Display device

Abstract

Provided is a display device having a plurality of light-emitting elements arrayed on a substrate. Each of the light-emitting elements comprises: a light-emitting layer; a first electrode and a second electrode sandwiching the light-emitting layer from above and below; a photonic crystal structure provided so as to face the light-emitting layer across the second electrode; and an insulating layer that is provided between the first electrode and the light-emitting layer and has an opening over the center of the photonic crystal structure. The photonic crystal structure comprises: a plurality of columnar bodies arrayed periodically in a predetermined periodic length in a first region overlapping the opening and a second region not overlapping the opening; and a plurality of defects that disrupt the periodicity of the array of the plurality of columnar bodies and that are provided within the first region so as to be spaced apart from one another by three periods or more.

Description

display device

[0001] This disclosure relates to a display device.

[0002] In recent years, the development of display devices using self-luminescent elements such as electroluminescent (EL) elements has progressed. In such display devices, for example, multiple light-emitting elements, each having a stacked structure composed of a lower electrode, a light-emitting layer stacked on the lower electrode, and an upper electrode stacked on the light-emitting layer, are arranged on a substrate. When a predetermined voltage is supplied to the lower electrode and the upper electrode, the light-emitting layer sandwiched between the lower electrode and the upper electrode emits light.

[0003] Japanese Patent Publication No. 2012-253288

[0004] Because the aforementioned display devices can display high-quality and high-resolution images, they are used not only in direct-view display devices such as monitors, but also in small display devices such as EVFs (Electronic View Finders) and HMDs (Head-Mounted Displays). Furthermore, in order to use these display devices in applications such as VR (Virtual Reality) and AR (Augmented Reality), there is a need to increase the frontal radiant intensity of light while suppressing the increase in power consumption.

[0005] Therefore, this disclosure proposes a display device that can increase the frontal radiation intensity of light while suppressing an increase in power consumption.

[0006] According to this disclosure, a display device is provided having a plurality of light-emitting elements arranged on a substrate, wherein each light-emitting element comprises a light-emitting layer, a first electrode and a second electrode sandwiching the light-emitting layer from above and below, a photonic crystal structure provided so as to face the light-emitting layer with the second electrode in between, and an insulating layer provided between the first electrode and the light-emitting layer and having an opening on the center of the photonic crystal structure, wherein the photonic crystal structure has a plurality of columnar bodies arranged periodically with a predetermined period length in a first region overlapping the opening and a second region not overlapping the opening, and a plurality of defects within the first region that are spaced apart from each other for three or more periods and disrupt the period of the arrangement of the plurality of columnar bodies, wherein the first region of the photonic crystal structure is divided into a plurality of unit units, the plurality of unit units are arranged at positions that are n (an integer of 2 or more) rotationally symmetric with respect to the center of the photonic crystal structure as the rotational center, and each unit unit has the defects at least at three locations.

[0007] This is a schematic diagram showing an example of the overall configuration of a display device according to an embodiment of this disclosure. This is a circuit diagram showing an example of a subpixel of a display device according to an embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a light-emitting element according to the first embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a photonic crystal structure according to the first embodiment of this disclosure. This is an enlarged view of a part of the photonic crystal structure according to the first embodiment of this disclosure. This is an enlarged view of a part of the photonic crystal structure according to the second embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a light-emitting element according to the third embodiment of this disclosure. This is a schematic diagram (1) showing an example of the cross-sectional configuration of a display panel according to the fourth embodiment of this disclosure. This is a schematic diagram (2) showing an example of the cross-sectional configuration of a display panel according to the fourth embodiment of this disclosure. This is a conceptual diagram (1) for explaining the relationship between the normal LN passing through the center of the light-emitting part, the normal LN' passing through the center of the lens member, and the normal LN'' passing through the center of the wavelength selection part. This is a conceptual diagram (2) for explaining the relationship between the normal LN passing through the center of the light-emitting part, the normal LN' passing through the center of the lens member, and the normal LN'' passing through the center of the wavelength selection part. This is a conceptual diagram (part 3) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (part 4) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (part 5) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (part 6) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (No. 7) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN'' passing through the center of the wavelength selection part. This is a schematic cross-sectional view illustrating the first example of the resonator structure. This is a schematic cross-sectional view illustrating the second example of the resonator structure. This is a schematic cross-sectional view illustrating the third example of the resonator structure. This is a schematic cross-sectional view illustrating the fourth example of the resonator structure. This is a schematic cross-sectional view illustrating the fifth example of the resonator structure.This is a schematic cross-sectional view illustrating a sixth example of a resonator structure. This is a schematic cross-sectional view illustrating a seventh example of a resonator structure. This is a front view showing an example of the appearance of a digital still camera. This is a rear view showing an example of the appearance of a digital still camera. This is an external view of a head-mounted display. This is an external view of a see-through head-mounted display. This is an external view of a television system. This is an external view of a smartphone. This is a diagram (1) showing the internal configuration of an automobile. This is a diagram (2) showing the internal configuration of an automobile.

[0008] Preferred embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configuration will be denoted by the same reference numeral to avoid redundant explanation. In addition, in this specification and drawings, multiple components having substantially the same or similar functional configurations may be distinguished by adding a different alphabet after the same reference numeral. However, if there is no particular need to distinguish each of multiple components having substantially the same or similar functional configurations, only the same reference numeral will be used.

[0009] Furthermore, the drawings referenced in the following description are intended to illustrate and facilitate understanding of one embodiment of this disclosure, and for the sake of clarity, the shapes, dimensions, ratios, etc. shown in the drawings may differ from those of the actual product. In addition, the apparatus shown in the drawings may be modified in design as appropriate, taking into consideration the following description and known technology.

[0010] Furthermore, in the following descriptions of circuits (electrical connections), unless otherwise specified, "electrically connected" means connecting multiple elements in such a way that electricity (signals) can conduct through them. In addition, "electrically connected" in the following descriptions includes not only cases where multiple elements are directly and electrically connected, but also cases where they are indirectly and electrically connected through other elements.

[0011] The explanation will proceed in the following order: 1. Display device according to the embodiment of this disclosure 1.1 Display device 1.2 Pixel 2. Background 3. First embodiment 4. Second embodiment 5. Third embodiment 6. Fourth embodiment 7. Summary 8. Modifications 8.1 Modification 1 8.2 Modification 2 9. Application examples 10. Supplement

[0012] <<1. Display Device According to the Embodiment of the Present Disclosure>> <1.1 Display Device> First, with reference to Figure 1, an example of the overall configuration of a display device 10 according to the embodiment of the present disclosure, which is used as a display device or lighting device, will be described. Figure 1 is a schematic diagram showing an example of the overall configuration of a display device 10 according to the embodiment of the present disclosure.

[0013] The display device 10 is, for example, a device in which light-emitting elements such as LEDs (Light Emitting Diodes) or μLEDs are formed in an array. Such a display device 10 can be applied to, for example, display devices for VR (Virtual Reality), MR (Mixed Reality), or AR (Augmented Reality), electronic viewfinders (EVFs), or small projectors. The display device 10 can also be applied to various lighting devices.

[0014] Furthermore, in the embodiments of this disclosure, the light-emitting element may be a self-emitting element as well as a current-driven electro-optic element. For example, in addition to LEDs, current-driven electro-optic elements can include OLEDs (Organic Light Emitting Diodes), Micro-OLEDs, semiconductor laser elements, and the like.

[0015] As shown in Figure 1, the display device 10 has a configuration comprising a pixel array section 20 in which a plurality of subpixels 400, including light-emitting elements, are arranged in a matrix-like (two-dimensional) arrangement on a semiconductor substrate (not shown), and a drive circuit section arranged around the pixel array section 20. The drive circuit section includes, for example, a horizontal drive circuit 11 and a vertical drive circuit 12 mounted on the same display panel 40 as the pixel array section 20, and drives each subpixel 400 of the pixel array section 20.

[0016] Here, if the display device 10 is color-compatible, one pixel (unit pixel) that forms a color image is composed of multiple subpixels 400. More specifically, in a color-compatible display device 10, one pixel may be composed of three subpixels 400, for example, a subpixel 400R that emits red light, a subpixel 400G that emits green light, and a subpixel 400B that emits blue light. Furthermore, a pixel may be composed of, for example, one, two, or more subpixels 400, and is not particularly limited. Also, one pixel is not limited to a combination of three primary color subpixels 400, such as red, green, and blue, but may also be composed of three primary color subpixels 400 with one or more additional subpixels 400 of different colors added to form one pixel. More specifically, the display device 10 may, for example, add a sub-pixel 400 that emits white light to improve brightness, or add at least one sub-pixel 400 that emits complementary light to expand the color reproduction range, thereby forming a single pixel.

[0017] Furthermore, in this embodiment, a single pixel is not limited to being composed of multiple subpixels 400 that emit different light, as described above, but may be composed of multiple subpixels 400 that emit light of the same color. Here, a pixel means the smallest unit (pixel) that is controlled when controlling the light emission of the display device 10, and is composed of multiple subpixels 400 that are treated as a single unit during control. In other words, in this embodiment, the display device 10 has multiple pixels arranged in a matrix on the display panel 40.

[0018] In detail, the horizontal drive circuit 11 scans each sub-pixel 400 row by row (in Figure 1, the direction extending along the X direction is called the row direction) when writing a signal to each sub-pixel 400, and can sequentially supply a scan signal to each scan line SCLm. The horizontal drive circuit 11 can be configured, for example, by a shift register that sequentially shifts (transfers) start pulses in synchronization with the input clock pulse.

[0019] Furthermore, the vertical drive circuit 12 can supply a signal voltage corresponding to the brightness information supplied from a signal source (not shown) to selected sub-pixels 400 in column units (in Figure 1, the direction extending along the Y direction is called the column direction) via the signal line DTLn.

[0020] In the embodiments of this disclosure, the configuration of the display device 10 is not limited to the configuration shown in Figure 1. That is, the configuration shown in Figure 1 is merely an example, and the display device 10 according to the embodiments of this disclosure can take various configurations.

[0021] <1.2 Pixels> Next, the circuit configuration of the sub-pixel 400 of the display device 10 according to the embodiment of the present disclosure shown in Figure 1 will be described. Figure 2 is a circuit diagram showing an example of the sub-pixel 400 of the display device 10 according to the embodiment of the present disclosure, and more specifically, it is a schematic circuit diagram for explaining the wiring relationship in the sub-pixel 400 of the mth row and nth column.

[0022] In the display device 10, as previously described, the subpixels 400 including the light-emitting element 100 have scan lines SCLs that extend in the row direction (X direction in Figure 1). ｍ and the signal line DTL extending in the column direction (Y direction in Figure 1) ｎ They are arranged in a two-dimensional matrix while connected to each other.

[0023] Furthermore, as shown in Figure 2, the display device 10 has a power supply line PS1 that supplies a drive voltage to the subpixels 400. ｍ It also has a common power supply line PS2 that is connected to all sub-pixels 400 in common. And power supply line PS1 ｍ A predetermined drive voltage VCC etc. is supplied from the power supply unit (not shown), and a common voltage V is supplied to the common power supply line PS2. Ｃａｔis supplied (for example, to a ground potential).

[0024] Here, let the number of scanning lines SCL and power supply lines PS1 be M each. The sub-pixel 400 in the m-th row (where m = 1, 2,..., P) is connected to the m-th scanning line SCL ｍ , the m-th power supply line PS1 ｍ and constitutes one display element row. In FIG. 2, only the scanning line SCL ｍ and the power supply line PS1 ｍ are shown. Also, let the number of signal lines DTL be N. The sub-pixel 400 in the n-th column (where n = 1, 2,..., N) is connected to the n-th signal line DTL ｎ . In FIG. 2, only the signal line DTL ｎ is shown. Hereinafter, the sub-pixel 400 located at the m-th row and n-th column may be referred to as the (n, m)-th sub-pixel 400.

[0025] And, as described above, the display device 10 is sequentially scanned in row units by the scanning signal from the horizontal drive circuit 11. Specifically, in the display device 10, the M sub-pixels 400 arranged in the m-th row are simultaneously driven. In other words, in the M sub-pixels 400 arranged along the row direction, the timing of their light emission / non-light emission is controlled in units of the rows to which they belong. For example, when the display frame rate of the display device 10 is FR (times / second), the scanning period per row (so-called horizontal scanning period) when the display device 10 is sequentially scanned in row units is less than (1 / FR)×(1 / P) seconds.

