JP2010055642A - Electronic appliance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To radiate efficiently and suppress a formation of a heat spot in a case, even when using a heat generating member of a bigger heat generating value. <P>SOLUTION: An electronic appliance 100" includes a substrate 2 which has mounted a heat generating element 1, an operation unit 12 operated in order to input an information into a substrate, a heat dissipation plate 4 which radiates heat in a heat generating element, a supporting arrangement 5 which supports a heat dissipation plate, and an operation unit. It has the case 10 which accommodates the substrate, the heat dissipation plate and the supporting arrangement. The heat generating element is prepared in an opposite side with an operation unit about the substrate, The supporting arrangement is arranged between a second wall section 10b of the opposite side with a first wall section 10a of the case with which the operation unit is prepared and a heat dissipation plate, and forms an air layer between the heat dissipation plate and the second wall section. It prevents that the second wall section contacts the heat dissipation plate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic device in which a heating element such as an LSI is accommodated in a housing.

  In notebook computers, mobile phones, and other electronic devices, while thinning and miniaturization are progressing, the amount of heat generated from electronic components such as built-in LSIs tends to increase. Conventionally, a cooling method using a heat sink (heat radiating plate), a cooling fan, or the like has been adopted for such a heat generating component.

  The heat radiating plate is formed using a material having high thermal conductivity, and radiates heat by diffusing heat from the heat generating component. However, heat dissipation from the heatsink prevents the temperature of the electronic device casing, particularly the part that the user touches with the hand (for example, the part where the operation buttons are arranged) from rising and causing discomfort to the user. There is a need.

  For this reason, Patent Document 1 discloses a heat dissipation structure in which a heat dissipation plate and a vacuum heat insulating material are stacked between a heat generating component and a device case to suppress a temperature rise of the case while dissipating the heat generating component. Has been.

  Further, in Patent Document 2 and Patent Document 3, a heat conducting member, a heat radiating plate (Patent Document 3), and a heat insulating member are disposed so as to overlap each other between a heat generating component and a housing or an exterior cover. A heat dissipating structure is disclosed that prevents heat transfer to a portion of a housing or cover that contacts a human body while dissipating heat from a heat generating component.

  Patent Document 4 discloses a heat dissipation structure that dissipates heat by transmitting heat from a heat-generating component to a housing using a heat diffusion sheet. Further, in Patent Document 4, a heat-insulating layer by air is provided by disposing a frame-shaped support frame (spacer) between a portion of the heat diffusion sheet immediately below the heat generating member and the housing, There has been proposed a structure that prevents the temperature of the portion immediately below the heat-generating component from locally rising.

JP 2001-350546 A JP 2002-319652 A JP 2003-8956 A Japanese Patent Laid-Open No. 10-229287

  However, in the heat dissipating structures disclosed in Patent Documents 1, 2, and 3, basically, a heat insulating member 207 overlaid on the heat dissipating plate 204 and the heat conducting member 206 is provided in the casing 210 as shown in FIG. It is in contact. For this reason, when the amount of heat generated from the heat generating component 201 increases, the heat transmitted through the heat insulating member 207 is transmitted to the casing 210, and the temperature of the casing 210 increases. In particular, the center P of the region overlapping the heat generating component 201 when viewed from the direction in which the heat generating component 201, the heat radiating plate 204, the heat conducting member 206, and the heat insulating member 207 overlap in the casing 210 is significantly larger than the surrounding area. There is a high possibility that the heat spot will be heated.

  Further, according to the heat dissipation structure disclosed in Patent Document 4, by providing an air heat insulating layer between the thermal diffusion sheet and the casing, a local temperature rise is generated in a region overlapping the heat generating component in the casing. Can be prevented. However, there is a possibility that a local temperature rise may occur in a portion near the heat generating component (for example, a portion adjacent to the support frame and where the heat diffusion sheet is in direct contact with the housing) in the region where the air insulation layer is not provided.

  The present invention provides an electronic device having a heat dissipation structure that can efficiently dissipate heat even when a heat generating member having a larger heat generation amount is used, and that can suppress the formation of heat spots in the housing. One of the purposes.

  An electronic apparatus according to an aspect of the present invention supports a substrate on which a heating element is mounted, an operation unit that is operated to input information to the substrate, a radiator plate that radiates heat from the heating element, and the radiator plate. A support member, and a housing for housing the substrate, the heat radiating plate, and the support member, wherein the heating element is provided on a side opposite to the operation unit with respect to the substrate. The support member is disposed between the heat sink and the second wall portion on the opposite side of the first wall portion of the housing in which the operation portion is provided, and the heat sink and the second heat sink. An air layer is formed between the second wall portion and the heat radiating plate to prevent the second wall portion from contacting the heat radiating plate. The electronic device further includes a battery that is detachably attached to the casing, and the second wall portion is a part of a wall in which the casing stores the battery.

  According to this, since the heat diffused from the heat radiating plate becomes difficult to be transmitted to the second wall due to the heat insulating action of the air layer, a heat spot is formed on the second wall even when a heat generating member having a large heat generation amount is used. It can suppress forming.

  In addition, a heat insulating member may be disposed on the second wall portion side of the heat radiating plate, and an air layer may be formed between the heat insulating member and the second wall portion. The heat insulating action by the heat insulating member and the heat insulating action by the air layer are combined to suppress the formation of heat spots more effectively. In addition, when the thickness of the air layer is at least half the size of the heat insulating member, a sufficient heat insulating effect by the air layer can be obtained.

