In 2000, LCD liquid crystal displays replaced CRT screens one after another. This screen is referred to as LCD, and its full name is Liquid Crystal Display.
1. How to display black and white LCD screen
layer it
The basic LCD screen is divided into 2 layers: a layer of LED backlight and many pieces of LCD
Liquid Crystals: A Wonder Material
The material of liquid crystal is amazing. This transparent material will become opaque when electrified .
Its principle is that some opaque small pieces are vertical first, so that we can only see its almost non-existent sides
When these sheets are flipped over to the front, we see that most of the sheets block the clear liquid crystal:
Connect many pieces of liquid crystals to form a single liquid crystal screen.
2. No matter how simple the screen is, it needs a graphics card
When you see the graphics card, you will definitely think that this is unnecessary, but each CPU has a graphics card integrated. Graphics cards are very important to our LCD screens.
Generally, a conventional screen has 5 million pixels (1920*1080), but will you have 5 million pins on a CPU to control these pixels? Obviously can't do it.
The graphics card, to put it bluntly, is to publish the processed content on the display screen.
Let's take the simplest 1602 display and take a look at its graphics card.
This screen has 16 display areas per row, and there are 2 such areas to get its name. Each display area has 32 pixels.
With so many pixels, a graphics card is definitely needed, so people invented such a chip:
This is the most basic graphics card.
Persistence of vision
But the graphics card can only control one pixel at a time through horizontal and vertical!
This uses the persistence of vision of the human eye.
Persistence of vision means that when the eyes see the next picture, the afterimage of the previous picture will remain for a while. As long as we use persistence of vision to display the next pixel immediately while the afterimage of the previous pixel is still there, we can display multiple pixels.
3. How to display the color LCD
LCD is a popular display material since 2000. It can make the fuselage thinner and the color is much brighter than the previous CRT screen.
RGB color value
The computer pictures we see are actually determined by the brightness of the three colors. They are R (red, red), G (green, green), B (blue, blue). The varying brightness of these colors can determine a color.
当它们亮度都是255的时候就是白色，亮度都是0的时候是黑色。
液晶的透明度
上一章我们介绍过液晶，这种材料通电时变不透明，断电时是透明的。我们要控制RGB的值，只需要LED背光板把光打好，液晶的半透明形态阻碍一些RGB亮度，就能显示色彩了。
聚光片
刚刚的调RGB值还不够，这样你只能看到满屏红绿蓝。我们就需要聚光片把它们合成一个颜色。
有了这些，就能组成一块液晶屏了