[0026] Also, as shown in FIG. 2, the sub-pixel 400 is composed of a light-emitting element 100 and a drive circuit for driving the same. The light-emitting element 100 is an inorganic electroluminescence light-emitting element or an organic electroluminescence light-emitting element. The drive circuit is composed of a writing transistor TR Ｗ , a drive transistor TR Ｄ , and a capacitor portion C １ . The drive transistor TR ＤWhen current flows through the light-emitting element 100, the light-emitting element 100 can emit light. Each transistor is composed of, for example, a p-channel type field-effect transistor.

[0027] As shown in Figure 2, in the sub-pixel 400, the drive transistor TR Ｄ One of the source / drain regions is the capacitance section C １ One end and power supply line PS1 ｍ The source / drain region is electrically connected to one end of the light-emitting element 100 (specifically, the anode electrode). Ｄ The gate electrode is the writing transistor TR Ｗ It is connected to the other source / drain region, and the capacitance section C １ It is electrically connected to the other end.

[0028] Also, as shown in Figure 2, the writing transistor TR Ｗ One of the source / drain regions is the signal line DTL ｎ It is electrically connected to the writing transistor TR Ｗ The gate electrode is the scan line SCL ｍ It is electrically connected to it.

[0029] Furthermore, as shown in Figure 2, the other end of the light-emitting element 100 (specifically, the cathode electrode) is electrically connected to the common power supply line PS2. In addition, a predetermined cathode voltage V is supplied to the common power supply line PS2. Ｃａｔ This is supplied. In Figure 2, the capacitance of the light-emitting element 100 is indicated by the code C. ＥＬ It is represented as follows.

[0030] The overview of the driving of the sub-pixel 400 will be described. In the sub-pixel 400, the signal line DTL is transmitted from the vertical drive circuit 12. ｎ With a voltage corresponding to the brightness of the image to be displayed supplied, the writing transistor TR is activated by a scanning signal from the horizontal drive circuit 11. Ｗ When the capacitance C is in a conductive state, １ A voltage corresponding to the brightness is written to it. (Writing transistor TR) Ｗ After the capacitor is de-conducted, the capacitance part C １The drive transistor TR operates according to the voltage held in Ｄ When an electric current flows through it, the light-emitting element 100 emits light.

[0031] In the embodiments of this disclosure, the configuration of the drive circuit that controls the light emission of the light-emitting element 100 is not limited to the configuration shown in Figure 2. Therefore, the configuration shown in Figure 2 is merely an example, and various configurations can be taken in the display device 10 according to the embodiments of this disclosure.

[0032] <<2. Background>> Next, before describing the details of the embodiments of this disclosure, we will explain the background that led the inventors to create the embodiments of this disclosure.

[0033] As described above, the display device 10 can display high-quality and high-resolution images, and as explained earlier, it is used not only in direct-view display devices such as monitors, but also in small display devices such as EVFs and HMDs. In recent years, in order to use these display devices particularly in applications such as VR and AR, there has been a need to increase the frontal radiation intensity of light while suppressing the increase in power consumption of the display device 10.

[0034] Therefore, in the conventional technology, it has been devised to provide a photonic crystal structure in the light-emitting element 100. A photonic crystal structure is an artificial crystal with a nanoperiodic structure in which materials with different refractive indices are arranged periodically at intervals approximately the same as the wavelength of light, and due to the band gap effect of this periodic structure, light of a predetermined wavelength can be confined inside it. Furthermore, in the conventional technology, it has also been devised to introduce areas where the periodic structure is disrupted (minute defects) into the above-mentioned photonic crystal structure. In detail, light with a wavelength corresponding to the periodic structure of the photonic crystal structure is confined and resonates in the defects and the regions surrounding the defects, so the defects and the regions surrounding the defects function as optical resonators. In other words, in the conventional technology, by providing a photonic crystal structure with introduced defects inside the light-emitting element 100, the intensity of the light (brightness, color purity) can be increased by confining and resonating light within the photonic crystal structure.

[0035] However, in conventional technology, the structure of the light-emitting element 100 and the photonic crystal structure have not been thoroughly examined, so even with the aforementioned photonic crystal structure, there were limitations in efficiently increasing the frontal radiation intensity of light.

[0036] Therefore, in light of these circumstances, the inventors diligently studied the optimization of the structure of the light-emitting element 100 and the photonic crystal structure, as well as the optimization of the combined structure, and have come up with the embodiments of the present disclosure described below. According to the embodiments of the present disclosure, it is possible to increase the frontal radiation intensity of light while suppressing an increase in power consumption. The details of the embodiments of the present disclosure created by the inventors will be described in order below.

[0037] <<3. First Embodiment>> First, the detailed configuration of the light-emitting element 100 according to the first embodiment of this disclosure will be described with reference to Figures 3A, 3B, and 3C. Figure 3A is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and Figure 3B is a schematic diagram showing an example of the cross-sectional configuration of the photonic crystal structure 120 according to this embodiment. Furthermore, Figure 3C is an enlarged view of a part of the photonic crystal structure according to this embodiment.

[0038] In the display device 10 according to this embodiment, a plurality of light-emitting elements 100 that emit light upward are arranged in a matrix in a predetermined area on the substrate 110 (see Figure 3A). Each of the light-emitting elements 100 can be, for example, a light-emitting element 100 that emits red light, a light-emitting element 100 that emits green light, or a light-emitting element 100 that emits blue light.

[0039] As shown in Figure 3A, the light-emitting element 100 according to this embodiment has a laminated structure in which a photonic crystal structure 120, a lower electrode (second electrode) 130, a light-emitting layer 132, an insulating layer 140, an upper electrode (first electrode) 134, and a protective film 150 are sequentially stacked on a substrate 110 in this order. The details of each element of the light-emitting element 100 according to this embodiment will be described in order below.

[0040] (Substrate 110) The substrate 110 can be formed from a transparent material such as silicon oxide (SiOx) or a semiconductor material such as silicon.

[0041] (Photonic crystal structure 120) The photonic crystal structure 120 is an artificial crystal with a nanoperiodic structure in which materials with different refractive indices are arranged periodically at intervals approximately the same as the wavelength of light. Due to the band gap effect of this periodic structure, light of a predetermined wavelength can be confined inside. Furthermore, by introducing local periodic disturbances (in this specification, periodic disturbances are referred to as "defects") into the photonic crystal structure 120, light in the band gap range determined by the periodic structure is confined in the region of the defect and its surrounding area, and thus the above region can function as an optical resonator.

[0042] In detail, in this embodiment, as shown in Figure 3A, the photonic crystal structure 120 is provided so as to face the light-emitting layer 132 with the lower electrode 130 in between. Furthermore, the photonic crystal structure 120 has a structure in which a plurality of columnar bodies 122 having a nanoscale diameter are periodically arranged within the photonic crystal layer 124. Furthermore, each columnar body 122 penetrates the photonic crystal layer 124 along the film thickness direction of the photonic crystal layer 124. The columnar bodies 122 can be made of a material with a different refractive index from the material of the photonic crystal layer (surrounding layer) 124, or they can be voids. For example, if the photonic crystal layer 124 is formed from silicon nitride (SiNx) (refractive index 1.83), the columnar bodies 122 can be formed from hydrogen silsesquioxane (HSQ) (refractive index 1.4). In this embodiment, it is preferable that the columnar body 122 is formed from a material with a different refractive index from the surrounding material, which makes deformation of the photonic crystal structure 120 less likely compared to the case where it is made of a cavity.

[0043] Furthermore, in this embodiment, as will be described later, each of the multiple columnar bodies 122 is positioned at a location that is point-symmetric with respect to the center of the photonic crystal structure 120.

[0044] Furthermore, in this embodiment, as shown in Figure 3A, multiple defects 126 are introduced in the central region of the photonic crystal structure 120 where the periodic arrangement of columnar bodies 122 is disrupted; in this example, defects 126 where columnar bodies 122 are absent. In this embodiment, light with a wavelength corresponding to the periodic structure of the photonic crystal structure 120 is confined and resonates in the defects 126 and the surrounding regions of the defects 126. Specifically, in the planar direction of the photonic crystal structure 120, the bandgap effect due to the periodic structure confines light to the defects 126 and the surrounding regions of the defects 126. In this embodiment, a resonance mode localized in the above region is generated, and the defects 126 and the surrounding regions of the defects 126 function as optical resonators. Therefore, in this embodiment, the defects 126 and the surrounding regions of the defects 126 confine and resonate light from the light-emitting layer 132, thereby efficiently increasing the light intensity (brightness, color purity).

[0045] Furthermore, in this embodiment, since the volume of defect 126 and the surrounding region of defect 126 are extremely small, the mode volume (V) of the resonator is very small. Therefore, according to this embodiment, by using the resonator, the intensity of light (luminance, color purity) can be efficiently increased by the Purcell effect. Specifically, since the photon density in the optical resonator is proportional to Q / V (where Q is the Q value of the resonator), by making the mode volume small and the Q value high, light can be confined in a small region at an extremely high density for a long time. Therefore, with such an optical resonator, the speed and intensity of luminescence recombination can be increased by the Purcell effect.

[0046] In addition, in this embodiment, most of the light is extracted from the defects 126 and the surrounding regions of the photonic crystal structure 120 in the direction of the film thickness of the photonic crystal structure 120. In this embodiment, since the brightness of the defects 126 and the surrounding regions of the photonic crystal structure 120 is high, it can be said that the region that radiates light most directly forward is limited.

[0047] Further details of the photonic crystal structure 120 according to this embodiment will be described later with reference to Figures 3B and 3C.

[0048] (Lower electrode 130) In this embodiment, as shown in Figure 3A, the lower electrode 130 is provided together with the upper electrode 134, which will be described later, so as to sandwich the light-emitting layer 132 from above and below. More specifically, the lower electrode 130 may be formed of a transparent conductive material that has good light transmittance to visible light (for example, visible light with a wavelength of about 360 nm to 780 nm). For example, the lower electrode 130 can be formed from a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO).

[0049] (Light-emitting layer 132) The light-emitting layer 132 has a structure in which, for example, a hole injection layer, a hole transport layer, organic light-emitting layers of each color that emit light of each color, and an electron transport layer are sequentially stacked from bottom to top. The organic light-emitting layer may be a multilayer structure in which different light-emitting materials that emit light of the same color are stacked, or it may be a multilayer structure in which different light-emitting materials that emit light of different colors are stacked. Note that the stacking order of the light-emitting layer 132 is not limited to the order described above, and may be stacked in an inverted order.

[0050] The hole-injection layer can be composed of, for example, hexaazatriphenylene (HAT).

[0051] The hall transport layer can be composed of, for example, α-NPD[N,N'-di(1-naphthyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine].

[0052] The red organic light-emitting layer generates red light when an electric field is applied, as some of the holes injected from the lower electrode 130 via the hole injection layer and hole transport layer recombine with some of the electrons injected from the upper electrode 134 via the electron transport layer. The red light-emitting layer includes, for example, at least one of the following: a red light-emitting material, a hole transport material, an electron transport material, and a dual charge transport material. The red light-emitting material may be fluorescent or phosphorescent. Specifically, the red light-emitting layer can be composed of, for example, 4,4-bis(2,2-diphenylbinin)biphenyl (DPVBi) mixed with 30% by weight of 2,6-bis[(4'-methoxydiphenylamino)styryl]-1,5-dicyanonaphthalene (BSN).

[0053] The blue organic light-emitting layer generates blue light when an electric field is applied, as some of the holes injected from the lower electrode 130 via the hole injection layer, hole transport layer, and light emission separation layer recombine with some of the electrons injected from the upper electrode 134 via the electron transport layer. The blue light-emitting layer includes, for example, at least one of the following: a blue light-emitting material, a hole transport material, an electron transport material, and a dual charge transport material. The blue light-emitting material may be fluorescent or phosphorescent. Specifically, the blue light-emitting layer can be composed of, for example, a mixture of DPVBi and 2.5% by weight of 4,4'-bis[2-{4-(N,N-diphenylamino)phenyl}vinyl]biphenyl (DPAVBi).

