Acording to this link:
http://cgi.ebay.com/Low-price-Brand...NameZWDVWQQrdZ1QQcmdZViewItem#ShippingPayment
it has over 100k pixels so its no worse than psone. Infact it should be more than the psone no. I am a bit confused if this pixel count is combined Red Green and Blue or per color. Another words is the native rez 480x234 ?
Equal to the lilliput 7 inch standard not the xga or vga version.
This would seem a better option than the psone since I could probably use 35mm slide projector objective.
http://cgi.ebay.com/Low-price-Brand...NameZWDVWQQrdZ1QQcmdZViewItem#ShippingPayment
it has over 100k pixels so its no worse than psone. Infact it should be more than the psone no. I am a bit confused if this pixel count is combined Red Green and Blue or per color. Another words is the native rez 480x234 ?
Equal to the lilliput 7 inch standard not the xga or vga version.
This would seem a better option than the psone since I could probably use 35mm slide projector objective.
slide projector lenses
Sure, if you have an LCD that is the size of a 35 mm slide, then a slide projector lens would work fine. The light engine might not be bright enough, since color LCDs lose much more light than a color slide.
One problem with tiny LCDs is that the same amount of light has to go through a 2.5" LCD as a 15" LCD to get the same size and brightness image on the screen. The LCD color filters and polarizers will absorb the same percentage of the light for either size (around 80% of it!). That means the 2.5" LCD gets 36 times more energy per square inch than the 15" LCD! You will really have to blast it with a cool air stream to keep it from melting.
Commercial projectors use tiny LCDs, but those LCDs don't have color filters or polarizers so they hardly absorb any energy at all. All they do is twist the polarity. The color filters and polarizers are some distance from the LCDs, and are made from heat resistant materials.
Sure, if you have an LCD that is the size of a 35 mm slide, then a slide projector lens would work fine. The light engine might not be bright enough, since color LCDs lose much more light than a color slide.
One problem with tiny LCDs is that the same amount of light has to go through a 2.5" LCD as a 15" LCD to get the same size and brightness image on the screen. The LCD color filters and polarizers will absorb the same percentage of the light for either size (around 80% of it!). That means the 2.5" LCD gets 36 times more energy per square inch than the 15" LCD! You will really have to blast it with a cool air stream to keep it from melting.
Commercial projectors use tiny LCDs, but those LCDs don't have color filters or polarizers so they hardly absorb any energy at all. All they do is twist the polarity. The color filters and polarizers are some distance from the LCDs, and are made from heat resistant materials.
but a 2.5 inch lcd is larger than a 35mm slide. Will it still work with the slide projector lenses. Another words the lenses are designed for the viewing angle of a 35mm slide but is it possible they are designed to accept just a little larger angle of view say for a 60mm slide or 2.5 inches roughly
So in your opinion all resolution being equal you would choose a larger lcd say the playstation one.
So in your opinion all resolution being equal you would choose a larger lcd say the playstation one.
What cooling method do you recomend then. Lets says a 12cm fan on either side of the lcd. One pushing in the other exausting or would just the 12cm exhaust do it
cooling a tiny LCD
Lots of airflow, doesn't matter if you push or pull the air as long as all the hot air ends up outside of the projector without being recirculated. The other critical thing would be to use a real dichroic hot mirror to remove most of the IR before it gets to the LCD.
A slide projector lens might work for a 2.5" LCD. Try an experiment with some transparency film to find out: Use an ink jet or laser printer to print some tiny text all over the film. Then cut out a piece of it and frame it with some cardboard, so it gives you a 2.5" diagonal "slide". Then use a spotlight to project the slide's image through the slide projector lens. Use the lens-to-screen distance that your projector would use. You will see if the whole slide image gets through the lens, and gets focussed evenly.
Lots of airflow, doesn't matter if you push or pull the air as long as all the hot air ends up outside of the projector without being recirculated. The other critical thing would be to use a real dichroic hot mirror to remove most of the IR before it gets to the LCD.
A slide projector lens might work for a 2.5" LCD. Try an experiment with some transparency film to find out: Use an ink jet or laser printer to print some tiny text all over the film. Then cut out a piece of it and frame it with some cardboard, so it gives you a 2.5" diagonal "slide". Then use a spotlight to project the slide's image through the slide projector lens. Use the lens-to-screen distance that your projector would use. You will see if the whole slide image gets through the lens, and gets focussed evenly.
Thank for your help but I think this lcd here only has 112k /3 pixels or 37,000 pixels much much less than the psone.
Unless I can find a higher res one to at least match the psone I am going to abandon the 2.5 inch lcd projector.
http://cgi.ebay.com/Low-price-Brand...NameZWDVWQQrdZ1QQcmdZViewItem#ShippingPayment
Unless I can find a higher res one to at least match the psone I am going to abandon the 2.5 inch lcd projector.
http://cgi.ebay.com/Low-price-Brand...NameZWDVWQQrdZ1QQcmdZViewItem#ShippingPayment
Question for Guy,
Hi,
You mentioned in this thread that the LCD panels we use in monitors have "color filters and polarizers" are these built into the LCD ?..in other words is there any way we could remove some of the filters to increase light throughput ?
