http://www.physorg.com/news6233.html
At current production the lamps for projection TV only lasts about 6 months depending on usage. At an expense of around $300. each I would think they could manufactor a lamp that would last a lot longer once the green laser is profected. I would love to have a large screen projection TV and not have to buy a new lamp twice a year.
what is needed is a small projector for small conf rooms. Even laptop may need not have a screen. A small white screen should be enough. THis allows larger views on wall at one's work desk.
What is also needed is low cost something like 50 USD. It may come as attachment thru USB Port or something like that.
What is also needed is low cost something like 50 USD. It may come as attachment thru USB Port or something like that.
I remember reading someplace that someone had produced a white LED that was so bright, it could be used as a projector lamp for projection TVs.
Since LED lifetimes are usually very long, I think the problem will solve itself sometime fairly soon. I hope so, as I have a projection TV, myself.
Haven't had the lamp burn out yet, and have used the TV a lot (most of the day) for over a year now.
Knock on wood...
Since LED lifetimes are usually very long, I think the problem will solve itself sometime fairly soon. I hope so, as I have a projection TV, myself.
Haven't had the lamp burn out yet, and have used the TV a lot (most of the day) for over a year now.
Knock on wood...
The reading on the white LED was from a story at this site. There shouldn't be any problem in carrying over the technology toward the projection TV. I ask, "Why should there?" and would love to see an answer.
a few years ago there was a story about a laser projector
R,G,B laser beams scan across the projector screen, CRT fashion, no lens or lamp required. Now what ever happened to that?
R,G,B laser beams scan across the projector screen, CRT fashion, no lens or lamp required. Now what ever happened to that?
I haven't heard or seen any follow up either dwk. Typical of brilliant ideas flashing the pan and never seen again. 
QUOTE
R,G,B laser beams scan across the projector screen, CRT fashion, no lens or lamp required.
Not that original of an idea, I hate to say.
The devil's in the details.
You need lasers powerful enough to compare with projector lamps, and a projector lamp costs about $600 for 1600Watts of power. So, take a wild guess how much 500W-class lasers cost? (I know of one that costs $200,000.)
Also, while you don't need lenses, you do need scanners, the things that drive mirrors back and forth very quickly, and they wear out. (The electron beam in a common non-HDTV tube makes one horizontal line every 63microseconds, IIRC. No scanners work that fast.)
The make great outdoor displays of closed-loop figures (like outlines of things), but light-shows and TV sets have much different standards.
And, incidentally, we have lasers of all colors, including ones the human eye can't see. You can buy a green laser pointer for $30 on eBay. Blue laser pointers cost about $300, last time I checked, but they exist. Neither are bright enough to project a big-screen TV image, though.
A 500W world class laser costs $200,000? Where did you see this beauty and place the price?
google "Sparkle Optics", visit their website. I used to work with Santanu Basu, I think I can talk him into giving me a good deal.
Thanks wcelliott for the information. 
QUOTE (wcelliott+Jun 14 2008, 12:51 PM)
You need lasers powerful enough to compare with projector lamps, and a projector lamp costs about $600 for 1600Watts of power. So, take a wild guess how much 500W-class lasers cost? (I know of one that costs $200,000.)
Hey, we don't want to blind anyone here... The whole point of laser projection is that you don't need a 1600 watt light source!
A projector lamp has a lower flux density due to the fact that the light is distributed across the entire screen all the time.
Not so for a laser projector - the entire intensity of each laser is concentrated on a single pixel at each point in time (persistence of vision does the rest), so you can get away with just using an ordinary cheap diode laser in a reasonably dark room.
A 1600 Watt laser would vaporise the screen pretty quickly...
Hey, we don't want to blind anyone here... The whole point of laser projection is that you don't need a 1600 watt light source!
A projector lamp has a lower flux density due to the fact that the light is distributed across the entire screen all the time.
Not so for a laser projector - the entire intensity of each laser is concentrated on a single pixel at each point in time (persistence of vision does the rest), so you can get away with just using an ordinary cheap diode laser in a reasonably dark room.
A 1600 Watt laser would vaporise the screen pretty quickly...
