Display device

Abstract

Provided is a display device having a plurality of light-emitting elements arranged on a substrate, wherein: each of the light-emitting elements is provided with a light-emitting layer, a first photonic crystal structure that includes a periodic structure and one or more defects disturbing the periodic structure and that acts on light from the light-emitting layer, and an optical path control layer that acts to direct the path of light to the upper side of the light-emitting elements; and when the light-emitting elements are viewed from above, the optical path control layer is provided so as to overlap at least a part of a resonator including the defects of the first photonic crystal structure and a region around the defects.

Description

Display device

[0001] The present disclosure relates to a display device.

[0002] In recent years, development of display devices using self-emitting elements such as electroluminescence (EL) elements as light-emitting elements has advanced. In such a display device, for example, a plurality of light-emitting elements having a stacked structure formed by a lower electrode provided on a substrate, a light-emitting layer provided on the lower electrode, and an upper electrode provided on the light-emitting layer are arranged on the substrate. Then, 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 Application Laid-Open No. 7-15035

[0004] In the prior art, in order to guide the light radiated from the light-emitting layer toward the substrate upward above the light-emitting element, it is common to provide a reflection structure on the substrate. By doing so, since the light is reflected upward, the luminance of the display surface of the display device increases. However, by providing the reflection structure, external light incident on the display surface from the outside is reflected by the reflection structure and guided above the light-emitting element, so that the visibility of the display surface may decrease. Therefore, in order to suppress such reflection of external light, it has been proposed to provide a circular polarizing plate. However, if a circular polarizing plate is provided, the luminance rather decreases.

[0005] Therefore, the present disclosure proposes a display device that can efficiently increase the luminance while avoiding a decrease in visibility due to external light reflection.

[0006] According to the present disclosure, there is provided a display device having a plurality of light-emitting elements arranged on a substrate, wherein each of the light-emitting elements includes a light-emitting layer, a periodic structure, and one or more defects that disrupt the periodic structure, and a first photonic crystal structure that acts on the light from the light-emitting layer, and a light path control layer that acts to direct the light path upward above the light-emitting element, and when the light-emitting element is viewed from above, the light path control layer is provided so as to overlap at least a part of a resonator including the defect of the first photonic crystal structure and a region around the defect.

[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 (part 1) showing an example of the cross-sectional configuration of a photonic crystal structure according to the first embodiment of this disclosure. This is a schematic diagram (part 2) showing an example of the cross-sectional configuration of a photonic crystal structure according to the first 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 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 showing an example of the cross-sectional configuration of a light-emitting element according to the fourth embodiment of this disclosure. This is a schematic diagram (part 1) showing an example of a retroreflective layer according to the fourth embodiment of this disclosure. This is a schematic diagram (part 2) showing an example of a retroreflective layer according to the fourth embodiment of this disclosure. This is a schematic diagram (part 3) showing an example of a retroreflective layer according to the fourth embodiment of this disclosure. This is a schematic diagram (part 4) showing an example of a retroreflective layer according to the fourth 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 fifth 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 sixth 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 seventh 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 eighth 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 ninth embodiment of this disclosure. This is a schematic diagram (1) showing an example of the cross-sectional configuration of a photonic crystal structure according to the tenth embodiment of this disclosure. This is a schematic diagram (2) showing an example of the cross-sectional configuration of a photonic crystal structure according to the tenth embodiment of this disclosure. This is a schematic diagram (3) showing an example of the cross-sectional configuration of a photonic crystal structure according to the tenth embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a display panel according to the eleventh embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a photonic crystal structure in a display panel according to the eleventh embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a display panel according to the twelfth embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a photonic crystal structure in a display panel according to the twelfth embodiment of this disclosure.This is a schematic diagram (1) showing the manufacturing process of a light-emitting element according to the first embodiment of this disclosure. This is a schematic diagram (2) showing the manufacturing process of a light-emitting element according to the first embodiment of this disclosure. This is a schematic diagram (3) showing the manufacturing process of a light-emitting element according to the first embodiment of this disclosure. This is a conceptual diagram (1) for explaining 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 (2) for explaining 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 (3) for explaining 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 (4) for explaining 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. 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 selection part. This is a conceptual diagram (No. 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 selection 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 a resonator structure. This is a schematic cross-sectional view illustrating the second example of a resonator structure. This is a schematic cross-sectional view illustrating the third example of a resonator structure. This is a schematic cross-sectional view illustrating the fourth example of a resonator structure. This is a schematic cross-sectional view illustrating the fifth example of a resonator structure. This is a schematic cross-sectional view illustrating the sixth example of a resonator structure. This is a schematic cross-sectional view illustrating the 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 (No. 1) showing the internal configuration of an automobile. This is a diagram (No. 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 the present disclosure 1.1 Display device 1.2 Pixel 2. Background 3. First embodiment 4. Second embodiment 5. Third embodiment 6. Fourth embodiment 7. Fifth embodiment 8. Sixth embodiment 9. Seventh embodiment 10. Eighth embodiment 11. Ninth embodiment 12. Tenth embodiment 13. Eleventh embodiment 14. Twelfth embodiment 15. Manufacturing method 16. Summary 17. Modifications 17.1 Modification 1 17.2 Modification 2 18. Application examples 19. 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. Ｃａｔ (For example, ground potential) is supplied.

[0024] Here, let M be the number of scan lines SCL and power lines PS1. Subpixel 400 of the mth row (where m = 1, 2..., P) is the mth scan line SCL ｍ , the mth power supply line PS1 ｍ It is connected to and constitutes one row of display elements. Note that in Figure 2, the scan line SCL ｍand the power supply line PS1 ｍ Only is 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, 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 light emission / non-light emission timing is controlled in the row units 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 this. The light emitting element 100 is composed of an inorganic electroluminescence light emitting element or an organic electroluminescence light emitting element. The drive circuit is composed of a writing transistor TR Ｗ , and a drive transistor TR Ｄ , and a capacitance part C １ . When current flows through the drive transistor TR Ｄ to 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 FIG. 2, in the sub-pixel 400, one source / drain region of the drive transistor TR Ｄ is connected to one end of the capacitance part C １ and the power supply line PS1 ｍThe 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 it is in a conductive state, capacitance part C 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 １ The 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, the background to the inventors' creation of the embodiments of this disclosure will be explained.

[0033] As previously described, the light-emitting element 100 mounted on the display device 10 has a laminated structure consisting of a lower electrode provided on a substrate, a light-emitting layer laminated on the lower electrode, and an upper electrode laminated on the light-emitting layer. In conventional display devices 10, a reflective structure is generally provided on the substrate to guide the light emitted from the light-emitting layer toward the substrate upwards to the light-emitting element 100. In this way, the light is reflected upwards to the front of the display panel 40 of the display device 10, thereby increasing the brightness of the display panel 40.

[0034] However, by providing the above-mentioned reflective structure, ambient light incident on the display panel 40 from the outside is reflected by the reflective structure and guided upwards to the light-emitting element 100, which may reduce the visibility of the display panel 40 of the display device 10. Therefore, it has been proposed to provide a circular deflection plate on the surface of the display panel 40 to suppress such reflection of ambient light. However, providing a circular deflection plate would actually reduce the brightness of the display panel 40. Furthermore, if the current density is increased to emit stronger light from the light-emitting element 100 in order to compensate for this decrease in brightness, it would lead to an increase in the power consumption of the display device 10 and a decrease in the product lifespan.

[0035] Therefore, the inventors devised a method for providing 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 equal to the wavelength of light. Due to the bandgap effect of this periodic structure, light of a predetermined wavelength can be confined within it. Furthermore, if a disordered periodic structure (a minute defect) is introduced into the photonic crystal structure, light with a wavelength corresponding to the periodic structure of the photonic crystal structure will be confined and resonated in the defect and the region surrounding the defect. In other words, the defect and the region surrounding the defect can function as an optical resonator. Therefore, by providing a photonic crystal structure with introduced defects in the light-emitting element 100, the brightness can be further increased by confining and resonating light. Moreover, since the brightness is increased by optical resonance by providing a photonic crystal structure with introduced defects, the current density does not need to be increased, thus preventing an increase in the power consumption of the display device 10 and a decrease in product lifespan.

[0036] Furthermore, by more deeply examining the relative positions of the defective photonic crystal structure and the reflective structure, the inventors have come up with an embodiment of the present disclosure that can avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate.

[0037] In other words, according to the embodiments of this disclosure, brightness can be efficiently increased while avoiding a decrease in visibility due to external light reflection. As a result, according to the embodiments of this disclosure, an increase in power consumption of the display device 10 and a decrease in product lifespan can be avoided. The details of the embodiments of this disclosure created by the inventors will be described in order below.

[0038] <<3. First Embodiment>> First, the detailed configuration of the light-emitting element 100 according to the first embodiment of the present 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 corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. Figures 3B and 3C are schematic diagrams showing an example of the cross-sectional configuration of the photonic crystal structure 140 according to this embodiment, and correspond to the cross-section when the photonic crystal structure 140 is cut parallel to the plane of the substrate 110. Note that the right side of Figure 3B shows an enlarged view of the main part of the photonic crystal structure 140.

[0039] 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).

[0040] As shown in Figure 3A, the light-emitting element 100 according to this embodiment has a laminated structure in which a reflective layer (an example of an optical path control layer) 120, a low-reflectance layer 122, a low-refractive-index layer 130, a photonic crystal structure (a first photonic crystal structure) 140, a lower electrode 150, an emitting layer 152, and an upper electrode 154 are sequentially stacked on a substrate 110. The details of each element of the light-emitting element 100 according to this embodiment will be described below.

