Weak current College】 【LCD display principle and application of knowledge quiz.

<br> FAQ for customers using LCD problems encountered in the process of classification and summary will causes of the problem and the solution for a detailed analysis and answers. You use if not solved, please refer to the relevant category, it might be helpful to .you. <br> <br> Principles and applications of LCD display <br> <br> The difference between Q: LCD and LCM? <br> A: LCD: LiquidCrystalDisplay LCD; LCM: LiquidCrystalModule LCD module (including components) <br .> Q: LCD interface forms several? <br> A: main LCD display interface is divided into two kinds: CMOS / TTL interface and LVDS (low voltage differential signaling LowVoltageDifferentialSignaling) <br> Q: How do I interface to drive longer distance ( .about 10m)? <br> A: to make the LCD display, long distance driving some difference driving mode can be recommended. Two common difference technology are low-voltage differential signaling LVDS (LowVoltageDifferentialSignal) and step minimized differential signaling TMDS (LowVoltageDifferentialSignal). .Are as long as you use a dedicated send / receive chip to transmit signals. Even if only the 25MHz clock VGA display mode, use the ribbon cable by long distance transmission of high speed digital signal is also very difficult. <br> Q: to .avoid signal blocking, consider giving the LCD module's power-up sequence, LP or CLK more key, or if you want to also consider VCC power or sustained not show sufficient length of time, still no LP, CLK signal? <br> A: .to avoid blocking, the most important thing is to remember the "do not enter the VCC before any signal." All signal are the same, including scan control pins, each signal must comply with the timing requirements. <br> Q: is contrary .to the power-on sequence on all display the same consequences? <br> A: No. Different display on power-up sequence of sensitivity is not the same. <br> Q: what is bias? <br> A: STN LCD .general need bias and operating voltage. Adjustable bias can change the contrast and perspective. <br> Q: when the temperature changes, view change? <br> A: for STN display mode, outside the temperature range, the contrast will change. You .can adjust the bias for compensation. <br> Q: can you give just glow display module for 5V? <br> A: No. The risk will be blocked. <br> Q: manual on to VCC can to 6V (or 7V .). Why is added only to 3.6V? <br> A: operating voltage and maximum voltage is different, is to ensure that the work of 3.6V voltage, 6V said guarantee will not be damaged. <br> Q: LCD display temperature .? <br> A: low-temperature viscosity smaller when the LCD, the response time. For TFT displays, each point is a transistor direct drive, the impact of relatively small. But for STN display, 0 ° c response time will be up .to 4 seconds. <br> Q: when the temperature is below the LCD provides working temperature, display? <br> A: the response time will slow, contrast, cold cathode backlight lamp life may also reduce dramatically the backlight does not light up .. <br> Q: when the operating temperature is higher than the operating temperature LCD displays? <br> A: response time reduced contrast affected. Some IC of noise would exacerbate, DC-DC transform will drift, Polaroid will be affected. < .br> Q: STN display bright local than other regions, why not? <br> A: most of the heat, such as backlight, the light of the Sun. <br> Q: what is permanently damaged? <br> A: .physical damage is permanent. <br> Q: sunlight can damage the LCD display module? <br> A: there are two potential problems: heat and light (including visible and ultraviolet light). Sunshine (greenhouse effect) is heated to show portion .of the ambient temperature. STN display particularly sensitive. Also, do not use Polaroid exposure under ultraviolet light is too long. Ultraviolet radiation is very easy to use goggles shielding. In some applications (such as a preset protection highlight backlight module) may cause the .LCD to the photoelectric effect transistor might be affected by the invasion of light and color. <br> Q: LCD emits harmful rays? <br> A: LCD does not issue any rays. But there is a low-frequency electric field, the .backlight will need about voltage 50KHz. <br> Q: LCD, need more straight? <br> A: setup the more flat