Digital Light Processing

DLP consists of chipsets based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While the DLP imaging device was invented by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for the DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays and also non-traditional embedded applications including medical, security, and industrial uses.

It is erroneously thought that "DLP" stands for "Digital Light Projection" or "Digital Light Processing". In fact, DLP is the full name of the technology, and is not an acronym.

DLP technology is used in DLP front projectors (standalone projection units for classrooms and business primarily), DLP rear projection television sets, and digital signs. It is also used in about 85% of digital cinema projection, and in additive manufacturing as a light source in some printers to cure resins into solid 3D objects.[1]

Smaller "pico" chipsets are used in mobile devices including cell phone accessories and projection display functions embedded directly into phones.

The DLP Logo
The DLP Logo
Christie Mirage 5000
The Christie Mirage 5000, a 2001 DLP projector

Digital micromirror device

Digital micromirror2
Diagram of a Digital micromirror showing the mirror mounted on the suspended yoke with the torsion spring running bottom left to top right (light grey), with the electrostatic pads of the memory cells below (top left and bottom right)

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). These mirrors are so small that DMD pixel pitch may be 5.4 µm or less.[2] Each mirror represents one or more pixels in the projected image. The number of mirrors corresponds to the resolution of the projected image (often half as many mirrors as the advertised resolution due to wobulation). 800×600, 1024×768, 1280×720, and 1920×1080 (HDTV) matrices are some common DMD sizes. These mirrors can be repositioned rapidly to reflect light either through the lens or onto a heat sink (called a light dump in Barco terminology).

Rapidly toggling the mirror between these two orientations (essentially on and off) produces grayscales, controlled by the ratio of on-time to off-time.

Color in DLP projection

There are two primary methods by which DLP projection systems create a color image: those used by single-chip DLP projectors, and those used by three-chip projectors. A third method, sequential illumination by three colored light emitting diodes, is being developed, and is currently used in televisions manufactured by Samsung.

Single-chip projectors

InFocus LP425z Single Chip DLP - internal components InFocus LP425z Single Chip DLP - 4-segment color wheel - Green Blue InFocus LP425z Single Chip DLP - 4-segment color wheel - Red Gray InFocus LP425z Single Chip DLP - top shroud with lightsink diffuser plate
InFocus LP425z Single Chip DLP - DMD Light Path
Interior view of a single-chip DLP projector, showing the light path. Light from the lamp enters a reverse-fisheye, passes through the spinning color wheel, crosses underneath the main lens, reflects off a front-surfaced mirror, and is spread onto the DMD (red arrows). From there, light either enters the lens (yellow) or is reflected off the top cover down into a light-sink (blue arrows) to absorb unneeded light. Top row shows overall components, closeups of 4-segment RGBW color wheel, and light-sink diffuser/reflection plate on top cover.

In a projector with a single DLP chip, colors are produced either by placing a color wheel between a white lamp and the DLP chip or by using individual light sources to produce the primary colors, LEDs or lasers for example. The color wheel is divided into multiple sectors: the primary additive colors: red, green, and blue, and in many cases white (clear). Newer systems substitute the primary subtractive colors cyan, magenta, and yellow for white. The use of the subtractive colors is part of the newer color performance system called BrilliantColor which processes the additive colors along with the subtractive colors to create a broader spectrum of possible color combinations on the screen.

The DLP 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, blue and other sections. The colors are thus displayed sequentially at a sufficiently high rate that the observer sees a composite "full color" image. In early models, this was one rotation per frame. Now, most systems operate at up to 10× the frame rate.

The black level of a single-chip DLP depends on how unused light is being disposed. If the unused light is scattered to reflect and dissipate on the rough interior walls of the DMD / lens chamber, this scattered light will be visible as a dim gray on the projection screen, when the image is fully dark. Deeper blacks and higher contrast ratios are possible by directing unused HID light away from the DMD / lens chamber into a separate area for dissipation, and shielding the light path from unwanted internal secondary reflections.

The color wheel "rainbow effect"

DLP rainbow effect
The rainbow effect found in DLP projectors utilizing a mechanical spinning wheel.

DLP projectors utilizing a mechanical spinning color wheel may exhibit an anomaly known as the "rainbow effect". This is best described as brief flashes of perceived red, blue, and green "shadows" observed most often when the projected content features high contrast areas of moving bright or white objects on a mostly dark or black background. Common examples are the scrolling end credits of many movies, and also animations with moving objects surrounded by a thick black outline. Brief visible separation of the colours can also be apparent when the viewer moves their eyes quickly across the projected image. Some people perceive these rainbow artifacts frequently, while others may never see them at all.