[0041] (Substrate 110) The substrate 110 can be formed from a semiconductor material such as silicon, or a transparent material such as silicon oxide (SiOx).

[0042] (Reflective layer 120) The reflective layer 120 is an example of a light path control layer that acts to direct the path of light upwards towards the light-emitting element 100. The reflective layer 120 is provided on the substrate 110. The reflective layer 120 can be formed from a material with high light reflectivity, for example, aluminum (Al), silver (Ag), gold (Au), copper (Cu), alloys thereof, or a stack of these. Alternatively, the reflective layer 120 can be formed from a stack of dielectric layers, or from a stack of the above-mentioned metal layer and dielectric layer.

[0043] In this embodiment, the reflective layer 120 is smaller than the size of the light-emitting element 100 (photonic crystal structure 140). More specifically, as shown in Figure 3C, when the light-emitting element 100 is viewed from above, it does not overlap with the outer periphery of the photonic crystal structure 140, which will be described later. Furthermore, in this embodiment, as shown in Figure 3C, the reflective layer 120 is provided so as to overlap with at least a portion of the resonator region 148 (see Figure 3B), which includes the defect 146 of the photonic crystal structure 140 and the region surrounding the defect 146. In this embodiment, by providing the reflective layer 120 in this way, external light reflection can be suppressed while efficiently reflecting light from the resonator region 148 of the photonic crystal structure 140 upwards to the light-emitting element 100. Details of the positional relationship between the reflective layer 120 and the resonator region 148 of the photonic crystal structure 140 will be described later with reference to Figure 3C.

[0044] (Low-reflection layer 122) Furthermore, in this embodiment, as shown in Figure 3A, a low-reflection layer 122 is provided around the reflective layer 120 on the substrate 110. In this embodiment, although the details will be described later, in order to suppress the reflection of ambient light incident from outside the light-emitting element 100 and to avoid a decrease in the visibility of the display panel 40 of the display device 10, a low-reflection layer 122 that reflects less light than the reflective layer 120 is provided around the reflective layer 120.

[0045] The low-reflection layer 122 may be a light-absorbing layer such as a black matrix layer. The black matrix layer consists of, for example, a black resin film with an optical density of 1 or more mixed with a black coloring agent (specifically, for example, a black polyimide resin). Alternatively, the low-reflection layer 122 can be formed from, for example, an anti-reflective film. The anti-reflective film can suppress light reflection by utilizing light interference. The above anti-reflective film may be, for example, titanium oxide (TiO2). ｘ ), tantalum oxide (TaO ｘ ), niobium oxide (NbO ｘ A high refractive index film made of ) and silicon oxide (SiO ｘThe low-reflection layer 122 may be a laminated structure in which a low-refractive-index film made of silicon oxynitride (SiON) or the like is alternately stacked. Furthermore, the low-refractive-index layer 122 may be a single-layer or laminated film designed to weaken optical interference in a desired wavelength range, for example, as in a bandpass filter.

[0046] (Low refractive index layer 130) A low refractive index layer 130 is provided on the reflective layer 120 and the low-reflective layer 122 described above. The low refractive index layer 130 is made of a low refractive index material having a refractive index of 2 or less, and can confine light in the photonic crystal structure 140 described later. The low refractive index layer 130 is made of, for example, silicon oxide (SiO ｘ ), silicon oxynitride (SiO ｘ N ｙ ), silicon nitride (SiN ｘ It can be formed from inorganic insulating materials such as ), or organic resin materials such as acrylic resins or polyimide resins. The low refractive index layer 130 may also be a single layer or a laminate of the above-mentioned material.

[0047] (Photonic crystal structure 140) As explained earlier, the photonic crystal structure 140 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 from the light-emitting layer 152 can be confined (acted upon) inside. Furthermore, by introducing local periodic disorder (defect 146) into the photonic crystal structure 140, light in the band gap band determined by the periodic structure is confined in the defect and the surrounding region, so that the above region can function as an optical resonator.

[0048] In this embodiment, the photonic crystal structure 140 is a two-dimensional slab-type photonic crystal structure provided on a low refractive index layer 130. As shown in Figure 3A, the photonic crystal structure 140 has a structure in which, for example, a plurality of columnar bodies 144 having nanoscale diameters are periodically arranged within the photonic crystal layer 142. Furthermore, each columnar body 144 penetrates the photonic crystal layer 142 along the film thickness direction of the photonic crystal layer 142. The columnar bodies 144 can be made of a material with a different refractive index from the material of the photonic crystal layer 142, or they can be voids. Specifically, for example, if the photonic crystal layer 142 is formed from silicon nitride (SiNx) (refractive index 1.83), the columnar bodies 144 can be formed from hydrogen silsesquioxane (HSQ) (refractive index 1.4). In this embodiment, it is preferable that the columnar body 144 is formed from a material with a different refractive index from the surrounding material, which makes deformation of the photonic crystal structure 140 less likely compared to the case where it is made of a cavity.

[0049] Furthermore, in this embodiment, as shown in Figure 3B, the multiple cylindrical columnar bodies 144 are arranged at positions that are point-symmetric with respect to the center of the hexagonal photonic crystal structure 140.

[0050] Furthermore, in this embodiment, as shown in Figure 3A, for example, a defect 146 is introduced in the central region of the photonic crystal structure 140 where the periodic arrangement of columnar bodies 144 is disrupted; in this example, a defect 146 where no columnar bodies 144 exist. In this embodiment, light having a wavelength corresponding to the periodic structure of the photonic crystal structure 140 is confined and resonated in a resonator consisting of the defect 146 and the region surrounding the defect 146. In detail, in the planar direction of the photonic crystal structure 140, due to the bandgap effect caused by the periodic structure, light having a predetermined wavelength is confined to the defect 146 and the region surrounding the defect 146. Therefore, in this embodiment, the brightness can be efficiently increased by confining and resonating the light from the light-emitting layer 152 in the defect 146 and the region surrounding the defect 146. In other words, in this embodiment, the defect 146 and the region surrounding the defect 146 function as an optical resonator. In addition, in this embodiment, since light is confined to the resonator in the planar direction of the photonic crystal structure 140, much of the light from the resonator is extracted in the direction of the film thickness of the photonic crystal structure 140. Therefore, in this embodiment, the resonator can limit the position from which a large amount of light is emitted and control the direction (radiation angle) of light emission.

[0051] In this embodiment, as shown in Figure 3B, the defect 146 and the surrounding area of ​​the defect 146 function as a resonator and are therefore referred to as the resonator region 148. More specifically, as shown in Figure 3B, the resonator region 148 is the region adjacent to the defect 146 and connected by the centers of the multiple columnar bodies 144 surrounding the defect 146 (the hexagonal region enclosed by the dashed line in the enlarged view). That is, as explained earlier, the resonator region 148 can efficiently increase brightness by confining and resonating light, and can also radiate light in the film thickness direction of the photonic crystal structure 140.

[0052] Furthermore, in this embodiment, the volume of the resonator region 148 (or the resonator region 148) is preferably very small, which makes the mode volume (V) of the resonator very small. According to this embodiment, by using a resonator with a very small mode volume (V), the brightness can be increased more efficiently by the Purcell effect. Specifically, since the photon density in an 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 a resonator, the speed and intensity (brightness) of light emission can be increased by the Purcell effect.

[0053] In this embodiment, when the light-emitting element 100 is viewed from above, as shown in Figure 3C, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148 of the photonic crystal structure 140. Furthermore, in this embodiment, in order to reflect light from the resonator region 148 more efficiently, it is preferable that the reflective layer 120 is provided so as to overlap the entire resonator region 148, as shown in the upper part of Figure 3C. In this embodiment, by providing the reflective layer 120 in this manner, light from the resonator region 148 of the photonic crystal structure 140 can be efficiently reflected upwards to the light-emitting element 100.

[0054] Furthermore, in this embodiment, as previously described, when the light-emitting element 100 is viewed from above, as shown in Figure 3C, the reflective layer 120 is smaller than the size of the light-emitting element 100 and does not overlap with the outer periphery of the photonic crystal structure 140. Here, the outer periphery of the photonic crystal structure 140 refers to the area from the region where the multiple columnar bodies 144 located at the outermost periphery of the photonic crystal structure 140 are arranged to the outer periphery (contour) of the photonic crystal structure 140.

[0055] If ambient light incident from outside the light-emitting element 100 is reflected by the reflective layer 120, the visibility of the display panel 40 of the display device 10 will decrease. Therefore, in this embodiment, in order to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light, the reflective layer 120 is made smaller than the size of the light-emitting element 100. Furthermore, in this embodiment, in order to suppress the reflection of ambient light, it is preferable that the reflective layer 120 is provided so as not to overlap with the outer periphery of the photonic crystal structure 140. That is, in this embodiment, in order to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light, it is more preferable that the reflective layer 120 overlaps with the entire resonator region 148 and is made as small as possible, as shown in the upper left of Figure 3C. In addition, in this embodiment, in order to further suppress the reflection of ambient light, a low-reflection layer 122 is provided around the reflective layer 120, which reflects less light than the reflective layer 120.

[0056] (Lower electrode 150) In this embodiment, as shown in Figure 3A, the lower electrode 150 is provided together with the upper electrode 154, which will be described later, so as to sandwich the light-emitting layer 152 from above and below. In detail, the lower electrode 150 can be formed from 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 150 can be formed from a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO).

[0057] (Light-emitting layer 152) The light-emitting layer 152 can be formed from an organic material or the like, and for example, has a structure in which 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. The stacking order of the light-emitting layer 152 is not limited to the order described above, and may be stacked in an inverted order.

