JP2012244028A - Light-emitting device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device which emits light efficiently and features a large interval between plural emission surfaces.SOLUTION: A first gain region 160 of a light-emitting device 100 is inclined toward one side relative to a perpendicular line P of a first plane 130 to join the first plane 130, while a second gain region 170 is inclined toward the other side relative to the perpendicular line 170 to join the first plane 130, where a first end face 180 on the first plane 130 side of the first gain region 160 and a third end face 184 on the first plane 130 side of the second gain region 170 overlap on the first plane 130, and the first gain region 160 and the second gain region 170 join a second plane 132 at the same angle of inclination. A first gain part 162 and a second gain part 172 formed in shape of a curved line and a third gain part 164 and a fourth gain part 174 formed in shape of a linear line are connected together via a fifth gain part 166 and a sixth gain part 176, and have a first connection part 140 and a second connection part 150 where the refractive index of an insulation layer 116 at places in contact with the fifth gain part 166 and the sixth gain part 176 is in slope form or stepped form.

Description

  The present invention relates to a light emitting device and a projector.

  A super luminescent diode (hereinafter also referred to as “SLD”) is incoherent like a normal light emitting diode and has a broad spectrum shape, but has a single optical output characteristic similar to that of a semiconductor laser. This is a semiconductor light emitting device capable of obtaining an output up to about several hundreds mW.

  The SLD is used as a light source for a projector, for example. In order to realize a small and high brightness projector, it is necessary to use a light source having a large light output and a small etendue. For this purpose, it is desirable that light emitted from a plurality of gain regions travel in the same direction. In Patent Document 1, by combining a gain region having a linear shape and a gain region having an arc shape, the light emitted from the exit surfaces of the two gain regions travels in the same direction. ing.

JP 2010-192603 A

  By the way, in order to reduce the loss of the optical system and reduce the number of parts, there has been proposed a projector that employs a system in which an SLD is arranged directly under a light valve, and condensing and uniform illumination are simultaneously performed using a lens array. In such a type of projector, it is necessary to arrange the exit surface in accordance with the distance between the lens arrays.

  In the technique described in Patent Document 1, as a method of forming a large interval between the two exit surfaces in accordance with the lens array, for example, it is considered that the linear gain region is largely inclined with respect to the normal of the exit surface. It is done. However, in such a method, the incident angle of the light generated in the linear gain region with respect to the exit surface is increased, and the radiation pattern may be deteriorated. As a result, it may be difficult to uniformly illuminate the light valve.

  Further, as another method of forming a large interval between the two exit surfaces, it is conceivable to increase the total length of the gain region. However, if the total length of the gain region is increased, generally, the output can be increased, but a large amount of current must be passed in order to obtain the inversion distribution. If not used, high efficiency cannot be achieved. That is, the light emission efficiency is reduced below a predetermined light output. When the light emission efficiency deteriorates, it becomes difficult to exhaust heat from the light emitting device, and thus, for example, it becomes difficult to realize a small projector. Furthermore, when the total length of the gain region is increased, the area of the entire element is increased, and problems such as waste of resources and increase in manufacturing costs arise.

  One of the objects according to some aspects of the present invention is to provide a light-emitting device that has a good radiation pattern, can be made small and high in output, and can be formed with a large interval between a plurality of emission surfaces. is there. Another object of some aspects of the present invention is to provide a projector having the light-emitting device.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A light emitting device according to this application example includes a first layer, a second layer, a third layer sandwiched between the first layer and the second layer, and the third layer of the second layer. A laminate having a fourth layer formed on the side opposite to the side; a first electrode electrically connected to the first layer; and a fourth electrode electrically connected to the second layer; The third layer includes a first gain region and a second gain region in which light is generated and light is guided, as viewed from the stacking direction of the stacked body, The shapes of the first gain region and the second gain region are the same as the contact surface between the fourth layer and the second electrode, and the first layer and the second layer are formed in the first gain region. And the fourth layer is a layer in ohmic contact with the second electrode, and the third layer is a layer for suppressing light leakage generated in the second gain region. The first surface has a first surface and a second surface facing each other, and the reflectance of the first surface is the reflection of the second surface in a wavelength band of light generated in the first gain region and the second gain region. The first gain region and the second gain region are provided from the first surface to the second surface, and the first gain region is the first gain region when viewed from the stacking direction of the stacked body. The second gain region is inclined to the other side with respect to the vertical line when viewed from the stacking direction of the stacked body. The first gain region and the second gain region are connected to the second surface with the same inclination when viewed from the stacking direction of the stacked body, and the first gain region and the second gain region are connected to the second surface. The end surface on the first surface side and the end surface on the first surface side of the second gain region overlap each other on the first surface, The first gain region includes a first gain portion having a first curvature, a linear third gain portion, the first gain portion, and the third gain portion as viewed from the stacking direction of the stacked body. A second gain region having a second curvature as viewed from the stacking direction of the stacked body, and a linear fourth gain. And a sixth gain portion connected to the second gain portion and the fourth gain portion, wherein the first gain region and the second gain region are viewed from the stacking direction of the stacked body. The effective refractive index of the insulating layer that is sandwiched between the insulating layers and is in contact with the first gain portion and the second gain portion is the first refractive index, and is effective in contact with the third gain portion and the fourth gain portion. When the refractive index is the second refractive index, the refractive index in contact with the fifth gain portion and the sixth gain portion is As the first gain portion and the third gain portion approach the second gain portion and the fourth gain portion, the first refractive index is switched to the second refractive index stepwise.

  According to this application example, the first electrode and the second electrode apply a voltage to the stacked body. The fourth layer is in ohmic contact with the second electrode, and the third layer generates light and guides the light. The first layer and the second layer suppress light leakage. Light is generated and transmitted by the laminate of the first to fourth layers. The first gain portion in the first gain region and the second gain portion in the second gain region overlap each other on the first surface with a first curvature and a second curvature, respectively. Therefore, without increasing the incident angle of the light generated in the first gain region and the second gain region with respect to the first surface, the end surface on the second surface side of the first gain region and the second surface of the second gain region The distance from the side end face (the distance between the exit faces) can be increased. Thereby, it can suppress that the radiation pattern of the emitted light is distorted.

  Further, according to this application example, the first gain portion in the first gain region and the second gain portion in the second gain region overlap each other on the first surface with the first curvature and the second curvature. Therefore, when the interval between the emission surfaces is increased, the overall length of the gain region can be shortened compared to an example using a gain region that is linear from the first surface to the second surface. Therefore, it is not necessary to flow a large amount of current, and power consumption can be suppressed. Furthermore, since it is not necessary to increase the overall length of the gain region, the entire apparatus can be reduced in size. Therefore, resources are not wasted and manufacturing costs can be reduced.

  Further, according to this application example, the refractive index of the insulating layer in contact with the fifth gain portion and the sixth gain portion approaches the second gain portion and the fourth gain portion from the first gain portion and the third gain portion. Accordingly, the first refractive index is switched to the second refractive index stepwise. Thus, the reflectance generated at the connection portion between the first gain portion and the third gain portion in the first gain region and the reflectance generated at the connection portion between the second gain portion and the fourth gain portion in the second gain region are obtained. Can be suppressed. Thereby, the light generated in the first gain region and the second gain region is connected to the first gain portion and the third gain portion in the first gain region, and the second gain portion and the fourth gain in the second gain region. Multiple reflection at the connecting portion with the gain portion can be suppressed. Therefore, the light generated in the first gain region and the second gain region can be efficiently extracted outside.

  As a result, the light emitting device is highly efficient and has a good radiation pattern, and the distance between the emission surfaces can be increased while downsizing.

  Application Example 2 A light emitting device according to this application example includes a first layer, a second layer, a third layer sandwiched between the first layer and the second layer, and the third layer of the second layer. A laminate having a fourth layer formed on the side opposite to the side; a first electrode electrically connected to the first layer; and a fourth electrode electrically connected to the second layer; The third layer includes a first gain region and a second gain region in which light is generated and light is guided, as viewed from the stacking direction of the stacked body, The shapes of the first gain region and the second gain region are the same as the contact surface between the fourth layer and the second electrode, and the first layer and the second layer are formed in the first gain region. And the fourth layer is a layer in ohmic contact with the second electrode, and the third layer is a layer for suppressing light leakage generated in the second gain region. The first surface has a first surface and a second surface facing each other, and the reflectance of the first surface is the reflection of the second surface in a wavelength band of light generated in the first gain region and the second gain region. The first gain region and the second gain region are provided from the first surface to the second surface, and the first gain region is the first gain region when viewed from the stacking direction of the stacked body. The second gain region is inclined to the other side with respect to the vertical line when viewed from the stacking direction of the stacked body. The first gain region and the second gain region are connected to the second surface with the same inclination when viewed from the stacking direction of the stacked body, and the first gain region and the second gain region are connected to the second surface. The end surface on the first surface side and the end surface on the first surface side of the second gain region overlap each other on the first surface, The first gain region includes a first gain portion having a first curvature, a linear third gain portion, the first gain portion, and the third gain portion as viewed from the stacking direction of the stacked body. A second gain region having a second curvature as viewed from the stacking direction of the stacked body, and a linear fourth gain. And a sixth gain portion connected to the second gain portion and the fourth gain portion, wherein the first gain region and the second gain region are viewed from the stacking direction of the stacked body. The effective refractive index of the insulating layer that is sandwiched between the insulating layers and is in contact with the first gain portion and the second gain portion is the first refractive index, and is effective in contact with the third gain portion and the fourth gain portion. When the refractive index is the second refractive index, the refractive index in contact with the fifth gain portion and the sixth gain portion is As the first gain portion and the third gain portion approach the second gain portion and the fourth gain portion, the first refractive index is continuously switched to the second refractive index.