  Moreover, it is good to open an air layer with respect to spaces other than this air layer in a housing | casing. Thereby, the heat transmitted to the air layer from the heat radiating plate or the heat insulating member diffuses into the space in the housing, and the formation of heat spots can be more effectively suppressed.

  Further, the support member may be formed of a fiber material, a foam material, or a laminated material including a heat insulating material therein. Since these materials have low thermal conductivity, heat transfer to the second wall portion through the support member can be suppressed.

  Further, the support member may be arranged outside the arrangement area of the heat generating element (area overlapping the heat generating element) when viewed from the direction in which the heat generating element and the heat radiating plate overlap. Thereby, the heat transfer to the 2nd wall part via a support member can be suppressed more effectively. For example, a plurality of support members may be arranged apart from each other outside the heating element arrangement region, or the support members may be formed in a frame shape surrounding the heating element arrangement region.

  Further, the support member may be elastic, and the heat radiating plate and the heating element may be pressed against each other by an elastic force. Thereby, the thermal resistance between a heat generating body and a heat sink can be made small, and it can thermally radiate more efficiently.

  Moreover, you may make it the part which contacts a heat generating body among heat sinks protrude in the heat generating body side rather than the other part of this heat sink. Thereby, an electronic component different from the heat generating element can be disposed between the heat radiating plate and the substrate to which the heat generating element is attached, which is effective for downsizing of the electronic device. In addition, by giving elasticity to the heat sink and making the protruding part press-contact with the heat generator by elastic force, the heat resistance between the heat generator and the heat sink can be reduced and heat can be radiated more efficiently. Can do.

  Furthermore, you may arrange | position the heat spreader larger in size than a heat generating body between a heat generating body and a heat sink. Thereby, the amount of heat transfer in the in-plane direction of the heat sink can be increased, and heat can be efficiently radiated by the heat sink.

  In addition, the board | substrate with which the heat generating body was attached can also be used as a heat sink. As a result, a heat sink separate from the substrate can be eliminated, and the electronic device can be reduced in thickness, size, and weight.

According to the present invention, heat diffused from the heat radiating plate is hardly transmitted to the second wall portion of the casing due to the heat insulating action of the air layer. It can suppress that a heat spot is formed in the wall part.

It is sectional drawing which shows the structure inside the housing | casing of the mobile telephone which is Example 1 of this invention. It is sectional drawing which shows the effect at the time of giving elasticity to a support stand in Example 1. FIG. FIG. 3 is a plan perspective view showing an example of arrangement of support bases in Example 1. FIG. 6 is a plan perspective view showing another example of arrangement of support bases in Example 1. It is the schematic of the fiber type material used as a support stand in an Example. It is the schematic of the foam type material used as a support stand in an Example. It is the schematic of the laminated material used as a support stand in an Example. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 2 of this invention. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 3 of this invention. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 4 of this invention. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 5 of this invention. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 6 of this invention. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 7 of this invention. It is sectional drawing which shows the structure inside the housing | casing of the portable electronic device which is Example 8 of this invention. 1 is a schematic configuration diagram of a portable electronic device of Example 1. FIG. FIG. 10 is a schematic configuration diagram of a portable electronic device according to an eighth embodiment. FIG. 3 is a diagram showing an experimental example of Example 1. FIG. 3 is a diagram showing an experimental example of Example 1. FIG. 6 is a diagram showing an experimental example of Example 3. FIG. 6 is a diagram showing an experimental example of Example 3. It is a schematic block diagram of the portable electronic device which is Example 9 of this invention. It is sectional drawing which shows the internal structure of the conventional electronic device.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 12 shows a schematic configuration of a portable electronic device (electronic device) that is Embodiment 1 of the present invention. The portable electronic device 100 according to the present embodiment includes a first main body 30 and a second main body 40 attached to the first main body 30 so as to be openable and closable around the hinge 42.

  The first main body 30 is configured by housing the heating element 1, the substrate 2, and the heat radiating plate 4 in a housing 10 that is a resin case such as plastic. A battery 16 is detachably attached to the housing 10. In the first main body 30, the front wall portion of the housing 10, that is, the housing front wall 10 a that is the first wall portion, is provided with an operation portion 12 in which a keypad and other operation members are disposed. ing. The housing front wall 10a does not need to be a wall without an opening, and actually a plurality of openings for exposing the operation member are formed.

  In the second main body 40, a display 41 composed of a liquid crystal element or a self-luminous element is provided on the front wall portion of the housing which is a case made of a resin such as plastic or a metal such as aluminum. ing. A circuit (not shown) for driving the display 41 is built in the housing.

  The heating element 1 is represented by an arithmetic processing device such as an LSI or a CPU. However, in the present invention, electronic components other than the arithmetic processing unit are included in the heating element as long as they generate heat. The basic configuration of the mobile electronic device described above is the same in the embodiments described below.

  FIG. 1A shows an enlarged structure in the housing 10 constituting the first main body 30. In this figure, the housing front wall 10a is shown downward. The same applies to the following embodiments.