This effect is caused by the way the eye follows a moving object on the projection. When an object on the screen moves, the eye follows the object with a constant motion, but the projector displays each alternating color of the frame at the same location for the duration of the whole frame. So, while the eye is moving, it sees a frame of a specific color (red, for example). Then, when the next color is displayed (green, for example), although it gets displayed at the same location overlapping the previous color, the eye has moved toward the object's next frame target. Thus, the eye sees that specific frame color slightly shifted. Then, the third color gets displayed (blue, for example), and the eye sees that frame's color slightly shifted again. This effect is not perceived only for the moving object, but the whole picture. Multi-color LED-based and laser-based single-chip projectors are able to eliminate the spinning wheel and minimize the rainbow effect, since the pulse rates of LEDs and lasers are not limited by physical motion. "Three-chip DLP projectors have no color wheels, and thus do not manifest this [rainbow] artifact."[3]

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 DLP chip, then recombined and routed out through the lens. Three chip systems are found in higher-end home theater projectors, large venue projectors and DLP Cinema projection systems found in digital movie theaters.

According to, the three-chip projectors used in movie theaters can produce 35 trillion colors. The human eye is suggested to be able to detect around 16 million colors, which is theoretically possible with the single chip solution. However, this high color precision does not mean that three-chip DLP projectors are capable of displaying the entire gamut of colors we can distinguish (this is fundamentally impossible with any system composing colors by adding three constant base colors). In contrast, it is the one-chip DLP projectors that have the advantage of allowing any number of primary colors in a sufficiently fast color filter wheel, and so the possibility of improved color gamuts is available.

Light source

InFocus IN34
The InFocus IN34, a DLP projector

DLP technology is light-source agnostic and as such can be used effectively with a variety of light sources. Historically, the main light source used on DLP display systems has been a replaceable high-pressure xenon arc lamp unit (containing a quartz arc tube, reflector, electrical connections, and sometimes a quartz/glass shield), whereas most pico category (ultra-small) DLP projectors use high-power LEDs or lasers as a source of illumination.

Xenon arc lamps

For xenon arc lamps, during start-up, the lamp is ignited by a 5–20-kilovolt pulse from a current-regulating ballast to initiate an arc between two electrodes in the quartz tube. After warmup, the ballast's output voltage drops to approximately 60 volts while keeping the relative current high. As the lamp ages, the arc tube's electrodes wear out and light output declines somewhat, while waste heating of the lamp increases. The lamp's end of life is typically indicated by an LED on the unit or an onscreen text warning, necessitating replacement of the lamp unit.

When a lamp is operated past its rated lifespan, the efficiency declines significantly, the lightcast may become uneven, and the lamp starts to operate extremely hot, to the point that the power wires can melt off the lamp terminals. Eventually, the required startup voltage will also rise to the point where ignition can no longer occur. Secondary protections such as a temperature monitor may shut down the projector, but a thermally overstressed quartz arc tube can also crack and/or explode. However, practically all lamp housings contain heat-resistant barriers (in addition to those on the lamp unit itself) to prevent the red-hot quartz fragments from leaving the area.

LED-based DLPs

The first commercially available LED-based DLP HDTV was the Samsung HL-S5679W in 2006, which also eliminated the use of a color wheel. Besides long lifetime eliminating the need for lamp replacement and elimination of the color wheel, other advantages of LED illumination include instant-on operation and improved color, with increased color saturation and improved color gamut to over 140% of the NTSC color gamut. Samsung expanded the LED model line-up in 2007 with products available in 50-, 56- and 61-inch screen sizes. In 2008, the third generation of Samsung LED DLP products were available in 61" (HL61A750) and 67" (HL67A750) screen sizes.

Ordinary LED technology does not produce the intensity and high-lumen output characteristics required to replace arc lamps. The special patented LEDs used in all of the Samsung DLP TVs are PhlatLight LEDs, designed and manufactured by US-based Luminus Devices. A single RGB PhlatLight LED chipset illuminates these projection TVs. The PhlatLight LEDs are also used in a new class of ultra-compact DLP front projector commonly referred to as a "pocket projector" and have been introduced in new models from LG Electronics (HS101), Samsung electronics (SP-P400) and Casio (XJ-A series). Home Theater projectors will be the next category of DLP projectors that will use PhlatLight LED technology. At InfoComm, June 2008 Luminus and TI announced their collaboration on using their technology on home theater and business projectors and demonstrated a prototype PhlatLight LED-based DLP home theater front projector. They also announced products will be available in the marketplace later in 2008 from Optoma and other companies to be named later in the year.

Luminus Devices PhlatLight LEDs have also been used by Christie Digital in their DLP-based MicroTiles display system.[4] It is a modular system built from small (20 inch diagonal) rear projection cubes, which can be stacked and tiled together to form large display canvasses with very small seams. The scale and shape of the display can have any size, only constrained by practical limits.

Laser-based DLPs

The first commercially available laser-based DLP HDTV was the Mitsubishi L65-A90 LaserVue in 2008, which also eliminated the use of a color wheel. Three separate color lasers illuminate the digital micromirror device (DMD) in these projection TVs, producing a richer, more vibrant color palette than other methods. See the laser video display article for more information.

