Optical devices

Abstract

To provide an optical device with a low risk of short circuits between substrate electrodes. [Solution] The optical device 1 includes a substrate 10 on which a first substrate electrode 11 and a second substrate electrode 12 disposed at a distance from the first substrate electrode 11 are formed on one side; a light-emitting element 20 having a first element electrode 21 disposed opposite to the first substrate electrode 11 and a second element electrode 22 electrically connected to the second substrate electrode 12, which emits light in a predetermined emission direction when a voltage is applied between the first element electrode 21 and the second element electrode 22; and a connecting member 40 that electrically connects the first substrate electrode 11 and the first element electrode 21. The substrate 30 is disposed at least a portion of the way between the first substrate electrode 11 and the second substrate electrode 12, and has a projection that supports the light-emitting element.

Description

Technical Field

[0005]

[0001] The present invention relates to an optical device.

Background Art

[0002] In an optical device having a light-emitting element that emits each of red light, blue light, and green light, and an optical element in which an optical waveguide or the like is formed, an active alignment method and a passive alignment method are known as methods for aligning between the light-emitting element and the optical element.

[0003] In the passive alignment method, a technique is known in which a protrusion is arranged on a substrate so that the optical axes of the light-emitting element and the optical element coincide, and the light-emitting element is mounted on the protrusion (see, for example, Patent Document 1). Since the technique described in Patent Document 1 can mount the light-emitting element and the optical element on the substrate without aligning between the light-emitting element and the optical element, the manufacturing cost of the optical device can be suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the technique described in Patent Document 1, when adhering between the element electrode and the substrate electrode with a connecting member, in order to increase the adhesion strength between the element electrode and the substrate electrode and improve the reliability by filling the connecting member between the element electrode and the substrate electrode, it is desirable to increase the amount of the connecting member disposed on the substrate electrode. However, when increasing the amount of the connecting member disposed on the substrate electrode, when the connecting member disposed on the substrate electrode melts, there is a risk that the melted connecting member contacts another substrate electrode and the substrate electrodes are short-circuited. <00000三十> The present invention aims to solve these problems and provide an optical device with a low risk of short circuits between substrate electrodes. [Means for solving the problem]

[0007] The optical device according to the present invention comprises a substrate on which a first substrate electrode and a second substrate electrode disposed at a distance from the first substrate electrode are formed on one surface; a light-emitting element having a first element electrode disposed opposite to the first substrate electrode and a second element electrode electrically connected to the second substrate electrode, which emits light in a predetermined emission direction in response to a voltage applied between the first element electrode and the second element electrode; and a connecting member that electrically connects the first substrate electrode and the first element electrode, wherein at least a portion of the substrate is disposed between the first substrate electrode and the second substrate electrode and further has a projection that supports the light-emitting element.

[0008] Furthermore, in the optical device according to the present invention, it is preferable that the protrusion has a first protrusion that supports one end of the light-emitting element such that both ends protrude from the light-emitting element, and a second protrusion that is positioned between the first substrate electrode and the second substrate electrode and supports the other end of the light-emitting element such that both ends protrude from the light-emitting element.

[0009] Furthermore, in the optical device according to the present invention, it is preferable that the projection further includes a third projection disposed between the first substrate electrode and the second substrate electrode such that one end is connected to the first projection and the other end is connected to the second projection.

[0010] Furthermore, in the optical device according to the present invention, the second element electrode is preferably arranged adjacent to the first element electrode and facing the second substrate electrode, and the projection further has a third projection that is arranged between the first substrate electrode and the second substrate electrode and supports the light-emitting element.

[0011] Furthermore, in the optical device according to the present invention, it is preferable that the second substrate electrode is arranged to cover an area other than the area supporting the light-emitting element of the protrusion.

[0012] Furthermore, in the optical device according to the present invention, it is preferable that the protrusion has a creep-up prevention structure on the surface facing the connecting member to prevent the connecting member from creeping up before solidification.

