Light-emitting device

Abstract

To provide a light emitting device capable of emitting light from a plurality of light emitting elements with different polarization directions from each other by aligning their polarization directions.SOLUTION: A light emitting device has a base having a bottom, a first semiconductor laser element located at the bottom of the base, a second semiconductor laser element located at the bottom of the base with a different polarization direction from that of the first semiconductor laser element, a lens member into which light emitted from the first and second semiconductor laser elements enters, and a wavelength plate arranged on the lens member to change the polarization direction of the first semiconductor laser element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Light-emitting devices incorporating multiple light-emitting elements such as LEDs and lasers have been known for some time. Furthermore, optical systems incorporating multiple light-emitting elements are often used in various light source devices, such as projectors, liquid crystal displays, and headlights. When designing such optical systems, one or more conditions related to optical characteristics are defined.

[0003] For example, Patent Document 1 discloses a laser light source provided in a display device, in which the polarization directions of a red laser light source, a blue laser light source, and a green laser light source are aligned. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2017-90799 Summary of the Invention [Problem to be solved by the invention]

[0005] However, Patent Document 1 does not disclose a solution for a light emitting device in which a plurality of light emitting elements with different polarization directions are arranged. [Means for solving the problem]

[0006] A light emitting device according to one embodiment of the present disclosure includes a base having a bottom, a first semiconductor laser element disposed at the bottom of the base, a second semiconductor laser element disposed at the bottom of the base and having a polarization direction different from that of the first semiconductor laser element, a lens member onto which light emitted from the first semiconductor laser element and the second semiconductor laser element is incident, and a wavelength plate disposed on the lens member and changing the polarization direction of the first semiconductor laser element. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a light emitting device that outputs light from a plurality of light emitting elements having different polarization directions with the same polarization direction. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of the light emitting device according to the first embodiment. [Figure 2] FIG. 2 is a top view of the light emitting device according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the light emitting device according to the first embodiment taken along a line connecting III-III in FIG. [Figure 4] FIG. 4 is a cross-sectional view of the light emitting device according to the first embodiment taken along a line connecting IV-IV in FIG. [Figure 5] FIG. 5 is a cross-sectional view of the light emitting device according to the first embodiment taken along a line connecting V and V in FIG. [Figure 6] FIG. 6 is a perspective view of the light emitting device according to the first embodiment, with part of the configuration removed, viewed from the same direction as in FIG. [Figure 7] FIG. 7 is a top view of the light emitting device according to the first embodiment, corresponding to FIG. [Figure 8] FIG. 8 is a schematic diagram showing main portions of light emitted from the first semiconductor laser element and the second semiconductor laser element of the light emitting device according to the first embodiment. [Figure 9] FIG. 9 is a perspective view of the light emitting device according to the second embodiment. [Figure 10] FIG. 10 is a top view of the light emitting device according to the second embodiment. [Figure 11] FIG. 11 is a cross-sectional view of the light emitting device according to the first embodiment taken along the line connecting XI-XI in FIG. [Figure 12] FIG. 12 is a perspective view of the light emitting device according to the second embodiment, with part of the configuration removed, viewed from the same direction as in FIG. [Figure 13]FIG. 13 is a perspective view of the light emitting device according to the third embodiment. [Figure 14] FIG. 14 is a top view of the light emitting device according to the third embodiment. [Figure 15] FIG. 15 is a cross-sectional view of the light emitting device according to the second embodiment taken along a line connecting XV-XV in FIG. [Figure 16] FIG. 16 is a perspective view of the light emitting device according to the third embodiment, with part of the configuration removed, viewed from the same direction as in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Modes for carrying out the present invention will be described below with reference to the drawings. However, the modes described below are intended to embody the technical concept of the present invention and are not intended to limit the present invention. Furthermore, in the following description, the same names and symbols indicate the same or similar components, and detailed description will be omitted as appropriate. Note that the size and positional relationship of components shown in each drawing may be exaggerated for clarity of explanation.

[0010] First Embodiment 1 to 7 are diagrams illustrating the structure of a light-emitting device 1 according to a first embodiment. FIG. 1 is a perspective view of the light-emitting device 1 as viewed from the light-emitting side. FIG. 2 is a top view of the light-emitting device 1 shown in FIG. 1, with the light-emitting side facing upward. FIG. 3 is a cross-sectional view of the light-emitting device 1 taken along a line connecting III-III in FIG. 2. FIG. 4 is a cross-sectional view of the light-emitting device 1 taken along a line connecting IV-IV in FIG. 2. FIG. 5 is a cross-sectional view of the light-emitting device 1 taken along a line connecting V-V in FIG. 2. FIG. 6 is a perspective view of the light-emitting device 1, with part of the configuration removed to visualize the space in which the semiconductor laser element is disposed, as viewed from the same direction as FIG. 1. FIG. 7 is a top view of the light-emitting device 1 shown in FIG. 6, with the light-emitting side facing upward. Note that FIG. 7 illustrates the light-emitting device 1 including wires, while the wires are omitted from the other figures to avoid clutter.

[0011] The components that make up the light emitting device 1 include a base 10, one first semiconductor laser element 20, two second semiconductor laser elements 30, a submount 40, a first light reflecting member 50, a second light reflecting member 60, a cover member 70, a lens member 80, an adhesive portion 90, a wire 91, and a wave plate 100.

[0012] Next, each component will be described. The base 10 has a bottom portion that forms the bottom surface of the base 10, and a frame portion that forms the side surface of the base 10. The frame portion also has an inner surface IS, and the inner surface IS and the upper surface US of the bottom form a recessed structure in the base 10 with a central recess (see Figures 6 and 7). A step portion ST is provided on part of the inner surface of the frame portion. The step portion ST may also be provided over the entire inner surface. A metal film is provided on the upper surface of the step portion.

[0013] The base 10 can be formed primarily from ceramic. However, it is not limited to ceramic, and it may also be formed from metal. Examples of the primary material of the base 10 include ceramics such as aluminum nitride, silicon nitride, aluminum oxide, and silicon carbide, metals such as copper, aluminum, and iron, and composites such as copper molybdenum, copper-diamond composites, and copper tungsten. Alternatively, the bottom and frame may be formed as separate members made of different primary materials, and the base 10 may be formed by joining the bottom and frame. For example, different metals may be used as the primary materials for the bottom and frame, or a bottom made primarily from metal and a frame made primarily from ceramic may be used.

