Light-emitting device

Abstract

To provide a compact light emitting device.SOLUTION: A light emitting device comprises: a first light emitting element having a first light emitting surface that emits first light in the first direction; a second light emitting element having a second light emitting surface that emits a second light in the first direction; an optical member that reflects some of the first light emitted in the first direction from the first light emitting element and transmits the remaining light, and reflects some of the second light emitted in the first direction from the second light emitting element and transmits the remaining light; and a photodetector that receives the first and second light reflected through the optical member. The optical path length of the first light emitted from the first light emitting surface to reach the photodetector and the optical path length of the second light emitted from the second light emitting surface to reach the photodetector are 1.5 mm or less.SELECTED DRAWING: Figure 5

Description

[Technical Field]

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

[0002] Conventionally, there have been light emitting devices in which multiple components are mounted in a package. The multiple components include, for example, multiple light emitting elements. In addition to the light emitting elements, other components such as Zener diodes, thermistors, or photodiodes may also be included.

[0003] For example, Patent Document 1 discloses an illumination light source in which a portion of the laser light focused on a phosphor material and a portion of the fluorescence emitted from the phosphor material are monitored by two photodiodes, respectively.

[0004] By mounting multiple components within a package, light-emitting devices can be made more powerful and multifunctional. However, there is also a demand for smaller light-emitting devices and units incorporating such light-emitting devices. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2011-527518 Summary of the Invention [Problem to be solved by the invention]

[0006] A light-emitting device equipped with a light-emitting element and a photodetector is miniaturized. [Means for solving the problem]

[0007] In one embodiment, the light emitting device of the present disclosure comprises: a package having a light extraction surface with a translucent region; a first light emitting element arranged inside the package and having a light exit surface that emits divergent light; an optical element arranged inside the package that receives the divergent light emitted from the first light emitting element, reflects a portion of the divergent light that has entered, and transmits the remaining light; and a photodetector arranged inside the package that has a light receiving surface that receives the divergent light emitted from the first light emitting element and reflected by the optical element, and the light emitted from the first light emitting element and transmitted through the optical element is emitted to the outside of the package from the translucent region.

[0008] In one embodiment, the light-emitting device of the present disclosure includes a first light-emitting element having a first light-emitting surface that emits first light in a first direction, a second light-emitting element having a second light-emitting surface that emits second light in the first direction, an optical element that reflects a portion of the first light emitted from the first light-emitting element in the first direction and transmits the remaining light, and that reflects a portion of the second light emitted from the second light-emitting element in the first direction and transmits the remaining light, and a photodetector that receives the first light and second light reflected through the optical element, wherein the optical path length of the first light from the first light-emitting surface to the photodetector and the optical path length of the second light from the second light-emitting surface to the photodetector are 1.5 mm or less. [Effects of the Invention]

[0009] According to the light emitting device of the present disclosure, it is possible to achieve miniaturization of the light emitting device. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of the light emitting device according to the first embodiment. [Figure 2] FIG. 2 is a perspective view of the light emitting device according to the first embodiment with the package cap removed. [Figure 3] FIG. 3 is a top view of the light emitting device according to the first embodiment with the package cap removed. [Figure 4] FIG. 4 is a top view of the light emitting device according to the first embodiment, with the package and lens member removed. [Figure 5] FIG. 5 is a cross-sectional view of the light emitting device taken along the line VV in FIG. [Figure 6] FIG. 6 is a perspective view of the photodetector and optical members according to the first embodiment. [Figure 7] FIG. 7 is an enlarged top view of the inside of the package according to the first embodiment. [Figure 8] FIG. 8 is an enlarged view of a portion X in the top view of FIGS. 3 and 7, with the optical member 40 removed. [Figure 9] FIG. 9 is a cross-sectional view of the photodetector and its surrounding area taken along the line IX-IX in FIG. [Figure 10] FIG. 10 is a diagram schematically showing the divergence of light emitted from a light-emitting element. [Figure 11] FIG. 11 is a diagram showing a schematic diagram of the relationship between the half angle of divergence of light emitted from two adjacent light-emitting elements and the distance from the light-emitting elements to the light-receiving surface. [Figure 12] FIG. 12 is a cross-sectional view of the light emitting device according to the second embodiment. [Figure 13] FIG. 13 is an enlarged top view of a portion X in the modified example. [Figure 14] FIG. 14 is a cross-sectional view of the photodetector and its surrounding area taken along the line XIV-XIV in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] In this specification and claims, polygons such as triangles and quadrilaterals are not limited to polygons in the strict mathematical sense, but also include shapes in which the corners of the polygon have been processed, such as rounded, chamfered, corner-cut, or rounded. Furthermore, shapes in which processing has been applied not only to the corners (edges) of polygons, but also to the middle portions of the edges are also referred to as polygons. In other words, shapes in which partial processing has been applied while retaining the polygonal base are included in the "polygon" described in this specification and claims.

[0012] This is not limited to polygons, but also applies to words that describe specific shapes such as trapezoids, circles, and irregularities. The same applies when dealing with the sides that form the shape. In other words, even if the corners or middle part of a side are processed, the processed part is included in the "side." When distinguishing a "polygon" or "side" that has no processing from a processed shape, the word "strict" is added, for example, "strict quadrilateral."

[0013] In this specification or claims, when there are multiple elements identified by a certain name and each element needs to be distinguished, an ordinal number such as "first" or "second" may be added to the beginning of each element. For example, if a claim states that "light-emitting elements are arranged on a substrate," the specification may state that "first and second light-emitting elements are arranged on a substrate." The ordinal numbers "first" and "second" are used simply to distinguish between the two light-emitting elements. The order of these ordinal numbers has no particular significance. Element names with the same ordinal number attached may not refer to the same element between the specification and the claims. For example, when elements specified by the terms "first light-emitting element," "second light-emitting element," and "third light-emitting element" are described in the specification, the "first light-emitting element" and "second light-emitting element" in the claims may correspond to the "first light-emitting element" and "third light-emitting element" in the specification. Furthermore, when the term "first light-emitting element" is used but the term "second light-emitting element" is not used in claim 1 described in the claims, the invention according to claim 1 may be provided with one light-emitting element, and the light-emitting element may be: The term is not limited to the "first light emitting element" in the specification, but may be the "second light emitting element" or the "third light emitting element."

[0014] In this specification or claims, terms indicating specific directions or positions (for example, "up," "down," "right," "left," and other terms including these terms) may be used. These terms are used merely to facilitate understanding of relative directions or positions in the referenced drawings. As long as the relationship of relative directions or positions indicated by terms such as "up" and "down" in the referenced drawings is the same, drawings other than those of this disclosure, actual products, manufacturing equipment, etc. may not be arranged in the same manner as in the referenced drawings.

[0015] The dimensions, dimensional ratios, shapes, spacing, etc. of elements or components shown in the drawings may be exaggerated for clarity, and some elements may be omitted to avoid overly complicated drawings.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments embody the technical ideas of the present invention, but do not limit the present invention. The numerical values, shapes, materials, steps, and the order of steps shown in the description of the embodiments are merely examples, and various modifications are possible as long as no technical contradiction occurs. In the following description, elements identified by the same names and symbols are the same or similar elements, and redundant descriptions of these elements may be omitted.

[0017] First Embodiment A light emitting device 100 according to a first embodiment will be described. FIGS. 1 to 11 are diagrams illustrating an exemplary embodiment of the light emitting device 100. FIG. 1 is a perspective view of the light emitting device 100 according to this embodiment. FIG. 2 is a perspective view of the light emitting device 100 with the cap 16 of the package 10 removed. FIG. 3 is a top view similar to FIG. 2. FIG. 4 is a top view of the light emitting device 100 with the package 10 and lens member 80 removed. FIG. 5 is a cross-sectional view taken along the VV line in FIG. 1. FIG. 6 is a perspective view of the photodetector 50 and the optical member 40. FIG. 7 is an enlarged top view of the interior of the package 10. FIG. 8 is an enlarged view of a portion X in the top views of FIGS. 3 and 7 to illustrate the photodetector 50. Note that in FIG. 8, the optical member 40 is omitted to make the photodetector 50 easier to see. FIG. 9 is a cross-sectional view of the photodetector 50 and its surrounding area taken along the IX-IX line in FIG. 8. FIG. 10 is a schematic diagram illustrating how light emitted from the light emitting element 20 travels. Figure 11 is a diagram showing a schematic diagram illustrating the relationship between the half divergence angles θ1, θ2 of light emitted from two light-emitting elements 20 arranged at a pitch P12, the optical path lengths L1, L2 from the light-emitting elements 20 to the light-receiving surface 52, and the size of the irradiation area 22 on the light-receiving surface 52 of the photodetector 50.

[0018] The light emitting device 100 of this embodiment comprises, as components, a package 10, one or more light emitting elements 20, a submount 30, an optical element 40, a photodetector 50, a protection element 60A, a temperature measurement element 60B, multiple wirings 70, a lens element 80, and a substrate 90.

[0019] In the illustrated example of the light emitting device 100, three light emitting elements 20, a submount 30, an optical member 40, a photodetector 50, a protective element 60A, a temperature measuring element 60B, and a plurality of wirings 70 (71, 72) are arranged in the space inside the package 10. The divergent light emitted from the three light emitting elements 20 is respectively emitted to the outside from the package 10 and then collimated by a lens member 80. A portion of the divergent light emitted from each of the three light emitting elements 20 is irradiated onto the photodetector 50. The photodetector 50 provides an output signal corresponding to the intensity of the received divergent light and can be used to monitor the intensity of the light emitted from the light emitting device 100.

