JP2021136325A - Light emitting device and projector - Google Patents

Abstract

To provide a light emitting device that can reduce the water content in contact with columnar parts.SOLUTION: A light emitting device has: a substrate; a laminate that is provided on the substrate and has a plurality of columnar parts; electrodes that are provided on the laminate; and a coating layer that covers the electrodes. The columnar part has a first semiconductor layer, a second semiconductor layer that is different in conductivity type from the first semiconductor layer, and a light emitting layer that is provided between the first semiconductor layer and the second semiconductor layer. The coating layer is a hafnium oxide layer or a layer including a silane coupling agent.SELECTED DRAWING: Figure 1

Description

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

Semiconductor lasers are expected as next-generation light sources with high brightness. In particular, semiconductor lasers having nanostructures called nanocolumns, nanowires, nanorods, nanopillars, etc. are expected to be able to realize a light emitting device that can obtain high-power light emission at a narrow radiation angle due to the effect of photonic crystals.

For example, Patent Document 1 describes a compound semiconductor light emitting device including a plurality of GaN nanocolumns having an n-type GaN layer, a light emitting layer, and a p-type GaN layer.

Japanese Unexamined Patent Publication No. 2009-152474

In such a light emitting element, it is desired to prevent the invasion of moisture. When moisture invades and comes into contact with the GaN nanocolumn, the GaN nanocolumn may be corroded and deteriorated.

One aspect of the light emitting device according to the present invention is
With the board
A laminate provided on the substrate and having a plurality of columnar portions,
The electrodes provided on the laminate and
A coating layer that covers the electrodes and
Have,
The columnar part is
The first semiconductor layer and
A second semiconductor layer having a different conductive type from the first semiconductor layer,
A light emitting layer provided between the first semiconductor layer and the second semiconductor layer,
Have,
The coating layer is a hafnium oxide layer or a layer containing a silane coupling agent.

One aspect of the projector according to the present invention is
It has one aspect of the light emitting device.

The cross-sectional view which shows typically the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The cross-sectional view which shows typically the manufacturing process of the light emitting device which concerns on this embodiment. The figure which shows typically the projector which concerns on this embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unreasonably limit the content of the present invention described in the claims. Moreover, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. Light-emitting device First, the light-emitting device according to the present embodiment will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing a light emitting device 100 according to the present embodiment.

As shown in FIG. 1, the light emitting device 100 includes, for example, a substrate 10, a laminate 20, a first insulating layer 40, a second insulating layer 42, a first electrode 50, a second electrode 52, and a second electrode. It has one coating layer 60 and a second coating layer 62.

The substrate 10 has, for example, a plate-like shape. The substrate 10 is, for example, a Si substrate, a GaN substrate, a sapphire substrate, or the like.

The laminate 20 is provided on the substrate 10. In the illustrated example, the laminate 20 is provided on the substrate 10. The laminate 20 has, for example, a buffer layer 22, a mask layer 24, and a columnar portion 30.

In the present specification, when the light emitting layer 34 is used as a reference in the stacking direction of the first semiconductor layer 32 and the light emitting layer 34 (hereinafter, also simply referred to as “stacking direction”), the light emitting layer 34 to the second semiconductor layer The direction toward 36 will be referred to as “up”, and the direction from the light emitting layer 34 toward the first semiconductor layer 32 will be referred to as “down”. Further, the direction orthogonal to the stacking direction is also referred to as an "in-plane direction".

The buffer layer 22 is provided on the substrate 10. The buffer layer 22 is, for example, an n-type GaN layer doped with Si.

The mask layer 24 is provided on the buffer layer 22. The mask layer 24 is a selective growth film for growing the columnar portion 30. The mask layer 24 is, for example, a silicon oxide layer, a titanium layer, a titanium oxide layer, an aluminum oxide layer, or the like.

The columnar portion 30 is provided on the buffer layer 22. The columnar portion 30 has a columnar shape protruding upward from the buffer layer 22. The columnar portion 30 is also called, for example, a nanocolumn, a nanowire, a nanorod, or a nanopillar. The planar shape of the columnar portion 30 is, for example, a polygon such as a regular hexagon or a circle.

