Patent Publication Number: US-2022238595-A1

Title: Light Emitting Apparatus, Method For Manufacturing Light Emitting Apparatus, And Projector

Description:
The present application is based on, and claims priority from JP Application Serial Number 2021-008543, filed Jan. 22, 2021, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a light emitting apparatus, a method for manufacturing the light emitting apparatus, and a projector. 
     2. Related Art 
     JP-A-2013-239718 discloses a light emitting apparatus including light emitting sections each formed of plurality of nanocolumns provided on a substrate. In the light emitting apparatus, the light emitting sections, which emit light beams having different colors, are formed on the substrate. 
     In the light emitting apparatus described above, it is conceivable that the light emitting sections, which emit light beams having different colors, have respective light emitting regions of different sizes. The size of each of the light emitting regions is determined by the diameter of an opening formed in a protective film that covers the light emitting section. It is therefore necessary to form a large opening in the protective film that covers a light emitting section having a large light emitting region and a small opening in the protective film that covers a light emitting section having a small light emitting region. 
     However, to form openings of different sizes in the protective films in an etching process, it is difficult to set a common etching rate. An etching period set so as to be suitable for an opening where the etching progresses quickly is not long enough for the other openings. Conversely, an etching period set so as to be suitable for an opening where the etching progresses slowly is too long for the other openings, so that the etching damages an underlying layer. 
     SUMMARY 
     To solve the problem described above, according to an aspect of the present disclosure, there is provided a light emitting apparatus including a substrate, a first light emitting section provided on the substrate, a second light emitting section provided on the substrate, a first electrode provided on a side of the first light emitting section that is a side opposite from the substrate, a second electrode provided on a side of the second light emitting section that is a side opposite from the substrate, a first protective layer that covers the first light emitting section and the first electrode, and a second protective layer that covers the second light emitting section and the second electrode. An area of the first electrode is greater than an area of the second electrode in a plan view viewed in a direction of a normal to the substrate. The first protective layer has a first through hole. The second protective layer has a second through hole. The first through hole has a first hole and a second hole located in a position shifted from the first hole toward the substrate. The second through hole has a third hole and a fourth hole located in a position shifted from the third hole toward the substrate. A first opening area of a first opening of the first hole, which is an opening farthest from the substrate, is greater than a second opening area of a second opening of the second hole, which is an opening closest to the substrate. A third opening area of a third opening of the third hole, which is an opening farthest from the substrate, is greater than a fourth opening area of a fourth opening of the fourth hole, which is an opening closest to the substrate. In the plan view, an outer edge of the second opening overlaps with the first electrode, and an outer edge of the fourth opening overlaps with the second electrode. The second opening area is greater than the fourth opening area. 
     According to another aspect of the present disclosure, there is provided a method for manufacturing a light emitting apparatus, the method including forming a first light emitting section and a second light emitting section on a substrate, forming a first electrode on a side of the first light emitting section that is a side opposite from the substrate, forming a second electrode having an area smaller than an area of the first electrode on a side of the second light emitting section that is a side opposite from the substrate, forming a first protective layer on the substrate so as to cover the first light emitting section and the first electrode, forming a second protective layer on the substrate so as to cover the second light emitting section and the second electrode, forming a first hole in a first position in the first protective layer where the first hole overlaps with the first electrode and another first hole in a second position in the second protective layer where the other first hole overlaps with the second electrode in a plan view viewed in a direction of a normal to the substrate, forming a second hole in a bottom surface of the first hole formed in the first position, the second hole having an opening area smaller than an opening area of the first hole, to form a first through hole that exposes part of the first electrode, and forming a third hole in a bottom surface of the first hole formed in the second position, the third hole having an opening area smaller than the opening area of the second hole, to form a second through hole that exposes part of the second electrode. 
     According to another aspect of the present disclosure, there is provided a projector including the light emitting apparatus according to the aspect described above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic configuration diagram of a projector according to an embodiment. 
         FIG. 2  is a plan view showing a schematic configuration of a light emitting device. 
         FIG. 3  shows the configurations of key parts of the light emitting device. 
         FIG. 4A  shows key parts in one of the steps of manufacturing a light emitting apparatus. 
         FIG. 4B  shows key parts in one of the steps of manufacturing the light emitting apparatus. 
         FIG. 4C  shows key parts in one of the steps of manufacturing the light emitting apparatus. 
         FIG. 4D  shows key parts in one of the steps of manufacturing the light emitting apparatus. 
         FIG. 4E  shows key parts in one of the steps of manufacturing the light emitting apparatus. 
         FIG. 5  is a cross-sectional view showing a configuration of a light emitting device according to a variation. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     An embodiment according to the present disclosure will be described below with reference to the drawings. In the following drawings, components are drawn at different dimensional scales in some cases for clarification of each of the components.  FIG. 1  is a schematic configuration diagram of a projector according to the present embodiment. 
     A projector  1  according to the present embodiment is a projection-type image display apparatus that displays an image on a screen SC, as shown in  FIG. 1 . The projector  1  includes a light emitting apparatus  12 , a light modulating apparatus  5 , and a projection optical apparatus  4 . The configuration of the light emitting apparatus  12  will be described later in detail. 
     An optical axis which coincides with a normal passing through the center of a light emitting region  12 R of the light emitting apparatus  12  and along which the chief ray of a luminous flux L outputted from the light emitting region  12 R travels is hereinafter referred to as an optical axis AX 1 . 
     The configuration of each of the apparatuses of the projector  1  will be described below by using an XYZ orthogonal coordinate system. The orthogonal coordinate system has an axis X parallel to the long sides of the light emitting region  12 R, which has a rectangular planar shape when viewed in the direction of the optical axis AX 1 , an axis Y parallel to the short sides of the light emitting region  12 R, and an axis Z perpendicular to the axes X and Y. The axis Z is parallel to the optical axis AX 1 . 
     The light modulating apparatus  5  modulates the luminous flux L outputted from the light emitting apparatus in accordance with image information to generate image light. The light modulating apparatus  5  includes a light-incident-side polarizer  6 , a liquid crystal display device  7 , and a light-exiting-side polarizer  8 . An image formation region  7 R of the liquid crystal display device  7  has a rectangular planar shape when viewed in the axis-Z direction. The light emitting region  12 R of the light emitting apparatus  12  has a rectangular planar shape as described above, and the planar shape of the image formation region  7 R is substantially similar to the planar shape of the light emitting region  12 R. The area of the light emitting region  12 R is equal to or slightly greater than the area of the image formation region  7 R. 
     The projection optical apparatus  4  projects the image light outputted from the light modulating apparatus  5  onto a projection receiving surface, such as the screen SC. The projection optical apparatus  4  is formed of a single projection lens or a plurality of projection lenses. 
     The light emitting apparatus  12  according to the present embodiment will be described below. 
     The light emitting apparatus  12  includes a light emitting device  20  and a heat sink  21 , as shown in  FIG. 1 . The light emitting device  20  has a first surface  20   a  and a second surface  20   b  and outputs the luminous flux L via the first surface  20   a . The heat sink  21  is provided at the second surface  20   b  of the light emitting device  20  to dissipate heat generated by the light emitting device  20 . The heat sink  21  may be omitted as required. 
