Light source apparatus

Abstract

To provide a light source apparatus that can suppress the generation of migration without requiring a complex structure.SOLUTION: A light source apparatus includes: an LED substrate that has a first conductive layer and a second conductive layer that are made of a metal material and provided adjacent to each other; an LED element that is mounted on the second conductive layer and has a first electrode provided on a light emission surface and a second electrode provided on a surface opposite to the light emission surface; wire wiring that connects the first electrode of the LED element and the first conductive layer; a metal junction layer that contains at least silver and is formed between the LED element and the second conductive layer on the second conductive layer; and a resin layer that is formed along the periphery of the LED element and covers a surface of the metal junction layer. In an extending direction of the wire wiring, the resin layer is formed in a narrow alley along a side face of the LED element between the LED element and an edge of the second conductive layer or a partition part provided on the second conductive layer.SELECTED DRAWING: Figure 4A

Description

Technical Field

[0001] The present invention relates to a light source device, and particularly to a light source device including an LED element.

Background Art

[0002] A light source device on which an LED element is mounted is generally realized by mounting the LED element on a mounting substrate according to the application. As a material used when mounting the LED element on the substrate, silver (Ag) paste is often adopted in many cases in consideration of heat dissipation and cost.

[0003] In a light source device in which an LED element is mounted using silver paste, when a voltage is applied to the LED element in a high-humidity environment, a phenomenon called migration occurs in the vicinity of the electrode (anode) of the LED element (sometimes also referred to as "ion migration"). Here, migration specifically refers to a phenomenon in which silver contained in the silver paste and moisture existing around the LED element come into contact with each other, and when a voltage is applied thereto, silver and silver oxide are deposited.

[0004] While a voltage is being applied to the LED element, as long as silver and moisture are present, silver and silver oxide continue to be deposited due to this migration. And the substance deposited near one electrode of the LED element gradually spreads in a stain-like manner toward the other electrode side, and ultimately, there is a risk that the substance deposited by migration will short-circuit between the electrodes. Short-circuiting between the electrodes leads to non-lighting or destruction of the LED element, thus greatly affecting the reliability. For this reason, methods for suppressing the occurrence of migration as described above have been studied.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] For example, in Patent Document 1 mentioned above, a method for suppressing the occurrence of migration by suppressing the irradiation of light (also referred to as "return light") that is returned to the LED element side among the light emitted from the LED element onto the silver paste is described. The method described in Patent Document 1 aims to suppress the ionization of silver caused by the irradiation of light emitted from the LED element onto the silver paste, thereby suppressing the occurrence of migration.

[0007] However, the structure described in Patent Document 1 mentioned above is such that on a substrate on which an LED element is mounted, a recess for accommodating the LED element and filling a light-shielding material for shielding a part of the light traveling toward the silver paste is filled in the recess. And the recess described in Patent Document 1 has an opening that is slightly larger than the light-emitting surface of the LED element.

[0008] Forming a recess on the substrate on which the LED element is mounted and filling an appropriate amount of light-shielding material in the recess may complicate the structure of the light source device, increase the manufacturing process and manufacturing cost, and further require more precise control in the mounting process of the LED element. For this reason, the structure described in Patent Document 1 has a problem that it is difficult to adopt in reality for the above reasons.

[0009] In view of the above problems, the light source device of the present invention aims to provide a light source device in which the occurrence of migration is suppressed.

Means for Solving the Problems

[0010] The light source device of the present invention has an LED substrate having a first conductive layer and a second conductive layer made of adjacent metal materials on a main surface, an LED element mounted on the second conductive layer, having a first electrode provided on a light-emitting surface and a second electrode provided on a surface opposite to the light-emitting surface. A wire wiring that connects the first electrode of the LED element and the first conductive layer, A metal bonding layer containing at least silver, which is formed on the second conductive layer and between the LED element and the second conductive layer, And a resin layer formed along the periphery of the LED element and covering the surface of the metal bonding layer. In the direction in which the wire wiring extends, the resin layer is formed in a narrow path along the side surface of the LED element between the LED element and the end of the second conductive layer or a partition provided on the second conductive layer.

[0011] In this specification, the "direction in which the wire wiring extends" is used with the intention of referring to the direction along the line connecting each connection point to which each end of the wire wiring is connected. That is, in reality, even when the wire wiring extends straight, or when it is bent or meandering, the "direction in which the wire wiring extends" is specified based on the positions of each connection point to which the wire wiring is connected.

