Method and apparatus for constant light output pulsed L.E.D. illumination

• US 7,393,119 B2
• Filed: 02/12/2007
• Issued: 07/01/2008
• Est. Priority Date: 03/19/1998
• Status: Expired due to Fees

• Current Assignee: Lemaire Illumination Technologies LLC
• Original Assignee: Charles A. Lemaire
• Inventors: Lebens, Gary A., Bourn, Charles T., Lemaire, Charles A.
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US11/674,143
• Publication Number:
  US 20070133199A1
• Time in Patent Office: 505 Days
• Field of Search: 362/157, 362/184, 362/205, 362/800, 362/802, 315/127
• US Class Current: 362/205
• CPC Class Codes: F21L 4/027 the light sources being a LED
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H04B 10/502 LED transmitters
• CPC Class Codes: H04B 10/564 Power control
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/32 Pulse-control circuits
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y10S 362/80 Light emitting diode
• CPC Class Codes: Y10S 362/802 Position or condition responsive switch

Abstract

An illumination source includes a plurality of LEDs, and an electrical circuit that selectively applies power from the DC voltage source to the LED units, wherein the illumination source is suitable for handheld portable operation. In some embodiments, the electrical circuit further includes a control circuit for driving the LEDs with electrical pulses at a frequency high enough that light produced has an appearance to a human user of being continuous rather than pulsed, the control circuit changing a pulse characteristic to adjust a proportion of light output having the first characteristic color spectrum output to that having the second characteristic color spectrum output. Some embodiments provide an illumination source including a housing including one or more LEDs; and a control circuit that selectively applies power from a source of electric power to the LEDs, thus controlling a light output color spectrum of the LEDs.

Claims

1. A method of providing general-purpose illumination in a device of such compact size and low weight as to be suitable for single-handed portable operation by a user, comprising:

providing at least one LED in a housing configured to be held in a single hand, wherein each of the at least one LED emits light when driven by an electrical current;

connecting a battery to the housing;

electronically switching to alternately connect and disconnect an electrical path between the battery and the at least one LED at a high-enough frequency such that a human eye would not perceive the switching; and

controlling, across a battery-voltage range that would otherwise vary an average intensity of LED light output, the electronic switching to generate a substantially constant average light output intensity from the at least one LED.

2. The method of claim 1, wherein the connecting of the battery includes receiving the battery into the housing.

3. The method of claim 1, wherein the connecting of the battery includes mounting the battery onto the housing.

4. The method of claim 1, wherein the controlling of the electronic switching includes varying a pulse width such that the pulse width increases as battery voltage decreases.

5. The method of claim 1, wherein the controlling of the electronic switching includes varying a pulse frequency such that the pulse frequency increases as battery voltage decreases.

6. The method of claim 1, wherein the controlling of the electronic switching includes maintaining an average predetermined light output level of the LED units by sensing a battery voltage and adjusting a pulse width to the LED units based on the measured voltage to maintain the average light output at the predetermined level.

7. The method of claim 1, wherein the controlling of the electronic switching includes maintaining an average predetermined light output level of the LED units by sensing a battery voltage and adjusting a pulse frequency to the LED units based on the measured voltage to maintain the average light output at the predetermined level.

8. The method of claim 1, wherein the controlling of the electronic switching includes maintaining an average predetermined light output level of the LED units by sensing a light output and adjusting a pulse width to the LED units based on the measured voltage to maintain the average light output at the predetermined level.

9. The method of claim 1, wherein the controlling of the electronic switching includes maintaining an average predetermined light output level of the LED units by sensing a light output and adjusting a pulse energy to the LED units based on the measured voltage to maintain the average light output at the predetermined level.

10. The method of claim 1, wherein the controlling of the electronic switching includes maintaining an average predetermined light output level of the LED units by sensing a light output and adjusting a pulse frequency to the LED units based on the measured voltage to maintain the average light output at the predetermined level.

11. An LED illumination source apparatus, comprising:

a housing of such compact size and low weight as to be suitable for single-handed portable operation by a user, and configured to hold a battery;

at least one LED mounted to the housing; and

a control circuit having an electronic switch operatively coupled to alternately connect and disconnect electrical power from the battery to the control circuit, such that the control circuit selectively applies electrical power from the battery to the at least one LED, wherein the control circuit maintains a substantially constant average light output characteristic of the at least one LED as a voltage of the voltage source varies over a range that would otherwise vary the light output characteristic by adjusting a proportion of connect time to disconnect time.

12. The apparatus of claim 11, wherein the control circuit selectively applies electrical power from the battery to the at least one LED without a series resistor between the battery and the at least one LED.

13. The apparatus of claim 11, wherein the control circuit maintains the light output intensity of the LED units at a substantially constant average level by increasing a proportion of connect time of the connecting as the voltage of the DC voltage source decreases.

14. The apparatus of claim 11, wherein the control circuit maintains the light output intensity of the LED units as the voltage of the DC voltage source varies by increasing a connect time pulse width as the voltage of the DC voltage source decreases.

15. The apparatus of claim 11, wherein the control circuit maintains the light output intensity of the LED units as the voltage of the DC voltage source varies by increasing a connect time pulse frequency as the voltage of the DC voltage source decreases.

16. An apparatus for providing general-purpose illumination of such compact size and low weight as to be suitable for single-handed portable operation by a user, comprising:

a housing configured to be held in a single hand;

an LED that emits light when driven by an electrical current, wherein the LED is mounted to the housing;

means for mounting a battery to the housing;

means for electronically switching to alternately connect and disconnect an electrical path between the battery and the at least one LED at a high-enough frequency such that a human eye would not perceive the switching; and

means for controlling, across a battery-voltage range that would otherwise vary an average intensity of LED light output, the means for electronic switching to generate a substantially constant average light output intensity from the at least one LED.

17. The apparatus of claim 16, wherein the means for controlling maintains an average predetermined light output level of the LED units by sensing a voltage and adjusting a pulse frequency to maintain the average light output at the predetermined level.

18. The apparatus of claim 16, wherein the means for controlling maintains an average predetermined light output level of the LED units by sensing a voltage and adjusting a pulse frequency to maintain the average light output at the predetermined level.

19. The apparatus of claim 16, wherein the means for controlling maintains an average predetermined light output level of the LED units by sensing a light output and adjusting a pulse frequency to maintain the average light output at the predetermined level.

20. The apparatus of claim 16, wherein the means for controlling maintains an average predetermined light output level of the LED units by sensing a light output and adjusting a pulse frequency to maintain the average light output at the predetermined level.