The diameter of the columnar portion 30 is, for example, 50 nm or more and 500 nm or less. By setting the diameter of the columnar portion 30 to 500 nm or less, a high-quality crystal light emitting layer 34 can be obtained, and distortion inherent in the light emitting layer 34 can be reduced. As a result, the light generated in the light emitting layer 34 can be amplified with high efficiency. The diameters of the plurality of columnar portions 30 are, for example, equal to each other.

The "diameter of the columnar portion" is the diameter when the planar shape of the columnar portion 30 is a circle, and is the diameter of the minimum inclusion circle when the planar shape of the columnar portion 30 is not a circle. For example, the diameter of the columnar portion 30 is the diameter of the smallest circle including the polygon when the planar shape of the columnar portion 30 is a polygon, and when the planar shape of the columnar portion 30 is an ellipse, the ellipse is used. It is the diameter of the smallest circle contained inside.

A plurality of columnar portions 30 are provided. The distance between the adjacent columnar portions 30 is, for example, 1 nm or more and 500 nm or less. In the illustrated example, there is a gap between the adjacent columnar portions 30. Although not shown, a light propagation layer for propagating the light generated by the light emitting layer 34 may be provided between the adjacent columnar portions 30. The light propagation layer is, for example, a silicon oxide layer, an aluminum oxide layer, a titanium oxide layer, or the like.

The plurality of columnar portions 30 are arranged in a predetermined direction at a predetermined pitch in a plan view from the stacking direction (hereinafter, also simply referred to as "in a plan view"). The plurality of columnar portions 30 are arranged in a triangular lattice pattern. The arrangement of the plurality of columnar portions 30 is not particularly limited, and may be arranged in a square lattice pattern. The plurality of columnar portions 30 can exhibit the effect of photonic crystals.

The "columnar portion pitch" is the distance between the centers of the columnar portions 30 adjacent to each other along a predetermined direction. The "center of the columnar portion" is the center of the circle when the planar shape of the columnar portion 30 is a circle, and the center of the minimum inclusion circle when the planar shape of the columnar portion 30 is not a circle. .. For example, the center of the columnar portion 30 is the center of the smallest circle including the polygon when the planar shape of the columnar portion 30 is a polygon, and when the planar shape of the columnar portion 30 is an ellipse, the ellipse is used. It is the center of the smallest circle contained inside.

The columnar portion 30 has a first semiconductor layer 32, a light emitting layer 34, and a second semiconductor layer 36.

The first semiconductor layer 32 is provided on the buffer layer 22. The first semiconductor layer 32 is provided between the substrate 10 and the light emitting layer 34. The first semiconductor layer 32 is an n-type semiconductor layer. The first semiconductor layer 32 is, for example, an n-type GaN layer doped with Si.

The light emitting layer 34 is provided on the first semiconductor layer 32. The light emitting layer 34 is provided between the first semiconductor layer 32 and the second semiconductor layer 36. The light emitting layer 34 generates light by injecting an electric current. The light emitting layer 34 has, for example, a multiple quantum well structure in which a quantum well structure composed of an i-type GaN layer that is not doped with impurities and an i-type InGaN layer is superposed.

The second semiconductor layer 36 is provided on the light emitting layer 34. The second semiconductor layer 36 is a layer having a different conductive type from the first semiconductor layer 32. The second semiconductor layer 36 is a p-type semiconductor layer. The second semiconductor layer 36 is, for example, a p-type GaN layer doped with Mg. The first semiconductor layer 32 and the second semiconductor layer 36 are clad layers having a function of confining light in the light emitting layer 34.

The first insulating layer 40 is provided on the columnar portion 30. In the illustrated example, the first insulating layer 40 is provided with an opening, and the opening is provided with the first conductive layer 54 of the second electrode 52. The first insulating layer 40 is, for example, a silicon oxide layer.

The second insulating layer 42 is provided so as to cover the columnar portion 30. In the illustrated example, the second insulating layer 42 is provided on the buffer layer 22, the mask layer 24, the first insulating layer 40, and the first electrode 50. The second insulating layer 42 is, for example, a silicon oxide layer.

The first electrode 50 is provided on the buffer layer 22. The buffer layer 22 may be in ohmic contact with the first electrode 50. The first electrode 50 is electrically connected to the first semiconductor layer 32. In the illustrated example, the first electrode 50 is electrically connected to the first semiconductor layer 32 via the buffer layer 22. The first electrode 50 is one electrode for injecting a current into the light emitting layer 34. As the first electrode 50, for example, one in which a Cr layer, a Ni layer, and an Au layer are laminated in this order from the buffer layer 22 side is used.