I've had similar thought dwk. Thanks for the input and does anyone disagree?
QUOTE
does anyone disagree?
Sorry, but I do.
TV images are produced in various ways these days, but they all break down images into red, green, and blue dots.
To match a big projection movie screen's brightness, you need a certain amount of red light, green light, and blue light to illuminate the whole screen at the same time.
If you raster-scan red, green, and blue lasers to replicate a movie image, the total amount of light will need to be equivalent.
Now, I did accidentally leave out a factor, namely that a black screen with a film projector is made by filtering-out all 1600Watts of light, while with the laser system, all three lasers would just be off (no power). But if you want to project a full-screen of all white, you'll need 1600W of laser power to do it. So the average laser power would be, maybe, half of 1600W (statistically), but you'd still need to size the system for the worst-case, which would be the white-screen, at 1600W of total laser power.
QUOTE (wcelliott+Jun 26 2008, 01:02 PM)
Now, I did accidentally leave out a factor, namely that a black screen with a film projector is made by filtering-out all 1600Watts of light, while with the laser system, all three lasers would just be off (no power). But if you want to project a full-screen of all white, you'll need 1600W of laser power to do it. So the average laser power would be, maybe, half of 1600W (statistically), but you'd still need to size the system for the worst-case, which would be the white-screen, at 1600W of total laser power.
I dare say that you left out at least one other factor.
The ground flux we receive from the sun is only around 1000 W/m^2 and typical projector screens do not generally tend to be (on order) twice as bright as direct sunlight. Note the conspicuous absence of people wearing sunglasses in cinemas, spontaneous projector-screen combustion, etc.
You also might like to consider the issue of light bulb efficiency. A typical incandescent bulb is only ~1% efficient in terms of light output. So the luminosity from a typical projector bulb is closer to 16W than 1600W.
Now assuming that the red, green and blue laser intensities contribute equally to produce white, what's 16/3? 5.3W. So you need three 5.3W lasers to produce comparable intensity to a 1600W projector bulb.
wcelliott, do you happen to know the price for 3x ~5.3W visible lasers? I'm guessing it's significantly cheaper than $200K.
I dare say that you left out at least one other factor.
The ground flux we receive from the sun is only around 1000 W/m^2 and typical projector screens do not generally tend to be (on order) twice as bright as direct sunlight. Note the conspicuous absence of people wearing sunglasses in cinemas, spontaneous projector-screen combustion, etc.
You also might like to consider the issue of light bulb efficiency. A typical incandescent bulb is only ~1% efficient in terms of light output. So the luminosity from a typical projector bulb is closer to 16W than 1600W.
Now assuming that the red, green and blue laser intensities contribute equally to produce white, what's 16/3? 5.3W. So you need three 5.3W lasers to produce comparable intensity to a 1600W projector bulb.
wcelliott, do you happen to know the price for 3x ~5.3W visible lasers? I'm guessing it's significantly cheaper than $200K.
QUOTE
I dare say that you left out at least one other factor.
You're right.
I'm an engineer, with 30 years' experience with systems of all sorts, a patent on high-energy laser optics cooling (#7,360,310), and one of my previous tasks this year was to build a Solar Simulator to test a solar-powered rocket engine my company is developing. We examined all the various available lamp options to generate sunlight, and decided on a 1600W Xenon Arc Lamp, like what's used in movie projectors. They're about 50% efficient.
My next job was helping to turn a white-paper of mine into a proposal for building a high-energy laser radar of my own design.
My current job is helping to design a solar-thermal electrical power plant, and I'm running a bit late to work, so I'll have to leave a few other factors out and end it here.
I also left out the efficiencies of the lasers.
The highest-efficiency lasers I know of are less than 50% (and those are IR, invisible to the human eye). The "Sparkle Lasers" link includes one visible laser that's 35% efficient (electric:beam power).
Green laser pointers are less efficient than that, because they actually start out as one type of laser (IR) that gets converted into another type of laser at twice the original frequency (the conversion is less than 20% efficient, and the original laser is 50% efficient).
