Light-emitting device

Abstract

To provide a light-emitting device that can be configured to: hold an inert compound that is liquid at room temperature and normal pressure in the main opposing region between the main surface of a light-emitting element and a light-transmitting member; and to form a gas layer in a region facing the side surface of the element.SOLUTION: A light-emitting device 1 includes: a mounting substrate 10; an ultraviolet-emitting light-emitting element 20 having an element main surface 23 facing a side opposite a mounting surface 10a, and an element side surface 24; a light-transmitting member 40 forming an accommodation space 80 for accommodating the light-emitting element 20 in a region facing the mounting surface 10a of the mounting substrate 10; an inert compound 60 that is liquid at room temperature and normal pressure and that is filled in at least a main opposing region 81 between the element main surface 23 of the light-emitting element 20 and the light-transmitting member 40 in the accommodation space 80; and a gas layer 70 formed in a region facing the element side surface 24 in the accommodation space 80. Therein a contact angle θ1 of the inert compound 60 with respect to the element main surface 23 at a temperature of 25°C is 10° to 30°.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Light-emitting devices using ultraviolet light-emitting elements are used for various purposes. For example, Patent Documents 1 and 2 disclose such light-emitting devices in which an ultraviolet light-emitting element is mounted on a mounting board and the ultraviolet light emission side of the light-emitting element is covered with a sealing material that transmits ultraviolet light by a dome-shaped light-transmitting member.

[0003] In one configuration disclosed in Patent Document 1, the space between the entire main surface and side surfaces of the light-emitting element opposite the mounting substrate and the inner surface of the light-transmitting member is filled with a cured sealing material that transmits ultraviolet light. In another configuration disclosed in Patent Document 1, the space between the entire main surface and side surfaces of the light-emitting element opposite the mounting substrate and the inner surface of the light-transmitting member is filled with a liquid sealing material that transmits ultraviolet light.

[0004] In the configuration disclosed in Patent Document 2, a fluorocarbon compound that is liquid at room temperature and normal pressure is filled between the upper surface, which is the main surface of the light-emitting element, and the inner surface of the light-transmitting member facing it, and an air layer exists between the entire side surface of the light-emitting element and the inner surface of the light-transmitting member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-127156 A [Patent Document 2] JP 2022-108692 A Summary of the Invention [Problem to be solved by the invention]

[0006] In one configuration disclosed in Patent Document 1, when a hardened sealing material is used, stress may be generated in the light emitting element as the sealing material hardens. In another configuration disclosed in Patent Document 1, when a liquid sealing material is used, the liquid sealing material may come into contact with the bonding material between the mounting substrate and the light-transmitting member, thereby affecting the bonding strength of the bonding material.

[0007] Therefore, as in the configuration disclosed in Patent Document 2, it is desirable to arrange an inactive compound that is liquid at room temperature and normal pressure in the main opposing region between the element main surface of the light-emitting element and the light-transmitting member, and to form a gas layer in the region facing the element side surface. In this configuration, the liquid inactive compound and the gas layer are present in the space formed by the mounting substrate, the light-emitting element, and the light-transmitting member, so it is necessary to devise a way to maintain the position of the liquid inactive compound. Therefore, it is particularly necessary to devise an inactive compound that is liquid at room temperature and normal pressure.

[0008] The present invention has been made in consideration of the above background, and aims to provide a light-emitting device that can be configured to hold a liquid inactive compound at room temperature and normal pressure in the main opposing region between the main surface of the light-emitting element and a translucent member, and to form a gas layer in the region facing the side surface of the element. [Means for solving the problem]

[0009] One aspect of the present invention is a mounting substrate having a mounting surface; an ultraviolet light-emitting element disposed on the mounting surface of the mounting substrate, the light-emitting element having a main surface facing the opposite side to the mounting surface and a side surface adjacent to the main surface; a light-transmitting member that is disposed on the mounting surface of the mounting substrate and that forms an accommodation space for accommodating the light-emitting element in an area facing the mounting surface of the mounting substrate; an inactive compound that is liquid at room temperature and normal pressure and that is filled in at least a main opposing region between the main surface of the light-emitting element and the light-transmitting member in the accommodation space; a gas layer formed in a region facing the element side surface in the accommodation space, The light emitting device has a contact angle of the inactive compound with respect to the main surface of the element at a temperature of 25° C. of 10° to 30°. Effect of the Invention

[0010] According to the above embodiment, the contact angle of the inactive compound with respect to the main surface of the light-emitting element at a temperature of 25°C is 10° to 30°, so that the inactive compound can be held in a liquid state at room temperature and normal pressure in the main opposing region between the main surface of the light-emitting element and the light-transmitting member, and a gas layer can be formed in the region facing the side surface of the element. [Brief description of the drawings]

[0011] [Figure 1] 3 is a cross-sectional view of the light emitting device taken along a plane perpendicular to the mounting substrate in the first embodiment. [Diagram 2] FIG. 2 is a conceptual cross-sectional view illustrating the configuration of the light-emitting element in the first embodiment. [Diagram 3] 2 is an enlarged cross-sectional view of the vicinity of a second minor opposing region in FIG. 1; [Figure 4] FIG. 3 is a flow diagram illustrating a method for manufacturing the light emitting device according to the first embodiment. [Diagram 5] 3A to 3C are conceptual diagrams illustrating a method for manufacturing the light emitting device according to the first embodiment. [Figure 6] FIG. 11 is an enlarged cross-sectional view of the vicinity of a second minor opposing region in the second embodiment. [Figure 7] FIG. 11 is a cross-sectional view of the light emitting device in a plane perpendicular to the mounting substrate in the third embodiment. [Figure 8] FIG. 11 is a cross-sectional view of the light emitting device in a plane perpendicular to the mounting substrate in the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The light emitting device includes a mounting substrate having a mounting surface, an ultraviolet light emitting element disposed on the mounting surface of the mounting substrate and having an element main surface facing the opposite side to the mounting surface and an element side surface adjacent to the element main surface, a light transmitting member disposed on the mounting surface of the mounting substrate and forming an accommodation space for accommodating the light emitting element in an area facing the mounting surface of the mounting substrate, an inactive compound that is liquid at room temperature and normal pressure and that is filled in at least the main opposing area between the element main surface of the light emitting element and the light transmitting member in the accommodation space, and a gas layer formed in an area facing the element side surface in the accommodation space. The contact angle of the inactive compound with respect to the element main surface at a temperature of 25°C is 10° to 30°.

[0013] In the light emitting device, the inactive compound may have a viscosity of 0.01 to 50 Ps·s at a temperature of 25° C. This allows the contact angle of the inactive compound with respect to the main surface of the element at a temperature of 25° C. to be within the above range.

