Patent Publication Number: US-2023163562-A1

Title: Light-emitting device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to Japanese Patent Application No. 2021-191615, filed on Nov. 25, 2021, the disclosure of which is hereby incorporated herein by reference in its entirety. 
     BACKGROUND 
     The present disclosure relates to a light-emitting device. 
     Japanese Patent Publication No. H7-161065 discloses an optical pickup device including a semiconductor laser element, a light detection element, and a substrate on which an intermediate electrode is formed. In the optical pickup device of the above-mentioned Japanese Patent Publication, the light detection element for detecting return light is disposed in a position laterally separated from an optical axis of laser light emitted from the semiconductor laser element. 
     SUMMARY 
     A reduction in size of a light-emitting device including a light-emitting element and a photodetector is achieved. 
     In an exemplifying and non-limiting embodiment, a light-emitting device according to the present disclosure includes a base member, a first light-emitting element, a photodetector and one or a plurality of wiring lines. The base member has an upper surface and a first wiring region arranged on the upper surface. The first light-emitting element is disposed on the upper surface of the base member and has a first emission end surface configured to emit light. The photodetector is disposed on the upper surface of the base member and has a light receiving surface configured to receive at least a part of the light emitted from the first emission end surface. The photodetector has a second wiring region. The photodetector is positioned so that an imaginary line perpendicular to the first emission end surface through a first point and an imaginary line perpendicular to the first emission end surface through a second point pass through the photodetector. The first point and the second point are two points at which an imaginary line parallel to the first emission end surface through an inside of an outer edge of the first light-emitting element intersects the outer edge of the first light-emitting element in a top view. At least a part of the first wiring region is arranged in a first region between an imaginary line perpendicular to the first emission end surface through a third point and an imaginary line perpendicular to the first emission end surface through a fourth point. The third point and the fourth point are two points at which an imaginary line parallel to the first emission end surface through an inside of an outer edge of the photodetector intersects the outer edge of the photodetector in the top view. 
     With a light-emitting device according to the present disclosure, a reduction in size of the light-emitting device can be achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a light-emitting device according to a first embodiment. 
         FIG.  2    is a perspective view of the light-emitting device according to the first embodiment excluding a cap of a package. 
         FIG.  3    is a top view of the light-emitting device according to the first embodiment excluding the cap of the package. 
         FIG.  4    is a front view of the light-emitting device according to the first embodiment excluding the cap of the package. 
         FIG.  5    is a diagram for a supplemental description of predetermined points, imaginary lines, regions, and the like in the light-emitting device according to the first embodiment. 
         FIG.  6    is a perspective view of a light-emitting device according to a second embodiment excluding a cap of a package. 
         FIG.  7    is a top view of the light-emitting device according to the second embodiment excluding the cap of the package. 
         FIG.  8    is a diagram for a supplemental description of predetermined points, imaginary lines, regions, and the like in the light-emitting device according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In the present description or the scope of the claims, a polygon such as a triangle and a quadrangle is not limited to a polygon in a mathematically strict sense and also includes a shape in which a corner of the polygon is processed to be rounded, chamfered, beveled, coved, and the like. Furthermore, a shape obtained by processing not only the corner (an end of a side) of the polygon, but also a middle portion of the side is similarly referred to as a polygon. In other words, a shape partially processed while leaving a polygon shape as a base is included in the “polygon” described in the present description and the scope of the claims. 
     The same applies not only to the polygon but also to a word representing a specific shape such as a trapezoid, a circle, a protrusion, and a recession. The same applies when dealing with each side forming that shape. In other words, even when a corner and a middle portion of a certain side are processed, the “side” also includes the processed portion. When the “polygon” or “side” not partially processed is to be distinguished from a processed shape, “strict” will be added to the description as in, for example, a “strict quadrangle”. 
     In the present description or the scope of the claims, when there are a plurality of components identified by a certain term and each of the components is to be expressed separately, an ordinal number such as “first” and “second” may be added in front of each of the terms of the components. For example, when it is described that “two light-emitting elements are disposed on a substrate” in the claims, it may be described that “a first light-emitting element and a second light-emitting element are arrayed on a substrate” in the description. The ordinal numbers of “first” and “second” are used to distinguish the two light-emitting elements. An order of the ordinal numbers has no special meaning. A term of a component provided with the same ordinal number may not refer to the same component between the description and the claims. For example, when components identified by terms of a “first light-emitting element”, a “second light-emitting element”, and a “third light-emitting element” are described in the description, a “first light-emitting element” and a “second light-emitting element” in the claims may correspond to the “first light-emitting element” and the “third light-emitting element” in the description. Furthermore, in claim  1  described in the claims, when the term of the “first light-emitting element” is used and the term of the “second light-emitting element” is not used, the invention according to claim  1  includes at least one light-emitting element. This light-emitting element is not limited to the “first light-emitting element” in the description and can correspond to the “second light-emitting element” or the “third light-emitting element” in the description. 
     In the present description or the claims, terms indicating a specific direction or position (for example, “upper”, “lower”, “right”, “left”, and other terms including those terms) may be used. The terms are merely used to make it easy to understand a relative direction or position in the referenced drawing. As long as the relative direction or position is the same as that described in the referenced drawing using the term such as “upper” or “lower”, in drawings other than the drawings of the present disclosure, actual products, manufacturing devices, and the like, components need not necessarily be arranged in the same manner as in the referenced drawing. 
     A size, a size ratio, a shape, an arrangement interval, and the like of a component or a member illustrated in the drawings may be exaggerated for ease of understanding. Furthermore, in order to avoid excessive complication of the drawings, illustration of some elements may be omitted. 
     Embodiments of the present invention will be described below with reference to the drawings. The embodiments are for embodying the technical concept of the present invention but are not intended to limit the present invention. A numerical value, a shape, a material, a step, an order of the step, and the like indicated in the description of the embodiments are merely one example, and various modifications can be made as long as a technical contradiction does not arise. In the following description, a component identified by the same term and reference sign is the same component or a similar component, and duplicate descriptions of the components may be omitted. 