In general, you can assume that a laser will be about 20% efficient, plus or minus 10%, but the shorter the wavelength, the lower the efficiency, in general.
The Defense Department is always funding research into increasing laser efficiencies by various means, so the situation will probably improve in the future, but I'd be surprised if visible lasers achieved greater than 50% efficiency in my lifetime.
My apologies if my prior post sounded snotty, but I wanted to avoid the usual bickering that happens in this and every other forum whenever people hold different opinions.
The highest-efficiency lasers I know of are less than 50% (and those are IR, invisible to the human eye). The "Sparkle Lasers" link includes one visible laser that's 35% efficient (electric:beam power).
Green laser pointers are less efficient than that, because they actually start out as one type of laser (IR) that gets converted into another type of laser at twice the original frequency (the conversion is less than 20% efficient, and the original laser is 50% efficient).
In general, you can assume that a laser will be about 20% efficient, plus or minus 10%, but the shorter the wavelength, the lower the efficiency, in general.
The Defense Department is always funding research into increasing laser efficiencies by various means, so the situation will probably improve in the future, but I'd be surprised if visible lasers achieved greater than 50% efficiency in my lifetime.
My apologies if my prior post sounded snotty, but I wanted to avoid the usual bickering that happens in this and every other forum whenever people hold different opinions.
Well, that settles that then, you obviously know what you're talking about.
If you get a chance though, you might just like to drop Mitsubishi Electric a line, just to let them know that their latest upcoming product (a rear projection DLP TV using R, G, B lasers instead of a bulb and filter wheel) is actually completely unviable:
http://en.wikipedia.org/wiki/Laser_tv
http://laser-tv.org/category/laser-tv-news/
http://www.lsrtv.com/
If you get a chance though, you might just like to drop Mitsubishi Electric a line, just to let them know that their latest upcoming product (a rear projection DLP TV using R, G, B lasers instead of a bulb and filter wheel) is actually completely unviable:
http://en.wikipedia.org/wiki/Laser_tv
http://laser-tv.org/category/laser-tv-news/
http://www.lsrtv.com/
QUOTE (wcelliott+Jun 27 2008, 12:12 AM)
a solar-powered rocket engine my company is developing.
Ion drive?
Ion drive?
QUOTE
QUOTE (wcelliott @ Jun 27 2008, 12:12 AM)
a solar-powered rocket engine my company is developing.
Ion drive?
a solar-powered rocket engine my company is developing.
Ion drive?
No, stored solar thermal energy to superheat a storable working fluid, conventional rocket beyond the fact that the energy source isn't chemical.
I never said lasers couldn't be made to work, I said they'd be more costly than conventional light sources for big screens, and specifically pointed out how movie theaters use $600 1600W Xenon Arc Lamps, which are 50% efficient at producing light from electricity, and 500W-class lasers are a lot more expensive and less efficient, all points which are *still* true.
QUOTE (wcelliott+Jun 28 2008, 07:40 PM)
I never said lasers couldn't be made to work, I said they'd be more costly than conventional light sources for big screens, and specifically pointed out how movie theaters use $600 1600W Xenon Arc Lamps, which are 50% efficient at producing light from electricity, and 500W-class lasers are a lot more expensive and less efficient, all points which are *still* true.
Perhaps I should draw your attention to the following report?
http://www.osti.gov/bridge/servlets/purl/7...able/761030.PDF
OK. I hope that clears things up.
As I said earlier, it all comes down to persistence of vision (let's just forget all about laser efficiencies, shall we? ).
Human retinal cells have a finite signal decay rate, so rather than requiring one huge consistent light source (= intensity of each pixel X number of pixels on screen), it's quite sufficient to illuminate each pixel at the required intensity individually, at a fraction of the power.
[For a typical screen resolution, and your figure of ~500W per laser for the whole screen: 1024x768=786432 pixels --> 500W / 786000 = ~.5 milliwatts per laser, so their figure of 0.15mW per laser seems pretty reasonable]
As long as the entire scan across the screen is completed within an acceptable fraction of the signal decay period of a human retinal cell (+ optic nerve lag, etc), the average human's natural detection apparatus is incapable of telling the difference.