[0054] The green organic light-emitting layer generates green light when an electric field is applied, as some of the holes injected from the lower electrode 130 via the hole injection layer, hole transport layer, and light emission separation layer recombine with some of the electrons injected from the upper electrode 134 via the electron transport layer. The green light-emitting layer includes, for example, at least one of the following: a green light-emitting material, a hole transport material, an electron transport material, and a dual charge transport material. The green light-emitting material may be fluorescent or phosphorescent. Specifically, the green light-emitting layer can be composed of, for example, a mixture of DPVBi with 5% by weight of coumarin 6.

[0055] The electron transport layer is, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Alq ３ (Aluminum quinolinol), Bphen (basophenanthroline), etc. are used. The electron transport layer consists of at least one layer and may include an electron transport layer doped with an alkali metal or alkaline earth metal. The electron transport layer doped with an alkali metal or alkaline earth metal may be, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Alq as the host material. ３ The material can be composed of aluminum quinolinol, Bphen (basophenanthroline), etc., doped with alkali metals such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs), or alkaline earth metals such as magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba) by co-depositing, for example, at a concentration of 0.5 to 15% by weight.

[0056] Furthermore, an electron injection layer may be provided between the electron transport layer and the upper electrode 134. The electron injection layer is for increasing electron injection from the cathode and can be composed of an alkali metal or alkaline earth metal in its elemental form, a compound containing them, or a mixture containing them. For example, the electron injection layer can be composed of lithium (Li) or lithium fluoride (LiF), etc.

[0057] Furthermore, a buffer layer may be provided between the electron transport layer and the upper electrode 134. The buffer layer is intended to mitigate process damage to the light-emitting layer 132 during the deposition of the upper electrode 134. The buffer layer may be made of, for example, magnesium (Mg), magnesium-silver alloy (MgAg), calcium (Ca), lithium (Li), lithium fluoride (LiF), or lithium carbonate (Li ２ CO ３ ), cesium (Cs), cesium carbonate (Cs ２ CO ３ It can be composed of elements of alkali metals or alkaline earth metals, compounds containing them, or mixtures containing them.

[0058] In the above description, the light-emitting layer 132 was described as including an organic light-emitting layer (organic light-emitting material), but in this embodiment, it is not limited to this. In this embodiment, the light-emitting layer 132 can be formed from an inorganic light-emitting material, a perovskite material, a colloidal quantum dot (QD) material, or a mixture thereof.

[0059] In this embodiment, the inorganic light-emitting material can be composed of, for example, GaN-based compound semiconductors (including AlGaN mixed crystals, AlInGaN mixed crystals, and GaInN mixed crystals), AlGaInAs-based compound semiconductors, AlGaInP-based compound semiconductors, ZnSe-based compound semiconductors (for example, including ZnS, ZnSSe, and ZnMgSSe), and ZnO-based compound semiconductors. More specifically, AlInGaN-based compound semiconductors can be GaN, AlGaN, InGaN, and AlInGaN. Furthermore, these compound semiconductors may optionally contain boron (B) atoms, thallium (Tl) atoms, arsenic (As) atoms, phosphorus (P) atoms, antimony (Sb) atoms, and the like.

[0060] Furthermore, in this embodiment, the perovskite material is, for example, ABX ３ The composition can be a metal halide perovskite. For example, here A is cesium (Cs) and a methylamino group (CH ３ NH ３ , HC (NH ２ ) ２ ) etc., B can be lead (Pb), tin (Sn), etc., and X can be chlorine (Cl), bromine (Br), iodine (I), etc. Furthermore, the perovskite material may be a quantum dot structure, as described later, in addition to the usual bulk structure.

[0061] Furthermore, colloidal quantum dot materials are nanoscale structures with unique optical properties that follow quantum mechanics, and typically have a diameter of several nanometers. Generally, colloidal quantum dot materials allow for adjustment of the band gap by size, thus enabling particle size-dependent optical confinement. Colloidal quantum dot materials have the characteristic of being able to adjust the wavelength of light to be confined by the particle size, and not only do they have a narrow spectral full width at half maximum, but also high quantum efficiency. In detail, a colloidal quantum dot material has, for example, a core and a shell that covers the surface of the core. The core and shell can be formed from, for example, an inorganic compound material. Examples of inorganic compound materials include CdSe, CdS, CdZnSe, CdTe, ZnSe, ZnS, ZnTe, and InP.

[0062] (Upper electrode 134) In this embodiment, the upper electrode 134 may be formed from a transparent conductive material that has good light transmittance to visible light, for example. For example, the upper electrode 134 can be formed from a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO).

[0063] (Insulating layer 140) In this embodiment, as shown in Figure 3A, the insulating layer 140 is provided between the upper electrode 134 and the light-emitting layer 132. The insulating layer 140 can be formed from an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride (SiOxNy). The insulating layer 140 may also be a single layer or a multilayer film of the above material. Furthermore, in this embodiment, the insulating layer 140 has a circular opening 142 provided on the defect 126 located at the center of the photonic crystal structure 120 and the surrounding region. The upper electrode 134 is positioned within the opening 142. In this embodiment, the insulating layer 140 having the opening 142 limits the region through which current flows.

[0064] In detail, in this embodiment, the aperture 142 is located above a plurality of defects 126 in the photonic crystal structure 120, which is the region that radiates light most directly forward. On the other hand, the insulating layer 140 is located above a region of the photonic crystal structure 120 where the plurality of defects 126 are not provided. In this embodiment, by using this structure, the region in which current preferentially flows is limited to the light-emitting layer 132 located above the region that radiates light most directly forward (resonator). As a result, according to this embodiment, the power consumption of the light-emitting element 100 can be reduced while increasing the frontal radiation intensity of light. The details of the positional relationship between the defects 126 and the aperture 142 will be described later.

[0065] (Protective film 150) The protective film 150 is provided to suppress damage to the light-emitting layer 132 and the like during the manufacturing process and contamination from the external environment. The protective film 150 is preferably formed from, for example, an inorganic material or an organic material that has low hygroscopicity and light transmittance to visible light. The protective film 150 may also have a single-layer structure or a multi-layer structure. For example, inorganic materials include silicon oxide, silicon nitride, silicon oxynitride, titanium oxide (TiOx), and aluminum oxide (AlOx). Organic materials include, for example, thermosetting resins and photosensitive resins. Photosensitive resins include, for example, ultraviolet curable resins. Specifically, organic materials include, for example, acrylic resins, polyimide resins, novolac resins, and epoxy resins. Furthermore, the protective film 150 may be an ALD (Atomic Layer Deposition) layer to enhance the effect of suppressing moisture penetration.

[0066] Furthermore, with reference to Figures 3B and 3C, the details of the photonic crystal structure 120 according to this embodiment will be described. As shown in Figure 3B, the photonic crystal structure 120 has, for example, a regular hexagonal shape. More specifically, the photonic crystal structure 120 has a region that overlaps with the opening 142 of the insulating layer 140 (a first region) and a region that does not overlap with the opening 142 (a second region). The photonic crystal structure 120 also has a plurality of columnar bodies 122 provided at positions that are rotationally symmetric (point symmetric) with respect to the center of the photonic crystal structure 120. More specifically, as shown in Figure 3B, the plurality of columnar bodies 122 have a cylindrical shape and are arranged periodically in a hexagonal lattice (in other words, they are arranged at the intersections of the hexagonal lattice and at the center of each hexagon of the hexagonal lattice). Furthermore, the plurality of columnar bodies 122 are arranged in both the region that overlaps with the opening 142 and the region that does not overlap with the opening 142.

[0067] In this embodiment, as shown in Figures 3B and 3C, the period length (distance between the centers of two adjacent columnar bodies 122) in the periodic arrangement of the plurality of columnar bodies 122 is assumed to be a. In this embodiment, the period length a can be obtained by the relationship between the resonant frequency f of the resonator containing the defect 126 and the emission peak wavelength λ (for example, 600 nm) of the light-emitting layer 132, i.e., f = a / λ. More specifically, in the photonic crystal structure 120 according to this embodiment, for six or more columnar bodies 122 excluding the columnar bodies 122 around the defect 126 (more specifically, the "first period columnar bodies" and "second period columnar bodies" described later), the average value of the distance between the centers of two adjacent columnar bodies 122 is assumed to be equal to the period length a.

[0068] Furthermore, in this embodiment, the diameter D of the multiple columnar bodies 122 is smaller than the period length a. Moreover, in this embodiment, the multiple columnar bodies 122 have the same diameter D, except for the multiple columnar bodies 122 located around the defect 126 described later (more specifically, a part of the "first period columnar bodies" described later). More specifically, in this embodiment, the average value of the diameters of the multiple columnar bodies (fourth columnar bodies) 122, excluding the multiple columnar bodies 122 located around the defect 126 described later, is equal to the diameter D. In this embodiment, for example, the diameter D can be 0.26 times the period length a.

[0069] Furthermore, in this embodiment, as previously described, the photonic crystal structure 120 has multiple defects 126 introduced in areas where the periodic arrangement of columnar bodies 122 is disrupted, that is, areas where columnar bodies 122 are absent. Specifically, in this embodiment, as shown in Figure 3B, multiple defects 126 are introduced in the region (first region) that overlaps with the opening 142 located in the center of the photonic crystal structure 120. Furthermore, in this embodiment, the multiple defects 126 are not provided in the region (second region) that does not overlap with the opening 142.

[0070] In other words, in this embodiment, the opening 142 of the insulating layer 140 is located above a plurality of defects 126 in the photonic crystal structure 120, which is the region that radiates light most directly forward. On the other hand, the insulating layer 140 is located above a region of the photonic crystal structure 120 where the plurality of defects 126 are not provided. In this embodiment, by providing the insulating layer 140 having the opening 142 that limits the region in which current flows, the region in which current flows preferentially is limited to the light-emitting layer 132 located above the region that radiates light most directly forward (resonator). As a result, according to this embodiment, the frontal radiation intensity of light can be increased while suppressing the power consumption of the light-emitting element 100.

[0071] In addition, in this embodiment, it is preferable that the multiple defects 126 are spaced at least three periods apart from each other (in other words, at a distance of three times the period length a). In this embodiment, by doing so, the band gap effect due to the periodic structure of the multiple columnar bodies 122 can be maintained, and light with a predetermined wavelength can be confined to the defects 126 and the region surrounding the defects 126.

[0072] In this embodiment, as shown in Figure 3B, the defect 126 located at the center of the photonic crystal structure 120 ａ Multiple defects 126 are located at each of the positions that are point-symmetric with respect to the given location. ｂ ~126 ｇ A is provided. In the following, the location of the defects 126 will be described using a unit unit that includes three or more defects 126. Here, the unit unit is defined as at least a defect (first defect) 126a located at the center of the photonic crystal structure 120, as shown in Figure 3C, and a defect (second defect) 126 ｂ and defect (third defect) 126 ｃ This includes the following. Furthermore, the photonic crystal structure 120 can be divided into a plurality of unit units. The plurality of unit units are arranged at positions that are n (an integer of 2 or more) rotationally symmetric with respect to the defect (first defect) 126a located at the center of the photonic crystal structure 120. In other words, one unit unit is divided into defect 126 ａ When rotated by (360 / n) degrees around the center, defects 126 within a unit unit ｂ , 126 ｃ This refers to defects 126 in other unit units. ｂ , 126 ｃ It is superimposed on. Furthermore, one unit is defective 126 ａ By repeating a rotation of (360 / n) degrees around the center n times, defects 126 within one unit unit ｂ , 126 ｃ It returns to its original position. For example, in the example shown in Figure 3B, the unit units are placed in positions that are three times symmetrical.

[0073] Furthermore, within the unit, defect 126 ｂDefect 126 ｃ The location of the defect is explained. In the example shown in Figure 3C, defect 126 ａ And along the Y-axis direction, defect 126 ａ Adjacent defect 126 ｂ Line segment 180 connecting to ａ Defect 126 ａ The line segment 180 is obtained by rotating it by an angle E (for example, 60 degrees) around the center. ｂ Defect 126c is located beyond that point.

