Patent Description:
The use of a lens in collecting, dispersing, or collimating the emitted light from a light emitting element has been known. For example, <CIT> 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. <CIT> discloses a light emitting device according to the preamble of claim <NUM>.

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.

The present invention is defined in independent claim <NUM>. The dependent claims define embodiments of the invention. A light emitting device according to the present disclosure includes a first light emitting element, a first light reflecting member and a lens member. The first light emitting element is configured to emit light. The first light reflecting member has 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 is 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 having 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, and a non-reflected light passing region having 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.

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.

<FIG> is a schematic diagram of the light emitting device <NUM> according to a first embodiment. The light emitting device <NUM> includes a base <NUM>, at least one submount <NUM>, at least one semiconductor laser element <NUM>, at least one light reflecting member <NUM>, and at least one lens member <NUM>. In the light emitting device <NUM>, the submount <NUM>, the semiconductor laser element <NUM>, the light reflecting member <NUM>, and the lens member <NUM> are arranged on the planar face of the base <NUM>. Moreover, the component-disposing surface (the planar face in this example) of the base <NUM> on which the light reflecting member <NUM> is disposed is used as a reference surface. The lens member <NUM> is disposed further upwards of the semiconductor laser element <NUM> and the light reflecting member <NUM> disposed on the component-disposing surface serving as the reference surface. The constituent elements of the light emitting device <NUM> will be explained below. The term, "upwards," in the description herein refers to the direction in which the semiconductor laser element <NUM> is disposed using the component-disposing surface of the base <NUM> as a reference.

The base <NUM> has a planar face on which the submount <NUM> and the light reflecting member <NUM> directly disposed. The semiconductor laser element <NUM> is disposed on the planar face of the base member <NUM> via the submount <NUM>. 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 <NUM> has electrodes for electrically connecting the semiconductor laser element <NUM> to an external power source, and the semiconductor laser element <NUM> will be electrically connected to the electrodes. The base <NUM> thus has a function of electrically connecting the semiconductor laser element <NUM> to an external power source. For the base <NUM>, a ceramic, metal, composite of these, or the like can be used.

The submount <NUM> has a bottom face to which the base <NUM> is bonded, and has an upper face on which the semiconductor laser element <NUM> is disposed. The submount <NUM> has a function of securing an adequate height from the upper face of the base <NUM> to the light emission point at which the semiconductor laser element <NUM> emits light. Accordingly, the submount <NUM> can be omitted if the semiconductor laser element <NUM> can secure an adequate height on its own. By using a submount <NUM> formed of a material having higher thermal conductivity than that of the base <NUM>, the submount <NUM> has a function of improving heat dissipation in addition to securing the height. In the light emitting device <NUM>, the semiconductor laser element <NUM> has the light emission point on the lateral face that is closer to the light reflecting member <NUM>, and light is emitted from the light emission point towards the light reflecting member <NUM>.

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 <NUM> to directly irradiate the base <NUM>. Using the component-disposing face of the base <NUM> as a reference, the emitted light from the semiconductor laser element <NUM> 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 <NUM>. 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 <NUM>, the distance between the semiconductor laser element <NUM> and the light reflecting member <NUM> 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's peak intensity value to a given intensity, such as <NUM>/e<NUM>.

For the submount <NUM>, one that suitably adheres the base <NUM> to the semiconductor laser element <NUM> is preferable. In the case of using a material containing nitride semiconductors for the semiconductor laser element <NUM> and an aluminum nitride as a base material for the base <NUM>, for example, an aluminum nitride or silicon carbide can be used for the submount <NUM>. A metal film is disposed on the submount <NUM>, and the semiconductor laser element <NUM> is secured to the submount <NUM> using a conductive layer such as Au-Sn.

