Surface mount component, surface mount structure, and method for producing surface mount component

Abstract

Provided is a surface mount component that is soldered onto a circuit board through a reflow step, said surface mount component comprising: a silicone molded body which includes a functional part and a base part; and a support member which is assembled so as to be integrated with the silicone molded body. The support member includes a frame part that has an opening through which the functional part is exposed, a first tab that extends from the outer side of the frame part and that is bent along the outer shape of the base part so as to grip and fix the base part, and the second tab that extends from the frame part to the outside of the outer shape of the silicone molded body so as not to overlap with the silicone molded body and that is to be soldered. The second tab is soldered onto a pad that is on the surface of the circuit board and that is electrically independent from the wiring pattern.

Description

Surface Mount Component, Surface Mount Structure, and Method for Manufacturing Surface Mount Component

[0001] The present invention relates to a surface mount component that is solder-bonded to a circuit board by a reflow process, which is a surface mount technology.

[0002] A reflow process is widely used to solder an electronic component to the surface of a circuit board. From the perspective of environmental protection, in the reflow process, a reflow process using lead-free solder that employs a temperature profile including a high-temperature zone has become the mainstream.

[0003] For example, an LED element may be surface-mounted on the surface of a circuit board. A resin lens may be adhered to the light-emitting surface of the LED element with an adhesive to adjust the light distribution of the light emitted by the LED element. When adhering a resin lens to the light-emitting surface of the LED element, the adhesion is often performed manually, which causes a problem of increased production costs. The reason for the manual operation is that it is difficult to automate due to the difficulty of aligning the light-emitting surface and the resin lens.

[0004] In order to solve such problems, for example, Patent Document 1 below discloses a vehicle lighting device including a circuit board provided with a wiring pattern, a light source mounted on the circuit board via a first solder so as to be electrically connected to the wiring pattern, and a lens member covering the light source, wherein the lens member is fixed to the circuit board by a second solder having the same composition as the first solder at a position where it is not electrically connected to the wiring pattern. And Patent Document 1 discloses integrally forming the metal part by insert molding a lens member covering the light source.

[0005] Further, Patent Document 2 below discloses a surface mount device having a silicone lens member having a lens part and a base part, and a solderable support connected to the base part for facilitating reflow mounting on a printed circuit board.

[0006] Japanese Patent Application Laid-Open No. 2023-30367 US Published Patent Application No. 2021 / 0048593

[0007] An example of a temperature profile used in a reflow process using lead-free solder is a profile that includes a preheating zone at a temperature of approximately 150°C to 180°C, followed by heating to a temperature of 250°C or higher, and then cooling. In such a temperature profile, the heating time in each zone is set based on the temperature of the metal terminals to be soldered on the mounted electronic components.

[0008] In surface mount devices such as those disclosed in Patent Documents 1 and 2, the metal part to be soldered is positioned on the back surface of the resin lens member so as to overlap it. In a reflow process using lead-free solder, because the resin lens member has low thermal conductivity, when the temperature of the metal part reaches a temperature sufficient to melt the lead-free solder, for example, 250°C or higher, the resin lens member also becomes hot. In this case, due to the difference in thermal expansion coefficients between the lens member and the metal part, there is a concern that only the lens member will expand significantly, causing cracks in the lens member, displacement from the intended bonding position, or delamination of the soldered metal part due to shear stress.

[0009] Furthermore, Patent Document 1 discloses a method of integrally molding a lens member covering a light source with a metal part by insert molding. When a lens member is integrally molded with a metal part by insert molding, the liquid material that forms the lens member may seep into the metal part and embed it. To prevent such problems, advanced mold design technology and sophisticated control of conditions such as mold temperature are required. In addition, if the lens member is a silicone molded body, there is a concern that the low molecular weight siloxane compounds contained in the silicone may adhere to the metal part, reducing the wettability between the metal part and the solder during the reflow process and causing mounting defects. In this case, measures such as adding a degreasing step to the metal part as a post-processing step are necessary. Also, if the lens member is a silicone molded body, pre-treatment is required to improve adhesion with the metal part.

[0010] Furthermore, Patent Document 2 discloses a surface mount device in which a solderable metal support is integrated with the base of a silicone lens member by assembly. With such a surface mount device, it is possible to manufacture a surface mount device without using insert molding. However, in the surface mount device disclosed in Patent Document 2, since the silicone lens member is placed on a metal support and fixed with a metal lip that is folded inward, there is a concern that the metal support and the silicone lens member may easily shift position when the surface mount device mounted on a circuit board is subjected to vibration. In particular, due to the reflow process and heat cycle, repeated thermal expansion and contraction of the silicone lens member may cause the inwardly folded lip to open, loosening the fixation and raising concerns that the silicone lens member may detach from the support.

[0011] The present invention aims to provide a surface mount component that includes a silicone molded body with a functional part such as a lens, which is surface mounted by soldering to a circuit board having a wiring pattern using a reflow process, wherein the silicone molded body is not heated to an excessive temperature during the reflow process, the functional part is less likely to be misaligned with respect to a metal support member, the alignment of the functional part with respect to the support member is excellent, and assembly is easy.

