Misplaced Pages

#102897

88-463: The special case of one ray reduces the system to a monochrome display as, for example, in black and white television . This principle applies to a direct view display as well as to a (front or rear) laser projector system. Laser TV technology began to appear in the 1990s. In the 21st century, the rapid development and maturity of semiconductor lasers and other technologies gave it new advantages. The laser source for television or video display

176-632: A consumer product that displays images and videos measuring 100 inches (254 centimeters) with a full high-definition resolution of 1920 x 1080 pixels. It can project images onto the screen at a distance of 22 inches (56 centimeters). In China , the Sixth Session of the Seventh Council of the China Electronic Video Industry Association formally approved the establishment of a laser TV industry branch. The establishment of

264-421: A digital micromirror device where each mirror directs the pulse either onto screen or into the dump. Because the wavelengths are known all coatings can be optimized to reduce reflections and therefore speckle. Laser TV images are reflected by the screen and enter the human eye for imaging. According to ophthalmologists and professional evaluations, laser TV products are display products that are harmless to

352-421: A 65" 1080p model. A Popular Science writer was impressed by the color rendering of a Mitsubishi laser video display at CES 2008. Some even described it as being too intense to the point of seeming artificial. This laser TV, branded "Mitsubishi LaserVue TV", went on sale, November 16, 2008 for $ 6,999, but Mitsubishi's entire laser TV project was killed in 2012. LG introduced a front projected laser TV in 2013 as

440-563: A GaAs p-n junction light emitter and an electrically isolated semiconductor photodetector. On August 8, 1962, Biard and Pittman filed a patent titled "Semiconductor Radiant Diode" based on their findings, which described a zinc-diffused p–n junction LED with a spaced cathode contact to allow for efficient emission of infrared light under forward bias . After establishing the priority of their work based on engineering notebooks predating submissions from G.E. Labs, RCA Research Labs, IBM Research Labs, Bell Labs , and Lincoln Lab at MIT ,

528-432: A UHP. Current televisions are capable of displaying only 40% of the color gamut that humans can potentially perceive. Laser TVs utilize a laser light source, which offers several advantages over traditional LED and OLED technologies. The lasers typically use specific wavelengths of light, resulting in a wider color gamut and superior brightness. Unlike LED or OLED, laser light sources can produce purer colors, enhancing

616-657: A current source of a battery or a pulse generator and with a comparison to a variant, pure, crystal in 1953. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955. Braunstein observed infrared emission generated by simple diode structures using gallium antimonide (GaSb), GaAs, indium phosphide (InP), and silicon-germanium (SiGe) alloys at room temperature and at 77  kelvins . In 1957, Braunstein further demonstrated that

704-417: A flexible, fiber-optic waveguide then transports to a relatively small projection head. The projection head deflects the beam according to the pixel clock and emits it onto a screen at an arbitrary distance. Such laser projection techniques are used in handheld projectors , planetariums, and for flight simulators and other virtual reality applications. Due to the special features of laser projectors, such as

792-554: A glass window or lens to let the light out. Modern indicator LEDs are packed in transparent molded plastic cases, tubular or rectangular in shape, and often tinted to match the device color. Infrared devices may be dyed, to block visible light. More complex packages have been adapted for efficient heat dissipation in high-power LEDs . Surface-mounted LEDs further reduce the package size. LEDs intended for use with fiber optics cables may be provided with an optical connector. The first blue -violet LED, using magnesium-doped gallium nitride

880-455: A high depth of field , it is possible to project images or data onto any kind of projection surface, even non-flat. Typically, the sharpness, color space, and contrast ratio are higher than those of other projection technologies. For example, the on-off contrast of a laser projector is typically 50,000:1 and higher, while modern DLP and LCD projectors range from 1000:1 to 40,000:1. In comparison to conventional projectors, laser projectors provide

968-484: A laser TV is composed of laser light source, imaging module, circuit control system, and display. The technological progress of each of these units will help to increase market share compared to competing display technologies. Additionally, laser light sources have the advantages of lower manufacturing carbon emissions , higher color gamut , and higher energy efficiency . The advancement of laser television combined with better optical imaging technology can be lucrative in

SECTION 10

#1733092880103

1056-568: A longer lifetime, improved physical robustness, smaller sizes, and faster switching. In exchange for these generally favorable attributes, disadvantages of LEDs include electrical limitations to low voltage and generally to DC (not AC) power, the inability to provide steady illumination from a pulsing DC or an AC electrical supply source, and a lesser maximum operating temperature and storage temperature. LEDs are transducers of electricity into light. They operate in reverse of photodiodes , which convert light into electricity. Electroluminescence as

