How to choose a suitable LCD display

With the popularity of LCD prices, many friends began to abandon CRT and choose LCD display. Compared with traditional CRT monitors, LCD monitors offer a slightly higher price, but have many advantages: no radiation, small size, low power consumption, beautiful appearance, etc, although there are problems such as limited viewing angle, slow response speed, and weak expressiveness, the impact on office use is not great. At present, many of my friends do not know what points should be paid attention to when purchasing the product. Here we will make a simple and easy-to-understand analysis of its principle to help you identify the advantages and disadvantages of LCD.

First, let's look at the basic principles of LCD. From the introduction of LCD, we often find the abbreviation of TFT, which is the abbreviation of thin film transistor, the Control Unit of LCD. At present, most LCD displays on the market belong to tft LCD panels, which display graphics by controlling the light usage of each pixel, it features low operating voltage, low power consumption, light weight, thin thickness, and easy to display in full color.

When purchasing an LCD, many friends don't know how to judge a long string of parameters. They often make a choice just by looking at the appearance. Below, we will avoid the appearance of the factors, with the author on hand a mainstream LCD display technical parameters for reference, one by one to illustrate how to use the parameters provided by the manufacturer to choose a LCD display:

LCD Panel	15 inch
Brightness	250 cd/m2 (lumen)
Contrast	400: 1
Response time	16 Ms
Optimal resolution	1024*768 @ 60Hz
Horizontal Visual Angle	120 degrees
Vertical Visual Angle	100 degrees
Power	36 w
Authentication	Tco99, CCC

　　

I. LCD Panel

The difference between the LCD Panel size and CRT is that the LCD panel is used to calculate the visible size. Generally, the visible area of a 17-inch CRT display is 15.6 ~ Therefore, the actual display area of a 15-inch LCD is almost the same as that of a 17-inch CRT. Similarly, the actual display area of a 17-inch LCD is about the same as that of a 19-inch CRT. Generally, the Panel size parameters are correct. However, we should also pay attention to the thickness, frame size and bracket design, which not only affect the appearance, but also affect the convenience of use.

Ii. brightness

Liquid Crystal is a substance between a liquid and a crystal. It can control the penetration of light through the current to display the image. However, the LCD itself does not emit light, so all LCD displays require backlight lighting, and the brightness of the backlight determines the brightness of the monitor. High Brightness makes the display layers richer, thus improving the display quality. In theory, the higher the brightness of the monitor, the better, but the higher the brightness, the greater the stimulus to the eyes, so users without special needs do not need to pursue too high brightness. The unit of brightness is cd/m2 (lumens). The brightness of this LCD is 250cd/m2, which is the mainstream brightness level in LCD, this brightness can be used normally. In addition, it should be noted that, according to the arrangement of the tubes, some LCD monitors may have uneven brightness, so be careful when buying them.

Iii. Contrast

The backlight of a liquid crystal display is continuously lit, and the LCD panel cannot completely block the light. Therefore, it is very difficult for a liquid crystal display to achieve a full black screen. In the same brightness, the deeper the black color, the richer the display color layers. Therefore, the contrast of the LCD is very important. The average person's eye can accept the contrast is generally around 250: 1, lower than this contrast will feel blurred or gray. The higher the contrast, the higher the sharpness of the image, and the clearer the image. Generally, the CRT display can easily reach 500: 1 or higher, while the LCD display can reach 400: 1. Generally, the LCD display contrast is 300: 1, which is sufficient for document processing and office applications. However, playing games and watching movies requires a higher contrast to achieve better results.

Iv. Response Time

The response time determines the number of frames that the monitor can display per second. Generally, when the screen display speed exceeds 25 frames per second, the human eye will regard the rapidly changed screen as a continuous screen without any pause, therefore, the response time will directly affect your visual experience. When the response time is 30 ms, the display can display 1/0 per second. 0 30 = 33 frames. The response time is 25 ms, and 1/0 is displayed every second. 025 = 40 frames. The shorter the response time, the more images the monitor displays per second. At present, the response time of mainstream LCD monitors in the market is below 30 ms, so the basic image smoothness can be achieved. However, when playing a DVD, quake, Cs, and other games, the screen display speed must be more than 60 frames per second to achieve the best effect. The response time of this product we refer to is 16 ms, which is the shortest response time that can be achieved at present. The response time can be displayed at 1/0 per second. 016 = 63 frames, more than enough for normal 3D games and video playback.

5. Resolution

The display of the LCD panel is like a small door or switch arranged to let the light pass. The pixels that the LCD screen can display are determined by the number of these small doors and switches, therefore, the physical resolution of the LCD is fixed. In daily application, it is impossible to always use the same resolution. For CRT display, as long as the deflection voltage of the electron beam gun is adjusted, new resolutions can be received; however, the LCD display is much more complicated. The display effect must be simulated through computation, but the actual resolution will not change. Because all pixels are not amplified at the same time (from the 640x480 resolution to the 1024x768 resolution magnification of 1.5), there is a scaling error. When the LCD uses a non-standard resolution, the text display effect is not satisfactory. Therefore, we recommend that all consumers who use a 15-inch LCD Use A x resolution. In addition, due to the impact of response time, the LCD display flushing rate is not as high as possible. Generally, it is best to set it to 60Hz, that is, change the screen 60 times per second, increasing the image size will affect the image quality. Therefore, you do not have to pursue a high rate of refreshing.

Vi. Visual Angle

The LCD display is a backlight shot through liquid crystal and polarized glass. The principle is very similar to the louddb for curtains. The vast majority of the light is vertical. In this way, when we look at the LCD from a non-vertical direction, we often see that the screen is dark or the color is distorted. This is the perspective of the LCD. In daily use, several people may watch the screen at the same time, so the larger the visual angle, the better. However, for the current technology, the horizontal angle is 90 ~ 100 degrees, vertical angle 50 ~ 60 degrees can be used normally. Pay attention to the preceding parameters when selecting this parameter. After all, there are very few people watching the display at the same time, especially for home users, the visual angle is relatively less important.

VII. Power

Generally, few people pay attention to the power when buying an LCD, while the power of the LCD should be below 50 W. We can see from this parameter that the power of this LCD product is only 36 w, and the power of more than W of CRT display is very energy-saving and environmentally friendly. In fact, this is also one of the important reasons for many large organizations to fully adopt LCD.

8. Authentication

I am afraid that the tco99 certification has been widely recognized by the media? Tco99 has strict quality certification standards, and even requires that the materials used to make the display cannot be harmful to the human body, nor damage the environment. Therefore, whether the monitor has passed the relevant authentication is also one of the selection criteria. This monitor is marked by tco99 and CCC certification. CCC certification is currently a popular "3C" certification, in addition to strict requirements on the display radiation, there are also many requirements for the manufacture of display materials and manufacturing process. After the "3C" certification was fully implemented in August this year, products that did not pass the "3C" certification will not be sold in the market, so we do not have to worry too much about certification in the future.

The development of display devices is changing with each passing day. At present, the most important technologies of LCD display are also advancing by leaps and bounds. Every step forward of these display technologies will affect our selection and use. I hope that you can get a rough idea of the several elements of LCD and buy the most suitable product based on your needs.

Text/Xiaoshi