[0074] Furthermore, in the region overlapping with the opening 142 of the photonic crystal structure 120 according to this embodiment, a plurality of unit units are regularly arranged around the center of the photonic crystal structure 120. Specifically, in the example shown in Figure 3B, a defect 126 is located at the center of the photonic crystal structure 120. ａ It is located, defect 126 ａ There are six defects at the vertices of a regular hexagon centered on 126 ｂ , 126 ｃ , 126 ｄ , 126 ｅ , 126 ｆ , 126 ｇ It is located there.

[0075] Furthermore, in this embodiment, as shown in Figure 3B, the defect 126 located at the center of the photonic crystal structure 120 ａ It is preferable that the columnar bodies 122 are arranged in at least four periods toward the outer periphery of the photonic crystal structure 120, starting from the defect 126 furthest from the center of the photonic crystal structure 120. In other words, the defect 126 located at the center of the photonic crystal structure 120 ａ Preferably, at least three or more columnar bodies 122 are provided extending from the defect 126 furthest from the photonic crystal structure 120 toward the outer periphery. In this embodiment, this maintains the bandgap effect due to the periodic structure of the multiple columnar bodies 122, and allows light of a predetermined wavelength to be confined to the defect 126 and the region surrounding the defect 126.

[0076] Furthermore, in this embodiment, as shown in Figure 3C, the above unit unit has a defect 126ａ Adjacent to it is a defect 126 ａ Six columnar bodies (first columnar bodies) 122 surrounding the defect 126 ａ１ and a defect 126 ｂ Adjacent to it is a defect 126 ｂ Six columnar bodies (second columnar bodies) 122 surrounding the defect 126 ｂ１ and a defect 126 ｃ Adjacent to it is a defect 126 ｃ Six columnar bodies (third columnar bodies) 122 surrounding the defect 126 ｃ１ and has. And the center of the columnar body 122 ａ１ is separated from the center of the defect 126 by a period length a, and the center of the columnar body 122 ａ is separated from the center of the defect 126 by a period length a, and the center of the columnar body 122 ｂ１ is separated from the center of the defect 126 ｂ by a period length a, and the center of the columnar body 122 ｃ１ is separated from the center of the defect 126 ｃ by a period length a. In other words, the center of the columnar body 122 ａ１ and the center of the columnar body 122 ｂ１ and the center of the columnar body 122 ｃ１ are at positions determined by the periodic arrangement of the columnar bodies 122. Also, in the following description, these columnar bodies 122 ａ１ , 122 ｂ１ , 122[[ID=4)), 122is adjacent to the defects 126 ａ , 126 ｂ , 126 ｃ and, in the relative positional relationship with the defects 126 ａ , 126 ｂ , 126 ｃ are adjacent and separated by a period length a, and are also referred to as "columnar bodies of the first period".

[0077] Also, in this embodiment, the diameter of the columnar body 122 ａ１ and the diameter of the columnar body 122 ｂ１ and the diameter of the columnar body 122 ｃ１ are different from each other. Furthermore, in this embodiment, the diameter of the columnar body 122 ｂ１ and the diameter of the columnar body 122 ｃ１ are such that the columnar body 122 ａ１ and the columnar body 122 ｂ１ and the columnar body 122 ｃ１The (average) diameter D of the multiple columnar bodies (fourth columnar body) 122 excluding the one above is different. Specifically, in this embodiment, for example, columnar body 122 ａ１ If the diameter is D, then the columnar body 122 ｂ１ Diameter D ｂ Let D be 0.85 × D, and columnar body 122 ｃ１ Diameter D ｃ This can be expressed as 0.72 × D.

[0078] As described above, in this embodiment, the opening 142 of the insulating layer 140 is positioned above the multiple defects 126 of the photonic crystal structure 120, which is the region that radiates light most directly forward. On the other hand, in this embodiment, the insulating layer 140 is positioned above the region of the photonic crystal structure 120 where the multiple defects 126 are not provided. In this embodiment, by providing the insulating layer 140 having the opening 142 that limits the region in which current flows, the region in which current flows preferentially is limited to the light-emitting layer 132 located above the region that radiates light most directly forward (resonator). As a result, according to this embodiment, the frontal radiation intensity of light can be increased while suppressing the power consumption of the light-emitting element 100.

[0079] In addition, in this embodiment, the multiple defects 126 are arranged so as to be separated from each other by three or more periods. According to this embodiment, by doing so, the band gap effect due to the periodic structure of the multiple columnar bodies 122 can be maintained, and light with a predetermined wavelength can be confined to the defects 126 and the region surrounding the defects 126.

[0080] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figures 3A, 3B, and 3C, but can take on various forms.

[0081] <<4. Second Embodiment>> Next, with reference to Figure 4, the detailed configuration of the photonic crystal structure 120 according to the second embodiment of the present disclosure will be described. Figure 4 is an enlarged view of a part of the photonic crystal structure 120 according to this embodiment, and corresponds to region C shown in Figure 3B. In the following description, only the differences from the first embodiment described above will be explained, and the points that are common to the first embodiment will not be explained.

[0082] In this embodiment as well, similar to the first embodiment, the opening 142 of the insulating layer 140 is positioned above the multiple defects 126 of the photonic crystal structure 120, which is the region that radiates light most directly forward. In this embodiment as well, the insulating layer 140 is positioned above the region of the photonic crystal structure 120 where the multiple defects 126 are not present. In this embodiment, by providing the insulating layer 140 having the opening 142 that limits the region in which current flows, the region in which current flows preferentially is limited to the light-emitting layer 132 located above the region that radiates light most directly forward (resonator). As a result, according to this embodiment, the frontal radiation intensity of light can be increased while suppressing the power consumption of the light-emitting element 100.

[0083] Furthermore, in this embodiment as well, as shown in Figure 4, there are multiple defects 126 ａ , 126 ｂ , 126 ｃ They are arranged so as to be separated from each other by three or more periods. According to this embodiment, by doing so, the band gap effect due to the periodic structure of the multiple columnar bodies 122 is maintained, and light of a predetermined wavelength is filtered into the defects 126 ａ , 126 ｂ , 126 ｃ And these can be confined to the surrounding areas.

[0084] In this embodiment as well, as shown in Figure 4, the unit unit is a defect 126 ａ Adjacent to it, defect 126 ａ Six columnar bodies (first columnar body) surrounding it 122 ａ１ And, defect 126 ｂ Adjacent to it, defect 126 ｂSix columnar bodies (second columnar bodies) surrounding it 122 ｂ１ And, defect 126 ｃ Adjacent to it, defect 126 ｃ Six columnar bodies (third columnar body) surrounding it 122 ｃ１ These columnar bodies 122 ａ１ , 122 ｂ１ , 122 ｃ１ As explained earlier, this is also called the "first period columnar body."

[0085] Furthermore, in this embodiment as well, columnar body 122 ａ１ The diameter and columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameters of the columnar bodies 122 are different from each other. ｂ１ The diameter and columnar body 122 ｃ１ The diameter of the columnar body 122 ａ１ and columnar body 122 ｂ１ and columnar body 122 ｃ１ The (average) diameter D of the multiple columnar bodies (fourth columnar body) 122 excluding the one above is different. Specifically, in this embodiment, for example, columnar body 122 ａ１ If the diameter is D, then the columnar body 122 ｂ１ Diameter D ｂ Let D be 0.85 × D, and columnar body 122 ｃ１ Diameter D ｃ This can be expressed as 0.72 × D.

[0086] Furthermore, in this embodiment, as shown in Figure 4, the unit unit is a columnar body 122 ａ１ Defect 126 ａ Twelve columnar bodies (the fifth columnar body) surrounding it 122 ｂ１ and columnar body 122 ｂ１ Defect 126 ｂ Twelve columnar bodies (the sixth columnar body) surrounding it 122 ｂ２ and columnar body 122 ｃ１ Defect 126 ｃ Twelve columnar bodies (the seventh columnar body) surrounding it 122 ｃ２ It has the following. In the following description, these columnar bodies 122 ａ２ , 122 ｂ２ , 122 ｃ２Each defect 126 is located through a single "first period columnar body" which includes ａ , 126 ｂ , 126 ｃ Multiple columnar bodies 122 surrounding the defect 126 ａ , 126 ｂ , 126 ｃ In relation to the columnar body 122, it is also referred to as the "second period columnar body". In other words, in this embodiment, the "second period columnar body" is the columnar body 122 ａ２ , 122 ｂ２ , 122 ｃ２ This includes the following. Furthermore, in this embodiment, there are columnar bodies 122 that are "first-period columnar bodies" for one defect 126 and "second-period columnar bodies" for other defects 126, and there are also columnar bodies 122 that are "second-period columnar bodies" for multiple defects 126.

[0087] Furthermore, in this embodiment, unlike the first embodiment, the center of the "first period columnar body" is each defect 126 ａ , 126 ｂ , 126 ｃ It is offset from a position at a period length a away from the center. In detail, columnar body 122 ａ１ The core issue is defect 126 ａ It is offset from a position at a period length a from the center, and the columnar body 122 ｂ１ The core issue is defect 126 ｂ It is offset from a position at a period length a from the center, and the columnar body 122 ｃ１ The core issue is defect 126 ｃ It is shifted from a position at a period length a away from the center. In other words, columnar body 122 ａ１ Center and columnar body 122 ｂ１ Center and columnar body 122 ｃ１ The center is offset from the position determined by the periodic arrangement of the columnar bodies 122.

[0088] Furthermore, in this embodiment, unlike the first embodiment, the center of the "second period columnar body" is each defect 126 ａ , 126 ｂ , 126 ｃ It is offset from a position at a distance of twice the period length a from the center. In detail, columnar body 122ａ２ The core issue is defect 126 ａ It is offset from a position at a distance of twice the period length a from the center, and the columnar body 122 ｂ２ The core issue is defect 126 ｂ It is offset from a position at a distance of twice the period length a from the center, and the columnar body 122 ｃ２ The core issue is defect 126 ｃ It is shifted from a position at a distance of twice the period length a from the center. In other words, columnar body 122 ａ２ Center and columnar body 122 ｂ２ Center and columnar body 122 ｃ２ The center is offset from the position determined by the periodic arrangement of the columnar bodies 122.

[0089] In other words, in this embodiment, the centers of the "first period columnar body" and the "second period columnar body" are offset from the positions determined by the periodic arrangement of the columnar bodies 122.

[0090] More specifically, in this embodiment, for example, the center of the "first periodic columnar body" may be moved by an additional 0.05 × a (shift amount) from the position determined by the periodic arrangement of the columnar bodies 122, away from the center of the corresponding defect 126. Furthermore, in this embodiment, for example, the center of the "second periodic columnar body" may be moved by an additional 0.2 × a (shift amount) from the position determined by the periodic arrangement of the columnar bodies 122, away from the center of the corresponding defect 126. In the above example, if a columnar body 122 is a "first periodic columnar body" for one defect 126 and a "second periodic columnar body" for other defects 126, and if a columnar body 122 is a "second periodic columnar body" for multiple defects 126, the shift amount and direction of movement are merged (vector sum) according to the above rules to move its center.

[0091] More specifically, in this embodiment, for example, columnar body 122 ａ１ The core issue is defect 126 ａ The columnar body 122 may be moved further outward by 0.05 × a (shift amount) from a position at a period length a from the center. ｂ１ The core issue is defect 126 ｂThe position may be moved further outward by 0.05 × a (shift amount) from a position a period length a away from the center. In addition, the columnar body 122 ｃ１ The core issue is defect 126 ｃ The position may be moved further outward by 0.05 × a (shift amount) from a position a period length a away from the center. Furthermore, in this embodiment, for example, the columnar body 122 ａ２ The core issue is defect 126 ａ The columnar body 122 may be moved further outward by 0.2a (shift amount) from a position that is twice the period length a from the center. ｂ１ The core issue is defect 126 ｂ The columnar body 122 may be further moved outward by 0.2a (shift amount) from a position that is twice the period length a from the center. ｃ１ The core issue is defect 126 ｃ The columnar body may be moved outward by a further 0.2a (shift amount) from a position twice the period length a from the center. Furthermore, in the above example, if the columnar body 122 is a "first period columnar body" for one defect 126 and a "second period columnar body" for other defects 126, and the columnar body 122 is a "second period columnar body" for multiple defects 126, the shift amount and direction of movement are merged (vector sum) according to the above rules to move its center.

