still cameras, DSL modems, cable modems, Voice over IP (VOIP), streaming media, speech compression and recognition, wireless LAN and residential gateway products, and RFID.

Digital Signal Processors

TI makes a broad range of digital signal processors OMAP microprocessor for multimedia applications. Some contains C55, ARM7, ARM9, or ARM11 cores.

Texas Instruments TMS320

:See main article on Texas Instruments TMS320
- TMS320C2xxx - 16 and 32 bit dsps optimised for control applications.
- C24X - 20 to 40MHz
- C28X - 100 to 150MHz
- TMS320C5xxx - 16 bit fixed point, low power. 100 to 300MHz
- TMS320C6xxx - family of High performance DSPs. 300 to 1000MHz
- Consists of the C62xx and C64xx fixed point families and the floating point C67xx Also the DM64X Digital Media processors. Others TMS320C33, TMS320C3x,TMS320C4x, TMS320C5x and TMS320C8x - multiprocessor dsp. Most of the older dsps are still available through [http://focus.ti.com/docs/military/catalog/products/militarycategoryproducttree.jhtml?templateId=5603&navigationId=8868&familyId=44 TIs military dsp site]

DLP products

TI is the sole source for digital light processing micro-mirror components, a technology used in video projectors and televisions.

Sensors and controls

Texas Instruments is a major OEM of sensor, control, protection, and RFID products for businesses.

Educational and productivity solutions

Texas Instruments is also notable for its calculator range, the TI-30 being one of the most popular early calculators. TI has also developed a line of graphing calculators, the first being the TI-81, and most popular being the TI-83 Plus. TI is often seen as the competitor to Hewlett-Packard in this regard, with fierce loyalties often arising.

TI calculator community

In the late 1990s, with the advent of TI's graphing calculator series, programming became popular among some students. The TI-8x series of calculators (beginning with the TI-81) came with a built-in BASIC interpreter, through which simple programs could be created. The TI-85 was the first TI calculator to allow assembly programming (via a shell called "ZShell"), and the TI-83 was the first in the series to receive native assembly. While the earlier BASIC programs were relatively simple applications or small games, the modern assembly-based programs rival what one might find on a Game Boy or PDA. Around the same time that these programs were first being written, personal webpages were becoming popular (through services such as Angelfire and GeoCities), and programmers began creating websites to host their work, along with tutorials and other calculator-relevant information. This led to the formation of TI calculator webrings, and eventually a few large communities, including the now-defunct TI-Files, and active [http://www.ticalc.org ticalc.org]. Ticalc.org is now seen as the authoritative source for programming for TI calculators, and at the site, one can find thousands of applications (including games, educational programs, and even simple operating environments), programming tutorials, calculator news, and discussion forums, among other things. TI graphing calculators generally fall into two distinct groups, those powered by the Zilog Z80 and those running on the Motorola 68000 series. Although a derivative of the Z80 was in the original Game Boy, the 68000 is far more powerful, and therefore better suited for gaming and processor intensive applications. The 68K calculators, which include the TI-89/Titanium, TI-92/Plus, and Voyage 200, are generally thought of more highly among TI community members than the Z80s. However, the newest of the Z80 series, the TI-84 Plus and TI-84 Plus Silver Edition, are becoming very popular with students new to the product line.

External links

- [http://www.ti.com Texas Instruments main web site]
- [http://education.ti.com Texas Instruments calculator website]
- [http://www.dlp.com DLP website]
- [http://www.ti.com/corp/docs/company/history/innov.shtml TI Key Innovations]
- [http://www.datamath.org www.datamath.org has a lot of information on ancient TI pocket calculators]
- [http://www.ticalc.org The most extensive TI calculator program/information archive] Category:Electronics companies of the United States Category:Home computer hardware companies Category:Companies based in Texas Category:Dallas/Ft. Worth-based companies Category:Companies traded on the New York Stock Exchange ja:テキサス・インスツルメンツ

Acer (company)

Acer is a Taiwan-based company and is one of the world's top five branded PC vendors. It owns the second largest computer retail chain in the country second only to Asus. Acer's product offering includes desktop and mobile PCs, servers and storage, displays, peripherals, and e-business solutions for business, government, education, and home users.

