Optical Sampling and Control Element

• US 20090001253A1
• Filed: 06/10/2008
• Published: 01/01/2009
• Est. Priority Date: 06/26/2007
• Status: Active Grant

• Current Assignee: Polaris PowerLED Technologies, LLC (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Inventors: PEKER, Arkadiy, KORCHARZ, Dror, JACUBOVSKI, Migel, FERENTZ, Alon, BLAUT, Roni
• Granted Patent: US 7,812,297 B2
• Time in Patent Office: Days
• US Class Current: 250/205
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0285 using tables for spatial correction of display data
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

An optical sampling and control element for use with a luminaire exhibiting a cycle and a frame, the optical sampling and control element being constituted of a color sensor in optical communication with the luminaire; and a sampler connected to the outputs of the color sensor, the sampler comprising an integrator arranged to integrate the outputs of the color sensor over a predetermined period less than the frame.

Claims

1. An optical sampling and control element for use with a luminaire exhibiting a cycle and a frame, the optical sampling and control element comprising:

a color sensor in optical communication with the luminaire; and

a sampler connected to the outputs of said color sensor, said sampler comprising an integrator arranged to integrate said outputs of said color sensor over a predetermined period less than the frame.

2. An optical sampling and control element according to claim 1, wherein said sampler further comprises an analog to digital converter receiving the output of said integrator.

3. An optical sampling and control element according to claim 1, wherein said predetermined period is a single cycle of the luminaire sensed by said color sensor.

4. An optical sampling and control element according to claim 1, wherein said sampler further comprises an analog to digital converter in communication with said color sensor, said integrator receiving the output of said analog to digital converter.

5. An optical sampling and control element according to claim 4, further comprising a synchronizer, said analog to digital converter arranged to be responsive to said synchronizer to sample an adjacent cycle at an offset from a previous cycle.

6. An optical sampling and control element according to claim 5, wherein said integrator is configured to sum the converted outputs of said analog to digital converter over said predetermined period and normalize said sum.

7. An optical sampling and control element according to claim 1, further comprising a color manager arranged to receive the output of said sampler.

8. An optical sampling and control element according to claim 7, wherein said color manager comprises a pulse width modulation signal generator.

9. An optical sampling and control element according to claim 7, further comprising a light emitting diode driver arranged to receive the output of said color manager.

10. An optical sampling and control element according to claim 6, further comprising a color manager arranged to receive the output of said sampler, and wherein said color manager comprises:

a means for receiving a luminance setting input signal defining a luminance, on an individual frame basis, of the luminaire;

a means for receiving a color reference value;

a feedback controller requiring a plurality of frames to converge;

a modulated signal generator immediately responsive to said received luminance setting input signal and said feedback controller;

a scaler arranged to scale a first one of said received reference value and said output signal of said sampler, to be consonant with a second one of said received reference value and said output signal of said sampler; and

a difference circuit, arranged to output a signal representative of the difference between the output of said scaler and the output of said second one of said received reference value and said output signal of said sampler,

said feedback controller responsive to said output signal of said difference circuit to reduce said difference.

11. A method of optical sampling and control for use with a luminaire exhibiting a cycle and a frame, the method comprising:

receiving a tristimulus output representative of the luminaire; and

integrating said received tristimulus output over a predetermined period comprising at least one cycle and less than one frame.

12. A method according to claim 11, further comprising converting said integrated output to a digital value.

13. A method according to claim 12, wherein said predetermined period is a single cycle of said luminaire.

14. A method according to claim 11, further comprising:

periodically sampling said received tristimulus output; and

digitizing each of said periodic samples to a digital representation.

15. A method according to claim 14, wherein said predetermined period comprises a plurality of repetitive cycles of the luminaire, and wherein said periodic sampling of adjacent cycles is at an offset.

16. A method according to claim 15, further comprising:

summing said digitized periodic samples; and

normalizing said sum.

17. A method according to claim 11, further comprising controlling a color loop responsive to said integrated tristimulus output.

18. A method according to claim 17, further comprising generating a pulse width modulation signal responsive to said controlled color loop.

19. A method according to claim 18, further comprising driving said luminaire responsive to said generated pulse width modulation signal.

20. A method according to claim 11, further comprising:

receiving a luminance setting input signal defining the luminance of the luminaire on an individual frame basis;

receiving a color reference value;

scaling a first one of said received reference value and said integrated tristimulus output, to be consonant with a second one of said received reference value and said integrated tristimulus output; and

calculating a difference between said first one of said received reference value and said integrated tristimulus output, and said second one of said received reference value and said integrated tristimulus output.

21. An integrated optical sampling, control and generator element, comprising:

a color sensor;

a sampler responsive to the output of said color sensor; and

a color manager responsive to said sampler and to a received color reference value,

said color manager comprising a pulse width modulated signal generator arranged to output a plurality of pulse width modulated signals configured to illuminate a plurality of light emitting diode strings,

said color sensor arranged to be responsive to said illumination of said plurality of light emitting diode strings.

22. An integrated optical sampling, control and generator element according to claim 21, further comprising a light emitting diode string driver responsive to said output of said color manager and arranged to drive said plurality of light emitting diode strings.

23. An integrated optical sampling, control and generator element according to claim 21 or claim 22, wherein said sampler comprises an integrator arrange to integrate said output of said color sensor over one or more cycles of said pulse width modulated signal generator.