Patent ID: 12250792

DETAILED DESCRIPTION

Hereinafter, one or more embodiments of an electronic apparatus and a method of manufacturing the same according to one or more embodiments of the present invention will be described in detail with reference to the drawings. Note that, the present invention is not limited to these embodiments.

FIG.1is a schematic plan view of an electronic apparatus10according to one or more embodiments as viewed from above. As illustrated inFIG.1, the electronic apparatus10is a clamshell-shaped laptop PC in which a display chassis12and a chassis14are relatively and rotatably connected by a hinge16, and is a so-called mobile workstation. The electronic apparatus according to the present invention may be, for example, a desktop PC, a tablet PC, a portable phone, a smartphone, a game machine, or the like, other than a laptop PC.

The display chassis12is a thin flat box. A display18is mounted on the display chassis12. The display18is adapted to, for example, an organic EL (OLED: Organic Light Emitting Diode) or a liquid crystal.

Hereinafter, the chassis14and each element mounted on the chassis14will be described such that a space between the chassis12and14is set as being open as illustrated inFIG.1, a posture for visually recognizing the display18is set as a reference, a front side is set as a front, a rear side is set as a rear, a width direction is set as left and right, and a height direction (a thickness direction of chassis14) is set as top and bottom.

The chassis14is a thin flat box. The chassis14is adapted to a cover member14A, which forms a top surface and four peripheral side surfaces, and a cover member14B, which forms a bottom surface. The top cover member14A has a substantially bathtub shape in which a bottom surface is open. The bottom cover member14B has a substantially flat plate shape and serves as a lid that closes the bottom surface opening of the cover member14A. The cover members14A and14B are overlapped in the thickness direction and are connected to each other in an attachable and detachable manner. A keyboard20and a touch pad21are provided on the top surface of the chassis14. A rear end part of the chassis14is connected to the display chassis12by using the hinge16.

FIG.2is a plan view schematically illustrating an internal structure of the chassis14and is a schematic plan cross-sectional view of the chassis14cut slightly below the keyboard20.

As illustrated inFIG.2, a cooling module22, a motherboard24, a sub-board25, and a battery device26are provided inside the chassis14. Various electronic components, mechanical components, and the like are further provided inside the chassis14.

The motherboard24is a main board of the electronic apparatus10. The motherboard24is disposed closer to the rear of the chassis14and extends along the horizontal direction. The motherboard24is a printed substrate on which various electronic components such as a communication module, a memory, and a connection terminal are mounted in addition to a central processing unit (CPU)30. The motherboard24is disposed under the keyboard20and is screwed to a back surface of the keyboard20and an inner surface of the cover member14A. A top surface of the motherboard24is an attaching surface for the cover member14A, and a bottom surface is a mounting surface for the CPU30and the like. The CPU30is disposed substantially at the center of the left and right sides of the mounting surface of the motherboard24. The CPU30performs computing related to primary control or processing of the electronic apparatus10.

The sub-board25is an expansion card having a smaller outer shape than that of the motherboard24. The sub-board25is a printed substrate on which various electronic components such as a graphics processing unit (GPU)31or a power component32are mounted. The sub-board25is laminated in the vicinity of a right end of the mounting surface of the motherboard24(seeFIG.2), and the GPU31is mounted substantially in the center of the sub-board25. The sub-board25is connected to a connector mounted on the motherboard24, thereby the sub-board25is electrically connected to the motherboard24. A top surface of the sub-board25is an attaching surface with respect to the mounting surface of the motherboard24, and a bottom surface is a mounting surface25a(seeFIG.5) for the GPU31and the like. The GPU31performs computing necessary for image depiction such as 3D graphics. The reference numeral31ainFIG.5is a package substrate on which the GPU (die)31is mounted.

The battery device26is a rechargeable battery that serves as a power source for the electronic apparatus10. The battery device26is disposed in front of the motherboard24and extends to the left and right along a front end part of the chassis14.

