JP5344173B2 - Light emitting device and projector - Google Patents

Description

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

  In recent years, laser diodes having high luminance and excellent color reproducibility are expected as light emitting elements used in light emitting devices for light sources of display devices such as projectors and displays. Here, the laser light emitted from the laser diode is coherent light, but in the light emitting device for the light source, it is desirable that the light is incoherent light in consideration of safety. For example, Patent Document 1 proposes a light source device (light emitting device) using a phosphor that absorbs laser light emitted from a laser diode and emits incoherent light as spontaneous emission light. However, in the light emitting device using the phosphor, the light use efficiency of the light emitted from the light emitting element may be lowered.

JP 2003-295319 A

  One of the objects according to some embodiments of the present invention is to provide a light-emitting device that has high light utilization efficiency and can obtain incoherent light.

The light emitting device according to the present invention is
A superluminescent diode, a light emitting element having a first emission surface and a second emission surface that emit light traveling in opposite directions;
A plane mirror that reflects light emitted from the first emission surface;
A first parabolic mirror that converts light reflected by the plane mirror into parallel light;
A second parabolic mirror that converts light emitted from the second emission surface into parallel light;
Including
The first emission surface is disposed at a position symmetrical to the focal point of the first paraboloidal mirror with respect to the plane mirror.
The second exit surface is disposed at a focal point of the second parabolic mirror;
The optical axis of the first parabolic mirror and the optical axis of the second parabolic mirror are parallel.

  According to such a light emitting device, the light emitting element can be a super luminescent diode and can have the plane mirror. Accordingly, the light emitting element can directly emit incoherent light without using another member, and the light emitted from the first emission surface and the light emitted from the second emission surface are used. Therefore, it is possible to have high light utilization efficiency.

In the light emitting device according to the present invention,
And a frame for fixing the light emitting element, the reflecting mirror, the first parabolic mirror, and the second parabolic mirror,
The frame may be formed of a material that is transparent to the wavelength of light emitted from the first emission surface and the second emission surface.

  According to such a light emitting device, it is possible to reduce light absorption loss in the frame.

In the light emitting device according to the present invention,
The first parabolic mirror and the second parabolic mirror may be integrally formed.

  According to such a light emitting device, the manufacturing process of the first parabolic mirror and the second parabolic mirror can be simplified.

The projector according to the present invention is
A light emitting device according to the present invention;
A light modulation device that modulates light emitted from the light emitting device according to image information;
A projection device for projecting an image formed by the light modulation device;
including.

  According to such a projector, since the light emitting device is included, a light emitting device that has high light utilization efficiency and can obtain incoherent light can be used as a light source.

The figure which shows typically the light-emitting device which concerns on this embodiment. FIG. 3 is a cross-sectional view schematically showing the light emitting device according to the embodiment. FIG. 3 is a cross-sectional view schematically showing the light emitting device according to the embodiment. The figure for demonstrating the positional relationship of a light emitting element and a mirror. Sectional drawing which shows typically the manufacturing process of the light-emitting device which concerns on this embodiment. Sectional drawing which shows typically the manufacturing process of the light-emitting device which concerns on this embodiment. Sectional drawing which shows typically the modification of the light-emitting device which concerns on this embodiment. 1 is a diagram schematically showing a projector according to an embodiment.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

1. First, the light emitting device 1000 according to the present embodiment will be described with reference to the drawings. FIG. 1 is a diagram schematically showing a light emitting device 1000. 2 is a cross-sectional view taken along line II-II shown in FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. In FIG. 1, the second electrode 114 is not shown for convenience. In FIG. 2, the light emitting element 100 is simplified for convenience.

  1 to 3, the light emitting device 1000 includes a light emitting element 100, a first optical element 200 having a plane mirror 202, a second optical element 210 having a first parabolic mirror 212, and a second optical element. A third optical element 220 having a parabolic mirror 222. The light emitting device 1000 can further include a frame 300.

  The light emitting element 100 is formed on the frame 300 as shown in FIGS. As shown in FIG. 3, the light emitting device 100 includes a substrate 102, a first cladding layer 104, an active layer 106, a second cladding layer 108, a contact layer 110, a first electrode 112, and a second electrode 114. And an insulating part 116. Note that here, a case where the light-emitting element 100 is an InGaAlP-based (red) light-emitting element will be described.

