ULTRA MINIATURE PRESSURE SENSOR AND GUIDEWIRE USING THE SAME AND METHOD

摘要

This invention is a guidewire (21) having pressure sensing capabilities for measuring pressure of a liquid in a vessel comprising a flexible elongate member (41) and having proximal (42) and distal (43) extremities, and having an outside diameter of 0.018'' or less. The distal extremity of said flexible elongate member (41) is adapted to be disposed in the liquid in said vessel. A housing (51) is carried by the flexible elongate member (41) and has a diameter substantially the same as the diameter of the flexible elongate member (41). The housing (51) has a space therein with a pressure sensor (76) mounted in the housing space in the housing. The pressure sensor (76) has a diaphragm (79) formed in a crystal (77) of semiconductor material, that is sensitive to changes in pressure of the liquid in the vessel. The diaphragm (79) is rectangular in shape and is mounted in a well (84), and is bordered by a rim (86) surrounding the well (84). A backing plate (78) is formed of an insulating material bonded to the crystal (77) and serves to reinforce the rim (86) of the crystal (77). The backing plate (78) has a cavity (101) therein underlying the diaphragm and is in substantial registration with the diaphragm (79). The cavity (101) serves as a pressure reference.