     First Embodiment 
     A light-emitting device  100  according to a first embodiment will be described with reference to the drawings.  FIGS.  1  to  5    are drawings for illustrating one exemplary form of the light-emitting device  100 .  FIG.  1    is a perspective view of the light-emitting device  100  according to the present embodiment.  FIG.  2    is a perspective view of the light-emitting device  100  in a state where a cap  16  of a package  10  is removed.  FIG.  3    is a top view of the same state as illustrated in  FIG.  2   .  FIG.  4    is a front view of the same state as illustrated in  FIG.  2   .  FIG.  5    is a diagram for a supplemental description of predetermined points, imaginary lines, regions, and the like in the light-emitting device  100  according to the present embodiment. 
     The light-emitting device  100  includes a plurality of components. The plurality of components include the package  10 , one or a plurality of light-emitting elements  20 , a submount  30 , an optical member  40 , a photodetector  50 , a protective element  60 A, a temperature measuring element  60 B, and one or a plurality of wiring lines  70 . 
     First, each of the components will be described. 
     Package  10   
     The package  10  includes a base member  11  including a mounting surface  11 M, and a side wall portion  12  surrounding the mounting surface  11 M. The mounting surface  11 M of the base member  11  is a region in which another component is disposed. Furthermore, the package  10  includes a substrate  15  and the cap  16  fixed to the substrate  15 . The substrate  15  includes the base member  11 , and the cap  16  includes the side wall portion  12 . 
     In a top view, both of outer shapes of the base member  11  and the cap  16  are rectangular. The outer shapes do not need to be rectangular, and may be polygonal other than quadrangular, or a part or the whole of the outer shapes may include a curved line, a bend, or a protrusion and a recession. 
     The base member  11  includes one or more upper surfaces. The one or more upper surfaces included in the base member  11  include the mounting surface  11 M. The one or more upper surfaces included in the base member  11  include a peripheral region  11 P surrounding the mounting surface  11 M. In the illustrated example of the light-emitting device  100 , the mounting surface  11 M and the peripheral region  11 P are located on the same plane. Note that the mounting surface  11 M and the peripheral region  11 P may not be provided on the same plane and may be provided on, for example, different upper surfaces having a height difference. 
     The peripheral region  11 P is a region in which the cap  16  is bonded. In the top view, the peripheral region  11 P is provided between the outer shape of the base member  11  and an outer shape of the mounting surface  11 M. In the example of the light-emitting device  100  illustrated by the drawings, in the top view, the outer shape of the mounting surface  11 M is rectangular, and the peripheral region  11 P is provided around four sides of the rectangle. A lower surface of a side surface portion of the cap  16  is bonded to the upper surface of the peripheral region  11 P. A metal film for bonding to the cap  16  can be disposed in the peripheral region  11 P. 
     The package  10  includes a light-transmissive region  13  being a region having light transmissivity. Further, the package  10  includes a light extraction surface  10 A including the light-transmissive region  13 . The light extraction surface  10 A is included in one surface of one or a plurality of outer side surfaces in the side wall portion  12  of the package  10 . Note that “having light transmissivity” means a property in which a transmittance of main light incident thereon is equal to or more than 80%. For example, provided that infrared light is the main light, “having light transmissivity” holds true when a transmittance for the infrared light is equal to or more than 80%. 
     The whole cap  16  may be formed of a light-transmissive material, or only the side surface portion of the cap  16  may be formed of the light-transmissive material. A part of the cap  16  including the light extraction surface  10 A may be formed of a first light-transmissive material, and a part other than the part of the cap  16  including the light extraction surface  10 A may be formed of a second light-transmissive material or a non-light-transmissive material. 
     The cap  16  can be formed of an upper surface portion and the side surface portion that are integral. For example, the cap  16  having a desired shape such as, for example, a box shape can be manufactured from the light-transmissive material such as glass, plastic, and quartz by using a processing technique such as molding or etching. The cap  16  may be formed by bonding the upper surface portion (a lid portion) and the side surface portion (a frame portion) separately formed of different materials as main materials thereof. For example, the upper surface portion can include monocrystalline silicon or polycrystalline silicon as the main material, and the side surface portion can include glass as the main material. For example, the cap  16  can have dimensions having a height equal to or less than 2.5 mm and having, in the top view, a length of one side equal to or less than 8 mm in an outer shape of a rectangular shape. Furthermore, for example, the cap  16  can have dimensions having a height equal to or less than 2 mm and having, in the top view, a length of one side equal to or less than 4 mm in the outer shape of the rectangular shape. 
     In the example of the light-emitting device  100  illustrated by the drawings, the light extraction surface  10 A is perpendicular to a direction in which the mounting surface  11 M extends. Note that the term “perpendicular” used here allows a difference within ±5 degrees. Furthermore, the light extraction surface  10 A does not need to be perpendicular to the direction in which the mounting surface  11 M of the base member  11  extends and may be inclined. 
     A plurality of wiring regions  14  are provided on the upper surface of the base member  11 . The plurality of wiring regions  14  are provided on the mounting surface  11 M of the base member  11 . In  FIG.  3   , instead of providing a reference sign to all of the wiring regions  14 , similar hatching is applied to all of the wiring regions  14 . The plurality of wiring regions  14  can pass through an interior of the base member  11  and can be electrically connected to a wiring region provided on a lower surface of the base member  11 . The wiring region that is to be electrically connected to the wiring region  14  is not limited to being provided on the lower surface of the base member  11  and can be provided on another external surface (upper surface or outer side surface) of the base member  11 . The plurality of wiring regions  14  can be a film, a layer, or a via that is formed of a conductor such as metal and is patterned. 
     The substrate  15  can be formed of ceramic as the main material. Examples of the ceramic used for the substrate  15  include aluminum nitride, silicon nitride, aluminum oxide, silicon carbide, and the like. 
     In the present embodiment, the substrate  15  can be formed of, for example, a ceramic substrate including a plurality of metal vias therein. The substrate  15  preferably includes a material having heat dissipation (a material having high thermal conductivity) higher than that of ceramic in a portion in thermal contact with a component that generates heat. Examples of such a material may include copper, aluminum, iron, copper molybdenum, copper tungsten, and copper-diamond composite materials. 
