hey, moxtek has a sample kit, it's got 2 pcs of the high-transmission stuff at about 1x1inch. if there were a way of getting all the light to go through that little space, you could use that.
although, i don't know if they make you buy the sample kit or not.
/andrew
although, i don't know if they make you buy the sample kit or not.
/andrew
if u had a small ark bulb u could do it before it goes through the condenser lens, maybe ? lol any ideas on that?
Trev
Trev
polarizing film
Hezz:
Good stuff. Read up a bunch on how little of our light makes it through the LCD!!!!
I'm thinking of a design where the lower polarizer on the lcd is removed. Then use a reflective polarizer under the bottom fresnel.This would drop LCD temps alot, I think.
Then have some mirrors down around the lamp to try to recover some of the reflected light from the polarizer and shove it through again.
Basically your idea except converted over to an OHP setup....
This is starting to get interesting.......
Hezz:
Good stuff. Read up a bunch on how little of our light makes it through the LCD!!!!
I'm thinking of a design where the lower polarizer on the lcd is removed. Then use a reflective polarizer under the bottom fresnel.This would drop LCD temps alot, I think.
Then have some mirrors down around the lamp to try to recover some of the reflected light from the polarizer and shove it through again.
Basically your idea except converted over to an OHP setup....
This is starting to get interesting.......
who's brave?
I forgot....
Does anyone have a dead panel to try to peel off the lower polarizer?
Maybe it can be reused in conjunction with a glass plate under the fresnel.....
I forgot....
Does anyone have a dead panel to try to peel off the lower polarizer?
Maybe it can be reused in conjunction with a glass plate under the fresnel.....
Ace3000_1,
Thanks for the tip. I will try it but some members have had success with this request and others have not. It couldn't hurt though.
Hezz.
Proto5,
Any progress you should make in this area of light polarizing and recycling for OHP would be welcome progress.
I would not recommend removing the polarizer from off of the back of LCD though as your panel might not work. It is better to have two polarizers than only one as film polarizers are not perfect and two would work better than one to keep heat out of the LCD. It is the non polarized light which builds up most of the heat in the LCD because the polarizing film converts the non polarized light into heat.
Because the light may not take a direct perpendicular path from the polarizing film into the LCD you want the original polarizing film to stay in as close contact with the LCD panel as possible. I would recommend mounting an additional reflective polarizer to a piece of glass and put it on top of the lower fresnel where your upper fresnel used to be. This will let the heat build up in the lower reflective polarizer to dissipate somewhat into the glass and the body of the OHP.
Hezz
Thanks for the tip. I will try it but some members have had success with this request and others have not. It couldn't hurt though.
Hezz.
Proto5,
Any progress you should make in this area of light polarizing and recycling for OHP would be welcome progress.
I would not recommend removing the polarizer from off of the back of LCD though as your panel might not work. It is better to have two polarizers than only one as film polarizers are not perfect and two would work better than one to keep heat out of the LCD. It is the non polarized light which builds up most of the heat in the LCD because the polarizing film converts the non polarized light into heat.
Because the light may not take a direct perpendicular path from the polarizing film into the LCD you want the original polarizing film to stay in as close contact with the LCD panel as possible. I would recommend mounting an additional reflective polarizer to a piece of glass and put it on top of the lower fresnel where your upper fresnel used to be. This will let the heat build up in the lower reflective polarizer to dissipate somewhat into the glass and the body of the OHP.
Hezz
polarizer
Hezz:
Trust me I'll use a cheapo LCD to test with!
I'd be concerned that adding another polarizer w/o removing one would suck up more light than we could gain!
What if we removed BOTH polarizers and put one reflective one under the bottom fresnel, and another on the mirror after the OHP objective lens...........can we get a first surface mirror with polarizer film already attached?
Just speculating and stirring the pot......😉
Hezz:
Trust me I'll use a cheapo LCD to test with!
I'd be concerned that adding another polarizer w/o removing one would suck up more light than we could gain!
What if we removed BOTH polarizers and put one reflective one under the bottom fresnel, and another on the mirror after the OHP objective lens...........can we get a first surface mirror with polarizer film already attached?
