LAMINATED STRUCTURE, HEAT CONDUCTIVE STRUCTURE, AND METHOD FOR MANUFACTURING HEAT CONDUCTIVE STRUCTURE

Abstract

To provide a laminated structure, a heat conduction structure, and a method for manufacturing a heat conduction structure that can efficiently disperse heat.SOLUTION: A heat conduction structure comprises: a fluorescent material 10; and a laminated structure 20 that is joined to the fluorescent material 10, and includes a first laminate 30 and a second laminate 40 in which a graphite layer and metal material are laminated. The first laminate 30 is placed on the second laminate 40 so that a first direction being a lamination direction of the first laminate 30 and a second direction being a lamination direction of the second laminate 40 have an intersecting relationship.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a laminated structure, a thermally conductive structure, and a method for manufacturing a thermally conductive structure. [Background technology]

[0002] For example, Patent Document 1 discloses a structure having a first thermal conductor having a graphene sheet laminated thereon and a second thermal conductor having a laminated direction that coincides with the lamination direction of the first thermal conductor having a graphene sheet laminated thereon, as a thermal conductive structure for dissipating heat from a heat generating body. The heat generating body is, for example, a phosphor used in the light source of a projector. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-112334 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the configuration of Patent Document 1 has the problem that heat from the heat generating body can be transmitted only in one direction, making it difficult to diffuse heat efficiently. In particular, when the heat source is a phosphor, there is a problem that thermal decay is likely to occur, and the light conversion efficiency of the phosphor is extremely reduced. [Means for solving the problem]

[0005] The laminated structure is a laminated structure formed by laminating graphite layers each having a surface modified with a metal material, and the surfaces of the laminated structure, including the end faces, are surface-modified with the metal material.

[0006] The thermal conduction structure comprises a heat source, and a laminate structure joined to the heat source and including a first laminate and a second laminate in which a graphite layer and a metal material are laminated, wherein the first laminate and the second laminate are stacked such that a first direction which is the stacking direction of the first laminate and a second direction which is the stacking direction of the second laminate intersect with each other.

[0007] A method for manufacturing a thermally conductive structure includes the steps of: surface-modifying a graphite sheet with a metal material to form a graphite layer; stacking the graphite layers to form a first laminate and a second laminate; surface-modifying each of the first laminate and the second laminate with the metal material; arranging the first laminate and the second laminate such that a first direction, which is a stacking direction of the first laminate, and a second direction, which is a stacking direction of the second laminate, intersect with each other; joining a heat source to the first laminate via a bonding material; and joining a thermally conductive substrate to the second laminate via the bonding material. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a projector. [Diagram 2] FIG. 1 is a schematic diagram showing a configuration of a lighting device. [Diagram 3] FIG. 1 is a perspective view showing a configuration of a heat conducting structure according to a first embodiment. [Figure 4] FIG. 4 is a side view showing the configuration of a heat conducting structure. [Diagram 5] FIG. 2 is an exploded perspective view showing the configuration of a laminated structure. [Figure 6] 6 is a cross-sectional view taken along line AA' of the first laminate shown in FIG. 5. [Figure 7] FIG. 4 is an exploded perspective view showing the first laminate; [Figure 8] 8 is a cross-sectional view of the graphite layer taken along line BB' shown in FIG. 7. [Figure 9] FIG. 4 is an exploded perspective view showing the second laminate; [Figure 10] A diagram showing the properties of graphite sheets. [Figure 11]4 is a flowchart showing a method for manufacturing a thermal conductive structure. [Figure 12] FIG. 6 is a perspective view showing the configuration of a heat conduction structure according to a second embodiment. [Figure 13] 13 is a side view showing the configuration of the heat conducting structure shown in FIG. 12. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, the configuration of a projector 1000 according to the present embodiment will be described with reference to FIG.

[0010] As shown in FIG. 1, the projector 1000 includes an illumination device 1200, a color separation optical system 1300, light modulation devices 1400R, 1400G, and 1400B, a light combining optical system 1500, and a projection optical system 1600.

[0011] The illumination device 1200 emits white illumination light WL. A specific configuration of the illumination device 1200 will be described later. The color separation optical system 1300 separates the illumination light WL from the illumination device 1200 into red light LR, green light LG, and blue light LB. The light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B modulate the red light LR, the green light LG, and the blue light LB according to image information, respectively, to form image light of each color. The light combining optical system 1500 combines the image light of each color from each of the light modulation devices 1400R, 1400G, and 1400B. The projection optical system 1600 projects the combined image light from the light combining optical system 1500 toward the screen SCR.