  According to this application example, the first gain portion in the first gain region and the second gain portion in the second gain region overlap each other on the first surface with the first curvature and the second curvature. The end face of the first gain region provided on the second surface and the second surface provided on the second surface without increasing the incident angle of the light generated in the first gain region and the second gain region with respect to the first surface. It is possible to increase the distance between the end face of the gain region (the distance between the exit faces). Thereby, it can suppress that the radiation pattern of the emitted light is distorted.

  Further, according to this application example, the first gain portion in the first gain region and the second gain portion in the second gain region overlap each other on the first surface with the first curvature and the second curvature. Therefore, when the interval between the emission surfaces is increased, the overall length of the gain region can be shortened compared to an example using a gain region that is linear from the first surface to the second surface. Therefore, it is not necessary to flow a large amount of current, and power consumption can be suppressed. Furthermore, since it is not necessary to increase the overall length of the gain region, the entire apparatus can be reduced in size. Therefore, resources are not wasted and manufacturing costs can be reduced.

  Further, according to this application example, as the refractive index of the place in contact with the fifth gain portion and the sixth gain portion approaches the second gain portion and the fourth gain portion from the first gain portion and the third gain portion, The first refractive index is continuously switched to the second refractive index. Thus, the reflectance generated at the connection portion between the first gain portion and the third gain portion in the first gain region and the reflectance generated at the connection portion between the second gain portion and the fourth gain portion in the second gain region are obtained. Can be suppressed. Thereby, the light generated in the first gain region and the second gain region is connected to the first gain portion and the third gain portion in the first gain region, and the second gain portion and the fourth gain in the second gain region. Multiple reflection at the connecting portion with the gain portion can be suppressed. Therefore, the light generated in the first gain region and the second gain region can be efficiently extracted outside.

  As a result, the light emitting device is highly efficient and has a good radiation pattern, and the distance between the emission surfaces can be increased while downsizing.

  Application Example 3 In the light emitting device according to the application example described above, the first gain region is inclined at a first angle with respect to the perpendicular to be connected to the first surface, and the second gain region is the perpendicular. It is preferable that the first angle and the second angle are equal to or greater than the critical angle and have the same size.

  According to this application example, the first surface can totally reflect light generated in the first gain region and the second gain region. Therefore, light loss on the first surface can be suppressed, and light can be reflected efficiently.

  Application Example 4 In the light emitting device according to the application example described above, the first gain region includes a seventh gain portion that is linearly provided from the first surface to the first gain portion. The 2 gain region preferably includes an eighth gain portion that is linearly provided from the first surface to the second gain portion.

  According to this application example, the light generated in the first gain region and reflected on the first surface is more reliably incident on the second gain region, and the light generated in the second gain region and reflected on the first surface is It is possible to enter the first gain region more reliably.

  Application Example 5 In the light emitting device according to the application example described above, it is preferable that the first gain portion and the second gain portion have an arc shape when viewed from the stacking direction of the stacked body.

  According to this application example, since the first gain portion and the second gain portion have an arc shape, transmission can be performed with less internal reflection of light. As a result, the radiation pattern is good, and the distance between the exit surfaces can be increased while reducing the size.

  In the description according to the present invention, the phrase “electrically connected” is used as, for example, another specific member (hereinafter “electrically connected” to “specific member (hereinafter referred to as“ A member ”)”. B member "))" and the like. In the description according to the present invention, in the case of this example, the case where the A member and the B member are in direct contact and electrically connected, and the A member and the B member are the other members. The term “electrically connected” is used as a case where the case where the terminals are electrically connected to each other is included.

  Application Example 6 In the light emitting device according to the application example described above, it is preferable that the first surface is a cleavage plane.

  According to this application example, for example, the first surface can be formed with higher accuracy than when a surface that is not a cleavage plane is formed by a photolithography technique and an etching technique. Therefore, light scattering at the end face can be reduced. As a result, light loss on the first surface can be suppressed, and light can be efficiently reflected.

  Application Example 7 A projector according to this application example includes the light-emitting device described above, a microlens that collects light emitted from the light-emitting device, and light collected by the microlens as image information. And a projection device that projects an image formed by the light modulation device.

  According to this application example, the microlens condenses the light emitted from the light emitting device. The light modulation device modulates the collected light. The projection device projects the modulated light. The light emitting device has high efficiency and good radiation pattern, and can increase the interval between the emission surfaces while reducing the size. Therefore, the optical axis can be easily aligned using the microlens. As a result, the projector according to this application example can be a projector including a light emitting device that emits uniform light efficiently.

1 is a schematic plan view showing a light emitting device according to Embodiment 1. FIG. FIG. 2 is a schematic cross-sectional view of a main part showing the light emitting device according to the first embodiment. FIG. 2 is a schematic cross-sectional view of a main part showing the light emitting device according to the first embodiment. FIG. 2 is a schematic cross-sectional view of a main part showing the light emitting device according to the first embodiment. 3 is an effective refractive index profile of a gain region according to the first embodiment. FIG. 3 is a schematic diagram for explaining a method for manufacturing the light emitting device according to the first embodiment. FIG. 3 is a schematic diagram for explaining a method for manufacturing the light emitting device according to the first embodiment. FIG. 3 is a schematic diagram for explaining a method for manufacturing the light emitting device according to the first embodiment. FIG. 3 is a schematic plan view showing a structure of a light emitting device according to a second embodiment. FIG. 4 is a cross-sectional view of a main part of a light emitting device according to a second embodiment. The effective refractive index profile in the light-emitting device concerning Embodiment 2. FIG. FIG. 4 is a schematic diagram for explaining a method for forming a light emitting device according to a second embodiment. FIG. 4 is a schematic diagram for explaining a method for forming a light emitting device according to a second embodiment. FIG. 4 is a schematic diagram for explaining a method for forming a light emitting device according to a second embodiment. FIG. 6 is a schematic plan view showing the structure of a light emitting device according to a third embodiment. FIG. 6 is a schematic plan view illustrating a structure of a light emitting device according to a fourth embodiment. FIG. 6 is a schematic diagram illustrating a structure of a projector according to a fifth embodiment. FIG. 10 is a schematic diagram illustrating a main part of a configuration of a projector according to a fifth embodiment. FIG. 10 is a schematic diagram illustrating a light source of a projector according to a fifth embodiment. FIG. 6 is a schematic side sectional view showing a light source of a projector according to a fifth embodiment. FIG. 10 is a schematic side sectional view showing a modification of the light source of the projector according to the fifth embodiment. FIG. 10 is a schematic side sectional view showing a modification of the light source of the projector according to the fifth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is made different from the actual scale so that each layer and each member can be recognized.

(Embodiment 1)
1. First, the light emitting device according to the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic plan view showing the light emitting device according to the present embodiment. FIG. 2 is a schematic cross-sectional view showing a main part of the light emitting device according to the present embodiment, and is a cross-sectional view taken along the line II-II ′ of FIG. FIG. 3 is a schematic cross-sectional view of a main part of the light emitting device according to the present embodiment, and is a cross-sectional view taken along the line III-III ′ of FIG. FIG. 4 is a schematic cross-sectional view of a main part showing the light emitting device according to the present embodiment, and is a cross-sectional view taken along the line IV-IV ′ of FIG. In FIG. 1, the second electrode 114 is not shown for convenience.

  Hereinafter, a case where the light emitting device 100 is an InGaAlP-based (red) SLD will be described. Unlike a semiconductor laser, an SLD can prevent laser oscillation by suppressing the formation of a resonator due to end face reflection. Therefore, speckle noise can be reduced.

  As shown in FIGS. 1, 2, 3, and 4, the light emitting device 100 may include a stacked body 120, a first electrode 112, and a second electrode 114.

