Patent Application
20230198221
The present disclosure relates to a semiconductor light-emitting device and a light source device.
A semiconductor light-emitting device has been proposed in which a semiconductor light-emitting element such as a semiconductor laser element is mounted above a substrate and a cap covers the semiconductor light-emitting element (see Patent Literature (PTL) 1 and 2, etc., for example).
A configuration in which a semiconductor laser element is mounted above a substrate via a submount, and a cap that covers the semiconductor laser element is disposed above the substrate is proposed in PTL 1 and 2. A transparent plate for extracting out laser light is provided on a side surface of the cap.
According to PTL 1 and 2, the heat dissipation property of the semiconductor laser element is enhanced by the submount and the substrate, and the cap hermetically seals the semiconductor laser element, thereby trying to enhance the reliability of the semiconductor laser element.
In such a configuration as described in PTL 1 and 2, the increase in optical output of the semiconductor light-emitting element disposed inside the cap requires a large amount of current to be supplied to the semiconductor light-emitting element. For this reason, it is necessary to use, as wiring for supplying current to the semiconductor light-emitting element, a wiring having a large cross-sectional area which is suitable to supply a large amount of current, i.e., wiring with low resistance. When such a wiring having a large cross-sectional area is disposed above the substrate, the wiring having a large cross-sectional area is placed between the cap and the substrate, and thus a gap is created between the cap and the substrate. This makes it difficult to seal the gap between the cap and the substrate. In order to avoid such a problem, the wiring could be disposed inside the substrate, but this makes the configuration of the substrate complicated and increases costs.
The present disclosure solves such problems and provides a semiconductor light-emitting device, etc. having a simplified configuration and capable of achieving an increase in optical output and enhanced reliability of the semiconductor light-emitting element.
In order to solve the above-described problems, a semiconductor light-emitting device according to one aspect of the present disclosure includes a wiring substrate; a semiconductor light-emitting element disposed above an upper surface of the wiring substrate; and a cap unit which is disposed above the upper surface of the wiring substrate and covers the semiconductor light-emitting element. In the semiconductor light-emitting device, the wiring substrate includes: a first substrate; a first metal layer and a second metal layer that are spaced apart from each other above the first substrate; and a spacer layer disposed above the first substrate, the cap unit includes a bonding surface which is bonded to the wiring substrate, the bonding surface intersecting the first metal layer and the second metal layer in a top view of the wiring substrate, and the spacer layer is disposed between the bonding surface and the first substrate, at a position different from positions of the first metal layer and the second metal layer.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the wiring substrate may further include a first insulating layer disposed above the upper surface of the first substrate, and the first metal layer, the second metal layer, and the spacer layer may be disposed above the first insulating layer.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the first substrate may be a metal substrate.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the metal substrate may comprise a metal flat plate.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the first insulating layer may include an opening, and the semiconductor light-emitting element may be disposed in the opening.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the spacer layer may be disposed along the bonding surface.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the wiring substrate may include a second insulating layer that covers at least one of a portion of the first metal layer, a portion of the second metal layer, or a portion of the spacer layer.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the spacer layer may comprise a metal material.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the spacer layer may comprise a material that one of the first metal layer or the second metal layer includes, and may be electrically connected to the one of the first metal layer or the second metal layer.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the cap unit may include a top plate which is rectangular, and four side walls each connected to a corresponding one of four sides at a peripheral edge of the top plate, one of the four side walls may be a light-transmissive window including an inorganic light-transmissive plate and an antireflection film disposed on the inorganic light-transmissive plate, and emitted light from the semiconductor light-emitting element may pass through the light-transmissive window.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the top plate may be transparent.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, a gap between the light-transmissive window and an emission surface of the semiconductor light-emitting element may be greater than zero and less than a thickness of the light-transmissive window.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, among the four side walls, side walls other than the light-transmissive window may each have a thickness greater than the thickness of the light-transmissive window.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the cap unit may include a top plate which is rectangular, and four side walls each connected to a corresponding one of four sides at a peripheral edge of the top plate, the top plate may be a light-transmissive window including an inorganic light-transmissive plate and an antireflection film disposed on the inorganic light-transmissive plate, and emitted light from the semiconductor light-emitting element may pass through the light-transmissive window.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the semiconductor light-emitting device may include a reflective optical element, and the emitted light from the semiconductor light-emitting element may be reflected by the reflective optical element, and propagate in a direction perpendicular to the upper surface of the wiring substrate.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the semiconductor light-emitting device may include a functional element disposed above the wiring substrate.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the functional element may be covered by the cap unit.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the functional element may be a temperature sensing element.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the temperature sensing element may be disposed at a position at which the temperature sensing element does not intersect an optical axis of the semiconductor light-emitting element.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the semiconductor light-emitting device may further include a shielding component disposed between the temperature sensing element and the semiconductor light-emitting element.
In addition, in one aspect of the semiconductor light-emitting device according to the present disclosure, the first substrate may include a slanted cut surface at an end portion.
In addition, in order to solve the above-described problems, a light source device according to one aspect of the present disclosure includes the above-described semiconductor light-emitting device, a heat sink on which the semiconductor light-emitting device is disposed, and a fixing screw that fixes the semiconductor light-emitting device to the heat sink. In the light source device, the wiring substrate includes a through-hole, and the fixing screw penetrates through the through-hole and is fixed to the heat sink.
In addition, the light source device according to one aspect of the present disclosure may include a cable including a terminal, and a terminal fixing screw. In the light source device, the wiring substrate may include an extraction electrode electrically connected to the first metal layer, the extraction electrode may include an electrode through-hole at a center portion, the terminal fixing screw may penetrate through the electrode through-hole, the terminal may be disposed between the terminal fixing screw and the extraction electrode, and the extraction electrode and the terminal may be electrically connected to each other.
According to the present disclosure, it is possible to provide a semiconductor light-emitting device, etc. having a simplified configuration and capable of achieving an increase in optical output and enhanced reliability of the semiconductor light-emitting element.
These and other advantages and features will become apparent from the following description thereof taken in conjunction with the accompanying Drawings, by way of non-limiting examples of embodiments disclosed herein.
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be noted that each of the embodiments described below shows a specific example of the present disclosure. Therefore, numerical values, shapes, materials, structural components, the arrangement and connection of the structural components, etc. indicated in the following embodiments are mere examples, and are not intended to limit the scope of the present disclosure.
In addition, each of the diagrams is a schematic diagram and thus is not necessarily strictly illustrated. Therefore, the scale sizes and the like are not necessarily exactly represented in each of the diagrams. In each of the diagrams, substantially the same structural components are assigned with the same reference signs, and redundant descriptions will be omitted or simplified.
Moreover, in the present specification, the terms “above” and “below” do not refer to the vertically upward direction and vertically downward direction in terms of absolute spatial recognition, but are used as terms defined by relative positional relationships based on the layering order in a layered configuration. Furthermore, the terms “above” and “below” are applied not only when two structural components are disposed with a gap therebetween or when a separate structural component is interposed between two structural components, but also when two structural components are disposed in contact with each other.
A semiconductor light-emitting device according to Embodiment 1 will be described below.
