Electronic Device With Heat Spreading Film

• US 20150362791A1
• Filed: 09/26/2014
• Published: 12/17/2015
• Est. Priority Date: 06/13/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Gettemy, Shawn R., Sullivan, Mark T., Chowdhury, Ihtesham H., Kakuda, Tyler R.
• Granted Patent: US 9,939,672 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F28F 2013/006 Heat conductive materials
• CPC Class Codes: G02F 1/133308 Support structures for LCD panels, e.g. frames or bezels
• CPC Class Codes: G02F 1/133317 Intermediate frames, e.g. between backlight housing and front frame
• CPC Class Codes: G02F 1/133385 with cooling means, e.g. fans
• CPC Class Codes: G02F 1/133628 with cooling means
• CPC Class Codes: H01L 2023/4068 Heatconductors between device and heatsink, e.g. compliant heat-spreaders, heat-conducting bands
• CPC Class Codes: H01L 23/34 Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements thermal treatment apparatus H01L21/00
• CPC Class Codes: H01L 23/40 Mountings or securing means for detachable cooling or heating arrangements heating H01L23/345; fixed by friction, plugs or springs

Abstract

An electronic device may have a housing in which components are mounted that produce heat. The heat producing components may be light-emitting diodes mounted on a flexible printed circuit in a display backlight, may be integrated circuits, or may be other devices that generate heat during operation. A heat spreading layer such as a layer of graphite may be attached to the backlight unit or other structures in the electronic device using adhesive. The adhesive may be patterned to form an unbonded area between at least some of the backlight unit or other structures to which the heat spreading layer is being attached and the heat spreading layer. The heat spreading layer may be mounted adjacent to a housing structure such as a metal midplate member that is attached to housing walls in the housing.

Claims

1. A display, comprising:

display layers including a layer of liquid crystal material; and

backlight structures that supply backlight that passes through the display layers; and

a heat spreading layer that is attached to the backlight structures.

2. The display defined in claim 1 wherein the heat spreading layer comprises a layer of graphite.

3. The display defined in claim 1 wherein the heat spreading layer comprises a layer of copper.

4. The display defined in claim 1 wherein the heat spreading layer includes adhesive that attaches the heat spreading layer to the backlight structures, wherein the adhesive is patterned to form an unbonded area between at least some of the heat spreading layer and the backlight structures.

5. The display defined in claim 4 wherein the backlight structures include a light guide plate and a reflector and wherein the adhesive attaches the heat spreading layer to the backlight structures so that the reflector is interposed between the heat spreading layer and the light guide plate.

6. The display defined in claim 5 further comprising:

light-emitting diodes that supply light to the light guide plate; and

a flexible printed circuit on which the light-emitting diodes are mounted.

7. The display defined in claim 6 further comprising light blocking tape that is attached to the flexible printed circuit and the reflector.

8. The display defined in claim 7 wherein the light blocking tape is interposed between the heat spreading structures and the flexible printed circuit.

9. The display defined in claim 8 wherein the adhesive includes adhesive selected from the group consisting of:

a C-shape strip of adhesive, an array of adhesive patches, a cross-shaped region of adhesive, and parallel strips of adhesive.

10. An electronic device, comprising:

a housing that includes a metal midplate member;

display layers including a layer of liquid crystal material;

backlight structures that supply backlight that passes through the display layers; and

a heat spreading layer that is attached to the backlight structures and that is separated from the metal midplate member by an air gap.

11. The electronic device defined in claim 10 wherein the heat spreading layer comprises:

at least one polymer layer;

a layer of graphite on the polymer layer;

adhesive that attaches the heat spreading layer to the backlight structures.

12. The electronic device defined in claim 11 wherein the backlight structures comprise:

light-emitting diodes on a flexible printed circuit; and

a reflector.

13. The electronic device defined in claim 12 wherein the adhesive forms a strip that runs along at least one edge of the backlight structures and creates an unbonded area between the heat spreading layer and the backlight structures.

14. The electronic device defined in claim 13 wherein the backlight structures comprise a chassis, wherein the backlight structures include a light guide plate that receives light from the light-emitting diodes, and wherein the light guide plate and the reflector are mounted in the chassis.

15. The electronic device defined in claim 14 wherein at least some of the adhesive is attached to the chassis.

16. Apparatus, comprising:

a flexible structure that is supplied with heat in an electronic device; and

a heat spreading layer having adhesive that is patterned to attach the heat spreading layer to the flexible structure so that there is at least one unbonded region between flexible structure and the heat spreading layer that is free of adhesive.

17. The apparatus defined in claim 16 wherein the flexible structure comprises an organic light-emitting diode display.

18. The apparatus defined in claim 17 wherein the heat spreading layer includes a layer of graphite.

19. The apparatus defined in claim 16 wherein the flexible structure comprises a flexible printed circuit in a backlight unit, wherein the backlight unit includes light-emitting diodes on the flexible printed circuit, a light guide plate, and a reflector, and wherein the apparatus further comprises light-blocking tape attached to the flexible printed circuit and the reflector.

20. The apparatus defined in claim 19 wherein the adhesive attaches the heat spreading layer to the backlight unit so that the flexible printed circuit overlaps the heat spreading layer, the apparatus further comprising a stainless steel plate that is separated from the heat spreading layer by an air gap.