The second electrode 52 is provided on the side of the laminated body 20 opposite to the substrate 10. In the illustrated example, the second electrode 52 is connected to the second semiconductor layer 36. The second electrode 52 is the other electrode for injecting a current into the light emitting layer 34. The second electrode 52 has, for example, a first conductive layer 54, a second conductive layer 56, and a third conductive layer 58.

The first conductive layer 54 is provided on the second semiconductor layer 36. Here, FIG. 2 is a cross-sectional view schematically showing the light emitting device 100. FIG. 2 illustrates the vicinity of the first conductive layer 54. As shown in FIG. 2, the surface of the first conductive layer 54 has an uneven shape reflecting the shapes of the plurality of columnar portions 30. For convenience, FIG. 1 does not show the uneven shape of the surface.

The thickness of the first conductive layer 54 is, for example, 20 nm or less, preferably 5 nm or more and 10 nm or less. When the thickness of the first conductive layer 54 is 20 nm or less, the absorption of light (light generated by the light emitting layer 34) in the first conductive layer 54 can be reduced. The first conductive layer 54 is, for example, one in which a Pd layer, a Pt layer, and an Au layer are laminated in this order from the second semiconductor layer 36 side.

The second conductive layer 56 is provided on the first conductive layer 54. In the example shown in FIG. 1, the second conductive layer 56 is provided on the first conductive layer 54 and the second insulating layer 42. As shown in FIG. 2, the surface of the second conductive layer 56 has an uneven shape reflecting the shape of the first conductive layer 54. The thickness of the second conductive layer 56 (the thickness of the portion of the second conductive layer 56 provided on the first conductive layer 54) is, for example, 10 nm or more and 100 nm or less. The second conductive layer 56 is, for example, an ITO (Indium Tin Oxide) layer.

As shown in FIG. 1, the third conductive layer 58 is provided on the second conductive layer 56. In the illustrated example, the third conductive layer 58 is provided in a portion of the second conductive layer 56 provided on the second insulating layer 42. The third conductive layer 58 is, for example, one in which a Cr layer, a Ni layer, and an Au layer are laminated in this order from the second conductive layer 56 side.

The first coating layer 60 covers the second electrode 52. In the illustrated example, the first coating layer 60 covers the second conductive layer 56, the third conductive layer 58, the second insulating layer 42, the buffer layer 22, and the substrate 10. As shown in FIG. 2, the surface of the first coating layer 60 has an uneven shape reflecting the shape of the second conductive layer 56.

The thickness of the first coating layer 60 is, for example, 1 nm or more and 10 nm or less, preferably 5 nm. When the thickness of the first coating layer 60 is 10 nm or less, the absorption of light in the first coating layer 60 can be reduced.

The first coating layer 60 is, for example, an aluminum oxide layer or a silicon nitride layer. The first coating layer 60 has a high barrier property against oxygen. As a result, it is possible to prevent the columnar portion 30 from being oxidized. When the columnar portion 30 is oxidized, the luminous efficiency is lowered.

The second coating layer 62 covers the second electrode 52. In the example shown in FIG. 1, the second coating layer 62 covers the second conductive layer 56, the third conductive layer 58, the second insulating layer 42, the buffer layer 22, and the substrate 10 via the first coating layer 60. doing. Although not shown, the first coating layer 60 may not be provided. In this case, the second coating layer 62 directly coats the second conductive layer 56, the third conductive layer 58, the second insulating layer 42, the buffer layer 22, and the substrate 10. As described above, "A covers B" means that A indirectly covers B through another layer and A directly covers B without going through another layer. Including the case where B is covered.

As shown in FIG. 2, the surface 62a of the second coating layer 62 has an uneven shape reflecting the shape of the first coating layer 60. The second coating layer 62 has a plurality of convex portions 64 on the surface 62a. The surface 62a is a surface of the second coating layer 62 opposite to the substrate 10. The diameter D1 of the convex portion 64 on the most substrate 10 side is larger than, for example, the diameter D2 of the convex portion 64 on the side opposite to the most substrate 10. That is, the convex portion 64 has a shape in which the diameter decreases from the substrate 10 side toward the side opposite to the substrate 10. In a plan view, the convex portion 64 overlaps the columnar portion 30. A plurality of convex portions 64 are provided corresponding to the plurality of columnar portions 30.