[0013] Furthermore, in the optical device according to the present invention, it is preferable that the protrusions form recesses on which light-emitting elements can be arranged. [Effects of the Invention]

[0014] The optical device according to the present invention can reduce the risk of short circuits between substrate electrodes. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view of an optical device according to an embodiment. [Figure 2] Figure 1 is a plan view of the optical device shown. [Figure 3] This is a diagram (part 1) illustrating the manufacturing process of the optical device shown in Figure 1. [Figure 4] This is a diagram (part 2) illustrating the manufacturing process of the optical device shown in Figure 1. [Figure 5] This is the third diagram illustrating the manufacturing process of the optical device shown in Figure 1. [Figure 6] This is a perspective view of the substrate of the optical device according to the first modified example. [Figure 7] This is a perspective view of the optical device according to the second modified example. [Figure 8] Figure 7 is a perspective view of the light-emitting element shown in Figure 7. [Figure 9] Figure 7 is a perspective view of the substrate of the optical device shown. [Figure 10] This is a perspective view of the substrate of the optical device according to the third modified example. [Figure 11] This is a partially enlarged cross-sectional view of the region enclosed by the dashed line B shown in Figure 10. [Figure 12] This is a partial side view of an optical device relating to the fourth modified example. [Figure 13]It is a cross-sectional view of a portion corresponding to the A-A line in FIG. 2 of the optical device according to the fifth modification. [Figure 14] It is a partial enlarged cross-sectional view of a region surrounded by the dashed-dotted line C shown in FIG. 13.

Embodiments for Carrying out the Invention

[0016] Hereinafter, various embodiments of the present invention will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to those embodiments, and extends to the invention described in the claims and its equivalents.

[0017] The structure of the device 1 according to the embodiment will be described using FIGS. 1 and 2. As shown in FIGS. 1 and 2, the optical device 1 according to the embodiment includes a substrate 10, a light-emitting element 20, an optical element 30, and a connection member 40, and emits light in an emission direction parallel to the arrangement direction of the light-emitting element 20 and the optical element 30. The substrate 10 is formed of a semiconductor material such as silicon (Si), and a first substrate electrode 11 and a second substrate electrode 12 arranged apart from the first substrate electrode 11 are formed on the upper surface, which is one of the upper and lower surfaces of the substrate 10. Further, the substrate 10 has a first protrusion 13 and a second protrusion 14 formed on the upper surface spaced apart in the emission direction. The substrate 10 has the first substrate electrode 11 and the second substrate electrode 12, and the first protrusion 13 and the second protrusion 14 formed on one surface.

[0018] The first substrate electrode 11 and the second substrate electrode 12 are thin-film pattern electrodes formed of, for example, gold (Au) with titanium (Ti) as a base. By disposing an insulating layer formed of an insulating member such as SiO2 between either one of the first substrate electrode 11 and the second substrate electrode 12 and the substrate 10, the first substrate electrode 11 and the second substrate electrode 12 are insulated from each other. Note that instead of disposing an insulating layer between either one of the first substrate electrode 11 and the second substrate electrode 12 and the substrate 10, the substrate 10 may be formed of a high-resistance material.

[0019] Each of the first projection 13 and the second projection 14 has a rectangular planar shape extending in an extension direction perpendicular to the emission direction, and supports the light-emitting element 20 such that both ends protrude from the light-emitting element 20. The first projection 13 supports one end of the light-emitting element 20, and the second projection 14 supports the other end of the light-emitting element 20. The second projection 14, which is part of the projection consisting of the first projection 13 and the second projection 14, is positioned between the first substrate electrode 11 and the second substrate electrode 12. The first projection 13 and the second projection 14 are formed, for example, by forming an SiO2 layer by flame deposition, and then half-etching the formed SiO2 layer by an etching process such as photolithography, so that the height of the optical waveguides of the light-emitting element 20 and the optical element 30 match. The first projection 13 and the second projection 14 may be formed by etching the substrate 10 by an etching process such as photolithography, or by stacking SiO2 layers by sputtering and vapor deposition.

[0020] The light-emitting element 20 has a first element electrode 21 and a second element electrode 22. The first element electrode 21 is electrically connected to the first substrate electrode 11 via a connecting member 40, and the second element electrode 22 is electrically connected to the second substrate electrode 12 via a bonding wire 15 made of a metallic material such as gold, aluminum, and copper. In this embodiment, the first element electrode 21 is the anode, and the second element electrode 22 is the cathode. The light-emitting element 20 is an end-face emission type semiconductor laser that emits light in the emission direction by applying a predetermined voltage between the first element electrode 21 and the second element electrode 22 via the first substrate electrode 11 and the second substrate electrode 12. The wavelength of the light emitted from the light-emitting element 20 may be visible light, ultraviolet light, or infrared light. The light-emitting element 20 may also be a light-emitting element other than a semiconductor laser, such as an LED.