[0058] The hole-injection layer can be composed of, for example, hexaazatriphenylene (HAT).

[0059] 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].

[0060] 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 150 via the hole injection layer and hole transport layer recombine with some of the electrons injected from the upper electrode 154 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).

[0061] 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 150 via the hole injection layer, hole transport layer, and light emission separation layer recombine with some of the electrons injected from the upper electrode 154 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).

[0062] 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 150 via the hole injection layer, hole transport layer, and light emission separation layer recombine with some of the electrons injected from the upper electrode 154 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.

[0063] 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.

[0064] Furthermore, an electron injection layer may be provided between the electron transport layer and the upper electrode 154. 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.

[0065] Furthermore, a buffer layer may be provided between the electron transport layer and the upper electrode 154. The buffer layer is intended to mitigate process damage to the light-emitting layer 152 during the deposition of the upper electrode 154. 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.

[0066] Furthermore, in this embodiment, the light-emitting layer 152 can be formed from an inorganic material or the like, and may have a laminated light-emitting structure in which the active layer is sandwiched between two compound semiconductor layers. The laminated light-emitting structure can be composed of, for example, a GaN-based compound semiconductor (including AlGaN mixed crystal, AlInGaN mixed crystal, or GaInN mixed crystal), an AlGaInAs-based compound semiconductor, an AlGaInP-based compound semiconductor, a ZnSe-based compound semiconductor (for example, including ZnS, ZnSSe, and ZnMgSSe), or a ZnO-based compound semiconductor. More specifically, AlInGaN-based compound semiconductors include 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, etc.

[0067] The active layer preferably has a quantum well structure. Specifically, the active layer may have a single quantum well structure (SQW structure) or a multiple quantum well structure (MQW structure). More specifically, the single quantum well structure has a structure in which a semiconductor layer with a thickness of several tens of nanometers or less is sandwiched on both sides by layers with a larger band gap than the semiconductor layer. Since the potential of the layer with the smaller band gap is lower than that of the layer with the larger band gap, a potential well (quantum well) is created. Furthermore, stacking several to tens of such quantum well structures results in a multiple quantum well structure.

[0068] The active layer having a quantum well structure has a structure in which at least one well layer and a barrier layer are stacked, and the combination of (compound semiconductor constituting the well layer, compound semiconductor constituting the barrier layer) is, for example, (InyGa (１－ｙ） N, GaN), (InyGa （１－ｙ） N, InzGa （１－ｚ） N) [where y > z], (InyGa （１－ｙ） Examples include N, AlGaN, etc. Furthermore, one compound semiconductor layer may be composed of a compound semiconductor of a first conductivity type (e.g., n-type), and the other compound semiconductor layer may be composed of a compound semiconductor of a second conductivity type (e.g., p-type) different from the first conductivity type. Moreover, these compound semiconductor layers may be single-structure layers, multilayer layers, or superlattice layers. In addition, the compound semiconductor layers may be composition-graded layers or concentration-graded layers.

[0069] Furthermore, the quantum well structure may be, for example, a one-dimensional quantum well structure (quantum wire), a zero-dimensional quantum well structure (quantum dot), or the like.

[0070] (Upper electrode 154) In this embodiment, the upper electrode 154 can be formed from, for example, a transparent conductive material with good light transmittance to visible light. For example, the upper electrode 154 can be formed from a transparent conductive oxide such as ITO, IZO, or ZnO.

[0071] As described above, in this embodiment, the reflective layer 120 is provided so as to overlap with at least a portion of the resonator region 148 of the photonic crystal structure 140. Furthermore, in this embodiment, a low-reflection layer 122 is provided around the reflective layer 120, which reflects less light than the reflective layer 120. In this way, in this embodiment, it is possible to reflect light from the resonator region 148 more efficiently while suppressing the reflection of ambient light. As a result, in this embodiment, it is possible to avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate. Furthermore, in this embodiment, since the brightness is efficiently increased by the optical resonance of the photonic crystal structure 140 in which defects have been introduced, the current density does not need to be increased, and therefore, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan.

[0072] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figures 3A, 3B, and 3C, but can be transformed into various forms.

[0073] <<4. Second Embodiment>> Next, with reference to Figure 4, the detailed configuration of the light-emitting element 100 according to the second embodiment of the present disclosure will be described. Figure 4 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. In the following description, points that are common with the first embodiment described above will be omitted from the explanation.

[0074] In this embodiment, as shown in Figure 4, a light-transmitting layer 124 that selectively transmits light of a predetermined wavelength is provided around the reflective layer 120 instead of a low-reflection layer 122. Furthermore, in this embodiment, the light-transmitting layer 124 consists of a color filter that transmits light having the same wavelength as the light emitted from the light-emitting layer 152 of the light-emitting element 100, for example, a color filter of the same color as the light emitted from the light-emitting element 100. Alternatively, in this embodiment, a color conversion layer that converts incident light into light of a predetermined wavelength may be provided around the reflective layer 120. Furthermore, in this embodiment, the color conversion layer is capable of converting light into light having the same wavelength as the light emitted from the light-emitting layer 152 of the light-emitting element 100. In this embodiment, the light-transmitting layer 124 and the color conversion layer can be formed from, for example, a color filter, quantum dots, or a layer in which metal nanoparticles that generate localized surface plasmon resonance are dispersed.

[0075] The operation of the light-transmitting layer 124 according to this embodiment will be described below. In the example described below, the light-transmitting layer 124 is assumed to be a green color filter, the same as the color of light emitted by the light-emitting element 100. In such an example, when ambient light is incident on the light-emitting element 100, light with wavelengths corresponding to colors other than green is absorbed by the light-transmitting layer 124. Light corresponding to the green wavelength of ambient light passes through the light-transmitting layer 124 and is reflected upward by the substrate 110 towards the light-emitting element 100. At first glance, it might seem that the visibility of the display panel 40 of the display device 10 would decrease because ambient light is reflected. However, in this embodiment, since only green ambient light is reflected, the intensity of the green light that the light-emitting element 100 should emit is increased by the reflected ambient light, and the visibility of the light emitted from the light-emitting element 100 does not decrease. In other words, according to this embodiment, it is possible to efficiently increase brightness by reflecting ambient light while avoiding a decrease in visibility due to ambient light reflection.

[0076] In addition, in this embodiment as well, similar to the first embodiment, the reflective layer 120 is provided so as to overlap with at least a portion of the resonator region 148 of the photonic crystal structure 140, as shown in Figure 4. Therefore, in this embodiment, the brightness can be increased efficiently because the light from the resonator region 148 is reflected more efficiently.

[0077] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 4, but can be transformed into various forms.

[0078] <<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 this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. In the following description, points that are common with the first embodiment described above will be omitted from the explanation.

[0079] In this embodiment, unlike the first embodiment, as shown in Figure 5, no low-reflection layer 122 or the like is provided around the reflective layer 120. In addition, in this embodiment as well, similar to the first embodiment, the reflective layer 120 is provided so as to overlap with at least a part of the resonator region 148 of the photonic crystal structure 140.

[0080] Therefore, in this embodiment, even without the low-reflection layer 122, the surface of the substrate 110 surrounding the reflective layer 120 has a lower light reflectivity than the reflective layer 120, so although the effect is weaker compared to the first embodiment, the reflection of ambient light can be suppressed. As a result, in this embodiment as well, a decrease in visibility due to ambient light reflection can be avoided without using a circular deflection plate. Furthermore, in this embodiment, since the brightness is efficiently increased by the optical resonance of the photonic crystal structure 140 in which defects have been introduced, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan. Moreover, according to this embodiment, since the low-reflection layer 122 is not provided, the configuration of the display device 10 can be simplified compared to the first embodiment, and the increase in manufacturing time and manufacturing cost of the display device 10 can be suppressed.

[0081] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 5, but can be transformed into various forms.

[0082] <<6. Fourth Embodiment>> Next, the detailed configuration of the light-emitting element 100 according to the fourth embodiment of the present disclosure will be described with reference to Figures 6A to 6E. Figure 6A is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to the present embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. Figures 6B and 6C are schematic diagrams showing an example of the retroreflective layer 126 according to the present embodiment, and the right side of the figure shows an enlarged view of the beads 162 and 162a included in the retroreflective layer 126. Figure 6D is a schematic diagram showing an example of the retroreflective layer 126 according to the present embodiment, and the lower side of the figure shows an enlarged view of the corner cube structure 166 included in the retroreflective layer 126. Figure 6E is a schematic diagram showing an example of the retroreflective layer 126 according to the embodiment, and the left side of the figure shows a cross-section of the retroreflective layer 126, and the right side of the figure shows a plan view of the retroreflective layer 126. In the following explanation, we will omit explanations of points that are common to the first embodiment described above.

[0083] In the embodiments of the present disclosure described above, light from the resonator region 148 of the photonic crystal structure 140 is emitted with a certain degree of spread from the resonator region 148. Therefore, a portion of the light from the resonator region 148 is incident obliquely on the reflective layer 120 and further reflected obliquely from the reflective layer 120. A portion of the light reflected in this way may be confined to the portion of the photonic crystal structure 140 other than the resonator region 148 and become inactive. In such cases, the light emitted from the light-emitting layer 152 cannot be effectively utilized, leading to a decrease in the luminous efficiency of the light-emitting element 100. Furthermore, a portion of the reflected light is further reflected outside the resonator region 148, becoming stray light, and light is emitted from unintended locations, leading to a decrease in the quality of the image displayed on the display device 10 (reduced visibility).