Digital cinema

DLP CINEMA. A Texas Instruments Technology - Photo Philippe Binant
DLP CINEMA. A Texas Instruments Technology
Texas Instruments, DLP Cinema Prototype System, Mark V, Paris, 2000 - Philippe Binant Archives
Texas Instruments, DLP Cinema Prototype Projector, Mark V, 2000
NEC Cinema DLP Beamer cebit2006
The NEC Cinema DLP projector in 2006

DLP Cinema systems have been deployed and tested commercially in theatres since 1999. In June 1999, Star Wars: Episode I – The Phantom Menace was the first movie to be entirely scanned and distributed to theaters. Four theaters installed digital projectors for the movie's release. The same was done for the traditional and computer-animated hybrid film Tarzan that same year. Later that year, Toy Story 2 was the first movie to be entirely created, edited, and distributed digitally, with more theaters installing digital projectors for its release. DLP Cinema was the first commercial digital cinema technology and is the leading digital cinema technology with approximately 85% market share worldwide as of December 2011. Digital cinema has some advantages over film because film can be subject to color fading, jumping, scratching and dirt accumulation. Digital cinema allows the movie content to remain of consistent quality over time. Today, most movie content is also captured digitally. The first all-digital live action feature shot without film was the 2002 release, Star Wars Episode II: Attack of the Clones.

DLP Cinema does not manufacture the end projectors, but rather provides the projection technology and works closely with Barco, Christie Digital and NEC who make the end projection units. DLP Cinema is available to theatre owners in multiple resolutions depending on the needs of the exhibitor. These include, 2K – for most theatre screens, 4K - for large theatre screens, and S2K, which was specifically designed for small theatres, particularly in emerging markets worldwide.

On February 2, 2000, Philippe Binant, technical manager of Digital Cinema Project at Gaumont in France, realized the first digital cinema projection in Europe[5] with the DLP CINEMA technology developed by Texas Instruments. DLP is the current market-share leader in professional digital movie projection,[6] largely because of its high contrast ratio and available resolution as compared to other digital front-projection technologies. As of December 2008, there are over 6,000 DLP-based Digital Cinema Systems installed worldwide.[7]

DLP projectors are also used in RealD Cinema and newer IMAX theatres for 3-D films.

Manufacturers and marketplace

2007TaipeiAudioVideoFair LaVEA DLPTV
56 inch DLP rear-projection TV

Since being introduced commercially in 1996, DLP technology has quickly gained market share in the front projection market and now holds greater than 50% of the worldwide share in front projection in addition to 85% market share in digital cinema worldwide. Additionally, in the pico category (small, mobile display) DLP technology holds approximately 70% market share. Over 30 manufacturers use the DLP chipset to power their projection display systems.


  • Smooth (at 1080p resolution), jitter-free images.
  • Perfect geometry and excellent grayscale linearity achievable.
  • Usually excellent ANSI contrast.
  • The use of a replaceable light source means a potentially longer life than CRTs and plasma displays (this may also be a con as listed below).
  • The light source is more-easily replaceable than the backlights used with LCDs, and on DLPs is often user-replaceable.
  • The light from the projected image is not inherently polarized.
  • New LED and laser DLP display systems more or less eliminate the need for lamp replacement.
  • DLP offers affordable 3D projection display from a single unit and can be used with both active and passive 3D solutions.
  • Lighter weight than LCD and plasma televisions.
  • Unlike their LCD and plasma counterparts, DLP screens do not rely on fluids as their projection medium and are therefore not limited in size by their inherent mirror mechanisms, making them ideal for increasingly larger high-definition theater and venue screens.
  • DLP projectors can process up to seven separate colors, giving them a wider color gamut.


Mitsubishi XD300U side
The rear panel of a Mitsubishi XD300U shows the output and input jacks which are available.
  • Some viewers are bothered by the "rainbow effect" present in colour-wheel models - particularly in older models (explained above). This can be observed easily by using a camera's digital viewfinder on projected content.
  • Rear projection DLP TVs are not as thin as LCD or plasma flat-panel displays (although approximately comparable in weight), although some models as of 2008 are becoming wall-mountable (while still being 10" to 14" thick)[8]
  • Replacement of the lamp / light bulb in lamp-based units. The life span of a arc lamp averages 2000–5000 hours and the replacement cost for these range from $99 – 350, depending on the brand and model. Newer generations' units use LEDs or lasers which effectively eliminate this issue, although replacement LED chips could potentially be required over the extended lifespan of the television set.
  • Some viewers find the high pitch whine of the color wheel to be an annoyance.[9][10][11] However, the drive system can be engineered to be silent and some projectors don't produce any audible color wheel noise.
  • Dithering noise may be noticeable, especially in dark image areas. Newer (post ~2004) chip generations have less noise than older ones.
  • Error-diffusion artifacts caused by averaging a shade over different pixels, since one pixel cannot render the shade exactly
  • Response time in video games may be affected by upscaling lag. While all HDTVs have some lag when upscaling lower resolution input to their native resolution, DLPs are commonly reported to have longer delays. Newer consoles that have HD output signals do not have this problem as long as they are connected with HD-capable cables.[12]
  • Reduced viewing angle as compared to direct-view technologies such as CRT, plasma, and LCD
  • May use more electricity, and generate more heat, than competing technologies.