  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. The first cladding layer 104 is made of, for example, a first conductivity type semiconductor. As the first cladding layer 104, for example, an n-type InGaAlP layer can be used. 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, a first conductivity type (n-type) GaAs layer or InGaP layer having better crystallinity than the substrate 102 (for example, having a lower defect density) can be used.

The active layer 106 is formed on the first cladding layer 104. 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. A partial region of the active layer 106 constitutes a gain region 120 that becomes a current path of the active layer 106. The gain region 120 can generate light, and this light can receive gain within the gain region 120. The shape of the active layer 106 is, for example, a rectangular parallelepiped (including a cube). The first clad layer 104, the second clad 108, and the active layer 106 constitute a laminated structure 101. As shown in FIG. 1, the active layer 106 has a first surface 105 and a second surface 107. The first surface 105 and the second surface 107 of the active layer 106 are surfaces that are not in contact with the first cladding layer 104 or the second cladding layer 108 among the surfaces of the active layer 106, and are exposed in the laminated structure 101. It is a surface. It can be said that the first surface 105 and the second surface 107 are side surfaces of the active layer 106. The first surface 105 and the second surface 107 face each other, and are parallel, for example. The first surface 105 and the second surface 107 may be covered with an antireflection film (not shown). Thereby, a low reflectance can be obtained. For example, an Al ₂ O ₃ single layer can be used as the antireflection film. As the antireflection film, but it is not limited to the example described above, for example, for example, SiO ₂ layer, SiN layer, SiON layer, _Ta 2 _{O 5} layer, TiO ₂ layer, and TiN layer, these multilayer A film or the like can be used.

  As shown in FIG. 1, the gain region 120 is provided from the first end surface 122 on the first surface 105 side to the second end surface 124 on the second surface 107 side. The gain region 120 is provided in a direction inclined with respect to the normal line P from the first surface 105 to the second surface 107 in plan view from the stacking direction of the active layer 106 (viewed from the thickness direction of the active layer 106). It has been. That is, as shown in FIG. 1, the line connecting the center of the first end face 122 and the center of the second end face 124 in plan view from the stacking direction of the active layer 106 (viewed from the thickness direction of the active layer 106) is The first surface 105 is inclined with respect to the normal P. Thereby, the laser oscillation of the light generated in the gain region 120 can be suppressed or prevented. In other words, the light emitting element 100 can be a super luminescent diode (SLD). Unlike a laser diode, an SLD can prevent laser oscillation by suppressing the formation of a resonator due to end face reflection. Thereby, incoherent light can be obtained.

  The second cladding layer 108 is formed on the active layer 106. The second cladding layer 108 is made of, for example, a second conductivity type (eg, p-type) semiconductor. As the second cladding layer 108, for example, a p-type InGaAlP layer can be used.

  For example, the n-type first cladding layer 104, the active layer 106 not doped with impurities, and the p-type second cladding layer 108 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 amplifying light. The first cladding layer 104 and the second cladding layer 108 have a function of confining injected carriers (electrons and holes) and light with the active layer 106 interposed therebetween.

  The contact layer 110 can be formed on the second cladding layer 108. As the contact layer 110, a layer in ohmic contact with the second electrode 114 can be used. The contact layer 110 is made of, for example, a second conductivity type semiconductor. As the contact layer 110, for example, a p-type GaAs layer can be used.

  The contact layer 110 and a part of the second cladding layer 108 can form a columnar portion 111. The planar shape of the columnar portion 111 is the same as the planar shape of the gain region 120, as shown in FIG. That is, for example, the current path between the electrodes 112 and 114 is determined by the planar shape of the columnar portion 111, and as a result, the planar shape of the gain region 120 is determined. Although not shown, the columnar portion 111 can be composed of, for example, the contact layer 110, a part of the second cladding layer 108, a part of the active layer 106, and a part of the first cladding layer 104. Although not shown, the side surface of the columnar part 111 may be inclined.