       FIG. 2  is a plan view showing a schematic configuration of the light emitting device  20 .  FIG. 2  shows only part of light emitting sections  30  in the light emitting region  12 R of the light emitting device  20 , and does not show the other light emitting sections  30  for clarity of illustration. 
     The light emitting device  20  includes a plurality of light emitting sections  30  provided in an array as shown in  FIG. 2 . In the present embodiment, the light emitting sections are provided in a matrix along the axes X and Y. The plurality of light emitting sections  30  include red light emitting sections  30 R, which emit red light, green light emitting sections  30 G, which emit green light, and blue light emitting sections  30 B, which emit blue light. The light emitting apparatus  12  according to the present embodiment can form a self-luminous imager that forms video images with the light emitting sections  30  serving as pixels. 
     In the present embodiment, the white balance of the video images is adjusted by configuring the light emitting area of the blue light emitting sections  30 B to be larger than that of the red light emitting sections  30 R. The light emitting areas of the red light emitting sections  30 R and the green light emitting sections  30 G are set to be equal to each other. 
       FIG. 3  shows the configurations of key parts of the light emitting device  20 .  FIG. 3  shows a portion including the blue light emitting section  30 B and the red light emitting section  30 R out of the plurality of light emitting sections  30 . The upper part of  FIG. 3  is a plan view of the blue light emitting section  30 B and the red light emitting section  30 R viewed from the side +Z, and the lower part of  FIG. 3  is a cross-sectional view of the blue light emitting section  30 B and the red light emitting section  30 R. 
     The light emitting device  20  includes a base (substrate)  10 , a semiconductor layer  11 , the blue light emitting sections (first light emitting section)  30 B, the red light emitting sections (second light emitting section)  30 R, a first protective layer  51 , a second protective layer  52 , a lower-layer electrode  60 B, an upper-layer electrode (first electrode)  70 B, a drawn electrode  71 B, a lower-layer electrode  60 R, an upper-layer electrode (second electrode)  70 R, a drawn electrode  71 R, first wiring  81 , and second wiring  82 , as shown in  FIG. 3 . 
     In the description of the present embodiment, the direction in which nanocolumns that will be described later and form the blue light emitting sections  30 B and red light emitting sections  30 R are laminated on the base  10  is called an “upper” side of the axis-Z direction, and the direction from the base  10  toward the side opposite from the blue light emitting sections  30 B and red light emitting sections  30 R is called a “lower” side of the axis-Z direction. 
     The base  10  is a substrate primarily formed, for example, of a silicon (Si) substrate, a gallium nitride (GaN) substrate, or a sapphire substrate. A reflection layer is formed on the surface of the base  10 , and the reflection layer is, for example, a laminate in which AlGaN layers and GaN layers are alternately laminated on each other or a laminate in which AlInN layers and GaN layers are alternately laminated on each other. The reflection layer reflects light generated by light emitting layers of the blue light emitting section  30 B and the red light emitting section  30 R, which will be described later, toward the side opposite from the base  10 . 
     The semiconductor layer  11  is provided on the base  10 . The semiconductor layer  11  is formed, for example, of an n-type GaN layer, specifically, a GaN layer to which Si has been doped. 
     The plurality of light emitting sections  30  shown in  FIG. 2  are provided in the form of islands on the base  10  via the semiconductor layer  11 . Light emitting sections  30  adjacent to each other are electrically isolated from each other by a device isolation layer (not shown) provided around the semiconductor layer  11 . The device isolation layer is formed, for example, of an i-type GaN layer, a silicon oxide layer, or a silicon nitride layer. The light emitting sections  30  are formed in the form of islands in a patterning process using etching. That is, the blue light emitting sections  30 B and the red light emitting sections  30 R are electrically isolated from each other. 
     The blue light emitting sections  30 B each include a plurality of nanocolumns (first columnar section)  31  and a light propagation layer  36 . The nanocolumns  31  are each a columnar crystal structure that protrudes and extends upward from the semiconductor layer  11 . The nanocolumns  31  each have, for example, a polygonal, circular, or elliptical planar shape. In the present embodiment, the nanocolumns  31  each have a circular planar shape, as shown in  FIG. 2 . The nanocolumns  31  have a diameter in the order of nanometers, for example, greater than or equal to 10 nm but smaller than or equal to 500 nm. The dimension of the nanocolumns  31  in the lamination direction, what is called a height of the nanocolumns  31 , is, for example, greater than or equal to 0.1 μm but smaller than or equal to 5 μm. 
     In a case where the nanocolumns  31  each have a circular planar shape, the term “the diameter of the nanocolumns  31 ” refers to the diameter of the circular shape, and when the nanocolumns  31  each have a non-circular planar shape, the term refers to the diameter of the minimum circle containing the non-circular shape therein. For example, when the nanocolumns  31  each have a polygonal planar shape, the diameter of the nanocolumns  31  is the diameter of the minimum circle containing the polygonal shape therein, and when the nanocolumns  31  each have an elliptical planar shape, the diameter of the nanocolumns  31  is the diameter of the minimum circle containing the elliptical shape therein. 
     In the case where the nanocolumns  31  each have a circular planar shape, the term “the center of each of the nanocolumns  31 ” refers to the center of the circular shape, and when the nanocolumns  31  each have a non-circular planar shape, the term refers to the center of the minimum circle containing the non-circular shape therein. For example, when the nanocolumns  31  each have a polygonal planar shape, the center of each of the nanocolumns  31  is the center of the minimum circle containing the polygonal shape therein, and when the nanocolumns  31  each have an elliptical planar shape, the center of each of the nanocolumns  31  is the center of the minimum circle containing the elliptical shape therein. 
     The plurality of columnar sections  31  are arranged in a predetermined direction at predetermined intervals in the plan view. The nanocolumns  31  can provide a photonic crystal effect and each trap the light emitted by the light emitting layer in the in-plane direction of the base  10  and output the light in the lamination direction. The “lamination direction” is the direction along the direction of a normal to a surface of the base  10  that is the surface on which the laminate is provided, that is, the substrate surface. The “in-plane direction of the base  10 ” is the direction along a plane perpendicular to the lamination direction. 
     The nanocolumns  31  each have a first semiconductor layer  32 , the light emitting layer (first light emitting layer)  33 , and a second semiconductor layer  34 , as shown in  FIG. 3 . The layers that form each of the nanocolumns  31  are formed by epitaxial growth, as will be described later. 
     The first semiconductor layer  32  is provided on the semiconductor layer  11 . The first semiconductor layer  32  is provided between the base  10  and the light emitting layer  33 . The first semiconductor layer  32  is formed, for example, of an n-type GaN layer to which Si has been doped. In the present embodiment, the first semiconductor layer  32  is made of the same material as that of the semiconductor layer  11 . 