[0021] The optical element 30 has an optical waveguide and the like formed to guide the light emitted from the light-emitting element 20, and is arranged adjacent to the light-emitting element 20 in the direction of emission. The optical element 30 has an underclad layer which is an SiO2 layer formed by, for example, flame deposition, an optical waveguide which is a Ge-doped SiO2 layer patterned and arranged on the underclad layer, and an overclad layer which is an SiO2 layer deposited on the optical waveguide.

[0022] The connecting member 40 is formed from a metal material such as solder and gold-tin alloy (AuSn), as well as a thermosetting material that is at least partially solid at room temperature, such as epoxy silver paste and sintering paste, and is placed between the first substrate electrode 11 and the first element electrode 21. The connecting member 40 solidifies from a state in which at least a portion is melted by heating, that is, it passes through a liquid state during the solidification process, thereby physically and electrically connecting the first substrate electrode 11 and the first element electrode 21. The connecting member 40 may be pre-placed on one side of the substrate 10 by a film formation process such as plating, vapor deposition, and sputtering, or it may be placed on one side of the substrate 10 by coating and printing processes when mounting the light-emitting element 20 to the substrate 10.

[0023] The manufacturing process of the optical device 1 will be explained with reference to Figures 3 to 5. First, in the substrate preparation process shown in Figure 3, the substrate 10 is prepared. The substrate 10 has the first substrate electrode 11 and the second substrate electrode 12, as well as the first projection 13 and the second projection 14, on which the optical element 30 and the connecting member 40 are arranged. The connecting member 40 is in its pre-melting state, is positioned between the first projection 13 and the second projection 14, and has a rectangular planar shape. The height of the connecting member 40 is greater than the height of the first projection 13 and the second projection 14.

[0024] Next, in the light-emitting element placement process shown in Figure 4, the light-emitting element 20 is aligned by an alignment device (not shown) so that its optical axis coincides with the optical axis of the optical element 30 in the emission direction, and is placed on the connecting member 40. Since the height of the connecting member 40 is greater than the height of the first projection 13 and the second projection 14, in the light-emitting element placement process, the light-emitting element 20 is supported by the connecting member 40 and not by the first projection 13 and the second projection 14.

[0025] Next, in the light-emitting element connection process shown in Figure 5, the connecting member 40 is heated via both the substrate 10 and the light-emitting element 20, causing the connecting member 40 to melt. As the connecting member 40 melts and spreads, the light-emitting element 20, which is pushed down toward the substrate 10 by an alignment device (not shown), is supported by the first projection 13 and the second projection 14. By being supported by the first projection 13 and the second projection 14, the light-emitting element 20 is aligned so that its optical axis coincides with the optical axis of the optical element 30 in both the emission direction and the height direction. Heating is stopped while the light-emitting element 20 is supported by the first projection 13 and the second projection 14, and the connecting member 40 hardens as the temperatures of the substrate 10, light-emitting element 20, and connecting member 40 return to room temperature. As the connecting member 40 hardens, the light-emitting element 20 is fixed in a state where its optical axis coincides with that of the optical element 30, and the first substrate electrode 11 and the first element electrode 21 are physically and electrically connected. Furthermore, even when the connecting member 40 is formed from a thermosetting material such as epoxy silver paste and sintering paste, it is aligned so that the light-emitting element 20 and the optical element 30 coincide when the light-emitting element 20 is supported by the first projection 13 and the second projection 14.

[0026] In the optical device 1, the second projection 14 is positioned between the first substrate electrode 11 and the second substrate electrode 12 on which the connecting member 40 is placed. In the optical device 1, since the second projection 14 is positioned between the first substrate electrode 11 and the second substrate electrode 12, it is possible to prevent the connecting member 40, which has become molten during the light-emitting element connection process, from wetting and spreading from the first substrate electrode 11 to the second substrate electrode 12. By preventing the connecting member 40, which has become molten during the light-emitting element connection process, from wetting and spreading from the first substrate electrode 11 to the second substrate electrode 12, the optical device 1 can reduce the risk of a short circuit between the first substrate electrode 11 and the second substrate electrode 12.

