JP3180462U - Thermal device kit for smart device and smart device - Google Patents

Abstract

A heat dissipating member kit for a smart device and its heat dissipating member kit, which has a simple structure and can be easily mounted and assembled on a heat generating part while maintaining basic heat transfer and heat dissipating properties as a heat sink. Provide smart devices with attached.
A smart device 1A formed using a heat dissipation member kit including a heat dissipation member 2 made of an alumina sintered body and an aluminum adhesive tape 4 for fixing the heat dissipation member 2 to a device body 12. . The heat dissipating member 2 is disposed at a position overlapping the heat generating portion of the device main body 12 and is fixed to the device main body 12 by an aluminum adhesive tape 4 so as to contact the outer surface of the back cover 6. .
[Selection] Figure 1C

Description

  The present invention relates to a heat radiating member kit for radiating heat generated from built-in components such as a CPU and a battery to the outside of a smart device such as a smartphone and a tablet terminal, and a smart device to which the heat radiating member kit is attached. .

  Electronic and electrical devices such as mobile phones and personal computers incorporate a large number of components (hereinafter referred to as “heat generating components”) that generate heat as the devices operate, such as CPUs and batteries. The heat generated in the heat generating component is not desirable because it causes malfunction or forced termination of the device, deterioration or failure of the heat generating component or other built-in components, and failure of the entire device.

  Therefore, the device is devised to prevent heat generation as much as possible and to radiate heat inevitably generated to the outside of the device. For example, a method is known in which an air cooling fan or a water cooling fan is installed inside the device, and heat is radiated to the outside of the device by these fans.

  However, when the above method is adopted, in addition to the fan itself being bulky, it is necessary to separately install a fan drive mechanism. Accordingly, the application target of the method is limited to a personal computer or the like that has a relatively large space in the internal space of the device and can tolerate a certain increase in weight. In other words, in smart devices such as smartphones and tablet terminals that are desired to be small, thin, and lightweight, the internal space of the device is not so large and the increase in weight is disliked, so it is realistic to install an air cooling fan or the like. It is not an option.

  Therefore, in smart devices, a method has been proposed in which a radiator (heat sink) is installed in the device and heat is radiated to the outside of the device by the radiator.

  For example, an alumina plate mainly composed of an alumina material having an emissivity of 0.8 or more is laminated on a metal plate to form a cooling device (heat radiator), and the cooling device is mounted on the surface of a core of a semiconductor integrated circuit. A cooling device is disclosed that radiates and cools the semiconductor integrated circuit by applying a load to the alumina plate (Patent Document 1).

JP 2010-251432 A

  However, since the cooling device described in Patent Document 1 is used with a load applied to the alumina plate (heat radiating plate), parts such as weights and weight supports are required, and the structure of the entire device is complicated. Moreover, it cannot be said that it is easy to attach and assemble the semiconductor integrated circuit (heat generating portion). In other words, when considering application to a small, thin, and lightweight device such as a smart device, the conventional heatsink still has problems to be solved in terms of simplification of the structure and ease of installation and assembly. there were.

  The present invention has been made to solve the problems of the prior art. That is, the present invention has a heat dissipation member kit for a smart device that is simple in structure and easy to attach and assemble to a heat generating part while maintaining the heat conductivity and heat dissipation, which are basic performances as a heat sink, and the above-mentioned A smart device having a heat dissipating member kit attached thereto is provided.

  The present inventors diligently studied about the above problem. As a result, the heat dissipating member made of an alumina sintered body is attached to the outer surface of the back cover of the device body, or the heat dissipating member made of an alumina sintered body and having a flange is formed in the opening formed in the back cover in advance. The present invention has been completed by conceiving that the above problem can be solved by fitting from the inside of the back cover.

  That is, according to the present invention, there is provided a heat radiating member kit for a smart device, comprising: a heat radiating member made of an alumina sintered body; and an aluminum adhesive tape for fixing the heat radiating member to a device body. Provided.

  In the heat dissipation member kit according to the present invention, the heat dissipation member preferably has a thermal conductivity of 30 to 60 W / m · K and a thermal emissivity of 0.93 to 0.99.

  Further, in the heat dissipation member kit according to the present invention, the alumina sintered body has an alumina content of 99.0% by mass or more, a silica content of 0.1% by mass or less, and a crystal grain size of 1 to 10 μm. And it is preferable to contain 20 to 65 crystal grains in an area of 30 × 20 μm.

  Furthermore, in the heat dissipation member kit according to the present invention, the alumina sintered body has an alumina content of 99.5% by mass or more, a silica content of 0.1% by mass or less, and a crystal grain size of 1 to 5 μm. And it is preferable that it contains 100 to 180 crystal grains in an area of 30 × 20 μm.

  According to the present invention, a smart device formed using the heat dissipation member kit, wherein the heat dissipation member is disposed at a position overlapping the heat generating portion of the device body, and the aluminum adhesive tape A smart device is provided that is fixed to the device main body so as to abut against the outer surface of the back cover.

  In the smart device according to the present invention, it is preferable that the heat generating portion is a portion where at least one component selected from a group of a CPU and a battery is disposed.