     The light emitting layer  33  is provided on the first semiconductor layer  32 . The light emitting layer  33  is provided between the first semiconductor layer  32  and the second semiconductor layer  34 . The light emitting layer  33  has, for example, a quantum well structure formed of a GaN layer and an InGaN layer. The light emitting layer  33  emits light when electric current is injected thereinto via the first semiconductor layer  32  and the second semiconductor layer  34 . The numbers of GaN layers and InGaN layers that form the light emitting layer  33  are each not limited to a specific number. 
     In the present embodiment, the light emitting layer emits, for example, blue light that belongs to a blue wavelength band from 430 to 470 nm. 
     The second semiconductor layer  34  is provided on the light emitting layer  33 . The second semiconductor layer  34  differs from the first semiconductor layer  32  in terms of conductivity type. The second semiconductor layer  34  is formed, for example, of a p-type GaN layer to which Mg has been doped. The first semiconductor layer  32  and the second semiconductor layer  34  function as a cladding layer having the function of confining the light within the light emitting layer  33 . 
     The light propagation layer  36  is provided so as to surround each of the nanocolumns  31  in the plan view. The refractive index of the light propagation layer  36  is smaller than the refractive index of the light emitting layer  33 . The light propagation layer  36  is, for example, a GaN layer or a titanium oxide (TiO 2 ) layer. The GaN layer, which forms the light propagation layer  36 , can be of i-type, n-type, or p-type. The light propagation layer  36  allows the light generated in the light emitting layer  33  to propagate in the in-plane direction. 
     In the blue light emitting section  30 B, the laminate of the p-type second semiconductor layer  34 , the light emitting layer  33 , to which no impurity has been doped, and the n-type first semiconductor layer  32  forms a pin diode. The bandgap of each of the first semiconductor layer  32  and the second semiconductor layer  34  is wider than the bandgap of the light emitting layer  33 . In the blue light emitting section  30 B, when the forward bias voltage for the pin diode is applied to the space between the lower-layer electrode  60 B and the upper-layer electrode  70 B so that current is injected into the pin diode, electrons and holes recombine with each other in the light emitting layer  33 . The recombination causes light emission. 
     The first semiconductor layer  32  and the second semiconductor layer  34  cause the light generated in the light emitting layer  33  to propagate through the light propagation layer  36  in the in-plane direction of the base  10 . In this process, the photonic crystal effect provided by the nanocolumns  31  causes the light to form a standing wave, which is confined in the in-plane direction of the base  10 . The confined light receives gain in the light emitting layer  33  and undergoes laser oscillation. That is, the nanocolumns  31  cause the light generated in the light emitting layer  33  to resonate in the in-plane direction of the base  10 , resulting in laser oscillation. Specifically, the light generated in the light emitting layer  33  resonates in the in-plane direction of the base  10  in a resonant section formed by the plurality of nanocolumns  31 , resulting in laser oscillation. The positive first-order diffracted light and the negative first-order diffracted light generated by the resonance then travel as laser light in the lamination direction (axis-Z direction). 
     In the light emitting device  20 , the refractive indices and thicknesses of the first semiconductor layers  32 , the second semiconductor layers  34 , and the light emitting layers  33  are so designed that the intensity of the light propagating in the in-plane direction is maximized in the light emitting layers  33  in the axis-Z direction. 
     In the present embodiment, out of the laser light that travels in the lamination direction, the laser light that travels toward the base  10  is reflected off a reflection layer (not shown) formed on the surface of the base  10  and travels upward. The blue light emitting sections  30 B can thus emit the light via the upper side. 
     An insulating layer  35  is provided on the semiconductor layer  11  as shown in  FIG. 3 . The insulating layer  35  is provided between the light propagation layer  36  and the semiconductor layer  11 . The insulating layer  35  functions as a mask for growing the films that form the nanocolumns  31  in the step of manufacturing the blue light emitting sections  30 B. The insulating layer  35  is formed, for example, of a silicon oxide layer or a silicon nitride layer. 
     The first protective layer  51  is provided on the base  10  (semiconductor layer  11 ) so as to cover the blue light emitting sections  30 B. The first protective layer  51  is, for example, a silicon oxide layer. The first protective layer  51  has the function of planarizing the upper surface of the base  10  and protecting the blue light emitting sections  30 B from impact and other external influences. The first protective layer  51  has contact holes (first through hole)  151 , which expose the upper side of the blue light emitting sections  30 B. 
     The lower-layer electrode  60 B is provided on the semiconductor layer  11  on the side facing the blue light emitting sections  30 B. The lower-layer electrode  60 B is electrically coupled to the first semiconductor layers  32  of the nanocolumns  31  via the semiconductor layer  11 . The lower-layer electrode  60 B is one of the electrodes for injecting the current into the light emitting layers  33 . The lower-layer electrode  60 B is formed, for example, of a metal layer made, for example, of Ni, Ti, Cr, Pt, or Au or a laminated metal film formed of layers made of the elements described above. 
     The upper-layer electrode  70 B is provided on the blue light emitting sections  30 B. The upper-layer electrode  70 B is the other one of the electrodes for injecting the current into the light emitting layers  33  of the nanocolumns  31 . The upper-layer electrode  70 B is provided so as to be in contact with part of the nanocolumns  31  and the light propagation layer  36 . The upper-layer electrode  70 B is formed of a plurality of upper-layer electrodes  70 B in accordance with the number of blue light emitting sections  30 B. Part of each of the upper-layer electrodes  70 B is exposed in the contact hole  151  provided in the first protective layer  51 . 
     The upper-layer electrodes  70 B are each formed, for example, of a metal layer made, for example, of Ni, Ti, Cr, Pt, or Au or a laminated metal film formed of layers made of some of the elements described above. The upper-layer electrodes  70 B are electrodes for improving the conductivity between the drawn electrode  71 B and the blue light emitting sections  30 B. The upper-layer electrodes  70 B are each a thin film having a thickness of about several tens of nanometers and therefore transmit light. 
     The drawn electrode  71 B is coupled to the upper-layer electrodes  70 B, which are exposed in the contact holes  151 . The drawn electrode  71 B is drawn over the first protective layer  51  via the contact holes  151 . 
     The drawn electrode  71 B is a light transmissive, electrically conductive layer formed, for example, of an ITO (indium tin oxide) layer or an IZO (indium zinc oxide) layer. The light generated in the light emitting layers  33  passes through the upper-layer electrodes  70 B and the drawn electrode  71 B and exits upward. 
     The first wiring  81  is laminated on the drawn electrode  71 B. The first wiring  81  is electrically coupled to the second semiconductor layers  34  in the nanocolumns  31  in the blue light emitting sections  30 B via the drawn electrode  71 B and the upper-layer electrodes  70 B. The first wiring  81  is formed, for example, of a metal layer made, for example, of Ni, Ti, Cr, Pt, or Au or a laminated metal film formed of layers made of some of the elements described above. 
