Computer LED bar and thermal architecture features

• US 9,207,484 B2
• Filed: 09/26/2012
• Issued: 12/08/2015
• Est. Priority Date: 09/26/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hendren, Keith J., Mathew, Dinesh C., Rundle, Nicholas Alan, Degner, Brett W.
• Primary Examiner(s): NGUYEN, DUNG T
• Application Number:
  US13/628,005
• Publication Number:
  US 20140085564A1
• Time in Patent Office: 1,168 Days
• Field of Search: 349 58- 60, 349/72, 349/161
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133308 Support structures for LCD panels, e.g. frames or bezels
• CPC Class Codes: G02F 1/133382 Heating or cooling of liquid crystal cells other than for activation, e.g. circuits or arrangements for temperature control, stabilisation or uniform distribution over the cell
• CPC Class Codes: G02F 1/133385 with cooling means, e.g. fans
• CPC Class Codes: G02F 1/133628 with cooling means

Abstract

The described embodiments relate generally to liquid crystal displays (LCDs) and more particularly to thermal management of heat produced by an illumination source in an LCD module. High temperatures generated by the illumination source can cause color shifts in the LCD due to changes in any included LEDs and liquid crystals. One solution is to house the LCD module in a metal chassis and thermally couple the LED light bar to the metal chassis. Furthermore, the LCD module can be kept at a uniform temperature by transferring heat from a region near the LED light bar to a relatively cooler region of the LCD module. These approaches can minimize any alterations or shifts in color resulting from heat from the LED light bar.

Claims

1. A computing device, comprising:

a chassis formed of a thermally conductive material and configured to support operating components;

a liquid crystal display (LCD) module having a proximal edge and distal edge opposite the proximal edge, the LCD module comprising;

an illumination source located proximate to the proximal edge and configured to provide light and heat,

a light guide configured to receive and internally disperse at least some of the light provided by the illumination source, and

an LCD cell configured to receive at least some of the internally dispersed light from the light guide, wherein the LCD cell comprises liquid crystals and a color filter, wherein the liquid crystals respond to a control signal by passing at least some of the internally dispersed light received from the light guide to the color filter; and

a cover glass layer disposed proximate to the LCD cell;

wherein the chassis has regions of varying thickness that preferentially distributes the heat generated by the illumination source from the proximal edge toward the distal edge of the LCD module.

2. The computing device as recited in claim 1, wherein the illumination source further comprises:

a thermally conductive substrate;

LED lights thermally coupled to one surface of the thermally conductive substrate; and

electrical traces overlaid on the thermally conductive substrate and configured to deliver power to the LED lights.

3. The computing device as recited in claim 1, further comprising a graphite layer disposed along a surface of the chassis and thermally coupled to the illumination source, wherein the graphite layer is configured to anisotropically conduct the heat away from the illumination source by preferentially conducting the heat along a length of graphite layer.

4. The computing device as recited in claim 1, further comprising cooling fins configured to increase convection of the heat away from the illumination source.

5. The computing device as recited in claim 4, wherein the cooling fins is attached to a heat sink coupled to one or more LED lights.

6. The computing device as recited in claim 1, further comprising at least one heat pipe thermally coupled to the illumination source and configured to transfer the heat from the illumination source toward the distal edge of the LCD module.

7. The computing device as recited in claim 1, further comprising at least one electrical component thermally coupled to the LCD module and disposed proximate to the distal edge of the LCD module.

8. The computing device as recited in claim 1, further comprising:

a mounting frame that attaches the cover glass layer to the chassis, wherein the mounting frame and the cover glass layer are configured to inhibit a flow of heat between the chassis and the LCD display module.

9. The computing device as recited in claim 1, wherein the chassis includes a thick region and a thin region, wherein the thick region transfers more of the heat toward the distal edge than the thin region.

10. The computing device as recited in claim 1, further comprising:

an exterior housing configured to enclose the chassis and LCD module;

an inlet disposed in a first surface of the exterior housing;

an outlet disposed in a second surface of the exterior housing, wherein the inlet and outlet are configured such that an airflow moving from the inlet to the outlet distributes a portion of the heat from the illumination source from the proximal edge toward the distal edge; and

a cooling fan configured to move air through the exterior housing from the inlet to the outlet.

11. The computing device as recited in claim 10, further comprising:

at least one temperature sensor configured to detect a temperature of the illumination source; and

a controller configured to receive data from the at least one temperature sensor and control a rotation speed of the fan to keep the illumination source within a pre-defined temperature range.

12. A computing device, comprising:

a display module having a proximal end and a distal end opposite the proximal end, the display module comprising;

a liquid crystal display (LCD) cell configured to display visual content of the computing device;

an illumination source configured to provide light for the LCD cell, the illumination source positioned proximate to the proximal end such that heat generated by the illumination source heats the proximal end of the display module; and

a chassis arranged to support the display module, the chassis comprising a thermally conductive material that is thermally coupled with the display module, wherein the chassis has regions of varying thickness that distribute the heat generated by the illumination source from the proximal end preferentially toward the distal end of the display module.

13. The computing device of claim 12, wherein the preferential distribution of the heat maintains a temperature of the display module within an operating temperature range.

14. The computing device of claim 12, wherein the heat is preferentially distributed toward a first corner and a second corner of the display of the distal end.

15. The computing device of claim 12, wherein the chassis includes a thick region and a thin region, wherein the thick region transfers more of the heat toward the distal end than the thin region.

16. The computing device of claim 12, further comprising:

a graphite layer oriented so as to anisotropically conduct the heat generated by the illumination source away from the LCD cell in a region proximate the illumination source.

17. The computing device of claim 16, wherein the heat is preferentially distributed away from a central region of the display module.

18. The computing device of claim 12, further comprising:

a mounting frame that attaches the chassis to a cover glass layer of the display module, the mounting frame and the cover glass layer configured to reduce an amount of heat flowing between the chassis and the display module.

19. The computing device of claim 12, wherein the illumination source is thermally coupled to that chassis via a metal core printed circuit board that supplies power to the illumination source.

20. The computing device of claim 12, wherein the chassis is comprised of aluminum, graphite, carbon fiber or thermally conductive thermoplastic.

21. The computing device of claim 12, wherein the computing device further comprises:

an exterior housing and a fan, the exterior housing enclosing the display module and fan therein, the exterior housing including an air inlet proximate to the proximal end of the display module and an air outlet proximate to the distal end of the display module, wherein the fan increases airflow from the air inlet to the air outlet.