[0012] Also, in this specification, the "narrow path" refers to a gap portion that is formed on the region of the second conductive layer and remains between the LED element and the end of the second conductive layer or a partition provided on the second conductive layer, and is a region configured with a width of 3 mm or less for the separation distance between the LED element and the end of the second conductive layer or a partition provided on the second conductive layer. Note that the smaller the width of the narrow path, the easier it is for the resin material to spread along the narrow path. Therefore, the width of the narrow path is preferably 2 mm or less, and more preferably 1 mm or less. By forming such a narrow path, even if the amount of the resin material is small, the resin layer is likely to be formed in the desired region, and the surface of the metal bonding layer is likely to be covered with the resin layer. Note that the narrow path is not limited to a path with a predetermined width, and it is also assumed that it is a part of the mounting portion that appears around the LED element when viewed from a direction orthogonal to the light emitting surface of the LED element due to the LED element being arranged on the mounting portion on the second conductive layer.

[0013] Also, as will be described in detail in the section "Detailed Description of the Invention", the partition here may be any part having a structure that functions to prevent the resin material before solidification from spreading by wetting. Specifically, a material having a lower surface free energy than the metal material is selected. The partition is, for example, a wall formed of a resin material different from the resin material for forming the resin layer, which is formed on the second conductive layer, a resist material, or a collection of slits and holes formed by removing a part of the second conductive layer.

[0014] As described above, among the factors of migration, in addition to the silver being irradiated with light, there may be a case where silver comes into contact with moisture present around the LED element. However, compared to blocking light, it is easier to suppress the contact with moisture. This is generally because the absorption rate of light in the material used for light shielding varies for each wavelength of light.

[0015] In the light source device having the above configuration, the metal bonding layer formed around the LED element, that is, the portion where silver and moisture may come into contact, is covered with the resin layer. For this reason, the contact between the metal bonding layer and the moisture present around the LED element is suppressed, and the occurrence of migration is suppressed.

[0016] Here, mounting the LED element on the flat second conductive layer provided on the main surface of the LED substrate, filling the gap between the LED element and the second conductive layer, and covering the surface of the metal bonding layer spreading around the LED element with the resin layer will be described.

[0017] The resin layer is formed by supplying the resin material before solidification to the surface of the metal bonding layer and solidifying it by heat treatment or irradiation with ultraviolet light. At this time, the liquid resin material may be directly applied to the surface of the metal bonding layer. However, if the LED element is thin and small, it is difficult to directly apply it to the surface of the metal bonding layer. Further, if the arrangement density of the LED elements is high, it becomes more difficult to directly apply it to the surface of the metal bonding layer.

[0018] Therefore, the inventor noticed that the surface free energy is relatively high on the conductive layer made of a metal material or on the metal bonding layer, and the resin material before solidification is likely to spread by wetting. The inventor considered using this property.

[0019] In the light source device having the above configuration, even if the resin material before solidification is not directly applied to the metal bonding layer, if a sufficient amount of the resin material before solidification is supplied to an arbitrary position of the second conductive layer, the resin will naturally spread by wetting. By restricting the area where the resin spreads (the area where the resin material and the second conductive layer come into contact), the spread of the resin to undesired areas can be restricted. For example, around the LED element, the resin material can be supplied to the entire surface of the metal bonding layer.

[0020] That is, with the above configuration, even on a flat second conductive layer without forming any complex structure on the LED substrate, a resin layer can be formed over the entire surface of the metal bonding layer existing around the LED element. By forming narrow paths on the second conductive layer where the resin material spreads by wetting, the resin material can easily spread along the narrow paths, and a resin layer can be formed around the LED element. Also, by forming the resin in the narrow paths, even if the amount of the resin material before solidification supplied to the second conductive layer (supply amount) is small, it becomes easier to form a resin layer along the narrow paths.

[0021] There is no need to increase the amount of the resin material supplied to the second conductive layer, and it is possible to prevent the resin material from spreading to undesired areas. And by spreading the resin material along the narrow paths, it is easy to control so that the resin material does not climb onto the light emitting surface of the LED element. That is, by adopting a structure in which the light emitting surface of the LED element is not covered with the resin material, it is possible to prevent the light (for example, ultraviolet light) radiated from the light emitting surface from being absorbed by the resin material.