[0020] First, each component will be described.

[0021] (Package 10) The package 10 has a base 11 including a mounting surface 11M, and a sidewall 12 surrounding the mounting surface 11M. The mounting surface 11M of the base 11 is an area on which other components are arranged. The package 10 also has a substrate 15 and a cap 16 fixed to the substrate 15. The substrate 15 has the base 11, and the cap 16 has the sidewall 12. In the following description, the substrate 15 and the substrate 90 may be referred to as a first substrate 15 and a second substrate 90, respectively, to distinguish them from each other.

[0022] In the illustrated example, the cap 16 includes a top surface (lid portion) facing the mounting surface 11M, with the other components arranged on the mounting surface 11M sandwiched therebetween, and a side surface (frame portion) surrounding the other components arranged on the mounting surface 11M. The side surface of the cap 16 includes a side wall portion 12. Note that the side wall portion 12 does not have to be configured as part of the cap 16. For example, the package 10 can be replaced with a package configured by a single member in which the base portion 11 and the side wall portion 12 are integrated, and another member having a top surface.

[0023] When viewed from above, the outer shapes of both the base 11 and the cap 16 are rectangular. However, these outer shapes do not necessarily have to be rectangular, and may be polygonal shapes other than quadrangles, or shapes that include curves, bends, or irregularities in part or in whole.

[0024] The base 11 has one or more upper surfaces. The one or more upper surfaces of the base 11 include a mounting surface 11M. The one or more upper surfaces of the base 11 include a peripheral region 11P surrounding the mounting surface 11M. In the example of the light emitting device 100 shown in the figure, the mounting surface 11M and the peripheral region 11P are located on the same plane. However, they do not have to be on the same plane; for example, the mounting surface 11M and the peripheral region 11P may be provided on different upper surfaces having a difference in height.

[0025] The peripheral region 11P is a region to which the cap 16 is bonded. The peripheral region 11P is provided between the outline of the base 11 and the outline of the mounting surface 11M in a top view. In the example of the light emitting device 100 shown in the figure, the outline of the mounting surface 11M is rectangular in a top view, and the peripheral region 11P is provided over the four sides of this rectangle. The lower surface of the side portion of the cap 16 is bonded to the upper surface of the peripheral region 11P. A metal film for bonding to the cap 16 may be provided in the peripheral region 11P.

[0026] As illustrated in FIG. 5, the package 10 has a light-transmitting region 13, which is a region having light-transmitting properties. The package 10 also has a light-extraction surface 10A that includes the light-transmitting region 13. This light-extraction surface 10A is included in one of one or more outer surfaces of the side wall portion 12 of the package 10. Having light-transmitting properties means that the transmittance of the main light incident thereon is 80% or more. For example, if infrared light is the main light, then a material can be said to have light-transmitting properties if its transmittance for infrared light is 80% or more.

[0027] The package 10 may have light-transmitting properties in one or more outer surfaces other than the light-transmitting region 13. The package 10 may also have a non-light-transmitting region (a region that does not have light-transmitting properties) in part. The entire side wall 12 of the package 10 does not need to be light-transmitting. In the example shown in the figure, the package 10 has four rectangular outer surfaces, and all four surfaces are light-transmitting, but only one surface is the light extraction surface 10A.

[0028] The entire cap 16 may be made of a light-transmitting material, or only the side surface may be made of a light-transmitting material. A portion including the light extraction surface 10A may be made of a first light-transmitting material, and the other portion may be made of a second light-transmitting material or a non-light-transmitting material.

[0029] The cap 16 may be formed integrally with its top and side portions. For example, it is possible to fabricate the cap 16 into a desired shape, such as a box-like shape, from a translucent material such as glass, plastic, or quartz using processing techniques such as molding or etching. The cap 16 may also be formed by joining a top portion (lid portion) and a side portion (frame portion) formed separately from different materials. For example, the top portion may be primarily made of monocrystalline or polycrystalline silicon, while the side portions may be primarily made of glass. The cap 16 may have, for example, a height of 2.5 mm or less and a rectangular outer side length of 8 mm or less when viewed from above. It may also have, for example, a height of 2 mm or less and a rectangular outer side length of 4 mm or less when viewed from above.

[0030] In the illustrated example of the light emitting device 100, the light extraction surface 10A is perpendicular to the direction in which the mounting surface 11M extends (horizontal direction). Note that the term "perpendicular" here includes a difference of ±5 degrees or less. Furthermore, the light extraction surface 10A does not need to be perpendicular to the direction in which the mounting surface 11M of the base 11 extends (horizontal direction), and may be inclined.

[0031] A plurality of wiring regions 14 are provided on the mounting surface 11M. Note that in FIG. 7, instead of assigning reference numerals to all of the wiring regions 14, all of the wiring regions 14 are hatched in the same manner. The plurality of wiring regions 14 may pass through the inside of the base 11 and be electrically connected to a wiring region provided on the lower surface of the base 11. A wiring region electrically connected to the wiring region 14 may be provided not only on the lower surface of the base 11 but also on another outer surface (upper surface or outer surface) of the base 11. The plurality of wiring regions 14 may be formed from a conductor such as a metal and may be a patterned film, layer, or via.

[0032] The first substrate 15 can be formed primarily from ceramic. Examples of ceramics that can be used for the first substrate 15 include aluminum nitride, silicon nitride, aluminum oxide, and silicon carbide.

[0033] In this embodiment, the first substrate 15 may be formed, for example, from a ceramic substrate having a plurality of metal vias therein. The first substrate 15 preferably includes a material with better heat dissipation properties (higher thermal conductivity) than ceramic in the portion that comes into thermal contact with the heat-generating component. Examples of such materials include copper, aluminum, iron, copper molybdenum, copper tungsten, and a copper-diamond composite.

[0034] (Light emitting element 20) An example of the light-emitting element 20 is a semiconductor laser element. The light-emitting element 20 may have a rectangular outer shape when viewed from above. When the light-emitting element 20 is an edge-emitting semiconductor laser element, the side surface that intersects with one of the two short sides of the rectangle when viewed from above is the light-emitting end surface (light-emitting surface 21). In this example, the upper and lower surfaces of the light-emitting element 20 have a larger area than the light-emitting surface 21. The light-emitting element 20 is not limited to an edge-emitting semiconductor laser element, but may also be a surface-emitting semiconductor laser element or a light-emitting diode (LED).

[0035] The light-emitting element 20 is a single-emitter element having at least one emitter. However, the light-emitting element 20 may be a multi-emitter element having two or more emitters. When the light-emitting element 20 is a semiconductor laser element having multiple emitters, one common electrode can be provided on either the top or bottom surface of the light-emitting element 20, and two electrodes corresponding to the respective emitters can be provided on the other surface.

[0036] The light emitted from the light emitting surface 21 of the light emitting element 20 is divergent light having a spread. However, it does not have to be divergent light. When the light emitting element 20 is a semiconductor laser element, The divergent light (laser light) emitted from the laser forms an elliptical far-field pattern (FFP) in a plane parallel to the light-emitting surface. The FFP is the shape and light intensity distribution of the emitted light at a position away from the light-emitting surface.

[0037] The light passing through the center of the elliptical shape of the FFP, in other words, the light with peak intensity in the light intensity distribution of the FFP, is called the light traveling along the optical axis. Also, the optical path of the light traveling along the optical axis is called the optical axis of that light. Also, in the light intensity distribution of the FFP, the light with a peak intensity of 1 / e 2 Light having an intensity equal to or greater than this will be referred to as the "main portion" of light.

[0038] In the elliptical shape of the FFP of light emitted from the light emitting element 20, which is a semiconductor laser element, the minor axis direction of the ellipse is referred to as the horizontal direction of the FFP, and the major axis direction is referred to as the vertical direction of the FFP. Multiple layers, including an active layer, that constitute the semiconductor laser element are stacked in the vertical direction of the FFP.

[0039] Based on the light intensity distribution of the FFP, the angle equivalent to the full width at half maximum of the light intensity distribution is defined as the light divergence angle of the semiconductor laser element. The light divergence angle in the vertical direction of the FFP is called the vertical divergence angle, and the light divergence angle in the horizontal direction of the FFP is called the horizontal divergence angle.

[0040] For example, a semiconductor laser element that emits blue light, a semiconductor laser element that emits green light, or a semiconductor laser element that emits red light can be used as the light emitting element 20. Also, a semiconductor laser element that emits light other than these may be used.

[0041] Here, blue light refers to light whose peak emission wavelength is in the range of 420 nm to 494 nm, green light refers to light whose peak emission wavelength is in the range of 495 nm to 570 nm, and red light refers to light whose peak emission wavelength is in the range of 605 nm to 750 nm.

[0042] Examples of semiconductor laser elements that emit blue light or green light include semiconductor laser elements that contain nitride semiconductors. Examples of nitride semiconductors that can be used include GaN, InGaN, and AlGaN. Examples of semiconductor laser elements that emit red light include those that contain InAlGaP-based, GaInP-based, GaAs-based, and AlGaAs-based semiconductors.

[0043] (Submount 30) The submount 30 has two bonding surfaces and is configured in the shape of a rectangular parallelepiped. One bonding surface is provided on the opposite side of the other bonding surface. The distance between the two bonding surfaces is smaller than the distance between the other two opposing surfaces. The shape of the submount 30 is not limited to a rectangular parallelepiped. The submount 30 can be formed using, for example, silicon nitride, aluminum nitride, or silicon carbide. A metal film for bonding is provided on the bonding surfaces.