  According to the present invention, a heat radiation member made of an alumina sintered body and having a heat radiation member main body and a flange projecting around the bottom surface of the heat radiation member main body, and an opening having a shape capable of fitting the heat radiation member main body are formed. There is provided a heat dissipating member kit for a smart device, comprising a back cover of the device main body.

  In the heat dissipation member kit according to the present invention, the heat dissipation member preferably has a thermal conductivity of 30 to 60 W / m · K and a thermal emissivity of 0.93 to 0.99.

  Further, in the heat dissipation member kit according to the present invention, the alumina sintered body has an alumina content of 99.0% by mass or more, a silica content of 0.1% by mass or less, and a crystal grain size of 1 to 10 μm. And it is preferable to contain 20 to 65 crystal grains in an area of 30 × 20 μm.

  Furthermore, in the heat dissipation member kit according to the present invention, the alumina sintered body has an alumina content of 99.5% by mass or more, a silica content of 0.1% by mass or less, and a crystal grain size of 1 to 5 μm. And it is preferable that it contains 100 to 180 crystal grains in an area of 30 × 20 μm.

  According to the present invention, there is provided a smart device formed using the heat dissipation member kit, wherein the heat dissipation member is disposed at a position overlapping the heat generating portion of the device body, and the flange portion is the back cover. The smart device is arranged on the inner side of the device, and is fixed to the device main body so that the flange portion contacts the inner surface of the back cover by fitting the heat radiating member main body into the opening. A device is provided.

  In the smart device according to the present invention, it is preferable that the heat generating portion is a portion where at least one component selected from a group of a CPU and a battery is disposed.

  The heat dissipating member kit according to the present invention has a simple structure while maintaining the heat conductivity and heat dissipating properties, which are basic performances as a heat sink, and can be easily mounted and assembled on a heat generating portion.

  In addition, the smart device according to the present invention is excellent in thermal conductivity and heat dissipation, and can effectively prevent malfunction or forced termination due to heat, deterioration or failure of built-in components, and thus failure of the entire device.

1 is a schematic perspective view schematically showing an embodiment of a smart device according to the present invention. FIG. 1B is a schematic plan view schematically showing the smart device shown in FIG. 1A as viewed from above. It is a schematic end view which shows typically the A-A 'end surface of the smart device shown to FIG. 1B. It is a schematic perspective view which shows typically another embodiment of the smart device which concerns on this invention. FIG. 2B is a schematic plan view schematically showing the smart device shown in FIG. 2A as viewed from above. FIG. 3 is a schematic end view schematically showing a B-B ′ end face of the smart device shown in FIG. 2B. It is a schematic plan view which shows typically the state which looked at the thermal radiation member shown to FIG. 2A from upper direction. FIG. 2D is a schematic end view schematically showing a C-C ′ end face of the heat dissipation member shown in FIG. 2D. It is a figure of the electron micrograph which shows the crystal state of the alumina sintered compact (1) shown in Table 1. It is a figure of the electron micrograph which shows the crystal state of the alumina sintered compact (6) shown in Table 1.

  Hereinafter, a heat radiating member kit (hereinafter simply referred to as “heat radiating member kit”) for a smart device and a smart device according to the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment, and includes all objects having specific matters.

[1] Definitions etc .:
“Smart device” means an information processing terminal (device) that is a multi-function terminal in which an OS is installed. Specifically, a smartphone (multifunctional mobile phone / PHS), a tablet terminal, and the like can be given. The smart device 1A shown in FIGS. 1A to 1C and the smart device 1B shown in FIGS. 2A to 2C are both smartphones. In the present specification, for convenience of explanation, the smart device before the heat radiating member is attached may be referred to as a “device body”.

  The “back cover” means a cover that constitutes a back portion of the device main body and covers built-in components of the device main body. The specific structure is not particularly limited. For example, the device main body 12 shown in FIGS. 1A to 1C and the device main body 13 shown in FIGS. 2A to 2C include surface panels 8 and 9 on which a display and various built-in components are installed. It is further provided with rear covers 6 and 7 that are attached to the side and cover and protect the rear surfaces of the front panels 8 and 9.

  The “heat generating portion” refers to a portion where a component (heat generating component) that generates heat when the device is used is disposed among the built-in components of the smart device. Examples of the heat generating component include a CPU and a battery, and a portion where these components are arranged becomes a heat generating portion. In FIG. 1C and FIG. 2C, the portion where the CPU and the battery are arranged is schematically displayed as the heat generating portions 10 and 11 integrally.

  The “heat dissipating member kit” means a set of a heat dissipating member that imparts heat dissipation to the device body and a fixing member for fixing the heat dissipating member to the device body. As the heat radiating member, an alumina sintered body excellent in thermal conductivity, thermal radiation, and electrical insulation is used.

[2] First embodiment:
1st Embodiment of the smart device which concerns on this invention is a form which affixes the thermal radiation member 2 on the outer surface of the back cover 6 of the device main body 12 like the smart device 1A shown to FIG. 1A-FIG. 1C.

[2-1] Heat dissipation member kit:
The heat dissipation member kit according to the first embodiment includes a heat dissipation member made of an alumina sintered body, and an aluminum adhesive tape that fixes the heat dissipation member to the device body.