[0092] As described above, in this embodiment as well, the opening 142 of the insulating layer 140 is positioned above the multiple defects 126 of the photonic crystal structure 120, which is the region that radiates light most directly forward. In this embodiment as well, the insulating layer 140 is positioned above the region of the photonic crystal structure 120 where the multiple defects 126 are not provided. In this embodiment, by providing the insulating layer 140 having the opening 142 that limits the region in which current flows, the region in which current flows preferentially is limited to the light-emitting layer 132 located above the region that radiates light most directly forward (resonator). As a result, according to this embodiment, the frontal radiation intensity of light can be increased while suppressing the power consumption of the light-emitting element 100.

[0093] In addition, in this embodiment as well, the multiple defects 126 are arranged so as to be separated from each other by three or more periods. According to this embodiment, by doing so, the band gap effect due to the periodic structure of the multiple columnar bodies 122 can be maintained, and light with a predetermined wavelength can be confined to the defects 126 and the region surrounding the defects 126.

[0094] In this embodiment, the photonic crystal structure 120 is not limited to the form shown in Figure 4, but can take on various forms. In this embodiment, it can also be modified as follows. For example, in Modification 1, similar to this embodiment, the columnar body 122 ａ１ The diameter and columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameters of the columnar bodies 122 are different from each other. ｂ１ The diameter and columnar body 122 ｃ１ The diameter of the columnar body 122 ａ１ and columnar body 122 ｂ１ and columnar body 122 ｃ１ The (average) diameter D of the multiple columnar bodies (the fourth columnar body) 122, excluding the one mentioned above, is different. Furthermore, in the modified example 1, the columnar body 122 ａ１ Center and columnar body 122 ｂ１ Center and columnar body 122 ｃ１ The center is offset from the position determined by the periodic arrangement of the columnar bodies 122. However, in Modification 1, unlike this embodiment, the columnar bodies 122 ａ２ Center and columnar body 122 ｂ２ Center and columnar body 122 ｃ２ The center does not necessarily have to be located at a position determined by the periodic arrangement of the columnar bodies 122.

[0095] Furthermore, in modification 2, for example, the columnar body 122 is the same as in this embodiment. ａ１ Center and columnar body 122 ｂ１ Center and columnar body 122 ｃ１ The center may be offset from the position determined by the periodic arrangement of the columnar bodies 122. However, in modified example 2, unlike this embodiment, the columnar bodies 122 ａ２ Center and columnar body 122 ｂ２ Center and columnar body 122ｃ２ The center does not have to be offset from the position determined by the periodic arrangement of the columnar bodies 122. Furthermore, in modified example 2, unlike this embodiment, the columnar bodies 122 ａ１ The diameter and columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameter may be the same as that of the columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameter of the columnar body 122 ｂ１ and columnar body 122 ｃ１ The (average) diameter D may be the same as that of the multiple columnar bodies (the fourth columnar body) 122 excluding the first one.

[0096] Furthermore, for example, in Modification 3, similar to this embodiment, the columnar body 122 ａ１ Center and columnar body 122 ｂ１ Center and columnar body 122 ｃ１ The center may be offset from the position determined by the periodic arrangement of the columnar bodies 122. Furthermore, in Modification 3, similar to this embodiment, the columnar bodies 122 ａ１ The diameter and columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameters of the columnar bodies 122 are different from each other. ｂ１ The diameter and columnar body 122 ｃ１ The diameter of the columnar body 122 ａ１ and columnar body 122 ｂ１ and columnar body 122 ｃ１ and columnar body 122 ａ２ and columnar body 122 ｂ２ and columnar body 122 ｃ２ The (average) diameter D of the multiple columnar bodies (the eighth columnar body) 122, excluding the one mentioned above, is different. In addition, in the modified example 3, the columnar body 122 ａ１ The diameter and columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameter and columnar body 122 ａ２ The diameter and columnar body 122 ｂ２ The diameter and columnar body 122 ｃ２ The diameters of the columnar bodies 122 are different from each other. ｂ１ The diameter and columnar body 122 ｃ１ The diameter and columnar body 122 ａ２ The diameter and columnar body 122 ｂ２ The diameter and columnar body 122ｃ２ The diameter of the columnar body 122 ａ１ and columnar body 122 ｂ１ and columnar body 122 ｃ１ and columnar body 122 ａ２ and columnar body 122 ｂ２ and columnar body 122 ｃ２ The (average) diameter D of the multiple columnar bodies (the eighth columnar body) 122, excluding the one mentioned above, may be different.

[0097] Furthermore, in modification 4, for example, in addition to the embodiment, a columnar body 122 ａ１ The diameter and columnar body 122 ｂ１ The diameter and columnar body 122 ｃ１ The diameter and columnar body 122 ａ２ The diameter and columnar body 122 ｂ２ The diameter and columnar body 122 ｃ２ The diameters of the columnar bodies 122 are different from each other. ｂ１ The diameter and columnar body 122 ｃ１ The diameter and columnar body 122 ａ２ The diameter and columnar body 122 ｂ２ The diameter and columnar body 122 ｃ２ The diameter of the columnar body 122 ａ１ and columnar body 122 ｂ１ and columnar body 122 ｃ１ and columnar body 122 ａ２ and columnar body 122 ｂ２ and columnar body 122 ｃ２ The (average) diameter D of the multiple columnar bodies (the eighth columnar body) 122, excluding the one mentioned above, may be different.

[0098] <<5. Third Embodiment>> Next, with reference to Figure 5, the detailed configuration of the light-emitting element 100 according to the third embodiment of the present disclosure will be described. Figure 5 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to the present embodiment.

[0099] As shown in Figure 5, the light-emitting element 100 according to this embodiment has a laminated structure in which a photonic crystal structure 120, a lower electrode 130, a light-emitting layer 132, an insulating layer 140, an upper electrode 134, and a protective film 150 are sequentially stacked on a substrate 110, similar to the first embodiment. Furthermore, as shown in Figure 5, the light-emitting element 100 according to this embodiment has an on-chip lens 160 on the protective film 150. In the following description, only the on-chip lens 160, which differs from the first embodiment described above, will be explained, and the points common to the first and second embodiments will not be explained.

[0100] The on-chip lens 160 can be formed from polymethyl methacrylate (refractive index 1.37). Furthermore, in this embodiment, as shown in Figure 5, the principal ray 190 of the on-chip lens 160 has a lens shape such that it passes through the opening 142 of the insulating layer 140. Such an on-chip lens 160 can efficiently guide light from the multiple defects 126, which are the most light-emitting regions, and the surrounding regions to the upper front of the light-emitting element 100.

[0101] As described above, in this embodiment, by providing such an on-chip lens 160, the light whose intensity has been increased by the resonator of the photonic crystal structure 120 can be efficiently guided to the upper front of the light-emitting element 100. Therefore, according to this embodiment, the frontal radiation intensity of the light can be increased while suppressing the power consumption of the light-emitting element 100.

[0102] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 5, but can take on various forms. For example, in this embodiment, the photonic crystal structure 120 according to the first embodiment, as shown in Figures 3B and 3C, may be applied, or the photonic crystal structure 120 according to the second embodiment, as shown in Figure 4, may be applied.

[0103] <<6. Fourth Embodiment>> Next, the detailed configuration of the display panel 40 according to the fourth embodiment of the present disclosure will be described with reference to Figures 6A and 6B. Figures 6A and 6B are schematic diagrams showing an example of the cross-sectional configuration of the display panel 40 according to this embodiment. In the following description, only the differences from the first embodiment described above will be explained, and the points common to the first to third embodiments will not be explained.

[0104] In this embodiment, as shown in Figure 6A, the light-emitting elements 100 are arranged on the display panel 40. More specifically, in this embodiment, as shown in Figure 6B which shows the arrangement of the photonic crystal structures 120 on the display panel 40, the photonic crystal structures 120 of each hexagonal light-emitting element 100 can be arranged in a delta configuration (each photonic crystal structure 120 is positioned at the vertices of a triangle). Furthermore, in this embodiment, adjacent light-emitting elements 100 are separated by a boundary portion 170. The boundary portion 170 can be formed from, for example, an inorganic insulating material such as silicon oxide, silicon nitride, or silicon oxynitride.

[0105] In this embodiment, the display panel 40 is not limited to the form shown in Figures 6A and 6B, but can take on various forms. For example, in this embodiment, the photonic crystal structure 120 according to the first embodiment, as shown in Figures 3B and 3C, may be applied, or the photonic crystal structure 120 according to the second embodiment, as shown in Figure 4, may be applied.

[0106] <<7. Summary>> As described above, in each embodiment of the present disclosure, the opening 142 of the insulating layer 140 is provided so as to be located above a plurality of defects 126 of the photonic crystal structure 120, which is the region that radiates light most directly forward. On the other hand, the insulating layer 140 is provided so as to be located above a region of the photonic crystal structure 120 where the plurality of defects 126 are not provided. In each embodiment of the present disclosure, by providing the insulating layer 140 having the opening 142 that limits the region in which current flows, the region in which current flows preferentially is limited to the light-emitting layer 132 located above the region that radiates light most directly forward (resonator). As a result, according to each embodiment of the present disclosure, the frontal radiation intensity of light can be increased while suppressing the power consumption of the light-emitting element 100.

[0107] In addition, in each embodiment of the present disclosure, the plurality of defects 126 are arranged so as to be separated from each other by three or more periods. According to each embodiment of the present disclosure, this maintains the bandgap effect due to the periodic structure of the plurality of columnar bodies 122, and makes it possible to confine light of a predetermined wavelength to the defects 126 and the region surrounding the defects 126.

[0108] Furthermore, the display device 10 according to the embodiment of this disclosure can be applied to, for example, VR, MR, or AR display devices, smartphones, television devices, electronic viewfinders (EVFs), or small projectors. In addition, the display device 10 can also be applied to various lighting devices.

[0109] Furthermore, the light-emitting element 100 according to the embodiment of this disclosure can be manufactured using methods, apparatus, and conditions commonly used in the manufacture of semiconductor devices. In other words, the light-emitting element 100 according to this embodiment can be manufactured using existing semiconductor device manufacturing methods.

[0110] Examples of the methods mentioned above include the PVD (Physical Vapor Deposition) method, the CVD (Chemical Vapor Deposition) method, and the ALD (Atomic Layer Deposition) method. Examples of PVD methods include vacuum deposition, electron beam (EB) deposition, various sputtering methods (magnetron sputtering, RF (Radio Frequency)-DC (Direct Current) coupled bias sputtering, ECR (Electron Cyclotron Resonance) sputtering, counter-target sputtering, high-frequency sputtering, etc.), ion plating, laser ablation, molecular beam epitaxy (MBE (Molecular Beam Epitaxy)), and laser transfer. Examples of CVD methods include plasma CVD, thermal CVD, metal-organic (MO) CVD, and optical CVD. Furthermore, other methods include electrolytic plating, electroless plating, spin coating, immersion, casting, microcontact printing, drop casting, various printing methods such as screen printing, inkjet printing, offset printing, gravure printing, and flexographic printing, as well as stamping, spraying, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, transfer roll coater, gravure coater, kiss coater, cast coater, spray coater, slit orifice coater, and calender coater. In addition, patterning methods include chemical etching such as shadow masks, laser transfer, and photolithography, as well as physical etching using ultraviolet light or lasers. Furthermore, planarization techniques include CMP (Chemical Mechanical Polishing), laser planarization, and reflow.

[0111] <<8. Modifications>> <8.1 Modification 1> Next, as a modification of the embodiment of the present disclosure, a modification concerning the relationship between the normal LN passing through the center of the light-emitting element 100, the normal LN' passing through the center of the lens structure (for example, the on-chip lens 160 provided on the light-emitting element 100), and the normal LN" passing through the center of the wavelength selection unit (for example, the color filter provided on the light-emitting element 100) will be described with reference to Figures 7A to 7G. Figures 7A to 7G are conceptual diagrams for explaining the relationship between the normal LN passing through the center of the light-emitting unit, the normal LN' passing through the center of the lens member, and the normal LN" passing through the center of the wavelength selection unit. In the following description, the center of the light-emitting element 100 will be referred to as the center of the light-emitting unit.