[0012] The color separation optical system 1300 includes a first dichroic mirror 1700a, a second dichroic mirror 1700b, a first reflecting mirror 1800a, a second reflecting mirror 1800b, a third reflecting mirror 1800c, a first relay lens 1900a, and a second relay lens 1900b.

[0013] The first dichroic mirror 1700a separates the illumination light WL emitted from the illumination device 1200 into red light LR, green light LG, and blue light LB. That is, the first dichroic mirror 1700a has a property of transmitting the red light LR and reflecting the green light LG and blue light LB.

[0014] The second dichroic mirror 1700b separates the mixed light of the green light LG and the blue light LB into the green light LG and the blue light LB. That is, the second dichroic mirror 1700b has a property of reflecting the green light LG and transmitting the blue light LB.

[0015] The first reflecting mirror 1800a is disposed in the optical path of the red light LR and reflects the red light LR transmitted through the first dichroic mirror 1700a toward the optical modulation device 1400R. The second reflecting mirror 1800b and the third reflecting mirror 1800c are disposed in the optical path of the blue light LB and guide the blue light LB transmitted through the second dichroic mirror 1700b to the optical modulation device 1400B. The second dichroic mirror 1700b reflects the green light LG toward the optical modulation device 1400G.

[0016] The first relay lens 1900a and the second relay lens 1900b are disposed after the second dichroic mirror 1700b in the optical path of the blue light LB. The first relay lens 1900a and the second relay lens 1900b compensate for optical loss of the blue light LB caused by the optical path length of the blue light LB being longer than the optical path lengths of the red light LR and the green light LG.

[0017] Each of the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B is composed of a liquid crystal panel. Each of the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B modulates each of the red light LR, the green light LG, and the blue light LB according to image information while passing each of the red light LR, the green light LG, and the blue light LB, and forms image light corresponding to each color. Polarizing plates (not shown) are arranged on the light input side and the light output side of each of the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B.

[0018] Field lenses 1010R, 1010G, and 1010B are provided on the light incident side of each of the optical modulation devices 1400R, 1400G, and 1400B, which parallelize the red light LR, green light LG, and blue light LB incident on each of the optical modulation devices 1400R, 1400G, and 1400B.

[0019] The light combining optical system 1500 is composed of a cross dichroic prism. The light combining optical system 1500 combines the image light of each color from the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B, and emits the combined image light toward the projection optical system 1600.

[0020] The projection optical system 1600 is composed of a group of projection lenses. The projection optical system 1600 enlarges and projects the image light combined by the light combining optical system 1500 toward the screen SCR. That is, the projection optical system 1600 projects the light modulated by each of the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B onto the screen SCR. As a result, an enlarged color video (image) is displayed on the screen SCR.

[0021] Next, the configuration of the lighting device 1200 will be described with reference to FIG.

[0022] 2, the illumination device 1200 includes a first light source device 1210, a second light source device 1220, a dichroic mirror 1230, and a uniform illumination optical system 1240. The first light source device 1210 includes a first light source 520, a second light source 521, and a wavelength conversion unit 522.

[0023] The first light source 520 is composed of a semiconductor laser that emits excitation light B1 consisting of laser light in a first wavelength band. The second light source 521 has the same configuration as the first light source 520. That is, the second light source 521 is composed of a semiconductor laser that emits excitation light B2 consisting of laser light in a first wavelength band. Here, the light in the first wavelength band corresponds to light having an emission intensity peak at, for example, 430 nm to 480 nm, and in this embodiment, light having an emission intensity peak of about 445 nm is used as the excitation light B1, B2.

[0024] The first light source 520 or the second light source 521 may be composed of one semiconductor laser or multiple semiconductor lasers. The first light source 520 and the second light source 521 may also use a semiconductor laser that emits a blue laser light of a wavelength other than 445 nm, for example, 460 nm.

[0025] Furthermore, the first light source 520 and the second light source 521 may be other light sources such as light emitting diodes (LEDs) instead of semiconductor lasers.

