Electronic device manufacturing method

Abstract

To provide a manufacturing method for an electronic device that can easily and highly reliably seal an electronic component even when a conductor connected to the electronic component is drawn out from the inside of a casing.SOLUTION: An electronic component 3 is arranged in a housing space 23 of a first member 21 containing a thermoplastic resin, and a conductor 4 connected to the electronic component 3 is drawn out from the housing space 23 through an opening 24. A second member 22 containing a thermoplastic resin is stacked on the first member 21 so as to close the opening 24; the conductor 4 is sandwiched between the first member 21 and the second member 22; and at least one of a thermoplastic resin coating 6 and a thermosetting adhesive 5 is interposed between each of the first member 21 and the second member 22 and the conductor 4. The first member 21 and the second member 22 are joined by laser welding to produce the casing 2, and the conductor 4 is bonded to each of the first member 21 and the second member 22 via at least one of the resin coating 6 and the cured adhesive 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing an electronic device, and more particularly to a method for manufacturing an electronic device including a housing and electronic components housed in the housing. [Background technology]

[0002] Patent Document 1 describes that laser welding is being considered as a method for joining molded resin parts for sealing electrical circuits in electronic control components such as engine control units (ECUs) and sensors, and as a method for achieving airtightness without resin potting. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-24396 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a method for manufacturing an electronic device that includes a housing and an electronic component housed in the housing, and that can easily and reliably seal the electronic component with the housing even if a conductor connected to the electronic component is pulled out from inside the housing to outside the housing. [Means for solving the problem]

[0005] A method for manufacturing an electronic device according to one aspect of the present disclosure includes preparing a first member containing a thermoplastic resin, having an internal storage space and an opening connecting the interior and exterior of the storage space, a second member containing a thermoplastic resin, an electronic component, and a conductor connected to the electronic component. The electronic component is placed in the storage space of the first member, and the conductor connected to the electronic component is extended from the storage space to the exterior through the opening. The second member is placed on the first member so as to close the opening, sandwiching the conductor between the first member and the second member, and interposing at least one of a thermoplastic resin coating covering the conductor and a thermosetting adhesive between the first member, the second member, and the conductor. A laser beam is irradiated toward the boundary between the first member and the second member to laser weld the first member and the second member to form a housing, and the first member and the second member are bonded to the conductor via at least one of the resin coating and the cured adhesive. [Effects of the Invention]

[0006] According to one aspect of the present disclosure, when manufacturing an electronic device comprising a housing and an electronic component housed in the housing, the electronic component can be easily and reliably sealed by the housing even if a conductor connected to the electronic component is pulled from inside the housing to outside the housing. [Brief explanation of the drawings]

[0007] [Figure 1] 1A is a schematic cross-sectional view of an example of an embodiment of the present disclosure, and FIG. 1B is a schematic cross-sectional view of another example of an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic perspective view of an embodiment of the present disclosure. [Figure 3] FIG. 3 is a schematic perspective view of an embodiment of the present disclosure. [Figure 4] FIG. 4 is a schematic cross-sectional view of a portion of an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] 1. The process leading to the completion of this disclosure First, an outline of the process by which the inventors have completed the present disclosure will be described.

[0009] Products with complex shapes, such as the housings of electronic devices such as engine control units (ECUs) and sensors, are resin molded products formed by injection molding, etc. Electronic components such as electronic circuit boards are enclosed inside the housings.

[0010] In order to encapsulate electronic components, methods such as potting are used to fill the housing with resin to seal the electronic components. However, since the potting method increases the weight of the housing due to the potting material, methods other than potting to encapsulate electronic components are being considered in order to reduce weight, etc.

[0011] For example, a housing may be produced by joining two resin molded parts using ultrasonic welding or hot plate welding, and electronic components may be enclosed within the housing. However, according to the inventor's research, these methods have problems in that the electronic components may be damaged by vibration or heat, and that post-processing may be required due to the generation of wear powder or burrs.

[0012] Furthermore, as described in Patent Document 1, laser welding has been investigated as a method for joining molded parts made of thermoplastic resin. In this method, the resin molded parts are melted and joined together by irradiating the boundary between them with a laser beam. The use of laser welding can solve the problems that arise when ultrasonic welding or hot plate welding is used.

[0013] However, the inventors discovered that when manufacturing an electronic device including a housing and electronic components housed in the housing, it is difficult to ensure airtightness of the housing when conductors such as wire harnesses and bus bars connected to the electronic components are pulled from inside the housing to outside the housing. This is because, when two resin molded products are combined and joined by a welding method, if a conductor is sandwiched between the two resin molded products, it is difficult to ensure airtightness between the conductor and the resin molded products. Furthermore, if the conductor passes through a location on the housing other than where the two resin molded products are joined, the manufacturing process for the resin molded products becomes complicated.