[0012] One aspect of the present invention is a surface mount component that is soldered to a circuit board by a reflow process, comprising a silicone molded body having a base and a functional part formed on a first surface of the base, and a metal support member integrated with the silicone molded body by assembly, wherein the support member has a frame and a plurality of first tabs and second tabs extending from the outside of the frame, the frame is positioned on the first surface with the functional part exposed through an opening it surrounds, the first tabs are tabs that fix the support member to the base, folded in a way that grasps the second surface which is the opposite surface of the first surface, and the second tabs are folded so as to extend outwards from the silicone molded body without overlapping it, the surface mount component [1].

[0013] With such a surface mount component [1], the second tab, which is soldered, is bent so as to extend outward from the outer shape of the silicone molded body so as not to overlap it. This allows the heat from the reflow oven to easily reach the second tab without being obstructed by the silicone molded body during the reflow process, resulting in a rapid temperature rise. As a result, the temperature of the silicone molded body is less likely to rise too high. Furthermore, the support member is positioned so as to expose the functional part through the opening in its frame and cover the first surface, making it easier to align the support member with respect to the functional part and suppressing misalignment. In addition, the first tab is bent while wrapping around the second surface, which is the opposite surface of the first surface, and the support member is fixed to the base, allowing the silicone molded body and the metal support member to be easily integrated and assembled.

[0014] Here, the functional part refers to a part that exhibits a physical or chemical function, such as an optical function like a lens, wavelength conversion, wavelength filter, or light guide, a protective function that covers and protects surface-mounted electronic components, or a connecting function that connects other members by a snap-fit ​​structure, and preferably a part that protrudes from the first surface of the base. The base is a flange-shaped or platform-shaped part of the silicone molded body for integrating the support member. Furthermore, "bent while wrapping around the second surface, which is the opposite surface of the first surface" means that the first tab is bent so as to wrap around the side of the base and the second surface, thereby fixing the support member to the base without looseness. Furthermore, "bent so that the second tab extends outward to the outside of the silicone molded body so as not to overlap with the silicone molded body" means that when viewed from above, the second tab is bent so as to extend outward to the outside of the silicone molded body so as not to overlap with the silicone molded body.

[0015] Furthermore, it is preferable that the surface mount component [1] is a surface mount component [2] in which the volume filling rate of the base in the portion of the part covered by the first tab that overlaps with the base when viewed from above is 40 to 80%. As will be described later, by thinning the thickness of the base of the part covered by the first tab, the volume filling rate of the base of the part covered by the first tab is made 40 to 80%, so that even if the part of the base covered by the first tab expands due to heat, the effect of the volume change of the base due to thermal expansion is mitigated, thereby preventing the first tab that grips the base from deforming due to stress caused by the expansion of the base and loosening the engagement.

[0016] Furthermore, in surface mount components [1] and [2], it is preferable that the support member [3] has a plurality of third tabs extending from the outside of the frame, and the third tabs are bent to follow the side of the base so that their tips face the side. Having such a plurality of third tabs in the support member allows the support member to be aligned along the side of the base when assembling the surface mount component. It is preferable that such a plurality of third tabs are formed to follow the side of the base at room temperature before manufacturing, in order to contribute to the horizontal alignment of the support member when assembling the surface mount component by fixing the support member to the base. It is also preferable that the plurality of third tabs are evenly arranged with respect to the center of the functional part, so that even if the silicone molded body expands due to heat and the third tabs try to deform, the stress applied to each third tab is balanced and displacement is suppressed.

[0017] Furthermore, in the case of surface mount components [1] to [3], it is preferable that the silicone molded body is a surface mount component [4] which is a silicone elastomer molded body. In such cases, when the silicone elastomer molded body undergoes thermal expansion, the stress due to the volume change is relieved by the elasticity of the elastomer. As a result, it is possible to suppress the occurrence of cracks, thermal deformation, and displacement due to the thermal expansion of the silicone molded body. In addition, it is possible to suppress the deformation of the first tab that grips the base due to stress caused by the expansion of the base, which can lead to loosening of the engagement.

[0018] Furthermore, in the case of surface mount components [4], it is preferable that the silicone elastomer molded body is a surface mount component [5] which is a molded body of silicone elastomer having a durometer type A hardness of 40 to 95 in accordance with JIS K 6253. In such cases, when the silicone elastomer molded body undergoes thermal expansion, the stress due to the volume change can be relieved, and the surface tackiness is appropriate, making it easier to mount using a pick-and-place machine.

[0019] Furthermore, in surface mount components [1] to [5], the functional part is preferably a surface mount component [6] which is an optical element that covers an LED element mounted on a circuit board and adjusts the light emitted by the LED element. Furthermore, in surface mount component [6], the optical element is preferably a surface mount component [7] which is a lens member that adjusts the light distribution of the light emitted by the LED element. In such cases, the light distribution of the light emitted by the mounted LED element can be adjusted simply by surface mounting the surface mount component to the circuit board in the reflow process. Furthermore, in surface mount components [1] to [5], the functional part is preferably a surface mount component [8] which is an optical element such as a wavelength conversion unit that covers an LED element mounted on a circuit board and contains a phosphor that is excited by the light emitted by the LED element. In such cases, it is preferable that the color of the light emitted by the mounted LED element can be adjusted simply by surface mounting the surface mount component to the circuit board in the reflow process.

