Study On Driving System Of Micro-LED

The Micro-LED has the advantages of LCD and OLED,such as independent illumination,high resolution,long life,fast response,high contrast,and has promising application in flexible and transparent display.Therefore,it is expected to be the leader of the next generation of displays.However,there are still many problems in the current Micro-LED display technology.The biggest one is the transfer of a large number of tiny LED chips,and the electrode bonding between chips and CMOS(or TFT)backplane.Because that micro-LED are current-type devices with high integration densities,they are easy to generate a lot of heat that cannot be dissipated.In addition,the driving method of traditional large LED screen by using a large number of row and column driver chips is not suitable for Micro-LED display,because it not only occupies a large area and has poor heat dissipation capability,but also requires a large rear-stage driving system.In view of the above problems,the corresponding solutions are researched and proposed in this work.First of all,a non-transfer and non-bonded design method for high-density MicroLED display is proposed,which avoids the transfer and bonding process and improves the reliability of display preparation.In this method,display array,metal wiring,and driver are directly integrated on sapphire.The fabrication process are presented as follows: Firstly,an optimized design of the process layout is made to improve the proportion of the effective display area and to simplify the design of the PCB at the latter stage.Then,the Micro-LED display array and the PN type metal trace are fabricated based on the layout of the design.Finally,the hot pressing between the driver chip and the display screen is completed by using a high-precision instrument.The display screen is characterized after the preparation.Secondly,a high-integration driver chip and power control method are used to fabricate a driving system,which optimizes the use of the row and column driver chip and improves the heating problem of the display.For hardware design,a highly integrated driver chip that has similar driving and electrical characteristics to MicroLED is used to drive the display.The system applies a purely digitally transmitted DVI interface to capture video source data from the PC terminal and to realize interception of image selection,high-speed conversion of gradation,and timing control through the powerful FPGA processor.For software system,taking advantages of the fast response and high brightness of Micro-LED,a heat dissipation frame module is specially designed to improve the heating problem of the display.The experimental results show that the non-transfer and non-bonded method proposed is simple and feasible.A 128×128 pixel,508 PPI Mico-LED display has been successfully prepared,which has great application value in high-density Micro-LED display.The drive system designed in this paper can realize 16 grayscale video image display of the display screen.Moreover,the high-resolution driver chip greatly simplifies the rear-stage drive system.The thermal frame module designed in this paper can reduce the temperature of the display by nearly 10 °C under the same conditions,and has good heat dissipation capability.