[0014] Therefore, the inventors have completed the present disclosure in order to provide a method for manufacturing an electronic device that includes a housing and an electronic component housed in the housing, and that can easily and reliably seal the electronic component with the housing even if the conductor connected to the electronic component is pulled out from inside the housing to outside the housing.

[0015] Although the present disclosure has been completed through the above process, the above process does not limit the scope of application of the method for manufacturing an electronic device according to the present disclosure.

[0016] 2. Overview An embodiment of the present disclosure is illustrated in FIGS. 1A, 1B, 2, and 3. In a manufacturing method of an electronic device 1 according to an embodiment of the present disclosure, a first member 21 containing a thermoplastic resin, having an internal storage space 23, and having an opening 24 connecting the inside and outside of the storage space 23, a second member 22 containing a thermoplastic resin, an electronic component 3, and a conductor 4 connected to the electronic component 3 are prepared. The electronic component 3 is placed in the storage space 23 of the first member 21, and the conductor 4 connected to the electronic component 3 is extended from the storage space 23 to the outside of the storage space 23 through the opening 24 (see FIG. 2). The second member 22 is placed on the first member 21 so as to close the opening 24, and the conductor 4 is sandwiched between the first member 21 and the second member 22. At least one of a thermoplastic resin coating 6 covering the conductor 4 and a thermosetting adhesive 5 is interposed between the first member 21, the second member 22, and the conductor 4. By irradiating the boundary between the first member 21 and the second member 22 with laser light 7, the first member 21 and the second member 22 are joined by laser welding to produce the housing 2, and the first member 21 and the second member 22 are each bonded to the conductor 4 via at least one of the resin coating 6 and the cured product of the adhesive 5 (see FIG. 3). Note that FIG. 1A shows an example in which the adhesive 5 is used, and FIG. 1B shows an example in which the resin coating 6 is used.

[0017] According to this embodiment, the first member 21 and the second member 22 are joined by laser welding, and the conductor 4 is bonded to each of the first member 21 and the second member 22 by at least one of the resin coating 6 and the cured product of the adhesive 5. This ensures airtightness of the housing 2. Therefore, the electronic component 3 can be sealed within the housing 2. Furthermore, during the manufacture of the electronic device 1, by irradiating the boundary between the first member 21 and the second member 22 with laser beam 7 for laser welding, at least one of the thermoplastic resin coating 6 covering the conductor 4 and the thermosetting adhesive 5 can be heated. This allows the conductor 4 to be bonded to each of the first member 21 and the second member 22 by at least one of the resin coating 6 and the cured product of the adhesive 5. Therefore, even if the conductor 4 connected to the electronic component 3 is pulled out from inside the housing 2 to the outside of the housing 2, the electronic component 3 can be easily and reliably sealed within the housing 2.

[0018] Therefore, even if the electronic component 3 is susceptible to damage by moisture, the intrusion of moisture into the housing 2 from around the conductor 4 in the housing 2 is suppressed, making the electronic component 3 less susceptible to damage. In other words, the moisture resistance reliability of the electronic device 1 can be improved.

[0019] Furthermore, in this embodiment, the electronic component 3 can be easily and reliably sealed by the housing 2 without filling the interior of the housing 2 (inside the housing space 23) with a sealing material such as a potting material. Therefore, an increase in weight due to the potting material can be suppressed. Note that in this embodiment, for the purpose of further improving the sealing performance, a sealing material such as a potting material may be filled inside the housing 2 (inside the housing space 23).

[0020] 2. First member and second member The first member 21 and the second member 22 will be described in detail.

[0021] As described above, the first member 21 has an internal storage space 23 and an opening 24 that connects the inside of the storage space 23 with the outside. The second member 22 has a shape and dimensions that allow it to be placed on the first member 21 so as to cover the opening 24 of the first member 21. By placing the second member 22 on the first member 21 as described above, the first member 21 and the second member 22 are combined to form the housing 2.

[0022] The first member 21 and the second member 22 are joined by laser welding. In this case, for example, the first member 21 functions as a laser light absorbing material, and the second member 22 functions as a laser light transmitting material.

[0023] As described above, each of the first member 21 and the second member 22 contains a thermoplastic resin. For example, each of the first member 21 and the second member 22 is produced by molding a molding resin composition containing a thermoplastic resin by a method such as injection molding.

[0024] The thermoplastic resin contained in the first member 21 and the thermoplastic resin contained in the second member 22 each contain at least one selected from the group consisting of, for example, polyester, polyamide, and polycarbonate. In this case, the first member 21 and the second member 22 can be joined by laser welding, and good laser light transmittance can be imparted to the second member 22, which is a laser light transmissive material. When the thermoplastic resin contained in the first member 21 and the thermoplastic resin contained in the second member 22 each contain polyester, the first member 21 and the second member 22 can be particularly easily joined by laser welding, and the housing 2 can have good heat resistance. However, the thermoplastic resin is not limited to the above.

