LED display technology from the early 1980s monochrome display, to the late 80s two- color display , and then to the mid-1990s the three primary colors ( full color ) display , until today, we have extensive areas of flat panel display discuss multi -color ( greater than three color ) processing technology. chroma processing technology led display color wavelength selection from the most basic to the deployment of white color temperature , and then to improve color reproduction and color space conversion for processing and to improve the quality of color uniformity processed until today we are in order to expand the color gamut reproduces more natural color and multi- color taken ( more than three primary colors ) processing . Wide range of color processing technology permeates the history of the development of LED display , LED display which become comprehensive discipline in one of the core technology .
All kinds of color processing technology
1, the primary color wavelength selection
LED display in all walks of life has a very wide range of applications , and in different application areas of LED color wavelengths have different requirements , the LED color wavelength selection is to get some good visual effects , some people in order to comply habits, and some of them are industry standards , national standards or international standards. For example, full-color LED display on the green tube color wavelength selection ; early we generally choose a wavelength of 570nm yellow-green LED, although
Low cost, but the color gamut of the display is small, poor color reproduction , brightness is low. When the selected wavelength of 525nm pure green tube , the display color gamut expanded nearly doubled , and the color reproduction is greatly improved, greatly improves the display of visual effects. As another example, the securities market display, people usually accustomed red rose with green fell , but with the yellow flat plate . In the transport sector is set by the strict requirements of the national standards prevailing blue and green bands represent the red band is forbidden line . Thus, the primary color wavelength selection is an important element of the LED display .
2 , white color coordinates the deployment of
White color coordinates deployment of full-color LED display is the most basic technologies. But in the mid- 1990s , due to the lack of industry standards and basic testing methods, usually just rely on the human eye , the feel sure white color coordinates , causing severe color cast and white color temperature of randomness. With the promulgation of industry standards and testing means complete, many manufacturers began to regulate full color matching process . But there are still some manufacturers due to lack of matching theoretical guidance , often at the expense of some of the color of gray levels to deploy one hundred color coordinates , the overall performance is not improved .
3 , color uniformity processing .
LED display color uniformity issue has long been plagued by a major problem in the industry is generally believed that the LED brightness uniformity single point calibration can be performed to improve the brightness uniformity. And chroma uniformity can not be corrected only by the LED color coordinates for segmentation and filtering to improve .
As people increasingly high demand for LED display , LED color coordinates only to be broken down and screening has been unable to meet critical eye on the integrated display correction processing, the color uniformity improvement is achievable the .
We found that even if the same file is an international brand , there are a large wavelength LED bias and color saturation bias , and the deviation range greatly exceeds the human eye to distinguish green color threshold Thus, chromaticity uniformity correction is important significance .
4, the color reproduction process
Chunlan, pure green LED 's birth, so full-color LED display with its wide color gamut , high brightness, sought after by the industry . However, since the red, green and blue LED 's color coordinates with PAL system TV RGB chromaticity coordinates of a large deviation ( see Table 1 ) , making the full-color LED color reproduction is poor. Especially in the performance of the person's skin color , the visual presence of obvious bias. Thus, the color reduction processing technology came into being. In this I recommend two color reduction processing methods :
First: the three primary colors red, green and blue LED for color coordinate space conversion , the LED TVs with PAL system between the trichromatic color coordinates as close as possible , thus greatly improving the LED display color reproduction . However, this method significantly reduced color gamut LED display so that the screen color saturation dropped significantly.
Second : Only the most sensitive to the human eye color gamut appropriate corrections ; while the other eye is not sensitive enough gamut reduced as little as possible the original color saturation. This process can be color fidelity and color saturation strike a balance between .