Originally Posted by Ricketts223
Finally got a chance to experiment - huge improvement! I used a small paint roller and gently rolled the entire screen, which, I assume, changes the spacing between the actual lcd panel and the plastic diffusion layers beneath. Completely viewable now. I am happy with the fix but it isn't for everyone or the faint of heart.
But I agree, this thread should be closed and/or removed. It will only go downhill from here. Too many people need to have the last word.
I don't think that you managed to move the diffuser + BEF's; you have probably just introduced mechanical stress to the way pixels rotate to let through the light -> like hydraulic valve turns to control the fluid flow. You may have equalised the stress across the whole LCD panel - removed any bias that was there due to incorrect assembly, or bad shipment / transport…..
Diffuser is further back, BEF’s are immediately behind the LCD panel. BEF’s (brightness enhancing film sheets) are also known as lens sheets. The light-manipulation “sandwich” consists of 1 thick diffuser, and 1 or 2 thinner BEF’s. Diffuser is there to disperse the light evenly across its whole area. BEF’s have 2 basic functions:
1: to refract the photons multiple times until they are angled correctly to pass through the LCD panel at right angle – “straight through”. This technic optimises brightness and contrast AND, unfortunately, is the main reason why the viewing angles suffer. Many people believe that the viewing angles are purely the function of the LCD panel type used… this is wrong! If 1 BEF is used -> manufacturer can choose if horizontal OR vertical viewing angles will be affected (of course, vertical viewing angles are less noticeable...) If 2 BEF’s are used -> both viewing angle planes are affected equally.
2: to direct the photos (that can not be angled correctly) back towards the backlight source where they are virtually re-bounced of the white plastic reflector -> re-used and re-attempted at getting them to the right angle to pass through the LCD panel. This technique can save up to 30% in backlight photon generation costs – read: electricity.
The whole sandwich has to be assembled loose and be able to move freely between LCD panel and the backlight source; however, it has to be firmly AND correctly placed to REST on the bottom plastic holders, so that the “sandwich” does not get stuck between LCD panel and the TV metal frame during assembly OR during transport.
The whole backlight generation and its manipulation is so “basic” and trivial… with so many areas where things could go wrong…. it is amazing how good the LCD TV picture actually is…. CRT TV technology is much more elegant, precise and sophisticated… with the way electron beam can be controlled (even speeded-up on large flat CRT screens to obtain same peripheral speed across full width of perfectly flat CRT screen with single point of beam generation).... but picture tube size have limits, and then there’s a vacuum, residual magnetism.... weight… bulkiness.