1144-481: A loudspeaker. Intercepting the beam stopped the music. We had a great deal of fun playing with this setup." In September 1961, while working at Texas Instruments in Dallas , Texas , James R. Biard and Gary Pittman discovered near-infrared (900 nm) light emission from a tunnel diode they had constructed on a GaAs substrate. By October 1961, they had demonstrated efficient light emission and signal coupling between

1232-500: A lower luminous flux output, but because of the extremely high contrast the brightness actually appears to be greater. In order to further accelerate the adoption of laser displays, the China Ministry of Science and Technology has prioritized the "engineering and development of next-generation laser display technology" as one of the eight major industrial development directions. As related technical problems are gradually resolved,

1320-557: A method for producing high-brightness blue LEDs using a new two-step process in 1991. In 2015, a US court ruled that three Taiwanese companies had infringed Moustakas's prior patent, and ordered them to pay licensing fees of not less than US$ 13 million. Two years later, in 1993, high-brightness blue LEDs were demonstrated by Shuji Nakamura of Nichia Corporation using a gallium nitride (GaN) growth process. These LEDs had efficiencies of 10%. In parallel, Isamu Akasaki and Hiroshi Amano of Nagoya University were working on developing

1408-514: A phenomenon was discovered in 1907 by the English experimenter Henry Joseph Round of Marconi Labs , using a crystal of silicon carbide and a cat's-whisker detector . Russian inventor Oleg Losev reported the creation of the first LED in 1927. His research was distributed in Soviet, German and British scientific journals, but no practical use was made of the discovery for several decades, partly due to

1496-567: A phosphor-silicon mixture on the LED using techniques such as jet dispensing, and allowing the solvents to evaporate, the LEDs are often tested, and placed on tapes for SMT placement equipment for use in LED light bulb production. Some "remote phosphor" LED light bulbs use a single plastic cover with YAG phosphor for one or several blue LEDs, instead of using phosphor coatings on single-chip white LEDs. Ce:YAG phosphors and epoxy in LEDs can degrade with use, and

1584-503: A red light-emitting diode. GaAsP was the basis for the first wave of commercial LEDs emitting visible light. It was mass produced by the Monsanto and Hewlett-Packard companies and used widely for displays in calculators and wrist watches. M. George Craford , a former graduate student of Holonyak, invented the first yellow LED and improved the brightness of red and red-orange LEDs by a factor of ten in 1972. In 1976, T. P. Pearsall designed

1672-482: A variety of competing technologies such as LCD, OLED , and upcoming Micro LED displays. Laser TVs must continue to develop to maintain a competitive advantage in order to occupy a larger market share. Monochrome display A monochrome monitor is a type of computer monitor in which computer text and images are displayed in varying tones of only one color, as opposed to a color monitor that can display text and images in multiple colors. They were very common in

1760-934: A wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs , and in seven-segment displays . Later developments produced LEDs available in visible , ultraviolet (UV), and infrared wavelengths with high, low, or intermediate light output, for instance, white LEDs suitable for room and outdoor lighting. LEDs have also given rise to new types of displays and sensors, while their high switching rates are useful in advanced communications technology with applications as diverse as aviation lighting , fairy lights , strip lights , automotive headlamps , advertising, general lighting , traffic signals , camera flashes, lighted wallpaper , horticultural grow lights , and medical devices. LEDs have many advantages over incandescent light sources, including lower power consumption,

1848-405: Is also an Xscreensaver hack called phosphor which emulates a long-persistence green screen and can be used as a terminal. LED A light-emitting diode ( LED ) is a semiconductor device that emits light when current flows through it. Electrons in the semiconductor recombine with electron holes , releasing energy in the form of photons . The color of the light (corresponding to

SECTION 20

#1733092880103

1936-484: Is because a monochrome monitor is made up of a continuous coating of phosphor and the sharpness can be controlled by focusing the electron beam; whereas on a color monitor, screen space is divided into triads of three phosphor dots (one red, one blue, one green) separated by a mask. The effective resolution of a color monitor is limited by the density of these triads. Furthermore, pixels in the source image will not align precisely to these triads, so moire effects will occur as

2024-416: Is deliberate on some monitors, known as "long persistence" monitors. These use the relatively long decay period of the phosphor glow to reduce flickering and eye strain. The colour scheme, grid layout of characters, and ghosting effects of the now-obsolete monochrome CRT screens have become an eye-catching visual shorthand for computer-generated text, frequently in "futuristic" settings. The opening titles of

