Research On Electronic Signal Processing And Control System Of The Non-contact IOP Measuring Instrument Based On Interferential Laser

Glaucoma is one disease which can make the eye be blind, often called "lurk killer". For these reason, many developed country, especially US and Japan had done some research work on intraocular pressure(IOP) measurement. Now, the people widely adopt the contact measurements, but these kinds of measurement make the patient uncomfortable, and the patient need anaesthesia. At the same time, it can bring the infection among the patient. It is very un-convenient. Due to this, many country had developed some non-contact measuring technologies, but the instruments based on these technologies are very complex, costliness and restrained. In order to research the instrument which has the advantages of high precision, simple configuration, low cost and convenient for popularization, we had designed a new measuring system: the non-contact measuring system based on the interferential laser. It mainly based on interferential laser fine technology which can reduce pain and infection, and could not make intraocular heavily shaped. Besides the laser we used is very faint which could not make damages to our eyes, and had been tested could not make uncomfortable, according to the standard of sanitation organization. In this measuring system design, we use 8051 MCU as main control part that can harmonize other parts, such as LCD display, pulse generating and pulse counting; pulse stream generator design is a key and hard technology in this system design. We use CPLD as pulse distributor so that motor movement can drive piston pout pulse stream, and the above design had been tested has good performance. The difficulty of the electronic system design lies in the laser is very faint for being photodetected, known as 10-6~10-9W.After lots of test, we bring forward a new design of the photoelectricity system, it has the advantages of both reduce the noise and magnify the signal. Among this, ellipse type filter can reduce the beyond band noise very well. At last, through the performance test and results analysis, primary experimental results indicates that the project useing the method of non-contact IOP measurement based on laser interference to measure IOP should be feasible, and are turning into mature. This task is the content of the project sponsored by Nation Natural Science Foundation, therefore, To solve this task well is the basis of the accomplishment of the project sponsored by Nation Natural Science Foundation.