The "diameter of the convex portion" is the diameter when the planar shape of the convex portion 64 is a circle, and is the diameter of the minimum inclusion circle when the planar shape of the convex portion 64 is not a circle. For example, the diameter of the convex portion 64 is the diameter of the smallest circle including the polygon when the planar shape of the convex portion 64 is a polygon, and when the planar shape of the convex portion 64 is an ellipse, the ellipse is used. It is the diameter of the smallest circle contained inside.

The thickness of the second coating layer 62 is, for example, 1 nm or more and 10 nm or less, preferably 5 nm. When the thickness of the second coating layer 62 is 10 nm or less, the absorption of light in the second coating layer 62 can be reduced. The first coating layer 60 and the second coating layer 62 may function as antireflection films with respect to the light generated by the light emitting layer 34.

The second coating layer 62 is a hafnium oxide layer or a layer containing a silane coupling agent. The layer containing the silane coupling agent contains, for example, silicon oxide. Specifically, the second coating layer 62 is a hafnium oxide layer or a layer containing a silane coupling agent and silicon oxide. The layer containing the silane coupling agent and silicon oxide forms a SAM (Self-Assembled Monolayer) by a silane coupling reaction. Examples of the silane coupling agent include olefilsilane, acroyloxyalkylsilane, aminoalkylsilane, alkylsilane, arylsilane, arylalkylsilane, fluoroalkylsilane, and fluoroarylsilane. The second coating layer 62 is a moisture-resistant protective film that protects the columnar portion 30 from moisture. The heat resistance of the hafnium oxide layer is higher than that of the layer containing the silane coupling agent and silicon oxide.

The refractive index of the second coating layer 62 is lower than, for example, the refractive index of the second electrode 52. The refractive index of the second coating layer 62 is lower than, for example, the refractive index of the second conductive layer 56. The refractive index of the second coating layer 62 is lower than, for example, the refractive index of the first coating layer 60. The refractive index of the first coating layer 60 is lower than, for example, the refractive index of the second conductive layer 56. For example, when the second coating layer 62 is a layer containing a silane coupling agent and silicon oxide, the first coating layer 60 is an aluminum oxide layer, and the second conductive layer 56 is an ITO layer, the second coating layer 62 The refractive index of the first coating layer 60 is lower than that of the first coating layer 60, and the refractive index of the first coating layer 60 is lower than that of the second conductive layer 56.

In the light emitting device 100, the pin diode is composed of the p-type second semiconductor layer 36, the i-type light emitting layer 34, and the n-type first semiconductor layer 32. In the light emitting device 100, when a forward bias voltage of a pin diode is applied between the first electrode 50 and the second electrode 52, a current is injected into the light emitting layer 34 and recombination of electrons and holes in the light emitting layer 34. Occurs. This recombination causes light emission. The light generated in the light emitting layer 34 propagates in the in-plane direction by the first semiconductor layer 32 and the second semiconductor layer 36, forms a standing wave by the effect of the photonic crystal by the plurality of columnar portions 30, and forms a standing wave. The laser oscillates by receiving the gain. Then, the light emitting device 100 emits the +1st-order diffracted light and the -1st-order diffracted light as laser light in the stacking direction.

Although the InGaN-based light emitting layer 34 has been described above, various material systems capable of emitting light by injecting a current can be used as the light emitting layer 34 according to the wavelength of the emitted light. For example, semiconductor materials such as AlGaN-based, AlGaAs-based, InGaAs-based, InGaAsP-based, InP-based, GaP-based, and AlGaP-based can be used.

The light emitting device 100 has the following effects, for example.

The light emitting device 100 has a second coating layer 62 that covers the second electrode 52, and the second coating layer 62 is a hafnium oxide layer or a layer containing a silane coupling agent. Therefore, in the light emitting device 100, the water content in contact with the columnar portion 30 can be reduced as compared with the case where the second coating layer is not provided. As a result, the light emitting device 100 can have high reliability and can operate stably for a long period of time with high output.