First, the overall configuration of the semiconductor light-emitting device according to the present embodiment will be described with reference to
Semiconductor light-emitting device 10 according to the present embodiment is a device that emits light, and includes wiring substrate 20, semiconductor light-emitting element 41, and cap unit 50, as illustrated in
Wiring substrate 20 is a plate-like component which serves as a base of semiconductor light-emitting device 10, and is provided with wiring. Upper surface 20a of wiring substrate 20 is a component mounting surface. A lower surface facing away from upper surface 20a (i.e., the surface located on the back side of upper surface 20a) is heat-dissipating surface 20b. As illustrated in
According to the present embodiment, wiring substrate 20 includes through-holes 28a and 28b and positioning holes 29a and 29b. Through-holes 28a and 28b are holes for inserting a fixing component such as a screw when fixing wiring substrate 20 to closely adhere to a heat sink or the like. Through-holes 28a and 28b are located on one side and the other side of wiring substrate 20, respectively, relative to the region in which semiconductor light-emitting element 41 is disposed. It should be noted that, in the following description, the upward direction and the downward direction of
Positioning holes 29a and 29b are holes for positioning wiring substrate 20 to a heat sink or the like when fixing wiring substrate 20 to the heat sink or the like. For example, positioning pins provided on a heat sink or the like at the positions where positioning holes 29a and 29b are to be arranged are fitted into positioning holes 29a and 29b, respectively. This allows positioning wiring substrate 20 at a predetermined position of a heat sink or the like. According to the present embodiment, positioning hole 29a is a first positioning hole and has a circular shape in a top view of wiring substrate 20. Positioning hole 29b is a second positioning hole and has a long hole shape (i.e., an ellipse shape) in the top view of wiring substrate 20.
Metal substrate 28 is an example of a first substrate that wiring substrate 20 includes. Metal substrate 28 comprises a flat plate of metal such as oxygen-free copper or copper alloy. Here, the flat plate is a plate which does not have a patterned unevenness shape with a depth or height greater than the surface roughness on the surface other than the peripheral portion. Since the upper surface of metal substrate 28 is flat, first insulating layer 21 which is flat can be formed above metal substrate 28. This facilitates the formation of a thick metal layer above first insulating layer 21. Metal substrate 28 is, for example, a flat plate that comprises oxygen-free copper having a thickness of approximately greater than or equal to 0.5 mm and less than or equal to 3 mm. The shape of metal substrate 28 (i.e., shape in top view) is, for example, rectangular, and the length of one side of metal substrate 28 is, for example, approximately greater than or equal to 5 mm and less than or equal to 30 mm. According to the present embodiment, slanted cut surface 28c which is a slanted surface that is slanted with respect to the main surface of metal substrate 28 is formed at the edge of metal substrate 28. First insulating layer 21 is formed above the upper surface of metal substrate 28, and no insulating layer is formed above the lower surface of metal substrate 28 (i.e., the surface located on the back side of the upper surface). Accordingly, the entire area of the lower surface of metal substrate 28 can be used as heat-dissipating surface 20b of wiring substrate 20, and thus it is possible to dissipate heat over a large area. As a result, it is possible to use semiconductor light-emitting element 41 which is high in optical output and large in the amount of heat generation.
First insulating layer 21 is an insulating layer that is disposed above the upper surface of metal substrate 28, as illustrated in
First insulating layer 21 includes opening 21a as illustrated in
First metal layer 31, second metal layer 32, third metal layer 33, and fourth metal layer 34 are metal layers that are spaced apart from each other above the first substrate, and are disposed above first insulating layer 21 according to the presented embodiment. First metal layer 31 and second metal layer 32 are wiring for supplying power to semiconductor light-emitting element 41. Third metal layer 33 and fourth metal layer 34 are wiring connected to temperature sensing element 60. Each of the metal layers forms protrusion above first insulating layer 21. First metal layer 31, second metal layer 32, third metal layer 33, and fourth metal layer 34 are metal layers comprising copper, for example, having a thickness approximately greater than or equal to 0.02 mm and less than or equal to 0.15 mm.
Spacer layers 30a and 30b are layers disposed at positions different from the positions of first metal layer 31 and second metal layer and 32 above the first substrate, and disposed above first insulating layer 21 according to the present embodiment. Spacer layers 30a and 30b are disposed between first insulating layer 21 and bonding surface 50b of cap unit 50 with wiring substrate 20 as illustrated in
According to the present embodiment, spacer layers 30a and 30b are disposed only between bonding surface 50b and the first substrate above the first substrate. As illustrated in
According to the present embodiment, spacer layer 30a is disposed linearly along bonding surface 50b that has a loop shape in the top view of wiring substrate 20. Spacer layer 30b is disposed in a C-shape along bonding surface 50b that has a loop shape in the top view of the wiring substrate 20.
The materials that spacer layers 30a and 30b comprise are not particularly limited. According to the present embodiment, spacer layers 30a and 30b comprise a metal material. Spacer layers 30a and 30b are metal layers that comprise copper having a thickness approximately greater than or equal to 0.02 mm and less than or equal to 0.15 mm, as with first metal layer 31, for example.
Second insulating layer 22 is an insulating layer disposed above first insulating layer 21. Second insulating layer 22 covers at least a portion of first metal layer 31, second metal layer 32, third metal layer 33, fourth metal layer 34, and spacer layers 30a and 30b, and also has a function of protecting each of the layers. Second insulating layer 22 is an insulating layer that comprises, for example, resin such as polyimide, epoxy, or the like having a thickness approximately greater than or equal to 0.05 mm and less than or equal to 0.2 mm.
Protection film 25 is a metal film disposed, for example, at a position at which submount 45, etc. are bonded in wiring substrate 20. According to the present embodiment, protection film 25 is disposed in a region of metal substrate 28 corresponding to opening 21a of first insulating layer 21. Protection film 35 is a metal film disposed above a surface where a metal layer such as first metal layer 31 is exposed from second insulating layer 22. Protection film 35 is disposed above a portion of the upper surface of first metal layer 31, second metal layer 32, third metal layer 33, and fourth metal layer 34, etc. Protection films 25 and 35 also serve as anti-corrosion films that protect the exposed surfaces or the like of metal substrate 28, first metal layer 31, etc., from oxidation and the like. Protection films 25 and 35 comprise Ni, Au, or the like, for example.
First pad electrode 31p and second pad electrode 32p are pad-shaped electrodes disposed above the portions of first metal layer 31 and second metal layer 32, respectively, which are adjacent to semiconductor light-emitting element 41. As illustrated in
Semiconductor light-emitting element 41 is a light-emitting element disposed above upper surface 20a of wiring substrate 20. Semiconductor light-emitting element 41 is disposed in opening 21a of first insulating layer 21. Semiconductor light-emitting element 41 is a light-emitting element including a compound semiconductor such as gallium nitride or gallium arsenide, for example. According to the present embodiment, semiconductor light-emitting element 41 is a semiconductor laser element including an optical waveguide that extends in a direction parallel to the main surface of metal substrate 28.
As illustrated in
As illustrated in
Semiconductor light-emitting element 41 has, for example, a rectangular parallelepiped shape with a width approximately greater than or equal to 0.2 mm and less than or equal to 2 mm, a length approximately greater than or equal to 1 mm and less than or equal to 9 mm, and a thickness approximately greater than or equal to 0.08 mm and less than or equal to 0.2 mm.
Submount 45 is a component disposed between wiring substrate 20 and semiconductor light-emitting element 41. Submount 45 is mounted above upper surface 20a of wiring substrate 20. More specifically, as illustrated in
In semiconductor light-emitting device 10 according to the present embodiment, semiconductor light-emitting element 41 is mounted above metal substrate 28 via submount 45 as described above. With such a configuration as described above, it is possible to efficiently dissipate the heat generated in semiconductor light-emitting element 41 through submount 45 to metal substrate 28, as indicated by the arrows in
Cap unit 50 is a cover component that is disposed above upper surface 20a of wiring substrate 20 and covers semiconductor light-emitting element 41 as illustrated in
Holder 52 comprises glass, for example. Holder 52 is manufactured by, for example, forming a recess in a glass block having a rectangular parallelepiped shape, by sandblasting or the like, and dividing it.
Side wall 51 which is a light-transmissive window and holder 52 are bonded by optical contact or laser bonding to form a cap unit having a box shape.
As a result of cap unit 50 having the configuration described above, emitted light L1 from the semiconductor light-emitting element can be easily extracted from side wall 51 of cap unit 50 to the outside.