[0022] In addition to the above considerations, when the inventor examined the path along which the resin material spreads by wetting, the inventor also considered the presence of wire wirings and examined the structure of the second conductive layer around the LED element.

[0023] Since wire wiring generally adopts metal material wiring from the viewpoints of conductivity, flexibility, ease of processing, etc., if it comes into contact with the resin material before solidification, there is a risk of sucking up the resin material. If the wire wiring sucks up the resin material, the resin material may inadvertently spread and wet the light-emitting surface of the LED element, potentially reducing the brightness of the LED element. Therefore, depending on the order of the manufacturing process and considering the ability to handle all manufacturing processes, it is necessary to avoid contact between the wire wiring and the resin material. However, when attempting to apply a resin material that covers the surface of the metal bonding layer around the LED element in the direction in which the wire wiring extends, it becomes difficult to avoid contact between the wire wiring and the resin material.

[0024] On the other hand, the structure of the above-described light source device forms a narrow path along the area where the resin material is desired to spread, and forms a resin layer in the narrow path. Therefore, the resin material spreads along the narrow path, and even a small amount can easily form a resin layer covering the surface of the metal bonding layer. Also, since the resin layer is formed along the narrow path, the resin layer is less likely to bulge, and contact between the wire wiring and the resin material is more easily avoided.

[0025] Note that the resin layer can be easily formed by forming a narrow path along the side surface of the LED element, even if it is not in the direction in which the wire wiring extends. For example, the narrow path may be formed along a part of the side surface of the LED element, or may be formed along the entire circumference of the LED element.

[0026] The light source device having the above configuration has a structure in which it is difficult for the wire wiring to come into contact with the resin material that spreads and wets the surfaces of the second conductive layer and the metal bonding layer. Therefore, it is easier to avoid the resin material for forming the resin layer from spreading along the wire wiring and inadvertently wetting the light-emitting surface.

[0027] Note that one end of the wire wiring is bonded on the light emitting surface, and when going toward the first conductive layer side, after passing through a position higher than the LED element once with reference to the main surface of the LED substrate, the other end is bonded to a predetermined position of the first conductive layer. Therefore, in the vicinity of the LED element, the wiring is necessarily arranged so as to avoid the resin material. However, due to the operation of the bonding process, in the vicinity of the position corresponding to exactly the middle part of each bonding position, the height from the main surface of the LED substrate is likely to change, and the wire wiring and the second conductive layer are likely to approach each other. Also, it is conceivable that the wire wiring may be brought closer to the second conductive layer by an undesired external stress. At this time, if the wire wiring approaches the second conductive layer too much, there is a possibility of short circuit, and it is desirable that a resin layer is interposed between the second conductive layer and the wire wiring.

[0028] Also from this point, preferably, in the direction in which the wire wiring extends, a resin layer is formed in a narrow path along the side surface of the LED element between the LED element and the end of the second conductive layer or the partition provided on the second conductive layer.

[0029] In the above light source device, The surface of the resin layer gradually becomes smaller as the height with reference to the main surface of the LED substrate increases away from the LED element, and may be linear or concave in a cross section when cut by a plane parallel to the side surface of the LED element and passing through the LED element.

[0030] With the above configuration, it is possible to more preferably avoid contact between the resin material before curing for forming the resin layer and the wire wiring. Note that depending on the viscosity of the resin material, etc., if a resin material with a relatively low viscosity is adopted and the resin material is supplied as it is along the narrow path without using a mold or the like, the resin layer is likely to be formed so as to naturally exhibit the above shape.

[0031] In the above light source device, When viewed in the normal direction of the main surface of the LED substrate with the LED element mounted thereon, a mounting portion formed within a region surrounded by the mounted LED element, an end portion of the second conductive layer, or a partition portion provided on the second conductive layer, It may also include an extension portion that extends in a direction away from the LED element toward the outside of the mounting portion when viewed from the LED element.

[0032] Furthermore, in the above light source device, The partition portion is preferably made of a material having a smaller surface free energy than the metal material forming the second conductive layer.

[0033] Also, in the above light source device, The partition portion is provided to partition a part of the region on the first conductive layer, and the wire wiring may be connected to the region partitioned by the partition portion.