The CPU30and the GPU31are heating elements having the largest amount of heat generated among the electronic components mounted in the chassis14. The cooling module22absorbs and diffuses heat generated by the CPU30and the GPU31and further discharges the heat to the outside of the chassis14. The cooling module22is laminated on the bottom surfaces of the motherboard24and the sub-board25.

FIG.3is a schematic bottom surface view of the cooling module22.

As illustrated inFIGS.2and3, the cooling module22includes vapor chambers36and37arranged on the left and right, a heat pipe38configured with a set of two, a heat pipe39configured with a set of two, one heat pipe45(seeFIG.3), a pair of left and right cooling fins40and41, a pair of left and right air blowing fans42and43, and a heat conduction plate44.

The vapor chambers36and37are plate-shaped heat transport devices. In the vapor chamber36, a closed space is formed between two thin metal plates, and working fluid is enclosed in the closed space. The metal plate is made of a metal with high heat conductivity, such as aluminum, copper, or stainless steel. The closed space S1 is a flow path through which the enclosed working fluid flows while creating a phase change. Examples of the working fluid include water, CFC substitutes, acetone, butane, and the like. Inside the closed space, a wick that sends the condensed working fluid by using the capillarity phenomenon is provided. The wick is formed of, for example, a porous body such as a mesh in which fine metal wires are woven into a cotton shape or a fine flow path.

The vapor chamber37has the same basic configuration as the vapor chamber36described above, except that an outer shape is larger than that of the vapor chamber36and the plate thickness is slightly thinner. That is, in the vapor chamber37, a closed space is formed between two thin metal plates, a wick is provided in the closed space S2, and a working fluid is enclosed. In the vapor chamber37, the material of the metal plate, the type of the working fluid, the configuration of the wick, and the like may be the same as those of the vapor chamber36described above. A notch48having a rectangular shape is formed in a peripheral portion of the GPU31in the vapor chamber37.

The vapor chambers36and37are thin and easily deformed. Therefore, the vapor chambers36and37are reinforced by bonding frames46and47to outer peripheral edge parts or central parts of the top surfaces36aand37a, respectively (seeFIG.2). The frames46and47are made of a metal such as stainless steel and are formed in a frame shape by a rod body thicker than the vapor chambers36and37.

The heat pipe38is a pipe-shaped heat transport device. In the present embodiment, two heat pipes38aand38bare used in parallel in a set of two in front and rear, but one or three or more heat pipes may be used. The heat pipes38aand38bare formed by crushing a metal pipe thinly and flatly into an elliptical cross section shape, and a working fluid is enclosed in a closed space formed in the metal pipe. The metal pipe is made of a metal with high heat conductivity, such as aluminum, copper, or stainless steel. The closed space is a flow path through which the enclosed working fluid flows while creating a phase change. Examples of the working fluid include water, CFC substitutes, acetone, butane, and the like. Inside the closed space, a wick that sends the condensed working fluid by using the capillarity phenomenon is provided. The wick is formed of, for example, a porous body such as a mesh in which fine metal wires are woven into a cotton shape or a fine flow path.

The heat pipes39and45have the same basic configuration as the heat pipe38described above, except that the length and the path are different. That is, the heat pipes39and45are formed by providing a wick in a closed space inside a flatly crushed metal pipe and enclosing a working fluid. Further, the heat pipe39uses two heat pipes39aand39bin parallel in a set of two in front and rear or left and right but may use one or three or more heat pipes. In the heat pipe39, the material of the metal pipe, the type of the working fluid, the configuration of the wick, and the like may be the same as those of the heat pipe38described above. The configuration, action, and manufacturing method of the heat pipes39aand39bwill be further described later.

As illustrated inFIGS.2and3, the cooling fin40on the left has a structure in which a plurality of plate-shaped fins is arranged at equal intervals in the horizontal direction on a surface of the plate. Each fin stands in the vertical direction and extends in the front and rear direction. A gap, through which the air that is sent from the air blowing fan42passes, is formed between the fins adjacent to each other. The cooling fin40is made of a metal having a high heat conductivity such as aluminum or copper.