The bottom face of the semiconductor laser element <NUM> is bonded to the submount <NUM>, and the semiconductor laser element emits light from the lateral face that is closer to the light reflecting member <NUM>. The emitted light from the semiconductor laser element <NUM> 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 <NUM> is bonded to the base <NUM>, and the light reflecting member <NUM> reflects the emitted light from the semiconductor laser element <NUM>. The light reflected by the light reflecting member <NUM> travels towards the lens member <NUM> located upwards thereof. The optical path length of the emitted light from the semiconductor laser element <NUM> to the lens member <NUM> tends to be larger when the light travels by way of the light reflecting member <NUM> than in the case of not by way of the light reflecting member <NUM>. A longer optical path length can reduce the impact of a misalignment between the light reflecting member <NUM> and the semiconductor laser element <NUM>.

The light reflecting member <NUM> has a light reflecting face on at least one face. The light reflecting member <NUM> receives the light from the semiconductor laser element <NUM> 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 <NUM> 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 <NUM> may be formed of a metal or dielectric multilayer. The light emitting device <NUM> may include a light reflecting member <NUM> having multiple light reflecting faces or another light reflecting member in addition to the light reflecting member <NUM>, as needed.

The lens member <NUM> is disposed in the position where the emitted light from the semiconductor laser element <NUM> enters. The light entering the lens member <NUM> includes the light entering after being reflected by the light reflecting member <NUM>, and the light entering after travelling upwards of the light reflecting member <NUM> without being reflected by the light reflecting member <NUM>. To simplify the description, the light entering after being reflected by the light reflecting member <NUM> will be hereinafter referred to as "reflected light", and the light entering after travelling above the light reflecting member <NUM> without being reflected by the light reflecting member <NUM> will be referred to as "non-reflected light". For the lens member <NUM>, for example, a glass material such as BK7 and B270 can be used.

<FIG> is a schematic diagram explaining the structure of the lens member in the light emitting device <NUM> according to the first embodiment of the present disclosure. <FIG> is a perspective view of the light emitting device <NUM> to illustrate the emitted light from the semiconductor laser element <NUM> according to the first embodiment. The lens member <NUM> is not shown in <FIG> for clarity of explanation.

As shown in <FIG>, the lens member <NUM> of the light emitting device <NUM> includes a reflected light passing region having a first lens shape <NUM> and a non-reflected light passing region having a second lens shape <NUM>. The first lens shape <NUM> has a lens shape designed to control the portion of the emitted light from the semiconductor laser element <NUM> that is reflected light. On the other hand, the second lens shape <NUM> has a lens shape designed to control the non-reflected light. Specifically, in the light emitting device <NUM> according to the first embodiment, the lens shape of the first lens shape <NUM> is designed based on the focal point FR of the reflected light and the lens shape of the second lens shape <NUM> is designed based on the focal point FD of the non-reflected light. The optical controls using the lens member <NUM> include, for example, collecting, dispersing, and collimating light.

The solid arrowed lines in <FIG> and <FIG> indicate the travelling directions of the light L emitted from the semiconductor laser element <NUM>. The broken line in <FIG> indicates the irradiation region where the main portion of the emitted light from the semiconductor laser element <NUM> irradiates the plane where the light reflecting face <NUM> of the light reflecting member <NUM> is present.

The semiconductor laser element <NUM> 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>, in the light emitting device <NUM>, a portion of the irradiation region is not contained in the light reflecting face <NUM> of the light reflecting member <NUM>. This portion of light does not irradiate the light reflecting face <NUM>, but passes upwards of that. The portion of the emitted light from the semiconductor laser element <NUM> that irradiates and is reflected by the light reflecting face <NUM> constitutes reflected light, and the light that does not irradiate the light reflecting face <NUM> and travels upwards of the light reflecting face <NUM> 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 <NUM>. Specifically, a lower end of a vertical divergence of the main portion of the emitted light from the semiconductor laser element <NUM> is present in the light reflecting face <NUM> of the light reflecting member <NUM>. 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 <NUM> is non-reflected light passing outside the light reflecting member <NUM>, and that travelling towards the component-disposing face of the base <NUM> is reflected light which irradiates and is reflected by the light reflecting face <NUM>. The upper edge of the light reflecting face <NUM> can be understood as the boundary between reflected light and non-reflected light. In other word, the light reflecting member <NUM> is positioned with respect to the semiconductor laser element <NUM> so that emitted light from the semiconductor laser element <NUM> is divided into a portion of the emitted light from the semiconductor laser element <NUM> irradiating onto the light reflecting face <NUM> and a portion of the emitted light from the semiconductor laser element <NUM> traveling outside of the light reflecting face <NUM> by having the edge of the light reflecting face <NUM> serve as the boundary.