[0026] In this embodiment, the excitation light B1, B2 emitted from the first light source 520 and the second light source 521 enter the wavelength conversion unit 522. The wavelength conversion unit 522 converts the excitation light B1, B2 into fluorescent light (converted light) Y of a second wavelength band different from the first wavelength band. Here, the light of the second wavelength band corresponds to yellow light having a peak emission intensity at 520 nm to 580 nm, for example. The second wavelength band can be in the range of 500 nm to 700 nm, which is a wavelength band constituting yellow.

[0027] Wavelength conversion section 522 includes phosphor 10 as a heat source, glass plates 514 and 515, reflective layers 524 and 525, a silver mirror 526, and a pickup lens 527. In this embodiment, phosphor 10 has a flat plate shape having multiple surfaces, and converts excitation light B1 incident from first light source 520 and excitation light B2 incident from second light source 521 into fluorescent light (converted light) Y of a second wavelength band different from the first wavelength band. Specifically, phosphor 10 is a hexahedron.

[0028] In this embodiment, the phosphor 10 includes phosphor particles (not shown) that convert the excitation light B1, B2 into the fluorescent light Y. For example, a YAG (yttrium aluminum garnet) phosphor is used as the phosphor particles. The phosphor particles may be formed of one material, or a mixture of particles formed of two or more materials may be used. The phosphor 10 is preferably formed by dispersing phosphor particles in an inorganic binder such as alumina, or by sintering phosphor particles without using a binder.

[0029] The dichroic mirror 1230 is disposed in the optical path from the first light source device 1210 to the uniform illumination optical system 1240 and in the path from the second light source device 1220 to the uniform illumination optical system 1240 so as to intersect at an angle of 45° with respect to each of the optical axis of the first light source device 1210 (corresponding to the illumination optical axis 700ax of the illumination device 1200) and the optical axis 600ax of the second light source device 1220. The dichroic mirror 1230 reflects blue light B (described later) emitted from the second light source device 1220 and transmits yellow fluorescent light Y emitted from the first light source device 1210.

[0030] The second light source device 1220 includes a light source 671 , a light collecting optical system 672 , a scattering plate 673 , and a collimating optical system 674 .

[0031] The light source 671 is composed of the same semiconductor laser as the first light source 520 of the first light source device 1210. The light source 671 may be composed of one semiconductor laser, or may be composed of multiple semiconductor lasers. The light source 671 may also be composed of an LED.

[0032] The light collecting optical system 672 includes a first lens 672a and a second lens 672b. The light collecting optical system 672 collects blue light B emitted from the light source 671 onto a scattering plate 673 or in the vicinity of the scattering plate 673. The first lens 672a and the second lens 672b are each formed of a convex lens.

[0033] The scattering plate 673 scatters the blue light B from the light source 671 to generate blue light B having a light distribution close to the light distribution of the fluorescent light Y emitted from the first light source device 1210. As the scattering plate 673, for example, ground glass made of optical glass can be used.

[0034] The collimating optical system 674 includes a first lens 674a and a second lens 674b. The collimating optical system 674 approximately collimates the light emitted from the scattering plate 673. The first lens 674a and the second lens 674b are each formed of a convex lens.

[0035] The blue light B emitted from the second light source device 1220 is reflected by the dichroic mirror 1230 and combined with the fluorescent light Y emitted from the first light source device 1210 and transmitted through the dichroic mirror 1230 to become white illumination light WL. The illumination light WL is incident on the uniform illumination optical system 1240.

[0036] The uniform illumination optical system 1240 includes a first lens array 720 , a second lens array 730 , a polarization conversion element 740 , and a superimposing lens 750 .

[0037] The first lens array 720 has a plurality of first lenses 720a for splitting the illumination light WL into a plurality of partial light beams. The plurality of first lenses 720a are arranged in a matrix in a plane perpendicular to the illumination optical axis 700ax.

[0038] The second lens array 730 has a plurality of second lenses 730a corresponding to the plurality of first lenses 720a of the first lens array 720. The second lens array 730, together with the superimposing lens 750, forms an image of each of the first lenses 720a of the first lens array 720 in the vicinity of the image forming areas of the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B. The plurality of second lenses 730a are arranged in a matrix in a plane perpendicular to the illumination optical axis 700ax.

[0039] The polarization conversion element 740 converts into linearly polarized light the light emitted from the second lens array 730. The polarization conversion element 740 includes, for example, a polarization separation film and a phase difference plate (both not shown).