2112-550: Is difficult but desirable since it takes advantage of existing semiconductor manufacturing infrastructure. It allows for the wafer-level packaging of LED dies resulting in extremely small LED packages. GaN is often deposited using metalorganic vapour-phase epitaxy (MOCVD), and it also uses lift-off . Even though white light can be created using individual red, green and blue LEDs, this results in poor color rendering , since only three narrow bands of wavelengths of light are being emitted. The attainment of high efficiency blue LEDs

2200-486: Is difficult on silicon , while others, like the University of Cambridge, choose a multi-layer structure, in order to reduce (crystal) lattice mismatch and different thermal expansion ratios, to avoid cracking of the LED chip at high temperatures (e.g. during manufacturing), reduce heat generation and increase luminous efficiency. Sapphire substrate patterning can be carried out with nanoimprint lithography . GaN-on-Si

2288-790: Is more apparent with higher concentrations of Ce:YAG in phosphor-silicone mixtures, because the Ce:YAG decomposes with use. The output of LEDs can shift to yellow over time due to degradation of the silicone. There are several variants of Ce:YAG, and manufacturers in many cases do not reveal the exact composition of their Ce:YAG offerings. Several other phosphors are available for phosphor-converted LEDs to produce several colors such as red, which uses nitrosilicate phosphors, and many other kinds of phosphor materials exist for LEDs such as phosphors based on oxides, oxynitrides, oxyhalides, halides, nitrides, sulfides, quantum dots, and inorganic-organic hybrid semiconductors. A single LED can have several phosphors at

2376-599: Is perceived as white light, with improved color rendering compared to wavelengths from the blue LED/YAG phosphor combination. The first white LEDs were expensive and inefficient. The light output then increased exponentially . The latest research and development has been propagated by Japanese manufacturers such as Panasonic and Nichia , and by Korean and Chinese manufacturers such as Samsung , Solstice, Kingsun, Hoyol and others. This trend in increased output has been called Haitz's law after Roland Haitz. Light output and efficiency of blue and near-ultraviolet LEDs rose and

2464-452: Is to use DLP technology for image display. Take the DMD chip as an example. The DMD chip is the imaging core component of a laser TV. There are millions of small mirrors arranged, and each small mirror can flip in the positive and negative directions at a frequency of tens of thousands of times per second. The light reflects directly on the screen through these small mirrors to form an image. Due to

2552-451: Is to use individual LEDs that emit three primary colors —red, green and blue—and then mix all the colors to form white light. The other is to use a phosphor material to convert monochromatic light from a blue or UV LED to broad-spectrum white light, similar to a fluorescent lamp . The yellow phosphor is cerium -doped YAG crystals suspended in the package or coated on the LED. This YAG phosphor causes white LEDs to appear yellow when off, and

2640-477: Is ½-⅓ of the same size LCD TV. Laser TVs are about one-tenth the weight of LCD TVs of the same size, and people can watch 80-inch laser TVs at a viewing distance of 3 meters. The video signal is introduced to the laser beam by an acousto-optic modulator (AOM) that uses a photorefractive crystal to separate the beam at distinct diffraction angles. The beam must enter the crystal at the specific Bragg angle of that AOM crystal. A piezoelectric element transforms

2728-761: The NeXT MegaPixel Display . Monochrome monitors are commonly available in three colors: if the P1 phosphor is used, the screen is green monochrome. If the P3 phosphor is used, the screen is amber monochrome. If the P4 phosphor is used, the screen is white monochrome (known as "page white"); this is the same phosphor as used in early television sets. An amber screen was claimed to give improved ergonomics, specifically by reducing eye strain; this claim appears to have little scientific basis. Well-known examples of early monochrome monitors are

Laser TV - Misplaced Pages Continue

2816-911: The Nobel Prize in Physics in 2014 for "the invention of efficient blue light-emitting diodes, which has enabled bright and energy-saving white light sources." In 1995, Alberto Barbieri at the Cardiff University Laboratory (GB) investigated the efficiency and reliability of high-brightness LEDs and demonstrated a "transparent contact" LED using indium tin oxide (ITO) on (AlGaInP/GaAs). In 2001 and 2002, processes for growing gallium nitride (GaN) LEDs on silicon were successfully demonstrated. In January 2012, Osram demonstrated high-power InGaN LEDs grown on silicon substrates commercially, and GaN-on-silicon LEDs are in production at Plessey Semiconductors . As of 2017, some manufacturers are using SiC as