As shown in <FIG>, the first lens shape <NUM> is for controlling the output direction of the reflected light travelling upwards by way of the light reflecting member <NUM>, thus it is designed so that the light reflected at the boundary passes through the first lens shape <NUM> before externally output from the lens member <NUM>. The first lens shape <NUM> 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 <NUM> also passes through the first lens shape <NUM> before externally output from the lens member <NUM>.

In the case where the light irradiating the point LD (in <FIG>) and reflected irradiates the semiconductor laser element <NUM> or the submount <NUM> and not entering the lens member <NUM>, the light reflected at a position near the lower edge of the light reflecting face <NUM> includes light that does not enter the lens member <NUM>. The materials composing and the size of the semiconductor laser element <NUM>, the laser beam divergence angle, the angle of the light reflecting face <NUM> of the light reflecting member <NUM>, 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 <NUM> 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 <NUM> 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 <NUM> that travels towards the upper edge UE of the semiconductor laser element <NUM> as shown in <FIG>. The upper edge UE is a boundary between the reflected light directly travelling toward the incident face of the lens member <NUM> 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 <NUM> and the incident face of the lens member <NUM>.

The second lens shape <NUM> can conceivably be designed so that the portion of the emitted light from the semiconductor laser element <NUM> that is emitted most upwards passes through the second lens shape <NUM> before being externally output from the lens member <NUM>. The lens member <NUM> may be designed so that the straight line connecting the light emission point FD of the semiconductor laser element <NUM> and the upper edge boundary of the light reflecting face <NUM> passes through the second lens shape <NUM>. Thus, the light travelling outside the light reflecting face <NUM>, in other words, the entire non-reflected light passing upwards of the boundary of the light reflecting face <NUM> can be output from the second lens shape <NUM> in <FIG>.

The boundary between the first lens shape <NUM> and the second lens shape <NUM> 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 <NUM>. This can avoid the situation where the reflected light passes through the second lens shape <NUM> and the non-reflected light passes through the first lens shape <NUM>. Considering the manufacturing tolerance of the light emitting device <NUM>, however, it is desirable to set the boundary DP between the first lens shape <NUM> and the second lens shape <NUM> at a position farther from the intersection point CP as shown in <FIG>. 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 <NUM> and the path of light reflected at the boundary of the light reflecting face <NUM> 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 <NUM>. 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 <NUM> as a whole. Accordingly, in order to reduce the size of the light emitting device <NUM>, 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 <NUM>. In this case, it is preferable to make this region the first lens shape <NUM> 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 <NUM> is preferably designed by taking into consideration the manufacturing tolerance so that the light reflected at the upper edge of the light reflecting face <NUM> passes through the first lens shape <NUM>, and is preferably designed so that the entire reflected light in the main portion of the light passes through the first lens shape <NUM>.

In <FIG>, 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 <NUM> that travels perpendicularly to the emission end face is in parallel to the bonding face between the base <NUM> and the light reflecting member <NUM>, 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.

<FIG> show examples of how the lens member <NUM> controls light. <FIG> 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 <NUM> and the second lens shape <NUM> have the shapes to function as collimating lenses for collimating reflected light and non-reflected light, respectively. The first lens shape <NUM> is designed so as to collimate the light from the focal point FR to a given direction, and the second lens shape <NUM> 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 <NUM>. In this manner, in the case where a portion of the emitted light from the semiconductor laser element <NUM> 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> shows a case where reflected light and non-reflected light are collimated in different directions. Accordingly, the first lens shape <NUM> and the second lens shape <NUM> 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 <NUM> 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> shows an optical control where reflected light and non-reflected light are collected to the same point. In this case, the first lens shape <NUM> and the second lens shape <NUM> 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 <NUM> is non-reflected light, for example, a larger amount of light can be collected than in the case of utilizing only reflected light.