  The stacked body 120 includes a substrate 102, a first cladding layer 104 as a first layer, an active layer 106 as a third layer, a second cladding layer 108 as a second layer, a contact layer 110 as a fourth layer, and an insulating layer. 116. Although the shape of the laminated body 120 is not specifically limited, For example, a rectangular parallelepiped or a cube can be adopted.

  As the substrate 102, for example, a first conductivity type (for example, n-type) GaAs substrate or the like can be used. The first cladding layer 104 is formed on the substrate 102. As the first cladding layer 104, for example, an n-type InGaAlP layer or the like can be used. The second cladding layer 108 is made of the same material as the first cladding layer 104. Although not shown, a buffer layer may be formed between the substrate 102 and the first cladding layer 104. As the buffer layer, for example, an n-type GaAs layer, an AlGaAs layer, an InGaP layer, or the like can be used. The buffer layer can improve the crystallinity of the layer formed thereabove.

  The active layer 106 is formed on the first cladding layer 104. The active layer 106 is sandwiched between the first cladding layer 104 and the second cladding layer 108. The active layer 106 has, for example, a multiple quantum well (MQW) structure in which three quantum well structures each composed of an InGaP well layer and an InGaAlP barrier layer are stacked.

  The first surface 130, the second surface 132, the third surface 134, and the fourth surface 136, which are side surfaces of the light emitting device 100, are flat surfaces. The first surface 130 and the second surface 132 face each other and are parallel in the illustrated example. The third surface 134 and the fourth surface 136 are surfaces that intersect and connect to the first surface 130 and the second surface 132, face each other, and are parallel in the illustrated example.

  The first surface 130 is a cleavage surface formed by cleavage. The formation method is not particularly limited as long as the second surface 132 faces the first surface 130. For example, the second surface 132 can also be easily made to face the first surface 130 by using a cleavage surface. .

  A part of the active layer 106 constitutes a first gain region 160 and a second gain region 170. The first gain region 160 and the second gain region 170 can generate light, and the light can be guided through the first gain region 160 and the second gain region 170 while receiving gain.

  The first gain region 160 and the second gain region 170 are prismatic and are provided from the first surface 130 to the second surface 132 as shown in FIG. The first gain region 160 has a first end surface 180 provided on the first surface 130 and a second end surface 182 provided on the second surface 132. The second gain region 170 has a third end surface 184 provided on the first surface 130 and a fourth end surface 186 provided on the second surface 132.

  The first end surface 180 of the first gain region 160 and the third end surface 184 of the second gain region 170 overlap on the first surface 130. In the illustrated example, the first end surface 180 and the third end surface 184 completely overlap. On the other hand, the second end surface 182 of the first gain region 160 and the fourth end surface 186 of the second gain region 170 are separated by a distance D on the second surface 132.

  As shown in FIG. 1, the first gain region 160 is inclined to one side (the third surface 134 side) with respect to the perpendicular P of the first surface 130 in a plan view as viewed from the stacking direction of the stacked body 120. It is connected to the surface 130. More specifically, the first gain region 160 is connected to the first surface 130 at a first angle α1 with respect to the perpendicular P. The second gain region 170 is connected to the first surface 130 while being inclined to the other side (the fourth surface 136 side) with respect to the perpendicular P in plan view. More specifically, the second gain region 170 is connected to the first surface 130 at a second angle α2 with respect to the perpendicular P.

  The first angle α1 is an incident angle of the light generated in the first gain region 160 with respect to the first surface 130. The second angle α2 is an incident angle of the light generated in the second gain region 170 with respect to the first surface 130. The first angle α1 and the second angle α2 are acute angles having the same size and are equal to or greater than the critical angle. Accordingly, the first surface 130 can totally reflect light generated in the first gain region 160 and the second gain region 170.

  The first gain region 160 and the second gain region 170 are inclined in the same direction and connected to the second surface 132. More specifically, the first gain region 160 and the second gain region 170 are connected to the second surface 132 by being inclined at the third angle β with respect to the perpendicular P. The third angle β may be 0 ° as long as it is an acute angle and smaller than the critical angle. Thereby, the emitted light 20 emitted from the second end surface 182 of the first gain region 160 and the emitted light 22 emitted from the fourth end surface 186 of the second gain region 170 can travel in the same direction. . The second end surface 182 and the fourth end surface 186 are emission surfaces. The third angle β is an incident angle of the light generated in the first gain region 160 and the second gain region 170 with respect to the second surface 132.

  As described above, the light emitting device 100 is set such that the first angle α1 and the second angle α2 are equal to or greater than the critical angle, and the third angle β is smaller than the critical angle. Thereby, the reflectance of the first surface 130 can be made higher than the reflectance of the second surface 132 in the wavelength band of light generated in the first gain region 160 and the second gain region 170. That is, the first surface 130 can be a reflective surface, and the second surface 132 can be an exit surface.

Although not shown, for example, the first surface 130 may be covered with a reflection film, and the second surface 132 may be covered with an antireflection film. Thereby, the reflectance of the first surface 130 can be made higher than the reflectance of the second surface 132 in the wavelength band of light generated in the first gain region 160 and the second gain region 170. As the reflection film and the antireflection film, for example, a SiO ₂ layer, a Ta ₂ O ₅ layer, an Al ₂ O ₃ layer, a TiN layer, a TiO ₂ layer, a SiON layer, a SiN layer, or a multilayer film thereof may be used. it can.

  Furthermore, the third angle β can be at least one of greater than 0 ° and smaller than the critical angle, or whether the second surface 132 is covered with an antireflection film. Thereby, light generated in the first gain region 160 and the second gain region 170 between the second end surface 182 and the fourth end surface 186 can be prevented from being subjected to multiple reflection. As a result, since a direct resonator cannot be formed, laser oscillation of light generated in the first gain region 160 and the second gain region 170 can be suppressed or prevented.

  The first gain region 160 has a first gain portion 162. Similarly, the second gain region 170 has a second gain portion 172. The first gain portion 162 and the second gain portion 172 are portions connected to the first surface 130. That is, the first gain portion 162 constitutes the first end surface 180 of the first gain region 160, and the second gain portion 172 constitutes the third end surface 184 of the second gain region 170.

  The first gain portion 162 has a shape having a first curvature in a plan view viewed from the stacking direction of the stacked body 120. The second gain portion 172 has a shape having a second curvature in plan view. The first curvature and the second curvature may be the same value or different values. In the illustrated example, the first gain portion 162 and the second gain portion 172 have an arc shape and the same radius of curvature. The arc length of the second gain portion 172 may be smaller than the arc length of the first gain portion 162. For example, the first gain portion 162 has an arc shape centered on the point O1, and the second gain portion 172 has an arc shape centered on the point O2. The point O1 is located on the fourth surface 136 side with respect to the perpendicular P passing through the first end surface 180 and the third end surface 184, and the point O2 is located on the third surface 134 side with respect to the perpendicular P. Yes.

  The effective refractive index of the vertical section of the stacked body 120 including the first gain portion 162 and the second gain portion 172 is referred to as the effective refractive index of the first gain portion 162 and the second gain portion 172. The effective refractive index in the vertical section of the stacked body 120 that avoids the first gain region 160 and the second gain region 170 is referred to as the effective refractive index at a position that avoids the first gain region 160 and the second gain region 170. At this time, the light generated in the first gain region 160 and the second gain region 170 avoids the effective refractive index of the first gain portion 162 and the second gain portion 172, and the first gain region 160 and the second gain region 170. Due to the difference from the effective refractive index at the position, the first gain portion 162 and the second gain portion 172 having an arc shape can travel.

  The effective refractive index indicates an effective refractive index for light propagating through the first gain region 160 and the second gain region 170. The effective refractive index is also referred to as the effective refractive index. When the phase coefficient is β and the free space wavenumber is k0, the effective refractive index is defined by β / k0.

  The radii of curvature of the first gain portion 162 and the second gain portion 172 are the effective refractive indexes of the first gain portion 162 and the second gain portion 172, and the effective positions at positions avoiding the first gain region 160 and the second gain region 170. It is set according to the difference between the refractive index. Although the curvature radius of the 1st gain part 162 and the 2nd gain part 172 is not specifically limited, In this embodiment, it is 800 micrometers or more, for example. When the curvature radii of the first gain portion 162 and the second gain portion 172 are less than 800 μm, the light in the first gain portion 162 and the second gain portion 172 may not be guided efficiently. Preferably, the radius of curvature of the first gain portion 162 and the second gain portion 172 is about 1600 μm. Accordingly, the light in the first gain portion 162 and the second gain portion 172 can be efficiently guided without unnecessarily increasing the entire light emitting device 100.

