good ideas LI !
let us know how you get on at your other thread
money money money...never enough of the damn stuff !
🙂
matt
let us know how you get on at your other thread
money money money...never enough of the damn stuff !
🙂
matt
throwit said:
There are basically 4 LED elements in 1 housing, so yes.
In my latest setup, I am using both the 4chips leds and some narrow viewing angle LEDs. The combination of both of these helps to sharpen the picture.
Narrow-----------------Narrow
-------------4chips--------------
Narrow-----------------Narrow
I am now using around 110 4chips, and 150 of the narrow viewing angle.
I also found that the direction you place the led ( : . . ) will actually change the sharpness of the pixels as well. I am placing the narrow angle LEDs up and down : and the 4chips sideways . . .
I'll let you all know if I change again.
I'v also thought of a way to light evenly. I have some 3/4 inch plexiglass that a local hockey rink threw out. If I was to cut 1 inch strips of this, and stack them across the back of the LCD, I could then put the LED board behind and light it. I havent messed with this idea at all yet, but might in the future.
Is this possible????
Forgive me guys for I don't know what I'm doing...just thought it may work. Issue for light spotting on screen "might" be resolved.
100 led flashlight
Forgive me guys for I don't know what I'm doing...just thought it may work. Issue for light spotting on screen "might" be resolved.
An externally hosted image should be here but it was not working when we last tested it.
100 led flashlight
sorry Cordie, i can't help much with that, i'm not sure anyone else will be able to either 'cos your question could do with elaborating on
davidcw has found this company called luminus...
luminus
luminus products
some interesting stuff going on there
matt
davidcw has found this company called luminus...
luminus
luminus products
some interesting stuff going on there
matt
Attachments
Man, there's some good stuff going on here! Have to come here more often again!
I was looking at the LED spot light diagram posted by Cordie. Good idea, but won't work like you think it would. First, the focal point for the fresnel is exactly behind the lens (not off to the side). Aside from that, I've read fresnels have a useful angle of about 30 degrees. Anything more than that and the light gets scattered / useless.
But branching off of that idea, how about a prism? Take 3 light sources (all whites or R, G, and B) and place them at the appropriate "input" of the prism. Place the prism's "output" at the focal length of the fresnel. This could give you approx 3x the brightness.
I was looking at the LED spot light diagram posted by Cordie. Good idea, but won't work like you think it would. First, the focal point for the fresnel is exactly behind the lens (not off to the side). Aside from that, I've read fresnels have a useful angle of about 30 degrees. Anything more than that and the light gets scattered / useless.
But branching off of that idea, how about a prism? Take 3 light sources (all whites or R, G, and B) and place them at the appropriate "input" of the prism. Place the prism's "output" at the focal length of the fresnel. This could give you approx 3x the brightness.
Whoa cool Idea superdave.
I agree theres lots of cool stuff going on, Ive been away too long also 🙂.
glad to see you still at it throwit, Im heading back to the western world earlier than originally planned so I will be building my first led array sometime next month.
I agree theres lots of cool stuff going on, Ive been away too long also 🙂.
glad to see you still at it throwit, Im heading back to the western world earlier than originally planned so I will be building my first led array sometime next month.
Thanks stelleg151. The prism idea isn't anything new. The concept is used on higher end projectors. But I think it could be a good way to control the coloring of the final image and you should be able to put 3 times the amount of LEDs into the same light path. Just a theory. 🙂
Hi there,
it would be great if the retrofitting of LEDs in a commercial projector would turn out in a success. It's all about running costs and convenience (size, quality). I think actual leds are capable of making 100lumens to the projection screen, and that's not a bad figure if the result is compact, good picture quality, low noise and consumption, coupled with basically no need for replacement. That's the major turn down of commercial units.
About the route to be taken I find using LEDs of the three primary colours the best choice. They can even sit directly behind each screen, with the polarizers in between, thus dumping all those mirrors. That may make collimation easier. But careful with those tiny 3 LCDs and the quadro prism, I suspect the arrangement is very sensitive to misalignments.
The quadro prism is a very interesting optical piece. I am not sure how it works though, how it manages to superimpose the 3 images. If each prism would only let pass towards the lens and reflect it the otherwa,y it would do, but is that it? It would be like a light valve, and I'm not sure they exist. Or is the principle related to different wavelengths and/or refraction indexes?
I found a formula for translating those pesky mcd and beam angle to actual lumen output of the led. You may find it of use:
2*pi*sin b*(1-cos b)* i
b=half the beam angle
i=rated intensity in cd
Actually the lumen output is limited by this value, but in most cases 80% of it should be quite accurate with the useful lumen output.
For example, the leds on ebay with 30deg and 150000mcd give a lm output of 8.3lm at best, more likely 6.5 lm. Not bad vs their size and power.