I appreciate that such intricacies of human vision don't come into your line of work (and least of all solar energy transfer!), but I felt that it was worth pointing out - 'cause with the greatest possible respect, you seemed to be missing the wood for the trees back there!!
(I was of course wrong in terms of light bulb efficiencies though)
Perhaps I should draw your attention to the following report?
http://www.osti.gov/bridge/servlets/purl/7...able/761030.PDF
QUOTE
Abstract
Full color laser television has been demonstrated using a combination of three solid state
lasers with average power per laser of about 15 mw. The picture was illuminated with
wavelengths of red 635 mq green 532 nm and blue 473 nm these three wavelengths produce a
color triangle exceeding TV phosphors and movie film.
Full color laser television has been demonstrated using a combination of three solid state
lasers with average power per laser of about 15 mw. The picture was illuminated with
wavelengths of red 635 mq green 532 nm and blue 473 nm these three wavelengths produce a
color triangle exceeding TV phosphors and movie film.
OK. I hope that clears things up.
As I said earlier, it all comes down to persistence of vision (let's just forget all about laser efficiencies, shall we?
). Human retinal cells have a finite signal decay rate, so rather than requiring one huge consistent light source (= intensity of each pixel X number of pixels on screen), it's quite sufficient to illuminate each pixel at the required intensity individually, at a fraction of the power.
[For a typical screen resolution, and your figure of ~500W per laser for the whole screen: 1024x768=786432 pixels --> 500W / 786000 = ~.5 milliwatts per laser, so their figure of 0.15mW per laser seems pretty reasonable]
As long as the entire scan across the screen is completed within an acceptable fraction of the signal decay period of a human retinal cell (+ optic nerve lag, etc), the average human's natural detection apparatus is incapable of telling the difference.
I appreciate that such intricacies of human vision don't come into your line of work (and least of all solar energy transfer!), but I felt that it was worth pointing out - 'cause with the greatest possible respect, you seemed to be missing the wood for the trees back there!!
(I was of course wrong in terms of light bulb efficiencies though)
QUOTE (wcelliott+Jun 28 2008, 07:40 PM)
No, stored solar thermal energy to superheat a storable working fluid, conventional rocket beyond the fact that the energy source isn't chemical.
[OT] Wow! BubbleJet rocket propulsion! Wait till the guys at Canon get wind of this one!
Seriously, this does sound like a really really good idea.
[OT] Wow! BubbleJet rocket propulsion! Wait till the guys at Canon get wind of this one!
Seriously, this does sound like a really really good idea.
From your white-paper link:
You realize that if that isn't a typo, that means they need a motor to spin faster than 15 Million rotations per second...
Let me know if you find another link to a motor that runs that fast.
The other issue that you've overlooked when discussing the persistance of the retina is that it doesn't just persist with light, it persists with the dark interval, too. So the perceived brightness is the *average* power at a pixel. And 15mW per laser just ain't gonna cut it in terms of full-screen brightness in a home TV.
The paper never discussed how much brighter those 15mW lasers have to be before they can illuminate a regular-sized TV screen visible outside a cave at midnight.
QUOTE
The polygon needs to spin at the horizontal scan rate of 15750 kHz
You realize that if that isn't a typo, that means they need a motor to spin faster than 15 Million rotations per second...
Let me know if you find another link to a motor that runs that fast.
The other issue that you've overlooked when discussing the persistance of the retina is that it doesn't just persist with light, it persists with the dark interval, too. So the perceived brightness is the *average* power at a pixel. And 15mW per laser just ain't gonna cut it in terms of full-screen brightness in a home TV.
The paper never discussed how much brighter those 15mW lasers have to be before they can illuminate a regular-sized TV screen visible outside a cave at midnight.
QUOTE
that means they need a motor to spin faster than 15 Million rotations per second...
Let me know if you find another link to a motor that runs that fast.
Let me know if you find another link to a motor that runs that fast.
Ah yes, we'd all be in a hell of a mess if some bright spark hadn't invented gears and belt drives now wouldn't we?