As shown in FIG. 3, the insulating part 116 can be provided on the second cladding layer 108 and on the side of the columnar part 111. The insulating part 116 is in contact with the side surface of the columnar part 111. The upper surface of the insulating part 116 can be continuous with, for example, the upper surface of the contact layer 110. As the insulating part 116, for example, a SiN layer, a SiO ₂ layer, a polyimide layer, or the like can be used. When these materials are used as the insulating portion 116, the current between the electrodes 112 and 114 can flow through the columnar portion 111 sandwiched between the insulating portions 116, avoiding the insulating portion 116. The insulating part 116 may have a refractive index smaller than that of the active layer 106. In this case, the effective refractive index of the vertical cross section of the portion where the insulating portion 116 is formed is smaller than the effective refractive index of the vertical cross section of the portion where the insulating portion 116 is not formed, that is, the portion where the columnar portion 111 is formed. Thereby, light can be efficiently confined in the gain region 120 in the planar direction. Further, the insulating portion 116 can be omitted. The insulating portion 116 may be interpreted as air. In that case, the columnar portion 111 does not include the active layer 106 and the first cladding layer 104, or the second electrode 114 does not directly contact the active layer 106 and the first cladding layer 104. There is a need.

  The first electrode 112 is formed on the entire lower surface of the substrate 102. The first electrode 112 can be in contact with a layer that is in ohmic contact with the first electrode 112 (the substrate 102 in the illustrated example). Thereby, the contact resistance of the 1st electrode 112 can be reduced. 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 element 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 can be formed on the entire surface of the contact layer 110 (columnar portion 111) and the insulating portion 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 element 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. The contact surface between the second electrode 114 and the contact layer 110 has a planar shape similar to that of the gain region 120 as shown in FIG.

  In the light emitting element 100, when a forward bias voltage of a pin diode is applied between the first electrode 112 and the second electrode 114, recombination of electrons and holes occurs in the gain region 120 of the active layer 106. This recombination causes light emission. Starting from this generated light, stimulated emission occurs in a chain, light travels in the gain region 120, the light intensity is amplified during that time, and is emitted from the first end face 122 as the first emitted light 10, and the second The light can be emitted from the end surface 124 as the second emitted light 12. That is, the first end surface 122 and the second end surface 124 can be the emission surface (first emission surface, second emission surface) of the light emitting element 100. The first outgoing light 10 emitted from the first outgoing surface 122 and the second outgoing light 12 emitted from the second outgoing surface 124 are, for example, in the gain region 120 with respect to the perpendicular P of the first surface 105 due to light refraction. The light can be emitted in a direction further inclined than the inclination. The magnitude of the inclination of the traveling direction of the first emitted light 10 with respect to the perpendicular P is the same as the magnitude of the inclination of the traveling direction of the second emitted light 12 with respect to the perpendicular P. The traveling direction of the first emitted light 10 and the traveling direction of the second emitted light 12 are, for example, opposite directions.

  The first optical element 200 has a plane mirror 202 as shown in FIG. The surface of the first optical element 200 on which the first outgoing light 10 is incident can be the plane mirror 202. The plane mirror 202 is a mirror composed of a plane. The plane mirror 202 can reflect the first outgoing light 10 and make it incident on the first parabolic mirror 212. Examples of the material of the first optical element 200 include Al, Ag, Au, and the like. For example, only the flat mirror 202 portion of the first optical element 200 may be made of the materials listed above.

The second optical element 210 has a first parabolic mirror 212. The surface of the second optical element 210 on which the light 10 d reflected by the plane mirror 202 is incident can be the first parabolic mirror 212. The first parabolic mirror 212 is a mirror constituted by a rotating paraboloid (a surface obtained by rotating a parabola around an axis (optical axis Q ₁ in the illustrated example)). Examples of the material of the second optical element 210 include Al, Ag, Au, and the like. For example, only the portion of the first parabolic mirror 212 of the second optical element 210 may be made of the materials listed above. The first parabolic mirror 212 reflects the light 10d reflected by the plane mirror 202, and the first reflected light 20 is, for example, an optical system in the subsequent stage (for example, uniformizing optical systems 1002R, 1002G, 1002B (FIG. 8))).