[0034] With the above configuration, it is possible to prevent the resin material before solidification for forming the resin layer from spreading unnecessarily on the second conductive layer.

[0035] Also, depending on the device for supplying the resin material before solidification for forming the resin layer, the discharge port for supplying the resin material may be large, and it may be difficult to accurately supply the resin material to a narrow region. Therefore, if an extension portion continuous with the mounting region is formed as in the above configuration, the supply of the resin material becomes relatively easy. Furthermore, by forming the extension portion with a prescribed size and shape, it can also be used as an alignment for detecting the position where the resin material is supplied.

[0036] Also, it is more preferable that the extension portion is formed so as to be continuous with only a part of the mounting region. This is because if the extension portion is formed around the entire circumference of the mounting region, the supplied resin material will spread outside the mounting region, making it difficult to control the spread of the resin. Specifically, it is more preferable that the distance where the extension portion is continuous with the mounting region is suppressed to 50% or less of the circumference of the mounting region.

[0037] Also, in the above light source device, It is preferable that the area of the extension part is smaller than the mounting area of the LED element.

[0038] Also, in the above light source device, A plurality of the extension parts may be provided corresponding to one mounting part.

[0039] The above light source device At least a portion of the second conductive layer located between the LED element and the first conductive layer may be covered with the resin layer.

[0040] Wire wiring may be greatly bent between the LED element and the first conductive layer due to, for example, deformation caused by contact during assembly work, operation during bonding, or deformation caused by the application of gravity and heat over a long period of time. For this reason, if the second conductive layer located between the LED element and the first conductive layer is exposed, the bent wire wiring may come into contact with the exposed portion, resulting in a short circuit between the first conductive layer and the second conductive layer.

[0041] Therefore, with the above configuration, even when the wire wiring is bent, a short circuit between the first conductive layer and the second conductive layer due to the wire wiring is avoided.

Advantages of the Invention

[0042] According to the present invention, a light source device in which the occurrence of migration is suppressed is realized without requiring a complicated structure.

Brief Description of the Drawings

[0043]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 5E

Best Mode for Carrying Out the Invention

[0044] Hereinafter, the light source device of the present invention will be described with reference to the drawings. Note that each of the following drawings is schematically illustrated, and the dimensional ratios and numbers on the drawings do not necessarily match the actual dimensional ratios and numbers.

[0045] FIG. 1 is a schematic drawing of an entire one embodiment of the light source device 1 when viewed from the +Z side. FIG. 2 is a drawing schematically showing adjacent conductive layers (11a, 11b). FIG. 3A is an enlarged view of region R1 in FIG. 2, and FIG. 3B is a drawing of the state where the resin layer 6 formed on the first conductive layer in FIG. 3A has been removed. And FIG. 4A is a cross-sectional view taken along line A-A of FIG. 3A.

[0046] As shown in FIGS. 1 to 4A, the light source device 1 in this embodiment includes an LED substrate 10, a pair of substrate electrodes (2a, 2b), an LED element 3, a wire wiring 4, a conductive layer 11, a partition portion 40a, a metal bonding layer 5, and a resin layer 6. In this embodiment, as an example of the light source device 1, a configuration in which a plurality of LED elements 3, wire wirings 4, and conductive layers 11 are provided is shown. However, the light source device 1 may be configured to include one of each of these.

[0047] In the following description, as shown in FIG. 1, a plane parallel to the main surface 10a of the LED substrate 10 is defined as the XY plane, and a direction orthogonal to the XY plane, that is, the normal direction of the main surface 10a of the LED substrate 10 is defined as the Z direction. Then, as shown in FIG. 2, the direction in which the wire wiring 4 extends is described as the Y direction.

[0048] When expressing a direction, when distinguishing between positive and negative directions, it is described with positive and negative signs such as “+Z direction” and “-Z direction”. When expressing a direction without distinguishing between positive and negative directions, it is simply described as “Z direction”.

[0049] As shown in FIG. 4A, the LED element 3 is an element having a structure in which a pair of electrodes (31a, 31b) are formed on surfaces facing each other in the Z direction. The electrode to which the wire wiring 4 on the +Z side is connected corresponds to the first electrode 31a, and the electrode formed on the -Z side surface corresponds to the second electrode 31b.

