The TFT-LCD liquid crystal display is a thin film transistor type liquid crystal display, which is also a "true color" (TFT). The TFT liquid crystal is provided with a semiconductor switch for each pixel, and each pixel can be directly controlled by a point pulse, so each node is relatively independent and can be continuously controlled, which not only improves the reaction speed of the display screen, but also can accurately control. The color gradation is displayed, so the color of the TFT liquid crystal is more true.
TFT liquid crystal display features high brightness, high contrast, strong layering, and bright colors, but there are also deficiencies in power consumption and high cost. TFT liquid crystal technology has accelerated the development of mobile phone color screens. Color screen mobile phones basically support 65,536 colors, and there are 260,130,000 displays, and some even support 16 million color display. At this time, TFT's high contrast and rich color advantages are very important.
The liquid crystal display consists of two parts: a liquid crystal panel and a backlight:
The liquid crystal panel (liquid crystal cell) includes a polarizing plate, a glass substrate, a color filter film, an electrode, a liquid crystal, and an alignment layer.
The backlight module is composed of a cold cathode fluorescent lamp (CCFL), a light guide plate (optical waveguide), a diffusion plate and a prism sheet, and functions to uniformly transmit the light source to the liquid crystal panel.
(1) LCD panel
a. Polarizer: divided into an upper polarizer and a lower polarizer, the upper and lower polarizers are perpendicular to each other. Its function is like a fence, it will block the light wave component perpendicular to the fence, and only allow the light wave component parallel to the fence to pass.
b. Glass substrate: The glass substrate and the lower glass substrate are separated, and are mainly used for sandwiching the liquid crystal. For the TFT-LCD, the lower glass has a thin film transistor (TFT), and the upper glass has a color filter film. c. Color filter film: produces three primary colors of red, green and blue.
d. Electrode: Divided into a common electrode and a pixel electrode. A signal voltage is applied between the pixel electrode and the common electrode. e. Liquid crystal material: small molecule organic compound.
f. Orientation layer: Also known as an alignment film, its function is to enable liquid crystal molecules to be aligned. Screen resolution terminology
1. brightness
Brightness indicates the luminous intensity of the television. It is expressed by the brightness per unit area of ​​cd/m2 (candela per square meter). The average brightness when watching TV: about 50 ~ 70cd / m2, the average brightness of the cinema screen: about 30 ~ 45cd / m, the average brightness of outdoor TV: 300cd / m2.
The brightness is too large, wastes energy, reduces the life of the TV, and speeds up the aging of the TV. For a flat panel display, the brightness is sufficient. 2. Contrast
Contrast is expressed as the ratio of maximum brightness to minimum brightness, ie: The higher the contrast, the more layers you can reproduce and the higher the image quality. The greater the brightness of ambient light on the screen, the smaller the image contrast. 3. Grayscale (grayscale)
Grayscale: Shows the difference between light and dark pixels.
The more gray levels, the clearer the image hierarchy is.
For example: pixel grayscale of 16-bit image: there are 2 to 16 powers, that is, 65,536 gray scales. The higher the number of bits, the richer the transition between the light and dark of the image, and the better the detail. 3.4.3 Response speed
Response speed: The speed at which each pixel responds to the excitation voltage, that is, the time it takes for the pixel to turn from dark to bright or from bright to dark. For a liquid crystal television, the response speed is the time during which the voltage is applied to the liquid crystal molecules to reverse or recover the liquid crystal molecules. The 25 ms and 16 ms are often referred to as the response time.
The shorter the reaction time, the less the user will feel the tailing when watching the dynamic picture. CRT TV: 1~3ms LCD TV: 25ms~12ms
SMD resistor and capacitor: denoted by the mark "R/C"
Resistance: Generally expressed by three digits: Example: 102 means 10X102 ohm capacitor: generally expressed by three digits and marked with withstand voltage: Example: 106 16v means 10X106 PF=10uf withstand voltage value is 16V.
ROM: read only memory
Features: Store data, turn off power data still exists.
Classification: ^ EPROM Programmable Read Only Memory 1, with window, can be used multiple times, 2, no window, one-time EEPROM can be electrically erased read-only memory 1, erasable and rewriteable
^ FLASHROM Quick Erase Read ROM 1, which can be quickly erased.
DRAM (Dynamic Random Access Memory) Type:
SDRAM SGRAM DDRAM
VGH: gate electrode turn-on voltage (10~16V) VGL: gate electrode turn-off voltage (-5~-10V) VCC: analog circuit power supply (2.5~3.3V) IOVCC: digital circuit power supply. (1.65~3.3V)
GVDD: This voltage is connected to the resistor string to generate the gamma voltage. VCOM: LCD reverses the reference voltage.
Cs: The storage capacitor, the main function is to store the charge and keep the picture until the next update. Brand screen:
LG LCD screen, AU LCD screen, Hitachi LCD screen, Samsung, IBM LCD screen, NEC LCD screen, Acer, Fujitsu, HannStar LCD screen, HannStar LCD screen, Hosiden LCD screen, Hyundai LCD screen, Sharp (Sharp), Toshiba (Toshiba).
Manufacturer of TFT-LCD:
Japan and South Korea: Sharp (SHARP), Hitachi, Sanyo, Samsung (SAMSUNG), Lg.philips LCD (LGL) Taiwan, China: AU Optronics (AUO), Chi Mei Electric (CMO), CPT (CPT), Yu Yucai晶(HANNSTAR), 元太(PVI) China: BOE, TMA TFT-LCD driver IC manufacturers: Japan and South Korea: RENESAS, SAMSUNG, EPSON Taiwan: ITE力(ILITEK),矽创(ST), 奇景(HIMAX),æ—耀(ORISE),SOLOMON, ULTRACHIP,NOVATEK
LCD: HannStar, Ling Giant, TP: Vision (Rivv Optoelectronics)
FPC: Sancha Crown, Glyn (SMT), Xinan, Anyuanda, Fusheng. Polarizer: Anxun
Electronic components: Shengbang Electronics, Ouyada. Glue conductive cloth: Heli products
ACF: Asia's first (SONY), Qi Feng Technology (玮锋)
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