What determines the contrast ratio in an Lcd Tv

Question

Is it the brightness of the lamp (ie) more brightness means more contrast ratio or ist it something else

Answer 1

Contrast ratio is (surprise!) a ratio of the brightest part of a display to the darkest. The brightness is indeed controlled by the lamp, but the darkest dark depends on a number of factors, like

- screen reflectance

- room light level

- how much internal light scattering goes on inside the TV. For example, if you put a max intensity white square in the middle of the screen, some of the light will go sideways, some will bounce off the screen surface and end up in the dark areas of the screen.

All this unwanted light in areas that are supposed to be dark reduces the contrast ratio. The best TVs go to great lengths to control this scattered light, often know as non-image forming light or flare, just like in cameras.