1、 Brightness of LCD screen
The unit of brightness for LCD screens is cd/m2. For example, 250cd/m2 indicates that the brightness of lighting 250 candles in an area of 1 square meter is equal. LCD itself does not emit light, so LCD displays require backlighting, and the brightness of the backlight also determines the brightness of the LCD screen. The maximum brightness is usually determined by a cold cathode ray tube (backlight).
There are currently two methods to improve brightness, one is to increase the transmittance of the LCD panel; Another way is to increase the brightness of the background light, which is to increase the number of lamp tubes. Although higher brightness can be achieved technically, it does not necessarily mean that higher brightness values are better. If higher brightness is used, the viewer's eyes may be harmed. In addition, according to the arrangement of the lamp tubes, some LCD displays may have uneven brightness, so it is important to be cautious when choosing.
Secondly, the contrast of the LCD screen
The definition of contrast is the ratio of the maximum brightness value (all white) to the minimum brightness value (all black). For example, if we measure the white brightness of an LCD screen to be 250nits and the black brightness to be 0.5nits, we can obtain a display contrast of 500:1 by using the formula black and white=contrast. Similarly, if the dark part is darker and the bright part is whiter, the contrast is higher; otherwise, the contrast is lower.
Improving contrast has an immediate effect on improving image quality, as higher contrast means clearer contrast between light and dark in the image, resulting in a more layered and three-dimensional appearance.
There are two methods to increase contrast: increasing the brightness of white images or decreasing the brightness of black images. The method of increasing contrast by increasing brightness is much simpler, but blindly increasing brightness can bring many drawbacks, such as increased power consumption, severe light leakage, and shortened lifespan. Therefore, most manufacturers focus on reducing the brightness of black images.
Manufacturers have also been committed to improving the phenomenon of light leakage. The higher the contrast, the more color levels can be distinguished. The IC control chip, filter, directional film and other raw materials of LCD display directly affect the contrast of LCD display. The manufacturer of Ruxin High Brightness LCD Display has increased the contrast technology to 5000:1, far exceeding the standard of 500:1 for ordinary displays.

Thirdly, the dot spacing of the LCD screen
Point spacing generally refers to the distance between two adjacent pixels on a display screen. The image we see is composed of many points, and the level of image quality is determined by the distance between the points.
The dot spacing of a liquid crystal screen is the distance between two liquid crystal particles (light dots). The calculation method for point distance is to divide the panel size by the resolution. Due to the fixed number of pixels in LCD, the pixel spacing of LCD is also the same when the size and resolution are the same. For example, the dot pitch of a 22 inch LCD panel is 0.282mm, and its calculation method is length (47.3cm) or width (29.6cm)/length pixel 1680 or width pixel 1050=0.282mm.
What is the function of LCD screen pitch?
The dot distance of a LCD screen is the distance between two liquid crystal particles (light dots), which affects the precision of the image. Generally speaking, the smaller the dot pitch, the finer the image, but the smaller the characters. On the contrary, the larger the dot spacing, the larger the font, the clearer the outline, and the easier it is to see, but the image will appear rough. So the choice of point distance needs to be balanced between text, images, and video applications, and cannot be too large or too small. The most comfortable point distance is generally between 0.27mm-0.30mm.
For example, a 15 inch LCD can clearly display font 5, while a 20 inch LCD can clearly display font 4. For example, the dot pitch of a 20 inch widescreen LCD in our daily life is significantly smaller than that of a 19 inch widescreen LCD, giving the impression that the image seen on a 20 inch widescreen LCD is more delicate than that seen on a 19 inch widescreen LCD.
In this situation, watching a 20 inch widescreen LCD for a long time will be more harmful to the eyes than watching a 19 inch widescreen LCD. Therefore, for the sake of protecting the eyes, for users who do not have precise requirements for the screen, it is recommended to use LCD screen products with the same size and large dot spacing.