Light emitting device

Abstract

Provided is a light-emitting device with which the extraction efficiency of ultraviolet light is improved. A light-emitting device that emits ultraviolet light is provided with a mounting substrate, a light-emitting element, a light-transmitting member, an inert compound, and a gas layer. The light-emitting element is disposed on the mounting surface of the mounting substrate, and has an element main surface facing the opposite side to the mounting surface, and an element side surface adjacent to the element main surface. The light-transmitting member is disposed on the mounting surface, forms an accommodation space in an area facing the mounting surface, and has a recess that constitutes at least a part of the accommodation space and can accommodate at least a part of the light-emitting element. The inert compound fills a main facing region in which the element main surface faces the first top surface of the recess, and a first sub-facing region in which a portion of the element side surface located in the vicinity of the element main surface faces the first side wall surface of the recess. The gas layer is formed in a second sub-facing region of the element-facing side surface, the second sub-facing region being located in the vicinity of the mounting substrate.

Description

Technical Field

[0001] The present invention relates to a light emitting device. Background Art

[0002] Light-emitting devices using ultraviolet-emitting light-emitting elements are used in various applications. As such light-emitting devices, for example, Patent Documents 1 and 2 disclose the following structure: an ultraviolet-emitting light-emitting element is mounted on a mounting substrate, and the ultraviolet-emitting side of the light-emitting element is covered by a dome-shaped light-transmitting member. Moreover, in the structure disclosed in Patent Document 1, the main surface of the light-emitting element on the side opposite to the mounting substrate, the entire area of ​​the side surface, and the inner side surface of the light-transmitting member are filled with a liquid sealing material that allows ultraviolet light to pass, and the sealing material is cured in a state where a gap is formed between the light-transmitting member and the mounting substrate. The gap can prevent the sealing material before curing from flowing out from between the light-transmitting member and the light-emitting element due to capillary phenomenon.

[0003] Furthermore, in the structure disclosed in Patent Document 2, a liquid carbon fluoride compound is filled between the upper surface that becomes the main surface of the light-emitting element and the inner side surface of the light-transmitting member that faces the upper surface at room temperature and pressure, and an air layer exists between the entire side surface of the light-emitting element and the inner side surface of the light-transmitting member. The liquid carbon fluoride compound is held between the main surface of the light-emitting element and the inner side surface of the light-transmitting member by the surface tension generated by the air layer, thereby preventing the liquid carbon fluoride compound from flowing out to the joint portion where the light-transmitting member is joined to the mounting substrate.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2016-127156

[0005] Patent Document 2: Japanese Patent Application Publication No. 2022-108692

[0006] In the structure disclosed in Patent Document 1, if the liquid sealing material is used at room temperature and pressure without solidifying, the liquid sealing material will flow out to the joint between the light-transmitting component and the mounting substrate, hindering the joint between the light-transmitting component and the mounting substrate, resulting in a reduction in the reliability of the joint between the light-transmitting component and the mounting substrate.

[0007] Furthermore, in the structure disclosed in Patent Document 2, ultraviolet light radiated from the entire side surface of the light-emitting element in the air layer between the entire side surface of the light-transmitting element and the inner side surface of the light-transmitting component easily reaches the joint that joins the light-transmitting component to the mounting substrate, promoting deterioration of the joint, thereby reducing the reliability of the joint. Summary of the invention

[0008] The present invention has been made in view of such a problem, and aims to provide a light emitting device that improves the reliability of a joining portion between a light-transmitting member and a mounting substrate.

[0009] One aspect of the present invention is a light-emitting device, which is an ultraviolet light-emitting device and comprises: a mounting substrate having a mounting surface; an ultraviolet light-emitting element, which is arranged on the mounting surface of the mounting substrate and has an element main surface facing the side opposite to the mounting surface and an element side surface adjacent to the element side surface; a light-transmitting member, which is arranged on the mounting surface of the mounting substrate and forms a housing space in an opposing region facing the mounting surface of the mounting substrate and has a recess that constitutes at least a part of the housing space and can house at least a part of the light-emitting element; an inactive compound, which is arranged in the housing space and is liquid at normal temperature and pressure; and a gas layer formed in the housing space. ; and a light-transmitting component bonding layer, which is arranged between the above-mentioned mounting substrate and the above-mentioned light-transmitting component, and bonds the above-mentioned mounting substrate to the above-mentioned light-transmitting component. In the present light-emitting device, the above-mentioned inactive compound is filled in a main opposing region in which the above-mentioned element main surface of the above-mentioned light-emitting element faces the first top surface of the above-mentioned recess, and a first secondary opposing region in which a portion of the above-mentioned element side surface of the above-mentioned light-emitting element located near the above-mentioned element main surface faces the first side wall surface of the above-mentioned recess, and the above-mentioned gas layer is formed in a second secondary opposing region in which a portion of the above-mentioned element side surface facing the above-mentioned light-emitting element is located near the above-mentioned mounting substrate. In a direction perpendicular to the above-mentioned mounting surface, the above-mentioned light-transmitting component bonding layer is located closer to the above-mentioned mounting substrate than the above-mentioned first secondary opposing region.

[0010] In the above-mentioned light-emitting device, an inactive compound that is liquid at normal temperature and pressure is filled in a main facing region where the main surface of the element faces the first top surface of the concave part of the light-transmitting member, and is filled in a first secondary facing region where a portion of the side surface of the element located near the main surface of the element faces the first side wall surface of the concave part of the light-transmitting member. In addition, a gas layer is formed in a second secondary facing region facing a portion of the side surface of the element located near the mounting substrate. According to the above content, the inactive compound filled in the first secondary facing region is suppressed from flowing out and reaching the light-transmitting member bonding layer that bonds the light-transmitting member to the mounting substrate, thereby preventing the bonding of the light-transmitting member to the mounting substrate from being hindered by the inactive compound. In addition, ultraviolet light emitted from a portion of the side surface of the element located near the main surface of the element is incident on the light-transmitting member via the inactive compound filled in the first secondary facing region, thereby suppressing the ultraviolet light from reaching the light-transmitting member bonding layer. Therefore, the degradation of the light-transmitting member bonding layer caused by ultraviolet light is suppressed, and the reliability of the light-transmitting member bonding layer is improved.

[0011] Furthermore, in the direction perpendicular to the mounting surface, the light-transmitting component bonding layer that bonds the light-transmitting component to the mounting substrate is located closer to the mounting substrate than the first secondary opposing region, so that ultraviolet light radiated from at least a portion near the main surface of the element in the side surface of the element is not easy to reach the light-transmitting component bonding layer. Therefore, the degradation of the light-transmitting component bonding layer caused by ultraviolet light is suppressed, and the reliability of the light-transmitting component bonding layer is improved.