  As long as the said structure is satisfy | filled, the structure of a heat radiating member kit is not specifically limited. For example, in the case of the heat radiating member kit for configuring the smart device 1A shown in FIGS. 1A to 1C, the three heat radiating members 2a, 2b, 2c and the heat radiating members 2a, 2b that impart heat radiating properties to the device body 12 are provided. , 2c may be configured as a set of aluminum adhesive tape 4 for fixing to the device body 12.

[2-2] Smart device:
The smart device according to the first embodiment is a smart device formed using the heat dissipation member kit. And as the smart device 1A shown to FIG. 1A-FIG. 1C, while the heat radiating member 2 is arrange | positioned in the position which overlaps with the heat-emitting part 10 of the device main body 12, it is formed in the outer surface of the back cover 6 with the aluminum adhesive tape 4. It is fixed to the device main body 12 so as to abut.

[2-3] Heat dissipation member:
In the first embodiment, it is preferable that the contact portion of the device main body with the outer surface of the back cover has a planar shape so that the device main body is in close contact with the outer surface of the back cover. For example, the shape of the heat dissipation member 2 shown in FIGS. 1A to 1C is a flat plate. The flat plate has a simple shape and is easy to manufacture. In addition, the flat plate can be easily brought into close contact with the outer surface of the back cover 6 of the device main body 12, and high thermal conductivity and a heat dissipation effect can be obtained.

  However, the shape of the heat dissipation member is not limited to a flat plate. For example, it is good also as a shape where the corner | angular part by the side of the upper surface (surface opposite to the surface contact | abutted with the outer surface of the back cover 6) similar to the heat radiating member 2 is C chamfering or R chamfering. If it is the said shape, it is easy to make it closely_contact | adhere with respect to the back cover 6 of the device main body 12 similarly to the heat radiating member 2 which is flat plate shape, and can obtain high thermal conductivity and a thermal radiation effect.

  In the present invention, an alumina sintered body having excellent thermal conductivity and thermal emissivity is used as the heat radiating member. Therefore, it is not necessary to form a complicated shape such as forming a large number of heat radiation fins as in a normal heat sink.

  The thickness of the heat dissipation member is not particularly limited. However, in order not to impair the small, thin, and lightweight characteristics of the smart device, it is preferable that the heat dissipation member is thin. For example, the heat dissipation member 2 shown in FIGS. 1A to 1C is configured to be slightly thinner than the device body 12. On the other hand, in order to exhibit thermal conductivity and thermal radiation, it is preferable that the heat dissipation member has a certain thickness. Considering the above, it is more preferable that the thickness of the heat dissipation member is 3 to 7 mm.

  The number of heat dissipating members is not limited to one and may be plural. By dividing the heat dissipating member into a plurality of parts, it is easy to arrange the heat dissipating member according to the shape of the device body and the position of the heat generating part. For example, the smart device 1A shown in FIGS. 1A to 1C has three heat dissipating members 2a, 2b, and 2c. On the other hand, in order to facilitate the arrangement and fixing of the heat radiating members, it is preferable that the number of heat radiating members is small. Considering the above, the number of heat dissipation members is preferably 1 to 4, more preferably 1 to 3.

  In the smart device 1A, the three heat radiating members 2a, 2b, and 2c are configured as flat plates having the same thickness, shape, and size. However, the thickness, shape, and size of the plurality of heat dissipating members are not necessarily uniform. That is, each heat radiating member may have a different thickness, shape, and size.

  The size (width, length) of the heat dissipation member is not particularly limited. However, it is preferable to configure the heat dissipation member so that the bottom area of the heat dissipation member (that is, the area of the portion in contact with the outer surface of the back cover) is smaller than the outer surface area of the back cover. For example, in the smart device 1A shown in FIGS. 1A to 1C, the heat radiating members 2a, 2b, and 2c are configured so that the total bottom area of the three heat radiating members 2a, 2b, and 2c is smaller than the outer surface area of the back cover 6. is doing. By comprising in such a size, the space which sticks an aluminum adhesive tape on the outer surface of a back cover is securable.

  On the other hand, it is preferable to increase the size of the heat dissipating member from the viewpoint of improving heat transfer and heat dissipation. Considering the above, the size of the heat dissipation member is preferably 20 to 50%, more preferably 20 to 40%, with respect to the size of the device body. Regarding the size, the same configuration can be adopted not only when a plurality of heat dissipating members 2a, 2b, and 2c as shown in FIGS. 1A to 1C are disposed but also when a single heat dissipating member is disposed. .

[2-4] Aluminum adhesive tape:
The aluminum pressure-sensitive adhesive tape is a pressure-sensitive adhesive tape including a tape base material made of aluminum foil and a pressure-sensitive adhesive layer formed on one surface of the tape base material. In the first embodiment, the aluminum adhesive tape functions as a fixing member for the heat radiating member. For example, as shown in FIGS. 1A to 1C, the aluminum adhesive tape 4 fixes the heat radiating member 2 to the back cover 6 with the bottom surface of the heat radiating member 2 and the outer surface of the back cover 6 in direct contact with each other. Can do. Moreover, since aluminum which comprises a tape base material is excellent in heat conductivity, it has a function which assists the heat conduction from the device main body 12 to the heat radiating member 2.

