JP2009088353A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of outputting a polarization of a high polarization ratio. <P>SOLUTION: The light emitting device comprises a light emitting element 10 for emitting a first polarization L1 and a second polarization L2 each from a first end face 10a and a second end face 10b, and a package 1 having a packaging surface 1c for packaging the light emitting element 10 and a second inner wall surface 1b for reflecting the second polarization L2 toward a first inner wall surface 1a facing parallel to the first end face 10a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light emitting device that emits polarized light.

Conventionally, a light emitting element made of a group III nitride semiconductor has been used for a light emitting diode (LED). Examples of group III nitride semiconductors include aluminum nitride (AlN), gallium nitride (GaN), and indium nitride (InN). A typical group III nitride semiconductor is represented by Al _x In _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). GaN is a well-known group III nitride semiconductor among hexagonal compound semiconductors containing nitrogen.

A light emitting device using GaN generally has a structure in which an n-type GaN layer, an active layer (light emitting layer), and a p-type GaN layer are stacked on a GaN substrate, and emits light generated in the active layer to the outside. In recent years, use of a light emitting element whose output light is polarized light has been promoted (for example, see Non-Patent Document 1). If a light emitting element that emits polarized light is used as a liquid crystal backlight or projector light source, it is expected that the components of light cut by the polarizer will be reduced and the efficiency of the liquid crystal backlight or projector light source will be improved.
T. Takeuchi, et al., “Japanese Journal of Applied Physics vol.39”, 2000, p. 413-416

  A light-emitting element of a group III nitride semiconductor having a nonpolar or semipolar surface that emits polarized light as a main growth surface is mounted on a package by die bonding, and the mounted light-emitting element is molded with a light-transmitting resin or the like. ing. In this type of light emitting element, not only the polarized light is emitted from the surface facing the irradiated surface, but also the polarized light is emitted from the lateral end face. The polarized light emitted from the lateral end surface orthogonal to the growth main surface is different from the polarization direction of the polarized light emitted from the growth main surface by the emitted lateral end surface, and the polarization direction of the emitted light is not uniform. There was a problem that the polarization ratio as a whole was lowered and the loss due to the polarizer was increased.

  In view of the above problems, an object of the present invention is to provide a light emitting device that emits polarized light having a high polarization ratio.

  According to one aspect of the present invention, a light emitting element that emits the first polarized light and the second polarized light from the first end face and the second end face, respectively, and the first light emitting element mounted on the mounting face and facing the first end face in parallel. The gist of the invention is that the light emitting device includes a package having a second inner wall surface that reflects the second polarized light toward the inner wall surface.

  According to the present invention, it is possible to provide a light emitting device that emits polarized light having a high polarization ratio.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Embodiment)
As shown in FIGS. 1A to 1C, the light emitting device according to the embodiment of the present invention emits the first polarized light L1 and the second polarized light L2 from the first end surface 10a and the second end surface 10b, respectively. 10 and a package 1 having a light emitting element 10 mounted on the mounting surface 1c and having a second inner wall surface 1b that reflects the second polarized light L2 toward the first inner wall surface 1a facing in parallel with the first end surface 10a. Prepare. As shown in FIGS. 1B and 1C, the light emitting element 10 is electrically and mechanically connected to the mounting surface 1c via an adhesive 20 having conductivity. For the adhesive 20, for example, a silver (Ag) paste can be used.

  As shown in FIG. 1A, the package 1 forms a parallelogram having two pairs of opposite sides of the first inner wall surface 1a and the second inner wall surface 1b when viewed from the light extraction direction. . As shown in FIG. 1C, the first inner wall surface 1a has a taper in the vertical direction from the mounting surface 1c.

  As the material of the package 1, ceramics can be used, and the ceramics are manufactured by a firing method. The first inner wall surface 1a and the second inner wall surface 1b of the package 1 are preferably mirror surfaces. Here, the “mirror surface” refers to a surface in which the unevenness of the surface is less than or equal to the wavelength of the light emitted from the light emitting element 10. As an example, the first inner wall surface 1a and the second inner wall surface 1b are mirror surfaces that are mirror-finished so that the unevenness difference is about 100 nm or less. When the first inner wall surface 1a and the second inner wall surface 1b are mirror surfaces, the first polarized light L1 and the second polarized light L2 emitted from the light emitting element 10 are reflected by the first inner wall surface 1a and the second inner wall surface 1b. , Diffuse reflection is reduced, and the polarization characteristics of the first polarization L1 and the second polarization L2 are not disturbed.