[0014] The principal surface of the element may have an arithmetic mean roughness Ra of 0.1 to 100,000 nm, which allows the contact angle of the inactive compound with respect to the principal surface of the element at a temperature of 25° C. to be within the above range.

[0015] The inactive compound is preferably disposed in the accommodation space in contact with at least a portion of the element side surface of the light-emitting element, and the contact angle of the inactive compound with the element side surface at a temperature of 25° C. is 10° to 30°. This allows a configuration in which the inactive compound is held in contact with at least a portion of the element side surface of the light-emitting element, and a gas layer is formed in the region facing the element side surface.

[0016] The arithmetic mean roughness Ra of the element side surface may be 0.1 to 100,000 nm. The contact angle of the inactive compound with respect to the element side surface at a temperature of 25° C. may be within the above range.

[0017] The boiling point of the inactive compound is preferably 150° C. or higher. This makes it possible to hold the inactive compound at a desired position even when the temperature of the light-emitting element rises during operation.

[0018] Also, it is preferable that the junction temperature of the light emitting element during operation is set to 150° C. or less, whereby the inactive compound can be held at a desired position.

[0019] The inactive compound may have a transmittance of 50% or more for ultraviolet light of an emission wavelength, which can increase the light extraction efficiency of ultraviolet light when the inactive compound is disposed.

[0020] In addition, the inactive compound may be a fluoride compound, which can reduce the refractive index difference between the light-emitting element and the inactive compound, and between the light-transmitting member and the inactive compound, thereby increasing the light extraction efficiency of ultraviolet light.

[0021] The light-emitting element may be a flip-chip type that extracts light from a back side of an element substrate included in the light-emitting element, and the element main surface may be located on the back side of a surface of the element substrate on which a semiconductor layer is formed, thereby making it possible to hold a liquid inactive compound at room temperature and normal pressure in a main opposing region between the element main surface of the light-emitting element and the light-transmitting member.

[0022] The opposing distance of the main opposing regions is preferably 0.1 to 500 μm, whereby an inactive compound that is liquid at room temperature and normal pressure can be held in the main opposing region between the main element surface of the light-emitting element and the light-transmitting member.

[0023] (Embodiment 1) 1. Configuration of the Light Emitting Device 1 The configuration of the light emitting device 1 of this embodiment will be described with reference to Fig. 1. The light emitting device 1 constitutes a light emitting device package that houses an ultraviolet light emitting element 20 as a main component. The ultraviolet light emitting device 1 includes a mounting substrate 10, the 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.

[0024] The mounting substrate 10 has a mounting surface 10a, and is a substrate 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 case shape having a recess.

[0025] The mounting substrate 10 has a main body 11 and a circuit pattern 12. The main body 11 of the mounting substrate 10 is formed, for example, in a flat plate shape. The main body 11 is formed to include at least one type of ceramic selected from the group including AlN, Al2O3, SiC, and Si2N4. The circuit pattern 12 has a first pattern portion 12a exposed on one side of the main body 11 of the mounting substrate 10, a second pattern portion 12b exposed on the other side (the lower surface in FIG. 1) of the main body 11 of the mounting substrate 10, and a connection pattern portion (not shown) that connects the first pattern portion 12a and the second pattern portion 12b. The surface of the mounting substrate 10 facing the first pattern portion 12a constitutes the mounting surface 10a. The surface of the mounting substrate 10 facing the second pattern portion 12b constitutes the surface exposed to the outside. The second pattern portion 12b constitutes a portion electrically connected to an external mounting substrate (not shown).

[0026] The light emitting element 20 is composed of a group III nitride and emits ultraviolet light with a predetermined emission wavelength. The light emitting element 20 is an ultraviolet light emitting element with an emission wavelength of 100 nm to 400 nm. In particular, the light emitting element 20 is a deep ultraviolet light emitting element with an emission wavelength of 100 nm to 280 nm (UVC band). The thickness of the light emitting element 20 (thickness in the vertical direction in FIG. 1) is 1 μm or more. More specifically, the thickness of the light emitting element 20 is 400 μm or more and 1000 μm or less.

[0027] 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 type element having electrode pads 21, 22 on the surface facing the mounting substrate 10. Therefore, the electrode pads 21, 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. The junction temperature Tj of the light emitting element 20 during operation is configured to be 150° C. or less, preferably 100° C. or less.

[0028] In this embodiment, the light emitting element 20 has an element main surface 23 facing the side opposite to the mounting surface 10a of the mounting substrate 10 (the upper side in FIG. 1), and an element side surface 24 located in the circumferential direction and adjacent to the element main surface 23. The element main surface 23 is formed in a planar shape parallel to the mounting surface 10a of the mounting substrate 10. The element main surface 23 is formed in a rectangular shape. The arithmetic mean roughness Ra of the element main surface 23 is 0.1 to 100,000 nm.

[0029] The element side surfaces 24 are adjacent to each side of the outer periphery of the element principal surface 23. The element side surfaces 24 have surfaces that are approximately perpendicular to the mounting surface 10a of the mounting substrate 10. In other words, the element side surfaces 24 have four surfaces adjacent to each side of the element principal surface 23. The arithmetic mean roughness Ra of the element side surfaces 24 of the light emitting element 20 is 0.1 to 100,000 nm.

[0030] In the light emitting element 20, the angle between the element principal surface 23 and the element side surface 24 is in the range of 80 to 100°, and preferably 90°, over the entire outer periphery of the element principal surface 23. The light emitting element 20 is formed in a shape that has no chipping such as notches or dents at the boundary between the element principal surface 23 and the element side surface 24 over the entire outer periphery of the element principal surface 23.

[0031] 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, 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.

[0032] The light-transmitting member 40 is disposed on the mounting surface 10a side of the mounting substrate 10. In detail, the light-transmitting member 40 is bonded to the outer periphery of the mounting surface 10a of the mounting substrate 10 via a light-transmitting member bonding layer 50. The light-transmitting member 40 is a sealing material that forms an accommodation space 80 in an area facing the mounting surface 10a of the mounting substrate 10. The accommodation space 80 accommodates the light-emitting element 20 and the like.

[0033] The light-transmitting member 40 may be made of any material that transmits ultraviolet light of the emission wavelength, for example, glass. For example, the light-transmitting member 40 is made of at least one material selected from the group consisting of quartz, borosilicate, sapphire, fluoride, silicone resin, metaphosphate, and the like, as examples of glass. When the light-transmitting member 40 is made of quartz, the refractive index of the light-transmitting member 40 is 1.45.