  In addition, the method of sticking a heat radiating member on the outer surface of a back cover using an adhesive agent without using an aluminum adhesive tape is also considered. However, this method is not preferable because an adhesive layer having low thermal conductivity is interposed between the heat radiating member and the outer surface of the back cover, which hinders thermal conductivity and heat dissipation.

  The thickness of the tape substrate is not particularly limited. However, from the viewpoint of securing the strength of the tape itself, it is preferable that the tape base material has a certain thickness, and in order to provide appropriate flexibility and bendability that facilitates fixing of the heat dissipation member, the tape base material Is preferably not too thick. Considering the above, the thickness of the tape base material is preferably 0.005 to 0.2 mm, and more preferably 0.01 to 0.1 mm.

  The size of the tape substrate is not particularly limited. What is necessary is just to select suitably so that the heat radiating member can be reliably fixed with respect to a back cover, and the area which coat | covers a heat radiating member does not become large too much.

  The kind of adhesive which comprises an adhesion layer is not specifically limited. It can be appropriately selected from conventionally known pressure-sensitive adhesives. However, since it is used for a heat radiating member, it is preferably an adhesive having high heat resistance. For example, a silicone adhesive, an acrylic adhesive, etc. can be mentioned.

  In addition, about aluminum adhesive tape, many products with which base-material tape thickness, width | variety, and an adhesive kind differ are marketed. From these commercially available products, those having a desired thickness, width and pressure-sensitive adhesive may be appropriately selected and used.

[2-5] Fixing mode:
In the smart device according to the first embodiment, the heat radiating member is fixed to the device main body with an aluminum adhesive tape so as to abut on the outer surface of the back cover. “Abutment” means that the bottom surface of the heat dissipation member and the outer surface of the back cover are in direct contact with each other without any adhesive layer or other inclusion between the bottom surface of the heat dissipation member and the outer surface of the back cover. Means.

  For example, in the smart device 1A shown in FIGS. 1A to 1C, an aluminum adhesive tape 4 is attached to the upper and side surfaces of the three heat dissipating members 2a, 2b, 2c. The aluminum adhesive tape 4 is adhered to the outer surface of the back cover 6, whereby the heat radiating members 2 a, 2 b, 2 c are fixed to the outer surface of the back cover 6. That is, there are no adhesive layers or other inclusions between the bottom surfaces of the heat radiation members 2a, 2b, 2c and the outer surface of the back cover 6, and the bottom surfaces of the heat radiation members 2a, 2b, 2c and the back cover 6 Direct contact with the surface.

  In the first embodiment, the heat dissipation member is disposed outside the back cover of the device body. “Arranged outside” means that the heat dissipating member is arranged only outside the back cover and is not arranged inside the back cover. This is different from the second embodiment described later.

  For example, as shown in FIGS. 1A to 1C, in the smart device 1 </ b> A, three heat radiating members 2 a, 2 b, and 2 c are arranged so as to be attached to the outer surface of the back cover 6. That is, it is disposed only on the outside of the back cover 6 and is not disposed on the inside of the back cover 6.

  In the first embodiment, the heat radiating member is disposed at a position overlapping the heat generating portion of the device body. “Arranged at the overlapping position” means that when the smart device is viewed from the back side in a plan view, the heat generating part and the heat radiating member of the device body are arranged so as to overlap at least partially.

  For example, as shown in FIG. 1C, in the smart device 1A, the heat generating part 10 of the device body 12 and the heat radiating members 2a, 2b, 2c are overlapped except for a portion between the heat radiating member 2a and the heat radiating members 2b, 2c. Has been placed. In order to promote heat conduction and heat dissipation from the heat generating part, it is preferable that the heat dissipating member is disposed at a position overlapping with the part where the heat generating component generating a large amount of heat is disposed, and is selected from the group of CPU and battery. More preferably, it is arranged so as to overlap with a portion where at least one component is arranged, and is arranged so as to overlap all of the heat generating portions (that is, all of the portions where heat generating components are arranged). Is particularly preferred.

  The method for attaching the aluminum adhesive tape is not particularly limited. However, in order to promote heat dissipation from the surface of the heat dissipation member, it is preferable that the area of the portion where the heat dissipation member is covered with the aluminum adhesive tape is small. More specifically, of the exposed area of the heat dissipation member, the area of the portion covered with the aluminum adhesive tape is preferably 20% or less, and more preferably 10% or less. The “exposed area” means an area obtained by subtracting the bottom surface area (the area of the portion in contact with the outer surface of the back cover) from the surface area of the entire heat radiating member.

  In the smart device 1A shown in FIGS. 1A to 1C, the shape of the heat radiating members 2a, 2b, and 2c as viewed from above is formed in a rectangular shape, and aluminum is formed along two opposing short sides of the rectangle. Adhesive tape 4 is attached, and aluminum adhesive tape 4 is attached to the outer surface of back cover 6. Such a sticking method is compared to a method of sticking an aluminum adhesive tape along the four sides of the heat radiating member, a method of sticking an aluminum adhesive tape along two opposing long sides of the rectangle, This is preferable because the area covered with the aluminum adhesive tape can be reduced without significantly reducing the fixing strength of the heat radiating member.