Thickness Dg of side wall 51 which is a light-transmissive window illustrated in
The thickness of each of side walls 52a, 52b, and 52c is greater than the thickness of side wall 51 which is the light-transmissive window. With this configuration, it is possible to increase the structural strength of the holder and cap unit 50 while reducing the distance (Dg+Dgap) from light-emitting point 41e of semiconductor light-emitting element 41 to the outside of cap unit 50.
Semiconductor light-emitting device 10 may include a functional element other than semiconductor light-emitting element 41. According to the present embodiment, semiconductor light-emitting device 10 includes temperature sensing element 60 as one example of the functional element. The following describes temperature sensing element 60 that is one example of the functional element. Temperature sensing element 60 is a temperature sensor that is disposed above wiring substrate 20. As illustrated in
Connector 70 is a connecting component including terminals each of which is connected to a corresponding one of first metal layer 31 and second metal layer 32. Connector 70 connects wiring substrate 20 to external electric circuit (not illustrated). According to the present embodiment, connector 70 is a receptacle further including terminals each of which is connected to a corresponding one of third metal layer 33 and fourth metal layer 34, as illustrated in
Next, the functions and advantageous effects of semiconductor light-emitting device 10 according to the present embodiment will be described with reference to the above-described
As illustrated in
First metal layer 31 and second metal layer 32 extend from the inside of cap unit 50 toward the rearward of semiconductor light-emitting element 41 (i.e., in the direction opposite to the direction of propagation of emitted light L1) to the outside of cap unit 50. Accordingly, bonding surface 50b of cap unit 50 which is bonded to wiring substrate 20 intersects first metal layer 31 and second metal layer 32 in the top view of wiring substrate 20. Hereinafter, the side toward which emitted light L1 propagates with respect to semiconductor light-emitting element 41 is also referred to as forward, and the opposite direction of forward is also referred to as rearward. It should be noted that the portion of first metal layer 31 where first pad electrode 31p and pad electrode 31q are not provided is covered by second insulating layer 22. The portion of second metal layer 32 where second pad electrode 32p and pad electrode 32q are not provided is covered by second insulating layer 22.
In addition, as illustrated in
The first portion of spacer layer 30b is disposed at a position rearward from rear end surface 41R in the optical axis direction. The first portion of spacer layer 30b is disposed further from semiconductor light-emitting element 41 than first metal layer 31 is in the lateral direction. In other words, first metal layer 31 is disposed between the first portion of spacer layer 30b and semiconductor light-emitting element 41 in the lateral direction. In addition, first metal layer 31 is disposed between the first portion of spacer layer 30b and spacer layer 30a. The first portion of spacer layer 30b extends in the lateral direction.
The second portion of spacer layer 30b is disposed further from semiconductor light-emitting element 41 than first pad electrode 31p and first metal layer 31 are in the lateral direction. In other words, first pad electrode 31p and first metal layer 31 are disposed between the second portion of spacer layer 30b and semiconductor light-emitting element 41 in the lateral direction. The second portion of spacer layer 30b is connected to the first portion and extends in the optical axis direction.
The third portion of spacer layer 30b is disposed at a position forward from emission surface 41F. The third portion of spacer layer 30b is connected to the second portion and extends in the lateral direction.
The fourth portion of spacer layer 30b is disposed further from semiconductor light-emitting element 41 than second pad electrode 32p and second metal layer 32 are in the lateral direction. In other words, second pad electrode 32p and second metal layer 32 are disposed between the fourth portion of spacer layer 30b and semiconductor light-emitting element 41 in the lateral direction. The fourth portion of spacer layer 30b is connected to the third portion and extends in the optical axis direction.
The fifth portion of spacer layer 30b is disposed at a position rearward from rear end surface 41R in the optical axis direction. The fifth portion of spacer layer 30b is disposed further from semiconductor light-emitting element 41 than second metal layer 32 is in the lateral direction. In other words, second metal layer 32 is disposed between the fifth portion of spacer layer 30b and semiconductor light-emitting element 41 in the lateral direction. In addition, first metal layer 31 is disposed between the fifth portion of spacer layer 30b and spacer layer 30a. The fifth portion of spacer layer 30b is connected to the fourth portion and extends in the lateral direction.
The advantageous effects resulting from this configuration will be described with reference to
First metal layer 31 and second metal layer 32 according to the comparison example and the present embodiment have a large cross-sectional area such that a large amount of current can be supplied to semiconductor light-emitting element 41. For this reason, the thickness of first metal layer 31 and second metal layer 32 is approximately greater than or equal to 0.02 mm and less than or equal to 0.15 mm. Second insulating layer 22 above each of the metal layers as described above is formed by applying and curing a liquid insulating material on first metal layer 31 and second metal layer 32, and has a thickness approximately greater than or equal to 0.02 mm and less than or equal to 0.1 mm. Accordingly, the upper surface of second insulating layer 22 has an uneven shape along the upper surface of first insulating layer 21 and each of the metal layers, as illustrated in cross-sectional view (a) of
When a wiring substrate of the comparison example in which a spacer is not disposed as illustrated in
On the other hand, with wiring substrate 20 according to the present embodiment, as illustrated in cross-sectional view (a) of
In addition, according to the present embodiment, as illustrated in
According to the present embodiment, the thicknesses of spacer layers 30a and 30b are equal to the thicknesses of first metal layer 31 and second metal layer 32. In addition, first metal layer 31, second metal layer 32, and spacer layers 30a and 30b are covered by second insulating layer 22 with the same thickness. With this configuration, it is possible to further flatten upper surface 20a of wiring substrate 20. As a result, it is possible to further reduce the possibility of formation of a gap between bonding surface 50b and wiring substrate 20. Furthermore, by covering each of the metal layers and each of the spacer layers with second insulating layer 22, it is possible to reduce the possibility of disconnection of each of the metal layers due to contact with an external object.
In addition, the distance (i.e., gap) between first metal layer 31 and each of spacer layers 30a and 30b is smaller than the width of first metal layer 31 (i.e., the dimension of first metal layer 31 in the direction perpendicular to the extending direction and thickness direction). In addition, the distance between second metal layer 32 and each of spacer layers 30a and 30b is smaller than the width of second metal layer 32. With this configuration, it is possible to further reduce the dimension of the recess formed in upper surface 20a of wiring substrate 20. In addition, the distance between spacer layer 30a and each of first metal layer 31 and second metal layer 32 may be made smaller than the width of spacer layer 30a. Moreover, the distance between spacer layer 30b and each of first metal layer 31 and second metal layer 32 may be made smaller than the width of spacer layer 30b. With this configuration, it is possible to further reduce the dimensions of the recess formed in upper surface 20a of wiring substrate 20. As a result, it is possible to further reduce the possibility of formation of a gap between bonding surface 50b and wiring substrate 20. It should be noted that, the distance between first metal layer 31 and each of spacer layers 30a and 30b may be greater than the width of first metal layer 31. In addition, the distance between second metal layer 32 and each of spacer layers 30a and 30b may be greater than the width of second metal layer 32. With this configuration, when spacer layers 30a and 30b comprise metal, it is possible to inhibit short circuit between first metal layer 31 and second metal layer.
Next, a design example of each of the metal layers will be described with reference to
Electrical wiring comprising a metal layer has a slight (electrical) resistance. However, when power is supplied to semiconductor light-emitting element 41 that is high in optical output, even a slight resistance of the electrical wiring cannot be ignored because the amount of current that is supplied is large. For example, a current approximately greater than or equal to 1 ampere and less than or equal to 50 amperes, and a voltage approximately greater than or equal to 2 volts and less than or equal to 6 volts are applied to semiconductor light-emitting element 41 with a high optical output approximately greater than or equal to 1 watt and less than or equal to 100 watts. For example, when semiconductor light-emitting element 41 with an applied current of 2 amperes and an operating voltage of 2 volts is used, the voltage drop in the electrical wiring is 0.2 V, even when the wiring resistance is 0.1Ω. In other words, the operating voltage increases by 0.2V. For this reason, wiring resistance cannot be ignored as a factor that increases the operating voltage of semiconductor light-emitting device 10.