[0012] As described above, according to the present invention, it is possible to provide a light emitting device capable of achieving improved reliability of a joining portion between a light transmissive member and a mounting substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a cross-sectional view of the light emitting device according to Embodiment 1, taken along a plane perpendicular to the mounting substrate.

[0014] Figure 2 This is a conceptual cross-sectional view for explaining the structure of the light emitting element according to Embodiment 1.

[0015] Figure 3 yes Figure 1 An enlarged cross-sectional view of the vicinity of the second secondary facing region.

[0016] Figure 4 This is a flowchart for explaining the method for manufacturing the light-emitting device according to Embodiment 1.

[0017] Figure 5 This is a conceptual diagram for explaining the method for manufacturing the light-emitting device according to Embodiment 1.

[0018] Figure 6 This is an enlarged cross-sectional view of the vicinity of the second secondary opposing region in the second embodiment.

[0019] Figure 7 This is a cross-sectional view of the light emitting device according to Embodiment 3, taken along a plane perpendicular to the mounting substrate.

[0020] Description of Reference Numerals

[0021] 1...light-emitting device; 10...mounting substrate; 10a...mounting surface; 10b...outer periphery; 11...main body; 12...circuit pattern; 13...substrate recess; 13a...second top surface; 13b...side wall surface; 20...light-emitting element; 21, 22...electrode pads; 23...element main surface; 24...element side surface; 30...element bonding layer; 40...light-transmitting component; 41...recess; 42...first recess; 42a...first top surface; 42b...first side wall surface; 43...second recess; 43...first secondary opposing region; 43a...second top surface; 43b...second side wall surface; 44...flange; 50...light-transmitting component bonding layer; 60...inactive compound; 70...gas layer; 80...housing space; 81...main opposing region; 82...first secondary opposing region; 83...second secondary opposing region. DETAILED DESCRIPTION

[0022] Preferably, in a direction perpendicular to the mounting surface, the light-transmitting component bonding layer is located closer to the mounting surface of the mounting substrate than the active layer of the light-emitting element. In this case, ultraviolet light radiated from the active layer of the light-emitting element is incident on the light-transmitting component via the inactive compound, which inhibits the ultraviolet light from reaching the light-transmitting component bonding layer, thereby further inhibiting degradation of the light-transmitting component bonding layer caused by ultraviolet light, and further achieving improved reliability of the light-transmitting component bonding layer.

[0023] The side surface of the active layer of the light-emitting element may face the first sub-opposing region and the inactive compound. In this case, the ultraviolet light emitted from the active layer of the light-emitting element is incident on the light-transmitting component via the inactive compound, and the ultraviolet light is prevented from reaching the light-transmitting component bonding layer, thereby further preventing the degradation of the light-transmitting component bonding layer caused by the ultraviolet light, and further improving the reliability of the light-transmitting component bonding layer.

[0024] The side surface of the active layer of the light-emitting element faces the second sub-opposing region and faces the gas layer. In this case, the distance between the inactive compound filled in the first sub-opposing region and the light-transmitting component bonding layer becomes longer, so even if the inactive compound flows out, it can be prevented from reaching the light-transmitting component bonding layer, further achieving the improvement of the reliability of the light-transmitting component bonding layer.

[0025] Preferably, the minimum facing distance of the second sub-opposing region is more than twice the facing distance of the first sub-opposing region. In this case, the distance between the inactive compound filled in the first sub-opposing region and the light-transmitting component bonding layer becomes longer, so even if the inactive compound flows out, it can be prevented from reaching the light-transmitting component bonding layer, further achieving the improvement of the reliability of the light-transmitting component bonding layer.

[0026] Preferably, the above-mentioned recess has: a first recess having the above-mentioned first top surface and the above-mentioned first side wall surface; and a second recess located on the opening side of the above-mentioned first recess and having a second top surface adjacent to the above-mentioned first side wall surface and a second side wall surface adjacent to the above-mentioned second top surface, the above-mentioned first secondary facing region is a region where a portion of the above-mentioned element side surface of the above-mentioned light-emitting element located near the above-mentioned element main surface faces the above-mentioned first side wall surface of the above-mentioned recess, and the above-mentioned second secondary facing region is a region where a portion of the above-mentioned element side surface of the above-mentioned light-emitting element located near the above-mentioned mounting substrate faces the above-mentioned second side wall surface of the above-mentioned recess. In this case, a step is formed at the boundary between the first recess and the second recess, so that the inactive compound filled in the first secondary facing region can be suppressed from reaching the light-transmitting component bonding layer, and the reliability of the light-transmitting component bonding layer can be further improved.

[0027] The light-transmitting member bonding layer preferably includes a silicone resin. Since both the light-transmitting member and the mounting substrate have high adhesion, the reliability of the light-transmitting member bonding layer can be further improved.

[0028] (Implementation Method 1)

[0029] 1. Structure of the Light-Emitting Device 1

[0030] Reference Figure 1 The structure of the light emitting device 1 of this embodiment is described. The light emitting device 1 is a light emitting element package that contains the ultraviolet light emitting element 20 as a main component. The ultraviolet light emitting device 1 includes a mounting substrate 10, a light emitting element 20, an element bonding layer 30, a light transmissive member 40, a light transmissive member bonding layer 50, an inactive compound 60, and a gas layer 70.

[0031] The mounting substrate 10 is a substrate having a mounting surface 10a and for mounting the light emitting element 20 on the mounting surface 10a. In this embodiment, the mounting substrate 10 is formed in a flat plate shape. However, the mounting substrate 10 may be formed in a box shape having a recessed portion.

[0032] The mounting substrate 10 includes a main body 11 and a circuit pattern 12. The main body 11 of the mounting substrate 10 is formed in a flat plate shape, for example. The main body 11 includes at least one ceramic selected from a group such as AlN, Al2O3, SiC, and Si2N4. The circuit pattern 12 includes a first pattern portion 12a exposed on one surface of the main body 11 of the mounting substrate 10, and a second pattern portion 12a exposed on the other surface of the main body 11 of the mounting substrate 10. Figure 1 The mounting substrate 10 includes a second pattern portion 12b exposed on the lower surface of the mounting substrate 10 and a connecting pattern portion (not shown) connecting the first pattern portion 12a and the second pattern portion 12b. The surface of the mounting substrate 10 on the side of the first pattern portion 12a constitutes the mounting surface 10a. The surface of the mounting substrate 10 on the side of the second pattern portion 12b constitutes an exposed surface exposed to the outside. The second pattern portion 12b constitutes a portion electrically connected to an external mounting substrate not shown.

