Patent Publication Number: US-11644178-B2

Title: Light emitting device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of U.S. patent application Ser. No. 16/423,153, filed on May 28, 2019, now U.S. Pat. No. 10,851,968. This application claims priority to Japanese Patent Application No. 2018-102074, filed on May 29, 2018. The entire disclosures of U.S. patent application Ser. No. 16/423,153 and Japanese Patent Application No. 2018-102074 are hereby incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to a light emitting device. 
     The use of a lens in collecting, dispersing, or collimating the emitted light from a light emitting element has been known. For example, Japanese Unexamined Patent Publication No. 2010-67380 discloses an automotive light where the emitted light from a light emitting element enters a projection lens by way of a reflector or not by way of the reflector before being externally output. 
     SUMMARY 
     In the case of the light emitting device disclosed in the patent reference mentioned above, however, both the light reflected by the reflector and the light not reflected by the reflector pass through the same lens structure. For this reason, optical output controls, such as collecting, dispersing, and collimating light cannot be applied distinctively to reflected light and non-reflected light. 
     A light emitting device according to the present disclosure includes a base, a first light emitting element, a first light reflecting member, and a lens member. The first light emitting element is disposed on the base and configured to emit light. The first light reflecting member is disposed on the base and having a light reflecting face configured to reflect light. The first light reflecting member is positioned with respect to the first light emitting element so that emitted light from the first light emitting element is divided into a portion of the emitted light from the first light emitting element irradiating onto the light reflecting face and a portion of the emitted light from the first light emitting element traveling outside of the light reflecting face by having an edge of the light reflecting face serve as a boundary. The lens member of which a lowermost face is located upward to the first light emitting element and the first light reflecting member, and configured to control a travelling direction of the emitted light from the first light emitting element. The lens member includes a reflected light passing region and a non-reflected light passing region. The reflected light passing region has a first lens shape configured to control the travelling direction of reflected light, which is the portion of the emitted light reflected by the light reflecting face. The non-reflected light passing region has a second lens shape configured to control a travelling direction of non-reflected light, which is the portion of the emitted light travelling outside the light reflecting face. 
     According to the light emitting device related to the present disclosure, optical output controls, such as collecting, dispersing, and collimating light, can be distinctively performed on reflected light and non-reflected light. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of the light emitting device according to a first embodiment. 
         FIG.  2    is a schematic diagram illustrating the structure of the lens member of the light emitting device. 
         FIG.  3    is a perspective view of the light emitting device without showing the lens member. 
         FIG.  4 A  shows an example of an optical control method based on the lens member. 
         FIG.  4 B  shows another example of an optical control method based on the lens member. 
         FIG.  4 C  shows another example of an optical control method based on the lens member. 
         FIG.  4 D  shows another example of an optical control method based on the lens member. 
         FIG.  5    is a perspective view of a light emitting device according to a second embodiment. 
         FIG.  6    is a top view illustrating how the semiconductor laser elements, etc., are arranged in the light emitting device according to the second embodiment while omitting some elements. 
         FIG.  7    is a top view of the light emitting device according to the second embodiment. 
         FIG.  8    is a cross-sectional view of the light emitting device according to the second embodiment taken along a straight line VIII-VIII in  FIG.  6   . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Certain embodiments of the present disclosure will be explained below with reference to the drawings. The embodiments below, however, are described for the purpose of giving shape to the technical ideas of the present disclosure, and are not intended to require to the present disclosure. In the explanation below, moreover, the same designations and reference numerals show the same members or those similar in character for which explanations will be omitted as appropriate. The sizes of and relative positions of the members in each diagram may be exaggerated for clarity of explanation. 
     First Embodiment 
       FIG.  1    is a schematic diagram of the light emitting device  1  according to a first embodiment. The light emitting device  1  includes a base  10 , at least one submount  20 , at least one semiconductor laser element  30 , at least one light reflecting member  40 , and at least one lens member  50 . In the light emitting device  1 , the submount  20 , the semiconductor laser element  30 , the light reflecting member  40 , and the lens member  50  are arranged on the planar face of the base  10 . Moreover, the component-disposing surface (the planar face in this example) of the base  10  on which the light reflecting member  40  is disposed is used as a reference surface. The lens member  50  is disposed further upwards of the semiconductor laser element  30  and the light reflecting member  40  disposed on the component-disposing surface serving as the reference surface. The constituent elements of the light emitting device  1  will be explained below. The term, “upwards,” in the description herein refers to the direction in which the semiconductor laser element  30  is disposed using the component-disposing surface of the base  10  as a reference. 
     The base  10  has a planar face on which the submount  20  and the light reflecting member  40  directly disposed. The semiconductor laser element  30  is disposed on the planar face of the base member  10  via the submount  20 . In the description herein, the state where a member is directly disposed on a certain face, or placed on another object that is directly disposed on the planar face, will be expressed as “disposing a member on the surface”. In other words, the state where a member is placed on and physically connected to the surface with or without an intermediate therebetween will be described as the member being disposed on the face. The word, “directly”, will be used in the case of specifically noting the state where a member is directly disposed on a surface. If not specifically noted, it means that it may be either. 
     The base  10  has electrodes for electrically connecting the semiconductor laser element  30  to an external power source, and the semiconductor laser element  30  will be electrically connected to the electrodes. The base  10  thus has a function of electrically connecting the semiconductor laser element  30  to an external power source. For the base  10 , a ceramic, metal, composite of these, or the like can be used. 
