Indoor light balancing

• US 8,132,938 B2
• Filed: 10/16/2007
• Issued: 03/13/2012
• Est. Priority Date: 10/17/2006
• Status: Active Grant

• Current Assignee: ChromoGenics AB
• Original Assignee: ChromoGenics AB
• Inventors: Granqvist, Claes Goran
• Primary Examiner(s): Payne, Sharon
• Application Number:
  US12/445,841
• Publication Number:
  US 20100296081A1
• Time in Patent Office: 1,610 Days
• Field of Search: 362/276, 362/552, 362/554, 362/559, 362/576, 362/147, 356/213, 349/16, 349/92, 349/187
• US Class Current: 362/276
• CPC Class Codes: F21S 11/00 Non-electric lighting devices or systems using daylight roofs with sky-light opening E04D13/03; sun blinds for windows with means for redirecting light onto ceiling of a room E06B9/00; hybrid lighting devices combining artificial and natural light F21S19/00; solar heat collectors F24S; solar cells or solar cell modules H01L31/00
• CPC Class Codes: F21V 23/0442 activated by means of a sensor, e.g. motion or photodetectors
• CPC Class Codes: F21V 23/0457 the sensor sensing the operating status of the lighting device, e.g. to detect failure of a light source or to provide feedback to the device
• CPC Class Codes: G02B 6/0008 the light being emitted at the end of the fibre

Abstract

An illumination system (1) is based on a window (21) having controllable transmittance and a light guide system (31) arranged for transferring light from a light guide input (33) to a light guide output (34). The light guide output is located in a same space (50) as the window (21), but at a distance therefrom (21). The illumination system includes elements for balancing (40) the transmittance of the window and a throughput of the light guide system. Preferably, the window is an outer window, the light guide input (33) is arranged for gathering day light and the light guide output (34) is arranged to illuminate an area (52) within sight from the window (21). Preferably the transmittance of the window (21) and/or the light throughput of the light guide system (31) are controlled. A method for illuminating a space (50) having a window (21) with controllable transmittance is presented.

Claims

1. Illumination system, comprising:

a window having controllable transmittance,

a light guide system arranged for transferring light from at least one light guide input to at least one light guide output;

said at least one light guide output being located in a same space as said window, but at a distance from said window,

wherein light passing through said light guide system does not pass through said window and light passing through said window does not pass through said light guide system, said light guide system being arranged for illuminating said same space by light passing said light guide system; and

balancing arrangement having a control unit arranged for balancing said transmittance of said window and a light throughput of said light guide system,

wherein said balancing changes an amount of light passing through said light guide system relative to an amount of light passing through said window.

2. Illumination system according to claim 1, wherein said window is an outer window of a room and said at least one light guide input is arranged for gathering day light.

3. Illumination system according to claim 1, wherein said at least one light guide output is arranged to illuminate an area within sight from said window.

4. Illumination system according to claim 1, wherein said control unit is arranged for controlling said transmittance of said window.

5. Illumination system according to claim 4, wherein said balancing arrangement comprises a chromogenic device.

6. Illumination system according to claim 5, wherein said balancing arrangement comprises an electrochromic device, a variable voltage supply and electrical connections between said variable voltage supply and said electrochromic device.

7. Illumination system according to claim 1, wherein said control unit is arranged for controlling said light throughput of said light guide system.

8. Illumination system according to claim 1, further comprising a light sensor connected to said control unit, and wherein said control unit is arranged to balance said transmittance of said window and a light throughput of said light guide system responsive to a signal from said light sensor.

9. Illumination system according to claim 8, comprising a plurality of light sensors connected to said control unit, and wherein said control unit is arranged to balance said transmittance of said window and a light throughput of said light guide system responsive to signals from said plurality of light sensors.

10. Illumination system according to claim 9, wherein said control unit is arranged to reduce a light intensity difference between said plurality of light sensors.

11. Illumination system according to claim 1, wherein said at least one light guide input is situated in a vicinity of said window.

12. Illumination system according to claim 1, wherein said light guide system comprises an optical fiber.

13. Method for illuminating a space having a window with controllable transmittance, comprising the steps of:

transferring light from at least one light guide input to at least one light guide output being located in said space at a distance from said window for illuminating said same space by said light transferred from said at least one light guide input to said at least one light guide output,

wherein light passing through said light guide output does not pass through said window and light passing through said window does not pass through said light guide output; and

balancing a transmittance of said window and a light throughput between said at least one light guide input and said at least one light guide output,

wherein an amount of light passing through said light guide output relative to an amount of light passing through said window is changed.

14. Method according to claim 13, comprising the further step of:

gathering day light into said at least one light guide input.

15. Method according to claim 13, wherein said step of balancing in turn comprises the step of controlling said transmittance of said window.

16. Method according to claim 13, wherein said step of balancing in turn comprises the step of controlling said light throughput of said light guide system.

17. Method according to claim 13, comprising the further step of:

measuring a light intensity, whereby said step of balancing is performed responsive to said measured light intensity.

18. Method according to claim 17, wherein light intensity is measured at a plurality of locations, whereby said step of balancing is performed responsive to said measured light intensity at said plurality of locations.

19. Method according to claim 13, wherein said step of balancing is performed to maintain a measured light intensity at a constant level as long as there is enough light available.

20. Method according to claim 13, wherein said step of balancing is performed to reduce a light intensity difference between different locations within said space.