[0020] Furthermore, in the case of surface mount components [6] to [8], it is preferable that the silicone molded body is a surface mount component [9] having a recess on its second surface for accommodating an LED element mounted on a circuit board, as this facilitates alignment between the surface mount component and the LED element.

[0021] Furthermore, in the surface mount component [6] or surface mount component [7], it is preferable that the LED element is a surface mount component

[10] which is a deep ultraviolet LED element that emits UV-C ultraviolet light in the wavelength range of 100 to 280 nm. In deep ultraviolet LED elements that emit UV-C ultraviolet light, because the energy of UV-C ultraviolet light is high, when an optical element is bonded with an adhesive, the adhesive layer may be damaged and the light extraction efficiency may decrease. By using the surface mount component described above, the optical element can be attached to the LED element without using an adhesive, thus resolving the problem of reduced light extraction efficiency.

[0022] Furthermore, in the case of surface mount components [1] to [5], it is preferable that the silicone molded body is a surface mount component

[11] having the shape of a male or female snap-fit ​​structure. In such cases, it is possible to connect it to other members having the shape of a male or female snap-fit ​​structure via a snap-fit ​​structure, and various members can be attached to the circuit board afterwards.

[0023] Another aspect of the present invention is a surface mount structure

[12] in which any of the above surface mount components are surface mounted on a circuit board.

[0024] Another aspect of the present invention is a method for manufacturing a surface mount component to be soldered to a circuit board by a reflow process, comprising the steps of: preparing a silicone molded body having a base and a functional part formed on a first surface of the base; and a frame and a metal support member having a plurality of first tabs, second tabs and third tabs extending from the outside of the frame, wherein when assembled, the first tab is a tab for fixing the support member to the base, which is bent while wrapping around the second surface which is the opposite surface of the first surface, and the second tab is silicone A method for manufacturing a surface mount component, comprising the steps of: preparing a metal support member, the tab being bent so as to extend outward from the silicone molded body without overlapping the molded body, and the third tab being bent along the side of the base so that its tip faces the side; exposing the functional part from an opening surrounded by the frame and positioning the frame on the first surface such that the third tab is along the side of the base; and fixing the support member to the base by bending the first tab while wrapping it around the second surface so as to grasp it. By such a manufacturing method, the above-described surface mount component can be manufactured.

[0025] According to the present invention, a surface mount component including a silicone molded body having a functional part such as a lens, which is surface mounted by soldering to a circuit board having a wiring pattern by a reflow process, can be provided that prevents the silicone molded body from being heated too high in the reflow process, prevents the functional part from being misaligned relative to a metal support member, has excellent alignment of the functional part with respect to the support member, and is easy to assemble.

[0026] This is a schematic perspective view of a surface mount component 10 of one embodiment. This is a schematic front view (and rear view) of the surface mount component 10. This is a schematic side view of the surface mount component 10. This is a schematic top view of the surface mount component 10. This is a schematic bottom view of the surface mount component 10. This is a schematic cross-sectional view illustrating how the first tabs 2B and 2C of the surface mount component 10 are bent while wrapping around the second surface P2 of the base 1B to grasp it, thereby fixing the support member 2 to the base 1B. This is a schematic cross-sectional view illustrating how the third tabs 2H and 2J of the surface mount component 10 are bent along the side surface P3 of the base 1B, so that their tips face the side surface P3, thereby aligning them. This is a partial schematic cross-sectional view illustrating a surface mount structure 100 in which the surface mount component 10 is surface-mounted on a circuit board 20. This is a partial schematic cross-sectional view illustrating a surface mount structure 110 in which a surface mount component 40 of one embodiment is surface-mounted on a circuit board 20. This is a partially schematic cross-sectional view illustrating surface mount structures 120 and 130, in which surface mount components 50 and 60 having a snap-fit ​​structure as functional parts are surface mounted on circuit boards 70 and 80, respectively, according to one embodiment.

[0027] The surface mount component of this embodiment is a surface mount component that is soldered to a circuit board having a wiring pattern by a reflow process, and includes a silicone molded body having a base and a functional part formed on the first surface of the base, and a metal support member integrated with the silicone molded body by assembly. The support member has a frame and a plurality of first tabs and second tabs extending from the outside of the frame. The frame is positioned on the first surface, exposing the functional part through an opening it surrounds. The first tabs are tabs that fix the support member to the base, folded while wrapping around the second surface, which is the opposite surface of the first surface. The second tabs extend to the outside of the silicone molded body so as not to overlap the silicone molded body, and are folded so as to be soldered to pads electrically independent of the wiring pattern on the surface of the circuit board.

[0028] Hereinafter, as a representative example, a surface mount component 10, which is soldered to a circuit board having a wiring pattern by a reflow process according to this embodiment, will be described in detail with reference to the drawings. This surface mount component 10 includes a lens member for controlling the light distribution of light emitted from an LED element as a functional part.