[0014] The first semiconductor laser element 20 and the second semiconductor laser element 30 emit laser light. The laser light emitted from these semiconductor laser elements has a divergence, and forms an elliptical far-field pattern (hereinafter referred to as "FFP") in a plane parallel to the light-emitting end face. The FFP is specified by the light intensity distribution of the light in a plane that is some distance away from the light-emitting end face and parallel to the light-emitting end face. The shape of the FFP is determined by the 1 / e 2The light that forms the shape of the FFP is called the main part of the light.

[0015] 8 is a schematic diagram showing the main portions of light emitted from the first semiconductor laser element 20 and the second semiconductor laser element 30 of the light-emitting device 1. Note that only a portion of the light-emitting device 1 necessary for explanation is shown. As shown in FIG. 8, the shape of the FFP is an ellipse whose length in the stacking direction of multiple semiconductor layers including the active layer is longer than its length in the direction perpendicular to that. In this specification, the spread of light in the direction corresponding to the major axis of this ellipse is referred to as the vertical spread, and the spread of light in the direction corresponding to the minor axis is referred to as the horizontal spread.

[0016] Furthermore, in the space where the main portion of light is emitted, half the angle formed by the light traveling from the light-emitting end face along both ends of the major axis of the ellipse is referred to as the vertical divergence angle of the light, and half the angle formed by the light traveling from the light-emitting end face along both ends of the minor axis of the ellipse is referred to as the horizontal divergence angle of the light. Based on Figure 8, the vertical divergence angle of the first and second semiconductor laser elements is θ1 / 2, and the horizontal divergence angle is θ2 / 2. It can be said that the vertical divergence angle of the light emitted from the first and second semiconductor laser elements 20 and 30 is larger than the horizontal divergence angle.

[0017] The light emitted from the first semiconductor laser element 20 has a larger divergence angle in the vertical direction than the light emitted from the second semiconductor laser element 30. Although it depends on the divergence angle of the semiconductor laser element used, in order to effectively apply the light emitting device 1 of the first embodiment, it is preferable that the condition be satisfied between the first semiconductor laser element 20 and the second semiconductor laser element 30, that the divergence angle of the laser light emitted from the first semiconductor laser element 20 be larger by 10 degrees or more. The difference in the divergence angle of the laser light of the first semiconductor laser element 20 and the second semiconductor laser element 30 in the vertical direction can be, for example, 30 degrees or less.

[0018] For example, a semiconductor laser element that emits red light is used as the first semiconductor laser element 20, and a semiconductor laser element that emits blue light and a semiconductor laser element that emits green light are used as the second semiconductor laser element 30. Note that instead of using semiconductor laser elements of three colors, the color combinations may be changed.

[0019] The red light preferably has an emission peak wavelength in the range of 605 nm to 750 nm, and more preferably in the range of 610 nm to 700 nm. Examples of semiconductor laser elements that emit red light include those containing InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductors. Compared to semiconductor laser elements containing nitride semiconductors, semiconductor laser elements containing these semiconductors are more susceptible to output degradation due to heat. Taking this into consideration, it is preferable to provide two or more waveguide regions. Increasing the number of waveguide regions can dissipate heat and reduce output degradation of the semiconductor laser element.

[0020] The blue light preferably has an emission peak wavelength in the range of 420 nm to 494 nm, more preferably in the range of 440 nm to 475 nm. Examples of semiconductor laser elements that emit blue light include semiconductor laser elements containing nitride semiconductors. Examples of nitride semiconductors that can be used include GaN, InGaN, and AlGaN.

[0021] The green light preferably has an emission peak wavelength in the range of 495 nm to 570 nm, more preferably in the range of 510 nm to 550 nm. Examples of semiconductor laser elements that emit green light include semiconductor laser elements containing nitride semiconductors. Examples of nitride semiconductors that can be used include GaN, InGaN, and AlGaN.

[0022] Furthermore, the polarization directions differ by 90 degrees between the first semiconductor laser element 20 and the second semiconductor laser element 30. For example, the first semiconductor laser element 20 emits p-polarized laser light and the second semiconductor laser element 30 emits s-polarized laser light from their respective emission end faces.

[0023] The submount 40 is configured in a rectangular parallelepiped shape. However, the shape is not limited to a rectangular parallelepiped. The submount 40 can be formed using, for example, silicon nitride, aluminum nitride, or silicon carbide. However, other materials can also be used. Furthermore, a metal film is provided on a portion of the submount 40.

[0024] The first and second light reflecting members 50 and 60 have a bottom surface, a side surface extending perpendicularly from the bottom surface, and a top surface intersecting the side surface on the opposite side of the bottom surface. A portion of the top surface is not parallel to the bottom surface. Also, a portion of the top surface is parallel to the bottom surface. A light reflecting surface that reflects light is formed at least in the region that is not parallel to the bottom surface. The light reflecting surface of the first light reflecting member 50 and the light reflecting surface of the second light reflecting member 60 have different shapes. The light reflecting surface of the first light reflecting member 50 has a concave curved shape, while the light reflecting surface of the second light reflecting member 60 is flat. The angle between the flat light reflecting surface of the second light reflecting member 60 and the bottom surface is designed to be 45 degrees.

[0025] The first and second light reflecting members 50 and 60 can be formed by using a heat-resistant material as the main material to form their outer shapes, and a material with high light reflectivity for the surface of the formed outer shape where the light reflecting surface is desired. Examples of the main material include glass such as quartz or BK7 (borosilicate glass), metal such as aluminum, or silicon. Examples of the light reflecting surface include metals such as Ag and Al, and dielectric multilayer films such as Ta2O5 / SiO2, TiO2 / SiO2, and Nb2O5 / SiO2. The first and second light reflecting members 50 and 60 can be formed using a material with high light reflectivity, such as metal, and the light reflecting film may be omitted. The light reflecting surfaces of the first and second light reflecting members 50 and 60 can each have a light reflectivity of 99% or more for the peak wavelength of the laser light to be reflected. These light reflectivities can be 100% or less.

[0026] The lid member 70 is configured in the shape of a rectangular parallelepiped. The lid member 70 is translucent as a whole. It may have a non-translucent region in part. The shape is not limited to a rectangular parallelepiped. The lid member 70 may be formed using sapphire as the main material. A metal film is provided in part of the material. Sapphire is a material that has a relatively high refractive index and is also relatively strong. In addition to sapphire, other materials such as glass may also be used as the main material.

[0027] The lens member 80 has three lens portions 82 each having a lens shape and the remaining non-lens portion 81. The lens member 80 is formed such that the three lens portions 82 are connected to one surface of the non-lens portion 81. The lens member 80 can be formed such that the non-lens portion 81 and the lens portion 82 are integrated. For example, by molding using a mold having such a shape, it is possible to manufacture a lens member 80 in which the non-lens portion 81 and the lens portion 82 are integrated. Manufacturing an integrated lens member 80 is advantageous in terms of productivity.

[0028] Alternatively, a member having the shape of non-lens portion 81 and a member having the shape of lens portion 82 may be prepared separately, and lens portion 82 may be bonded to the surface of non-lens portion 81. Lens member 80 may be made of glass such as BK7, B270, or borosilicate glass, for example.

[0029] In addition, a plane of the non-lens portion 81 that overlaps with the surface on which the lens portion 82 is provided is defined as the boundary surface of the lens portion 82 or the non-lens portion 81. The boundary surface of the lens portion 82 refers to the surface of the lens portion 82 that overlaps with this boundary surface. Even if the lens portion 82 and the non-lens portion 81 are integrally formed, the virtual area that overlaps with the boundary surface can be considered as this. Furthermore, if the lens member 80 does not have a non-lens portion 81, the plane on the opposite side of the surface of the lens portion 82 that has the lens shape (curved structure) is considered to be the boundary surface of the lens portion 82.

[0030] The non-lens portion 81 is configured with a concave shape. Three lens portions 82 are provided in the concave depression of the non-lens portion 81. The height of the three lens portions 82 provided in the concave depression from the boundary surface is equal to the height from the boundary surface to the top surface of the concave shape. Here, "equal" includes a difference of up to 0.1 mm. Note that the difference in the height of the lens portions 82 less than the height to the top surface of the concave shape may be 0.1 mm or more. In other words, the height of the three lens portions 82 from the boundary surface is designed to be equal to or smaller than the height from the boundary surface to the top surface of the concave shape. Note that the height can be adjusted by increasing the thickness of the adhesive portion 90, making the height of the lens portions 82 greater than the height to the top surface of the concave shape.

[0031] The adhesive 90 is formed by hardening the adhesive. It is preferable to use an ultraviolet-curable resin as the adhesive that forms the adhesive 90. The ultraviolet-curable resin can be hardened in a relatively short time without heating, making it easy to fix the lens member 80 in the desired position.

[0032] The wave plate 100 may be a half-wave plate that changes the polarization direction of light by 90 degrees. The wave plate 100 is formed in the shape of a flat plate. The wave plate 100 has a rectangular shape when viewed from above. The shape does not have to be rectangular, but may be, for example, an elliptical shape, with one side longer than the other.

[0033] Next, a light emitting device 1 manufactured using these components will be described. A first semiconductor laser element 20 and two second semiconductor laser elements 30 are arranged via a submount 40 on an upper surface US of the bottom portion that forms the bottom surface of the base 10. When the submount 40 is not used, the first and second semiconductor laser elements are arranged directly on the upper surface US of the bottom portion. In the light emitting device 1, a red first semiconductor laser element 20, a blue second semiconductor laser element 30, and a green second semiconductor laser element 30 are arranged.

[0034] In the light emitting device 1, the first semiconductor laser element 20 emitting red light and the second semiconductor laser element 30 emitting blue light are arranged in the center, with the first semiconductor laser element 20 emitting red light and the second semiconductor laser element 30 emitting green light arranged on either side. This is because the first semiconductor laser element 20 emitting red light has poorer optical output characteristics relative to heat than the others. Furthermore, it is also because the second semiconductor laser element 30 emitting blue light generates less heat than the second semiconductor laser element 30 emitting green light. In other words, taking these heat characteristics into consideration, it is best to arrange the one of the three semiconductor laser elements with the best characteristics in the middle.

[0035] Furthermore, one first light reflecting member 50 and one second light reflecting member 60 are arranged on the upper surface US of the bottom portion. The upper surface US of the bottom portion is joined to the bottom surfaces of the first and second light reflecting members. The first and second light reflecting members are arranged so that a major portion of the light emitted from the first semiconductor laser element 20 is irradiated onto the light reflecting surface of the first light reflecting member 50, and a major portion of the light emitted from the second semiconductor laser element 30 is irradiated onto the light reflecting surface of the second light reflecting member 60.

[0036] By using reflection by the light reflecting member, the optical path length can be made longer compared to when no light reflecting member is used. A longer optical path length can reduce the influence of misalignment between the light reflecting member and the semiconductor laser element. Note that instead of using one second light reflecting member 60 for two second semiconductor laser elements 30, two second light reflecting members 60 may be provided, one for each of the two second semiconductor laser elements 30.

[0037] The frame of the base 10 surrounds the first and second semiconductor laser elements 20 and 30, the submount 40, and the first and second light reflecting members 50 and 60, which are arranged on the upper surface US of the bottom. Therefore, these components are arranged inside the frame formed by the frame and on the upper surface US of the bottom. One ends of multiple wires 91 are bonded to a metal film provided on the upper surface of the step portion ST of the frame. The other ends of the multiple wires 91 are bonded to the first and second semiconductor laser elements. This electrically connects the first and second semiconductor laser elements 20 and 30 to a power source provided outside the light emitting device 1.

[0038] A step portion ST is not provided in a portion of the inner surface IS of the frame portion of the base 10. This portion is also arranged so as to be located on the side surface of the first semiconductor laser element 20 opposite to the side surface closer to the first light reflecting member 50, and on the side surface of the first light reflecting member 50 opposite to the side surface closer to the first semiconductor laser element 20. If a step portion ST were provided on the side surface opposite to the side closer to the first semiconductor laser element 20, stretching a wire 91 connected to the first semiconductor laser element 20 would result in the wire straddling the first light reflecting member 50. Therefore, a step portion ST for electrical connection is not provided in this portion. By not providing a step portion ST in this portion, the light emitting device 1 can be made smaller.

[0039] The submount 40 has three semiconductor laser elements disposed on its upper surface. Alternatively, a submount 40 may be provided in one-to-one correspondence with each of the first and second semiconductor laser elements 20 and 30. The submount 40 is bonded at its bottom surface to the bottom of the base 10 and at its top surface to the semiconductor laser elements. The semiconductor laser elements are bonded to a metal film provided on the upper surface of the submount 40 via a conductive bonding agent such as Au—Sn.

[0040] From the viewpoint of heat dissipation, if the submount 40 has a higher thermal conductivity than the bottom of the base 10, it will be more effective as a heat spreader. For example, if a material containing a nitride semiconductor is used for the semiconductor laser element and aluminum nitride is used as the main material for the base 10, aluminum nitride or silicon carbide can be used for the submount 40. Note that if aluminum nitride is used for the base 10 and the submount 40, the aluminum nitride used for the submount 40 can have a higher thermal conductivity than the aluminum nitride used for the base 10.

[0041] The shape of the submount 40 is designed so that the heights from the bottom of the semiconductor laser elements 20 and 30 are the same. Furthermore, the distance between the submount 40 provided on the first semiconductor laser element 20 and the first light reflecting member 50 is designed to be the same as the distance between the submount 40 provided on the second semiconductor laser element 30 and the second light reflecting member 60. Even if the designs are the same, errors will occur due to material tolerances and mounting tolerances at the mounting stage. When referring to the height, length, or placement position of the light emitting device 1 as being the same, such errors are considered to be within the allowable range. Furthermore, these heights and distances do not necessarily have to be the same.

[0042] The distance between the emitting end face of the first semiconductor laser element 20 and the first light reflecting member 50 is designed to be the same as the distance between the emitting end face of the second semiconductor laser element 30 and the second light reflecting member 60. The emitting end faces of the first and second semiconductor laser elements are designed to be provided on the same plane. In other words, the emitting end faces of the first and second semiconductor laser elements are designed to be arranged on one of two imaginary parallel planes, and the side face of the first light reflecting member 50 closest to the first semiconductor laser element 20 and the side face of the second light reflecting member 60 closest to the second semiconductor laser element 30 are designed to be arranged on the other plane.

[0043] The lid member 70 is joined to the frame on the upper surface opposite the bottom surface of the base 10, and covers the frame formed by the inner surface IS of the frame. A metal film is provided on the underside of the lid member 70 in the area to be joined to the base 10, and the lid member 70 is fixed to the base 10 via Au—Sn or the like. When the frame is covered with the rectangular lid member 70, the height from the bottom surface of the base 10 to the upper surface of the frame is greater than the height from the bottom surface to the first and second semiconductor laser elements 20 and 30, and is also greater than the height to the first and second light reflecting members 50 and 60.

[0044] Furthermore, the closed space formed by joining the base 10 and the lid member 70 is a hermetically sealed space. By hermetically sealing in this manner, it is possible to prevent organic matter and the like from collecting on the light-emitting end faces of the first and second semiconductor laser elements.

[0045] The light reflected by the light reflecting surfaces of the first and second light reflecting members 50 and 60 enters the lid member 70. The lid member 70 is designed so that the region from where the reflected light enters to where it exits is translucent, so that at least the main portion of the reflected light passes through the lid member 70 and exits the upper surface. Here, translucency means that the light transmittance is 80% or higher. In other words, the main portion of the light reflected by the light reflecting surfaces passes through the lid member 70, which is translucent in the wavelength range of the light emitted by the first and second semiconductor laser elements 20 and 30, and exits the hermetically sealed space.

[0046] In the region through which light passes, the higher the refractive index of the material forming the lid member 70, the more the light can be suppressed from spreading. For example, the lid member 70 may be made of sapphire at least in the region through which the light reflected by the light reflecting surface of the first or second light reflecting member, out of the main portion of the light emitted from the first and second semiconductor laser elements, passes.

[0047] The adhesive portion 90 is formed on the upper surface of the lid member 70 in an area where the lid member 70 and the lens member 80 are bonded together. The adhesive portion 90 is formed between the lid member 70 and the lens member 80 by applying an adhesive to the bonding area on the upper surface of the lid member 70, attaching the underside of the lens member 80 thereto, and then curing the adhesive. The adhesive portion 90 is also formed to have a certain thickness so that the lid member 70 and the lens member 80 do not come into contact with each other. This thickness is designed taking into consideration mounting errors and component tolerances. As a result, if a deviation occurs in the position of light passing through the lid member 70 due to mounting errors of the semiconductor laser element and the light reflecting member arranged on the base 10, the lens member 80 can be bonded to the lid member 70 after adjusting the position and height of the lens member 80.

[0048] Furthermore, the adhesive portion 90 is not formed over the entire upper surface of the lid member 70 or the entire lower surface of the lens member 80, but is provided so as not to interfere with the path of the light emitted from the first and second semiconductor laser elements 20 and 30. Therefore, preferably, the adhesive portion 90 is not formed on the lower surface of the lens member 80 corresponding to the region where the lens portion 82 of the lens member 80 is formed, but is formed in the region of the outer edge of the lens member 80.

[0049] The lens member 80 is bonded to the lid member 70 via an adhesive part 90 on top of the lid member 70. The lens member 80 is also arranged so that the three lens portions 82 are located closer to the top surface of the lid member 70. Therefore, the top surfaces (lens surfaces) of the three lens portions 82 face downward relative to the lens member arranged above the base.

[0050] Additionally, the concave top surface of lens member 80 and the upper surface of cover member 70 are joined via an adhesive to form adhesive portion 90. When the concave shape of non-lens portion 81 is viewed as the upper surface of lens member 80 and the flat surface on the opposite side is viewed as the lower surface, lens member 80 is turned upside down and disposed so that the flat surface on the lower surface is on the upper surface of the light-emitting device.

[0051] As described above, the three lens portions 82 are designed not to extend beyond the upper surface of the concave surface of the non-lens portion 81 in order to avoid contact with the cover member 70. If they were designed to come into contact with the cover member 70, it would be difficult to adjust the position and height when joining the lens member 80 to the cover member 70.

[0052] The three lens portions 82 of the lens member 80 are arranged corresponding to the three semiconductor laser elements arranged at the bottom, respectively. That is, the upper surfaces (lens surfaces) of the three lens portions 82 become the incident surfaces for the light emitted from the three semiconductor laser elements and incident on the lens member 80.

[0053] A major portion of the light emitted from the first semiconductor laser element 20 is reflected by the light reflecting surface of the first light reflecting member 50, passes through the cover member 70 and enters the lens member 80, passes through the first lens portion 83, which is one of the three lens portions 82, and exits the lens member 80.

[0054] A major portion of the light emitted from one of the two second semiconductor laser elements 30 is reflected by the light reflecting surface of the second light reflecting member 60, passes through the cover member 70 and enters the lens member 80, passes through the second lens portion 84, which is one of the three lens portions 82 and is different from the first lens portion 83, and exits the lens member 80.

[0055] A major portion of the light emitted from the other of the two second semiconductor laser elements 30 is reflected by the light reflecting surface of the second light reflecting member 60, passes through the cover member 70 and enters the lens member 80, passes through the third lens portion 85, which is the remaining one of the three lens portions 82, and exits the lens member 80.

[0056] In this way, the lens portion 82 is formed so that one lens portion 82 corresponds to one semiconductor laser element. Therefore, the number of lens portions 82 formed can vary depending on the number of semiconductor laser elements mounted in the light emitting device 1. For example, in a light emitting device 1 in which only one semiconductor laser element is arranged, only one lens portion 82 may be formed in the lens member 80. In other words, the lens portion 82 may be made up of one or more lens portions 82.

[0057] The lens shape of each lens portion 82 is designed so that light from the corresponding semiconductor laser element is collimated and emitted. In the light emitting device 1, the first to third lens portions 83 to 85 have different lens shapes, which means that multiple lens portions 82 with the same lens shape can be formed. Note that the lens shape may be such that it controls the traveling direction of light for purposes other than collimation, such as focusing.

[0058] Furthermore, in the case where the non-lens portion 81 and each of the first to third lens portions are prepared separately in the lens member 80, the non-lens portion 81 may be bonded onto the cover member 70 using an adhesive, and then each lens portion 82 may be disposed and bonded to the upper surface of the non-lens portion 81. In this case, the first and second semiconductor laser elements emit light, and the position and direction of the light emitted from the non-lens portion 81 are measured, and the position of the lens portion 82 can be determined based on the measurement results.

[0059] Wave plate 100 is disposed to change the polarization direction of light emitted from first semiconductor laser element 20. For this reason, wave plate 100 is disposed on the surface of lens member 80 opposite to the concave surface on which first lens portion 83 is disposed, in a region through which light emitted from first semiconductor laser element 20 and incident on first lens portion 83 passes.

[0060] The wave plate 100 has its bottom surface bonded to the surface of the lens member 80 opposite to the concave surface on which the first lens portion 83 is disposed. Therefore, in the light emitting device 1, the wave plate 100 is disposed above the lens member 80. Furthermore, when viewed from above, the longitudinal direction of the wave plate 100 is closer to the longitudinal direction of the first lens portion 83 than the lateral direction of the first lens portion 83. In the light emitting device 1, the wave plate 100 is disposed with its longitudinal direction aligned with the longitudinal direction of the first lens portion 83.

[0061] Moreover, wave plate 100 is provided at a position that covers first lens portion 83 when viewed from above. Moreover, wave plate 100 is provided at a position and in an area that covers first lens portion 83 when viewed from above, but does not cover lens portions other than first lens portion 83. Specifically, in light emitting device 1, wave plate 100 is not provided at a position that covers second lens portion 84 and third lens portion 85 when viewed from above.

[0062] In other words, no wave plate is provided on the optical path of light from a semiconductor laser element that serves as a reference for aligning the polarization direction, but a wave plate is provided on the optical path of light from a semiconductor laser element that does not match the polarization direction that serves as the reference, in order to align it with the reference.

[0063] The length of the wave plate 100 in the longitudinal direction, as viewed from above, is equal to or greater than the length of the first lens portion 83 in the longitudinal direction. Preferably, the length is also equal to or less than the length of the lens member 80 in the same direction as the longitudinal direction of the first lens portion 83. This allows the wave plate 100 to be positioned without protruding from the lens member 80. If the wave plate 100 protrudes, there is a risk that the wave plate 100 will get caught on the protruding portion and become detached.

[0064] In top view, the length of the wave plate 100 in the short-side direction is the same as or greater than the length of the first lens portion 83 in the short-side direction. Preferably, the length of the wave plate 100 is in the same direction as the short-side direction of the first lens portion 83 and does not exceed the outer surface of the lens member 80 at the end of the direction from the second lens portion 84 to the first lens portion 83. This allows the wave plate 100 to be disposed without protruding from the lens member 80.

[0065] More preferably, it extends in the same direction as the short-side direction of first lens portion 83 and does not extend beyond the inner surface forming the concave shape of lens member 80, which is located at the end of the direction from second lens portion 84 toward first lens portion 83. This makes it possible to control the polarization direction of light without making wave plate 100 too large.

[0066] The wave plate 100 is bonded to the lens member 80. For example, a light-transmitting resin adhesive can be used for bonding. Note that a non-light-transmitting adhesive can also be used, but in this case, it is desirable to provide the adhesive in areas other than the light-transmitting area so as not to impede the passage of light. By using a resin adhesive, the stress between the wave plate 100 and the lens member 80 can be alleviated, and separation of the wave plate 100 can be prevented.

[0067] The polarization directions of the first semiconductor laser element 20 and the second semiconductor laser element 30 differ by 90 degrees. For example, the first semiconductor laser element 20 emits p-polarized laser light, and the second semiconductor laser element 30 emits s-polarized laser light from their respective emission end faces. Therefore, by passing the light emitted from the first semiconductor laser element 20 through the wave plate 100, the polarization directions of the light emitted from the first and second semiconductor laser elements 20 and 30 and then emitted from the light emitting device 1 can be aligned. Therefore, the wave plate 100 may be any type that eliminates deviation in the polarization direction.

[0068] In this way, by providing the wave plate 100 on the surface opposite to the surface on which the lens portion 82 of the lens member 80 is provided, it is possible to realize a light emitting device that emits light with a uniform polarization direction with a compact design. Furthermore, according to the configuration of the light emitting device 1, collimated light is incident on the wave plate 100, so that reflection loss on the surface of the wave plate 100 can be reduced compared to when diffused or concentrated light is incident.

[0069] Next, how the propagation of light emitted from the semiconductor laser element is controlled in the light emitting device 1 configured as above will be described (see FIGS. 4 and 5).

[0070] Here, with respect to the first and second semiconductor laser elements 20 and 30, the light emitted from each semiconductor laser element at a position closest to the light-emitting end face of the semiconductor laser element is referred to as the bottom light. The light emitted from each semiconductor laser element at a position farthest from the light-emitting end face of the semiconductor laser element is referred to as the top light. The light emitted from each semiconductor laser element that travels perpendicular to the light-emitting end face of the semiconductor laser element, i.e., the light that travels along the optical axis, is referred to as the central light.

