What is a color filter (CF)

Color filter (CF)

If you look at the LCD panel with a magnifying glass, you will find what it looks like in the picture below. We know that red, blue and green are the so-called three primary colors. In other words, using these three colors, you can mix a variety of different colors. Many flat panel displays use this principle to display color. We divide the three RGB colors into three independent points, each with different grayscale changes, and then use the adjacent three RGB display points as a basic unit of display, which is pixel. That pixel can have different color changes. Then for a display screen that requires a resolution of 1024 * 768, as long as the composition of this flat panel display is 1024 * 768 pixels, this screen can be displayed correctly. In the figure, the black part between each RGB point is called Blackmatrix. It is mainly used to cover parts that do not intend to transmit light. For example, some ITO traces, or Cr / Al traces, or TFT parts. Therefore, we can see in the figure that each bright spot of RGB is not a rectangle. There is also a part hidden by the black matrix in the upper left corner. This black missing part is the location of the TFT.

The figure below shows the arrangement of common color filters. Stripe (stripe) is most commonly used in OA products, that is, our common notebook computers, or desktop computers and so on. Why should this application be arranged in a strip? The reason is that most of the current software is a windowed interface. In other words, the screen content we see is composed of a large number of boxes of different sizes. The arrangement of the strips just makes the edges of these boxes look more straight, without a straight line. , It looks like it has burrs or jaggedness. But if it is applied to AV products, it will be different. Because TV signals are mostly characters, the lines of the characters are not straight, and their outlines are mostly irregular curves. Therefore, at the beginning, the AV products used mosaic arrangement (or diagonal arrangement). However, most recent AV products have been improved to use a triangular arrangement (or delta arrangement). In addition to the above arrangement, there is another arrangement, called square arrangement. It differs from the previous ones in that it does not use three points as a pixel, but four points as a pixel. The four points combine to form a square.