[0040] The superimposing lens 750 collects the partial light beams emitted from the polarization conversion element 740 and superimposes them near the image forming areas of the light modulation device 1400R, the light modulation device 1400G, and the light modulation device 1400B shown in FIG.

[0041] As a result, the illumination device 1200 emits illumination light WL having a substantially uniform illuminance distribution toward the color separation optical system 1300.

[0042] Next, the configuration of the heat conducting structure 100 of the first embodiment will be described with reference to FIGS.

[0043] As shown in FIG. 3, the thermal conductive structure 100 of the first embodiment includes a phosphor 10 as a heat source, a laminated structure 20 bonded to the phosphor 10, a thermal conductive substrate 50 bonded to the laminated structure 20, and a heat sink 60 bonded to the thermal conductive substrate 50.

[0044] As described above, phosphor 10 converts the wavelength of the laser light from first light source 520 and second light source 521. The size of phosphor 10 is, for example, 4 mm×4 mm in plan view.

[0045] The laminated structure 20 has a first laminate 30 and a second laminate 40, which are larger in size than the phosphor 10 in a plan view. The size of the laminated structure 20 is, for example, 8 mm×8 mm in a plan view. The thickness of the laminated structure 20 is, for example, 1 mm. As shown in FIG. 5, the first laminate 30 is configured by stacking a plurality of graphite layers 31 in the X direction. As shown in FIG. 5, the second laminate 40 is configured by stacking a plurality of graphite layers 31 in the Y direction.

[0046] As shown in FIG. 5, the first laminate 30 and the second laminate 40 are stacked and arranged such that a first direction, which is the stacking direction of the first laminate 30, and a second direction, which is the stacking direction of the second laminate 40, intersect with each other.

[0047] Specifically, first laminate 30 and second laminate 40 are formed by laminating graphite layers 31 and metal materials 34 (see FIG. 6). The pitch width of graphite layers 31 in first laminate 30 and the pitch width of graphite layers 31 in second laminate 40 are, for example, the same.

[0048] The thermally conductive substrate 50 is made of copper (Cu) or a composite material of carbon (C) and copper (Cu). The thermally conductive substrate 50 is joined to a heat sink 60 and efficiently cools the heat generated by the phosphor 10. This makes it possible to prevent a decrease in the luminous efficiency of the phosphor 10.

[0049] The heat sink 60 is made of a material such as aluminum (Al). When the phosphor 10 is made to emit light as a point light source, the heat generated by the wavelength conversion by the phosphor 10 is concentrated at one point, resulting in an extremely high temperature. When the temperature of the phosphor 10 reaches, for example, 200° C. or higher, the wavelength conversion efficiency of the phosphor 10 drops rapidly. In other words, there is a risk of thermal breakdown.

[0050] However, by using a laminated structure 20 in which a first laminate 30 and a second laminate 40 are arranged so that the stacking directions cross, the heat of the phosphor 10 can be rapidly spread in the first and second directions and transferred to the thermally conductive substrate 50 and the heat sink 60, thereby enabling efficient cooling and preventing a decrease in the light conversion efficiency of the phosphor 10 and thermal breakdown.

[0051] 4, the phosphor 10 and the laminated structure 20 are bonded together by a bonding material 11a. The laminated structure 20 and the thermally conductive substrate 50 are bonded together by a bonding material 11b. The thermally conductive substrate 50 and the heat sink 60 are bonded together by a bonding material 11c. Examples of the bonding materials 11a, 11b, and 11c include bonding materials containing silver (Ag) nanoparticles.

[0052] Next, the configurations of the first laminate 30 and the second laminate 40 will be described with reference to FIGS.

[0053] As shown in Fig. 6, first laminate 30 has a plurality of graphite layers 31 laminated with metal material 34 interposed therebetween. Specifically, as shown in Fig. 7, first laminate 30 has a plurality of substantially rectangular plate-shaped graphite layers 31 laminated in the X direction on the paper surface of Fig. 7. That is, a plurality of graphite layers 31 are laminated in the first direction. Note that Fig. 7 does not show metal material 34 for bonding a plurality of graphite layers 31 together.

[0054] 8, in graphite layer 31, the surface of graphite sheet 32 ​​is modified with metal material 33. That is, graphite sheet 32 ​​is metallized. As a method of surface modification, for example, there is a method of performing electrolytic plating using copper (Cu) as metal material 33. The thickness of the electrolytic plating is, for example, 0.1 μm.