Since the cooling fin41on the right is symmetrical with the cooling fin40on the left, as the basic configuration, even though the size or the like is slightly different, detailed description will be omitted.

As illustrated inFIGS.2and3, the air blowing fan42on the left is disposed immediately in front of the cooling fin40. That is, the cooling fin40is disposed facing an exhaust port42aopened rearward of the air blowing fan42. The air blowing fan42is a centrifugal fan that rotates an impeller housed inside the fan chassis42bby a motor. The air blowing fan42discharges the air, which is sucked from intake ports42copened on the top and bottom surfaces of the fan chassis42b, in the chassis14from the exhaust port42a. The air blowing from the exhaust port42apasses through the cooling fin40and promotes heat dissipation.

Since the air blowing fan43on the right is symmetrical with the air blowing fan42on the left, as the basic configuration, even though the size or the like is slightly different, detailed description will be omitted. That is, the air blowing fan43also has a rearward-facing exhaust port43aand an intake port43copened on the top and bottom surfaces of the fan chassis43b. The cooling fin41is disposed to face the exhaust port43aof the air blowing fan43.

In the cooling module22configured as described above, the top surface36dof the vapor chamber36abuts the CPU30via a heat receiving plate. Further, the vapor chamber37is formed with the notch48as described above, and the heat pipe39direct abuts the GPU31through the notch48.

The central part of the heat pipe38is curved to the front and extends in the horizontal direction as a whole. The heat pipe38is bonded to the bottom surface36eof the vapor chamber36at a position where the substantially central part, which is a heat receiving part, overlaps with the CPU30. The left end part of one heat pipe38ais bonded to the bottom surface of the cooling fin40, and the right end part of the one heat pipe38apasses over a bridge part60and is bonded to the bottom surface37bof the vapor chamber37. The left end part of the other heat pipe38bis bonded to the bottom surface of the cooling fin40, and the right end part of the other heat pipe38bpasses over the bridge part60, passes through the bottom surface37bof the vapor chamber37, and is bonded to the bottom surface of the cooling fin41. Most portion of the heat pipe38is bonded to the bottom surfaces36band37bof each of the vapor chambers36and37.

The heat pipe39is disposed in a substantially L shape as a whole. The heat pipe39is bonded to the bottom surface37bof the vapor chamber37at a position where the substantially central part, which is a heat receiving part, overlaps with the GPU31. The right end part of the heat pipe39is bonded to the bottom surface of the cooling fin41, and the front end part of the heat pipe39passes through the vapor chamber37and is bonded to the bottom surface of the heat conduction plate44. The two heat pipes39aand39bfollow substantially the same path in parallel. Most portion of the heat pipe39is bonded to the bottom surface37bof the vapor chamber37. The heat pipe45is disposed in a substantially L shape as a whole and is in contact with the heat pipe38band the heat pipe39a. By interposing the heat pipe45, the heat resistance between the heat pipe38band the heat pipe39ais reduced, and a cooperative cooling action can be obtained.

As a result, the heat, which is generated by the CPU30and GPU31, is absorbed and diffused in the vapor chambers36and37and the heat pipe39, and is efficiently transported to the cooling fins40and41via the heat pipes38,39, and45, and then is discharged to the outside of the chassis14by the air blowing from the air blowing fans42and43. Note that, in the present embodiment, the vapor chambers36and37are connected by the bridge part60, but the vapor chambers36and37may be independent of each other.

Next, the configuration and the action and effect of the heat pipe39will be further described.FIG.4is a partially enlarged perspective view of the cooling module22viewed from a side opposite toFIG.3.FIG.5is a schematic cross-sectional side view of the cooling module22and a GPU31.

As illustrated inFIGS.4and5, the heat pipes39aand39bare adjacent to and parallel to each other in the horizontal direction and each of cross sections has a rectangular shape. In this embodiment, the heat pipe39ahas a larger cross-sectional area than that of the heat pipe39b. The heat pipes39aand39bare put together with a fixture49.