I have a RPTV lens myself, and I am in the process of finding a good small TFT (hard to find, any suggestions, VGA 5-6"?) using the computer CRT meanwhile, as image source!
it would be great if the retrofitting of LEDs in a commercial projector would turn out in a success. It's all about running costs and convenience (size, quality). I think actual leds are capable of making 100lumens to the projection screen, and that's not a bad figure if the result is compact, good picture quality, low noise and consumption, coupled with basically no need for replacement. That's the major turn down of commercial units.
About the route to be taken I find using LEDs of the three primary colours the best choice. They can even sit directly behind each screen, with the polarizers in between, thus dumping all those mirrors. That may make collimation easier. But careful with those tiny 3 LCDs and the quadro prism, I suspect the arrangement is very sensitive to misalignments.
The quadro prism is a very interesting optical piece. I am not sure how it works though, how it manages to superimpose the 3 images. If each prism would only let pass towards the lens and reflect it the otherwa,y it would do, but is that it? It would be like a light valve, and I'm not sure they exist. Or is the principle related to different wavelengths and/or refraction indexes?
I found a formula for translating those pesky mcd and beam angle to actual lumen output of the led. You may find it of use:
2*pi*sin b*(1-cos b)* i
b=half the beam angle
i=rated intensity in cd
Actually the lumen output is limited by this value, but in most cases 80% of it should be quite accurate with the useful lumen output.
For example, the leds on ebay with 30deg and 150000mcd give a lm output of 8.3lm at best, more likely 6.5 lm. Not bad vs their size and power.
I have a RPTV lens myself, and I am in the process of finding a good small TFT (hard to find, any suggestions, VGA 5-6"?) using the computer CRT meanwhile, as image source!
something you all must see, if you already havent, http://www.lumileds.com/products/family.cfm?familyId=5
this has really high powered led's you have to call for price but i think that they are about 10 bucks a led array, do you think those could work?
this has really high powered led's you have to call for price but i think that they are about 10 bucks a led array, do you think those could work?
The biggest problem with high powered LED's is the higher fade rate they endure thoughout their life span. I see this happen in Cinema equipment all the time and LED fade is pretty much what killed Sony's SDDS digital sound system. Also the reflector it will require to obtain even light will be dificult if not impossible to design. I doubt that direct lighting of the LCD panels will be adaquate. Any array of LED's is going to have very uneven areas between the LED's. This is easy to see when looking at the video output of a SONY SDDS CCD camera or a Dolby Digital film reader camera..... Lots of spikes in the waveform from all the dead spots between the LED's in the arrays.
Also, your LED's will generate a fair amount of heat that has to be removed to be able to get any decent life span out of them!!
Mark
Also, your LED's will generate a fair amount of heat that has to be removed to be able to get any decent life span out of them!!
Mark
but these led's are now used in a projector http://www.mitsubishi-presentations.com/products/projectors/PK10.html
even though this one uses not as high of power led's it is the same company and it says that they run cooler and have a longer life span than the normal bulbs
even though this one uses not as high of power led's it is the same company and it says that they run cooler and have a longer life span than the normal bulbs
RGB leds behind 3LCDs
They actually did just that: http://www.handtops.com/forum/1606/10//LED_Projectors_by_Mitsubishi_Samsung_an.html
Notice the leds aren't very energy efficient.
Sony is also said to have developed a special screen, black to natural light but white to RGB, making day viewing feasible.
They actually did just that: http://www.handtops.com/forum/1606/10//LED_Projectors_by_Mitsubishi_Samsung_an.html
Notice the leds aren't very energy efficient.
Sony is also said to have developed a special screen, black to natural light but white to RGB, making day viewing feasible.
Leds promise much
Although current leds are less economical than discharge lamps it looks like in the near future it will be the other way: a manufacturer demonstrated a white LED with 131lm/W!
http://www.cree.com/press/press_detail.asp?i=1150834953712
Some >1000cd/m2 lcds and ready made led backlights
http://www.litemax.com.tw/tec_led_e.htm
On the other hand I can't find a small tft panel with enough resolution for a good price. I found a relatively cheap brand new 3LCD projector with good resolution though, and if retrofitting leds isn't very difficult it would be a nice "complete kit" (Viewsonic PJ452, XGA, 600$). 3LCD seems to lose less light vs DLP. So how hard is it to make a commercial projector work without its proprietary lamp? throwit, any progress?