     The first wiring  81  is coupled, for example, via wires to a drive circuit provided on the base  10  in a region that is not shown. The lower-layer electrode  60 B described above is coupled, for example, via wires to the drive circuit provided on the base  10  in the region that is not shown. Based on the configuration described above, the light emitting apparatus  12  injects current into the light emitting layers via the lower-layer electrode  60 B and the upper-layer electrodes  70 B by driving the drive circuit, and the blue light emitting sections  30 B can thus emit light. 
     On the other hand, the red light emitting sections  30 R each include a plurality of nanocolumns (second columnar section)  41  and a light propagation layer  46 . The red light emitting sections  30 R each have the same configuration as that of each of the blue light emitting sections  30 B except that the color of the light emitted by the red light emitting section  30 R differs from the color of the light emitted by the blue light emitting section  30 B. The same configurations of each of the red light emitting sections  30 R as those of each of the blue light emitting section  30 B will not therefore be described below. 
     The nanocolumns  41  each include a light emitting layer (second light emitting layer)  43 , which emits red light, as shown in  FIG. 3 . 
     The second protective layer  52  is provided on the base  10  (semiconductor layer  11 ) so as to cover the red light emitting sections  30 R. The second protective layer  52  is made of the same material as that of the first protective layer  51 . The second protective layer  52  has the function of planarizing the upper surface of the base  10  and protecting the red light emitting sections  30 R from impact and other external influences. The second protective layer  52  has contact holes (second through hole)  152 , which expose the upper side of the red light emitting sections  30 R. 
     The lower-layer electrode  60 R is provided on the semiconductor layer  11  on the side facing the red light emitting sections  30 R. The lower-layer electrode  60 R is one of the electrodes for injecting current into light emitting layers  43  of the nanocolumns  41 . The upper-layer electrode  70 R is provided on the red light emitting sections  30 R. The upper-layer electrode  70 R is the other one of the electrodes for injecting the current into the light emitting layers  43  of the nanocolumns  41 . The upper-layer electrode  70 R is provided so as to be in contact with part of the nanocolumns and the light propagation layer  46 . The upper-layer electrode  70 R is formed of a plurality of upper-layer electrodes  70 R in accordance with the number of red light emitting sections  30 R. Part of each of the upper-layer electrodes  70 R is exposed in the contact hole  152  provided in the second protective layer  52 . 
     The drawn electrode  71 R is coupled to the upper-layer electrodes  70 R, which are exposed in the contact holes  152 . The drawn electrode  71 R is drawn over the second protective layer  52  via the contact holes  152 . 
     The second wiring  82  is laminated on the drawn electrode  71 R. The second wiring  82  is electrically coupled to the nanocolumns  41  in the red light emitting sections  30 R via the drawn electrode  71 R and the upper-layer electrodes  70 R. 
     The second wiring  82  is coupled, for example, via wires, to a drive circuit provided on the base  10  in a region that is not shown. The lower-layer electrode  60 R described above is coupled, for example, via wires, to the drive circuit on the base  10  in the region that is not shown. Based on the configuration described above, the light emitting device  20  injects current into the light emitting layers  43  via the lower-layer electrode  60 R and the upper-layer electrodes  70 R by driving the drive circuit, and the red light emitting sections  30 R can thus emit light. 
     In the light emitting apparatus  12  according to the present embodiment, the light emitting area of each of the blue light emitting sections  30 B is configured to be greater than that of each of the red light emitting sections  30 R in the light emitting device  20 , as described above. The size of the light emitting area is defined by the area where the nanocolumns are in contact with the electrodes, that is, the size of the electrodes formed on the nanocolumns. That is, in the present embodiment, the area of the upper-layer electrode  70 B formed on the nanocolumns  31  in each of the blue light emitting sections  30 B is greater than the area of the upper-layer electrode  70 R formed on the nanocolumns  41  in each of the red light emitting sections  30 R. The diameter of the opening of the contact holes  151 , which expose the upper-layer electrodes  70 B, is therefore greater than the diameter of the opening of the contact holes  152 , which expose the upper-layer electrodes  70 R. 
     The contact holes  151  each include an upper hole (first hole)  1511  and a lower hole (second hole)  1512 , as shown in  FIG. 3 . The lower hole  1512  is located in a position shifted from the upper hole  1511  toward the base  10  (lower side), and the upper hole  1511  is located above the lower hole  1512  (on the side opposite from base  10 ). 
     In the present embodiment, the contact holes  151  are formed in an etching step, as will be described later. The contact holes  151 , specifically, the upper holes  1511  and the lower holes  1512  are formed in a two-stage etching step. The etching conditions under which the upper holes  1511  are formed in the first protective layer  51  differ from the etching conditions under which the lower holes  1512  are formed in the first protective layer  51 . The step of etching the contact holes  151  will be described later. 
     In the present embodiment, the upper holes  1511  are each so tapered that the inner diameter thereof narrows downward. The upper hole  1511  is therefore so shaped that a first opening  1511   a , which is the upper-end opening and is located in a position farthest (uppermost) from the base  10 , has a first opening area S 1 , which is the largest area, and a fifth opening  1511   b , which is the lower-end opening and is located in a position closest to the base  10 , has a fifth opening area S 5 , which is the smallest area. 
     The lower holes  1512  are each formed in part of a bottom surface  1513  of the upper hole  1511 . The lower hole  1512  exposes part of the upper-layer electrode  70 B. The bottom surface  1513  of the upper hole  1511  is a flat surface. Since the upper hole  1511  is formed in an etching step, as will be described later, the state in which the bottom surface  1513  is a flat surface means that the bottom surface is not a flat surface with no irregularities, such as a mirror surface, but is a surface having minute irregularities that can be typically produced in an etching step. 
     In the present embodiment, the lower hole  1512  is so tapered that the inner diameter thereof narrows downward. The lower hole  1512  is therefore so shaped that the upper-end opening, which is located in a position farthest (uppermost) from the base  10 , has a largest opening area and a second opening  1512   a , which is the lower-end opening and is located in a position closest to the base  10 , has a second opening area S 2 , which is the smallest area. The opening area of the upper-end opening of the lower hole  1512  is smaller than the fifth opening area S 5  of the upper hole  1511 . 
     In the present embodiment, the first opening area S 1  of the upper hole  1511  is greater than the second opening area S 2  of the lower hole  1512 . 
     In the present embodiment, the thickness of the first protective layer  51 , which covers the upper-layer electrodes  70 B, is set at a value ranging, for example, from 600 to 1000 nm. 
     The upper hole  1511  is so formed that the thickness of a portion of the first protective layer  51  that is the portion (bottom surface  1513 ) that covers the upper-layer electrode  70 B is about ¼ to ⅙ of the thickness of the first protective layer  51 . It is desirable to ensure that the portion that covers the upper-layer electrode  70 B has a thickness of 150 nm or greater in consideration of current leakage and other factors. 
     For example, when the first protective layer  51  that covers the upper-layer electrode  70 B has a thickness of 600 nm, the depth of the upper hole  1511  may be set at 450 nm to allow the first protective layer  51  having the film thickness of 150 nm to cover the upper-layer electrode  70 B. When the first protective layer  51  that covers the upper-layer electrode  70 B has a thickness of 1000 nm, the depth of the upper hole  1511  may be set at 850 nm to allow the first protective layer  51  having the film thickness of 150 nm to cover the upper-layer electrode  70 B. 
