Photosensitive element assembly

Patent metadata

Field	Value
Publication number	US-10196855-B2
Application number	US-201414459825-A
Country	US
Kind code	B2
Filing date	Aug 14, 2014
Priority date	Aug 14, 2014
Publication date	Feb 5, 2019
Grant date	Feb 5, 2019

Abstract

A sensor assembly comprises a housing having a major face and a side edge. The side edge is formed of a material that is capable of conducting light. A photosensitive element is positioned within the housing and facing the major face of the housing. A reflector is positioned within the housing. The reflector is shaped to direct light entering through the side edge onto the photosensitive element.

First claim

What is claimed is:

1. A sensor assembly, comprising:
a housing having a major face and a side edge, wherein at least a portion of the major face and at least a portion of the side edge are formed of a material that is capable of conducting light;
a photosensitive element positioned within the housing, wherein the photosensitive element comprises a front face that faces the major face of the housing; and
a reflector positioned within the housing, the reflector shaped to direct light entering through the side edge onto the photosensitive element, and
wherein the reflector is further configured to block the front face of the photosensitive element from being exposed to light entering through the at least portion of the major face in a direction normal to a plane containing the front face of the photosensitive element.

2. The sensor assembly of claim 1 , wherein the reflector has a first surface oriented so that a surface normal of the first surface is from about 30 degrees to about 60 degrees from the direction normal to the plane containing the front face of the photosensitive element.

3. The sensor assembly of claim 2 , wherein the surface normal of the first surface is about 45 degrees from the direction normal to the plane containing the front face of the photosensitive element.

4. The sensor assembly of claim 2 , wherein the first surface has a curvature, such that a projection of the first surface in the plane containing the front face of the photosensitive element curves around the photosensitive element.

5. The sensor assembly of claim 2 , wherein the reflector has a second surface parallel to the major face to block the front face of the photosensitive element from being exposed to the light entering through the at least portion of the major face in the direction normal to the plane containing the front face of the photosensitive element.

6. The sensor assembly of claim 1 , wherein the reflector is configured so that the photosensitive element has a greater response to a unit of light entering the housing at an angle of about 45 degrees away from normal to the plane containing the front face of the photosensitive element than to a unit of light entering the housing normal to the plane.

7. The sensor assembly of claim 1 , wherein:
the housing has a back plate opposite the main face, the back plate configured to be mounted to a surface, and
the housing is rotatable with respect to the back plate, for permitting rotation of the sensor assembly after the back plate is mounted.

8. The sensor assembly of claim 2 , wherein
the major face of the housing has a circular shape and a first area,
the side edge of the housing has an area projection smaller than the first area.

9. The sensor assembly of claim 1 , wherein the reflector is arranged symmetrically with respect to the photosensitive element.

10. The sensor assembly of claim 1 , wherein:
the reflector has a first surface oriented from about 30 degrees to about 60 degrees from the direction normal to the plane containing the front face of the photosensitive element;
the first surface has a curvature, such that a projection of the first surface in the plane containing the front face of the photosensitive element curves around the photosensitive element;
the reflector has a second surface parallel to the major face to block the front face of the photosensitive element from being exposed to the light entering through the at least portion of the major face of the housing in the direction normal to the plane containing the front face of the photosensitive element; and
the housing has a back plate opposite the main face, the back plate configured to be mounted to a surface, and the housing is rotatable with respect to the back plate, for permitting rotation of the sensor assembly after the back plate is mounted.

11. A controller for use in a load control system for controlling an electrical load, the controller comprising:
a processor configured to:
combine a first sensor signal and a second sensor signal from at least a first sensor assembly and a second sensor assembly, respectively, the first and second sensor signals representing light levels at a window, the first and second sensor assemblies oriented so that the first sensor assembly has a maximum response to light entering a housing of the first sensor assembly at a first angle with respect to a normal of a plane of the window and the second sensor assembly has a maximum response to light entering a housing of the second sensor assembly at a second angle with respect to the normal of the plane of the window; and
transmit a command to automatically control the electrical load based on the combined first and second sensor signals,

wherein the housing of the first sensor assembly has a major face and a side edge, wherein at least a portion of the major face and at least a portion of the side edge are formed of a material that is capable of conducting light, and wherein the first sensor assembly further comprises:
a photosensitive element positioned within the housing of the first sensor assembly, wherein the photosensitive element comprises a front face that faces the major face; and
a reflector positioned within the housing of the first sensor assembly, the reflector shaped to direct light entering through the side edge onto the photosensitive element, and
wherein the reflector is further configured to block the front face of the photosensitive element from being exposed to light entering through the at least portion of the major face in a direction normal to a plane containing the front face of the photosensitive element.

12. The controller of claim 11 , wherein the processor is configured to combine the first sensor signal and the second sensor signal by summing the first sensor signal and the second sensor signal.

13. The controller of claim 12 , wherein the processor is further configured to:
identify a sensor failure when at least one of the first sensor assembly or the second sensor assembly is not operational; and
enter an operating mode for controlling the electrical load without using the first sensor signal and without using the second sensor signal, when the sensor failure is identified.

14. The controller of claim 11 , wherein the processor is configured to combine the first sensor signal and the second sensor signal by receiving the first sensor signal and the second sensor signal asynchronously, and summing a most recently received first sensor signal with a most recently received second sensor signal.

15. The controller of claim 14 , wherein the processor is configured to sum the first sensor signal and the second sensor signal each time the processor receives either one of the first or the second sensor signals.

16. The controller of claim 11 , wherein the first and second angles are different from each other.

17. The controller of claim 11 , wherein the first and second angles are symmetric about the normal of the plane of the window.

18. The controller of claim 11 , wherein the first and second sensor assemblies are oriented so that an outward facing normal to a plane of a front surface of a photosensitive element of the second sensor assembly is in an opposite direction from an outward facing normal to the plane of the front surface of the photosensitive element of the first sensor assembly.

19. The controller of claim 11 , wherein the processor is further configured to transmit a command to automatically adjust a position of a motorized window treatment based on the combined first and second sen

Assignees

• Lutron Electronics Co

Inventors

• Blair Edward J
• Lundy Stephen
• Szoke Brandon L
• Kirby David A

Classifications

• E06B2009/6827

  sensing light · CPC title

• E06B9/68 Primary

  Operating devices or mechanisms, e.g. with electric drive · CPC title

• E06B9/72

  comprising an electric motor positioned inside the roller · CPC title

• Y02B20/40

  Control techniques providing energy savings, e.g. smart controller or presence detection · CPC title

• H05B47/11

  by determining the brightness or colour temperature of ambient light · CPC title