<FIG> shows an optical control that collects reflected light and non-reflected light at different points, and the first lens shape <NUM> and the second lens shape <NUM> 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 <NUM> 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 <NUM> and the second lens shape <NUM> 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 <NUM> according to the first embodiment can achieve light output controls tailored to both portions of the emitted light from the semiconductor laser element <NUM> that are reflected light and non-reflected light.

A light emitting device <NUM> according to a second embodiment externally outputs the emitted light from multiple semiconductor laser elements through the lens member. The light emitting device <NUM> 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> are diagrams illustrating the light emitting device <NUM>. <FIG> is a perspective view of the light emitting device <NUM>. <FIG> is a top view showing the constituent elements arranged in the frame of the base <NUM> of the light emitting device <NUM>. <FIG> is a top view of the light emitting device <NUM>. <FIG> is a cross-sectional view of the light emitting device taken along line VIII-VIII in <FIG>. For clarity of explanation, <FIG> shows the state where the cover <NUM> bonded to the base <NUM> is omitted from the light emitting device <NUM>. In <FIG>, dotted lines S <NUM> and S2 are supplemental lines to indicate how the orientation of the light emitting device <NUM> correspond among the drawings, and are not constituent elements of the light emitting device <NUM>.

As shown in <FIG>, the light emitting device <NUM> has a substrate <NUM> serving as a mounting substrate, a base <NUM> serving as a package, a cover <NUM>, a bonding part <NUM>, and a lens member <NUM>. The base <NUM> has a recessed shape as a whole, and as shown in <FIG>, 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 <NUM>.

Specifically, on the planar face in the frame of the base <NUM>, a first semiconductor laser element <NUM>, a second semiconductor laser element <NUM>, a third semiconductor laser element <NUM>, a first submount <NUM> on which the first semiconductor laser element <NUM> is disposed, a second submount <NUM> on which the second semiconductor laser element <NUM> is disposed, a third submount <NUM> on which the third semiconductor laser element <NUM> is disposed, a first light reflecting member <NUM> corresponding to the first semiconductor laser element <NUM>, a second light reflecting member <NUM> corresponding to the second semiconductor laser element <NUM>, and a third light reflecting member <NUM> corresponding to the third semiconductor laser element <NUM> are disposed. The constituent elements of the light emitting device <NUM> will be explained below.

The substrate <NUM> is bonded to the base <NUM> and has a function of electrically connecting the semiconductor laser elements disposed on the planar face of the base <NUM>. The multiple metal films <NUM> shown in <FIG> are for that purpose. On the upper face of the substrate <NUM>, three pairs of metal film <NUM> are disposed respectively corresponding to the semiconductor laser elements. Each metal film <NUM> has an insulating film-covered region <NUM>, while regions <NUM> and <NUM> of the metal film are not covered. The insulating film <NUM> can reduce the spreading of solder onto the metal film region <NUM> when the base <NUM> is soldered to the substrate <NUM>. The substrate <NUM> can be formed using a combination of an insulating material, such as a ceramic, and a conductive material, such as a metal.

The base <NUM>, as shown in <FIG>, has a bottom part and lateral parts, and the recess is defined by the upper face <NUM> 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 <NUM> of the lateral parts of the base <NUM> are bonded to the cover <NUM>, and the lower face of the bottom part is bonded to the substrate <NUM>. As shown in <FIG>, multiple light reflecting members and the submounts respectively corresponding to the semiconductor laser elements are directly disposed on the upper face <NUM> 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 <NUM>. 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 <NUM>.

As shown in <FIG> and <FIG>, the base <NUM> has one or more stepped portions inside the recess at some of the lateral parts. In the example shown in <FIG>, 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 <NUM> is formed on the planar faces <NUM> formed by the stepped portions, in other words, the planar faces <NUM> formed between the inner lateral faces meeting the upper face <NUM> of the bottom part of the base <NUM> and the inner lateral faces of the lateral parts meeting the upper faces <NUM> of the lateral parts of the base <NUM>. Each semiconductor laser element can receive the supply of power from the outside of the light emitting device <NUM> by electrically connecting the metal film using wires.