[0034] Here, the joint position between the light-transmitting member 40 and the mounting substrate 10 (i.e., the position of the outer circumferential edge 10b of the mounting substrate 10 to which the flange portion 44 of the light-transmitting member 40 is joined) is located closer to the mounting surface 10a of the mounting substrate 10 than the element main surface 23 of the light-emitting element 20 in the direction perpendicular to the mounting surface 10a of the mounting substrate 10. Furthermore, the joint position between the light-transmitting member 40 and 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 in the direction perpendicular to the mounting surface 10a of the mounting substrate 10.

[0035] In this embodiment, the joint position between the light-transmitting member 40 and the mounting substrate 10 is located along the surface of the mounting surface 10a of the mounting substrate 10, and the active layer 92b is located at a distance from the mounting surface 10a. With this configuration, as described above, the joint position between the light-transmitting member 40 and the mounting substrate 10 is located closer to the mounting surface 10a of the mounting substrate 10 (lower side in FIG. 1) than the position of the active layer 92b of the light-emitting element 20.

[0036] The light-transmitting member 40 has, for example, a convex lens shape. That is, the outer surface of the light-transmitting member 40 is formed into a convex curved shape. By forming the light-transmitting member 40 into a convex lens shape, the ultraviolet light emitted by the light-emitting element 20 can be output mainly in a direction perpendicular to the mounting substrate 10.

[0037] The light-transmitting member 40 has a recess 41 that constitutes at least a part of the accommodation space 80 on a surface facing the mounting surface 10a of the mounting substrate 10. The recess 41 is configured to be able to accommodate at least a part of the light-emitting element 20. In this embodiment, the recess 41 is configured to be able to accommodate the entire light-emitting element 20. In other words, the accommodation space 80 is formed between the recess 41 of the light-transmitting member 40 and the mounting surface 10a of the mounting substrate 10.

[0038] The recess 41 has a first recess 42 and a second recess 43. The recess 41 configures a stepped recess by the first recess 42 and the second recess 43. Note that the recess 41 may configure a stepped recess having three or more steps.

[0039] The first recess 42 is located at 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 be able to accommodate a part 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 approximately one-half to two-thirds the thickness of the light-emitting element 20, and the depth D1 of the first recess 42 shown in FIG. 3 is 10 to 1000 μm. The first recess 42 includes a first ceiling surface 42a and a first side wall surface 42b.

[0040] The first ceiling surface 42a is formed in a planar shape parallel to the mounting surface 10a of the mounting substrate 10. The first ceiling surface 42a is formed in a rectangular shape. The first ceiling surface 42a is disposed so as to face the element main surface 23 of the light emitting element 20. In detail, the first ceiling surface 42a is formed parallel to the element main surface 23 of the light emitting element 20 and disposed at a predetermined distance from the element main surface 23. Therefore, a main facing region 81 is formed in which the first ceiling surface 42a of the first recess 42 and the element main surface 23 of the light emitting element 20 face each other.

[0041] The first side wall surface 42b is adjacent to each side of the outer periphery of the first ceiling surface 42a. The first side wall surface 42b has a surface in a direction substantially perpendicular to the mounting surface 10a of the mounting substrate 10. That is, the first side wall surface 42b has four surfaces adjacent to each side of the first ceiling surface 42a. Each surface of the first side wall surface 42b is formed parallel to a portion of the element side surface 24 of the light emitting element 20 closer to the element main surface 23 (the upper portion in FIG. 1), and is disposed at a predetermined distance from the portion of the element side surface 24 closer to the element main surface 23. Therefore, a first sub-facing region 82 is formed in which the first side wall surface 42b of the first recess 42 and the portion of the element side surface 24 of the light emitting element 20 closer to the element main surface 23 (the upper portion in FIG. 1) face each other.

[0042] The second recess 43 is located on the opening side of the first recess 42, has an opening that is an enlarged version of the opening of the first recess 42, and has a ceiling surface that is shallower than the first recess 42. The second recess 43 is configured to be able to accommodate another part 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 approximately half the thickness of the light-emitting element 20, and the depth D2 of the second recess 43 shown in FIG. 3 is 10 to 1000 μm. The second recess 43 includes a second ceiling surface 43a and a second side wall surface 43b.

[0043] The second ceiling surface 43a is formed in a plane parallel to the mounting surface 10a of the mounting substrate 10. The second ceiling surface 43a is adjacent to the first side wall surface 42b of the first recess 42. The outer peripheral shape of the second ceiling surface 43a may be rectangular or circular. The second ceiling surface 43a is formed in a ring shape. The second ceiling surface 43a is disposed opposite the mounting surface 10a of the mounting substrate 10 and is disposed at a predetermined distance from the mounting surface 10a.

[0044] The second side wall surface 43b is adjacent to the outer periphery of the second ceiling surface 43a. The second side wall surface 43b has an angle with respect to the mounting surface 10a of the mounting substrate 10. For example, the second side wall surface 43b forms an inclined surface having an acute angle with respect to the mounting surface 10a. The second side wall surface 43b faces a portion of the element side surface 24 of the light emitting element 20 closer to the mounting substrate 10 (the lower portion in FIG. 1), and is disposed at a predetermined distance from the portion of the element side surface 24 closer to the mounting substrate 10. Therefore, a second sub-facing region 83 is formed in which the second side wall surface 43b of the second recess 43 faces the portion of the element side surface 24 of the light emitting element 20 closer to the mounting substrate 10 (the lower portion in FIG. 1).

[0045] The light-transmitting member bonding layer 50 is disposed between the outer peripheral edge 10b of the mounting surface 10a of the mounting substrate 10 and the flange portion 44 forming the outer peripheral edge of the light-transmitting member 40, and bonds the mounting surface 10a of the mounting substrate 10 and the light-transmitting member 40. The light-transmitting member bonding layer 50 is formed containing at least one selected from the group including silicone resin, epoxy resin, fluororesin, solder, silane, glass, and brazing material. In the present embodiment 1, the outer peripheral edge 10b is located on the same plane as the mounting surface 10a.

[0046] As described above, the bonding position between the light-transmitting member 40 and the mounting substrate 10 is located closer to the mounting surface 10a of the mounting substrate 10 (lower side in FIG. 1) than the position of the active layer 92b of the light-emitting element 20 in the perpendicular direction Y of the mounting surface 10a of the mounting substrate 10. That is, the light-transmitting member bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the first minor facing region 82. Furthermore, the light-transmitting member bonding layer 50 is located closer to the mounting surface 10a of the mounting substrate 10 than the position of the active layer 92b.

