Illumination unit with a solid-state light generating source, a flexible substrate, and a flexible and optically transparent encapsulant

• US 20040223328A1
• Filed: 01/20/2004
• Published: 11/11/2004
• Est. Priority Date: 05/09/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Chua, Jan tB Yin, Kuan, Yew Cheong, Lee, Kian Shin, Ou, Wen Ya
• Granted Patent: US 7,128,442 B2
• Time in Patent Office: Days
• US Class Current: 362/249
• CPC Class Codes: A61N 2005/0651 Diodes
• CPC Class Codes: A61N 5/0618 Psychological treatment
• CPC Class Codes: B60Q 1/2607 comprising at least two indicating lamps
• CPC Class Codes: B60Q 1/2696 Mounting of devices using LEDs
• CPC Class Codes: F21S 4/22 flexible or deformable, e.g. into a curved shape
• CPC Class Codes: F21S 4/24 of ribbon or tape form, e.g. LED tapes
• CPC Class Codes: F21S 43/14 Light emitting diodes [LED]
• CPC Class Codes: F21S 43/15 Strips of light sources
• CPC Class Codes: F21S 45/47 Passive cooling, e.g. using fins, thermal conductive elements or openings
• CPC Class Codes: F21V 29/70 characterised by passive heat-dissipating elements, e.g. heat-sinks
• CPC Class Codes: F21V 29/74 with fins or blades
• CPC Class Codes: F21V 29/89 Metals
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21Y 2103/10 comprising a linear array of point-like light-generating elements
• CPC Class Codes: F21Y 2107/70 on flexible or deformable supports or substrates, e.g. for changing the light source into a desired form
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: F21Y 2115/15 Organic light-emitting diodes [OLED]
• CPC Class Codes: F21Y 2115/30 Semiconductor lasers
• CPC Class Codes: H05K 1/0209 External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings
• CPC Class Codes: H05K 1/189 : characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/09781 : Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 2201/10106 : Light emitting diode [LED]
• CPC Class Codes: H05K 3/284 : for encapsulating mounted components H05K1/185 takes precedence

Abstract

An illumination unit includes a thin and flexible substrate and flexible electrical tracks formed on the flexible substrate. A number of solid-state light generating sources are arranged on the flexible substrate along the electrical tracks and are electrically connected to the electrical tracks. A flexible and optically transparent encapsulant is provided to encapsulate the light generating sources on the substrate such that the illumination unit is both thin and flexible.

Claims

1. An illumination unit, comprising:

a thin and flexible substrate;

a plurality of flexible electrical tracks formed on the flexible substrate;

a plurality of solid-state light generating sources arranged on the flexible substrate along the electrical tracks and being electrically connected to the electrical tracks;

a flexible and optically transparent encapsulant to encapsulate the light generating sources on the substrate such that the illumination unit is both thin and flexible.

2. The illumination unit of claim 1, wherein the encapsulant is made of biocompatible silicone.

3. The illumination unit of claim 1, wherein encapsulant is clear in color or tinted with dye.

4. The illumination unit of claim 1, wherein the encapsulant is of low thermal conductivity such that minimized heat is dissipated to the outer surface of the encapsulant.

5. The illumination unit of claim 1, wherein the light generating sources emit a broad-spectrum light.

6. The illumination unit of claim 1, wherein the light generating sources are selected from a group comprising light emitting diodes, laser diodes, and organic light emitting diodes.

7. The illumination unit of claim 6, wherein each of the diodes is a diode package selected from a group comprising a PCB (Printed Circuit Board) based diode package, a ceramic-based diode package, a leadframe-based diode package, a model-based diode package, a metal-based diode package.

8. The illumination unit of claim 7, wherein the diode package includes a reflector cup to reflect light and an optically designed dome shape to channel out the light at a predetermined viewing angle.

9. The illumination unit of claim 7, wherein the diode package includes a built-in heat sink to help dissipate heat generated by a diode within the diode package.

10. The illumination unit of claim 7, wherein the diode package further comprises a Light Emitting Diode chip that is covered with luminescent material.

11. The illumination unit of claim 1, wherein the flexible substrate is made of polyimide material.

12. The illumination unit of claim 1, wherein the flexible substrate is made of any electrically non-conductive but thermally conductive material.

13. The illumination unit of claim 1, further comprising a plurality of electronic components arranged on the flexible substrate.

14. The illumination unit of claim 13, wherein the electronic components are selected from a group comprising resistors, capacitors, transistors, current regulators, and drivers for light emitting diodes.

15. The illumination unit of claim 1, further comprising at least a heat sink track arranged on the substrate, and an anode track and a cathode track and the heat sink track is formed between the anode and cathode tracks.

16. The illumination unit of claim 15, further comprising a heat-conducting frame surrounding the substrate, the heat sink track being thermally connected to the frame.

17. The illumination unit of claim 16, further comprising a heat-conducting sheet attached with the substrate via a thermally conductive adhesive paste and in contact with the heat-conducting frame, wherein the heat-conducting sheet is made of one of metal or ceramic materials.

18. The illumination unit of claim 1, wherein the electrical tracks are multi-layer tracks that comprise a copper layer on the substrate layer, a nickel layer arranged over the copper layer, and a gold layer over the nickel layer.

19. The illumination unit of claim 1, wherein each of the solid-state light generating sources is arranged on the substrate along the electrical tracks using a surface mount technology.

20. The illumination unit of claim 1, wherein the illumination unit is a display unit.

21. The illumination unit of claim 1, wherein the illumination unit is used to deliver light energy to the skin of a patient for phototherapy.

22. The illumination unit of claim 1, wherein the encapsulant is sufficiently thick such that the unit is flexible while providing adequate phototherapy to patient of the unit without harming the patient.