[0044] (Optical member 40) The optical element 40 has a partially reflective surface 41 (FIGS. 5 and 6). The "partial" in the term "partially reflective surface" means that it reflects only a portion of the incident light (partial reflection). The partially reflective surface 41 reflects a portion of the incident light and transmits the remaining light. The traveling direction of the light reflected by the partially reflective surface 41 is tilted from a direction antiparallel to the traveling direction of the incident light. In other words, the partially reflective surface 41 functions as a beam splitter.

[0045] The light incident on the partially reflecting surface 41 is split into two beams of light that travel in different directions. The two beams of light that are reflected contain light of the same wavelength. The optical member 40 splits the same wavelength component of the incident light into two at a predetermined ratio.

[0046] For example, one of the two lights separated by the optical member 40 can be used as a main light, and the other can be used as a monitor light for controlling the main light. Alternatively, for example, each of the two lights can be used as a main light.

[0047] When incident light is split into main light and monitor light, the intensity of the monitor light is smaller than that of the main light. The partially reflective surface 41, for example, transmits 80% or more of the incident light to be used as the main light, and reflects 20% or less of the incident light to be used as the monitor light. The intensity of the monitor light may be 5% to 10% of the intensity of the main light. For example, it may be about 5% or less.

[0048] The reflectance of the partially reflective surface 41 for visible light can be set, for example, in the range of 0.5% to 20.0%. It can also be set, for example, in the range of 2.0% to 10.0%. The reflectance of the partially reflective surface 41 can vary depending on the wavelength of the incident light. Therefore, when light of different colors is incident on one partially reflective surface 41, the reflectance may differ depending on the color. It is not necessary to set the reflectance to be the same for all colors of light. It is sufficient to design the partially reflective surface 41 to have an appropriate reflectance for the target light to be reflected.

[0049] When light of different colors is incident, partially reflective surface 41 may have, for example, a reflective area with a reflectance suited to the light for each area where light of each color is incident. The multiple reflective areas corresponding to the areas where light of each color is incident may be separated from each other, or may have overlapping areas.

[0050] The partially reflective surface 41 is inclined with respect to the lower surface (horizontal plane) of the optical member 40. The partially reflective surface 41 is configured as a flat surface that forms an inclination angle of, for example, 40 degrees or more and 50 degrees or less with respect to the lower surface of the optical member 40. In the example of the light-emitting device 100 shown in the figures, the partially reflective surface 41 is configured as a flat surface that forms an inclination angle of 45 degrees with respect to the lower surface. This inclination angle may be in the range of 10 degrees or more and 80 degrees or less.

[0051] The optical element 40 may have a configuration in which two prisms (transparent triangular prisms) are bonded together with a thin metal film interposed therebetween. This thin metal film functions as a partially reflective surface 41. The reflectance can be controlled by adjusting the type and thickness of the thin metal film. A dielectric multilayer film may be used instead of the thin metal film. Instead of using two prisms, the optical element 40 may be formed from a single prism with a thin metal film or a dielectric multilayer film deposited on its inclined surface. Alternatively, the optical element 40 may simply reflect a portion of the incident light by utilizing Fresnel reflection that occurs at the interface between air and a dielectric.

[0052] The optical member 40 is formed in the shape of a rectangular parallelepiped. However, the shape of the optical member 40 is not limited to a rectangular parallelepiped. The optical member 40 also has an upper surface parallel to its lower surface. In order to fix the optical member 40 to another member, it is preferable that a part of the optical member 40 includes a bonding surface. For example, the lower surface of the optical member 40 can function as a bonding surface for the member located below. One or both of a pair of side surfaces of the optical member 40 may also function as a bonding surface. Furthermore, for example, the upper surface of the optical member 40 may function as a bonding surface for the other member.

[0053] (Photodetector 50) The photodetector 50 has a bonding surface 51 and a light-receiving surface 52. The bonding surface 51 is the surface opposite to the light-receiving surface 52. The photodetector 50 has a top surface, a bottom surface, and one or more side surfaces. The upper surface of the photodetector 50 is a light receiving surface 52. The outer shape of the photodetector 50 is a rectangular parallelepiped. However, the outer shape may be different from a rectangular parallelepiped.

[0054] One or more light-receiving regions 53 are provided on the light-receiving surface 52. Each of the one or more light-receiving regions 53 is a photoelectric conversion element that outputs an electrical signal in response to the intensity or amount of incident light. A typical example of such a photoelectric conversion element is a photodiode. Each photodiode can be formed, for example, by doping p-type impurity ions into a predetermined region of an n-type Si substrate. In this case, the light-receiving region 53 is defined by a p-type impurity region doped with p-type impurity ions. In the example of the photodetector 50 shown in FIG. 9, multiple p-type impurity regions are formed at predetermined positions in contact with the upper surface (light-receiving surface 52) of an n-type semiconductor substrate 58, and each p-type impurity region functions as a light-receiving region 53. The n-type semiconductor substrate 58 may have an epitaxial layer on its surface. A pn ​​junction is formed at the boundary between the p-type impurity region and the n-type impurity region, functioning as a diode. The potential of the p-type impurity region (light-receiving region 53) is determined by the potential of the anode electrode electrically connected to the p-type impurity region, and the potential of the n-type impurity region is determined by the cathode electrode electrically connected to the n-type impurity region (n-type Si substrate). When a reverse bias voltage is applied to the pn junction and light is incident on each light-receiving region 53, electron-hole pairs are generated, and a current flows between each anode electrode and the cathode electrode common to all the light-receiving regions 53. Based on this current, the intensity or amount of light incident on each light-receiving region 53 can be determined. Note that the p-type and n-type conductivity types may be reversed, and the type of semiconductor is not limited to Si.

[0055] In the illustrated example of the photodetector 50, three light receiving regions 53 are provided on the light receiving surface 52 of the photodetector 50. The number of light receiving regions 53 does not have to be limited to three. The multiple light receiving regions 53 are arranged side by side at a predetermined interval. Here, the direction in which the multiple light receiving regions 53 are arranged is referred to as the "first direction." Furthermore, the direction perpendicular to the first direction in a top view is referred to as the "second direction." In FIGS. 7 and 8, the 1D arrow indicates the "first direction" in the illustrated example of the photodetector 50, and the 2D arrow indicates the "second direction."

[0056] The light receiving surface 52 has a rectangular outer shape. Furthermore, the length of the light receiving surface 52 in the first direction is greater than the length in the second direction. Note that the length of the light receiving surface of the photodetector 50 in the first direction may be the same as the length in the second direction. Furthermore, the length in the second direction may be greater than the length in the first direction. In the illustrated example of the light emitting device 100, the length in the first direction is greater than the length in the second direction, which contributes to the miniaturization of the light emitting device 100.

[0057] The multiple light-receiving regions 53 are arranged at intervals. That is, the light-receiving regions 53 are spaced apart and do not overlap. The intervals do not have to be constant. The multiple light-receiving regions 53 are arranged close to each other. The interval between adjacent light-receiving regions 53 is smaller than the width in the first direction (X1, X2, or X3) of at least one of the adjacent light-receiving regions 53. The interval between adjacent light-receiving regions 53 is also smaller than the width in the first direction (X1 and X2, or X2 and X3) of either of the adjacent light-receiving regions 53. In this way, the intervals between the light beams incident on the respective light-receiving regions 53 can be made closer. This allows a compact photodetector 50 to be realized. Furthermore, it becomes possible to independently measure the intensities of multiple light beams incident on different regions of the light-receiving surface 52.

[0058] Each light receiving region 53 has a rectangular outer shape on the light receiving surface 52. The shape of the light receiving region 53 is not limited to a rectangle and can be designed appropriately depending on the shape of light incident on the light receiving surface 52. In the example of the photodetector 50 shown in the figure, each light receiving region 53 has a rectangular outer shape. Two of the four sides constituting the rectangle (the shorter sides in the case of a rectangle) are parallel to the first direction. Here, "parallel" includes a difference of ±5 degrees or less.

[0059] The length (Z1, Z2, Z3) of the light-receiving region 53 in the second direction is greater than the length (X1, X2, X3) in the first direction. In the example of the light-emitting device 100 shown in the figure, all the light-receiving regions 53 satisfy this condition. Note that the plurality of light-receiving regions 53 may include a light-receiving region 53 having equal lengths in the first and second directions. Further, the light-receiving regions 53 having a length in the first direction greater than the length in the second direction may be included.

[0060] The plurality of light-receiving regions 53 include two light-receiving regions 53 having different lengths (for example, Z1 < Z2) in the second direction on the light-receiving surface 52. Further, at least one of the light-receiving regions 53 arranged at both ends has a length in the second direction on the light-receiving surface 52 smaller than that of the adjacent light-receiving region 53. Also, the lengths in the second direction of the light-receiving regions 53 arranged at both ends are different (for example, Z1 < Z3).

[0061] By arranging the light-receiving regions 53 with short lengths and long lengths side by side, a space due to the difference in length (for example, Z2 - Z1 > 0) is created on the light-receiving surface 52. By providing a conduction region 55 described later in this space, miniaturization of the photodetector 50 can be achieved. Further, the magnitude of Z2 - Z1 is, for example, 50 μm or more and 150 μm or less, preferably 60 μm or more and 100 μm or less. By setting it within this range, an appropriate-sized light-receiving region 53 can be ensured while using this space for the conduction region 55.

