Brightness and contrast: Brightness and contrast can be said to be the most basic conditions for judging the quality of liquid crystal displays. Usually the screen has a higher brightness value to make the picture brighter, and the LCD screen needs a brightness value of at least 200cd/m2 to display a picture that meets the basic requirements. Of course, the higher the brightness value, the better the performance. The picture is also more vivid. Contrast refers to the brightness contrast between black and white colors. In other words, a liquid crystal display with high contrast can display richer color levels. Basically, the contrast index of the liquid crystal display must be at least 200:1, otherwise, uneven color blocks may appear when displaying pictures with the same color gradient, and the display texture is poor. Of course, the higher the value of this indicator, the better.
Signal reaction time: The signal reaction time refers to the time required for each pixel of the liquid crystal display to go from dark to bright and from bright to dark. The general specification indicates the average value of the above two, but some manufacturers will list both values. For consumers who want to use LCD to play games and watch movies, this data is very important. If the signal response time is too long, the dynamic picture is prone to afterimages, and the display effect will be greatly reduced.
Generally speaking, the signal response time of the current liquid crystal displays on the market should be below 30ms, and even models below 15ms can be seen everywhere. If the user has a large number of dynamic picture needs, such as game players, it is best to choose a product with a shorter response time.
In addition to the proper nouns that often appear in the manual, there is an important criterion for the quality of LCD monitors: the number of bright spots. The so-called bright spot is a pixel (pixel) that is continuously lit and does not accept the extinguishing signal, which is also called a dead pixel. Bright spots are usually not easy to detect, and users have to watch them carefully in a completely black screen to find them.
The bright spot can be said to be a unique problem of the liquid crystal display. The cause is: in the process of manufacturing the LCD panel, the good rate cannot reach 100%, so there will be a bright spot problem when leaving the factory. Generally speaking, the number of bright spots of A-level panels is limited to 3 or less, and some brands also offer no bright spot guarantee. If the bright spot exceeds the quantity standard specified by the manufacturer, it can usually be replaced with a new one.
To check whether the LCD monitor has bright spots, you can use graphics software (the simplest tool is the drawing that comes with Windows) to draw a black picture, and zoom in to the full screen state (such as 1024X768 resolution), and then carefully check the screen Are there any shiny dots. In addition, after long-term use, LCD displays sometimes gradually appear bright spots. Therefore, after consumers get the product, they may wish to start the test. If you find that the number of bright spots exceeds the standard, you can ask the merchant to replace the new product.
How to judge whether the screen display effect is good or bad? For ordinary consumers who don't have much professional knowledge, the easiest way is as long as they feel that the most comfortable display screen is the best effect. If you feel that the picture is blurry, the image is stagnant, or the font is unclear, it must be a poor-quality LCD.
During the actual test, you can do it in the following ways: browse the Internet web page to observe the clarity of the color and text, and observe whether the scroll bar of the screen is stagnant or residual image; open the word processing software to observe whether the font is clear; open the highest quality Observe the clarity and softness of the picture; observe the clarity of the video playback, carefully observe the performance when zoomed in to the full screen, and whether the video playback is stagnant or delayed.
Signal input mode: Most LCD displays provide a traditional analog 15-pin D-type interface (15pinD-sub). At present, some high-end liquid crystal displays adopt the coexistence method of digital DVI interface (DigitalVisualInterface) and analog interface. As long as the user has a DVI display card, he can use the DVI connector as a signal input to present a better display effect on the LCD.
Viewing angle: When the LCD monitor is viewed from the side, the color deviation often occurs, and in severe cases, it is even completely unclear. Therefore, the size of the viewing angle is also regarded as an indicator for evaluating the quality of the display. Generally speaking, the viewing angle is divided into horizontal viewing angle and vertical viewing angle. The value of the viewing angle must be at least 120 degrees or more. Of course, the larger the angle value, the more people can crowd together to watch.