[Display Knowledge Popularization] LCD Technical Parameters: Transmittance

Since the liquid crystal panel itself does not emit light, it needs to rely on the light source provided by the backlight source to achieve brightness display.

Therefore, the transmittance (Transmittance) has become an important optical parameter of the LCD panel.

Its size directly affects the power consumption of the entire display.

If the transmittance is high, the brightness requirements of the backlight can be reduced, and the power consumption of the overall module will be reduced.

There are many factors that affect the transmittance of the display panel. In the light propagation path emitted by the light source, the various components that play the role of the light transmission medium will have an impact on the transmittance.

When light is emitted from the backlight, it will pass through the polarizer, glass, liquid crystal, color filter, etc. in sequence.

Suppose the penetration rate of each part is as follows:

Polarizing plate 50% (because it only allows polarized light waves in one direction to pass),

95% glass (need to calculate the upper and lower two pieces),

LCD 95%

The aperture ratio is 50% (the effective light transmission area is only half),

Color filter 27% (assuming that the material itself has a transmittance of 80%, but because the filter itself is painted with color, only the light waves of that color can pass. For the three primary colors of RGB, only one of the three can be allowed It passes, so only one-third of the brightness is left. So the total can only pass 80%*33%=27%.)

Calculated based on the above transmittance, only 6% of the light emitted from the backlight will remain.

At present, the main method of increasing the transmittance is to increase the transmittance of the material and reduce the loss of light, and on the other hand, to increase the aperture ratio of the pixel in the panel setting.