As illustrated in
The following describes in detail a method of reducing the resistance of electric wiring that comprise a metal layer as described above.
According to the conventional techniques, ceramic and a metal layer are integrally sintered to form electrical wiring, and thus the metal layer is formed using conductive paste that comprises, as a main component, tungsten which is a material suitable for integrated sintering. However, tungsten has a relatively large volume resistivity of approximately 5.7×10−8 Ω·m, which is likely to be a factor of an increase in wiring resistance.
According to the present embodiment, the metal layer comprises copper which has a relatively low volume resistivity of approximately 1.8×10−8 Ω·m, or a material including copper as the main component.
In addition, according to the conventional techniques, the metal layer is formed inside the ceramic, and thus it is necessary to increase the adhesion between the metal layer and the ceramic. As a result, it is necessary to reduce thickness T of the metal layer to be smaller than, for example, 50 μm. In addition, thickness T of the metal layer may be smaller than 20 μm, for example. With this configuration, it is possible to reduce the formation of unevenness on the surface of the ceramic layer. In such a case, a restriction is added to the design conditions of the metal layer to reduce the wiring resistance. For example, when tungsten is used as the material of the metal layer, as illustrated in
According to the present embodiment, as indicated in design example 4 of
It should be noted that, by using copper as the material of the metal layer, as indicated in design example 3, it is possible to reduce the wiring resistance to approximately one third of the wiring resistance of design example 1, even with the same thickness T and width W as those of design example 1.
In addition, when the amount of applied current is larger as indicated in design example 5 and design example 6 of
As indicated in design examples 4 to 6 of
According to the present embodiment, with spacer layers 30a and 30b, it is possible to narrow the width of the recess between each of the metal layers and a corresponding one of the spacer layers to be, for example, less than or equal to 0.3 mm. With this configuration, the gap between cap unit 50 and wiring substrate 20 can be filled with bonding material 55. As a result, it is possible to seal the gap between cap unit 50 and wiring substrate 20.
In addition, with wiring substrate 20 according to the present embodiment, it is not necessary to provide wiring in the substrate, and thus the configuration is simplified.
It should be noted that although the same material as each of the metal layers has been used as the material that each of the spacer layers comprises according to the present embodiment, the material that each of the spacer layers can comprise is not limited to this. For example, in the process illustrated in
Next, a method of manufacturing semiconductor light-emitting device 10 according to the present embodiment will be described. First, a manufacturing method of wiring substrate 20 will be described with reference to
First, as metal substrate 28, a flat plate of oxygen-free copper having a thickness of 2 mm, for example, is prepared as illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Then, as illustrated in
Next, the manufacturing method of cap unit 50 will be described with reference to
Side wall 51 and holder 52 are bonded by optical contact or laser bonding to form cap unit 50 having a box shape.
Thickness Ds of each of the side walls of holder 52 is, for example, approximately greater than or equal to 0.3 mm and less than or equal to 2 mm, which is greater than the thickness of side wall 51. For this reason, even when side wall 51 that is thinner than side walls 52a, 52b, and 52c is used, holder 52 that is structurally strong with side walls 52a, 52b, and 52c which are relatively thick holds side wall 51, and thus it is possible to inhibit side wall 51 from being damaged. In addition, side wall 51 and holder 52 comprise the same material, and thus it is possible to inhibit damage due to expansion and contraction caused by temperature.
Next, the method of attaching wiring substrate 20 to cap unit 50 according to the present embodiment will be described with reference to
According to the present embodiment, top plate 52d of cap unit 50 is transparent, and thus it is possible to adjust the position of cap unit 50 with high precision without contact between side wall 51 which is a light-transmissive window and the emission surface of semiconductor light-emitting element 41, as illustrated in
In addition, it is possible to reduce the distance between semiconductor light-emitting element 41 and the outside of cap unit 50, by using thin side wall 51.
In addition, wiring substrate 20 includes a spacer, and wiring substrate 20 and side wall 51 of cap unit 50 are bonded above the spacer. With this configuration, a small amount of bonding material is sufficient to bond the gap between wiring substrate 20 and side wall 51, and thus it is possible to inhibit an excess bonding material from reaching the vicinity of semiconductor light-emitting element 41 that is located in close proximity and changing the properties of emitted light L1.
By reducing the distance between semiconductor light-emitting element 41 and the outside of cap unit 50, for example, as illustrated in
At this time, the distance resulting from adding thickness Dg of side wall 51 and gap Dgap between side wall 51 and the emission surface should be short. By making gap Dgap smaller than thickness Dg of side wall 51, it is possible to bring lens optical element 92 close to the emission surface of semiconductor light-emitting element 41 while maintaining the strength of side wall 51.
According to the above-described configuration, semiconductor light-emitting device 10 according to the present embodiment is capable of causing semiconductor light-emitting element 41 to emit emitted light L1 with a large optical output, by applying a large amount of current to semiconductor light-emitting element 41 with a small wiring resistance. In addition, semiconductor light-emitting element 41 above wiring substrate 20 is sealed by cap unit 50, and thus it is possible to improve the reliability of semiconductor light-emitting element 41. Furthermore, the distance between light-emitting point 41e of semiconductor light-emitting element 41 and the outside of cap unit 50 is reduced. Accordingly, it is possible to more freely design external optical elements such as lens optical elements which are disposed outside 10 and are optically coupled to light-emitting point 41e. In addition, as illustrated in
Next, a semiconductor light-emitting device according to Variation 1 of the present embodiment will be described. The semiconductor light-emitting device according to the present variation differs from semiconductor light-emitting device 10 according to Embodiment 1 in the configuration of the spacer layer, and matches in the other configurations. The following describes the semiconductor light-emitting device according to the present variation with a focus on the difference from semiconductor light-emitting device 10 according to Embodiment 1, with reference to
The first portion of spacer layer 130b is disposed at a position rearward from rear end surface 41R. The first portion of spacer layer 130b is disposed further from semiconductor light-emitting element 41 than first metal layer 31 is in the lateral direction. In other words, first metal layer 31 is disposed between the first portion of spacer layer 130b and semiconductor light-emitting element 41. In addition, first metal layer 31 is disposed between the first portion of spacer layer 130b and spacer layer 130a. The first portion of spacer layer 130b extends in the lateral direction.
The second portion of spacer layer 130b is disposed further from semiconductor light-emitting element 41 than first pad electrode 31p and first metal layer 31 are in the lateral direction. In other words, first pad electrode 31p and first metal layer 31 are disposed between the second portion of spacer layer 130b and semiconductor light-emitting element 41 in the lateral direction. The second portion of spacer layer 130b is connected to the first portion and extends in the optical axis direction.
The third portion of spacer layer 130b is disposed at a position forward from emission surface 41F. The third portion of spacer layer 130b is connected to the second portion and extends in the lateral direction.
The fourth portion of spacer layer 130b is disposed further from semiconductor light-emitting element 41 than second pad electrode 32p and second metal layer 32 are in the lateral direction. In other words, second pad electrode 32p and second metal layer 32 are disposed between the fourth portion of spacer layer 130b and semiconductor light-emitting element 41 in the lateral direction. The fourth portion of spacer layer 130b is connected to the third portion and extends in the optical axis direction.
