Quote:
Originally Posted by
action_jackson 
Here are a few possible reasons that manufacturers are not setting the pulse rates higher.
2. Pulse rate may effect lumen output. There may be a sweet spot with these LEDs. It is up to the projector manufacturer to come up with fastest pulse rate, while not sacrificing lumen output.
I'm pretty sure I read the same article you did relating pulse rate to perceived brightness. However, in the article the pulse rate was
very low yielding something like a 20hz refresh rate...which would produce significant flicker. This ideal is outside the minimum refresh rate for a display of 60hz, so I don't think this approach is being used here. Here is the article:
http://www.ledweekly.com/2008-03/technology/5033.htmlQuote:
Originally Posted by
Bsims2719 
There must be an artifact created from running the DLP chip faster. I can remember many years back that there was a manufacturer that let you choose (setting in the menu) between a faster or slower wheel speed. Now the question is why. Why would you ever want to run slower if it's capable of running faster.
I remember reading something that if the color wheel speed and DLP chip are sampling too fast, this can result in visible dithering (dithering should not be noticeable). Some of the older 720p DLPs you could actually see a sort of "tiling" or banding effect in movies with fast motion.
This may have been because the DLP chip was not quite fast enough to keep up with the color wheel, and during a scene with fast motion, your visual processing is faster, so you happen to see the dithering that you ordinarily wouldn't.
Quote:
Originally Posted by
action_jackson 
3. The speed of the DLP chip itself is a limiting factor. It is not capable of keeping up with the speed of the LEDs. I believe it should be able to go much faster than what we are seeing with the Qumi.
You have a good point. It is a possibility these new pico DLP chips are not fast enough for the LEDs to be pulsed faster without visible dithering. I guess we'll just have to wait for the Optoma, Viewsonic, or Acer to see if there is any variation.