[0029] Figure 1 is a schematic perspective view of the surface mount component 10. Figure 2 is a schematic front or rear view of the surface mount component 10. Figure 3 is a schematic side view of the surface mount component 10. Note that the front and rear, as well as the left and right sides of the surface mount component 10, have the same shape. Figure 4 is a schematic top view of the surface mount component 10, and Figure 5 is a schematic bottom view of the surface mount component 10.

[0030] Referring to Figures 1 to 5, the surface mount component 10 includes a silicone molded body 1 having a base portion 1B and a lens portion 1A which is a functional portion formed on the first surface P1 of the base portion 1B, and a support member 2 which is integrated by being assembled with the silicone molded body 1. The lens portion 1A is transparent, and in each figure, the shape of the recess for housing the LED element is shown through the lens portion.

[0031] The support member 2 has a rectangular frame portion 2A with a circular opening H through which the functional lens portion 1A is inserted and exposed, and first tabs 2B, 2C, second tabs 2D, 2E, 2F, 2G, and third tabs 2H, 2I, 2J, 2K extending outward from the frame portion 2A.

[0032] The first tabs 2B and 2C are bent and wrapped around the second surface P2, which is the opposite surface to the first surface P1 on which the functional lens portion 1A is located, thereby fixing the support member 2 to the base portion 1B. The second tabs 2D, 2E, 2F, and 2G extend from the frame portion 2A to the outside of the silicone molded body 1 so as not to overlap with the silicone molded body 1. As will be described later, the second tabs 2D, 2E, 2F, and 2G are bent so as to be soldered to pads that are electrically independent from the wiring pattern on the surface of the circuit board.

[0033] Furthermore, the third tabs 2H, 2I, 2J, and 2K are bent to conform to the side surface P3 of the base 1B of the silicone molded body 1 when assembling the surface mount component 10 by integrating the silicone molded body 1 and the support member 2, and their tips are positioned to face the side surface P3. The third tabs 2H, 2I, 2J, and 2K are provided to align the position of the support member 2 to conform to the side surface P3 of the base 1B when assembling the surface mount component 10.

[0034] The support member 2 is positioned to cover or overlap the first surface P1, such that the lens portion 1A of the silicone molded body 1 is inserted through the circular opening H surrounded by the frame portion 2A and exposed.

[0035] In the manufacturing of surface mount components, the silicone molded body and the support member are manufactured in separate processes. The method for manufacturing the silicone molded body is not particularly limited, but specific examples include casting, compression molding, and injection molding. In order to obtain a molded body with suppressed air inclusion, it is particularly preferable to employ casting, in which uncured liquid silicone elastomer is poured into a mold having a cavity in the shape of the silicone molded body using a dispenser, and the silicone elastomer is cured.

[0036] Furthermore, the support members are made of solderable metal material that has been processed by cutting, bending, or pressing. The metal material used to form the support members is not particularly limited, but specific examples include brass, phosphor bronze, aluminum, aluminum alloys, beryllium, chromium, copper, copper alloys, or plated metal materials such as tin-plated metal materials, which can be used without particular limitation.

[0037] In such surface mount components 10, as will be described later, four second tabs 2D, 2E, 2F, and 2G are soldered to pads electrically independent of the wiring pattern of the electrical circuit formed on the surface of the circuit board by a reflow process. The number of second tabs in the support member is not particularly limited as long as there are multiple tabs, but it is preferable to have three to six, and more preferably four, second tabs arranged at equal intervals, for example, diagonally across a rectangle, due to the alignment of the position due to the molten solder in the reflow process and the stability of the solder joint.

[0038] Referring to Figures 1 to 5, the silicone molded body 1 is a silicone elastomer molded body or a silicone resin molded body, comprising a flange-shaped or platform-shaped base portion 1B and a lens portion 1A formed on the first surface P1 of the base portion 1B. The lens portion 1A is a transparent silicone elastomer or silicone resin molded body having a shape optically designed to adjust the light emission from the LED element to the desired light distribution. The silicone molded body 1 has a recess formed on the second surface P2 of the base portion 1B for accommodating electronic components such as LED elements mounted on a circuit board. The recess is provided as needed, but is useful for accommodating and aligning electronic components such as LED elements.

[0039] In the surface mount component 10 of this embodiment, the lens portion 1A has the shape of a convex lens with a thicker center and a thinner periphery. The shape of the lens portion is not limited to such a convex lens, and a shape that changes the optical path when incident light is transmitted and emitted, such as focusing, diffusing, refraction, or reflection of light, can be selected according to the purpose. Specific examples of such shapes include, for example, a concave lens with a thin center and a thicker periphery, a Fresnel lens, a diffractive lens, a cylindrical lens, a double convex lens with convex on both sides, and an asymmetrical lens such as a batwing lens, which can be appropriately selected according to the purpose.