DLP, LCD, and LCoS rear projection

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 (similar to a liquid crystal display) to control how much light is reflected.[13] DLP-based television systems are also arguably considered to be smaller in depth than traditional projection television.

See also


  1. ^ "How Digital Light Processing Works". Archived from the original on 21 February 2014. Retrieved 3 February 2014.
  2. ^ Texas Instruments. "DLP3010 Mobile HD Video and Data Display Description & parametrics". Retrieved 2014-10-13.
  3. ^ The Great Technology War: LCD vs. DLP. By Evan Powell, December 7, 2005. Accessed online at: Accessed on Dec. 27, 2011.
  4. ^ "Luminus Devices' PhlatLight LEDs Illuminate Christie MicroTile's New Digital Canvas Display". Businesswire. Archived from the original on 2012-09-19.
  5. ^ Cahiers du cinéma, n°hors-série, Paris, April 2000, p. 32.
  6. ^ Texas Business Archived 2012-01-26 at the Wayback Machine
  7. ^ TI (2008-02-15). "European Cinema Yearbook". Mediasalles. Retrieved 2008-02-15.
  8. ^
  9. ^ "DLP TV : Why Is There A Noise Coming From My DLP TV?". Archived from the original on 2010-10-05.
  10. ^ "Samsung LNT2653H 26-Inch LCD HDTV forum: High pitched noise".
  11. ^ "Ecoustics: Noise with the Samsung DLP HLP series".
  12. ^ "HDTVs and Video Game Lag: The Problem and the Solution". AVS Forum. 2005-07-11. Retrieved 2007-08-13.
  13. ^ "4 styles of HDTV". 2007-03-13. Retrieved 2007-08-13.

Further reading

External links

CRT projector

A CRT projector is a video projector that uses a small, high-brightness cathode ray tube as the image generating element. The image is then focused and enlarged onto a screen using a lens kept in front of the CRT face. The first color CRT projectors came out in the early 1950s. Most modern CRT projectors are color and have three separate CRTs (instead of a single, color CRT), and their own lenses to achieve color images. The red, green and blue portions of the incoming video signal are processed and sent to the respective CRTs whose images are focused by their lenses to achieve the overall picture on the screen. Various designs have made it to production, including the "direct" CRT-lens design, and the Schmidt-CRT, which employed a phosphor screen that illuminates a perforated spherical mirror, all within an evacuated "tube."

The image in the Sinclair Microvision "flat" CRT is viewed from the same side of the phosphor struck by the electron beam. The other side of the screen can be connected directly to a heat sink, allowing the projector to run at much brighter power levels than the more common CRT arrangement.Though systems utilizing projected video at one time almost exclusively used CRT projectors, they have largely been replaced by other technologies such as LCD projection and Digital Light Processing. Improvements in these digital video projectors, and their subsequent increased availability and desirability, resulted in a drastic decline of CRT projector sales by the early 2000s. As of 2012, very few (if any) new units are manufactured, though a number of installers do sell refurbished units, generally higher-end 8" and 9" models.

Digital micromirror device

The digital micromirror device, or DMD, is a micro-opto-electromechanical system (MOEMS) that is the core of the trademarked DLP projection technology from Texas Instruments (TI). The DMD was invented by solid state physicist and TI Fellow Emeritus Dr. Larry Hornbeck in 1987.The DMD project began as the Deformable Mirror Device in 1977 using micromechanical analog light modulators. The first analog DMD product was the TI DMD2000 airline ticket printer that used a DMD instead of a laser scanner.

A DMD chip has on its surface several hundred thousand microscopic mirrors arranged in a rectangular array which correspond to the pixels in the image to be displayed. The mirrors can be individually rotated ±10-12°, to an on or off state. In the on state, light from the projector bulb is reflected into the lens making the pixel appear bright on the screen. In the off state, the light is directed elsewhere (usually onto a heatsink), making the pixel appear dark.

To produce greyscales, the mirror is toggled on and off very quickly, and the ratio of on time to off time determines the shade produced (binary pulse-width modulation). Contemporary DMD chips can produce up to 1024 shades of gray (10 bits). See Digital Light Processing for discussion of how color images are produced in DMD-based systems.

