In the long and arduous innovation process of the PC industry, with the advancement of display technology, the classification of displays has become more and more detailed, which can be divided into flat-panel displays ( FPD ) and cathode ray tubes ( CRT ), also known as flat-screen displays. CRT is the overlord of the display when FPD is immature, the technology is mature, the cost is cheap, the color is accurate, and the response time is short. However, due to its huge size, flicker, image distortion and other fatal defects, the civilian market share is gradually replaced by FPD. A flat panel display, as the name suggests, is a display with a relatively thin thickness. It can be divided into LCD liquid crystal display, PDP plasma display, OLED organic light emitting diode display, FED field emission display, etc. In daily applications, only LCD liquid crystal display is popularized. Many people don't know what a CRT monitor is, and what are the differences between a CRT monitor and a liquid crystal monitor? The editor organizes the following relevant information:
What is a crt monitor?
The scientific name of the CRT display is "Cathode Ray Tube", which is a display that uses a cathode ray tube (Cathode Ray Tube). It mainly consists of five parts: Electron Gun, Deflection Coils, Shadow Mask, High Voltage Graphite Electrode and Phosphor Coating and Glass Housing. It is one of the most widely used monitors. CRT flat-screen monitors have large viewing angles, high color reproduction without dead pixels, uniform chromaticity, adjustable multi-resolution mode, and extremely short response time. LCD monitors are difficult to surpass. advantages, and the price is cheaper.
What is an LCD display?
Liquid crystal display, or LCD (Liquid Crystal Display), is a flat ultra-thin display device, which consists of a certain number of color or black and white pixels, placed in front of a light source or a reflective surface. Liquid crystal displays have low power consumption, so they are favored by engineers and are suitable for electronic devices that run on batteries. Its main principle is to stimulate the liquid crystal molecules to generate dots and lines, and the surface is matched with the back lamp to form a picture.
CRTs all claim that they have passed the "TCOXX" certification to show that their radiation is low and the harm to the human body is small, but no matter how small the radiation is, there will definitely be. The working principle of LCD determines that it does not have any radiation at all, so LCD often marks itself with words such as "zero radiation". In terms of volume, the depth of a CRT is approximately equal to its diagonal length, that is to say, the larger the display area of the CRT, the larger its volume, which often occupies a large amount of desktop space for users. And whether LCD is 15 inches or 19 inches, the thickness is only a few centimeters or ten centimeters, and it can even be hung on the wall, which CRT can't do anyway. In terms of price, the current price of a 17-inch flat-panel display using Trinitron picture tube is about 2500-3000 yuan, and the LCD with roughly the same viewing area is at least nearly 4000 yuan, and a slightly more expensive LCD It is often six or seven thousand yuan, which is not something that ordinary families can accept.
When it comes to color, LCDs are not as good as CRTs. In theory, CRTs can display as many colors as TVs. The LCD can only display about 260,000 colors, most of the products claim to be able to display 16.77 million colors (16,777,216 colors, 32 bits), but in fact they are all realized by dithering, which is different from the real 32 bits. There is still a big gap in color ratio, so it is still not as good as traditional CRT in terms of color expression and transition. By the same token, LCDs are not as good at representing grayscale as CRTs. If you have the conditions, you can compare it yourself. Next: find a 17-inch Trinitron display, and then place a 15-inch LCD to display a 16.77 million-color image at the same time. The picture displayed by the CRT is very bright, while the LCD is a bit "fake". Although there is nothing wrong with it, it is not as comfortable as the CRT with the long tube.
The display function of the liquid crystal display mainly has a light source of backlight, and the brightness of this light source determines the brightness and color saturation of the entire LCD screen. Theoretically speaking, the higher the brightness of the liquid crystal display, the better, the measurement unit of brightness is cd/m2 (square candle per meter), also called NIT lumens. At present, most of the brightness of TFT screen starts from 150Nits, and usually 200Nits can show a better picture. Contrast is also a measure of the contrast between the different levels of black and white. When the contrast ratio is 120:1, it can display vivid and rich colors (because the contrast ratio that the human eye can distinguish is about 100:1), and when the contrast ratio is as high as 300:1, it can support colors of all levels. The contrast ratio of most LCD monitors today is around 100:1 ~ 300:1. There is no fair standard value to measure the contrast value of brightness and contrast, so buying LCD depends on a pair of sharp eyes.
Most current flat-screen monitors have a viewing angle of 180 degrees, which means that the displayed content can be clearly seen from any direction in front of the screen. The LCD is different. Its viewing angle varies according to the advanced technology. The viewing angle of some new products can reach about 160 degrees, which is very close to the 180 degrees of CRT. There are also some LCDs with a nominal viewing angle of 160 degrees, but in fact they do not meet this standard. When the donkey is in use, once the viewing angle exceeds its actual visual range, the color of the picture will decrease, become darker, and even turn the positive image into a negative image.
Resolution is a very important performance metric. It refers to the number of dots that can be displayed in the horizontal and vertical directions on the screen (lines and surfaces displayed on the screen are composed of dots). The higher the resolution, the more information can be accommodated in the same screen. For a CRT that can support 1280x 1024 resolution, no matter it is 320x 240 or 1280x 1024 resolution, it can be performed perfectly (because the electron beam can be adjusted elastically). But its maximum resolution may not be the most suitable resolution, because if 17 pairs of monitors reach 1280x 1024 resolution, the font of WINDOWS will be very small, and the eyes will be easily fatigued for a long time, so the maximum resolution of the 17-inch monitor **Resolution should be 1024x768.
But not so for LCD. The maximum resolution of the LCD is its real resolution, which is the maximum resolution. Once the set resolution is smaller than the real resolution (such as 15-inch LCD, the real resolution is 1024x768, and the set resolution in WINDOWS is 800x600), there will be two display modes. One is the center display, only the 800x600 dots in the middle of the LCD will display the image, other unused dots will not emit light, keep the dark background, and it seems that the picture is centered and reduced. The other is to expand the display, which will use every pixel on the screen, but because the pixels are easily distorted, it will have a certain impact on the display effect.