     The submount  20  has a bottom face to which the base  10  is bonded, and has an upper face on which the semiconductor laser element  30  is disposed. The submount  20  has a function of securing an adequate height from the upper face of the base  10  to the light emission point at which the semiconductor laser element  30  emits light. Accordingly, the submount  20  can be omitted if the semiconductor laser element  30  can secure an adequate height on its own. By using a submount  20  formed of a material having higher thermal conductivity than that of the base  10 , the submount  20  has a function of improving heat dissipation in addition to securing the height. In the light emitting device  1 , the semiconductor laser element  30  has the light emission point on the lateral face that is closer to the light reflecting member  40 , and light is emitted from the light emission point towards the light reflecting member  40 . 
     In the present disclosure, the adequate height to be secured can be defined, for example, as a height which does not allow the main portion of the emitted light from the semiconductor laser element  30  to directly irradiate the base  10 . Using the component-disposing face of the base  10  as a reference, the emitted light from the semiconductor laser element  30  can be segmented into the light travelling towards the component-disposing face, the light travelling in parallel to the component-disposing face, and the light travelling away from the component-disposing face. Accordingly, in this example, the height is secured so that the portion of the main portion of the light that travels towards the component-disposing face does not directly irradiate the component-disposing face, but instead irradiates the light reflecting member  40 . For this purpose, the height to be secured is determined by taking into consideration the spread of the emitted light from the semiconductor laser element  30 , the distance between the semiconductor laser element  30  and the light reflecting member  40  disposed on the component-disposing face, and the like. In the present disclosure, the main portion of the light from a laser element refers to the portion having an intensity in the range of from the laser beam&#39;s peak intensity value to a given intensity, such as 1/e 2 . 
     For the submount  20 , one that suitably adheres the base  10  to the semiconductor laser element  30  is preferable. In the case of using a material containing nitride semiconductors for the semiconductor laser element  30  and an aluminum nitride as a base material for the base  10 , for example, an aluminum nitride or silicon carbide can be used for the submount  20 . A metal film is disposed on the submount  20 , and the semiconductor laser element  30  is secured to the submount  20  using a conductive layer such as Au—Sn. 
     The bottom face of the semiconductor laser element  30  is bonded to the submount  20 , and the semiconductor laser element emits light from the lateral face that is closer to the light reflecting member  40 . The emitted light from the semiconductor laser element  30  has an elliptical far field pattern (hereinafter referred to as “FFP”) where the length in the stacking direction of multiple semiconductor layers, including an active layer, is larger than the length in the direction perpendicular to the stacking direction in a plane parallel to the light emitting end face. An FFP in the present disclosure is a luminous intensity distribution of the emitted light measured at a plane that is at a certain distance from and in parallel to the light emitting end face of the semiconductor laser element. The shape of an FFP is identified as the shape of the main portion of light. 
     The bottom face of the light reflecting member  40  is bonded to the base  10 , and the light reflecting member  40  reflects the emitted light from the semiconductor laser element  30 . The light reflected by the light reflecting member  40  travels towards the lens member  50  located upwards thereof. The optical path length of the emitted light from the semiconductor laser element  30  to the lens member  50  tends to be larger when the light travels by way of the light reflecting member  40  than in the case of not by way of the light reflecting member  40 . A longer optical path length can reduce the impact of a misalignment between the light reflecting member  40  and the semiconductor laser element  30 . 
     The light reflecting member  40  has a light reflecting face on at least one face. The light reflecting member  40  receives the light from the semiconductor laser element  30  thus it is preferable to use a highly heat resistant material as a main material for the light reflecting member, and a material having high reflectance for the light reflecting face. The base material of the light reflecting member  40  may be formed of a glass material such as quartz, BK7 (borosilicate glass), a metal such as aluminum, or Si or the like. The reflecting face of the light reflecting member  40  may be formed of a metal or dielectric multilayer. The light emitting device  1  may include a light reflecting member  40  having multiple light reflecting faces or another light reflecting member in addition to the light reflecting member  40 , as needed. 
     The lens member  50  is disposed in the position where the emitted light from the semiconductor laser element  30  enters. The light entering the lens member  50  includes the light entering after being reflected by the light reflecting member  40 , and the light entering after travelling upwards of the light reflecting member  40  without being reflected by the light reflecting member  40 . To simplify the description, the light entering after being reflected by the light reflecting member  40  will be hereinafter referred to as “reflected light”, and the light entering after travelling above the light reflecting member  40  without being reflected by the light reflecting member  40  will be referred to as “non-reflected light”. For the lens member  50 , for example, a glass material such as BK7 and B270 can be used. 
       FIG.  2    is a schematic diagram explaining the structure of the lens member in the light emitting device  1  according to the first embodiment of the present disclosure.  FIG.  3    is a perspective view of the light emitting device  1  to illustrate the emitted light from the semiconductor laser element  30  according to the first embodiment. The lens member  50  is not shown in  FIG.  3    for clarity of explanation. 
     As shown in  FIG.  2   , the lens member  50  of the light emitting device  1  includes a reflected light passing region having a first lens shape  51  and a non-reflected light passing region having a second lens shape  52 . The first lens shape  51  has a lens shape designed to control the portion of the emitted light from the semiconductor laser element  30  that is reflected light. On the other hand, the second lens shape  52  has a lens shape designed to control the non-reflected light. Specifically, in the light emitting device  1  according to the first embodiment, the lens shape of the first lens shape  51  is designed based on the focal point FR of the reflected light and the lens shape of the second lens shape  52  is designed based on the focal point FD of the non-reflected light. The optical controls using the lens member  50  include, for example, collecting, dispersing, and collimating light. 
     The solid arrowed lines in  FIG.  2    and  FIG.  3    indicate the travelling directions of the light L emitted from the semiconductor laser element  30 . The broken line in  FIG.  3    indicates the irradiation region where the main portion of the emitted light from the semiconductor laser element  30  irradiates the plane where the light reflecting face  41  of the light reflecting member  40  is present. 