The fifth portion of spacer layer 130b is disposed at a position rearward from rear end surface 41R in the optical axis direction. The fifth portion of spacer layer 130b is disposed further from semiconductor light-emitting element 41 than second metal layer 32 is in the lateral direction. In other words, second metal layer 32 is disposed between the fifth portion of spacer layer 130b and semiconductor light-emitting element 41 in the lateral direction. In addition, second metal layer 32 is disposed between the fifth portion of spacer layer 130b and spacer layer 130a. The fifth portion of spacer layer 130b is connected to the fourth portion and extends in the lateral direction.
Such spacer layers 130a and 130b can be formed at the same time as second metal layer 32 in the process of forming each of the metal layers in the same manner as each of the spacer layers according to Embodiment 1. It should be noted that, also in the case where each of the spacer layers is in contact with second metal layer 32 as in the present variation, each of the spacer layers is disposed at a position different from the position at which second metal layer 32 is disposed.
With spacer layers 130a and 130b according to the present variation, the gap between second metal layer 32 and each of the spacer layers is zero, and thus a recess is not formed, above the upper surface of the wiring substrate, at the position corresponding to the gap between second metal layer 32 and each of the spacer layers. As a result, it is possible to reduce the formation of a gap between bonding surface 50b of cap unit 50 and the upper surface of the wiring substrate. In other words, it is possible to more securely seal bonding surface 50b of cap unit 50 and the upper surface of the wiring substrate.
Although each of the spacer layers has been connected to second metal layer 32 in the present variation, each of the spacer layers may be connected to first metal layer 31. In this case, spacer layers 130a and 130b may comprise the material that first metal layer 31 comprises. In other words, spacer layers 130a and 130b may comprise the material that one of first metal layer 31 or second metal layer 32 comprises, and be electrically connected to the one of first metal layer 31 or second metal layer 32.
Next, a semiconductor light-emitting device according to Variation 2 of the present embodiment will be described. The semiconductor light-emitting device according to the present variation differs from semiconductor light-emitting device 10 according to Embodiment 1 in the configuration of the spacer layer, and matches in the other configurations. The following describes the semiconductor light-emitting device according to the present variation with a focus on the difference from semiconductor light-emitting device 10 according to Embodiment 1, with reference to
With the wiring substrate according to the present variation, the gap between each of the metal layers and spacer layers 30a and 30b can be filled with spacer layers 30c, and thus it is possible to reduce the dimensions of the recess formed in the upper surface of the wiring substrate compared to wiring substrate 20 according to Embodiment 1. As a result, it is possible to reduce the formation of a gap between bonding surface 50b of cap unit 50 and the upper surface of the wiring substrate. In other words, it is possible to more securely seal bonding surface 50b of cap unit 50 and the upper surface of the wiring substrate.
In addition, the thickness of each of spacer layer 30c may be the same as each of the metal layers and spacer layers 30a and 30b. With this configuration, it is possible to further reduce the dimensions of the recess formed in the upper surface of the wiring substrate.
Next, a semiconductor light-emitting device according to Variation 3 of the present embodiment will be described. The semiconductor light-emitting device according to the present variation matches semiconductor light-emitting device 10 according to Embodiment 1 in points other than that a shielding component disposed between temperature sensing element 60 and semiconductor light-emitting element 41 is included. The following describes the semiconductor light-emitting device according to the present variation with a focus on the difference from semiconductor light-emitting device 10 according to Embodiment 1, with reference to
As illustrated in
Next, a semiconductor light-emitting device according to Embodiment 2 will be described. The semiconductor light-emitting device according to the present embodiment differs from semiconductor light-emitting device 10 according to Embodiment 1 mainly in the configurations of the first metal layer and the second metal layer. The following describes the semiconductor light-emitting device according to the present embodiment focusing on the differences from semiconductor light-emitting device 10 according to Embodiment 1.
First, the overall configuration of the semiconductor light-emitting device according to the present embodiment will be described with reference to
As illustrated in
Wiring substrate 220 according to the present embodiment includes metal substrate 228, first insulating layer 221, second insulating layer 222, third metal layer 233, fourth metal layer 234, and protection film 225, as illustrated in
According to the present embodiment, in the same manner as Embodiment 1, through-holes 228a and 228b and positioning holes 229a and 229b are provided in wiring substrate 220. Through-holes 228a and 228b and positioning holes 229a and 229b according to the present embodiment differ from through-holes 28a and 28b and positioning holes 29a and 29b according to Embodiment 1 in their arrangement in wiring substrate 220. According to the present embodiment, positioning holes 229a and 229b are located in proximity to the rear end portion of wiring substrate 220. Here, the rear end portion of wiring substrate 220 is an end portion out of the two end portions of wiring substrate 220 in the direction of propagation of emitted light L1, which is farther from light-emitting point 41e. Through-holes 228a and 228b are located in proximity to the center of wiring substrate 220 in the propagation direction of emitted light L1.
Metal substrate 228 differs from metal substrate 28 according to Embodiment 1 in their arrangement and a total number of the holes provided, and matches in the other points.
First insulating layer 221 is an insulating layer having a configuration equivalent to the configuration of first insulating layer 21 according to Embodiment 1, and opening 221a is formed therein.
First metal layer 231, second metal layer 232, third metal layer 233, and fourth metal layer 234 are metal layers spaced apart from each other above first insulation layer 221. According to the present embodiment, first metal layer 231 extends from first pad electrode 231p in the direction perpendicular to the propagation direction of emitted light L1 and parallel to the main surface of metal substrate 228, as illustrated in
Third metal layer 233 and fourth metal layer 234 are wiring connected to temperature sensing element 60, in the same manner as third metal layer 33 and fourth metal layer 34 according to Embodiment 1. According to the present embodiment, as illustrated in
First pad electrode 231p and second pad electrode 232p have configurations equivalent to the configurations of first pad electrode 31p and second pad electrode 32p according to Embodiment 1, respectively, as illustrated in
Spacer layers 230a, 230b, and 230c are layers that are disposed at positions different from the positions at which first metal layer 231 and second metal layer 232 above first insulating layer 221, as illustrated in
Spacer layer 230a has an L-shape in the top view of wiring substrate 220 and is composed of two portions. The first portion of spacer layer 230a is disposed at a position rearward from rear end surface 41R in the optical axis direction. The first portion of spacer layer 230a is disposed between semiconductor light-emitting element 41 and first extraction electrode 237 in the lateral direction. The first portion of spacer layer 230a extends in the optical axis direction. The second portion of spacer layer 230a is disposed at a position rearward from rear end surface 41R of semiconductor light-emitting element 41 in the optical axis direction. The second portion of spacer layer 230a is connected to the first portion and extends in the lateral direction.
Spacer layer 230b has an L-shape in the top view of wiring substrate 220 and is composed of two portions. The first portion of spacer layer 230b is disposed at a position rearward from rear end surface 41R in the optical axis direction. In addition, the first portion of spacer layer 230b is disposed between semiconductor light-emitting element 41 and second extraction electrode 238 in the lateral direction. The first portion of spacer layer 230b extends in the optical axis direction. The second portion of spacer layer 230b is disposed at a position rearward from rear end surface 41R in the optical axis direction. The second position of spacer layer 230b is disposed between the first portion of spacer layer 230b and spacer layer 230a. The second portion of spacer layer 230b is connected to the first portion and extends in the lateral direction.
Spacer layer 230c is composed of three portions. The first portion of spacer layer 230c is disposed between semiconductor light-emitting element 41 and first extraction electrode 237 in the lateral direction. The first portion of spacer layer 230c is disposed at a position forward from first metal layer 231 in the optical axis direction. The first portion of spacer layer 230c extends in the optical axis direction. The second portion of spacer layer 230c is disposed at a position forward from emission surface 41F. The second portion of spacer layer 230c is connected to the first portion and extends in the lateral direction. The third portion of spacer layer 230c is disposed between semiconductor light-emitting element 41 and second extraction electrode 238 in the lateral direction. The third portion of spacer layer 230c is disposed at a position forward from second metal layer 232 in the optical axis direction. The third portion of spacer layer 230c is connected to the second portion and extends in the optical axis direction.
