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Pay Attention to These 5 Points When Purchasing LCD Dot Matrix Screen

10.07.2023

What are the main parameters of the dot-matrix LCD? The dot-matrix LCD display is the most common type in life, and it is widely used. When choosing to purchase a dot-matrix LCD display, we must understand some relevant parameters, this is better to help us choose, let me explain to you the main parameters of the dot matrix display screen.

Dot matrix display 5 parameters:

1. Brightness

Liquid crystal is a substance between solid state and liquid state. It cannot emit light by itself, and it needs an additional light source. Therefore, the number of lamps is related to the brightness of the LCD. The earliest LCD only had two upper and lower light tubes. Up to now, the lowest of the popular type is four lights, and the high-end one is six lights. The four-lamp design is divided into three placement forms: one is that there is one lamp on each of the four sides, but the disadvantage is that there will be black shadows in the middle. The solution is to arrange the four lamps horizontally from top to bottom. The last one is the "U" shape, which is actually two lamps produced by two lamps in disguise. The six-lamp design actually uses three lamps. The manufacturer bends the three lamps into a "U" shape and then places them in parallel to achieve the effect of six lamps.

2. Contrast

Accessories such as control ICs, filters, and orientation films used in the manufacture of LCD panels are related to the contrast ratio of the panel. For ordinary users, a contrast ratio of 350:1 is enough, but in the professional field, such a contrast ratio is not enough. meet the needs of users.

Compared with CRT monitors, it is easy to achieve a contrast ratio of 500:1 or even higher. Only high-end liquid crystal displays can achieve such a level. Since the contrast ratio is difficult to accurately measure by the instrument, you still have to see it yourself when you choose it. Contrast is very important. 

3. Refresh Rate

The refresh rate of a dot matrix LCD display refers to the number of times the screen is refreshed per second. Watching TV or a movie is to play a still picture, similar to a slideshow. Human eyes have a visual stop effect. The previous picture has not disappeared in the brain, and the next picture has begun to appear. The interval between the two is very small, so it feels like the picture is moving. The replacement of a picture is a refresh. The refresh rate of a suitable dot matrix LCD screen is usually moderate, and now the refresh rate of the display has been improved very high for better gaming results. The DP level of the dot matrix LCD display video line is very high, and VGA is an analog signal. At present, DVI, HDMI, and DP are digital signals, which are currently common mainstream interfaces.

4. Response Time

The response time refers to the response speed of the LCD to the input signal, that is the response time of the liquid crystal from dark to bright or from bright to dark, usually in milliseconds (ms). To make this clear, we have to start with the human eye's perception of dynamic images. The human eye has the phenomenon of "visual residue", and the high-speed moving picture will form a short-term impression in the human brain. The latest games such as cartoons and movies have applied the principle of visual persistence, allowing a series of gradual images to be displayed in rapid succession in front of people's eyes to form dynamic images.

The acceptable screen display speed for people is generally 24 frames per second, which is also the reason for the movie playback speed of 24 frames per second. If the display speed is lower than this standard, people will obviously feel the pause and discomfort of the screen. Calculated according to this indicator, the display time of each picture needs to be less than 40ms. In this way, for the LCD display, the response time of 40ms becomes a hurdle, and the display below 40ms will have obvious "smearing" or "afterimage" phenomenon, which makes people feel chaotic. If you want the picture to reach a smooth level, you need to achieve a speed of 60 frames per second.

5. Picture Stabilization Technology

The picture refresh rate of the dot matrix LCD display is not necessarily synchronized with the picture output by the graphics card. If this happens, the picture delay and scene jumping will be caused. It will cause the conflict of two frames of pictures, which is manifested as the partial picture is out of synchronization with the whole, and the response is insufficient, and the like. This is not a smear, but a tearing of the picture. To solve the problem of dot matrix LCD screen, there is a solution, AMD's FreeSync and NVIDIA's G-SYNC, which is somewhat similar to the effect of vertical sync in games.

In addition to the image stabilization technology and refresh rate, as well as contrast brightness and response time, the important parameters of the dot matrix LCD display are of course many other related factors and corresponding technical parameters. For example, the refresh rate, interface, etc., the video line level of the dot matrix LCD screen is also relatively high, and the hardware structure of the display screen is simple, the software is easy to maintain, and the scalability is also strong.