[0062] The plurality of light-receiving regions 53 are arranged with one of the ends at both ends of the light-receiving region 53 in the second direction aligned. In other words, a straight line connecting one of the end points at both ends of each light-receiving region 53 in the second direction is parallel to the first direction. Here, the parallelism includes a difference within ±5 degrees. By aligning the positions of one end, the length of the photodetector 50 in the second direction can be suppressed, contributing to miniaturization.

[0063] Note that the magnitude relationship and arrangement relationship among the plurality of light-receiving regions 53 are not necessarily required for the light-emitting device 100.

[0064] The photodetector 50 has one or more wiring regions 54. The one or more wiring regions 54 may be provided on the light-receiving surface 52. Alternatively, the wiring regions 54 may be provided on a surface other than the light-receiving surface 52. Each wiring region 54 is electrically connected to the light-receiving region 53.

[0065] In the illustrated example of the photodetector 50, a plurality of wiring regions 54 provided on the light-receiving surface 52 realize electrical connection to all of the light-receiving regions 53 arranged on the light-receiving surface 52. Specifically, four wiring regions 54 are provided to electrically connect the three light-receiving regions 53. In other words, the photodetector 50 has more wiring regions 54 on the light-receiving surface 52 than the number of light-receiving regions 53.

[0066] Three of the four wiring regions 54 do not overlap with one another and serve as anode electrodes for any of the three light-receiving regions 53. The remaining one is a cathode electrode common to the three light-receiving regions 53.

[0067] In the example of the photodetector 50 shown in FIG. 9 , an insulating layer 59 having an opening is formed on the upper surface of an n-type semiconductor substrate 58. This opening is provided in the center of a light-receiving surface 52. The region of the light-receiving surface 52 where the opening of the insulating layer 59 is provided is referred to as a central region 56. A wiring region 54 is located on the insulating layer 59 and is insulated from the n-type semiconductor substrate 58. All of the multiple light-receiving regions 53 are arranged in the central region 56. The multiple light-receiving regions 53 may be covered with a protective film. Covering the light-receiving regions 53 with a translucent protective film can protect the light-receiving regions 53 without impeding light detection.

[0068] The multiple wiring regions 54 are provided in edge regions 57, which are regions on the light-receiving surface 52 that extend from the central region 56 in the first direction (FIGS. 8 and 9). Providing the wiring regions 54 in the edge regions 57 can prevent the photodetector 50 from becoming larger in the second direction. The multiple wiring regions 54 are provided in two edge regions 57, one at the end of the center region 56 extending in one first direction (+first direction) and the other at the end of the center region 56 extending in the opposite direction (-first direction). To distinguish between these edge regions 57, they may be referred to as the first edge region 57 and the second edge region 57, respectively. Note that the multiple wiring regions 54 may be provided in only one of the first and second edge regions 57.

[0069] The photodetector 50 has one or more mounting areas 42 on the light-receiving surface 52. The mounting areas 42 are areas used to support other components. The one or more mounting areas are provided outside the central area 56. The one or more mounting areas are provided between the end areas 57 and the central area 56. The one or more mounting areas are provided between the first end area 57 and the second end area 57.

[0070] Furthermore, one or more mounting regions 42 may be provided between the first end region 57 and the central region 56, and one or more mounting regions 42 may be provided between the second end region 57 and the central region 56. In this case, the photodetector 50 will have a plurality of mounting regions 42.

[0071] 8, the one or more mounting areas 42 do not protrude in the second direction further than the light receiving area 53 that is the longest in the second direction among the multiple light receiving areas 53. In other words, the one or more mounting areas 42 are sandwiched between two imaginary straight lines that pass through both ends of the light receiving area 53 in the second direction and extend in the first direction, in a top view. This prevents the photodetector 50 from becoming longer in the second direction, contributing to miniaturization.

[0072] 8, the top surfaces of one or more mounting regions 42 are located higher (above) than the top surfaces of one or more light-receiving regions 53. This allows other components to be bonded in contact with the mounting regions 42, improving the stability of the bond. Also, for example, other components can be mounted on the photodetector 50 while avoiding contact with the light-receiving regions 53.

[0073] Other components can be bonded to one or more mounting areas 42. Each of the one or more mounting areas 42 can be formed, for example, from a metal film or metal bumps disposed on the insulating layer 59. By using the mounting areas 42, other components disposed on the photodetector 50 can be stably supported.

[0074] In the example of the photodetector 50 shown in FIG. 8, the shape of each of the multiple mounting areas 42 is rectangular. The first mounting area 42 and the second mounting area 42 have the same shape. The shape of each mounting area 42 is not limited to a rectangle, and they do not have to be the same shape. The area of ​​the space available as the mounting area 42 between each end area 57 and the central area 56 is, for example, 0.05 mm 2 More than 0.2mm 2 It is in the following range:

[0075] Note that the photodetector 50 may use areas other than the mounting area 42 for bonding to other components. In other words, the areas used to support other components do not have to be limited to one or more mounting areas 42. The mounting area 42 may also be used to play an auxiliary role for stability or ease of mounting.

[0076] The photodetector 50 has one or more conductive regions 55 provided on the light-receiving surface 52. The conductive region 55 is a region that physically and electrically connects the light-receiving region 53 and the wiring region 54. The conductive region 55 electrically connects the light-receiving region 53 and the wiring region 54.

[0077] In the example of the photodetector 50 shown in FIG. 8, each of the plurality of conductive regions 55 is provided in a region between the central region 56 and the end region 57 where no mounting region 42 is provided.

[0078] In the illustrated example of the photodetector 50, a plurality of conductive regions 55 are provided which are connected to all of the light-receiving regions 53 arranged on the light-receiving surface 52. Specifically, there are three conductive regions 55 which are connected to three light-receiving regions 53. In other words, the number of light-receiving regions 53 arranged on the light-receiving surface 52 is equal to the number of conductive regions 55.

[0079] (protective element 60A) The protective element 60A is a circuit element that prevents a specific element (e.g., the light-emitting element 20) from being destroyed by excessive current. A typical example of the protective element 60A is a constant voltage diode such as a Zener diode. A Si diode can be used as the Zener diode.

[0080] (Temperature measuring element 60B) The temperature measuring element 60B is an element used as a temperature sensor for measuring the ambient temperature, and may be, for example, a thermistor.

[0081] (Wiring 70) The wiring 70 is made of a conductor having a linear shape with joints at both ends. In other words, the wiring 70 has joints at both ends of the linear portion for joining to other components. The wiring 70 is, for example, a metal wire. Examples of metals include gold, aluminum, silver, copper, etc.

[0082] (lens member 80) The lens member 80 is formed with one or more lens surfaces. The lens member 80 collimates incident light. For example, the one or more lens surfaces are designed to receive light diverging from a focal position, convert the diverging light into collimated light by refraction, and emit the collimated light from the lens member 80. The lens surfaces are spherical or aspherical. The lens surfaces are formed on the light-incident surface and / or the light-exit surface of the lens member 80. An optical film such as an anti-reflection film or a protective film may be provided on the light-incident surface and / or the light-exit surface of the lens member 80. In the illustrated example of the lens member 80, a concave lens surface is formed on the light-incident surface and a convex lens surface is formed on the light-exit surface. Note that multiple lens surfaces may be formed on the light-incident surface, and the lens member 80 may have one or more lens surfaces on the light-incident surface. Also, multiple lens surfaces may be formed on the light-exit surface, and the lens member 80 may have one or more lens surfaces on the light-exit surface.

[0083] The lens member 80 may be formed from a light-transmitting material, such as glass or plastic. The shape of the light-opaque portion of the lens member 80 is arbitrary, but it preferably has a shape that allows it to be fixed to another component. In the illustrated example of the lens member 80, when the lens member 80 is arranged so that its optical axis extends horizontally, it has a flat lower surface that can function as a bonding surface.

[0084] (Second substrate 90) The second substrate 90 has a plurality of wiring regions 96. In FIG. 4, the wiring regions 96 provided on the second substrate 90 are indicated by hatching. The wiring regions 96 of the second substrate pass through the inside of the second substrate 90 and are electrically connected to wiring regions provided on the lower surface of the second substrate 90. The wiring regions electrically connected to the wiring regions 96 are not limited to the lower surface of the second substrate 90, but may be located on any surface of the second substrate 90. It can be provided on other outer surfaces (top surface and outer surface).

[0085] The second substrate 90 can be formed primarily from ceramic. Examples of ceramics that can be used for the second substrate 90 include aluminum nitride, silicon nitride, aluminum oxide, and silicon carbide.

[0086] The second substrate 90 preferably includes a portion formed from a material with better heat dissipation properties (a material with high thermal conductivity) than ceramic. In the example of the second substrate 90 shown in FIG. 4, the second substrate 90 has a thermally conductive member 97 embedded therein. This thermally conductive member 97 fills an opening that penetrates from the top surface to the bottom surface of the second substrate 90. The thermally conductive member 97 is provided in a region facing the bottom surface of the first substrate 15. The thermally conductive member 97 may be formed from the above-mentioned material with high thermal conductivity. The thermally conductive member 97 may have any shape. In the example of the second substrate 90 shown in FIG. 4, the thermally conductive member 97 is disposed in a central region sandwiched between two groups of wiring regions 96 arranged in an upper and lower area in FIG. 4.