[0050] The +Z side surface on which the first electrode 31a of the LED element 3 is formed is a light emitting surface 30 for extracting light generated inside a region different from the first electrode 31a. Regarding the LED element 3 employed in the present invention, the wavelength band of the light emitted is arbitrary.

[0051] The wire wiring 4 is a metal wire for connecting the first electrode 31a of the LED element 3 and the first conductive layer 11a. As the material of the wire wiring 4, for example, gold (Au) is used.

[0052] As shown in FIG. 1, the LED substrate 10 has a plurality of conductive layers 11 formed thereon, and a plurality of LED elements 3 are mounted on each conductive layer 11. In the light source device 1 of the present embodiment, the conductive layers 11 are connected in series by a plurality of LED elements 3 and wire wirings 4, and all the LED elements 3 are configured to light up by supplying predetermined power between the substrate electrodes (2a, 2b).

[0053] As shown in FIG. 2, for a pair of adjacent conductive layers 11 connected by an LED element 3 and a wire wiring 4, the conductive layer 11 to which the wire wiring 4 is connected corresponds to the first conductive layer 11a, and the conductive layer 11 on which the LED element 3 is mounted corresponds to the second conductive layer 11b.

[0054] Note that which conductive layer 11 corresponds to the first conductive layer 11a and which corresponds to the second conductive layer 11b is not uniquely determined, but is determined according to which LED element 3 is focused on.

[0055] The conductive layer 11 is a layer made of a conductive metal material, and as a specific example, it is formed of a material containing copper (Cu), gold (Au), nickel (Ni), palladium (Pd), or an alloy thereof.

[0056] As shown in FIG. 4A, the adjacent conductive layers 11 forming a pair of the first conductive layer 11a and the second conductive layer 11b are formed so as to be separated by a distance d1. The distance d1 needs to ensure sufficient insulation between the first conductive layer 11a and the second conductive layer 11b and to ensure a sufficient distance so that the first conductive layer 11a and the second conductive layer 11b do not short-circuit due to deposits or the like.

[0057] Also, if the distance d1 is too large, there may be problems such as electrical resistance due to the wire wiring 4 and bending of the wire wiring 4. In view of the above points, the distance d1 is preferably 0.10 mm or more and 5.00 mm or less, and more preferably 0.10 mm or more and 3.00 mm or less.

[0058] On the conductive layer 11, partition portions (40a, 40b) are formed to prevent the resin material for forming the resin layer 6 described later from spreading. The partition portion 40a is, for example, a structure that surrounds the mounting portion 12 (the region surrounded by the broken line in FIG. 3B) where the LED element 3 is mounted, together with the end of the second conductive layer 11b. Here, the mounting portion 12 refers to the region of the second conductive layer 11b within the mounting area defined as a range 20% larger than one side of the LED element 3 when viewed in the Z direction. Further, the partition portion 40b here is a structure that forms an extension portion 13 (the region surrounded by the dashed-dotted line in FIG. 3B) having an area smaller than the mounting area of the LED element 3 for supplying the resin material for forming the resin layer 6.

[0059] The partition portions (40a, 40b) are structures made of a material having a smaller surface free energy than the metal material. Materials having a smaller surface free energy than the metal material are, for example, resist, resin, etc. Note that each region shown in FIG. 3B is a region partitioned by the partition portions (40a, 40b) and the end of the second conductive layer 11b, and is formed so as to partition the region of the mounting portion 12. However, for the sake of illustration, the broken line and the dashed-dotted line are shown at positions slightly shifted inward with respect to the actual region.

[0060] The partition portions (40a, 40b) are provided only to receive the resin material for forming the resin layer 6 and guide it to cover the surface of the metal bonding layer 5. Therefore, considering that the resin material generally has a certain degree of viscosity compared to water, the partition portions (40a, 40b) may be continuously extended so as to partition the mounting portion 12, or may be discretely arranged so as to partition the mounting portion 12.

[0061] Also, in this embodiment, one mounting portion 12 is connected to one extension portion 13, but a plurality of mounting portions 12 may be connected to one extension portion 13.

[0062] As shown in FIG. 4A, the metal bonding layer 5 is a layer that connects the second conductive layer 11b and the second electrode 31b of the LED element 3, and is a layer that exhibits conductivity. As shown in FIGS. 3B and 4A, the metal bonding layer 5 is formed in the gap between the LED element 3 and the second conductive layer 11b and around the LED element 3.

