Process and apparatus for improving LED performance

• US 20050082989A1
• Filed: 09/22/2004
• Published: 04/21/2005
• Est. Priority Date: 09/22/2003
• Status: Abandoned Application

• Current Assignee: BTU Services, Inc.
• Original Assignee: BTU Services, Inc.
• Inventors: Marcum, Barbara L., Jones, Dale G., Youda, Yao
• Application Number:
  US10/947,775
• Publication Number:
  US 20050082989A1
• Time in Patent Office: Days
• US Class Current: 315/194
• CPC Class Codes: F21L 4/00 Electric lighting devices with self-contained electric batteries or cells
• CPC Class Codes: F21L 4/027 the light sources being a LED
• CPC Class Codes: F21L 4/08 characterised by means for in situ recharging of the batteries or cells
• CPC Class Codes: F21S 9/03 rechargeable by exposure to light
• CPC Class Codes: F21V 23/0442 activated by means of a sensor, e.g. motion or photodetectors
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/37 Converter circuits
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/20 Responsive to malfunctions or to light source life; for protection
• CPC Class Codes: Y02B 10/10 Photovoltaic [PV]
• 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: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

Process and apparatus for improving LED performance are disclosed in which, in one exemplary embodiment, a lamp having one or more LEDs is powered by at least one rechargeable battery that may be recharged by solar photovoltaic panel or any number of DC or AC power sources, including a car battery or household AC outlets. The power to illuminate the LEDs from the rechargeable battery is regulated by a control circuit that enables the LEDs to illuminate for at least twice the operating time for the same LEDs and the same rechargeable battery without the control circuit.

Claims

1. A method for regulating current supplied to one or more light-emitting diodes (LEDs) comprising the steps of connecting a control circuit comprising a control transistor to a fixed-capacity power supply, wherein the control circuit enables the one or more LEDs to operate for at least twice as long as the same one or more LEDs operating from the same fixed capacity power supply without the control circuit.

2. The method as recited in claim 1, wherein the one or more LEDs comprises at least two LEDs, and wherein the at least two LEDs are connected in parallel.

3. The method as recited in claim 1, wherein the fixed-capacity power supply is selected from the group consisting of nickel-cadmium (NiCd) batteries, nickel-metal hydride (NiMH) batteries, lead-acid batteries, sealed gel-cell lead acid batteries, lithium-ion (Li-Ion) batteries, proton exchange membrane (PEM) fuel cells, direct methanol fuel cells (DMFC), and combinations thereof.

4. The method as recited in claim 1, wherein the control transistor used in said control circuit is selected to provide twice the LED operating time compared with the operating time for the same one or more LEDs operating from the same fixed-capacity power supply without the control circuit.

5. The method as recited in claim 3, further comprising the step of recharging the fixed-capacity power supply with electrical energy which is obtained from a solar photovoltaic panel, from an external source of AC power, from an external source of DC power, by adding gaseous hydrogen, or by adding hydrogen-containing compounds in a non-gaseous form.

6. The method as recited in claim 1, further comprising the step of protecting said one or more LEDs from being burned out whenever DC voltage supplied to the control circuit exceeds a maximum forward voltage rating for the one or more LEDs by at least about 20%.

7. The method as recited in claim 1, wherein a photocell sensor is used in combination with a bias resistor and a switching transistor to adjust a base voltage of the control transistor in the control circuit to turn off the one or more LEDs in the daytime and turn on the one or more LEDs during low ambient lighting conditions.

8. A method for regulating current supplied to one or more light emitting diodes (LEDs) comprising the steps:

connecting a control circuit to a fixed-capacity power supply;

connecting one or more LEDs to the control circuit;

the control circuit adapted to extend a duration of LED light output time obtained from the fixed capacity power supply to be at least twice as long as the LED light output time from the same fixed capacity power supply without the control circuit.

9. The method as recited in claim 8, wherein the control transistor is a Darlington proprietary type control transistor.

10. The method as recited in claim 8, wherein the fixed capacity power supply is a battery which may be recharged using a solar photovoltaic panel, an external source of direct current electrical energy, or direct current electrical energy which is derived from an external source of alternating current electrical energy.

11. The method as recited in claim 8, wherein the fixed capacity power supply is a rechargeable battery.

12. The method as recited in claim 8, wherein a photocell sensor is used in combination with a bias resistor to adjust an output from a switching transistor to control the voltage supplied to a base of the control transistor, wherein the one or more LEDs are automatically turned off in the daytime and automatically turned on at night or in dim ambient lighting conditions.