     The semiconductor laser element  30  emits light having an elliptical FFP. The beam divergence is larger in the vertical direction than the lateral direction. The irradiation region has the shape attributable to this. As shown in  FIG.  3   , in the light emitting device  1 , a portion of the irradiation region is not contained in the light reflecting face  41  of the light reflecting member  40 . This portion of light does not irradiate the light reflecting face  41 , but passes upwards of that. The portion of the emitted light from the semiconductor laser element  30  that irradiates and is reflected by the light reflecting face  41  constitutes reflected light, and the light that does not irradiate the light reflecting face  41  and travels upwards of the light reflecting face  41  constitutes non-reflected light. 
     Among the points LU and LD located at two opposing ends of the vertical beam spread, the point LD is preferably present in the light reflecting face  41 . Specifically, a lower end of a vertical divergence of the main portion of the emitted light from the semiconductor laser element  30  is present in the light reflecting face  41  of the light reflecting member  40 . In this case, the portion of the light travelling towards the edge of the vertical beam spread that travels away from the component-disposing face of the base  10  is non-reflected light passing outside the light reflecting member  40 , and that travelling towards the component-disposing face of the base  10  is reflected light which irradiates and is reflected by the light reflecting face  41 . The upper edge of the light reflecting face  41  can be understood as the boundary between reflected light and non-reflected light. In other word, the light reflecting member  40  is positioned with respect to the semiconductor laser element  30  so that emitted light from the semiconductor laser element  30  is divided into a portion of the emitted light from the semiconductor laser element  30  irradiating onto the light reflecting face  41  and a portion of the emitted light from the semiconductor laser element  30  traveling outside of the light reflecting face  41  by having the edge of the light reflecting face  41  serve as the boundary. 
     As shown in  FIG.  2   , the first lens shape  51  is for controlling the output direction of the reflected light travelling upwards by way of the light reflecting member  40 , thus it is designed so that the light reflected at the boundary passes through the first lens shape  51  before externally output from the lens member  50 . The first lens shape  51  is also designed so that the main portion of the light reflected at a location close to the lower edge of the light reflecting face  41  also passes through the first lens shape  51  before externally output from the lens member  50 . 
     In the case where the light irradiating the point LD (in  FIG.  3   ) and reflected irradiates the semiconductor laser element  30  or the submount  20  and not entering the lens member  50 , the light reflected at a position near the lower edge of the light reflecting face  41  includes light that does not enter the lens member  50 . The materials composing and the size of the semiconductor laser element  30 , the laser beam divergence angle, the angle of the light reflecting face  41  of the light reflecting member  40 , and the like affect whether the main portion of the light includes such light. 
     If the light reflected at the point LD enters the lens member, the lens member  50  can simply be designed so that the light reflected at the point LD passes through the first lens shape. If not, on the other hand, the first lens shape  51  can simply be provided on the extension of the travelling direction of the portion of the light reflected near the lower edge of the light reflecting member  41  that travels towards the upper edge UE of the semiconductor laser element  30  as shown in  FIG.  2   . The upper edge UE is a boundary between the reflected light directly travelling toward the incident face of the lens member  50  and the reflected light being incident on other member. The aforementioned “other member” refers the member(s) positioned between the component-disposing face of the base  10  and the incident face of the lens member  50 . 
     The second lens shape  52  can conceivably be designed so that the portion of the emitted light from the semiconductor laser element  30  that is emitted most upwards passes through the second lens shape  52  before being externally output from the lens member  50 . The lens member  50  may be designed so that the straight line connecting the light emission point FD of the semiconductor laser element  30  and the upper edge boundary of the light reflecting face  41  passes through the second lens shape  52 . Thus, the light travelling outside the light reflecting face  41 , in other words, the entire non-reflected light passing upwards of the boundary of the light reflecting face  41  can be output from the second lens shape  52  in  FIG.  2   . 
     The boundary between the first lens shape  51  and the second lens shape  52  is located at the intersection point CP of the upper most light path of the non-reflected light and the path of light reflected at the boundary of the light reflecting face  41 . This can avoid the situation where the reflected light passes through the second lens shape  52  and the non-reflected light passes through the first lens shape  51 . Considering the manufacturing tolerance of the light emitting device  1 , however, it is desirable to set the boundary DP between the first lens shape  51  and the second lens shape  52  at a position farther from the intersection point CP as shown in  FIG.  2   . Specifically, the boundary DP may be set at a position that is farther from the intersection point CP using the focal point FD or FR as a reference in the region interposed between the upper most part of the light path from the semiconductor laser element  50  and the path of light reflected at the boundary of the light reflecting face  41  which is the region where, theoretically, neither reflected light nor non-reflected light passes through. 
     On the other hand, setting the DP in this manner increases the vertical beam divergence, resulting in increase of the size of the light emitting device  1 . This is because the intersection point CP will be positioned more upwards, which proportionally positions the DP more upwards to thereby increase the height of the light emitting device  1  as a whole. Accordingly, in order to reduce the size of the light emitting device  1 , the boundary DP may be positioned at a closer position than the CP. Such a case gives rise to a region where both reflected light and non-reflected light are output from the spherical surface of the lens member  50 . In this case, it is preferable to make this region the first lens shape  51  by prioritizing the reflected light. Because the intensity of reflected light is higher, prioritizing the reflected light increases the total amount of light that is controlled and output. At any rate, the lens member  50  is preferably designed by taking into consideration the manufacturing tolerance so that the light reflected at the upper edge of the light reflecting face  41  passes through the first lens shape  51 , and is preferably designed so that the entire reflected light in the main portion of the light passes through the first lens shape  51 . 
     In  FIG.  2   , the device is designed so that the travelling direction OA which is the direction of the portion of the emitted light from the semiconductor laser element  30  that travels perpendicularly to the emission end face is in parallel to the bonding face between the base  10  and the light reflecting member  40 , but this being in parallel is not necessarily required. The present disclosure is applicable to a light emitting device requiring or not requiring the direction being in parallel. 
