LCD pixels

LCD pixels

1. Pixel

The entire image is composed of individual pixels, and the pixel is a display point. Pixels are the most basic elements that make up an image, or the smallest unit that can be controlled in the display. The entire image is composed of many pixels. Pixels can be individually controlled, or controlled to be bright or not (monochrome screen), or to control their brightness (for example, bright 50%, 35%, so called gray screen, the previous black and white TV), or control it Display a certain color (this is our most commonly used color display). Summary: Pixels are very important, the entire display image is composed of individual pixels. We want to display an image on the monitor, which is to discretize the image into dots, and then the color of each dot corresponds to the pixels of the monitor.

2. Pixel pitch (pitch)

Pitch is the distance between the pixel centers of two consecutive pixels. Normal pixels are square, so the horizontal pitch is the same as the vertical pitch. But there are also differences. The pixel pitch will affect the optimal viewing distance of the screen. Larger pixel pitch is suitable for long-distance viewing, and small pixel pitch is suitable for close-up viewing.

3. Resolution

The number of pixels in the horizontal and vertical directions of the entire screen is called the resolution. For example, the screen used by the X210 development board is 1024X600. The screen size has nothing to do with the resolution, like the screen size of the development board is 7 inches (the pure screen diagonal size is 7 inches). There is a correlation between screen size and resolution and pixel pitch.

4. Clarity

Clarity is a subjective concept and a subjective judgment of the human eye on the display effect. That is, people seem to feel clear and unclear. Objectively speaking, the definition is determined by the resolution and pixel pitch. In general, when the screen size is fixed, the higher the resolution, the clearer, the lower the resolution, the less clear; the smaller the screen size is, the clearer, the larger the less clear. Clarity is also determined by many other factors.

5. Pixel depth (bits per pixel, bpp for short)

The color of a pixel is described by how many bytes of data in the computer. The computer uses binary bits to represent the data of a pixel. The more data bits used to represent a pixel, the richer and finer the color value of this pixel, and the deeper the color depth. Generally speaking, there are several pixel depths: 1-bit, 8-bit, 16-bit, 24-bit, and 32-bit.

6. Driver & Controller

The analog electrical signal of the liquid crystal molecules and the control signal (digital signal) of the driver come from its own digital interface, which is the external interface of the LCD screen. The LCD controller is generally integrated in the SoC, and it is responsible for providing digital signals for controlling pixel display to the remote LCD driver through the digital interface. The key to the LCD controller lies in the timing. It must communicate with the LCD driver according to a certain timing; the LCD controller is controlled by the SoC, and the SoC will take pixel data from the memory to the LCD controller and finally to the LCD driver.