The cover <NUM> is bonded to the base <NUM> to thereby cover the framed area surrounded by the lateral parts of the base <NUM>. A metal film is disposed in the area of the lower face of the cover <NUM> to be bonded to the base <NUM>, and the base <NUM> and the cover <NUM> are bonded and fixed via AuSn or the like. The closed space formed by bonding the base <NUM> and the cover <NUM> 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 <NUM>, 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 <NUM> 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 <NUM> is formed by the adhesive that bonds the cover <NUM> and the lens member <NUM>. The bonding part <NUM> adheres to the upper face of the cover <NUM> and the lower face of the lens member <NUM> thereby fixing the cover <NUM> and the lens member <NUM>. The bonding part <NUM> is not formed across the entire upper face of the cover <NUM> or the entire lower face of the lens member <NUM>, 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 <NUM> is preferably formed by not forming it in the areas of the lower face of the lens member <NUM> that correspond to the regions where the first lens part <NUM>, the second lens part <NUM>, and the third lens part <NUM> are formed, but instead by forming it in the outer peripheral region of the lens member <NUM>. For the adhesive that forms the bonding part <NUM>, 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 <NUM> at a desired position.

The lens member <NUM> has a lens shape where multiple lens parts are linked. Specifically, a first lens part <NUM>, a second lens part <NUM>, and a third lens part <NUM> are linked, lens parts allowing light from semiconductor laser elements to respectively pass through. The first lens part <NUM> has a first lens shape <NUM> and a second lens shape <NUM>. The first lens shape <NUM> (the reflected light passing region) and the second lens shape <NUM> (the non-reflected light passing region) of the first lens part <NUM> are linked to the first lens shape <NUM> (the reflected light passing region) of the second lens part <NUM>. The first lens shape <NUM> and the second lens shape <NUM> are the same as or similar to the first lens shape <NUM> and the second lens shape <NUM> explained with reference to the first embodiment.

The light emitting device <NUM> according to the second embodiment includes three semiconductor laser elements where red light L1 emitted by the first semiconductor laser element <NUM> passes through the first lens part <NUM>, blue light L2 emitted by the second semiconductor laser element <NUM> passes through the second lens part <NUM>, and green light L3 emitted by the third semiconductor laser element <NUM> passes through the third lens part <NUM>. The first lens shape <NUM> of the first lens part <NUM> is designed to collimate reflected red light, and the second lens shape <NUM> of the first lens part <NUM> is designed to collimate non-reflected red light. The second lens part <NUM> is designed to have a lens shape to collimate reflected blue light, and the third lens part <NUM> 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 <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>. 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 <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>. 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 <NUM> to <NUM>, more preferably in the range of from <NUM> to <NUM>. 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 <NUM> 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 <NUM> among the three semiconductor laser elements is positioned in the middle of the light emitting device <NUM> because the semiconductor laser element <NUM> 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 <NUM> corresponding to the first semiconductor laser element <NUM>, a second light reflecting member <NUM> corresponding to the second semiconductor laser element <NUM>, and a third light reflecting member <NUM> corresponding to the third semiconductor laser element <NUM> are disposed on the planar face of the base <NUM>.

In the frame of the base <NUM>, the first semiconductor laser element <NUM>, the second semiconductor laser element <NUM>, and the third semiconductor laser element <NUM> 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>, 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 <NUM>. In the example shown in <FIG>, each light reflecting member is designed to define a <NUM> 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 <NUM> is also substantially <NUM> 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 <NUM>.

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 <NUM> 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 <NUM>, 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 <NUM> 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 <NUM> has a larger elliptical irradiation region than those of the semiconductor laser elements <NUM> and <NUM>. In <FIG>, similar to <FIG>, the irradiation regions of the emitted lights from the semiconductor laser elements are indicated as L1, L2, and L3. In the second embodiment, only the light emitted from the semiconductor laser element <NUM> has the irradiation region beyond the light reflecting face of the corresponding light reflecting member.

The light emitting device <NUM> 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 <NUM>. 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 <NUM>. 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 <NUM>. 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>, the broken lines L1, L2, and L3 show the passing regions where the main portions of the emitted light from the first semiconductor laser element <NUM>, the second semiconductor laser element <NUM>, and the third semiconductor laser element <NUM> pass through the lens member <NUM> before being output.

