Laser TV
Encyclopedia
Laser color television (in short, 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 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).
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 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, 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.
which are currently in use in projection display devices such as rear projection TV and front projectors. Current televisions are capable of displaying only 40% of the color gamut that humans can potentially perceive.
A Laser TV requires lasers 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 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 the basis for a mass produced frequency doubled laser.
The blue laser diodes became open 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 10 kHz repetition rate and various lengths are sent to 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.
History
The laser source for television or video display was originally proposed by Helmut K.V. Lotsch in the German Patent 1 193 844 . In December of 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 bankruptcy of Schneider AG, however, 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
Consumer Electronics Show
The International Consumer Electronics Show is a major technology-related trade show held each January in the Las Vegas Convention Center, Las Vegas, Nevada, United States. Not open to the public, the Consumer Electronics Association-sponsored show typically hosts previews of products and new...
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 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
Mitsubishi Electric
is a multinational electronics and information technology company headquartered in Tokyo, Japan. It is one of the core companies of the Mitsubishi Group....
Digital Electronics America, a key player in high-performance red-laser
and large-screen HDTV markets, unveiled their first commercial Laser TV, a 65" 1080p
1080p
1080p is the shorthand identification for a set of HDTV high-definition video modes that are characterized by 1080 horizontal lines of resolution and progressive scan, meaning the image is not interlaced as is the case with the 1080i display standard....
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.
Technology
Lasers may become an ideal replacement for the UHP lampsUHP (lamp)
The UHP, or Ultra High Performance, mercury arc lamp was developed by Philips in 1995 for use in commercial projection systems, home theatre projectors, MD-PTVs and video walls. Unlike other common mercury vapor lamps used in projection systems, it is not a metal halide lamp, but uses only mercury....
which are currently in use in projection display devices such as rear projection TV and front projectors. Current televisions are capable of displaying only 40% of the color gamut that humans can potentially perceive.
A Laser TV requires lasers 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 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 the basis for a mass produced frequency doubled laser.
The blue laser diodes became open available around 2010.
A VECSEL
VECSEL
A vertical-external-cavity surface-emitting-laser is a small semiconductor laser similar to a vertical-cavity surface-emitting laser...
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
Infrared
Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm...
-laser diodes is converted into visible light by means of extra-cavity waveguided second harmonic generation
Second harmonic generation
An optical frequency multiplier is a nonlinear optical device, in which photons interacting with a nonlinear material are effectively "combined" to form new photons with greater energy, and thus higher frequency...
. Laser-pulses with about 10 kHz repetition rate and various lengths are sent to a Digital Micromirror Device
Digital micromirror device
A digital micromirror device, or DMD, is an optical semiconductor that is the core of DLP projection technology, and was invented by Dr. Larry Hornbeck and Dr. William E. "Ed" Nelson of Texas Instruments in 1987....
where each mirror directs the pulse either onto screen or into the dump. Because the wavelengths are known all coatings can be optimized
Dielectric mirror
A dielectric mirror is a type of a mirror composed of multiple thin layers of dielectric material, typically deposited on a substrate of glass or some other optical material. By careful choice of the type and thickness of the dielectric layers, one can design an optical coating with specified...
to reduce reflections and therefore speckle.
Display Characteristics
- Maintain full power output for the lifespan of the laser; the picture quality won't degrade
- Have a very wide color gamutGamutIn color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
, which can produce up to 90% of the colors a human eye can perceive - Capable of displaying 3D stereoscopic video
- Can be projected onto any depth or shape surface while maintaining focus.