In a cross-sectional shape of the heat pipe39a, the lengths of the side surfaces39aband39acare shorter than those of the top surface39aaand the bottom surface39adwhich are the heat receiving surfaces, and the height H including the fixture49is set low. The fixture49is sufficiently thinner than the heat pipes39aand39b, and substantially occupied by the heat pipes39aand39bin terms of the height H. In a cross-sectional shape of the heat pipe39b, the lengths of the side surfaces39bband39bcare shorter than those of the top surface39baand the bottom surface39bdwhich are the heat receiving surfaces, and the height H including the fixture49is set low. The heights of the heat pipe39aand the heat pipe39bin the vertical direction are the same. Hereinafter, the top surfaces39aaand39baare also referred to as heat receiving surfaces39aaand39ba.

The heat pipe39ahas a rectangle-shaped cross section, and the heat receiving surface39aaand the bottom surface39ad, and the side surfaces39aband39acare orthogonal to each other. The heat pipe39bhas a rectangle-shaped cross section, and the top surface39baand the bottom surface39bd, and the side surfaces39bband39bcare orthogonal to each other.

The heat pipes39aand39bare slightly upward such that the heat pipes39aand39benter the notch48at a location of the notch48, and the heat receiving surfaces39aaand39baare in direct contact with the GPU31. Since the heat receiving surfaces39aaand39baare in direct contact with the GPU31, good heat transfer property is provided. However, the direct contact here includes the interposition of grease or the like having substantially no thickness. The heat pipes39aand39bare wide in the horizontal direction and are in contact with the entire bottom surface of the GPU31. The side surface of the heat pipe39aand the side surface of heat pipe39b, which face each other, are in surface contact with each other, that is, the side surface39aband the side surface39bbare in surface contact with each other.

The fixture49is formed, for example, by performing a bending process on a metal plate and includes a crossing part49a, a pair of vertical walls49b, a pair of fold back parts49c, and a pair of fixing pieces49d. The crossing part49aabuts the bottom surfaces39adand39bdsuch that the crossing part49acrosses the heat pipes39aand39b. The vertical wall49babuts the side surfaces39acand39bcsuch that the vertical wall49asuppresses the heat pipes39aand39bfrom both the left and right sides. That is, the crossing part49aand the vertical wall49bhave a U-shaped cross section, and the heat pipes39aand39bare bundled and fixed.

The fold back part49cis connected from the end part of the vertical wall49b, slightly enters the notch48, and is positioned such that the heat receiving surfaces39aaand39baof the heat pipes39aand39babut the GPU31. The fixing piece49dis connected from the end part of the vertical wall49band abuts and is fixed to the bottom surface37bof the vapor chamber37. The fixing piece49dand the vapor chamber37are fixed by welding or adhesion. The fixture49has even higher strength when the fixture49is die-cast formed and when a location corresponding to the fold back part49cis made into a thick wall shape without folding back. Further, the fixing piece49dmay abut and be fixed to the top surface37awithout the fold back part49c.

According to the cooling module22of the electronic apparatus10configured in this way, the two heat pipes39aand39bare in direct contact with the entire bottom surface of the GPU31, and the cooling performance is improved as compared with a case where one heat pipe is used. The heights H of the heat pipes39aand39band the fixture49are sufficiently low, and the electronic apparatus10can be made thinner.

The heat pipe39aand the heat pipe39bare in surface contact with each other on the side surface39aband the side surface39bb, and act in cooperation with each other because the heat resistance of each other is low, thereby well-balanced heat dissipation is performed without biasing the heat load to either one. The two heat pipes39aand39bcan be easily formed to bend toward the cooling fin41(seeFIG.2) as compared with a case where one thick heat pipe is used.

Further, since the heat pipe39bhas a smaller cross-sectional area than that of the heat pipe39a, the heat pipe39bis easy to bend, thereby the heat pipe39bis provided inwardly having a large curvature at a location where the heat pipe39bbends toward the cooling fin41. By making the heat pipe39aand the heat pipe39bhave different cross-sectional areas, it is easy to match the width of the GPU31to be contacted.