(as an aside, Mitsubishi's version seems to use a DLP mirror array of some description the alleiviate this issue somewhat. And I hasten to add, Mitsubishi claim the price tag will be 'competitive with plasma and lcd', and have a fraction of the power consumption of power consumption of both these TV types)
QUOTE (->
| QUOTE |
| that means they need a motor to spin faster than 15 Million rotations per second... Let me know if you find another link to a motor that runs that fast. |
Ah yes, we'd all be in a hell of a mess if some bright spark hadn't invented gears and belt drives now wouldn't we?
(as an aside, Mitsubishi's version seems to use a DLP mirror array of some description the alleiviate this issue somewhat. And I hasten to add, Mitsubishi claim the price tag will be 'competitive with plasma and lcd', and have a fraction of the power consumption of power consumption of both these TV types)
The other issue that you've overlooked when discussing the persistance of the retina is that it doesn't just persist with light, it persists with the dark interval, too.
OK, now this is just getting ridiculous.
If Mitsubishi says it's planning on making a laser-DLP (backscreen projection) TV, then I'm sure they aren't blowing smoke.
They make lasers and they make TVs, so perhaps they've made some breakthrough in the cost of powerful-enough lasers to make the concept work.
I assure you, though, that they aren't talking about using 15mW lasers for the display. (Mitsubishi is one of Sparkle Laser's main competitors for 100W-class lasers.)
They make lasers and they make TVs, so perhaps they've made some breakthrough in the cost of powerful-enough lasers to make the concept work.
I assure you, though, that they aren't talking about using 15mW lasers for the display. (Mitsubishi is one of Sparkle Laser's main competitors for 100W-class lasers.)
This goes back to the viability of laser projection TV's and there usage. I agree with dwk this is quite possible.
I actually welcome the idea of Mitsubishi mass-manufacturing 100-watt class lasers, my guess is that the cost-drop (relative to the $200k 100-Watt lasers available from Sparkle Optics) is due to the amortization of engineering costs over the number of TVs they expect to sell.
I have a personal stake in welcoming this drop in 100-watt class lasers as I recently proposed to DARPA a laser radar, and one of the driving costs of the program was the $200k cost of the laser system. I hadn't received a quote from Mitsubishi, which has innovative ways to both pump an optical-fiber laser and get rid of the excess heat (from the innate inefficiency of the lasing medium).
So if they manage to pull this off, my hat's off to them, and I'll be happy that I can get decent-power lasers for a lot less than I'd expected to have to spend.
For what it's worth, when I first posted that the idea wasn't new, I meant that it was similar to an idea that I'd filled-out an "invention disclosure" form on back in 1978, for combat area "active camouflage", projecting a lot of false images of soldiers creeping-in on an enemy-held position, to "spoof" their nightvision gear (night combat) and overwhelm their defenses, decreasing the likelihood that our actual soldiers would be spotted amongst all the false-images of soldiers. The company's patent att'y didn't file for a patent for the idea, for his own reasons. (I still think it'd be a good idea.)
I have a personal stake in welcoming this drop in 100-watt class lasers as I recently proposed to DARPA a laser radar, and one of the driving costs of the program was the $200k cost of the laser system. I hadn't received a quote from Mitsubishi, which has innovative ways to both pump an optical-fiber laser and get rid of the excess heat (from the innate inefficiency of the lasing medium).
So if they manage to pull this off, my hat's off to them, and I'll be happy that I can get decent-power lasers for a lot less than I'd expected to have to spend.
For what it's worth, when I first posted that the idea wasn't new, I meant that it was similar to an idea that I'd filled-out an "invention disclosure" form on back in 1978, for combat area "active camouflage", projecting a lot of false images of soldiers creeping-in on an enemy-held position, to "spoof" their nightvision gear (night combat) and overwhelm their defenses, decreasing the likelihood that our actual soldiers would be spotted amongst all the false-images of soldiers. The company's patent att'y didn't file for a patent for the idea, for his own reasons. (I still think it'd be a good idea.)
Good luck in the personal stake you have in profiting from the laser technology, wcelliott.
The problem with working for defense contractors is that you sign-away your rights to file for patents on ideas you have while accepting their paychecks.
