LCD display principle and application

1. What is LCD?

(1) LCD (Liquid Crystal Display) referred to as liquid crystal.

(2) Liquid crystal is a kind of material, which has a characteristic that liquid crystal molecules can be rotated by electric signals, and the light transmission is affected when rotating, so we can use white light behind the entire liquid crystal panel (called backlight). ), the liquid crystal molecules can be selectively transmitted through different electrical signals. At this time, various colors are viewed in front of the liquid crystal panel, which is the LCD display.

(3) Passive illumination and active illumination. Some monitors (such as LED monitors, CRT monitors) themselves emit light called active light. Some (LCD) itself does not emit light and only transmits light. It needs the assistance of backlight to appear to be luminous, called passive illumination.

(4) LCD application fields: TV, computer display, mobile phone display, industrial display, etc.

Main related concepts of LCD display

1. pixel (pixel)

(1) The entire image is comprised of pixels, and the pixel is a display point.

2. pixel pitch (pitch)

(1) The pitch is the distance of the pixel center of two consecutive pixels.

(2) Pixel spacing will affect the optimal viewing distance of the screen. The pixel pitch is larger for long distance viewing, and the pixel pitch is small for close range viewing.

3. resolution (resolution)

(1) The number of pixels in the horizontal and vertical directions of the entire screen is referred to as the resolution.

(2) Screen size and resolution are irrelevant, like the size of the development board is seven inches.

(3) There is a correlation between screen size and resolution and pixel pitch.

4. clarity

(1) Clarity is a subjective concept. To put it plainly, people appear to feel clear and unclear.

(2) Objectively speaking, the resolution is given in the resolution and the pixel pitch.

(3) The definition is also determined by many other factors.

5. pixel depth (bits per pixel, referred to as bpm)

(1) How many bytes of data a pixel are described in a computer.

(2) The more data bits employed to represent a pixel in a computer, the more color, the finer the color of the pixel, and the deeper the color depth.

(3) Generally speaking, there are several kinds of pixel depths: 1 bit, 8 bits, 16 bits, 24 bits, and 32 bits.

Application

In order for the LCD to work, a mapping must be established between the Crystal screen and the video memory (the mapping is done by the CPU initialization the LCD controller).