Light emitting diode retrofit lamp

• US 5,463,280 A
• Filed: 03/03/1994
• Issued: 10/31/1995
• Est. Priority Date: 03/03/1994
• Status: Expired due to Term

• Current Assignee: ABL IP Holding LLC (Acuity Brands, Inc.)
• Original Assignee: National Service Industries, Inc. (Alsco Incorporated)
• Inventors: Johnson, James C.
• Primary Examiner(s): Pascal, Robert J.
• Assistant Examiner(s): SHINGLETON, MICHAEL B
• Application Number:
  US08/206,594
• Time in Patent Office: 607 Days
• Field of Search: 362/800, 362/249, 362/252, 362/227, 362/234, 315/250, 315/324, 315/185 R, 315/185 S, 315/192, 315/188, 315/187, 315/193, 315/307, 315/291, 315/209 R, 315/224, 315/294, 315/310, 379/396
• US Class Current: 315/187
• CPC Class Codes: F21K 9/232 specially adapted for generating an essentially omnidirectional light distribution, e.g. with a glass bulb
• CPC Class Codes: F21V 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2107/90 on two opposite sides of supports or substrates
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/357 specially adapted for retrofit LED light sources
• 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

Abstract

A retrofittable lamp using light emitting diodes as the illumination source, the lamp is fitted with any one of the common lamp bases and is intended as a retrofit for incandescent lamps having such bases in illuminated signs such as exit signs and the like. The invention contemplates the packaging of a number of light emitting diodes in a circuit usually having a current limiting device to allow LED operation at a desired current level. The light emitting diodes are placed within a standard glass or plastic bulb envelope in arrangements capable of providing even illumination from the lamp.

Claims

1. A lamp capable of operation on standard line voltages and particularly useful as a replacement lamp in an emergency exit sign and the like, comprising:

a plurality of light emitting diodes arranged in series and comprising a circuit locatable within the spatial confines of the lamp;

means disposed in the circuit for limiting current through the light emitting diodes, said means comprising a capacitor acting as the only effective limiting impedance in the circuit; and

,

a diode bridge disposed in the circuit between the light emitting diodes and the capacitor.

2. The lamp of claim 1 wherein the circuit further comprises a varistor disposed in the circuit between the capacitor and the diode bridge to suppress current surges.

3. The lamp of claim 1 wherein the number of light emitting diodes in the circuit is approximately twenty.

4. A lamp capable of operation on standard line voltages and particularly useful as a replacement lamp in an emergency exit sign and the like, which exit sign is provided with at least one socket intended to receive a base of an exit sign lamp which is replaced by the present lamp, the present lamp having a base which can be received into the socket, comprising:

a plurality of light emitting diodes arranged in series and comprising a circuit locatable within the spatial confines of the lamp;

means disposed in the circuit for limiting current through the light emitting diodes, said means comprising a capacitor acting as the only effective limiting impedance in the circuit; and

,

means for rectifying current disposed in the circuit between the light emitting diodes and the capacitor.

5. The lamp of claim 4 wherein the rectifying means comprise a diode bridge.

6. The lamp of claim 5 wherein the number of light emitting diodes in the circuit is approximately twenty.

7. A lamp capable of operation on standard line voltages and particularly useful as a replacement lamp in an emergency sign and the like, comprising:

a plurality of light emitting diodes arranged in series and comprising a circuit locatable within the spatial confines of the lamp;

a single circuit element arranged in the circuit for limiting current through the light emitting diodes, the single circuit element comprising the only effective limiting impedance in the circuit and comprising a capacitor; and

,

a diode bridge disposed within the circuit between the light emitting diodes and the single circuit element.

8. A lamp capable of operation on standard line voltages and particularly useful as a replacement lamp in an emergency sign and the like, comprising:

a plurality of light emitting diodes arranged in series and comprising a circuit locatable wtihin the spatial confines of the lamp;

a single circuit element arranged in the circuit for limiting current through the light emitting diodes, the single circuit element comprising the only effective limiting impedance in the circuit; and

,

a diode bridge disposed within the circuit between the light emitting diodes and the single circuit element, the single circuit element comprising a capacitor.