[0033] The light emitting element 20 is composed of a group III nitride and emits ultraviolet light of a predetermined wavelength. The light emitting element 20 is a light emitting element that emits ultraviolet light with a wavelength of 100 nm to 400 nm. In particular, the light emitting element 20 is a light emitting element that emits deep ultraviolet light with a wavelength of 100 nm to 280 nm (UVC band). The thickness of the light emitting element 20 ( Figure 1 The thickness in the vertical direction) is greater than 1 μm.

[0034] The light emitting element 20 is mounted on the mounting surface 10a of the mounting substrate 10. In this embodiment, the light emitting element 20 is a flip-chip element having electrode pads 21 and 22 on the surface close to the mounting substrate 10. Therefore, the electrode pads 21 and 22 of the light emitting element 20 are located on the mounting surface 10a side of the mounting substrate 10, and are electrically connected to the first pattern portion 12a of the circuit pattern 12 of the mounting substrate 10 via the element bonding layer 30.

[0035] In this embodiment, the light emitting element 20 includes: a light emitting element 20 facing the side opposite to the mounting surface 10a of the mounting substrate 10 ( Figure 1 The main surface 23 of the element is formed into a plane shape parallel to the mounting surface 10a of the mounting substrate 10. The main surface 23 of the element is formed into a rectangular shape. The arithmetic mean roughness (arithmetic mean deviation; the same below) Ra of the main surface 23 of the element is 0.1nm to 100000nm.

[0036] The element side surface 24 is adjacent to each side of the outer periphery of the element main surface 23. The element side surface 24 has a surface in a direction substantially perpendicular to the mounting surface 10a of the mounting substrate 10. In other words, the element side surface 24 has four surfaces adjacent to each side of the element main surface 23. The arithmetic mean roughness Ra of the element side surface 24 of the light emitting element 20 is 0.1 nm to 100000 nm.

[0037] In the light emitting element 20, the angle formed by the element main surface 23 and the element side surface 24 is in the range of 80° to 100°, preferably 90°, throughout the entire periphery of the element main surface 23. Furthermore, the light emitting element 20 is formed in a shape that has no gaps such as a defect or a depression at the boundary between the element main surface 23 and the element side surface 24 throughout the entire periphery of the element main surface 23.

[0038] The element bonding layer 30 bonds the first pattern portion 12a of the circuit pattern 12 of the mounting substrate 10 to the electrode pads 21 and 22 of the light emitting element 20. The material of the element bonding layer 30 includes, for example, AuSn, Au, Ag, Cu, Al, and SAC.

[0039] The light-transmitting member 40 is disposed on the mounting surface 10a side of the mounting substrate 10. Specifically, the light-transmitting member 40 is bonded to the outer periphery of the mounting surface 10a of the mounting substrate 10 via the light-transmitting member bonding layer 50. The light-transmitting member 40 is a sealing member that forms a housing space 80 in a region facing the mounting surface 10a of the mounting substrate 10. The housing space 80 houses the light-emitting element 20 and the like.

[0040] The light-transmitting member 40 may be made of a material that transmits ultraviolet light of a light-emitting wavelength, and may be formed of glass, for example. For example, as an example of glass, the light-transmitting member 40 may be formed by including at least one selected from the group consisting of quartz, borosilicate, sapphire, fluoride, silicone resin, metaphosphate, etc. When the light-transmitting member 40 is quartz, the refractive index of the light-transmitting member 40 is 1.45.

[0041] Here, in the vertical direction perpendicular to the mounting surface 10a of the mounting substrate 10, the bonding position where the light-transmitting member 40 is bonded to the mounting substrate 10 (i.e., the position of the outer peripheral edge portion 10b of the mounting substrate 10 to which the flange portion 44 of the light-transmitting member 40 is bonded) is located on the mounting surface 10a side of the mounting substrate 10 relative to the element principal surface 23 of the light-emitting element 20. Furthermore, in the vertical direction perpendicular to the mounting surface 10a of the mounting substrate 10, the bonding position where the light-transmitting member 40 is bonded to the mounting substrate 10 is located on the mounting surface 10a side of the mounting substrate 10 relative to the position of the active layer 92b of the light-emitting element 20.

[0042] In this embodiment, the bonding position where the light-transmitting member 40 is bonded to the mounting substrate 10 is arranged along the surface of the mounting surface 10a of the mounting substrate 10, and the active layer 92b is arranged at a distance from the mounting surface 10a. By configuring in this way, as described above, the bonding position where the light-transmitting member 40 is bonded to the mounting substrate 10 is located closer to the mounting surface 10a of the mounting substrate 10 than the position of the active layer 92b of the light-emitting element 20 ( Figure 1 on the lower side of the ).

[0043] The light-transmitting member 40 has a convex lens shape, for example. That is, the outer surface of the light-transmitting member 40 is formed into a convex curved surface shape. The light-transmitting member 40 is formed into a convex lens shape, thereby being able to output the ultraviolet light emitted by the light-emitting element 20 mainly in a direction perpendicular to the mounting substrate 10 .

[0044] The light-transmitting member 40 has a recess 41 constituting at least part of the housing space 80 on the surface facing the mounting surface 10a of the mounting substrate 10. The recess 41 is configured to accommodate at least part of the light-emitting element 20. In this embodiment, the recess 41 is configured to accommodate the entire light-emitting element 20. In other words, the housing space 80 is formed between the recess 41 of the light-transmitting member 40 and the mounting surface 10a of the mounting substrate 10.

[0045] The recess 41 has a first recess 42 and a second recess 43. The recess 41 forms a stepped recess by the first recess 42 and the second recess 43. Alternatively, the recess 41 may form a stepped recess having three or more steps.

[0046] The first recess 42 is located in the center of the surface of the light-transmitting member 40 facing the mounting surface 10a of the mounting substrate 10. The first recess 42 is configured to accommodate a portion of the light-emitting element 20. The depth of the first recess 42 is shorter than the height of the light-emitting element 20. In this embodiment, the depth of the first recess 42 is about half to two-thirds of the thickness of the light-emitting element 20, and Figure 3 The depth D1 of the first recess 42 shown is 10 μm to 1000 μm. The first recess 42 includes a first top surface 42 a and a first side wall surface 42 b.

[0047] The first top surface 42a is formed in a planar shape parallel to the mounting surface 10a of the mounting substrate 10. The first top surface 42a is formed in a rectangular shape. The first top surface 42a is arranged to face the element main surface 23 of the light emitting element 20. In detail, the first top surface 42a is formed in parallel with the element main surface 23 of the light emitting element 20, and is arranged at a predetermined distance from the element main surface 23. Therefore, a main facing region 81 is formed in which the first top surface 42a of the first recess 42 faces the element main surface 23 of the light emitting element 20.