[0040] Furthermore, the shape of the recess formed on the second surface P2 of the base 1B of the silicone molded body 1 for accommodating electronic components is not particularly limited, but it is preferable that the shape conforms to the outer shape of the electronic component in order to facilitate alignment with the electronic component. For example, if the electronic component has a rectangular outer shape, it is preferable that the inner shape of the recess also conforms to the rectangular outer shape of the electronic component. The volume of the recess is preferably about 1.1 to 2 times, and more preferably about 1.15 to 1.5 times, the volume of the electronic component to be accommodated, in order to facilitate alignment. If the volume of the recess is too small relative to the volume of the electronic component to be accommodated, the clearance becomes too small when the electronic component is accommodated, and the alignment of the position by the molten solder in the reflow process tends to decrease.

[0041] As the material for the silicone molded body 1, a molded body of silicone elastomer (including silicone rubber and silicone gel) or a molded body of silicone resin is used because it has light transmittance, making it easy to impart optical functions, and also has excellent heat resistance, heat deformation resistance, and heat discoloration resistance under high-temperature reflow conditions such as lead-free soldering. Silicone elastomer has elastomer elasticity, and silicone resin is a hard resin.

[0042] Among these, a silicone elastomer molded article is preferred, particularly a silicone elastomer molded article conforming to JIS K 6253, with a durometer type A hardness of 40 to 95, and more preferably 50 to 90. With such a silicone elastomer molded article, when it undergoes thermal expansion, the stress due to the volume change is relieved by the elasticity of the elastomer. As a result, the occurrence of cracks, thermal deformation, and displacement due to the thermal expansion of the silicone molded article can be suppressed. In addition, deformation and loosening of the first tab that grips the base due to stress caused by the expansion of the base is suppressed. Furthermore, because the surface tackiness is appropriate, it becomes easier to mount it on circuit boards and the like using a pick-and-place machine.

[0043] The support member 2 and the silicone molded body 1 are molded separately. Then, in the assembly process, after arranging the support member 2 so as to cover the lens portion 1A from the upper surface of the silicone molded body 1, the first tabs 2B and 2C are bent so as to be clamped at predetermined positions on the second surface P2 of the base portion 1B of the silicone molded body 1, and the silicone molded body 1 is integrated with the support member 2, whereby the surface mount component 10 is manufactured.

[0044] Referring to FIGS. 1 to 5, the support member 2 has a frame portion 2A having an opening H, the lens portion 1A is inserted through the opening and exposed, and the frame portion 2A is supported on the first surface P1 where the lens portion 1A of the base portion 1B of the silicone molded body 1 is formed. Further, the support member 2 extends from the outside of the frame portion 2A and is bent while being wound so as to grip the second surface P2 which is the opposite surface of the base portion 1B, and is engaged and fixed, and is bent along the outer shape of the base portion 1B. It has two first tabs 2B and 2C, and four second tabs 2D, 2E, 2F, and 2G which are portions to be soldered and extend outward from the frame portion 2A so as not to overlap the lens portion 1A. Further, the support member 2 extends from the outside of the frame portion 2A and is bent along the side surface P3 of the base portion 1B, and has four third tabs 2H, 2I, 2J, and 2K for aligning with the side surface P3 of the base portion 1B of the silicone molded body 1 during assembly.

[0045] FIG. 6 is a schematic cross-sectional view for explaining a state in which, in the surface mount component 10, the first tabs 2B and 2C are bent while being wound so as to grip the second surface P2 which is the opposite surface to the first surface P1 of the flange-shaped or pedestal-shaped base portion 1B, and the support member 2 is fixed to the base portion 1B. Further, FIG. 7 is a schematic cross-sectional view for explaining a state in which, in the surface mount component 10, the third tabs 2H and 2J are bent along the side surface P3 of the base portion 1B, and their tips are arranged so as to face the side surface P3, thereby aligning with the side surface P3 of the base portion 1B.

[0046] Referring to FIG. 6, in the base 1B, the first tabs 2B and 2C are bent while being wound so as to grip the second surface P2, which is the surface opposite to the first surface P1 on which the support member 2 is disposed, thereby fixing the support member 2 to the base 1B. At this time, as shown in FIG. 6, it is preferable to thin the thickness of the base 1B at the portion covered by the first tab of the base 1B to form a clearance in the portion covered by the first tab of the base 1B. By forming such a clearance, even if the portion covered by the first tab of the base expands due to thermal expansion, in order to absorb the volume change of the base due to thermal expansion with the clearance, the first tab that grips the base can be prevented from being deformed by the stress caused by the expansion of the base and the engagement from loosening.

