Light source device

Abstract

Provided is a light source device in which occurrence of migration is suppressed without requiring a complicated structure.　This light source device comprises: an LED substrate having a first conductive layer and a second conductive layer that are provided adjacent to each other on a main surface and comprise a metal material; an LED element that has a first electrode provided on a light emission surface and a second electrode provided on a surface on the reverse side from the light emission surface, and is mounted above the second conductive layer; wire wiring that connects the first electrode of the LED element and the first conductive layer; a metal joining layer that is formed between the LED element and the second conductive layer on the second conductive layer, and contains at least silver; and a resin layer that is formed along the periphery of the LED element and covers the surface of the metal joining layer. 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 of the second conductive layer or a partition part provided on the second conductive layer.

Description

light source device

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

[0002] A light source device equipped with an LED element is generally realized by mounting the LED element on a mounting substrate appropriate for the application. In many cases, silver (Ag) paste is used as the material used when mounting the LED element on the substrate, taking into consideration factors such as 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 near the electrode (anode) of the LED element (sometimes called "ion migration"). Specifically, migration here refers to a phenomenon in which silver contained in the silver paste comes into contact with moisture present around the LED element near the electrode, and when a voltage is applied, silver or silver oxide precipitates.

[0004] While voltage is applied to the LED element, as long as silver or moisture is present, this migration continues to precipitate silver or silver oxide. The material precipitated near one electrode of the LED element gradually spreads in a stain-like pattern toward the other electrode, and ultimately, the material precipitated by migration may short-circuit the electrodes. A short circuit between the electrodes can lead to failure or destruction of the LED element, significantly affecting reliability. Therefore, methods to suppress the occurrence of the above-mentioned migration are being investigated.

[0005] Patent No. 6139427

[0006] For example, Patent Document 1 above describes a method for suppressing the occurrence of migration by suppressing the irradiation of silver paste with light emitted from an LED element that is returned to the LED element (also referred to as "returned light"). The method described in Patent Document 1 above aims to suppress the occurrence of migration by suppressing the ionization of silver that occurs when light emitted from the LED element is irradiated onto the silver paste.

[0007] However, the structure described in Patent Document 1 accommodates the LED element on a substrate on which the LED element is mounted, and fills the recess with a light-blocking material to block part of the light traveling toward the silver paste. 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 the recess with an appropriate amount of light-blocking material may complicate the structure of the light source device, increase the number of manufacturing steps and manufacturing costs, and further require more precise control in the mounting process of the LED element. For these reasons, the structure described in Patent Document 1 is difficult to adopt in practice.

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

[0010] The light source device of the present invention comprises an LED substrate having a first conductive layer and a second conductive layer made of a metal material disposed adjacent to each other on a main surface thereof; an LED element mounted on the second conductive layer, the LED element having a first electrode disposed on the light emitting surface and a second electrode disposed on the surface opposite to the light emitting surface; a wire wiring connecting the first electrode of the LED element to the first conductive layer; a metal bonding layer containing at least silver 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, wherein the resin layer is formed in a narrow path along the side of the LED element between the LED element and an end of the second conductive layer or a partition portion disposed on the second conductive layer in the extending direction of the wire wiring.

[0011] In this specification, the term "direction in which the wire wiring extends" refers to the direction along the line connecting the connection points where the respective ends of the wire wiring are connected. In other words, whether the wire wiring extends straight in reality or is bent or meandering, the "direction in which the wire wiring extends" is determined based on the positions of the connection points where the wire wiring is connected.

[0012] In this specification, the term "narrow path" refers to a gap formed on a region of the second conductive layer and remaining between the LED element and the end of the second conductive layer or a partition provided on the second conductive layer. This refers to a region where the distance between the LED element and the end of the second conductive layer or the partition provided on the second conductive layer is 3 mm or less. The narrow path width is preferably 2 mm or less, and more preferably 1 mm or less, because the resin material tends to spread along the narrow path more easily. By forming such a narrow path, even a small amount of resin material can easily form a resin layer in the desired region, and the surface of the metal bonding layer can easily be covered with the resin layer. The narrow path is not limited to a path of a predetermined width. It is also envisioned that when an LED element is placed on a mounting portion on the second conductive layer, the narrow path can be part of the mounting portion that appears around the LED element when viewed from a direction perpendicular to the light-emitting surface of the LED element.