[0048] The first side wall surface 42b is adjacent to each side of the outer periphery of the first top surface 42a. The first side wall surface 42b has a surface that is substantially perpendicular to the mounting surface 10a of the mounting substrate 10. In other words, the first side wall surface 42b has four surfaces that are adjacent to each side of the first top surface 42a. Each surface of the first side wall surface 42b is adjacent to a portion of the element side surface 24 of the light emitting element 20 that is located near the element main surface 23 ( Figure 1The first sidewall surface 42b of the first recess 42 is formed in parallel with the portion of the element side surface 24 located near the element main surface 23 and is arranged at a predetermined distance from the portion of the element side surface 24 located near the element main surface 23. Figure 1 The first sub-opposing area 82 is opposite to the upper side of the area.

[0049] The second recess 43 is located on the opening side of the first recess 42, has an opening that expands the opening of the first recess 42, and has a top surface shallower than the first recess 42. The second recess 43 is configured to accommodate other parts of the light emitting element 20. The depth of the second recess 43 is shorter than the height of the light emitting element 20. In this embodiment, the depth of the second recess 43 is about half the thickness of the light emitting element 20, and Figure 3 The depth D2 of the second recess 43 shown is 10 μm to 1000 μm. The second recess 43 includes a second top surface 43 a and a second side wall surface 43 b.

[0050] The second top surface 43a is formed in a plane parallel to the mounting surface 10a of the mounting substrate 10. The second top surface 43a is adjacent to the first side wall surface 42b of the first recess 42. The outer peripheral shape of the second top surface 43a can also be rectangular or circular. The second top surface 43a is formed in an annular shape. The second top surface 43a is arranged to face the mounting surface 10a of the mounting substrate 10 and is arranged to be spaced a predetermined distance from the mounting surface 10a.

[0051] The second side wall surface 43b is adjacent to the outer periphery of the second top surface 43a. The second side wall surface 43b is at an angle relative to the mounting surface 10a of the mounting substrate 10. For example, the second side wall surface 43b forms an inclined surface at an acute angle relative to the mounting surface 10a. The second side wall surface 43b is adjacent to the portion of the element side surface 24 of the light emitting element 20 located near the mounting substrate 10 ( Figure 1 The second sidewall surface 43b of the second recess 43 faces the portion of the element side surface 24 near the mounting substrate 10 and is arranged at a predetermined distance from the portion of the element side surface 24 near the mounting substrate 10. Therefore, a space is formed so that the second sidewall surface 43b of the second recess 43 is aligned with the portion of the element side surface 24 near the mounting substrate 10 ( Figure 1 A second sub-opposing area 83 facing the lower side of the area).

[0052] The light-transmitting member bonding layer 50 is disposed between the outer periphery 10b of the mounting surface 10a of the mounting substrate 10 and the flange portion 44 forming the outer periphery of the light-transmitting member 40, and bonds the mounting surface 10a of the mounting substrate 10 to the light-transmitting member 40. The light-transmitting member bonding layer 50 is formed by including at least one selected from the group consisting of silicone resin, epoxy resin, fluororesin, solder, silane, glass, brazing material, etc. In the first embodiment, the outer periphery 10b and the mounting surface 10a are located on the same plane.

[0053] As described above, in the vertical direction Y perpendicular to the mounting surface 10a of the mounting substrate 10, the bonding position where the light-transmitting member 40 is bonded to the mounting substrate 10 is located closer to the mounting surface 10a of the mounting substrate 10 than the position of the active layer 92b of the light-emitting element 20 ( Figure 1 In other words, the light-transmitting member bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the first secondary opposing region 82. Moreover, the light-transmitting member bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the active layer 92b.

[0054] Therefore, even if the light-transmitting component bonding layer 50 uses a material that is not very durable to ultraviolet light relative to the wavelength of light emission, the impact is minimal. Therefore, the above-mentioned cheap material can be applied to the light-transmitting component bonding layer 50. Of course, the light-transmitting component bonding layer 50 can also use a material with high durability to ultraviolet light, such as silicone resin.

[0055] The inactive compound 60 is arranged in the housing space 80 formed by the mounting substrate 10 and the light-transmitting member 40. The inactive compound 60 is arranged in the main opposing region 81 and the first sub-opposing region 82 in the housing space 80. In other words, the inactive compound 60 is filled in the main opposing region 81 where the first top surface 42a of the first recess 42 faces the element main surface 23 of the light-emitting element 20. Therefore, the inactive compound 60 contacts the first top surface 42a of the first recess 42 and contacts the element main surface 23 of the light-emitting element 20.

[0056] Furthermore, the inactive compound 60 is filled in the first sub-opposing region 82 where the first side wall surface 42b of the first recess 42 faces a portion of the element side surface 24 of the light-emitting element 20 located near the element main surface 23. Therefore, the inactive compound 60 contacts the first side wall surface 42b of the first recess 42 and contacts a portion of the element side surface 24 of the light-emitting element 20 located near the element main surface 23. Furthermore, the side surface of the active layer 92b of the light-emitting element 20 faces the first sub-opposing region 82. In other words, the side surface of the active layer 92b of the light-emitting element 20 faces the inactive compound 60.

[0057] The inactive compound 60 is liquid at normal temperature and pressure. The inactive compound 60 can be at least one selected from the group consisting of fluorinated compounds, silicon compounds, and phosphoric acid compounds.

[0058] The fluorinated compound as an example of the inactive compound 60 is preferably a fluorinated carbon compound which is a polymer having a CF bond. The number of carbon atoms in the fluorinated carbon compound is 1.9 times or less of the number of fluorine atoms in the fluorinated carbon compound. Examples of the fluorinated carbon compound are perfluoropolyether (PFPE) and hydrofluoroether (HFE).

[0059] The gas layer 70 is formed in the housing space 80 formed by the mounting substrate 10 and the light-transmitting member 40. As described above, the light-emitting element 20 and the inactive compound 60 are arranged in the housing space 80. Therefore, the gas layer 70 is arranged in at least a part of the region of the housing space 80 except the region where the light-emitting element 20 and the inactive compound 60 are arranged.

[0060] Specifically, the gas layer 70 is formed in the second secondary opposing region 83 in the housing space 80. In other words, the gas layer 70 is formed in the second secondary opposing region 83 where the second side wall surface 43b of the second recess 43 faces a portion of the element side surface 24 of the light emitting element 20 located near the mounting substrate 10. In other words, the gas layer 70 contacts a portion of the element side surface 24 of the light emitting element 20 located near the mounting substrate 10. Furthermore, the gas layer 70 contacts a portion of the inactive compound 60.

