LIGHT DETECTING DEVICE

• US 20100102212A1
• Filed: 10/26/2009
• Published: 04/29/2010
• Est. Priority Date: 10/29/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: SAIKI, Katsuhiro
• Granted Patent: US 8,389,966 B2
• Time in Patent Office: Days
• US Class Current: 250/227.110
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0204 Compact construction
• CPC Class Codes: G01J 1/0271 Housings; Attachments or accessories for photometers
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0407 Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
• CPC Class Codes: G01J 1/0411 using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction
• CPC Class Codes: G01J 1/0414 using plane or convex mirrors, parallel phase plates, or plane beam-splitters
• CPC Class Codes: G01J 1/06 Restricting the angle of incident light

Abstract

A light detecting device includes a case, a reflector, and a light receiving element. The case is fixed to a windshield, and outside light passes through the windshield and an entrance hole defined in the case. A predetermined light travels from a predetermined area, and the reflector reflects the predetermined light of the outside light. The light receiving element is disposed in the case to have a distance from the windshield, and the distance is larger than a distance between the windshield and the entrance hole. The light receiving element receives the reflected predetermined light.

Claims

1. A light detecting device comprising:

a case to be fixed to a windshield, outside light passes through the windshield and an entrance hole defined in the case;

a reflector to reflect a predetermined light of the outside light, the predetermined light traveling from a predetermined area; and

a light receiving element disposed in the case to have a distance from the windshield, the distance being larger than a distance between the windshield and the entrance hole, wherein

the light receiving element receives the reflected predetermined light.

2. The light detecting device according to claim 1, further comprising:

a circuit board to which the light receiving element is mounted, wherein

the case has a first wall having the entrance hole, and a second wall connecting the first wall and the circuit board, and

the reflector is a plane mirror arranged on the second wall.

3. The light detecting device according to claim 1, further comprising:

a circuit board to which the light receiving element is mounted, wherein

the case has a first wall having the entrance hole, and a second wall connecting the first wall and the circuit board,

the reflector is a concave mirror arranged on the second wall,

the concave mirror gathers the predetermined light to the light receiving element.

4. The light detecting device according to claim 3, wherein

the concave mirror is arranged on a curved face of the second wall.

5. The light detecting device according to claim 1, further comprising:

a light guide made of a transparent or translucent material, wherein

the light guide has

an entrance face to which the predetermined light is incident,

a reflecting face to reflect all of the incident predetermined light, and

an exit face to emit all of the reflected predetermined light to the light receiving element, and

the reflector is the reflecting face of the light guide.

6. The light detecting device according to claim 5, wherein

the reflecting face of the light guide has a curved shape to gather the incident predetermined light to the light receiving element.

7. The light detecting device according to claim 5, further comprising:

a circuit board to which the light receiving element is mounted, wherein

the case has a first wall having the entrance hole, and a second wall connecting the first wall and the circuit board, and

the reflecting face of the light guide has a protruding shape fitted to a recess defined in the second wall.

8. The light detecting device according to claim 5, wherein

the entrance face of the light guide is inclined to extend from an end of the reflecting face toward a normal line of an approximately center part of the reflecting face, and

the incident predetermined light has an angle larger than a critical angle of the reflecting face.

9. The light detecting device according to claim 5, wherein

the entrance face of the light guide has a curved concave shape.

10. The light detecting device according to claim 5, wherein

the entrance face of the light guide has an angle relative to the first wall having the entrance hole,

the angle is approximately equal to an inclined angle of the windshield relative to a horizontal direction, and

the predetermined light includes light traveling in an approximately vertical direction.

11. The light detecting device according to claim 1, further comprising

an optical sensor to detect raindrop, wherein

the optical sensor is arranged on an upper area of the case in a vertical direction.

12. The light detecting device according to claim 1, further comprising:

a rain sensor arranged in the case, wherein

the reflector is disposed on an inner wall of the case, and

the rain sensor is located to oppose the reflector.

13. The light detecting device according to claim 1, further comprising:

a screen board to restrict other light different from the predetermined light from being transmitted to the light receiving element.

14. The light detecting device according to claim 1, wherein

the predetermined area is defined to have an axis and a predetermined angle relative to the axis, and

the predetermined area corresponds to a viewing range of the light receiving element.

15. The light detecting device according to claim 14, wherein

the axis is defined to have a predetermined angle relative to a normal line of the windshield.