[0047] Therefore, even if a material that is not very durable against ultraviolet light of the emission wavelength is used for the light-transmitting member bonding layer 50, the effect is extremely small. Therefore, the above-mentioned inexpensive materials can be applied to the light-transmitting member bonding layer 50. Of course, the light-transmitting member bonding layer 50 may be made of a material that is highly durable against ultraviolet light, such as a silicone resin.

[0048] The inactive compound 60 is disposed in a storage space 80 formed by the mounting substrate 10 and the light-transmitting member 40. The inactive compound 60 is disposed in a main facing region 81 and a first sub-facing region 82 of the storage space 80. That is, the inactive compound 60 is filled in the main facing region 81 where the first ceiling surface 42a of the first recess 42 and the element main surface 23 of the light-emitting element 20 face each other. Therefore, the inactive compound 60 is in contact with the first ceiling surface 42a of the first recess 42 and also in contact with the element main surface 23 of the light-emitting element 20.

[0049] Furthermore, the inactive compound 60 is filled in a first sub-facing 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 closer to the element main surface 23. Therefore, the inactive compound 60 contacts the first side wall surface 42b of the first recess 42 and also contacts a portion of the element side surface 24 of the light emitting element 20 closer to the element main surface 23. The side surface of the active layer 92b of the light emitting element 20 faces the first sub-facing region 82. In other words, the side surface of the active layer 92b of the light emitting element 20 faces the inactive compound 60.

[0050] The inactive compound 60 is liquid at normal temperature and pressure. The inactive compound 60 may be at least one selected from the group consisting of fluoride compounds, silicon compounds, and phosphate compounds.

[0051] As an example of the fluorinated compound of the inactive compound 60, for example, a fluorocarbon compound that is a polymer having a C—F bond is suitable. The number of carbon atoms in the fluorocarbon compound is 1.9 times or less the number of fluorine atoms in the fluorocarbon compound. Examples of the fluorocarbon compound include perfluoropolyether (PFPE) and hydrofluoroether (HFE).

[0052] The gas layer 70 is formed in the accommodation 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 accommodation space 80. Therefore, the gas layer 70 is arranged in at least a part of the area of ​​the accommodation space 80 excluding the area where the light-emitting element 20 and the inactive compound 60 are arranged.

[0053] In detail, the gas layer 70 is formed in the second sub-facing region 83 of the accommodation space 80. That is, the gas layer 70 is formed in the second sub-facing 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 closer to the mounting substrate 10. That is, the gas layer 70 contacts the portion of the element side surface 24 of the light emitting element 20 closer to the mounting substrate 10. Furthermore, the gas layer 70 contacts a portion of the inactive compound 60.

[0054] The gas layer 70 is formed containing 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 inactive compound 60. In the present embodiment 1, the gas layer 70 is formed of air, and the refractive index of air is 1.0.

[0055] 2. Configuration of the Light Emitting Element 20 The configuration of the light-emitting element 20 will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing the configuration of the light-emitting element 20 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 surface of the substrate (the surface opposite to the main surface of the substrate). Therefore, the light-emitting element 20 shown in Fig. 2 is a view obtained by turning the light-emitting element 20 shown in Fig. 1 upside down.

[0056] 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 antireflection layer 96. The light emitting element 20 is of a flip chip type, and has a structure in which light is extracted from the surface on the element substrate 91 side (the lower surface in FIG. 2). The light emitting element 20 is an ultraviolet light emitting element having an emission wavelength of 100 nm to 400 nm, and in particular, is a deep ultraviolet light emitting element having an emission wavelength of 100 nm to 280 nm (UVC band).

[0057] The element substrate 91 is, for example, a substrate made of sapphire. In addition to sapphire, any material may be used for the element substrate 91 as long as it has a high transmittance for the emission wavelength and can grow a crystal of a III-nitride semiconductor. For example, the element substrate 91 may be an AlN substrate or an AlN template substrate in which an AlN layer is formed on a sapphire substrate. When the element substrate 91 is made of 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.

[0058] The semiconductor layer 92 is formed by crystal growth on the main surface of the element substrate 91. The semiconductor layer 92 is configured to include 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 configured by laminating the n-type layer 92a, the active layer 92b, and the p-type layer 92c in this order from the element substrate 91 side.

[0059] The n-type layer 92a is made of a group III nitride semiconductor. The n-type layer 92a is made of, for example, n-AlGaN. The active layer 92b is made of a group III nitride semiconductor. The active layer 92b has an SQW structure in which a barrier layer, a well layer, and a barrier layer are stacked in this order from the n-type layer 92a side. The active layer 92b may have an MQW structure. The well layer contains AlGaN, and the Al composition is set according to a desired emission wavelength. The barrier layer contains AlGaN having a larger Al composition than the well layer, and the Al composition is, for example, 50 to 100%. The p-type layer 92c is also called a p-type contact layer because it constitutes a layer in contact with an electrode. The p-type layer 92c is made of a group III nitride semiconductor. The p-type layer 92c may contain Mg-doped p-GaN or p-AlGaN.

[0060] The n-side electrode 93 is provided on and in contact with the n-type layer 92a. The n-side electrode pad 21 constituting the n-side electrode 93 is provided in an exposed state. The n-side electrode pad 21 is provided in contact with the first pattern portion 12a of the circuit pattern 12 of the mounting substrate 10, as shown in FIG. 1. The p-side electrode 94 is provided on and in contact with the p-type layer 92c. The p-side electrode 94 includes a reflective layer that reflects ultraviolet light having an emission wavelength. Furthermore, the p-side electrode pad 22 constituting the p-side electrode 94 is provided in an exposed state. The p-side electrode pad 22 is provided in contact with the first pattern portion 12a of the circuit pattern 12 of the mounting substrate 10, as shown in FIG. 1.

[0061] The protective layer 95 is made 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 through a 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 through a hole in the protective layer 95.

[0062] The antireflection layer 96 is provided on the back surface (the lower surface in FIG. 2, the surface on the light extraction side) of the element substrate 91, and the surface of the antireflection layer 96 constitutes the element principal surface 23. However, the antireflection layer 96 may not be provided. In this case, the light emitting element 20 has the back surface of the element substrate 91 exposed to form the element principal surface 23.

[0063] 3. Detailed explanation of areas 81-83 The main facing region 81, the first sub facing region 82, and the second sub facing region 83 will be described in detail with reference to Fig. 3. The main facing region 81 is a region where the first ceiling 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 facing region 81 is 0.1 to 500 µm, and preferably 0.1 to 100 µm.