[0061] The gas layer 70 is formed of at least one selected from the group consisting of air, nitrogen, carbon dioxide, etc. The refractive index of the gas layer 70 is smaller than the refractive index of the inert compound 60. In the first embodiment, the gas layer 70 is formed of air, and the refractive index of air is 1.0.

[0062] 2. Structure of the Light Emitting Element 20

[0063] Reference Figure 2 The structure of the light emitting element 20 will be described. Figure 2 1 is a diagram showing the structure of the light emitting element 20, and is a cross-sectional view in a direction perpendicular to the main surface of the substrate. The light emitting element 20 of this embodiment is a flip-chip type that extracts light from the back side of the substrate (the side opposite to the main surface of the substrate). Therefore, Figure 2 The light emitting element 20 shown is used to make Figure 1 The light emitting element 20 is shown turned upside down.

[0064] The light emitting element 20 mainly includes an element substrate 91, a semiconductor layer 92, an n-side electrode 93, a p-side electrode 94, a protective layer 95, and an anti-reflection layer 96. The light emitting element 20 is a flip-chip type, and therefore has a surface ( Figure 2 The light emitting element 20 is a light emitting element that emits ultraviolet light with a wavelength of 100 nm to 400 nm, and in particular, a light emitting element that emits deep ultraviolet light with a wavelength of 100 nm to 280 nm (UVC band).

[0065] The element substrate 91 is, for example, a substrate formed of sapphire. The element substrate 91 may be any material other than sapphire as long as it has a high transmittance relative to the emission wavelength and can grow a III-nitride semiconductor crystal. For example, the element substrate 91 may be an AlN substrate or an AlN template substrate having an AlN layer formed on a sapphire substrate. When the element substrate 91 is sapphire, the refractive index of the element substrate 91 is 1.76. The thickness of the element substrate 91 is 1 μm or more, preferably 100 μm or more.

[0066] The semiconductor layer 92 is formed on the main surface of the element substrate 91 by crystal growth. The semiconductor layer 92 is composed of a group III nitride semiconductor. The semiconductor layer 92 has at least an n-type layer 92a, an active layer 92b, and a p-type layer 92c. The semiconductor layer 92 is composed of an n-type layer 92a, an active layer 92b, and a p-type layer 92c stacked in order from the element substrate 91 side.

[0067] The n-type layer 92a is composed of a group III nitride semiconductor. The n-type layer 92a is formed, for example, of n-AlGaN. The active layer 92b is composed of a group III nitride semiconductor. The active layer 92b is an SQW structure in which a barrier layer, a well layer, and a barrier layer are stacked in sequence from the n-type layer 92a side. The active layer 92b can also be an MQW structure. The well layer contains AlGaN, and its Al composition is set according to the desired emission wavelength. The barrier layer contains AlGaN with a larger Al composition than the well layer, and the Al composition is, for example, 50% to 100%. The p-type layer 92c constitutes a layer in contact with the electrode, and is therefore called a p-type contact layer. The p-type layer 92c is composed of a group III nitride semiconductor. The p-type layer 92c can also contain p-GaN doped with Mg, or it can contain p-AlGaN.

[0068] The n-side electrode 93 is provided on the n-type layer 92a so as to be in contact with the n-type layer 92a. The n-side electrode pad 21 constituting the n-side electrode 93 is exposed. Figure 1 As shown, the n-side electrode pad 21 is disposed in contact with the first pattern portion 12a of the circuit pattern 12 of the mounting substrate 10. The p-side electrode 94 is disposed on the p-type layer 92c in contact therewith. The p-side electrode 94 includes a reflective layer that reflects ultraviolet light of the emission wavelength. In addition, the p-side electrode pad 22 constituting the p-side electrode 94 is exposed. Figure 1 As shown, the p-side electrode pad 22 is provided in contact with the first pattern portion 12 a of the circuit pattern 12 of the mounting substrate 10 .

[0069] The protective layer 95 is formed of an insulating material and protects the upper surface and side surfaces of the semiconductor layer 92. A portion of the n-side electrode 93 is exposed on the protective layer 95, and the n-side electrode 93 is electrically connected to the n-type layer 92a via the hole in the protective layer 95. A portion of the p-side electrode 94 is exposed on the protective layer 95, and the p-side electrode 94 is electrically connected to the p-type layer 92c via the hole in the protective layer 95.

[0070] The anti-reflection layer 96 is provided on the back side of the element substrate 91 ( Figure 2 The surface of the antireflection layer 96 constitutes the element main surface 23. However, the antireflection layer 96 may not be provided. In this case, for the light emitting element 20, the back surface of the element substrate 91 is exposed to constitute the element main surface 23.

[0071] 3. Detailed description of areas 81 to 83

[0072] Reference Figure 3 The details of the main opposing region 81, the first sub-opposing region 82, and the second sub-opposing region 83 are described. The main opposing region 81 is a region where the first top surface 42a of the first recess 42 faces the element main surface 23 of the light emitting element 20. The facing distance H1 of the main opposing region 81 is 0.1 μm to 500 μm, preferably 0.1 μm to 100 μm.

[0073] The first secondary opposing region 82 is formed by the first side wall surface 42b of the first recess 42 and a portion of the element side surface 24 of the light emitting element 20 located near the element main surface 23 ( Figure 3 The first secondary opposing region 82 has a facing distance H2 that is longer than the facing distance H1 of the main opposing region 81. The facing distance H2 of the first secondary opposing region 82 is 0.1 μm to 500 μm, preferably 0.1 μm to 100 μm. In this embodiment, the first secondary opposing region 82 faces the side of the active layer 92b of the light-emitting element 20. However, the side of the active layer 92b of the light-emitting element 20 is covered by an insulating layer and is therefore not exposed. Therefore, the side of the active layer 92b of the light-emitting element 20 faces the first secondary opposing region 82 via the insulating layer.

[0074] The second secondary opposing region 83 is formed by the second side wall surface 43b of the second recess 43 and the portion of the element side surface 24 of the light emitting element 20 located near the mounting substrate 10 ( Figure 3 The minimum facing distance H3 of the second secondary facing region 83 is longer than the facing distance H2 of the first secondary facing region 82. For example, the minimum facing distance H3 of the second secondary facing region 83 is more than twice the facing distance H2 of the first secondary facing region 82. The facing distance H3 of the second secondary facing region 83 is 0.1 μm to 1000 μm, preferably 50 μm to 500 μm.