Second insulating layer 222 is an insulating layer disposed above first insulating layer 221 as illustrated in
Protection film 225 is a metal film disposed, for example, at a position at which submount 45 is bonded in wiring substrate 220, as illustrated in
First extraction electrode 237 and second extraction electrode 238 are each an example of the extraction electrode, and are electrically connected to first metal layer 231 and second metal layer 232, respectively. According to the present embodiment, first extraction electrode 237 and second extraction electrode 238 are disposed above first metal layer 231 and second metal layer 232, respectively. First extraction electrode 237 and second extraction electrode 238 are disposed in proximity to first pad electrode 231p and second pad electrode 232p, respectively. With this configuration, the lengths of first metal layer 231 and second metal layer 232 can be reduced, and thus it is possible to reduce the resistance of first metal layer 231 and second metal layer 232.
First extraction electrode 237 and second extraction electrode 238 each have an annular shape, and include, in the center portion, electrode through-hole 237a and electrode through-hole 238a, respectively, which penetrate through wiring substrate 220. Through-holes 228a and 228b are holes for inserting a fixing component such as a screw when fixing wiring substrate 220 to closely adhere to a heat sink or the like. According to the present embodiment, electrode through-holes 237a and 238a are located on one side and the other side of wiring substrate 220, respectively, relative to the region in which semiconductor light-emitting element 41 is disposed. In other words, semiconductor light-emitting element 41 is disposed between electrode through-hole 237a and electrode through-hole 238a.
Bonding layer 255 is a component that bonds bonding surface 50b of cap unit 50 and upper surface 220a of wiring substrate 220. According to the present embodiment, bonding layer 255 includes first auxiliary bonding film 255a, bonding material 255b, and second auxiliary bonding film 255c. First auxiliary bonding film 255a and second auxiliary bonding film 255c are metal films disposed above bonding surface 50b and the upper surface of second insulating layer 222, respectively, and comprise Ni, Au, or the like. These auxiliary bonding films allow cap unit 50 and second insulating layer 222 to be easily bonded by bonding material 255b. Bonding material 255b is an alloy material that comprises AuSn solder, or the like.
Temperature sensing element 60 is an element equivalent to temperature sensing element 60 according to Embodiment 1. According to the present embodiment, temperature sensing element 60 is covered by cap unit 50 as illustrated in
As illustrated in
Connector 270 is a connecting component including terminals each of which is connected to a corresponding one of third metal layer 233 and fourth metal layer 234. According to the present embodiment, unlike connector 70 according to Embodiment 1, connector 270 does not have terminals that are connected to first metal layer 231 and second metal layer 232.
Next, the advantageous effects of semiconductor light-emitting device 210 according to the present embodiment will be described with reference to
First, as illustrated in
Then, cap unit 50 is disposed above upper surface 220a of wiring substrate 220. Wiring substrate 220 is then heated to melt bonding material 255b between first auxiliary bonding film 255a and second auxiliary bonding film 255c. Then, bonding material 255b is solidified by cooling wiring substrate 220. In this manner, it is possible to bond first auxiliary bonding film 255a and second auxiliary bonding film 255c by bonding material 255b, as illustrated in
Next, a light source device in which semiconductor light-emitting device 210 according to the present embodiment is used will be described with reference to
As illustrated in
Heat sink 219 is a heat-dissipating component comprising a material that is high in thermal conductivity, such as metal. Heat sink 219 comprises, for example, iron, iron alloy, aluminum, aluminum alloy, copper, or the like. In addition, aluminum alloy having a surface on which alumite treatment has been applied, or copper having a surface on which Ni plating has been applied may also be used. In heat sink 219, positioning pins P1 and P2 and threaded holes T1 to T4 are formed, as illustrated in
Semiconductor light-emitting device 210 is fixed to closely adhere to heat sink 219, using terminal fixing screws S1 and S2, and fixing screws S3 and S4. More specifically, fixing screws S3 and S4 penetrate through through-holes 228a and 228b, respectively, in the wiring substrate and are fixed to threaded holes T3 and T4, respectively, in heat sink 219.
Terminal fixing screw S1 penetrates through a hole formed in terminal 213 and electrode through-hole 237a in wiring substrate 220, and is fixed to threaded hole T1 in heat sink 219. Terminal fixing screw S1 penetrates through electrode through-hole 237a, and terminal 213 is disposed between terminal fixing screw S1 and first extraction electrode 237. With this configuration, first extraction electrode 237 and terminal 213 are electrically connected.
Terminal fixing screw S2 is fixed to threaded hole T2 in heat sink 219 through a hole formed in terminal 214 and electrode through-hole 238a in wiring substrate 220. Terminal fixing screw S2 penetrates through electrode through-hole 238a, and terminal 214 is disposed between terminal fixing screw S2 and second extraction electrode 238. With this configuration, second extraction electrode 238 and terminal 214 are electrically connected.
As described above, it is possible to fix semiconductor light-emitting device 210 to heat sink 219. In this manner, since semiconductor light-emitting device 210 can be firmly fixed to heat sink 219, using terminal fixing screws S1 and S2, as well as fixing screws S3 and S4, heat generated by the semiconductor light-emitting element 41 of semiconductor light-emitting device 210 can be effectively dissipated from metal substrate 228 to heat sink 219.
In addition, according to the above-described configuration, it is possible to electrically connect terminal 213 and terminal 214 to first extraction electrode 237 and second extraction electrode 238, respectively. As a result, it is possible to supply a large amount of current to semiconductor light-emitting device 210 via cables 211 and 212.
It should be noted that fixing screws S3 and S4 comprise a metal material, for example. On the other hand, for terminal fixing screws S1 and S2, screws that comprise an insulating material such as plastic, ceramic, etc. or that are coated with insulation are used to inhibit short circuits between each of the terminals and metal substrate 228 and between each of the terminals and heat sink.
Connector 271 is connected to connector 270. With this configuration, it is possible to obtain a signal from temperature sensing element 60 via cable 272.
Next, Variation 1 of the light source device according to the present embodiment will be described. The light source device according to the present variation has a configuration in which a terminal fixing screw or the like for fixing more firmly semiconductor light-emitting device 210 to heat sink 219, etc. is included. Hereinafter, the configuration of the terminal fixing screw, etc. of the light source device according to the present variation will be described with reference to
According to the present variation, heat sink 219 includes a surface that is conductive, and comprises, for example, an aluminum alloy without surface treatment. According to the present variation, terminal 213 and wiring substrate 220 are fixed to threaded hole T1, etc. of heat sink 219, using terminal fixing screw Sc1 or the like that comprises iron, stainless steel, or other conductive material. In this case, washer Wi (i.e., a spacer) having a ring shape and comprising an insulating material is inserted between terminal fixing screw Sc1 and terminal 213, as illustrated in
With this configuration, it is possible to more firmly fix semiconductor light-emitting device 210 and heat sink 219, as well as closely adhere semiconductor light-emitting device 210 and heat sink 219. As a result, it is possible to efficiently dissipate heat from semiconductor light-emitting element 41 of semiconductor light-emitting device 210 to heat sink 219.
Next, a semiconductor light-emitting device according to Embodiment 3 will be described. The semiconductor light-emitting device according to the present embodiment differs from semiconductor light-emitting device 210 according to Embodiment 2 mainly in the direction of extraction of emitted light. The following describes the semiconductor light-emitting device according to the present embodiment focusing on the differences from semiconductor light-emitting device 210 according to Embodiment 2, with reference to
As illustrated in
As illustrated in
As illustrated in
According to the above-described configuration, it is possible to easily extract emitted light L1 from semiconductor light-emitting element 41 from the upper surface of cap unit 350 to the outside.
