Analysis:
The working principle of LCD is completely different from that of traditional CRT display. Its basic display element is liquid crystal material. Simply put, a liquid crystal display is a layer (or layers) of liquid crystal material sandwiched between two pieces of glass, and several lamps behind the glass continuously emit light. The liquid crystal material changes its light transmission state under the control of the signal, so that the image can be seen in front of the glass panel.
The performance of LCD is determined by the following aspects:
Response time
The response time is an important index to measure the quality of LCD. Response time refers to the response speed of LCD to input signals, that is, the response time of LCD from dark to bright or from bright to dark. Generally speaking, it is divided into two parts: Tr (rise time) and Tf (fall time), and the response time we refer to is the sum of the two. The shorter the response time, the better. If it exceeds 40 milliseconds, there will be a lag phenomenon of moving images. At present, the standard response time of LCD is mostly around 25ms, but a few models can reach 16ms. The super-fast response time of 16ms can display more than 60 frames per second, which completely solves the problem of smear and afterimage of traditional LCD when playing games or watching DVD.
contrast
Contrast refers to the brightness ratio between bright areas and dark areas of a display under specific lighting and observation conditions. Contrast is a parameter that directly reflects whether LCD can reflect rich color levels. The higher the contrast, the better the layering of the restored picture. At present, the nominal name of LCD is 250: 1 or 300: 1, and the high-end products are 400: 1 or 500: 1. It should be noted here that the contrast must match the brightness to produce the best display effect. A high contrast ratio of 400: 1 or 500: 1 will make the displayed picture more colorful and softer, making you play games or watch movies almost as good as a CRT monitor.
clever
The brightness of liquid crystal display is generally higher than that of traditional CRT display, and the brightness of liquid crystal display is generally in CD/m2 (lumen/square meter). The higher the brightness, the stronger the anti-interference ability of the display to the surrounding environment and the brighter the display effect. This parameter should be at least 200 cd/m2, preferably higher than 250 cd/m2. The higher the brightness of traditional CRT display, the greater its radiation, while the brightness of liquid crystal display is obtained through the backlight of cathode fluorescent lamp, so it has no negative impact on human body.
Bad screen
The most common bad spots on the screen are white spots or black spots. The identification method of black spots is to turn the whole screen into a white screen, so there is nowhere to hide black spots; White dots are just the opposite. Turn the screen to a black screen, and the white point will return to its original shape. Generally, a display screen with no more than three bad points is qualified, so users must pay attention to choosing products without bad points when purchasing LCD monitors. If you can't see any white spots and black spots, you can only choose big brands with guaranteed quality.
visible angle
Liquid crystal display (LCD) is a backlight display device, and the light it emits is provided by the backlight behind the liquid crystal module, which inevitably leads to the LCD having only one perfect angle-front view. When you look at it from other angles, because the backlight can penetrate the pixels next to it and enter the human eye, it will cause color distortion, and the undistorted range is the viewing angle of the liquid crystal. The viewing angle of LCD is also divided into horizontal viewing angle and vertical viewing angle, and the horizontal viewing angle is generally greater than the vertical viewing angle. At present, as long as the horizontal viewing angle reaches 120 degrees and the vertical viewing angle reaches 140 degrees, it can meet the application needs of most users. The latest LCD panel is made with wide viewing angle technology, which can reach up and down 140 degrees and left and right 150 degrees, reducing the inconvenience caused by too small viewing angle. Of course, this performance can't be compared with the viewing angle of CRT display close to 180 degrees, but it is more than enough for most applications.
dot pitch
The dot pitch of a liquid crystal display refers to the interval between each pixel constituting the liquid crystal display. At present, the standard pitch of mainstream 15 inch LCD products is generally 0.297mm, and the corresponding resolution is 1024×768. The visible area of LCD is "real", which generally means that the visible area of 15 inch LCD is close to that of 17 inch CRT display. The visible area of 15 inch LCD is 304. 1x228.438+0 (mm).
bandwidth
The bandwidth of LCD is also an index to measure LCD. Generally, the bandwidth of LCD is 80MHz.
Large-screen liquid crystal has the advantages of both liquid crystal and large-screen display, which makes large-screen liquid crystal products represented by 17 inch liquid crystal favored by consumers. In addition, its visual area is larger than that of 18 inch color TV, and it has the advantage of no radiation, so that users can enjoy it at close range.
thickness
Because the panel thickness of LCD itself is the same, that is to say, the main factors affecting the thickness of LCD will be the process of circuit controller, the design of plastic shell and the compression of internal space. Of course, the integration of a considerable number of cutting-edge liquid crystal technologies, the use of the latest ultra-thin liquid crystal panel and thinner high-brightness cold cathode fluorescent lamp, coupled with more integrated control IC design and more optimized heat dissipation treatment, can also achieve the purpose of reducing the overall size.
In a word, liquid crystal display has won the favor of more and more computer enthusiasts because of its real plane, ultra-thin body, low working voltage, low power consumption, low radiation, light weight, small size, no flicker, reducing visual fatigue, environmental protection and being beneficial to human health.