1. Contrast

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

The contrast is related to the materials used to make the LCD panel, if the quality of the control IC, optical filter, alignment film and other accessories is good, the contrast will be high, but for general users, the contrast can reach 350: 1. For professional users the contrast requirement should be higher. At present, the contrast ratio of high-end LCD has reached 500: 1 and 600: 1, which can fully meet the needs of professional fields.

Because the liquid crystal itself cannot emit light, it needs an external light source, that is a lamp to illuminate. Of course, the brighter the brightness the better. Therefore, the number of lamp tubes is directly related to the brightness of the liquid crystal. The early LCD only had two upper and lower light tubes, and later developed to 4 light tubes, and some high-end products have 6 light tubes.

2. Brightness

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

3. Signal Response Time

Signal response time refers to the LCD's response speed to input signals, usually in milliseconds (ms). According to the inspection ability of the human eye, when observing a moving picture, if the response time exceeds 40ms, the hysteresis phenomenon of the moving image will appear, resulting in afterimages or trailing traces of the image. The shorter the response time, the better, but it takes a process for the liquid crystal to change from dark to bright, so the signal response time of the LCD should generally be between 1-20 ms, but not more than 30 ms.

4. Viewing Angle

The viewing angle can be divided into horizontal angle and vertical angle: the horizontal angle is centered on the vertical axis of the LCD screen, moving left and right, you can clearly see the angle scale of the image; the vertical angle is centered on the parallel axis of the LCD screen, up and down moving, the angular range of the image can be clearly seen.

5. Display Color

Display color refers to the representation of an image in terms of color. Early LCDs could only display high colors (256 colors) in terms of colors. Therefore, many manufacturers use the so-called FRC technology to color the screen, but what they get is only "false color". With the continuous advancement of display technology, the current LCD color performance can already achieve full-color (32-bit) mode.

6. Screen Refresh Rate

Screen refresh rate, that is, the frequency at which the screen is refreshed during the display process of the display. Related to the refresh rate of the screen, different types of monitors have different requirements for the refresh rate. For CRT monitors, the refresh rate should be above 75Hz. If the refresh rate is lower than this value, the viewer will perceive the picture flickering. The faster the refresh rate, the better the visual sense of the picture.

For LCD, the refresh rate should be 60Hz. Because in the LCD, each pixel is continuously emitting light until the signal that does not emit light is sent to the controller, so the LCD will not appear the flickering scene caused by continuous charging and discharging. Therefore, when the refresh rate is 60Hz, LCD can get a good picture.

The current standard for the refresh rate of LCD screens is set in the 60-75hz range, aiming to take advantage of flexibility and compatibility, and eventually replace CRT monitors.

7. Resolution

Resolution is usually divided into high resolution and low resolution. The level of resolution has a direct impact on the quality of the image presented on the screen, but different types of displays have different requirements for resolution.

The image of a traditional CRT display is mainly realized by dots and lines composed of pixels, so the number of pixels is an important factor affecting the resolution. However, the resolution supported by CRT monitors is quite flexible, it can display in high resolution and low resolution.

The LCD display only supports "real resolution", that is, high resolution, because the LCD display can only display the best image effect under the "real resolution". The real resolution of LCD is defined as "fixed-point form", which can be set to the highest when used.

8. Resolution

Resolution is one of the most important technical indicators of a display, the higher the resolution, the better the display effect. However, LCD displays have a different resolution than CRT displays, and are made up of pixels arranged in rows and columns. The number of pixels in each row and column is set and specified by the manufacturer, so the resolution of the LCD cannot be adjusted at will. Only when it works in the nominal resolution mode can the LCD achieve the best display effect.