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

[0014] As mentioned above, migration can occur not only when silver is irradiated with light, but also when the silver comes into contact with moisture around the LED element, but it is easier to prevent moisture from coming into contact with the silver than to block light, because the light absorption rate of materials used for light blocking generally differs depending on the wavelength of the light.

[0015] In the light source device having the above configuration, the metal bonding layer formed around the LED element, i.e., the portion where silver may come into contact with moisture, is covered with a resin layer, which prevents contact between the metal bonding layer and moisture present around the LED element, thereby suppressing the occurrence of migration.

[0016] Here, we will explain how to mount an LED element on a flat second conductive layer provided on the main surface of the LED substrate, fill the gap between the LED element and the second conductive layer, and cover the surface of the metal bonding layer that extends around the LED element with a resin layer.

[0017] The resin layer is formed by supplying a resin material before solidification to the surface of the metal bonding layer and solidifying it by heat treatment or ultraviolet light irradiation. In this case, the liquid resin material may be applied directly to the surface of the metal bonding layer, but if the LED elements are thin and small, it is difficult to apply the resin material directly to the surface of the metal bonding layer, and if the LED elements are arranged densely, it is even more difficult to apply the resin material directly to the surface of the metal bonding layer.

[0018] The inventors then noticed that the surface free energy on conductive layers and metal bonding layers made of metal materials is relatively high, making it easy for resin materials to wet and spread before solidification, and came up with the idea of ​​utilizing this property.

[0019] In the light source device having the above configuration, the resin naturally spreads by supplying a sufficient amount of unsolidified resin material to any position on the second conductive layer without directly applying it to the metal bonding layer. By limiting the area where the resin spreads (the area where the resin material and the second conductive layer come into contact), it is possible to limit the spread of the resin to undesired areas. For example, the resin material can be supplied to the entire surface of the metal bonding layer around the LED element.

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

[0021] This eliminates the need to increase the amount of resin material supplied to the second conductive layer, preventing the resin material from spreading to undesired areas. Furthermore, by spreading the resin material through a narrow path, it is easy to prevent the resin material from running onto the light-emitting surface of the LED element. In other words, by ensuring that the light-emitting surface of the LED element is not covered with resin material, it is possible to prevent light (e.g., ultraviolet light) emitted from the light-emitting surface from being absorbed by the resin material.

[0022] In addition to the above studies, the present inventors also considered the presence of wire wiring when examining the path along which the resin material spreads, and also examined the structure of the second conductive layer around the LED element.

[0023] Wire wiring is generally made of metal material for reasons of conductivity, flexibility, ease of processing, and the like. Therefore, if the wire wiring comes into contact with the resin material before solidification, there is a risk of the resin material being absorbed. If the wire wiring absorbs the resin material, the resin material may unintentionally wet and spread onto the light-emitting surface of the LED element, potentially reducing the brightness of the LED element. Therefore, while depending on the order of the manufacturing process, it is necessary to avoid contact between the wire wiring and the resin material, taking into consideration the need to be able to accommodate any manufacturing process. However, when attempting to apply the resin material covering 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 light source device described above forms narrow paths along the area where the resin material is desired to spread, and then forms a resin layer in the narrow paths. Therefore, the resin material spreads along the narrow paths, and even a small amount can easily form a resin layer that covers the surface of the metal bonding layer. Furthermore, because the resin layer is formed along the narrow paths, the resin layer is less likely to swell, making it easier to avoid contact between the wire wiring and the resin material.

[0025] The resin layer can be easily formed by forming a narrow path along the side surface of the LED element, not necessarily 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 along the entire periphery of the LED element.

[0026] The light source device having the above-described configuration is structured so that the wire wiring is less likely to come into contact with the resin material that wets and spreads on the surfaces of the second conductive layer and the metal bonding layer, which makes it easier to prevent the resin material for forming the resin layer from running down the wire wiring and unintentionally wetting and spreading on the light-emitting surface.