  The mirror treatment of the first inner wall surface 1a and the second inner wall surface 1b is performed by forming a metal thin film having a high reflectance such as aluminum (Al) or Ag by electrolytic plating, vapor deposition, sputtering, or the like. The These metal thin films are formed with a film thickness of, for example, several hundred nm to several μm.

  As shown in FIG. 2, the light emitting element 10 includes a substrate 2, a light emitting portion 3 provided on the surface 2 a of the substrate 2, a first electrode portion (anode electrode) 4, a second electrode (cathode electrode) 6, and the like. And a reflective layer 7 provided on the back surface 2 b of the substrate 2. The light emitting portion 3 of the light emitting element 10 includes an active layer 12 made of a group III nitride semiconductor having a nonpolar plane or a semipolar plane as a growth main surface 12a, and a first orthogonal to the growth main surface 12a of the active layer 12. The first polarized light L1 and the second polarized light L2 are generated from the end face 10a and the second end face 10b. The first polarization L1 and the second polarization L2 will be described later.

  The substrate 2 has a hexagonal crystal structure and is made of conductive n-type GaN doped with silicon as an n-type dopant. It is preferable that the board | substrate 2 is the thickness which can be cleaved in a manufacturing process. Specifically, the substrate 2 preferably has a thickness of about 100 μm or less. The surface 2 a of the substrate 2 is a surface for epitaxially growing the light emitting portion 3. The surface 2a of the substrate 2 is an m-plane that is a nonpolar plane.

  Here, a hexagonal crystal structure of a group III nitride semiconductor such as GaN will be described with reference to FIG.

  As shown in FIG. 3A, in a group III nitride semiconductor having a hexagonal crystal structure, four nitrogen atoms are bonded to one group III atom. Four nitrogen atoms are arranged at four vertices of a regular tetrahedron having a group III atom arranged at the center. Of these four nitrogen atoms, one nitrogen atom is arranged in the + c axis direction with respect to the group III atom, and the other three nitrogen atoms are arranged on the −c axis side with respect to the group III atom. Thereby, in the hexagonal group III nitride semiconductor, polarization is formed along the c-axis direction.

  As shown in FIG. 3B, the c-axis is along the direction of the central axis of the hexagonal column, and the plane (the top surface of the hexagonal column) having the c-axis as a normal is the c-plane (0001). When a group III nitride semiconductor crystal is cleaved on two planes parallel to the c plane, the + c plane becomes a crystal plane on which group III atoms are arranged, and the -c plane becomes a crystal plane on which nitrogen is arranged. Therefore, the + c plane and the −c plane are polar planes having different properties.

  A side surface of the hexagonal column is an m-plane (1-100), and a plane passing through a pair of ridge lines that are not adjacent to each other is an a-plane (11-20). Since these are crystal planes adjacent to the c-plane and are orthogonal to the polarization direction, they are nonpolar planes, that is, nonpolar planes. Furthermore, as shown in FIG. 3 (c), the crystal plane that is inclined with respect to the c-plane (not parallel or orthogonal) intersects the polarization direction diagonally, and therefore has a slight polarity. It is a certain plane, that is, a semipolar plane. Specific examples of the semipolar plane include planes such as the (01-11) plane, the (01-13) plane, and the (11-22) plane.

  The light emitting portion 3 is formed by epitaxially growing a group III nitride semiconductor having a hexagonal crystal structure on the surface 2 a of the substrate 2. The light emitting unit 3 includes, in order from the substrate 2 side, a first semiconductor layer (n-type contact layer) 11, an active layer 12, a final barrier layer 13, an electron blocking layer 14, and a second semiconductor layer (p-type contact layer). 15) are stacked. Here, as described above, since the surface 2a of the substrate 2 is composed of m-planes, the surface 3a of the light emitting section 3 and the growth main surface 12a of the active layer 12 stacked on the surface 2a of the substrate 2 are also active. The layer 12 is configured as an m-plane that is a nonpolar plane that emits polarized light.