[0084] Therefore, in this embodiment, as shown in Figure 6A, a retroreflective layer 126 (an example of an optical path control layer) is used instead of the reflective layer 120. The surface (reflective surface) of the retroreflective layer 126 can reflect light toward the light source corresponding to the incident light, regardless of the direction from which the light is incident. Accordingly, in this embodiment, as shown in Figure 6A, light from the resonator region 148 can return to the resonator region 148 once it is reflected by the retroreflective layer 126. In detail, light from the resonator region 148 will return to the resonator region 148 whether it is incident on the surface of the retroreflective layer 126 from a direction perpendicular to the surface of the retroreflective layer 126 or from an oblique angle to the surface of the retroreflective layer 126. The light that returns to the resonator region 148 is then confined to the resonator region 148 and resonates again.

[0085] Therefore, in this embodiment, by using the retroreflective layer 126, the light reflected by the retroreflective layer 126 returns to the resonator region 148, thereby suppressing the confinement and deactivation of light in the photonic crystal structure 140 other than the resonator region 148. As a result, according to this embodiment, a decrease in the luminous efficiency of the light-emitting element 100 can be avoided. In addition, in this embodiment, by using the retroreflective layer 126, the light reflected by the retroreflective layer 126 returns to the resonator region 148, thereby suppressing the stray light that is reflected outside the resonator region 148. As a result, according to this embodiment, a decrease in the image quality (reduced visibility) of the display device 10 can be avoided.

[0086] For example, the retroreflective layer 126 can be formed from a substrate 160 containing a plurality of transparent beads 162, as shown on the left side of Figure 6B. As shown on the right side of Figure 6B, due to the refractive index difference between the beads 162 and the substrate 160, light is reflected at the spherical interface between the beads 162 and the substrate 160, and the reflected light propagates towards the light source corresponding to that light.

[0087] Furthermore, as shown on the left side of Figure 6C, for example, a portion of the surface of the transparent bead 162a embedded in the substrate 160 may be covered with the coating film 164. As shown on the right side of Figure 6C, due to the refractive index difference between the bead 162a and the coating film 164, light is reflected at the spherical interface between the bead 162a and the coating film 164, and the reflected light propagates towards the light source corresponding to that light.

[0088] Furthermore, for example, the retroreflective layer 126 may have a surface (reflective surface) on which multiple corner cube structures 166 are formed, as shown in the upper part of Figure 6D. As shown in the lower part of Figure 6D, the corner cube structure 166 has multiple surfaces that intersect perpendicularly to each other. As shown in the lower part of Figure 6D, when light is incident on one surface of the corner cube structure 166, the light is reflected, then incident on one or more other surfaces of the corner cube structure 166, is reflected again, and travels out of the corner cube structure 166. Therefore, the light reflected by the corner cube structure 166 travels towards the light source corresponding to that light.

[0089] Furthermore, for example, the retroreflective layer 126 may have a surface (reflective surface) on which multiple corner cube structures 170 are formed, as shown in Figure 6E. As shown in Figure 6E, the corner cube structure 170 has multiple faces that constitute a triangular pyramid. As shown in Figure 6E, when light is incident on one face of the corner cube structure 170, the light is reflected, then incident on another face of the corner cube structure 170, is reflected again, and travels out of the corner cube structure 170. Therefore, the light reflected by the corner cube structure 170 travels towards the light source corresponding to that light.

[0090] In this embodiment, it is preferable to determine the shape, size, etc. of the beads 162, 162a and the corner cube structures 166, 170 according to the angle of light emission from the resonator region 148.

[0091] In this embodiment as well, the retroreflective layer 126 is provided so as to overlap with at least a portion of the resonator region 148 of the photonic crystal structure 140. Furthermore, in this embodiment as well, a low-reflectivity layer 122 is provided around the retroreflective layer 126, which reflects less light than the reflective layer 120.

[0092] As described above, in this embodiment, by using the retroreflective layer 126, the light reflected by the retroreflective layer 126 returns to the resonator region 148, thereby suppressing the confinement and deactivation of light in the photonic crystal structure 140 other than the resonator region 148. As a result, according to this embodiment, a decrease in the luminous efficiency of the light-emitting element 100 can be avoided. In addition, in this embodiment, by using the retroreflective layer 126, the light reflected by the retroreflective layer 126 returns to the resonator region 148, thereby suppressing the stray light that is reflected outside the resonator region 148. As a result, according to this embodiment, a decrease in the image quality (reduced visibility) of the display device 10 can be avoided.

[0093] In addition, in this embodiment, the retroreflective layer 126 is provided so as to overlap at least a portion of the resonator region 148 of the photonic crystal structure 140. Furthermore, in this embodiment, a low-reflection layer 122 is provided around the retroreflective layer 126, which reflects less light than the retroreflective layer 126. In this way, in this embodiment, light from the resonator region 148 can be reflected more efficiently while suppressing the reflection of ambient light. As a result, in this embodiment, a decrease in visibility due to ambient light reflection can be avoided without using a circular deflection plate. Furthermore, in this embodiment, since the brightness is efficiently increased by the optical resonance of the photonic crystal structure 140 into which defects have been introduced, the current density does not need to be increased, and therefore, the power consumption of the display device 10 does not increase and the product lifespan does not decrease.

[0094] In this embodiment, the retroreflective layer 126 is not limited to the form shown in Figures 6B to 6E, but can be modified to various forms. Furthermore, the retroreflective layer 126 according to this embodiment may be applied to the second and third embodiments, for example, in addition to the first embodiment described above.

[0095] <<7. Fifth Embodiment>> Next, with reference to Figure 7, the detailed configuration of the light-emitting element 100 according to the fifth embodiment of the present disclosure will be described. Figure 7 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. In the following description, points that are common with the first embodiment described above will be omitted from the explanation.

[0096] In the embodiments of the present disclosure described above, a reflective layer 120 or the like was provided as an optical path control layer that acts to direct the path of light upwards to the light-emitting element 100. However, this embodiment is not limited to this form, and a photonic crystal structure (second photonic crystal structure) 140a that functions as an optical path control layer may also be provided.

[0097] In detail, in this embodiment, the photonic crystal structure 140a can be a two-dimensional slab-type photonic crystal structure provided on the substrate 110. For example, as shown in Figure 7, the photonic crystal structure 140a has a structure in which a plurality of columnar bodies 144 with nanoscale diameters are periodically arranged within the photonic crystal layer 142. In addition, in the photonic crystal structure 140a, each columnar body 144 penetrates the photonic crystal layer 142 along the film thickness direction of the photonic crystal layer 142 and can be made of a material with a different refractive index than the material of the photonic crystal layer 142, or it can be a cavity. Furthermore, in this embodiment, as shown in Figure 7, for example, a defect 146 is introduced in the central region of the photonic crystal structure 140a.

[0098] In addition, in this embodiment, it is preferable that the columnar bodies 144a of the photonic crystal structure 140a located away from the defects 146 are formed from the same material (low-reflection material) as the low-reflection layer 122 in the first embodiment. By doing so, the reflection of ambient light can be suppressed in this embodiment.

[0099] However, in this embodiment, as shown in Figure 7, the resonator region 148a including the defect 146 of the photonic crystal structure 140a is provided so as to overlap with at least a portion of the resonator region 148 including the defect 146 of the photonic crystal structure 140. In this embodiment, the resonator region 148a of the photonic crystal structure 140a is provided so as to overlap with the resonator region 148 of the photonic crystal structure 140. In this way, according to this embodiment, the resonator region 148a can capture, confine, and resonate light from the light-emitting layer 152 and the photonic crystal structure 140. Furthermore, in this embodiment, the resonator region 148 can capture, confine, and resonate light from the resonator region 148a. Therefore, the brightness can be further increased.

[0100] Furthermore, in this embodiment, since light is confined to the resonator region 148a in the planar direction of the photonic crystal structure 140a, much of the light from the resonator region 148a is extracted in the direction of the film thickness of the photonic crystal structure 140a. In other words, the resonator region 148a of the photonic crystal structure 140a can limit the position from which a large amount of light is emitted and control the direction of light emission (radiation angle). Therefore, since the resonator region 148a radiates light toward the photonic crystal structure 140, it can be said that it is an optical path control layer that has the function of controlling the direction of light emission. In this embodiment, it is preferable to control the direction of light emission (radiation angle) by suitably adjusting the shape and size of the resonator region 148a, thereby reflecting more light toward the resonator region 148 of the photonic crystal structure 140.

[0101] In this embodiment, the photonic crystal structure 140 and the photonic crystal structure 140a may be the same or different in terms of their film thickness, material, number, shape, and size of the columnar bodies 144. If the shape, etc., of the photonic crystal structure 140 and the photonic crystal structure 140a are the same, the design and manufacturing processes can be standardized, thereby suppressing an increase in design and manufacturing costs. On the other hand, if the shape, etc., of the photonic crystal structure 140 and the photonic crystal structure 140a are different, each photonic crystal structure 140 and 140a can be optimized to have the desired characteristics.

[0102] Furthermore, in this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 7, but can be transformed into various forms. Also, the columnar body 144a of the photonic crystal structure 140a according to this embodiment may be formed from the same material as the light-transmitting layer 124 according to the second embodiment.

[0103] <<8. Sixth Embodiment>> Next, with reference to Figure 8, the detailed configuration of the light-emitting element 100 according to the sixth embodiment of the present disclosure will be described. Figure 8 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. In the following description, the explanation of points that are common with the first embodiment described above will be omitted.

[0104] In the embodiments of the present disclosure described above, the columnar body 144 of the photonic crystal structure 140 penetrated the photonic crystal layer 142 along the film thickness direction of the photonic crystal layer 142. However, the embodiment is not limited to this configuration, and the columnar body 144 may also penetrate at least a portion of the low refractive index layer 130 in addition to the photonic crystal layer 142, along the film thickness direction of the low refractive index layer 130. In this embodiment, for example, as shown in Figure 8, the columnar body 144 penetrates the photonic crystal layer 142 and the low refractive index layer 130 along their respective film thickness directions.