     The contact holes  152  each include an upper hole (third hole)  1521  and a lower hole (fourth hole)  1522 , as shown in  FIG. 3 . The lower hole  1522  is located in a position shifted from the upper hole  1521  toward the base  10  (lower side), and the upper hole  1521  is located above the lower hole  1522 . 
     In the present embodiment, the contact holes  152  are formed in an etching step, as will be described later. The contact holes  152 , specifically, the upper holes  1521  and the lower holes  1522  are formed in a two-stage etching step. That is, the etching conditions under which the upper holes  1521  are formed in the second protective layer  52  differ from the etching conditions under which the lower holes  1522  are formed in the second protective layer  52 . The upper holes  1521  are formed in the same etching step as the etching step in which the upper holes  1511  of the contact holes  151  are formed. The lower holes  1522  are formed in the same etching step as the etching step in which the lower holes  1512  of the contact holes  151  are formed. The step of etching the contact holes  152  will be described later. 
     In the present embodiment, the upper holes  1521  are each so tapered that the inner diameter thereof narrows downward. The upper hole  1521  is therefore so shaped that a third opening  1521   a , which is the upper-end opening and is located in a position farthest (uppermost) from the base  10 , has a third opening area S 3 , which is the largest area, and a sixth opening  1521   b , which is the lower-end opening and is located in a position closest to the base  10 , has a sixth opening area S 6 , which is the smallest area. 
     The lower holes  1522  are each formed in part of a bottom surface  1523  of the upper hole  1521 . The lower hole  1522  exposes part of the upper-layer electrode  70 R. The bottom surface  1523  of the upper hole  1521  is a flat surface. The state in which the bottom surface  1523  is a flat surface means that the bottom surface is a surface having minute irregularities that can be typically produced in an etching step. 
     In the present embodiment, the lower hole  1522  is so tapered that the inner diameter thereof narrows downward. The lower hole  1522  is therefore so shaped that an upper-end opening that is located in a position farthest (uppermost) from the base  10  has a largest opening area and a fourth opening  1522   a , which is the lower-end opening and is located in a position closest to the base  10 , has a fourth opening area S 4 , which is the smallest area. The opening area of the upper-end opening of the lower hole  1522  is smaller than the sixth opening area S 6  of the upper hole  1521 . 
     In the present embodiment, the third opening area S 3  of the upper hole  1521  is greater than the fourth opening area S 4  of the lower hole  1522 . 
     In the present embodiment, the first opening area S 1  of the upper hole  1511  of each of the contact holes  151  is equal to the third opening area S 3  of the upper hole  1521  of each of the contact holes  152 . The fifth opening area S 5  of the upper hole  1511  of each of the contact holes  151  is equal to the sixth opening area S 6  of the upper hole  1521  of each of the contact holes  152 . 
     As described above, in the present embodiment, the upper holes  1511  of the contact holes  151  and the upper holes  1521  of the contact holes  152  have the same opening shape. The upper holes  1511  and the upper holes  1521  are holes having been etched at the same etching rate. 
     On the other hand, in the present embodiment, the lower holes  1512  of the contact holes  151  and the lower holes  1522  of the contact holes  152  have different opening shapes. The lower holes  1512  and the lower holes  1522  are holes having been etched at different etching rates. 
     In the present embodiment, the second opening area S 2  of the lower holes  1512  of the contact holes  151  is greater than the fourth opening area S 4  of the lower holes  1522  of the contact holes  152 . The contact holes  151  can thus expose the upper-layer electrodes  70 B, which each have an area larger than that of each of the upper-layer electrodes  70 R. 
     A first area ratio is now defined as the ratio between the first opening area S 1  of the upper hole  1511  of each of the contact holes  151  and the third opening area S 3  of the upper hole  1521  of each of the contact holes  152 . A second area ratio is defined as the ratio between the second opening area S 2  of the lower hole  1512  of each of the contact holes  151  and the fourth opening area S 4  of the lower hole  1522  of each of the contact holes  152 . 
     Since the upper holes  1511  and  1521  have the same opening shape as described above, the first area ratio is about 1. Since the second opening area S 2  is greater than the fourth opening area S 4  as described above, the second area ratio is smaller than 1. For example, when the second opening area S 2  is twice as large as the fourth opening area S 4 , the second area ratio is 0.5. 
     As described above, in the light emitting apparatus  12  according to the present embodiment, the first area ratio, which is the ratio between the first opening area S 1  and the third opening area S 3 , is smaller than the second area ratio, which is the ratio between the second opening area S 2  and the fourth opening area S 4 . 
     The contact holes  151  are formed in positions where the contact holes  151  expose part of the upper-layer electrodes  70 B in the plan view viewed in the direction of a normal to the substrate that forms the base  10 . That is, the contact holes  151  are each so formed that an outer edge  512  of the second opening  1512   a  of the lower hole  1512  of the contact hole  151  overlaps with the upper-layer electrode  70 B in the plan view viewed in the direction of a normal to the base  10 . The outer edge  512  of the second opening  1512   a  may at least partially overlap with the upper-layer electrode  70 B. 
     The contact holes  152  are formed in positions where the contact holes  152  expose part of the upper-layer electrodes  70 R in the plan view viewed in the direction of a normal to the substrate that forms the base  10 . That is, the contact holes  152  are each so formed that an outer edge  522  of the fourth opening  1522   a  of the lower hole  1522  of the contact hole  152  overlaps with the upper-layer electrode  70 R in the plan view viewed in the direction of a normal to the base  10 . The outer edge  522  of the fourth opening  1522   a  may at least partially overlap with the upper-layer electrode  70 R. 
     A method for manufacturing the light emitting apparatus  12  according to the present embodiment will be subsequently described. 
       FIGS. 4A to 4E  show key parts in the steps of manufacturing the light emitting apparatus  12 . The following description will be primarily made of the steps of manufacturing the blue light emitting sections  30 B and the red light emitting sections  30 R. 
     First, the step of forming the light emitting sections  30 , which each include the blue light emitting section  30 B and the red light emitting section  30 R, in the form of islands on the base  10  is carried out, as shown in  FIG. 4A . 
     In the step of forming the light emitting sections  30 , the semiconductor layer  11  is first epitaxially grown in a predetermined region on the base  10 . Examples of the epitaxial growth method may include the MOCVD (metal organic chemical vapor deposition) method and the MBE (molecular beam epitaxy) method. 
     First, a plurality of nanocolumns  31  are formed on the semiconductor layer  11 , and the optical propagation layer  36  is formed around each of the nanocolumns  31 . 