  The first gain region 160 can further include a third gain portion 164. Similarly, the second gain region 170 can further include a fourth gain portion 174. The third gain portion 164 is linearly provided from the first gain portion 162 to the second surface 132. That is, the third gain portion 164 constitutes the second end face 182 of the first gain region 160. The third gain portion 164 is smoothly connected to the arc-shaped first gain portion 162. For example, the third gain portion 164 is provided so as to be parallel to a tangent at a point on the boundary between the first gain portion 162 and the third gain portion 164. The third gain portion 164 is inclined with respect to the perpendicular P by a third angle β (including 0 °).

  The fourth gain portion 174 is linearly provided from the second gain portion 172 to the second surface 132. That is, the fourth gain portion 174 constitutes the fourth end face 186 of the second gain region 170. The fourth gain portion 174 is smoothly connected to the arc-shaped second gain portion 172. It is preferable that the tangent line of the second gain part 172 and the tangent line of the fourth gain part 174 are parallel to each other at a point on the boundary between the second gain part 172 and the fourth gain part 174. The fourth gain portion 174 is inclined with respect to the perpendicular P by a third angle β (including 0 °).

  The third gain portion 164 and the fourth gain portion 174 are parallel to each other. The length of the fourth gain portion 174 is not particularly limited, but may be larger than the length of the third gain portion 164.

  The first gain region 160 can further include a fifth gain portion 166. Further, the first connection portion 140 is formed so as to sandwich the fifth gain portion 166. Similarly, the second gain region 170 can further include a sixth gain portion 176. The second connection portion 150 is formed so as to sandwich the sixth gain portion 176.

  The fifth gain portion 166 can be formed by a part of the first gain portion 162 and a part of the third gain portion 164. In the present embodiment, the fifth gain portion 166 is formed by both a part of the first gain portion 162 and a part of the third gain portion 164, but may be formed by either one. .

  The sixth gain portion 176 can be formed by part of the second gain portion 172 and part of the fourth gain portion 174. In the present embodiment, an example in which the sixth gain portion 176 is formed by both a part of the second gain portion 172 and a part of the fourth gain portion 174 has been shown, but may be formed by either one. .

  As shown in FIG. 4, both sides of the first gain portion 162 and the second gain portion 172 are sandwiched between the insulating layers 116, and both sides of the third gain portion 164 and the fourth gain portion 174 are the stacked body 120. Yes. Then, both sides of the first connection portion 140 and the second connection portion 150 are portions that are switched from the insulating layer 116 to the stacked body 120.

  A boundary position between the first gain portion 162 and the second gain portion 172 and the first connection portion 140 and the second connection portion 150 is defined as a position X1. A boundary position between the first connection portion 140 and the second connection portion 150 and the third gain portion 164 and the fourth gain portion 174 is defined as a position X3. In the first connection portion 140 and the second connection portion 150, the insulating layer 116 and the stacked body 120 are joined in a stepped manner. And the starting position of the level | step difference formed between the position X1 and the position X3 is set to the position X2. That is, the positions X1 to X3 are arranged side by side from the first surface 130 side toward the second surface 132 side.

  The lowermost position of the staircase shape in the thickness direction of the substrate 102 is defined as a position Y0. The position of the uppermost part of the staircase shape is defined as position Y3. Locations obtained by equally dividing the position Y0 and the position Y3 into three are defined as a position Y1 and a position Y2. Therefore, the positions Y0 to Y3 are equally spaced in the thickness direction of the substrate 102. The step at position X1 is from position Y0 to position Y1, and the step at position X2 is from position Y1 to position Y2. The step at position X3 is from position Y2 to position Y3.

  The cross-sectional shapes of the first connection portion 140 and the second connection portion 150 are stepped shapes with the upper surface 113 as the uppermost portion and the columnar portion 111 formed, for example, with the layer exposed by a technique such as etching as the lowermost portion. There is no. In this embodiment, an example in which a three-step staircase shape is formed is shown, but the number of steps can be arbitrarily set to two or more. In the present embodiment, an example in which the middle surface of the substrate 102 forms the lowermost portion has been described. However, for example, the middle surface of the first cladding layer 104 may be the lowermost portion having a step shape. In addition, the surface where the substrate 102 and the first clad layer 104 are in contact with each other may be the bottom of the staircase shape.

  In addition, here, the interval between the position X1 and the position X2 and the interval between the position X2 and the position X3 may be equal or different from each other.

  The steps per step of the staircase shape may be provided with an arbitrary number of steps between the uppermost portion formed of the upper surface 113 and the lowermost portion formed in the middle of an arbitrary layer. In this embodiment, the steps in the step shape, that is, the interval between the position Y0 and the position Y1, the interval between the position Y1 and the position Y2, and the interval between the position Y2 and the position Y3 are all set to the same interval, but are set to different intervals. You may do it. You may set to the conditions from which the emitted light 20 and the emitted light 22 inject | emit efficiently.

  The first connection portion 140 is formed at a position adjacent to the connection portion between the first gain portion 162 and the third gain portion 164. The first connection portion 140 can be formed to include either a position adjacent to the first gain portion 162 or a position adjacent to the third gain portion 164. Further, it is desirable that the first connection portion 140 is formed to have the same stepped cross section on both the third surface 134 side and the fourth surface 136 side with the first gain region 160 interposed therebetween. Thereby, the coupling efficiency between the first gain portion 162 and the third gain portion 164 can be further increased.

  Similarly, the second connection portion 150 is formed at a position adjacent to the connection portion between the second gain portion 172 and the fourth gain portion 174. The second connection portion 150 can be formed to include either a position adjacent to the second gain portion 172 or a position adjacent to the fourth gain portion 174. The second connection portion 150 is preferably formed to have the same stepped cross section on both the third surface 134 side and the fourth surface 136 side with the second gain region 170 interposed therebetween. Thereby, the coupling efficiency between the second gain portion 172 and the fourth gain portion 174 can be further increased.

  FIG. 5 is an effective refractive index profile of the gain region along the line V-V ′ in FIG. 1. In FIG. 5, the horizontal axis indicates the position, and the positions X1, X2, and X3 indicate the same positions as the positions X1, X2, and X3 shown in FIG. The vertical axis represents the effective refractive index, and the effective refractive index on the upper side in the figure is high. The refractive index n1 is the effective refractive index of the first gain portion 162 and the second gain portion 172, and the refractive index n3 is the effective refractive index of the third gain portion 164 and the fourth gain portion 174. The refractive index n12 is an effective refractive index between the position X1 and the position X2, and the refractive index n23 is an effective refractive index between the position X2 and the position X3.

  As shown in FIG. 4, when the cross-sectional shape of the first connection portion 140 is formed in a staircase shape as described above, the effective refractive index profile of the fifth gain portion 166 has positions X1, X2 as shown in FIG. , It will be roughly stepped with X3 as the boundary. The insulating layer 116 has a lower dielectric constant than the first cladding layer 104, the active layer 106, and the second cladding layer 108. As the position shifts to the position X1, the position X2, and the position X3, the proportion of the insulating layer 116 that occupies the side surface of the first gain region 160 decreases. The smaller the proportion of the side surface of the first gain region 160 occupied by the insulating layer 116, the greater the effective refractive index. The same applies to the second gain region 170.

  That is, the magnitude relationship between the effective refractive indexes n1, n12, n23, and n3 is n1 <n12 <n23 <n3. In this embodiment, the refractive index difference between the refractive index n12 and the refractive index n1, the refractive index difference between the refractive index n23 and the refractive index n12, and the refractive index difference between the refractive index n3 and the refractive index n23 are equal to each other. Set to. However, the present invention is not limited to this, and the difference in refractive index can be arbitrarily determined by taking a staircase structure at the connection portion or by selecting a constituent material of the stacked body 120.

  In the first connection portion 140, the effective refractive index increases as the first gain portion 162 side shifts to the third gain portion 164 side. In the first gain portion 162, the columnar portion 111 has an arc shape, and light travels by reflecting the side surface of the first gain region 160. And in the 1st connection part 140, the 1st gain area | region 160 switches from circular arc shape to linear form. At this time, when the effective refractive index is suddenly switched, the rate at which light deviates from the side surface of the first gain region 160 increases. On the other hand, it is possible to prevent light from deviating from the side surface of the first gain region 160 by switching the effective refractive index stepwise.

  That is, by providing the first connection portion 140, reflection loss at the interface between the first gain portion 162 and the third gain portion 164 that occurs when light is guided from the first gain portion 162 to the third gain portion 164. Can be reduced. Similarly, by providing the second connection portion 150, an interface between the second gain portion 172 and the fourth gain portion 174 that occurs when light is guided from the second gain portion 172 to the fourth gain portion 174. Can reduce reflection loss. As a result, light can be efficiently emitted from the second end surface 182 and the fourth end surface 186.