     Light-Emitting Element  20   
     The light-emitting element  20  includes an emission end surface  21  that emits light. Examples of the light-emitting element  20  include a semiconductor laser element. The light-emitting element  20  can have an outer shape of the rectangle in the top view. When the light-emitting element  20  is an edge-emitting semiconductor laser element, a side surface intersecting one side of two short sides of the rectangle in the top view is the emission end surface  21  of light. In the example, an upper surface and a lower surface of the light-emitting element  20  have an area greater than that of the emission end surface  21 . The light-emitting element  20  is not limited to an edge-emitting semiconductor laser element and may be a surface-emitting semiconductor laser element, a light-emitting diode (LED), or the like. 
     The light-emitting element  20  is a single emitter including at least one emitter. Note that the light-emitting element  20  may be a multi-emitter including two or more emitters. When the light-emitting element  20  is a semiconductor laser element including a plurality of emitters, one common electrode can be provided on one of the upper surface and the lower surface of the light-emitting element  20 , and two electrodes corresponding to the emitters can be provided on the other of the upper surface and the lower surface. 
     Light emitted from the emission end surface  21  of the light-emitting element  20  is divergent light that spreads. Note that the light may not be the divergent light. When the light-emitting element  20  is a semiconductor laser element, the divergent light (laser light) emitted from the semiconductor laser element forms a far field pattern (hereinafter referred to as an “FFP”) of an elliptical shape on a plane parallel to a light emission surface. The FFP indicates a shape and a light intensity distribution of the emitted light at a position spaced apart from the light emission surface. 
     Light passing through the center of the elliptical shape of the FFP, in other words, light having a peak intensity in the light intensity distribution of the FFP, is referred to as light traveling on an optical axis. Also, the optical path of the light advancing on an optical axis is referred to as the optical axis of the light. Furthermore, based on the light intensity distribution of the FFP, light having an intensity of 1/e 2  or more with respect to a peak intensity value is referred to as light of a “main portion”. 
     In the elliptical shape of the FFP of the light emitted from the light-emitting element  20  being a semiconductor laser element, a minor axis direction of the elliptical shape is referred to as a parallel direction of the FFP, and a major axis direction is referred to as a perpendicular direction of the FFP. A plurality of layers including an active layer constituting the semiconductor laser element are layered in the perpendicular direction of the FFP. 
     Based on the light intensity distribution of the FFP, an angle corresponding to a full width at half maximum of the light intensity distribution is a spread angle of light of the semiconductor laser element. The spread angle of light in the perpendicular direction of the FFP is referred to as a perpendicular spread angle, and the spread angle of light in the parallel direction of the FFP is referred to as a parallel spread angle. 
     As the light-emitting element  20 , for example, a semiconductor laser element that emits blue light, a semiconductor laser element that emits green light, a semiconductor laser element that emits red light, or the like can be employed. A semiconductor laser element that emits light other than blue, green, and red light may also be employed. 
     Blue light refers to light having an emission peak wavelength within a range from 420 nm to 494 nm. Green light refers to light having the emission peak wavelength within a range from 495 nm to 570 nm. Red light refers to light having the emission peak wavelength within a range from 605 nm to 750 nm. 
     Examples of the semiconductor laser element that emits blue light or the semiconductor laser element that emits green light include a semiconductor laser element including a nitride semiconductor. For example, GaN, InGaN, and AlGaN can be used as the nitride semiconductor. Examples of the semiconductor laser element that emits red light include a semiconductor laser element including an InAlGaP-based, GaInP-based, GaAs-based, or AlGaAs-based semiconductor. 
     Submount  30   
     The submount  30  includes two bonding surfaces and is formed in a rectangular parallelepiped shape. One of the bonding surfaces is provided on an opposite side from the other bonding surface. A distance between the two bonding surfaces is less than a distance between other facing two surfaces. A shape of the submount  30  may not be 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 surface. 
     Optical Member  40   
     The optical member  40  includes a partial reflective surface  41 . The partial reflective surface  41  reflects a part of incident light and transmits the remaining light. The light incident on the partial reflective surface  41  is divided into two lights traveling in different directions. The two divided lights include light having the same wavelength. The optical member  40  divides the same wavelength component of the incident light into two at a predetermined ratio. 
     For example, one of the two lights divided by the optical member  40  can be used as primary light (main light), and the other of the two lights can be used as light (monitor light) for monitoring to control the main light. Furthermore, for example, both of the two lights can also be used as the main light. 
     When the incident light is divided into the main light and the monitor light, intensity of the monitor light is less than intensity of the main light. For example, the partial reflective surface  41  transmits 80% or more of the incident light and uses the light as the main light, and reflects 20% or less of the incident light and uses the light as the monitor light. Further, the intensity of the monitor light may be in a range from 5% to 10% of the intensity of the main light. Furthermore, for example, the intensity can be approximately 5% or less than 5%. 
     Reflectance of the partial reflective surface  41  may vary depending on a wavelength of the incident light. Thus, when light of a different color is incident on one partial reflective surface  41 , the reflectance may vary depending on the color. Note that the reflectance does not need to be equal for light of all colors. Design is performed so as to set appropriate reflectance for target light reflected by the partial reflective surface  41 . 
     The partial reflective surface  41  is inclined relative to a lower surface of the optical member  40 . The partial reflective surface  41  is formed of a flat surface having an inclination angle in, for example, a range from 40 degrees to 50 degrees with respect to the lower surface of the optical member  40 . In the illustrated example of the light-emitting device  100 , the partial reflective surface  41  is formed of a flat surface having the inclination angle of 45 degrees with respect to the lower surface. 
     The optical member  40  is formed in a rectangular parallelepiped shape. Note that a shape of the optical member  40  is not limited to the rectangular parallelepiped. Furthermore, the optical member  40  includes an upper surface parallel to the lower surface. A bonding surface for fixing the optical member  40  to another member is preferably included. For example, the lower surface of the optical member  40  can function as the bonding surface. 
     Photodetector  50   
     The photodetector  50  includes a light receiving surface  52 . The photodetector  50  includes an upper surface, a lower surface, and one or a plurality of side surfaces. The light receiving surface  52  is provided on the upper surface of the photodetector  50 . An outer shape of the photodetector  50  is a rectangular parallelepiped. Note that the outer shape may be different from the rectangular parallelepiped. 