Just speculating and stirring the pot......😉
Proto 5
hey proto and crew ive got an idea that may make a small difference to an ohp too, im not using a ohp so i cant test it but this idea has got to do somthing in the way of saving light. Ok in the inside of the projector have u seen how much light is in the darn box that gets reflected to the sides and wasted on the dull paint in there? ok well the idea is is to use the aluminium that is very reflective that is used in the office fluro's as a type of reflector and diffuser at the same time, they use it mainly to get more out of the fluro cos its round and puts out more light when reflected at diff angles, why not cover the inside of the ohp with it? that way the light that is waisted in the normally flat paint or grey paint atleast gets reflected to the top cos most ohp's have a tapper from bottom to top, i would cover the flour too and ofcourse not cover the vent holes. U coukld try this with double sided tape to test it first and if it's a goer glue it, anyway here is just a site on halogens just for some info and have a look at the light output these buggers have.
Trev
hey proto and crew ive got an idea that may make a small difference to an ohp too, im not using a ohp so i cant test it but this idea has got to do somthing in the way of saving light. Ok in the inside of the projector have u seen how much light is in the darn box that gets reflected to the sides and wasted on the dull paint in there? ok well the idea is is to use the aluminium that is very reflective that is used in the office fluro's as a type of reflector and diffuser at the same time, they use it mainly to get more out of the fluro cos its round and puts out more light when reflected at diff angles, why not cover the inside of the ohp with it? that way the light that is waisted in the normally flat paint or grey paint atleast gets reflected to the top cos most ohp's have a tapper from bottom to top, i would cover the flour too and ofcourse not cover the vent holes. U coukld try this with double sided tape to test it first and if it's a goer glue it, anyway here is just a site on halogens just for some info and have a look at the light output these buggers have.
Trev
Sorry to bust in on this discussion But are you suggesting to use the Bulbs in the above link, as a replacement for peoples OHP bulbs? or am I missing something?
nope but just as a resorce, people can use what they want, basically just look at the lumens those halogens put out, not bad at all, shame about the colour temp, and the temp
video freak
video freak is this bulb bright enough for u? this would fit into a ohp and its only 45cm long by 1.1million lumens 12000w lol
http://catalog.gelighting.com/cgi-bin/gx.cgi/AppLogic+FTContentServer?
maybe ill use that for my 6inch lcd (yeah right)
Trev
video freak is this bulb bright enough for u? this would fit into a ohp and its only 45cm long by 1.1million lumens 12000w lol
http://catalog.gelighting.com/cgi-bin/gx.cgi/AppLogic+FTContentServer?
maybe ill use that for my 6inch lcd (yeah right)
Trev
Proto5,
The polarizer on the fresnel beneath the LCD yes but I don't understand your reasoning for the one on the mirror after the objective lens. All of the polarization needs to be done before the light enters the LCD. Because of the way the molucules in the LCD shutters interact with light any light entering the LCD must be polarized. Light which is not polarized is disregarded by the LCD.
I am unable to percieve any possible gain from putting a polarizer after the LCD unless there is some kind of excessive glare coming off of the LCD screen.
Check out these screen shots of the polarizing recycler without the parabolic reflector and light bulb.
Hezz
The polarizer on the fresnel beneath the LCD yes but I don't understand your reasoning for the one on the mirror after the objective lens. All of the polarization needs to be done before the light enters the LCD. Because of the way the molucules in the LCD shutters interact with light any light entering the LCD must be polarized. Light which is not polarized is disregarded by the LCD.
I am unable to percieve any possible gain from putting a polarizer after the LCD unless there is some kind of excessive glare coming off of the LCD screen.
Check out these screen shots of the polarizing recycler without the parabolic reflector and light bulb.
Hezz
Attachments
lcd construction
Hezz:
LCDs have 2 polarizers, one on top & one underneath-they have to to work.