[0047] When a clearance is formed in the portion covered by the above-described first tabs 2B and 2C, the volume filling rate of the base 1B in the portion covered by the first tabs 2B and 2C is 40 to 80%, and more preferably 50 to 70%. This is preferable in that it can sufficiently suppress the first tabs 2B and 2C from being deformed by the stress caused by the expansion of the base 1B due to thermal expansion and the engagement from loosening. Here, the volume filling rate of the base in the portion covered by the first tab is defined as the volume ratio of the filling rate of the resin of the base in the space formed in the region where the upper and lower surfaces overlap through the bent portion of the first tab that grips the base when viewed in plan. Referring to FIG. 6, it is defined as the volume ratio of the filling rate of the resin of the base 1B in the space S formed in the region (region D in the figure) where the upper and lower surfaces overlap through the bent portion of the first tab 2B that grips the base 1B. In FIG. 6, in the resin portion of the base 1B covered by the first tabs 2B and 2C, it is thinned by a stepped structure to form a clearance in the portion of the base 1B covered by the first tabs 2B and 2C. Instead of forming the clearance in this way, a through hole may be provided in the portion of the base covered by the first tab of the base, or a structure may be provided in which a large number of columns are erected like a pin cushion to provide a void, thereby adjusting the volume filling rate of the portion of the base covered by the first tab. The volume filling rate is measured after the surface-mounted component 10 before mounting is left for 24 hours in an environment of 23°C and 50% RH.

[0048] Furthermore, the second tabs 2D, 2E, 2F, and 2G extend from the frame portion 2A to the outside of the silicone molded body 1 so as not to overlap with the silicone molded body 1. As will be described later, the second tabs 2D, 2E, 2F, and 2G are tabs that are typically electrically independent of the wiring pattern on the surface of the circuit board and are soldered to pads. Also, referring to Figure 7, the third tabs 2H and 2J are pre-bent so as to be aligned with the side surface P3 of the base portion 1B, along the first surface P1 of the base portion 1B and the side surface P3, and have the function of horizontal alignment during assembly.

[0049] The surface mount component 10 described above has a lens as a functional part for adjusting the light emitted by the LED element mounted on the circuit board. The functional part of the silicone molded body of the surface mount component according to the present invention is not limited to a lens. Specific examples of functional parts other than lenses include, for example, optical functions such as wavelength conversion, wavelength filtering, and light guides; protective functions that cover and protect surface-mounted electronic components; and physical or chemical functions such as connecting other members using a snap-fit ​​structure. These can be selected according to the purpose.

[0050] The surface mount component 10 obtained in this manner is then surface-mounted onto a circuit board using surface mount technology (SMT). Specifically, in SMT, solder paste is applied to predetermined pads on the circuit board, electronic components are placed on the predetermined pads using a pick-and-place machine, and the circuit board is heated and passed through a solder reflow furnace with a temperature profile that includes a zone for preheating the solder contained in the solder paste and a zone with a temperature above the melting temperature after preheating, thereby melting the solder. At this time, the electronic components are aligned so that they are joined in the correct position by surface tension. Then, by cooling the molten solder, electrical and physical connections are formed on the predetermined pads of the circuit board through the terminals of the electronic components. In the surface mount component 10 of this embodiment, only physical connections are formed in order to perform only optical functions.

[0051] In this embodiment, the surface mount component 10 has second tabs 2D, 2E, 2F, and 2G that are bent for soldering, which extend outward from the outer shape of the silicone molded body 1 so as not to overlap with it, thus preventing the temperature of the silicone molded body 1 from rising too high. Therefore, even in a reflow process using lead-free solder with a high melting point, it is possible to suppress misalignment, cracking, and thermal deformation caused by excessive thermal expansion of the silicone molded body 1.

[0052] Referring to Figure 8, in this embodiment, the surface mount component 10 is soldered to the circuit board 20, on which the LED element 30 is mounted by soldering 11 to pads 21a and 21b using a reflow process, using soldering 11 to pads 22a, 22b, 22c, and 22d. At this time, the second tabs 2D, 2F, 2E, and 2G of the surface mount component 10 are soldered to the pads 22a, 22b, 22c, and 22d, which are patterns formed electrically independently of the pads 21a and 21b of the wiring pattern on the surface of the circuit board 20.

[0053] The type of LED element is not particularly limited, and surface-mount type LEDs, chip type LEDs, etc., can be used without particular limitation. Furthermore, the emission wavelength of the LED element is not particularly limited, and can be ultraviolet light LED elements, blue LED elements, green LED elements, red LED elements, etc., but deep ultraviolet LED elements that emit UV-C ultraviolet light in the wavelength range of 100 to 280 nm are particularly preferred from the standpoint of the usefulness of surface-mount components. In deep ultraviolet LED elements that emit UV-C ultraviolet light, because UV-C ultraviolet light has high energy, if the optical element is bonded with an adhesive, the adhesive may be damaged and degrade, which can lead to a decrease in light extraction efficiency. By using the surface-mount components described above, the optical element can be attached to the LED element without using an adhesive, thus eliminating the problem of reduced light extraction efficiency due to adhesive degradation.

[0054] The surface mount component 10 and the LED element 30 may be soldered together simultaneously in a single reflow process, or they may be soldered together in separate processes, such as mounting only the surface mount component 10 onto a circuit board 20 with the LED element 30 already mounted and then reflowing and joining them. Furthermore, the surface mount component 10 and the LED element 30 may or may not be in contact.