     One or a plurality of light receiving regions  53  are provided on the light receiving surface  52 . Each of the one or the plurality of light receiving regions  53  is a photoelectric conversion element that outputs an electrical signal in accordance with an intensity or the amount of light of the incident light. A typical example of such a photoelectric conversion element is a photodiode. 
     The photodetector  50  can be formed of the plurality of light receiving regions  53  including a first light receiving region  53   a  and a second light receiving region  53   b . Furthermore, the photodetector  50  can be formed of the plurality of light receiving regions  53  further including a third light receiving region  53   c . Note that the number of the light receiving regions  53  is not limited to three. 
     The plurality of light receiving regions  53  are disposed side by side at a predetermined interval. Here, a direction in which the plurality of light receiving regions  53  are disposed side by side is referred to as a “first direction”. Furthermore, in the top view, a direction perpendicular to the first direction is referred to as a “second direction”. Furthermore, a direction perpendicular to the first direction and the second direction is referred to as a “third direction”.  1 D in the drawings is an example of the “first direction”, 2D is an example of the “second direction”, and 3D is an example of the “third direction”. 
     The light receiving surface  52  has a rectangular outer shape. Furthermore, the light receiving surface  52  has a length in the first direction greater than a length in the second direction. Note that the length, in the first direction, of the light receiving surface  52  of the photodetector  50  may be the same as or less than the length, in the second direction, of the light receiving surface  52 . 
     The plurality of light receiving regions  53  are disposed side by side at the interval. In other words, in the top view, the light receiving regions  53  are spaced apart from each other, and do not overlap each other. Note that the interval may not be regular. Further, the plurality of light receiving regions  53  are disposed side by side so as to be close to each other. 
     Each of the light receiving regions  53  has a rectangular outer shape on the light receiving surface  52 . The shape of the light receiving region  53  is not limited to the rectangular shape and can be appropriately designed according to a shape of the light incident on the light receiving surface  52 . In the example of the photodetector  50  illustrated by the drawings, each of the light receiving regions  53  has the rectangular outer shape. Two sides (short sides in a case of the rectangle) of four sides constituting the rectangle of the light receiving region  53  are parallel to the first direction. The term “parallel” used here allows a difference within ±5 degrees. 
     The photodetector  50  includes one or a plurality of wiring regions  54 . The one or the plurality of wiring regions  54  are provided on the upper surface of the photodetector  50 . Note that the one or the plurality of wiring regions  54  may be provided on a surface other than the upper surface of the photodetector  50 . Each of the wiring regions  54  is electrically connected to the light receiving region  53 . 
     In the example of the photodetector  50  illustrated by the drawings, electrical connection to all of the light receiving regions  53  disposed on the light receiving surface  52  is achieved by the plurality of wiring regions  54 . Specifically, three of four wiring regions  54  are anode electrodes of any of three light receiving regions  53  without sharing the same anode electrode with each other. The remaining one of the four wiring regions  54  is a cathode electrode common to the three light receiving regions  53 . 
     Protective Element  60 A 
     The protective element  60 A is a circuit element for preventing breakage of a specific element (the light-emitting element  20 , for example) as a result of an excessive current flowing through the element. A typical example of the protective element  60 A is a voltage regulator diode such as a Zener diode. As the Zener diode, an Si diode can be employed. 
     Temperature Measuring Element  60 B 
     The temperature measuring element  60 B is an element used as a temperature sensor for measuring an ambient temperature. For example, a thermistor can be used as the temperature measuring element  60 B. 
     Wiring Line  70   
     The wiring line  70  is formed of a conductor having a linear shape with bonding portions at both ends. In other words, the wiring line  70  includes the bonding portions to be bonded to other components, at both ends of the linear portion. The wiring line  70  is, for example, a metal wire. Examples of the metal include gold, aluminum, silver, copper, or the like. 
     Next, the light-emitting device  100  will be described. 
     Light-Emitting Device  100   
     In an example of the light-emitting device  100  to be described below, the one or the plurality of light-emitting elements  20  are edge-emitting semiconductor laser elements. Furthermore, the plurality of wiring lines  70  include one or a plurality of wiring lines  71  electrically connected to the corresponding light-emitting elements  20 , and one or a plurality of wiring lines  72  electrically connected to the photodetector  50 . In the illustrated light-emitting device  100 , each of wiring lines  72   a ,  72   b ,  72   c , and  72   d  is the wiring line  72  electrically connected to the photodetector  50 . 
     In the light-emitting device  100 , the one or the plurality of light-emitting elements  20  are disposed on the mounting surface  11 M. The one or the plurality of light-emitting elements  20  are surrounded by the side wall portion  12 . Each of the light-emitting elements  20  is disposed on the mounting surface  11 M via the submount  30 . Note that the plurality of light-emitting elements  20  may be disposed on one submount  30 . Furthermore, the one or the plurality of light-emitting elements  20  may be directly disposed on the mounting surface  11 M without the submount  30  interposed therebetween. 
     The one or the plurality of light-emitting elements  20  can include a first light-emitting element  20   a  and a second light-emitting element  20   b . Furthermore, the one or the plurality of light-emitting elements  20  can include a third light-emitting element  20   c . In the top view, the first light-emitting element  20   a  is disposed between the second light-emitting element  20   b  and the third light-emitting element  20   c.    
     Light emitted from the first light-emitting element  20   a  has a peak wavelength different from that of light emitted from the second light-emitting element  20   b . Light emitted from the third light-emitting element  20   c  has a peak wavelength different from those of the light emitted from the first light-emitting element  20   a  and the light emitted from the second light-emitting element  20   b.    
     For example, the first light-emitting element  20   a  is a semiconductor laser element that emits green light. Furthermore, the second light-emitting element  20   b  is a semiconductor laser element that emits red light. Furthermore, the third light-emitting element  20   c  is a semiconductor laser element that emits blue light. Note that a color of the light emitted from each of the light-emitting elements  20  is not limited thereto and is also not limited to visible light. 