In the light emitting device 100, the second coating layer 62 has a plurality of convex portions 64 on the surface 62a, and the diameter D1 of the convex portion 64 on the most substrate 10 side is the diameter of the convex portion 64 on the side opposite to the most substrate 10. Larger than D2. That is, the convex portion 64 has a shape in which the diameter decreases from the substrate 10 side toward the side opposite to the substrate 10. As a result, the reflectance of the surface 62a with respect to the light generated in the light emitting layer 34 and emitted in the stacking direction can be reduced. That is, by providing the surface 62a with a plurality of convex portions 64, as shown in the graph of FIG. 2, the average refractive index can be continuously changed, and a moth-eye structure that reduces the reflectance can be realized. .. Therefore, in the light emitting device 100, the light generated in the light emitting layer 34 can be efficiently emitted in the stacking direction. Further, the speckle of the light emitted from the light emitting device 100 can be reduced by the plurality of convex portions 64.

In the graph of FIG. 2, the horizontal axis indicates the average refractive index in the in-plane direction, and the vertical axis indicates the position in the stacking direction.

In the light emitting device 100, the convex portion 64 overlaps with the columnar portion 30 in a plan view. In the light emitting device 100, a plurality of convex portions 64 can be formed on the surface 62a of the second coating layer 62, reflecting the shapes of the plurality of columnar portions 30.

In the light emitting device 100, the refractive index of the second coating layer 62 is lower than the refractive index of the second electrode 52. Therefore, in the light emitting device 100, for example, as compared with the case where the refractive index of the second coating layer is equal to or higher than the refractive index of the second electrode, the reflection of the surface 62a on the light generated in the light emitting layer 34 and emitted in the stacking direction is reflected. The rate can be reduced.

In the light emitting device 100, the second coating layer 62 covers the substrate 10. Therefore, in the light emitting device 100, the moisture entering from the substrate 10 side can be reduced as compared with the case where the second coating layer does not cover the substrate.

2. Manufacturing Method of Light Emitting Device Next, a manufacturing method of the light emitting device 100 according to the present embodiment will be described with reference to the drawings. 3 and 4 are cross-sectional views schematically showing a manufacturing process of the light emitting device 100 according to the present embodiment.

As shown in FIG. 3, the buffer layer 22 is epitaxially grown on the substrate 10. Examples of the method for epitaxial growth include a MOCVD (Metal Organic Chemical Vapor Deposition) method and an MBE (Molecular Beam Epitaxy) method.

Next, the mask layer 24 is formed on the buffer layer 22. The mask layer 24 is formed by, for example, a CVD (Chemical Vapor Deposition) method or a sputtering method. Next, the mask layer 24 is patterned to form a plurality of openings. Patterning is performed, for example, by electron beam lithography and dry etching.

As shown in FIG. 4, the first semiconductor layer 32, the light emitting layer 34, and the second semiconductor layer 36 are epitaxially grown on the buffer layer 22 using the mask layer 24 as a mask. Examples of the method for epitaxial growth include the MOCVD method and the MBE method. As a result, the columnar portion 30 can be formed.

Next, the first electrode 50 is formed on the buffer layer 22. The first electrode 50 is formed by, for example, a vacuum vapor deposition method.

Next, the first insulating layer 40 is formed on the columnar portion 30. The first insulating layer 40 is formed by, for example, an ALD (Atomic layer deposition) method.

Next, the first conductive layer 54 is formed on the columnar portion 30. The first conductive layer 54 is formed by, for example, a CVD method or a vacuum vapor deposition method.

Next, the second insulating layer 42 is formed on the first insulating layer 40, the mask layer 24, the buffer layer 22, and the first electrode 50. The second insulating layer 42 is formed by, for example, a CVD method.

Next, the second conductive layer 56 is formed on the first conductive layer 54 and the second insulating layer 42. Next, the third conductive layer 58 is formed on the second conductive layer 56. The second conductive layer 56 and the third conductive layer 58 are formed by, for example, a CVD method or a vacuum vapor deposition method. As a result, the second electrode 52 can be formed.

As shown in FIG. 1, a first coating layer 60 that covers the second conductive layer 56, the third conductive layer 58, the second insulating layer 42, the buffer layer 22, and the substrate 10 is formed. Next, the second coating layer 62 that covers the first coating layer 60 is formed. The first coating layer 60 and the second coating layer 62 are formed by, for example, an ALD method or a CVD method. Since the ALD method and the CVD method have high coverage, the first coating layer 60 and the second coating layer 62 can be formed on the entire surface.

