Originally Posted by cah95046
My understanding is:
1) The LCD matrix blocks or passes light depending on the voltage applied to the pixel. 1a) Almost all of the passed light is emitted from the face of the panels. 1b) Some of the passed light leaks to adjacent pixels before being emitted from the face of the panel.
2) The light emitted from the face of the panel can be: 2a) forced to pass through a narrow slit (mostly blocked), 2b) concentrated (focused) in a particular direction or 2c) widely dispersed.
Some claim 1b is the source of blooming in a FALD. I don't buy this. On my FALD tv, if I turn off FALD, there is no blooming. Blooming is the result of the eye being able to see a greater dynamic range than the native CR of the LCD, not pixel to pixel light leakage. Dark pixels in a brightly lit zone look lighter than dark pixels in a dark zone.
Relative intensifies observed by the eye: 2b >> 2c ~ 2a
Disagree? What am I missing?
Yes, halo/bloom is caused by native contrast of the KCD panel not being sufficient to bring the black level of 'off' pixels down below the perceptible threshold.
The only 3 ways to reduce halo/bloom on a FALD LED/LCD are to:
-improve native contrast ratio of the LCD panel (~7000:1 is about the max).
-reduce the size of local dimming zones (by using more).
-improve the lical dimming algorithm so that each and every zone is only 'lit up' to the minimum luminance required to emit whatever are the brightest pixels within that zone (especially those zones also containing black / off pixels...).
All of that being said, this is true only for on-axis. One of the ways VA LCDs have delivered poor off-axis viewing is poorer black levels and increased halo/bloom when viewed off-axis. These off-axis photons are probably 'leaking' or otherwise the result of dispersion that corresponds to your 1b above.
So off-axis halo/bloom may not be strictly dependant on native contrast ratio only... (and if Samsung has succeeded to reduce/eliminate off-axis halo/bloom by adding these additional layers, that is fantastic).