2904-544: The U.S. patent office issued the two inventors the patent for the GaAs infrared light-emitting diode (U.S. Patent US3293513 ), the first practical LED. Immediately after filing the patent, Texas Instruments (TI) began a project to manufacture infrared diodes. In October 1962, TI announced the first commercial LED product (the SNX-100), which employed a pure GaAs crystal to emit an 890 nm light output. In October 1963, TI announced

2992-894: The VT100 from Digital Equipment Corporation , released in 1978, the Apple Monitor III in 1980, and the IBM 5151 , which accompanied the IBM PC model 5150 upon its 1981 release. The 5151 was designed to work with the PC's Monochrome Display Adapter (MDA) text-only graphics card , but the third-party Hercules Graphics Card became a popular companion to the 5151 screen because of the Hercules' comparatively high-resolution bitmapped 720×348 pixel monochrome graphics capability, much used for business presentation graphics generated from spreadsheets like Lotus 1-2-3 . This

3080-457: The human eye as a pure ( saturated ) color. Also unlike most lasers, its radiation is not spatially coherent , so it cannot approach the very high intensity characteristic of lasers . By selection of different semiconductor materials , single-color LEDs can be made that emit light in a narrow band of wavelengths from near-infrared through the visible spectrum and into the ultraviolet range. The required operating voltages of LEDs increase as

3168-451: The 3-subpixel model for digital displays. The technology uses a gallium nitride semiconductor that emits light of different frequencies modulated by voltage changes. A prototype display achieved a resolution of 6,800 PPI or 3k x 1.5k pixels. In a light-emitting diode, the recombination of electrons and electron holes in a semiconductor produces light (be it infrared, visible or UV), a process called " electroluminescence ". The wavelength of

3256-579: The Laser Television Industry Branch of the China Electronic Video Industry Association released the industry's first White Paper on Laser TV Eye Care in Shanghai. The white paper published the eye-care evaluation data of laser TVs and traditional LCD TVs by ophthalmology experts of China Electronics Technology Standardization Institute's CESI Laboratory and Peking Union Medical College Hospital , and made scientific suggestions on how to protect

3344-425: The ability to vary the brightness of individual pixels , thereby creating the illusion of depth and color, exactly like a black-and-white television. Typically, only a limited set of brightness levels was provided to save display memory which was very expensive in the '70s and '80s. Either normal/bright or normal/dim (1 bit) per character as in the VT100 or black, dark gray, light gray, white (2bit) per pixel like

3432-530: The basis for a mass-produced frequency doubled laser. The blue laser diodes became openly available around 2010. A VECSEL is a vertical cavity, and is composed of two mirrors. On top of one of them is a diode as the active medium. These lasers combine high overall efficiency with good beam quality. The light from the high power IR -laser diodes is converted into visible light by means of extra-cavity waveguided second-harmonic generation . Laser pulses with about 10kHz repetition rate and various lengths are sent to

3520-797: The blending of the colors. Since LEDs have slightly different emission patterns, the color balance may change depending on the angle of view, even if the RGB sources are in a single package, so RGB diodes are seldom used to produce white lighting. Nonetheless, this method has many applications because of the flexibility of mixing different colors, and in principle, this mechanism also has higher quantum efficiency in producing white light. There are several types of multicolor white LEDs: di- , tri- , and tetrachromatic white LEDs. Several key factors that play among these different methods include color stability, color rendering capability, and luminous efficacy. Often, higher efficiency means lower color rendering, presenting

3608-482: The characters very clear and sharply defined (thus easy to read) but generating an afterglow-effect (sometimes called a "ghost image") when the text scrolled down the screen or when a screenful of information was quickly replaced with another as in word processing page up/down operations. Other green screens avoided the heavy afterglow-effects, but at the cost of much more pixelated character images. The 5151, amongst others, had brightness and contrast controls to allow

Laser TV - Misplaced Pages Continue

3696-1083: The cladding and quantum well layers for ultraviolet LEDs, but these devices have not yet reached the level of efficiency and technological maturity of InGaN/GaN blue/green devices. If unalloyed GaN is used in this case to form the active quantum well layers, the device emits near-ultraviolet light with a peak wavelength centred around 365 nm. Green LEDs manufactured from the InGaN/GaN system are far more efficient and brighter than green LEDs produced with non-nitride material systems, but practical devices still exhibit efficiency too low for high-brightness applications. With AlGaN and AlGaInN , even shorter wavelengths are achievable. Near-UV emitters at wavelengths around 360–395 nm are already cheap and often encountered, for example, as black light lamp replacements for inspection of anti- counterfeiting UV watermarks in documents and bank notes, and for UV curing . Substantially more expensive, shorter-wavelength diodes are commercially available for wavelengths down to 240 nm. As