[0055] Since the surface of graphite sheet 32 ​​is modified with copper, heat can be diffused uniformly. Furthermore, when first laminate 30 and second laminate 40 are formed by laminating graphite layer 31, the thermal resistance between the laminates can be reduced.

[0056] 10, graphite sheet 32 ​​has a relatively high thermal conductivity of 1600 W / m·K. For example, the thermal conductivity of copper (Cu) is 400 W / m·K. On the other hand, graphite sheet 32 ​​has a linear expansion coefficient of 0.93 ppm / °C, which is smaller than those of metals such as gold (Au) and copper (Cu), and has a high specific resistance. Thus, graphite sheet 32 ​​is an effective material for efficiently conducting heat, as well as for preventing distortion and stress due to bonding and ensuring electrical conductivity.

[0057] 9, second laminate 40 has a plurality of graphite layers 31 laminated with metal material 34 interposed therebetween. Specifically, in second laminate 40, a plurality of graphite layers 31 are laminated in the Y direction on the paper surface of FIG. 9. That is, a plurality of graphite layers 31 are laminated in the second direction. Note that FIG. 9 omits illustration of metal material 34 for bonding a plurality of graphite layers 31 together.

[0058] Next, a method for manufacturing the thermal conducting structure 100 will be described with reference to FIGS.

[0059] First, a method for forming the first laminate 30 and a method for forming the second laminate 40 will be described. Note that since the first laminate 30 and the second laminate 40 are formed by the same manufacturing method, the manufacturing method of the first laminate 30 will be mainly described.

[0060] 11, in step S11, surface modification (in other words, metallization) is performed on the surface of graphite sheet 32. Examples of surface modification include plating with copper (Cu) or sputtering with titanium (Ti) or copper (Cu) to increase affinity with copper (Cu) to be formed later.

[0061] In step S12, graphite layer 31 is laminated. Specifically, metal powder or foil such as copper is placed between graphite layers 31, laminated, and pressed. When using copper foil, a copper foil having a thickness of about 20 μm is prepared, and graphite layer 31 and copper foil are laminated alternately. By alternately laminating graphite layer 31 and copper foil, the volume fraction of graphite layer 31 can be set to 60% or more, and the thermal conductivity of the laminate can be set to 1000 W / m·K. Note that, without using metal powder or metal foil, a thick graphite layer with a surface modification may be laminated. By not using metal powder or metal foil, the volume fraction of graphite layer 31 can be increased, and further, the thermal conductivity of the laminate can be increased to 1600 W / m·K for graphite sheet 32 ​​itself.

[0062] In step S13, the first laminate 30 is sintered. Specifically, the pressurized graphite layer 31 and the metal material 34 are subjected to spark plasma sintering (SPS). In spark plasma sintering, the laminate in a vacuum is sintered by Joule heat while an electric current is passed, so that it is possible to perform sintering more effectively with fewer voids and with higher quality. Note that the graphite sheet 32 ​​has high conductivity as shown in FIG. 10, so that spark plasma sintering is possible. In this manner, a laminate precursor (not shown) is formed before it becomes the first laminate 30.

[0063] In step S14, the laminate precursor is cut into individual pieces. Specifically, the sintered laminate precursor is cut (sliced) to the size of the first laminate 30. This results in the individualized first laminate 30.

[0064] In step S15, the first laminate 30 is surface-modified. Specifically, by cutting the laminate precursor into individual pieces, for example, the surface including the end face of the graphite sheet 32 ​​is exposed. When exposed, the fragile graphite sheet 32 ​​becomes easily broken. Therefore, the first laminate 30 is surface-modified again with a metal material 34 such as copper (Cu) to prevent the graphite sheet 32 ​​from being exposed on the surface. In addition, by performing the surface modification again, when the first laminate 30 and the second laminate 40 are joined, the adhesion can be improved and heat can be easily diffused.

[0065] Next, a method for forming the thermally conductive substrate 50 will be described. In step S21, the thermally conductive substrate 50 is formed. As described above, the thermally conductive substrate 50 is formed of copper (Cu) or a composite material of carbon (C) and copper (Cu). Then, in step S22, the surface of the thermally conductive substrate 50 is cleaned.

