Study On The Driving And Controlling Circuit Of HMD Based On LCoS

Head Mounted Display(HMD) is one kind of typical microdisplay, and its application prospect is very broad. Liquid Crystal on Silicon(LCoS)is a new reflective microdisplay with many advantages, such as a large screen,high brightness,high resolution and low power dissipation as well., and it is very suitable to be used in microdisplay systems, especially in HMD. People began to research HMD from 1960s. Many universities of the world is concentrating on researching it now. And there are more than forty companies that product and sale HMD, and most of them are in America, Europe and Japan. And the researchers on LCoS are mostly American and English companies. Chip's design and making and the integrating of optical system are all related in the LCoS chip system. The research on LCoS driving circuit and the design of controlling circuit will contribute to the design of microdisplay system, especially to HMD. It will contribute to the design of microdisplay chip with our country's knowledge right. The overall introduction of the driving and controlling circuit is given first, the thorough research and the preliminary design of the driving circuit and the controlling circuit is separately actuated. This paper does a lot of research on HMD, LCoS and FPGA. 1) this paper introduces the concept and the history of HMD and LCoS. As well, the basic knowledge of LCD is introduced. Then the driving and controlling circuit of HMD based on LCoS is described generally. 2) As there are some disadvantages in the common driving method of LCD, a new low voltage driving method is introduced and chosen. The structure and working principle of low voltage driving circuit is described generally. Its components are described in detail also. 3) The design of dirving circuit is seperated two parts. One of them is the design of circuit diagram. The other part is programming FPGA. Following, the key questions in the design of the controlling circuit are discussed. The requirements of the controlling circuit are analyzed. Then this paper designs the structure of the circuit and makes the choice of the parts of an apparatus. The hardware system's design is accomplished. At the same time, the function of FPGA programming is analyzed. Based on the theory of modularization, the whole software system is divided into some sub-modules. Aiming at the core of the controlling circuit——the realization of FSC, the detailed and feasible method is given. In conclusion, a new low voltage driving method is analyzed and a feasible controlling circuit is designed. Now, the research on HMD is just underway. The method of driving LCD in the low voltage with common electronic field inversion voids the pixel voltage's self hoist effectively and makes the driving voltage work below the CMOS standard voltage. At the same time, a controlling circuit including hardware and FPGA programming is designed. This paper's work makes a great many preparations on the design of HMD, and contributes to the production of LCoS chip of our own country.