History

Multitech, which was founded in 1976, was renamed Acer in 1987. The pan Acer Group employs 39,000 people supporting dealers and distributors in over 100 countries. Revenues reached US $12.9 billion in 2002. The global headquarters is in Sijhih City, Taipei County, Taiwan.

Operations

Acer's subsidiary in Australia is Acer Computer Australia, which apart from being number 3 in the overall PC desktop and notebook market, is the leading vendor in key segments such as government and education. Acer's subsidiary in India is Acer India, which apart from being number 1 in the overall PC desktop and notebook market, is the leading vendor in key segments such as education. Acer's North American market share has slipped over the past few years while the European market share has gone up. Acer is trying to re-enter the NA market but whether it will work remains to be seen. Much of their success in Europe can be attributed to their sponsorship of the Ferrari Formula 1 Team and former F1 team, Prost Grand Prix. Acer is rumored to be sponsoring the American based Champ Car World Series soon.

Products

- Notebook
- TravelMate series
- TravelMate 8000 series
- Tablet PC series
- Aspire series
- Ferrari series
- Ferrari 4000 series : The first mass-produced notebook to be made with a carbon fibre chassis in the world.
- Personal Digital Assistant
- N Series
- Acer N30
- Acer N50
- Acer N50 Premium

Competitors

Major competitors of Acer include:
- Alienware
- Dell, Inc.
- HP/Compaq
- Gateway
- Lenovo
- Sony
- Toshiba

External links

- [http://global.acer.com/ Official website]
- [http://www.siliconvalleyinfozone.com/companies/Acer Silicon Valley InfoZone - Acer] Category:Electronics companies Category:Computer hardware companies Category:Companies of Taiwan nb:Acer

BenQ

BenQ Corporation is a Taiwan-based industry leader in digital lifestyle devices. It has expertise in the 3Cs (computing, communications, and consumer electronics.) The name reflects their corporate motto or vision: Bringing Enjoyment and Quality to life. The company was established in 1984, but was formerly known as Acer CM (Communications and Multimedia) before it was re-branded in December 2001. BenQ manufactures technology products, including communication and personal computer related products. Its principal products include TFT LCD monitors, plasma TVs, scanners and printers, digital cameras, projectors, CD/DVD rewriters, laptops, computer keyboards and mice, digital audio players, and mobile phones. The head office is located in Taoyuan, Taiwan. It mainly operates in North and Latin America, Eastern and Western Europe, the Middle East, China, South Asia, East Asia, SouthEast Asia and Australia. Effective October 1, 2005, BenQ acquired the mobile devices division of Germany's Siemens AG, becoming the 6th largest company in the mobile phone industry by accumulated market share. The acquisition results in a new business group, BenQ Mobile, of BenQ Corporation entirely dedicated to wireless communications. BenQ Corporation is part of the BenQ Group, which also includes AU Optronics.