An analysis of the structure of a TFT/LCD briefly described above reveals that it is an optically very inefficient system. For example, in a 12.1-in. SVGA panel, currently in wide use for notebook computers, a mere 10% of the total light output from the backlight eventually reaches the viewer's eye; the rest is lost along the way. There are three major absorbers. The first is the dichroic polarizer attached to the TFT glass. As the unpolarized output from the backlight passes through the polarizer, its intensity is halved owing to complete absorption of one polarization component as well as some absorption of the other component. The second absorber is the black matrix on the TFT glass, an absorptive substance coated on the non-pixel area of the TFT glass. The amount of loss by the black matrix is proportionate to the non-pixel area, or the complement of the aperture ratio of the TFT glass. Since the aperture ratios of 12.1-in. SVGA panels range around 70%, the loss is approximately 30%. The third absorber is the color filter. Although various alternative filter schemes are being developed [1-4], the method currently in general use is pigment dispersion [5]. Each pigment-dispersed pixel on the color filter transmits light in its specific wavelength range and absorbs the rest. The color-filter absorption is approximately 70%. Finally, the combination of these three major factors yields the above-mentioned low figure of 10%.
Hezz:
LCDs have 2 polarizers, one on top & one underneath-they have to to work.
An analysis of the structure of a TFT/LCD briefly described above reveals that it is an optically very inefficient system. For example, in a 12.1-in. SVGA panel, currently in wide use for notebook computers, a mere 10% of the total light output from the backlight eventually reaches the viewer's eye; the rest is lost along the way. There are three major absorbers. The first is the dichroic polarizer attached to the TFT glass. As the unpolarized output from the backlight passes through the polarizer, its intensity is halved owing to complete absorption of one polarization component as well as some absorption of the other component. The second absorber is the black matrix on the TFT glass, an absorptive substance coated on the non-pixel area of the TFT glass. The amount of loss by the black matrix is proportionate to the non-pixel area, or the complement of the aperture ratio of the TFT glass. Since the aperture ratios of 12.1-in. SVGA panels range around 70%, the loss is approximately 30%. The third absorber is the color filter. Although various alternative filter schemes are being developed [1-4], the method currently in general use is pigment dispersion [5]. Each pigment-dispersed pixel on the color filter transmits light in its specific wavelength range and absorbs the rest. The color-filter absorption is approximately 70%. Finally, the combination of these three major factors yields the above-mentioned low figure of 10%.
Attachments
Proto 5
thats why those who use the 3 grey scale lcd's are brighter, if u used 3 colour lcd's at 10% light each of the main source light u would get in total 30% of the main source out, not bad its 3 times as much and 3 times as much work too lol as for the grey scale if u got 20% - 30% light out of each lcd u would get 60% - 90% of the source light out but thats not counting the colour filters u will need that would absorb probally nearly half for each lcd so in terms it would probally work out the same if u used 3 colopur lcd's or 3 grey scale with colour filters, why dont they just dont use colour lcd's u might ask? ok have a look at the price's! for these small high res lcd's and maybe there is a diff only small but a gain using colour filters over colour lcd's as u are only using one colour on each lcd than rather 3 on each lcd so there has got to be a gain just in that.
Trev
thats why those who use the 3 grey scale lcd's are brighter, if u used 3 colour lcd's at 10% light each of the main source light u would get in total 30% of the main source out, not bad its 3 times as much and 3 times as much work too lol as for the grey scale if u got 20% - 30% light out of each lcd u would get 60% - 90% of the source light out but thats not counting the colour filters u will need that would absorb probally nearly half for each lcd so in terms it would probally work out the same if u used 3 colopur lcd's or 3 grey scale with colour filters, why dont they just dont use colour lcd's u might ask? ok have a look at the price's! for these small high res lcd's and maybe there is a diff only small but a gain using colour filters over colour lcd's as u are only using one colour on each lcd than rather 3 on each lcd so there has got to be a gain just in that.