[0075] Moreover, if Figure 3 As shown, a length L1 of the first sub-opposing region 82 in the direction Y perpendicular to the mounting surface 10 a of the mounting substrate 10 is longer than a length L2 of the second sub-opposing region 83 in the direction Y perpendicular to the mounting surface 10 a of the mounting substrate 10 .

[0076] 4. Details of Inactive Compound 60

[0077] The inactive compound 60 includes at least one selected from the group consisting of, for example, fluorinated compounds, silicon compounds, and phosphate compounds. The viscosity of the inactive compound 60 is 0.01 to 50 Pa·s, preferably 0.1 to 50 Pa·s. In addition, the contact angle of the inactive compound 60 is 0.1 to 150°, preferably 10 to 50°. Based on these, the inactive compound 60 is retained in the main opposing region 81 and the first secondary opposing region 82 by capillary action.

[0078] In particular, the arithmetic mean roughness Ra of the element side surface 24 of the light-emitting element 20 is 0.1 nm to 100,000 nm. Due to this, the inactive compound 60 is retained in the first secondary opposing region 82 by the capillary phenomenon. In addition, the light-emitting element 20 is formed in a shape without a gap such as a defect or a depression at the boundary between the element main surface 23 and the element side surface 24 throughout the entire periphery of the element main surface 23. Therefore, the inactive compound 60 is retained in the main opposing region 81 and the first secondary opposing region 82.

[0079] In addition, the boiling point of the inactive compound 60 is 100° C. or higher, preferably 260° C. or higher. The junction temperature Tj of the light emitting element 20 is set to be 150° C. or lower. Therefore, even if the temperature of the light emitting element 20 rises, the inactive compound 60 can be prevented from being vaporized, and can be maintained in the main opposing region 81 and the first sub-opposing region 82 by capillary action.

[0080] The inactive compound 60 has a transmittance of 50% or more, preferably 80% or more, for ultraviolet light with a wavelength of 280 nm. The refractive index of the inactive compound 60 is closer to that of the light-transmitting member 40 than that of air. The refractive index of the inactive compound 60 is closer to that of the element substrate 91 ( Figure 2 In this embodiment, the refractive index of the inactive compound 60 may be greater than the refractive index of air and may be the same as or lower than the refractive index of the light-transmitting member 40 and the refractive index of the element substrate 91. When the inactive compound 60 is a fluorinated carbon compound, the refractive index of the fluorinated carbon compound is, for example, not less than 1.2 and not more than 1.6.

[0081] 5. Boundary shape between the inactive compound 60 and the gas layer 70

[0082] Reference Figure 3 The shape of the boundary between the inactive compound 60 and the gas layer 70 will be described. In this embodiment, the inactive compound 60 is filled in the main opposing region 81 and the first sub-opposing region 82. In addition, a portion of the inactive compound 60 slightly enters the second sub-opposing region 83 from the opening of the first sub-opposing region 82. Therefore, the boundary between the inactive compound 60 and the gas layer 70 is located in the second sub-opposing region 83.

[0083] The shape of this boundary depends on the viscosity and contact angle of the inactive compound 60. In the present embodiment, the inactive compound 60 has an angle α with respect to the element side surface 24 of the light emitting element 20 at this boundary.

[0084] The boundary functions as a reflector due to the difference in refractive index between the inactive compound 60 and the gas layer 70. In other words, a reflector having an angle α is formed on the element side surface 24 of the light emitting element 20. The reflectivity of the boundary with respect to ultraviolet light of the emission wavelength is, for example, 50% to 100%.

[0085] Here, the minimum facing distance H3 of the second sub-facing region 83 is more than twice the facing distance H2 of the first sub-facing region 82. In this way, the boundary between the inactive compound 60 and the gas layer 70 is located at a position sufficiently away from the light-transmitting member bonding layer 50. Therefore, the inactive compound 60 is suppressed from flowing to the position of the light-transmitting member bonding layer 50.

[0086] 6. The path of ultraviolet light

[0087] Reference Figure 3 The path of the ultraviolet light emitted by the light emitting element 20 is described. The ultraviolet light emitted by the active layer 92b of the light emitting element 20 is output from the element main surface 23 of the light emitting element 20. The main facing region 81 is filled with an inactive compound 60. Therefore, in the vertical direction of the element main surface 23, the light-transmitting member 40 is arranged via the inactive compound 60. The emitted ultraviolet light enters the light-transmitting member 40 from the element main surface 23 via the inactive compound 60, and is output from the light-transmitting member 40 to the outside.

[0088] Here, the inactive compound 60 contacts the device main surface 23 and contacts the first top surface 42a of the first recess 42 of the light transmitting member 40. Therefore, the emitted ultraviolet light is prevented from being reflected at the device main surface 23 and is output from the light transmitting member 40.

[0089] The ultraviolet light emitted by the active layer 92b of the light emitting element 20 is also output from the element side surface 24 of the light emitting element 20. The first secondary opposing region 82 is filled with an inactive compound 60. The emitted ultraviolet light is output from the light-transmitting member 40 through the inactive compound 60 in the first secondary opposing region 82 from a portion of the element side surface 24 located near the element main surface 23.

[0090] Here, the inactive compound 60 contacts a portion of the element side surface 24 near the element main surface 23, and the inactive compound 60 contacts the first side wall surface 42b of the first recess 42 of the light-transmitting member 40. Therefore, the emitted ultraviolet light is suppressed from being reflected at the element side surface 24 and is output from the light-transmitting member 40.

[0091] Furthermore, part of the ultraviolet light emitted from the element side surface 24 is emitted toward the boundary between the inactive compound 60 and the gas layer 70. In this embodiment, part of the ultraviolet light emitted from the active layer 92b toward the mounting substrate 10 is emitted toward the boundary between the inactive compound 60 and the gas layer 70.

[0092] Regarding the ultraviolet light, the ultraviolet light of the emission wavelength is reflected at the boundary between the inactive compound 60 and the gas layer 70. Therefore, part of the ultraviolet light output from the element side surface 24 is reflected at the boundary and travels toward the light-transmitting member 40. Then, it is output from the light-transmitting member 40 to the outside.

[0093] In addition, a portion of the ultraviolet light emitted by the active layer 92b passes through the boundary between the inactive compound 60 and the gas layer 70. However, very little ultraviolet light passes through the inactive compound 60 to the gas layer 70. Also, a portion of the ultraviolet light emitted by the active layer 92b is output to the gas layer 70 from the portion of the element side 24 that contacts the gas layer 70. However, very little ultraviolet light is output to the gas layer 70. In this way, very little ultraviolet light is output to the gas layer 70. Therefore, even if the light-transmitting component bonding layer 50 uses a material that is not very durable with respect to ultraviolet light, such as silicone resin, the impact is very small. Therefore, the above-mentioned inexpensive material can be applied to the light-transmitting component bonding layer 50.