By the above steps, the light emitting device 100 can be manufactured.

3. 3. Projector Next, the projector according to the present embodiment will be described with reference to the drawings. FIG. 5 is a diagram schematically showing the projector 900 according to the present embodiment.

The projector 900 has, for example, a light emitting device 100 as a light source.

The projector 900 has a housing (not shown) and a red light source 100R, a green light source 100G, and a blue light source 100B that emit red light, green light, and blue light, respectively, provided in the housing. For convenience, FIG. 5 simplifies the red light source 100R, the green light source 100G, and the blue light source 100B.

The projector 900 further includes a first optical element 902R, a second optical element 902G, a third optical element 902B, a first optical modulator 904R, and a second optical modulator 904G, which are provided in the housing. , A third optical modulator 904B and a projection apparatus 908. The first light modulation device 904R, the second light modulation device 904G, and the third light modulation device 904B are, for example, transmissive liquid crystal light bulbs. The projection device 908 is, for example, a projection lens.

The light emitted from the red light source 100R is incident on the first optical element 902R. The light emitted from the red light source 100R is collected by the first optical element 902R. The first optical element 902R may have a function other than focusing. The same applies to the second optical element 902G and the third optical element 902B, which will be described later.

The light collected by the first optical element 902R is incident on the first light modulator 904R. The first light modulator 904R modulates the incident light according to the image information. Then, the projection device 908 enlarges the image formed by the first light modulation device 904R and projects it on the screen 910.

The light emitted from the green light source 100G is incident on the second optical element 902G. The light emitted from the green light source 100G is collected by the second optical element 902G.

The light collected by the second optical element 902G is incident on the second optical modulator 904G. The second light modulator 904G modulates the incident light according to the image information. Then, the projection device 908 enlarges the image formed by the second light modulation device 904G and projects it on the screen 910.

The light emitted from the blue light source 100B is incident on the third optical element 902B. The light emitted from the blue light source 100B is collected by the third optical element 902B.

The light collected by the third optical element 902B is incident on the third optical modulator 904B. The third light modulator 904B modulates the incident light according to the image information. Then, the projection device 908 enlarges the image formed by the third light modulation device 904B and projects it on the screen 910.

Further, the projector 900 can have a cross dichroic prism 906 that synthesizes the light emitted from the first light modulation device 904R, the second light modulation device 904G, and the third light modulation device 904B and guides the light emitted from the third light modulation device 904B to the projection device 908. ..

The three colored lights modulated by the first optical modulator 904R, the second optical modulator 904G, and the third optical modulator 904B are incident on the cross dichroic prism 906. The cross dichroic prism 906 is formed by laminating four right-angled prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged on the inner surface thereof. Three colored lights are combined by these dielectric multilayer films to form light representing a color image. Then, the combined light is projected onto the screen 910 by the projection device 908, and an enlarged image is displayed.

The red light source 100R, the green light source 100G, and the blue light source 100B control the light emitting device 100 as a pixel of an image according to the image information, so that the first light modulation device 904R, the second light modulation device 904G, and the second light light source 100B are controlled. 3 The image may be directly formed without using the optical modulator 904B. Then, the projection device 908 may magnify and project the image formed by the red light source 100R, the green light source 100G, and the blue light source 100B onto the screen 910.

Further, in the above example, a transmissive liquid crystal light bulb is used as the light modulation device, but a light bulb other than the liquid crystal may be used, or a reflective light bulb may be used. Examples of such a light bulb include a reflective liquid crystal light bulb and a digital micromirror device. In addition, the configuration of the projection device is appropriately changed depending on the type of light bulb used.

Further, a light source device of a scanning type image display device having a scanning means which is an image forming device for displaying an image of a desired size on a display surface by scanning the light from the light source on the screen. It can also be applied to.

The light emitting device according to the above-described embodiment can be used in addition to the projector. Applications other than projectors include, for example, indoor / outdoor lighting, display backlights, laser printers, scanners, in-vehicle lights, automobile head lamps, light-using sensing devices, communication devices, and other light sources.