3784-417: The cost of reliable devices fell. This led to relatively high-power white-light LEDs for illumination, which are replacing incandescent and fluorescent lighting. Experimental white LEDs were demonstrated in 2014 to produce 303 lumens per watt of electricity (lm/W); some can last up to 100,000 hours. Commercially available LEDs have an efficiency of up to 223 lm/W as of 2018. A previous record of 135 lm/W

3872-488: The development of a commercial Laser TV were published as early as February 16, 2006 with a decision on the large-scale availability of laser televisions expected by early 2008. On January 7, 2008, at an event associated with the Consumer Electronics Show 2008, Mitsubishi Digital Electronics America, a key player in high-performance red-laser and large-screen HDTV markets, unveiled their first commercial Laser TV,

3960-480: The early days of computing, from the 1960s through the 1980s, before color monitors became widely commercially available. They are still widely used in applications such as computerized cash register systems, owing to the age of many registers. Green screen was the common name for a monochrome monitor using a green "P1" phosphor screen; the term is often misused to refer to any block mode display terminal, regardless of color, e.g., IBM 3279 , 3290 . Abundant in

4048-642: The early-to-mid-1980s, they succeeded Teletype terminals and preceded color CRTs and later LCDs as the predominant visual output device for computers. The most common technology for monochrome monitors was the CRT , although, e.g., plasma displays , were also used. Unlike color monitors, which display text and graphics in multiple colors through the use of alternating-intensity red, green, and blue phosphors , monochrome monitors have only one color of phosphor ( mono means "one", and chrome means "color"). All text and graphics are displayed in that color. Some monitors have

4136-539: The emitted wavelengths become shorter (higher energy, red to blue), because of their increasing semiconductor band gap. Blue LEDs have an active region consisting of one or more InGaN quantum wells sandwiched between thicker layers of GaN, called cladding layers. By varying the relative In/Ga fraction in the InGaN quantum wells, the light emission can in theory be varied from violet to amber. Aluminium gallium nitride (AlGaN) of varying Al/Ga fraction can be used to manufacture

4224-448: The energy of the photons) is determined by the energy required for electrons to cross the band gap of the semiconductor. White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device. Appearing as practical electronic components in 1962, the earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with

4312-491: The field of luminescence with research on radium . Hungarian Zoltán Bay together with György Szigeti patenting a lighting device in Hungary in 1939 based on silicon carbide, with an option on boron carbide, that emitted white, yellowish white, or greenish white depending on impurities present. Kurt Lehovec , Carl Accardo, and Edward Jamgochian explained these first LEDs in 1951 using an apparatus employing SiC crystals with

4400-548: The first Ghost in the Shell film and the digital rain effect of the Matrix trilogy science fiction films prominently feature computer displays with ghosting green text. A similar grid of amber text is used in the science fiction TV show Travelers . A free application for Linux terminal software called "Cool Retro Term" is available to accurately emulate old CRT Monochrome terminals for nostalgia or retrocomputing reasons. There

4488-602: The first commercial hemispherical LED, the SNX-110. In the 1960s, several laboratories focused on LEDs that would emit visible light. A particularly important device was demonstrated by Nick Holonyak on October 9, 1962, while he was working for General Electric in Syracuse, New York . The device used the semiconducting alloy gallium phosphide arsenide (GaAsP). It was the first semiconductor laser to emit visible light, albeit at low temperatures. At room temperature it still functioned as

SECTION 50

#1733092880103

4576-518: The first commercially available blue LED, based on the indirect bandgap semiconductor, silicon carbide (SiC). SiC LEDs had very low efficiency, no more than about 0.03%, but did emit in the blue portion of the visible light spectrum. In the late 1980s, key breakthroughs in GaN epitaxial growth and p-type doping ushered in the modern era of GaN-based optoelectronic devices. Building upon this foundation, Theodore Moustakas at Boston University patented

4664-721: The first high-brightness, high-efficiency LEDs for optical fiber telecommunications by inventing new semiconductor materials specifically adapted to optical fiber transmission wavelengths. Until 1968, visible and infrared LEDs were extremely costly, on the order of US$ 200 per unit, and so had little practical use. The first commercial visible-wavelength LEDs used GaAsP semiconductors and were commonly used as replacements for incandescent and neon indicator lamps , and in seven-segment displays , first in expensive equipment such as laboratory and electronics test equipment, then later in such appliances as calculators, TVs, radios, telephones, as well as watches. The Hewlett-Packard company (HP)