External links

BenQ Global Sites

- [http://benq.com/ BenQ.Com (Corporate)]
- [http://www.benqmobile.com/ BenQ Mobile]
- [http://www.benq.us/ BenQ America (USA)]
- [http://www.benq.com.au/ BenQ Australia]
- [http://benq.at/ BenQ Austria]
- [http://benq.be/ BenQ Belgium]
- [http://benq.ca/ BenQ Canada]
- [http://www.benq.com.cn/ BenQ China]
- [http://benq.cz/ BenQ Czech Republic]
- [http://benq-eu.com/ BenQ Europe]
- [http://benq.fr/ BenQ France]
- [http://benq.de/ BenQ Germany]
- [http://www.benq.com.hk/ BenQ Hong Kong]
- [http://benq.hu/ BenQ Hungary]
- [http://www.benq.co.in/ BenQ India]
- [http://benq.it/ BenQ Italy]
- [http://www.benq.co.jp/ BenQ Japan]
- [http://ap.benq.com/kr/ BenQ Korea]
- [http://latam.benq.com/ BenQ Latin America]
- [http://benq.lv/ BenQ Latvia]
- [http://benq.lt/ BenQ Lithuania]
- [http://benq.co.ae/ BenQ Middle East]
- [http://benq.nl/ BenQ The Netherlands]
- [http://nordic.benq-eu.com/ BenQ Nordic]
- [http://benq.pl/ BenQ Poland]
- [http://benq.pt/ BenQ Portugal]
- [http://benq.ro/ BenQ Romania]
- [http://benq.ru/ BenQ Russia]
- [http://www.benq.com.sg/ BenQ Singapore]
- [http://benq.sk/ BenQ Slovakia]
- [http://benq.si/ BenQ Slovenia]
- [http://benq.es/ BenQ Spain]
- [http://benq.ch/ BenQ Switzerland]
- [http://www.benq.com.tw/ BenQ Taiwan]
- [http://www.benq.co.th/ BenQ Thailand]
- [http://benq.com.ua/ BenQ Ukraine]

BenQ group sites

- [http://www.auo.com/ AU Optronics]
- [http://www.daxontech.com/ Daxon Technology]
- [http://www.darfon.com/ Darfon Electronics]
- [http://www.airoha.com/ Airoha Technology]
- [http://www.candocom.com/ Cando Corp.] Category:Companies of Taiwan Category:Computer hardware companies Category:Brands Category:Portable Audio Player Manufacturers

Barco

Barco N.V. () is a display hardware manufacturer specialising in CRT projectors, LCD projectors, DLP projectors, LED displays and flat panel displays. Barco is an acronym that originally stood for Belgian American Radio COmpany. Barco is a world leader in professional markets, in which it offers display and visualization solutions. Based upon in-depth market knowledge, the company designs and develops solutions for large screen visualization, display solutions for life-critical applications, and systems for visual inspection. Currently Barco is active in the markets of traffic, surveillance, broadcasting, presentation, simulation and virtual reality, edutainment, events, media, digital cinema, air traffic control, defense & security, medical imaging, avionics, and textiles. Barco is headquartered in Kortrijk, Belgium, and has facilities for Sales & Marketing, Customer Support, R&D and Manufacturing in Europe, North America and Asia Pacific. The US headquarters is located in Kennesaw, Georgia, just outside of Atlanta. Worldwide, Barco employs more than 4200 people and realized sales of 672 million euro in 2004.

External link

- [http://www.barco.com/ Barco web site] Category:Aviation Category:Avionics Category:Companies of Belgium Category:Display technology Category:Medical imaging Category:Video and movie technology

Canon (company)

Canon Inc. , (in Japanese: キヤノン株式会社) is a Japanese company that is headquartered in Tokyo, Japan that specializes in imaging and optical products, including cameras, photocopiers and computer printers. The company was founded in 1933 with the name 精機光学研究所 (Seiki-kougaku-kenkyuujo or Precision Optical Instruments Laboratory) by the co-founder Yoshida Goro and his brother-in-law Uchida Saburo, funded by Takeshi Mitarai, a close friend of Uchida. Its original purpose was to research into the development of quality cameras. In June 1934 they released their first camera, the Kwanon, named after the Buddhist goddess of mercy. The following year the company name was changed to Canon in a more modern reflection of the name. The company's first cameras were Leica threadmount rangefinder clones. They closely followed the Leica specifications for the threadmount lens (M39) but added innovations including a switchable magnification combined viewfinder/rangefinder. Canon at first did not have its own optical factory, so they used lenses made by Nikon. But they soon started to make their own lenses under the Serenar brand. These lenses remain popular even now by users of Canon or Leica rangefinders. Despite the company's high profile in the consumer market for cameras and computer printers, most of the company revenue comes from the office products division, especially for analog and digital copiers, and its line of imageRUNNER digital multifunctional devices. Canon has also entered the digital displays market by teaming up with Toshiba to develop and manufacture flat panel televisions based on SED, a new type of display technology. Canon has also announced its intention to enter the projection television market as well. The official Japanese name of the company is キヤノン (kiyanon) not キャノン (kyanon): see the [http://www.canon.jp company home page] for confirmation. Canon's main competitors include Nikon, Konica Minolta, Leica, Pentax, Olympus, Sony, Epson, Kodak, Lomo, Hewlett-Packard and Xerox.