     Specifically, to form the nanocolumns  31 , the insulating layer  35  is formed on the semiconductor layer  11 . The insulating layer  35  is formed, for example, by deposition using the CVD (chemical vapor deposition) or the sputtering method and patterning using photolithography and etching (hereinafter also simply referred to as “patterning”). The insulating layer  35  with openings formed therein can be used as a mask to form the nanocolumns  31  by epitaxially growing the first semiconductor layers  32 , the light emitting layers  33 , and the second semiconductor layers  34  in this order on the semiconductor layer  11 , for example, by using the MOCVD method or the MBE method. 
     The light propagation layer  36  is formed around each of the nanocolumns  31  after the nanocolumns  31  are formed. The light propagation layer  36  is formed, for example, by using an ELO (epitaxial lateral overgrowth) method using the MOCVD or MBE method. 
     Thereafter, unnecessary nanocolumns  31  and light propagation layer  36  formed in the region excluding the regions where the blue light emitting sections  30 B are to be formed are removed, for example, in a dry etching process using a Cl-based etching gas. The blue light emitting sections  30 B are thus formed on the semiconductor layer  11 . 
     The upper-layer electrodes  70 B are then formed on the blue light emitting sections  30 B. The blue light emitting sections  30 B are formed, for example, by film formation using sputtering or vacuum evaporation, and patterning. 
     To form the red light emitting sections  30 R, a plurality of nanocolumns  41  are formed on the semiconductor layer  11 , and the light propagation layer  46  is formed around each of the nanocolumns  41 , followed by dry-etching-based removal of unnecessary nanocolumns  41  and light propagation layer  46  formed in the region excluding the regions where the red light emitting sections  30 R are to be formed, as in the formation of the blue light emitting sections  30 B. The red light emitting sections  30 R are thus formed on the semiconductor layer  11 . The upper-layer electrodes  70 R are then formed on the red light emitting sections  30 R. In the present embodiment, the area of each of the upper-layer electrodes  70 R is smaller than the area of each of the upper-layer electrodes  70 B. 
     Subsequently, the first protective layer  51  is formed on the base  10  so as to cover the blue light emitting sections  30 B and the upper-layer electrode  70 B, as shown in  FIG. 4B . The second protective layer  52  is formed on the base  10  so as to cover the red light emitting sections  30 R and the upper-layer electrodes  70 R. The first protective layer  51  and the second protective layer  52  are formed, for example, by film formation using spin coating. The first protective layer  51  and the second protective layer  52  are therefore made of the same material. 
     Subsequently, the contact holes  151  and  152  are formed in the first protective layer  51  and the second protective layer  52 , respectively. Although not shown in the figures, the first protective layer  51  and the second protective layer  52  are each patterned into a predetermined shape before the formation of the contact holes  151  and  152 . 
     Specifically, the upper holes  1511  as the first hole are formed in first positions P 1  in the first protective layer  51 , where the upper holes  1511  overlap with the upper-layer electrodes  70 B, as shown in  FIG. 4C . In the present embodiment, in the formation of the upper holes  1511  in the first protective layer  51 , the upper holes (first hole)  1521  are simultaneously formed in second positions P 2  in the second protective layer  52 , where the upper holes  1521  overlap with the upper-layer electrodes  70 R. Since the upper holes  1511  and  1521  have the same opening shape, the upper holes  1511  and  1521  are formed under the same etching conditions. 
     Subsequently, the lower holes  1512  as the second hole each having an opening area smaller than the opening area of each of the upper holes  1511  are formed in the bottom surfaces  1513  of the upper holes  1511  formed in the first positions P 1 , so that the contact holes  151 , which expose part of the upper-layer electrodes  70 B, are formed, as shown in  FIG. 4D . The lower holes  1522  as the third hole each having an opening area smaller than the opening area of each of the lower holes  1512  are formed in the bottom surfaces  1523  of the upper holes  1521  formed in the second positions P 2 , so that the contact holes  152 , which expose part of the upper-layer electrodes  70 R, are formed. 
     In general, it is difficult to use the same etching rate to form holes having different opening areas. For example, the step of etching a hole having a large opening area uses a large amount of etching gas, so that the etching period is shorter than that for a hole having a small opening area. Therefore, to etch large-diameter and small-diameter holes at the same time, the etching period set at a value suitable for the large-diameter hole, the etching of which relatively readily progresses, is not long enough for the small-diameter hole, the etching of which does not relatively readily progress, so that the small-diameter hole is not etched sufficiently, resulting in a problem of poor conductivity and other problems due to adhesion of etching residues. 
     On the other hand, when the etching period is set at a value suitable for the small-diameter hole, the etching of which does not relatively readily progress, the etching period for which the large-diameter hole is etched increases, so that the electrode exposed through the large-diameter hole is exposed to the plasma for a long period, resulting in a problem of degradation of the characteristics of the final product due to the etching damage. 
     In contrast, in the present embodiment, forming the upper holes  1511  and  1521  in the first protective layer  51  and the second protective layer  52  in advance reduces the thickness of the first protective layer  51  that covers the upper-layer electrodes  70 B and the thickness of the second protective layer  52  that covers the upper-layer electrodes  70 R. The thicknesses of the layers to be etched to form the lower holes  1512  and  1522  can thus be reduced by the depths of the upper holes  1511  and  1521  as compared with a case where the lower holes  1512  and  1522  are formed directly in the first protective layer  51  and the second protective layer  52  without formation of the upper holes  1511  and  1512 . Therefore, even when the contact holes  151  and  152  having different opening diameters are formed in the first protective layer  51  and the second protective layer  52 , occurrence of problems, such as degradation of the characteristics of the final product due to etching residues and etching damage caused by a difference in etching rate can be suppressed. 
     Subsequently, the drawn electrode  71 B is formed on the upper-layer electrodes  70 B exposed in the contact holes  151 , and the drawn electrode  71 R is formed on the upper-layer electrodes  70 R exposed in the contact holes  152 , as shown in  FIG. 4E . The drawn electrodes  71 B and  71 R are formed, for example, by film formation using sputtering or vacuum evaporation, and patterning. Subsequently, the first wiring  81  and the second wiring  82  are formed on the drawn electrodes  71 B and  71 R, respectively. The first wiring  81  and the second wiring  82  are formed, for example, by film formation using sputtering or vacuum evaporation, and patterning. 
     The lower-layer electrodes  60 B and  60 R (see  FIG. 3 ) are then formed in regions that are not shown and differ from the regions where the light emitting sections  30  are formed. The lower-layer electrodes  60 B and  60 R are formed, for example, by film formation using sputtering or vacuum evaporation, and patterning. The step of forming the lower-layer electrodes  60 B and  60 R and the step of forming the drawn electrodes  71 B and  71 R and the first wiring  81  and the second wiring  82  are not necessarily carried out in a specific order. 
     Finally, the drive circuits are mounted on the base  10 , for example, by using bonding members (not shown), and the drive circuits are electrically coupled to the lower-layer electrodes  60 B and  60 R, the first wiring  81 , and the second wiring  82  of the light emitting sections  30 , for example, with wires. The heat sink  21  is then attached to the lower surface (surface facing side −Z) of the base  10 . The light emitting apparatus  12  according to the present embodiment is thus manufactured. 