[0027] When the wire wiring is bonded at one end to the light-emitting surface and moves toward the first conductive layer, it passes a position higher than the LED element relative to the main surface of the LED substrate, and then the other end is bonded at a predetermined position on the first conductive layer. Therefore, the wiring is necessarily routed to avoid the resin material near the LED element. However, due to the operation of the bonding process, the height from the main surface of the LED substrate is likely to change near the positions corresponding to the exact middle of each bonding position, making it easy for the wire wiring and the second conductive layer to become close to each other. Furthermore, it is possible that undesired external stress could cause the wire wiring to become close to the second conductive layer. In this case, if the wire wiring becomes too close to the second conductive layer, a short circuit may occur. Therefore, it is desirable to interpose a resin layer between the second conductive layer and the wire wiring.

[0028] From this point of view, it is also preferable that, in the direction in which the wire wiring extends, a resin layer be formed in a narrow path along the side of the LED element between the LED element and the end of the second conductive layer or 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 may be such that its height relative to the main surface of the LED substrate gradually decreases as it moves away from the LED element, and may be parallel to the side surface of the LED element, and may have a linear or concave cross section when cut along a plane passing through the LED element.

[0030] By adopting the above-described configuration, it is possible to more effectively prevent contact between the uncured resin material for forming the resin layer and the wire wiring. Although it depends on the viscosity of the resin material, if a resin material with a relatively low viscosity is used and the resin material is supplied as is along the narrow path without using a formwork or the like, the resin layer is likely to be naturally formed to have the above-described shape.

[0031] The light source device may include: a mounting portion on which the LED element is mounted and which is formed within an area surrounded by an end 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 mounted thereon; and an extension portion which, when viewed from the LED element, extends outward from the mounting portion in a direction away from the LED element.

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

[0033] In addition, in the above light source device, the partition portion may be provided to partition a portion of an area on the first conductive layer, and the wire wiring may be connected to the area partitioned by the partition portion.

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

[0035] Furthermore, depending on the device that supplies the resin material before solidification to form the resin layer, the discharge port that supplies the resin material may be large, making it difficult to accurately supply the resin material to a narrow area. Therefore, if an extension portion that is connected to the mounting area is formed as in the above configuration, supplying the resin material becomes relatively easy. Furthermore, by forming the extension portion with a specified size and shape, it can also be used as an alignment to detect the position where the resin material is to be supplied.

[0036] Furthermore, it is more preferable that the extension portion be formed so as to be connected to only a portion of the mounting area. If the extension portion is formed around the entire periphery of the mounting area, the supplied resin material will spread outside the mounting area, making it difficult to control the spreading of the resin. Specifically, it is more preferable that the distance between the extension portion and the mounting area be kept to 50% or less of the periphery of the mounting area.

[0037] In the light source device, it is preferable that the area of ​​the extension portion is smaller than the area where the LED element is mounted.

[0038] In the light source device, a plurality of the extension portions may be provided corresponding to one of the mounting portions.

[0039] In the 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] The wire wiring may bend significantly between the LED element and the first conductive layer due to, for example, deformation caused by contact during assembly, by the operation during bonding, or by long-term application of gravity or heat, etc. Therefore, 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, causing a short circuit between the first conductive layer and the second conductive layer.

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

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

[0043] 5D is a schematic diagram of an embodiment of a light source device as a whole when viewed from the +Z side. FIG. 5C is a diagram schematically showing adjacent conductive layers. FIG. 5D is an enlarged view of region R1 in FIG. 2. FIG. 5C is a diagram of a state in which the resin layer formed on the first conductive layer in FIG. 3A has been removed. FIG. 5D is a cross-sectional view taken along A-A in FIG. 3A. FIG. 5D is a schematic cross-sectional view of an embodiment of a light source device. FIG. 5D is a schematic diagram of another embodiment of a light source device when viewed from the Z direction. FIG. 5C is a schematic diagram of another embodiment of a light source device when viewed from the Z direction. FIG. 5D is a cross-sectional view taken along B-B in FIG. 5D.