[0105] In this embodiment, the columnar members 144 of the photonic crystal structure 140 are provided so as to penetrate the photonic crystal layer 142 and the low refractive index layer 130. In this way, according to this embodiment, light can be confined in the planar direction of the photonic crystal structure 140 across the photonic crystal layer 142 and the low refractive index layer 130. As a result, according to this embodiment, the spread of light (emission angle) can be suppressed to a small extent, thereby improving the precision of controlling the direction of light emission by the photonic crystal structure 140.

[0106] In addition, in this embodiment as well, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148 of the photonic crystal structure 140. Furthermore, in this embodiment, a low-reflection layer 122 is provided around the reflective layer 120, which reflects less light than the reflective layer 120. In this way, in this embodiment as well, it is possible to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light. As a result, in this embodiment, it is possible to avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate. Furthermore, in this embodiment, since the brightness is efficiently increased by the optical resonance of the photonic crystal structure 140 into which defects have been introduced, the current density does not need to be increased, and therefore, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan.

[0107] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 8, but can be transformed into various forms. Furthermore, the photonic crystal structure 140b according to this embodiment may be applied not only to the first embodiment described above, but also to, for example, the second to fourth embodiments.

[0108] <<9. Seventh Embodiment>> Next, with reference to Figure 9, the detailed configuration of the light-emitting element 100 according to the seventh embodiment of the present disclosure will be described. Figure 9 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. Furthermore, the right side of Figure 9 shows an enlarged view of the photonic crystal structure 140c. Note that in the following description, the explanation of points common to the first embodiment described above will be omitted.

[0109] In the embodiments of the present disclosure described above, the photonic crystal structure 140 was described as a two-dimensional slab-type photonic crystal structure. However, the embodiments are not limited to this form, and the photonic crystal structure 140 may be a three-dimensional photonic crystal structure 140c, as shown in Figure 9.

[0110] For example, the three-dimensional photonic crystal structure 140c according to this embodiment can be a woodpile-type photonic crystal structure. As shown on the right side of Figure 9, the woodpile-type photonic crystal structure 140c is formed by alternately stacking a photonic crystal layer 142 in which a plurality of columnar bodies 144 penetrating the photonic crystal layer 142 are arranged periodically, and a photonic crystal layer 142 that does not contain a plurality of columnar bodies 144. Even in such a woodpile-type photonic crystal structure 140c, defects 146, which are locations where the periodic arrangement of the columnar bodies 144 is disrupted, can be introduced.

[0111] Alternatively, in this embodiment, the woodpile-type photonic crystal structure 140c may be formed by alternately stacking layers consisting of multiple rods extending in the X-axis direction arranged parallel and periodically, and layers consisting of multiple other rods extending in the Y-axis direction arranged parallel and periodically. In such a woodpile-type photonic crystal structure, defects 146, which are locations where the periodic arrangement of the rods is disrupted, can be introduced.

[0112] In this embodiment, by using a three-dimensional photonic crystal structure 140c, light can be confined more strongly not only in the planar direction of the photonic crystal structure 140c but also in the film thickness direction of the photonic crystal structure 140c. Therefore, according to this embodiment, light can be confined in the resonator region 148 at an extremely high density for a long period of time, thereby increasing the brightness.

[0113] In addition, in this embodiment as well, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148 of the photonic crystal structure 140c. Furthermore, in this embodiment, a low-reflection layer 122 is provided around the reflective layer 120, which reflects less light than the reflective layer 120. In this way, in this embodiment as well, it is possible to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light. As a result, in this embodiment, it is possible to avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate. Furthermore, in this embodiment, since the brightness is efficiently increased by the optical resonance of the photonic crystal structure 140c in which defects have been introduced, the current density does not need to be increased, and therefore, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan.

[0114] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 9, but can be transformed into various forms. In this embodiment, for example, the photonic crystal structure can be various two-dimensional or three-dimensional photonic crystal structures into which the defects 146 are introduced. Furthermore, the photonic crystal structure 140c according to this embodiment may be applied not only to the first embodiment described above, but also to, for example, the second to sixth embodiments.

[0115] <<10. Eighth Embodiment>> Next, with reference to Figure 10, the detailed configuration of the light-emitting element 100 according to the eighth embodiment of the present disclosure will be described. Figure 10 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. In the following description, the explanation of points that are common with the first embodiment described above will be omitted.

[0116] In the embodiments of the present disclosure described above, the photonic crystal structure 140 was located below the stacking of the lower electrode 150, the light-emitting layer 152, and the upper electrode 154. However, the embodiment is not limited to this configuration, and the photonic crystal structure 140 may be located above the stacking of the lower electrode 150, the light-emitting layer 152, and the upper electrode 154, as shown in Figure 10. More specifically, in this embodiment, as shown in Figure 10, the stacking of the lower electrode 150, the light-emitting layer 152, and the upper electrode 154 is provided on the low refractive index layer 130, and the photonic crystal structure 140 is provided on this stacking.

[0117] Furthermore, in this embodiment as well, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148 of the photonic crystal structure 140. In addition, in this embodiment as well, a low-reflection layer 122 is provided around the reflective layer 120, which reflects less light than the reflective layer 120. In this way, in this embodiment as well, it is possible to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light. As a result, in this embodiment as well, it is possible to avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate. Furthermore, in this embodiment as well, since the brightness is efficiently increased by the optical resonance of the photonic crystal structure 140 into which defects have been introduced, the current density does not need to be increased, and therefore, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan.

[0118] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 10, but can be transformed into various forms. Furthermore, the light-emitting element 100 according to this embodiment may be applied not only to the first embodiment described above, but also, for example, to the second to fourth embodiments and the seventh embodiment.

[0119] <<11. Ninth Embodiment>> Next, with reference to Figure 11, the detailed configuration of the light-emitting element 100 according to the ninth embodiment of the present disclosure will be described. Figure 11 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to this embodiment, and corresponds to the cross-section when the light-emitting element 100 is cut along the stacking direction of the light-emitting element 100. In the following description, the explanation of points that are common with the first embodiment described above will be omitted.

[0120] In the embodiments of the present disclosure described above, the photonic crystal structure 140 was located below the stacking of the lower electrode 150, the light-emitting layer 152, and the upper electrode 154. However, the embodiment is not limited to this configuration, and the photonic crystal structure 140d may be located within the stacking of the lower electrode 150, the light-emitting layer 152, and the upper electrode 154, as shown in Figure 11. More specifically, in this embodiment, as shown in Figure 11, the columnar body 144 of the photonic crystal structure 140d penetrates the stacking of the lower electrode 150, the light-emitting layer 152, and the upper electrode 154 along the stacking direction. In this embodiment, in order to suppress the degradation of the light-emitting layer 152 due to the penetration of the columnar body 144, it is preferable that the light-emitting layer 152 be formed from an inorganic material. For example, the light-emitting layer 152 may be a stacked light-emitting structure made of a compound semiconductor.

[0121] Furthermore, in this embodiment as well, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148 of the photonic crystal structure 140d. In addition, in this embodiment as well, a low-reflection layer 122 is provided around the reflective layer 120, which reflects less light than the reflective layer 120. In this way, in this embodiment as well, it is possible to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light. As a result, in this embodiment as well, it is possible to avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate. Furthermore, in this embodiment as well, since the brightness is efficiently increased by the optical resonance of the defective photonic crystal structure 140d, the current density does not need to be increased, and therefore, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan.

[0122] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 11, but can be transformed into various forms. Furthermore, the photonic crystal structure 140b according to this embodiment may be applied not only to the first embodiment described above, but also to, for example, the second to seventh embodiments.

[0123] <<12. Tenth Embodiment>> Next, the detailed configuration of the photonic crystal structure 140 according to the tenth embodiment of the present disclosure will be described with reference to Figures 12A to 12C. Figures 12A to 12C are schematic diagrams showing an example of the cross-sectional configuration of the photonic crystal structure 140 according to this embodiment, and correspond to the cross-section when the photonic crystal structure 140 is cut parallel to the plane of the substrate 110. In the following description, the explanation of points common to the first embodiment described above will be omitted.

[0124] In the embodiments of this disclosure described so far, an example has been described in which a single defect 146 is introduced into the photonic crystal structure 140, but this disclosure is not limited to this. Therefore, in the tenth embodiment, various modifications of the photonic crystal structure 140 will be described.

[0125] As shown in Figure 12A, there may be multiple defects 146 introduced into the photonic crystal structure 140. For example, in the example shown on the left side of Figure 12A, two defects 146 are introduced; in the example shown in the center of Figure 12A, three defects 146 are introduced; and in the example shown on the right side of Figure 12A, seven defects 146 are introduced. In this embodiment, the number of defects 146 introduced may differ for each light-emitting element 100, and may also differ for each color of light emitted by the light-emitting element 100. Furthermore, in this embodiment, the number of defects 146 introduced may be changed depending on the position of the light-emitting element 100 in the display panel 40. However, in all examples, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148, which includes the defects 146 and the region surrounding the defects 146.