The first semiconductor layer 11 is made of an n-type GaN layer having a thickness of about 3 μm or more doped with silicon having a concentration of about 1 × 10 ¹⁸ cm ⁻³ as an n-type dopant.

The active layer 12 has a In _Z Ga _1-Z N layer and a thickness of about 9nm thick GaN layer are stacked about 5 cycles alternating quantum well structure having a thickness of about 3nm doped with silicon. The active layer 12 emits blue light (for example, a wavelength of about 430 nm). Here, Z, which is the ratio of In in the In _Z Ga _{1 -Z} N layer, is configured as “0.05 ≦ Z ≦ 0.2”. When green light is emitted, “Z ≧ 0.2” is set.

  The final barrier layer 13 is composed of a GaN layer having a thickness of about 40 nm. The doping may be any of p-type, n-type, and non-doped, but non-doped is preferred.

The electron blocking layer 14 is made of an AlGaN layer having a thickness of about 28 nm doped with magnesium having a concentration of about 3 × 10 ¹⁹ cm ⁻³ as a p-type dopant.

The second semiconductor layer 15 is composed of a p-type GaN layer having a thickness of about 70 nm doped with magnesium having a concentration of about 1 × 10 ²⁰ cm ⁻³ as a p-type dopant. The light extraction surface 3 a of the second semiconductor layer 15 is for extracting light emitted from the active layer 12 from the light emitting unit 3. The surface of the light extraction surface 3a is preferably a mirror surface in order to suppress light scattering and suppress a decrease in the polarization ratio.

  The first electrode portion 4 is made of ZnO that can transmit light. The first electrode unit 4 is ohmically connected to the second semiconductor layer 15 and is arranged on the second semiconductor layer 15 in order to allow a current to flow uniformly in the entire region in the horizontal direction (direction perpendicular to the stacking direction) of the light emitting unit 3. Is formed so as to cover substantially the entire surface. The first electrode portion 4 has a thickness of about 200 nm to about 300 nm that can transmit the light emitted by the active layer 12. The light extraction surface 4a of the first electrode portion 4 is a surface from which light emitted by the active layer 12 is extracted, and the surface unevenness is about 100 nm or less, like the light extraction surface 3a of the second semiconductor layer 15. It is preferable that the mirror surface treatment is performed. For example, if the electron beam evaporation method is used, the mirror surface as described above can be obtained. As described above, the light emitted from the active layer 12 is suppressed by the light extraction surface 3a and the light extraction surface 4a in the mirror surface state, and thus the light is extracted while the polarization ratio is maintained high. A connection portion 5 in which a titanium (Ti) layer and an Au layer are stacked is provided in a partial region on the first electrode portion 4. The connecting portion 5 is used for bonding for connecting to an external substrate or the like.

  As for the 2nd electrode 6, Ti layer and Al layer are laminated | stacked. The second electrode 6 is formed in an ohmic connection with the exposed region of the upper surface of the first semiconductor layer 11.

The reflection layer 7 is for reflecting the light traveling in the direction opposite to the light extraction direction in the light extraction direction, and is formed on the back surface 2b of the substrate 2 which is the surface opposite to the light extraction surfaces 3a and 4a. Is formed. The reflective layer 7 has a laminated structure in which a plurality of SiO ₂ layers, which are insulating films, and Si _X N _Y layers (X and Y are positive integers) are periodically laminated. The material constituting the reflective layer 7 is not limited to SiO ₂ and Si _X N _Y , but is appropriately selected from insulating films such as SiON, ZrO ₂ , Al ₂ O ₃ , Nb ₂ O ₃ , and TiO _2. You can choose.

  Next, operations of the light emitting element 10 and the light emitting device according to the above-described embodiment will be described. In the light emitting element 10, when a voltage is applied in the forward direction, holes are supplied from the first electrode portion 4 and electrons are supplied from the second electrode 6. Then, electrons are injected into the active layer 12 through the first semiconductor layer 11, and holes are injected into the active layer 12 through the semiconductor layers 13 to 15. The electrons and holes injected into the active layer 12 are combined to emit light having a wavelength of about 430 nm. Here, since the surface 3a of the light emitting portion 3 is an m-plane which is a nonpolar plane, the light emitted from the active layer 12 is polarized.