       FIGS.  4 A to  4 D  show examples of how the lens member  50  controls light.  FIG.  4 A  shows an optical control such that both reflected light and non-reflected light are collimated in the same direction. In this case, the first lens shape  51  and the second lens shape  52  have the shapes to function as collimating lenses for collimating reflected light and non-reflected light, respectively. The first lens shape  51  is designed so as to collimate the light from the focal point FR to a given direction, and the second lens shape  52  is designed so as to collimate the light from the focal point FD into the same direction as that being controlled by the first lens shape  51 . In this manner, in the case where a portion of the emitted light from the semiconductor laser element  30  is non-reflected light, for example, the device can output collimated light having a larger amount of light than in the case of only utilizing reflected light. 
       FIG.  4 B  shows a case where reflected light and non-reflected light are collimated in different directions. Accordingly, the first lens shape  51  and the second lens shape  52  are designed so that the light will respectively be collimated in given directions using as reference the focal points FR and FD. In this manner, for example, by adjusting the percentages of reflected light and non-reflected light, the emitted light from a single semiconductor laser element  30  can be separated into two to be each utilized as collimated light. Moreover, for example, the travelling direction of non-reflected light can be controlled so as not to interfere with the irradiation region of the collimated reflected light. 
       FIG.  4 C  shows an optical control where reflected light and non-reflected light are collected to the same point. In this case, the first lens shape  51  and the second lens shape  52  are designed so that reflected light and non-reflected light are collected at the same point. In this manner, in the case where a portion of the emitted light from the semiconductor laser element  30  is non-reflected light, for example, a larger amount of light can be collected than in the case of utilizing only reflected light. 
       FIG.  4 D  shows an optical control that collects reflected light and non-reflected light at different points, and the first lens shape  51  and the second lens shape  52  are designed in accordance with the points at which each light is collected. In this manner, for example, by adjusting the percentages of reflected light and non-reflected light, the emitted light from a single semiconductor laser element  30  can be separated into two to be each collected at a specific position. The light control may be performed other methods without any limitation to those that have been described above. The shapes of the first lens shape  51  and the second lens shape  52  can simply be designed in accordance with a desired manner in which reflected light and non-reflected light are to be controlled. 
     As explained above, the light emitting device  1  according to the first embodiment can achieve light output controls tailored to both portions of the emitted light from the semiconductor laser element  30  that are reflected light and non-reflected light. 
     Second Embodiment 
     A light emitting device  2  according to a second embodiment externally outputs the emitted light from multiple semiconductor laser elements through the lens member. The light emitting device  2  according to the second embodiment, moreover, has a package having the function of outputting controlled light, and a mounting substrate. The mounting substrate does not have to be included.  FIG.  5    to  FIG.  8    are diagrams illustrating the light emitting device  2 .  FIG.  5    is a perspective view of the light emitting device  2 .  FIG.  6    is a top view showing the constituent elements arranged in the frame of the base  210  of the light emitting device  2 .  FIG.  7    is a top view of the light emitting device  2 .  FIG.  8    is a cross-sectional view of the light emitting device taken along line VIII-VIII in  FIG.  7   . For clarity of explanation,  FIG.  6    shows the state where the cover  260  bonded to the base  210  is omitted from the light emitting device  2 . In  FIG.  5    to  FIG.  8   , dotted lines S1 and S2 are supplemental lines to indicate how the orientation of the light emitting device  2  correspond among the drawings, and are not constituent elements of the light emitting device  2 . 
     As shown in  FIG.  5   , the light emitting device  2  has a substrate  200  serving as a mounting substrate, a base  210  serving as a package, a cover  260 , a bonding part  270 , and a lens member  250 . The base  210  has a recessed shape as a whole, and as shown in  FIG.  6   , multiple semiconductor laser elements, submounts respectively corresponding to the semiconductor laser elements, and multiple light reflecting members are arranged in the framed area surrounded by the lateral portions of the base  210 . 
     Specifically, on the planar face in the frame of the base  210 , a first semiconductor laser element  230 , a second semiconductor laser element  231 , a third semiconductor laser element  232 , a first submount  220  on which the first semiconductor laser element  230  is disposed, a second submount  221  on which the second semiconductor laser element  231  is disposed, a third submount  222  on which the third semiconductor laser element  232  is disposed, a first light reflecting member  240  corresponding to the first semiconductor laser element  230 , a second light reflecting member  241  corresponding to the second semiconductor laser element  231 , and a third light reflecting member  242  corresponding to the third semiconductor laser element  232  are disposed. The constituent elements of the light emitting device  2  will be explained below. 
     The substrate  200  is bonded to the base  210  and has a function of electrically connecting the semiconductor laser elements disposed on the planar face of the base  210 . The multiple metal films  280  shown in  FIG.  7    are for that purpose. On the upper face of the substrate  200 , three pairs of metal film  280  are disposed respectively corresponding to the semiconductor laser elements. Each metal film  280  has an insulating film-covered region  282 , while regions  281  and  283  of the metal film are not covered. The insulating film  282  can reduce the spreading of solder onto the metal film region  281  when the base  210  is soldered to the substrate  200 . The substrate  200  can be formed using a combination of an insulating material, such as a ceramic, and a conductive material, such as a metal. 