[0044] The light source device of the present invention will be described below with reference to the drawings. Note that the drawings are all schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily match the actual dimensional ratios and numbers.

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

[0046] 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, wire wiring 4, a conductive layer 11, a partition 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 is shown in which a plurality of LED elements 3, a plurality of wire wiring 4, and a plurality of conductive layers 11 are provided, but the light source device 1 may also 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 perpendicular to the XY plane, i.e., a direction normal to 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 defined as the Y direction.

[0048] Furthermore, when expressing a direction, if a distinction is made between positive and negative directions, the direction is written with a positive or negative sign, such as "+Z direction" or "-Z direction," and when a direction is expressed without distinguishing between positive and negative directions, it is simply written as "Z direction."

[0049] As shown in Figure 4A, the LED element 3 is an element having a structure in which a pair of electrodes (31a, 31b) are formed on opposing surfaces in the Z direction, and 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 surface on the +Z side on which the first electrode 31a of the LED element 3 is formed is a light emitting surface 30 for extracting light generated inside an area different from the first electrode 31a. Note that, with respect to the LED element 3 employed in the present invention, it is optional as to which wavelength band of light the LED element 3 emits.

[0051] The wire 4 is a metal wire that connects the first electrode 31a and the first conductive layer 11a of the LED element 3. The wire 4 is made of, for example, gold (Au).

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

[0053] As shown in Figure 2, a pair of adjacent conductive layers 11 connected by the LED element 3 and the wire wiring 4 correspond 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 whether each conductive layer 11 corresponds to the first conductive layer 11a or the second conductive layer 11b is not uniquely determined, but is determined depending on which LED element 3 is being focused on.

[0055] The conductive layer 11 is a layer made of a conductive metal material, and specific examples thereof include copper (Cu), gold (Au), nickel (Ni), palladium (Pd), or alloys thereof.

[0056] 4A, adjacent conductive layers 11 forming a pair of a first conductive layer 11a and a second conductive layer 11b are formed to be separated by a distance d1. The distance d1 needs to be set 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 are not short-circuited by deposits or the like.

[0057] Furthermore, if the distance d1 is too large, problems may arise such as electrical resistance due to the wire wiring 4 and bending of the wire wiring 4. In view of the above, 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] Partitions (40a, 40b) are formed on the conductive layer 11 to prevent the resin material forming the resin layer 6 (described later) from spreading. The partitions 40a, together with the end of the second conductive layer 11b, are structures that surround the mounting area 12 (the area surrounded by the dashed line in FIG. 3B ) where the LED element 3 is mounted. The mounting area 12 here refers to the area of ​​the second conductive layer 11b within the mounting area defined as an area 20% larger than one side of the LED element 3 when viewed in the Z direction. The partitions 40b here are structures that form an extension area 13 (the area surrounded by the dashed line in FIG. 3B ) that is smaller in area than the mounting area of ​​the LED element 3 and that supplies the resin material forming the resin layer 6.

[0059] The partitions (40a, 40b) are structures made of a material with a surface free energy lower than that of a metal material. Examples of materials with a surface free energy lower than that of a metal material include resist and resin. Note that each region shown in FIG. 3B is a region defined by the partitions (40a, 40b) and the end of the second conductive layer 11b, and is formed to define the region of the mounting portion 12. However, for convenience of illustration, the dashed lines and dashed-dotted lines are shown slightly shifted inward from the actual regions.

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

[0061] Furthermore, in this embodiment, one mounting section 12 is connected to one expansion section 13 , but multiple mounting sections 12 may be connected to one expansion section 13 .

[0062] 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 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 to which the silver paste has been applied, the silver paste is pressed 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 as if being pushed out around the LED element 3. The spread silver paste is solidified by a heating treatment, a drying treatment, or the like, and a 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] 3A to 4A, the LED element 3 is mounted at a position spaced a fixed distance d2 from the end of the second conductive layer 11b. This mounting method effectively prevents excess silver paste from spilling out from between the LED element 3 and the conductive layer 11 and flowing between the first conductive layer 11a and the second conductive layer 11b, which could cause a short circuit. In this embodiment, the LED element 3 is positioned so that the +Y side of the LED element 3 is spaced a distance d2 from the end of the second conductive layer 11b, and a buffer region 12a is formed around the LED element 3, extending along each side of the LED element 3.