[0087] The second substrate 90 has a structure that supports the components of the light emitting device 100 and can be electrically connected to the electronic components included in these components. The second substrate 90 may also support elements other than the components of the light emitting device 100, such as electronic components or optical components.

[0088] (Light emitting device 100) Next, the light emitting device 100 will be described.

[0089] In the example of the light emitting device 100 described below, one or more light emitting elements 20 are edge-emitting semiconductor laser elements (laser diodes). The plurality of wirings 70 include a plurality of first wirings 71 electrically connected to the light emitting elements 20 and a plurality of second wirings 72 electrically connected to the photodetector 50.

[0090] In the light emitting device 100, one or more light emitting elements 20 are arranged inside the package 10. The one or more light emitting elements 20 are arranged on the mounting surface 11M and surrounded by the sidewall portion 12. Each light emitting element 20 is arranged on the mounting surface 11M via a submount 30. Note that multiple light emitting elements 20 may be arranged on one or more submounts 30. Alternatively, the one or more light emitting elements 20 may be arranged directly on the mounting surface 11M without using a submount 30.

[0091] The one or more light-emitting elements 20 emit light laterally. Furthermore, the one or more light-emitting elements 20 emit divergent light from the light emitting surface 21 toward the outer surface having the light extraction surface 10A among one or more outer surfaces of the package 10. Furthermore, the light traveling along the optical axis emitted from the light emitting surface 21 travels in the second direction. The light traveling along the optical axis emitted from the light emitting surface 21 travels parallel to the mounting surface 11M.

[0092] In the light emitting device 100, the submount 30 is disposed inside the package 10. One bonding surface of the submount 30 is bonded to the light emitting element 20. The other bonding surface on the opposite side is bonded to the mounting surface 11M. The light emitting device 100 may have multiple submounts 30. When the light emitting device 100 has multiple submounts 30, the number of light emitting elements 20 bonded to one submount 30 may be one.

[0093] In the light emitting device 100, the photodetector 50 is disposed inside the package 10. The photodetector 50 is disposed on the mounting surface 11M. The photodetector 50 is surrounded by the sidewall portion 12. The photodetector 50 is disposed directly on the mounting surface 11M. The photodetector 50 may be disposed via a support base or the like instead of being disposed directly on the mounting surface 11M.

[0094] The photodetector 50 is disposed between the light extraction surface 10A and the light emitting element 20 in a top view. The photodetector 50 is also located between the submount 30 and the light extraction surface 10A. The distance between the photodetector 50 and the light emitting element 20 is shorter than the length of the photodetector 50 in the second direction. The distance between the photodetector 50 and the light incident surface of the package 10, onto which light from the light emitting element 20 is incident, is shorter than the length of the photodetector 50 in the second direction. This allows the package 10 to be miniaturized, which can contribute to the miniaturization of the light emitting device 100.

[0095] The photodetector 50 is disposed with its light-receiving surface 52 facing upward. In the illustrated example of the light-emitting device 100, the light-receiving surface 52 is parallel to the mounting surface 11M. Here, "parallel" includes a difference of ±5 degrees or less. Furthermore, the bonding surface 51 of the photodetector 50 is bonded to the mounting surface 11M via a metal layer 17 (FIG. 9).

[0096] In the light emitting device 100, the optical member 40 is disposed inside the package 10. The optical member 40 is disposed above the photodetector 50. The optical member 40 is disposed on the upper surface of the photodetector 50. The optical member 40 is bonded to the photodetector 50. The optical member 40 is mounted so that the lower surface of the optical member 40 faces the light receiving surface 52 of the photodetector 50. The optical member 40 is fixed to the photodetector 50 in a mounting region 42 on the light receiving surface 52.

[0097] The method for fixing the optical member 40 to the photodetector 50 is not limited to this example. For example, the lower surface of the optical member 40 may be bonded to the light receiving surface 52 of the photodetector 50 via a transparent resin layer or adhesive layer. The refractive index of such a resin layer or adhesive layer is approximately the same as the refractive index of air (approximately 100%). 1.0) and is close to the refractive index of glass (for example, 1.5). If the space between the detector 50 and the light receiving surface 52 is filled with a resin layer or adhesive layer, the light reflected by the optical member 40 is less likely to be reflected by the light receiving surface 52 .

[0098] In a configuration in which the optical member 40 is bonded to the light-receiving surface 52 of the photodetector 50 via metal bumps, an anti-reflection film may be deposited on the light-receiving surface 52. Such an anti-reflection film can suppress reflection of light on the light-receiving surface 52 and also protect the light-receiving surface 52.

[0099] Divergent light emitted from one or more light-emitting elements 20 is incident on the optical member 40. Furthermore, the entire main portion of the light emitted from one or more light-emitting elements 20 is incident on the optical member 40. No other optical members such as lenses are arranged on the optical path from the light-emitting surface 21 of the divergent light emitted from one or more light-emitting elements 20 to the optical member 40. The light emitted from the light-emitting elements 20 reaches the optical member 40 without changing its traveling direction. By not interposing any other components, the light emitted from the light-emitting surface 21 can reach the optical member 40 in a short distance. Note that other members may be interposed between the light-emitting surface 21 and the optical member 40.

[0100] The optical member 40 reflects a portion of the incident divergent light and transmits the remaining light. The incident light is separated into transmitted light and reflected light by the partially reflecting surface 41 of the optical member 40. The transmitted light is emitted to the outside of the package 10 from the light extraction surface 10A, and the reflected light is irradiated onto the photodetector 50. In the illustrated example of the light emitting device 100, of the transmitted light and reflected light separated by the optical member 40, the transmitted light is used as main light, and the reflected light is used as monitor light.

[0101] Light emitted from the light emitting element 20 enters from one side of the optical member 40, passes through the partially reflective surface 41, exits from the opposite side, passes through the side wall 12 of the package 10, and is emitted laterally from the light-transmitting region 13. If the number of components arranged on the mounting surface 11M increases, the external dimensions of the package 10 will become larger, but the expansion of the external dimensions can be suppressed more effectively on the side than on the top. If the external dimensions can be made smaller on the side than on the top, the light can be emitted from the side. Therefore, the size of the surface on which the light extraction surface A is provided can be reduced.

[0102] Furthermore, light emitted from the light-emitting element 20 enters one side of the optical member 40, is reflected by the partially reflective surface 41, exits from the lower surface of the optical member 40, and is irradiated onto the light-receiving surface 52 of the photodetector 50. Both the transmitted light and the reflected light are divergent light. The optical member 40 reflects the incident light downward.

[0103] A light receiving surface 52 of the photodetector 50 receives the divergent light reflected by the optical member 40. A light receiving region 53 receives the light reflected by the optical member 40. Of the main portion of the light emitted from the light emitting element 20, all of the light reflected by the optical member 40 is irradiated onto the light receiving region 53.

[0104] The light receiving surface 52 is perpendicular to the light emitting surface 21. However, it does not have to be perpendicular. The light receiving surface 52 is parallel to the mounting surface 11M. However, it does not have to be parallel. Here, perpendicular and parallel include a difference of ±5 degrees or less.

[0105] Furthermore, light-receiving surface 52 is provided at a position lower than the light emission point of light-emitting element 20. In light-emitting device 100, the height from mounting surface 11M to light-receiving surface 52 is lower than the height from mounting surface 11M to light-emitting element 20. This arrangement allows light-receiving region 53 to be provided directly below partially reflecting surface 41, thereby reducing the size of light-emitting device 100 in the second direction.

[0106] Furthermore, when viewed from above, the length of the light-receiving surface 52 in the first direction is greater than the length of the submount 30 in the first direction. Furthermore, when viewed from above, the difference between the length of the light-receiving surface 52 in the first direction and the length of the submount 30 in the first direction is smaller than the length of the submount 30 in the first direction. By satisfying such a relationship, it is possible to prevent the relative size ratio of the photodetector 50 to the submount 30 from becoming too large, which can contribute to the miniaturization of the light-emitting device 100.

[0107] Furthermore, in top view, one or more light receiving regions 53 are arranged within an area sandwiched between two straight lines that are parallel to the second direction and pass through both ends of the submount 30 in the first direction. Furthermore, in top view, one or more wiring regions 54 are arranged outside the area sandwiched between these two straight lines. By satisfying this relationship, the size of the light emitting device 100 in the first direction can be reduced.

[0108] Furthermore, in top view, one or more mounting regions 42 are arranged within an area sandwiched between two straight lines parallel to the second direction and each passing through both ends in the first direction of the submount 30. Furthermore, in top view, one or more mounting regions 42 are arranged outside an area sandwiched between two straight lines parallel to the second direction and each passing through both ends in the first direction of the area where one or more light emitting elements 20 are arranged. By satisfying this relationship, the size of the area of ​​the light receiving surface 52 in the first direction can be reduced.

[0109] The sum of the second direction length of the light emitting element 20 having the longest second direction length and the second direction length of the photodetector 50 is 50% or more of the second direction length of the mounting surface 11M. When the light emitting element 20 is disposed on the mounting surface 11M via the submount 30, the sum of the second direction length of the submount 30 and the second direction length of the photodetector 50 is 50% or more of the second direction length of the mounting surface 11M. Satisfying this relationship can reduce excess internal space in the package 10, which can contribute to miniaturization of the light emitting device 100.

[0110] In the light emitting device 100, one or more protective elements 60A are disposed inside the package 10. One or more protective elements 60A are disposed on the mounting surface 11M. The protective elements 60A are disposed to protect the light emitting elements 20. In the light emitting device 100, one light emitting element 20 That is, the same number of protective elements 60A as the number of light-emitting elements 20 are provided.