  Of the polarized light generated in the active layer 12, the first polarized light L1 is emitted from the first end face 10a and travels toward the first inner wall face 1a, as shown in FIGS. Here, when the first end face 10a is a c-plane, the polarization direction of the first polarized light L1 traveling toward the first inner wall surface 1a is the a-axis direction. Most of the polarized light generated in the light-emitting element according to the embodiment in which the main growth surface is the m-plane is the first polarized light L1 having a polarization direction in the a-axis direction and traveling in the c-axis direction. The first polarized light L1 has an amount of light that is several times to about 10 times the second polarized light L2 traveling in the a-axis direction. As shown in FIG. 1C, the first polarized light L1 is reflected from the first inner wall surface 1a having a taper in the vertical direction from the mounting surface 1c, and travels in the direction opposite to the mounting surface 1c, thereby It is emitted to the outside. In order to reflect the entire first polarized light L <b> 1 on the first inner wall surface 1 a, the width of the first inner wall surface 1 a is preferably larger than the width of the first end surface 10 a of the light emitting element 10.

  Of the polarized light generated in the active layer 12, the second polarized light L2 is emitted from the second end face 10b and travels toward the second inner wall face 1b, as shown in FIGS. Here, assuming that the second end face 10b is a-plane, the polarization direction of the second polarized light L2 traveling toward the second inner wall surface 1b is the c-axis direction. As shown in FIG. 1A, the second polarized light L2 is incident on the second inner wall surface 1b at an incident angle α and reflected, thereby proceeding toward the first inner wall surface 1a. When the second polarized light L2 having the polarization direction in the c-axis direction is reflected by the second inner wall surface 1b, there is a reflection characteristic that the polarization surface is maintained with respect to the second inner wall surface 1b that is the incident surface. The two-polarized light L2 has a polarization direction in the a-axis direction that is the same as the first polarized light L1, and travels toward the first inner wall surface 1a. That is, the first polarized light L1 and the second polarized light L2 generated in the active layer 12 have almost the same polarization direction in the a-axis direction. Then, the second polarized light L2 traveling toward the first inner wall surface 1a is reflected by the first inner wall surface 1a having a taper in the vertical direction from the mounting surface 1c in the same manner as the first polarized light L1, and the second polarized light L2 on the mounting surface 1c. The light is emitted to the outside of the light emitting device by moving in the opposite direction.

  When the incident angle α is 45 degrees, the second polarized light L2 reflected by the second inner wall surface 1b goes straight toward the first inner wall surface 1a. That is, the first polarized light L1 and the second polarized light L2 generated in the active layer 12 all have a polarization direction in the a-axis direction. Therefore, the second inner wall surface 1b is preferably provided so that the incident angle of the second polarized light L2 is 45 degrees.

  Of the polarized light generated in the active layer 12, the third polarized light L3 is transmitted through the first electrode portion 4 and emitted from the light extraction surface 4a to the outside, as shown in FIGS. Of the light emitted from the active layer 12, the light traveling to the substrate 2 side passes through the first semiconductor layer 11 and the substrate 2, reaches the back surface 2 b of the substrate 2, is reflected by the reflective layer 7, and is the light extraction surface. 4a is emitted to the outside as the third polarized light L3. The third polarized light L3 emitted to the outside of the light emitting element 10 is emitted to the outside of the light emitting device as it is.

  It is preferable that the 1st end surface 10a and the 2nd end surface 10b are mirror surfaces by which the mirror-finishing process was carried out. Since the first end face 10a and the second end face 10b are mirror surfaces, the irregular reflection due to the unevenness of the surface can be suppressed and the polarization state can be maintained, so that light maintaining a high polarization ratio can be emitted to the outside.

  According to the light emitting device according to the embodiment of the present invention, the second polarized light L2 is reflected by the second inner wall surface 1b out of the first polarized light L1 and the second polarized light L2 emitted from the lateral end surface of the light emitting element. Since it can be aligned with the polarization direction of the first polarized light L1, polarized light having a high polarization ratio can be emitted to the outside. By emitting polarized light with a high polarization ratio from the light emitting device to the outside, loss due to the polarizer can be reduced.