[3] Second embodiment:
2nd Embodiment of the smart device which concerns on this invention is like the smart device 1B shown to FIG. 2A-FIG. 2C, consists of an alumina sintered body, the heat radiating member 3 which has the collar part 3a on the back cover 7 previously. This is a form that is fitted into the formed opening 14 from the inside of the back cover 7.

[3-1] Heat dissipation member kit:
The heat radiating member kit according to the second embodiment is made of an alumina sintered body, and the heat radiating member main body and the heat radiating member having a flange extending around the bottom surface of the heat radiating member main body can be fitted into the heat radiating member main body. And a back cover of the device body in which a shape-shaped opening is formed.

  As long as the said structure is satisfy | filled, the structure of a heat radiating member kit is not specifically limited. For example, in the case of the heat radiating member kit for configuring the smart device 1B shown in FIGS. 2A to 2C, the heat radiating member 3 that imparts heat radiating property to the device body 13 and the opening 14 are formed, and the heat radiating member 3 is fixed. What is necessary is just to comprise a kit by making the back cover 7 for doing it into a set.

[3-2] Smart device:
The smart device according to the second embodiment is a smart device formed using the heat dissipation member kit. 2A to 2C, the heat radiating member 3 is disposed at a position overlapping the heat generating portion 11 of the device main body 13, and the flange portion 3a is disposed inside the back cover 7. The heat radiating member main body 3b is fixed to the device main body 13 so that the flange 3a contacts the inner surface of the back cover 7 by fitting the heat radiating member main body 3b into the opening 14.

[3-3] Heat dissipation member:
In the second embodiment, the heat dissipating member has a shape having a heat dissipating member main body and a flange projecting around the bottom surface of the heat dissipating member main body. In other words, it has a heat radiating member main body and a frame-like collar part attached so as to surround the bottom surface of the heat radiating member main body. As long as the said structure is satisfy | filled, the shape of a heat radiating member main body and a collar part is not specifically limited. However, in order to make the heat radiating member main body and the flange portion easily adhere to the heat generating portion of the surface panel, it is preferable that the contact portion with the heat generating portion has a planar shape. For example, the shapes of the heat radiating member main body 3b and the flange 3a shown in FIGS. 2A to 2E are both flat plates. The flat plate has a simple shape and can be easily manufactured, and can be easily brought into close contact with the heat generating portion 11 of the device main body 13 to obtain high thermal conductivity and heat dissipation effect.

  Moreover, it is preferable that the bottom face of the heat radiating member main body and the bottom face of the collar part form a continuous plane. For example, in the heat radiating member 3 shown in FIGS. 2A to 2E, the bottom surface of the heat radiating member main body 3b and the bottom surface of the flange portion 3a are formed to be flush with each other (flat with no step), and the bottom surface of both members forms a flat surface. ing. By setting it as such a shape, the contact area with the heat generating part 11 can be taken large. Further, the heat radiating member 3 can be easily adhered to the heat generating portion 11. Therefore, high thermal conductivity / heat radiation effect can be obtained.

  The shape of the upper surface side of the heat radiating member main body is not particularly limited. For example, it is good also as the shape etc. which made the corner | angular part by the side of the upper surface (surface which contact | abuts with the surface panel 9 back) of the thermal radiation member main body 3b C-chamfering or R-chamfering.

  Also in the second embodiment, an alumina sintered body having excellent thermal conductivity and thermal emissivity is used as the heat radiating member. Therefore, it is not necessary to form a complicated shape such as forming a large number of heat radiation fins as in a normal heat sink.

  On the other hand, the shape of the upper surface side of the collar portion is preferably a planar shape so that it can be easily adhered to the inner surface of the back cover. For example, in the heat radiating member 3 shown in FIGS. By adopting such a shape, stable fixing can be performed when the flange 3 a is sandwiched between the heat generating portion 11 and the back cover 7.

  The thickness of the heat radiating member body is not particularly limited. However, it is preferable that the heat radiating member main body is thin so as not to impair the small, thin, and lightweight characteristics of the smart device. For example, the heat radiating member main body 3 b shown in FIGS. 2A to 2E is configured to be slightly thinner than the device main body 13. On the other hand, in order to exhibit thermal conductivity and thermal radiation, it is preferable that the heat radiating member body has a certain thickness. Considering the above, the thickness of the heat radiating member main body is more preferably 5 to 10 mm, and particularly preferably 7 to 9 mm.

  The collar portion is made thinner than the heat radiating member body. The specific thickness is not particularly limited. However, since the collar portion is disposed inside the back cover from the heat radiating member main body, it is preferable that it is thinner. On the other hand, the collar portion is a portion sandwiched between the back cover and the heat generating portion, and preferably has a certain thickness to ensure mechanical strength. Considering the above, the thickness of the collar portion is preferably 1 to 4 mm, and more preferably 2 to 3 mm.

  Similar to the first embodiment, the number of heat dissipating members is not limited to one and may be plural. By dividing the heat dissipating member into a plurality of parts, it is easy to arrange the heat dissipating member according to the shape of the device body and the position of the heat generating part. However, in the second embodiment, since it is necessary to form a flange on the heat dissipation member and to form an opening in the back cover, it is preferable to reduce the number of heat dissipation members because the structure can be simplified. . For example, in the smart device 1B shown in FIGS. 2A to 2C, only one heat radiating member 3 is arranged. Considering the above, the number of heat dissipating members is preferably 1 to 2, and more preferably 1.