4752-418: The future home display market. Lasers are the most expensive components of laser televisions. More advanced laser diodes usually need more semiconductor materials to be manufactured, so reducing costs will remain an issue for the industrialization of laser TV for the foreseeable future. Existing laser TV products generally use imported semiconductor devices. In current large-screen display solutions, there are

4840-422: The image resolution approaches the limit imposed by the size of the phosphor triads. Monochrome monitors were used in almost all dumb terminals and were widely used in text-based applications such as computerized cash registers and point of sale systems because of their superior sharpness and enhanced readability. Some green screen displays were furnished with a particularly full/intense phosphor coating, making

4928-407: The important GaN deposition on sapphire substrates and the demonstration of p-type doping of GaN. This new development revolutionized LED lighting, making high-power blue light sources practical, leading to the development of technologies like Blu-ray . Nakamura was awarded the 2006 Millennium Technology Prize for his invention. Nakamura, Hiroshi Amano , and Isamu Akasaki were awarded

5016-494: The industry branch also symbolizes that the entire industrial chain connecting the upstream and downstream of the laser TV field is officially opened, in order to make the laser TV industry bigger and stronger. By 2022, sales of laser TVs in the Chinese market will exceed 1 million units, and sales will reach 11.8 billion CNY . Laser TV images are reflected by the screen and enter the human eye for imaging. The principle of laser TV

5104-430: The laser and keeping power consumption constant. There are several realizations of laser projectors, one example being based on the principle of a flying light spot writing the image directly onto a screen. A laser projector of this type consists of three main components — a laser source uses the video signal to provide modulated light composed of the three sharp spectral colors — red, green, and blue — which

5192-417: The light depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction, design features of the devices such as special optical coatings and die shape are required to efficiently emit light. Unlike a laser , the light emitted from an LED is neither spectrally coherent nor even highly monochromatic . Its spectrum is sufficiently narrow that it appears to

5280-420: The light produced is engineered to suit the human eye. Because of metamerism , it is possible to have quite different spectra that appear white. The appearance of objects illuminated by that light may vary as the spectrum varies. This is the issue of color rendition, quite separate from color temperature. An orange or cyan object could appear with the wrong color and much darker as the LED or phosphor does not emit

5368-437: The naked eye. The screen has no electromagnetic radiation , which is eye-protecting, healthy and comfortable. Compared with paper reading comfort, it is 20% higher. Laser TVs are mainly large-sized, with pure light sources, bright colors, and authenticity, also support 4K display resolution . Laser TVs have lower power consumption than LCD TVs of the same size. For example, a 100-inch laser TV consumes less than 300 watts, which

SECTION 60

#1733092880103

5456-445: The phosphors, the Ce:YAG phosphor converts blue light to green and red (yellow) light, and the PFS phosphor converts blue light to red light. The color, emission spectrum or color temperature of white phosphor converted and other phosphor converted LEDs can be controlled by changing the concentration of several phosphors that form a phosphor blend used in an LED package. The 'whiteness' of

5544-599: The photosensitivity of microorganisms approximately matches the absorption spectrum of DNA , with a peak at about 260 nm, UV LED emitting at 250–270 nm are expected in prospective disinfection and sterilization devices. Recent research has shown that commercially available UVA LEDs (365 nm) are already effective disinfection and sterilization devices. UV-C wavelengths were obtained in laboratories using aluminium nitride (210 nm), boron nitride (215 nm) and diamond (235 nm). There are two primary ways of producing white light-emitting diodes. One

5632-524: The popularization of laser TV products in households remains a major goal. At the end of December 2019, the CESI Laboratory of the China National Institute of Electronic Standardization and a team of ophthalmologists from Peking Union Medical College Hospital conducted a research project regarding the visual perception and eye strain of laser displays. In the study, 32 subjects were placed in

5720-521: The prototype was never developed further to a market-ready product. Proposed in 1966, laser illumination technology remained too costly to be used in commercially viable consumer products. At the Las Vegas Consumer Electronics Show in 2006, Novalux Inc ., developer of Necsel semiconductor laser technology, demonstrated their laser illumination source for projection displays and a prototype rear-projection "laser" TV. First reports on