[0064] The first sub-facing region 82 is a region 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 closer to the element main surface 23 (the upper portion in FIG. 3). The facing distance H2 of the first sub-facing region 82 is longer than the facing distance H1 of the main facing region 81. The facing distance H2 of the first sub-facing region 82 is 0.1 to 500 μm, preferably 0.1 to 500 μm. In this embodiment, the first sub-facing region 82 faces the side surface of the active layer 92b of the light emitting element 20. However, the side surface of the active layer 92b of the light emitting element 20 is not exposed because it is covered with an insulating layer. Therefore, the side surface of the active layer 92b of the light emitting element 20 faces the first sub-facing region 82 via the insulating layer.

[0065] The second sub-facing region 83 is a region 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 closer to the mounting substrate 10 (the lower portion in FIG. 3). The minimum facing distance H3 of the second sub-facing region 83 is longer than the facing distance H2 of the first sub-facing region 82. For example, the minimum facing distance H3 of the second sub-facing region 83 is at least twice the facing distance H2 of the first sub-facing region 82. The facing distance H3 of the second sub-facing region 83 is 0.1 to 1000 μm, and preferably 50 to 500 μm.

[0066] As shown in FIG. 3, a length L1 in a direction Y perpendicular to the mounting surface 10a of the mounting board 10 in the first sub-facing region 82 is longer than a length L2 in a direction Y perpendicular to the mounting surface 10a of the mounting board 10 in the second sub-facing region 83.

[0067] 4. Details of inactive compounds 60 The inactive compound 60 includes at least one selected from the group consisting of, for example, fluoride compounds, silicon compounds, phosphate compounds, etc. The viscosity of the inactive compound 60 is 0.01 to 50 Pa·s, preferably 0.1 to 50 Pa·s, and more preferably 1 to 50 Pa·s.

[0068] Moreover, the contact angle θ1 (shown in FIG. 5) of the inactive compound 60 with respect to the element main surface 23 at a temperature of 25° C. is 10° to 30°, preferably 17° to 23°, and more preferably 20°. As a result, the inactive compound 60 is held in the main facing region 81 by capillary action. Moreover, the contact angle θ2 (shown in FIG. 3) of the inactive compound 60 with respect to the element side surface 24 at a temperature of 25° C. is 10° to 30°, preferably 17° to 23°, and more preferably 20°. As a result, the inactive compound 60 is held in the first minor facing region 82 by capillary action.

[0069] In particular, the arithmetic mean roughness Ra of the element principal surface 23 and element side surface 24 of the light emitting element 20 is 0.1 to 100,000 nm. This also allows the inactive compound 60 to be held in the main facing region 81 and the first sub-facing region 82 by capillary action. Furthermore, the light emitting element 20 is formed in a shape that does not have any chipping such as a notch or a recess at the boundary between the element principal surface 23 and the element side surface 24, all around the outer periphery of the element principal surface 23. Therefore, the inactive compound 60 is held in the main facing region 81 and the first sub-facing region 82.

[0070] The boiling point of the inactive compound 60 is 150° C. or higher, preferably 200° C. or higher. The junction temperature Tj of the light-emitting element 20 during operation is set to be 150° C. or lower, preferably 100° C. or lower. In particular, the boiling point of the inactive compound 60 is higher than the junction temperature Tj of the light-emitting element 20 during operation by 50° C. or higher, preferably 100° C. or higher. Therefore, even if the temperature of the light-emitting element 20 rises, the inactive compound 60 can be prevented from vaporizing, and the inactive compound 60 can be maintained in the main facing region 81 and the first sub-facing region 82 by the capillary phenomenon.

[0071] The inactive compound 60 has a transmittance of 50% or more, preferably 80% or more, for ultraviolet light having an emission wavelength of 280 nm. Furthermore, the refractive index of the inactive compound 60 is closer to the refractive index of the light-transmitting member 40 than the refractive index of air. The refractive index of the inactive compound 60 is closer to the refractive index of the element substrate 91 (shown in FIG. 2) of the light-emitting element 20 than the refractive index of air. In this embodiment, the refractive index of the inactive compound 60 is preferably greater than the refractive index of air and equal to or less 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 fluorocarbon compound, the refractive index of the fluorocarbon compound is, for example, 1.2 or more and 1.6 or less.

[0072] 5. Boundary shape between the inactive compound 60 and the gas layer 70 The shape of the boundary between the inactive compound 60 and the gas layer 70 will be described with reference to Fig. 3. In this embodiment, the inactive compound 60 is filled in the main facing region 81 and the first sub-facing region 82. Furthermore, a small portion of the inactive compound 60 enters the second sub-facing region 83 from the opening of the first sub-facing region 82. Therefore, the boundary between the inactive compound 60 and the gas layer 70 is located in the second sub-facing region 83.

[0073] The shape of the boundary depends on the viscosity and contact angles θ1, θ2 of the inactive compound 60. In this embodiment, the inactive compound 60 has a predetermined angle with respect to the element side surface 24 of the light emitting element 20 at the boundary. The predetermined angle depends on the contact angle θ2 of the inactive compound 60 with respect to the element side surface 24 and the contact angle of the inactive compound 60 with respect to the second ceiling surface 43a. For example, the predetermined angle has a minimum value of the contact angle θ2 of the inactive compound 60 with respect to the element side surface 24 or the contact angle of the inactive compound 60 with respect to the second ceiling surface 43a, and a maximum value of 45°.

[0074] The boundary functions as a reflector due to the difference in refractive index between the inactive compound 60 and the gas layer 70. That is, a reflector having a predetermined angle is formed on the element side surface 24 of the light emitting element 20. The reflectance at the boundary for ultraviolet light of the emission wavelength is, for example, 50 to 100%.

[0075] Here, the minimum facing distance H3 of the second sub-facing region 83 is equal to or greater than twice the facing distance H2 of the first sub-facing region 82. In this manner, the boundary between the inactive compound 60 and the gas layer 70 is located at a position sufficiently away from the translucent member bonding layer 50. Therefore, the inactive compound 60 is suppressed from flowing to the position of the translucent member bonding layer 50.

[0076] 6. Pathway of ultraviolet light The path of the ultraviolet light emitted by the light-emitting element 20 will be described with reference to Fig. 3. The ultraviolet light emitted in the active layer 92b of the light-emitting element 20 is output from the element principal surface 23 of the light-emitting element 20. The main facing region 81 is filled with an inactive compound 60. Therefore, the light-transmitting member 40 is disposed in the vertical direction of the element principal surface 23 via the inactive compound 60. The emitted ultraviolet light enters the light-transmitting member 40 from the element principal surface 23 via the inactive compound 60, and is output from the light-transmitting member 40 to the outside.