The mirrors themselves are made out of aluminum and are around 16 micrometers across. Each one is mounted on a yoke which in turn is connected to two support posts by compliant torsion hinges. In this type of hinge, the axle is fixed at both ends and twists in the middle. Because of the small scale, hinge fatigue is not a problem and tests have shown that even 1 trillion (1012) operations do not cause noticeable damage. Tests have also shown that the hinges cannot be damaged by normal shock and vibration, since it is absorbed by the DMD superstructure.

Two pairs of electrodes control the position of the mirror by electrostatic attraction. Each pair has one electrode on each side of the hinge, with one of the pairs positioned to act on the yoke and the other acting directly on the mirror. The majority of the time, equal bias charges are applied to both sides simultaneously. Instead of flipping to a central position as one might expect, this actually holds the mirror in its current position. This is because attraction force on the side the mirror is already tilted towards is greater, since that side is closer to the electrodes.

To move the mirrors, the required state is first loaded into an SRAM cell located beneath each pixel, which is also connected to the electrodes. Once all the SRAM cells have been loaded, the bias voltage is removed, allowing the charges from the SRAM cell to prevail, moving the mirror. When the bias is restored, the mirror is once again held in position, and the next required movement can be loaded into the memory cell.

The bias system is used because it reduces the voltage levels required to address the pixels such that they can be driven directly from the SRAM cell, and also because the bias voltage can be removed at the same time for the whole chip, so every mirror moves at the same instant. The advantages of the latter are more accurate timing and a more cinematic moving image.

Display resolution

The display resolution or display modes of a digital television, computer monitor or display device is the number of distinct pixels in each dimension that can be displayed. It can be an ambiguous term especially as the displayed resolution is controlled by different factors in cathode ray tube (CRT) displays, flat-panel displays (including liquid-crystal displays) and projection displays using fixed picture-element (pixel) arrays.

It is usually quoted as width × height, with the units in pixels: for example, "1024 × 768" means the width is 1024 pixels and the height is 768 pixels. This example would normally be spoken as "ten twenty-four by seven sixty-eight" or "ten twenty-four by seven six eight".

One use of the term "display resolution" applies to fixed-pixel-array displays such as plasma display panels (PDP), liquid-crystal displays (LCD), Digital Light Processing (DLP) projectors, OLED displays, and similar technologies, and is simply the physical number of columns and rows of pixels creating the display (e.g. 1920 × 1080). A consequence of having a fixed-grid display is that, for multi-format video inputs, all displays need a "scaling engine" (a digital video processor that includes a memory array) to match the incoming picture format to the display.

For device displays such as phones, tablets, monitors and televisions, the use of the word resolution as defined above is a misnomer, though common. The term "display resolution" is usually used to mean pixel dimensions, the number of pixels in each dimension (e.g. 1920 × 1080), which does not tell anything about the pixel density of the display on which the image is actually formed: resolution properly refers to the pixel density, the number of pixels per unit distance or area, not total number of pixels. In digital measurement, the display resolution would be given in pixels per inch (PPI). In analog measurement, if the screen is 10 inches high, then the horizontal resolution is measured across a square 10 inches wide. For television standards, this is typically stated as "lines horizontal resolution, per picture height"; for example, analog NTSC TVs can typically display about 340 lines of "per picture height" horizontal resolution from over-the-air sources, which is equivalent to about 440 total lines of actual picture information from left edge to right edge.


An Eidophor was a television projector used to create theater-sized images from an analog video signal. The name Eidophor is derived from the Greek word-roots ‘eido’ and ‘phor’ meaning 'image' and 'bearer' (carrier). Its basic technology was the use of electrostatic charges to deform an oil surface.

Frame rate control

Frame rate control (FRC) is a method for achieving higher color quality in low color resolution display panels such as TN+film LCD.

Most TN panels represent colors using only 6 bits per RGB color, or 18 bit in total, and are unable to display the 16.7 million color shades (24-bit truecolor) that are available from graphics cards. Instead, they use a dithering method that combines adjacent pixels to simulate the desired shade.

FRC is a form of temporal dithering which cycles between different color shades with each new frame to simulate an intermediate shade. This can create a potentially noticeable 30 Hz flicker. FRC tends to be most noticeable in darker tones, while dithering appears to make the individual pixels of the LCD visible.This method is similar in principle to field-sequential color system by CBS and other sequential color methods such as used in Digital Light Processing (DLP).

8 bit TN+film panels with dithering are sometimes advertised as having "16.2 million colors".

Some panels now render HDR10 content with an 8-bit panel using frame rate control.

Fritz Fischer (physicist)

Fritz Fischer (9 February 1898, Signau BE, Switzerland – 28 December 1947, Zurich, Switzerland) was a technical physicist, engineer and inventor. He was married to Maud Schätti.