     Effects of Present Embodiment 
     As described above, the light emitting apparatus  12  according to the present embodiment includes the base  10 , the blue light emitting sections  30 B provided on the base  10 , the red light emitting sections  30 R provided on the base  10 , the upper-layer electrodes  70 B provided on one side of the blue light emitting sections  30 B that is the side opposite from the base  10 , the upper-layer electrodes  70 R provided on one side of the red light emitting sections  30 R that is the side opposite from the base  10 , the first protective layer  51 , which covers the blue light emitting sections  30 B and the upper-layer electrodes  70 B, and the second protective layer  52 , which covers the red light emitting sections  30 R and the upper-layer electrodes  70 R. The area of each of the upper-layer electrodes  70 B is greater than the area of each of the upper-layer electrodes  70 R. The first protective layer  51  has the contact holes  151 , which expose part of the upper-layer electrodes  70 B. The second protective layer  52  has the contact holes  152 , which expose part of the upper-layer electrodes  70 R. The contact holes  151  each have the upper hole  1511  and the lower hole  1512 , which is located in a position shifted from the upper hole  1511  toward the base  10 . The contact holes  152  each have the upper hole  1521  and the lower hole  1522 , which is located in a position shifted from the upper hole  1521  toward the base  10 . The first opening area S 1  of an opening of the upper hole  1511  that is the opening farthest from the base  10  is greater than the second opening area S 2  of an opening of the lower hole  1512  that is the opening closest to the base  10 . The third opening area S 3  of an opening of the upper hole  1521  that is the opening farthest from the base  10  is greater than the fourth opening area S 4  of an opening of the lower hole  1522  that is the opening closest to the base  10 . The second opening area S 2  is greater than the fourth opening area S 4 . 
     In the light emitting apparatus  12  according to the present embodiment, part of the upper-layer electrodes  70 B is exposed through the contact holes  151  each having the upper hole  1511  and the lower hole  1512 , and part of the upper-layer electrodes  70 R is exposed through the contact holes  152  each having the upper hole  1521  and the lower hole  1522 . Forming the upper holes  1511  and  1521  in the first protective layer  51  and the second protective layer  52  therefore reduces the thickness of the first protective layer  51  that covers the upper-layer electrodes  70 B, and the thickness of the second protective layer  52  that covers the upper-layer electrodes  70 R. The thicknesses of the layers to be etched to form the lower holes  1512  and  1522  having different diameters can thus be reduced as compared with the configuration in which the lower holes  1512  and  1522  are formed directly in the first protective layer  51  and the second protective layer  52 . 
     Therefore, when the contact holes  151  and  152  having different opening diameters are formed in the first protective layer  51  and the second protective layer  52 , degradation of the characteristics of the final product due to etching residues and etching damage caused by a difference in etching rate can be suppressed. The light emitting apparatus  12  according to the present embodiment is therefore highly reliable with the degree of the problem caused by a difference in etching rate lowered. 
     In the light emitting apparatus  12  according to the present embodiment, the first area ratio, which is the ratio between the first opening area S 1  and the third opening area S 3 , is smaller than the second area ratio, which is the ratio between the second opening area S 2  and the fourth opening area S 4 . 
     According to the configuration described above, the upper hole  1511  of each of the contact holes  151  and the upper hole  1521  of each of the contact holes  152  can be brought closer to each other in terms of the opening shape. The steps of etching the upper holes  1511  and  1521  can thus be carried out in a single step, whereby the upper holes  1511  and  1521  are readily manufactured. 
     In the light emitting apparatus  12  according to the present embodiment, the first opening area S 1  is equal to the third opening area S 3 , and the fifth opening area S 5 , which is the area of an opening of the upper hole  1511  that is the opening closest to the base  10 , is equal to the sixth opening area S 6 , which is the area of an opening of the upper hole  1521  that is the opening closest to the base  10 . 
     According to the configuration described above, the openings of the upper holes  1511  and  1521  have the same shape, whereby the contact holes are readily formed. 
     In the light emitting apparatus  12  according to the present embodiment, the lower holes  1512  are formed in part of the bottom surfaces  1513  of the upper holes  1511 , and the lower holes  1522  are formed in part of the bottom surfaces  1523  of the upper holes  1521 . 
     According to the configuration described above, after the formation of the upper holes  1511  and  1521  in a first etching step, the lower holes  1512  and  1522  can be formed in a second etching step. The contact holes  151  and  152  can thus be formed in the two-stage etching step, whereby the degree of the problem caused by a difference in etching rate can be lowered. 
     In the light emitting apparatus  12  according to the present embodiment, the bottom surface  1513  of each of the upper holes  1511  and the bottom surface  1523  of each of the upper holes  1521  are each a flat surface. 
     According to the configuration described above, the depths of the upper holes  1511  and  1521  are readily controlled, whereby the upper holes  1511  and  1521  are readily manufactured. 
     In the light emitting apparatus  12  according to the present embodiment, the blue light emitting sections  30 B each include a plurality of nanocolumns  31  each including the light emitting layer  33 , and the red light emitting sections  30 R each include a plurality of nanocolumns  41  each including the light emitting layer  43 . 
     In this case, the light emitting apparatus  12  having a structure including the plurality of nanocolumns  31  and  41  as the blue light emitting sections  30 B and the red light emitting sections  30 R can be provided. 
     The method for manufacturing the light emitting apparatus  12  according to the present embodiment includes forming the blue light emitting sections  30 B and the red light emitting sections  30 R on the base  10 , forming the upper-layer electrodes  70 B on one side of the blue light emitting sections  30 B that is the side opposite from the base  10 , forming the upper-layer electrodes  70 R, which each have an area smaller than the area of each of the upper-layer electrodes  70 B, on one side of the red light emitting sections  30 R that is the side opposite from the base  10 , forming the first protective layer  51  on the base  10  so as to cover the blue light emitting sections  30 B and the upper-layer electrodes  70 B, forming the second protective layer  52  on the base  10  so as to cover the red light emitting sections  30 R and the upper-layer electrodes  70 R, forming the upper holes  1511  in the first positions P 1  in the first protective layer  51 , where the upper holes  1511  overlap with the upper-layer electrodes  70 B, and the upper holes  1521  in the second positions P 2  in the second protective layer  52 , where the upper holes  1521  overlap with the upper-layer electrodes  70 R, forming the lower holes  1512  in the bottom surfaces  1513  of the upper holes  1511  formed in the first positions P 1 , the lower holes  1512  each having an opening area smaller than the opening area of each of the upper holes  1511 , to form the contact holes  151 , which expose part of the upper-layer electrodes  70 B, and forming the lower holes  1522  in the bottom surfaces  1523  of the upper holes  1521  formed in the second positions P 2 , the lower holes  1522  each having an opening area smaller than the opening area of each of the lower holes  1512 , to form the contact holes  152 , which expose part of the upper-layer electrodes  70 R. 
