1. 3 +2 multi-color color processing methods:
In recent years, in the field of flat panel display keen to discuss 3 +3 multi-color display (red, green, blue plus yellow, blue, purple), to expand the color gamut, reproduce a more rich natural color. So, led display can achieve 3 +3 multi-color display?
We know that in the visible range, yellow and blue for the monochromatic light, we have a high saturation of the yellow, cyan LED. And purple for the complex color light, single-chip purple LED is not there. Although we can not achieve red, green, blue plus yellow, blue, purple 3 +3 multi-color led display. However, the study of red, green, blue plus yellow, green 3 +2 multi-color led display is feasible. Because of the large amount of high saturation of yellow and cyan in nature; therefore, the study is of some value.
In the current variety of television standards, the video source is only red, green and blue three primary colors, and no yellow and blue two colors. So, display terminal yellow, green two primary colors how to drive?
In fact, in determining the yellow and green two primary color drive strength; we follow the following three principles:
1, in improving the color saturation at the same time, shall not change the color;
2, increase the yellow and green two primary colors in order to expand the color gamut, thereby enhancing the color saturation. While the overall brightness value can not be changed;
3, to D65 as the center; to RYGCB color gamut as the endpoint, in the color gamut within the scope of linear expansion.
Under the guidance of the above three principles; according to the law of gravity center, we can find 3 +2 multi-color color processing methods. However, in order to truly achieve 3 +2 multi-color full color, we have to overcome the yellow, blue LED brightness is insufficient; cost increases and other difficulties, is currently limited to theoretical discussion.
Second, the color reduction processing:
Pure blue, pure green LED was born, so that full color LED display with its wide range of color gamut, high brightness sought after by the industry. However, due to the red, green and blue LED color coordinates and PAL TV red, green and blue color coordinates have a greater deviation (see Table 1), making the full color of the LED color reproduction is poor. Especially in the performance of human skin color, the visual there is a more obvious deviation. As a result, color
reproduction technology came into being. In this I recommend two ways to restore the color:
1, the red, green and blue three-color LED color coordinate space transformation, so that LED and PAL TV between the three primary colors as close as possible, thus greatly improving the color reproduction of the led display. However, the method significantly reduced the color gamut of the led display range, so that the screen color saturation dropped significantly.
2, only the most sensitive to the human eye color gamut to be properly corrected; and other human eye is not sensitive to the color gamut as little as possible to reduce the original color saturation. This can be balanced between color reproduction and color saturation.
Third, the choice of primary color wavelength:
Led display in the people with the requirements of the LED display is getting higher and higher, only the LED color coordinates of the breakdown and screening has been unable to meet people picky eyes, the display screen for comprehensive correction, the chromaticity uniformity Improvements are achievable.
We found that even the first international brand of the same brand of LED there is a large wavelength deviation and color saturation deviation, and the deviation range greatly exceeded the human eye on the green color difference identification threshold Therefore, the chromaticity uniformity correction is important meaningful.
In the CIE1931 chromaticity diagram, according to the law of gravity center, we found that: in the G range (abcd) any point of green mixing a certain percentage of red and blue, you can mix the color coordinates of the color line to adjust the line cR and The intersection of the straight line dB.
Although the chromaticity uniformity can be greatly improved. However, the corrected color saturation is significantly reduced. At the same time, the use of red and blue to correct the green color uniformity of another premise is the same pixel within the red, green and blue three kinds of LED as much as possible using a centralized distribution makes the red, green and blue color mixing distance as close as possible in order to achieve better Effect. The current industry is usually used in the LED evenly distributed method will give color uniformity correction to bring chaos. In addition, tens of thousands of red, green and blue LED color coordinate measurement work is how to start is a very difficult problem. We gave a hint.
Fourth, the color uniformity treatment:
Led display color uniformity problem has always been a major problem plagued the industry, generally believed that the brightness of the LED can be a single point of correction, to improve the brightness uniformity. And the chromaticity is not uniform can not be corrected, only through the LED color coordinates of the breakdown and screening to improve.