[0111] In addition, in top view, one or more protection elements 60A are arranged outside the area sandwiched between two straight lines passing through both ends in the first direction in the area where one or more light emitting elements 20 are arranged. In addition, in top view, one or more protection elements 60A are arranged outside the area sandwiched between two straight lines that are parallel to the second direction and pass through both ends of the submount 30 in the first direction.

[0112] In the light emitting device 100, the temperature measuring element 60B is disposed inside the package 10. The temperature measuring element 60B is disposed on the mounting surface 11M. The temperature measuring element 60B is disposed for the purpose of measuring the temperature of the light emitting element 20.

[0113] Moreover, in top view, the temperature measuring element 60B is arranged outside the area sandwiched between two straight lines passing through both ends in the first direction in the area where one or more light emitting elements 20 are arranged. Moreover, in top view, the temperature measuring element 60B is arranged outside the area sandwiched between two straight lines that are parallel to the second direction and pass through both ends of the submount 30 in the first direction.

[0114] Furthermore, in top view, any straight line that is parallel to the first direction and passes through the photodetector 50 does not pass through the one or more protection elements 60A. Furthermore, in top view, any straight line that is parallel to the first direction and passes through the photodetector 50 does not pass through the temperature measuring element 60B. Because the photodetector 50 is longer in the first direction than the one or more light-emitting elements 20 or the submount 30, arranging the protection element 60A or the temperature measuring element 60B in this relationship can prevent the package 10 from becoming larger in the first direction.

[0115] In the light emitting device 100, the first wiring 71 is joined to the wiring region 14 of the package 10 on the light emitting element 20 side (the side including the surface opposite to the light emitting surface 21 of the light emitting element 20) with a straight line parallel to the light emitting surface 21 of the light emitting element 20 as the boundary in a top view. This makes it easier to prevent the first wiring 71 from entering the optical path of light.

[0116] One end of the second wiring 72 is joined to the wiring region 14. The other end is joined to the wiring region 54 of the photodetector 50. By providing the wiring region 54 in the edge region 57 of the photodetector 50, the distance between the wiring region 14 of the package 10 and the wiring region 54 of the photodetector 50 can be shortened, and the length of the second wiring 72 can be shortened. Furthermore, the height of the second wiring 72 can be reduced, thereby achieving a thin light-emitting device with a reduced height.

[0117] In the light emitting device 100, a plurality of second wirings 72 are bonded to a wiring region 14 on the base 11 and a wiring region 54 on the photodetector 50 within the package 10. In the illustrated example, all wirings (second wirings 72) used for electrical connection of the photodetector 50 are bonded to the wiring region 14 located inside the portion X indicated by the dashed lines in FIGS. 7 and 8. More specifically, the second wirings 72 are bonded to the wiring region 14 of the package 10 on the photodetector 50 side, with a straight line parallel to the light emission surface 21 of the light emitting element 20 as the boundary, in a top view. This makes it easier to prevent the second wirings 72 from entering the optical path of light.

[0118] At least one of the plurality of second wirings 72 is connected to the wiring region 14 of the package 10 in a region sandwiched between a straight line passing through one of the ends of the light receiving surface 52 that is furthest in the second direction in a top view and extending in the first direction, and a straight line passing through the other end and extending in the first direction. It is preferable that the plurality of second wirings 72, or all of the second wirings 72, are connected to the wiring region 14 in this region. By adopting such a configuration, the second wirings 7 It is possible to shorten the length of 2.

[0119] In the light emitting device 100, a sealed closed space is created inside the package 10. Furthermore, by bonding the first substrate 15 and the cap 16 under a predetermined atmosphere, a hermetically sealed closed space is created inside the package 10. By hermetically sealing the space in which the light emitting element 20 is disposed, quality degradation due to dust collection can be suppressed. Note that if the entire light emitting device 100 is used in an environment or atmosphere where there is no need to worry about quality degradation due to the effects of dust collection or moisture in the air, the cap 16 is not necessary. For example, if the entire light emitting device 100 is sealed in an enclosure, there is no need to cover the light emitting element 20, optical member 40, and photodetector 50 with the cap 16.

[0120] In the light emitting device 100, the package 10 is mounted on the second substrate 90. Furthermore, the first substrate 15 of the package 10 is mounted on the second substrate 90. Various electronic components arranged on the mounting surface 11M can be electrically connected to circuits external to the light emitting device 100 via the multiple wiring regions 14 of the first substrate 15 and the multiple wiring regions 96 of the second substrate 90.

[0121] In the light emitting device 100, the lens member 80 is mounted on the second substrate 90. It is to be noted that the lens member 80 is not limited to the second substrate 90. For example, the first substrate 15 of the illustrated light emitting device 100 may be the same size as the second substrate 90, and the lens member 80 may be mounted on the first substrate 15. The lens member 80 is located outside the package 10 and is not surrounded by the side wall portion 12. This allows the size of the package 10 to be reduced.

[0122] In addition, the lower surface of lens member 80 is lower than mounting surface 11M. By bonding the lower surface of lens member 80 to the upper surface of second substrate 90, the lower surface of lens member 80 can be disposed at a position lower than mounting surface 11M. By disposing it in this manner, light emitted from package 10 can be incident on lens member 80 at a position lower than the plane including mounting surface 11M.

[0123] Light emitted from one or more light emitting elements 20 and then emitted from the light-transmitting region 13 to the outside of the package 10 is incident on the lens member 80. The lens member also collimates the incident light and emits it.

[0124] The central axis of the light extracted from the light extraction surface 10A faces in the direction (horizontal direction) in which the mounting surface 11M of the base 11 extends. The optical axis of the lens surface from which light is emitted in the lens member 80 and the central axis of the light extracted from the light extraction surface 10A are at the same height from the mounting surface 11M of the base 11.

[0125] The central axis of the light extracted from the light extraction surface 10A is perpendicular to the light extraction surface 10A. The optical axis of the lens surface from which light is emitted in the lens member 80 is also perpendicular to the light extraction surface 10A. Note that "perpendicular" here includes a difference of ±5 degrees. The central axis of the light does not necessarily have to be perpendicular to the light extraction surface 10A.

[0126] In the illustrated example of the light emitting device 100, a plurality of light emitting elements 20 are disposed inside the package 10. The plurality of light emitting elements 20 are arranged side by side with their light emitting surfaces 21 facing the same direction. The plurality of light emitting elements 20 are also arranged side by side with their light emitting surfaces 21 parallel to each other. Light emitted from each light emitting surface 21 of the plurality of light emitting elements 20 travels toward the side surface of the package 10 having the light extraction surface 10A. The light emitting surfaces 21 of the plurality of light emitting elements 20 do not need to be aligned on the same plane or parallel to each other.

[0127] Also, like the illustrated light emitting device 100, the plurality of light emitting elements 20 are each composed of three semiconductor laser diodes. The three light-emitting elements 20 can be configured with a semiconductor laser element. The three light-emitting elements 20 emit light having mutually different peak wavelengths from the light-emitting surface 21. The three light-emitting elements 20 are a semiconductor laser element that emits blue light, a semiconductor laser element that emits green light, and a semiconductor laser element that emits red light. A configuration in which the three light-emitting elements 20 emit light of three colors, RGB, can be employed, for example, for color image display applications. Note that the colors of light emitted by each light-emitting element 20 are not limited to these, and are not limited to visible light.

[0128] The light receiving surface 52 of the photodetector 50 is provided with at least a plurality of light receiving regions 53 corresponding to the plurality of light emitting elements 20. The number of light receiving regions 53 provided on the light receiving surface 52 is equal to or greater than the number of light emitting elements 20 arranged inside the package 10.

[0129] One light-receiving region 53 is irradiated with light emitted from one light-emitting element 20 and reflected by the optical member 40. Each of the plurality of light-receiving regions 53 is irradiated with light that is reflected by the optical member 40 from a main portion of the light emitted from the corresponding light-emitting element 20. Furthermore, the main portion of the light emitted from one light-emitting element 20 is irradiated only to one light-receiving region 53 among the plurality of light-receiving regions 53. Therefore, the main portion of the light emitted from one light-emitting element 20 is irradiated to one light-receiving region 53 among the plurality of light-receiving regions 53, and is not irradiated to any other light-receiving region 53 among the plurality of light-receiving regions 53. Furthermore, the main portion of the light emitted from one light-emitting element 20 is irradiated to one light-receiving region 53 among the plurality of light-receiving regions 53, and is not irradiated to any other light-receiving region 53 among the plurality of light-receiving regions 53. This allows the intensity of the light emitted from each light-emitting element 20 to be measured. In the illustrated example of the light emitting device 100 , three light receiving regions 53 correspond to three light emitting elements 20 .

[0130] In comparing the light-emitting elements 20 and the photodetector 50, the distance between two adjacent light-emitting elements 20 is shorter than the distance between the two light-receiving regions 53 corresponding to these two light-emitting elements 20. Furthermore, the distance between the two light-receiving regions 53 corresponding to these two light-emitting elements 20 is shorter than the distance between any two light-emitting elements 20 selected from the plurality of light-emitting elements 20 aligned in the first direction. By providing a plurality of light-receiving regions 53 on the light-receiving surface 52 of one photodetector 50, the two light-receiving regions 53 can be arranged at a narrow interval, which can contribute to the miniaturization of the light-emitting device 100.