[0066] In step S31, the first laminate 30 and the second laminate 40 are bonded together. Specifically, the first laminate 30 and the second laminate 40 are arranged so that the lamination direction of the first laminate 30 and the lamination direction of the second laminate 40 cross each other. The first laminate 30 and the second laminate 40 are laminated and pressed together by arranging metal powder or foil such as copper. In addition, the laminated structure 20 and the thermally conductive substrate 50 are bonded together via the bonding material 11b.

[0067] Next, a description will be given of a method for forming the phosphor 10. In step S41, the phosphor 10 is formed. In step S42, the surface of the phosphor 10 is cleaned.

[0068] In step S51, the phosphor 10 is bonded. Specifically, the phosphor 10 and the laminated structure 20 are bonded with the bonding material 11a containing the above-mentioned silver nanoparticles.

[0069] In step S52, the heat sink 60 is bonded. Specifically, the laminated structure 20 and the thermally conductive substrate 50 are bonded with a bonding material 11b, and the thermally conductive substrate 50 and the heat sink 60 are bonded with a bonding material 11c. In this manner, the thermally conductive structure 100 is completed.

[0070] As described above, according to the first embodiment, the laminated structure 20 is formed by stacking graphite layers 31 each having a surface-modified with a metal material 33, and the surfaces of the laminated structure 20 including the end faces are surface-modified with a metal material 34.

[0071] According to this configuration, the surfaces of laminated structure 20, including the end faces, are surface-modified with metal material 34, so that it is possible to prevent graphite layer 31 from being destroyed, and heat can be diffused via graphite layer 31 and metal material 34.

[0072] Furthermore, the thermal conduction structure 100 of the first embodiment comprises a phosphor 10, and a laminate structure 20 including a first laminate 30 and a second laminate 40 joined to the phosphor 10 and in which a graphite layer 31 and a metal material 34 are laminated, and the first laminate 30 and the second laminate 40 are stacked such that a first direction which is the stacking direction of the first laminate 30 and a second direction which is the stacking direction of the second laminate 40 intersect with each other.

[0073] According to this configuration, the first laminate 30 and the second laminate 40 are stacked so that the first direction, which is the stacking direction of the first laminate 30, and the second direction, which is the stacking direction of the second laminate 40, intersect, so that heat from the phosphor 10 can be diffused in the intersecting first and second directions, and heat can be dissipated efficiently. Also, in the case of the phosphor 10, it is possible to suppress thermal decay, and it is possible to suppress a decrease in the light conversion efficiency of the phosphor 10.

[0074] In addition, it is possible to efficiently dissipate the heat of the phosphor 10, prevent the phosphor 10 from overheating, and prevent thermal decay of the phosphor 10, thereby ensuring a larger amount of excitation light. Also, it is possible to realize a projector 1000 that is compact, has high brightness, and has a high luminous flux.

[0075] Moreover, graphite layer 31 is preferably formed by surface-modifying graphite sheet 32 ​​with metal material 33. According to this configuration, by surface-modifying graphite sheet 32 ​​with metal material 33, it is possible to prevent graphite layer 31 from being destroyed, and graphite layer 31 can be laminated.

[0076] Moreover, it is preferable that a thermally conductive substrate 50 is joined to the laminated structure 20 on the side opposite to the phosphor 10. According to this configuration, since the thermally conductive substrate 50 is joined to the laminated structure 20 on the side opposite to the phosphor 10, the heat diffused in the first and second directions by the laminated structure 20 can be dissipated to the outside via the thermally conductive substrate 50.

[0077] Moreover, it is preferable that a heat sink 60 is joined to the thermally conductive substrate 50 on the side opposite to the laminated structure 20. According to this configuration, since the heat sink 60 is joined to the thermally conductive substrate 50, heat can be dissipated efficiently.

[0078] Moreover, the method for manufacturing the thermally conductive structure 100 of the first embodiment includes the steps of: surface-modifying the graphite sheet 32 ​​with a metal material 33 to form a graphite layer 31; stacking the graphite layer 31 to form a first laminate 30 and a second laminate 40; surface-modifying the first laminate 30 and the second laminate 40 with a metal material 34; arranging the first laminate 30 and the second laminate 40 such that a first direction, which is the stacking direction of the first laminate 30, and a second direction, which is the stacking direction of the second laminate 40, intersect with each other; bonding the phosphor 10 to the first laminate 30 via the bonding material 11a; and bonding the thermally conductive substrate 50 to the second laminate 40 via the bonding material 11b.