[0077] Here, the inactive compound 60 is in contact with the element principal surface 23, and the inactive compound 60 is in contact with the first ceiling surface 42a of the first recess 42 of the light-transmitting member 40. Therefore, the emitted ultraviolet light is suppressed from being reflected by the element principal surface 23, and is output from the light-transmitting member 40.

[0078] The ultraviolet light emitted from 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 sub-facing region 82 is filled with an inactive compound 60. The emitted ultraviolet light is output from the light-transmitting member 40 via the inactive compound 60 in the first sub-facing region 82 from a portion of the element side surface 24 closer to the element main surface 23.

[0079] Here, the inactive compound 60 is in contact with a portion of the element side surface 24 closer to the element main surface 23, and the inactive compound 60 is in contact with 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 by the element side surface 24 and is output from the light-transmitting member 40.

[0080] Furthermore, a portion of the ultraviolet light output from the element side surface 24 is output toward the boundary between the inactive compound 60 and the gas layer 70. In this embodiment, a portion of the ultraviolet light emitted toward the mounting substrate 10 side of the active layer 92b is output toward the boundary between the inactive compound 60 and the gas layer 70.

[0081] This ultraviolet light has an emission wavelength and is reflected at the boundary between the inactive compound 60 and the gas layer 70. Therefore, a 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, the ultraviolet light is output from the light-transmitting member 40 to the outside.

[0082] In addition, a part 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, the amount of ultraviolet light that passes from the inactive compound 60 to the gas layer 70 is extremely small. Furthermore, a part of the ultraviolet light emitted by the active layer 92b is output to the gas layer 70 from the portion of the element side surface 24 that is in contact with the gas layer 70. However, the amount of ultraviolet light output to the gas layer 70 is extremely small. In this way, the amount of ultraviolet light output to the gas layer 70 is extremely small. Therefore, even if the light-transmitting member bonding layer 50 uses a material that is not very durable against ultraviolet light, such as a silicone resin, the effect is extremely small. Therefore, the light-transmitting member bonding layer 50 can be applied with the above-mentioned inexpensive material.

[0083] 7. Manufacturing method of light emitting device 1 A manufacturing method of the light emitting device 1 will be described with reference to Fig. 4 and Fig. 5. In step S1 shown in Fig. 4, the light emitting element 20 is bonded to the mounting surface 10a of the mounting substrate 10. Then, in step S2, the light-transmitting member bonding layer 50 is placed on the mounting surface 10a of the mounting substrate 10 or the bonding surface of the flange portion 44 of the light-transmitting member 40.

[0084] Next, in step S3, the inactive compound 60 is dropped onto the element principal surface 23 of the light-emitting element 20. At this time, as shown in FIG. 5, the inactive compound 60 remains on the element principal surface 23 of the light-emitting element 20 due to surface tension. The volume of the dropped inactive compound 60 is approximately the same as the total volume of the main facing region 81 and the first sub-facing region 82. In detail, the volume of the dropped inactive compound 60 is slightly larger than the total volume of the main facing region 81 and the first sub-facing region 82. And, the volume of the dropped inactive compound 60 is sufficiently smaller than the total volume of the main facing region 81, the first sub-facing region 82, and the second sub-facing region 83.

[0085] As described above, the contact angle θ1 of the inactive compound 60 dropped onto the element principal surface 23 at a temperature of 25° C. is 10° to 30°, preferably 17° to 23°, and more preferably 20°. Therefore, the inactive compound 60 remains on the element principal surface 23 with a thin thickness.

[0086] 4, the light-transmitting member 40 is placed on the substrate 10 and bonded to the mounting substrate 10 as shown by the arrow P in FIG. 5. At this time, as the element main surface 23 and the first ceiling surface 42a of the first recess 42 of the light-transmitting member 40 approach each other, the inactive compound 60 dropped on the element main surface 23 gradually moves toward the element side surface 24 after contacting the first ceiling surface 42a. The inactive compound 60 that has moved to the element side surface 24 is held in the first minor 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 manner, the light-emitting device 1 shown in FIG. 1 is completed.

[0087] In particular, since the contact angle θ1 of the inactive compound 60 dropped on the element main surface 23 is within the above angle range at a temperature of 25° C., the inactive compound 60 can be maintained in the main facing region 81 at the facing distance H1. Furthermore, since the contact angle θ2 of the inactive compound 60 with respect to the element side surface 24 at a temperature of 25° C. is within the above angle range, the inactive compound 60 can be maintained in the first minor facing region 82 at the facing distance H2.

[0088] 8. Effects Next, a detailed description will be given of the effects of the light emitting device of the present embodiment 1. According to the light emitting device of the present embodiment 1, the inactive compound 60, which is liquid at room temperature and normal pressure, is filled in the main facing region 81 where the element main surface 23 faces the first ceiling surface 42a of the recess 41 of the translucent member 40, and is also filled in the first sub-facing region 82 where the portion of the element side surface 24 close to the element main surface 23 faces the first side wall surface 42b of the recess 41 of the translucent member 40.

[0089] Furthermore, a gas layer 70 is formed in the second sub-facing region 83 facing the portion of the element side surface 24 closer to the mounting substrate 10. As a result, the gas layer 70 formed in the second sub-facing region 83 prevents capillary action from occurring in the second sub-facing region 83, and the liquid inactive compound 60 filled in the main facing region 81 and the first sub-facing region 82 is prevented from flowing out and is retained in the main facing region 81 and the first sub-facing region 82. This prevents a decrease in the extraction efficiency of the ultraviolet light emitted from the element principal surface 23 and improves the extraction efficiency of the ultraviolet light emitted from at least the portion of the element side surface 24 closer to the element principal surface 23, thereby improving the extraction efficiency of the ultraviolet light of the light emitting device 1 as a whole.

[0090] Moreover, in the first embodiment, the facing distance H3 in the second sub-facing region 83 is longer than the facing distance H2 in the first sub-facing region 82. This makes it easier for the inactive compound 60 to be held in the main facing region 81 and the first sub-facing region 82, and also prevents the inactive compound 60 from flowing out to the second sub-facing region 83, so that the ultraviolet light extraction efficiency of the light emitting device 1 as a whole can be further improved.

[0091] Furthermore, in the first embodiment, the inactive compound 60 is held in the main facing region 81 and the first sub-facing region 82 by capillary action. This can improve the retention of the inactive compound 60 in the main facing region 81 and the first sub-facing region 82, further preventing the inactive compound 60 filled in the main facing region 81 and the first sub-facing region 82 from flowing out, and further improving the ultraviolet light extraction efficiency of the light emitting device 1 as a whole.