As shown by the broken lines L1 to L3, 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 L1, the main portion of the light emitted from the first semiconductor laser element <NUM> has the light passing through the first lens shape <NUM> and the light passing through the second lens shape <NUM>.

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>, in the light emitting device <NUM> according to the second embodiment, a portion of the main portion of the light emitted from the first semiconductor laser element <NUM> has non-reflected light not irradiating the light reflecting face of the first light reflecting member <NUM>. On the other hand, the main portion of the emitted light from the second semiconductor laser element <NUM> is entirely reflected by the light reflecting face of the second light reflecting member <NUM>, and the main portion of the emitted light from the third semiconductor laser element <NUM> is entirely reflected by the light reflecting face of the third light reflecting member <NUM>.

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 <NUM> 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 <NUM> and the third lens part <NUM> 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 <NUM> and/or the third lens part <NUM> may each have a second lens shape. Accordingly, the lens member <NUM> 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 <NUM> according to the second embodiment, the lens member <NUM> 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 <NUM>, thus the lens member <NUM> 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 <NUM> according to the second embodiment, the sum of the half value of the lens length of the first lens part <NUM> corresponding to the major diameter of the beam and the half value of the lens length of the second lens part <NUM> corresponding to the major diameter of the beam is larger than the distance between the first semiconductor laser element <NUM> and the second semiconductor laser element <NUM>. Accordingly, each lens part is not semispherical, but has the linked structure shown in <FIG>, 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> is a cross-sectional view of the light emitting device <NUM> taken along straight line VIII-VIII in <FIG>. As shown in <FIG>, the portion of the emitted light from the first semiconductor laser element <NUM> that is reflected by the light reflecting face of the first light reflecting member <NUM> passes through the cover <NUM> and the space between the lens member <NUM> and the cover <NUM> created by the bonding part <NUM> before entering the lens member <NUM>. Then the light entering the lens member <NUM> passes through the first lens shape <NUM> of the first lens part <NUM> before exiting from the light emitting device <NUM>. In the example shown in <FIG>, the output light travels in the direction perpendicular to the substrate <NUM>.

The portion of the emitted light from the first semiconductor laser element <NUM> that travels upwards of the light reflecting face of the first light reflecting member <NUM> without being reflected by the light reflecting face passes through the cover <NUM> and the space between the lens member <NUM> and the cover <NUM> created by the bonding member <NUM> before entering the lens member <NUM>. Then the light entering the lens member <NUM> passes through the second lens shape <NUM> of the first lens part <NUM> before exiting from the light emitting device <NUM>. As shown in <FIG>, the output light also travels in the direction perpendicular to the substrate <NUM>.

Accordingly, both reflected light and non-reflected light of the emitted light from the first semiconductor laser element <NUM> can be collimated in the same direction when externally output. Moreover, the lights emitted from the second semiconductor laser element <NUM> and the third semiconductor laser element <NUM> can also be collimated when exiting from the light emitting device <NUM> in the same direction as that of the light output from the first semiconductor laser element <NUM>. 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 <NUM> passes through another member such as the cover <NUM> before entering the lens member <NUM> by way of or not by way of the light reflecting face of the first light reflecting member <NUM>, the light emitting device <NUM> is the same as the light emitting device <NUM> according to the first embodiment at the point that the first lens part <NUM> 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 <NUM> 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 <NUM>.

In the light emitting device <NUM> 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 <NUM> 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 <NUM> 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.

An example of the second light emitting device <NUM> described with reference to the second embodiment will be explained next. The light emitting device <NUM> of Example <NUM> has a substrate <NUM> that is about <NUM> 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 <NUM> is about <NUM> on the S1 side, and about <NUM> on the S2 side. The height from the lower face of the bottom part of the base <NUM> to the apex of the lens part of the lens member <NUM> is about <NUM>, and if the thickness of the substrate <NUM> is included, the height of the light emitting device <NUM> is about <NUM>.