[0112] In embodiments of this disclosure, the size of the wavelength selection area may be appropriately changed in accordance with the light emitted by the light-emitting element 100. Furthermore, if a light-absorbing layer (black matrix layer) is provided between the wavelength selection area of ​​an adjacent light-emitting element 100, the size of the light-absorbing layer (black matrix layer) may be appropriately changed in accordance with the light emitted by the light-emitting element 100. In addition, the size of the wavelength selection area may be determined by the distance (offset amount) d between the normal passing through the center of the light-emitting element 100 and the normal passing through the center of the wavelength selection area. ０ Depending on the circumstances, it may be changed as appropriate. The planar shape of the wavelength selection section may be the same as, similar to, or different from the planar shape of the lens element.

[0113] For example, as shown in Figure 7A, the normal vector LN passing through the center of the light-emitting part, the normal vector LN'' passing through the center of the wavelength selection part, and the normal vector LN' passing through the center of the lens member may be made to coincide. In other words, the distance (offset amount) D between the normal vector passing through the center of the light-emitting part and the normal vector passing through the center of the lens member. ０ The distance (offset amount) d between the normal vector passing through the center of the light-emitting part and the normal vector passing through the center of the wavelength-selecting part. ０ This is equivalent to 0 (zero).

[0114] Furthermore, as shown in Figure 7B, for example, the normal vector LN passing through the center of the light-emitting part and the normal vector LN'' passing through the center of the wavelength-selecting part coincide, but the normal vector LN passing through the center of the light-emitting part and the normal vector LN'' passing through the center of the wavelength-selecting part do not have to coincide with the normal vector LN' passing through the center of the lens member. In other words, D ０ ≠d ０ It may also be equal to 0.

[0115] Furthermore, for example, as shown in Figure 7C, the normal vector LN passing through the center of the light-emitting part, the normal vector LN'' passing through the center of the wavelength-selecting part, and the normal vector LN' passing through the center of the lens member do not coincide, but the normal vector LN'' passing through the center of the wavelength-selecting part and the normal vector LN' passing through the center of the lens member may coincide. In other words, D ０ = d ０ It can also be 0.

[0116] Furthermore, as shown in Figure 7D, for example, the normal vector LN passing through the center of the light-emitting part, the normal vector LN'' passing through the center of the wavelength-selecting part, and the normal vector LN' passing through the center of the lens member do not coincide, and the normal vector LN' passing through the center of the lens member does not coincide with the normal vector LN passing through the center of the surface of the light-emitting part and the normal vector LN'' passing through the center of the wavelength-selecting part. Here, it is preferable that the center of the wavelength-selecting part (shown as a black circle in Figure 7D) is located on a straight line LL connecting the center of the surface of the light-emitting part and the center of the lens member (shown as a black circle in Figure 7D). Specifically, the distance from the center of the surface of the light-emitting part in the thickness direction to the center of the wavelength-selecting part is LL. １ The distance from the center of the wavelength selection area in the thickness direction to the center of the lens material is LL ２ In that case, D ０ >d ０ > 0, and considering manufacturing variations, d ０ : D ０ =LL １ : (LL １ +LL ２ It is preferable that the following conditions be satisfied.

[0117] Furthermore, the stacking relationship between the wavelength selection unit and the lens member may be reversed. In such a case, for example, as shown in Figure 7E, the normal vector LN passing through the center of the light-emitting unit, the normal vector LN'' passing through the center of the wavelength selection unit, and the normal vector LN' passing through the center of the lens member may be made to coincide. In other words, D ０ = d ０ It may also be equal to 0.

[0118] Furthermore, for example, as shown in Figure 7F, the normal vector LN passing through the center of the light-emitting part, the normal vector LN'' passing through the center of the wavelength-selecting part, and the normal vector LN' passing through the center of the lens member do not coincide, but the normal vector LN'' passing through the center of the wavelength-selecting part and the normal vector LN' passing through the center of the lens member may coincide. In other words, D ０ = d ０ It can also be 0.

[0119] Furthermore, as shown in the conceptual diagram Figure 7G, the normal vector LN passing through the center of the surface of the light-emitting part, the normal vector LN'' passing through the center of the wavelength-selecting part, and the normal vector LN' passing through the center of the lens member do not coincide, and the normal vector LN' passing through the center of the lens member does not coincide with the normal vector LN passing through the center of the surface of the light-emitting part and the normal vector LN'' passing through the center of the wavelength-selecting part. Here, it is preferable that the center of the wavelength-selecting part is located on the straight line LL connecting the center of the surface of the light-emitting part and the center of the lens member. Specifically, the distance from the center of the surface of the light-emitting part in the thickness direction to the center of the wavelength-selecting part (shown as a black circle in Figure 7G) is LL. １ The distance from the center of the wavelength selection area in the thickness direction to the center of the lens member (shown as a black circle in Figure 7G) is LL ２ When that happens, d ０ >D ０ > 0, and considering manufacturing variations, D ０ :d ０ =LL ２ : (LL １ +LL ２ It is preferable that the following conditions be satisfied.

[0120] <8.2 Modification 2> The subpixel 1100 (more specifically, the light-emitting element 100) used in the display device 10 according to the embodiment of the present disclosure described above may be configured to include a resonator structure (microcavity structure) that resonates the light generated in the light-emitting layer 132. The above resonator structure will be described below with reference to Figures 8 to 14. Figure 8 is a schematic cross-sectional view illustrating a first example of the resonator structure, Figure 9 is a schematic cross-sectional view illustrating a second example of the resonator structure, and Figure 10 is a schematic cross-sectional view illustrating a third example of the resonator structure. Furthermore, Figure 11 is a schematic cross-sectional view illustrating a fourth example of the resonator structure, and Figure 12 is a schematic cross-sectional view illustrating a fifth example of the resonator structure. Furthermore, Figure 13 is a schematic cross-sectional view illustrating a sixth example of the resonator structure, and Figure 14 is a schematic cross-sectional view illustrating a seventh example of the resonator structure. In these diagrams, the letters attached to each symbol indicate the corresponding color; specifically, "B" represents blue, "G" represents green, and "R" represents red.

[0121] (Resonator structure: First example) Figure 8 is a schematic cross-sectional view illustrating the first example of a resonator structure. In the first example, the first electrode (specifically, the lower electrode 130) 1202 is formed with a common film thickness in each subpixel 1100. The same applies to the second electrode (specifically, the upper electrode 134) 1206.

[0122] As shown in Figure 8, a reflector 1401 is positioned below the first electrode 1202 of the subpixel 1100, with an optical adjustment layer 1402 in between. A resonator structure is formed between the reflector 1401 and the second electrode 1206, causing the light generated by the organic layer (specifically, the light-emitting layer 132) 1204 to resonate.

[0123] The reflector 1401 is formed with a common film thickness for each subpixel 1100. The film thickness of the optical adjustment layer 1402 differs depending on the color that the subpixel 1100 is to display. By having optical adjustment layers 1402R, 1402G, and 1402B with different film thicknesses, it is possible to set the optical distance that produces the optimal resonance for the wavelength of light corresponding to the color to be displayed.

[0124] In the example shown in Figure 8, the upper surfaces of the reflectors 1401 for subpixels 1100R, 1100G, and 1100B are aligned. As described above, the thickness of the optical adjustment layer 1402 differs depending on the color that the subpixel 1100 should display, so the position of the upper surface of the second electrode 1206 differs depending on the type of subpixel 1100R, 1100G, and 1100B.

[0125] The reflector 1401 can be formed using, for example, a metal such as aluminum (Al), silver (Ag), or copper (Cu), or an alloy mainly composed of these metals.

[0126] The optical adjustment layer 1402 can be constructed using inorganic insulating materials such as silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiOxNy), or organic resin materials such as acrylic resin or polyimide resin. The optical adjustment layer 1402 may be a single layer or a laminated film of multiple materials. Furthermore, the number of layers may vary depending on the type of subpixel 1100.

[0127] The first electrode 1202 can be formed using a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO).

[0128] The second electrode 1206 preferably functions as a semi-transparent reflective film. The second electrode 1206 can be formed using magnesium (Mg), silver (Ag), or a magnesium-silver alloy (MgAg) mainly composed of these, or an alloy containing alkali metals or alkaline earth metals.

[0129] (Resonator structure: Second example) Figure 9 is a schematic cross-sectional view illustrating a second example of the resonator structure. In this second example as well, the first electrode 1202 and the second electrode 1206 are formed with a common film thickness in each subpixel 1100.

[0130] In the second example as well, a reflector 1401 is placed beneath the first electrode 1202 of the subpixel 1100, with an optical adjustment layer 1402 in between. A resonator structure is formed between the reflector 1401 and the second electrode 1206 to resonate the light generated by the organic layer 1204. Similar to the first example, the reflector 1401 is formed with a common film thickness for each subpixel 1100, while the film thickness of the optical adjustment layer 1402 differs according to the color that the subpixel 1100 should display.

[0131] In the first example shown in Figure 8, the upper surfaces of the reflectors 1401 for subpixels 1100R, 1100G, and 1100B were aligned, while the position of the upper surface of the second electrode 1206 differed depending on the type of subpixel 1100R, 1100G, and 1100B.

[0132] In contrast, in the second example shown in Figure 9, the upper surface of the second electrode 1206 is arranged to align with the subpixels 1100R, 1100G, and 1100B. In order to align the upper surfaces of the second electrode 1206, the upper surface of the reflector 1401 is arranged differently for the subpixels 1100R, 1100G, and 1100B, depending on the type of subpixel. As a result, the lower surface of the reflector 1401 has a stepped shape depending on the type of subpixel 1100R, 1100G, and 1100B.

[0133] The materials and other components constituting the reflector 1401, the optical adjustment layer 1402, the first electrode 1202, and the second electrode 1206 are the same as those described in the first example, so their explanation will be omitted.

[0134] (Resonator structure: Third example) Figure 10 is a schematic cross-sectional view illustrating the third example of the resonator structure. In the third example as well, the first electrode 1202 and the second electrode 1206 are formed with a common film thickness in each subpixel 1100.

[0135] In the third example, the reflector 1401 is positioned below the first electrode 1202 of the subpixel 1100, with the optical adjustment layer 1402 in between. A resonator structure is formed between the reflector 1401 and the second electrode 1206 to resonate the light generated by the organic layer 1204. Similar to the first and second examples, the thickness of the optical adjustment layer 1402 varies depending on the color that the subpixel 1100 should display. And, similar to the second example, the upper surface of the second electrode 1206 is positioned so that it aligns with the subpixels 1100R, 1100G, and 1100B.

[0136] In the second example shown in Figure 9, the lower surface of the reflector 1401 had a stepped shape corresponding to the type of sub-pixel 1100R, 1100G, and 1100B in order to align the upper surface of the second electrode 1206.

[0137] In contrast, in the third example shown in Figure 10, the film thickness of the reflector 1401 is set to differ depending on the type of sub-pixel 1100R, 1100G, and 1100B. More specifically, the film thickness is set so that the lower surfaces of the reflectors 1401R, 1401G, and 1401B are aligned.

[0138] The materials constituting the reflector 1401, the optical adjustment layer 1402, the first electrode 1202, and the second electrode 1206 are the same as those described in the first example, so their explanation will be omitted.

[0139] (Resonator structure: 4th example) Figure 11 is a schematic cross-sectional view illustrating the 4th example of a resonator structure.

[0140] In the first example shown in Figure 8, the first electrode 1202 and the second electrode 1206 of the subpixel 1100 are formed with a common film thickness. A reflector 1401 is placed below the first electrode 1202 of the subpixel 1100, with an optical adjustment layer 1402 in between.

[0141] In contrast, in the fourth example shown in Figure 11, the optical adjustment layer 1402 is omitted, and the film thickness of the first electrode 1202 is set to differ depending on the type of subpixel 1100R, 1100G, and 1100B.

[0142] The reflector 1401 is formed with a common film thickness for each subpixel 1100. The film thickness of the first electrode 1202 differs depending on the color that the subpixel 1100 is to display. By having the first electrodes 1202R, 1202G, and 1202B have different film thicknesses, it is possible to set the optical distance that produces the optimal resonance for the wavelength of light corresponding to the color to be displayed.