(Modification 1)
As shown in FIG. 4, the light emitting device according to the first modification of the embodiment of the present invention has an upper base and a lower portion at two opposite sides where the first inner wall surface 1 a is parallel when viewed from the light extraction direction. It differs from the light emitting device shown in FIG. 1 in that the second inner wall surface 1b forms a trapezoid connecting the end point of the upper base and the end point of the lower base. The rest is substantially the same as the light emitting device shown in FIG.

  In order to cause the second polarized light L2 reflected by the two second inner wall surfaces 1b to be equally incident on the first end surface 10a, it is preferable to form an isosceles trapezoid in which the sizes of the two corners at the end points of the upper base are equal to each other. .

  The operation of the light-emitting element 10 and the light-emitting device according to Modification 1 will be described. In the light emitting element 10, polarized light is generated from the active layer 12 when a voltage is applied in the forward direction.

  Of the polarized light generated in the active layer 12, the first polarized light L1 is emitted from the first end face 10a and travels toward the first inner wall face 1a, as shown in FIGS. 4 (a) and 4 (c). Here, when the first end face 10a is a c-plane, the polarization direction of the first polarized light L1 traveling toward the first inner wall surface 1a is the a-axis direction. As shown in FIG. 4C, the first polarized light L1 is reflected from the first inner wall surface 1a having a taper in the vertical direction from the mounting surface 1c, and travels in the direction opposite to the mounting surface 1c, thereby It is emitted to the outside. In order to reflect the entire first polarized light L <b> 1 on the first inner wall surface 1 a, the width of the first inner wall surface 1 a is preferably larger than the width of the first end surface 10 a of the light emitting element 10.

  Of the polarized light generated in the active layer 12, the second polarized light L2 is emitted from the second end face 10b and travels toward the second inner wall face 1b as shown in FIGS. 4 (a) and 4 (b). Here, assuming that the second end face 10b is a-plane, the polarization direction of the second polarized light L2 traveling toward the second inner wall surface 1b is the c-axis direction. As shown in FIG. 4A, the second polarized light L2 is incident on the second inner wall surface 1b at an incident angle α and reflected, and thus travels toward one of the first inner wall surfaces 1a having a larger width. To do. The reflected second polarized light L2 has a polarization direction in the a-axis direction similar to the first polarized light L1, and travels toward the first inner wall surface 1a. Then, the second polarized light L2 traveling toward the first inner wall surface 1a is reflected by the first inner wall surface 1a having a taper in the vertical direction from the mounting surface 1c in the same manner as the first polarized light L1, and the second polarized light L2 on the mounting surface 1c. The light is emitted to the outside of the light emitting device by moving in the opposite direction.

(Modification 2)
As shown in FIG. 5, in the light emitting device according to the second modification of the embodiment of the present invention, a part of the second inner wall surface 1 b is formed on the second end surface 10 b of the light emitting element 10 when viewed from the light extraction direction. 1 is different from the light emitting device shown in FIG. The rest is substantially the same as the light emitting device shown in FIG.

  As shown in FIGS. 5A and 5B, the convex shape of the second inner wall surface 1b has a triangular prism shape.

  The operation of the light emitting element 10 and the light emitting device according to Modification 2 will be described. In the light emitting element 10, polarized light is generated from the active layer 12 when a voltage is applied in the forward direction.

  Of the polarized light generated in the active layer 12, the first polarized light L1 is emitted from the first end face 10a and travels toward the first inner wall face 1a, as shown in FIGS. Here, when the first end face 10a is a c-plane, the polarization direction of the first polarized light L1 traveling toward the first inner wall surface 1a is the a-axis direction. As shown in FIG. 5C, the first polarized light L1 is reflected from the first inner wall surface 1a having a taper in the vertical direction from the mounting surface 1c, and travels in the direction opposite to the mounting surface 1c, thereby It is emitted to the outside. In order to reflect the entire first polarized light L <b> 1 on the first inner wall surface 1 a, the width of the first inner wall surface 1 a is preferably larger than the width of the first end surface 10 a of the light emitting element 10.

  Of the polarized light generated in the active layer 12, the second polarized light L2 is emitted from the second end face 10b and travels toward the second inner wall face 1b, as shown in FIGS. 5 (a) and 5 (b). Here, assuming that the second end face 10b is a-plane, the polarization direction of the second polarized light L2 traveling toward the second inner wall surface 1b is the c-axis direction.