     The base  210 , as shown in  FIG.  8   , has a bottom part and lateral parts, and the recess is defined by the upper face  213  of the bottom part and the inner lateral faces of the lateral parts. The outer lateral faces of the lateral parts meet the lower face of the bottom part, and the bottom faces of the lateral parts are also configured as parts of the lower face of the bottom part. The upper faces  211  of the lateral parts of the base  210  are bonded to the cover  260 , and the lower face of the bottom part is bonded to the substrate  200 . As shown in  FIG.  6   , multiple light reflecting members and the submounts respectively corresponding to the semiconductor laser elements are directly disposed on the upper face  213  of the bottom part. Similar to the first embodiment, the submounts may be omitted where the semiconductor laser elements are disposed directly on the upper face of the bottom part. The lower face of the bottom part can be considered as the bonding face with the substrate  200 . The upper face of the bottom part can be considered as the surface on which the semiconductor laser elements, light reflecting members, and/or submounts are disposed. The upper faces of the lateral parts can be considered as the bonding faces with the cover  260 . 
     As shown in  FIGS.  6  and  8   , the base  210  has one or more stepped portions inside the recess at some of the lateral parts. In the example shown in  FIG.  6   , the one or more stepped portions are provided on the inner sides of the lateral parts excluding one on the S1 side. A metal film for electrically connecting with the substrate  200  is formed on the planar faces  212  formed by the stepped portions, in other words, the planar faces  212  formed between the inner lateral faces meeting the upper face  213  of the bottom part of the base  210  and the inner lateral faces of the lateral parts meeting the upper faces  211  of the lateral parts of the base  210 . Each semiconductor laser element can receive the supply of power from the outside of the light emitting device  2  by electrically connecting the metal film using wires. 
     The cover  260  is bonded to the base  210  to thereby cover the framed area surrounded by the lateral parts of the base  210 . A metal film is disposed in the area of the lower face of the cover  260  to be bonded to the base  210 , and the base  210  and the cover  260  are bonded and fixed via AuSn or the like. The closed space formed by bonding the base  210  and the cover  260  together is a sealed space. Disposing semiconductor laser elements in this closed space can reduce dust, such as organic substances and like, from adhering to the emission end faces of the semiconductor laser elements. For the cover  260 , glass with a metal film disposed thereon, or sapphire with a metal film disposed thereon can be used, for example. Among them, sapphire with a metal film disposed thereon is preferable. When light spreads, the shape of a lens part through which the light passes is needed to increases in size. Sapphire which has a relatively high refractive index can reduce the spreading of light, thereby maintaining the size of the lens part of the lens member  250  under control. Moreover, because sapphire has relatively high strength and is not susceptible to damage, the reliability of the hermetic seal can be ensured for the closed space. 
     The bonding part  270  is formed by the adhesive that bonds the cover  260  and the lens member  250 . The bonding part  270  adheres to the upper face of the cover  260  and the lower face of the lens member  250  thereby fixing the cover  260  and the lens member  250 . The bonding part  270  is not formed across the entire upper face of the cover  260  or the entire lower face of the lens member  250 , and is disposed so as not to interfere with the paths of light emitted from the semiconductor laser elements. For this purpose, the bonding member  270  is preferably formed by not forming it in the areas of the lower face of the lens member  250  that correspond to the regions where the first lens part  253 , the second lens part  254 , and the third lens part  255  are formed, but instead by forming it in the outer peripheral region of the lens member  250 . For the adhesive that forms the bonding part  270 , a UV curable resin is preferably used. A UV curable resin may be cured in a relatively short period of time without involving heat, thus it can readily secure the lens member  250  at a desired position. 
     The lens member  250  has a lens shape where multiple lens parts are linked. Specifically, a first lens part  253 , a second lens part  254 , and a third lens part  255  are linked, lens parts allowing light from semiconductor laser elements to respectively pass through. The first lens part  253  has a first lens shape  251  and a second lens shape  252 . The first lens shape  251  (the reflected light passing region) and the second lens shape  252  (the non-reflected light passing region) of the first lens part  253  are linked to the first lens shape  251  (the reflected light passing region) of the second lens part  254 . The first lens shape  251  and the second lens shape  252  are the same as or similar to the first lens shape  51  and the second lens shape  52  explained with reference to the first embodiment. 
     The light emitting device  2  according to the second embodiment includes three semiconductor laser elements where red light L 1  emitted by the first semiconductor laser element  230  passes through the first lens part  253 , blue light L 2  emitted by the second semiconductor laser element  231  passes through the second lens part  254 , and green light L 3  emitted by the third semiconductor laser element  232  passes through the third lens part  255 . The first lens shape  251  of the first lens part  253  is designed to collimate reflected red light, and the second lens shape  252  of the first lens part  253  is designed to collimate non-reflected red light. The second lens part  254  is designed to have a lens shape to collimate reflected blue light, and the third lens part  255  is designed to have a lens shape to collimate reflected green light. 
     The peak emission wavelength of blue light is preferably in the range of from 420 nm to 494 nm, more preferably in the range of from 440 nm to 475 nm. Examples of blue light emitting semiconductor laser elements include semiconductor laser elements which include nitride semiconductors. Examples of nitride semiconductors include GaN, InGaN, or AlGaN. 
     The peak emission wavelength of green light is preferably in the range of from 495 nm to 570 nm, more preferably in the range of from 510 nm to 550 nm. Examples of green light emitting semiconductor laser elements include semiconductor laser elements which include nitride semiconductors. Examples of nitride semiconductors include GaN, InGaN, or AlGaN. 
     The peak emission wavelength of red light is preferably in the range of from 605 nm to 750 nm, more preferably in the range of from 610 nm to 700 nm. Examples of red light emitting semiconductor laser elements include those including an InAlGaP-based, GaInP-based, GaAs-based, or AlGaAs-based semiconductor. In the present embodiment, a red light emitting semiconductor laser element equipped with two or more waveguide regions is used. Semiconductor laser elements including these semiconductors is likely to reduce output due to heat as compared to semiconductor laser elements including nitride semiconductors. Accordingly, increasing the waveguide regions can disperse heat thereby attenuating the output decline in the semiconductor laser element. 
