Research Of GI Wireless Endoscope System Based On MEMS

Marking up the central portion of the gastrointestinal (GI) tract, the small intestine cannot be entirely inspected by current flexible GI endoscopes. Other traditional examining methods cannot satisfy the demands of clinical diagnosis due to their low sensitivity and reliability. On the other hand, wireless endoscopes are capable of eliminating the limitations of conventional GI endoscopes. Subminiature camera capsule could be swallowed into the intestine to take photographs of specific and non-specific locations of the gullet, stomach, large and small intestines. This is a great advantage over traditional endoscopes, which can only examine the upper and lower GI tracts. This examining method is noninvasive and painless, which is in line with recent trends towards noninvasive and minimally invasive therapy.The thesis firstly gives a survey about the research progress of MEMS technology and gastrointestinal endoscopy. Miniature wireless endoscopic capsule consists of three parts: wireless camera-capsule, wireless image signal transmission set and video-browsing workstation. The MEMS technology affords a good approach to the miniature of wireless endoscopic capsule. Due to lack of reference data, several plans are designed by me for each part of the system and an optimal solution is implemented by considering all kinds of factors. The main achievements of the project include: (1) A prototype of wireless endoscopic system has been designed and manufactured. The animal trials have been performed in a pig's intestine and the photos of intestinal wall have been acquired successfully. (2) Wireless camera-capsule must be miniature and low power consumption. Under the condition that the image sensor, which can meet all technical parameters for the capsule, can't be purchased and ordered, the image sensor OV7930N that satisfies the basic demands is chosen as the component. However, OV7930N's size is too big and its power consumption is too high. To solve the problem, the image sensor chip is firstly incised by laser and picked out from the component's base; then it is processed by MEMS technology and finally a miniature camera circuit module is built by think film technique. In the project, button cells are adopted for power supply for they can work in the condition of micro current. In order to decrease the power consumption from OV7930N, a novel power management circuit, which works at off-and-on mode, is designed to supply the camera capsule. The circuit uses a rise and steady voltage module lf1751-5 as electronic switch and uses MSP430x11x1...