External links

- [http://www.canon.com/ Canon official site] Category:Electronics companies Category:Electronics companies of Japan ja:キヤノン th:แคนนอน (บริษัท)

Digital Projection International

Epson

Epson is one of the world's largest manufacturers of inkjet, dot-matrix and laser printers, scanners, desktop computers, business, multimedia and home theatre projectors, point of sale docket printers and cash registers, laptops, integrated circuits, LCD components and other associated electronic components. Based in Japan, they have numerous subsidiaries worldwide. The current CEO is Saburo Kusama. Net sales over 2004/2005 amounted to ¥1.479 trillion.

History

In 1961 Shinshu Seiki Co. (now known as Epson), Ltd was established to supply precision watch parts to Suwa Seikosha Co., Ltd. (now known as Seiko Instruments, Inc). When Suwa Seikosha was selected to be the official time keeper for the Tokyo Olympic games in 1964 a printing timer was required to time events, and Shinshu Seiki Co. started development of an electronic printer. In September 1968, the company launched the world's first miniprinter, the EP-101, which was soon incorporated into many calculators. In June 1975, the name Epson was coined after the next generation of the EP-101 was released to the public ("Son of EP-101" became "Son of EP" which in turn became "Epson"). In April of the same year Epson America Inc. was established to sell printers for Sinshu Seiki Co. In June 1978, the TX-80 eighty-column dot-matrix printer was released to the market, and was mainly used as a system printer for the Commodore PET Computer. After two years of further development, an improved model, the MX-80, was launched in October 1980. This was soon the best selling printer in the United States, despite the fact that it could only print text characters and symbols. In July 1982, the company officially named itself Epson Corporation and launched the world's first handheld computer, the HC-20 (HX-20), and in May 1983 the world's first portable color LCD TV was developed and launched by the company. In November 1985, Suwa Seikosha Co., Ltd. and Epson Corporation merged to form Seiko Epson Corporation. In 2004 Epson introduced their digital rangefinder camera, the R-D1, which takes Leica M mount lenses and Leica screw mount lenses with an adapter ring. This camera is notable for being the first digital rangefinder on the market. Because its sensor is smaller than the standard 35 mm film frame for which the lenses it takes are designed, lenses mounted on the R-D1 have the field of view of a lens 1.53 times as long as their stated focal length.

Expensive consumables

In recent years, Epson has been accused of manufacturing expensive consumables for their printers. It is also said that the company is forcing customers to purchase replacement ink cartridges before they are truly spent by using 'intelligence chips' to count how many pages have been printed in order to estimate the remaining ink, without actually monitoring the true ink levels. One disgruntled customer Bob Powell ([http://www.bobpowell.net/refill.htm]), claims to have dismantled an apparently empty ink tank from his Epson printer and found over 2 milliliters of ink remaining in the tank (25% of the original capacity). In July 2003, A Dutch Consumer Association it advised its 640,000 members to boycott Epson ink jet printers. The Netherlands-based organization alleged that Epson customers were unfairly charged for ink they could never use. Later that month however, the group retracted its call for a nationwide boycott of Epson products and issued a statement conceding that residual ink left in Epson cartridges is necessary for the printers to function properly. (PC World Friday, October 24, 2003 [http://www.pcworld.com/news/article/0,aid,113112,00.asp]). Epson leaves ink in the cartridges (and in fact have done so ever since they developed the piezo-electric head) due to the way the capping mechanism works. If the capping mechanism dries out, then the heads risk getting clogged, and thus an expensive repair will be necessary. The reason that the Dutch Consumer Association retracted their statement was because it was pointed out that Epson actually states how many pages (at usually a 5% coverage of a A4 sheet of paper) each cartridge can print. Further tests revealed that Epson did not mislead consumers.