LCD is better. Liquid crystal cell is glass encapsulated, not deliberately bent. Due to external forces and distort the resulting .liquid crystal cell gap between LCD discoloration caused by changes or contrast changes. <br> Q: what are the recommended seismic equipment? <br> A: any LCD deceleration of mechanical systems. To make the LCD system with external enclosure isolation is highly desirable .. <br> Q: for LCD front surface pressure (such as finger pressure on it), the LCD will easily be damaged? <br> A: of course it should be avoided, but also not easy to damage the LCD, the pressure .will damage the LCD. <br> Q: LCD front surface can easily be scratched? <br> Surface hardness A: LCD generally very easily 3H, the sharp weapon of scratches. <br> Q: If you do drop test, the most .vulnerable in the LCD is which part? <br> A: most easy cold cathode fluorescent tube is damaged. Then the edge of the LCD, prone to cracking. <br> Q: LCD perspective is what? <br> A: General or .so is symmetric and asymmetric. Passive matrix (STN) display angle smaller, TFT liquid view larger, wide viewing angle technologyWith up and down, left and has done all 170 ° angle of view, see the instruction manual. <br> Q: why .does my STN screen edges appear brighter than the Center? <br> A: it may be two reasons: one is at the edge of the cell gap and the Centre region, the second is due to the backlight lamp heating enable edge local and other .regional differences. <br> Q: How do I measure the brightness? <br> A: in backlight lights up after 30 minutes, in fully measured brightness baitai. <br> Q: how many ordinary LCD allows a bad points? <br .> A: because of the screen. LCD without international testing standards, each screen to follow the enterprise standard. <br> Q: LCD MTBF (non-fault time)? <br> A: typical TFT-LCD approximately 100, 000FIT, .so its about 100K hours MTBF (not including backlight). <br> Q: what is a CGS (continuous grain boundary SI)? <br> A: CGS is SHARP utilizes a new functionality, and performance in essence with Mono to match the .growth of "solid phase to form the LSI technology". Through this process, the CGS enables Silicon grain boundary in atomic-level maintain continuity, so electronic semiconductor in velocity can be a structure of amorphous silicon TFT 600 times, is the low-temperature .polysilicon for 4 times. This technology can be a digital circuit can be fully integrated with the LCD display, the display of a fine. <br> Q: ASV represent? <br> A: ASV does not mean anything. SHARP start enabled ASV .represents the next generation of display technology, the technology including pure black, wide angle and extremely fast response times. <br> Q: LCD display is a complete subsystem? also need other accessories? <br> A: the General need for driving Backlight .Inverter, display controllers and cables, etc. <br> <br> LCD controller selection and use of <br> <br> Q: common LCD control programme which kind? <br> A: General LCD control programme is divided into three main .categories: MCU interface controller, multimedia interface controller, built-in flat panel controller (ARM, IPC), see the website of the "solution". <br> Q: the advantages and disadvantages of different control scheme? <br> A: .◆ MCU bus control: <br> Benefits: low cost, mature technology, easy to use. <br> Disadvantages: feature simple, limited to low-and medium-resolution, product upgrade transplantation is not convenient. <br> ◆ ARM programme .: <br> Advantages: less direct control of the sectors, easily portable. <br> Disadvantages: high technical threshold, limited to low resolution <br> ◆ IPC inline display control: <br> Advantages: less direct control of the sectors, .simple to use. <br> Disadvantages: TTL signal transmission distance limited, replace the display, the upgrade is not convenient, currently limited to small and medium resolution. <br> ◆ Multimedia interface control programmes (PC & Video interface): < .br> Advantages: suitable for multimedia display interface, easy to use and flexible, transplantation, control range. <br> Disadvantages: PC interface methods to increase links and increase costs for non-standard signals to adapt slightly more difficult. Does not apply to .STN liquid. <br> Q: I am using to control the TFT-LCD ARM7, your company has the appropriate