Fritz Fischer studied electrical engineering at the ETH Zurich from 1917 till 1921. Working at the Telephonwerke Albisrieden he improved the transmission quality of speech, whereupon he was called to the central laboratories of the mother company Siemens & Halske in Berlin. There he built the first remotely controlled ships and airplanes and investigated the physical properties of colour film. He was lecturer at the Technical University of Berlin.

1932 he received a call to the ETH Zurich, where he became professor and founded the Institute for Technical Physics. He developed and patented the Eidophor technique of displaying television pictures the size of cinema screens. Dr. Edgar Gretener, his chief assistant at the ETH, was project leader for the development of Eidophor. This project was transferred to a company founded by Gretener, which later became Gretag AG. After years of development, Eidophor achieved commercial success until Liquid Crystal Display LCD (another invention with important Swiss contributors) and Digital Light Processing DLP video projectors became available.

Other early assistants at his Institute were Hugo Thiemann (founding member of the Club of Rome), Gustav Guanella, Werner Lindecker and Erna Hamburger, who became famous on their own.

Professor Fritz Fischer was one of the important technical scientists of his day. He was co-founder together with Dr. Max Lattmann, his first Ph.D. graduate, of Contraves AG, a Swiss defence and aerospace company, now part of Rheinmetall Air Defence AG, Zurich.

Grating light valve

The grating light valve (GLV) is a "micro projection" technology which operates using a dynamically adjustable diffraction grating. It competes with other light valve technologies such as Digital Light Processing (DLP) and liquid crystal on silicon (LCoS) for implementation in video projector devices such as rear-projection televisions. The use of microelectromechanical systems (MEMS) in optical applications, which is known as optical MEMS or micro-opto-electro-mechanical structures (MOEMS), has enabled the possibility to combine the mechanical, electrical and optical components in very small scale.

Silicon Light Machines (SLM), in Sunnyvale CA, markets and licenses GLV technology with the capitalised trademarks Grated Light Valve and GLV, previously Grating Light Valve. The valve diffracts laser light using an array of tiny movable ribbons mounted on a silicon base. The GLV uses six ribbons as the diffraction gratings for each pixel. The alignment of the gratings is altered by electronic signals, and this displacement controls the intensity of the diffracted light in a very smooth gradation.

History of display technology

Electrically operated display devices have developed from electromechanical systems for display of text, up to all-electronic devices capable of full-motion 3D color graphic displays. Electromagnetic devices, using a solenoid coil to control a visible flag or flap, were the earliest type, and were used for text displays such as stock market prices and arrival/departure display times. The cathode ray tube was the workhorse of text and video display technology for several decades until being displaced by plasma, liquid crystal (LCD) and solid-state devices such as LEDs and OLEDs. With the advent of microprocessors and microelectronic devices, many more individual picture elements ("pixels") could be incorporated into one display device, allowing graphic displays and video.

John A. Pollock (businessman)

John A. Pollock, b. 1936, is a businessman and philanthropist, who was the president of his family's company, Electrohome, from 1972 to 2008. He also was the seventh chancellor of Wilfrid Laurier University, and held this position from March 31, 2008 to October 28, 2011.Pollock was born and raised in Kitchener, Ontario, Canada, obtaining a Bachelor of Applied Science degree from the University of Toronto, where he was President of the Alpha Delta Phi Fraternity and a Masters of Business Administration from Harvard University. He has also received Honorary Doctor of Laws degrees from both Wilfrid Laurier University and the University of Waterloo.

In 1972, he succeeded his father Carl A. Pollock as president of Electrohome, a Kitchener, Ontario-based electronics company founded by his grandfather Arthur Bell Pollock in 1907. Electrohome was widely known as the Canadian equivalent of US companies like General Electric and RCA. Pollock led the company into developing a number of different electronics products, both consumer and industrial, including specialized data displays for the New York Stock Exchange, large-screen projection televisions, reverse osmosis/ultrafiltration systems, and in the late 1970s and 1980s, custom monitors for many leading video games manufacturers including Atari and Sega. The company also had brief ventures in satellite television receivers and videotex hardware. In 1996 Pollock merged the Electrohome owned CKCO-TV, the first TV station in Kitchener-Waterloo, the company's other broadcasting properties, and holdings in CTV, with Baton Broadcasting. In 1997, Electrohome sold its interest in CTV and all broadcast holdings to Baton for cash and shares worth $270 Million Canadian dollars. Baton changed its name to CTV Television Network a year later, and has been the top rated Canadian television network since 2002. Under Pollock, Electrohome's most successful products were a line of industrial display projectors that evolved from single CRT monochrome data projectors into stereoscopic virtual reality projectors and digital movie theater projectors, based on the Texas Instruments Digital Light Processing technology. In 1999, Electrohome sold the projection systems division to Christie Digital, a leading film projector manufacturer. Electrohome eventually was dissolved in an orderly wind down in late 2008.