External links

- [http://www.epson.com/ Epson worldwide]
- [http://www.epson.co.jp/e/ Epson Corporate]
- [http://www.epson.co.jp/e/company/milestones.htm Epson Milestones] Category:Electronics companies Category:Electronics companies of Japan
- ja:セイコーエプソン

Hewlett-Packard

The Hewlett-Packard Company , commonly known as HP, is a very large global company headquartered in Palo Alto, California, United States. Its products are concentrated in the fields of computing, printing, and digital imaging. It also sells software and services.

Company history

From '39 until the seventies

HP was founded in 1939 by Bill Hewlett and Dave Packard, who had both graduated from Stanford University in 1934, as a manufacturer of test and measurement instruments. Their first product was a precision audio oscillator, the Model 200A. Their innovation was the use of a light bulb as a temperature stabilized resistor in a critical portion of the circuit. This allowed them to sell the Model 200A for $54.40 when competitors were selling less stable oscillators for over US$ 200. Their company's name, Hewlett-Packard, was derived by their last names and had Bill not won the coin toss, the company today may have been known as Packard-Hewlett. One of the company's earliest customers was Walt Disney Productions, who bought eight Model 200B oscillators (at $71.50 each) for use in testing the Fantasound stereophonic sound system for the movie Fantasia.

First Computers

Fantasia HP is [http://www.wired.com/wired/archive/8.12/mustread.html?pg=11 acknowledged by] Wired magazine as the producer of the world's first personal computer, in 1968, the Hewlett-Packard 9100A. HP called it a desktop calculator because, as Bill Hewlett said, "If we had called it a computer, it would have been rejected by our customers' computer gurus because it didn't look like an IBM. We therefore decided to call it a calculator, and all such nonsense disappeared". An engineering triumph at the time, the logic circuit was produced without any integrated circuits; the assembly of the CPU having been entirely executed in discrete components. The mathematical functions and programmability rival the most powerful scientific calculators of the present day. With CRT readout, magnetic card storage, and printer the price was around $5000. The company earned global respect for a variety of products. They introduced the world's first handheld scientific electronic calculator in 1972 (the HP-35), the first handheld programmable in 1974 (the HP-65), the first alphanumeric, programmable, expandable in 1979 (the HP-41C), and the first symbolic and graphing calculator

Digital projector

Producers of projectors

See also

External links

Projection screen

Screens by installation type

Home theater screens and gain

Screen geometry and optics

Image brightness and contrast

Interactive whiteboard

How it works

Classroom Uses

Literature Reviews

Office Uses

Accessories

See also

Manufacturers

External Links

XGA

Clone hardware

Reference

ANSI

See also

External links

Lumen (unit)

Definition

SI multiples

Explanation

Links

SI photometry units

Cathode ray tube

Apparatus description

Other technologies

Magnets

Health danger

High vacuum safety

See also

External links

LCD

Brief history

Transmissive and reflective displays

Color displays

Passive-matrix and active-matrix

Active matrix technologies

IPS

VA

TN

Quality control

Zero-power displays

Drawbacks

See also

External links

DLP

Single-chip projectors

The DLP "Rainbow Effect"

Three-chip projectors

Market place

DLP and LCoS

See also

External links

Texas Instruments

History

Consumer electronics and computers

Defense electronics

TI today

Semiconductors

Digital Signal Processors

Texas Instruments TMS320

DLP products

Sensors and controls

Educational and productivity solutions

TI calculator community

See also

External links

Acer (company)

History

Operations

Products

Competitors

See also