WHITE POINT ADJUSTMENT FOR MULTICOLOR KEYBOARD BACKLIGHT

• US 20100300856A1
• Filed: 06/01/2009
• Published: 12/02/2010
• Est. Priority Date: 06/01/2009
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Culter, Reese T., Kerr, Duncan, Pance, Aleksandar, Bilbrey, Brett, Slack, Brandon Dean
• Granted Patent: US 8,282,261 B2
• Time in Patent Office: Days
• US Class Current: 200/314
• CPC Class Codes: G02B 6/0001 specially adapted for lighting devices or systems lighting or signalling on vehicles using light guides B60Q1/00; lighting devices for vehicle dashboards B60Q3/10; lighting devices for vehicle interior using light guides B60Q3/62; lighting devices mounted on the vehicle rear part using light guides F21S43/235; measuring arrangements having light conducting pointers G01D13/265; illumination of liquid crystal displays G02F1/1336; illuminated signs G09F13/00
• CPC Class Codes: H01H 2219/038 ambient light dependent
• CPC Class Codes: H01H 2219/039 Selective or different modes of illumination
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]

Abstract

There are provided systems, devices and methods for operating a light source to match a white point of ambient light. In one embodiment, a light control system is provided. The light control system includes a light source and a light sensor. The light sensor is configured to operate in conjunction with the light source to provide a visual effect. A controller is electrically coupled to the light source and the light sensor and configured to determine the intensity and color of light to which the light sensor is exposed and dynamically adjust the output of the light source to match the determined intensity and color of light to which the light sensor is exposed.

Claims

1. A light control system comprising:

a multicolor light source;

a light sensor, configured to sense ambient light and operate in conjunction with the multicolor light source to provide a visual effect; and

a controller communicatively coupled to the multicolor light source and the light sensor, wherein the controller determines a white point of the sensed ambient light and dynamically adjusts an output of the multicolor light source based at least partially on the white point of the sensed ambient light.

2. The light control system of claim 1 further comprising a wave guide connected to each of the light source and multicolor light sensor.

3. The light control system of claim 2, wherein:

the light sensor receives ambient light through a passage defined in the wave guide; and

the multicolor light source emits the output through the passage.

4. The light control system of claim 1 wherein the multicolor light source comprises a red LED, a green LED and a blue LED.

5. The light control system of claim 1 wherein:

the controller references a calibration table to determine a white point output for the light source; and

the controller uses the white point output to dynamically adjust the output of the multicolor light source.

6. The light control system of claim 4 wherein:

the calibration table includes a plurality of entries; and

each of the plurality of entries comprises a red, green and blue value

7. The light control system of claim 5 wherein the controller actuates the red, green and blue LEDs according to the red, green and blue values retrieved from the calibration table.

8. The light control system of claim 4, wherein the employs the white point output to dynamically adjust a non-white output of the multicolor light source.

9. The light control system of claim 1 wherein the multicolor light source comprises a top-firing LED.

10. The light control system of claim 1 wherein the multicolor light source is a side firing LED.

11. The light control system of claim 1 wherein the multicolor light source is configured to back light a keyboard.

12. The light control system of claim 11 wherein the lights sensor is located under a keycap for a key of the keyboard.

13. The light control system of claim 1 wherein the light sensor comprises one or more narrowband photosensitive devices.

14. The light control system of claim 1 wherein the light sensor comprises a broadband photosensitive device.

15. A method of operating a back lighting system of a keyboard comprising:

actuating a light sensor to sense ambient light;

determining a white point of the ambient light; and

actuating a multicolor light source to dynamically to provide a desired white point output based on the determined white point of the ambient light.

16. The method of claim 15 comprising time division multiplexing actuation of the light sensor and the light source.

17. The method of claim 15, wherein the operation of actuating a multicolor light source comprises pulse width modulating an input to the multicolor light source.

18. The method of claim 15 wherein determining the white point of sensed light comprises determining an intensity of the sensed light at discrete wavelength ranges.

19. The method of claim 18 wherein the discrete wavelength ranges comprise a wavelength range that includes red light, a wavelength range that includes green light and a wavelength range the includes blue light.

20. A backlit keyboard comprising:

one or more light sources comprising independently operable red LEDs, green LEDs and blue LEDs;

one or more light distribution networks to distribute light to one or more keys of the keyboard, the keys comprising;

a transparent portion through which light emitted from the one or more light sources may pass; and

an opaque surface adjacent the transparent portion;

one or more light sensors configured to sense ambient light; and

a controller configured to determine intensity and color of the sensed ambient light and actuate the red, green and blue LEDs to create an output light having an illumination approximately equal to the ambient light reflected from the opaque surface.