PRESSURE SENSOR, TRANSMITTER, AND TIRE STATE MONITORING DEVICE

摘要

PPROBLEM TO BE SOLVED: To provide a pressure sensor capable of accurately measuring pressures and contributing to a reduction in size and weight of a transmitter, the transmitter having the pressure sensor, and a tire state monitoring device having the transmitter. PSOLUTION: A first electrode 101 is formed on the upper surface of an upper pedestal 100 to cover a diaphragm 103. The first electrode 101 on the upper pedestal 100 is connected to Vdd (+3 V) or GND (0 V) of a battery 35 through a lead wire 300 and a power pattern on a substrate 80. Accordingly, the potential of the first electrode 101 on the upper pedestal 100 is maintained at the same potential as that of the battery 35. As a result, the pressure sensor 32 is shielded by the first electrode 101. Thus, the pressure sensor 32 is hard to be affected by an electromagnetic field from the outside, and a pneumatic pressure in a tire can be accurately measured. PCOPYRIGHT: (C)2004,JPO&NCIPI