Patent ID: 8176776

Claim:
A tire pressure detection system comprising: a tire pressure detection device, mounted inside a tire of a vehicle, for detecting air pressure inside the tire; and a reader having a coil antenna having an opening surface directed to the tire, and mounted in a highest portion of a wheel housing of the vehicle, wherein the tire pressure detection device comprises: a pressure sensor for measuring the air pressure, using a displacement portion to be displaced according to the air pressure; and a circuit board having a response circuit mounted on a board surface thereof, the response circuit for sending, through interaction with a supply electromagnetic field applied from the reader, data measured by the pressure sensor to the reader, wherein: the pressure sensor is mounted on the circuit board such that a displacement direction of the displacement portion is set parallel to the board surface, the circuit board is attached on a tread portion of the tire or a rim portion of a wheel on which the tire is mounted, such that a displacement direction of the displacement portion is set parallel to a rotational axis of the tire, and the response circuit has a coil all of which is formed as a wiring pattern on the board surface, and is electromagnetically coupled with the coil antenna to transmit the measured data.