  As shown in FIG. 2, the second cladding layer 108 is formed on the active layer 106. As the second cladding layer 108, for example, a second conductivity type (for example, p-type) InGaAlP layer or the like can be used.

  For example, the p-type second cladding layer 108, the active layer 106 not doped with impurities, and the n-type first cladding layer 104 constitute a pin diode. Each of the first cladding layer 104 and the second cladding layer 108 is a layer having a larger forbidden band width and a smaller refractive index than the active layer 106. The active layer 106 has a function of generating light and guiding it while amplifying the light. The first cladding layer 104 and the second cladding layer 108 have a function of confining injected carriers (electrons and holes) and light (a function of suppressing light leakage) with the active layer 106 interposed therebetween.

  In the light emitting device 100, when a forward bias voltage of a pin diode is applied between the first electrode 112 and the second electrode 114, electrons and holes are generated in the first gain region 160 and the second gain region 170 of the active layer 106. Recombination occurs. This recombination causes light emission. With this generated light as a starting point, stimulated emission occurs in a chain, and the light intensity is amplified in the first gain region 160 and the second gain region 170.

  For example, as shown in FIG. 1, a part of the light 10 generated in the first gain region 160 is amplified in the first gain region 160 and then reflected on the first surface 130 to be reflected in the second gain region 170. The light is emitted from the fourth end face 186 as the emitted light 22, but the light intensity is amplified also in the second gain region 170 after reflection. Similarly, part of the light generated in the second gain region 170 is amplified in the second gain region 170, then reflected on the first surface 130, and emitted from the second end surface 182 of the first gain region 160. 20 is emitted, but the light intensity is also amplified in the first gain region 160 after reflection.

  Note that some of the light generated in the first gain region 160 is directly emitted from the second end face 182 as the emitted light 20. Similarly, some of the light generated in the second gain region 170 is directly emitted from the fourth end face 186 as the emitted light 22. These lights are similarly amplified in the first gain region 160 and the second gain region 170.

  As shown in FIGS. 2 and 3, the contact layer 110 is formed on the second cladding layer 108. That is, the contact layer 110 is formed on the side opposite to the active layer 106 side of the second cladding layer 108. The contact layer 110 can be in ohmic contact with the second electrode 114. It can be said that the upper surface 113 of the contact layer 110 is a contact surface between the contact layer 110 and the second electrode 114. As the contact layer 110, for example, a p-type GaAs layer or the like can be used.

  As shown in FIG. 2, the columnar portions 111 of the first gain portion 162 and the second gain portion 172 include a contact layer 110, a second cladding layer 108, an active layer 106, a first cladding layer 104, and a substrate 102. And a part of it. That is, in the first gain portion 162 and the second gain portion 172, it can be said that the planar shape of the upper surface 113 of the contact layer 110 is the same as the planar shape of the first gain portion 162 and the second gain portion 172. For example, the current path between the first electrode 112 and the second electrode 114 is determined by the planar shape of the columnar portion 111, and as a result, the planar shapes of the first gain portion 162 and the second gain portion 172 are determined. Although not shown, the side surface of the columnar portion 111 can be inclined.

  As shown in FIG. 3, the third gain portion 164 and the fourth gain portion 174 may have a so-called gain waveguide type cross-sectional shape. That is, the planar shapes of the third gain portion 164 and the fourth gain portion 174 are determined by the opening shape of the insulating layer 116 (the shape of the gain portion where the contact layer 110 and the second electrode 114 are in contact).

  Although not shown, the third gain portion 164 and the fourth gain portion 174 may be so-called refractive index waveguide types. That is, for example, a columnar portion constituted by the contact layer 110 and a part of the second cladding layer 108 is provided, and the planar shape of the third gain portion 164 and the fourth gain portion 174 is the planar shape of the columnar portion. The structure determined by can be taken.

As shown in FIG. 2, the insulating layer 116 is formed on the substrate 102 and on the side of the columnar portion 111. The insulating layer 116 can be in contact with the side surface of the columnar portion 111. The upper surface of the insulating layer 116 is continuous with the upper surface 113 of the contact layer 110, for example. As the insulating layer 116, for example, a SiN layer, a SiO ₂ layer, a SiON layer, an Al ₂ O ₃ layer, a polyimide layer, or the like can be used. The insulating layer 116 in FIG. 2 and the insulating layer 116 in FIG. 3 may be formed of the same material or different materials. The insulating layer 116 may be formed of a single material or a plurality of materials.

  When the above material is used for the insulating layer 116, the current between the first electrode 112 and the second electrode 114 can flow through the columnar portion 111 sandwiched between the insulating layers 116 while avoiding the insulating layer 116. The insulating layer 116 can have a refractive index smaller than that of the active layer 106. In this case, the effective refractive index in the vertical cross section of the first gain portion 162 and the second gain portion 172 where the insulating layer 116 is formed is the first gain where the insulating layer 116 is not formed, that is, the columnar portion 111 is formed. This is smaller than the effective refractive index of the vertical cross section of the portion 162 and the second gain portion 172. Thereby, light can be efficiently confined in the first gain region 160 and the second gain region 170 in the planar direction. Note that although not illustrated, the insulating layer 116 may not be provided. The insulating layer 116 may be interpreted as air.

  The first electrode 112 is formed on the entire lower surface of the substrate 102. The first electrode 112 is in contact with a layer that is in ohmic contact with the first electrode 112 (the substrate 102 in the illustrated example). The first electrode 112 is electrically connected to the first cladding layer 104 via the substrate 102. The first electrode 112 is one electrode for driving the light emitting device 100. As the first electrode 112, for example, a layer in which a Cr layer, an AuGe layer, a Ni layer, and an Au layer are stacked in this order from the substrate 102 side can be used.

  Note that a second contact layer (not shown) is provided between the first cladding layer 104 and the substrate 102, the second contact layer is exposed by dry etching or the like, and the first electrode 112 is placed on the second contact layer. It can also be provided. Thereby, a single-sided electrode structure can be obtained. This form is particularly effective when the substrate 102 is insulative.

  The second electrode 114 is formed in contact with the upper surface 113 of the contact layer 110. Further, the second electrode 114 may be formed on the insulating layer 116. The second electrode 114 is electrically connected to the second cladding layer 108 via the contact layer 110. The second electrode 114 is the other electrode for driving the light emitting device 100. As the second electrode 114, for example, a layer in which a Cr layer, an AuZn layer, and an Au layer are stacked in this order from the contact layer 110 side can be used.

  As described above, the case of the InGaAlP system has been described as an example of the light emitting device 100 according to the present embodiment. However, the light emitting device 100 can use any material system capable of forming a light emission gain region. As the semiconductor material, for example, an AlGaN-based, GaN-based, InGaN-based, GaAs-based, AlGaAs-based, InGaAs-based, InGaAsP-based, or ZnCdSe-based semiconductor material can be used.

  The light emitting device 100 according to the present embodiment can be applied to a light source such as a projector, a display, a lighting device, and a measurement device.

The light emitting device 100 according to the present embodiment has the following features, for example.
According to the light emitting device 100, the first gain region 160 has the first gain portion 162 having the first curvature, and the second gain region 170 has the second gain portion 172 having the second curvature. Have. Therefore, the second end face 182 of the first gain region 160 and the second gain region 170 are not increased without increasing the incident angle β of the light generated in the first gain region 160 and the second gain region 170 with respect to the second surface 132. The distance D between the fourth end surface 186 (the distance D between the exit surfaces) can be increased. Thereby, even when the distance between the lens arrays connected to the light emitting device 100 is large, the radiation pattern of the emitted light can be suppressed from being distorted by being arranged in accordance with the lens array. For example, when the light emitting device is used as a light source of a projector, the ride valve can be illuminated uniformly.

  Furthermore, according to the light emitting device 100, the total length of the gain region does not have to be increased in order to increase the distance D compared to the example using the gain region that is linear from the first surface 130 to the second surface 132. Good. Therefore, it is not necessary to flow a large amount of current, and power consumption can be suppressed. Furthermore, since it is not necessary to increase the overall length of the gain region, the entire apparatus can be reduced in size. Therefore, resources are not wasted and manufacturing costs can be reduced.

  As described above, in the light emitting device 100, the radiation pattern is good, and the distance D can be increased while downsizing. More specifically, for example, in the light emitting device 100, the emission surface interval D is set to 0.262 mm to 1509 mm, the angle β is set to 0 ° to 5 °, and the first gain region 160 and the second gain region 170 are set. The total length can be 1.5 mm or more and 3 mm or less.