[0126] In the example shown in Figure 12A, the multiple defects 146 introduced into the photonic crystal structure 140 were evenly (symmetrically) arranged within the photonic crystal structure 140. However, in this embodiment, as shown in Figure 12B, the defects 146 introduced into the photonic crystal structure 140 do not have to be evenly (symmetrically) arranged within the photonic crystal structure 140. For example, in the example shown on the left side of Figure 12B, three defects 146 are introduced, and these defects 146 are not positioned point-symmetrically with respect to the center of the photonic crystal structure 140. Also, in the example shown on the right side of Figure 12B, three defects 146 are introduced, and all of these defects 146 are positioned above the center of the photonic crystal structure 140. In this embodiment, the positions of the introduced defects 146 may differ for each light-emitting element 100, and may differ for each color of light emitted by the light-emitting element 100. Furthermore, in this embodiment, the positions of the introduced defects 146 may be changed according to the position of the light-emitting element 100 in the display panel 40. However, in all examples, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148, which includes the defect 146 and the region surrounding the defect 146.

[0127] In the examples shown in Figures 12A and 12B, the resonator region 148, which includes the defect 146 introduced into the photonic crystal structure 140, was circular in shape. However, in this embodiment, as shown in Figure 12C, the resonator region 148, which includes the defect 146 introduced into the photonic crystal structure 140, may have other shapes, for example, it may be elliptical. In this embodiment, the shape and size of the resonator region 148 may differ for each light-emitting element 100, and may also differ for each color of light emitted by the light-emitting element 100. Furthermore, in this embodiment, the shape and size of the introduced defect 146 may be changed according to the position of the light-emitting element 100 on the display panel 40. In this embodiment, the shape and size of the resonator region 148 are adjusted according to the desired color (wavelength) of light. However, in all examples, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148, which includes the defect 146 and the region surrounding the defect 146.

[0128] In this embodiment, the photonic crystal structure 140 is not limited to the form shown in Figures 12A to 12C, but can be further modified into various forms. Furthermore, the photonic crystal structure 140 according to this embodiment may be applied not only to the first embodiment described above, but also to, for example, the second to ninth embodiments.

[0129] <<13. Eleventh Embodiment>> Next, the detailed configuration of the display device 10 according to the eleventh embodiment of the present disclosure will be described with reference to Figures 13A and 13B. Figure 13A is a schematic diagram showing an example of the cross-sectional configuration of the display panel 40 according to the embodiment, and corresponds to the cross-section when the display panel 40 is cut along the line A-A' shown in Figure 13B. Figure 13B is a schematic diagram showing an example of the cross-sectional configuration of the photonic crystal structure 140 in the display panel 40 of this embodiment. In this embodiment, the light-emitting layer 152 includes a laminate of a plurality of organic light-emitting layers that emit red, blue, and green light, and emits white light.

[0130] In the display panel 40 of the display device 10 according to this embodiment, as shown in Figure 13A, a light-emitting element 100r that emits red light, a light-emitting element 100g that emits green light, and a light-emitting element 100b that emits blue light are arranged in a matrix on the substrate 110, with the light emitting red light and the light emitting upward.

[0131] As shown in Figure 13A, each light-emitting element 100 according to this embodiment has a laminated structure in which a reflective layer 120, a low-reflectance layer 122, a low-refractive-index layer 130, a photonic crystal structure 140, a lower electrode 150, a light-emitting layer 152, an upper electrode 154, a sealing film 200, a planarization film 202, a color filter 210, an on-chip lens 220, a sealing film 230, and a counter substrate 240 are sequentially stacked on a substrate 110. Details of each element of the light-emitting element 100 according to this embodiment will be described below, but points common to the first embodiment described above will be omitted from the explanation.

[0132] (Substrate 110) The substrate 110 may include a plug 112 electrically connected to the lower electrode 150. The plug 112 penetrates the photonic crystal structure 140, the low refractive index layer 130, and the substrate 110, and can electrically connect the lower electrode 150 to the back surface of the substrate 110. Wiring and the like may also be formed on the substrate 110 as appropriate.

[0133] (Reflective layer 120 / Low-reflective layer 122) In this embodiment as well, as shown in Figure 13A, the reflective layer 120 is provided so as to overlap with at least a portion of the resonator region 148, which includes the defects 146 of the photonic crystal structure 140 and the region surrounding the defects 146. Furthermore, in this embodiment as well, as shown in Figure 13A, a low-reflective layer 122 is provided around the reflective layer 120 on the substrate 110.

[0134] (Photonic crystal structure 140) In this embodiment, the photonic crystal structure 140 is provided in each of the light-emitting elements 100. In this embodiment, as shown in Figure 13B, the photonic crystal structure 140 has, for example, a hexagonal shape and a structure in which a plurality of columnar bodies 144 are arranged periodically, as well as defects 146.

[0135] (Lower electrode 150) In this embodiment, as shown in Figure 13A, the lower electrode 150 is provided separated for each light-emitting element 100.

[0136] (Light-emitting layer 152) As previously described, the light-emitting layer 152 has a structure in which, for example, a hole injection layer, a hole transport layer, a laminate of multiple organic light-emitting layers that emit red, blue, and green light, and an electron transport layer are sequentially stacked from bottom to top. The laminate can emit white light. In this embodiment, as shown in Figure 13A, the light-emitting layer 152 is provided to extend across multiple light-emitting elements 100.

[0137] (Upper electrode 154) In this embodiment, as shown in Figure 13A, the upper electrode 154 is provided to extend across a plurality of light-emitting elements 100. In other words, the upper electrode 154 is provided to electrically connect the upper electrodes 154 of adjacent light-emitting elements 100.

[0138] (Sealing films 200, 230) The sealing films 200 and 230 are provided to suppress damage to the light-emitting layer 152 and the like during the manufacturing process and contamination from the external environment. Preferably, the sealing films 200 and 230 are formed from an organic material that has low hygroscopicity and light transmittance to visible light. The sealing films 200 and 230 may have a single-layer structure or a multi-layer structure. Examples of organic materials include thermosetting resins and photosensitive resins. Photosensitive resins include, for example, ultraviolet-curable resins. Specifically, examples of organic materials include acrylic resins, polyimide resins, novolac resins, epoxy resins, and the like.

[0139] (Planarization film 202) The planarization film 202 is, for example, silicon oxide, aluminum oxide (AlO ｘ It can be formed from an oxide film such as ) or a resin film.

[0140] (Color Filter 210) As shown in Figure 13A, the color filter 210 is provided for each light-emitting element 100, for example. In this embodiment, the color filter 210 may be provided across multiple light-emitting elements 100. Each color filter 210 consists of, for example, a color filter 210r that transmits red wavelength components, a color filter 210g that transmits green wavelength components, or a color filter 210b that transmits blue wavelength components. The color filter 210 can also be formed from a material in which a pigment or dye is dispersed in a transparent binder such as silicone.

[0141] In this embodiment, light having a predetermined wavelength is confined and resonated in the resonator (resonator region 148) of the photonic crystal structure 140. Therefore, in this embodiment, the light-emitting element 100 can emit light of a desired color even without a color filter 210. However, in regions other than the resonator region 148, it is difficult to restrict the wavelength of light to a desired wavelength, so the light-emitting element 100 may emit light of a color other than the desired color. Furthermore, the color of the light emitted by the light-emitting element 100 may change due to deterioration of the organic light-emitting layer contained in the light-emitting layer 152, etc. Therefore, in this embodiment, it is preferable to provide a color filter 210 in order to more reliably ensure that the light-emitting element 100 emits light of a desired color.

[0142] (On-chip lens 220) As shown in Figure 13A, the on-chip lens 220 is provided for each light-emitting element 100, for example. In this embodiment, the on-chip lens 220 may be provided across multiple light-emitting elements 100. The on-chip lens 220 can be formed from, for example, a styrene resin, an acrylic resin, a styrene-acrylic copolymer resin, or a siloxane resin. The on-chip lens 220 can emit collimated light towards the upper front of the light-emitting element 100 or diagonally above the light-emitting element 100.

[0143] In this embodiment, the lens structure is not limited to the on-chip lens 220, and a lens structure capable of guiding light in a desired direction may be used. Examples of such lens structures include metasurfaces and waveguides. Here, a metasurface refers to a structure in which structures smaller than the wavelength of light are periodically arranged in two dimensions, and can be formed from, for example, metal or dielectric material. Furthermore, when using a metasurface, the metasurface is not limited to being provided for each light-emitting element 100, but may be provided so as to span multiple light-emitting elements 100.

[0144] (Opposite substrate 240) The opposite substrate 240 is a light-transmitting substrate that transmits light, and is made of, for example, a glass substrate or a transparent resin substrate (polyethylene terephthalate, acrylic resin, polycarbonate, polyolefin, etc.).

[0145] In this embodiment, the display device 10 is not limited to the form shown in Figures 13A and 13B, but can be transformed into various forms. In addition, the display device 10 according to this embodiment can be fitted with, for example, the light-emitting elements 100 of the second to eighth embodiments and the tenth embodiment, in addition to the light-emitting elements 100 of the first embodiment described above.

[0146] <<14. Twelfth Embodiment>> Next, the detailed configuration of the display device 10 according to the twelfth embodiment of the present disclosure will be described with reference to Figures 14A and 14B. Figure 14A is a schematic diagram showing an example of the cross-sectional configuration of the display panel 40 according to the embodiment, and corresponds to the cross-section when the display panel 40 is cut along the line A-A' shown in Figure 14B. Figure 14B is a schematic diagram showing an example of the cross-sectional configuration of the photonic crystal structure 140 in the display panel 40 of this embodiment. In this embodiment, the display device 10 has a light-emitting element 100 including a light-emitting layer 300 made of an infinite light-emitting layer.

[0147] In the display panel 40 of the display device 10 according to this embodiment, as shown in Figure 14A, a light-emitting element 100r that emits red light, a light-emitting element 100g that emits green light, and a light-emitting element 100b that emits blue light are arranged in a matrix on the substrate 110, with the light emitting red light and the light emitting upward.