Pollock served on the boards of numerous companies including Thyssenkrupp Budd Canada Inc., Canadian General-Tower Ltd. and S.C. Johnson and Son Ltd. He was also active in many non-profit organizations, serving as a trustee with the Art Gallery of Ontario and as a board member with Cambridge Memorial Hospital, the Grand River Conservation Foundation and Junior Achievement of the Region of Waterloo. He was a member of the Advisory Board of the University of Western Ontario, the Board of Directors of the University of Waterloo, the Science Council of Canada and the Trillium Foundation of Ontario. He has also served as chairman of the Kitchener-Waterloo Art Gallery and St. John’s-Kilmarnock School, a private school serving the Waterloo Region area.

Pollock and his wife Joyce had four children.

LCD projector

An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD (liquid-crystal display) projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels (combination of polarizer, LCD panel and analyzer), individual pixels can be opened to allow light to pass or closed to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image.

Metal-halide lamps are used because they output an ideal color temperature and a broad spectrum of color. These lamps also have the ability to produce an extremely large amount of light within a small area; current projectors average about 2,000 to 15,000 American National Standards Institute (ANSI) lumens. Other technologies, such as Digital Light Processing (DLP) and liquid crystal on silicon (LCOS) are also becoming more popular in modestly priced video projection.

Large-screen television technology

Large-screen television technology developed rapidly in the late 1990s and 2000s. Various thin screen technologies are being developed, but only the liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been released on the public market. These technologies have almost completely displaced cathode ray tubes (CRT) in television sales, due to the necessary bulkiness of cathode ray tubes. However, recently released technologies like organic light-emitting diode (OLED) and not-yet released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are making their way to replace the first flat screen technologies in picture quality. The diagonal screen size of a CRT television is limited to about 40 inches because of the size requirements of the cathode ray tube, which fires three beams of electrons onto the screen, creating a viewable image. A larger screen size requires a longer tube, making a CRT television with a large screen (50 to 80 inches) unrealistic because of size. The aforementioned technologies can produce large-screen televisions that are much thinner.

Laser video display

Laser color television ( laser TV), or laser color video display utilizes two or more individually modulated optical (laser) rays of different colors to produce a combined spot that is scanned and projected across the image plane by a polygon-mirror system or less effectively by optoelectronic means to produce a color-television display. The systems work either by scanning the entire picture a dot at a time and modulating the laser directly at high frequency, much like the electron beams in a cathode ray tube, or by optically spreading and then modulating the laser and scanning a line at a time, the line itself being modulated in much the same way as with digital light processing (DLP).

The special case of one ray reduces the system to a monochromatic display as, for example, in black-and-white television. This principle applies to a display as well as to a (front or rear) projection technique with lasers (a laser video projector).


Photoswitch, or photo-electric switch, is a sensor that detects the presence of light or a change in its intensity. Photoswitches are one type of molecular machines, a class of molecules that can be switched between at least two distinct thermodynamically stable forms by the application of an external stimulus. The development of such devices is crucial in the framework of nanotechnology; nowadays, photoswitches are applied in a variety of places from scientific applications to residential light timers. Organic compounds have been deployed as photoswitches and a popular example of it is azobenzene.

RealD 3D

RealD 3D is a digital stereoscopic projection technology made and sold by RealD. It is currently the most widely used technology for watching 3D films in theaters (cinemas). Worldwide, RealD 3D is installed in more than 26,500 auditoriums by approximately 1,200 exhibitors in 72 countries as of June 2015.

Remote control

In electronics, a remote control is a component of an electronic device used to operate the device from a distance, usually wirelessly. For example, in consumer electronics, a remote control can be used to operate devices such as a television set, DVD player, or other home appliance, from a short distance. A remote control is primarily a convenience feature for the user, and can allow operation of devices that are out of convenient reach for direct operation of controls. In some cases, remote controls allow a person to operate a device that they otherwise would not be able to reach, as when a garage door opener is triggered from outside or when a Digital Light Processing projector that is mounted on a high ceiling is controlled by a person from the floor level.

Early television remote controls (1956–1977) used ultrasonic tones. Present-day remote controls are commonly consumer infrared devices which send digitally-coded pulses of infrared radiation to control functions such as power, volume, channels, playback, track change, heat, fan speed, or other features varying from device to device. Remote controls for these devices are usually small wireless handheld objects with an array of buttons for adjusting various settings such as television channel, track number, and volume. For many devices, the remote control contains all the function controls while the controlled device itself has only a handful of essential primary controls. The remote control code, and thus the required remote control device, is usually specific to a product line, but there are universal remotes, which emulate the remote control made for most major brand devices.

Remote control has continually evolved and advanced in the 2000s to include Bluetooth connectivity, motion sensor-enabled capabilities and voice control.