[0027] Furthermore, by positioning the second projection 14 between the first substrate electrode 11 and the second substrate electrode 12, the optical device 1 can reduce the risk of short circuits even when the separation distance between the first substrate electrode 11 and the second substrate electrode 12 is shortened. By shortening the separation distance between the first substrate electrode 11 and the second substrate electrode 12, the longitudinal length of the substrate 10 of the optical device 1 can be shortened, enabling miniaturization.

[0028] Referring to Figure 6, the structure of the substrate of the optical device according to the first modified example will be described. Figure 6 is a perspective view of the substrate 50 according to the first modified example corresponding to Figure 3, in which a connecting member 40 in its pre-melting state is placed on the first substrate electrode 11 between the first projection 13 and the second projection 14. The substrate 50 differs from the substrate 10 in that the second substrate electrode 51 is formed on one side instead of the second substrate electrode 12. The substrate 50 also differs from the substrate 10 in that a projection 52 having a U-shaped planar shape is formed instead of the first projection 13 and the second projection 14. The components and functions of the substrate 50 other than the formation of the second substrate electrode 51 and the projection 52 are the same as those of the substrate 10, so a detailed explanation is omitted here.

[0029] The second substrate electrode 51 differs from the second substrate electrode 12 in its planar shape. The second substrate electrode 51 also differs from the second substrate electrode 12 in that it has an extended portion 51a that is arranged to sandwich the light-emitting element 20 parallel to the first substrate electrode 11 in the emission direction. The configuration and function of the second substrate electrode 51 other than its planar shape are the same as those of the second substrate electrode 12, so a detailed explanation is omitted here.

[0030] The projection 52 has a first projection 53, a second projection 54, and a third projection 55. The first projection 53 and the second projection 54, like the first projection 13 and the second projection 14, have a rectangular planar shape extending in an extension direction perpendicular to the emission direction, and support the light-emitting element 20 such that both ends protrude from the light-emitting element 20. The third projection 55 has one end connected to the first projection 53 and the other end connected to the second projection 54, has a rectangular planar shape extending parallel to the emission direction, and is positioned between the first substrate electrode 11 where the connecting member 40 is located and the extended portion 51a of the second substrate electrode 51.

[0031] In the substrate 50 according to the first modified example, the second substrate electrode 51 has an extended portion 51a, which makes the separation distance between the second substrate electrode 51 and the second element electrode 22 shorter than that of the substrate 10, and shortens the length of the bonding wire connecting the second substrate electrode 51 and the second element electrode 22. In the substrate 50 according to the first modified example, shortening the length of the bonding wire connecting the second substrate electrode 51 and the second element electrode 22 enables miniaturization of the optical device, reduces the resistance between the second substrate electrode 51 and the second element electrode 22, and improves the response speed.

[0032] Furthermore, in the substrate 50 according to the first modified example, the third projection 55 is positioned between the first substrate electrode 11 and the extended portion 51a, thereby reducing the risk of short-circuiting between the first substrate electrode 11 and the second substrate electrode 12, even if the area of ​​the second substrate electrode 51 is larger than that of the second substrate electrode 12.

[0033] The optical device according to the second modified example will be described with reference to Figures 7-9. Optical device 2 differs from optical device 1 in that it has a substrate 60, a first connecting member 41, a second connecting member 42, and a light-emitting element 25 instead of the substrate 10, the connecting member 40, and the light-emitting element 20. The configuration and function of the components of optical device 2 other than the substrate 60 and the light-emitting element 25 are the same as those of the components of optical device 1 which are given the same reference numerals, so a detailed explanation is omitted here.

[0034] As shown in Figure 8, the light-emitting element 25 is a flip-chip type light-emitting element having a first element electrode 26, also called a first element electrode, and a second element electrode 27, also called a second element electrode, which is arranged adjacent to the first element electrode 26 on the same plane as the first element electrode 26. In this embodiment, the first element electrode 21 is the anode and the second element electrode 22 is the cathode.

[0035] The first connecting member 41 and the second connecting member 42 are formed from metal materials such as solder and gold-tin alloy (AuSn), as well as thermosetting materials such as epoxy silver paste and sintering paste, similar to the connecting member 40.

[0036] The structure of the substrate 60 will be described with reference to Figure 9. Figure 9 is a perspective view of the substrate 60 according to a second modified example corresponding to Figure 3. The substrate 60 differs from the substrate 10 in that the first substrate electrode 61 and the second substrate electrode 62 are formed on one side instead of the first substrate electrode 11 and the second substrate electrode 12. The substrate 50 also differs from the substrate 10 in that a third projection 63 is formed between the first projection 13 and the second projection 14. The components and functions of the substrate 60 other than the formation of the first substrate electrode 61, the second substrate electrode 62 and the third projection 63 are the same as those of the substrate 10, so a detailed explanation is omitted here.