  The heating element 1 is mounted on a surface of the printed board (hereinafter simply referred to as a board) 2 on the housing front wall 10a side. The heating element 1 and the substrate 2 are disposed so as to be substantially parallel to the housing front wall 10, and the substrate 2 has a size in the in-plane direction that extends almost entirely within the housing 10. Although not shown, various electronic components other than the heating element 1 are also mounted on the substrate 2.

  The heat radiating plate 4 is disposed so as to be substantially parallel to the substrate 2 between the heating element 1 and the housing front wall 10a, and is in contact with the heating element 1. The heat radiating plate 4 dissipates heat by diffusing heat generated in the heat generating element 1, and cools the heat generating element 1. The heat radiating plate 4 is generally formed of a metal material having high thermal conductivity such as aluminum (thermal conductivity 200 to 300 W / m · K) or copper (thermal conductivity 300 to 400 W / m · K).

  However, if a graphite sheet (thermal conductivity 200 to 600 W / m · K) is used as the material of the heat sink 4, the weight can be reduced as compared with the case of using a metal material. Although not shown, the heat radiating plate 4 may have a fin shape or the like for increasing the heat radiating surface area.

  Screws 3 are attached to both left and right ends of the substrate 2, and these screws 3 are fastened and fixed in screw holes formed in the housing front wall 10 a. In this embodiment, the support 5 is disposed between the heat radiating plate 4 and the housing front wall 10a, whereby the air layer 6 having a predetermined thickness between the heat radiating plate 4 and the housing front wall 10a. Is forming. That is, in the present embodiment, the support base 5 (air layer 6), the heat radiating plate 4, the heating element 1 and the substrate 2 are arranged in this order in the housing 10 from the housing front wall 10a side.

  The support base 5 is sandwiched and fixed between the heat radiating plate 4 that receives the tightening force of the screws 3 via the substrate 2 and the heating element 1 and the housing front wall 10a. In other words, the support 5 has a function of securing the air layer 6 having a predetermined thickness by separating the heat sink 4 from the housing front wall 10a against the tightening force. In addition, you may fix the support stand 5 to the housing | casing front wall 10a or the heat sink 4 with an adhesion | attachment or a tape.

  The heat radiating plate 4 is formed to have substantially the same in-plane size with respect to the substrate 2 in order to increase the heat radiating efficiency as much as possible (however, small enough to avoid interference with the screw 3).

  Here, the plan view when the structure in the housing 10 is viewed from the support base 5 side in the direction in which the substrate 2, the heating element 1 and the heat radiating plate 4 overlap (viewed from the direction indicated by G in FIG. 1A). 2) is shown in FIG. In FIG. 2, 1 ′ is a region that overlaps the heating element 1 when viewed from the G direction between the housing front wall 10 a and the heat radiating plate 4, that is, when the heat radiating plate 4 is seen through from the G direction. The area | region where the body 1 exists is shown. Hereinafter, this region 1 'is referred to as a heating element arrangement region.

  And the support stand 5 is arrange | positioned outside the heat generating body arrangement | positioning area | region 1 '. In the present embodiment, there are two support bases 5 arranged apart from each other with the region 1 'outside the heating element arrangement region 1'. Each support base 5 has a cubic shape or a rectangular parallelepiped shape (including a plate shape). In the present embodiment, the case where two support bases 5 are provided will be described. However, in the present invention, the number of support bases is not limited to this, and three or more support bases are separated from each other outside the heating element arrangement region. May be arranged.

  In addition, as shown in FIG. 3, the support base 5 may be formed in a rectangular frame shape and disposed outside the heating element arrangement region 1 ′. That is, you may arrange | position the support stand 5 so that the heat generating body arrangement | positioning area | region 1 'may be enclosed.

  The shape and arrangement of the support base 5 shown in FIGS. 2 and 3 are merely examples, and the shape and arrangement of the support base in the present invention are the air layer 6 between the radiator plate 4 and the housing front wall 10a. Anything can be used as long as it can be secured. However, by disposing the support base 5 outside the heating element arrangement region 1 ′ as described above, it is difficult for the heat transferred from the heating element 1 to the heat radiating plate 4 to be transmitted to the heating element arrangement region 1 ′ via the support table 5. Can be.

  Furthermore, the support 5 is formed of a generally used material having low thermal conductivity, for example, a fiber-based material shown in FIG. 4A, a foam-based material shown in FIG. 4B, or a laminated material shown in FIG. 4C. An example of the fiber material is glass wool (thermal conductivity 0.034 W / m · K). Examples of the foam material include extruded polystyrene foam (thermal conductivity 0.038 W / m · K) and foamed polyethylene (thermal conductivity 0.035 W / m · K). Furthermore, as a laminated material, for example, as shown in FIG. 4C, there is a material in which a general heat insulating material 5a is sandwiched between elastic materials 5b such as urethane.

  Thus, it is preferable to form the support base 5 using a material having a lower thermal conductivity than plastic or metal. Thereby, it is possible to make it difficult for the heat transmitted from the heating element 1 to the heat radiating plate 4 to be transmitted to the housing front wall 10 a via the support 5.

  As shown in FIG. 1B by the dotted arrow J, the support 5 is formed by using a laminated material or other elastic material in which a heat insulating material is sandwiched between elastic materials shown in FIG. 4C. In addition, the heat radiating plate 4 and the heating element 1 can be pressed more strongly by the elastic force of the elastic member. Thereby, the thermal resistance to the heat sink 4 from the heat generating body 1 can be decreased, and the cooling effect of the heat generating body 1 by the heat sink 4 can be heightened.