Television set

A television set or television receiver, more commonly called a television, TV, TV set, or telly, is a device that combines a tuner, display, and loudspeakers for the purpose of viewing television. Introduced in the late 1920s in mechanical form, television sets became a popular consumer product after World War II in electronic form, using cathode ray tubes. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for the first recorded media in the 1970s, such as Betamax, VHS and later DVD. It was also the display device for the first generation of home computers (e.g., Timex Sinclair 1000) and video game consoles (e.g., Atari) in the 1980s. In the 2010s flat panel television incorporating liquid-crystal displays, especially LED-backlit LCDs, largely replaced cathode ray tubes and other displays. Modern flat panel TVs are typically capable of high-definition display (720p, 1080i, 1080p) and can also play content from a USB device.

Texas Instruments

Texas Instruments Inc. (TI) is an American technology company that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally. Its headquarters are in Dallas, Texas, United States. TI is one of the top ten semiconductor companies worldwide, based on sales volume. Texas Instruments's focus is on developing analog chips and embedded processors, which accounts for more than 80% of their revenue. TI also produces TI digital light processing (DLP) technology and education technology products including calculators, microcontrollers and multi-core processors. To date, TI has more than 43,000 patents worldwide.Texas Instruments emerged in 1951 after a reorganization of Geophysical Service Incorporated, a company founded in 1930 that manufactured equipment for use in the seismic industry, as well as defense electronics. TI produced the world's first commercial silicon transistor in 1954, and designed and manufactured the first transistor radio in 1954. Jack Kilby invented the integrated circuit in 1958 while working at TI's Central Research Labs. TI also invented the hand-held calculator in 1967, and introduced the first single-chip microcontroller (MCU) in 1970, which combined all the elements of computing onto one piece of silicon.In 1987, TI invented the digital light processing device (also known as the DLP chip), which serves as the foundation for the company's award-winning DLP technology and DLP Cinema. In 1990, TI came out with the popular TI-81 calculator which made them a leader in the graphing calculator industry. In 1997, its defense business was sold to Raytheon, which allowed TI to strengthen its focus on digital solutions. After the acquisition of National Semiconductor in 2011, the company had a combined portfolio of nearly 45,000 analog products and customer design tools, making it the world's largest maker of analog technology components.


Wobulation is the known variation (or wobble) in a characteristic. For example, wobulation of advanced radar waveform modulations – where the repetition rate or centre frequency of a signal is changed in a repetitive fashion to reduce the probability of interception.

In large-screen television technology, wobulation is Hewlett-Packard's term for a form of interlacing designed for use with fixed pixel displays. The term is loosely derived from the word 'wobble' and was inspired by HP's work with the overlap of printing ink. Wobulation reduces the cost and complexity of components required for the creation of high resolution TVs.

Wobulation works by overlapping pixels. It does so by generating multiple sub-frames of data while an optical image shifting mechanism (e.g. the mirror of a digital micromirror device) then displaces the projected image of each sub-frame by a fraction of a pixel (e.g. one-half or one-third). The sub-frames are then projected in rapid succession, and appear to the human eye as if they are being projected simultaneously and superimposed. For example, a high-resolution HDTV video frame is divided into two sub-frames, A and B. Sub-frame A is projected, and then the miniature mirror on a digital micromirror device switches and displaces sub-frame B one half pixel length as it is projected. When projected in rapid succession, the sub-frames superimpose, and create to the human eye a complete and seamless image. If the video sub-frames are aligned so that the corners of the pixels in the second sub-frame are projected at the centers of the first, the illusion of double the resolution is achieved, like in an interlaced CRT display. Thus a lower resolution fixed pixel device using wobulation can emulate the picture of higher resolution fixed device, at a reduced cost.

As of 2007, wobulation is used only to double the horizontal resolution of a display, unlike CRT interlacing that doubles the vertical resolution. However, wobulation is capable of doubling the vertical and horizontal resolution of an image (2× wobulation).

While wobulation can in theory be used in many types of display devices, it is currently primarily used in displays using Digital Light Processing (DLP). DLP is a Texas Instruments (TI) technology which relies on a Digital Micromirror Device (DMD) chip. TI calls its implementation of wobulation 'SmoothPicture'. Horizontal wobulation used in current TI products allows a DMD chip with a 960×1080 mirror array to produce a 1920×1080 pixel picture; most recent designs employed in 3D DLP sets use "offset-diamond pixel layout", where the mirrors form a "checkerboard pattern" array. Also, the image overlap inherent in the use of wobulation eliminates the 'screen door' effect common on other fixed pixel displays such as plasma and LCD, but may in some implementations also create some reduction in sharpness. Wobulation is used by a number of TV manufacturers, including Hewlett-Packard, Mitsubishi, RCA, Samsung, and Toshiba.

Wobulation technology used in TVs is becoming obsolete, as manufacturers shift away from producing rear projection TVs.

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