[0025] The molding resin compositions used to produce each of the first member 21 and the second member 22 will be described.

[0026] As described above, the molding resin composition contains a thermoplastic resin, and the thermoplastic resin contains, for example, at least one selected from the group consisting of polyester, polyamide, and polycarbonate.

[0027] When the thermoplastic resin contains a polyester, the polyester may contain a crystalline component, or may contain a non-crystalline (amorphous) component.

[0028] The polyester preferably contains at least one selected from the group consisting of polybutylene terephthalate resin, polyethylene terephthalate resin, and polyethylene naphthalate resin. The polyester more preferably contains polybutylene terephthalate resin. When the molding resin composition contains polybutylene terephthalate resin, the first member 21 and the second member 22 can be particularly easily joined by laser welding, and the housing 2 can have particularly good heat resistance.

[0029] Polybutylene terephthalate resins are synthesized by copolymerizing monomer components including, for example, terephthalic acid and 1,4-butanediol. The monomer components may contain only terephthalic acid and 1,4-butanediol. The monomer components may further contain at least one monomer selected from the group consisting of appropriate polycarboxylic acids and polyols. The polycarboxylic acids may include at least one compound selected from the group consisting of isophthalic acid, naphthalenedicarboxylic acid, adipic acid, sebacic acid, dodecanedioic acid, and oxalic acid. The polyols may include at least one compound selected from the group consisting of ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, polyethylene glycol, poly-1,3-propylene glycol, and polytetramethylene glycol.

[0030] The polybutylene terephthalate resin may include at least one selected from the group consisting of, for example, polybutylene terephthalate, polybutylene terephthalate isophthalate copolymer, polybutylene terephthalate adipate copolymer, polybutylene terephthalate sebacate copolymer, polybutylene terephthalate decanedicarboxylate copolymer, polybutylene terephthalate naphthalate copolymer, and polyethylene butylene terephthalate.

[0031] When the molding resin composition contains a polyester, the molding resin composition may further contain an epoxy resin. The epoxy resin can impart hydrolysis resistance to the molding resin composition, as well as to the first member 21 and the second member 22, by reacting with the polyester. The epoxy resin can contain at least one selected from the group consisting of bisphenol epoxy resins, novolac epoxy resins, alicyclic epoxy resins, glycidyl ethers, glycidyl esters, glycidyl amines, and heterocyclic epoxy resins. The bisphenol epoxy resin can contain at least one selected from the group consisting of bisphenol A epoxy resins, bisphenol F epoxy resins, and bisphenol S epoxy resins. The novolac epoxy resin can contain at least one selected from the group consisting of phenol novolac epoxy resins, cresol novolac epoxy resins such as o-cresol novolac epoxy resins, bisphenol A novolac epoxy resins, and dicyclopentadiene novolac epoxy resins. The alicyclic epoxy resin may contain at least one selected from the group consisting of, for example, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6-methylcyclohexanecarboxylate, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, and 1-epoxyethyl-3,4-epoxycyclohexane. The glycidyl ester may contain at least one selected from the group consisting of, for example, phthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, and dimer acid glycidyl ester. The glycidyl amine may contain at least one selected from the group consisting of, for example, tetraglycidyldiaminodiphenylmethane, triglycidyl p-aminophenol, and N,N-diglycidylaniline. The heterocyclic epoxy resin may contain at least one selected from the group consisting of, for example, 1,3-diglycidyl-5,5-dimethylhydantoin and triglycidyl isocyanurate.

[0032] The epoxy resin preferably contains a cresol novolac epoxy resin, and more preferably an o-cresol novolac epoxy resin, which can further improve the hydrolysis resistance of the first member 21 and the second member 22.

[0033] The percentage of the epoxy resin relative to the total solid content of the molding resin composition is preferably 0.5% by mass or more and 7% by mass or less, more preferably 1% by mass or more, more preferably 5% by mass or less, and even more preferably 2% by mass or less.

[0034] The molding resin composition may contain an inorganic filler. The inorganic filler can improve the mechanical strength of the first member 21 and the second member 22. The inorganic filler may contain at least one of talc, aluminum hydroxide, alumina, silica, mica, clay, wollastonite, titanium oxide, barium titanate, silicon nitride, aluminum nitride, boron nitride, silicon carbide, zirconium carbide, and magnesium hydroxide. The percentage of the inorganic filler relative to the total solid content of the molding resin composition is preferably 0.5% by mass or more and 5% by mass or less. In this case, the mechanical strength and other properties of the first member 21 and the second member 22 can be improved. Furthermore, particularly in the molding resin composition for producing the second member 22, when the percentage of the inorganic filler is 0.5% by mass or more, the laser beam transmittance of the second member 22 can be maintained at a good level. The percentage of the inorganic filler is more preferably 1% by mass or more, and even more preferably 2% by mass or more. Furthermore, the percentage of the inorganic filler is more preferably 4% by mass or less.

