Multichip led lighting device

• US 20060087843A1
• Filed: 12/22/2003
• Published: 04/27/2006
• Est. Priority Date: 01/27/2003
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Matsui, Nobuyuki, Tamura, Tetsushi, Tanimoto, Noriyasu, Setomoto, Tatsumi, Shimizu, Masanori
• Granted Patent: US 7,322,718 B2
• Time in Patent Office: Days
• US Class Current: 362/249.10
• CPC Class Codes: F21V 19/04 with provision for changing light source, e.g. turret auxiliary devices for cleaning, placing, or removing incandescent lamps H01K3/32, fluorescent lamps H01J9/006
• CPC Class Codes: F21V 23/006 the substrate being distinct from the light source holder
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/18 using temperature feedback
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• CPC Class Codes: H05B 45/395 Linear regulators
• CPC Class Codes: H05B 45/46 having LEDs disposed in parallel lines
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

In a module socket, a connecter and a connector are connected by wiring, and three LED modules are connected in parallel with respect to a constant voltage circuit unit via the wiring. Each module has a constant current circuit unit and an LED mounting unit. The constant current circuit unit includes one resistor and two transistors mounted on a surface of a sub-substrate on which a conductive land is formed. The sub-substrate is bonded to a main substrate.

Claims

1. A lighting device including:

an LED module composed of

a main substrate,

a light emitting diode bare chip provided on a main surface of the main substrate,

a power supply terminal for receiving power from a power supply source, and

a luminous intensity stabilization circuit provided between and electrically connected to the power supply terminal and the light emitting diode bare chip.

2. The lighting device of claim 1, wherein

the luminous intensity stabilization circuit is a constant current circuit.

3. The lighting device of claim 2, further including:

a constant voltage circuit that uses the power from the power supply source to supply a constant voltage to the power supply terminal,

wherein, in the LED module, power that has been supplied via the power supply terminal is then controlled by the constant current circuit so as to have a constant current, and the resulting constant current power is supplied to the light emitting diode chip.

4. The lighting device of claim 2, wherein

the LED module further includes a sub-substrate that is attached on the main substrate, and that has the constant current circuit formed thereon.

5. The lighting device of claim 4, wherein

the sub-substrate is made of one of resin, ceramic, and Si.

6. The lighting device of claim 1, wherein

the LED module is connected to a second LED module in parallel with respect to the power supply source, the second LED module being identical in structure to the LED module.

7. The lighting device of claim 1, further including:

a socket that is connected to the power supply source,

wherein the LED module is detachably loaded in the socket.

8. The lighting device of claim 7, wherein

the main substrate has a multi-layer structure composed of an insulative layer and a metal layer, the insulative layer being on a top main side of the main substrate, and the metal layer being on a bottom main side of the substrate,

and the socket includes a heatsink that, when the LED module is loaded in the socket and the socket thereby thermally contacts the metal layer of the main substrate, radiates heat generated by the light emitting diode bare chip during light emission from the LED module.

9. The lighting device of claim 1, wherein

the LED module further includes a thermal element provided in a vicinity of the light emitting diode bare chip and connected to the luminous intensity stabilization circuit, and

the luminous intensity stabilization circuit reduces current supply to the light emitting diode bare chip when the light emitting diode bare chip rises in temperature to a predetermined temperature or higher.

10. The lighting device of claim 3, wherein

the LED module further includes an abnormality detection unit that is provided in a vicinity of the light emitting diode bare chip and that detects an abnormality in the light emitting diode bare chip, and

the constant voltage circuit includes a control unit that reduces or stops provision of current to the LED module when the abnormality detection unit detects an abnormality in the light emitting diode bare chip.

11. The lighting device of claim 10, wherein

the abnormality detection unit is a thermal element that detects a temperature abnormality in the light emitting diode bare chip.

12. The lighting device of claim 3, wherein

the light emitting diode bare chip is one of a plurality included in the LED module that are divided into groups of light emitting diodes that are connected in series, the groups being connected in parallel with each other, and each group having a current detection unit connected thereto, and

the constant voltage circuit includes a control unit that reduces or stops supply of current to the LED module when one of the current detection units detects an abnormality in an amount of current in the light emitting diode bare chips.

13. The lighting device of claim 1, wherein

the LED module further includes a Zener diode connected to the luminous intensity stabilization circuit, in parallel with the light emitting diode bare chip.