Light sensor configuration

• US 6,943,342 B2
• Filed: 05/25/2004
• Issued: 09/13/2005
• Est. Priority Date: 01/10/2002
• Status: Expired due to Term

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Bechtel, Jon H., Ockerse, Harold C.
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US10/853,541
• Publication Number:
  US 20040217266A1
• Time in Patent Office: 476 Days
• Field of Search: 250/239, 250/216, 250/214.1, 250/208.1, 359/603, 359/601, 359/602, 359/229, 359/230
• US Class Current: 250/239
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: B60R 1/12 Mirror assemblies combined with other articles, e.g. clocks
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: B60S 1/0885 the sensor being integrated in a rear-view mirror module
• CPC Class Codes: G01J 1/02 Details
• CPC Class Codes: G01J 1/0209 Monolithic
• CPC Class Codes: G01J 1/0219 Electrical interface; User interface
• CPC Class Codes: G01J 1/0228 Control of working procedures; Failure detection; Spectral bandwidth calculation
• CPC Class Codes: G01J 1/0266 Field-of-view determination; Aiming or pointing of a photometer; Adjusting alignment; Encoding angular position; Size of the measurement area; Position tracking; Photodetection involving different fields of view for a single detector
• 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 1/0403 Mechanical elements; Supports for optical elements; Scanning arrangements
• 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 1/0422 using light concentrators, collectors or condensers
• CPC Class Codes: G01J 1/0474 Diffusers cavities G01J2001/0481
• CPC Class Codes: G01J 1/18 using comparison with a reference electric value
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01J 1/46 using a capacitor
• CPC Class Codes: G01J 2001/4266 : for measuring solar light
• CPC Class Codes: G02B 19/0028 : refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0076 : for use with a detector G02B19/009, G02B19/0095 take precedence
• CPC Class Codes: G02B 5/021 : the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: G02B 5/0215 : the surface having a regular structure
• CPC Class Codes: G02B 5/0221 : the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0242 : by means of dispersed particles
• CPC Class Codes: G02B 5/0278 : used in transmission

Abstract

The inventive sensor device includes a support structure, a sensing element mounted on the support substrate for sensing optical radiation and generating an electrical output signal in response thereto, and an encapsulant encapsulating the sensing element on the support structure. The encapsulant being configured to define a lens portion for focusing incident optical radiation onto an active surface of the sensing element, and an optical radiation collector portion surrounding the lens portion for collecting and redirecting optical radiation that is not incident the lens portion onto the active surface of the sensing element. The collector portion may be a parabolic reflector that reflects incident light by total internal reflection. The sensor device may be incorporated into an assembly including a diffuser positioned across an aperture, and/or may be incorporated into a vehicle accessory such as a rearview mirror assembly.

Claims

1. A sensor assembly comprising:

a secondary optical element; and

a sensor device positioned to receive optical radiation passing through said secondary optical element, said sensor device comprising;

a support structure;

a sensing element mounted on said support structure for sensing optical radiation and generating an electrical signal in response thereto; and

an encapsulant encapsulating said sensing element on said support structure, said encapsulant being configured to define an optical radiation collector portion for collecting and redirecting incident optical radiation towards said sensing element.

2. The sensor assembly of claim 1, wherein said encapsulant being further configured to define a lens portion centrally located within said optical radiation collector portion for focusing incident optical radiation onto an active surface of said sensing element.

3. The sensor assembly of claim 2, wherein said lens portion is elliptical.

4. The sensor assembly of claim 3, wherein the major axis of said elliptical lens portion is aligned with the optical axis of the sensor device.

5. The sensor assembly of claim 4 and further comprising a housing having an aperture, wherein the optical axis of the sensor device is aligned with the center of said aperture.

6. The sensor assembly of claim 5, wherein said collector portion includes a parabolic surface.

7. The sensor assembly of claim 6, wherein said parabolic surface redirects incident optical radiation towards said sensing element by total internal reflection.

8. The sensor assembly of claim 7, wherein said collector portion includes an annular light receiving surface that lies in a plane perpendicular to the major axis of said elliptical lens portion and is disposed around said elliptical lens portion.

9. The sensor assembly of claim 1, wherein said support structure is a lead frame having at least first and second electrical leads electrically coupled to said sensing element.

10. The sensor assembly of claim 9, wherein said sensing element is mounted on one of said first and second electrical leads.

11. The sensor assembly of claim 10 and further including a wire bond extending from one of said first and second electrical leads to said sensing element.

12. The sensor assembly of claim 1, wherein the diffusing element is used to characterize the field of view.

13. The sensor assembly of claim 12, wherein said secondary optical element is further characterized so that the expanse of the field of view is greater in one direction than in another.

