How to distinguish the quality of LCD?

How to distinguish the quality of LCD? The main parameters of LCD screen include contrast, brightness, display color, signal response time, visual angle, display color, screen refresh rate, resolution and resolution.

1. Contrast

It is difficult to accurately measure the contrast with the instrument, and it can only be judged by visual observation when the machine is turned on.

The contrast is related to the manufacturing materials of the liquid crystal panel, that is, the control IC, filter, alignment film and other accessories are of good quality, and the contrast is high. However, for ordinary users, the contrast can reach 350:1, while for professional users, the contrast requirements should be higher. At present, the contrast of high-grade LCD has reached 500:1 and 600:1, which can fully meet the needs of professional fields.

Since the liquid crystal itself cannot emit light, it needs to be illuminated with the help of external light source, i.e. lamp tube. Of course, the brighter the better, so the number of lamp tubes is directly related to the brightness of LCD. In the early stage, LCD had only two upper and lower tubes, and later developed to four tubes. Some high-end products had six tubes.

2. Brightness

The brightness is measured in CD / m2. If the brightness is too low, the picture will feel dark. At present, the brightness of TFT LCD is about 200cd / m2. For most users, the brightness of 150 ~ 200cd / m2 is OK.

3. Signal response time

Signal response time refers to the response speed of LCD to the input signal, usually in milliseconds (MS). According to the inspection ability of human eyes, when observing the moving picture, if the response time exceeds 40ms, there will be hysteresis of the moving image, resulting in residual shadow or trail of the picture. The less the response time, the better. However, it takes a process for the liquid crystal to turn from dark to bright. Therefore, the signal response time of LCD should generally be between 1 ~ 20ms, not more than 30ms.

4. Visual angle

The visual angle is divided into horizontal angle and vertical angle: the horizontal angle takes the vertical central axis of the LCD screen as the center, moves left and right, and can clearly see the angle scale of the image; The vertical angle is centered on the parallel central axis of the LCD screen, moving up and down to clearly see the angle range of the image.

5. Display color

Display color refers to the color representation of the displayed image. Early LCD can only display high color (256 colors) at most in color. Therefore, many manufacturers use the so-called FRC (frame rate control) technology to improve the picture color, but what they get is only "pseudo color". With the continuous progress of display technology, the current LCD color performance can reach the full-color (32-bit) mode.

6. Screen refresh rate

Screen refresh rate, that is, the frequency of screen refresh during display. It is related to the refresh speed of the picture. Different types of displays have different requirements for the refresh rate. For CRT display, the refresh rate is required to be above 75Hz. If it is lower than this value, the observer will feel that the picture flickers. The faster the refresh speed, the better the visual sense of the picture.

For LCD, the refresh rate is required to be 60Hz. Because in the LCD, each pixel continues to emit light until the signal that does not emit light is sent to the controller, the LCD will not have the flashing scene caused by continuous charge and discharge. Therefore, when the refresh rate is 60Hz, the LCD can obtain a good picture. At present, the screen refresh rate standard of LCD is set in the range of 60-75hz. Its purpose is to use flexibility and compatibility and finally replace CRT display.

7. Resolution

Resolution is one of the most important technical indicators of the display. The higher the resolution, the better the display effect. However, the resolution of LCD is different from that of CRT display. It is composed of pixels arranged in rows and columns. The number of pixels in each row and column are set and specified by the manufacturer. Therefore, the resolution of LCD cannot be adjusted arbitrarily. LCD can achieve the best display effect only when it works in the nominal resolution mode.

Shenzhen Yuhua Micro Technology Co., Ltd. is a company engaged in the development and sales integration of LCD and LCM. It is located in Longhua new area, Shenzhen. It has superior geographical location, beautiful environment and convenient transportation. In addition, the company has gathered backbone talents with rich experience and operation ability in marketing, product R & D, product production, project implementation, customer service and technical training, and has strong management and technical ability.