Although current leds are less economical than discharge lamps it looks like in the near future it will be the other way: a manufacturer demonstrated a white LED with 131lm/W!
http://www.cree.com/press/press_detail.asp?i=1150834953712
Some >1000cd/m2 lcds and ready made led backlights
http://www.litemax.com.tw/tec_led_e.htm
On the other hand I can't find a small tft panel with enough resolution for a good price. I found a relatively cheap brand new 3LCD projector with good resolution though, and if retrofitting leds isn't very difficult it would be a nice "complete kit" (Viewsonic PJ452, XGA, 600$). 3LCD seems to lose less light vs DLP. So how hard is it to make a commercial projector work without its proprietary lamp? throwit, any progress?
hi zzonbi
depends on if you're thick as i am !
the answer was on this website for only a year or so before i clocked it !...have a read of this (mainly post 512 onwards)
good luck, i'm here and there if i can help anyone in my limited way 🙂
matt
depends on if you're thick as i am !
the answer was on this website for only a year or so before i clocked it !...have a read of this (mainly post 512 onwards)
good luck, i'm here and there if i can help anyone in my limited way 🙂
matt
Thanks, there's so much information here sometimes it's easier to just ask😉
After reading those last posts it is still unclear if the shortcircuit trick worked for your model as well.
Modding a commercial proj seems increasingly appealing, albeit not so true to diy, I found a 515$ brand new model, only WXGA though. If they get cheaper still, there will truly remain just the hardcore diy-ers to take the build from scratch route. But I guess modding one isn't total betrayal.
After reading those last posts it is still unclear if the shortcircuit trick worked for your model as well.
Modding a commercial proj seems increasingly appealing, albeit not so true to diy, I found a 515$ brand new model, only WXGA though. If they get cheaper still, there will truly remain just the hardcore diy-ers to take the build from scratch route. But I guess modding one isn't total betrayal.
i really think it's working !!!
an hour and a half now, and seemingly normal lp250 operation, except for the lack of heat and light !
shining a bright torch in the light engine opening reveals a murky but changing image on my palm in front of the lens
😀 😀 😀
the two terminals marked by OzOne in red, or the corresponding wires need to be linked together, then the lamp psu/ballast can be removed and not needed
an hour and a half now, and seemingly normal lp250 operation, except for the lack of heat and light !
shining a bright torch in the light engine opening reveals a murky but changing image on my palm in front of the lens
😀 😀 😀
the two terminals marked by OzOne in red, or the corresponding wires need to be linked together, then the lamp psu/ballast can be removed and not needed
Attachments
I don't know if this company has been mentioned, yet, but I posted this information on the Big Screen Forums.
Take a look at this site, Goldeneye Inc.
For those that don't RTFA 😀, here's what it says:
In explaining their technology (there isn't much), their "Recycling Optics" pdf says, in part,
Seems to hold a lot of promise.
Too bad there isn't anything on the shelf to purchase, as they don't have anything to show for it, yet. But, at least, they and others are working on the problem.
regards,
MAJ
Take a look at this site, Goldeneye Inc.
For those that don't RTFA 😀, here's what it says:
In explaining their technology (there isn't much), their "Recycling Optics" pdf says, in part,
Seems to hold a lot of promise.
Too bad there isn't anything on the shelf to purchase, as they don't have anything to show for it, yet. But, at least, they and others are working on the problem.
regards,
MAJ
hi OzOnE
this is the reply to your post at ywhs' thread !
...those leds arrived some time ago, but as with many things ebay, the description and the reality aren't comparable - there's no way they're as bright as suggested, but a luxeon should really give out in the region of 100lm per led, so say you get 1000lm +/- per 40mmx40mm, and you remove unnecessary obstacles in the light path, and achieve 40% efficiency (up from 15% to 25%), you've got yourself a 400lm@lens pj there mister !
if you look at led:yes you can page 3 and led:yes you can page 4 , you'll see the kinda solutions i've thought of, i had considered a 'reverse eye' like the goldeneye in the beginning, but i know of a better way (which i'd prefer to keep under my hat) but i don't think it'll be necessary to go as far as that...time'll tell
price and availability may be an issue, but these are interesting, very interesting
🙂
this is the reply to your post at ywhs' thread !
...those leds arrived some time ago, but as with many things ebay, the description and the reality aren't comparable - there's no way they're as bright as suggested, but a luxeon should really give out in the region of 100lm per led, so say you get 1000lm +/- per 40mmx40mm, and you remove unnecessary obstacles in the light path, and achieve 40% efficiency (up from 15% to 25%), you've got yourself a 400lm@lens pj there mister !
if you look at led:yes you can page 3 and led:yes you can page 4 , you'll see the kinda solutions i've thought of, i had considered a 'reverse eye' like the goldeneye in the beginning, but i know of a better way (which i'd prefer to keep under my hat) but i don't think it'll be necessary to go as far as that...time'll tell
price and availability may be an issue, but these are interesting, very interesting
🙂
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