Method for stabilizing output of rain sensor and protection method therefor
US6397161B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 1998 |
| Grant date | May 28, 2002 |
| Priority date | — |
| Expiry date | Dec 16, 2018 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60S1/0866
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A rain sensor including light emitting means 7 for guiding light into a window glass so as to undergo total internal reflection within the window glass, light receiving means 8 for receiving the light which has undergone total internal reflection within the window glass, and means for detecting the amount of water drops adhered to or present upon the window glass so as to output a driving signal to a wiper driver apparatus 20, a difference signal corresponding to a difference between a preset reference value and an output signal of an amplifier circuit 17 of the light receiving means is fed back to the amplifier 17, and an amplification factor of the amplifier circuit 17 is adjusted so as to maintain the output signal thereof at a constant value irrespective of the operation condition of the wiper, when electrical power is applied to the rain sensor 2. Furthermore, in a protecting method for the rain sensor 2, a driving current fed to light emitting element 10 is measured and converted into an ambient temperature, and a driving current supplied to the light emitting element 10 by the driver circuit 12 is stopped when the converted value is outside a preset temperature range, by tur…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.