The above-described embodiments and modifications are merely examples, and the present invention is not limited thereto. For example, each embodiment and each modification can be combined as appropriate.

The present invention includes a configuration substantially the same as the configuration described in the embodiment, for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect. The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention also includes a configuration that exhibits the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. The present invention also includes a configuration in which a known technique is added to the configuration described in the embodiment.

The following contents are derived from the above-described embodiments and modifications.

One aspect of the light emitting device is
With the board
A laminate provided on the substrate and having a plurality of columnar portions,
The electrodes provided on the laminate and
A coating layer that covers the electrodes and
Have,
The columnar part is
The first semiconductor layer and
A second semiconductor layer having a different conductive type from the first semiconductor layer,
A light emitting layer provided between the first semiconductor layer and the second semiconductor layer,
Have,
The coating layer is a hafnium oxide layer or a layer containing a silane coupling agent.

According to this light emitting device, it is possible to reduce the water content in contact with the columnar portion.

In one aspect of the light emitting device,
The coating layer has a plurality of protrusions on the surface and has a plurality of protrusions.
The diameter of the convex portion on the most substrate side may be larger than the diameter of the convex portion on the side opposite to the substrate.

According to this light emitting device, it is possible to reduce the reflectance of the surface with respect to the light generated in the light emitting layer and emitted in the stacking direction.

In one aspect of the light emitting device,
In a plan view from the stacking direction of the first semiconductor layer and the light emitting layer, the convex portion may overlap with the columnar portion.

According to this light emitting device, a plurality of convex portions can be formed on the surface of the second coating layer by reflecting the shapes of the plurality of columnar portions.

In one aspect of the light emitting device,
The refractive index of the coating layer may be lower than the refractive index of the electrode.

According to this light emitting device, it is possible to reduce the reflectance of the surface with respect to the light generated in the light emitting layer and emitted in the stacking direction.

In one aspect of the light emitting device,
The layer containing the silane coupling agent may contain silicon oxide.

In one aspect of the light emitting device,
The coating layer may cover the substrate.

According to this light emitting device, it is possible to reduce the moisture entering from the substrate side.

One aspect of the projector is
It has one aspect of the light emitting device.

10 ... substrate, 20 ... laminate, 22 ... buffer layer, 24 ... mask layer, 30 ... columnar portion, 32 ... first semiconductor layer, 34 ... light emitting layer, 36 ... second semiconductor layer, 40 ... first insulating layer, 42 ... 2nd insulating layer, 50 ... 1st electrode, 52 ... 2nd electrode, 54 ... 1st conductive layer, 56 ... 2nd conductive layer, 58 ... 3rd conductive layer, 60 ... 1st coating layer, 62 ... 2 coating layer, 62a ... surface, 64 ... convex portion, 100 ... light emitting device, 900 ... projector, 902R ... first optical element, 902G ... second optical element, 902B ... third optical element, 904R ... first optical modulator , 904G ... 2nd optical modulator, 904B ... 3rd optical modulator, 906 ... Cross dichroic prism, 908 ... Projector, 910 ... Screen

Claims (7)

With the board
A laminate provided on the substrate and having a plurality of columnar portions,
The electrodes provided on the laminate and
A coating layer that covers the electrodes and
Have,
The columnar part is
The first semiconductor layer and
A second semiconductor layer having a different conductive type from the first semiconductor layer,
A light emitting layer provided between the first semiconductor layer and the second semiconductor layer,
Have,
The coating layer is a hafnium oxide layer or a layer containing a silane coupling agent, which is a light emitting device. In claim 1,
The coating layer has a plurality of protrusions on the surface and has a plurality of protrusions.
A light emitting device in which the diameter of the convex portion on the most substrate side is larger than the diameter of the convex portion on the side opposite to the substrate. In claim 2,
A light emitting device in which the convex portion overlaps the columnar portion in a plan view from the stacking direction of the first semiconductor layer and the light emitting layer. In any one of claims 1 to 3,
A light emitting device in which the refractive index of the coating layer is lower than the refractive index of the electrode. In any one of claims 1 to 4,
The layer containing the silane coupling agent is a light emitting device containing silicon oxide. In any one of claims 1 to 5,
The coating layer is a light emitting device that covers the substrate. A projector having the light emitting device according to any one of claims 1 to 6.

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