[0131] Furthermore, light emitted from the plurality of light-emitting elements 20 and emitted from the light-transmitting region 13 to the outside of the package 10 enters the lens member 80 and exits from one lens surface. The light exiting from one lens surface is collimated by the lens member 80. In the illustrated example of the light-emitting device 100, light emitted from three light-emitting elements 20 and emitted from the light-transmitting region 13 to the outside of the package 10 enters the lens member 80, is collimated, and exits from the lens surface. By collimating the light from the plurality of light-emitting elements 20 with one lens surface, the lens member 80 can be made smaller than if a separate lens surface were provided for each light-emitting element 20. This can contribute to the miniaturization of the light-emitting device 100.

[0132] 10 and 11, the relationship between the divergence angle of light emitted from two adjacent light-emitting elements 20 and the distance from the light-emitting elements 20 to the light-receiving surface 52 will be described. 10 and 11 show an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other.

[0133] The divergent light emitted from the light emitting element 20 includes light traveling in a first axis direction (Z axis direction) parallel to the XZ plane. The optical member 40 reflects a portion of this light traveling in the Z axis direction, causing it to travel in a second axis direction (Y axis direction) parallel to the YZ plane (second plane) perpendicular to the XZ plane (first plane). The divergent light that passes through the optical member 40 travels in the Z axis direction. The divergent light that enters the optical member 40 is light that spreads at least in a third axis direction (X axis direction) parallel to the XZ plane (first plane) and perpendicular to the Z axis direction.

[0134] Let L1 be the first optical path length from the light emitting surface 21 of one (first light emitting element) of two adjacent light emitting elements 20 to the light receiving surface 52 of the photodetector 50, θ1 be the half angle of the spread of the main portion of light emitted from the first light emitting element 20 in the third axis direction, and R1 be the radius in the first direction of the irradiation area 22 of the light that is incident on the light receiving surface 52 among the main portion of light emitted from the first light emitting element 20. Note that the light emitted from the light emitting element 20 may also spread in a direction perpendicular to the third axis direction. Furthermore, when the light emitting element 20 is a semiconductor laser element, the irradiation area 22 is defined by the main portion of light among the divergent light emitted from the first light emitting element 20. That is, the irradiation area 22 is defined by the light that is the main portion of light among the divergent light emitted from the first light emitting element 20, and is 1 / e with respect to the peak intensity value in the light intensity distribution of the FFP formed by the light that is incident on the light receiving surface 52. 2 This corresponds to a region having an intensity of 1000 or more.

[0135] Similarly, the second optical path length from the light emitting surface 21 of the other (second light emitting element) of the two adjacent light emitting elements 20 to the light receiving surface 52 of the photodetector 50 is L2, the half angle of spread of the main portion of light emitted from the second light emitting element 20 is θ2, and the radius in the first direction of the irradiation area 22 of the light that is incident on the light receiving surface 52 from the main portion of light emitted from the second light emitting element 20 is R2.

[0136] To narrow the gap between adjacent light-emitting elements 20, it is preferable to set the horizontal divergence angle θ1 to correspond to the horizontal divergence angle rather than the vertical divergence angle. In this case, the outline of the main portion of the light intensity distribution of the FFP on the light-receiving surface 52 is approximated by an ellipse with the first direction as the minor axis and the second direction as the major axis. This ellipse increases in proportion to the optical path lengths L1 and L2 from the light-emitting surface 21 of the light-emitting element 20 to the light-receiving surface 52. Here, the optical path lengths L1 and L2 are optical distances that depend on the refractive index of the medium through which light propagates. For example, if the optical element 40 is made of optical glass with a refractive index of approximately 1.5, the optical distance inside the optical element 40 increases in proportion to the refractive index.

[0137] The radii R1 and R2 of the irradiation areas 22 formed on the light-receiving surface 52 by two adjacent light-emitting elements 20 are L1·tan θ1 and L2·tan θ2, respectively. Therefore, if the center-to-center distance (emitter distance) between two adjacent light-emitting elements 20 is P12, the gap between adjacent irradiation areas 22 on the light-receiving surface 52 is P12-(L1·tan θ1+L2·tan θ2). If the magnitude of P12-(L1·tan θ1+L2·tan θ2) is zero or greater, the adjacent irradiation areas 22 do not overlap on the light-receiving surface 52.

[0138] If the optical path lengths L1 and L2 from the light-emitting surface 21 of the light-emitting element 20 to the light-receiving surface 52 become too large, the magnitude of P12-(L1·tanθ1+L2·tanθ2) will become negative unless the spacing between P12 is increased. In this case, adjacent irradiation areas 22 will overlap on the light-receiving surface 52, and as a result, the photodetector 50 will not be able to obtain individual output signals from adjacent light-emitting elements 20. To independently measure the optical output of the light-emitting element 20 corresponding to each light-receiving area 53 based on the output signals of the photodetector 50 obtained from each light-receiving area 53, it is preferable that the magnitude of P12-(L1·tanθ1+L2·tanθ2) be zero or greater.

[0139] On the other hand, in the example of the light emitting device 100 shown in the figures, divergent light emitted from multiple light emitting elements 20 is collimated by a single lens member 80. For this reason, it is desirable to converge the optical axes of the light emitted from all of the light emitting elements 20 as much as possible to the optical axis of the lens member 80 and pass through the lens surface. In this case, there may be a desire to avoid widening P12 as much as possible.

[0140] If it is desired to narrow the spacing between P12, it is necessary to make (L1·tanθ1+L2·tanθ2) smaller in order to make the magnitude of P12-(L1·tanθ1+L2·tanθ2) equal to or greater than zero. If the light emitting device 100 can be mounted so that the optical path lengths L1 and L2 are short, it is possible to narrow the spacing between P12 while making P12-(L1·tanθ1+L2·tanθ2) equal to or greater than zero.

[0141] In the illustrated example of the light emitting device 100, a gas such as air exists between the light emitting surface 21 of the light emitting element 20 and the optical member 40 (particularly the partially reflective surface 41), but no other members such as a lens or part of the package 10 exist. It is possible to arrange the reflecting surface 41 close to the light emitting surface 21 of the light emitting element 20. By placing the optical member 40 close to the light emitting surface 21 of the light emitting element 20, the light emitted from the light emitting element 20 can be separated into reflected light and transmitted light before it spreads too much.

[0142] According to such a light emitting device 100, before the divergent light emitted from one or more light emitting elements 20 passes through the lens or package, a portion of the divergent light is reflected by the optical element 40 and detected by the photodetector 50, thereby making it possible to shorten the distance that the light emitted from the light emitting surface 21 of the light emitting element 20 travels to reach the light receiving surface 52 of the photodetector 50.

[0143] Furthermore, by shortening the distance, even when a plurality of light-emitting elements 20 are arranged side by side, it becomes possible to shorten the arrangement interval of the light-emitting elements 20 while suppressing overlap of divergent light on the light-receiving surface 52. As a result, it becomes possible to employ a compact optical member 40.

[0144] 10, the height H2 from the mounting surface 11M of the base 11 of the package 10 to the upper surface of the submount 30 is smaller than the height H1 from the mounting surface 11M to the light-receiving surface 52 of the photodetector 50. By reducing the value of H1-H2, the first optical path length L1 and the second optical path length L2 can be shortened.

[0145] When considering reducing the value of H1-H2, it is preferable to also take into consideration the effect of vignetting of transmitted light passing through the optical member 40. For example, it is preferable to avoid vignetting of the main part of the light emitted from the light emitting surface 21 of the light emitting element 20 by the second substrate 90 before it reaches the lens member 80. In this case, in addition to reducing the value of H1-H2, it is effective to ensure a certain level of height for H1.

[0146] The same holds true even if H1 is replaced with the height from the mounting surface 11M to the light emitting point on the light emitting surface 21 of the light emitting element 20. Also, although the relationship between two adjacent light emitting elements 20 has been described in Fig. 11, the same holds true when three or more light emitting elements 20 are arranged side by side.

[0147] 11, the entirety of one irradiation area 22 does not need to fit inside one corresponding light-receiving area 53. A part of one irradiation area 22 may protrude from one corresponding light-receiving area 53. However, it is preferable that the protruding part of the irradiation area 22 is not included in another light-receiving area 53.

[0148] The illumination areas 22 formed by different light-emitting elements 20 may have different shapes and sizes on the same light-receiving surface 52. The shape, size, and position of the light-receiving area 53 can be adjusted depending on the shape, size, and position of the illumination areas 22 formed by the light-emitting elements 20.

[0149] In this embodiment, in the light emitting device 100, the distance from the light emitting surface 21 to the optical member 40 is, for example, 200 μm or less, preferably 150 μm or less, and more preferably approximately 100 μm or less. In addition, the distance from the surface of the optical member 40 from which transmitted light is emitted to the side wall 12 of the package 10 can be, for example, 100 μm or more and 500 μm or less.

[0150] In addition, when the center distance (emitter distance) P12 between the adjacent first and second light-emitting elements is 100 μm or more and 500 μm or less, the first optical path length L1 and the second optical path length L2 are both in the range of 200 μm or more and 1500 μm or less. In this case, for example, the height H1 is 300 μm or more and 600 μm or less, and the height H2 is 100 μm or more and 300 μm or less. In this example, the distance from the light emitting surface 21 of the light emitting element 20 to the lens member 80 can be 1200 μm or more and 5000 μm or less.