5808-436: The required power at room temperature with an adequate lifetime. Instead, frequency doubling can be used to provide the green wavelengths. Several types of lasers can be used as the frequency doubled sources: fibre lasers, inter-cavity doubled lasers, external cavity doubled lasers, eVCSELs, and OPSLs (Optically Pumped Semiconductor Lasers). Among the inter-cavity doubled lasers, VCSELs have shown much promise and potential to be

5896-421: The rudimentary devices could be used for non-radio communication across a short distance. As noted by Kroemer Braunstein "…had set up a simple optical communications link: Music emerging from a record player was used via suitable electronics to modulate the forward current of a GaAs diode. The emitted light was detected by a PbS diode some distance away. This signal was fed into an audio amplifier and played back by

5984-508: The same environmental conditions comparing a laser TV and a LCD TV. Eye blinking frequency and the subjective perception score were compared and analyzed between the displays. The results found that watching the LCD TV for an extended period of time produced certain symptoms such as eye swelling, eye pain, photophobia, dry eyes , and blurred vision, while watching the laser TV, there was no obvious visual change or eye discomfort. On January 16, 2020,

6072-480: The same time. Some LEDs use phosphors made of glass-ceramic or composite phosphor/glass materials. Alternatively, the LED chips themselves can be coated with a thin coating of phosphor-containing material, called a conformal coating. The temperature of the phosphor during operation and how it is applied limits the size of an LED die. Wafer-level packaged white LEDs allow for extremely small LEDs. In 2024, QPixel introduced as polychromatic LED that could replace

6160-408: The space between the crystals allow some blue light to pass through in LEDs with partial phosphor conversion. Alternatively, white LEDs may use other phosphors like manganese(IV)-doped potassium fluorosilicate (PFS) or other engineered phosphors. PFS assists in red light generation, and is used in conjunction with conventional Ce:YAG phosphor. In LEDs with PFS phosphor, some blue light passes through

6248-547: The subsequent device Pankove and Miller built, the first actual gallium nitride light-emitting diode, emitted green light. In 1974 the U.S. Patent Office awarded Maruska, Rhines, and Stanford professor David Stevenson a patent for their work in 1972 (U.S. Patent US3819974 A ). Today, magnesium-doping of gallium nitride remains the basis for all commercial blue LEDs and laser diodes . In the early 1970s, these devices were too dim for practical use, and research into gallium nitride devices slowed. In August 1989, Cree introduced

6336-474: The substrate for LED production, but sapphire is more common, as it has the most similar properties to that of gallium nitride, reducing the need for patterning the sapphire wafer (patterned wafers are known as epi wafers). Samsung , the University of Cambridge , and Toshiba are performing research into GaN on Si LEDs. Toshiba has stopped research, possibly due to low yields. Some opt for epitaxy , which

6424-569: The team at Fairchild led by optoelectronics pioneer Thomas Brandt to achieve the needed cost reductions. LED producers have continued to use these methods as of about 2009. The early red LEDs were bright enough for use as indicators, as the light output was not enough to illuminate an area. Readouts in calculators were so small that plastic lenses were built over each digit to make them legible. Later, other colors became widely available and appeared in appliances and equipment. Early LEDs were packaged in metal cases similar to those of transistors, with

6512-424: The user to set their own compromise. Monochrome monitors are particularly susceptible to screen burn (hence the advent, and name, of the screensaver ), because the phosphors used are of very high intensity. Another effect of the high-intensity phosphors is an effect known as "ghosting", wherein a dim afterglow of the screen's contents is briefly visible after the screen has been blanked. This ghosting effect

6600-461: The very inefficient light-producing properties of silicon carbide, the semiconductor Losev used. In 1936, Georges Destriau observed that electroluminescence could be produced when zinc sulphide (ZnS) powder is suspended in an insulator and an alternating electrical field is applied to it. In his publications, Destriau often referred to luminescence as Losev-Light. Destriau worked in the laboratories of Madame Marie Curie , also an early pioneer in

6688-409: The video signal into vibrations in the crystal to create an image. A rapidly rotating polygonal mirror gives the laser beam the horizontal refresh modulation. It reflects off of a curved mirror onto a galvanometer -mounted mirror which provides the vertical refresh . Another way is to optically spread the beam and modulate each entire line at once, much like in a DLP, reducing the peak power needed in

6776-451: The viewing experience with more vibrant and accurate color reproduction. Additionally, laser light sources generally have a longer lifespan and are more energy-efficient, contributing to lower operational costs and environmental impact. Color television requires light in three distinct wavelengths —red, green, and blue. While red laser diodes are commercially available, there are no commercially available green laser diodes which can provide

