Ultrasonic sensor
US8166824B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Apr 16, 2009 |
| Grant date | May 1, 2012 |
| Priority date | — |
| Expiry date | May 8, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01S2015/939
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An ultrasonic sensor includes a transmitting device, a receiving device, and a circuit device. The circuit device determines that the receiving device receives an ultrasonic wave reflected from an object, when an output voltage of the receiving device is equal to or greater than a first threshold. The circuit device includes a humidity detection section configured to detect an ambient humidity of the transmitting and receiving devices and a threshold adjustment section configured to calculate, based on the detected ambient humidity, a sound pressure of the ultrasonic wave that is received by the receiving device after propagating over a round-trip distance between the ultrasonic sensor and the object. The threshold adjustment section reduces the first threshold, when the output voltage corresponding to the calculated sound pressure is less than a second threshold that is greater the first threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.