[0037] The first substrate electrode 61 and the second substrate electrode 62 each have a different planar shape from the first substrate electrode 11 and the second substrate electrode 12. The first substrate electrode 61 is positioned such that the area where the first connecting member 41 is placed faces the first element electrode 26. The second substrate electrode 62 is positioned such that the area where the second connecting member 42 is placed faces the second element electrode 27. The first substrate electrode 61 is connected to the first element electrode 26 via the first connecting member 41, and the second substrate electrode 62 is connected to the second element electrode 27 via the second connecting member 42.

[0038] The third projection 63, like the first projection 13 and the second projection 14, has a rectangular planar shape extending in an extension direction perpendicular to the emission direction, and is positioned between the first connecting member 41 and the second connecting member 42, supporting the light-emitting element 25 such that both ends protrude from the light-emitting element 20.

[0039] In optical device 2, the third projection 63 is positioned between the first connecting member 41 and the second connecting member 42. In optical device 1, since the third projection 63 is positioned between the first connecting member 41 and the second connecting member 42, it is possible to prevent the first connecting member 41 and the second connecting member 42, which have become molten during the light-emitting element connection process, from wetting and spreading, thus preventing a short circuit. By preventing the first connecting member 41 and the second connecting member 42, which have become molten during the light-emitting element connection process, from short-circuiting, optical device 1 can reduce the risk of a short circuit between the first substrate electrode 61 and the second substrate electrode 62.

[0040] The structure of the substrate of the optical device according to the third modified example will be described with reference to Figures 10 and 11. Figure 10 is a perspective view of the substrate 70 according to the first modified example, which corresponds to Figure 3. The substrate 70 differs from the substrate 10 in that the second substrate electrode 71 is formed on one side instead of the second substrate electrode 12. The substrate 70 also differs from the substrate 10 in that a projection 72 is formed instead of the first projection 13 and the second projection 14. The components and functions of the substrate 70 other than the formation of the second substrate electrode 71 and the projection 72 are the same as those of the substrate 10, so a detailed explanation is omitted here.

[0041] The second substrate electrode 71 differs from the second substrate electrode 12 in its planar shape and placement position. The second substrate electrode 71 differs from the second substrate electrode 12 in that it has an extended portion 71a that is arranged parallel to the first substrate electrode 11 in the emission direction, sandwiching the light-emitting element 20. Also, the second substrate electrode 71 differs from the second substrate electrode 12 in that it is arranged on the substrate 50 via a projection 72. The configuration and function of the second substrate electrode 71 are the same as those of the second substrate electrode 12, other than the planar shape and placement position, so a detailed explanation is omitted here.

[0042] The projection 72 has a first projection 73, a second projection 74, a third projection 75, and a fourth projection 76. The first projection 73 and the second projection 74, like the first projection 13 and the second projection 14, have a rectangular planar shape extending in an extension direction perpendicular to the emission direction and support the light-emitting element 20. The third projection 75 has one end connected to the first projection 73 and the other end connected to the second projection 74, and is positioned so as to be in contact with the longitudinal end of the substrate 70, has a rectangular planar shape extending parallel to the emission direction, and is positioned between the substrate 70 and the second substrate electrode 71. The fourth projection 76 has a rectangular planar shape with one end in contact with the first projection 73 and the third projection 75 and the other end in contact with the short-side end of the substrate 70, and is positioned between the substrate 70 and the second substrate electrode 71. In the projection 72, the second substrate electrode 71 is positioned to cover the third projection 75 and the fourth projection 76, which are areas other than the first projection 73 and the second projection 74 that support the light-emitting element 20.

[0043] As shown in Figures 10 and 11, in the substrate 70, the first substrate electrode 11 is placed directly on the substrate 70, while the second substrate electrode 71 is placed on the substrate 70 via a projection 72. In the substrate 70, since the second substrate electrode 71 is placed on the substrate 70 via a projection 72, it is possible to prevent the connecting member 40, which becomes molten during the light-emitting element connection process, from wetting and spreading from the first substrate electrode 11 to the second substrate electrode 71. By preventing the connecting member 40, which becomes molten during the light-emitting element connection process, from wetting and spreading from the first substrate electrode 11 to the second substrate electrode 71, the risk of a short circuit between the first substrate electrode 11 and the second substrate electrode 71 can be reduced.