[0065] 4A , it is anticipated that the wire wiring 4 may droop toward the LED substrate 10 as it moves toward the first conductive layer 11a, particularly after passing through the side surface of the LED element 3. Therefore, from the viewpoint of minimizing contact of the wire wiring 4 with the resin material before solidification, the distance d2 is configured to be smaller than the distance d1.

[0066] The LED element 3 of this embodiment is similarly positioned on the -X side of the LED element 3 so as to be spaced a distance d2 from the end of the second conductive layer 11b, but the distance between the LED element 3 on the -X side and the end of the second conductive layer 11b 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 hardened metal bonding layer 5 around the LED element 3 and the second conductive layer 11b located on the +Y side of the LED element 3 in the direction in which the wire wiring 4 passes. The resin layer 6 is a moisture-resistant layer. The material constituting the resin layer 6 may be a hydrophobic resin such as silicone resin. Note that if the wire wiring 4 passes at a position sufficiently distant from the second conductive layer 11b, the portion of the second conductive layer 11b where the wire wiring 4 passes on the +Z side does not need to be entirely covered with the resin layer 6. Furthermore, whether or not to form the resin layer 6 on the portion of the second conductive layer 11b where the wire wiring 4 does not pass on the +Z side is optional, except for the portion where the metal bonding layer 5 is formed. For example, the resin layer 6 may be formed to cover the periphery of the LED element 3 and at least partially on the partitions (40a, 40b).

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

[0069] In the resin layer 6, the resin material dispensed onto the extension 13 of the second conductive layer 11b in the state shown in FIG. 3B spreads over the second conductive layer 11b, which is made of a metal material with a relatively high surface free energy. After spreading to the periphery of the LED element 3, the resin material spreads over the surface of the metal bonding layer 5, which, like the second conductive layer 11b, has a relatively high surface free energy, reaching the side surfaces of the LED element 3. Because the resin material actively spreads over the second conductive layer 11b and the metal bonding layer 5 rather than over the side surfaces 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. Furthermore, because a narrow path is formed between the LED element 3 and the end of the second conductive layer 11b or the partitions (40a, 40b) provided on the second conductive layer 11b, the resin material spreads along the narrow path, making it less likely to spread to undesired areas.

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

[0071] 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 if a sufficient distance can be secured between the resin layer 6 and 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, i.e., the portion where silver may come into contact with moisture, is covered with the resin layer 6. This prevents the metal bonding layer 5 from coming into contact with moisture present around the LED element 3, thereby suppressing the occurrence of migration.

[0073] Furthermore, in the light source device 1 having the above configuration, the resin layer 6 is formed on the flat second conductive layer 11b over the entire surface of the metal bonding layer 5 that exists around the LED element 3, without forming any complex structure on the LED substrate 10. Furthermore, by appropriately adjusting the amount of resin material supplied to the second conductive layer 11b, it is possible to prevent the resin material from running onto the light emission surface 30 of the LED element 3.

[0074] Furthermore, the light source device 1 having the above configuration is structured so that the wire wiring 4 is less likely to come into contact with the resin material that wets and spreads on the surfaces of the second conductive layer 11b and the metal bonding layer 5. Therefore, it is easy to prevent the resin material for forming the resin layer 6 from running down the wire wiring 4 and unintentionally wetting and spreading onto the light emitting surface 30.

[0075] FIG. 4B is a schematic cross-sectional view illustrating the same portion as FIG. 4A of another embodiment of the light source device 1, different from the above-described configuration. As shown in FIG. 4B , a partition 40c may be formed between the first conductive layer 11a and the second conductive layer 11b. In this embodiment, as shown in FIG. 4B , the partitions (40a, 40c) are formed to cover a wider area of ​​the first conductive layer 11a and the second conductive layer 11b. This reduces contact between the wiring 4 and the first conductive layer 11a or the second conductive layer 11b, making short circuits less likely to occur. The narrow path here is formed in the gap between the LED element 3 and the partition 40c provided on the second conductive layer 11b, resulting in a narrow path narrower than the distance d2. The partition 40c in this configuration functions similarly to the partitions (40a, 40b), but they do not all need to be made of the same material.