[0094] 7. Method for manufacturing light emitting device 1

[0095] Reference Figure 4 and Figure 5 A method for manufacturing the light emitting device 1 is described below. Figure 4 In step S1 shown, the light emitting element 20 is bonded to the mounting surface 10a of the mounting substrate 10. Next, in step S2, the light transmissive member bonding layer 50 is disposed on the mounting surface 10a of the mounting substrate 10 or the bonding surface of the flange portion 44 of the light transmissive member 40.

[0096] Next, in step S3, the inactive compound 60 is dropped onto the element main surface 23 of the light emitting element 20. Figure 5 As shown, the inactive compound 60 is retained on the element main surface 23 of the light emitting element 20 by surface tension. The volume of the dropped inactive compound 60 is about the same as the total volume of the main opposing region 81 and the first sub-opposing region 82. In detail, the volume of the dropped inactive compound 60 is slightly larger than the total volume of the main opposing region 81 and the first sub-opposing region 82. Moreover, the volume of the dropped inactive compound 60 is sufficiently smaller than the total volume of the main opposing region 81, the first sub-opposing region 82, and the second sub-opposing region 83.

[0097] Then, in Figure 4 In step S4 shown in FIG. Figure 5 As shown by the arrow P in the middle, the light-transmitting member 40 is covered and bonded to the mounting substrate 10. At this time, as the element main surface 23 and the first top surface 42a of the first recess 42 of the light-transmitting member 40 approach each other, the inactive compound 60 dripped onto the element main surface 23 gradually moves toward the element side surface 24 after contacting the first top surface 42a. The inactive compound 60 that has moved to the element side surface 24 is held in the first secondary facing region 82 by the capillary phenomenon between the element side surface 24 and the first side wall surface 42b of the first recess 42 of the light-transmitting member 40. In this way, Figure 1 The light emitting device 1 shown is completed.

[0098] 8. Effects

[0099] Next, the effects of the light emitting device of the first embodiment will be described in detail. According to the light emitting device of the first embodiment, the inactive compound 60 which is liquid at normal temperature and pressure is filled in the main facing region 81 where the element main surface 23 and the first top surface 42a of the recess 41 of the light transmissive member 40 face each other, and is filled in the first secondary facing region 82 where the portion of the element side surface 24 located near the element main surface 23 and the first side wall surface 42b of the recess 41 of the light transmissive member 40 face each other. In addition, the gas layer 70 is formed in the second secondary facing region 83 facing the portion of the element side surface 24 located near the mounting substrate 10. According to the above, the inactive compound filled in the first secondary facing region 82 is suppressed from flowing out and reaching the light transmissive member bonding layer 50 bonding the light transmissive member 40 to the mounting substrate 10, thereby preventing the bonding between the light transmissive member 40 and the mounting substrate 10 from being hindered by the inactive compound 60. Furthermore, the ultraviolet light radiated from the portion of the element side surface 24 located near the element main surface 23 enters the light-transmitting member 40 via the inactive compound 60 filled in the first secondary opposing region 82, thereby suppressing the ultraviolet light from reaching the light-transmitting member bonding layer 50. Therefore, the degradation of the light-transmitting member bonding layer 50 caused by the ultraviolet light is suppressed, and the reliability of the light-transmitting member bonding layer 50 is improved.

[0100] Furthermore, in the direction perpendicular to the mounting surface 10a, the light-transmitting member bonding layer 50 bonding the light-transmitting member 40 to the mounting substrate 10 is located closer to the mounting substrate 10 than the first secondary opposing region 82, so that the ultraviolet light radiated from at least the portion near the element main surface 23 in the element side surface 24 is not easy to reach the light-transmitting member bonding layer 50. Therefore, the degradation of the light-transmitting member bonding layer 50 due to ultraviolet light is suppressed, and the reliability of the light-transmitting member bonding layer 50 is improved.

[0101] Furthermore, in the present first embodiment, the light-transmitting member bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the active layer 92b of the light-emitting element 20 in the direction Y perpendicular to the mounting surface 10a. Thus, the ultraviolet light radiated from the active layer 92b of the light-emitting element 20 enters the light-transmitting member 40 via the inactive compound 60, and the ultraviolet light is suppressed from reaching the light-transmitting member bonding layer 50, thereby further suppressing the degradation of the light-transmitting member bonding layer 50 caused by the ultraviolet light, and further achieving the improvement of the reliability of the light-transmitting member bonding layer 50.

[0102] Furthermore, in the first embodiment, the side surface of the active layer 92b of the light emitting element 20 faces the first sub-opposing region 82 and faces the inactive compound 60. Thus, the ultraviolet light radiated from the active layer 92b of the light emitting element 20 is incident on the light-transmitting member 40 via the inactive compound 60, and the ultraviolet light is suppressed from reaching the light-transmitting member bonding layer 50, thereby further suppressing the degradation of the light-transmitting member bonding layer 50 caused by the ultraviolet light, and further achieving the improvement of the reliability of the light-transmitting member bonding layer 50.

[0103] Furthermore, in the first embodiment, the minimum facing distance H3 of the second sub-opposing region 83 is more than twice the facing distance H2 of the first sub-opposing region 82. As a result, the distance between the inactive compound 60 filled in the first sub-opposing region 82 and the light-transmitting member bonding layer 50 becomes longer, so that even if the inactive compound 60 flows out, it can be prevented from reaching the light-transmitting member bonding layer 50, thereby further improving the reliability of the light-transmitting member bonding layer 50.

[0104] In the first embodiment, the recess 41 includes: a first recess 42 including a first top surface 42a and a first side wall surface 42b; and a second recess 43 located on the opening side of the first recess 42 and including a second top surface 43a adjacent to the first side wall surface 42b and a second side wall surface 43b adjacent to the second top surface 43a; the first secondary facing region 82 is a region where a portion of the element side surface 24 of the light emitting element 20 located near the element main surface 23 faces the first side wall surface 42b of the recess 41; and the second secondary facing region 83 is a region where a portion of the element side surface 24 of the light emitting element 20 located near the mounting substrate 10 faces the second side wall surface 43b of the recess 41. Thus, a step is formed at the boundary between the first recess 42 and the second recess 43, so that the inactive compound 60 filled in the first secondary facing region 82 can be suppressed from reaching the light-transmitting member bonding layer 50, and the reliability of the light-transmitting member bonding layer 50 can be further improved.

