【 Weak current College 】 LCD display principle and explain more about nouns (1) 】

1. liquid crystal display principle

LCD is an abbreviation for the English LiquidCrystalDisplay, LCD monitor, is a digital display, you can through the LCD and colour filter light, flat panel produce images. Unlike traditional cathode ray tube (CRT) compared to LCD footprint small, low power, low-e, flicker-free, reduce visual fatigue. Inadequate: and the same size as compared to CRT, prices are more expensive.

In the notebook computer market occupies a leading position in many years, based on the liquid crystal display technology for smooth display screen is gradually into the desktop market. LCD has many traditional CRT display technology advantages not available to provide greater clarity of the text display, and the screen flicker-free, thus effectively reducing long time watching the screens generated by the Visual fatigue. LCD monitor of thickness is less than 10 inches, if the desktop system with LCD technology, will save even more space. Although the LCD monitor has a unique feature of its attractive, but it is undeniable, and its main competitors, LCD over CRT monitors in high-quality color display is still inadequate, in addition, the price differences make the differences in the LCD is still only a few people enjoy luxury products.

Early in 1888, it was found that is liquid liquid chemicals, like the metal in a magnetic field, when subjected to the influence of external electric field, its elements will have a precise and orderly arrangement. If the arrangement of the elements to be properly controlled, liquid crystal molecules will allow light to pass through. Whether it is a laptop or desktop system, using the LCD screen is made of different parts of the hierarchy. Located on the back of a layer by fluorescent substance can be fired light backlight layer. Backlight layer of light in through the first layer polarization filter layer after entering the Crystal droplets containing thousands of liquid crystal layer. Liquid crystal layer of Crystal droplets are contained in a small cell structure, one or more cells to form a pixel on the screen. When the LCD produces electric field in the electrode, the liquid crystal molecules will produce distortions, so will crossing them light refraction of a rule, and then after the second layer filtering layer filter displayed on the screen.


For simple monochrome LCD monitor, such as Pocket PC's screen, the structure was enough. But for laptops using more complex color display, you also need to have special handling color display of the color filter layer. Usually, in the color LCD Panel, each pixel is composed of three LCD cell components, each of these cells are preceded by the red, green, or blue filters. In this way, through different cell light can be displayed on screen in a different color. Now, almost all applications in notebook or desktop system LCD uses thin film transistor (TFT) liquid crystal layer in the active cell. TFTLCD technology capable of displaying more clear, bright image. Early LCD as a non-active devices, the speed is low, the efficiency of poor contrast, while the ability to show a clear text, but in the fast display image often have shadows, affects the video will appear, therefore, now only needs to be applied to black and white display PDA, pager or cell phone.

Affected by the LCD layer in the actual number of cells, LCD monitor General can only provide a fixed display resolution. If the user needs to be 800 x 600 resolution to 1024X768, specific software only with the help of analog.

Unlike traditional CRT monitor, apply to desktop systems with LCD also is designed to receive waveform analog signals, rather than directly from PC-generated digital pulse signal. This is mainly due to the current desktop system in most of the standard graphics card is still in the video information from the digital signal into an analog signal and then routed to the monitor display. Although desktop system LCD is designed to receive analog signals, but the LCD itself still can only handle digital information, so when received from the video, the LCD analog signal to analog signal and then revert to digital signal processing. In order to address the above issues are displayed on the inadequacy of the latest desktop LCD uses a special kind of graphics card with a digital connector directly to transmit digital signals for LCD monitor.

With LCD technology continues to mature and develop, the size of the display screen is gradually increased. Previous notebook computer is an 8-inch (diagonal) fixed-size LCD monitor, TFT technology now, based on a desktop system LCD can support 14-to 18-inch display panel. Because the manufacturer in accordance with the actual size of the viewable region to determine the size of LCD, CRT and not by the size of the picture tube, so in General, the size of 15 inch LCD is equivalent to traditional 17-inch color display size.