  According to the light emitting device 100, the first gain region 160 is inclined with respect to the perpendicular P at the first angle α 1 and is connected to the first surface 130, and the second gain region 170 is connected to the perpendicular P with the second angle α 2. It is possible to connect to the first surface 130 by tilting. The first angle α1 and the second angle α2 may be equal to or greater than the critical angle. Therefore, the first surface 130 can totally reflect light generated in the first gain region 160 and the second gain region 170. Therefore, in the light emitting device 100, light loss on the first surface 130 can be suppressed, and light can be reflected efficiently. Furthermore, since the process of forming the reflective film on the first surface 130 is not necessary, the manufacturing cost and the materials and resources necessary for manufacturing can be reduced.

  According to the light emitting device 100, the first surface 130 may be a cleavage plane formed by cleavage. Therefore, for example, the first surface 130 can be formed with higher accuracy than in the case where the first surface 130 is formed by a photolithography technique and an etching technique, and light scattering at the end face can be reduced. Therefore, in the light emitting device 100, light loss on the first surface 130 can be suppressed, and light can be reflected efficiently.

2. Method for Manufacturing Light-Emitting Device Next, a method for manufacturing a light-emitting device according to the present embodiment will be described with reference to FIGS. 6 to 8 are schematic views for explaining a method for manufacturing a light emitting device. FIG. 7 is a cross-sectional view schematically showing a process of forming the first connection portion 140 and the second connection portion 150 in the light emitting device 100 according to the present embodiment, and corresponds to FIG. FIG. 8 is a cross-sectional view schematically showing a process of forming the first gain portion 162 and the second gain portion 172 in the light emitting device 100 according to the present embodiment, and corresponds to FIG.

  As shown in FIG. 6, on the substrate 102, the first cladding layer 104, the active layer 106, the second cladding layer 108, and the contact layer 110 are epitaxially grown in this order. As a method of epitaxial growth, for example, a MOCVD (Metal Organic Chemical Deposition) method, an MBE (Molecular Beam Epitaxy) method, or the like can be used.

  As shown in FIGS. 7A, 7 </ b> B, and 7 </ b> C, the first connection portion 140 and the second connection portion 150 are formed by patterning a plurality of times according to the number of stages of the connection portions. Here, an example of a connecting portion having a three-step staircase shape is shown. In that case, for example, the process of exposing the position Y2 shown in FIG. 7A, the process of exposing the position Y1 shown in FIG. 7B, and the process of exposing the position Y0 shown in FIG. It is formed by patterning three times. Since the patterning is performed using, for example, a known photolithography technique and etching technique, detailed description is omitted. The order of patterning multiple times is not particularly limited. It can be arbitrarily selected within a range where a staircase shape can be finally formed. That is, for example, the process of exposing the position Y0 shown in FIG. 7C, the process of exposing the position Y1 shown in FIG. 7B, and the process of exposing the position Y2 shown in FIG. You can also. By this step, the first connection portion 140 and the second connection portion 150 can be formed.

  As shown in FIG. 8, subsequently, the first gain portion 162 and the second gain portion 172 are formed by patterning the contact layer 110, the second cladding layer 108, the active layer 106, the first cladding layer 104, and the substrate 102. It is formed. The patterning is performed using, for example, a known photolithography technique and etching technique. Although not shown in detail, the first gain portion 162 and the second gain portion 172 may be formed simultaneously in the process of forming the connection portion, or may be formed in a separate process from the connection portion formation. Good. By this step, the columnar portion 111 can be formed.

As shown in FIGS. 2, 3, and 4, an insulating layer 116 is formed so as to cover the side surface of the columnar portion 111. As the insulating layer 116, as described above, a dielectric insulating layer such as a SiN layer, a SiO ₂ layer, a SiON layer, or an Al ₂ O ₃ layer, an ultraviolet curable resin layer such as a polyimide layer, or a thermosetting resin layer is used. These layers may be stacked to form the insulating layer 116. It should be noted that a predetermined difference is provided between the effective refractive index of the first gain portion 162 and the second gain portion 172 and the effective refractive index of the gain portion avoiding the first gain region 160 and the second gain region 170. To do. As the insulating layer 116, it is desirable to use a dielectric insulating layer having a large refractive index difference from the columnar portion 111. For example, first, the dielectric insulating layer may be formed by a CVD method or a sputtering method, and then a polyimide layer may be formed by a coating method to form the insulating layer 116. Thus, the insulating layer 116 can be formed easily (in a short time) as compared with the case where the dielectric insulating layer is formed thick to form the insulating layer 116. Next, the upper surface 113 of the contact layer 110 is exposed using, for example, a known etching technique. Through the above steps, the insulating layer 116 can be formed.

  Next, the second electrode 114 is formed over the contact layer 110 and the insulating layer 116. Next, the first electrode 112 is formed under the lower surface of the substrate 102. The first electrode 112 and the second electrode 114 are formed by, for example, a known vacuum deposition method. The order of forming the first electrode 112 and the second electrode 114 is not particularly limited.

The light emitting device 100 according to this embodiment can be manufactured through the above steps.
According to the method for manufacturing the light-emitting device 100, it is possible to obtain the light-emitting device 100 that has a good radiation pattern and can increase the interval between a plurality of emission surfaces while reducing the size.

(Embodiment 2)
3. Modification of Light Emitting Device Next, a light emitting device according to the second embodiment will be described with reference to the drawings. Hereinafter, in the light emitting device according to the modified example of the present embodiment, members having the same functions as the constituent members of the light emitting device 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

3.1. Light Emitting Device The present embodiment is different from the first embodiment in that the connecting portion has a slope shape. First, a light emitting device according to a second embodiment will be described with reference to the drawings. FIG. 9 is a schematic plan view illustrating the structure of the light emitting device according to the second embodiment. FIG. 10 is a cross-sectional view of a main part of the light emitting device according to the second embodiment, and is a cross section taken along line IV-IV ′ of FIG. 9, that is, a cross section of the first connection portion 140 and the second connection portion 150. is there. FIG. 11 is an effective refractive index profile in the light emitting device according to the second embodiment, and is an effective refractive index profile of the gain region along the line VV ′ in FIG. 9. 12 to 14 are schematic views for explaining the method for forming the light emitting device according to the second embodiment. FIG. 14 is a schematic cross-sectional view of the gain region along the line IV-IV ′ in FIG. In FIG. 9, the second electrode 114 is not shown for convenience.

  In Embodiment 1, the cross-sectional shape of the 1st connection part 140 and the 2nd connection part 150 of the light-emitting device 100 was step shape. On the other hand, as shown in FIGS. 9 and 10, in the light emitting device 200, the cross-sectional shapes of the first connection portion 140 and the second connection portion 150 are continuous from the position Y0 to the position Y3 as approaching the position X3 from the position X1. Thus, a slope shape is formed so that the height of the columnar portion 111 changes. With this structure, as shown in FIG. 11, the effective refractive indexes of the fifth gain portion 166 and the sixth gain portion 176 are changed from the refractive index n1 to the refractive index n3 as the position X1 approaches the position X3. Can be changed continuously.

  14A shows a state before patterning, FIG. 14B shows a state during the patterning, and FIG. 14C shows a cross-sectional view after the patterning.

  First, as shown in FIG. 12, a hard mask 122 is formed at a position where the first gain portion 162, the second gain portion 172, the fifth gain portion 166, and the sixth gain portion 176 are formed.

  Thereafter, as shown in FIGS. 13 and 14A, a resist 118 having a slope shape is formed in order to form the first connection portion 140 and the second connection portion 150. The resist 118 can be formed in a slope shape, for example, by forming a resist pattern by a known photolithography technique and then performing a registry flow process by means such as heating the substrate. Here, an example in which the hard mask 122 is formed also in the gain region in which the third gain portion 164 and the fourth gain portion 174 are formed is shown, but the mask in the gain region may be formed of a resist instead of the hard mask. Good.

  Next, etching is performed using the resist 118 formed by the above method as a mask. Since the resist 118 has a slope shape, after etching, this shape becomes an epitaxial crystal substrate (here, the substrate 102, the first cladding layer 104, the active layer 106, the second cladding layer 108, and the contact). A multilayer substrate composed of the layer 110). At this time, it is desirable to use an etching condition in which the etching rate of the resist 118 and the etching rate of the epitaxial crystal substrate are approximately equal and have high perpendicularity. Thereby, the shape of the resist 118 can be more accurately transferred to the epitaxial crystal substrate as shown in FIG. 14C through the state of FIG.

  Through the above steps, the first connection portion 140 and the second connection portion 150 whose cross-sectional shape is a slope shape can be formed.

  According to the light emitting device 200, as with the light emitting device 100, an interface between the first gain portion 162 and the third gain portion 164 that is generated when light is guided from the first gain portion 162 to the third gain portion 164. Can reduce reflection loss. Similarly, by providing the second connection portion 150, the light is guided from the second gain portion 172 to the fourth gain portion 174 at the interface between the second gain portion 172 and the fourth gain portion 174. Reflection loss can be reduced. As a result, light can be efficiently emitted from the second end surface 182 and the fourth end surface 186.