  The air forming the air layer 6 has a heat conductivity of 0.026 W / m · K at 60 to 90 ° C. and a heat of not more than a general heat insulating member (heat conductivity of 0.026 W / m · K or more). Has conductivity. When a heat insulating member is disposed between the heat sink and the housing as in the prior art and the heat insulating member is brought into contact with the heating element arrangement region described above, the heat that could not be blocked by the heat insulating member passes through the heat insulating member. The heat spot is transmitted directly to the casing, and a heat spot having a very high temperature is formed in the heating element arrangement region in the casing as compared with the surrounding area. However, as in the present embodiment, the air layer 6 is formed between the heat sink 4 and the front wall 10a of the housing, so that the heat is applied to the housing as compared with the case where the heat insulating member is placed in contact with the housing. Is less likely to be transmitted and a higher thermal insulation effect is obtained. Therefore, formation of a heat spot in the housing 10 can be avoided.

  In addition, the portable electronic device 100 can be reduced in weight by providing the air layer 6 with the support base 5 having a small size instead of the heat insulating member having the same size as the heat sink 4.

  Further, the heat radiating plate 4 is not in contact with the housing 10, and the air layer 6 (the entire outer periphery thereof) is opened to a space other than the air layer 6 in the housing 10. For this reason, the heat transmitted from the heat radiating plate 4 to the air layer 6 is diffused in a space other than the air layer 6 in the housing 10. Thereby, formation of the heat spot in the housing front wall 10a can be avoided more effectively.

  Here, in FIGS. 14A and 14B and FIGS. 15A and 15B, when the air layer is formed between the heat radiating plate and the housing by the support base, the arrangement of the support base is shown. The contents of the experiment and the results for examining the relationship between the shape and the temperature of the housing are shown.

  In this experiment, as shown in FIG. 14 (A), a support formed of a fiber-based material (0.034 W / m · K) in order from the housing 310 (corresponding to the housing front wall 10a in FIG. 1A). A base 305, a heat radiating plate 304 made of a copper plate (385 W / m · K), a 10 mm square rectangular heating element 301 and a substrate 302 were arranged.

  In the pattern 1 shown in FIG. 14B, in the same plan view as in FIGS. 2 and 3, a support base having a rectangular shape of 12 mm square is placed so as to overlap the heating element placement region 301 ′, and points A to F The temperature of the casing 310 was measured. Point A is the center of the heating element arrangement region 301 ′, point B is a point about 14 mm away from the point A in the diagonal direction of the support base, and points C and D are points 10 mm and 20 mm away from the point B in the same diagonal direction. It is. Further, point E is a point 10 mm away from point A in a direction parallel to two opposing sides of the support base, and point F is a point further 10 mm away from point E in the same parallel direction.

  The pattern 1 is equivalent to the case where a heat insulating member is disposed between the heat sink and the housing, and the heat insulating member is brought into contact with the housing including the point A.

  In the pattern 2, four support bases having a rectangular shape of 6 mm square are arranged at the corners of a 20 mm square rectangle surrounding the area 301 ′ outside the heating element arrangement area 301 ′, and the housings at points A to F are arranged. The temperature of the body 310 was measured. The positions of points A to F are the same as in pattern 1.

  In Pattern 3, a support base having a rectangular frame shape of 20 mm square was placed outside the heating element placement region 301 ′ so as to surround the region 301 ′, and the temperature of the casing 310 at points A to F was measured. . The positions of points A to F are the same as in pattern 1. In Patterns 1 to 3, the thickness of the support base and the air layer (the height in the overlapping direction of the support base 305, the heat sink 304, the heating element 301, and the substrate 302) was the same.

  FIG. 15A shows the temperature (° C.) from the point A to the point F in the patterns 1 to 3 measured at an ambient temperature of 35 ° C. Further, FIG. 15A shows the temperature (° C.) of the heating element 301, the heat generation amount (power consumption) (W) of the heating element 301, and the thermal resistance value (° C./W) between the heating element 301 and the point A. It also shows. Further, FIG. 15B shows the temperature of the heating element 301 and the temperature change from point A to point C in patterns 1 to 3.

  In patterns 2 and 3, the casing temperature at point A was lower by about 5 ° C. than pattern 1. Further, the temperature at point B in patterns 2 and 3 was higher than that at point B in pattern 1 because it was in contact with the support base 305. Similarly, the temperature at point E in pattern 3 was higher than that at point B in pattern 1 because it was in contact with the support 305. However, the temperatures of the points B in the patterns 2 and 3 and the points E in the pattern 3 were lower than the temperatures of the points A in the patterns 2 and 3.

  The thermal resistance value between the heating element 301 and the point A was about 1.56 times higher in pattern 2 than pattern 1 and about 1.73 times higher in pattern 3 than pattern 1.

  As can be seen from the experimental results, the temperature of the position of contact with the support base in the case becomes higher by adopting the method of arranging the support bases of patterns 2 and 3, compared with the case where the contact is not in contact with the pattern 1. The temperature at point A, which has been a heat spot, decreases, and the heat spot can be eliminated. That is, the formation of a heat spot can be avoided in a wide range including the point A to the point F, and it is possible to prevent the user who touched the heat spot from feeling uncomfortable as in the case of the pattern 1.

