or Connect
New Posts  All Forums:

Posts by xrox

Ah, I took your meaning as the magnitude drop remains fixed. A percent drop makes more sense. Still not sure why it is needed if the power threshold remains the same.
The bright showroom problem was due to the diffuse reflections washing out contrast on PDP. As you point out the real problem is brightness, irrelevant of ambient light. When you put a display that is up to 5 times brighter than PDP beside it, the PDP will look dull in any ambient light.
Sounds like something is lost in translation here. Why on earth would a PDP require a fixed ABL when the primary purpose is to limit power? That makes absolutely no sense.
The ABL in PDP is no different than that of OLED or CRT. The peak brightness vs APL is varied in a way to try and keep the average brightness unchanged and thus the power unchanged. Turning down the contrast lowers the peak brightness. At some point it reaches a level below the ABL threshold. Same thing happens in a Plasma but at a much lower threshold.Efficiency and lifetime determine the strength of the ABL. Primarily PDP ABL was aggressive due to poor...
Aside from the internal glass reflections dispersion that all displays will have there are technology specific causes like CRT electron backscattering. I had a paper on this at one point but can't seem to find it. From what I remember OLED potentially can be the best at blooming/light leakage depending on design, Local dimming LCD is by far the worst for obvious reasons. CRT as discussed was also very bad. In both cases the blacks literally float with APL. PDP also...
A good chunk of CRT floating black was due to electron backscattering.
I checked the intellectual property on this topic and there is a good chance you are correct. Unlike the statements in that article about tracking usage through signal processing (which is known) the Ignis IP suggests a dedicated measurement circuit on each pixel. This may be novel (hence IP) but I'm not sure what is in the actual product they are marketing.
Ignis tech looks like a simple voltage compensation via signal processing. Time and/or current density is probably tracked from the signal processing step and the compensated voltages are calculated. No measurement is taken AFAIK. That would be way too expensive and complicated. But I may be wrong. http://www.oled-info.com/ignis-demonstrates-their-maxlife-external-compensation-technology Uniformity compensation of the backplane issues is much more difficult.
I can only imagine that "burn-in" or "pixel wear" compensation is done via signal monitoring and pre-programmed look-up tables. No need for pixel measuring circuits IIRC. Non-uniformities originating in the TFT is another story. Compensation circuits are needed and are costly. This is all from my memory from a few years ago so things may have changed.
I would argue that non-uniformities are inherent in any pixel based display type including plasma. However, PDP to my eye, has always been solidly better than LC in this regard to the point where I do not detect it with the visible eye.On the other hand I would consider visible mura the strongest and most offensive in LC based displays and is only enhanced due to the viewing angle problems. There are so many causes for mura in LC displays I don't see the problem ever...
New Posts  All Forums: