Light emitting device and backlight

Abstract

To provide a light-emitting device capable of suppressing output reduction due to heat of a semiconductor laser element.SOLUTION: The light emitting device includes a substrate having an upper surface, first to third semiconductor laser elements provided on the upper surface and configured to emit first to third laser beams, respectively, and first to third reflective members provided on the upper surface and each including a reflective surface inclined with respect to the upper surface of the substrate and facing obliquely upward, a back surface located opposite to the reflective surface, and two lateral surfaces located between the reflective surface and the back surface. One of the two lateral surfaces of the second reflective member faces at least a portion of one of the two lateral surfaces of the third reflective member, and the reflective surfaces of the first to third reflective members reflect the first to third laser beams, respectively.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present disclosure relates to a light emitting device and a backlight. [Background technology]

[0002] Light-emitting devices including multiple semiconductor laser elements can be used in devices such as head-mounted displays, projectors, displays, and lighting fixtures. In such light-emitting devices, it is sometimes necessary to suppress the decrease in output power due to heat from the semiconductor laser elements. Examples of light-emitting devices include Patent Documents 1 and 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-161062 [Patent Document 2] Patent No. 6361293 Summary of the Invention [Problem to be solved by the invention]

[0004] There is a demand for a light emitting device that can suppress a decrease in output power due to heat from a semiconductor laser element. [Means for solving the problem]

[0005] In one embodiment, the light emitting device of the present disclosure includes: a substrate having an upper surface; a first semiconductor laser element, a second semiconductor laser element, and a third semiconductor laser element provided directly or indirectly on the upper surface and emitting a first laser beam, a second laser beam, and a third laser beam, respectively; and a first reflecting member, a second reflecting member, and a third semiconductor laser element provided directly or indirectly on the upper surface, each including a reflecting surface inclined with respect to the upper surface of the substrate and facing obliquely upward, a back surface located opposite to the reflecting surface, and two side surfaces located between the reflecting surface and the back surface. a first reflecting member, and a third reflecting member, wherein the back surface of the first reflecting member faces at least a portion of the back surface of the second reflecting member and at least a portion of the back surface of the third reflecting member, one of the two side surfaces of the second reflecting member faces at least a portion of one of the two side surfaces of the third reflecting member, the reflecting surface of the first reflecting member reflects the first laser light, the reflecting surface of the second reflecting member reflects the second laser light, and the reflecting surface of the third reflecting member reflects the third laser light. [Effects of the Invention]

[0006] A light emitting device can be realized that can suppress a decrease in output power due to heat from the semiconductor laser element. [Brief explanation of the drawings]

[0007] [Figure 1A] FIG. 1A is an exploded perspective view schematically illustrating the configuration of a light emitting device according to a first exemplary embodiment of the present disclosure. [Figure 1B] FIG. 1B is a top view of the light emitting device shown in FIG. 1A. [Figure 2A] FIG. 2A is a cross-sectional view parallel to the XZ plane, which schematically shows how laser light is emitted from the light emitting device of FIG. 1A. [Figure 2B] FIG. 2B is a cross-sectional view parallel to the YZ plane, which schematically shows how laser light is emitted from the light emitting device of FIG. 1A. [Figure 3A] FIG. 3A is a top view schematically showing a first example of the arrangement of three reflecting members. [Figure 3B]FIG. 3B is a top view schematically showing a second example of the arrangement of three reflecting members. [Figure 4] FIG. 4 is a top view schematically showing the configuration of a light emitting device according to a reference example. [Figure 5] FIG. 5 is a perspective view schematically illustrating the configuration of a white backlight according to an exemplary embodiment of the present disclosure. [Figure 6A] FIG. 6A is a cross-sectional view parallel to the YZ plane, which schematically shows how three color laser beams emitted from the light emitting device according to this embodiment enter a light guide plate. [Figure 6B] FIG. 6B is a cross-sectional view parallel to the YZ plane, which schematically shows how three color laser beams emitted from the light emitting device according to the reference example are incident on the light guide plate. [Figure 7A] FIG. 7A is a diagram showing the results of calculation of the intensity distribution in the light guide plate of three-color laser light emitted from a light emitting device according to a calculation example. [Figure 7B] FIG. 7B is a diagram showing the results of calculating the intensity distribution in the light guide plate of three-color laser light emitted from the light emitting device according to the reference example. [Figure 8A] FIG. 8A is a cross-sectional view parallel to the XZ plane, which schematically shows how laser light is emitted from a light-emitting device according to a modified example of this embodiment. [Figure 8B] FIG. 8B is a cross-sectional view parallel to the YZ plane, which schematically shows how laser light is emitted from a light-emitting device according to a modified example of this embodiment. [Figure 9A] FIG. 9A is an exploded perspective view schematically illustrating the configuration of a light emitting device according to a second exemplary embodiment of the present disclosure. [Figure 9B] FIG. 9B is a top view of the light emitting device shown in FIG. 9A. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, light emitting devices according to embodiments of the present disclosure will be described with reference to the drawings. Parts that appear in multiple drawings with the same reference numerals indicate the same or equivalent parts.

[0009] Furthermore, the following are examples to embody the technical idea of ​​the present invention, and are not intended to limit the present invention. Furthermore, descriptions of the size, material, shape, relative arrangement, etc. of components are intended for illustration purposes only, and are not intended to limit the scope of the present invention. The size and positional relationship of components shown in each drawing may be exaggerated to facilitate understanding.

[0010] Furthermore, in this specification or claims, when there are multiple elements corresponding to a certain element and each element needs to be distinguished, the elements may be distinguished by adding "first" or "second" to the beginning of the element. If the objects or viewpoints distinguished between this specification and the claims are different, the same notation may not refer to the same object between this specification and the claims.

[0011] (Embodiment 1) In some cases, a light emitting device is required to efficiently direct laser light emitted from multiple laser elements into a thin member such as a light guide plate. The light emitting device according to the first embodiment of the present disclosure can achieve such a light emitting device.

[0012] 1A and 1B, a configuration example of a light emitting device according to a first embodiment of the present disclosure will be described. In the following description, the light emitting device emits white laser light in which red, green, and blue laser light are superimposed, but the superimposed laser light is not limited to this combination.

[0013] 1A is an exploded perspective view schematically illustrating the configuration of a light emitting device 100A according to a first exemplary embodiment of the present disclosure. For reference, the drawing schematically illustrates an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other. The direction of the X-axis arrow is referred to as the +X direction, and the opposite direction is referred to as the -X direction. When there is no need to distinguish between the ±X directions, they are simply referred to as the X direction. The same applies to the Y-axis and the Z-axis. In this specification, the Y direction is also referred to as the "first direction," and the X direction is also referred to as the "second direction."

[0014] The light emitting device 100A shown in Fig. 1A includes a substrate 10, a first semiconductor laser element 20a, a second semiconductor laser element 20b, a third semiconductor laser element 20c, a first submount 22a, a second submount 22b, a third submount 22c, a first reflecting member 30a, a second reflecting member 30b, a third reflecting member 30c, a sidewall 40, and a cover 50. Fig. 1B is a top view of the light emitting device 100A shown in Fig. 1A. The cover 50 is not shown in Fig. 1B.

[0015] In the light emitting device 100A, the first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c are housed in a space defined by the substrate 10, the sidewall 40, and the cover 50. From the viewpoint of reliability, the first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c are preferably hermetically sealed inside the light emitting device 100A. The advantage of such hermetically sealed sealing increases as the wavelength of the laser light emitted from the first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c becomes shorter. This is because as the wavelength of the laser light becomes shorter, dust tends to collect in the part emitting the laser light, resulting in a decrease in the output power of the laser light.

[0016] In this specification, the first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c are collectively referred to as the "three semiconductor laser elements 20," and each of these semiconductor laser elements is also referred to as "each semiconductor laser element 20." Similarly, the first submount 22a, the second submount 22b, and the third submount 22c are collectively referred to as the "three submounts 22," and each of these submounts is also referred to as "each submount 22." Similarly, the first reflecting member 30a, the second reflecting member 30b, and the third reflecting member 30c are collectively referred to as the "three reflecting members 30," and each of these reflecting members is also referred to as "each reflecting member 30."

[0017] As shown in FIG. 1A, the substrate 10 has a top surface 10s that is parallel to the XY plane. In this specification, "A is parallel to B" means not only when A is strictly parallel to B, but also when the angle between A and B is 0° or more and 5° or less. The normal direction of the top surface 10s is the +Z direction. In this specification, the normal direction of the top surface 10s is referred to as "above," and viewing from the normal direction of the top surface 10s is referred to as "top view."

[0018] The first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c are indirectly provided on the upper surface 10s of the substrate 10 via the first sub-mount 22a, the second sub-mount 22b, and the third sub-mount 22c, respectively. The three semiconductor laser elements 20 may also be provided directly on the upper surface 10s of the substrate 10.

[0019] In the example shown in FIG. 1A, each semiconductor laser element 20 is an edge-emitting semiconductor laser element and is a rectangular parallelepiped extending in the X direction. Each semiconductor laser element 20 has an emission surface on one of two end surfaces intersecting the X direction. The first semiconductor laser element 20a has an emission surface on the end surface on the +X direction side. The first semiconductor laser element 20a emits a red first laser beam in the +X direction from the emission surface. The first laser beam is light in a transverse magnetic (TM) mode, and the polarization direction of the first laser beam immediately after emission is parallel to the Z direction. The dashed line in FIG. 1B represents a reference plane that includes the optical axis of the first laser beam emitted from the first semiconductor laser element 20a and is perpendicular to the top surface 10s. This reference plane crosses the first submount 22a. In this specification, "A is perpendicular to B" means not only when A is strictly perpendicular to B, but also when the angle between A and B is 85° or more and 95° or less.

[0020] The second semiconductor laser element 20b has an emission surface on its end surface on the -X direction side. The second semiconductor laser element 20b emits a green second laser light in the -X direction from its emission surface. The second laser light is light in TE (Transverse Electric) mode, and the polarization direction of the second laser light immediately after emission is parallel to the Y direction. The third semiconductor laser element 20c has an emission surface on its end surface on the -X direction side. The third semiconductor laser element 20c emits a blue third laser light in the -X direction from its emission surface. The third laser light is light in TE mode, and the polarization direction of the third laser light immediately after emission is parallel to the Y direction.

[0021] The second semiconductor laser element 20b and the second submount 22b are located on one side of the reference plane, that is, the -Y direction side, and the third semiconductor laser element 20c and the third submount 22c are located on the other side of the reference plane, that is, the +Y direction side. The second laser light and the third laser light are emitted in the same direction parallel to the reference plane.

[0022] The first laser light may be TE mode light, and the second and third laser lights may be TM mode light. Furthermore, the first laser light may be a laser light other than red, the second laser light may be a laser light other than green, and the third laser light may be a laser light other than blue.

[0023] When the laser light emitted from each semiconductor laser element 20 travels straight in the ±X directions, the laser light spreads at different speeds in the XY plane and the XZ plane as it travels in the ±X directions. The laser light spreads relatively quickly in the XZ plane and relatively slowly in the XY plane. The spot of the laser light has an elliptical shape in the far field in the YZ plane, with the major axis in the Z direction and the minor axis in the Y direction.

[0024] Each semiconductor laser element 20 has one or more waveguide regions extending in the X direction and one or more emission points. One of both end faces of the waveguide region is the emission face. In the waveguide region, light is amplified by stimulated emission at a resonance wavelength determined by the length of the waveguide region, and laser light is emitted from the emission point. If each semiconductor laser element 20 has multiple waveguide regions and multiple emission points, the multiple waveguide regions are aligned along the Y direction, and similarly, the multiple emission points are aligned along the Y direction.

[0025] When each semiconductor laser element 20 includes multiple emission points aligned along the Y direction and the number of emission points is even, the optical axis of the laser light corresponds to the midpoint between the optical axes of the laser light emitted from the two emission points near the center of the end face. When each semiconductor laser element 20 includes multiple emission points aligned along the Y direction and the number of emission points is odd, the optical axis of the laser light corresponds to the optical axis of the laser light emitted from the central emission point.

[0026] In the following description, the first semiconductor laser element 20a includes two waveguide regions aligned along the Y direction and two emission points aligned along the Y direction, while the second semiconductor laser element 20b and the third semiconductor laser element 20c each include one waveguide region and one emission point. The first semiconductor laser element 20a, which emits the first red laser light, is prone to output power degradation due to heat. The first semiconductor laser element 20a has two waveguide regions and increases the number of emission points, thereby reducing the optical density per emission point. This suppresses damage to the facet caused by heat generation due to increased optical density, thereby reducing the output power degradation of the first semiconductor laser element 20a.

[0027] The three reflecting members 30 are provided directly on the upper surface 10s of the substrate 10, but may also be provided indirectly via other members. The reference plane intersects the first reflecting member 30a. The second reflecting member 30b is located on one side of the reference plane, in the -Y direction, and the third reflecting member 30c is located on the other side of the reference plane, in the +Y direction.

[0028] The first reflecting member 30a includes a first reflecting surface 32a, two first side surfaces 34a, and a first rear surface 36a. The first reflecting surface 32a is inclined relative to the top surface 10s and faces diagonally upward. The normal direction of the first reflecting surface 32a is perpendicular to the first reflecting surface 32a and forms an acute angle with the normal direction of the top surface 10s. The first rear surface 36a is located on the opposite side of the first reflecting surface 32a. The two first side surfaces 34a are located between the first reflecting surface 32a and the first rear surface 36a. In the example shown in FIGS. 1A and 1B, each of the first side surfaces 34a and the first rear surface 36a is flat, but they may also be curved or have a concave or convex portion. Similarly, the second reflecting member 30b includes a second reflecting surface 32b, two second side surfaces 34b, and a second rear surface 36b. The positional relationship and shape of the second reflecting surface 32b, the two second side surfaces 34b, and the second back surface 36b are the same as those of the first reflecting surface 32a, the two first side surfaces 34a, and the first back surface 36a, respectively. The third reflecting member 30c includes a third reflecting surface 32c, two third side surfaces 34c, and a third back surface 36c. The positional relationship and shape of the third reflecting surface 32c, the two third side surfaces 34c, and the third back surface 36c are the same as those of the first reflecting surface 32a, the two first side surfaces 34a, and the first back surface 36a, respectively. In this specification, the first reflecting surface 32a is also referred to as the "first reflecting region," the second reflecting surface 32b is also referred to as the "second reflecting region," and the third reflecting surface 32c is also referred to as the "third reflecting region."

[0029] The first reflecting surface 32a reflects the first laser beam traveling in the +X direction in the +Z direction. The second reflecting surface 32b reflects the second laser beam traveling in the -X direction in the +Z direction. The third reflecting surface 32c reflects the third laser beam traveling in the -X direction in the +Z direction. The point on the first reflecting surface 32a where the direction of the optical axis of the first laser beam changes from the +X direction to the +Z direction is defined as a first point 38a. The point on the second reflecting surface 32b where the direction of the optical axis of the second laser beam changes from the -X direction to the +Z direction is defined as a second point 38b. The point on the third reflecting surface 32c where the direction of the optical axis of the third laser beam changes from the -X direction to the +Z direction is defined as a third point 38c. The positional relationship between the first point 38a, the second point 38b, and the third point 38c will be described later.

[0030] 1A, the first tilt angle, which is the angle between first reflecting surface 32a and top surface 10s, is 45°, but the first tilt angle is not limited to 45°. The first tilt angle can be, for example, between 30° and 60°. The same applies to the second tilt angle, which is the angle between second reflecting surface 32b and top surface 10s, and the third tilt angle, which is the angle between third reflecting surface 32c and top surface 10s.

[0031] 1B, the first rear surface 36a faces a portion of the second rear surface 36b and a portion of the third rear surface 36c, but may face the entire second rear surface 36b or the entire third rear surface 36c. In the example shown in FIG. 1B, the first rear surface 36a and the second rear surface 36b are in contact with each other at their opposing portions, but they may be spaced apart. Similarly, the first rear surface 36a and the third rear surface 36c are in contact with each other at their opposing portions, but they may be spaced apart.

[0032] In the example shown in FIG. 1B, the entire second side surface 34b on the +Y direction side, which is one of the two second side surfaces 34b, faces the entire third side surface 34c on the -Y direction side, which is one of the two third side surfaces 34c, but at least a portion of the second side surface 34b on the +Y direction side may face at least a portion of the third side surface 34c on the -Y direction side. In the example shown in FIG. 1B, the portions facing each other are in contact, but they may also be separated. As such, in this specification, "facing" includes not only facing and spaced apart from each other, but also contacting while still facing each other.

[0033] The first back surface 36a, the second back surface 36b, and the third back surface 36c are perpendicular to the reference plane, and the two first side surfaces 34a, the two second side surfaces 34b, and the third side surface 34c are parallel to the reference plane. The second semiconductor laser element 20b and the third semiconductor laser element 20c are arranged parallel to the reference plane, and the second laser light and the third laser light are emitted parallel to the reference plane. This configuration reduces the size in the Y direction of the substrate 10, which directly or indirectly supports the three semiconductor laser elements 20 and the three reflecting members 30. Note that the first back surface 36a, the second back surface 36b, and the third back surface 36c do not have to be perpendicular to the reference plane, and the first side surface 34a, the two second side surfaces 34b, and the third side surface 34c do not have to be parallel to the reference plane.

[0034] Next, with reference to Figures 2A and 2B, the manner in which laser light is emitted from light-emitting device 100A will be described. Figures 2A and 2B are cross-sectional views parallel to the XZ plane and the YZ plane, respectively, that schematically illustrate the manner in which laser light is emitted from light-emitting device 100A of Figure 1A. The areas enclosed by the dashed and dotted lines in Figures 2A and 2B represent the main portions of first laser light 20La and second laser light 20Lb, respectively. The area enclosed by the dashed and dotted lines in Figure 2B represents the main portion of third laser light 20Lc. The main portion refers to the portion of the laser light that has an intensity of 1 / e2 or more relative to the peak intensity. e is the base of the natural logarithm.

[0035] The first laser light 20La, which is reflected by the first reflecting member 30a and travels in the +Z direction, spreads relatively quickly in the XZ plane and relatively slowly in the YZ plane. The same is true for the second laser light 20Lb, which is reflected by the second reflecting member 30b and travels in the +Z direction, and the third laser light 20Lc, which is reflected by the third reflecting member 30c and travels in the +Z direction. Above the light-emitting device 100A, the first laser light 20La, the second laser light 20Lb, and the third laser light 20Lc, which pass through the cover 50 and travel while spreading, are superimposed to form a white laser light. The polarization direction of the first laser light 20La traveling in the +Z direction is parallel to the X direction. The polarization directions of the second laser light 20Lb and the third laser light 20Lc traveling in the +Z direction are parallel to the Y direction.

[0036] In this specification, the first laser light 20La, the second laser light 20Lb, and the third laser light 20Lc are collectively referred to as the "three-color laser light 20L," and each of the three color laser light is also referred to as the "each color laser light 20L."

[0037] In the light-emitting device 100A according to this embodiment, the arrangement of the three reflecting members 30 shown in FIG. 1B shortens the distance L1 between the second point 38b and the third point 38c in the Y direction, and shortens the distance L2 between the first point 38a and the second point 38b or the third point 38c in the X direction. In this case, the first point 38a, the second point 38b, and the third point 38c are located at approximately the same distance from each other and are close to each other, thereby reducing color unevenness in the three-color laser light 20L superimposed above the light-emitting device 100A. Furthermore, the short distance L1 allows the three-color laser light 20L to be efficiently incident on a thin member such as a light guide plate. The distance L1 is, for example, 0.8 mm or more and 1.2 mm or less, and the distance L2 is, for example, 1.2 mm or more and 1.7 mm or less.

[0038] Furthermore, in the light emitting device 100A according to this embodiment, the first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c are arranged on opposite sides of the three reflecting members 30, so that heat generated from the second semiconductor laser element 20b and the third semiconductor laser element 20c can be prevented from being transmitted to the first semiconductor laser element 20a. Therefore, even if a semiconductor laser element that is sensitive to heat is used as the first semiconductor laser element 20a, a decrease in the output of the first semiconductor laser element 20a due to heat can be prevented. The heat generated by the three semiconductor laser elements 20 is transmitted to the outside via the three submounts 22 and the substrate 10.

[0039] Next, with reference to FIGS. 3A and 3B, an example of the arrangement of three reflecting members 30 will be described. FIG. 3A is a top view schematically illustrating a first example of the arrangement of three reflecting members 30. In the example illustrated in FIG. 3A, the second reflecting member 30b and the third reflecting member 30c are arranged with an interval in the Y direction. Let a1 be the size of the first reflecting member 30a in the Y direction, b1 be the distance in the Y direction between the second side surface 34b on the +Y direction side of the second reflecting member 30b and the third side surface 34c on the −Y direction side of the third reflecting member 30c, c1 be the distance in the Y direction between the optical axis of the second laser light and the reference plane, d1 be the distance in the Y direction between the optical axis of the third laser light and the reference plane, e1 be the distance in the Y direction between the optical axis of the second laser light and the second side surface 34b on the +Y direction side of the second reflecting member 30b, and f1 be the distance in the Y direction between the optical axis of the third laser light and the third side surface 34c on the −Y direction side of the third reflecting member 30c. In this embodiment, the relationships a1>b1 and a1 / 2>c1-e1, and / or a1>b1 and a1 / 2>d1-f1 are satisfied. When such relationships are satisfied, the distance L1 can be shortened. Therefore, the three-color laser beams can be efficiently incident on a thin member such as a light guide plate.

[0040] FIG. 3B is a top view schematically showing a second example of the arrangement of the three reflecting members 30. In the example shown in FIG. 3B, the first reflecting member 30a and the second reflecting member 30b, and the first reflecting member 30a and the third reflecting member 30c are arranged at intervals in the X direction. Let the size of the first reflecting member in the X direction be a2, the distance in the X direction between the first rear surface 36a of the first reflecting member 30a and the second rear surface 36b of the second reflecting member 30b be b2, and the distance in the X direction between the first rear surface 36a of the first reflecting member 30a and the third rear surface 36c of the third reflecting member 30c be c2. In the present embodiment, the relationship b2 < a2 and c2 < a2 is satisfied. When such a relationship is satisfied, the distance L2 can be shortened. By shortening not only the distance L1 but also the distance L2, as described above, color unevenness of the three-color laser light to be superimposed can be reduced.

[0041] In the example shown in FIG. 3A, the first reflecting member 30a and the second reflecting member 30b, and the first reflecting member 30a and the third reflecting member 30c are arranged without a gap in the X direction. However, as long as the relationship b2 < a2 and c2 < a2 is satisfied, they may be arranged at intervals in the X direction. In the example shown in FIG. 3B, the second reflecting member 30b and the third reflecting member 30c are arranged without a gap in the Y direction. However, as long as the relationships a1 > b1 and a1 / 2 > c1 - e1, and / or a1 > b1 and a1 / 2 > d1 - f1 are satisfied, they may be arranged at intervals in the Y direction.

[0042] Next, referring to FIG. 4, a light-emitting device according to a reference example will be described. FIG. 4 is a top view schematically showing the configuration of a light-emitting device 90 according to the reference example. In FIG. 4, the description of the cover 50 is omitted. The difference between the light-emitting device 90 shown in FIG. 4 and the light-emitting device 100A shown in FIG. 1B is the arrangement of the three semiconductor laser elements 20, the three submounts 22, and the three reflecting members 30. The three semiconductor laser elements 20 are arranged so as to correspond to the three reflecting members 30 respectively. The three submounts 22 are arranged so as to support the three semiconductor laser elements 20 respectively.

[0043] When viewed from the Y direction, a portion of the first reflecting member 30a overlaps a portion of the second reflecting member 30b and a portion of the third reflecting member 30c. A portion of the first side surface 34a on the −Y direction side of the first reflecting member 30a is in contact with a portion of the second side surface 34b on the +Y direction side of the second reflecting member 30b. A portion of the first side surface 34a on the +Y direction side of the first reflecting member 30a is in contact with a portion of the third side surface 34c on the −Y direction side of the third reflecting member 30c. The first back surface 36a of the first reflecting member 30a does not face the second back surface 36b of the second reflecting member 30b, and does not face the third back surface 36c of the third reflecting member 30c. The first back surface 36a of the first reflecting member 30a is located closer to the +X direction than the second back surface 36b of the second reflecting member 30b and the third back surface 36c of the third reflecting member 30c. First reflecting member 30a protrudes in the −X direction further than second reflecting member 30b and third reflecting member 30c in a top view.

[0044] In the light-emitting device 90 shown in FIG. 4, although the distance L2 is short, the distance L1 is long, making it difficult to position the first point 38a, the second point 38b, and the third point 38c at approximately the same distance from one another. The distance between the second point 38b and the third point 38c is longer than the distance between the first point 38a and the third point 38c, and is also longer than the distance between the first point 38a and the second point 38b. In the light-emitting device 90 shown in FIG. 4, it is more difficult to superimpose the second laser light and the third laser light without color unevenness than in the light-emitting device 100A shown in FIG. 1B. Furthermore, because the distance L1 is long, it is difficult to efficiently direct the three color laser lights into a thin member such as a light guide plate.

[0045] Next, with reference to FIG. 5 , an example in which the light-emitting device 100A according to this embodiment is applied to a white backlight will be described. FIG. 5 is a perspective view schematically illustrating the configuration of a white backlight 200 according to an exemplary embodiment of the present disclosure. The white backlight 200 illustrated in FIG. 5 includes the light-emitting device 100A and a light guide plate 60. The light guide plate 60 includes a non-diffusion portion 60a and a diffusion portion 60b aligned along the Z direction. Light propagating through the light guide plate 60 is not diffused in the non-diffusion portion 60a but is diffused in the diffusion portion 60b. The light guide plate 60 includes a light-receiving surface 62 in the non-diffusion portion 60a and a light-emitting surface 64 in the diffusion portion 60b. The light-receiving surface 62 is a side surface of the light guide plate 60 and receives light emitted from the light-emitting device 100A. The light-emitting surface 64 emits light that enters through the light-receiving surface 62 and propagates through the light guide plate 60 to the outside. 5, the light receiving surface 62 of the light guide plate 60 receives light emitted from one light emitting device 100A, but may also receive light emitted from multiple light emitting devices 100A arranged along the light receiving surface 62.

[0046] 6A is a cross-sectional view parallel to the YZ plane, which schematically shows how three-color laser beams 20L emitted from the light-emitting device 100A according to this embodiment are incident on the light guide plate 60. In the example shown in FIG. 6A, white laser light formed by superimposing the three-color laser beams 20L is incident entirely on the light guide plate 60 via the light-receiving surface 62. In the light-emitting device 100A according to this embodiment, the distance L1 is short as shown in FIG. 1B, so that even a thin light guide plate 60 can easily receive all of the white laser beams emitted from the light-emitting device 100A.

[0047] 6B is a cross-sectional view parallel to the YZ plane, schematically illustrating how three-color laser beams 20L emitted from a light-emitting device 90 according to a reference example are incident on a light guide plate 60. The thickness of the light guide plate 60 shown in FIG. 6B is equal to the thickness of the light guide plate 60 shown in FIG. 6A. In the light-emitting device 90 according to the reference example, the distance L1 is long as shown in FIG. 4, and therefore, as shown in FIG. 6B, not all of the white laser beam is incident on the thin light guide plate 60. While all of the first laser beam 20La is incident on the light guide plate 60, part of the second laser beam 20Lb and part of the third laser beam 20Lc leak outside the light guide plate 60.

[0048] Next, with reference to FIGS. 7A and 7B, the results of an optical simulation will be described using a light-emitting device having a configuration similar to that of the light-emitting device 100A shown in FIGS. 1A and 1B as a calculation example and a light-emitting device having a configuration similar to that of the light-emitting device 90 shown in FIG. 4 as a reference example. In the following description, the same reference symbols as above will be used for the calculation example and the reference example. In the optical simulation, the diffusion of three-color laser light 20L emitted from the light-emitting devices of the calculation example and the reference example was calculated within the light guide plate 60. The calculation software Zemax OpticStudio (Zemax, Inc.) was used for the optical simulation. The calculation conditions were as follows: the number of light beams emitted from each semiconductor laser element 20 was 2.0 × 10. In the calculation example, the distance L1 shown in FIG. 1B was 1.0 mm, and the distance L2 shown in FIG. 1B was 1.43 mm. In the reference example, the distance L1 shown in FIG. 4 was 2.0 mm, and the distance L2 shown in FIG. 4 was 0.017 mm. 1B and 4, the maximum size in the X direction of each reflective member 30 was 0.92 mm, the size in the Y direction was 1.00 mm, and the maximum size in the Z direction was 0.92 mm. In the white backlight 200 shown in FIG. 5, the size in the X direction of the light guide plate 60 was 215 mm, and the size in the Z direction was 383 mm. Of the light guide plate 60, the size in the Z direction of the non-diffusion portion 60a was 144 mm, and the size in the Z direction of the diffusion portion 60b was 239 mm.

[0049] 7A is a diagram showing the results of calculating the intensity distribution in the light guide plate 60 of three-color laser light 20L emitted from a light-emitting device according to a calculation example. The intensity distribution of the laser light 20L of each color shown in FIG. 7A is the intensity distribution of the laser light 20L of each color when the white backlight 200 shown in FIG. 5 is viewed from the +Y direction. In the example shown in FIG. 7A, the intensity of the laser light increases as the color changes from black to white. The size in the Y direction of the light guide plate 60, i.e., the thickness, was 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, and 3.0 mm.

[0050] When the thickness of the light guide plate 60 is 1.0 mm, the thickness of the light guide plate 60 is equal to the distance L1. In this case, the second laser beam 20Lb and the third laser beam 20Lc spread as they travel, causing a portion of the second laser beam 20Lb and a portion of the third laser beam 20Lc to leak outside the light guide plate 60. In the example shown in FIG. 7A , when the thickness of the light guide plate 60 is 1.0 mm, the leakage of the third laser beam causes the intensity of the third laser beam to be high outside the light guide plate 60 and near the surface on the +Y direction side of the non-diffusion portion 60a. Although not shown in FIG. 7A , the leakage of the second laser beam causes the intensity of the second laser beam to be high outside the light guide plate 60 and near the surface on the −Y direction side of the non-diffusion portion 60a. As shown in FIG. 7A , increasing the thickness of the light guide plate 60 reduces leakage of the third laser beam, and therefore the intensity of the third laser beam decreases near the surface outside the light guide plate 60 and on the +Y direction side of the non-diffusion portion 60a. Similarly, increasing the thickness of the light guide plate 60 reduces leakage of the second laser beam, and therefore the intensity of the second laser beam decreases near the surface outside the light guide plate 60 and on the −Y direction side of the non-diffusion portion 60a. Because the first laser beam 20La does not leak outside the light guide plate 60 regardless of the thickness of the light guide plate 60 shown in FIG. 7A , increasing the thickness of the light guide plate 60 hardly changes the intensity distribution of the first laser beam 20La. As shown in FIG. 7A , when the thickness of the light guide plate 60 is 2.0 mm or greater, almost all of the three-color laser beam 20L can enter the light guide plate 60.

[0051] 7B is a diagram showing the calculation results of the intensity distribution in the light guide plate 60 of the three-color laser beam 20L emitted from the light-emitting device according to the reference example. When the thickness of the light guide plate 60 is equal to or less than the distance L1 of 2.0 mm, as shown in FIG. 7B, the intensity of the third laser beam is high outside the light guide plate 60 and near the surface on the +Y direction side of the non-diffusion portion 60a due to leakage of the third laser beam. Although not shown in FIG. 7B, the intensity of the second laser beam is high outside the light guide plate 60 and near the surface on the −Y direction side of the non-diffusion portion 60a due to leakage of the second laser beam. As shown in FIG. 7B, when the thickness of the light guide plate 60 is equal to or greater than 3.0 mm, almost all of the three-color laser beam 20L can enter the light guide plate 60.

[0052] 7A and 7B show that the light emitting device 100A according to this embodiment, unlike the light emitting device 90 according to the reference example, is capable of allowing all three color laser beams to be incident on the thin light guide plate 60. Therefore, a thin white backlight 200 can be realized.

[0053] Next, a modified example of the light emitting device 100A according to the present embodiment will be described with reference to FIGS. 8A and 8B. FIGS. 8A and 8B are cross-sectional views parallel to the XZ plane and the YZ plane, respectively, illustrating the emission of laser light from a light emitting device 110A according to a modified example of the present embodiment. The light emitting device 110A according to this modified example differs from the light emitting device 100A according to the present embodiment in that the light emitting device 110A further includes a half-wave plate 70 above the first reflecting member 30a and on the optical path of the first laser beam 20La. The half-wave plate 70 converts the first laser beam 20La from TM mode to TE mode. As a result, the light emitting device 110A can emit three-color laser beams 20L whose polarization directions are aligned in the Y direction.

[0054] 8A and 8B, the half-wave plate 70 is provided on the surface of the cover 50 that faces the upper surface 10s of the substrate 10. The half-wave plate 70 may be provided on the surface of the cover 50 opposite to the surface that faces the upper surface 10s of the substrate 10. However, because the first laser light 20La spreads as it travels from the inside to the outside of the light-emitting device 110A, providing the half-wave plate 70 inside the light-emitting device 110A allows the half-wave plate 70 to be smaller.

[0055] Alternatively, a single half-wave plate may be provided above the second reflecting member 30b on the optical path of the second laser beam 20Lb, and another half-wave plate may be provided above the third reflecting member 30c on the optical path of the third laser beam 20Lc. Alternatively, two half-wave plates may be provided on each optical path. The single or two half-wave plates convert the second laser beam 20Lb and the third laser beam 20Lc from TE mode to TM mode, respectively. As a result, the light emitting device 110A can emit three-color laser beams 20L whose polarization directions are aligned in the X direction.

[0056] Next, the material, shape, and size of each component included in light emitting devices 100A and 110A will be described.

[0057] [Substrate 10] The substrate 10 may be rectangular, circular, or elliptical in top view. The substrate 10 has wiring on its upper surface 10s. Power is supplied to the three semiconductor laser elements 20 via wires from the wiring. The substrate 10 also has external electrodes on the surface opposite the upper surface 10s, which are electrically connected to an external power supply device. Portions of the substrate 10 other than the wiring and external electrodes may be formed, for example, from ceramic containing at least one selected from the group consisting of AlN, SiC, silicon nitride, and alumina, or from metal or alloys containing at least one selected from the group consisting of Ag, Cu, W, Au, Ni, Pt, and Pd. When formed from ceramic, low-temperature co-fired ceramic (LTCC) may be used. The size of the substrate 10 in the X direction is 6.1 mm to 9.5 mm, the size in the Y direction is 5.0 mm to 7.2 mm, and the size in the Z direction is 0.4 mm to 1.0 mm.

[0058] [Three semiconductor laser elements 20] Each semiconductor laser element 20 may be, for example, a rectangular parallelepiped. The size of each semiconductor laser element 20 in the X direction may be, for example, 50 μm to 4 mm, the size in the Y direction may be, for example, 50 μm to 500 μm, and the size in the Z direction may be, for example, 20 μm to 150 μm.

[0059] Each semiconductor laser element 20 can emit violet, blue, green, or red laser light in the visible range, or infrared or ultraviolet laser light in the invisible range. The peak wavelength of the violet light is preferably in the range of 380 nm to 419 nm, more preferably in the range of 400 nm to 415 nm. The peak wavelength of the blue light is preferably 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 violet or blue laser light include semiconductor laser elements containing nitride semiconductor materials. Examples of nitride semiconductor materials that can be used include GaN, InGaN, and AlGaN. The peak wavelength of the green light is preferably 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 laser light include semiconductor laser elements containing nitride semiconductor materials. Examples of nitride semiconductor materials that can be used include GaN, InGaN, and AlGaN. The emission peak wavelength of the red light is preferably 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 laser light include semiconductor laser elements containing InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductor materials.

[0060] The first semiconductor laser element 20a, which emits laser light with a relatively long wavelength, may be mounted in a so-called face-up manner, and the second semiconductor laser element 20b and the third semiconductor laser element 20c, which emit laser light with a relatively short wavelength, may be mounted in a so-called face-down manner. Face-down mounting allows heat generated from each semiconductor laser element 20 to be transferred to the corresponding submount 22 more efficiently than face-up mounting. In face-down mounting, each semiconductor laser element 20 may be disposed on the corresponding submount 22 such that a tip portion including the emission surface of each semiconductor laser element 20 protrudes from the submount 22. Such an arrangement can prevent the submount 22 from blocking the progression of part of the emitted light.

[0061] The first semiconductor laser element 20a may be mounted face-down, and the second semiconductor laser element 20b and the third semiconductor laser element 20c may be mounted face-up.

[0062] A metal film is formed by, for example, plating on the upper surface of each semiconductor laser element 20 and the upper surface of the corresponding submount 22. The metal films provided on both upper surfaces are electrically connected via wires to wiring on the upper surface 10s of the substrate 10 in order to supply power to each semiconductor laser element 20.

[0063] [3 submounts 22] Although providing submounts 22 is not essential, if submounts 22 are provided, each submount 22 may be, for example, a rectangular parallelepiped. If the thermal conductivity of each submount 22 is higher than that of the substrate 10, heat generated from the corresponding semiconductor laser element 20 during operation can be efficiently transferred to the substrate 10. The submounts 22 may be formed from at least one selected from the group consisting of Cu, Al, Ag, Fe, Ni, Mo, Cu, W, CuW, CuMo, AlN, SiC, and alumina. The size of the submounts 22 in the X direction may be, for example, 0.3 mm to 5 mm, the size in the Y direction may be, for example, 0.3 mm to 4 mm, and the size in the Z direction may be, for example, 0.1 mm to 0.5 mm.

[0064] [Reflective member 30] Each reflecting member 30 is provided on the upper surface 10s. Each reflecting member 30 may be made of, for example, glass, quartz, synthetic quartz, sapphire, ceramic, plastic, silicon, metal, or a dielectric material. The reflecting surface of each reflecting member 30 is an inclined surface of the reflecting member 30, and a dielectric multilayer film made of, for example, a dielectric material may be separately formed on the inclined surface.

[0065] [Side wall 40] The sidewall 40 may be rectangular, circular, or elliptical in top view, for example. The shape of the sidewall 40 may be designed according to the shape of the substrate 10. The sidewall 40 may be formed from at least one selected from the group consisting of resin, Si, ceramic, glass, metal, and SPC (Steel Plate Colour) material, for example. When the substrate 10 and the sidewall 40 are integrally molded, the sidewall 40 is formed from the same material as the substrate 10. The sizes of the sidewall 40 in the X and Y directions are, for example, equal to the sizes of the substrate 10 in the X and Y directions, respectively. The size of the sidewall 40 in the Z direction may be, for example, 0.7 mm or more and 1.7 mm or less.

[0066] [Cover 50] The cover 50 may be rectangular, circular, or elliptical in top view. The shape of the cover 50 may be designed according to the shape of the sidewall 40. The cover 50 may be formed, for example, from at least one material selected from the group consisting of glass, quartz, synthetic quartz, sapphire, transparent ceramic, and plastic. The entire cover 50 may be translucent. Alternatively, the portion of the cover 50 through which the three-color laser light 20L passes may be translucent, while the remaining portion may not be translucent. The light transmittance of the translucent portion of the cover 50 for the three-color laser light may be, for example, 60% or more, preferably 70% or more, and more preferably 80% or more. An anti-reflection film may be provided on the light incident side, light exit side, or both of the translucent portion of the cover 50. The size of the cover 50 in the X and Y directions is, for example, equal to the size of the sidewall 40 in the X and Y directions, respectively. The size of the cover 50 in the Z direction may be, for example, 0.3 mm or more and 2.0 mm or less.

[0067] [1 / 2 wavelength plate 70] The half-wave plate 70 may be formed from a birefringent material such as quartz or a polymer. The thickness of the half-wave plate 70 is designed so that the phase difference between the electric field component parallel to the optical axis of the birefringent material and the electric field component perpendicular to the optical axis of the birefringent material is shifted by half a wavelength. When the optical axis of the birefringent material forming the half-wave plate 70 and the polarization direction of the first laser beam 20La form a 45° angle, the first laser beam 20La has an electric field component parallel to the optical axis of the birefringent material and an electric field component perpendicular to the optical axis of the birefringent material equally. When the first laser beam 20La passes through the half-wave plate 70 under these conditions, the polarization direction of the first laser beam 20La is rotated by 90°.

[0068] The size of the half wavelength plate 70 in the X direction is, for example, 0.8 mm to 2.9 mm, the size in the Y direction is, for example, 4.0 mm to 6.4 mm, and the size in the Z direction is, for example, 0.2 mm to 0.7 mm.

[0069] The joining of the different components can be done using known joining materials and known methods.

[0070] (Embodiment 2) As described above, the output of the first semiconductor laser element 20a emitting the first red laser light is more likely to decrease due to heat than the second semiconductor laser element 20b emitting the second green laser light and the third semiconductor laser element 20c emitting the third blue laser light. For this reason, it may be necessary to prevent the heat generated by the second semiconductor laser element 20b and the third semiconductor laser element 20c from being transferred to the first semiconductor laser element 20a. According to the light emitting device of the second embodiment of the present disclosure, such a light emitting device can be realized even with a single reflecting member 30 instead of three reflecting members 30.

[0071] An example configuration of a light emitting device according to embodiment 2 of the present disclosure will be described below with reference to Figures 9A and 9B, focusing on differences from the light emitting device according to embodiment 1. Figure 9A is an exploded perspective view schematically illustrating the configuration of a light emitting device 100B according to exemplary embodiment 2 of the present disclosure. Figure 9B is a top view of the light emitting device 100B shown in Figure 9A. In Figure 9B, the cover 50 is omitted.

[0072] The light-emitting device 100B shown in FIGS. 9A and 9B differs from the light-emitting device 100A shown in FIGS. 1A and 1B in that the light-emitting device 100B includes a single reflecting member 30d instead of three reflecting members 30. As shown in FIG. 9B, the reflecting member 30d includes a fourth reflecting surface 32d1, a fifth reflecting surface 32d2, and two fourth side surfaces 34d. The fourth reflecting surface 32d1 and the fifth reflecting surface 32d2 are located opposite each other. The two fourth side surfaces 34d are located between the fourth reflecting surface 32d1 and the fifth reflecting surface 32d2. In the example shown in FIG. 9A, the fourth tilt angle, which is the angle between the fourth reflecting surface 32d1 and the top surface 10s, is 45°, but the fourth tilt angle is not limited to 45°. The fourth tilt angle may be, for example, between 30° and 60°. The same applies to the fifth tilt angle, which is the angle between the fifth reflecting surface 32d2 and the top surface 10s.

[0073] The first semiconductor laser element 20a emits a first laser beam in TM mode toward a first reflecting region that is a part of the fourth reflecting surface 32d1. The dashed line in FIG. 9B represents a reference plane that is perpendicular to the top surface 10s and includes the optical axis of the first laser beam emitted from the first semiconductor laser element 20a. The second semiconductor laser element 20b emits a second laser beam in TE mode toward a second reflecting region that is a part of the fifth reflecting surface 32d2 on the −Y direction side of the reference plane. The third semiconductor laser element 20c emits a third laser beam in TE mode toward a third reflecting region that is a part of the fifth reflecting surface 32d2 on the +Y direction side of the reference plane. The second laser beam and the third laser beam are emitted in the same direction parallel to the reference plane. The positional relationship between the first point 38a, the second point 38b, and the third point 38c shown in FIG. 9B is as described with reference to FIG. 1B. The first laser light may be light in TE mode, and each of the second laser light and the third laser light may be light in TM mode.

[0074] The light emitting device 100B according to the second embodiment may be used in the white backlight 200 shown in Fig. 5. The light emitting device 100B according to the second embodiment may further include a half-wave plate 70 above the first reflection region and on the optical path of the first laser light, as shown in Figs. 8A and 8B.

[0075] In the light emitting device 100B according to the second embodiment, similarly to the light emitting device 100A according to the first embodiment, the first semiconductor laser element 20a, the second semiconductor laser element 20b, and the third semiconductor laser element 20c are arranged on opposite sides of the reflecting member 30d. Similarly to the light emitting device 100A, the light emitting device 100B can prevent heat generated from the second semiconductor laser element 20b and the third semiconductor laser element 20c from being transferred to the first semiconductor laser element 20a. Therefore, a decrease in the output power of the first semiconductor laser element 20a due to heat can be prevented. The heat generated by the three semiconductor laser elements 20 is transferred to the outside via the three submounts 22 and the substrate 10.

[0076] Furthermore, in the light-emitting device 100B according to the second embodiment, similar to the light-emitting device 100A according to the first embodiment, the distance L1 between the second point 38b and the third point 38c in the Y direction can be shortened, and the distance L2 between the first point 38a and the second point 38b or the third point 38c in the X direction can be shortened. In this case, the first point 38a, the second point 38b, and the third point 38c are located at approximately the same distance from each other and are close to each other, which reduces color unevenness in the three-color laser light 20L superimposed above the light-emitting device 100B. Furthermore, because the distance L1 is short, the three-color laser light 20L can be efficiently incident on a thin member via its side. The numerical ranges of the distances L1 and L2 are as described above.

[0077] The light emitting device of the present disclosure includes the light emitting device according to the following items. [Item 1] a substrate having a top surface; a first semiconductor laser element, a second semiconductor laser element, and a third semiconductor laser element provided directly or indirectly on the upper surface and emitting a first laser beam, a second laser beam, and a third laser beam, respectively; a first reflecting member, a second reflecting member, and a third reflecting member, each of which is provided directly or indirectly on the upper surface and includes a reflecting surface that is inclined with respect to the upper surface of the substrate and faces obliquely upward, a back surface located on the opposite side to the reflecting surface, and two side surfaces located between the reflecting surface and the back surface; Equipped with the back surface of the first reflecting member faces at least a portion of the back surface of the second reflecting member and at least a portion of the back surface of the third reflecting member; at least a portion of one of the two side surfaces of the second reflecting member faces at least a portion of one of the two side surfaces of the third reflecting member; a reflecting surface of the first reflecting member that reflects the first laser light, a reflecting surface of the second reflecting member that reflects the second laser light, and a reflecting surface of the third reflecting member that reflects the third laser light. [Item 2] A direction perpendicular to a reference plane that includes the optical axis of the first laser beam and is perpendicular to the upper surface is defined as the first direction. Let the size of the first reflecting member in the first direction be a1, the distance in the first direction between one of the two side surfaces of the second reflecting member and one of the two side surfaces of the third reflecting member be b1, the distance in the first direction between the optical axis of the second laser beam and the reference plane be c1, the distance in the first direction between the optical axis of the third laser beam and the reference plane be d1, the distance in the first direction between the optical axis of the second laser beam and one of the two side surfaces of the second reflecting member be e1, and the distance in the first direction between the optical axis of the third laser beam and one of the two side surfaces of the third reflecting member be f1. Then, The light-emitting device according to item 1, in which the relationship a1 > b1 and a1 / 2 > c1 - e1, or a1 > b1 and a1 / 2 > d1 - f1 is satisfied. [Item 3] A direction parallel to the optical axis of the first laser beam is defined as the second direction. Let the size of the first reflecting member in the second direction be a2, the distance in the second direction between the back surface of the first reflecting member and the back surface of the second reflecting member be b2, and the distance in the second direction between the back surface of the first reflecting member and the back surface of the third reflecting member be c2. Then, The light-emitting device according to item 1 or 2, in which the relationships b2 < a2 and c2 < a2 are satisfied. [Item 4] The back surfaces of each of the first reflecting member, the second reflecting member, and the third reflecting member are reference planes that include the optical axis of the first laser beam and are perpendicular to a reference plane that is perpendicular to the upper surface, the two side surfaces of each of the first reflecting member, the second reflecting member, and the third reflecting member are parallel to the reference plane, The light-emitting device according to item 1, in which the second laser beam and the third laser beam are emitted parallel to the reference plane. [Item 5] The light-emitting device according to any one of items 1 to 4, in which the first laser beam is red, the second laser beam is green, and the third laser beam is blue. [Item 6] the first laser beam is a TM mode beam, and the second laser beam and the third laser beam are TE mode beams, 6. The light emitting device according to any one of items 1 to 5, further comprising a half-wave plate above the first reflecting member and on the optical path of the first laser light. [Item 7] The light-emitting device according to any one of items 1 to 6, a light guide plate having a light receiving surface that receives light obtained by superimposing the first laser light, the second laser light, and the third laser light, and a light emitting surface; Equipped with The light exit surface emits the light that is incident from the light receiving surface and propagates through the light guide plate to the outside. [Item 8] a substrate having a top surface; One or more reflective members provided directly or indirectly on the upper surface, each having a first reflective area, and a second reflective area and a third reflective area located opposite the first reflective area; a first semiconductor laser element provided directly or indirectly on the upper surface and emitting a first red laser beam toward the first reflection region; a second semiconductor laser element provided directly or indirectly on the upper surface and emitting a second green laser beam toward the second reflection region; a third semiconductor laser element provided directly or indirectly on the upper surface and emitting a third blue laser beam toward the third reflective region; A light emitting device comprising: [Item 9] Item 9. The light emitting device according to item 8, wherein the second laser light and the third laser light are emitted in the same direction parallel to the reference plane. [Item 10] the first laser beam is a TM mode beam, and the second laser beam and the third laser beam are TE mode beams, Item 10. The light emitting device according to item 8 or 9, further comprising a half-wave plate above the first reflecting surface and on the optical path of the first laser light. [Item 11] The light-emitting device according to any one of items 8 to 10, a light guide plate having a light receiving surface that receives white light obtained by superimposing the first laser light, the second laser light, and the third laser light, and a light emitting surface; Equipped with The light exit surface emits the white light that is incident from the light receiving surface and propagates through the light guide plate to the outside. [Industrial Applicability]

[0078] The method for manufacturing a semiconductor device according to the present disclosure can be applied to light-emitting devices used in, for example, head-mounted displays, projectors, displays, and lighting fixtures. [Explanation of symbols]

[0079] 10 Substrate 10s top 20 Three semiconductor laser elements 20L 3 laser beams 20La first laser beam 20Lb second laser beam 20Lc Third laser beam 20a First semiconductor laser element 20b Second semiconductor laser element 20c Third semiconductor laser element 22 Three submounts 22a 1st submount 22b Second submount 22c 3rd submount 30 Three reflective elements 30a First reflecting member 30b Second reflecting member 30c Third reflecting member 30d Reflective material 32a 1st reflective surface 32b 2nd reflective surface 32c 3rd reflective surface 32d1 4th reflective surface 32d2 5th reflective surface 34a 1st side 34b Second side 34c 3rd side 34d 4th side 36a 1st back 36b 2nd back 36c 3rd back 38a 1st point 38b 2nd point 38c 3rd point 40 side wall 50 Cover 60 Light guide plate 60a Non-diffusion part 60b Diffusion part 62 Photosensitive surface 64 Light exit surface 70 1 / 2 wave plate 90 Light-emitting device 100A, 110A, 100B Light-emitting device 200 White Backlight

Claims

1. a substrate having a top surface; a first semiconductor laser element, a second semiconductor laser element, and a third semiconductor laser element, which are provided directly or indirectly on the upper surface and emit a first laser beam, a second laser beam, and a third laser beam, respectively; a first reflecting member, a second reflecting member, and a third reflecting member, each of which is provided directly or indirectly on the upper surface and includes a reflecting surface that is inclined with respect to the upper surface of the substrate and faces obliquely upward, a back surface located on the opposite side to the reflecting surface, and two side surfaces located between the reflecting surface and the back surface; Equipped with the rear surface of the first reflecting member faces at least a portion of the rear surface of the second reflecting member and at least a portion of the rear surface of the third reflecting member; at least a portion of one of the two side surfaces of the second reflecting member faces at least a portion of one of the two side surfaces of the third reflecting member; a reflecting surface of the first reflecting member that reflects the first laser light, a reflecting surface of the second reflecting member that reflects the second laser light, and a reflecting surface of the third reflecting member that reflects the third laser light.

2. Let a direction perpendicular to a reference plane that includes the optical axis of the first laser light and is perpendicular to the top surface be a first direction, a1 be the size of the first reflecting member in the first direction, b1 be the distance in the first direction between one of the two side surfaces of the second reflecting member and one of the two side surfaces of the third reflecting member, c1 be the distance in the first direction between the optical axis of the second laser light and the reference plane, d1 be the distance in the first direction between the optical axis of the third laser light and the reference plane, e1 be the distance in the first direction between the optical axis of the second laser light and one of the two side surfaces of the second reflecting member, and f1 be the distance in the first direction between the optical axis of the third laser light and one of the two side surfaces of the third reflecting member.

2. The light emitting device according to claim 1, wherein the relationship a1>b1 and a1 / 2>c1-e1, or a1>b1 and a1 / 2>d1-f1 is satisfied.

3. When a direction parallel to the optical axis of the first laser light is defined as a second direction, a2 is the size of the first reflecting member in the second direction, b2 is the distance in the second direction between the back surface of the first reflecting member and the back surface of the second reflecting member, and c2 is the distance in the second direction between the back surface of the first reflecting member and the back surface of the third reflecting member, 3. The light emitting device according to claim 1, wherein the relationships b2<a2 and c2<a2 are satisfied.

4. the back surface of each of the first reflecting member, the second reflecting member, and the third reflecting member is perpendicular to a reference plane that includes an optical axis of the first laser light and is perpendicular to the top surface; the two side surfaces of each of the first reflecting member, the second reflecting member, and the third reflecting member are parallel to the reference plane; The light emitting device according to claim 1 , wherein the second laser light and the third laser light are emitted parallel to the reference plane.

5. The light emitting device according to claim 1 , wherein the first laser light is red, the second laser light is green, and the third laser light is blue.

6. the first laser beam is a TM mode beam, and the second laser beam and the third laser beam are TE mode beams, The light emitting device according to claim 1 , further comprising a half-wave plate above the first reflecting member and on the optical path of the first laser light.

7. A light emitting device according to any one of claims 1 to 6; a light guide plate having a light receiving surface that receives light obtained by superimposing the first laser light, the second laser light, and the third laser light, and a light emitting surface; Equipped with The light exit surface emits the light that is incident from the light receiving surface and propagates through the light guide plate to the outside.

Images