14. The sensor assembly of claim 1, wherein said support structure is a portion of a lead frame.

15. The sensor assembly of claim 14, wherein said portion of the lead frame includes at least two leads electrically coupled to said sensing element, and wherein said leads are retained by said encapsulant.

16. The sensor assembly of claim 1, wherein said collector portion includes a parabolic surface.

17. The sensor assembly of claim 16, wherein said parabolic surface redirects incident optical radiation towards said sensing element by total internal reflection.

18. The sensor assembly of claim 1, wherein said sensing element is sensitive to visible light.

19. The sensor assembly of claim 1, wherein said sensing element comprises:

a light transducer exposed to light, the light transducer operative to accumulate charge in proportion to light incident over an integration period; and

a sensor logic circuit in communication with the exposed light transducer, the sensor logic circuit operative to output a discrete light signal according to the accumulated exposed light transducer charge.

20. The sensor assembly of claim 19, wherein said integration period is variable in response to a received integration signal.

21. The sensor assembly of claim 19, wherein the integration period is of a length of time that is predetermined prior to accumulation of charge during the integration period.

22. The sensor assembly of claim 1, wherein said encapsulant is made of an epoxy.

23. A rearview mirror assembly for a vehicle, said rearview mirror assembly comprising:

a housing;

a mirror disposed in said housing;

a secondary optical element; and

a sensor device positioned in said housing to receive optical radiation passing through said secondary optical element, said sensor device comprising;

a support structure;

a sensing element mounted on said support structure for sensing optical radiation and generating an electrical signal in response thereto; and

an encapsulant encapsulating said sensing element on said support structure, said encapsulant being configured to define an optical radiation collector portion for collecting and redirecting incident optical radiation towards said sensing element.

24. The rearview mirror assembly of claim 23, wherein said optical radiation collector portion has a parabolic reflecting surface for collecting and reflecting incident optical radiation towards said sensing element.

25. The rearview mirror assembly of claim 23, wherein said optical radiation collector portion collects and redirects incident optical radiation towards said sensing element by total internal reflection.

26. The rearview mirror assembly of claim 23, wherein said mirror is an electro-optic mirror element.

27. The rearview mirror assembly of claim 26 and further comprising a processing circuit coupled to said sensor device for controlling said electro-optic mirror in response to light levels sensed by said sensing element.

28. The rearview mirror assembly of claim 27, wherein said sensor device is aimed forward of the vehicle for sensing ambient light levels.

29. The rearview mirror assembly of claim 27, wherein said sensor device is aimed rearward of the vehicle for sensing glare.

30. The rearview mirror assembly of claim 27 and further comprising a second sensor device for sensing light levels from sources in a different field of view from the first sensor device.

31. The rearview mirror assembly of claim 30, wherein said second sensor device comprises:

a second support structure;

a second sensing element mounted on the second support structure for sensing optical radiation and generating an electrical output in response thereto; and

a second encapsulant encapsulating said second sensing element on said second support structure, said second encapsulant being configured to define a second lens portion for focusing incident optical radiation onto an active surface of said second sensing element, and a second optical radiation collector portion surrounding the second lens portion for collecting and redirecting optical radiation that is not incident the second lens portion onto the active surface of said second sensing element.

32. The rearview mirror assembly of claim 27, wherein said processing circuit is further configured to generate light control signals to control at least one vehicle light in response to light levels sensed by said sensing element.

33. A vehicle accessory for mounting in a vehicle, said vehicle accessory comprising:

a secondary optical element; and

a sensor device positioned to receive optical radiation passing through said secondary optical element, said sensor device comprising;

a support structure;

a sensing element mounted on said support structure for sensing optical radiation and generating an electrical signal in response thereto; and

an encapsulant encapsulating said sensing element on said support structure, said encapsulant being configured to define an optical radiation collector portion for collecting and redirecting incident optical radiation towards said sensing element.

34. The vehicle accessory of claim 33, wherein said optical radiation collector portion has a parabolic reflecting surface for collecting and reflecting incident optical radiation towards said sensing element.

35. The vehicle accessory of claim 33, wherein said optical radiation collector portion collects and redirects incident optical radiation towards said sensing element by total internal reflection.

36. The vehicle accessory of claim 33 and further comprising a processing circuit coupled to said sensor device for generating light control signals to control at least one vehicle light in response to light levels sensed by said sensing element.

37. The vehicle accessory of claim 36, wherein said at least one vehicle light includes vehicle headlamps and said processing circuit controls the on/off state of the vehicle headlamps.

38. The vehicle accessory of claim 36, wherein said at least one vehicle light includes interior display lights.

39. The vehicle accessory of claim 33, wherein said sensor device is positioned to sense sun loading on the vehicle.