Re: [Vo]: Optics question
Other display technologies in development or soon to be marketed include SED (surface conduction electron emission) and nanotube TV... http://news.com.com/Carbon+TVs+to+edge+out+liquid+crystal,+plasma/2100-1041_ 3-5512225.html and OLED (organic light emitting diodes)... http://www.audioholics.com/techtips/specsformats/organicOLEDsdisplays.php Harry
Re: [Vo]: Optics question
Mike Carrell wrote: One-paragraph articles about laser illuminators don't give all the relevant data. On the other hand, there is more detail in the rest of the article. - Jed Mike Carrell -- As Hoyte Stearns pointed out, upcoming DLP projection televisions will use an array of lasers instead of a bright light and color wheel. See: http://www.technologyreview.com/NanoTech/17651/ . . . the main advantage that lasers offer over traditional projection is an increased richness in colors, says Mooradian. The color of light produced by a laser is, by definition, spectrally narrow, varying less than one nanometer on either side of the peak wavelength. . . . The lasers should last longer than white lights, too. - Jed This Email has been scanned for all viruses by Medford Leas I.T. Department.
Re: [Vo]: Optics question
In reply to Mike Carrell's message of Mon, 8 Jan 2007 17:01:58 -0500: Hi, [snip] There is a misunderstanding of the nature of DLP technology. The active element is an array of tiny mirrors created by silicon machining techniques, one for each pixel. Each mirror can be tilted by a small angle under control from a TV signal. That tilt determines wihether the light falling on it goes to a location on the screen or to a dump. The average intensityof each pixel is determined by the fraction of time the mirror illuminates the screen. The individual mirrors do not scan, they only switch light to or away from one location on the screen. The optics, once fixed, are quite robust. The only variable is the lamp. which has finite life and must be changed. [snip] Thanks Mike. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
Re: [Vo]: Optics question
A bit of history. The first color TV system approved by the FCC was from CBS, which involved a color wheel in front of the CRT, or a belt going around the whole tube. This limited the CRT size, of course, and either slowed the refresh rate or demanded more transmission bandwidth. In a bet-your-company tour de force, RCA developed the compatable color TV system now used worldwide. It was RCA's crowning achievement, plus the technology for putting color and hi-fi sound on VHS tapes. The small size and very fast response of the DLP array makes a color wheel quite reasonable. It also enables better color rendition by the selection of filters. The red phosphor in color CRTs is a bit too orange for best rendition of reds, but that is necessary to get the needed brightness. A color wheel doesn't have that limitation. The competing LCD light valves cand use dichroic mirrors to merge images from three valve arrays, but that approach is apparently not making much commercial headway. Mike Carrell - On 1/8/07, Mike Carrell [EMAIL PROTECTED] wrote: There is a misunderstanding of the nature of DLP technology. The active element is an array of tiny mirrors created by silicon machining techniques, one for each pixel. You forget the spinning light filter for RGB. Truly a rube goldberg technology: http://www.dlp.com/ Terry This Email has been scanned for all viruses by Medford Leas I.T. Department.
Re: [Vo]: Optics question
As Hoyte Stearns pointed out, upcoming DLP projection televisions will use an array of lasers instead of a bright light and color wheel. See: http://www.technologyreview.com/NanoTech/17651/ . . . the main advantage that lasers offer over traditional projection is an increased richness in colors, says Mooradian. The color of light produced by a laser is, by definition, spectrally narrow, varying less than one nanometer on either side of the peak wavelength. . . . The lasers should last longer than white lights, too. - Jed
Re: [Vo]: Optics question
Part of the encoding process in compatable color television is transformationof the RGB signals from the camera into a two dimensional color space diagram with coordinates of chrominance and luminance. This is also used in JPEG encoding. The spectral sensitivity of the camera, projector, and eye are all different and internal compensations are necessary to produce a satisfactory image. The range of colors that can be reproduced in a display will depend on how deep into the red one can go without losing brightness; same with green and blue. LCD and DLP displays use filters with white light sources. CRTs are limited by what phosphors will do, as are the plasma displays [which are arrays of tiny fluorescent lamps]. Lasers produce pure colors, but there may also be limitations in how red the red, greeen the green and blue the blue. The purity of each color does not in itself guarantee fidelity or richness of the color display, unless the source colors map into the extremes of the chrominance-luminance space. One-paragraph articles about laser illuminators don't give all the relevant data. Mike Carrell -- As Hoyte Stearns pointed out, upcoming DLP projection televisions will use an array of lasers instead of a bright light and color wheel. See: http://www.technologyreview.com/NanoTech/17651/ . . . the main advantage that lasers offer over traditional projection is an increased richness in colors, says Mooradian. The color of light produced by a laser is, by definition, spectrally narrow, varying less than one nanometer on either side of the peak wavelength. . . . The lasers should last longer than white lights, too. - Jed This Email has been scanned for all viruses by Medford Leas I.T. Department.