  Also in the second embodiment, when a plurality of heat radiating members are arranged, it is not always necessary to equalize the thickness, shape, and size of the plurality of heat radiating members. That is, each heat radiating member may have a different thickness, shape, and size.

  The size (width, length) of the entire heat dissipating member including the collar is not particularly limited. However, the size of the entire heat radiating member is configured to be smaller than the size of the device body. For example, in the smart device 1B shown in FIGS. 2A to 2C, the heat radiating member 3 is configured such that the size of the collar portion 3a is smaller than the size of the device main body 13. With this configuration, the heat dissipation member 3 can be built in the device body 13.

  The width of the buttocks is not particularly limited. However, in order to be able to be securely locked to the back cover, a certain amount of width is required for the collar portion. On the other hand, in order to ensure the size of the heat radiating member main body, it is preferable not to widen the width of the collar portion too much. Considering the above, it is preferable that the flange portion protrudes 2 to 5 mm around the bottom surface of the heat radiating member body, and more preferably 2 to 4 mm.

  In addition, the collar part should just be a structure which can be pinched | interposed with the inner surface of a back cover, and a heat generating part, and it is always projecting along the four sides in the bottom face of the heat radiating member main body 3b like the heat radiating member 3 shown to FIG. It is not necessary to have a separate structure. For example, it is good also as a structure which protruded the collar part along two parallel sides in the bottom face of the thermal radiation member main body 3b of the structure shown to FIG. 2A-FIG. 2E.

  The size (width, length) of the heat radiating member body is not particularly limited. What is necessary is just to determine suitably considering the size of the whole heat radiating member, the width | variety of a collar part, heat conductivity, and heat dissipation. Considering the above, the size of the heat radiating member main body is preferably 20 to 50%, more preferably 20 to 40% with respect to the size of the device main body. Regarding the size, not only when one heat radiating member 3 as shown in FIGS. 2A to 2C is arranged, but also when a plurality of heat radiating members are arranged, the same configuration can be adopted.

[3-4] Back cover:
In 2nd Embodiment, the back cover of the device main body in which the opening part of the shape which can fit a heat radiating member main body was formed is provided. In the second embodiment, the back cover functions as a fixing member for the heat dissipation member. For example, as shown in FIGS. 2A to 2C, the bottom surface of the heat radiating member 3 (the heat radiating member main body 3 b and the flange portion 3 a) is in direct contact with the surface of the heat generating portion 11. On the other hand, the upper surface of the flange 3 a is in contact with the inner surface of the back cover 7. And the back cover 7 is fixing the heat radiating member 3 by pressing down the collar part 3a of the heat radiating member 3 with respect to the heat generating part 11. FIG. In other words, the flange portion 3 a is sandwiched between the back cover 7 and the heat generating portion 11.

  In the second embodiment, since the heat radiating member is fixed by the back cover having higher rigidity than that of the aluminum adhesive tape, the fixing can be more surely performed than in the first embodiment. Moreover, since the heat radiating member and the heat generating portion are brought into direct contact, it is preferable in terms of improving heat transfer and heat radiating properties as compared with the first embodiment in which a back cover is interposed between the heat radiating member and the heat generating portion.

  The opening is formed in a size that can fit the heat radiating member body and does not allow the eaves to pass through the opening. In other words, the heat dissipating member main body may be formed to be larger than the shape when viewed from the upper surface side and smaller than the shape when the collar portion is viewed from the upper surface side. From the viewpoint of securely fixing the heat radiating member so as not to move, the heat radiating member main body is formed in a shape complementary to the shape of the upper surface when viewed from above, and the gap between the opening and the heat radiating member main body is made as small as possible. It is preferable.

[4] Alumina sintered body:
In both the first embodiment and the second embodiment, the heat radiating member is composed of an alumina sintered body excellent in thermal conductivity, thermal emissivity, and electrical insulation. As the alumina sintered body, for example, ceramics for heat radiating members already disclosed by the present applicant can be suitably used (see JP 2012-503826 A). Therefore, in the present specification, the content of the above publication is cited, and only the outline and the form suitable for the present invention will be described below.

  The alumina sintered body preferably has a thermal conductivity of 30 to 60 W / m · K. If the thermal conductivity is 30 W / m · K or more, it is possible to quickly absorb heat from the heat generating part of the device body and dissipate it. On the other hand, by setting it to 60 W / m · K or less, it becomes easy to produce or obtain an alumina sintered body. In order to obtain the effect more reliably, the thermal conductivity is preferably 33 to 50 W / m · K, and preferably 36 to 45 W / m · K.

  The thermal conductivity means a value calculated from the density measured by the Archimedes method, the specific heat measured by the thermal conductivity measuring device based on the laser flash method, and the thermal diffusivity.