  FIG. 5 shows a structure in the housing 10 constituting the first main body portion in the portable electronic device that is Embodiment 2 of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is omitted.

  In the present embodiment, the portion 4a 'of the heat radiating plate 4' that overlaps the heating element 1 has a shape protruding from the peripheral portion (other portion) 4b 'on the side opposite to the substrate 2 side. Specifically, the portion of the heat radiating plate 4 ′ that contacts the heating element 1 has a convex shape, and the opposite side has a concave shape.

  By forming the heat radiating plate 4 ′ in such a shape, when the heat radiating plate 4 ′ is formed of an elastic material, the heat radiating plate 4 ′ is caused by the elastic force K generated in the direction of the substrate 2. The adhesion between the protruding portion 4a 'and the heating element 1 can be improved. Thereby, the thermal resistance from the heat generating body 1 to the heat sink 4 'can be reduced, and the heat generating body 1 can be cooled more efficiently.

  Further, in the present embodiment, a space having a larger thickness than that of the first embodiment can be formed between the peripheral portion 4b ′ and the substrate 2 in the heat radiating plate 4 ′. Then, using this space, another large electronic component (such as an IC) 20 can be mounted on the surface of the substrate 2 on the side of the heat radiating plate 4 ′ (mounting surface of the heating element 1). Thereby, for example, the housing 10 (that is, the portable electronic device) can be made thinner and smaller than the case where the electronic component 20 is mounted on the surface of the substrate 2 opposite to the heat radiating plate 4 ′. .

  FIG. 6 shows a structure inside the housing 10 constituting the first main body portion in the portable electronic device that is Embodiment 3 of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is omitted.

  In this embodiment, a plate-shaped heat insulating member (heat insulating plate) 7 having the same size in the in-plane direction as the heat radiating plate 4 is brought into contact with the surface of the heat radiating plate 4 on the housing front wall 10a side. Between the housing front wall 10a, the support base 5 is disposed to provide the air layer 6. That is, in this embodiment, the support base 5 (air layer 6), the heat insulating member 7, the heat radiating plate 4, the heating element 1 and the substrate 2 are arranged in this order in the housing 10 from the housing front wall 10a side. The heat insulating member 8 and the air layer 6 form a heat insulating layer 8 between the heat sink 4 and the housing front wall 10a. This embodiment is particularly effective when the heat generation amount of the heating element 1 is larger than that of the heating element of the first embodiment.

  As the heat insulating member 7, a general heat insulating material having a thermal expansion coefficient (0.026 W / m · K or more) equal to or higher than that of the air of the air layer 6 (0.024 to 0.026 W / m · K). For example, foamed urethane or silicon foam is used. Also in the case of the present embodiment, a higher heat insulating effect can be obtained as compared with the case where the heat insulating member is brought into contact with the housing, and the formation of heat spots in the housing can be avoided. That is, even when a general heat insulating member is used, since a high heat insulating effect is obtained by the air layer 6, it is possible to suppress the formation of heat spots.

  Here, when the heat insulating member is brought into contact with the housing as in the conventional case, it is considered that the formation of the heat spot can be avoided also by increasing the thickness of the heat insulating member. However, if an air layer is provided as in the present embodiment, the thickness of the air layer necessary to avoid the formation of the heat spot may be smaller than the increase in thickness of the heat insulating member. For this reason, by providing an air layer, compared with the case where the thickness of a heat insulation member is increased, the thickness from the board | substrate 2 to the housing | casing front wall 10a can be made thin. Therefore, the housing 10 (that is, the portable electronic device) can be made compact while avoiding the formation of a heat spot on the housing front wall 10a.

  Further, the heat radiating plate 4 and the heat insulating member 7 are not in contact with the housing 10, and the air layer 6 is opened to a space other than the air layer 6 in the housing 10. For this reason, the heat transmitted from the heat insulating member 7 to the air layer 6 is diffused in the air layer 6 or a space other than the air layer 6 in the housing 10 to more effectively form the heat spot on the housing front wall 10a. Can be avoided.

  Here, FIG. 16 shows the results of an experiment conducted to compare the temperature of the housing when the heat insulating member is made thick and in contact with the housing (when no air layer is provided) and when the air layer is provided. Shown in (B).

  FIG. 16A shows an experimental apparatus in which an air layer 406 is provided between the heat insulating member 407 and the housing front wall 410a. In the case where the air layer 406 was not provided, an experimental apparatus was used in which all the air layer 406 was also a heat insulating member 407. As shown in FIG. 16B, the thickness of the heat insulating member 407 when the air layer 406 is not provided is 1.5 mm, and the thickness of the heat insulating member 407 and the air layer 406 when the air layer 406 is provided is They are 1.0 mm and 0.5 mm, respectively. The casing 410 is 110 × 260 × 14 mm in outer size and has a wall portion thickness of 1 mm. The heating element 401 has a heating value of 3.5 W, a 50 × 100 mm copper plate (385 W / m · K) as the heat dissipation plate 404, and a thermal insulation member 407 with a thermal expansion coefficient of 0.026 W / m · K. Using.

  FIG. 16B shows the temperatures of the heating elements 401, the heat dissipation plate 404, the heat insulating member 407, and the centers I and H of the heating element arrangement regions on the inner and outer surfaces of the casing 410 (the casing front wall 410a) in both cases. As shown.