[0035] The molding resin composition may contain glass flakes. The glass flakes can suppress moisture penetration through the first member 21 and the second member 22. Furthermore, when the first member 21 and the second member 22 are joined by laser welding, the glass flakes scatter the laser light 7, thereby making it less likely that damage such as carbonization (resin discoloration) will occur at the joint between the first member 21 and the second member 22. When the molding resin composition contains glass flakes, the percentage of the glass flakes is preferably 10% by mass or more and 40% by mass or less with respect to the total solid content of the molding resin composition. It is more preferable that the percentage of the glass flakes is 35% by mass or less.

[0036] The molding resin composition may contain glass fibers. The glass fibers can improve the mechanical strength of the first member 21 and the second member 22. When the molding resin composition contains glass fibers, the percentage of the glass fibers relative to the total solid content of the molding resin composition is preferably 10% by mass or more and 20% by mass or less. In this case, the mechanical strength of the first member 21 and the second member 22 can be further increased.

[0037] The molding resin composition may contain components other than those described above, such as additives, as long as they do not deviate from the objectives of the present disclosure. The additives may include, for example, at least one selected from the group consisting of a mold release agent, a thickener, an antifoaming agent, a heat stabilizer, an antioxidant, a lubricant, and an ultraviolet stabilizer. Examples of mold release agents include fatty acids such as stearic acid, montanic acid, and myristic acid; aliphatic acid metal salts such as zinc stearate and calcium stearate; surfactants such as phosphate esters; carnauba wax; and polyethylene wax. Examples of thickeners include oxides or hydroxides of at least one divalent metal selected from the group consisting of magnesium, calcium, zinc, and strontium, or acrylic polymers. Examples of antifoaming agents include silicone-based antifoaming agents.

[0038] Furthermore, the molding resin composition for producing the first member 21, which is particularly a laser-beam-absorbing material, preferably contains a material having laser-beam-absorbing properties, and particularly preferably contains carbon. That is, the first member 21 preferably contains a material having laser-beam-absorbing properties, and particularly preferably contains carbon. In this case, when the first member 21 and the second member 22 are joined by laser welding, the first member 21 is likely to absorb the laser beam 7 and generate heat, thereby enabling the first member 21 and the second member 22 to be joined efficiently. Note that, as long as the first member 21 can absorb the laser beam 7 and generate heat, the molding resin composition for producing the first member 21 and the first member 21 do not need to contain a material having laser-beam-absorbing properties, such as carbon.

[0039] The percentage of carbon in the molding resin composition relative to the total solid content of the molding resin composition used to produce the first member 21 is preferably 0.1% by mass or more and 5% by mass or less. This percentage is more preferably 0.2% by mass or more. Furthermore, this percentage is more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.

[0040] The percentage of carbon in the first member 21 relative to the total mass of the first member 21 is preferably 0.1% by mass or more and 5% by mass or less. This percentage is more preferably 0.2% by mass or more. This percentage is more preferably 1% by mass or less, and even more preferably 0.5% by mass or less.

[0041] When preparing a molding resin composition, for example, the raw materials for the molding resin composition are mixed and then heated and kneaded. When the raw materials contain at least one of glass flakes and glass fiber, it is preferable to first heat the mixture obtained by mixing raw materials other than the glass flakes and glass fiber, then add at least one of the glass flakes and glass fiber to this mixture, and then knead them. The product (kneaded product) obtained by heating and kneading the raw materials is cooled to solidify, and further molded into pellets as necessary, to obtain a molding resin composition.

[0042] The first member 21 and the second member 22 can each be produced by molding the molding resin composition by an appropriate method such as injection molding.

[0043] 3. Electronic components and conductors The electronic component 3 is, for example, an electronic substrate obtained by mounting components such as semiconductor chips on a wiring board, but is not limited to this. The electronic component 3 is sealed or coated, for example, to improve moisture resistance. Examples of the electronic component 3 include engine control units or sensors sealed with resins such as silicone resin, urethane resin, or epoxy resin, various motherboards sealed or coated with resins such as silicone resin, urethane resin, or epoxy resin, and film capacitors sealed with resins such as epoxy resin.

