Originally Posted by DB2
Brightness is the issue right now. So far they've only been able to achieve 250 lumens with a projector the size of the old three gun CRT's.
That sounds like info from the early 2000s....
If you look at the Phlatlight technology (thanks Ohlson!
You'll see that they already have 16:9 (12mm^2 chip area) single LED chips blasting out 875 lumens for RED, 2100 lumens for GREEN and 400 lumens for BLUE.
Wavelengths are: 626nm RED, 528nm GREEN, 463nm BLUE.
In order to get D6500k out of the above wavelegths we need the following mix:
43.1% RED, 33.5% GREEN, 23.4% BLUE
So, let's take the dimmest (BLUE) LED and work backwards:
400lm (BLUE) at 23.4% means that we'll need
737lm (RED) for 43.1% and
573lm (GREEN) at 33.5% to get D65
If you look at the spec, we can safely overdrive BLUE to 600lm (50% overdrive) and still be in the safe/ comfortable region for both RED and GREEN.
If we redo our calculations we have:
600lm (BLUE - OVERDRIVEN) at 23.4% means that we'll need
1,105lm (RED) for 43.1% and
860lm (GREEN) at 33.5% to get D65
Now, add to that the various advantages that LEDs bring:
- Dynamic Iris Operation
- 80,000 hour halflife
- Higher Efficiency (lm/W)
- Lower thermal load - smaller heatsinks - simpler/smaller power supply
- No colorwheel (for DLP)
- Infinite contrast
- Asynchronous operation (any color can be on or off)
- Elimination of refresh artifacts
and we have a winner.
Now, back to the numbers, a single chip DLP system has a light conversion efficiency of about 15% (filters, colorwheels, light path losses, lamp inefficiencies etc. etc)
No doubt, an LED illuminated 1-DLP system would have a better efficiency than that but never better than the theoretical maximum of 33%.
Say, a good number would be 25% efficiency.
So, from the above numbers we get....
a 640 lumen projector!
Seriously though, it is doable, but obviously, there are issues implementing it or we would have it already...
By the end of 2009, I'll bet we'll have a 1,000 lumen >100,000:1 CR projector.
Anybody willing to take me on?