LED reading light

• US 6,161,910 A
• Filed: 12/14/1999
• Issued: 12/19/2000
• Est. Priority Date: 12/14/1999
• Status: Expired due to Term

• Current Assignee: Aerospace Lighting Corp (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Aerospace Lighting Corp (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Gloisten, Jennifer L., Pawelko, Tolek, Reisenauer, William E.
• Primary Examiner(s): Philogene, Haissa
• Application Number:
  US09/460,877
• Time in Patent Office: 371 Days
• Field of Search: 315/309, 315/312, 315/158, 315/224, 315/112, 362/800, 362/235, 362/227, 362/240, 362/294, 362/373
• US Class Current: 315/309
• CPC Class Codes: B60Q 3/12 lighting onto the surface to be illuminated
• CPC Class Codes: B60Q 3/44 Spotlighting, e.g. reading lamps
• 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: 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

An LED reading light assembly has an optical assembly, a power circuit board, a housing, and a control system. The optical assembly includes a holographic lens and an LED assembly comprising an LED circuit board and a plurality of LED'"'"'s disposed on the outward facing side of the LED circuit board. The power circuit board provides a constant source of electric current to power the LED'"'"'s. The housing includes a housing plate disposed behind the LED circuit board and a black anodized fin plate. The control system includes a temperature protection circuit monitoring the ambient temperature at the LED assembly during operation and adjusting the power supplied to the LED'"'"'s to maintain the ambient temperature within a selected temperature range.

Claims

1. An LED reading light assembly comprising:

(a) An optical assembly comprising;

(i) a holographic lens;

(ii) an LED assembly comprising an LED circuit board having an outward facing side and a plurality of LED'"'"'s disposed on the outward facing side, said LED assembly having an ambient temperature during operation

(b) a power circuit board adapted to supply a constant source of electric current to power the LED'"'"'s;

(c) a housing comprising

(i) a housing plate disposed behind the LED circuit board;

(ii) a black anodized fin plate; and

(d) a control system comprising a temperature protection circuit monitoring the ambient temperature at the LED assembly and adjusting the power supplied to the LED'"'"'s to maintain the ambient temperature within a selected temperature range.

2. An LED reading light assembly according to claim 1 further comprising an optical cavity formed by a cylinder mounted to the LED assembly.

3. An LED reading light assembly according to claim 1 wherein the temperature protection circuit reduces the power to the LED'"'"'s when the ambient temperature rises above a selected value.

4. An LED reading light assembly according to claim 1 wherein a reflective white solder mask coating is applied to the outward facing side of the LED circuit board.

5. An LED reading light assembly according to claim 1 wherein the temperature protection circuit comprises a temperature sensing device and a plurality of chains of a plurality of LED'"'"'s, each of said chains providing a constant source of electric current.

6. An LED reading light assembly according to claim 1 wherein the temperature protection circuit comprises a temperature sensing device and six chains of six LED'"'"'s, each of said chains providing a constant current source.

7. An LED reading light assembly according to claim 1 comprising:

(a) a back heat sink comprising a black anodized fin plate having a circular recess on one side and a radially finned surface on the other side, said fin plate having a plurality of wire receiving apertures extending therethrough;

(b) a soft, circular thermal pad received within the recess of the fin plate, said pad having a plurality of wire-receiving apertures extending through said pad and aligned with the wire-receiving apertures of said fin plate;

(c) a power printed circuit board having a plurality of wires extending from one side of said board and received by the wire-receiving apertures of said thermal pad and said fin plate;

(d) a front circular heat sink mounted to said power printed circuit board, said front heat sink having a plurality of wire-receiving apertures along its circumference;

(e) a front thermal pad mounted to the front heat sink;

(f) an LED circuit board having a plurality of wire'"'"'s extending from one side of said LED circuit board and received by the wire-receiving apertures of said front heat sink;

(g) a plurality of LED'"'"'s disposed on the other side of said LED circuit board;

(h) a plurality of fasteners for mounting said back heat sink, said back thermal pad and said power printed circuit board to one side of said front heat sink and for mounting said LED circuit board and front thermal pad to the other side of said front heat sink;

(i) a cylinder mounted to the front heat sink and surrounding the plurality of LED'"'"'s;

(j) a ball movably disposed on the cylinder for directing the light emitted by the LED'"'"'s;

(k) a flange mounted to the ball;

(l) a holographic lens mounted within the cylinder; and

(m) a retaining ring mounting the holographic lens within the cylinder.

8. An LED reading light assembly according to claim 1 wherein fifty LED'"'"'s are disposed on the LED circuit board.

9. An LED reading light assembly according to claim 1 wherein the housing is constructed of aluminum.

10. An LED reading light assembly according to claim 1, wherein the LED'"'"'s during operation emit light having a color rendering index of 85 and a color temperature of 5100 degrees Kelvin.

11. An LED reading light assembly according to claim 1 wherein the assembly is electrically connected to a 28 VDC electrical system.