     The method for manufacturing the light emitting apparatus  12  according to the present embodiment, which forms the upper holes  1511  and  1521  in the first protective layer and the second protective layer  52  in advance, allows reduction in the thickness of the first protective layer  51  that covers the upper-layer electrodes  70 B and the thickness of the second protective layer  52  that covers the upper-layer electrodes  70 R. The thicknesses of the protective layers to be etched to form the lower holes  1512  and  1522 , which have different diameters, can therefore be reduced by the depth of the upper holes  1511  and  1521 . 
     The contact holes  151  and  152  having different opening diameters can therefore be formed in the first protective layer  51  and the second protective layer  52  with degradation of the characteristics of the final product and other problems due to etching residues and etching damage caused by a difference in etching rate suppressed. A light emitting apparatus  12  having excellent reliability can therefore be provided. 
     The projector  1  according to the present embodiment includes the light emitting apparatus  12 . 
     According to the present embodiment, providing the light emitting apparatus  12 , which can suppress the problem caused by the etching step, allows the projector  1  to excel in reliability and display bright, high-quality images. 
     The technical scope of the present disclosure is not limited to the embodiment described above, and a variety of changes can be made thereto to the extent that the changes do not depart from the substance of the present disclosure. 
     For example, the aforementioned embodiment has been described with reference to the case where the light emitting sections  30  are each formed of a plurality of nanocolumns by way of example, but the present disclosure is not limited thereto. 
       FIG. 5  is a cross-sectional view showing the configuration of a light emitting device  120  according to a variation. The light emitting device  120  according to the present variation has a configuration in which a light emitting section  130  is a laminate of film-shaped crystal structures, as shown in  FIG. 5 . The light emitting section  130  has a configuration in which a film-shaped first semiconductor layer  132 , a film-shaped light emitting layer  133 , and a film-shaped second semiconductor layer  134  are laminated on each other. In the configuration of the variation, a non-light-transmissive material is used as a protective layer that covers the light emitting section  130 . 
     The aforementioned embodiment has been described with reference to the case where the light emitting layers are made of an InGaN-based material, and the light emitting layers can be made of any of a variety of other semiconductor materials in accordance with the wavelengths of the light to be outputted from the light emitting layers. Examples of the semiconductor material may include an AlGaN-based, AlGaAs-based, InGaAs-based, InGaAsP-based, InP-based, GaP-based, and AlGaP-based semiconductor materials. The diameter of the photonic crystal structures or the intervals at which the photonic crystal structures are arranged may be changed as appropriate in accordance with the wavelengths of the light to be outputted from the light emitting layers. 
     In addition to the above, the specific descriptions of the shape, the number, the arrangement, the material, and other factors of each component of the light emitting apparatus and the projector are not limited to those in the embodiment described above and can be changed as appropriate. 
     The aforementioned embodiment has been described with reference to the case where the light emitting apparatus according to the present disclosure is incorporated in a projector, but not necessarily. For example, the light emitting apparatus according to the present disclosure is applicable to a micro-LED display, a head mounted display, or a display apparatus of a smartwatch. The light emitting apparatus according to the present disclosure can be used in a lighting apparatus, a headlight of an automobile, and other products. 
     A light emitting apparatus according to an aspect of the present disclosure may have the configuration below. 
     The light emitting apparatus according to the aspect of the present disclosure includes a substrate, a first light emitting section provided on the substrate, a second light emitting section provided on the substrate, a first electrode provided on one side of the first light emitting section that is the side opposite from the substrate, a second electrode provided on one side of the second light emitting section that is the side opposite from the substrate, a first protective layer that covers the first light emitting section and the first electrode, and a second protective layer that covers the second light emitting section and the second electrode. The area of the first electrode is greater than the area of the second electrode in the plan view viewed in the direction of a normal to the substrate. The first protective layer has a first through hole. The second protective layer has a second through hole. The first through hole has a first hole and a second hole located in a position shifted from the first hole toward the substrate. The second through hole has a third hole and a fourth hole located in a position shifted from the third hole toward the substrate. A first opening area of a first opening of the first hole, which is the opening farthest from the substrate, is greater than a second opening area of a second opening of the second hole, which is the opening closest to the substrate. A third opening area of a third opening of the third hole, which is the opening farthest from the substrate, is greater than a fourth opening area of a fourth opening of the fourth hole, which is the opening closest to the substrate. In the plan view, the outer edge of the second opening overlaps with the first electrode, and the outer edge of the fourth opening overlaps with the second electrode. The second opening area is greater than the fourth opening area. 
     In the light emitting apparatus according to the aspect of the present disclosure, a first area ratio that is the ratio between the first opening area and the third opening area may be smaller than a second area ratio that is the ratio between the second opening area and the fourth opening area. 
     In the light emitting apparatus according to the aspect of the present disclosure, the first opening area may be equal to the third opening area, and a fifth opening area that is the area of a fifth opening of the first hole that is the opening closest to the substrate may be equal to a sixth opening area that is the area of a sixth opening of the third hole that is the opening closest to the substrate. 
     In the light emitting apparatus according to the aspect of the present disclosure, the second hole may be formed in part of the bottom surface of the first hole, and the fourth hole may be formed in part of the bottom surface of the third hole. 
     In the light emitting apparatus according to the aspect of the present disclosure, the bottom surface of the first hole and the bottom surface of the third hole may be each a flat surface. 
     In the light emitting apparatus according to the aspect of the present disclosure, the first light emitting section may include a plurality of first columnar sections each including a first light emitting layer, and the second light emitting section may include a plurality of second columnar sections each including a second light emitting layer. 
     A method for manufacturing the light emitting apparatus according to another aspect of the present disclosure may have the configurations below. 
     The method for manufacturing the light emitting apparatus according to the other aspect of the present disclosure includes forming a first light emitting section and a second light emitting section on a substrate, forming a first electrode on one side of the first light emitting section that is the side opposite from the substrate, forming a second electrode having an area smaller than the area of the first electrode on one side of the second light emitting section that is the side opposite from the substrate, forming a first protective layer on the substrate so as to cover the first light emitting section and the first electrode, forming a second protective layer on the substrate so as to cover the second light emitting section and the second electrode, forming a first hole in a first position in the first protective layer where the first hole overlaps with the first electrode and another first hole in a second position in the second protective layer where the other first hole overlaps with the second electrode in the plan view viewed in the direction of a normal to the substrate, forming a second hole in the bottom surface of the first hole formed in the first position, the second hole having an opening area smaller than the opening area of the first hole, to form a first through hole that exposes part of the first electrode, and forming a third hole in the bottom surface of the first hole formed in the second position, the third hole having an opening area smaller than the opening area of the second hole, to form a second through hole that exposes part of the second electrode. 
     In the method for manufacturing the light emitting apparatus according to the other aspect of the present disclosure, a plurality of first columnar sections each including a first light emitting layer may be formed as the first light emitting section, and a plurality of second columnar sections each including a second light emitting layer may be formed as the second light emitting section. 
     A projector according to another aspect of the present disclosure may have the configuration below. 
     The projector according to the other aspect of the present disclosure includes the light emitting apparatus according to the aspect of the present disclosure.