[0148] As shown in Figure 14A, each light-emitting element 100 according to this embodiment has a laminated structure in which a reflective layer 120, a low-reflectance layer 122, a low-refractive-index layer 130, a photonic crystal structure 140, a lower electrode 150, a light-emitting layer 300, an upper electrode 154, an on-chip lens 220, a sealing film 230, and a counter substrate 240 are sequentially stacked on a substrate 110. Details of each element of the light-emitting element 100 according to this embodiment will be described below, but the explanation of points common to the first and thirteenth embodiments described above will be omitted.

[0149] (Reflector 120 / Low-reflection layer 122) In this embodiment as well, as shown in Figure 14A, the reflective layer 120 is provided so as to overlap at least a portion of the resonator region 148, which includes the defect 146 of the photonic crystal structure 140 and the region surrounding the defect 146. Furthermore, in this embodiment as well, as shown in Figure 14A, a low-reflection layer 122 is provided around the reflective layer 120 on the substrate 110.

[0150] (Photonic crystal structure 140) In this embodiment, the photonic crystal structure 140 is provided in each of the light-emitting elements 100. In this embodiment, as shown in Figure 14B, the photonic crystal structure 140 is, for example, octagonal in shape and has a structure in which a plurality of columnar bodies 144 are arranged periodically, as well as defects 146.

[0151] (Lower electrode 150) In this embodiment, as shown in Figure 14A, the lower electrode 150 is provided separated for each light-emitting element 100.

[0152] (Light-emitting layer 300) In this embodiment, as shown in Figure 14A, a light-emitting layer 300 is provided individually for each light-emitting element 100. Each light-emitting layer 300 is formed from an inorganic light-emitting layer that emits red, blue, and green light.

[0153] In detail, the light-emitting layer 300 has a laminated light-emitting structure consisting of, for example, a compound semiconductor layer 302, an active layer 304, and a compound semiconductor layer 306, as shown in Figure 14A. The laminated light-emitting structure, in which the compound semiconductor layer 302, the active layer 304, and the compound semiconductor layer 306 are stacked, can be made of, for example, a GaN-based compound semiconductor, an AlGaInAs-based compound semiconductor, an AlGaInP-based compound semiconductor, a ZnSe-based compound semiconductor, or a ZnO-based compound semiconductor.

[0154] In this embodiment, the active layer 304 may have a quantum well structure. Specifically, the active layer 304 may have a single quantum well structure (SQW structure) or a multiple quantum well structure (MQW structure). Furthermore, the compound semiconductor layer 302 may be composed of a compound semiconductor of a first conductivity type (e.g., n-type), and the compound semiconductor layer 306 may be composed of a compound semiconductor of a second conductivity type (e.g., p-type) different from the first conductivity type.

[0155] (Upper electrode 154) In this embodiment, as shown in Figure 14A, the upper electrode 154 is provided to extend across a plurality of light-emitting elements 100. In other words, the upper electrode 154 is provided to electrically connect the upper electrodes 154 of adjacent light-emitting elements 100.

[0156] (White plate 310) In this embodiment, the side walls of the light-emitting layer 300 are covered by the white plate 310. By covering the side walls of the light-emitting layer 300, the white plate 310 prevents light from the light-emitting layer 300 from leaking out in a direction perpendicular to the stacking direction of the light-emitting layer 300.

[0157] In this embodiment, the display device 10 is not limited to the form shown in Figures 14A and 14B, but can be transformed into various forms. In addition, the display device 10 according to this embodiment can be fitted with, for example, the light-emitting elements 100 according to the second to tenth embodiments, in addition to the light-emitting elements 100 according to the first embodiment described above.

[0158] <<15. Manufacturing Method>> Next, an example of a manufacturing method for the light-emitting element 100 according to the first embodiment described above will be explained with reference to Figures 15A to 15C. Figures 15A to 15C are schematic diagrams showing the manufacturing process of the light-emitting element 100 according to the first embodiment of this disclosure, and correspond to the cross-section of the light-emitting element 100 in Figure 3A.

[0159] First, as shown in the upper part of Figure 15A, a reflective layer 120 made of, for example, an AlCu alloy is deposited on a substrate 110 made of, for example, silicon, by sputtering or the like. Next, as shown in the middle part of Figure 15A, the deposited reflective layer 120 is patterned so as to overlap with the resonator region 148 of the photonic crystal structure 140. Furthermore, as shown in the lower part of Figure 15A, a resist film 410 is formed on the patterned reflective layer 120 to protect the reflective layer 120.

[0160] Then, as shown in the upper part of Figure 15B, a low-reflection layer 122, for example, made of a black matrix, is applied to cover the entire substrate 110. Next, as shown in the middle part of Figure 15B, the low-reflection layer 122 is formed around the reflective layer 120 by removing the resist film 410. Furthermore, as shown in the lower part of Figure 15B, a low-refractive-index layer 130, for example, made of silicon oxide, is deposited by the CVD (Chemical Vapor Deposition) method.

[0161] Then, as shown in the upper part of Figure 15C, SiN is added to the low refractive index layer 130, for example, by CVD. ｘ A photonic crystal layer 142 is formed from the above material. Next, as shown in the middle of Figure 15C, a plurality of holes are formed in the photonic crystal layer 142 using, for example, EB (Electron Beam) exposure or lithography, and HSQ is embedded in the holes. Furthermore, as shown in the lower part of Figure 15C, a lower electrode 150 made of, for example, ITO, a light-emitting layer 152 made of an organic material, and an upper electrode 154 made of ITO are sequentially stacked. For example, the lower electrode 150 and the upper electrode 154 can be formed by sputtering, and the light-emitting layer 152 can be formed by vapor deposition. In this way, a light-emitting element 100 according to the first embodiment can be obtained.

[0162] 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.

[0163] Examples of the methods mentioned above include PVD (Physical Vapor Deposition), CVD, and ALD (Atomic Layer Deposition). PVD methods include vacuum deposition, EB (electron beam) deposition, various sputtering methods (magnetron sputtering, RF (Radio Frequency)-DC (Direct Current) coupled bias sputtering, ECR (Electron Cyclotron Resonance) sputtering, opposing target sputtering, high-frequency sputtering, etc.), ion plating, laser ablation, molecular beam epitaxy (MBE (Molecular Beam Epitaxy)), and laser transfer. Furthermore, CVD methods include plasma CVD, thermal CVD, metal-organic (MO) CVD, and photo-CVD. 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. Patterning methods include chemical etching such as shadow masks, laser transfer, and photolithography, as well as physical etching using ultraviolet light or lasers. In addition, planarization techniques include CMP (Chemical Mechanical Polishing), laser planarization, and reflow.

[0164] <<16. Summary>> As described above, in each embodiment of this disclosure, the optical path control layer is provided so as to overlap with at least a part of the resonator region 148 of the photonic crystal structure 140. In this way, in this embodiment, it is possible to more efficiently reflect light from the resonator region 148 while suppressing the reflection of ambient light. As a result, in this embodiment, it is possible to avoid a decrease in visibility due to ambient light reflection without using a circular deflection plate. Furthermore, according to this embodiment, since the brightness is increased by the optical resonance of the photonic crystal structure 140 in which defects have been introduced, it does not lead to an increase in the power consumption of the display device 10 or a decrease in the product lifespan.

[0165] 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.

[0166] <<17. Modifications>> <17.1 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 220 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 210 provided on the light-emitting element 100) will be described with reference to Figures 16A to 16G. Figures 16A to 16G 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.

[0167] 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.

[0168] For example, as shown in Figure 16A, 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).

[0169] Furthermore, for example, as shown in Figure 16B, 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.

[0170] Furthermore, for example, as shown in Figure 16C, 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.

[0171] Furthermore, as shown in Figure 16D, 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 16D) 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 16D). 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.

[0172] 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 16E, 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.

[0173] Furthermore, for example, as shown in Figure 16F, 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.

[0174] Furthermore, as shown in the conceptual diagram Figure 16G, 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 16G) 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 16G) 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.

[0175] <17.2 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 152. The above resonator structure will be described below with reference to Figures 17 to 23. Figure 17 is a schematic cross-sectional view illustrating a first example of the resonator structure, Figure 18 is a schematic cross-sectional view illustrating a second example of the resonator structure, and Figure 19 is a schematic cross-sectional view illustrating a third example of the resonator structure. Furthermore, Figure 20 is a schematic cross-sectional view illustrating a fourth example of the resonator structure, and Figure 21 is a schematic cross-sectional view illustrating a fifth example of the resonator structure. Furthermore, Figure 22 is a schematic cross-sectional view illustrating a sixth example of the resonator structure, and Figure 23 is a schematic cross-sectional view illustrating a seventh example of the resonator structure.

[0176] (Resonator Structure: First Example) Figure 17 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 150) 1202 is formed with a common film thickness in each subpixel 1100. The same applies to the second electrode (specifically, the upper electrode 154) 1206.

[0177] As shown in Figure 17, 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 152) 1204 to resonate.

[0178] 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.

[0179] In the example shown in Figure 17, 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.

[0180] 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.

[0181] The optical adjustment layer 1402 is made of silicon nitride (SiN ｘ ), silicon oxide (SiO ｘ ), silicon oxynitride (SiO ｘ N ｙIt can be constructed using inorganic insulating materials such as ) or organic resin materials such as acrylic resins or polyimide resins. The optical adjustment layer 1402 may be a single layer or a laminated film of multiple materials. Also, the number of layers may differ depending on the type of subpixel 1100.

[0182] 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).

[0183] 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.