  The alumina sintered body preferably has a thermal emissivity of 0.93 to 0.99. By setting the thermal emissivity to 0.93 or more, it is possible to quickly convert the absorbed heat into infrared rays and dissipate it. On the other hand, by setting it to 0.99 or less, it becomes easy to produce or obtain an alumina sintered body. In order to acquire the said effect more reliably, it is preferable that thermal emissivity is 0.96-0.98.

  The said thermal emissivity shall mean the value measured with the measuring device (For example, brand name "HFT-40" <made by Anritsu Keiki Co., Ltd.>) based on a heating plate method.

  The alumina sintered body has an alumina content of 99.0% by mass or more, a silica content of 0.1% by mass or less, a crystal grain size of 1 to 10 μm, and crystal grains in an area of 30 × 20 μm. What is contained in the range of 20-65 is preferable. More preferably, the alumina content is 99.5% by mass or more, the crystal grain size is 1 to 5 μm, and the number of crystal grains is 30 to 55.

  Examples of the alumina sintered body as described above include alumina sintered bodies (1) to (6) shown in Table 1 below. Alumina sintered bodies (1) to (6) correspond to the ceramics for heat radiation members of Examples 1 to 6 of the publication. In FIG. 3, the figure of the electron micrograph which shows the crystal state of an alumina sintered compact (1) was shown. Such an alumina sintered body can be produced using α-alumina powder obtained by the Bayer method.

  The alumina sintered body has an alumina content of 99.5% by mass or more, a silica content of 0.1% by mass or less, a crystal grain size of 1 to 5 μm, and crystals in an area of 30 × 20 μm. Those containing 100 to 180 grains are also preferred. More preferably, the alumina content is 99.9% by mass or more, the crystal grain size is 1 to 3 μm, and the number of crystal grains is 100 to 150.

  Examples of the alumina sintered body as described above include alumina sintered bodies (7) shown in Table 1 below. The alumina sintered body (7) corresponds to the ceramic for heat radiation member of Example 8 of the above publication. In FIG. 4, the figure of the electron micrograph which shows the crystal state of an alumina sintered compact (7) was shown. Such an alumina sintered body can be produced using an alumina powder obtained by a sol-gel method.

  The crystal grain size and the number of crystals are values measured by scanning electron microscope observation (SEM). In addition, about the alumina sintered compact (7), 4 area | regions were extracted from the electron micrograph of FIG. 4, and the number of crystal grains was counted. As a result, the number of crystal grains was 128, 131, 131, and 129.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to the configurations of the following embodiments.

<Comparative Example 1>
The smart phone shown below was used as the smart device of Comparative Example 1.

As the smartphone, the model number “ISW11K” (manufactured by Kyocera Corporation) was used. This smartphone is equipped with a model number “MSM8655” (1.4 GHz, single core) of “Snapdragon” as a CPU and a version 2.3.5 of “Android” as an OS installed. Other specifications are shown below. “Android” is a trademark or registered trademark of Google, and “Snapdragon” is a trademark of Qualcomm.
Memory: RAM (1GB) / ROM (4GB)
Battery: 1220mAh
Size: Width 65mm x Length 128mm x Thickness 8.7mm
Weight: about 130g

<Example 1>
The smart device of Example 1 was obtained by attaching a heat dissipation member made of an alumina sintered body to the smart device of Comparative Example 1 with an aluminum adhesive tape. The specific structure is the same as that of the smart device 1A shown in FIGS. 1A to 1C.

  As the heat radiating members 2a, 2b, and 2c, those obtained by processing the alumina sintered body (1) shown in Table 1 into a flat plate having a width of 20 mm, a length of 40 mm, and a thickness of 5 mm were used. As the aluminum adhesive tape 4, an aluminum adhesive tape (commercially available) having an aluminum foil having a thickness of 0.05 mm as a tape base material was used.

  The ratio of the total size (area) of the three heat radiating members 2a, 2b, and 2c to the size (area) of the device body 12 was 28.8 area%. Moreover, the area of the part coat | covered with the aluminum adhesive tape 4 was 10% or less among the exposed areas of the thermal radiation member 2a, 2b, 2c.

<Example 2>
In the smart device of Comparative Example 1, an opening was formed in the back cover, and a heat dissipation member made of an alumina sintered body was fitted into the opening from the inside of the back cover was used as the smart device of Example 2. The specific structure is the same as that of the smart device 1B shown in FIGS. 2A to 2C.

  The shape of the heat radiating member was the same as that of the heat radiating member 3 shown in FIGS. As the heat radiating member 3, a material obtained by processing the alumina sintered body (1) shown in Table 1 into the following shape was used. The heat radiating member main body 3b was a flat plate having a thickness of 7 mm and a width of 40 mm and a length of 60 mm. The eaves part 3a has a thickness of 2 mm, and has a structure of protruding by 3 mm in width around the bottom surface of the heat radiating member main body 3b.

  The opening of the back cover had a rectangular shape with a width of 40 mm and a length of 60 mm. That is, the heat dissipation member body 3b has a shape that is complementary to the shape of the heat radiation member body 3b as viewed from above. And the part of the heat radiating member main body 3 b of the heat radiating member 3 is fitted into the opening 14 from the inside of the back cover 7, and the flange 3 a of the heat radiating member 3 is sandwiched between the heat generating part 11 of the front panel 9 and the back cover 7. And fixed.