The third optical element 220 has a second parabolic mirror 222. The surface of the third optical element 220 on which the second emitted light 12 is incident can be the second parabolic mirror 222. The second parabolic mirror 222 is a mirror formed of a rotating paraboloid (a surface obtained by rotating a parabola around an axis (the optical axis Q ₂ in the illustrated example)). Examples of the material of the third optical element 220 include Al, Ag, Au, and the like. For example, only the second parabolic mirror 222 portion of the third optical element 220 may be made of the materials listed above. The second parabolic mirror 222 can reflect the second outgoing light 12 and make it incident on the subsequent optical system as the second reflected light 22, for example. For example, the second optical element 210 and the third optical element 220 can be integrally formed. That is, the first parabolic mirror 212 and the second parabolic mirror 222 can be integrally formed. For example, the first parabolic mirror 212 and the second parabolic mirror 222 can be integrally formed in parallel. Since the first parabolic mirror 212 and the second parabolic mirror 222 are integrally formed, the manufacturing process of the parabolic mirrors 212 and 222 can be simplified.

  As shown in FIG. 1, the first emission surface (first end surface) 122 of the light emitting element 100 is disposed at a position C that is symmetrical with the focal point A of the first parabolic mirror 212 with respect to the plane mirror 202. Yes. In other words, the first exit surface 122 is on the perpendicular of the plane mirror 202 passing through the focal point A, and the distance to the intersection where the perpendicular intersects the plane mirror 202 is equal to the distance between the intersection and the focal point A. C. Thereby, the first parabolic mirror 212 can convert the light 10d reflected by the plane mirror 202 into parallel light. For example, as shown in FIG. 1, the first emission surface (first end surface) 122 may be arranged so that the center is located at the position C. The first emission surface (first end surface) 122 may be arranged so that at least a part thereof is located at the position C.

The second emission surface (second end surface) 124 of the light emitting element 100 is disposed at the focal point B of the second parabolic mirror 222. Thereby, the second parabolic mirror 222 can convert the second outgoing light 12 into parallel light. For example, as shown in FIG. 1, the second emission surface (second end surface) 124 may be disposed so that the center is located at the focal point B. The second emission surface (second end surface) 124 may be arranged so that at least a part thereof is located at the focal point B. The optical axis to Q ₁ first parabolic mirror 212, the optical axis Q ₂ of the second parabolic mirror 222 may be parallel. Accordingly, the traveling direction of the first reflected light 20 and the traveling direction of the second reflected light 22 can be the same direction. Here, the optical axis Q ₁ of the first parabolic mirror 212 can refer to a line connecting the focal point A of the first parabolic mirror 212 and the center O ₁ of the first parabolic mirror 212. . The optical axis Q ₂ of the second parabolic mirror 222 can be a line connecting the focal point B of the second parabolic mirror 222 and the center O ₂ of the second parabolic mirror 222.

FIG. 4 is a diagram for explaining the positional relationship between the light emitting element 100 and the mirrors 202, 212, and 222 in the light emitting device 1000. Here, the light 10d reflected by the plane mirror 202 is formed on the surface F when the radiation profile defined by the radiation angle 2θ propagates to the surface F. center) of the radiation profile and L ₁ is, the radiation profile second outgoing light 12 is defined at the center (emission angle 2θ region of irradiating the surface F is when propagated to the surface F, is formed on the surface F If the center) of the radiation profile was _{L 2,} the distance _L 1 _{L 2} between _{L 1} and _{L 2} is expressed as follows.

L ₁ L ₂ = L × (sin θ _d −cos θ _d × tan θ _w )
Where L is the distance between the first surface 105 and the second surface 107 of the active layer 106, θ _d is the angle formed by the perpendicular P and the traveling direction of the emitted light 10, 12, and θ _w Is the inclination angle of the gain region 120 with respect to the perpendicular P.

Further, assuming that a position symmetric with respect to the center C of the first exit surface 122 with respect to the plane mirror 202 is a point A, a distance L ₁ A between L ₁ and the point A is expressed as follows.

L ₁ A = L × (cos θ _d + sin θ _d × tan θ _w ) + a + 2 × M
Where a is the distance between L ₂ and the center B of the second exit surface 124, and M is the distance between the center C of the first exit surface 122 and the plane mirror 202.

Further, the end of the irradiation region on the surface F of the light 10d reflected by the plane mirror 202 (the end of the radiation profile formed on the surface F when the radiation profile defined by the radiation angle 2θ _x propagates to the surface F) is obtained. When D, the distance L _{1 D} between L ₁ and D is expressed as follows.

L ₁ D = L ₁ A × tan θ
However, (theta) is an angle of 1/2 of the radiation angle of the emitted light 10 and 12. FIG. Here, the radiation angle of the first outgoing light 10 and the radiation angle of the second outgoing light 12 are equal.