     The first light-emitting element  20   a  and the second light-emitting element  20   b  are disposed side by side in the first direction in the top view. An emission end surface  21   a  of the first light-emitting element  20   a  and an emission end surface  21   b  of the second light-emitting element  20   b  are disposed side by side so as to be parallel to each other. The emission end surface  21   a  and the emission end surface  21   b  face the same direction. Note that the emission end surface  21   a  and the emission end surface  21   b  may not be parallel and may not face the same direction. 
     The first light-emitting element  20   a  and the third light-emitting element  20   c  are disposed side by side in the first direction in the top view. The emission end surface  21   a  of the first light-emitting element  20   a  and an emission end surface  21   c  of the third light-emitting element  20   c  are disposed side by side so as to be parallel to each other. The emission end surface  21   a  and the emission end surface  21   c  face the same direction. Note that the emission end surface  21   a  and the emission end surface  21   c  may not be parallel and may not face the same direction. 
     The one or the plurality of light-emitting elements  20  each emit light in a direction from the emission end surface  21  toward the light extraction surface  10 A. The one or the plurality of light-emitting elements  20  each emit the divergent light. The light emitted from the emission end surface  21  and traveling on the optical axis travels in parallel with the mounting surface  11 M. 
     In the light-emitting device  100 , the submount  30  is disposed on the mounting surface  11 M. The submount  30  is bonded to the light-emitting elements  20  on one of the bonding surfaces of the submount  30 . Furthermore, the submount  30  is bonded to the mounting surface  11 M on the other of bonding surfaces of the submount  30  opposite to the one of the bonding surfaces. Note that the light-emitting device  100  may include a plurality of the submounts  30 . 
     In the light-emitting device  100 , the photodetector  50  is disposed on the mounting surface  11 M. The photodetector  50  is surrounded by the side wall portion  12 . The photodetector  50  is disposed between the light extraction surface  10 A and the light-emitting element  20  in the top view. The photodetector  50  is disposed such that the light receiving surface  52  faces upward. In the example of the light-emitting device  100  illustrated by the drawings, the light receiving surface  52  is parallel to the mounting surface  11 M. The term “parallel” used here allows a difference within ±5 degrees. 
     The plurality of wiring regions  14  provided on the upper surface of the base member  11  include the wiring region  14  electrically connected to the light-emitting element  20 , and the wiring region  14  electrically connected to the photodetector  50 . Wiring regions  14   a   1 ,  14   b   1 ,  14   c   1 , and  14   d   1  illustrated in  FIG.  3    are the wiring regions  14  electrically connected to the photodetector  50 . The one or the plurality of wiring regions  14  electrically connected to the photodetector  50  are collectively referred to as a first wiring region below. It can be said that the first wiring region including the plurality of wiring regions  14  spaced apart from each other is provided in the light-emitting device  100 . 
     The photodetector  50  is disposed on an upper surface of the substrate  15  so as to be passed by an imaginary line L 11  perpendicular to the emission end surface  21   a  through one point p 1   a  (one example of the first point) of two points at which an imaginary line L 1  parallel to the emission end surface  21   a  through the inside of an outer edge of the first light-emitting element  20   a  intersects the outer edge of the first light-emitting element  20   a  in the top view. Furthermore, in the top view, the photodetector  50  is disposed on the upper surface of the substrate  15  so as to be passed by an imaginary line L 12  perpendicular to the emission end surface  21   a  through the other point p 2   a  (one example of the second point) of the two points. 
     Furthermore, at least a part of the first wiring region is provided in a region A 1  between an imaginary line L 13  perpendicular to the emission end surface  21  through one point p 3  (one example of the third point) of two points at which an imaginary line L 2  parallel to the emission end surface  21   a  through the inside of an outer edge of the photodetector  50  intersects the outer edge of the photodetector  50  in the top view, and an imaginary line L 14  perpendicular to the emission end surface  21  through the other point p 4  (one example of the fourth point) of the two points. In this way, a size of the light-emitting device  100  can be reduced in the first direction 1D. 
     The photodetector  50  is disposed on the upper surface of the substrate  15  so as to be passed by an imaginary line L 21  or/and L 31 . The imaginary line L 21  or/and L 31  is perpendicular to the emission end surface  21   b  or/and  21   c  through one point p 1   b  or/and plc (examples of the first point) of two points at which the imaginary line L 1  intersects an outer edge of the second light-emitting element  20   b  or/and the third light-emitting element  20   c  in the top view. The imaginary line L 1  is parallel to the emission end surface  21   b  or/and the emission end surface  21   c  and passes through the inside of the outer edge of the second light-emitting element  20   b  or/and the third light-emitting element  20   c . Furthermore, in the top view, the photodetector  50  is disposed on the upper surface of the substrate  15  so as to be passed by an imaginary line L 22  or/and L 32  perpendicular to the emission end surface  21   b  or/and the emission end surface  21   c  through the other point p 2   b  or/and p 2   c  (examples of the second point) of the two points. 
     The photodetector  50  is disposed on the upper surface of the substrate  15  so as to be passed by an imaginary line L 41  perpendicular to the emission end surface  21   a  through one point p 1   d  of two points at which the imaginary line L 1  parallel to the emission end surface  21   a  through the inside of an outer edge of the submount  30  intersects the outer edge of the submount  30  in the top view. Furthermore, in the top view, the photodetector  50  is disposed on the upper surface of the substrate  15  so as to be passed by an imaginary line L 42  perpendicular to the emission end surface  21   a  through the other point p 2   d  of the two points. 
     At least a part of each of the plurality of wiring regions  14  included in the first wiring region is provided in the region A 1 . In the illustrated light-emitting device  100 , at least a part of each of the wiring regions  14   a   1 ,  14   b   1 ,  14   c   1 , and  14   d   1  is provided in the region A 1 . 
     In the top view, the plurality of wiring regions  14  included in the first wiring region include, with the imaginary line L 11  as a boundary, the wiring region  14  provided in a region including the point p 2   a , and the wiring region  14  provided in a region not including the point p 2   a . The plurality of wiring regions  14  are distributed and arranged in the two regions in such a manner, and thus a space of the upper surface of the base member  11  can be effectively used, and a reduction in size of the light-emitting device  100  can be achieved. 