controller? <br> A: our company MCU interface controller can control the 800 × 600 TFT-LCD below. The data available .through 8Bit ARM7 and mouth directly control the control display, simple operation. <br> Q: If you want to control labor, what needs to be done TFT-LCD work? <br> A: ◆ determine your LCD types, such as resolution ., etc.; <br> ◆ Determine the IPC Board supports this your choice of LCD, whether you have the appropriate BIOS; <br> ◆ Identify LCD interface between the IPC and to make appropriate cables; <br> ◆ Power-debug, .such as displaying a few abnormal (excluding cable problems), and industrial manufacturers contact BIOS modifications accordingly. <br> Q: IPC cannot directly control TFT-LCD? <br> A: if IPC provides VGA signal available through our multimedia interface controller transfer .control TFT-LCD. <br> Q: multimedia interface controller can control SHARPLQ057? <br> A: can, because SHAPPLQ057 resolution is 320 * 240, but can receive the signal of 640 * 480, so using the PC interface controller LQ057 can .only display signal 1 / 4 <br> Q: multimedia interface controller supports input signal? <br> A: to support the input signal: PC (VGA input), composite video, S-video, component video, etc. <br> .Q: multimedia interface controller with picture in picture feature? <br> A: Yes, and you can realize the picture in picture, picture, painting, multi-picture display. <br> <br> Backlight and driving <br> <br .> Q: what is the VSI? <br> A: inverter is to convert the DC voltage to AC voltage for driven backlit (cold cathode fluorescent lamp CCFL backlighting) circuit. <br> Q: how to look for suitable inverters? <br .> A: * start voltage: cold starting address <br> ◆ Power: test load impedance and CCFL load impedance, load impedance small means less power, inverter capacity <br> * Current: inverter complies with the maximum output current CCFL typical requirements < .br> ◆ The working frequency: CCFL requirements, while not interfering with other circuits <br> Q: inverter usage considerations? <br> A: * Security: to prevent electric shock and fire. <br> ◆ Security measures: install avoid short .circuit, ensure safe electrical distance (> 2mm). <br> ◆ Input is connected properly, especially the Vin and GND; enter in the allowable range. <br> ◆ Output not connected backwards may cause a heavy load. <br> .◆ Output connection to can *, gap may lead to discharge, or CCFL is off, or Flash, etc., can also cause inverter temperature rise. <br> ◆ From the inverter to the CCFL's connector should be as short as possible, the .wiring form parasitic capacitance: a. shorten the life of CCFL, b. decreasing the brightness CCFL, c. dropped to start voltage after CCFL. At the same time output line equivalent to the antenna, easy-to-radiation. No need to extend .the line, you should use high pressure of the wire. <br> Q: LCD module backlight cable if you want to lengthen can cut? if not, what measures should be taken? <br> A: you cannot cut. If you want .to lengthen the backlight cable to use with a matching connector for high-voltage wiring. <br> Q: backlight extension cords on brightness, life has no effect? <br> A: there are affected. From the inverter to the CCFL's connector should .be as short as possible, the wiring form parasitic capacitance: a. shorten the life of CCFL, b. decreasing the brightness CCFL, c. dropped to start voltage after CCFL. At the same time output line equivalent to the antenna, easy-to .-radiation. No need to extend the line, you should use high pressure of the wire. <br> Q: if to STN display module backlight lamp for current higher than the rated current of what results? <br> A: 1) lamp .life will vary according to the current increase in proportion and shortening; 2) near the tube Department of contrast changes, resulting in uneven phenomenon. Because current increases, heat lamp, STN technology for heat-sensitive, and the resulting contrast changes. <br .> Q: if to TFT display module backlight lamp for current higher than the rated current of what will be the consequences? <br> A: 1) lamp life will vary according to the current increase in proportion and shortening; 2) near the tube .Department of contrast slightly change will occur, resulting in uneven, but far from STN class display module so obvious. <br> <br> <br>.