If answer is impossible, do you know if you or me can buy small LCD panels that don't have the color filters and polarizers built in ?
Im thinking small LCD's for use in an old CRT projector setup one LCD for each color.
Thanks in advance
Hi,
You mentioned in this thread that the LCD panels we use in monitors have "color filters and polarizers" are these built into the LCD ?..in other words is there any way we could remove some of the filters to increase light throughput ?
If answer is impossible, do you know if you or me can buy small LCD panels that don't have the color filters and polarizers built in ?
Im thinking small LCD's for use in an old CRT projector setup one LCD for each color.
Thanks in advance
filters and polarizers
Yes, those are built into the color LCD displays. I don't think you could remove them without damaging the LCD part.
I have been thinking about building a system like you are proposing, using three small monochrome LCDs. These should have much lower loss, and run cooler, since each LCD would get light with the right polarization and color to begin with.
I have looked for high performance monochrome LCDs for a while, and I have not found any with good contrast ratio, high resolution, and quick response time. So all I would get is a pretty bad projector, with a very bright image!
Using the 3 lens approach could be very cheap, since you could use CRT lenses (ie. around $15 each), and no fancy beam splitter/combiner optics. But you would have to re-converge the three color images any time you moved the projector.
Yes, those are built into the color LCD displays. I don't think you could remove them without damaging the LCD part.
I have been thinking about building a system like you are proposing, using three small monochrome LCDs. These should have much lower loss, and run cooler, since each LCD would get light with the right polarization and color to begin with.
I have looked for high performance monochrome LCDs for a while, and I have not found any with good contrast ratio, high resolution, and quick response time. So all I would get is a pretty bad projector, with a very bright image!
Using the 3 lens approach could be very cheap, since you could use CRT lenses (ie. around $15 each), and no fancy beam splitter/combiner optics. But you would have to re-converge the three color images any time you moved the projector.
Guy,
thanks for your reply
I was sure that the psone had removable polarising sheets, just thought other LCD's might have them as well.
Id thought Id seen a thread on this subject..but I couldnt find it .may have been another forum.
thanks for your reply
I was sure that the psone had removable polarising sheets, just thought other LCD's might have them as well.
Id thought Id seen a thread on this subject..but I couldnt find it .may have been another forum.
The thread is on lumenlab !
At last I found where Id seen someone trying to remove anti glare/polarizing films from an LCD Panel...Lumenlab, it's still in testing phase but it looks quite promising, with a big increase in light throughput.
That's not he end of the thread or story..but it is very interesting nonetheless and a very informative read.
Cheers
At last I found where Id seen someone trying to remove anti glare/polarizing films from an LCD Panel...Lumenlab, it's still in testing phase but it looks quite promising, with a big increase in light throughput.
That's not he end of the thread or story..but it is very interesting nonetheless and a very informative read.
Cheers
2.5" LCD
Here is the same size LCD with 330000 pixel, and its cheap.
http://cgi.ebay.com/ebaymotors/2-5-...ewItemQQcategoryZ38650QQitemZ8004307962QQrdZ1
Here is the same size LCD with 330000 pixel, and its cheap.
http://cgi.ebay.com/ebaymotors/2-5-...ewItemQQcategoryZ38650QQitemZ8004307962QQrdZ1
330000 pixels
Somebody should get one at that price. I rather doubt the 330000 pixel claim. That would be much higher than you would need for such a tiny display showing video. Most non-technical ads for small TVs and monitors for your car overstate the number of pixels by counting each subpixel. So they count one RGB pixel as 3.
If you see a value for the pixel size, and it is exactly square (or close to square), then it is probably real. You can calculate the true native resolution: You just divide the horizontal and vertical dimensions by the pixel size.
Somebody should get one at that price. I rather doubt the 330000 pixel claim. That would be much higher than you would need for such a tiny display showing video. Most non-technical ads for small TVs and monitors for your car overstate the number of pixels by counting each subpixel. So they count one RGB pixel as 3.
If you see a value for the pixel size, and it is exactly square (or close to square), then it is probably real. You can calculate the true native resolution: You just divide the horizontal and vertical dimensions by the pixel size.
notice it does not specify dot or pixel resolution. And there is a difference. Looked around and could not find any in 2.5 inch at such high native rez.
Sample Pricing. And the color ones are VGA, 640x480 pix. A 6'' VGA Lilli will output the same result, but without the need for dry ice as cooling 🙂.
if we got 3 of the mono ones, and a wavelength beamsplitter. we could build small projectors with a 1024x786 res, as long as you find a way to remove the heat, ir/uv glass?, there shouldn't be a problem.
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