Re: [Vo]: Optics question
A good idea but then it's a different beast altogether, it's a classical scanning laser display, and you must have only one steerable (or rotating multifaceted, one facet per line) mirror per laser source, not an array of micromirrors. The problem with scanning laser displays is that for a given display luminosity laser light is much more expensive than the light bulbs used in DLP displays. And less energy-efficient too I would think, even when taking into account the DLP's light dumping losses in question. Michel - Original Message - From: Robin van Spaandonk [EMAIL PROTECTED] To: vortex-l@eskimo.com Sent: Monday, January 08, 2007 3:20 AM Subject: Re: [Vo]: Optics question In reply to Hoyt A. Stearns Jr.'s message of Sat, 6 Jan 2007 17:41:40 -0700: Hi, [snip] In a digital light processing (DLP) display, a light source (soon to be a tri color laser) projects on an array of movable mirrors. The light for the dark parts of the image are sent to a beam dump. That seems wasteful. Is it possible to collect that light and re-introduce it into the primary source? Instead of using the mirrors to direct the beam to a beam dump, simply turn the laser off for a fraction of a second. This will require a change in the logic and electronics, but is much more efficient (instead of recovering the energy, it is simply not used in the first place). It also means that the mirrors can continue to scan the line, maintaining momentum. Then the mirrors need not be as easy to maneuver, which is technically simpler and cheaper to implement, as well as resulting in a more robust design that produces a better quality image. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
Re: [Vo]: Optics question
There is a misunderstanding of the nature of DLP technology. The active element is an array of tiny mirrors created by silicon machining techniques, one for each pixel. Each mirror can be tilted by a small angle under control from a TV signal. That tilt determines wihether the light falling on it goes to a location on the screen or to a dump. The average intensityof each pixel is determined by the fraction of time the mirror illuminates the screen. The individual mirrors do not scan, they only switch light to or away from one location on the screen. The optics, once fixed, are quite robust. The only variable is the lamp. which has finite life and must be changed. Mike Carrell --- In reply to Hoyt A. Stearns Jr.'s message of Sat, 6 Jan 2007 17:41:40 -0700: Hi, [snip] In a digital light processing (DLP) display, a light source (soon to be a tri color laser) projects on an array of movable mirrors. The light for the dark parts of the image are sent to a beam dump. That seems wasteful. Is it possible to collect that light and re-introduce it into the primary source? Instead of using the mirrors to direct the beam to a beam dump, simply turn the laser off for a fraction of a second. This will require a change in the logic and electronics, but is much more efficient (instead of recovering the energy, it is simply not used in the first place). It also means that the mirrors can continue to scan the line, maintaining momentum. Then the mirrors need not be as easy to maneuver, which is technically simpler and cheaper to implement, as well as resulting in a more robust design that produces a better quality image. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means. This Email has been scanned for all viruses by Medford Leas I.T. Department.
Re: [Vo]: Optics question
Mike Carrell wrote: There is a misunderstanding of the nature of DLP technology. The active element is an array of tiny mirrors created by silicon machining techniques, one for each pixel. Each mirror can be tilted by a small angle under control from a TV signal. That tilt determines wihether the light falling on it goes to a location on the screen or to a dump. The average intensityof each pixel is determined by the fraction of time the mirror illuminates the screen. The individual mirrors do not scan, they only switch light to or away from one location on the screen. The optics, once fixed, are quite robust. The only variable is the lamp. which has finite life and must be changed. Exactly right. About 10 years ago, when the practical application of DLP was in its infancy, I was asked to consult about methods of improving light usage in DLP systems. My suggestion, which sounds sophisticated, but is in fact very simple, was as follows: Each mirror facet, instead of being a plane mirror would be etched as a fresnel zone plate, the diffraction equivalent of a lens. At the focus of the zone plates would be a holographic optical element (HOE) that would represent a secondary pixel array much finer than the original mirror zone plate array. The light could then be directed to the proper section of the HOE to illuminate the pixels as needed. Hardly any light would be wasted except for losses due to having an extra element in the system. Naturally, an all black picture would still represent 100% light loss, but on the average, this system would require a much lower power lamp for the same image brightness. This sounds all very well and good, but the digital processing power necessary was not available at consumer prices at the time. As we all know, processor speed and power has increased geometrically in the last decade. I'm still waiting for that call-back. How may Rs in fat chance? M. ___ Join Excite! - http://www.excite.com The most personalized portal on the Web!
Re: [Vo]: Optics question
On 1/8/07, Mike Carrell [EMAIL PROTECTED] wrote: There is a misunderstanding of the nature of DLP technology. The active element is an array of tiny mirrors created by silicon machining techniques, one for each pixel. You forget the spinning light filter for RGB. Truly a rube goldberg technology: http://www.dlp.com/ Terry
Re: [Vo]: Optics question
In reply to Hoyt A. Stearns Jr.'s message of Sat, 6 Jan 2007 17:41:40 -0700: Hi, [snip] In a digital light processing (DLP) display, a light source (soon to be a tri color laser) projects on an array of movable mirrors. The light for the dark parts of the image are sent to a beam dump. That seems wasteful. Is it possible to collect that light and re-introduce it into the primary source? Instead of using the mirrors to direct the beam to a beam dump, simply turn the laser off for a fraction of a second. This will require a change in the logic and electronics, but is much more efficient (instead of recovering the energy, it is simply not used in the first place). It also means that the mirrors can continue to scan the line, maintaining momentum. Then the mirrors need not be as easy to maneuver, which is technically simpler and cheaper to implement, as well as resulting in a more robust design that produces a better quality image. Regards, Robin van Spaandonk http://users.bigpond.net.au/rvanspaa/ Competition provides the motivation, Cooperation provides the means.
[Vo]: Optics question
In a digital light processing (DLP) display, a light source (soon to be a tri color laser) projects on an array of movable mirrors. The light for the dark parts of the image are sent to a beam dump. That seems wasteful. Is it possible to collect that light and re-introduce it into the primary source? Hoyt Stearns Scottsdale, Arizona US http://HoytStearns.com