     The light emitting device  2  can have a different color combination besides employing semiconductor laser elements in three colors of red, blue, and green. As described above, red light has inferior output characteristics attributable to heat as compared to others, and blue light generates less heat than green light. The green light emitting semiconductor laser element  231  among the three semiconductor laser elements is positioned in the middle of the light emitting device  2  because the semiconductor laser element  231  has the best thermal characteristics among these three. In other words, even in the case of employing semiconductor laser elements other than red, blue and green, it is preferable to dispose the semiconductor laser element having the best thermal characteristics among three in the middle. 
     A light reflecting member is provided per semiconductor laser element. A first light reflecting member  240  corresponding to the first semiconductor laser element  230 , a second light reflecting member  241  corresponding to the second semiconductor laser element  231 , and a third light reflecting member  242  corresponding to the third semiconductor laser element  232  are disposed on the planar face of the base  210 . 
     In the frame of the base  210 , the first semiconductor laser element  230 , the second semiconductor laser element  231 , and the third semiconductor laser element  232  are disposed so that the emission end faces of the three semiconductor laser elements are aligned. That is, the three semiconductor laser elements are disposed so that their emission end faces lie in a common plane. 
     Furthermore, the light reflecting members respectively corresponding to the three semiconductor laser elements are disposed so that the distances from the emission end faces of the corresponding semiconductor laser elements are equal. In the example shown in  FIG.  6   , the emission end faces of the three semiconductor laser elements are aligned, and the light reflecting faces of the three light reflecting members are also aligned. Moreover, the emission end faces are in parallel to the sides of the light reflecting faces on the semiconductor laser element side. 
     Furthermore, the light reflecting face each light reflecting members defines the same angle with the upper face of the bottom part of the base  210 . In the example shown in  FIG.  6   , each light reflecting member is designed to define a 45 degree angle between the bottom face and the light reflecting face, and thus the angle defined with the upper face of the bottom part of the base  210  is also substantially 45 degrees. The light travelling in the direction perpendicular to the emission end faces will be reflected by the light reflecting faces of the light reflecting members, and travel upwards in the direction perpendicular to the upper face of the bottom part of the base  210 . 
     The three semiconductor laser elements emit ellipse-shaped lights, and the emitted light travelling perpendicular to the emission end faces travels parallel to the planar face of the base  210  on which the light reflecting members are disposed. In addition, the emission positions are aligned to be at the same height from the surface of the base  210 , thus the positions where the lights travelling perpendicular to the emission end faces irradiates the light reflecting faces are aligned. 
     If the elliptical shapes of the emitted lights match, the lights emitted from three semiconductor laser elements would irradiate the corresponding light reflecting members in the same or a similar manner, and would pass through the lens parts and be output in the same or a similar manner. In contrast, in the semiconductor light emitting device  2  according to the second embodiment, the emitted lights respectively emitted from the three semiconductor laser elements have different elliptical shapes. For example, the semiconductor laser element  230  has a larger elliptical irradiation region than those of the semiconductor laser elements  231  and  232 . In  FIG.  6   , similar to  FIG.  3   , the irradiation regions of the emitted lights from the semiconductor laser elements are indicated as L 1 , L 2 , and L 3 . In the second embodiment, only the light emitted from the semiconductor laser element  230  has the irradiation region beyond the light reflecting face of the corresponding light reflecting member. 
     The light emitting device  2  according to the second embodiment is designed to have substantially the same emission end faces of the semiconductor laser elements, shapes, sizes or angles of the light reflecting faces of the light reflecting members, and the like among the three semiconductor laser elements or three light reflecting members, but the present disclosure is applicable to other designs. For example, a certain semiconductor laser element may be positioned farther from the light reflecting member, a certain light reflecting member may have a larger light reflecting face, and the angle of the light reflecting face may be adjusted for each semiconductor laser element. However, for example, positioning a certain semiconductor laser element farther from the light reflecting member possibly affects the size of the framed space to be secured, which might affect the size of the lateral parts of the base  210 . Increasing the size of a light reflecting face possibly increase the height of the light reflecting member, which might affect the height of the lateral faces of the base  210 . In other words, depending on how the semiconductor laser elements, the submounts, and the light reflecting members are arranged, the size of the light emitting device might become larger than that of the light emitting device  2 . Moreover, if a certain semiconductor laser element is positioned farther from the light reflecting member, the light travelling towards the component-disposing face might not irradiate the light reflecting face. This is because the light travelling towards the component-disposing face advances downwards as the distance to the light reflecting face increases. All three semiconductor laser elements may be disposed on a single submount. Also, a single light reflecting member with one or more light reflecting faces may be provided which reflects light emitted from three semiconductor laser elements. 
     In  FIG.  7   , the broken lines L 1 , L 2 , and L 3  show the passing regions where the main portions of the emitted light from the first semiconductor laser element  230 , the second semiconductor laser element  231 , and the third semiconductor laser element  232  pass through the lens member  250  before being output. 
     As shown by the broken lines L 1  to L 3 , the passing region of the main portion of the light emitted from one semiconductor laser element is contained in one lens part. Moreover, as shown by the broken line L 1 , the main portion of the light emitted from the first semiconductor laser element  230  has the light passing through the first lens shape  251  and the light passing through the second lens shape  252 . 
     The lens shape of each lens part is designed in accordance with the characteristics of the light emitted from the corresponding semiconductor laser element, such as the wavelength and focal point. As shown in  FIG.  6   , in the light emitting device  2  according to the second embodiment, a portion of the main portion of the light emitted from the first semiconductor laser element  230  has non-reflected light not irradiating the light reflecting face of the first light reflecting member  240 . On the other hand, the main portion of the emitted light from the second semiconductor laser element  231  is entirely reflected by the light reflecting face of the second light reflecting member  241 , and the main portion of the emitted light from the third semiconductor laser element  232  is entirely reflected by the light reflecting face of the third light reflecting member  242 . 