[0184] (Resonator structure: Second example) Figure 18 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.

[0185] 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.

[0186] In the first example shown in Figure 17, 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.

[0187] In contrast, in the second example shown in Figure 18, 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.

[0188] 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.

[0189] (Resonator structure: Third example) Figure 19 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.

[0190] 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.

[0191] In the second example shown in Figure 18, 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.

[0192] In contrast, in the third example shown in Figure 19, 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.

[0193] 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.

[0194] (Resonator structure: 4th example) Figure 20 is a schematic cross-sectional view illustrating the 4th example of a resonator structure.

[0195] In the first example shown in Figure 17, 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.

[0196] In contrast, in the fourth example shown in Figure 20, 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.

[0197] 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.

[0198] 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.

[0199] (Resonator structure: Fifth example) Figure 21 is a schematic cross-sectional view illustrating the fifth example of a resonator structure.

[0200] In the first example shown in Figure 17, 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.

[0201] In contrast, in the fifth example shown in Figure 21, 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.

[0202] 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.

[0203] 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.

[0204] 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.

[0205] 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.

[0206] 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.

[0207] 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.

[0208] (Resonator Structure: Sixth Example) Figure 22 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.

[0209] 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.

[0210] 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.

[0211] (Resonator Structure: Seventh Example) Figure 23 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.

[0212] 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.

[0213] 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.

[0214] <<18. 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.

[0215] (Specific Example 1) Figure 24A is a front view showing an example of the external appearance of the digital still camera 500, and Figure 24B 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.

[0216] 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.

[0217] (Specific Example 2) Figure 25 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.

[0218] (Specific Example 3) Figure 26 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.

[0219] 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.

[0220] 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.

[0221] 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.

[0222] (Specific Example 4) Figure 27 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.

[0223] (Specific Example 5) Figure 28 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.

[0224] (Specific Example 6) Figures 29A and 29B show the internal configuration of an automobile having a display device 10 according to the present disclosure as a display device. More specifically, Figure 29A shows the interior of the automobile from the rear to the front, and Figure 29B shows the interior of the automobile from the diagonally rear to the diagonally front.

[0225] The automobile shown in Figures 29A and 29B 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.

[0226] The center display 911 is positioned on the center console 907, facing the driver's seat 901 and the passenger seat 902. Figures 29A and 29B 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 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.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] 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.

[0231] 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.

[0232] 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).

[0233] <<19. Supplement>> 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 idea described in the claims, and these will naturally also be understood to fall within the technical scope of the present disclosure.

[0234] 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.

[0235] Furthermore, this technology can also take the following configurations: (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 photonic crystal structure including a periodic structure and one or more defects that disrupt the periodic structure and which acts on light from the emitting layer; and an optical path control layer which acts to direct the path of light upwards toward the light-emitting element, wherein when the light-emitting element is viewed from above, the optical path control layer is provided to overlap with at least a portion of a resonator including the defects of the first photonic crystal structure and the region surrounding the defects. (2) The display device according to (1) above, wherein when the light-emitting element is viewed from above, the optical path control layer is smaller than the size of the light-emitting element. (3) The display device according to (1) or (2) above, wherein when the light-emitting element is viewed from above, the optical path control layer does not overlap with the outer periphery of the first photonic crystal structure. (4) The display device according to any one of (1) to (3) above, wherein when the light-emitting element is viewed from above, the optical path control layer is superimposed on the entire resonator. (5) The display device according to any one of (1) to (4) above, wherein the optical path control layer is made of a reflective layer. (6) The display device according to (5) above, wherein the optical path control layer is made of a retroreflective layer. (7) The display device according to (6) above, wherein the retroreflective layer includes transparent beads or a corner cube structure. (8) The display device according to any one of (1) to (4) above, wherein each light-emitting element further comprises a second photonic crystal structure including a periodic structure and one or more defects that disrupt the periodic structure, and the optical path control layer comprises a resonator including the defects of the second photonic crystal structure and the region around the defects. (9) The display device according to (8), wherein the second photonic crystal structure includes a plurality of periodically arranged columnar bodies, and a portion of the plurality of columnar bodies away from the defect is made of a low-reflectivity material. (10) The display device according to any one of (1) to (7), wherein a low-reflectivity layer is provided around the optical path control layer.(11) The display device according to any one of (1) to (7) above, wherein a light transmission layer that selectively transmits light of a predetermined wavelength, or a color conversion layer that converts the wavelength of light, is provided around the light path control layer. (12) The display device according to (11) above, wherein the light transmission layer transmits light having the same wavelength as the light emitted from the light-emitting layer of the light-emitting element. (13) The display device according to any one of (1) to (12) above, wherein a low refractive index layer is provided on the light path control layer, and the first photonic crystal structure is provided on the low refractive index layer. (14) The display device according to any one of (1) to (13) above, wherein the first photonic crystal structure is a three-dimensional photonic crystal structure. (15) The display device according to (13) above, wherein the first photonic crystal structure is a two-dimensional slab-type photonic crystal structure. (16) The display device according to (15), wherein the first photonic crystal structure includes a plurality of periodically arranged columnar bodies, the plurality of columnar bodies penetrating at least a portion of the low refractive index layer. (17) The display device according to any one of (1) to (13), wherein the first photonic crystal structure is provided in the light-emitting layer. (18) The display device according to (17), wherein the light-emitting layer is made of an inorganic material. (19) The display device according to any one of (1) to (12), wherein a low refractive index layer is provided on the optical path control layer, the light-emitting layer is provided on the low refractive index layer, and the first photonic crystal structure is provided on the light-emitting layer. (20) The display device according to any one of (1) to (16), wherein the light-emitting layer is made of an organic material.

[0236] 10 Display device 11 Horizontal drive circuit 12 Vertical drive circuit 20 Pixel array section 40 Display panel 100, 100b, 100g, 100r Light-emitting element 110 Substrate 112 Plug 120 Reflective layer 122 Low-reflection layer 124 Light-transmitting layer 126 Retroreflective layer 130 Low refractive index layer 140, 140a, 140b, 140c, 140d Photonic crystal structure 142 Photonic crystal layer 144, 144a Columnar body 146 Defect 148, 148a Resonator region 150 Lower electrode 152, 300 Light-emitting layer 154 Upper electrode 160 Substrate 162, 162a Bead 164 Coating film 166, 170 Corner cube structure 200, 230 Encapsulation film 202 Planarization film 210, 210b, 210g, 210r Color filter 220 On-chip lens 240 Opposing substrate 302, 306 Compound semiconductor layer 304 Active layer 310 White plate 400, 400B, 400G, 400R Subpixel 410 Resist film

Claims

1. A display device having a plurality of light-emitting elements arranged on a substrate, wherein each light-emitting element comprises: a light-emitting layer; a first photonic crystal structure having a periodic structure and one or more defects that disrupt the periodic structure, and acting on light from the light-emitting layer; and a light path control layer acting to direct the path of light upwards toward the light-emitting element, wherein, when the light-emitting element is viewed from above, the light path control layer is provided to overlap with at least a portion of a resonator including the defects of the first photonic crystal structure and the region surrounding the defects.

2. The display device according to claim 1, wherein, when the light-emitting element is viewed from above, the optical path control layer is smaller than the size of the light-emitting element.

3. The display device according to claim 1, wherein, when the light-emitting element is viewed from above, the optical path control layer does not overlap with the outer periphery of the first photonic crystal structure.

4. The display device according to claim 1, wherein, when the light-emitting element is viewed from above, the optical path control layer is superimposed on the entire resonator.

5. The display device according to claim 1, wherein the optical path control layer comprises a reflective layer.

6. The display device according to claim 5, wherein the optical path control layer comprises a retroreflective layer.

7. The display device according to claim 6, wherein the retroreflective layer includes transparent beads or a corner cube structure.

8. The display device according to claim 1, wherein each light-emitting element further comprises a second photonic crystal structure having a periodic structure and one or more defects that disrupt the periodic structure, and the optical path control layer comprises a resonator including the defects of the second photonic crystal structure and the region surrounding the defects.

9. The display device according to claim 8, wherein the second photonic crystal structure comprises a plurality of periodically arranged columnar bodies, and a portion of the plurality of columnar bodies away from the defects is made of a low-reflectivity material.

10. The display device according to claim 1, wherein a low-reflection layer is provided around the optical path control layer.

11. The display device according to claim 1, wherein a light transmission layer that selectively transmits light of a predetermined wavelength, or a color conversion layer that converts the wavelength of light, is provided around the light path control layer.

12. The display device according to claim 11, wherein the light-transmitting layer transmits light having the same wavelength as the light-emitting layer of the light-emitting element.

13. The display device according to claim 1, wherein a low refractive index layer is provided on the optical path control layer, and the first photonic crystal structure is provided on the low refractive index layer.

14. The display device according to claim 1, wherein the first photonic crystal structure is a three-dimensional photonic crystal structure.

15. The display device according to claim 13, wherein the first photonic crystal structure is a two-dimensional slab-type photonic crystal structure.

16. The display device according to claim 15, wherein the first photonic crystal structure includes a plurality of periodically arranged columnar bodies, and the plurality of columnar bodies penetrate at least a portion of the low refractive index layer.

17. The display device according to claim 1, wherein the first photonic crystal structure is provided in the light-emitting layer.

18. The display device according to claim 17, wherein the light-emitting layer is made of an inorganic material.

19. The display device according to claim 1, wherein a low refractive index layer is provided on the optical path control layer, the light-emitting layer is provided on the low refractive index layer, and the first photonic crystal structure is provided on the light-emitting layer.

20. The display device according to claim 1, wherein the light-emitting layer is made of an organic material.

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