However, depending on the design conditions, the cross-sectional areas of the heat pipe39aand the heat pipe39bmay be the same. The number of heat pipes39in contact with the GPU31may be three or more. A similar structure in which the heat pipes39aand39bare in contact with the GPU31from the notch48may be applied to a heat transfer part between the CPU30and the heat pipes38aand38b.

Next, regarding the method of manufacturing the electronic apparatus10, particularly the method of manufacturing the heat pipes39aand39bwill be described.FIGS.6A to6Dare views describing the manufacturing step of the heat pipes39aand39b,FIG.6Ais a schematic cross-sectional view illustrating materials39Aa and39Ab of the heat pipes39aand39b,FIG.6Bis a schematic cross-sectional view for describing a first forming step,FIG.6Cis a schematic cross-sectional view for describing a second forming step, andFIG.6Dis a schematic cross-sectional view in a state in which the second forming step is ended.FIG.7is a flowchart illustrating the method of manufacturing the heat pipes39aand39b.FIG.8is a schematic side view for describing a first forming step.

The heat pipes39aand39bare manufactured by using the cylindrical materials39Aa and39Ab as illustrated inFIG.6A. The material39Aa of the heat pipe39ahas a slightly larger cross-sectional area than that of the material39Ab of the heat pipe39b. A predetermined amount of wick is put in each of the materials39Aa and39Ab.

In step S1ofFIG.7, each of perfect circular materials39Aa and39Ab is pressed by a predetermined section to obtain elliptical-shaped preliminary processing materials39Ba and39Bb (seeFIG.6B).

In step S2(the first forming step), the elliptical-shaped preliminary processing material39Ba is inserted into a rectangular groove50aof a first die50, and the preliminary processing material39Bb is inserted into a rectangular groove51aof a first die51, and then each of the preliminary processing materials39Ba and39Bb is pressed from above. The first dies50and51have the substantially same length as the preliminary processing materials39Ba and39Bb, respectively. The rectangular grooves50aand51aare formed along the long-length direction of the first dies50and51and are open upward.

The horizontal width of the rectangular groove50ais slightly larger than the horizontal width of the elliptical-shaped preliminary processing material39Ba (length in the longitudinal direction inFIGS.6A to6D), and the depth is slightly shallower than the height of the preliminary processing material39Ba (length in the short-length direction inFIGS.6A to6D). The horizontal width of the rectangular groove51ais slightly larger than the horizontal width of the elliptical-shaped preliminary processing material39Bb (length in the longitudinal direction in FIGS.6A to6D), and the depth is slightly shallower than the height of the preliminary processing material39Bb (length in the short-length direction inFIGS.6A to6D).

Step S2is performed by using the pressing machine53as illustrated inFIG.8. The pressing machine53has a die53awhich is a main body and a plurality of rollers53bprovided on the bottom surface of the die53a. The die53ais a block having a moderate weight. The plurality of rollers53bare provided on the bottom surface of the die53aat narrow intervals. Each roller53bis rotatable about an axis orthogonal to a direction in which the pressing machine53is moved (the direction of the arrow inFIG.8).

The pressing machine53is moved along the long-length direction of the first die50by a manual operation or a predetermined driving machine in a state in which the pressing machine53is placed on the top surface of the first die50. As the pressing machine53moves, the roller53bpresses a portion of the preliminary processing material39Ba that protrudes from the rectangular groove50a. The preliminary processing material39Ba is formed in the same rectangular shape as the rectangular groove50aby the plurality of rollers53apressing the preliminary processing material39Ba while rolling, and then a primary formed body39Ca (seeFIG.6C) is obtained.