Further, when the end of the irradiation region on the surface F of the second outgoing light 12 (the end of the radiation profile formed on the surface F when the radiation profile defined by the radiation angle 2θ _x propagates to the surface F) is E, the distance _{L 2} E between L ₂ and E is represented as follows.

L ₂ E = a × tan θ
At this time, if L ₁ L ₂ > L ₁ D + L ₂ E, the first outgoing light 10 and the second outgoing light 12 approximately do not overlap on the surface F. Therefore, the point A and the focal point, and the first parabolic mirror 212 centered on the L ₁ side F, the center B of the second output surface 124 and a focal point, a second discharge around the L ₂ side F The object mirror 222 can be integrally formed in parallel.

  The frame 300 includes a light emitting element 100, a first optical element 200 having a plane mirror 202, a second optical element 210 having a first paraboloid mirror 212, and a third optical element 220 having a second paraboloid mirror 222. Can be fixed. The frame 300 can be made of a material that is transmissive to the wavelengths of the outgoing lights 10 and 12. Thereby, at least a part of the emitted lights 10 and 12 can pass through the frame 300. Further, at least a part of the reflected lights 20 and 22 can pass through the frame 300. The frame 300 can be made of, for example, quartz, glass, quartz, plastic, or the like. These can be appropriately selected according to the wavelengths of the outgoing lights 10 and 12. Thereby, the absorption loss of light can be reduced. Although not shown, the frame 300 may be formed with electrodes that electrically connect the light emitting element 100 and an external circuit (not shown).

  As an example of the light-emitting device 1000, the case where the light-emitting element 100 is an InGaAlP system has been described, but the light-emitting element 100 can use any material system capable of forming a light-emitting gain region. As the semiconductor material, for example, an AlGaN-based, InGaN-based, GaAs-based, InGaAs-based, GaInNAs-based, or ZnCdSe-based semiconductor material can be used.

  The light emitting device 1000 according to the present embodiment can be applied to a light source such as a projector, a display, a lighting device, and a measuring device.

  The light emitting device 1000 according to the present embodiment has, for example, the following characteristics.

  In the light emitting device 1000, the light emitting element 100 may be a super luminescent diode. Thereby, according to the light-emitting device 1000, the light-emitting element 100 can directly emit incoherent light without using another member. Therefore, for example, compared with the case where incoherent light is obtained by using a laser diode as a light emitting element and making it enter into a fluorescent substance etc., it can have high light utilization efficiency. Furthermore, the apparatus can be reduced in size.

  The light emitting device 1000 can include a flat mirror 202 that reflects the first outgoing light 10 and guides it to the first parabolic mirror 212. Thereby, the outgoing lights 10 and 12 traveling in opposite directions can be made incident on the first parabolic mirror 212 and the second parabolic mirror 222, respectively. That is, both the first outgoing light 10 and the second outgoing light 12 traveling in opposite directions can be used. Therefore, the light use efficiency of the light 10 and 12 emitted from the light emitting element 100 can be increased.

  The light emitting device 1000 can include a first parabolic mirror 212 and a second parabolic mirror 222. Thereby, since the 1st reflected light 20 and the 2nd reflected light 22 can be made into parallel light, the structure of a back | latter stage optical system can be simplified.

In the light emitting device 1000, the optical axis to _{Q 1} first parabolic mirror 212, the optical axis _{Q 2} of the second parabolic mirror 222 may be parallel. Accordingly, the traveling direction of the first reflected light 20 and the traveling direction of the second reflected light 22 can be the same direction. Thereby, the configuration of the subsequent optical system can be simplified, and the optical axis alignment of the subsequent optical system can be facilitated.

  In the light emitting device 1000, the frame 300 can be formed of a material that is transmissive to the wavelengths of the emitted light 10 and 12. Therefore, since the absorption loss of the light 10, 12, 20, 22 in the frame 300 can be reduced, higher light utilization efficiency can be achieved.

2. Method for Manufacturing Light-Emitting Device Next, an example of a method for manufacturing the light-emitting device 1000 will be described with reference to the drawings. However, the method is not limited to the following example.

  Next, a method for manufacturing the light emitting device according to this embodiment will be described with reference to the drawings. 5 and 6 are cross-sectional views schematically showing the manufacturing process of the light emitting device 1000 according to this embodiment.

