Differently oriented layered thermal conduit
10299407 ยท 2019-05-21
Assignee
Inventors
- Erin Hurbi (San Francisco, CA, US)
- Michael Nikkhoo (Saratoga, CA, US)
- Douglas L. Heirich (Palo Alto, CA, US)
Cpc classification
H01L23/373
ELECTRICITY
H01L2023/4068
ELECTRICITY
F28F2013/001
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F28F21/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
H05K7/20509
ELECTRICITY
F28F2255/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
H01L23/3733
ELECTRICITY
F28D2021/0028
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
H05K7/20
ELECTRICITY
F28F21/02
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A thermal conduit configured to conduct heat from a heat source to a heat sink and method of forming said conduit are disclosed herein. The thermal conduit may comprise a plurality of stacked sheets formed of an anisotropically thermally conductive material, a non-limiting example of which is graphite, each sheet with a respective orientation of thermal conduction. The orientations of thermal conduction of the plurality of sheets may change stepwise in a stacking direction to form a curved thermal flow path.
Claims
1. A thermal conduit configured to conduct heat from a heat source to a heat sink, the conduit comprising: a plurality of stacked sheets formed of an anisotropically thermally conductive material, each sheet with two respective a-axes of thermal conduction and a respective c-axis along which the anisotropically thermally conductive material has a lower thermal conductivity compared to the a-axes, each sheet having an angle between a plane of that sheet and a plane of thermal conduction defined by the a-axes of that sheet; wherein, for at least one sheet of the plurality of stacked sheets, the angle of the sheet differs stepwise in a stacking direction relative to at least one corresponding angle of an adjacent sheet in the plurality of stacked sheets to form a curved thermal flow path.
2. The thermal conduit of claim 1, wherein the anisotropically thermally conductive material is graphite.
3. The thermal conduit of claim 1, wherein the plurality of stacked sheets are slices from blocks of the anisotropically thermally conductive material that have been sliced at corresponding angles and stacked such that the planes of thermal conduction of the one sheet and the adjacent sheet change stepwise in the stacking direction.
4. The thermal conduit of claim 1, wherein the curved thermal flow path comprises at least a first curve from the heat source to a mid portion of the thermal conduit and a second curve from the mid portion to the heat sink.
5. The thermal conduit of claim 4, wherein the heat source is a first heat source, the thermal conduit further comprising an introduction path to conduct heat from a second heat source to the heat sink, the introduction path including a third curve and merging with the curved thermal flow path.
6. The thermal conduit of claim 4, wherein the plurality of stacked sheets are formed in a plurality of stacks arranged orthogonally relative to the stacking direction, and the planes of thermal conduction of at least some of the sheets at corresponding positions in the stacking direction in neighboring stacks are different from each other.
7. The thermal conduit of claim 1, at least a portion of which has an elongated rectangular shape.
8. The thermal conduit of claim 1, wherein the curved thermal flow path traverses the thermal conduit in three dimensions.
9. The thermal conduit of claim 1, wherein the heat source is a heat generating component mounted in a head-mounted display (HMD) device and the heat sink is a heat dissipating component mounted in the HMD device.
10. The thermal conduit of claim 1, wherein: of the plurality of stacked sheets, an entry sheet adjacent to the heat source is configured such that the c-axis of the entry sheet forms an entry angle with an adjacent surface of the heat source that is greater than 0 and less than 90.
11. A method of forming a thermal conduit configured to conduct heat from a heat source to a heat sink, the method comprising: stacking a plurality of sheets formed of an anisotropically thermally conductive material, each sheet with two respective a-axes of thermal conduction and a respective c-axis along which the anisotropically thermally conductive material has a lower thermal conductivity compared to the a-axes, each sheet having an angle between a plane of that sheet and a plane of thermal conduction defined by the a-axes of that sheet; and for at least one sheet of the plurality of stacked sheets, changing the angle of the sheet stepwise in a stacking direction relative to at least one corresponding angle of an adjacent sheet in the plurality of stacked sheets to form a curved thermal flow path through the thermal conduit.
12. The method of claim 11, wherein the anisotropically thermally conductive material is graphite.
13. The method of claim 11, further comprising: slicing the plurality of sheets from blocks of the anisotropically thermally conductive material at corresponding angles to give each sheet the respective plane of thermal conduction.
14. The method of claim 11, wherein the curved thermal flow path comprises at least a first curve from the heat source to a mid portion of the thermal conduit and a second curve from the mid portion to the heat sink.
15. The method of claim 11, wherein the heat source is a first heat source, the method further comprising forming an introduction path to conduct heat from a second heat source to the heat sink, the introduction path including a third curve and merging with the curved thermal flow path.
16. The method of claim 11, further comprising: forming the plurality of stacked sheets in a plurality of stacks arranged orthogonally relative to the stacking direction; wherein the planes of thermal conduction of at least some of the sheets at corresponding positions in the stacking direction in neighboring stacks are different from each other.
17. The method of claim 11, wherein the curved thermal flow path traverses the thermal conduit in three dimensions.
18. The method of claim 11, wherein the heat source is a heat generating component mounted in a head-mounted display (HMD) device and the heat sink is a heat dissipating component mounted in the HMD device.