[0044] In addition, in the optical device according to the embodiment, the protrusion may have a creep-up prevention structure on the surface facing the connecting member to prevent the connecting member from creeping up before solidification.

[0045] For example, as shown in Figure 12, the second projection 14 may have a tapered structure 14a formed on the surface facing the connecting member 40 as an anti-climbing structure. The tapered structure 14a is formed so as it moves away from the surface of the substrate 10, the horizontal distance between it and the first substrate electrode 11 which is positioned opposite it decreases, and it covers the connecting member 40. In the example shown in Figure 12, the anti-climbing structure is a tapered structure 14a, but in the optical device according to this embodiment, the anti-climbing structure may be a curved surface or a rough surface that is positioned to cover the connecting member 40.

[0046] Furthermore, in the optical device according to the embodiment, the protrusion may have a recess formed therein on which a light-emitting element can be arranged.

[0047] For example, as shown in Figures 13 and 14, the second projection 14 may have a recess 14b in which the light-emitting element 20 can be placed. When the recess 14b is formed in the second projection 14, the first projection 13 will also have a recess in which the light-emitting element 20 can be placed, similar to the second projection 14. By forming recesses in the first projection 13 and the second projection 14 in which the light-emitting element 20 can be placed, the separation distance between the first substrate electrode 11 and the second substrate electrode 12 is increased. By increasing the separation distance between the first substrate electrode 11 and the second substrate electrode 12, the risk of the molten connecting member reaching the second substrate electrode 12 and causing a short circuit between the first substrate electrode 11 and the second substrate electrode 12 can be reduced. In addition, by forming recesses in the first projection 13 and the second projection 14 in which the light-emitting element 20 can be placed, the positioning of the light-emitting element 20 in the emission direction becomes easier.

[0048] Furthermore, although the described optical device has a single light-emitting element and a single optical element, the optical device according to the embodiment may have two or more light-emitting elements that emit the same or different light, such as red, green, and blue. Also, the optical device according to the embodiment may have two or more optical elements that have the same or different functions. [Explanation of Symbols]

[0049] 1, 2 Optical devices 10, 50, 60, 70 circuit boards 11, 61 1st substrate electrode 12, 51, 62, 71 2nd substrate electrode 13, 53, 73 1st protrusion 14, 54, 74 2nd protrusion 20, 25 Light-emitting elements 40 Connecting Members 52, 72 protrusion

Claims

1. A substrate having a first substrate electrode and a second substrate electrode positioned spaced apart from the first substrate electrode formed on one side, A light-emitting element has a first element electrode positioned opposite the first substrate electrode and a second element electrode electrically connected to the second substrate electrode, and emits light in a predetermined emission direction in response to a voltage being applied between the first element electrode and the second element electrode, The device comprises a connecting member that electrically connects the first substrate electrode and the first element electrode, The optical device is characterized in that at least a portion of the substrate is disposed between the first substrate electrode and the second substrate electrode, and a projection supporting the light-emitting element is further formed thereon.

2. The aforementioned protrusion is A first projection supports one end of the light-emitting element such that both ends protrude from the light-emitting element, A second projection is positioned between the first substrate electrode and the second substrate electrode, supporting the other end of the light-emitting element such that both ends protrude from the light-emitting element, The optical device according to claim 1, having the following features.

3. The optical device according to claim 2, wherein the projection further comprises a third projection disposed between the first substrate electrode and the second substrate electrode such that one end of the projection is connected to the first projection and the other end is connected to the second projection.

4. The second element electrode is positioned adjacent to the first element electrode and facing the second substrate electrode. The optical device according to claim 2, wherein the projection is disposed between the first substrate electrode and the second substrate electrode and further comprises a third projection that supports the light-emitting element.

5. The optical device according to claim 1, wherein the second substrate electrode is arranged to cover an area of ​​the protrusion other than the area supporting the light-emitting element.

6. The optical device according to any one of claims 1 to 5, wherein the projection has a creep-up prevention structure on the surface facing the connecting member to prevent the connecting member from creeping up before solidification.

7. The optical device according to any one of claims 1 to 5, wherein the projection has a recess formed therein in which the light-emitting element can be arranged.

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