[0076] Another embodiment will now be described.

[0077] 5A to 5D are schematic diagrams of another embodiment of the light source device 1 as viewed from the Z direction, and Fig. 5E is a cross-sectional view taken along the line B-B of Fig. 5D. For the sake of convenience, the light source device 1 described here is described on the assumption that one LED element 3 is mounted on the LED substrate 10. However, it is also naturally assumed that the light source device 1 may be applied to a case in which multiple LED elements 3 are mounted, as in the above-described embodiment.

[0078] 5A and 5B, the second conductive layer 11b may be configured with a mounting portion 12 and an extension portion 13 without providing a partition portion. The shape of the extension portion 13 is arbitrary as long as it is continuous with the region of the mounting portion 12 of the LED element 3 and extends outward beyond the region of the mounting portion 12.

[0079] 5C, the mounting portion 12 and the extension portion 13 may be formed by slits 14 provided on the second conductive layer 11b. Furthermore, the slits 14 may be replaced by a group of through holes or the like.

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

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

[0082] When forming a narrow path using the partition 40d, if the narrow path is too narrow, the resin material will easily fill the narrow path during the process of wetting and spreading the resin material before solidification. While this has the advantage of reducing the amount of resin material dispensed, if the amount of resin material dispensed cannot be accurately adjusted, the amount of resin material dispensed may be excessive for the narrow path. If the amount of resin dispensed is excessive, there is a high possibility that the resin material may run over the light-emitting surface 30 of the LED element 3.

[0083] Therefore, by narrowing the area of ​​the second conductive layer 11b where the resin material spreads, and partitioning an area larger than the second conductive layer 11b with a partition 40d formed by a resist formed on the LED substrate 10 (here, the area corresponding to the mounting area 10b of the LED element 3 is partitioned with the partition 40d (hatched area)), it is possible to effectively prevent the resin material from running onto the light emission surface 30 of the LED element 3 even if the amount of resin material discharged becomes relatively excessive for the narrow path.

[0084] 5D and 5E , an extension portion 13 connected to the mounting area 10b is formed on the LED substrate 10, and discharging the resin material onto the extension portion 13 more effectively prevents the resin material from running onto the light emission surface 30 of the LED element 3. When the LED substrate 10 is made of a ceramic material, the resin is less likely to spread when wet than when made of a metal material, so it is desirable to configure the extension portion 13 and the second conductive layer 11b so that they are close to each other. Specifically, it is desirable to arrange them so 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, but the extension portion 13 does not necessarily have to be formed if the resin material can be supplied directly onto the metal bonding layer 5. For example, if the mounting portion 12 is formed to be sufficiently larger than the mounting area of ​​the LED element 3 and a sufficient amount of resin is supplied to cover the entire second conductive layer 11b, the extension portion 13 does not necessarily have to be formed.

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

[0087] REFERENCE SIGNS LIST 1: Light source device 2a, 2b: Substrate electrodes 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 portion 12a: Buffer area 13: Extension portion 14: Slit 30: Light emission surface 31a: First electrode 31b: Second electrode 40a, 40b, 40c, 40d: Partition portion 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 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 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, and a resin layer formed along the periphery of the LED element and covering the surface of the metal bonding layer, wherein the resin layer is formed in a narrow path along the side surface of the LED element between the LED element and an end of the second conductive layer or a partition provided on the second conductive layer in a direction in which the wire wiring extends. A light source device characterized by this.

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

3. A mounting portion formed within a region surrounded by the LED element, an end of the second conductive layer, or a partition provided on the second conductive layer when viewed in the normal direction of the main surface of the LED substrate with the LED element mounted, and an extension portion extending outward from the mounting portion away from the LED element when viewed from the LED element. The light source device according to claim 1 or 2, characterized by this.

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

5. The partition 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. The light source device according to claim 3, characterized by this.

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

7. A plurality of the extension portions are provided corresponding to one mounting portion. The light source device according to claim 3, characterized by this.

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

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