[0055] The wiring pattern on the circuit board 20 determines the position for mounting electronic components, and the LED element 30 and surface mount components 10 are soldered to their predetermined positions. At this time, the pads 21a and 21b on which the LED element 30 is mounted are on an electrical circuit supplied with current from a power supply (not shown), while the pads 22a, 22b, 22c, and 22d on which the surface mount components 10 are mounted are not on an electrical circuit. In other words, the pads 22a, 22b, 22c, and 22d are electrically independent from the electrical circuit including the pads 21a and 21b. In this way, the surface mount structure 100 shown in Figure 8 is formed.

[0056] Figure 9 also shows a surface mount structure 110 in which a surface mount component 40 has the same configuration as the surface mount component 10, except that a silicone molded body 41 having a wavelength conversion member (functional part) 41A, which is made by compounding a phosphor 42 into a silicone elastomer molded body or a silicone resin molded body, is used as the functional part instead of the lens part 1A.

[0057] The silicone molded body 41 comprises a silicone molded body 41 having a wavelength conversion member 41A and a base portion 41B connected thereto, and a support member 2 which is integrated by assembly.

[0058] The wavelength conversion member 41A is a wavelength conversion member having a wavelength conversion function that contains a phosphor 42 excited by the light emitted by the LED element 30. The wavelength conversion member 41A contains a phosphor for converting the emission color by converting the wavelength of the light emitted from the LED element 30. In addition, it may contain a light diffusing agent or the like for diffusing the light as needed. A specific example of such a phosphor is, for example, Y3Al5O 12YAG phosphors, in which some of the Y atom positions are substituted with Gd and typically activated with cerium (Ce), etc.; europium-activated strontium aluminate (SAE) phosphors; aluminate phosphors; silicate phosphors; β-SiAlON (Si-Al-ON) phosphors such as β-SiAlON:Eu and β-SiAlON:Ca; LuAG (Lu₃Al₅O₁₂) phosphors; CaS:Eu, CaAlSiN ３ Examples of light diffusing agents include CASN-based phosphors such as Eu. These may be used individually or in combination of two or more. Specific examples of light diffusing agents include, for example, glass powder and inorganic fillers such as calcium carbonate, titanium dioxide, zinc oxide, silica, barium sulfate, and alumina.

[0059] With this method of mounting surface-mount components 40 onto the circuit board 20, the color of the light emitted by the LED element 30 can be adjusted simply by soldering the surface-mount components 40 to the circuit board 20 through a reflow process.

[0060] Figure 10 is a partially schematic cross-sectional view illustrating surface mount structures 120 and 130, which include a surface mount component 50 having a male snap-fit ​​part (functional part) 51A, a surface mount component 60 having a female snap-fit ​​part (functional part) 61A, a circuit board 70 on which the two surface mount components 50 are mounted, and a circuit board 80 on which the two surface mount components 60 are mounted, with the circuit boards 70 and 80 being physically connected by a snap-fit ​​structure. Figure 10(a) shows the partial cross-sectional structure before connection, and Figure 10(b) shows the partial cross-sectional structure after connection.

[0061] A snap-fit ​​structure is a design that allows two parts to be connected by pushing them together without the use of special tools or adhesives. Figure 10 illustrates how circuit board 70 and circuit board 80 are connected.

[0062] Referring to Figure 10, the surface mount component 50 comprises a silicone molded body 51, which is a silicone elastomer molded body or silicone resin molded body having a male shape portion 51A with a snap-fit ​​structure and a base portion 51B connected to the male shape portion 51A, and a support member 52 integrated with the silicone molded body 51 by assembly. Similarly, the surface mount component 60 comprises a silicone molded body 61, which is a silicone elastomer molded body or silicone resin molded body having a female shape portion 61A with a snap-fit ​​structure and a base portion 61B connected to the female shape portion 61A, and a support member 62 integrated with the silicone molded body 61 by assembly.

[0063] Surface mount component 50 has the same shape as surface mount component 10, except that instead of the silicone molded body 1 which has a lens portion 1A as a functional part, a silicone molded body 51 which is a silicone elastomer molded body or silicone resin molded body having a snap-fit ​​male shape portion 51A and a base portion 51B connected to the male shape portion 51A is used. Similarly, surface mount component 60 has the same shape as surface mount component 10, except that instead of the silicone molded body 1, a silicone molded body 61 which is a silicone elastomer molded body or silicone resin molded body having a snap-fit ​​male shape portion 61A and a base portion 61B connected to the male shape portion 61A is used.

[0064] The support member 52 has a rectangular frame portion having a circular opening that exposes the male portion 51A, two first tabs extending outward from the frame portion and bent along the outer shape of the base portion 51B to grasp and fix the base portion 51B, and second tabs 52D, 52E, 52F, 52G that extend outward from the frame portion so as not to overlap the male portion 51A and are soldered portions. The support member 62 has a rectangular frame portion having a circular opening that exposes the female portion 61A, two first tabs extending outward from the frame portion and bent along the outer shape of the base portion 61B to grasp and fix the base portion 61B, and second tabs 62D, 62E, 62F, 62G that extend outward from the frame portion so as not to overlap the female portion 61A and are soldered portions.