[0063] When the LED element 3 is placed on the second conductive layer 11b coated with silver paste, the silver paste is pushed by the LED element 3 and spreads to fill the gap between the second electrode 31b and the second conductive layer 11b. At the same time, as shown in FIG. 3B, the excess silver paste spreads so as to be extruded around the LED element 3. The silver paste that has spread in this way is fixed by heat treatment, drying treatment, etc., so that the metal bonding layer 5 is formed between the LED element 3 on the second conductive layer 11b and the second conductive layer 11b and around the LED element 3.

[0064] As shown in FIGS. 3A to 4A, the LED element 3 is placed at a position separated from the end of the second conductive layer 11b by a certain distance d2. Such a mounting method can effectively prevent the excess silver paste from protruding from between the LED element 3 and the conductive layer 11 and flowing out between the first conductive layer 11a and the second conductive layer 11b, which may cause a short circuit. In the present embodiment, the LED element 3 is arranged such that the side surface of the +Y side of the LED element 3 and the end of the second conductive layer 11b are separated by a distance d2, and a buffer region 12a extending along each side surface of the LED element 3 is formed around the LED element 3.

[0065] As shown in FIG. 4A, it is assumed that the wire wiring 4 may droop toward the LED substrate 10 particularly from the vicinity where it passes through the side surface of the LED element 3 as it goes toward the first conductive layer 11a. Therefore, from the viewpoint of preventing the wire wiring 4 from contacting the resin material before solidification as much as possible, the distance d2 is configured to be smaller than the distance d1.

[0066] The LED element 3 of the present embodiment is similarly arranged on the -X side of the LED element 3 so as to be separated from the end of the second conductive layer 11b by a distance d2. However, the separation distance between the LED element 3 and the end of the second conductive layer 11b on the -X side may be different from the distance d2.

[0067] As shown in FIGS. 3A and 4A, the resin layer 6 is an insulating layer that covers the surface of the metal bonding layer 5 cured around the LED element 3 and the second conductive layer 11b in the direction in which the wire wiring 4 passes, which is located on the +Y side of the LED element 3, and is a layer that is difficult to pass moisture through. As the material constituting the resin layer 6, for example, a hydrophobic resin such as a silicone resin can be adopted. When the wire wiring 4 passes through a position sufficiently separated from the second conductive layer 11b, the second conductive layer 11b at the portion where the wire wiring 4 passes through the +Z side does not have to be entirely covered with the resin layer 6. Also, regarding the position where the wire wiring 4 of the second conductive layer 11b does not pass through the +Z side, except for the portion where the metal bonding layer 5 is formed, whether or not to form the resin layer 6 is arbitrary. For example, it may cover the periphery of the LED element 3, and the resin layer 6 may be formed on at least a part of the partition portions (40a, 40b).

[0068] As shown in FIG. 4A, the resin layer 6 of the present embodiment is formed to be parallel to the side surface of the LED element 3 and to have a concave shape in a cross section when cut along a plane passing through the LED element 3.

[0069] The resin layer 6 is formed by the resin material dropped onto the extension portion 13 of the second conductive layer 11b in the state shown in FIG. 3B spreading over the second conductive layer 11b formed of a metal material having a relatively large surface free energy. When it spreads around the LED element 3, it spreads over the surface of the metal bonding layer 5 having a relatively large surface free energy like the second conductive layer 11b and reaches the side surface of the LED element 3. At this time, since the resin material actively spreads over the second conductive layer 11b and the metal bonding layer 5 rather than the side surface of the LED element 3, it spreads to cover the periphery of the LED element 3 without covering the light emitting surface 30 of the LED element 3. Further, a narrow path is formed between the LED element 3 and the end of the second conductive layer 11b or the partition portions (40a, 40b) provided on the second conductive layer 11b, so that the resin material spreads along the narrow path and is less likely to spread to an undesired area.

[0070] In this way, the resin material spreads over the second conductive layer 11b and the surface of the metal bonding layer 5 and dries and solidifies, thereby forming a resin layer 6 having a shape as shown in FIGS. 3A and 4A.

[0071] Note that the shape of the resin layer 6 in the A-A cross section is preferably linear or concave from the viewpoint of avoiding contact with the wire wiring 4, but may be convex when a sufficient distance can be secured from the wire wiring 4. The shape of the resin layer 6 can be adjusted, for example, by controlling the viscosity of the resin.