[0071] In Figure 8, the position on the light reflecting surface of the first light reflecting member 50 where the central light emitted from the first semiconductor laser element 20 is irradiated is shown as CP1, and the position on the light reflecting surface of the second light reflecting member 60 where the central light emitted from the second semiconductor laser element 30 is irradiated is shown as CP2.

[0072] In the light emitting device 1, the light emitted from the first and second semiconductor laser elements is reflected by the light reflecting surface of the first or second light reflecting member, and enters the lid member 70 from the hermetically sealed space. The light that passes through the lid member 70 and exits passes through the gap between the lid member 70 and the lens member 80 created by the adhesive portion 90, and enters the lens member 80. The light that enters the lens member 80 then passes through the lens portion 82 and is emitted to the outside of the light emitting device 1. As for the light emitted from the first semiconductor laser element 20, the light that is emitted from the lens member 80 passes through the wave plate 100 and is emitted to the outside of the light emitting device 1.

[0073] The light reflecting surface of the first light reflecting member 50 narrows the vertical spread of the light emitted from the first semiconductor laser element 20. In other words, the light is reflected so that the spread angle of the reflected light is smaller than the spread angle of the light emitted from the first semiconductor laser element 20 and irradiated onto the light reflecting surface in the vertical direction of the light.

[0074] Furthermore, the light reflecting surface of first light reflecting member 50 narrows the vertical spread of light emitted from first semiconductor laser element 20, but does not collimate the light. Furthermore, as shown in Fig. 5, in light emitting device 1, the light reflecting surface of first light reflecting member 50 is designed so that the reflected light has some spread.

[0075] The expression "light has a spread" refers to a relationship in which, for light emitted from a semiconductor laser element and passing through two points at different positions with the same optical path length, the longer the optical path length, the greater the distance between the two points at the same optical path length. Therefore, in light emitting device 1, this relationship is satisfied at least from the time the light is reflected by the light reflecting surface until it enters cover member 70. For example, when light emitted from a focal point is reflected by a hyperbolic reflecting surface, the reflected light has a spread.

[0076] If the design is such that the reflected light is collimated, the light incident on the lens member 80 is already collimated, eliminating the need for the first lens portion 83. In this case, if the mounting positions of the first semiconductor laser element 20 or the first light reflecting member 50 deviate from the design values, the effects of the deviation cannot be corrected by adjusting the mounting position or height of the lens member 80. On the other hand, by designing the shape of the light reflecting surface of the first light reflecting member 50 so that the light spreads while suppressing the spread of light due to reflection, it becomes possible to adjust the emitted light by the first lens portion 83 provided on the lens member 80.

[0077] The shape of the light reflecting surface of the first light reflecting member 50 may be a shape that narrows the reflected light instead of widening it. "Light narrows" refers to a relationship in which, for light passing through two points at different positions with the same optical path length, the longer the optical path length, the smaller the distance between the two points at the same optical path length. For example, when light emitted from a focal point is reflected by an ellipsoidal reflecting surface, the reflected light narrows. When light emitted from a focal point is reflected by a parabolic reflecting surface, the reflected light is collimated.

[0078] Furthermore, the distance from the emitting end face of the first semiconductor laser element 20 to a position CP1 on the light reflecting surface of the first light reflecting member 50 where the central light of the first semiconductor laser element 20 is irradiated is longer than the distance from the emitting end face of the second semiconductor laser element 30 to a position CP2 on the light reflecting surface of the second light reflecting member 60 where the central light of the second semiconductor laser element 30 is irradiated. In other words, the central light of the first semiconductor laser element 20 is reflected at a farther position.

[0079] The light reflecting surface of the first light reflecting member 50 is designed to reflect the central ray of the light emitted from the first semiconductor laser element 20 in a direction at an acute angle to the optical axis, rather than in a direction perpendicular to the optical axis. On the other hand, the light reflecting surface of the second light reflecting member 60 is designed to reflect the central ray of the light emitted from the second semiconductor laser element 30 in a perpendicular direction.

[0080] The first to third lens portions are connected so that they have the same lens width LW in the direction corresponding to the major axis of the light at the boundary surfaces of the lens portions 82, and so that the centers of the lens widths LW are also the same. In this way, collimated light of the same width can be emitted from each lens portion 82 in the direction corresponding to the major axis of the light at the boundary surfaces of the lens portions 82. In addition, the emission positions of the collimated light in the direction corresponding to the major axis of the light at the boundary surfaces of the lens portions 82 can be aligned.

[0081] Specifically, the shape of the light reflecting surface is designed so that, in the direction corresponding to the major axis of the light at the boundary surface of the lens portion 82, the distance between the emission point of the central light of the first semiconductor laser element 20 emitting from the lens portion 82 and the emission point of the central light of the second semiconductor laser element 30 is smaller than the distance between the irradiation point of the central light of the first semiconductor laser element 20 and the irradiation point of the central light of the second semiconductor laser element 30 on the light reflecting surface.

[0082] As described above, the light emitting device 1 according to the first embodiment can provide a light emitting device that outputs light from the first semiconductor laser element and the second semiconductor laser element, which are light emitting elements having different polarization directions, with the polarization directions aligned.

[0083] Second Embodiment Next, a light emitting device 2 according to a second embodiment will be described. Similar to the light emitting device 1 of the first embodiment, the light emitting device 2 includes a base, one first semiconductor laser element, two second semiconductor laser elements, two light reflecting members, a submount, a lid member, a lens member, an adhesive portion, wires, and a wave plate as its components. However, the light emitting device 2 differs from the light emitting device 1 of the first embodiment in the orientation of the lens member, the shape of the wave plate, the bonding mode between the lens member and the wave plate, and the shape of the light reflecting surface of the first light reflecting member.

[0084] Fig. 9 is a perspective view of the light emitting device 2 as viewed from the light emitting side. Fig. 10 is a top view of the light emitting device 2 shown in Fig. 9, with the light emitting side facing upward. Fig. 11 is a cross-sectional view of the light emitting device 2 taken along the line XI-XI in Fig. 10. Fig. 12 is a perspective view of the light emitting device 2, with part of the configuration removed to visualize the space in which the semiconductor laser element is disposed, as viewed from the same direction as Fig. 9.