(Embodiment 3)
3.2. Modified example of light emitting device (incident on reflection end face through straight waveguide)
First, a light-emitting device according to Embodiment 3 will be described with reference to the drawings. FIG. 15 is a schematic plan view showing the structure of the light emitting device according to the third embodiment. In FIG. 15, the second electrode 114 is not shown for convenience. Hereinafter, in the light emitting device according to the present embodiment, members having the same functions as those of the constituent members of the light emitting device 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the example of the light emitting device 100, the first gain portion 162 and the second gain portion 172 having curvature are connected to the first surface 130. On the other hand, in the light emitting device 300, as shown in FIG. 15, linear seventh gain portion 168 and eighth gain portion 178 are connected to the first surface 130.

  That is, the first gain region 160 has a seventh gain portion 168 that is linearly provided from the first surface 130 to the first gain portion 162. That is, the seventh gain portion 168 constitutes the first end face 180 of the first gain region 160. The seventh gain portion 168 is inclined at a first angle α1 on one side (for example, the third surface 134 side) with respect to the perpendicular P. The seventh gain portion 168 is smoothly connected to the arc-shaped first gain portion 162. For example, the seventh gain portion 168 is provided to be parallel to a tangent at a point on the boundary between the first gain portion 162 and the seventh gain portion 168.

  The second gain region 170 has an eighth gain portion 178 provided linearly from the first surface 130 to the second gain portion 172. That is, the eighth gain portion 178 constitutes the third end face 184 of the second gain region 170. The eighth gain portion 178 is inclined with respect to the perpendicular P to the other side (for example, the fourth surface 136 side) at a second angle α2. The eighth gain portion 178 is smoothly connected to the arc-shaped second gain portion 172. For example, at the point on the boundary between the second gain portion 172 and the eighth gain portion 178, the tangent line of the second gain portion 172 and the tangent line of the eighth gain portion 178 are provided in parallel. The seventh gain portion 168 and the eighth gain portion 178 may be arranged symmetrically with respect to the perpendicular line P.

  According to the light emitting device 300, as described above, the linear seventh gain portion 168 and eighth gain portion 178 constitute the first end surface 180 and the third end surface 184 provided on the first surface 130. . Therefore, in the light emitting device 300, light generated in the first gain region 160 and reflected on the first surface 130 is incident on the second gain region 170 more reliably than in the example of the light emitting device 100. Light generated at 170 and reflected at the first surface 130 can be incident on the first gain region 160.

(Embodiment 4)
3.3. Modification of Light Emitting Device Next, a light emitting device according to a fourth embodiment will be described with reference to the drawings. FIG. 16 is a schematic plan view illustrating the structure of the light emitting device according to the fourth embodiment. In FIG. 16, the second electrode 114 is not shown for convenience. Hereinafter, in the light emitting device according to the present embodiment, members having the same functions as those of the constituent members of the light emitting device 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the example of the light emitting device 100, the first gain region 160 and the second gain region 170 are provided one by one. On the other hand, in the light emitting device 400, as shown in FIG. 16, a plurality of first gain regions 160 and second gain regions 170 are provided.

  That is, the first gain region 160 and the second gain region 170 can constitute a gain region pair 450, and the light emitting device 400 is provided with a plurality of gain region pairs 450. In the illustrated example, three gain region pairs 450 are provided, but the number thereof is not particularly limited.

  The plurality of gain region pairs 450 are arranged along a direction orthogonal to the direction in which the perpendicular line P extends. More specifically, in the adjacent gain region pair 450, the distance between the fourth end surface 186 of one gain region pair 450 and the second end surface 182 of the other gain region pair 450 is D (injection). Are arranged so that there is a gap between the faces). Thereby, the emitted lights 20 and 22 can be easily incident on a lens array which will be described later.

  According to the light emitting device 400, higher output can be achieved compared to the example of the light emitting device 100.

(Embodiment 5)
4). Projector Next, a projector according to a fifth embodiment will be described with reference to the drawings. FIG. 17 is a schematic diagram illustrating a structure of the projector according to the fifth embodiment. FIG. 18 is a main part schematic diagram illustrating a configuration of the projector according to the fifth embodiment. In FIG. 17, for convenience, the casing constituting the projector is omitted and the light source is simplified. In FIG. 18, for convenience, the light source, the lens array, and the liquid crystal light valve are illustrated, and the light source is illustrated in a simplified manner.

  As shown in FIG. 17, the projector 700 includes a red light source 600R that emits red light, green light, and blue light, a green light source 600G, and a blue light source 600B. The light sources 600R, 600G, and 600B include any one of the light emitting device 100, the light emitting device 200, the light emitting device 300, and the light emitting device 400 according to the present embodiment. In the following example, light sources 600R, 600G, and 600B having the light emitting device 400 as the light emitting device according to the present invention will be described.

  FIG. 19 is a schematic diagram illustrating a light source of the projector according to the fifth embodiment. FIG. 20 is a schematic side sectional view showing a light source of the projector according to the fifth embodiment, and is a sectional view taken along line XIII-XIII in FIG.

  As shown in FIGS. 19 and 20, the light source 600 includes a light emitting device 400, a base 610, and a submount 620.

  The two light emitting devices 400 and the submount 620 can form the structure 630. A plurality of structures 630 are provided on the base 610, and as shown in FIG. 19, a direction (Y direction) orthogonal to the arrangement direction (X direction) of the second end surface 182 and the fourth end surface 186 that are the emission surfaces of the light emitting device 400 ). The structures 630 can be arranged so that the interval between the exit surfaces in the X direction is the same as the interval between the exit surfaces in the Y direction. Thereby, the light emitted from the light emitting device 400 can be easily incident on the lens arrays 702 of the lens array 702R, the lens array 702G, and the lens array 702B.

  The two light emitting devices 400 constituting the structure 630 are arranged with the submount 620 interposed therebetween. The two light emitting devices 400 are arranged so that the second electrodes 114 face each other through the submount 620. For example, wiring is formed on the surface of the submount 620 that contacts the second electrode 114. Thereby, a voltage can be individually supplied to each of the plurality of second electrodes 114. Examples of the material of the submount 620 include aluminum nitride and aluminum oxide.

  The base 610 supports the structure 630. In the example illustrated in FIG. 20, the base 610 is connected to the first electrodes 112 of the plurality of light emitting devices 400. Accordingly, the base 610 can function as a common electrode for the plurality of first electrodes 112. Examples of the material of the base 610 include copper and aluminum. Although not shown, the base 610 may be connected to a heat sink via a Peltier element.

  Note that the form of the structure 630 is not limited to the example illustrated in FIGS. 19 and 20. 21 and 22 are schematic cross-sectional side views showing modifications of the light source of the projector according to the fifth embodiment. For example, as illustrated in FIG. 21, the two light emitting devices 400 included in the structure 630 include a first electrode 112 of one light emitting device 400 and a second electrode of the other light emitting device 400 via a submount 620. 114 may be arranged so as to be opposed to each other. In addition, as illustrated in FIG. 22, the first electrodes 112 of the two light emitting devices 400 may be arranged to be a common electrode.

  As shown in FIG. 17, the projector 700 further includes lens arrays 702R, 702G, and 702B, transmissive liquid crystal light valves 704R, 704G, and 704B as light modulators, a projection lens 708 as a projector, and a display. A screen 710 as a surface.

  Light emitted from the light sources 600R, 600G, and 600B is incident on the lens arrays 702R, 702G, and 702B. As shown in FIG. 18, the lens array 702 can have a flat surface 701 on the light source 600 side on which the emitted lights 20 and 22 emitted from the second end surface 182 and the fourth end surface 186 are incident. A plurality of flat surfaces 701 are provided corresponding to the plurality of second end surfaces 182 and fourth end surfaces 186, and are arranged at equal intervals. The flat surface 701 makes it possible to make the optical axes of the emitted lights 20 and 22 orthogonal to the irradiation surface 705 of the liquid crystal light valve 704.

  The lens array 702 can have a convex curved surface 703 on the liquid crystal light valve 704 side. A plurality of convex curved surfaces 703 are provided corresponding to the plurality of flat surfaces 701 and are arranged at equal intervals. The emitted lights 20 and 22 whose optical axes are converted on the flat surface 701 can be superposed (partially superposed) by being condensed by the convex curved surface 703 or by reducing the diffusion angle. Thereby, the liquid crystal light valve 704 can be irradiated with good uniformity.

  As described above, the lens array 702 can collect the emitted lights 20 and 22 by controlling the optical axes of the emitted lights 20 and 22 emitted from the light source 600.