19. The method of claim 11, the method further comprising configuring, of the plurality of stacked sheets, an entry sheet adjacent to the heat source such that the c-axis of the entry sheet forms an entry angle with an adjacent surface of the heat source that is greater than 0 and less than 90.
20. A thermal conduit configured to conduct heat from a heat source to a heat sink, the conduit comprising: a plurality of stacked sheets formed of an anisotropically thermally conductive material, each sheet with two respective a-axes of thermal conduction and a respective c-axis along which the anisotropically thermally conductive material has a lower thermal conductivity compared to the a-axes, each sheet having an angle between a plane of that sheet and a plane of thermal conduction defined by the a-axes of that sheet; wherein: for at least one sheet of the plurality of stacked sheets, the angle of the sheet differs stepwise in a stacking direction relative to at least one corresponding angle of an adjacent sheet in the plurality of stacked sheets to form a curved thermal flow path; the anisotropically thermally conductive material is graphite; and the heat source is a heat generating component mounted in a head-mounted display (HMD) device and the heat sink is a heat dissipating component mounted in the HMD device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
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(10) A plurality of sheets 12 may be slices from the block(s) 10 of the anisotropically thermally conductive material that have been sliced at corresponding angles. When the anisotropically thermally conductive material is graphite, the blocks 10 may be formed by layering graphene. The area of the block 10 at which each example sheet 12 is cut is shown in dashed lines. The corresponding angle at which the sheets 12 are sliced from the block(s) 10 may determine an orientation of thermal conduction of each sheet 12. The sheets 12 may be sliced at any angle and are not limited to the angles shown in the example of
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(12) The conduit 14 may comprise a plurality of the stacked sheets 12 formed of the anisotropically thermally conductive material, each sheet with a respective orientation of thermal conduction. When the sheets 12 with varying orientations are stacked up and pressure is applied to join them together, the orientations of thermal conduction of the plurality of sheets 12 may change stepwise in the stacking direction to form a curved thermal flow path 20. The stacking direction of the sheets 12 in
(13) As the height of the conduit 14 may be very short compared to the length, some portions of
(14) As shown in
(15) The first curve 22 may be formed in a single stack 28 after the heat source 16 and before the mid portion 24, or the conduit 14 may comprise one or more additional stacks 28 to gradually direct the thermal flow path from the heat source 16 into the mid portion 24, as shown in
(16) As mentioned above, each sheet 12 of the plurality of sheets 12 may comprise a c-axis along which the anisotropically thermally conductive material has a relatively low thermal conductivity compared to at least an a-axis of the sheet 12. Of the plurality of sheets 12, an entry sheet 12A adjacent to the heat source 16 may be configured such that its c-axis forms an entry angle 30 with an adjacent surface 16A of the heat source 16 that is greater than 0 and less than 90. The entry angle 30 shown in
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(20) The thermal conduit 14 may be utilized in a variety of applications, including various types of computing devices.
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(22) With reference to
(23) At 810, the thermal flow path may comprise at least a first curve from the heat source to a mid portion of the thermal conduit and a second curve from the mid portion to the heat sink. The mid portion may be substantially uniform in shape and/or orientation of thermal conduction, and heat traversing the mid portion may do so comparatively quickly due to the low thermal resistance along the c-axis of the mid portion. At 812, the heat source may be a first heat source, and the method 800 may include forming an introduction path to conduct heat from a second heat source to the heat sink, the introduction path including a third curve and merging with the thermal flow path. In order to accommodate the introduction path, the thermal flow path may slightly curve away from the introduction path before they merge downstream.
(24) At 814, the method 800 may include forming the plurality of stacked sheets in a plurality of stacks arranged orthogonally relative to the stacking direction. Utilizing a plurality of stacks may allow for a greater degree of customization of the thermal flow path, as more curves can be formed and more heat sources or heat sinks can be connected to the conduit. At 816, the orientation of thermal conduction of at least some of the sheets at corresponding positions in the stacking direction in neighboring stacks may be different from each other. This may allow for lateral curving between stacks, gradual curves that extend over multiple stacks, and fine control over the shape of the thermal flow path. At 818, the thermal flow path may traverse the thermal conduit in three dimensions.
(25) At 820, the heat source may be a heat generating component mounted in a head-mounted display (HMD) device and the heat sink may be a heat dissipating component mounted in the HMD device. As HMD devices generate a great amount of heat and have sensitive components, the thermal conduit may keep the HMD device cool, light, and running at acceptable performance levels. At 822, each sheet of the plurality of sheets may comprise a c-axis along which the anisotropically thermally conductive material has a relatively low thermal conductivity compared to at least an a-axis of the sheet. At 824, the method 800 may include configuring, of the plurality of sheets, an entry sheet adjacent to the heat source such that its c-axis forms an entry angle with an adjacent surface of the heat source that is greater than 0 and less than 90.