[0143] The materials constituting the reflector 1401, the first electrode 1202, and the second electrode 1206 are the same as those described in the first example, so their explanation will be omitted.

[0144] (Resonator structure: Fifth example) Figure 12 is a schematic cross-sectional view illustrating the fifth example of a resonator structure.

[0145] In the first example shown in Figure 8, the first electrode 1202 and the second electrode 1206 are formed with a common film thickness in each subpixel 1100. A reflector 1401 is placed below the first electrode 1202 of the subpixel 1100, with an optical adjustment layer 1402 in between.

[0146] In contrast, in the fifth example shown in Figure 12, the optical adjustment layer 1402 was omitted, and instead, an oxide film 1404 was formed on the surface of the reflector 1401. The thickness of the oxide film 1404 was set to differ depending on the type of subpixel 1100R, 1100G, and 1100B.

[0147] The thickness of the oxide film 1404 varies depending on the color that the subpixel 1100 is to display. By having oxide films 1404R, 1404G, and 1404B with different thicknesses, it is possible to set the optical distance that produces the optimal resonance for the wavelength of light corresponding to the color to be displayed.

[0148] The oxide film 1404 is a film obtained by oxidizing the surface of the reflector 1401, and is composed of, for example, aluminum oxide, tantalum oxide, titanium oxide, magnesium oxide, zirconium oxide, etc. The oxide film 1404 functions as an insulating film for adjusting the optical path length (optical distance) between the reflector 1401 and the second electrode 1206.

[0149] The oxide film 1404, which has a different thickness depending on the type of subpixel 1100R, 1100G, and 1100B, can be formed, for example, as follows.

[0150] First, the container is filled with electrolyte, and the substrate on which the reflector 1401 is formed is immersed in the electrolyte. Then, electrodes are positioned opposite the reflector 1401.

[0151] Then, a positive voltage is applied to the reflector 1401 with the electrode as the reference, and the reflector 1401 is anodized. The thickness of the oxide film formed by anodization is proportional to the voltage value applied to the electrode. Therefore, anodization is performed on each of the reflectors 1401R, 1401G, and 1401B with a voltage corresponding to the type of sub-pixel 1100R, 1100G, and 1100B applied. This makes it possible to form oxide films 1404 of different thicknesses all at once.

[0152] The materials constituting the reflector 1401, the first electrode 1202, and the second electrode 1206 are the same as those described in the first example, so their explanation will be omitted.

[0153] (Resonator Structure: Sixth Example) Figure 13 is a schematic cross-sectional view illustrating the sixth example of a resonator structure. In the sixth example, the subpixel 1100 is constructed by stacking a first electrode 1202, an organic layer 1204, and a second electrode 1206. However, in the sixth example, the first electrode 1202 is formed to serve both as an electrode and a reflector. The first electrode (and reflector) 1202 is made of a material having optical constants selected according to the type of subpixel 1100R, 1100G, and 1100B. By different phase shifts caused by the first electrode (and reflector) 1202, it is possible to set an optical distance that produces optimal resonance for the wavelength of light corresponding to the color to be displayed.

[0154] The first electrode (and reflector) 1202 can be made from a single metal such as aluminum (Al), silver (Ag), gold (Au), or copper (Cu), or from an alloy mainly composed of these metals. For example, the first electrode (and reflector) 1202R of the subpixel 1100R can be made of copper (Cu), and the first electrode (and reflector) 1202G of the subpixel 1100G and the first electrode (and reflector) 1202B of the subpixel 1100B can be made of aluminum.

[0155] The materials and other components constituting the second electrode 1206 are the same as those described in the first example, so we will omit further explanation.

[0156] (Resonator Structure: Seventh Example) Figure 14 is a schematic cross-sectional view illustrating the seventh example of the resonator structure. The seventh example basically applies the sixth example to subpixels 1100R and 1100G, and the first example to subpixel 1100B. In this configuration as well, it is possible to set the optical distance that produces optimal resonance for the wavelength of light corresponding to the color to be displayed.

[0157] The first electrodes (which also serve as reflectors) 1202R and 1202G used in the sub-pixels 1100R and 1100G can be made from elemental metals such as aluminum (Al), silver (Ag), gold (Au), and copper (Cu), or alloys in which these metals are the main components.

[0158] The materials constituting the reflector 1401B, optical adjustment layer 1402B, and first electrode 1202B used in the subpixel 1100B are the same as those described in the first example, so their explanation will be omitted.

[0159] <<9. Examples of Application>> For example, the technology relating to this disclosure may be applied to the display units of various electronic devices. Therefore, examples of electronic devices to which this technology can be applied will be described below.

[0160] (Specific Example 1) Figure 15A is a front view showing an example of the external appearance of the digital still camera 500, and Figure 15B is a rear view showing an example of the external appearance of the digital still camera 500. This digital still camera 500 is a single-lens reflex type with interchangeable lenses, and has an interchangeable shooting lens unit (interchangeable lens) 512 located approximately in the center of the front of the camera body 511, and a grip portion 513 for the photographer to hold on the left side of the front.

[0161] A monitor 514 is provided on the back of the camera body 511, slightly to the left of the center. An electronic viewfinder (eyepiece) 515 is provided above the monitor 514. The photographer can determine the composition by looking through the electronic viewfinder 515 and visually confirming the light image of the subject guided by the shooting lens unit 512. The display device 10 according to the embodiment of this disclosure can be used as the monitor 514 and the electronic viewfinder 515.

[0162] (Specific Example 2) Figure 16 is an external view of a head-mounted display 600. The head-mounted display 600 has, for example, an eyeglass-shaped display unit 611 and ear hooks 612 on both sides for attachment to the user's head. In this head-mounted display 600, the display device 10 according to the embodiment of this disclosure can be used as the display unit 611.

[0163] (Specific Example 3) Figure 17 is an external view of the see-through head-mounted display 634. The see-through head-mounted display 634 consists of a main body 632, an arm 633, and a lens barrel 631.

[0164] The main body 632 is connected to the arm 633 and the eyeglasses 630. Specifically, the long end of the main body 632 is connected to the arm 633, and one side of the main body 632 is connected to the eyeglasses 630 via a connecting member. The main body 632 may also be directly attached to the head of a person.

[0165] The main body 632 houses a control board for controlling the operation of the see-through head-mounted display 634 and a display unit. The arm 633 connects the main body 632 to the lens barrel 631 and supports the lens barrel 631. Specifically, the arm 633 is connected to the end of the main body 632 and the end of the lens barrel 631, respectively, and fixes the lens barrel 631 in place. The arm 633 also houses signal lines for communicating image-related data provided from the main body 632 to the lens barrel 631.

[0166] The lens barrel 631 projects image light, provided from the main body 632 via the arm 633, through the eyepiece lens towards the eyes of the user wearing the see-through head-mounted display 634. In this see-through head-mounted display 634, the display device 10 according to the embodiment of this disclosure can be used in the display section of the main body 632.

[0167] (Specific Example 4) Figure 18 shows an example of the appearance of a television device 710. This television device 710 has, for example, a video display screen section 711 including a front panel 712 and a filter glass 713, and this video display screen section 711 is configured by a display device 10 according to the embodiment of this disclosure.

[0168] (Specific Example 5) Figure 19 shows an example of the appearance of a smartphone 800. The smartphone 800 has a display unit 802 that displays various information, and an operation unit consisting of buttons, etc. that accept user input. The display unit 802 may be the display device 10 according to this embodiment.

[0169] (Specific Example 6) Figures 20A and 20B show the internal configuration of an automobile having a display device 10 according to the embodiment of this disclosure as a display device. More specifically, Figure 20A shows the interior of the automobile from the rear to the front, and Figure 20B shows the interior of the automobile from the diagonally rear to the diagonally front.

[0170] The automobile shown in Figures 20A and 20B includes a center display 911, a console display 912, a head-up display 913, a digital rear mirror 914, a steering wheel display 915, and a rear entertainment display 916. Some or all of these displays can be fitted with the display device 10 according to the embodiment of this disclosure.

[0171] The center display 911 is positioned on the center console 907, facing the driver's seat 901 and the passenger seat 902. Figures 26A and 26B show an example of a horizontally elongated center display 911 extending from the driver's seat 901 to the passenger seat 902, but the screen size and placement of the center display 911 are arbitrary. The center display 911 can display information detected by various sensors (not shown). As a specific example, the center display 911 can display images captured by an image sensor, distance images to obstacles in front of or to the side of the vehicle measured by a ToF (Time of Flight) sensor, and the body temperature of passengers detected by an infrared sensor. The center display 911 can be used to display, for example, at least one of safety-related information, operation-related information, life logs, health-related information, authentication / identification-related information, and entertainment-related information.

[0172] Safety-related information includes information such as drowsiness detection, distraction detection, detection of mischief by a passenger, seatbelt fastening status, and detection of an unattended occupant. This information is detected, for example, by a sensor (not shown) placed on top of the back of the center display 1911. Operation-related information is detected by sensing occupant gestures using sensors. The detected gestures may include the operation of various equipment in the vehicle. For example, the sensor detects the operation of air conditioning equipment, navigation systems, AV (Audio / Visual) systems, lighting systems, etc. Life logs include the life logs of all occupants. For example, life logs include records of each occupant's actions while riding in the vehicle. By acquiring and saving life logs, it is possible to confirm the state of the occupants at the time of an accident. Health-related information is detected by sensing the occupant's body temperature using a temperature sensor and inferring the occupant's health status based on the detected body temperature. Alternatively, the occupant's face may be captured using an image sensor, and the occupant's health status may be inferred from the facial expression captured. Furthermore, the system may engage in automated voice conversations with the occupants and infer their health status based on their responses. Authentication / identification-related information includes keyless entry functions that use sensors for facial recognition and functions that automatically adjust seat height and position based on facial recognition. Entertainment-related information includes functions that use sensors to detect information on how the occupants operate the AV equipment and functions that use sensors to recognize the occupants' faces and provide content suitable for the occupants through the AV equipment.

[0173] The console display 912 can be used, for example, to display life log information. The console display 912 is located near the shift lever 908 on the center console 907 between the driver's seat 901 and the passenger seat 902. The console display 912 can also display information detected by various sensors (not shown). In addition, the console display 912 may display an image of the area around the vehicle captured by an image sensor, or it may display an image showing the distance to obstacles around the vehicle.

[0174] The head-up display 913 is virtually displayed behind the windshield 904 in front of the driver's seat 901. The head-up display 913 can be used to display at least one of the following: safety-related information, operation-related information, life logs, health-related information, authentication / identification-related information, and entertainment-related information. Because the head-up display 913 is often virtually positioned in front of the driver's seat 901, it is suitable for displaying information directly related to the operation of the vehicle, such as the vehicle's speed and fuel (battery) level.

[0175] The digital rearview mirror 914 can not only display what is behind the vehicle, but also what is happening to the passengers in the rear seat. By placing a sensor (not shown) on top of the back of the digital rearview mirror 914, it can be used, for example, to display life log information.

[0176] The steering wheel display 915 is positioned near the center of the steering wheel 906 of the automobile. The steering wheel display 915 can be used to display at least one of the following: safety-related information, operation-related information, life log, health-related information, authentication / identification-related information, and entertainment-related information. In particular, because the steering wheel display 915 is located near the driver's hands, it is suitable for displaying life log information such as the driver's body temperature, or information related to the operation of AV equipment, air conditioning equipment, etc.

[0177] The rear entertainment display 916 is mounted on the back of the driver's seat 901 and the passenger seat 902, and is intended for viewing by rear-seat passengers. The rear entertainment display 916 can be used to display at least one of the following: safety-related information, operation-related information, life logs, health-related information, authentication / identification-related information, and entertainment-related information. In particular, because the rear entertainment display 916 is in front of the rear-seat passengers, it displays information relevant to the rear-seat passengers. For example, it may display information related to the operation of AV equipment or air conditioning equipment, or it may display the results of measurements of the rear-seat passengers' body temperature, etc., taken by a temperature sensor (not shown).

