What does display mean, what are the computer display properties?

- May 21, 2020-

 

In the liquid crystal industry, many people like to use display expressions, such as Liquid Crystal Display (LCD), so in the liquid crystal panel industry, what does display mean? What are the computer display properties that are closely related to us?

 

display

 

In the LCD industry, the display verb means display, and the noun refers to the display. We mainly talk about the display here. The monitor is an I / O device belonging to a computer, that is, an input and output device. It is a display tool that displays certain electronic files on a screen through a specific transmission device and then reflects them to the human eye.

 

According to different manufacturing materials, it can be divided into: cathode ray tube display (CRT), plasma display PDP, liquid crystal display LCD and so on. The former has been basically eliminated, and now the mainstream market is LCD displays.

 

"What does computer display mean"

 

What are the computer display properties?

 

The computer display properties, which can be seen in the control panel, include the display brand, display allocation rate, refresh rate, material, etc. In addition to these most basic information, display attributes also include viewing area, viewing angle, dot pitch, color, contrast, and so on.

 

Visible area

 

The size marked on the LCD is the same as the actual screen range. For example, a 15.1-inch LCD display is approximately equal to the viewing range of a 17-inch CRT screen.

 

Viewing angle

 

The viewing angle of a liquid crystal display is symmetrical from side to side, but not necessarily from top to bottom. When the incident light of the backlight passes through the polarizing plate, liquid crystal and alignment film, the output light has specific directional characteristics, that is, most of the light emitted from the screen has a vertical direction. If you look at a completely white screen from a very oblique angle, you may see black or distorted colors. Generally speaking, the up-down angle should be less than or equal to the left-right angle. If the viewing angle is 80 degrees to the left and right, it means that the screen image can be clearly seen when the position starts at 80 degrees from the screen normal. However, due to different human vision ranges, if you do not stand within the best viewing angle, the color and brightness you see will have errors. On the market, the viewing angle of most LCD monitors is around 160 degrees. With the development of technology, some manufacturers have developed various wide viewing angle technologies in an attempt to improve the viewing angle characteristics of liquid crystal displays.

 

Dot pitch

 

It is often asked what the dot pitch of the LCD is, but most people do not know how to get this value. Generally, the visible area of a 14-inch LCD is 285.7mm × 214.3mm, and its maximum resolution is 1024 × 768, then the dot pitch is equal to: visible width / horizontal pixels (or visible height / vertical pixels).

 

Color

 

The most important thing about LCD is the color expression. We know that any color in nature is composed of three basic colors of red, green and blue. The LCD panel is composed of 1024 × 768 pixels, and the color of each independent pixel is controlled by three basic colors of red, green, and blue (R, G, B). Most of the LCDs produced by manufacturers have 6 basic colors (R, G, B), or 64 expression levels. Many manufacturers also use the so-called FRC (Frame Rate Control) technology to display full-color images in a simulated manner, that is, each basic color (R, G, B) can reach 8 bits, that is, 256 expression levels .

 

Contrast value

 

The contrast value is the ratio that defines the maximum brightness value (full white) divided by the minimum brightness value (full black). The contrast value of a CRT monitor is usually as high as 500: 1, so that it is easy to present a truly black screen on the CRT monitor. However, it is not easy for LCD. The backlight composed of cold cathode ray tube is difficult to switch quickly, so the backlight is always on. In order to get a completely black screen, the liquid crystal module must completely block the light from the backlight, but in terms of physical characteristics, these components cannot fully meet such requirements, and there will always be some light leakage. In general, the acceptable contrast value for the human eye is about 250: 1.

 

Brightness value

 

The maximum brightness of a liquid crystal display is usually determined by a cold cathode ray tube (backlight), and the brightness value is generally between 200 and 250 cd / m2. The brightness of the LCD monitor is slightly lower, and the screen will feel dark. Through years of experience accumulation, the brightness of LCD monitors on the market today is generally 250cd / m2, and monitors over 24 inches are slightly higher, but they are basically maintained at 300-400 cd / m2, although they can be technically higher Brightness, but this does not mean that the higher the brightness value, the better, because a monitor with too high brightness may damage the viewer's eyes.

 

Response time

 

The response time refers to the speed at which each pixel of the liquid crystal display reacts to the input signal. Of course, the smaller the value, the better. If the response time is too long, it may make the LCD display have the feeling of trailing tail when displaying dynamic images. The response time of general LCD monitors is between 5 and 10ms, and the response time of first-line brand products is generally less than 5ms, which basically avoids the problem of tail drag.

 

 

 

scanning method

 

The scanning method refers to the scanning method of the electron gun in the picture tube to the screen.