[0105] In the first embodiment, the light-transmitting member bonding layer 50 includes a silicone resin. Thus, the light-transmitting member bonding layer 50 has high adhesion to both the light-transmitting member 50 and the mounting substrate 10 , thereby further improving the reliability of the light-transmitting member bonding layer.

[0106] As described above, according to the first embodiment, it is possible to provide the light emitting device 1 that achieves improved reliability of the light transmissive member bonding layer 50 that is the bonding portion between the light transmissive member 40 and the mounting substrate 10 .

[0107] (Implementation Method 2)

[0108] In this embodiment 1, if Figure 3As shown in FIG. 1 , the first sub-opposing region 82 faces the side of the active layer 92b of the light emitting element 20, but it may also be replaced by Figure 6 As in the second embodiment shown, the first sub-opposing region 82 has no side facing the active layer 92b of the light-emitting element 20, and the second sub-opposing region 83 faces the side of the active layer 92b of the light-emitting element 20 and faces the gas layer 70. In addition, in this second embodiment, the same reference numerals are given to the same structures as those in the first embodiment, and their descriptions are omitted.

[0109] In the second embodiment, a part of the ultraviolet light emitted from the active layer 92b of the light emitting element 20 is incident on the inactive compound 60 of the first sub-opposing region 82 from the element side surface 24 of the light emitting element 20 facing the first sub-opposing region 82. Then, it is reflected toward the light-transmitting member 40 by the boundary between the inactive compound 60 and the gas layer 70, is incident on the light-transmitting member 40, and is output to the outside.

[0110] According to the second embodiment, the distance between the inactive compound 60 filled in the first sub-opposing region 82 and the light-transmitting component bonding layer 50 is lengthened. Therefore, even if the inactive compound 60 flows out, it can be prevented from reaching the light-transmitting component bonding layer 50, thereby further improving the reliability of the light-transmitting component bonding layer 50.

[0111] In addition, in the second embodiment, according to the situation of the first embodiment, there is a tendency to increase the ultraviolet light emitted directly from the side of the active layer 92b to the gas layer 70 in the second sub-opposing region 83, and although the degree of improvement in the ultraviolet light extraction efficiency of the light-emitting device 1 as a whole is reduced compared with the situation of the first embodiment, it is needless to say that the ultraviolet light extraction efficiency is improved compared with the case where the inactive compound 60 of the first sub-opposing region 82 is not present. In the second embodiment, the same effects as the situation of the first embodiment are achieved except that the degree of improvement in the ultraviolet light extraction efficiency is reduced.

[0112] (Implementation 3)

[0113] In the above embodiment 1, if Figure 1 As shown in the figure, the outer periphery 10b of the mounting substrate 10 as the joint portion with the flange portion 44 of the light-transmitting member 40 is located on the same plane relative to the mounting surface 10a, but it is not limited to this, and it may also be as shown in FIG. Figure 7 In the third embodiment shown, the mounting surface 10a is provided at the bottom of the substrate recess 13 formed in the mounting substrate 10, and the outer peripheral edge 10b is located outside the substrate recess 13 and is not located on the same plane as the mounting surface 10a.

[0114] In the third embodiment, the side wall surface 13b of the substrate recess 13 faces the element side surface 24, and the area between the side wall surface 13b and the element side surface 24 forms the second secondary facing area 83. The second top surface 13a, which is the upper surface of the second secondary facing area 83, is formed in a flat surface parallel to the mounting surface 10a of the mounting substrate 10. In addition, the gas layer 70 is formed in the second secondary facing area 83.

[0115] In Embodiment 3, the bonding position where the light-transmitting member 40 is bonded to the mounting substrate 10 is also located closer to the mounting surface 10a of the mounting substrate 10 than the position of the active layer 92b of the light-emitting element 20 ( Figure 1 ). In other words, the light-transmitting component bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the first sub-opposing region 82. Moreover, the light-transmitting component bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the active layer 92b. In addition, in this embodiment 3, the same figure marks are marked for the structures equivalent to the above-mentioned embodiment 1 and their descriptions are omitted. Moreover, in embodiment 3, the same effects as those of embodiment 1 are also achieved.

[0116] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments within the scope not departing from the gist of the invention.

Claims

1. A light emitting device, which is a light emitting device that emits ultraviolet light, characterized in that: have: A mounting substrate having a mounting surface; an ultraviolet luminescent light emitting element, which is arranged on the mounting surface of the mounting substrate and has an element main surface facing the side opposite to the mounting surface and an element side surface adjacent to the element side surface; a light-transmitting member disposed on the mounting surface of the mounting substrate, forming a housing space in a region facing the mounting surface of the mounting substrate, and having a recess constituting at least a portion of the housing space and capable of housing at least a portion of the light-emitting element; An inactive compound, which is disposed in the containing space and is liquid at normal temperature and pressure; a gas layer formed in the receiving space; as well as a light-transmitting member bonding layer, which is disposed between the mounting substrate and the light-transmitting member and bonds the mounting substrate and the light-transmitting member, The inactive compound is filled in a main facing region where the main surface of the light-emitting element faces the first top surface of the recess and a first secondary facing region where a portion of the side surface of the light-emitting element located near the main surface faces the first side wall of the recess. The gas layer is formed in a second sub-opposing region of the side surface of the element facing the light emitting element, which is located near the mounting substrate. The light-transmitting member bonding layer is located closer to the mounting substrate than the first sub-opposing region in a direction perpendicular to the mounting surface.

2. The light emitting device according to claim 1, characterized in that: The light-transmitting member bonding layer is located closer to the mounting surface of the mounting substrate than the active layer of the light-emitting element in a direction perpendicular to the mounting surface.

3. The light emitting device according to claim 2, characterized in that: A side surface of the active layer of the light emitting element faces the first sub-opposing region and faces the inactive compound.

4. The light emitting device according to claim 2, characterized in that: A side surface of the active layer of the light emitting element faces the second sub-opposing region and faces the gas layer.

5. The light emitting device according to any one of claims 1 to 4, characterized in that: The minimum facing distance of the second secondary facing regions is at least twice the facing distance of the first secondary facing regions.

6. The light emitting device according to any one of claims 1 to 4, characterized in that: The recess has: A first recess having the first top surface and the first side wall surface; as well as a second recess, which is located at the opening side of the first recess and has a second top surface adjacent to the first side wall surface and a second side wall surface adjacent to the second top surface, The first secondary opposing region is a region where a portion of the element side surface of the light emitting element near the element main surface faces the first side wall surface of the recess. The second sub-opposing region is a region where a portion of the element side surface of the light emitting element near the mounting substrate faces the second side wall surface of the recess.

7. The light emitting device according to any one of claims 1 to 4, characterized in that: The light-transmitting member bonding layer includes a silicone resin.

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