Trev
hezz
hezz i wouldnt go playing with the polarisers on lcd's cos they would already be optimised for light output, if they could make them brighter they would so they would use cheaper less powerful backlights, ive read a fair bit into the case and the german and french and spanish did a study on making new films for the lcds to be brighter, they have made a film but i guess the time will tell when it will be in place and used in future lcd's and that study and new film was created so the use of cheaper and cooler lcd backlights can be used, one thing that might be different from the lcd's we are using and the projector lcd's is the use of uv protection so the lcd doesnt get discoulered from the light source uv rays, even though u can use a filter a filter wont cut all of the uv resaulting in discoulourisation of the lcd over time.
Trev
hezz i wouldnt go playing with the polarisers on lcd's cos they would already be optimised for light output, if they could make them brighter they would so they would use cheaper less powerful backlights, ive read a fair bit into the case and the german and french and spanish did a study on making new films for the lcds to be brighter, they have made a film but i guess the time will tell when it will be in place and used in future lcd's and that study and new film was created so the use of cheaper and cooler lcd backlights can be used, one thing that might be different from the lcd's we are using and the projector lcd's is the use of uv protection so the lcd doesnt get discoulered from the light source uv rays, even though u can use a filter a filter wont cut all of the uv resaulting in discoulourisation of the lcd over time.
Trev
Ace3000 and Proto5,
Sounds like you guys have been doing some homework. Now come to think of it they do use a polarizer on the front side of the LCD but I am not sure what it does.
Ace, I have no intention of removing the LCD polarizers myself when I get my system up and running.
The brightness enhancement films from 3M are not polarizers they are thin plastic sheets with micro prism's that help to focus the light more effectively on the LCD. They are often used in modern LCD computer displays.
Others on the site have tried placing a reflective polarizer before the LCD in addition to the LCD polarizer and though it decreases light output a small amount it appears to increase contrast and definition.
I would be interested to hear what part the post polarizer does in the system.
Hezz
Sounds like you guys have been doing some homework. Now come to think of it they do use a polarizer on the front side of the LCD but I am not sure what it does.
Ace, I have no intention of removing the LCD polarizers myself when I get my system up and running.
The brightness enhancement films from 3M are not polarizers they are thin plastic sheets with micro prism's that help to focus the light more effectively on the LCD. They are often used in modern LCD computer displays.
Others on the site have tried placing a reflective polarizer before the LCD in addition to the LCD polarizer and though it decreases light output a small amount it appears to increase contrast and definition.
I would be interested to hear what part the post polarizer does in the system.
Hezz
Yes, if the system if to be long term stable it must have the UV rays filtered as the will eventually damage all of the LCD components. Metal Halide puts out lots of IF and UV rays.
They also make some UV and IF blocking polarizers but I do not know which companies manufacture them.
Hezz
They also make some UV and IF blocking polarizers but I do not know which companies manufacture them.
Hezz
hezz
howdy hezz yeah your right about the mh putting out alot of uv, manny new types of mh are out now and manny have uv block filter built in, how much they block im not sure but i do know they block uv-b and uv-c, as for the polarised light for lcd's and the films lcd's use and what they do there are a few threads around with posts on that, dont ask me what they are cos remebering a post in the huge forum is like trying to find a needle in a hay stack lol basically from my understanding the lcd crystal twists when a current is aplied so it is like a valve in a way but to light, not with the polarising i think on the back of the lcd it is horizontal, and on the front it is vertical im not sure if thats correct but thats just from memory and also what that does is help the opening and closing of light per pixel, if this info is not correct correct me somone lol but thats my understanding.
cheers Trev
howdy hezz yeah your right about the mh putting out alot of uv, manny new types of mh are out now and manny have uv block filter built in, how much they block im not sure but i do know they block uv-b and uv-c, as for the polarised light for lcd's and the films lcd's use and what they do there are a few threads around with posts on that, dont ask me what they are cos remebering a post in the huge forum is like trying to find a needle in a hay stack lol basically from my understanding the lcd crystal twists when a current is aplied so it is like a valve in a way but to light, not with the polarising i think on the back of the lcd it is horizontal, and on the front it is vertical im not sure if thats correct but thats just from memory and also what that does is help the opening and closing of light per pixel, if this info is not correct correct me somone lol but thats my understanding.
cheers Trev
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