  As shown in FIG. 5, 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 on the substrate 102. As a method for epitaxial growth, for example, MOCVD (Metal Organic Chemical Vapor Deposition) method, MBE (Molecular Beam Epitaxy) method or the like can be used.

  As shown in FIG. 6, the contact layer 110 and the second cladding layer 108 are patterned. The patterning is performed using, for example, a photolithography technique and an etching technique. By this step, the columnar portion 111 can be formed.

  As shown in FIG. 3, the insulating part 116 is formed so as to cover the side surface of the columnar part 111. Specifically, first, an insulating layer (not shown) is formed above the second cladding layer 108 (including on the contact layer 110) by, for example, a CVD (Chemical Vapor Deposition) method, a coating method, or the like. Next, the upper surface of the contact layer 110 is exposed using, for example, an etching technique. Through the above steps, the insulating portion 116 can be formed.

  Next, the second electrode 114 is formed on the contact layer 110 and the insulating portion 116. The second electrode 114 is formed by, for example, a vacuum evaporation method. Next, the first electrode 112 is formed under the lower surface of the substrate 102. The manufacturing method of the 1st electrode 112 is the same as the illustration of the manufacturing method of the 2nd electrode 114 mentioned above, for example. Note that the order of forming the first electrode 112 and the second electrode 114 is not particularly limited.

  Through the above steps, the light-emitting element 100 can be manufactured.

  As shown in FIG. 1, the light emitting element 100, the first optical element 200, the second optical element 210, and the third optical element 220 are fixed to the frame body 300. Specifically, for example, the light emitting element 100 and the optical elements 200, 210, and 220 are fixed to the frame 300 using an adhesive (not shown) or the like.

  Through the above steps, the light-emitting device 1000 can be manufactured.

3. Modification of Light Emitting Device Next, a modification of the light emitting device according to the present embodiment will be described with reference to the drawings. FIG. 7 is a cross-sectional view schematically showing a light emitting device 1001 according to this modification, and corresponds to FIG. Hereinafter, in the light emitting device 1001 according to the present modification, members having the same functions as those of the constituent members of the light emitting device 1000 are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the example of the light emitting device 1000, as shown in FIG. 3, the light emitting element 100 has a refractive index difference in a region where the insulating portion 116 and the insulating portion 116 are not formed, that is, a region where the columnar portion 111 is formed. A refractive index waveguide type that provides and confines light has been described. On the other hand, the light-emitting element 100 of the light-emitting device 1001 can be of a gain waveguide type in which the columnar portion 111 is formed so that no refractive index difference is provided, and the gain region 120 becomes a waveguide region as it is.

  In the light emitting device 1001, as shown in FIG. 7, the contact layer 110 and the second cladding layer 108 do not constitute a columnar portion, and no insulating portion is formed on the side thereof. The insulating part 116 is formed on the contact layer 110 other than above the gain region 120. That is, the insulating part 116 has an opening above the gain region 120, and the upper surface of the contact layer 110 is exposed in the opening. The second electrode 114 is formed on the exposed contact layer 110 and the insulating portion 116. The contact surface between the second electrode 114 and the contact layer 110 has the same planar shape as that of the gain region 160. In the illustrated example, the current path between the electrodes 112 and 114 is determined by the planar shape of the contact surface between the second electrode 114 and the contact layer 110, and as a result, the planar shape of the gain region 120 can be determined. . Although not shown, the second electrode 114 may not be formed on the insulating portion 116 but may be formed only on the contact layer 110 above the gain region 120.

  According to the light emitting device 1001, like the light emitting device 1000, the light emitting element 100 can directly emit incoherent light without passing through other members, and the first emitted light 10 and the second emitted light 12 can be emitted. Since it can be utilized, it can have high light utilization efficiency.

4). Next, the projector 1100 according to this embodiment will be described. FIG. 8 is a diagram schematically showing a projector 1100 according to this embodiment. In FIG. 8, the casing that configures the projector 1100 is omitted for convenience.

  In the projector 1100, the red light source (light emitting device) 1000R, the green light source (light emitting device) 1000G, and the blue light source (light emitting device) 1000B that emit red light, green light, and blue light are the light emitting device 1000 described above.