[0044] The conductor 4 connected to the electronic component 3 is, for example, an external connection terminal such as a wire harness or a bus bar, but is not limited to these. The conductor 4 may be made of any conductive material. The conductor 4 may be made of a metal such as copper or aluminum. The conductor 4 may be made of an alloy. The conductor 4 may be metal-plated. One conductor 4 may be connected to the electronic component 3, but typically multiple conductors 4 are connected to the electronic component 3.

[0045] 4. Electronic device manufacturing process First, as shown in Fig. 2, an electronic component 3 is placed in the accommodation space 23 of the first member 21. The conductor 4 connected to the electronic component 3 is drawn from the accommodation space 23 to the outside of the accommodation space 23 through the opening 24. Next, the second member 22 is placed on top of the first member 21 so as to close the opening 24. For example, a flat surface (hereinafter referred to as a bonding surface 25) surrounding the opening 24 of the first member 21 is formed around the periphery of the opening 24, and by placing the second member 22 on this bonding surface 25, the second member 22 is placed on top of the first member 21, and the opening 24 is closed by the second member 22.

[0046] In addition, in a state where the second member 22 is placed on the first member 21 as described above, the conductor 4 is sandwiched between the first member 21 and the second member 22.

[0047] Furthermore, with the conductor 4 sandwiched between the first member 21 and the second member 22, at least one of a thermoplastic resin coating 6 covering the conductor 4 and a thermosetting adhesive 5 is interposed between each of the first member 21 and the second member 22 and the conductor 4.

[0048] When a thermoplastic resin coating 6 is used, the entire conductor 4 may be covered with the resin coating 6, or only the portion of the conductor 4 sandwiched between the first member 21 and the second member 22 may be covered with the resin coating 6. When an adhesive 5 is used, the adhesive 5 is disposed around the portion of the conductor 4 sandwiched between the first member 21 and the second member 22, for example, and when the conductor 4 is covered with the resin coating 6, the adhesive 5 is disposed around this resin coating 6.

[0049] Next, as shown in FIG. 3 , laser light 7 is irradiated toward the boundary between the first member 21 and the second member 22, thereby joining the first member 21 and the second member 22 by laser welding, thereby producing the housing 2. The laser light 7 is irradiated so that it passes through the second member 22, which is, for example, a transparent material, and then reaches the first member 21, which is an absorbent material, at the boundary between the first member 21 and the second member 22, i.e., the joining surface 25. As a result, the first member 21 absorbs the laser light 7 and generates heat, which causes the first member 21 and the second member 22 to melt around the boundary between the first member 21 and the second member 22 and then solidify, thereby joining the first member 21 and the second member 22. By moving the irradiation position of the laser light 7, the laser light 7 is irradiated over the entire boundary between the first member 21 and the second member 22, thereby joining the first member 21 and the second member 22 over the entire boundary between the first member 21 and the second member 22. In this way, the housing 2 is produced.

[0050] In this process of joining the first member 21 and the second member 22 by laser welding, when the laser beam 7 is irradiated around the portion of the conductor 4 sandwiched between the first member 21 and the second member 22, if a resin coating 6 is used, the resin coating 6 is heated, melted, and then solidified, thereby bonding the conductor 4 to each of the first member 21 and the second member 22 by the resin coating 6. If an adhesive 5 is used, the adhesive 5 is heated and hardened, thereby bonding the conductor 4 to each of the first member 21 and the second member 22 by the hardened product of the adhesive 5. If the resin coating 6 and the adhesive 5 are used together, the conductor 4 is bonded to each of the first member 21 and the second member 22 by the hardened product of the resin coating 6 and the adhesive 5 (see FIGS. 1A and 1B). This brings the conductor 4 into close contact with each of the first member 21 and the second member 22, thereby improving the airtightness of the housing 2. Therefore, even if the conductor 4 connected to the electronic component 3 is drawn from inside the housing 2 to the outside of the housing 2, the electronic component 3 can be sealed by the housing 2 easily and with high reliability.

[0051] In this embodiment, the thickness of the portion of the conductor 4 sandwiched between the first member 21 and the second member 22 in the direction from the first member 21 to the second member 22 is preferably 2 mm or less. In this case, the conductor 4 is less likely to impede heat transfer, and therefore the heat generated when joining the first member 21 and the second member 22 by laser welding is more easily transferred to the resin coating 6 and the adhesive 5, allowing the resin coating 6 to melt efficiently and the adhesive 5 to harden efficiently. The thickness of the conductor 4 is, for example, 5 μm or more, but is not limited to this. When the conductor 4 is covered with the resin coating 6, the thickness of the conductor 4 including the resin coating 6 is preferably within the above-mentioned range.

