TFT-LCD structure

- Aug 22, 2018-



The LCD consists of two glass plates, approximately 1 mm thick, separated by a uniform spacing of 5 μm containing liquid crystal (LC) material. Since the liquid crystal material itself does not emit light, a light pipe as a light source is provided on both sides of the display screen, and a backlight plate (or a light homogenizing plate) and a reflective film are formed on the back of the liquid crystal display, and the backlight plate is composed of a fluorescent substance. Light can be emitted, the main function of which is to provide a uniform background light source. The light emitted by the backlight enters the liquid crystal layer containing thousands of crystal droplets after passing through the first polarizing filter layer. The crystal droplets in the liquid crystal layer are all contained in a small cell structure, and one or more cells constitute one pixel on the screen. Between the glass plate and the liquid crystal material is a transparent electrode, the electrode is divided into rows and columns, at the intersection of the rows and columns, by changing the voltage to change the optical rotation state of the liquid crystal, the liquid crystal material acts like a small light valve. Around the liquid crystal material are a control circuit portion and a drive circuit portion. When the electrodes in the LCD generate an electric field, the liquid crystal molecules are distorted, and the light passing through them is regularly refracted, and then filtered through the second layer of the filter layer to be displayed on the screen.

   The disadvantages of liquid crystal displays are that there is a significant difference in brightness, picture uniformity, viewing angle and reaction time from CRT displays. The reaction time and viewing angle depend on the quality of the liquid crystal panel, and the uniformity of the image has a great relationship with the auxiliary optical module. The brightness of a liquid crystal display depends mainly on the backlight source. Of course, the design of the entire module is also a factor that affects the brightness of the product.

    Many people use "lumen" when describing the brightness unit, but this is actually wrong. In fact, "lumen" is the unit of luminous flux, and the unit of brightness should be cd/m2 (superscript). Both are technical parameters for the field of optics. The sum of the amount of light emitted by the illuminant per unit time is called luminous flux, and is symbolically used in physics. The luminous flux of the illuminant in a unit area of a solid angle unit in a specific direction is called luminace, and is represented by L in physics, and the unit is candela per square meter or square candle cd/m2. Brightness is an important indicator of the luminous intensity of a display. It is especially important for liquid crystal displays. High brightness means that the display has higher anti-interference ability to the surrounding environment, and the TCO'03 certification standard for liquid crystal displays also has quite high requirements. Manufacturers also use high brightness as one of the selling points of their products. In general, manufacturers increase the brightness of liquid crystal displays by increasing the number of lamps and optimizing the internal design of the display.

    From this, we can see that the performance of the LCD has a considerable relationship with the panel material, and the quality of the panel will directly determine the performance of the LCD display. In the market, the panels used in LCD monitors such as 12ms, 16ms, and 25ms are different. However, a good panel means a higher price, and the high-quality panels in the hands of Sharp, Samsung, LG and other manufacturers are also quite expensive. Taiwanese manufacturers also have well-known manufacturers such as AUO. Their products are cost-effective, and many monitors on the market use their products. Pure EZX15F2 is one of them. Its brightness is 400cd/m2 and the contrast ratio is 550:1. The average similar product has a brightness of 250cd/m2 and a contrast ratio of 300:1. And its corresponding time is only 16ms, fully capable of all kinds of applications. Its viewing angle is up to 163 degrees / vertical 135 degrees, and also exceeds other brands of LCD monitors of the same price. Excellent panel materials, extraordinary technical parameters, high quality performance, what are you waiting for?