[0072] In the light source device 1 having the above configuration, the metal bonding layer 5 formed around the LED element 3, that is, the portion where silver and moisture may come into contact is covered with the resin layer 6. For this reason, contact between the metal bonding layer 5 and the moisture present around the LED element 3 is suppressed, and the occurrence of migration is suppressed.

[0073] Further, in the light source device 1 having the above-described configuration, without forming any complicated structure on the LED substrate 10, the resin layer 6 is formed over the entire surface of the metal bonding layer 5 that exists around the LED element 3 and is on the flat second conductive layer 11b. Also, by appropriately adjusting the amount of the resin material supplied to the second conductive layer 11b, it is possible to control so that the resin material does not climb onto the light emitting surface 30 of the LED element 3.

[0074] Furthermore, the light source device 1 having the above-described configuration has a structure in which the wire wiring 4 is less likely to come into contact with the resin material that spreads wetly over the surfaces of the second conductive layer 11b and the metal bonding layer 5. Therefore, it is easy to avoid the resin material for forming the resin layer 6 from spreading wetly over the light emitting surface 30 unintentionally along the wire wiring 4.

[0075] FIG. 4B is a schematic cross-sectional view showing the same part as FIG. 4A of an embodiment of the light source device 1 different from the above-described configuration. As shown in FIG. 4B, a partition portion 40c may be formed between the first conductive layer 11a and the second conductive layer 11b. Also, in the present embodiment, as shown in FIG. 4B, the partition portions (40a, 40c) are formed so as to cover a wider range of the first conductive layer 11a and the second conductive layer 11b. Thereby, it becomes difficult for the wire wiring 4 to come into contact with the first conductive layer 11a or the second conductive layer 11b, and it becomes difficult for a short circuit to occur. Also, the narrow path here will be formed in the gap between the LED element 3 and the partition portion 40c provided on the second conductive layer 11b, and a narrow path narrower than the distance d2 will be formed. Regarding the partition portion 40c in the said structure, as a function, it is the same as the partition portions (40a, 40b), but they do not all have to be formed of the same material.

[0076] [Another Embodiment] Hereinafter, another embodiment will be described.

[0077] <1> Figures 5A to 5D are schematic drawings when viewing another embodiment of the light source device 1 from the Z direction, and Figure 5E is a cross-sectional view taken along line B-B of Figure 5D. The light source device 1 described here is described on the premise that, for convenience of explanation, one LED element 3 is mounted on the LED substrate 10. However, as in the above-described embodiment, it is of course assumed that it can be applied when a plurality of LED elements 3 are mounted.

[0078] As shown in FIGS. 5A and 5B, the second conductive layer 11b may be composed of a mounting portion 12 and an extension portion 13 without providing a partition portion. Further, the shape of the extension portion 13 is arbitrary, and it may be a shape that is continuous with the region of the mounting portion 12 of the LED element 3 and has a region that expands outside the region of the mounting portion 12.

[0079] Also, as shown in FIG. 5C, the mounting portion 12 and the extension portion 13 may be formed by a slit 14 provided on the second conductive layer 11b. Further, the slit 14 may be replaced by a set of through-holes or the like.

[0080] Also, FIGS. 5D and 5E show an embodiment in which the second conductive layer 11b is smaller than the mounting region 10b for the LED element 3. The mounting region 10b here is defined in a range 20% larger than one side of the LED element 3. Further, the "narrow path" in the present embodiment is a region having a width of the distance d2 between the LED element 3 and the end of the second conductive layer 11b. According to the present embodiment, by making the second conductive layer 11b narrower than the mounting region 10b, a narrower narrow path can be formed along the side surface of the LED element 3.

[0081] For example, by forming a narrow path in which the distance between the LED element 3 and the end of the second conductive layer 11b is 0.02 mm, the resin can also be wet and spread along the narrow path.

[0082] When forming a narrow path by the partition portion 40d, if the narrow path is too narrow, in the process of spreading the resin material before solidification, the resin material is likely to fill the narrow path. While this has the advantage of reducing the discharge amount of the resin material, if the discharge amount of the resin material cannot be adjusted accurately, the discharge amount of the resin material is likely to be excessive with respect to the narrow path. When the discharge amount becomes excessive, it is likely that the resin material will ride on the light emitting surface 30 of the LED element 3.