They didn't file a patent for the idea, but neither did I, and the concept of "active camouflage is now an old one, even for combat applications.
The proposal I wrote a couple month's back also won't yield me any personal profit, it'll just make the end customer happier. All I get is a paycheck (and sometimes a patent).
e.g., USPTO#7,310,360.
They didn't file a patent for the idea, but neither did I, and the concept of "active camouflage is now an old one, even for combat applications.
The proposal I wrote a couple month's back also won't yield me any personal profit, it'll just make the end customer happier. All I get is a paycheck (and sometimes a patent).
e.g., USPTO#7,310,360.
Better than nothing wcelliott. I understand how frustrating this must be to accept only the handout given to you through a paycheck.
I had, early-on in my career, submitted a lot of "invention disclosures" to the various companies I'd worked for, and got them all refused (some patented since by others) for reasons that didn't stand up to close scrutiny. My latest was on a power cell that simplified the production of electricity and oxygen for life support on manned space missions, and also had a fail-safe mode where it would produce heat and oxygen if the thing failed, so it could still provide life-support. It was rejected on the grounds that it was too complicated, and NASA wants to make things safer. I wrote the manager of the group that rejected the patent, pointing out that it *was* simpler and *was* safer, and he said he reviewed it and supported its rejection (without addressing any specific points).
Having had so many inventions rejected by the patent reviewers, I decided to go work for the group at a major aerospace company and see for myself what sort of process they use for judging the invention disclosures.
I first discovered that the people they select as reviewers are generally the dregs of the engineering community, along with the dregs of the patent lawyers, and they're both so lazy that fewer than half of the invention disclosures are even *read*, much less by someone with any interest in the ideas.
When I joined the department, a senior-level reviewer pulled me aside and showed me how they did it. If it isn't a dimensioned drawing (like for a machine shop) but a schematic "cartoon" (as he put it) associated with the concept, reject it. If it isn't from someone with a PhD, reject it. If it isn't being used on a current program, reject it. If it comes from company executive, approve it regardless. See how simple it is?
Mine were all "Quick Kills", because I knew that the patent office *doesn't* require dimensioned drawings (doesn't like them, certainly) so I'd provided "cartoons" that illustrate the concept as clearly as possible, I don't have a PhD, the ideas were too new to already be in use in a program (they'd be the basis for new programs), and I was never an executive at any of the companies, so none of mine were automatically approved.
It was enough to make me sick, how the inventions and inventors were handled.
Having had so many inventions rejected by the patent reviewers, I decided to go work for the group at a major aerospace company and see for myself what sort of process they use for judging the invention disclosures.
I first discovered that the people they select as reviewers are generally the dregs of the engineering community, along with the dregs of the patent lawyers, and they're both so lazy that fewer than half of the invention disclosures are even *read*, much less by someone with any interest in the ideas.
When I joined the department, a senior-level reviewer pulled me aside and showed me how they did it. If it isn't a dimensioned drawing (like for a machine shop) but a schematic "cartoon" (as he put it) associated with the concept, reject it. If it isn't from someone with a PhD, reject it. If it isn't being used on a current program, reject it. If it comes from company executive, approve it regardless. See how simple it is?
Mine were all "Quick Kills", because I knew that the patent office *doesn't* require dimensioned drawings (doesn't like them, certainly) so I'd provided "cartoons" that illustrate the concept as clearly as possible, I don't have a PhD, the ideas were too new to already be in use in a program (they'd be the basis for new programs), and I was never an executive at any of the companies, so none of mine were automatically approved.
It was enough to make me sick, how the inventions and inventors were handled.
The politics are dancing wcelliott. Too bad you probably had a 'tweak' of a couple of your inventions and someone received the patent. Nasty politics wcelliott as I read your post. 
I felt bad for the other inventors, too, but I always based my recommendations on the inherent value of the invention (and quickly p*ssed-off my boss in the process).
Better the word is out than silence is the thought process I see here. A very honorable man you are wcelliott. 
A very honorable man you are wcelliott.
Thanks for the kind words. (Don't see much of that around here.)
Your welcome.
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