[Display science knowledge] LCD technical parameters: contrast

For the monitor, it is very important to be able to display the picture clearly and vividly

If the displayed "black" is not black enough, and the "white" is not white enough

It is difficult to obtain a well-defined picture.

One of the parameters to measure the performance of the display is the contrast ratio.

Contrast refers to the ratio between the brightest white and the darkest black in the bright and dark areas of an image.

The larger the difference range, the greater the contrast, and the smaller the difference range, the smaller the contrast.

A good contrast ratio of 120:1 can easily display vivid and rich colors,

When the contrast ratio is as high as 300:1, each level of color can be supported.

The current mainstream LCD screen contrast ratio is generally at the level of 400:1 to 600:1, good ones can reach 1000:1 or even higher.

The higher the contrast, for black and white display,

The clearer the displayed characters and the sharper the graphic outline

For color display, the higher the color purity, the brighter and more realistic the image

High brightness contrast (left), low brightness contrast (right)

From the definition of contrast, there are two main ways to improve contrast

One is to increase the maximum brightness value of the display, and the other is to decrease the minimum brightness value.

That is, make the white ones whiter and the black ones blacker.

Affected by the characteristics of the liquid crystal, the liquid crystal display will have a certain degree of light leakage at the darkest time.

So even if it is adjusted to a pure black screen, the LCD display will still have some brightness.

A slight change in the darkest brightness will have a greater impact on the contrast.

This is a problem of the denominator and numerator. The smaller the numerator, the higher the contrast.