     Accordingly, the first to third lens parts each have a first lens shape (the reflected light passing region) to control the reflected light, in other words, the light emitted from the corresponding semiconductor laser elements that is reflected by the light reflecting faces of the corresponding light reflecting members. The first lens part  253  also has a second lens shape (the non-reflected light passing region) to control non-reflected light, in other words, the light emitted from the corresponding semiconductor laser element that does not irradiate the light reflecting face and travel outside the light reflecting face. The second lens part  254  and the third lens part  255  each has no second lens shape (the non-reflected light passing region) because the entire main portions of the light emitted from the corresponding semiconductor laser elements are reflected by the corresponding light reflecting faces. The second lens part  254  and/or the third lens part  255  may each have a second lens shape. Accordingly, the lens member  250  can apply the intended controls to at least the main portions of the light emitted from the first to the third semiconductor laser elements. 
     In the light emitting device  2  according to the second embodiment, the lens member  250  has a lens shape where multiple lens parts are linked, but the size of each lens part is preferably large enough to cover the region through which the light from the corresponding semiconductor laser element passes at the very least. In addition, semiconductor laser elements need to be arranged close together in order to reduce the size of the light emitting device  2 , thus the lens member  250  is formed to a size in accordance with that. In the case where the lengths of the lens parts corresponding to the major diameters of the elliptical beams are larger than the distance between two adjacent semiconductor laser elements, the widths of the lens parts corresponding to the minor diameters of the elliptical beams need to be designed smaller than the lengths corresponding to the major diameters. 
     In the light emitting device  2  according to the second embodiment, the sum of the half value of the lens length of the first lens part  253  corresponding to the major diameter of the beam and the half value of the lens length of the second lens part  254  corresponding to the major diameter of the beam is larger than the distance between the first semiconductor laser element  230  and the second semiconductor laser element  231 . Accordingly, each lens part is not semispherical, but has the linked structure shown in  FIG.  7   , and the widths of the lens parts corresponding to the minor diameters of the elliptical beams are smaller than the lengths of the lens parts corresponding to the major diameters of the beams. 
       FIG.  8    is a cross-sectional view of the light emitting device  2  taken along straight line VIII-VIII in  FIG.  6   . As shown in  FIG.  8   , the portion of the emitted light from the first semiconductor laser element  230  that is reflected by the light reflecting face of the first light reflecting member  240  passes through the cover  260  and the space between the lens member  250  and the cover  260  created by the bonding part  270  before entering the lens member  250 . Then the light entering the lens member  250  passes through the first lens shape  251  of the first lens part  253  before exiting from the light emitting device  2 . In the example shown in  FIG.  8   , the output light travels in the direction perpendicular to the substrate  200 . 
     The portion of the emitted light from the first semiconductor laser element  230  that travels upwards of the light reflecting face of the first light reflecting member  240  without being reflected by the light reflecting face passes through the cover  260  and the space between the lens member  250  and the cover  260  created by the bonding member  270  before entering the lens member  250 . Then the light entering the lens member  250  passes through the second lens shape  252  of the first lens part  253  before exiting from the light emitting device  2 . As shown in  FIG.  8   , the output light also travels in the direction perpendicular to the substrate  200 . 
     Accordingly, both reflected light and non-reflected light of the emitted light from the first semiconductor laser element  230  can be collimated in the same direction when externally output. Moreover, the lights emitted from the second semiconductor laser element  231  and the third semiconductor laser element  232  can also be collimated when exiting from the light emitting device  2  in the same direction as that of the light output from the first semiconductor laser element  230 . A light emitting device can thus be provided where the red, green, and blue light output directions are controlled. 
     Even though the emitted light from the first semiconductor laser element  230  passes through another member such as the cover  260  before entering the lens member  250  by way of or not by way of the light reflecting face of the first light reflecting member  240 , the light emitting device  2  is the same as the light emitting device  1  according to the first embodiment at the point that the first lens part  253  has the first lens shape designed to control reflected light and a second lens shape designed to control non-reflected light. 
     In the light emitting device  2  according to the second embodiment, the vertical beam divergence of at least one of the semiconductor laser elements is larger than the vertical beam divergence of the other semiconductor laser elements. If the light reflecting face of the light reflecting member is enlarged so that the entire emitted light from the semiconductor laser element having a large vertical beam divergence irradiates the light reflecting face, the height of the light reflecting member would increase, to thereby increase the size of the light emitting device  2 . 
     In the light emitting device  2  according to the second embodiment, a light reflecting face large enough to reflect the entire emitted light from the semiconductor laser element having the smallest vertical beam divergence is secured, while allowing a portion of the emitted light from the semiconductor laser element having a larger vertical beam divergence does not irradiate the light reflecting face. Thus, a smaller light emitting device  2  can be achieved as compared to matching the size of the light reflecting face with the light having a large vertical beam divergence. 
     The light emitting device  2  according to the second embodiment has a lens part having a first lens shape and a second lens shape, and lens parts each having a first lens shape, but not a second lens shape. Moreover, the length of the major diameter of the lens part corresponding to the vertical beam spread is smaller in the case of the lens part having a second lens shape than in the case of the lens parts having no second lens shape. Thus, providing a second lens shape does not increase the size of the lens part. 
     Example 1 
     An example of the second light emitting device  2  described with reference to the second embodiment will be explained next. The light emitting device  2  of Example 1 has a substrate  200  that is about 10 mm per side where the S1 side is about a few mm larger than the S2 side. The length of the outer lateral faces of the base  210  is about 7.0 mm on the S1 side, and about 6.0 mm on the S2 side. The height from the lower face of the bottom part of the base  210  to the apex of the lens part of the lens member  250  is about 5.1 mm, and if the thickness of the substrate  200  is included, the height of the light emitting device  2  is about 6.0 mm. 