  As can be seen from FIG. 16B, compared to the case where the heat insulating member is thickened to 1.5 mm without providing an air layer, the heat insulating member is 1.0 mm and the air layer 406 is 0. In the case of 5 mm, the temperature of the outer surface of the casing was 1.2 ° C. lower. Thereby, the heat insulation effect superior to the heat insulation member of an air layer, ie, the avoidance effect of heat spot formation, could be confirmed. Furthermore, by setting the thickness of the air layer 6 (support base 5) to more than half of the thickness of the heat insulating member 7, the temperature of the outer surface of the housing is lowered as compared with the case where the heat insulating member has the same thickness. It was found to have an effect.

  Further, in the case where the air layer is not provided, it was speculated that the heat insulating member needs to be thicker than 1.5 mm in order to reduce the temperature of the outer surface of the housing to the same level as when the air layer 406 was provided. .

  FIG. 17 shows the results of an experiment conducted to compare the temperature of the housing in the case where an air layer is not provided and the case where an air layer is provided using a heat insulating member having the same thickness. In this experiment, the thickness of the heat insulating member was 1.0 mm, the heat generation amount of the heating element was 5 W, and a graphite sheet (240 W / m · K) was used as the heat radiating plate. In this experiment, a heat insulating member having a thermal expansion coefficient lower than that of air (0.005 W / m · K) was used. The other experimental conditions are the same as those in the experiments of FIGS.

  As can be seen from FIG. 17, the temperature on the outer surface of the casing was lower by 3.6 ° C. when the air layer was provided than when the air layer was not provided. Thus, it was found that by providing the air layer, the temperature of the housing can be lowered (the formation of a heat spot can be avoided more reliably) than in the case where the air layer is not provided.

  In the present embodiment, the case where the heat insulating member 7 and the support base 5 are configured as separate members has been described. However, a part of the heat insulating member 7 is formed in a shape protruding toward the housing front wall 10a and supported. You may make it use as a stand. In this case, a plate-like portion extending along the heat radiating plate of the heat insulating member corresponds to the “heat insulating member” according to claim 1, and the support trapezoidal portion corresponds to the “support base”. This is the same in other embodiments using a heat insulating member to be described later.

  FIG. 7 shows a structure in the housing 10 constituting the first main body portion in the portable electronic device that is Embodiment 4 of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the description is omitted.

  In the present embodiment, heat insulation is performed only on a region of the surface of the heat radiating plate 4 on the housing front wall 10a side in the first embodiment that substantially overlaps the heat generating member 1 when viewed from the direction in which the heat generating member 1 and the heat radiating plate 4 overlap. This corresponds to the member 7 '. The heat insulating member 7 ′ has a slightly larger in-plane size than the heating element 1.

  An air layer 6 is formed in a region of the heat radiating plate 4 where the heat insulating member 7 ′ does not overlap, and between the heat insulating member 7 ′ and the housing front wall 10 a. This embodiment is also particularly effective when the heat generation amount of the heating element 1 is larger than that of the first embodiment.

  As in the first embodiment, the air layer 6 is open to a space other than the air layer 6 in the housing 10. The support base 5 is disposed between a region of the heat radiating plate 4 where the heat insulating member 7 ′ does not overlap and the housing front wall 10 a.

  According to the present embodiment, it is possible to avoid the formation of heat spots on the front wall 10a of the housing due to the high heat insulating effect of the heat insulating member 7 'provided in the region substantially overlapping the heating element 1 and the air layer 6. it can. Moreover, it is possible to reduce the weight of the portable electronic device as compared with the case where the size of the heat insulating member 7 'is substantially the same as that of the heat sink 4 as in the second embodiment.

  FIG. 8 shows a structure inside the casing 10 constituting the first main body portion in the portable electronic device that is Embodiment 5 of the present invention. In the present embodiment, the same components as those in the third embodiment are denoted by the same reference numerals as those in the third embodiment, and the description is omitted.

  In the present embodiment, in the configuration of the third embodiment, as in the second embodiment, the portion 4a ′ of the heat radiating plate 4 ′ that overlaps the heating element 1 is placed on the front wall of the housing rather than the surrounding portion (other portion) 4b ′. It has a shape that protrudes to the opposite side to the 10a side. When the heat radiating plate 4 'is formed of an elastic material, the adhesion between the protruding portion 4a' and the heat generating element 1 is enhanced by the elastic force, and the heat generating element 1 is connected to the heat radiating plate 4 '. Thermal resistance can be reduced. Therefore, the heating element 1 can be cooled more efficiently.

  Also in this embodiment, a space having a thickness larger than that in the first embodiment can be formed between the peripheral portion 4b 'of the heat radiating plate 4' and the substrate 2, so that this space is utilized. Then, another large electronic component (IC or the like) 20 can be mounted on the surface of the substrate 2 on the side of the heat radiating plate 4 ′ (mounting surface of the heating element 1). Thereby, for example, the housing 10 (that is, the portable electronic device) can be made thinner and smaller than the case where the electronic component 20 is mounted on the surface of the substrate 2 opposite to the heat radiating plate 4 ′. .

  FIG. 9 shows a structure inside the casing 10 constituting the first main body portion in the portable electronic device that is Embodiment 6 of the present invention. In the present embodiment, the same components as those in the fifth embodiment are denoted by the same reference numerals as those in the fifth embodiment, and the description is omitted.