[0052] Furthermore, in the portion of the conductor 4 sandwiched between the first member 21 and the second member 22, the dimension (width) of the conductor 4 in the direction along the edge of the opening 24 is preferably 30 mm or less. In this case, the portion of the first member 21 where the laser light 7 is blocked by the conductor 4 can be prevented from becoming excessively large, thereby suppressing a decrease in the efficiency of laser welding by the conductor 4. It is more preferable that this width be 20 mm or less. The width of the conductor 4 is, for example, 5 μm or more, but is not limited to this. Note that, when the conductor 4 is covered with a resin coating 6, it is preferable that the width of the conductor 4 including the resin coating 6 (the width of the combination of the conductor 4 and the resin coating 6) be in the above-mentioned range.

[0053] In this embodiment, as shown in FIG. 4 , at least one of the first member 21 and the second member 22 may have a recess 8 at a location where the conductor 4 is disposed when the conductor 4 is sandwiched between the first member 21 and the second member 22. The recess 8 in the first member 21 is, for example, a groove-shaped recess that opens toward the conductor 4 and connects the accommodation space 23 side to the opposite side of the accommodation space 23. The recess 8 in the second member 22 is, for example, a groove-shaped recess that opens toward the conductor 4 and connects the accommodation space 23 side to the opposite side of the accommodation space 23. In this case, since at least a portion of the conductor 4 fits within the recess 8, even when the conductor 4 is sandwiched between the first member 21 and the second member 22, a gap between the first member 21 and the second member 22 is unlikely to occur or the gap between the first member 21 and the second member 22 can be reduced. Therefore, the processing efficiency when joining the first member 21 and the second member 22 by laser welding can be improved, and the hermeticity of the housing 2 can be particularly improved.

[0054] The dimensions of the recess 8 are appropriately set so that no gap occurs between the first member 21 and the second member 22 joined by laser welding, but the depth dimension of the recess 8 is preferably smaller than the thickness of the conductor 4, and for example, the sum of the depth dimension of the recess 8 in the first member 21 and the depth dimension of the recess 8 in the second member 22 (if only one of the first member 21 and the second member 22 has a recess 8, the depth dimension of that recess 8) is half the thickness of the conductor 4. Note that, if the conductor 4 is covered with a resin coating 6, the thickness of the conductor 4 here refers to the thickness of the conductor 4 alone plus the thickness of the resin coating 6.

[0055] It should be noted that if the sealing of the housing 2 can be ensured by joining the first member 21 and the second member 22 by laser welding, the recesses 8 do not need to be formed in the first member 21 and the second member 22.

[0056] In this embodiment, when the resin coating 6 is used, it is preferable that the resin coating 6 has a melting point lower than both the melting point of the first member 21 and the melting point of the second member 22. In this case, the resin coating 6 can be reliably melted by the heat generated in the process of joining the first member 21 and the second member 22 by laser welding. This makes it possible to more easily and reliably improve the airtightness of the housing 2. The melting points of the first member 21, the second member 22, and the resin coating 6 are measured by the method shown in the examples described below.

[0057] The thermoplastic resin contained in the resin coating 6 preferably contains at least one selected from the group consisting of polyvinyl chloride, polyester, and fluorine-containing resin. In this case, the resin coating 6 melts particularly easily when the first member 21 and the second member 22 are joined by laser welding, and therefore the resin coating 6 can particularly improve the airtightness of the housing 2. When the thermoplastic resin contains a fluorine-containing resin, the fluorine-containing resin contains at least one selected from the group consisting of, for example, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene-ethylene copolymer (ETFE), and the like.

[0058] It is particularly preferable if the thermoplastic resin contained in the resin coating 6 contains polyester. Polyester is environmentally friendly and has a moderately low melting point, so that the resin coating 6 can particularly improve the hermeticity of the housing 2.

[0059] In this embodiment, when adhesive 5 is used, it is preferable that adhesive 5 be a urethane-based thermosetting adhesive, a silicone-based thermosetting adhesive, an acrylic-based thermosetting adhesive, or an epoxy-based thermosetting adhesive. In this case, when joining first member 21 and second member 22 by laser welding, adhesive 5 can be sufficiently cured, and the cured product of adhesive 5 becomes less permeable to moisture. It is particularly preferable that adhesive 5 be an epoxy-based thermosetting adhesive. In this case, the cured product of adhesive 5 becomes particularly less permeable to moisture. It is also preferable that epoxy-based thermosetting adhesive contains at least one of amines and thiols. However, adhesive 5 is not limited to the above.