     The height of the base  210  from the lower face of its bottom part to the upper faces  211  of its lateral parts is about 2.0 mm, the height of the lens member  250  from its lower face to its apex is about 2.5 mm, and the height of a lens part from the bottom face to the apex is about 1.90 mm. The bottom face of the lens part refers to a planar face on which the lens part is placed, assuming the lens portion is configured with the lens shape and the planar face placed thereon. The height from the lower face of the lens member  250  to the bottom faces of the lens parts is about 0.6 mm. 
     The length of the side of the lens member  250  is about 6.0 mm on the S1 side and about 5.5 mm on the S2 side, the length of a lens part is about 5.0 mm in the S1 direction. The spacing between adjacent semiconductor laser elements is about 1.25 mm, the lengths of the first lens part  253 , the second lens part  254 , and the third lens part  255  corresponding to the vertical beam spread is respectively about 4.32 mm, about 4.48 mm, and about 4.46 mm. The length of the first lens shape assuming that there is no second lens shape is about 4.43 mm. The length of each lens part in the S1 direction is 1.87 mm for the first lens part  253 , 1.25 mm for the second lens part  254 , and 1.88 mm for the third lens part  255 . 
     The length of the irradiation region corresponding to the major diameter of the elliptical beam which is the passing region in the first lens part  253  corresponding to the main portion of the emitted light from the red light emitting first semiconductor laser element  230  is about 4.0 mm. The length of the irradiation region corresponding to the major diameter of the elliptical beam which is the passing region in the second lens part  254  corresponding to the main portion of the emitted light from the green light emitting second semiconductor laser element  231  is 3.3 mm. The length of the irradiation region corresponding to the major diameter of the elliptical beam which is the passing region in the third lens part  255  corresponding to the main portion of the emitted light from the blue light emitting third semiconductor laser element  232  is about 3.3 mm. Similarly, the lengths of the irradiation regions corresponding to the minor diameters of the elliptical beams are respectively about 0.80 mm, about 0.65 mm, and about 0.80 mm. 
     As described above, in the light emitting device  2  of Example 1, the length of the irradiation region corresponding to the major diameter of the elliptical beam of each laser is larger than the distance between adjacent semiconductor laser elements. The lengths of the lens parts covering the irradiation regions are larger than the length of the irradiation regions, but if the lengths of the lens parts corresponding to the minor diameters of the beams are the same, the distances between the semiconductor laser elements must be increased accordingly. This will increase the sizes of the lateral parts of the base  210  which consequently increases the package size. In order to reduce the package size, it would be better to adjust the shapes of the lens parts in accordance with the spaces between the semiconductor laser elements and form the lens parts, rather than adjusting the spaces between the semiconductor laser elements in accordance with the lens diameters of the lens parts. 
     In the light emitting device  2  of Example 1, moreover, three semiconductor laser elements are disposed in the frame of the base  210  having the outer lateral faces which is about 7.0 mm in length on the S1 side and about 6.0 mm in length on the S2 side, and red, green, and blue beams are individually collimated before being externally output from the light emitting device. In measuring the optical characteristics of the beams in the three colors, such as the luminous intensity and peak wavelength, the main portions of the beams can separately be dispersed by using multiple dichroic mirrors. For example, the red collimated light emitted from the first lens part  253  is allowed to travel towards one dichroic mirror, and the green collimated light emitted from the second lens part  254  is allowed to travel towards another dichroic mirror. The beams in the three colors travel in different directions, thus the optical characteristics of the beams in three color lights emitted from the light emitting device  2  of Example 1 can be measured by providing a measuring device at each destination while allowing the device to simultaneously output beams in three colors. In this manner, the measurement can be efficiently performed more than a case where measuring while allowing it to emit one beam of a color at a time. 
     Light emitting devices according to the present disclosure have been described above based on embodiments and examples, but the light emitting devices embodying the technical ideas of the present disclosure are not required to these. For example, semiconductor laser elements are employed as light emitting elements, but other light emitting elements may be used instead. The first to third semiconductor laser elements described are examples of the first to third light emitting elements. 
     In a light emitting device according to the present disclosure, when the emitted light from a light emitting element travels towards a light reflecting member, the light irradiates the light reflecting face of a light reflecting member while having a shape with some extent of a width but not like a dot shape. In addition, a portion of the light passes without irradiating the light reflecting member. In such a situation, a light emitting device having the lens member according to the present disclosure can control both reflected light and non-reflected light. 
     Moreover, light emitting devices having the technical characteristics disclosed herein are not required to those having the structures of the light emitting device  1  or the light emitting device  2 . For example, the present disclosure is applicable to a light emitting device having a constituent element not disclosed in the first or the second embodiment, and the fact that there is a difference from the disclosed light emitting devices would not form the grounds for negating the applicability of the present disclosure. Furthermore, a constituent element which is disclosed in the second embodiment, but not disclosed in the first embodiment, can be incorporated into a light emitting device according to the first embodiment. 
     This, in other words, indicates that the present disclosure is applicable to even a light emitting device which does not make it essential to necessarily and fully include all of the constituent elements of the light emitting device disclosed by the first embodiment or the second embodiment. For example, in the case where the claim scope does not disclose a certain element of the light emitting device described by the first embodiment or the second embodiment, such an element is not limited to that disclosed by the embodiment, and the present disclosure disclosed in the claim scope is still applicable when recognizing design flexibility for a person having ordinary skills in the art, such as employing an alternative, making an omission or a change in the shape or the materials for the constituent element. 
     The light emitting device disclosed in the embodiments can be used in projectors, automotive headlights, lighting fixtures, display backlights, and the like.