13. The method as recited in claim 8, wherein the control transistor is selected to optimize performance of a specific number, type, and configuration of the one or more LEDs to provide useful LED output light while protecting said one or more LEDs from being burned out, even if the DC voltage supplied to said control circuit exceeds a maximum forward voltage of the one or more LEDs by at least about 20%.

14. The method as recited in claim 8, wherein the control transistor is selected for optimum performance measured by the duration of useful LED output light obtained from a specific number and type of parallel-connected LEDs.

15. The method as recited in claim 11, wherein the rechargeable battery is selected from a group consisting of nickel-metal hydride battery, lithium-ion battery, or sealed lead-acid gel cell battery.

16. The method as recited in claim 15, wherein the rechargeable battery can be recharged using a solar photovoltaic panel, an external charger adapter deriving DC power from an AC power source, a DC power source, or any combination thereof.

17. An apparatus for providing useful output light from light emitting diodes (LEDs) and for delivering power to external devices comprising a housing containing one or more LEDs, a DC power connection means;

and a control circuit connecting at least one fixed-capacity power source to the one or more LEDs;

wherein the apparatus further includes an accessory DC converter comprising DC power connection means to obtain regulated DC voltage for at least one of charging and operating external electronic devices.

18. The apparatus of claim 17, wherein the external electronic devices include cellular telephone chargers, cellular telephones, audio devices, electronic games, and personal desktop assistants.

19. The apparatus of claim 18, wherein the audio devices include walkman players, portable CD players, and MP3 players.

20. The apparatus of claim 18, wherein the electronic games include Nintendo Game Boys, and the personal desktop assistants include Palm Pilots and GPS locating devices.

21. A lighting assembly comprising a lamp and a photovoltaic panel, wherein the lamp comprises one or more LEDs, at least one rechargeable battery, and a printed circuit board (PCB) comprising a control transistor in electrical communication with both the one or more LEDs and the at least one rechargeable battery;

wherein the photovoltaic panel comprises a cable adapted for connecting with the lamp to enable charging the at least one rechargeable battery.

22. The light assembly of claim 21, wherein the photovoltaic panel comprises a set of tracks for slidably receiving the lamp.

23. The light assembly of claim 21, wherein the lamp comprises a lamp base and a lamp head, wherein the at least one chargeable battery is positioned in the lamp base and the one or more LEDs are positioned in the lamp head.

24. The light assembly of claim 21, wherein the lamp further comprises a photocell sensor in electrical communication with the PCB, the photocell being adapted to turn off the one or more LEDs during daytime.

25. A lighting assembly comprising a lamp including a lamp housing;

the lamp housing comprising at least one rechargeable battery suitable for supply of direct current;

one or more light emitting diodes (LEDs); and

a printed circuit board (PCB) comprising electrical components comprising at least one control transistor;

the PCB being adapted for controlling the supply of current from the at least one rechargeable battery to the one or more LEDs over a period of time;

said period of time being at least twice as long as the period of time the at least one rechargeable battery is capable of delivering direct current to the one or more LEDs in the absence of the PCB.

26. A lighting assembly comprising a lamp including lamp housing;

a reflector housing having a reflective receiving space positioned within the lamp housing;

one or more light emitting diodes (LEDs) positioned in the reflective receiving space of the reflector housing and electrically connected to a printed circuit board (PCB) comprising electrical components including a control transistor;

a fixed-capacity power supply capable of providing direct current positioned in the lamp housing and connected to the PCB via a plurality of electrical wires; and

wherein the PCB regulates the supply of direct current flowing from the fixed-capacity power supply to the one or more LEDs.

27. A method for operating one or more LEDs using a control transistor which regulates the current consumed by the LEDs, wherein the current consumed is approximately linear with the DC supply voltage, and wherein the control transistor protect the one or more LEDs from being burned out if the DC supply voltage supplied to the control transistor exceeds maximum rated value by at least about 20%.

28. The method as recited in claim 27, wherein 8 pieces of white 5 mm LEDs are enabled to operate to produce useful output light for a continuous period of at least about 24 hours, wherein the power supply consists of a fully-charged battery rated 3.6 VDC at 3000 mAh.

29. The method as recited in claim 27, wherein 3 pieces of white 5 mm LEDs are enabled to operate to produce useful output light for a continuous period of at least about 10 hours, wherein the power supply consists of a fully-charged battery rated 3.6 VDC at 750 mAh.