[0079] According to this method, the first laminate 30 and the second laminate 40 are arranged so that the first direction, which is the stacking direction of the first laminate 30, and the second direction, which is the stacking direction of the second laminate 40, intersect, so that heat from the phosphor 10 can be diffused in the intersecting first and second directions, and heat can be dissipated efficiently. Also, in the case of the phosphor 10, it is possible to suppress thermal decay, and it is possible to suppress a decrease in the light conversion efficiency of the phosphor 10.

[0080] In addition, the step of forming the first laminate 30 and the second laminate 40 preferably involves laminating the graphite layers 31 via the metal material 34, and applying pressure and heat to form the first laminate 30 and the second laminate 40. According to this method, since pressure and heat are applied, it is possible to sinter the first laminate 30 and the second laminate 40, and the adhesion between the first laminate 30 and the second laminate 40 can be improved.

[0081] Moreover, in the step of surface-modifying with metal material 34, it is preferable to surface-modify the portions including the cut surfaces of first laminate 30 and second laminate 40 with metal material 34. According to this method, the portions including the cut surfaces are further surface-modified with metal material 34, so that it is possible to prevent graphite layer 31 from being destroyed from the cut surfaces.

[0082] Next, the configuration of a heat conducting structure 200 according to a second embodiment will be described with reference to FIGS.

[0083] 12, the heat conducting structure 200 of the second embodiment differs from the heat conducting structure 100 of the first embodiment in that the size of the first laminate 230 in plan view is reduced. The other configurations are generally similar. Therefore, in the second embodiment, the parts that differ from the first embodiment will be described in detail, and the description of the other overlapping parts will be omitted as appropriate.

[0084] The thermally conductive structure 200 of the second embodiment includes a phosphor 10, a laminated structure 220, a thermally conductive substrate 50, and a heat sink 60. The laminated structure 220 has a first laminate 230 arranged on the phosphor 10 side, and a second laminate 40 arranged on the thermally conductive substrate 50 side. The second laminate 40 has the same configuration as in the first embodiment.

[0085] First laminate 230 has a width W2 in a first direction, which is the direction in which graphite layers 31 are laminated, which differs from the width of first laminate 30 of the first embodiment. Specifically, width W2 in the first direction of first laminate 230 is equal to or larger than width W1 in the first direction of phosphor 10 and is smaller than width W3 in the first direction of second laminate 40.

[0086] 12 and 13, the size of the phosphor 10 in a plan view is, for example, 4 mm×4 mm, as described above. The size of the first stack 230 in a plan view is, for example, 4 mm×8 mm. That is, the width W2 is small, at 4 mm. The size of the second stack 40 in a plan view is, for example, 8 mm×8 mm, as described above.

[0087] As described above, although the size of first laminate 230 is different from that of second laminate 40, heat generated in phosphor 10 is transferred with high thermal conductivity along the surface direction of graphite layer 31 (i.e., the second direction). Therefore, heat is not easily transferred in the first direction of first laminate 230, in other words, because first laminate 230 has anisotropy, even if width W2 in the first direction is reduced, heat can be diffused substantially in the same manner as in the first embodiment. In addition, since the size of first laminate 230 can be reduced, the amount of graphite sheet 32 ​​used as material can be reduced.

[0088] As described above, according to the second embodiment of the thermal conduction structure 200, the laminated structure 220 has the first laminate 230 and the phosphor 10 bonded to each other, and the side of the first laminate 230 opposite the phosphor 10 is bonded to the second laminate 40, and the width W2 in the first direction of the first laminate 230 is greater than or equal to the width W1 in the first direction of the phosphor 10 and is smaller than the width W3 in the first direction of the second laminate 40.

[0089] According to this configuration, the width W2 in the first direction of the first laminate 230 is smaller than the width W3 in the first direction of the second laminate 40, so that it is possible to reduce the amount of material of the first laminate 230 in the first direction, which is the direction in which heat is difficult to dissipate. Therefore, it is possible to reduce the cost while maintaining the heat dissipation efficiency.

[0090] Modifications of the above embodiment will now be described.