6864-525: The visual health of adolescents. The market for laser TVs has seen an overall compound growth rate of 281% from 2014 to 2019. In 2019, the Hisense Laser TV 80L5 ranked first in the annual TV bestseller list. According to user survey data, more than 93% of users chose laser TVs because of the claimed benefits of eye health protection. Compared with LED backlit LCD TVs , laser TVs have many advantages in large-screen imaging. In terms of technical composition,

6952-469: The visual inertia of the human eye, the three primary colors that are irradiated on the same pixel at high speed are mixed and superimposed to form a color. Lasers may become an ideal replacement for the UHP lamps which are currently in use in projection display devices such as rear-projection TV and front projectors. LG claims a lifetime of 25,000 hours for their laser projector, compared to 10,000 hours for

7040-532: The wavelength it reflects. The best color rendition LEDs use a mix of phosphors, resulting in less efficiency and better color rendering. The first white light-emitting diodes (LEDs) were offered for sale in the autumn of 1996. Nichia made some of the first white LEDs which were based on blue LEDs with Ce:YAG phosphor. Ce:YAG is often grown using the Czochralski method . Mixing red, green, and blue sources to produce white light needs electronic circuits to control

7128-618: Was achieved by Nichia in 2010. Compared to incandescent bulbs, this is a huge increase in electrical efficiency, and even though LEDs are more expensive to purchase, overall lifetime cost is significantly cheaper than that of incandescent bulbs. The LED chip is encapsulated inside a small, plastic, white mold although sometimes an LED package can incorporate a reflector. It can be encapsulated using resin ( polyurethane -based), silicone, or epoxy containing (powdered) Cerium-doped YAG phosphor particles. The viscosity of phosphor-silicon mixtures must be carefully controlled. After application of

7216-415: Was engaged in research and development (R&D) on practical LEDs between 1962 and 1968, by a research team under Howard C. Borden, Gerald P. Pighini at HP Associates and HP Labs . During this time HP collaborated with Monsanto Company on developing the first usable LED products. The first usable LED products were HP's LED display and Monsanto's LED indicator lamp , both launched in 1968. Monsanto

7304-433: Was made at Stanford University in 1972 by Herb Maruska and Wally Rhines , doctoral students in materials science and engineering. At the time Maruska was on leave from RCA Laboratories , where he collaborated with Jacques Pankove on related work. In 1971, the year after Maruska left for Stanford, his RCA colleagues Pankove and Ed Miller demonstrated the first blue electroluminescence from zinc-doped gallium nitride, though

7392-582: Was much higher resolution than the alternative IBM Color Graphics Adapter 320×200 pixel, or 640×200 pixel graphic standard. It could also run most programs written for the CGA card's standard graphics modes. Monochrome monitors continued to be used, even after the introduction of higher resolution color IBM Enhanced Graphics Adapter and Video Graphics Array standards in the late 1980s, for dual-monitor applications. Pixel for pixel, monochrome CRT monitors produce sharper text and images than color CRT monitors. This

7480-595: Was originally proposed by Helmut K.V. Lotsch in the German Patent 1 193 844. In December 1977 H.K.V. Lotsch and F. Schroeter explained laser color television for conventional as well as projection-type systems and gave examples of potential applications. 18 years later the German-based company Schneider AG presented a functional laser-TV prototype at IFA'95 in Berlin , Germany . Due to the bankruptcy of Schneider AG, however,

7568-443: Was quickly followed by the development of the first white LED . In this device a Y 3 Al 5 O 12 :Ce (known as " YAG " or Ce:YAG phosphor) cerium -doped phosphor coating produces yellow light through fluorescence . The combination of that yellow with remaining blue light appears white to the eye. Using different phosphors produces green and red light through fluorescence. The resulting mixture of red, green and blue

7656-567: Was the first intelligent LED display, and was a revolution in digital display technology, replacing the Nixie tube and becoming the basis for later LED displays. In the 1970s, commercially successful LED devices at less than five cents each were produced by Fairchild Optoelectronics. These devices employed compound semiconductor chips fabricated with the planar process (developed by Jean Hoerni , ). The combination of planar processing for chip fabrication and innovative packaging methods enabled

7744-479: Was the first organization to mass-produce visible LEDs, using Gallium arsenide phosphide (GaAsP) in 1968 to produce red LEDs suitable for indicators. Monsanto had previously offered to supply HP with GaAsP, but HP decided to grow its own GaAsP. In February 1969, Hewlett-Packard introduced the HP Model 5082-7000 Numeric Indicator, the first LED device to use integrated circuit (integrated LED circuit ) technology. It

#102897