Abstract: The present invention provides a pressure detector capable of easily responding to changes in the specification. The pressure detector that the sensor unit 11 for detecting pressure and the electronic parts 35 and 36 for reducing electrical disturbance are electrically joined to the exposed part 24 of the lead material of the opening 28 of the external case 28 and the thermoset resin 38 is injected and set in the opening, thus the members are fixed can be obtained. An external electronic part for compensating for the transient voltage resistance and electromagnetic failure resistance of a single one-chip semiconductor sensor can be mounted and the cost can be reduced by miniaturization, lightweight, and reduction in the assembly man-hour.

Abstract: A three-dimensional acceleration sensor capable of detecting a small acceleration value and even an acceleration value amounting up to 100 G occurring in the event of a collision has a diaphragm for linking a frame and a massive part, and diaphragms and beams for linking the massive part and a central part. These elements are formed by working a single crystalline silicon plate. Gaps between the massive part and opposing electrodes are changed by acceleration applied to the massive part. A circuit connected to terminals detects the changes in gaps as changes in capacitances and determines direction and level of the applied acceleration.

Abstract: A three-dimensional acceleration sensor capable of detecting a small acceleration value and even an acceleration value amounting up to 100G occurring in the event of a collision comprises a diaphragm for linking a frame and a massive part and diaphragms and beams for linking the massive part and a central part. These elements are formed by working a single crystalline silicon plate. Gaps between the massive part and opposing electrodes are changed by acceleration applied to the massive part. A circuit connected to terminals detects the changes in gaps as changes in capacitances and determines direction and level of the applied acceleration.

Abstract: A method of manufacturing structures such as a pressure gauge, an accelerometer and the like with a single crystal material such as silicon uses etching techniques where the shape of a part subjected to stress concentration has a curvature, another part is formed in a plane body and a polyhedron is constituted by combining both.To attain the above constitution, a wafer of single crystal material is formed with a stepped surface having a value corresponding to at least the depth of the curvature in a first anisotropic etching process using a prescribed etching mask, and in a second anisotropic etching process, an etching mask is used by removing at least a part of the etching mask used in the first anisotropic etching process.