The height of the base <NUM> from the lower face of its bottom part to the upper faces <NUM> of its lateral parts is about <NUM>, the height of the lens member <NUM> from its lower face to its apex is about <NUM>, and the height of a lens part from the bottom face to the apex is about <NUM>. 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 <NUM> to the bottom faces of the lens parts is about <NUM>.

The length of the side of the lens member <NUM> is about <NUM> on the S1 side and about <NUM> on the S2 side, the length of a lens part is about <NUM> in the S1 direction. The spacing between adjacent semiconductor laser elements is about <NUM>, the lengths of the first lens part <NUM>, the second lens part <NUM>, and the third lens part <NUM> corresponding to the vertical beam spread is respectively about <NUM>, about <NUM>, and about <NUM>. The length of the first lens shape assuming that there is no second lens shape is about <NUM>. The length of each lens part in the S1 direction is <NUM> for the first lens part <NUM>, <NUM> for the second lens part <NUM>, and <NUM> for the third lens part <NUM>.

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 <NUM> corresponding to the main portion of the emitted light from the red light emitting first semiconductor laser element <NUM> is about <NUM>. 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 <NUM> corresponding to the main portion of the emitted light from the green light emitting second semiconductor laser element <NUM> is <NUM>. 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 <NUM> corresponding to the main portion of the emitted light from the blue light emitting third semiconductor laser element <NUM> is about <NUM>. Similarly, the lengths of the irradiation regions corresponding to the minor diameters of the elliptical beams are respectively about <NUM>, about <NUM>, and about <NUM>.

As described above, in the light emitting device <NUM> of Example <NUM>, 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 <NUM> 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 <NUM> of Example <NUM>, moreover, three semiconductor laser elements are disposed in the frame of the base <NUM> having the outer lateral faces which is about <NUM> in length on the S1 side and about <NUM> 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 <NUM> is allowed to travel towards one dichroic mirror, and the green collimated light emitted from the second lens part <NUM> 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 <NUM> of Example <NUM> 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 <NUM> or the light emitting device <NUM>. 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.

Claim 1:
A light emitting device comprising:
a base (<NUM>);
a first light emitting element (<NUM>) configured to emit light and disposed on the base (<NUM>);
a first light reflecting member (<NUM>) disposed on the base (<NUM>) and having a light reflecting face (<NUM>) configured to reflect light, the first light reflecting member (<NUM>) being positioned with respect to the first light emitting element (<NUM>) so that emitted light from the first light emitting element (<NUM>) is divided into a portion of the emitted light from the first light emitting element (<NUM>) irradiating onto the light reflecting face (<NUM>) and a portion of the emitted light from the first light emitting element (<NUM>) traveling outside of the light reflecting face (<NUM>) by having an edge of the light reflecting face (<NUM>) serve as a boundary; and
a lens member (<NUM>) located upward to the first light emitting element (<NUM>) and the first light reflecting member (<NUM>) and configured to control a travelling direction of the emitted light from the first light emitting element (<NUM>), the lens member (<NUM>) including
a reflected light passing region having a first lens shape (<NUM>) configured to control the travelling direction of reflected light, which is the portion of the emitted light reflected by the light reflecting face (<NUM>), and
a non-reflected light passing region having a second lens shape (<NUM>) configured to control a travelling direction of non-reflected light, which is the portion of the emitted light travelling outside the light reflecting face (<NUM>),
wherein the base (<NUM>) has a planar face on which the first light emitting element (<NUM>) is disposed,
the light travelling in the direction perpendicular to an emission end face is reflected by the light reflecting face (<NUM>) of the first light reflecting member (<NUM>), and travels upwards in the direction perpendicular to an upper face of the planar face of the base (<NUM>),
characterized in that the light emitting device further comprises:
a cover (<NUM>), wherein
the base (<NUM>) has a bottom part on which the first light emitting element (<NUM>) and the first light reflecting member (<NUM>) are disposed and lateral parts surrounding the first light emitting element (<NUM>) and the first light reflecting member (<NUM>),
the cover (<NUM>) is bonded to an upper face of the lateral parts of the base (<NUM>) and forms a closed space, and
the lens member (<NUM>) is fixed to the cover (<NUM>).