     The first wiring region includes two wiring regions  14  at least a part of which is provided in the region not including the point p 2   a  with the imaginary line L 11  as the boundary. In the light-emitting device  100  illustrated by the drawings, the wiring region  14   a   1  and the wiring region  14   b   1  correspond to the two wiring regions  14 . Further, all of the two wiring regions  14  are provided in the region not including the point p 2   a  with the imaginary line L 11  as the boundary. 
     Furthermore, the first wiring region includes two wiring regions  14  at least a part of which is provided in a region not including the point p 1   a  with the imaginary line L 12  as a boundary. In the light-emitting device  100  illustrated by the drawings, the wiring region  14   c   1  and the wiring region  14   d   1  correspond to the two wiring regions  14 . Furthermore, all of the two wiring regions  14  are provided in the region not including the point p 1   a  with the imaginary line L 12  as the boundary. 
     In the top view, the second light-emitting element  20   b  is disposed in the region not including the point p 2   a  with the imaginary line L 11  as the boundary, and the third light-emitting element  20   c  is disposed in the region not including the point p 1   a  with the imaginary line L 12  as the boundary. The second light-emitting element  20   b  is disposed in a position closer to the wiring region  14  provided in the region not including the point p 2   a  with the imaginary line L 11  as the boundary than the wiring region  14  provided in the region not including the point p 1   a  with the imaginary line L 12  as the boundary. The third light-emitting element  20   c  is disposed in a position closer to the wiring region  14  provided in the region not including the point p 1   a  with the imaginary line L 12  as the boundary than the wiring region  14  provided in the region not including the point p 2   a  with the imaginary line L 11  as the boundary. 
     The plurality of wiring regions  14  included in the first wiring region include two wiring regions  14  spaced apart from each other in a direction perpendicular to the emission end surface  21 . The two wiring regions  14  are disposed side by side in the direction perpendicular to the emission end surface  21 . At least a part of each of the two wiring regions  14  is provided in the region A 1 . In the illustrated light-emitting device  100 , the wiring region  14   a   1  and the wiring region  14   b   1  correspond to the two wiring regions  14 . Furthermore, the wiring region  14   c   1  and the wiring region  14   d   1  also correspond to the two wiring regions  14 . For both of the two wiring regions  14  including the wiring region  14   a   1  and the wiring region  14   b   1 , and the two wiring regions  14  including the wiring region  14   c   1  and the wiring region  14   d   1 , each of the two wiring regions  14  is partially provided in the region A 1 . 
     The region A 1  may be a region between the imaginary line L 13  and the imaginary line L 14 , and between an imaginary line L 3  and an imaginary line L 4  (see  FIG.  5   ). The imaginary line L 3  is parallel to the emission end surface  21   a  through one point p 5  of two points at which an imaginary line L 10  perpendicular to the emission end surface  21   a  through the inside of the outer edge of the first light-emitting element  20   a  intersects the outer edge of the first light-emitting element  20   a  in the top view. The imaginary line L 4  is parallel to the emission end surface  21   a  through the other point p 6  of the two points. The description of the first wiring region described above also applies to this case. 
     The first wiring region is electrically connected to the wiring region  54  of the photodetector  50 . Each of wiring regions  54   a ,  54   b ,  54   c , and  54   d  illustrated in  FIG.  3    is the wiring region  54  electrically connected to the first wiring region. The one or the plurality of wiring regions  54  electrically connected to the first wiring region are collectively referred to as a second wiring region below. It can be said that the photodetector  50  includes the second wiring region including the plurality of wiring regions  54  spaced apart from each other. 
     The plurality of wiring regions  54  included in the second wiring region include the wiring region  54  provided between the imaginary line L 11  and the imaginary line L 13 , and the wiring region  54  provided between the imaginary line L 12  and the imaginary line L 14 . 
     The wiring region  54  provided between the imaginary line L 11  and the imaginary line L 13  can be provided between the imaginary line L 21  and the imaginary line L 13 . Furthermore, this wiring region  54  can be provided between the imaginary line L 41  and the imaginary line L 13 . Furthermore, the imaginary line L 13  passes through the wiring region  14  electrically connected to this wiring region  54 . This wiring region  14  extends further than this wiring region  54  in the first direction  1 D. 
     The wiring region  54  provided between the imaginary line L 12  and the imaginary line L 14  can be provided between the imaginary line L 32  and the imaginary line L 14 . Furthermore, this wiring region  54  can be provided between the imaginary line L 42  and the imaginary line L 14 . Furthermore, the imaginary line L 14  passes through the wiring region  14  electrically connected to this wiring region  54 . This wiring region  14  extends further than this wiring region  54  in the first direction  1 D. 
     Of the plurality of wiring regions  14  provided on the upper surface of the base member  11 , the one or the plurality of wiring regions  14  electrically connected to the light-emitting element  20  are collectively referred to as a third wiring region. It can be said that the third wiring region including the plurality of wiring regions  14  spaced apart from each other is provided in the light-emitting device  100 . 
     A distance from the third wiring region to the photodetector  50  is greater than a distance from the first wiring region to the photodetector  50 . In the top view, the third wiring region is provided in a region not including the photodetector  50  with the imaginary line L 3  parallel to the emission end surface  21  through the emission end surface  21 , as a boundary, and the third wiring region is not provided in a region including the photodetector  50  with the imaginary line L 3  parallel to the emission end surface  21  through the emission end surface  21 , as a boundary. 
     The wiring region  14  included in the first wiring region and the wiring region  14  included in the third wiring region are disposed side by side in the second direction 2D. A length of the first wiring region in the second direction is less than a length of the third wiring region in the second direction. Of the two wiring regions  14  disposed side by side, a length, in the first direction, of the wiring region  14  included in the first wiring region is equal to or less than a length, in the first direction, of the wiring region  14  included in the third wiring region. 
     In the light-emitting device  100 , the protective element  60 A is disposed in the third wiring region. The protective element  60 A is provided to protect the light-emitting element  20 . The protective element  60 A that protects the first light-emitting element  20   a  is disposed across the two wiring regions  14  electrically connected to the first light-emitting element  20   a . The protective element  60 A that protects the second light-emitting element  20   b  is disposed across the two wiring regions  14  electrically connected to the second light-emitting element  20   b . The protective element  60 A that protects the third light-emitting element  20   c  is disposed across the two wiring regions  14  electrically connected to the third light-emitting element  20   c.    