(26) A thermal conduit consisting of an anisotropically thermally conductive material has been disclosed herein. The conduit may be tailor made to efficiently conduct heat from one or more heat source to one or more heat sink, taking into account the specific spatial arrangement of the components providing and receiving the heat. This configuration may reduce the thermal resistance into and out of the plane of the conduit that uniform graphite, for example, experiences.
(27) The subject matter of the present disclosure is further described in the following paragraphs. One aspect provides a thermal conduit configured to conduct heat from a heat source to a heat sink, the conduit comprising a plurality of stacked sheets formed of an anisotropically thermally conductive material, each sheet with a respective orientation of thermal conduction, wherein the orientations of thermal conduction of the plurality of sheets change stepwise in a stacking direction to form a curved thermal flow path. In this aspect, the anisotropically thermally conductive material may be graphite. In this aspect, the plurality of sheets may be slices from blocks of the anisotropically thermally conductive material that have been sliced at corresponding angles and stacked such that the orientations of thermal conduction change stepwise in the stacking direction. In this aspect, the thermal flow path comprises at least a first curve from the heat source to a mid portion of the thermal conduit and a second curve from the mid portion to the heat sink. In this aspect, the heat source is a first heat source, the thermal conduit further comprising an introduction path to conduct heat from a second heat source to the heat sink, the introduction path including a third curve and merging with the thermal flow path. In this aspect, the plurality of stacked sheets are formed in a plurality of stacks arranged orthogonally relative to the stacking direction, and the orientation of thermal conduction of at least some of the sheets at corresponding positions in the stacking direction in neighboring stacks are different from each other. In this aspect, at least a portion of the thermal conduit may have an elongated rectangular shape. In this aspect, the thermal flow path may traverse the thermal conduit in three dimensions. In this aspect, the heat source may be a heat generating component mounted in a head-mounted display (HMD) device and the heat sink may be a heat dissipating component mounted in the HMD device. In this aspect, each sheet of the plurality of sheets may comprise a c-axis along which the anisotropically thermally conductive material has a relatively low thermal conductivity compared to at least an a-axis of the sheet, and of the plurality of sheets, an entry sheet adjacent to the heat source may be configured such that its c-axis forms an entry angle with an adjacent surface of the heat source that is greater than 0 and less than 90.
(28) According to another aspect, a method of forming a thermal conduit configured to conduct heat from a heat source to a heat sink may comprise stacking a plurality of sheets formed of an anisotropically thermally conductive material, each sheet with a respective orientation of thermal conduction, and changing the orientations of thermal conduction of the plurality of sheets stepwise in a stacking direction to form a curved thermal flow path through the thermal conduit. In this aspect, the anisotropically thermally conductive material may be graphite. In this aspect, the method may further comprise slicing the plurality of sheets from blocks of the anisotropically thermally conductive material at corresponding angles to give each sheet the respective orientation of thermal conduction. In this aspect, the thermal flow path may comprise at least a first curve from the heat source to a mid portion of the thermal conduit and a second curve from the mid portion to the heat sink. In this aspect, the heat source may be a first heat source, and the method may further comprise forming an introduction path to conduct heat from a second heat source to the heat sink, the introduction path including a third curve and merging with the thermal flow path. In this aspect, the method may further comprise forming the plurality of stacked sheets in a plurality of stacks arranged orthogonally relative to the stacking direction, wherein the orientation of thermal conduction of at least some of the sheets at corresponding positions in the stacking direction in neighboring stacks are different from each other. In this aspect, the thermal flow path may traverse the thermal conduit in three dimensions. In this aspect, the heat source may be a heat generating component mounted in a head-mounted display (HMD) device and the heat sink may be a heat dissipating component mounted in the HMD device. In this aspect, each sheet of the plurality of sheets may comprise a c-axis along which the anisotropically thermally conductive material has a relatively low thermal conductivity compared to at least an a-axis of the sheet, and the method may further comprise configuring, of the plurality of sheets, an entry sheet adjacent to the heat source such that its c-axis forms an entry angle with an adjacent surface of the heat source that is greater than 0 and less than 90.
(29) According to another aspect, a thermal conduit may be configured to conduct heat from a heat source to a heat sink, the conduit comprising a plurality of stacked sheets formed of an anisotropically thermally conductive material, each sheet with a respective orientation of thermal conduction, wherein the orientations of thermal conduction of the plurality of sheets change stepwise in a stacking direction to form a curved thermal flow path, the anisotropically thermally conductive material is graphite, and the heat source is a heat generating component mounted in a head-mounted display (HMD) device and the heat sink is a heat dissipating component mounted in the HMD device.
(30) It will be understood that the configurations and/or approaches described herein are exemplary in nature, and that these specific embodiments or examples are not to be considered in a limiting sense, because numerous variations are possible. The specific routines or methods described herein may represent one or more of any number of processing strategies. As such, various acts illustrated and/or described may be performed in the sequence illustrated and/or described, in other sequences, in parallel, or omitted. Likewise, the order of the above-described processes may be changed.
(31) The subject matter of the present disclosure includes all novel and nonobvious combinations and subcombinations of the various processes, systems and configurations, and other features, functions, acts, and/or properties disclosed herein, as well as any and all equivalents thereof.