The Circuit Design And Test Platform Research Of TFT-LCM Used In Handphone

With the development of the microelectronic technology and materialsindustry, the image display technology has developed quickly.Lots of newmodels Flat Panel Display (FPD) have appeared.The display quality of FPD isclosed to traditional Cathode Ray Tube (CRT) display,and some of them arebetter.At the same time, FPD also meets the expectations of small size andlow power.Now,color Thin-Film Transistor Liquid-Crystal Display(TFT-LCD) is one of FPD that has the best prospect in application.Medial,small-size products used in cell phones that require a high degree of integration driver chips,and in order to reduce power consumption and increase life expectancy,low voltage is required. The past two years,TFT(thin film transistor) LCD which meets these requirements has to enter the market,thus replacing the TN, CSTN LCD,as a leap forward in liquid crystal display technology. At present, TFT-LCD is moving forward to high-resolution,full-color, and thin shape direction.With the rapid development of TFT (Thin Film Transistor) array drive liquid crystal display technology,the improvement of manufacturing process and reduced costs.And since the thin film transistor arrays directly to drive liquid crystal elements,the cross-distortion effects eliminate;and with the use of low viscosity liquid crystal materials,response speed have greatly improved to meet the needs of becomes one of the most promising display technology in the 21st century.The application of small-size TFT-LCD gradually expand,especially the liquid crystal display module used in cell phone products whose driven chip has a high level of integration,low voltage,low power,quick speed,have promoted the application of the TFT-LCD more and more.At present mobile phone display market,1.76inch TFT-LCD has become main stream products.The developer usually use HITACHI HD66789 as 1.76inch TFT-LCD'Driver IC,although the performance of the IC has stable performance and mature technology,However,the cost is very high, which makes the high cost of LCD module,and can not fit the development of market.RENESUS introduced a model of the Driver IC R61505U,has a higher low-cost compared with HD66789 . Thus,to establish a model program based on this IC,and to produce samples for the promotion of the demonstration,the market can be of great effect. This is the purpose of this topic.1.General system planAimed at the R61505U Driver IC,we design the TFT-LCM using the imbedded crystal oscillator circuit and VCOM, the inner-outer circuit.When J600 test systems development work completed,we use this platform to test module.From test results, it shows well and have color saturation and picture stability,without flicker,IC stability.After reliability testing,the results still showed good performance and it can meet customer'requirements.This shows the stability performance of R61505U DriverIC which can complete 1.76inch TFT-LCD driven work.In addition, the high cost performance of this IC, ccupy a favorable condition for the future market.On the subject, established a complete test system. ave designed and completed J600 test system and completed the test the 16 bits parallel interface to 1.76inch TFT-LCM. Test results showed the gray-scale tests can meet the high demand, product stability, thus laying a sound technological foundation on expanding the domestic market in the future.In view of the development requirements of the company,we want to develop a portable DEMO box using LPC2138,its small size, light weight can perfume our products and provide a fast,efficient manner for the customers to understand the company's products,it can fully reflect the company's products performance,which reflect the company's strong R & D teams,and technology. This DEMO box will certainly be well received.Meanwhile I am working to produce a platform for the research and development of DEMO for the company.2.The main work of this topicThe main topic of this work are as follows: (1)Based on the TFT-LCD driver principle Driver IC and R61505U information research,design 1.76inch TFT-LCD module.Basing on the technology and principle of TFT-LCM,1.76inch TFT-LCMwas designed with R61505U LCD controller integrating gate driver andsource driver. According to the adjustment of VCOM,two circuits weredesigned.One was adjusted by built-in register, and the other was adjusted byexternal variable resistor.(2)Establishment of the company's test system ,using the J600 processor to design test machines and work on the module testing aimed at 16 bits and parallel interface of 1.76inch products;TFT-LCM was tested by line inversion mode under the condition ofalternant VCOM voltage,after the sample was made by COG and TAB craft.J600 processor testing system was designed to test the sample in 16 bitsparallel interface.While J600 testing system can't do. The LCM displayed excellent effect in the test.(3)Research and design the DEMO for1.76inch project using the LPC2138 chip and double module demonstration system .The cascade demo was designed using LPC2138 processor with built-in512Kb flash.In contrast with the old DEMO, it was not only small size, but also can simulate and download on line, and show the performance of TFTLCM conveniently and effectively.