Illumination control system

• US 6,963,175 B2
• Filed: 08/28/2002
• Issued: 11/08/2005
• Est. Priority Date: 08/30/2001
• Status: Expired due to Term

• Current Assignee: Radiant Research Drive, Radiant Research Limited
• Original Assignee: Radiant Research Limited
• Inventors: Archenhold, Geoffrey Howard Gillett, Anderson, Keith
• Primary Examiner(s): TRAN, THUY V
• Application Number:
  US10/229,721
• Publication Number:
  US 20030057888A1
• Time in Patent Office: 1,168 Days
• Field of Search: 315/246, 315/291, 315/299, 315307-308, 362/227, 362230-231, 362/276, 362/800
• US Class Current: 315/291
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/24 using electrical feedback from LEDs or from LED modules
• CPC Class Codes: H05B 45/28 using temperature feedback
• CPC Class Codes: H05B 45/32 Pulse-control circuits
• CPC Class Codes: H05B 45/33 Pulse-amplitude modulation [PAM]
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A light emitting diode illumination control system is disclosed for driving a current circuit for energizing one or more LED light sources. The system comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and may employ a monitor for monitoring at least one ambient condition and a microprocessor operable to control the current circuit in response to the monitored condition.

Claims

1. A light emitting diode illumination system arranged to drive one or more light emitting diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and a current feedback means for monitoring current driving the light source(s).

2. An illumination system according to claim 1, wherein said system is arranged to control one or more light emitting diode sources which are configured to emit light within different wavelength bands.

3. An illumination control system according to claim 2, wherein said light sources are, configured to emit substantially monochromatic light centered on at least three different wavelengths.

4. An illumination system according to claim 1, wherein the system further comprises means for modifying and controlling the pulse amplitude modulation signal timing period and duty cycle.

5. An illumination system according to claim 4, wherein the means for modifying and controlling the pulse amplitude modulation signal timing period and duty cycle comprises a micro-processor, discrete electrical component circuit, fixed or programmable crystal oscillator or integrated circuit timer.

6. An illumination system according to claim 1, wherein the pulse amplitude modulated voltage control current circuit comprises means for providing a voltage for modulating pulse amplitude.

7. An illumination system according to claim 1, wherein the current feedback monitor comprises a discrete electrical circuit or current sensing integrated circuit.

8. An illumination system according to any preceding claim, wherein said system further comprises a monitor for monitoring at least one environmental condition and said microprocessor is adapted to control said pulse amplitude modulated voltage controlled current circuit in response to the monitored condition.

9. The illumination system according to claim 8 wherein said monitor is selected from the group comprising radiant, mechanical, thermal, electical, magnetic and chemical monitors.

10. The illumination system according to claim 8 wherein said monitor is selected from the group comprising temperature sensors, displacement detectors, angular sensors, velocity sensors, strain sensors, acceleration sensors, photo-emissive sensors, photo-conductive sensors, photo-voltaic sensors, pressure sensors, flow transducers, radiation sensors, chemical sensors and gas detectors.

11. An illumination system according to claim 1, wherein said system further comprises a communications module providing a data connection interface to an internal or external controlling device.

12. The illumination system according to claim 1, wherein the system further comprises means for receiving an external signal and for controlling the frequency and duty cycle of the pulse amplitude modulation control signal in synchronism with the external signal.

13. The illumination system according to claim 1, the control system being constituted as a closed-loop, solid state, illumination control system.

14. A light emitting diode illumination system arranged to drive one or more light emitting diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and a current feedback means for monitoring current driving the light source(s), wherein the pulse amplitude modulated voltage control current circuit comprises means for providing a voltage for modulating pulse amplitude, and wherein said means for providing a voltage comprises a programmable digital potentiometer that is provided as voltage provider.

15. A light emitting diode illumination system arranged to drive one or more light emitting diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and a current feedback means for monitoring current driving the light source(s), wherein the system further comprises means for receiving an external signal and for controlling the frequency and duty cycle of the pulse amplitude modulation control signal synchronism with the external signal, and wherein a solid state camera system is arranged to pass the external signal.

16. A light emitting diode illumination system arranged to drive one or more light diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and means for modifying and controlling the pulse amplitude modulation signal timing period and duty cycle.

17. A light emitting diode illumination system arranged to drive one or more light emitting diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, wherein the pulse amplitude modulated voltage control current circuit comprises means for providing a voltage for modulating pulse amplitude, and a programmable digital potentiometer is provided as voltage divider.

18. A light emitting diode illumination system arranged to drive one or more light emitting diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and the pulse amplitude modulated voltage control current circuit comprises a communications module providing a data connection interface to an internal or external controlling device.

19. A light emitting illumination system arranged to drive one or more light emitting diode sources which comprises a control system including a microprocessor arranged to control a pulse amplitude modulated (PAM) voltage controlled current circuit, and said system further comprises means for receiving an external signal and for controlling the frequency and duty cycle of the pulse amplitude modulation control signal in synchronism with the external signal.

20. A light emitting diode illumination system arranged to drive one or more light emitting diode light sources which comprises a control system including a microprocessor arranged to control a pulse amplitude (PAM) voltage controlled current circuit, the control system being constituted as a closed-loop illumination control system.