Cap unit 350 is, for example, formed by bonding top plate 351 to holder 352 having a frame shape, by optical contact or laser bonding. As a result, top plate 351 and the peripheral portion of holder 352 are closely adhere to each other. In addition, holder 352 includes a surface facing top plate 351 and the first auxiliary bonding film (not illustrated) is disposed on the surface.
Spacer layers are each disposed between first insulating layer 221 and the bonding surface of cap unit 350 with upper surface 220a of wiring substrate 220, in semiconductor light-emitting device 310 according to the present embodiment as well. Second auxiliary bonding film 255c is disposed above each of the spacer layers. As a result of bonding holder 352 and wiring substrate 220 by bonding adhesive, it is possible to seal the gap between cap unit 350 and wiring substrate 220. With this configuration, the advantageous effects equivalent to those of semiconductor light-emitting device 210 according to Embodiment 2 are yielded by semiconductor light-emitting device 310 according to the present embodiment as well.
It should be noted that, as the configuration between cap unit 350 and wiring substrate 220, the configuration equivalent to that of Embodiment 1 may be employed.
It should be noted that, although semiconductor light-emitting device 310 including a single semiconductor light-emitting element 41 has been described as an example in the above-described embodiment, semiconductor light-emitting device 310 may include a plurality of semiconductor light-emitting elements 41 (see
In addition, although the reflective optical element including a reflective surface slanted at 45 degrees with respect to the optical axis has been disposed at a position facing the emission surface of semiconductor light-emitting element 41 according to the above-described embodiment, other optical element may be disposed. For example, a reflective optical element provided with a wavelength conversion member comprising a phosphor layer or the like disposed on a reflective mirror surface slanted at any angle greater than or equal to 10 degrees and less than or equal to 80 degrees with respect to the optical axis may be disposed. In this case, for example, a semiconductor laser element using a nitride semiconductor material with emitted light L1 having a peak wavelength in the wavelength range of approximately from greater than or equal to 380 nm to less than or equal to 490 nm may be used as semiconductor light-emitting element 41. With this configuration, a portion of emitted light L1 emitted from semiconductor light-emitting element 41 is wavelength-converted by the reflective optical element, thereby making it possible to emit light including the portion of emitted light L1 and the wavelength-converted light from top plate 351 of semiconductor light-emitting device 310. More specifically, emitted light L1 may be light having a wavelength in the blue region and the wavelength-converted light may be light having a wavelength in the yellow region. With this configuration, it is possible to implement a semiconductor light-emitting device which emits white light that is high in luminance and optical output from top plate 351, and is highly reliable.
In addition, as the reflective optical element, a diffractive optical element or diffuse optical element may be used. With this configuration, it is possible to emit emitted light L1 that has been emitted from semiconductor light-emitting element 41 from top plate 351 in a predetermined emission pattern in any direction by the reflective optical element. In this case, for example, by using emitted light L1 having a wavelength in the 900 nm band, it is possible to implement semiconductor light-emitting device 310 that emits infrared light that is high in optical output, and is highly reliable. Such semiconductor light-emitting device 310, for example, can be used for light detection and ranging (Lidar) device, etc.
Next, a semiconductor light-emitting device according to a variation of the present embodiment will be described. The semiconductor light-emitting device according to the present variation includes a plurality of semiconductor light-emitting elements. A reflective optical element is disposed at a position facing the emission surface of each of the plurality of semiconductor light-emitting elements 41. The plurality of semiconductor light-emitting elements 41 and reflective optical elements are arranged in a matrix. Hereinafter, the configuration of the semiconductor light-emitting device according to the present variation will be described with reference to
Semiconductor light-emitting device 310b according to the present variation includes wiring substrate 320b, a plurality of semiconductor light-emitting elements 41, a plurality of submounts 45, a cap unit (not illustrated in
Wiring substrate 320b includes a metal substrate (not illustrated in
Positioning holes 229a and 229b and through-holes 228a to 228d are formed in wiring substrate 320b.
First insulating layer 321 is disposed above the metal substrate, and includes opening 321a formed therein.
First metal layers 331a to 331c are disposed above first insulating layer 321, and connected to first pad electrode 331p and connector 371. Second metal layers 332a to 332c are disposed above first insulating layer 321, and connected to second pad electrode 332p and connector 372.
Third metal layer 333 is disposed above first insulating layer 321, and connected to temperature sensing element 60 and connector 371. Fourth metal layer 334 is disposed above first insulating layer 321, and connected to temperature sensing element 60 and connector 372.
Second insulating layer 322 is disposed above first insulating layer 321, and covers at least a portion of each of the first metal layers, each of the second metal layers, and each of the spacer layers.
Spacer layers 530a to 530i are disposed between the bonding surface of the cap unit and first insulating layer 321, at positions different from the positions of each of the first metal layers and each of the second metal layers. Each of the spacer layers is disposed along the bonding surface of the cap unit in the present variation as well.
According to the present variation, semiconductor light-emitting element 41 is mounted above submount 45. The three semiconductor light-emitting elements, which are aligned in the same row (i.e., arranged in the horizontal direction of
According to the above-described configuration, it is possible to increase the optical output of the emitted light emitted from semiconductor light-emitting device 310b compared to the case where a single semiconductor light-emitting element 41 is used. In addition, although the heat generated in semiconductor light-emitting device 410 increases with increase in the optical output, it is possible, with semiconductor light-emitting device 310b according to the present variation, to efficiently discharge the heat using a heat sink or the like. As a result, it is possible to inhibit degradation of each of the semiconductor light-emitting elements. It is thus possible to implement semiconductor light-emitting device 310b which is high in optical output and is highly reliable. Such semiconductor light-emitting device 310b as described above can be used, for example, as a light source for a projector by using, as semiconductor light-emitting element 41, a semiconductor laser element that emits emitted light having a wavelength in the visible light region such as blue, green, and red.
Next, a semiconductor light-emitting device according to Embodiment 4 will be described. The semiconductor light-emitting device according to the present embodiment differs from semiconductor light-emitting device 10 according to Embodiment 1 in that, for example, a plurality of semiconductor light-emitting elements are included. The following describes the semiconductor light-emitting device according to the present embodiment focusing on the differences from semiconductor light-emitting device 10 according to Embodiment 1, with reference to
Semiconductor light-emitting device 410 according to the present embodiment includes wiring substrate 420, cap unit 450, semiconductor light-emitting elements 441a to 441c, submount 445, temperature sensing element 60, shielding component 60s, and connector 70.
Cap unit 450, temperature sensing element 60, and connector 70 have configurations equivalent to the configurations of cap unit 50, temperature sensing element 60, and connector 70, according to Embodiment 1, respectively. It should be noted that cap unit 450 includes side wall 451 that is a light-transmissive window. In addition, shielding component 60s includes a configuration equivalent to the configuration of shielding component 60s according to Variation 3 of Embodiment 1. It should be noted that, according to the present embodiment, temperature sensing element 60 and shielding component 60s are disposed inside cap unit 450.
Wiring substrate 420 includes metal substrate 428, first insulating layer 421, second insulating layer 422, spacer layers 430a, 430b, 430c, and 430d, first metal layer 431, second metal layer 432, third metal layer 433, fourth metal layer 434, first pad electrode 431p, second pad electrode 432p, and a protection film (not illustrated in
According to the present embodiment, in the same manner as wiring substrate 20 according to Embodiment 1, through-holes 428a and 428b and positioning holes 429a and 429b are provided in wiring substrate 420.
Opening 421a is formed in first insulating layer 421 in the same manner as first insulating layer 21 according to Embodiment 1. A protection film comprising Ni, Au, or the like is formed in opening 421a to form a mounting surface for mounting each semiconductor light-emitting element. According to the present embodiment, semiconductor light-emitting elements 441a to 441c are disposed in the opening via submount 445.