  As shown in FIG. 17, the light condensed by the lens arrays 702R, 702G, and 702B is incident on the liquid crystal light valves 704R, 704G, and 704B. Each of the liquid crystal light valves 704R, 704G, and 704B modulates incident light according to image information. The projection lens 708 enlarges and projects the image formed by the liquid crystal light valves 704R, 704G, and 704B onto the screen (display surface) 710.

  In addition, the projector 700 can include a cross dichroic prism 706 as a color light combining unit that combines the light emitted from the liquid crystal light valves 704R, 704G, and 704B and guides the light to the projection lens 708.

  The three color lights modulated by the liquid crystal light valves 704R, 704G, and 704B are incident on the cross dichroic prism 706. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the screen 710 by the projection lens 708 which is a projection optical system, and an enlarged image is displayed.

  The projector 700 has the light emitting device 400 that has a good radiation pattern, can be designed to be small, and can design the interval between the plurality of emission surfaces to a desired value. Therefore, in the projector 700, the alignment of the lens array 702 is easy, and the liquid crystal light valve 704 can be irradiated with good uniformity.

  In the above example, a transmissive liquid crystal light valve is used as the light modulation device. However, a light valve other than liquid crystal may be used, or a reflective light valve may be used. Examples of such a light valve include a reflection type liquid crystal light valve and a digital micromirror device (Digital Micromirror Device). Further, the configuration of the projection optical system is appropriately changed depending on the type of light valve used.

  In addition, the light source 600 scans light on the screen with the light from the light source 600 to display a desired size image on the display surface. It can also be applied to a light source device of a projector.

  A light emitting device 400 is mounted on a light source 600 included in the projector 700. Since the light emitting device 400 efficiently emits the emitted light 20 and the emitted light 22, the projector 700 can emit light efficiently.

  The above-described embodiments and modifications are merely examples, and the present invention is not limited to these. For example, it is possible to appropriately combine each embodiment and each modification.

  Although the embodiments of the present invention have been described in detail as described above, those skilled in the art can easily understand that many modifications can be made without departing from the novel matters and effects of the present invention. Therefore, all such modifications are included in the scope of the present invention.

  DESCRIPTION OF SYMBOLS 104 ... 1st clad layer as 1st layer, 106 ... Active layer as 3rd layer, 108 ... 2nd clad layer as 2nd layer, 110 ... Contact layer as 4th layer, 112 ... 1st electrode, 114: second electrode, 116: insulating layer, 120: laminate, 130: first surface, 132: second surface, 160: first gain region, 162: first gain portion, 164: third gain portion, 166 ... 5th gain portion, 168 ... 7th gain portion, 170 ... 2nd gain region, 172 ... 2nd gain portion, 174 ... 4th gain portion, 176 ... 6th gain portion, 178 ... 8th gain portion, 600 ... Light source as light emitting device, 600B ... Blue light source as light emitting device, 600G ... Green light source as light emitting device, 600R ... Red light source as light emitting device, 700 ... Projector, 702, 702B, 702G, 702R ... My Lens array as Rorenzu, 704,704B, 704G, 704R ... liquid crystal light valve as an optical modulator, 708 ... projection lens as a projection device, [alpha] 1 ... first angle, [alpha] 2 ... second angle.

Claims (7)

A first layer; a second layer; a third layer sandwiched between the first layer and the second layer; and a fourth layer formed on the opposite side of the second layer to the third layer side. A laminate,
A first electrode electrically connected to the first layer;
A second electrode electrically connected to the second layer and in contact with the fourth layer;
Including
The third layer has a first gain region and a second gain region in which light is generated and light is guided, and when viewed from the stacking direction of the stacked body, the first gain region and the second gain region The shape of the gain region is the same shape as the contact surface between the fourth layer and the second electrode,
The first layer and the second layer are layers that suppress leakage of light generated in the first gain region and the second gain region,
The fourth layer is a layer in ohmic contact with the second electrode,
The third layer has a first surface and a second surface facing each other, and in the wavelength band of light generated in the first gain region and the second gain region, the reflectance of the first surface is The reflectance of the second surface is higher, and the first gain region and the second gain region are provided from the first surface to the second surface,
The first gain region is inclined to one side with respect to the perpendicular to the first surface when viewed from the stacking direction of the stacked body, and is connected to the first surface,
The second gain region is connected to the first surface inclined to the other side with respect to the perpendicular when viewed from the stacking direction of the stacked body,
The first gain region and the second gain region are connected to the second surface inclined in the same inclination as seen from the stacking direction of the stacked body,
The end surface on the first surface side of the first gain region and the end surface on the first surface side of the second gain region overlap on the first surface,
The first gain region includes a first gain portion having a first curvature, a linear third gain portion, the first gain portion, and the third gain portion as viewed from the stacking direction of the stacked body. And a fifth gain portion connected to
The second gain region includes a second gain portion having a second curvature, a linear fourth gain portion, the second gain portion, and the fourth gain portion as viewed from the stacking direction of the stacked body. A sixth gain portion connected to
The first gain region and the second gain region are sandwiched between insulating layers when viewed from the stacking direction of the stacked body, and effective refraction of the insulating layer in contact with the first gain portion and the second gain portion. When the refractive index is the first refractive index and the effective refractive index in contact with the third gain portion and the fourth gain portion is the second refractive index, the refractive index in contact with the fifth gain portion and the sixth gain portion is Light emission characterized by switching stepwise from the first refractive index to the second refractive index as the first gain portion and the third gain portion approach the second gain portion and the fourth gain portion. apparatus. A first layer; a second layer; a third layer sandwiched between the first layer and the second layer; and a fourth layer formed on the opposite side of the second layer to the third layer side. A laminate,
A first electrode electrically connected to the first layer;
A second electrode electrically connected to the second layer and in contact with the fourth layer;
Including
The third layer has a first gain region and a second gain region in which light is generated and light is guided, and when viewed from the stacking direction of the stacked body, the first gain region and the second gain region The shape of the gain region is the same shape as the contact surface between the fourth layer and the second electrode,
The first layer and the second layer are layers that suppress leakage of light generated in the first gain region and the second gain region,
The fourth layer is a layer in ohmic contact with the second electrode,
The third layer has a first surface and a second surface facing each other, and in the wavelength band of light generated in the first gain region and the second gain region, the reflectance of the first surface is The reflectance of the second surface is higher, and the first gain region and the second gain region are provided from the first surface to the second surface,
The first gain region is inclined to one side with respect to the perpendicular to the first surface when viewed from the stacking direction of the stacked body, and is connected to the first surface,
The second gain region is connected to the first surface inclined to the other side with respect to the perpendicular when viewed from the stacking direction of the stacked body,
The first gain region and the second gain region are connected to the second surface inclined in the same inclination as seen from the stacking direction of the stacked body,
The end surface on the first surface side of the first gain region and the end surface on the first surface side of the second gain region overlap on the first surface,
The first gain region includes a first gain portion having a first curvature, a linear third gain portion, the first gain portion, and the third gain portion as viewed from the stacking direction of the stacked body. And a fifth gain portion connected to
The second gain region includes a second gain portion having a second curvature, a linear fourth gain portion, the second gain portion, and the fourth gain portion as viewed from the stacking direction of the stacked body. A sixth gain portion connected to
Have
The first gain region and the second gain region are sandwiched between insulating layers when viewed from the stacking direction of the stacked body, and effective refraction of the insulating layer in contact with the first gain portion and the second gain portion. When the refractive index is the first refractive index and the effective refractive index in contact with the third gain portion and the fourth gain portion is the second refractive index, the refractive index in contact with the fifth gain portion and the sixth gain portion is Light emission characterized by switching from the first refractive index to the second refractive index as the first gain portion and the third gain portion approach the second gain portion and the fourth gain portion. apparatus. The light emitting device according to claim 1 or 2,
The first gain region is connected to the first surface inclined at a first angle with respect to the normal;
The second gain region is connected to the first surface inclined at a second angle with respect to the normal;
The light emitting device, wherein the first angle and the second angle are equal to or greater than a critical angle. In the light-emitting device of any one of Claims 1-3,
The first gain region is
A seventh gain portion provided linearly from the first surface to the first gain portion;
The second gain region is
A light emitting device comprising: an eighth gain portion provided linearly from the first surface to the second gain portion. In the light-emitting device of any one of Claims 1-4,
The light emitting device according to claim 1, wherein the first gain portion and the second gain portion have an arc shape when viewed from a stacking direction of the stacked body. In the light-emitting device of any one of Claims 1-5,
The light emitting device, wherein the first surface is a cleavage surface. The light emitting device according to any one of claims 1 to 6,
A microlens for collecting the light emitted from the light emitting device;
A light modulation device that modulates light collected by the microlens according to image information;
A projection device for projecting an image formed by the light modulation device;
Including a projector.