As shown in FIG. 5A, the second polarized light L2 is incident on the second inner wall surface 1b at an incident angle α and reflected to be divided into two directions, each directed toward the first inner wall surface 1a. proceed. The reflected second polarized light L2 has a polarization direction in the a-axis direction similar to the first polarized light L1, and travels toward the first inner wall surface 1a. Then, the second polarized light L2 traveling toward the first inner wall surface 1a is reflected by the first inner wall surface 1a having a taper in the vertical direction from the mounting surface 1c in the same manner as the first polarized light L1, and the second polarized light L2 on the mounting surface 1c. The light is emitted to the outside of the light emitting device by moving in the opposite direction.

(Other embodiments)
As described above, the present invention has been described according to the embodiment. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques should be apparent to those skilled in the art.

  For example, in the embodiment, as illustrated in FIG. 2, the light emitting element 10 includes the first electrode unit 4 disposed on the second semiconductor layer 15 and mesa-etching a partial region of the first semiconductor layer 11. 1, the second electrode 6 is disposed on the exposed surface of the semiconductor layer 11, but the first electrode portion 4 and the second electrode 6 may be disposed on both surfaces of the light emitting element 10. . When electrodes are arranged on both sides of the light emitting element 10, the substrate 2 must be conductive GaN.

  Thus, it should be understood that the present invention includes various embodiments and the like not described herein. Therefore, the present invention is limited only by the invention specifying matters in the scope of claims reasonable from this disclosure.

FIG. 1A is a plan view of a configuration example of a light-emitting device according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view of the light-emitting device viewed from the direction AA. ) Is a cross-sectional view of the light-emitting device viewed from the BB direction. It is sectional drawing of the structural example of the light emitting element which concerns on embodiment of this invention. It is a figure for demonstrating the unit cell of the hexagonal crystal structure. FIG. 4A is a plan view of a configuration example of a light emitting device according to Modification 1 of the embodiment of the present invention, and FIG. 4B is a cross-sectional view of the light emitting device viewed from the CC direction. FIG. 4C is a cross-sectional view of the light emitting device viewed from the DD direction. FIG. 5A is a plan view of a configuration example of a light-emitting device according to Modification 2 of the embodiment of the present invention, and FIG. 5B is a cross-sectional view of the light-emitting device viewed from the EE direction. FIG. 5C is a cross-sectional view of the light emitting device viewed from the FF direction.

Explanation of symbols

L1 ... 1st polarization L2 ... 2nd polarization L3 ... 3rd polarization 1 ... Package 1a ... 1st inner wall surface 1b ... 2nd inner wall surface 1c ... Mounting surface 2 ... Board | substrate 3 ... Light emission part 3a, 4a ... Light extraction surface 4 ... 1st electrode part 5 ... Connection part 6 ... 2nd electrode 7 ... Reflective layer 10 ... Light emitting element 10a ... 1st end surface 10b ... 2nd end surface 11 ... 1st semiconductor layer 12 ... Active layer 12a ... Growth main surface 13 ... Final barrier Layer 14 ... Electron blocking layer 15 ... Second semiconductor layer 20 ... Adhesive

Claims (5)

A light emitting element that emits the first polarized light and the second polarized light from the first end face and the second end face, respectively;
And a package having a second inner wall surface that reflects the second polarized light toward a first inner wall surface that faces the first end surface in parallel with the light-emitting element. apparatus.   The light emitting device according to claim 1, wherein the first inner wall surface has a taper in a direction perpendicular to the mounting surface.   The second inner wall surface is provided so that an incident angle of the second polarized light is 45 degrees so as to reflect the second polarized light toward the first inner wall surface. 3. The light emitting device according to 1 or 2.   The light emitting device according to claim 1, wherein the first inner wall surface and the second inner wall surface are mirror surfaces.   The light emitting element includes an active layer made of a group III nitride semiconductor having a nonpolar plane or a semipolar plane as a growth main surface, and the first end surface and the second end of the active layer orthogonal to the growth main surface. The light-emitting device according to claim 1, wherein the first polarized light and the second polarized light are generated from an end surface.

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