First metal layer 431, second metal layer 432, third metal layer 433, fourth metal layer 434, first pad electrode 431p, and second pad electrode 432p have the same configurations as the configurations of first metal layer 431, second metal layer 432, third metal layer 433, fourth metal layer 434, first pad electrode 31p, and second pad electrode 32p according to Embodiment 1, respectively.
Spacer layers 430a, 430b, 430c, and 430d according to the present embodiment are disposed between first insulating layer of wiring substrate 420 and the bonding surface of cap unit 450 with wiring substrate 420, in the same manner as the spacer layers according to Embodiment 1. According to the present embodiment, the spacer layer is disposed at a position different from the position of each of the metal layers above first insulating layer. With this configuration, the advantageous effects equivalent to those of semiconductor light-emitting device 10 according to Embodiment 1 are yielded by semiconductor light-emitting device 410 according to the present embodiment as well.
Submount 445 includes an insulating block that is a rectangular parallelepiped block comprising an insulating material, first electrodes 447a to 447c and second electrode 448 each of which is a metal film disposed on the upper surface of the insulating block, and a metal film (not illustrated) disposed on the lower surface of the insulating block. First electrodes 447a to 447c and second electrode 448 are spaced apart from each other and electrically insulated. In addition, first electrodes 447a to 447c and second electrode 448 are electrically insulated from the metal film disposed on the lower surface of the insulating block. The metal films disposed on the lower surfaces of first electrodes 447a to 447c, second electrode 448, and the insulating block are metal films that comprise Ni, Cu, Pi, Au, or the like.
Each of semiconductor light-emitting elements 441a to 441c has a configuration equivalent to the configuration of semiconductor light-emitting element 41 according to Embodiment 1. According to the present embodiment, semiconductor light-emitting elements 441a to 441c are junction-down mounted to first electrodes 447a to 447c, respectively.
In addition, first pad electrode 431p and first electrode 447a are connected to each other via metal wire W2. The upper surface of semiconductor light-emitting element 441a and first electrode 447b are connected to each other via metal wire W1. The upper surface of semiconductor light-emitting element 441b and first electrode 447c are connected to each other via metal wire W1. The upper surface of semiconductor light-emitting element 441c and second electrode 448 are connected to each other via metal wire W1. Second electrode 448 and second pad electrode 432p are connected to each other via metal wire W3. With this configuration, semiconductor light-emitting elements 441a to 441c can be connected in series. As a result, it is possible to supply the same current to each of the semiconductor light-emitting elements.
According to the above-described configuration, it is possible to increase the optical output of the emitted light emitted from semiconductor light-emitting device 410 compared to the case where a single semiconductor light-emitting element 41 is used. In addition, although the heat generated in semiconductor light-emitting device 410 increases with increase in the optical output, it is possible, with semiconductor light-emitting device 410 according to the present embodiment, to efficiently discharge the heat using a heat sink or the like. As a result, it is possible to inhibit degradation of each of the semiconductor light-emitting elements.
Although the semiconductor light-emitting device, etc. according to the present disclosure have been described based on the embodiments thus far, the present disclosure is not limited to the embodiments described above.
For example, in each of the above-described embodiments, an example in which the semiconductor light-emitting element is a semiconductor light-emitting element has been described, but the semiconductor light-emitting element is not limited to the semiconductor light-emitting element. For example, the semiconductor light-emitting element may be a superluminescent diode or a quantum cascade laser.
In addition, in each of the above-described embodiments, an example in which a metal substrate is used as the first substrate has been described, but the first substrate may be an insulating substrate. In this case, the wiring substrate need not include the first insulating layer.
In addition, in each of the above-described embodiments, a temperature sensing element has been used as an example of the functional element, but some other functional element may be used. As other functional element, it is possible to use, for example, a light-receiving element, a switching element such as a transistor, and various passive elements such as a capacitor, an inductor, and a resistor. In addition, the shape of the metal layer or pad electrode to be connected to the functional element can be arbitrarily selected according to the type, etc. of the functional element. In addition, the semiconductor light-emitting element and the functional element may be electrically connected above the wiring substrate.
In addition, although the semiconductor light-emitting device according to Variation 2 of the above-described Embodiment 2 includes shielding component 60s, cap unit 50 may function as a shielding component when temperature sensing element 60 is disposed outside cap unit 50. In other words, it is possible to cause cap unit 50 to function as a shielding component, by reducing the transmittance of light from semiconductor light-emitting element 41 at the side wall facing rear end surface 41R of semiconductor light-emitting element 41 among the four side walls of cap unit 50.
In addition, in each of the above-described embodiments, the semiconductor light-emitting element has been mounted on the metal substrate via the submount, but the semiconductor light-emitting element may be directly mounted without involving the submount. In this case, the semiconductor light-emitting element may be junction-up mounted above the metal substrate.
It should be noted that, in each of the above-described embodiments, a semiconductor light-emitting device that includes a cap unit has been described, but it is possible to implement a semiconductor light-emitting device that does not include a cap unit as well. The following describes such a semiconductor light-emitting device with reference to
Semiconductor light-emitting device 910 includes wiring substrate 920, semiconductor light-emitting element 41, submount 45, temperature sensing element 60, and connector 70. Semiconductor light-emitting element 41, submount 45, temperature sensing element 60, and connector 70 according to the reference example include configurations equivalent to the configurations of semiconductor light-emitting element 41, submount 45, temperature sensing element 60, and connector 70 according to Embodiment 1.
Wiring substrate 920 matches wiring substrate 20 according to Embodiment 1 in the configuration other than the configuration of first insulating layer 921, the configurations of third metal layer 933 and fourth metal layer 934, and the point that a spacer layer is not provided. Opening 921a of first insulating layer 921 extends to the end edge of wiring substrate 920. In other words, opening 921a has an open shape in first insulating layer 921, which is open on the side-surface side in the emission direction of emitted light L1 of semiconductor light-emitting element 41. Third metal layer 933 and fourth metal layer 934 have configurations equivalent to the configurations of third metal layer 233 and fourth metal layer 234 according to Embodiment 2, respectively. In addition, second insulating layer 922 has a configuration equivalent to the configuration of second insulating layer 222 according to Embodiment 2.
It is possible to implement a semiconductor light-emitting device which is high in optical output, with semiconductor light-emitting device 910 having the configuration not provided with a cap unit as descried above as well. Furthermore, since semiconductor light-emitting device 910 does not include a cap unit or a spacer layer, semiconductor light-emitting device 910 has a configuration more simplified than the configuration of semiconductor light-emitting device 10 according to Embodiment 1, and also is higher in the degree of freedom of design.
In addition, forms obtained by various modifications to the respective exemplary embodiments described above that can be conceived by a person of skill in the art as well as forms realized by arbitrarily combining structural components and functions in the respective exemplary embodiments described above which are within the scope of the essence of the present disclosure are also included in the present disclosure.
Although only some exemplary embodiments of the present disclosure have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications are intended to be included within the scope of the present disclosure.
The semiconductor light-emitting device, etc. according to the present disclosure are applicable as, for example, a light source which is high in optical output and reliability, a laser processing machine, a vehicle lighting device such as a vehicle head light, a lighting device, a distance measuring devices such as a light detection and ranging (Lidar) device, a light source device for a projector, a medical light source device, a light source device for inspection, a light source device for sterilization, etc.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-141924 | Aug 2020 | JP | national |
This is a continuation application of PCT International Application No. PCT/JP2021/029884 filed on Aug. 16, 2021, designating the United States of America, which is based on and claims priority of Japanese Patent Application No. 2020-141924 filed on Aug. 25, 2020. The entire disclosures of the above-identified applications, including the specifications, drawings and claims are incorporated herein by reference in their entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2021/029884 | Aug 2021 | US |
| Child | 18172120 | US |