[0085] In the light emitting device 2, the lens member 80 is arranged so that the lens portions 82 of the lens member 80 are provided on the surface opposite to the surface that is bonded to the cover member 70. In other words, the lens member 80 is arranged so that the three lens portions 82 are on the side opposite to the side closer to the top surface of the cover member 70. Furthermore, with respect to the lens member 80 that is arranged above the base 10, the top surfaces (lens surfaces) of the three lens portions 82 face upward.

[0086] Furthermore, lens member 80 is bonded to lid member 70 via adhesive portion 90 on top of lid member 70. That is, the lower surface of lens member 80 and the upper surface of lid member 70 are bonded via the adhesive to form adhesive portion 90. As a result, light emitted from the first and second semiconductor laser elements enters non-lens portion 81 of lens member 80 and exits from lens portion 82 of lens member 80.

[0087] In the light emitting device 2, when the concave shape of the non-lens portion 81 is on the upper surface side of the lens member 80 and the flat surface on the opposite side is viewed as the lower surface side, the lens member 80 is arranged so that the upper surface side of the lens member 80 is on the upper surface side of the light emitting device 2, without having to be turned upside down as in the light emitting device 1.

[0088] The three lens portions 82 of the lens member 80 are arranged corresponding to the three semiconductor laser elements arranged on the bottom of the base 10. In other words, the upper surfaces (lens surfaces) of the three lens portions 82 become emission surfaces for the light emitted from the three semiconductor laser elements and incident on the lens member 80.

[0089] Wave plate 200 is disposed to change the polarization direction of light emitted from first semiconductor laser element 20. Wave plate 200 is also disposed on lens member 80. Wave plate 200 is also disposed on the surface of lens member 80 on which the concave shape is formed (concave surface).

[0090] Moreover, the wave plate 200 is disposed above the first lens portion 83 of the lens member 80 in a region through which the light emitted from the first semiconductor laser element 20 and emitted from the first lens portion 83 passes. As a result, the light emitted from the first semiconductor laser element 20, incident on the non-lens portion 81 of the lens member 80, and emitted from the first lens portion 83 of the lens member 80 is incident on the wave plate 200.

[0091] In the light emitting device 2, the wave plate 200 is bonded to the concave upper surface of the non-lens portion 81. More specifically, the wave plate 200 is bonded to the concave uppermost surface of the lens member 80. In order to avoid contact between the wave plate 200 and the first lens portion 83, it is preferable to design the wave plate 200 so that at least the distance (height) from the bonding surface of the lens member 80 with the lid member 90 to the first lens portion 83 does not exceed the distance (height) from the bonding surface of the lens member 80 with the lid member 90 to the bonding surface of the concave non-lens portion 81 with the wave plate 200.

[0092] Wave plate 200 is bonded to the concave upper surface of non-lens portion 81, and is therefore formed in a shape that ensures an area for bonding to non-lens portion 81. Wave plate 200 in light emitting device 2 has a bonding area that bonds to the concave upper surface of non-lens portion 81, and a non-bonding area that extends from this bonding area toward first lens portion 83.

[0093] According to such a joining mode, there is no need to worry about the adhesive used for joining entering the light passage area between the lens member 80 and the wave plate 200, and therefore mounting can be easily performed.

[0094] Furthermore, it is preferable that the non-bonded region does not come into contact with the first lens portion 83. If the non-bonded region comes into contact with the first lens portion 83, the tolerances required when forming the lens shape of the first lens portion 83 will affect the mounting accuracy of the wave plate 200. Light emitted from the first lens portion 83 of the lens member 80 is incident on the non-bonded region of the wave plate 200 and passes through it. From the perspective of miniaturizing the light emitting device, it is preferable that the wave plate 200 fits within the outline of the lens member 80 when viewed from above.

[0095] Furthermore, the bonded region of the wave plate 200 is the same as or larger than the non-bonded region. To make the bond stronger, it is preferable to design the wave plate 200 and the lens member 80 so that the bonded region is larger. That is, when viewed from above, the outer shape of the bonded surface of the lens member 80 is larger than the outer shape of the first lens portion 83. Note that the bonded region may be smaller than the non-bonded region, but if the bonded region is too small, the bond will be unstable.

[0096] The bonding surface of non-lens portion 81 in the concave shape with wave plate 200 is provided on the side of first lens portion 83, along the direction in which the first to third lens portions are aligned (the coupling direction). When viewed from above, the bonding surface of non-lens portion 81 is provided so that first lens portion 83 is sandwiched between the bonding surface of non-lens portion 81 and second lens portion 84.

[0097] Furthermore, in the light emitting device 2, the shape of the light reflecting surface of the first light reflecting member 250 is flat rather than curved. Furthermore, the first light reflecting member 250 has a flat light reflecting surface, similar to the second light reflecting member 60. By changing from a curved surface to a flat surface, the position CP1 where the central light of the first semiconductor laser element 20 is irradiated becomes closer to the position CP2 where the central light of the second semiconductor laser element 30 is irradiated.

[0098] As in the first embodiment, the angle formed between the flat surface, which is the light reflecting surface of first light reflecting member 250, and the bottom surface may be determined so that light is collimated more efficiently at the point where it is collimated by lens member 80. Therefore, the angle may be different from or the same as the angle in second light reflecting member 60.

[0099] Third Embodiment Next, a light emitting device 3 according to a third embodiment will be described. Similar to the light emitting device 2 of the second embodiment, the light emitting device 3 has a base, one first semiconductor laser element, two second semiconductor laser elements, a submount, a light reflecting member, a cover member, a lens member, an adhesive portion, wires, and a wave plate as its components. However, the shape of the lens member, the shape of the wave plate, the bonding mode between the lens member and the wave plate, and the number of light reflecting members are different from those of the light emitting device 2 of the second embodiment.

[0100] Fig. 13 is a perspective view of the light emitting device 3 as seen from the side from which light is emitted. Fig. 14 is a top view of the light emitting device 3 shown in Fig. 13, with the side from which light is emitted as the upper surface. Fig. 15 is a cross-sectional view of the light emitting device 3 taken along the line XV-XV in Fig. 14. Fig. 16 is a perspective view of the light emitting device 3, as seen from the same direction as Fig. 13, with part of the configuration removed to visualize the space in which the semiconductor laser element is arranged.

