| 摘要 |
<p>A thin diaphragm (22) receives pressure across one side and faces a beam splitter (25) on the other side. The beam splitter (25) is integrally attached to the diaphragm (22) and serves as a local optical reference plane for the entire assembly. A small cavity (40) is formed between the diaphragm (22) and beam splitter (25). Coherent light from a light source (49) is partially reflected at the beam splitter (25). The remainder of the light is reflected from the diaphragm (22). The reflected beams recombine at a detection point and form an interference pattern. The phase difference between the reflected beams is a function of the amount of deflection of the diaphragm (22). The interference pattern being indicative of the deflection of the diaphragm is received by a light detector (34). Optical calibration of the assembly is a function of the distance between the diaphragm (22) and beam splitter (25) which remains as predefined because the beam splitter (25) is integral with the diaphragm. A vent (28) in the small cavity enables the diaphragm (22) to sense small pressures with increased sensitivity. Fiber optics enable use of the assembly in high temperatures.</p> |