  In the present embodiment, in the surface of the heat radiating plate 4 ′ on the side of the housing front wall 10 a, the region on the opposite side of the protruding portion 4 a ′ that contacts (overlaps) the heating element 1 is slightly larger than the heating element 1. A heat insulating member 7 ″ having a directional size is provided.

  Thus, in addition to the effects described in the fifth embodiment, the high heat insulating effect of the heat insulating member 7 ″ provided in the region of the heat radiating plate 4 ′ substantially overlapping the heating element 1 and the air layer 6 allows the housing front wall 10a to It is possible to more reliably avoid the formation of heat spots in the heating element arrangement region (see FIGS. 2 and 3). Moreover, the size of the heat insulating member 7 ″ is substantially the same as that of the heat radiating plate 4 ′ as in the fourth embodiment. Compared to the case of the same size, the portable electronic device can be reduced in weight.

  FIG. 10 shows a structure inside the housing 10 constituting the first main body portion in the portable electronic device that is the seventh embodiment of the present invention. In the present embodiment, the same reference numerals as those in the third embodiment are assigned to components common to the third embodiment, and the description is omitted.

  In the present embodiment, in addition to the configuration of the third embodiment, a heat spreader 9 having a larger in-plane direction size than the heat generator 1 is disposed between the heat generator 1 and the heat radiating plate 4. The heat spreader 9 is made of a metal having high thermal conductivity, and transfers heat received from the heating element 1 in the in-plane direction with high thermal conductivity. For this reason, the heat from the heat generating body 1 can be transmitted to the heat radiating plate 4 in a larger area than the case where the heat generating body 1 is brought into direct contact with the heat radiating plate 4. Therefore, the amount of heat transfer in the in-plane direction of the heat sink 4 can be increased, and the heat sink 4 can efficiently dissipate heat.

  Further, since the heat spreader 9 is added, the heat conduction path from the heating element 1 to the housing front wall 10a becomes longer than that in the third embodiment, so that the heating element arrangement region 1 ′ ( The temperature in FIGS. 2 and 3) can be further reduced.

  This embodiment is particularly effective when the heating element 1 is small (when the contact area with the radiator plate 4 is small) or when the radiator plate 4 having a low thermal conductivity in the thickness direction, such as a graphite sheet, is used. It is.

  FIG. 14 shows a schematic configuration of a portable electronic device 100 ′ that is Embodiment 8 of the present invention. In the present embodiment, the same components as those of the portable electronic device 100 described in the first embodiment (FIG. 12) are denoted by the same reference numerals as in the first embodiment, and the description is omitted.

  In the present embodiment, the radiator plate 4 different from the substrate 2 described in the first embodiment is not disposed in the housing 10 constituting the first main body 30, and the substrate 2 ′ is made of aluminum nitride. The substrate 2 ′ itself functions as a heat radiating plate by manufacturing it with a material having high thermal conductivity or adopting a structure suitable for heat radiating.

  FIG. 11 shows an enlarged structure inside the housing 10. In the figure, the substrate 2 'is fixed to the front wall 10a of the housing with screws 3 at both left and right ends. The heating element 1 is mounted on the surface of the substrate 2 'opposite to the housing front wall 10a.

  A support base 5 is disposed between the substrate 2 'and the housing front wall 10a, whereby an air layer 6 having a predetermined thickness is formed between the substrate 2' and the housing front wall 10a. Has been. That is, in the present embodiment, the support 5 (air layer 6), the substrate 2, and the heating element 1 are arranged in the housing 10 in this order from the housing front wall 10a side.

  Also in this embodiment, the support 5 is sandwiched and fixed between the board 2 'receiving the tightening force by the screw 3 and the front wall 10a of the casing, and the board 2' is held against the tightening force. It has a function of securing an air layer 6 having a predetermined thickness apart from the front wall 10a. The support 5 may be fixed to the housing front wall 10a or the substrate 2 'by adhesion or tape.

  When the support base 5 is viewed from the support base 5 side in the direction in which the heat generator 1 and the substrate 2 ′ overlap, indicated by G in FIG. 11, the support base 5 is located outside the heat generator arrangement region described in the first embodiment. Is arranged. Specifically, for example, the support 5 having a shape as shown in FIGS. 2 and 3 is arranged outside the heating element arrangement region 1 ′ shown in FIG.

  As described in the first embodiment, the support 5 may be formed of a fiber material (FIG. 4A), a foam material (FIG. 4B), or a laminated material (FIG. 4C). Thereby, it is possible to make it difficult for the heat transmitted from the heating element 1 to the substrate 2 ′ to be transmitted to the housing front wall 10 a via the support 5.

  Also in the present embodiment, the heat insulating member disposed between the substrate 2 ′ and the housing front wall 10 a is formed by forming the air layer 6 between the substrate 2 ′ and the housing front wall 10 a. Compared to the case where the front wall 10a is brought into contact with the front wall 10a, heat is less likely to be transmitted to the housing 10. Therefore, it is possible to avoid the formation of a heat spot on the housing front wall 10a.

  In addition, the portable electronic device 100 ′ can be reduced in weight by providing the air layer 6 with the support base 5 having a small size instead of the heat insulating member having the same size as the substrate 2 ′.