[0101] In the light emitting device 3, the concave shape in the non-lens portion 381 of the lens member 380 is formed so as to surround the lens portion 382. Furthermore, the concave shapes are provided on both sides of the first lens portion 383 along the non-connecting direction, not along the direction in which the first to third lens portions are lined up (connecting direction). The non-connecting direction is the direction in which one lens portion 382 is not connected to other lens portions 382. In other words, a straight line drawn in the connecting direction intersects only one lens portion 382.

[0102] In the light emitting device 3, the wave plate 300 is bonded to portions of the concave upper surface that are provided on both sides of the first lens portion 383 along the non-connecting direction. When viewed from above, the bonding surfaces of the non-lens portions 381 are provided so that the first lens portion 383 is sandwiched between the bonding surfaces of the non-lens portions 381. On the other hand, the wave plate 300 is not bonded to portions of the concave upper surface that are provided along the connecting direction. Note that the bonding may include the portions that are provided along the connecting direction.

[0103] Wave plate 300 also has a first bonding region that is a bonding region that is bonded to the concave upper surface of non-lens portion 381 on one side, a non-bonding region that extends from this bonding region toward first lens portion 383, and a second bonding region that is a bonding region that is bonded to the concave upper surface of non-lens portion 381 on the other side from this non-bonding region.

[0104] According to this joining mode, the wave plate 300 is joined in two regions across the first lens portion 383, and therefore the wave plate 300 can be fixed more stably.

[0105] Furthermore, in the light emitting device 3, a single light reflecting member (first light reflecting member 350) forms a light reflecting surface that reflects light from the first and second semiconductor laser elements. The light reflecting surface has a flat shape. However, the light reflecting surface may also have a curved shape. By using a single first light reflecting member, the optical path length to position CP1 where the central light of the first semiconductor laser element 20 is irradiated becomes the same as the optical path length to position CP2 where the central light of the second semiconductor laser element 30 is irradiated.

[0106] As explained above, the light emitting device according to the present invention having the technical features disclosed in the specification is not limited to the structures of light emitting device 1, light emitting device 2, and light emitting device 3 described in each embodiment of the specification. For example, the present invention can be applied to a light emitting device having components not disclosed in any of the embodiments, and differences from the disclosed light emitting devices are not grounds for saying that the present invention cannot be applied.

[0107] Furthermore, even if a light-emitting device has a modified configuration by incorporating or replacing part of the configuration disclosed in another embodiment, it goes without saying that the modification is essentially a disclosure of the present invention if it is within the scope of ordinary design matters for a person skilled in the art.

[0108] This means that the present invention can be applied even if it is not essential to have all the necessary and sufficient components of the light-emitting device disclosed in any of the embodiments. For example, if some components of the light-emitting device disclosed in each embodiment are not recited in the claims, the invention described in the claims is claimed to be applicable, with the freedom of design by those skilled in the art, such as substitution, omission, modification of shape, and change of material, not limited to those disclosed in the present embodiment. [Industrial Applicability]

[0109] The light emitting device according to each embodiment can be used as a light source for head-mounted displays, projectors, vehicle headlights, lighting, display backlights, and the like. [Explanation of symbols]

[0110] 1, 2, 3 Light-emitting device 10 base 20 First semiconductor laser element 30 Second semiconductor laser element 40 Submount 50, 250, 350 First light reflecting member 60 Second light reflecting member 70 Lid member 80, 380 lens components 81, 381 non-lens part 82, 382 Lens section 83, 383 First lens part 84, 384 Second lens section 85, 385 Third lens section 90 Adhesive part 91 Wire 100, 200, 300 wave plates

Claims

1. a base having a bottom; a frame portion having two first inner side surfaces facing each other in a first direction with the bottom portion interposed therebetween, two second inner side surfaces facing each other in a second direction with the bottom portion interposed therebetween, a first step portion provided along one of the two second inner side surfaces, a second step portion provided along the other second inner side surface, a plurality of first metal films provided on the first step portions, and a plurality of second metal films provided on the second step portions; one or more first semiconductor laser elements that emit light traveling in the first direction from an emission end surface toward the first inner surface; a plurality of second semiconductor laser elements that emit light traveling in the first direction from an emission end surface toward the first inner surface; one or more light reflecting members that reflect light emitted from the second semiconductor laser elements between the light emitting end faces of the second semiconductor laser elements and the first inner surface; a plurality of wires, each of which is bonded to either one of the plurality of first metal films or the plurality of second metal films, for electrically connecting the one or more first semiconductor laser elements and the plurality of second semiconductor laser elements to the base; and the plurality of second semiconductor laser elements include second semiconductor laser elements arranged at positions sandwiched between the first semiconductor laser element and another second semiconductor laser, Among the plurality of wires, wires for electrically connecting the second semiconductor laser element disposed at the sandwiching position to the base portion include a first wire bonded to the first metal film and a second wire bonded to the second metal film; A light emitting device, wherein one or both of the two first inner surfaces is not provided with a step portion.

2. The light emitting device according to claim 1 , wherein the first inner side surface located in the first direction from the light emitting end surfaces of the second semiconductor laser elements does not have a step portion.

3. 3. The light emitting device according to claim 1, wherein no step is provided on the first inner side surface located in a direction opposite to the first direction from the light emitting end surfaces of the second semiconductor laser elements.

4. 4. The light emitting device according to claim 1, wherein wires for electrically connecting the second semiconductor laser elements arranged at the sandwiching position to the base are not joined to the first metal film and the second metal film on the first direction side from the light emitting end faces of the plurality of second semiconductor laser elements.

5. 5. The light emitting device according to claim 1, wherein a wire for electrically connecting the second semiconductor laser element arranged in the sandwiching position to the base does not overlap with the one or more light reflecting members when viewed from above.

6. The light emitting device comprises: Further comprising a submount having a metal film on an upper surface thereof; The second semiconductor laser element disposed at the sandwiching position is attached to the metal film of the submount. are placed, 6. A light emitting device according to claim 1, wherein one of the first wire and the second wire is bonded to a second semiconductor laser element arranged in the sandwiching position, and the other is bonded to the metal film of the submount.

7. the one or more first semiconductor laser elements emit red light, The light emitting device according to claim 1 , wherein the plurality of second semiconductor laser elements emit blue light or green light.

8. The light emitting device according to claim 1 , wherein the second semiconductor laser element disposed at the sandwiching position emits blue light.

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