[0083] Therefore, while narrowing the region of the second conductive layer 11b where the resin material spreads, a region larger than the second conductive layer 11b is partitioned by a partition portion 40d formed by a resist formed on the LED substrate 10 (here, the region corresponding to the mounting region 10b of the LED element 3 is partitioned by the partition portion 40d (hatched region)). By doing so, even when the discharge amount of the resin material is relatively excessive with respect to the narrow path, it is possible to effectively suppress the resin material from riding on the light emitting surface 30 of the LED element 3.

[0084] Also, in FIGS. 5D and 5E, an extension portion 13 continuous with the mounting region 10b is formed on the LED substrate 10. By discharging the resin material onto the extension portion 13, it is possible to more effectively suppress the resin material from riding on the light emitting surface 30 of the LED element 3. When the LED substrate 10 is made of a ceramic material, since the spreading of the resin is suppressed more than that of a metal material, it is desirable to configure the extension portion 13 and the second conductive layer 11b to be close to each other. Specifically, it is desirable to arrange them such that the shortest distance between the extension portion 13 and the second conductive layer 11b is 2 mm or less.

[0085] 〈2〉 In each of the above-described embodiments, the extension portion 13 is formed on the second conductive layer 11b. However, when the resin material can be directly supplied onto the metal bonding layer 5, the extension portion 13 does not necessarily have to be formed. For example, when a mounting portion 12 that is sufficiently larger than the mounting area of the LED element 3 is formed and a sufficient amount of resin is supplied to cover the entire second conductive layer 11b, it is not always necessary to form the extension portion 13.

[0086] 〈3〉 The configuration of the light source device 1 described above is merely an example, and the present invention is not limited to each of the illustrated configurations.

Explanation of Signs

[0087] 1: Light source device 2a, 2b: Substrate electrode 3: LED element 4: Wire wiring 5: Metal bonding layer 6: Resin layer 10: LED substrate 10a: Main surface 10b: Mounting area 11: Conductive layer 11a: First conductive layer 11b: Second conductive layer 12: Mounting part 12a: Buffer area 13: Extension part 14: Slit 30: Light emitting surface 31a: First electrode 31b: Second electrode 40a, 40b, 40c, 40d: Partition part d1, d2: Distance

Claims

1. An LED substrate having a first conductive layer and a second conductive layer made of a metal material provided adjacent to each other on a main surface; An LED element placed on the second conductive layer, having a first electrode provided on a light emitting surface and a second electrode provided on a surface opposite to the light emitting surface; A wire wiring connecting the first electrode of the LED element and the first conductive layer; A metal bonding layer containing at least silver, formed between the LED element and the second conductive layer on the second conductive layer; A resin layer formed along the periphery of the LED element and covering the surface of the metal bonding layer; A light source device, characterized in that, in a direction in which the wire wiring extends, the resin layer is formed in a narrow path along the side surface of the LED element between the LED element and an end portion of the second conductive layer or a partition portion provided on the second conductive layer.

2. The surface of the resin layer gradually decreases in height with respect to the main surface of the LED substrate as the distance from the LED element increases, and is parallel to the side surface of the LED element, and in a cross section when cut by a plane passing through the LED element, it exhibits a linear or concave shape. The light source device according to claim 1.

3. A mounting portion formed within a region surrounded by the LED element, an end portion of the second conductive layer, or a partition portion provided on the second conductive layer when viewed in the normal direction of the main surface of the LED substrate with the LED element placed thereon; The light source device according to claim 1 or 2, further comprising an extension portion that extends outward from the mounting portion in a direction away from the LED element as viewed from the LED element.

4. The light source device according to claim 3, characterized in that the partition portion is made of a material having a smaller surface free energy than the metal material forming the second conductive layer.

5. The light source device according to claim 3, characterized in that the partition portion is provided so as to partition a partial region on the first conductive layer, and the wire wiring is connected to the region partitioned by the partition portion.

6. The light source device according to claim 3, characterized in that the area of the extension portion is smaller than the mounting area of the LED element.

7. The light source device according to claim 3, characterized in that a plurality of the extension portions are provided corresponding to one mounting portion.

8. The light source device according to claim 1 or 2, characterized in that at least a portion of the second conductive layer located between the LED element and the first conductive layer is covered by the resin layer.

Images