[0178] <<10. Supplementary Information>> Although preferred embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person with ordinary skill in the art of the present disclosure may conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and these will naturally also fall within the technical scope of the present disclosure.

[0179] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that will be apparent to those skilled in the art from the description herein, in addition to or in lieu of the effects described herein.

[0180] Furthermore, this technology can also be configured as follows. (1) A display device having a plurality of light-emitting elements arranged on a substrate, wherein each light-emitting element comprises: an emitting layer; a first electrode and a second electrode sandwiching the emitting layer from above and below; a photonic crystal structure provided so as to face the emitting layer with the second electrode in between; and an insulating layer provided between the first electrode and the emitting layer, having an opening on the center of the photonic crystal structure, wherein the photonic crystal structure comprises: a plurality of columnar bodies arranged periodically with a predetermined period length in a first region overlapping the opening and a second region not overlapping the opening; and a plurality of defects provided in the first region so as to be separated from each other for three or more periods, which disrupt the period of the arrangement of the plurality of columnar bodies, wherein the first region of the photonic crystal structure is divided into a plurality of unit units, the plurality of unit units are arranged at positions that are n (an integer of 2 or more) rotationally symmetric with respect to the center of the photonic crystal structure as the rotational center, and each unit unit has the defects in at least three locations, the display device. (2) The display device according to (1) above, wherein each unit has a first defect located at the center of the photonic crystal structure, a second defect and a third defect, and the plurality of columnar bodies include a plurality of first columnar bodies adjacent to and surrounding the first defect, a plurality of second columnar bodies adjacent to and surrounding the second defect, a plurality of third columnar bodies adjacent to and surrounding the third defect, and a plurality of fourth columnar bodies other than the first, second and third columnar bodies, wherein the diameters of the first columnar bodies, the diameters of the second columnar bodies and the diameters of the third columnar bodies are different from each other, and the diameters of the second and third columnar bodies are different from the average value of the diameters of the fourth columnar body. (3) The display device according to (2) above, wherein the center of the first columnar body is offset from a position a predetermined period length away from the center of the first defect, the center of the second columnar body is offset from a position a predetermined period length away from the center of the second defect, and the center of the third columnar body is offset from a position a predetermined period length away from the center of the third defect.(4) The display device according to (3) above, wherein the plurality of columnar bodies further include: a plurality of fifth columnar bodies surrounding the first defect via the first columnar bodies; a plurality of sixth columnar bodies surrounding the second defect via the second columnar bodies; and a plurality of seventh columnar bodies surrounding the third defect via the third columnar bodies, wherein the center of the fifth columnar body is offset from a position at a distance of twice the predetermined period length from the center of the first defect; the center of the sixth columnar body is offset from a position at a distance of twice the predetermined period length from the center of the second defect; and the center of the seventh columnar body is offset from a position at a distance of twice the predetermined period length from the center of the third defect. (5) The display device according to (1) above, wherein each unit has a first defect located at the center of the photonic crystal structure, a second defect and a third defect, and the plurality of columnar bodies include a plurality of first columnar bodies adjacent to and surrounding the first defect, a plurality of second columnar bodies adjacent to and surrounding the second defect, and a plurality of third columnar bodies adjacent to and surrounding the third defect, the center of the first columnar body is offset from a position a predetermined period length away from the center of the first defect, the center of the second columnar body is offset from a position a predetermined period length away from the center of the second defect, and the center of the third columnar body is offset from a position a predetermined period length away from the center of the third defect. (6) The display device according to (5) above, wherein the plurality of columnar bodies further include: a plurality of fifth columnar bodies surrounding the first defect via the first columnar body; a plurality of sixth columnar bodies surrounding the second defect via the second columnar body; a plurality of seventh columnar bodies surrounding the third defect via the third columnar body; and a plurality of eighth columnar bodies other than the first, second, third, fifth, sixth, and seventh columnar bodies, wherein the first, second, third, fifth, sixth, and seventh columnar bodies have different diameters from each other, and the diameters of the second, third, fifth, sixth, and seventh columnar bodies are different from the average value of the diameters of the eighth columnar body.(7) The display device according to (6), wherein the center of the fifth columnar body is offset from a position at a distance of twice the predetermined period length from the center of the first defect, the center of the sixth columnar body is offset from a position at a distance of twice the predetermined period length from the center of the second defect, and the center of the seventh columnar body is offset from a position at a distance of twice the predetermined period length from the center of the third defect. (8) The display device according to any one of (1) to (7), wherein the plurality of unit units are regularly arranged to surround the center of the photonic crystal structure. (9) The display device according to (2) or (5), wherein the plurality of columnar bodies are arranged in four or more periods toward the outer circumference of the photonic crystal structure from the defect furthest from the first defect. (10) The display device according to any one of (1) to (9), wherein the plurality of defects are not provided in the second region. (11) The display device according to any one of (1) to (10), wherein the light-emitting element further comprises an on-chip lens provided on the side opposite to the light-emitting layer with respect to the first electrode, and the principal ray of the on-chip lens passes through the opening. (12) The display device according to any one of (1) to (11), wherein adjacent light-emitting elements are separated by a boundary. (13) The display device according to any one of (1) to (12), wherein the plurality of columnar bodies have a refractive index different from the refractive index of the surrounding layer of the plurality of columnar bodies. (14) The display device according to any one of (1) to (12), wherein the plurality of columnar bodies consist of cavities. (15) The display device according to any one of (1) to (14), wherein the diameter of the plurality of columnar bodies is smaller than the predetermined period length. (16) The display device according to any one of (1) to (15), wherein the plurality of columnar bodies penetrate the photonic crystal structure along the film thickness of the photonic crystal structure. (17) The display device according to any one of (1) to (16) above, wherein each of the plurality of columnar bodies is arranged at a position that is point-symmetric with respect to the center of the photonic crystal structure.(18) The display device according to any one of (1) to (17) above, wherein the light-emitting layer is made of an inorganic light-emitting material, an organic light-emitting material, a perovskite material, a colloidal quantum dot material, or a mixture thereof.

[0181] 10 Display device 11 Horizontal drive circuit 12 Vertical drive circuit 20 Pixel array section 40 Display panel 100 Light-emitting element 110 Substrate 120 Photonic crystal structure 122, 122 ａ１ , 122 ａ２ , 122 ｂ１ , 122 ｂ２ , 122 ｃ１ , 122 ｃ２ Columnar body 124 Photonic crystal layer 126, 126 ａ , 126 ｂ , 126 ｃ , 126 ｄ , 126 ｅ , 126 ｆ , 126 ｇ Defect 130 Lower electrode 132 Light-emitting layer 134 Upper electrode 140 Insulating layer 142 Aperture 150 Protective film 160 On-chip lens 170 Boundary 180 ａ , 180 ｂ Line segment 190, principal rays 400, 400B, 400G, 400R, subpixels

Claims

1. A display device having a plurality of light-emitting elements arranged on a substrate, wherein each light-emitting element comprises: an emitting layer; a first electrode and a second electrode sandwiching the emitting layer from above and below; a photonic crystal structure provided so as to face the emitting layer with the second electrode in between; and an insulating layer provided between the first electrode and the emitting layer, having an opening on the center of the photonic crystal structure, wherein the photonic crystal structure comprises: a plurality of columnar bodies arranged periodically with a predetermined period length in a first region overlapping the opening and a second region not overlapping the opening; and a plurality of defects provided within the first region so as to be separated from each other for three or more periods, which disrupt the period of the arrangement of the plurality of columnar bodies, wherein the first region of the photonic crystal structure is divided into a plurality of unit units, the plurality of unit units are arranged at positions that are n (an integer of 2 or more) rotationally symmetric with respect to the center of the photonic crystal structure as the rotational center, and each unit unit has at least three of the defects.

2. Each unit has a first defect located at the center of the photonic crystal structure, a second defect, and a third defect, and the plurality of columnar bodies include a plurality of first columnar bodies adjacent to and surrounding the first defect, a plurality of second columnar bodies adjacent to and surrounding the second defect, a plurality of third columnar bodies adjacent to and surrounding the third defect, and a plurality of fourth columnar bodies other than the first, second, and third columnar bodies, wherein the diameters of the first columnar bodies, the diameters of the second columnar bodies, and the diameters of the third columnar bodies are different from each other, and the diameters of the second and third columnar bodies are different from the average value of the diameters of the fourth columnar body, the display device according to claim 1.

3. The display device according to claim 2, wherein the center of the first columnar body is offset from a position a predetermined period length away from the center of the first defect, the center of the second columnar body is offset from a position a predetermined period length away from the center of the second defect, and the center of the third columnar body is offset from a position a predetermined period length away from the center of the third defect.

4. The plurality of columnar bodies further include: a plurality of fifth columnar bodies surrounding the first defect via the first columnar bodies; a plurality of sixth columnar bodies surrounding the second defect via the second columnar bodies; and a plurality of seventh columnar bodies surrounding the third defect via the third columnar bodies, wherein the centers of the fifth columnar bodies are offset from a position at a distance of twice the predetermined period length from the center of the first defect; the centers of the sixth columnar bodies are offset from a position at a distance of twice the predetermined period length from the center of the second defect; and the centers of the seventh columnar bodies are offset from a position at a distance of twice the predetermined period length from the center of the third defect, the display device according to claim 3.

5. Each unit has a first defect located at the center of the photonic crystal structure, a second defect, and a third defect, and the plurality of columnar bodies include a plurality of first columnar bodies adjacent to and surrounding the first defect, a plurality of second columnar bodies adjacent to and surrounding the second defect, and a plurality of third columnar bodies adjacent to and surrounding the third defect, the center of the first columnar body is offset from a position a predetermined period length away from the center of the first defect, the center of the second columnar body is offset from a position a predetermined period length away from the center of the second defect, and the center of the third columnar body is offset from a position a predetermined period length away from the center of the third defect, the display device according to claim 1.

6. The plurality of columnar bodies further include: a plurality of fifth columnar bodies surrounding the first defect via the first columnar bodies; a plurality of sixth columnar bodies surrounding the second defect via the second columnar bodies; a plurality of seventh columnar bodies surrounding the third defect via the third columnar bodies; and a plurality of eighth columnar bodies other than the first, second, third, fifth, sixth, and seventh columnar bodies, wherein the first, second, third, fifth, sixth, and seventh columnar bodies have different diameters from each other, and the diameters of the second, third, fifth, sixth, and seventh columnar bodies are different from the average value of the diameters of the eighth columnar body, as described in claim 5.

7. The display device according to claim 6, wherein the center of the fifth columnar body is offset from a position at a distance of twice the predetermined period length from the center of the first defect, the center of the sixth columnar body is offset from a position at a distance of twice the predetermined period length from the center of the second defect, and the center of the seventh columnar body is offset from a position at a distance of twice the predetermined period length from the center of the third defect.

8. The display device according to claim 1, wherein the plurality of unit units are regularly arranged so as to surround the center of the photonic crystal structure.

9. The display device according to claim 2, wherein the plurality of columnar bodies are arranged in four or more periods toward the outer periphery of the photonic crystal structure, starting from the defect furthest from the first defect.

10. The display device according to claim 1, wherein the plurality of defects are not provided in the second region.

11. The display device according to claim 1, wherein the light-emitting element further comprises an on-chip lens provided on the side opposite to the light-emitting layer with respect to the first electrode, and the principal ray of the on-chip lens passes through the opening.

12. The display device according to claim 1, wherein adjacent light-emitting elements are separated by a boundary.

13. The display device according to claim 1, wherein the plurality of columnar bodies have a refractive index different from that of the surrounding layer.

14. The display device according to claim 1, wherein the plurality of columnar bodies are hollow.

15. The display device according to claim 1, wherein the diameters of the plurality of columnar bodies are smaller than the predetermined period length.

16. The display device according to claim 1, wherein the plurality of columnar bodies penetrate the photonic crystal structure along the film thickness of the photonic crystal structure.

17. The display device according to claim 1, wherein each of the plurality of columnar bodies is arranged at a position that is point-symmetric with respect to the center of the photonic crystal structure.

18. The display device according to claim 1, wherein the light-emitting layer is made of an inorganic light-emitting material, an organic light-emitting material, a perovskite material, a colloidal quantum dot material, or a mixture thereof.

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