RoadTest: Texas Instruments DLP® LightCrafter™
Evaluation Type: Evaluation Boards
Did you receive all parts the manufacturer stated would be included in the package?: True
What other parts do you consider comparable to this product?: in house development
What were the biggest problems encountered?: 1. The color is not uniform. Even with adjustment and cannot get the uniform colors to match color chart. 2. Light distance is not far enough for my application. 3. The delay time/jitter is too long for high-speed application. It is good for simple low speed video display.
I believe this module is a great one for those who want to display simple video. It is handy and does not require additional cooling. However, the module that I received had several drqwbacks. the first is red color uniformity. I had tried numerous times to calibrate and still not come out matching with my color chart. The second one is the delay time or jitter issue. this may not be an issue for people to do 3D display. However, it makes it unsuitable for sensitve application like PLL. the fhird issue is the display distant. for my application, it is not bright enough.
I understand your issues on proprietary designs, but I think I understand what you are trying to accomplish.
Actually you did answer the major question I had, which was about the color/spectral purity and stability of the device. I am curious if you have a defective unit or if the design is bad. I was looking to use this device as a spectral controlled illuminator, but if it cannot maintain the spectral lines, then I will need to look elsewhere. Hopefully a TI engineer will post some data or observations about their tests on the unit before it ships.
If you replace the LED's and get a more stable color output, I would be interested in your findings.
Also, any other observations you can make about the device would be welcome.
I take it they use the DLP to scan the illumination over the area they project?
Are they doing any dynamic focusing with the DLP? That might explain some of the jitter.
Meanwhile, I will look for your future updates.
Thanks for answering my post.
chin wong wrote:
thanks for suggustion. I had tried by pumping more current into the LED to increase the intensity.
You can't "pump" current into anything, current is drawn by the load. Make sure each LED is drawing the same amount of current, the voltage drop across each LED should be very close to the same. That is one reason why LED replacement bulbs are so expensive, because the LEDs must be matched to ensure consistent coloring.
thanks for suggustion. I had tried by pumping more current into the LED to increase the intensity. Adding an active cooling is simple but color shift is another thing. Unless I use a match LED pair, please let me know the technique to resolve the issue of color splite between multiple LEDs that emitting different light intensities and colors. You know LED would shift its color slightly under different current.
Our hi speed PLL is a proprietary design. I cannot reveal more in depth info w/o permission. The main point is the delay time and jitter which various as much as 100mS. That's too much for my design to overcome. The other issue is the color issue. I tried to calibrate the color based on std color chart.. Somehow the red color is off. One way to compensate for is by readjusting the LED current. then it gets into the intensity issue and color shift issue. That's why I spend a lot of time to cal/recal for color matching. Our PLL is very sensitive for color shift.
2. Light distance is not far enough for my application.
you can use more light if you add an active cooling system then you can use up to 40 lumen which could be enough
Could you provide more detail on your application and some more information on why you did not feel this device would not solve your problem?
If nothing else, could you give us a run down on the various features available and some visuals of the output? I know a lot of people were interested in this device, including myself, so I would like to see more information that would help me make a buy decisions.