Although not illustrated, the elliptical-shaped preliminary processing material39Bb that is inserted into the rectangular groove51aof the first die51is also formed in the same rectangular shape as the rectangular groove51aby the pressing machine53, and the primary formed body39Cb (seeFIG.6C) is obtained. However, the primary formed bodies39Ca and39Cb are not limited to a rectangular shape having four right-angled parts in a strict sense, and may be a substantially rectangular shape such that corner parts have a small chamfered shape, for example. The preliminary processing materials39Ba and39Bb may be pressed by the weight of the pressing machine53, or may be pressed by a combination of predetermined pressurizing sections. Further, step S1may be omitted and the perfect circular-shaped material may be directly inserted into the first dies50and51and pressed by the pressing machine53, but higher dimensional accuracy can be obtained by performing the preliminary processing on the material into an elliptical shape in step S1once (or a plurality of times).

In step S3(the second forming step), two rectangular-shaped primary formed bodies39Ca and39Cb are inserted side by side into the rectangular groove52aof a second die52, and the two primary formed bodies39Ca and39Cb are pressed from above at the same time. The second die52has the same length as that of the primary formed bodies39Ca and39Cb. The rectangular groove52ais formed along the long-length direction of the second die52and opens upward.

The horizontal width of the rectangular groove52ais slightly larger than the combined horizontal width of the two rectangular-shaped primary formed bodies39Ca and39Cb, and the depth is shallower than the depths of any of the primary formed bodies39Ca and39Cb. As illustrated inFIG.6C, the rectangular-shaped primary formed bodies39Ca and39Cb are placed horizontally and are arranged side by side in the rectangular groove52ain the horizontal width direction, and each one surface is exposed to an opening side.

In the same manner as in step S2above, the primary formed bodies39Ca and39Cb are pressed from above at the same time by the pressing machine53. The primary formed bodies39Ca and39Cb are formed in the same rectangular shape as the rectangular groove52a(seeFIG.6D) by the plurality of rollers53apressing the primary formed bodies39Ca and39Cb while rolling, and then the heat pipes39aand39bare obtained. The heat pipes39aand39bare not limited to a rectangular shape having four right-angled parts in a strict sense, and may be a substantially rectangular shape such that corner parts have a small chamfered shape, for example.

As illustrated inFIG.6D, the side surfaces39aband39bbof the obtained heat pipes39aand39bare in surface contact with each other with substantially no gap. This is because the two rectangular-shaped primary formed bodies39Ca and39Cb are arranged in the rectangular groove52aand pressed at the same time. When step S2is omitted and the two circular or elliptical intermediate bodies are formed by the second die52, the amount of processing deformation becomes large, and it is difficult to form the heat pipes39aand39binto a proper rectangular shape. In contrast to this, in the present embodiment, since the intermediate bodies are formed in a rectangular shape by the preliminary processing in step S2, the heat pipes39aand39bthat are the final products can be formed in a wide and thin proper rectangular shape.

Further, since the rectangular groove52ahas a rectangle-shaped cross section, the four side surfaces39ab,39ac,39bb, and39bcare formed such that the four side surfaces39ab,39ac,39bb, and39bcare orthogonal to the heat receiving surfaces39aa,39ba, respectively, and each of the heat pipes39aand39balso has a proper rectangular shape. That is, the cross sections of the heat pipes39aand39bdo not have a locally narrowed or distorted shape, and the internal wick is not damaged. Further, local excessive strain stress does not remain. Note that, an intermediate forming step may be interposed between step S1and step S2.

In step S4(an assembly step), the heat pipes39aand39bobtained as described above are put together with the fixture49, are fixed to the vapor chamber37, and assembled such that the heat receiving surfaces39aaand39baare thermally connected to the GPU31.

The heat pipes39aand39bmanufactured in this manner are widely and thinly formed and can be suitably applied to a thin electronic apparatus10.

The present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be freely changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS

10electronic apparatus22cooling module36,37vapor chamber38,38a,38b,39,39a,39b,45heat pipe39aa,39batop surface (heat receiving surface)39Aa,39Ab material39Ba,39Bb preliminary processing material39Ca,39Cb primary formed body48notch49fixture50,51first die50a,51arectangular groove52second die52arectangular groove53pressing machine