[Evaluation]
After discharging the smartphone until the remaining battery level reached 20%, the operation was continued while charging and the CPU operation rate was 40 to 60% or 80 to 90%, and this was continued. Less than 10 minutes after that, when the charging operation is forcibly terminated due to a rise in the body temperature, “bad” (x), 10 minutes or more, when the charging operation is continued, “good (Δ)”, 20 minutes or more The case where the charging operation was continued was evaluated as “very good (◯)”.

  In the evaluation, the remaining battery level, the CPU operating rate, and the temperature of the device main body were values measured by version 3.7 of the battery management application “Battery Mix”. The temperature of the device body was the battery temperature measured by the application.

  As shown in Table 2, when the smart device of Comparative Example 1 continues the operation with a large load of the CPU operating rate of 40 to 60% while performing the charging operation, the main body temperature rises to 45 to 50 ° C. Was forcibly terminated.

  On the other hand, in the smart device of Example 1, the main body temperature is maintained at 35 to 42 ° C. even if an operation with a high CPU operating rate of 40 to 60% is continued while performing the charging operation, and the charging operation is forcibly terminated. It never happened. Similarly, even if an operation with a very high CPU operating rate of 80 to 90% is continued, the main body temperature is maintained at 40 to 45 ° C., and the charging operation is not forcibly terminated. That is, the smart device of Example 1 was superior in thermal conductivity and heat dissipation than the smart device of Comparative Example 1, and could effectively prevent forced termination due to heat.

  In addition, the smart device of Example 2 maintains the main body temperature at 33 to 40 ° C. and forcibly terminates the charging operation even if the operation with a high CPU operating rate of 40 to 60% is continued while performing the charging operation. It never happened. Similarly, even if an operation with an extremely high CPU operating rate of 80 to 90% was continued, the main body temperature was maintained at 38 to 43 ° C., and the charging operation was not forcibly terminated. That is, the smart device of Example 2 was more excellent in thermal conductivity and heat dissipation than the smart device of Example 1, and could more effectively prevent malfunction and forced termination due to heat.

1A, 1B: smart device, 2: heat radiating member, 2a, 2b, 2c: heat radiating member, 3: heat radiating member, 3a: collar, 3b: heat radiating member main body, 4: aluminum adhesive tape, 6, 7: back cover, 8, 9: Front panel, 10, 11: Heat generating part, 12, 13: Device body, 14: Opening part.

Claims (12)

  A heat radiating member kit for a smart device, comprising: a heat radiating member made of an alumina sintered body; and an aluminum adhesive tape for fixing the heat radiating member to a device body.   The heat radiating member kit according to claim 1, wherein the heat radiating member has a thermal conductivity of 30 to 60 W / m · K and a thermal emissivity of 0.93 to 0.99.   The alumina sintered body has an alumina content of 99.0% by mass or more, a silica content of 0.1% by mass or less, a crystal grain size of 1 to 10 μm, and crystal grains in an area of 30 × 20 μm. The heat radiating member kit according to claim 1, wherein the heat radiating member kit is contained in a range of 20 to 65 pieces.   The alumina sintered body has an alumina content of 99.5% by mass or more, a silica content of 0.1% by mass or less, a crystal grain size of 1 to 5 μm, and crystal grains in an area of 30 × 20 μm. The heat radiating member kit according to claim 1 or 2, wherein 100 to 180 are contained. A smart device formed using the heat dissipation member kit according to any one of claims 1 to 4,
The heat dissipating member is disposed at a position overlapping the heat generating portion of the device main body, and is fixed to the device main body by the aluminum adhesive tape so as to contact the outer surface of the back cover. Smart device.   The smart device according to claim 5, wherein the heat generating portion is a portion where at least one component selected from a group of a CPU and a battery is disposed.   The back surface of the device main body formed of an alumina sintered body and having a heat radiating member main body and a heat radiating member having a flange projecting around the bottom surface of the heat radiating member main body, and an opening having a shape capable of fitting the heat radiating member main body And a heat dissipating member kit for a smart device.   The heat radiating member kit according to claim 7, wherein the heat radiating member has a thermal conductivity of 30 to 60 W / m · K and a thermal emissivity of 0.93 to 0.99.   The alumina sintered body has an alumina content of 99.0% by mass or more, a silica content of 0.1% by mass or less, a crystal grain size of 1 to 10 μm, and crystal grains in an area of 30 × 20 μm. The heat dissipating member kit according to claim 7 or 8, comprising 20 to 65 in a range.   The alumina sintered body has an alumina content of 99.5% by mass or more, a silica content of 0.1% by mass or less, a crystal grain size of 1 to 5 μm, and crystal grains in an area of 30 × 20 μm. The heat radiating member kit according to claim 7 or 8, wherein 100 to 180 is contained. A smart device formed using the heat dissipating member kit according to any one of claims 7 to 10,
The heat dissipating member is disposed at a position overlapping the heat generating part of the device main body, the flange is disposed inside the back cover, and the heat dissipating member main body is fitted into the opening, A smart device characterized in that the flange is fixed to the device body so as to contact the inner surface of the back cover.   The smart device according to claim 11, wherein the heat generating portion is a portion where at least one component selected from a group of a CPU and a battery is disposed.

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