  The projector 1100 includes transmissive liquid crystal light valves (light modulation devices) 1004R, 1004G, and 1004B that modulate light emitted from the light sources 1000R, 1000G, and 1000B in accordance with image information, and liquid crystal light valves 1004R, 1004G, and 1004B, respectively. A projection lens (projection device) 1008 for enlarging and projecting the image formed on the screen (display surface) 1010. In addition, the projector 1100 can include a cross dichroic prism (color light combining unit) 1006 that combines the light emitted from the liquid crystal light valves 1004R, 1004G, and 1004B and guides the light to the projection lens 1008.

  Further, in order to make the illuminance distribution of the light emitted from the light sources 1000R, 1000G, and 1000B uniform, the projector 1000 includes the uniformizing optical systems 1002R, 1002G, and 1002B on the downstream side of the light paths from the light sources 1000R, 1000G, and 1000B. The liquid crystal light valves 1004R, 1004G, and 1004B are illuminated with light that has been provided and has a uniform illuminance distribution. The uniformizing optical systems 1002R, 1002G, and 1002B are configured by, for example, a hologram 1002a and a field lens 1002b.

  The three colored lights modulated by the liquid crystal light valves 1004R, 1004G, and 1004B are incident on the cross dichroic prism 1006. 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 1010 by the projection lens 1006 which is a projection optical system, and an enlarged image is displayed.

  Further, although a transmissive liquid crystal light valve is used as the light modulator, 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 reflective liquid crystal light valve and a digital micromirror device. Further, the configuration of the projection optical system is appropriately changed depending on the type of light valve used.

  Further, the light emitting device 1000 is a scanning type having scanning means that is an image forming apparatus that displays an image of a desired size on a display surface by scanning light from a light source (light emitting device) 1000 on a screen. The present invention can also be applied to a light emitting device of an image display device (projector).

  The projector 1100 according to this embodiment can include the light emitting devices (red light source 1000R, green light source 1000G, blue light source 1000B) according to this embodiment. Therefore, according to the projector 1100, a light-emitting device that has high light utilization efficiency and can obtain incoherent light can be used as a light source.

  In addition, embodiment mentioned above and a modification are examples, Comprising: It is not necessarily 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 will readily understand that many modifications are possible without substantially departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention.

10 First outgoing light, 12 Second outgoing light, 20 First reflected light, 22 Second reflected light,
100 light emitting device, 101 laminated structure, 102 substrate, 104 first cladding layer,
105 first surface, 106 active layer, 107 second surface, 108 second cladding layer,
110 contact layer, 112 first electrode, 114 second electrode, 116 insulating portion,
120 gain region, 122 first exit surface, 124 second exit surface, 200 first optical element,
202 plane mirror, 210 second optical element, 212 first parabolic mirror,
220 third optical element, 222 second parabolic mirror, 300 frame,
1000, 1001 light emitting device, 1100 projector, 1002 homogenizing optical system,
1002a hologram, 1002b field lens,
1004 Liquid crystal light valve, 1006 Cross dichroic prism,
1008 Projection lens, 1010 screen

Claims (4)

A light emitting element formed of a super luminescent diode, and the light emitting element having a first emission surface and the second emission surface to emit the light traveling toward the opposite directions to each other,
A plane mirror that reflects light emitted from the first emission surface;
A first parabolic mirror that converts light reflected by the plane mirror into parallel light;
A second parabolic mirror that converts light emitted from the second emission surface into parallel light;
Including
The first emission surface is disposed at a position symmetrical to the focal point of the first paraboloidal mirror with respect to the plane mirror.
The second exit surface is disposed at a focal point of the second parabolic mirror;
The light emitting device, wherein an optical axis of the first parabolic mirror and an optical axis of the second parabolic mirror are parallel. In claim 1,
And a frame for fixing the light emitting element, the plane mirror, the first parabolic mirror, and the second parabolic mirror,
The light emitting device, wherein the frame is formed of a material that is transmissive to light emitted from the first emission surface and the second emission surface. In claim 1 or 2,
The first parabolic mirror and the second parabolic mirror are integrally formed with a light emitting device. A light emitting device according to any one of claims 1 to 3,
A light modulation device that modulates light emitted from the light emitting device according to image information;
A projection device for projecting an image formed by the light modulation device;
Including projector.

Images