[0060] Regarding the irradiation conditions of the laser light 7 when joining the first member 21 and the second member 22 by laser welding, the wavelength of the laser light 7 is, for example, 880 nm or more and 1200 nm or less. The laser light 7 may be, for example, a YAG laser, an Nd:YAG laser, or a semiconductor laser, but is not limited to these. The output of the laser light 7 can be appropriately adjusted depending on the materials and thicknesses of the first member 21 and the second member 22 so that the first member 21 and the second member 22 are sufficiently joined. The output of the laser light 7 is, for example, preferably 9 W or more, and more preferably 20 W or more. Furthermore, to prevent the first member 21 and the second member 22 from being excessively heated and causing deformation or damage, the output of the laser light 7 is preferably 200 W or less, and more preferably 40 W or less.

[0061] The moving speed of the irradiation position of the laser light 7 can also be adjusted appropriately depending on the materials and thicknesses of the first member 21 and the second member 22 so that the first member 21 and the second member 22 are sufficiently joined. This moving speed is preferably 3000 mm / sec or less. In consideration of processing efficiency, this moving speed is preferably 10 mm / sec or more, and more preferably 100 mm / sec or more.

[0062] When joining the first member 21 and the second member 22 by laser welding, in order to sufficiently heat and melt the resin coating 6 and sufficiently heat and harden the adhesive 5, the moving speed of the irradiation position of the laser light 7 may be reduced when the irradiation position is moved at the position of the conductor 4 and its vicinity. The irradiation position of the laser light 7 may be moved back and forth at the position of the conductor 4 and its vicinity. When the irradiation position of the laser light 7 is at the position of the conductor 4 and its vicinity, the output of the laser light 7 may be increased.

[0063] The irradiation conditions of the laser light 7 are not limited to the above, and may be set so that the first member 21 and the second member 22 are sufficiently joined together.

[0064] When joining the first member 21 and the second member 22 by laser welding, the thickness of the portion of the second member 22 through which the laser light 7 passes is preferably 2 mm or less. In this case, excessive attenuation of the laser light 7 within the second member 22 is unlikely to occur, and therefore the efficiency of the laser welding can be maintained at a good level. In addition, this thickness is preferably 0.1 mm or more. In this case, the penetration of moisture through the housing 2 can be suppressed. [Example]

[0065] Specific examples of this embodiment will be presented below, but this embodiment is not limited to the following examples.

[0066] 1. First member and second member (1) Preparation of molding resin composition (second composition) for second member 40.0 parts by mass of polyester resin 1, 25.0 parts by mass of polyester resin 2, 1.0 part by mass of epoxy resin, and 4.0 parts by mass of inorganic filler were blended and mixed in a blender. 30.0 parts by mass of glass flakes were added to the resulting mixture, and the mixture was kneaded in a twin-screw extrusion kneader with a cylinder temperature of 260°C. The resulting product (kneaded product) was cooled in water and then cut into pellets of approximately 2 to 4 mm using a pelletizer, yielding pellets of a molding resin composition (hereinafter referred to as the second composition). -Polyester resin 1: Polybutylene terephthalate (PBT) resin (manufactured by Toray Industries, Inc., product name Toraycon PBT1200). -Polyester resin 2: Polyethylene terephthalate (PET) resin (manufactured by Kuraray Co., Ltd., product name Kurapet PETKL236R). -Epoxy resin: o-cresol novolac epoxy resin (epoxy equivalent 210g / eq.). -Inorganic filler: talc, Micron White #500S (L value 95) manufactured by Hayashi Co., Ltd. -Flake glass: Nippon Sheet Glass Co., Ltd., product name MEG160FY-M01. Micro Glass Fine Flake (registered trademark). E-glass. Average thickness t: 0.7 μm, average particle size a: 160 μm.

[0067] (2) Preparation of molding resin composition (first composition) for first member The first composition was prepared in the same manner as the second composition, except that 1% by mass of the resin material in the second composition was replaced with a masterbatch containing carbon black, where the amount of carbon black in this masterbatch was 33 parts by mass per 100 parts by mass of the masterbatch.

[0068] (3) Fabrication of the first and second members The first composition was dried in a thermostatic oven at 140°C for 4 hours. The first composition was then injection molded to produce a first member. The external dimensions of the first member were 76mm x 76mm x 32mm, and the dimensions of the storage space within the first member were 72mm x 72mm x 30mm.

[0069] The second composition was dried in a thermostatic oven at 140°C for 4 hours. The second composition was then injection molded to produce a second member having dimensions of 76mm x 76mm x 1mm.

[0070] In addition, in Examples 1-5, a groove-shaped recess with a rectangular cross section was formed on the joining surface of the first member, with the dimensions shown in Table 1. No recess was formed in the second member.

[0071] 2. Electronic components and conductors Conductor wiring made from copper foil was installed on a 70mm x 70mm x 2mm FR-4 equivalent board, and a semiconductor chip measuring 20mm x 20mm x 0.5mm was mounted in the center of the board. Silver paste was used as the die bond material, and the circuit and pads on the top surface of the semiconductor chip were formed from aluminum, with the pads and conductor wiring connected with aluminum wire. This produced an electronic component.