  Further, the substrate 2 ′ is not in contact with the housing 10, and the air layer 6 is open to a space other than the air layer 6 in the housing 10. Thereby, the heat transmitted from the substrate 2 ′ to the air in the air layer 6 can be diffused into the space in the housing 10, and the formation of a heat spot can be avoided more effectively.

  Furthermore, in this embodiment, since the substrate 2 'functions as a heat dissipation plate, a heat dissipation plate different from the substrate 2' is not required, which is effective for reducing the thickness, size and weight of the portable electronic device 100 '. is there.

  18 shows a schematic configuration of a portable electronic device 100 ″ that is Embodiment 9 of the present invention. In this embodiment, the same components as those of the portable electronic device 100 described in Embodiment 1 (FIG. 12). Here, the same reference numerals as those in the first embodiment are attached and the description is omitted.

  In the first embodiment, a heat spot is not formed on the wall portion (housing front wall 10a) on the side where the operation unit 12 is provided in the first main body 30 (housing 10) due to the heat generated in the heating element 1. The configuration for making this has been described.

  On the other hand, in this embodiment, heat spots are prevented from being formed on the housing rear wall 10b, which is the wall portion of the housing 10 on the side where the battery 16 is mounted, due to the heat generated in the heating element 1. Specifically, the support base 5 (air layer 6), the heat radiating plate 4, the heating element 1 and the substrate 2 are arranged in this order in the housing 10 from the housing back surface 10b side.

  When a heat spot is formed on the rear wall 10b of the casing, the battery 16 is heated, and the temperature of a cover (a part of the casing) that covers the battery 16 rises. Since the cover portion is often touched by the hand when the user holds the portable electronic device 100 ″, the user may feel uncomfortable if the temperature of this portion is high. By avoiding the formation of a heat spot on the housing rear wall 10b, the temperature rise of the battery 16 and the cover covering the battery 16 can be suppressed.

  As described above, according to each of the above-described embodiments, heat is hardly transmitted to the first wall portion of the housing by the heat insulating action of the air layer. Therefore, even when a heat generating member having a large heat generation amount is used, the first It is possible to suppress the formation of heat spots at the wall portion.

  Although the preferred embodiments of the present invention have been described so far, the present invention is not limited to these embodiments, and various modifications and changes can be made. For example, the materials of the heat sink, the heat insulating member, and the support base are not limited to those described in the above embodiments. The present invention can be widely applied to electronic devices such as a mobile phone, a notebook personal computer (PC), and a digital camera.

INDUSTRIAL APPLICABILITY The present invention is useful as a cooling structure for a heating element in an electronic device such as a mobile phone, a notebook personal computer, and a digital camera, and is particularly suitable for cooling while avoiding the formation of a heat spot on a housing. ing.

1,401 Heating element 1 'Heating element arrangement area 2,402 Substrate 3,403 Screw 4,4', 404 Radiation plate 5,5 ', 5 ", 405 Support base 6,406 Air layer 7,407 Thermal insulation member 10, 410 housing 10a, 410a housing front wall 100, 100 ', 100 "portable electronic device

Claims (13)

A substrate mounted with a heating element;
An operation unit operated to input information to the substrate;
A heat radiating plate for radiating heat from the heating element;
A support member for supporting the heat sink;
The operation unit is provided, and a housing that houses the substrate, the heat dissipation plate, and the support member;
Have
The heating element is provided on the opposite side of the operation unit with respect to the substrate,
The support member is disposed between the heat sink and the second wall portion opposite to the first wall portion of the casing in which the operation portion is provided, and the heat sink and the second wall. An electronic device is characterized in that an air layer is formed between the second wall portion and the heat radiating plate.   The heat insulating member is disposed on the second wall portion side of the heat radiating plate, and the air layer is formed between the heat insulating member and the second wall portion. The electronic device described.   The electronic device according to claim 2, wherein the air layer has a thickness that is half or more of a thickness of the heat insulating member.   The electronic device according to claim 1, wherein the air layer is open to a space other than the air layer in the housing.   3. The electronic device according to claim 1, wherein a portion of the heat radiating plate that contacts the heat generator protrudes toward the heat generator from other portions of the heat radiating plate.   6. The electronic apparatus according to claim 5, wherein an electronic component different from the heating element is disposed between the other part and the substrate on which the heating element is attached.   The electronic apparatus according to claim 5, wherein the heat radiating plate has elasticity, and a portion protruding toward the heat generating element by an elastic force is pressed against the heat generating element.   The electronic device according to claim 1, wherein the support member is formed of a fiber material, a foam material, or a laminated material that includes a heat insulating material therein.   3. The electronic apparatus according to claim 1, wherein the support member is disposed outside an arrangement region of the heat generating element when viewed from a direction in which the heat generating element and the heat radiating plate overlap each other.   The electronic device according to claim 1, wherein the support member has elasticity and presses the heat radiating plate and the heating element by elastic force.   The electronic apparatus according to claim 1, wherein a heat spreader having a size larger than that of the heat generating element is disposed between the heat generating element and the heat radiating plate.   The electronic apparatus according to claim 1, wherein the heat radiating plate is a substrate on which the heating element is attached. A battery that is detachably attached to the housing;
3. The electronic device according to claim 1, wherein the second wall portion is a part of a wall in which the housing houses the battery. 4.