Tunnel sensor
US6243002A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 1999 |
| Grant date | Jun 5, 2001 |
| Priority date | — |
| Expiry date | Mar 31, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB60Q2300/337
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A sensor (20, 100, 200, 300) for detecting the approach and exit of a vehicle (42) to a tunnel (46). In one embodiment there is a sensor (20, 100, 200, 300) with a photodiode (22a) that receives light through an inclined channel (30, 30') or aperture (32, 332, 432). The channel provides a field of view (44, 344, 31) ahead and above the vehicle. The photosensor (22a) is thus sensitive to the change in light from this field of view (44, 344, 31) as a vehicle enters (46a) and exits (46b) a tunnel (46). Some embodiments of the present invention include a second photosensor (22b) with a wider field of view (112, 112", 111) for detecting ambient light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.