[0072] In Examples 1, 3, and 4, six harnesses were connected as conductors to the conductor wiring on the substrate of the electronic component. In Examples 2, 5, and the Comparative Example, two bus bars were connected as conductors to the conductor wiring on the substrate of the electronic component. The cross-sectional dimensions (thickness and width) of the conductor in each Example and Comparative Example are as shown in Table 1. In addition, in Examples 1, 3, and 4, the conductor was covered with a resin coating made of the material shown in Table 1, and the cross-sectional dimensions of the conductor shown in Table 1 do not include the resin coating.

[0073] 3. Electronic device manufacturing An electronic component was placed in the housing space of the first member, and a conductor connected to the electronic component was led out of the housing space through the opening of the first member. In Examples 1-5, the conductor was arranged to pass through the recess of the first member.

[0074] The second member was placed on the first member so as to close the opening of the first member with the second member, and the conductor was sandwiched between the first member and the second member. In Examples 2, 3, and 5, a thermosetting epoxy adhesive manufactured by Panasonic Corporation with the product number shown in Table 1 was applied around the conductor, thereby interposing the thermosetting epoxy adhesive between the conductor and each of the first member and the second member.

[0075] Using a galvano scanning laser processing machine (model number VL-W1500) manufactured by Panasonic Devices SUNX Co., Ltd., laser light with a wavelength of 655 nm and an output of 20 W was irradiated so that it would pass through the second member and then reach the joining surface of the first member, and the irradiation position of the laser light was moved at a speed of 100 mm / g, thereby joining the first member and the second member by laser welding. In this way, an electronic device was manufactured.

[0076] Furthermore, as Reference Example 1, an electronic device was prepared in which the second member was not joined to the first member in Example 2, and the housing was constructed only from the first member. Also, as Reference Example 2, an electronic device was prepared in which the second member was not joined to the first member in Example 2, and the inside of the first member was sealed with a potting material.

[0077] 4.Product weight The weight of the electronic device was measured using an electronic balance.

[0078] 5. Reliability Test While applying a voltage of 50V between the two conductors of the electronic device, the current value between the conductors (initial current value) was measured, and it was confirmed that the initial current value was between 4.5A and 5.5A.

[0079] Next, the electronic device was exposed to an atmosphere of 85° C. and 85% RH for 1000 hours with a voltage of 100 V applied between the two conductors in the electronic device.

[0080] Next, the current value between the two conductors of the electronic device was measured while applying a voltage of 50 V. As a result, if the absolute value of the difference between the obtained current value and the initial current value was within 20% of the initial current value, it was evaluated as "good," and if it exceeded 20%, it was evaluated as "poor."

[0081] [Table 1]

[0082] [Table 2] [Explanation of symbols]

[0083] 1. Electronic Devices 21 First member 22 Second member 23 Containment Space 24 aperture 3. Electronic Components 4 conductors 5. Adhesive 6 Resin coating 7. Laser light 8 recess

Claims

1. a first member including a thermoplastic resin, having an accommodation space therein, and having an opening that allows the interior of the accommodation space to communicate with the exterior; a second member including a thermoplastic resin; Electronic components and a conductor connected to the electronic component; The electronic component is disposed in the accommodation space of the first member, and the conductor connected to the electronic component is led out of the accommodation space through the opening; The second member is placed on the first member so as to close the opening, the conductor is sandwiched between the first member and the second member, and at least one of a thermoplastic resin coating covering the conductor and a thermosetting adhesive is interposed between each of the first member and the second member and the conductor; a housing is fabricated by joining the first member and the second member by laser welding the first member and the second member by irradiating a laser beam toward a boundary between the first member and the second member, and bonding the first member and the second member to the conductor via at least one of the resin coating and the cured product of the adhesive; A method for manufacturing electronic devices.

2. The thermoplastic resin contained in the first member and the thermoplastic resin contained in the second member each contain at least one selected from the group consisting of polyester, polyamide, and polycarbonate. The method for manufacturing an electronic device according to claim 1 .

3. The first member contains carbon. The method for manufacturing an electronic device according to claim 1 or 2.

4. Using the resin coating, The thermoplastic resin contained in the resin coating contains at least one selected from the group consisting of polyvinyl chloride, polyester, and fluorine-containing resin. The method for manufacturing the electronic device according to claim 1 .

5. Using the adhesive, The adhesive is a urethane-based thermosetting adhesive, a silicone-based thermosetting adhesive, an acrylic-based thermosetting adhesive, or an epoxy-based thermosetting adhesive. The method for manufacturing the electronic device according to claim 1 .

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