[0091] As described above, the pitch widths of the graphite layers 31 in the first laminate 30 and the second laminate 40 are not limited to being the same, and may be different, for example. Specifically, the pitch width of the graphite layers 31 of the first laminate 30 arranged on the phosphor 10 side, which is the heat source, is made smaller than the pitch width of the graphite layers 31 of the second laminate 40. In other words, the pitch width closer to the heat source is made dense, and the pitch width farther away is made sparse. This can improve the strength of the second laminate 40.

[0092] Further, although the phosphor 10 has been described as an example of a heat source, the present invention is not limited to this. For example, the heat conducting structure 100 may be used for dissipating heat from a lamp or other light emitting body.

[0093] In addition, the method is not limited to forming a laminate precursor and then cutting it into individual pieces, and for example, graphite layers 31 each having a size that has already been individualized may be laminated to form first laminate 30. However, since multiple sintering steps are required, it is preferable to appropriately select the number of steps according to the required quantity.

[0094] Furthermore, the first laminate 30 and the second laminate 40 are not limited to being formed from separate laminate precursors, and the first laminate 30 and the second laminate 40 may be cut out from the same laminate precursor.

[0095] The first laminate 30 and the second laminate 40 may be, for example, a laminate in which flaked graphite powder is joined to improve thermal conductivity, or in which the crystal direction or fiber direction of CNTs (carbon nanotubes) is aligned. They may also be combined with the graphite sheet 32 ​​to be used or may be compounded to form a laminate.

[0096] Although the graphite sheet 32 ​​is described as being surface-modified with the metal material 33 by copper plating, the present invention is not limited thereto, and metal materials with high thermal conductivity such as gold (Au) and Ag (silver) may be used. When the surface is modified by sputtering, a thin film of titanium (Ti), titanium tungsten (TiW), titanium nitride (TiN), or the like may be used as the underlying metal to improve adhesion. Prior to sputtering, the surface may be roughened by reverse sputtering with argon (Ar) atoms to further improve adhesion. [Explanation of symbols]

[0097] 10... phosphor as heat source, 11a, 11b, 11c... bonding material, 20... laminated structure, 30... first laminate, 31... graphite layer, 32... graphite sheet, 33, 34... metal material, 40... second laminate, 50... thermally conductive substrate, 60... heat sink, 100, 200... thermally conductive structure, 220... laminated structure, 230... first laminate, 514, 515... glass plate, 520 ...first light source, 521...second light source, 522...wavelength conversion section, 524, 525...reflective layer, 526...silver mirror, 527...pickup lens, 671...light source, 672...light-collecting optical system, 672a...first lens, 672b...second lens, 673...scattering plate, 674...collimating optical system, 674a...first lens, 674b...second lens, 720...first lens array, 720a...second 1 lens, 730... second lens array, 730a... second lens, 740... polarization conversion element, 750... superimposing lens, 1000... projector, 1010B, 1010G, 1010R... field lenses, 1200... illumination device, 1210... first light source device, 1220... second light source device, 1230... dichroic mirror, 1240... uniform illumination optical system, 1300... color separation Optical system, 1400B, 1400G, 1400R...light modulation device, 1500...light combining optical system, 1600...projection optical system, 1700a...first dichroic mirror, 1700b...second dichroic mirror, 1800a...first reflecting mirror, 1800b...second reflecting mirror, 1800c...third reflecting mirror, 1900a...first relay lens, 1900b...second relay lens.

Claims

1. A laminated structure formed by laminating graphite layers each including a graphite sheet surface-modified with a metal material, A heat source; a first laminate and a second laminate joined to the heat source, in which the graphite layer and the metal material are laminated; Equipped with The first stack and the second stack are stacked such that a first direction, which is a stacking direction of the first stack, and a second direction, which is a stacking direction of the second stack, cross each other; the graphite sheet has a surface, including an end face, modified with the metal material; The laminated structure includes the first laminate and the heat source joined together, and the second laminate joined to a side of the first laminate opposite to the heat source, A laminated structure, characterized in that the width of the first stack in the first direction is greater than or equal to the width of the heat source in the first direction and smaller than the width of the second stack in the first direction.

2. A thermally conductive structure as claimed in claim 1, A thermally conductive structure, comprising: a thermally conductive substrate joined to the laminated structure on the opposite side to the heat source.

3. 3. The thermally conductive structure according to claim 2, A thermal conductive structure, comprising: a heat sink joined to the thermal conductive substrate on the opposite side to the laminated structure.

Images