     The length, in the second direction, of the wiring region  14  included in the first wiring region is less than the length, in the second direction, of the wiring region  14  included in the third wiring region. The length, in the second direction, of the wiring region  14  included in the first wiring region is less than that of the wiring region  14  in the third wiring region in which the component such as the protective element  60 A is disposed, and thus a reduction in size of the light-emitting device  100  can be achieved. 
     Of the plurality of wiring regions  14  provided on the upper surface of the base member  11 , the one or the plurality of wiring regions  14  electrically connected to the temperature measuring element  60 B are collectively referred to as a fourth wiring region. It can be said that the fourth wiring region including the plurality of wiring regions  14  spaced apart from each other is provided in the light-emitting device  100 . 
     A distance from the fourth wiring region to the photodetector  50  is greater than the distance from the first wiring region to the photodetector  50 . In the top view, the fourth wiring region is provided in the region not including the photodetector  50  with the imaginary line L 3  parallel to the emission end surface  21  through the emission end surface  21 , as the boundary, and the fourth wiring region is not provided in the region including the photodetector  50  with the imaginary line L 3  parallel to the emission end surface  21  through the emission end surface  21 , as the boundary. 
     In the light-emitting device  100 , the wiring line  71  electrically connects the light-emitting element  20  and the third wiring region. The wiring line  71  is bonded to the third wiring region. The wiring line  72  is bonded to the first wiring region and the second wiring region. One wiring line  72  is bonded to one of the plurality of wiring regions  14  included in the first wiring region and to one of the plurality of wiring regions  14  included in the second wiring region. The light-emitting device  100  includes the same number of the wiring lines  72  as the number of the wiring regions  14  included in the first wiring region. Note that the light-emitting device  100  can also include the number of the wiring lines  72  equal to or greater than the number of the wiring regions  14  included in the first wiring region. 
     In the light-emitting device  100 , the wiring line  72   a  is bonded to one of the two wiring regions  14   a   1  and  14   b   1 , and the wiring line  72   b  is bonded to the other of the two wiring regions  14   a   1  and  14   b   1 . The wiring line  72   a  is bonded to the first wiring region in one region of regions divided into two with the imaginary line L 3  as the boundary in the top view, and the wiring line  72   b  is bonded to the first wiring region in the other region of the regions divided into two. The wiring line  72   a  bonded to the wiring region  14   a   1  that is a wiring region closer to the photodetector  50  among the two wiring regions  14  is bonded to the wiring region  54   a  that is a wiring region farther from the first wiring region among the two wiring regions  54   a  and  54   b.    
     In the light-emitting device  100 , the wiring line  72   c  is bonded to one of the two wiring regions  14   c   1  and  14   d   1 , and the wiring line  72   d  is bonded to the other of the two wiring regions  14   c   1  and  14   d   1 . The wiring line  72   c  is bonded to the first wiring region in one region of the regions divided into two with the imaginary line L 3  as the boundary in the top view, and the wiring line  72   d  is bonded to the first wiring region in the other region of the regions divided into two. The wiring line  72   c  bonded to the wiring region  14   c   1  that is a wiring region closer to the photodetector  50  among the two wiring regions  14  is bonded to the wiring region  54   c  that is a wiring region farther from the first wiring region among the two wiring regions  54   c  and  54   d.    
     A distance, in the first direction  1 D, between a position in which the wiring line  72   a  is bonded to the wiring region  54   a  and a position in which the wiring line  72   b  is bonded to the wiring region  54   b  is less than a distance, in the first direction  1 D, between a position in which the wiring line  72   a  is bonded to the wiring region  14   a   1  and a position in which the wiring line  72   b  is bonded to the wiring region  14   b   1 . In this way, electrical connection can be achieved in the small first wiring region, and a reduction in size of the light-emitting device  100  can be achieved. 
     In the light-emitting device  100 , 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 such that the lower surface of the optical member  40  and the light receiving surface  52  of the photodetector  50  face each other. 
     The optical member  40  is disposed in a position where the imaginary line L 11  and the imaginary line L 12  pass through in the top view. The optical member  40  is disposed in a position where the imaginary line L 21  and the imaginary line L 22  pass through in the top view. The optical member  40  is disposed in a position where the imaginary line L 31  and the imaginary line L 32  path through in the top view. The optical member  40  is disposed in a position where the imaginary line L 41  and the imaginary line L 42  pass through in the top view. The optical member  40  is disposed between the two wiring regions  54  included in the second wiring region in the top view. 
     In the top view, any imaginary line being an imaginary line perpendicular to the emission end surface  21   a  through the optical member  40  does not pass through the wiring region  14  included in the first wiring region. The optical member  40  is disposed in such a manner, and thus the second wiring region can be set closer to the first wiring region, and a reduction in size of the light-emitting device  100  can be achieved. 
     The light emitted from each of the one or the plurality of light-emitting elements  20  is incident on the optical member  40 . The light of the main portion of the light emitted from each of the one or the plurality of light-emitting elements  20  is incident on the optical member  40 . The divergent light emitted from each of the one or the plurality of light-emitting elements  20  is incident on the optical member  40 . 
     The optical member  40  reflects a part of the incident divergent light and transmits the remaining light. The incident light is divided into transmitted light and reflected light by the partial reflective surface  41  of the optical member  40 . The transmitted light is emitted from the light extraction surface  10 A, and the reflected light is applied to the light receiving surface  52  of the photodetector  50 . Of the transmitted light and the reflected light divided by the optical member  40 , the transmitted light can be used as the main light, and the reflected light can be used as the monitor light. 
     The light receiving surface  52  of the photodetector  50  receives at least a part of the light emitted from the emission end surface of the light-emitting element  20 . Note that the photodetector  50  may receive a part of the light emitted from the light-emitting element  20  without passing through the optical member  40  instead of receiving the light optically controlled by the optical member  40 . 
     The first light receiving region  53   a  of the photodetector  50  receives a part of light emitted from the first light-emitting element  20   a . In the top view, the first light receiving region  53   a  is provided so as to be passed by the imaginary line L 11  and the imaginary line L 12 . In the photodetector  50 , only the first light receiving region  53   a  receives the light of the main portion emitted from the first light-emitting element  20   a.    