[0065] The support member 52 is positioned to cover the upper surface of the silicone molded body 51 so that the male-shaped portion 51A is inserted through a circular opening and exposed. The support member 62 is positioned to cover the upper surface of the silicone molded body 61 so that the female-shaped portion 61A is inserted through a circular opening and exposed.

[0066] Surface mount components 50 are soldered to pads 72a, 72b, 72c, and 72d, which are patterns formed on the circuit board 70, by second tabs 52D, 52E, 52F, and 52G. Similarly, surface mount components 60 are soldered to pads 82a, 82b, 82c, and 82d, which are patterns formed on the circuit board 80, by second tabs 62D, 62E, 62F, and 62G. Pads 72a, 72b, 72c, and 72d are electrically independent from the electrical circuits formed on the circuit board 70.

[0067] As shown in Figures 10(a) and 10(b), a circuit board 70 with two surface-mount components 50 mounted on it and a circuit board 80 with two surface-mount components 60 mounted on it are arranged facing each other, and the male part 51A having a snap-fit ​​male shape and the female part 61A having a snap-fit ​​female shape are pressed together and fitted into each other, thereby physically connecting the circuit board 80 to the circuit board 70 by stacking them on top of each other.

[0068] The surface mount components and surface mount structures in this embodiment have been described in detail above with reference to specific examples. The scope of the present invention is not limited to these specifically described embodiments of surface mount components and surface mount structures.

[0069] 1, 41, 51, 61 Silicone molded body 1A Lens part (functional part) 1B Base part 2, 52, 62 Support member 2A Frame part 2B, 2C First tab 2D, 2E, 2F, 2G Second tab 2H, 2I, 2J, 2K Third tab 10, 40, 50, 60 Surface mount component 20, 60, 70, 80 Circuit board 21a, 21b, 22a, 22b, 22c, 22d Pad 72a, 72b, 72c, 72d Pad 82a, 82b, 82c, 82d Pad 30 LED element 41A Wavelength conversion member (functional part) 51A, 61A Snap-fit ​​structure (functional part) 42 Phosphor 100, 110, 120, 130 Surface mount structure P1 First surface P2, Second surface P3, Side H, Opening

Claims

1. A surface mount component that is soldered to a circuit board by a reflow process, comprising: a silicone molded body having a base and a functional part formed on a first surface of the base; and a metal support member integrated with the silicone molded body by assembly, wherein the support member has a frame and a plurality of first tabs and second tabs extending from the outside of the frame, the frame is positioned on the first surface with the functional part exposed through an opening it surrounds, the first tabs are tabs that fix the support member to the base, bent while wrapping around a second surface which is the opposite surface of the first surface, and the second tabs are bent so as to extend outwards from the silicone molded body without overlapping it.

2. The surface mount component according to claim 1, wherein the volume filling rate of the portion of the base covered by the first tab, in the portion where the base and the first tab overlap when viewed from above, is 40 to 80%.

3. The surface mount component according to claim 1, wherein the support member has a plurality of third tabs extending from the outside of the frame, and the third tabs are bent to follow the side surface of the base so that their tips face the side surface.

4. The surface mount component according to claim 1, wherein the silicone molded body is a silicone elastomer molded body.

5. The surface mount component according to claim 4, wherein the silicone elastomer molded body is a molded body of silicone elastomer having a durometer type A hardness of 40 to 95 in accordance with JIS K 6253.

6. The surface mount component according to claim 1, wherein the functional part is an optical element that covers an LED element mounted on the circuit board and adjusts the light emitted by the LED element.

7. The surface mount component according to claim 6, wherein the optical element is a lens member for adjusting the light distribution of the light emitted by the LED element.

8. The surface mount component according to claim 6, wherein the optical element is a wavelength conversion member containing a phosphor that is excited by the light emitted by the LED element.

9. The surface mount component according to claim 6, wherein the silicone molded body has a recess on the second surface for housing the LED element.

10. The surface mount component according to claim 6, wherein the LED element is a deep ultraviolet LED element that emits UV-C ultraviolet light in the wavelength range of 100 to 280 nm.

11. The surface mount component according to claim 1, wherein the silicone molded body has the shape of a male or female snap-fit ​​structure.

12. A surface mount structure in which a surface mount component according to any one of claims 1 to 11 is surface mounted on the circuit board.

13. A method for manufacturing a surface mount component to be soldered to a circuit board by a reflow process, comprising: a step of preparing a silicone molded body having a base and a functional part formed on a first surface of the base; a step of preparing a metal support member having a frame and a plurality of first tabs, second tabs and third tabs extending from the outside of the frame, wherein when assembled, the first tab is a tab for fixing the support member to the base, which is bent to grasp the second surface which is the opposite surface of the first surface, the second tab is a tab which is bent to extend to the outside of the silicone molded body so as not to overlap the silicone molded body, and the third tab is a tab which is bent along the side surface of the base and whose tip is positioned facing the side surface; a step of exposing the functional part from an opening surrounded by the frame and positioning the frame on the first surface such that the third tab is along the side surface of the base; A method for manufacturing a surface mount component, comprising the step of fixing the support member to the base by bending the first tab while wrapping it around the second surface.

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