[0151] The gap between the two light-receiving regions 53 may be, for example, in the range of 50 μm to 150 μm. The length of each light-receiving region 53 in the first direction may be, for example, in the range of 100 μm to 200 μm. The length of each light-receiving region 53 in the second direction may be, for example, in the range of 250 μm to 500 μm.

[0152] Second Embodiment A light emitting device 200 according to the second embodiment will be described. FIG. 12 is a diagram for explaining an exemplary embodiment of the light emitting device 200.

[0153] The light emitting device 200 includes, as its components, a package 10, one or more light emitting elements 20, a submount 30, an optical element 40, a photodetector 50, a protection element 60A, a temperature measurement element 60B, multiple wirings 70, a lens element 80, and a substrate 90 that supports these components.

[0154] The package 10, one or more light-emitting elements 20, submount 30, photodetector 50, protection element 60A, temperature measurement element 60B, first wiring 71, lens member 80, and substrate 90 are the same as those in the first embodiment and are disclosed in the drawings relating to the first embodiment. The light-emitting device 200 of the second embodiment differs from the light-emitting device 100 of the first embodiment in that the shape of the optical member 40 is different.

[0155] The optical member 40 in the second embodiment has a plate portion having a partially reflective surface 41 on its surface. In the example of the light-emitting device 200 shown in FIG. 12, no transparent material, such as glass, with a refractive index higher than that of air exists between the light-emitting surface 21 of the light-emitting element 20 and the partially reflective surface 41. This effectively shortens the optical path length from the light-emitting surface 21 of the light-emitting element 20 to the light-receiving surface 52 of the photodetector 50. This has the effect of suppressing the expansion of the illuminated area on the light-receiving surface 52.

[0156] As such, the shape of the optical member 40 is not limited to the example shown in the figure and can be various. Any method can be used to fix the plate portion having the partially reflective surface 41 on its surface onto the photodetector 50. For example, support members perpendicular to the plate portion can be fixed to both ends of the plate portion, and these support members can be joined to the mounting area 42 located on the light-receiving surface 52 of the photodetector 50.

[0157] The optical member 40 can also be disposed on the mounting surface 11M of the base 11. However, since it is undesirable for the positional relationship between the optical member 40 and the light receiving surface 52 of the photodetector 50 to vary during manufacturing, it is preferable that the optical member 40 is fixed to the photodetector 50. Before disposing the photodetector 50 on the mounting surface 11M, the photodetector 50 and the optical member 40 may be handled as an integrated component (a "photodetector with a partially reflective surface" or a "photodetector with a beam splitter").

[0158] <Modification> In the first and second embodiments, the photodetector 50 has the configuration described with reference to Figures 8 and 9, for example, but the photodetector 50 is not limited to an element having such a configuration. For example, a modified example in which the conductive region 55 that electrically connects the light-receiving region 53 and the wiring region 54 is modified can be employed.

[0159] Fig. 13 is an enlarged top view of a portion X in a modified example of the photodetector 50. Fig. 14 is a cross-sectional view of the photodetector 50 and its surrounding area taken along the line XIV-XIV in Fig. 13.

[0160] In this modification, the planar layout of the conduction region 55 in top view is the same as the planar layout of the conduction region 55 shown in Fig. 8. The difference is that the conduction region 55 in this modification is made up of an impurity region similar to the light-receiving region 53. Specifically, the conduction region 55 is a p-type impurity region formed in a predetermined position in contact with the upper surface of the n-type semiconductor substrate 58 (light-receiving surface 52 of the photodetector 50).

[0161] In this modification, the conductive region 55 and the mounting region 42 are on different layers, achieving multi-layering. Therefore, the mounting region 42 can be arranged to overlap the conductive region 55. This makes it easy to increase the bonding area between the optical member 40 and the photodetector 50. However, like the light-receiving region 53, the conductive region 55 also generates electron-hole pairs when it receives incident light. Therefore, in this modification, care must be taken to prevent light from entering the conductive region 55, for example, by limiting the light-irradiated region to the inside of the light-receiving region 53.

[0162] In the above-described embodiments and modifications, the optical member 40 is bonded to the light-receiving surface 52 of the photodetector 50, but the method for fixing the optical member 40 to the package 10 is not limited to this example. The optical member 40 may be fixed to the submount 30, or may be bonded directly or indirectly to the top surface or side surface of the cap 16, or the mounting surface 11M of the base 11.

[0163] Although the embodiments of the present invention have been described above, the light-emitting device of the present invention is not strictly limited to the light-emitting device of the embodiments. In other words, the present invention can be realized without being limited to the external shape and structure of the light-emitting device disclosed in the embodiments. For example, a light-emitting device without a protective element may be used. Furthermore, the present invention may be applied without necessarily including all necessary and sufficient components. For example, if the claims do not recite some of the components of a light-emitting device disclosed in the embodiments, the claims allow for the design freedom of those components by those skilled in the art, such as substitution, omission, modification of shape, and change of material, and specify that the invention described in the claims applies. [Industrial Applicability]

[0164] The light emitting device according to each embodiment can be used in head-mounted displays, projectors, lighting, displays, and the like. [Explanation of symbols]

[0165] 10 packages 10A light extraction surface 11 Base 11M mounting surface 11P surrounding area 12 Side wall 13 Translucent area 14 Wiring area 15 board (first board) 16 Cap 17 Metal layer 20 Light-emitting element 30 Submount 40 Optical Components 41 Partially reflective surface 42 Implementation Area 50 Photodetector 51 Joint surface 52 Photosensitive surface 53 Light receiving area 54 Wiring area 55 Conduction area 56 Central area 57 Edge area 58 n-type semiconductor substrate 59 Implementation Area 60A protection element 60B Temperature measuring element 70 Wiring 71 1st wiring 72 2nd wiring 80 Lens components 90 board (second board) 96 Wiring area 97 Thermal Conduction Materials 100 Light emitting device (first embodiment) 200 Light emitting device (second embodiment)

Claims

1. A package having a light extraction surface with a light-transmitting region, the interior of which is a hermetically sealed closed space; a first light-emitting element disposed inside the hermetically sealed closed space of the package and having a first light-emitting surface that emits first light in a first direction; a second light-emitting element disposed inside the hermetically sealed closed space of the package and having a second light-emitting surface that emits second light in the first direction; an optical member that is disposed inside the hermetically sealed closed space of the package, and that reflects a portion of the first light emitted in a first direction from the first light-emitting element and transmits the remaining light, and that reflects a portion of the second light emitted in the first direction from the second light-emitting element and transmits the remaining light; a photodetector disposed within the hermetically sealed closed space of the package, the photodetector including a light receiving surface that receives the first light and the second light reflected via the optical member; and a light emitting device, wherein an optical path length of the first light from the first light emitting surface to the photodetector and an optical path length of the second light from the second light emitting surface to the photodetector are 1.5 mm or less.

2. the package has a base portion including a mounting surface and a sidewall portion including the light extraction surface, the first light-emitting element and the second light-emitting element are disposed on the mounting surface and are surrounded by the sidewall portion, The light emitting device according to claim 1 , wherein light transmitted through the optical member is transmitted through the sidewall portion and emitted laterally from the light-transmitting region of the package.

3. The light emitting device according to claim 2 , wherein the package comprises a first substrate having the base, and a cap having the sidewall and fixed to the first substrate.

4. the photodetector is disposed on the mounting surface, and a height from the mounting surface to the light receiving surface is lower than a height from the mounting surface to the first light emitting element and the second light emitting element; 4. The light emitting device according to claim 2, wherein the optical member reflects downward a portion of the first light emitted from the first light emitting element and a portion of the second light emitted from the second light emitting element.

5. a submount to which the first light emitting element and the second light emitting element are bonded; The light emitting device according to claim 4 , wherein the photodetector is located between the submount and the light extraction surface of the sidewall portion.

6. The light emitting device according to claim 1 , wherein the second light emitting element is arranged alongside the first light emitting element inside the package.

7. the light receiving surface of the photodetector has a first light receiving region and a second light receiving region; a main portion of the light emitted from the light emitting surface of the first light emitting element is irradiated onto the first light receiving region and is not irradiated onto the second light receiving region; The light emitting device according to claim 6 , wherein a major portion of the light emitted from the light emitting surface of the second light emitting element is irradiated onto the second light receiving region and is not irradiated onto the first light receiving region.

8. a third light emitting element disposed next to the first light emitting element and the second light emitting element inside the package and having a light emitting surface that emits third light in the first direction; the optical member receives the light emitted from the third light-emitting element, reflects a portion of the third light emitted from the third light-emitting element, and transmits the remaining light; the light receiving surface of the photodetector receives the third light emitted from the third light emitting element and reflected by the optical member, light emitted from the third light emitting element and transmitted through the optical member is emitted from the light-transmitting region to the outside of the package; The light emitting device according to claim 6 , wherein the first light emitting element, the second light emitting element, and the third light emitting element emit light having mutually different peak wavelengths from the light emitting surface.

9. The light emitting device according to claim 3 , further comprising a second substrate on which the package and the lens member are disposed.

10. The light emitting device according to claim 1 , wherein the first light emitting element is a semiconductor laser element.

11. the first light emitted from the first light-emitting element and the second light emitted from the second light-emitting element each include light traveling in a first axis direction parallel to a first plane, the optical member reflects a portion of the light traveling in the first axis direction, and causes the light to travel in the second axis direction parallel to a second plane perpendicular to the first plane; 11. The light emitting device according to claim 1, wherein the light incident on the optical member is light that spreads at least in a third axis direction that is parallel to the first plane and perpendicular to the first axis direction.

Images