     The second light receiving region  53   b  of the photodetector  50  receives a part of light emitted from the second light-emitting element  20   b . In the top view, the second light receiving region  53   b  is provided so as to be passed by the imaginary line L 21  and the imaginary line L 22 . In the photodetector  50 , only the second light receiving region  53   b  receives the light of the main portion emitted from the second light-emitting element  20   b.    
     The third light receiving region  53   c  of the photodetector  50  receives a part of light emitted from the third light-emitting element  20   c . In the top view, the third light receiving region  53   c  is provided so as to be passed by the imaginary line L 31  and the imaginary line L 32 . In the photodetector  50 , only the third light receiving region  53   c  receives the light of the main portion emitted from the third light-emitting element  20   c.    
     A length of the submount  30  in a direction parallel to the emission end surface  21   a  of the first light-emitting element  20   a  in the top view is less than the length of the photodetector  50 . Furthermore, a length of the submount  30  in a direction perpendicular to the emission end surface  21   a  of the first light-emitting element  20   a  in the top view is greater than the length of the photodetector  50 . By providing the photodetector  50  having such a shape, the light-emitting device  100  in small size can be achieved. Note that the direction parallel to the emission end surface  21   a  of the first light-emitting element  20   a  can be the same direction as the first direction  1 D. 
     The light receiving surface  52  is provided in a position lower than an emission point of the light of the light-emitting element  20 . With such an arrangement relationship, the light receiving region  53  can be provided directly below the partial reflective surface  41 , and a size of the light-emitting device  100  in the second direction 2D can be suppressed. 
     In the top view, the length of the photodetector  50  in the first direction  1 D is greater than the length of the submount  30  in the first direction  1 D. In the top view, a difference between the length of the photodetector  50  in the first direction  1 D and the length of the submount  30  in the first direction  1 D is less than the length of the submount  30  in the first direction  1 D. By satisfying such a relationship, an increase in a relative size ratio of the photodetector  50  with respect to the submount  30  can be suppressed, and a reduction in size of the light-emitting device  100  can be achieved. 
     In the top view, the one or the plurality of light receiving regions  53  are disposed inside a region sandwiched between two straight lines parallel to the second direction 2D through both ends of the submount  30  in the first direction  1 D. Furthermore, in the top view, the one or the plurality of wiring regions  54  are disposed outside the region sandwiched between the two straight lines. By satisfying such a relationship, a size of the light-emitting device  100  in the first direction can be suppressed. 
     In the light-emitting device  100 , the one or the plurality of light-emitting elements  20  are disposed in a closed space sealed inside the package  10 . By bonding the substrate  15  and the cap  16  together in a predetermined atmosphere, a closed space hermetically sealed inside the package  10  is created. By hermetically sealing the space in which the light-emitting element  20  is disposed, a deterioration in quality due to dust gathering can be suppressed. 
     Second Embodiment 
     A light-emitting device  200  according to a second embodiment will be described.  FIG.  6    is a perspective view of the light-emitting device according to the second embodiment excluding a cap of a package.  FIG.  7    is a top view of the light-emitting device according to the second embodiment excluding the cap of the package.  FIG.  8    is a diagram for a supplemental description of predetermined points, imaginary lines, regions, and the like in the light-emitting device according to the second embodiment. 
     The light-emitting device  200  according to the second embodiment is the same as the light-emitting device  100  according to the first embodiment except that a first wiring region is provided differently. Thus, the description of the light-emitting device  200  other than the way of providing the first wiring region is as described in the first embodiment. Furthermore, in the description of the first embodiment, the description related to the first wiring region other than contents that are not consistent with  FIGS.  7  and  8    also applies to the second embodiment. Wiring regions  14   a   2 ,  14   b   2 ,  14   c   2 , and  14   d   2  illustrated in  FIG.  7    are wiring regions  14  included in the first wiring region of the light-emitting device  200 . 
     In the light-emitting device  200 , the plurality of wiring regions  14  included in the first wiring region include two wiring regions  14  spaced apart from each other in a direction parallel to an emission end surface  21 . The two wiring regions  14  are disposed side by side in the direction parallel to the emission end surface  21 . At least a part of one wiring region  14  of the two wiring regions  14  is provided in a region A 1 . Furthermore, at least a part of the other wiring region  14  of the two wiring regions  14  is provided outside the region A 1 . In the illustrated light-emitting device  200 , the wiring region  14   a   2  and the wiring region  14   b   2  correspond to the two wiring regions  14 . Furthermore, the wiring region  14   c   2  and the wiring region  14   d   2  also correspond to the two wiring regions  14 . For both of the two wiring regions  14  of the wiring region  14   a   2  and the wiring region  14   b   2 , and the two wiring regions  14  of the wiring region  14   c   2  and the wiring region  14   d   2 , all of one wiring region  14  of the two wiring regions  14  is provided between an imaginary line L 13  and an imaginary line L 14 . 
     In the light-emitting device  200 , a length, in a second direction, of the wiring region  14  included in the first wiring region is greater than a length, in the second direction, of the wiring region  14  included in a third wiring region. On the other hand, a length, in a first direction, of the wiring region  14  included in the first wiring region is less than a length, in the first direction, of the wiring region  14  included in the third wiring region. Even when the wiring region  14  included in the first wiring region and the wiring region  14  included in the third wiring region are disposed in such a manner, a reduction in size of the light-emitting device  200  can be achieved. 
     Although the embodiments according to the present invention have been described above, the light-emitting device according to the present invention is not strictly limited to the light-emitting devices of the embodiments. In other words, the present invention can be achieved without being limited to the external shape or structure of the light-emitting device disclosed by each of the embodiments. For example, a light-emitting device that does not include a protective element may be applicable. Furthermore, it can be applied without requiring all the components being sufficiently provided. For example, in a case in which some of the components of the light-emitting device disclosed by the embodiments are not stated in the scope of the claims, the degree of freedom in design by those skilled in the art such as substitutions, omissions, shape modifications, and material changes for those components is allowed, and then the invention stated in the scope of the claims being applied to those components is specified. 
     The light-emitting device according to each of the embodiments can be used for a head-mounted display, a projector, lighting, a display, and the like.