[0092] In the first embodiment, the facing distance H2 of the first minor facing region 82 is longer than the facing distance H1 of the main facing region 81. This further increases the retention of the inactive compound 60 in the main facing region 81 due to capillary action, and further prevents the inactive compound 60 from flowing out, thereby further improving the ultraviolet light extraction efficiency of the light emitting device 1 as a whole.

[0093] In the first embodiment, the facing distance H1 of the main facing regions 81 is 0.1 to 500 μm, and the facing distance H2 of the first sub-facing regions 82 is 0.1 to 500 μm. This ensures that capillary action occurs in the main facing regions 81 and the first sub-facing regions 82, preventing the inactive compound 60 from leaking out, and further improves the ultraviolet light extraction efficiency of the light emitting device 1 as a whole.

[0094] In the first embodiment, the surface of the element side surface 24 of the light emitting element 20 that forms the first minor facing region 82 has a Ra of 100 μm or less. This reduces the contact angle of the inactive compound 60 with respect to the element side surface 24, thereby reducing wettability. As a result, it is possible to promote retention of the inactive compound 60 in the first minor facing region 82 by capillary action.

[0095] Moreover, in the first embodiment, the light emitting element 20 is formed in a shape that has no chips in the boundary between the element principal surface 23 and the element side surface 24. This can further prevent the inactive compound 60 held in the main facing region 81 and the first sub-facing region 82 from flowing out.

[0096] In the first embodiment, the element side surface 24 of the light emitting element 20 and the first side wall surface 42b of the recess 41 are formed parallel to each other. This makes it possible to prevent the inactive compound 60 held in the main facing region 81 and the first sub-facing region 82 from flowing out.

[0097] In addition, in the first embodiment, the side surface of the active layer 92b of the light emitting element 20 faces the first sub-facing region 82 and faces the inactive compound 60. As a result, compared to the case where the side surface of the active layer 92b that generates ultraviolet light faces the gas layer 70, ultraviolet light emitted from the side surface of the active layer 92b is more likely to enter the light-transmitting member 40 via the inactive compound 60 and be output from the light-transmitting member 40, and the ultraviolet light extraction efficiency of the light emitting device 1 as a whole can be further improved.

[0098] Furthermore, in the first embodiment, the length L1 in the direction Y perpendicular to the mounting surface 10a of the mounting substrate 10 in the first sub-facing region 82 is longer than the length L2 in the direction Y perpendicular to the mounting surface 10a of the mounting substrate 10 in the second sub-facing region 83. This makes it easier for ultraviolet light emitted from the side surface of the active layer 92b of the light-emitting element 20 to enter the light-transmitting member 40 through the inactive compound 60 and be output from the light-transmitting member 40, thereby further improving the ultraviolet light extraction efficiency of the light-emitting device 1 as a whole.

[0099] In the first embodiment, as described above, in order to hold the inactive compound 60 in the main facing region 81 and the first sub-facing region 82, the contact angle θ1 of the inactive compound 60 with respect to the element principal surface 23 at a temperature of 25° C. is set to 10° to 30°. This makes it possible to hold the liquid inactive compound 60 at room temperature and normal pressure in the main facing region 81 between the element principal surface 23 of the light emitting element 20 and the light-transmitting member 40, and to form a gas layer 70 in the region facing the element side surface 24.

[0100] In the first embodiment, the viscosity of the inactive compound 60 at a temperature of 25° C. is set to 0.01 to 50 Ps·s. This allows the contact angle θ1 of the inactive compound 60 with respect to the element principal surface 23 at a temperature of 25° C. to be within the above range. Furthermore, by setting the arithmetic mean roughness Ra of the element principal surface 23 to 0.1 to 100,000 nm, the contact angle θ1 of the inactive compound 60 with respect to the element principal surface 23 at a temperature of 25° C. can be within the above range.

[0101] In the first embodiment, the inactive compound 60 is disposed in the accommodation space 80 in contact with at least a part of the element side surface 24 of the light emitting element 20, and the contact angle θ2 of the inactive compound 60 with respect to the element side surface 24 at a temperature of 25° C. is set to 10° to 30°. This makes it possible to hold the inactive compound 60 in contact with at least a part of the element side surface 24 of the light emitting element 20, and form a gas layer 70 in the region facing the element side surface 24. Furthermore, by setting the arithmetic mean roughness Ra of the element side surface 24 to 0.1 to 100,000 nm, the contact angle θ2 of the inactive compound 60 with respect to the element side surface 24 at a temperature of 25° C. can be set to the above range.

[0102] In the first embodiment, the boiling point of the inactive compound 60 is set to 150° C. or higher. The junction temperature of the light-emitting element during operation is set to 150° C. or lower. Therefore, even when the temperature of the light-emitting element 20 rises during operation, the inactive compound 60 can be held at a desired position.

[0103] In the first embodiment, the inactive compound 60 has a transmittance of 50% or more for ultraviolet light of an emission wavelength, and therefore, when the inactive compound 60 is disposed, the light extraction efficiency of the ultraviolet light can be increased. Furthermore, by making the inactive compound 60 a fluoride compound, the refractive index difference between the light emitting element 20 and the inactive compound 60 and the refractive index difference between the light transmitting member 40 and the inactive compound 60 can be reduced. Therefore, the light extraction efficiency of the ultraviolet light can be increased.

[0104] The light emitting element 20 is a flip chip type that extracts light from the back side of an element substrate 91 included in the light emitting element 20, and the element main surface is located on the back side of the surface of the element substrate on which the semiconductor layer is formed. This allows the inactive compound 60 in a liquid state at room temperature and normal pressure to be held in the main opposing region 81 between the element main surface 23 of the light emitting element 20 and the translucent member 40. In particular, the opposing distance H1 of the main opposing region 81 is 0.1 to 500 μm. This allows the inactive compound 60 in a liquid state to be held in the main opposing region 81 between the element main surface 23 of the light emitting element 20 and the translucent member 40 at room temperature and normal pressure.

[0105] (Embodiment 2) In the present embodiment 1, as shown in Fig. 3, the first sub-facing region 82 faces the side surface of the active layer 92b of the light-emitting element 20, but instead, as in embodiment 2 shown in Fig. 6, the first sub-facing region 82 may not face the side surface of the active layer 92b of the light-emitting element 20, and the second sub-facing region 83 may face the side surface of the active layer 92b of the light-emitting element 20. In the present embodiment 2, the same components as those in embodiment 1 are denoted by the same reference numerals, and the description thereof will be omitted.

[0106] Also in the second embodiment, a part of the ultraviolet light emitted in the active layer 92b of the light-emitting element 20 is incident on the inactive compound 60 in the first sub-facing region 82 from the element side surface 24 of the light-emitting element 20 facing the first sub-facing region 82 of the light-emitting element 20. Then, the light is reflected toward the light-transmitting member 40 by the boundary between the inactive compound 60 and the gas layer 70, and is incident on the light-transmitting member 40 and output to the outside.

[0107] According to the second embodiment, there is a tendency that the amount of ultraviolet light directly emitted from the side surface of the active layer 92b in the second sub-facing region 83 to the gas layer 70 increases, as compared with the first embodiment, and the degree of improvement in the ultraviolet light extraction efficiency of the light emitting device 1 as a whole decreases compared with the first embodiment, but it goes without saying that the ultraviolet light extraction efficiency is improved compared with the case where the inactive compound 60 in the first sub-facing region 82 is not present. Except for the decrease in the degree of improvement in the ultraviolet light extraction efficiency, the second embodiment also exhibits the same effects as the first embodiment.

[0108] (Embodiment 3) In the above-mentioned embodiment 1, as shown in FIG. 1, the outer peripheral edge 10b, which is the joint between the flange portion 44 of the light-transmitting member 40 on the mounting substrate 10, is located on the same plane as the mounting surface 10a. However, this is not limited to this, and a configuration may be used in which the mounting surface 10a is provided at the bottom of a substrate recess 13 that is formed in a concave shape on the mounting substrate 10, and the outer peripheral edge 10b is located outside the substrate recess 13 and is not on the same plane as the mounting surface 10a, as in embodiment 3 shown in FIG. 7.

[0109] In the third embodiment, the side wall surface 13b of the substrate recess 13 faces the element side surface 24, and the region between the side wall surface 13b and the element side surface 24 forms a second sub-facing region 83. The second ceiling surface 13a, which is the upper surface of the second sub-facing region 83, is formed in a flat surface parallel to the mounting surface 10a of the mounting substrate 10. A gas layer 70 is formed in the second sub-facing region 83.

[0110] In the third embodiment, the bonding position between the light-transmitting member 40 and the mounting substrate 10 is located closer to the mounting substrate 10a of the mounting substrate 10 (lower side in FIG. 1) than the position of the active layer 92b of the light-emitting element 20 in the vertical direction Y of the mounting substrate 10a of the mounting substrate 10. That is, the light-transmitting member bonding layer 50 is located closer to the mounting substrate 10a of the mounting substrate 10 than the first minor facing region 82. Furthermore, the light-transmitting member bonding layer 50 is located closer to the mounting substrate 10a of the mounting substrate 10 than the position of the active layer 92b. In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted. The third embodiment also provides the same effects as those in the first embodiment.

[0111] (Embodiment 4) In the above-described first embodiment, the light-transmitting member 40 includes the first recess 42 and the second recess 43, and the region facing the element side surface 24 of the light-emitting element 20 includes the first sub-facing region 82 and the second sub-facing region 83.

[0112] 8, the light-transmitting member 40 may include only the first recess 42, and the region facing the element side surface 24 may include only the first sub-facing region 82. In other words, the facing distance H2 of the first sub-facing region 82 is larger than that of the first embodiment and is equivalent to the second sub-facing region 83 in the first embodiment.

[0113] In this configuration, since the contact angle θ1 of the inactive compound 60 dropped onto the element principal surface 23 at a temperature of 25° C. is within the above-mentioned angle range, the inactive compound 60 is held in the main facing region 81 by capillary action. However, the inactive compound 60 is disposed in contact with a part of the element side surface 24.

[0114] The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the gist of the present invention. [Explanation of symbols]

[0115] 1 Light emitting device 10 Mounting board 10a Mounting surface 10b Outer edge 11 Main body 12 Circuit Pattern 13 Board recess 13a Second ceiling surface 13b Side wall 20 Light emitting element 21, 22 Electrode pads 23 Element main surface 24 Side of element 30 Element bonding layer 40 Translucent material 41 Recess 42 First recess 42a First ceiling surface 42b First side wall 43 Second recess 43a Second ceiling surface 43b Second side wall 44 Flange part 50 Translucent member bonding layer 60 Inert compounds 70 Gas Layer 80 Storage Space 81 Main opposing area 82 1st secondary opposing area 83 2nd secondary opposing area

Claims

1. a mounting substrate having a mounting surface; an ultraviolet light-emitting element disposed on the mounting surface of the mounting substrate, the light-emitting element having a main surface facing the opposite side to the mounting surface and a side surface adjacent to the main surface; a light-transmitting member that is disposed on the mounting surface of the mounting substrate and that forms an accommodation space for accommodating the light-emitting element in an area facing the mounting surface of the mounting substrate; an inactive compound that is liquid at room temperature and normal pressure and that is filled in at least a main opposing region between the main surface of the light-emitting element and the light-transmitting member in the accommodation space; a gas layer formed in a region facing the element side surface in the accommodation space, A light-emitting device, wherein the contact angle of the inactive compound with respect to the main surface of the element at a temperature of 25° C. is 10° to 30°.

2. 2. The light emitting device according to claim 1, wherein the inactive compound has a viscosity of 0.01 to 50 Ps·s at a temperature of 25°C.

3. 2. The light emitting device according to claim 1, wherein the principal surface of the element has an arithmetic mean roughness Ra of 0.1 to 100,000 nm.

4. the inactive compound is disposed in the accommodation space in contact with at least a portion of the element side surface of the light emitting element, 2. The light emitting device according to claim 1, wherein the contact angle of the inactive compound with respect to the side surface of the element at a temperature of 25° C. is 10° to 30°.

5. 5. The light emitting device according to claim 4, wherein the arithmetic mean roughness Ra of the element side surface is 0.1 to 100,000 nm.

6. 6. The light emitting device according to claim 1, wherein the boiling point of the inactive compound is 150° C. or higher.

7. The light emitting device according to claim 6 , wherein a junction temperature of said light emitting element during operation is set to 150° C. or less.

8. 6. The light emitting device according to claim 1, wherein the inactive compound has a transmittance of 50% or more for ultraviolet light having an emission wavelength.

9. The light emitting device according to any one of claims 1 to 5, wherein the inactive compound is a fluorinated compound.

10. The light emitting element is a flip chip type that extracts light from a back side of an element substrate included in the light emitting element, 6. The light emitting device according to claim 1, wherein the element main surface is located on a rear side of a surface of the element substrate on which a semiconductor layer is formed.

11. 6. The light emitting device according to claim 1, wherein the opposing distance between the main opposing regions is 0.1 to 500 μm.

Images