Display device

Abstract

Provided is a display device having a plurality of light-emitting elements (100) arranged on a substrate (102), wherein each of the light-emitting elements is provided with a light-emitting layer (114), a resonator structure (200) provided in the light-emitting layer or in the vicinity of the light-emitting layer and configured to resonate light having a prescribed wavelength from light emitted from the light-emitting layer, and a reflection plate (104) provided below the resonator structure. The reflection plate and the resonator structure are disposed such that, in the resonator structure, the light having the prescribed wavelength and reflected by the reflection plate and the light having the prescribed wavelength and resonated by the resonator structure interfere with and strengthen each other.

Description

display device

[0001] This disclosure relates to a display device.

[0002] In recent years, the development of display devices using self-luminescent elements such as electroluminescent (EL) elements has progressed. In such display devices, for example, multiple light-emitting elements having a stacked structure composed of a lower electrode, a light-emitting layer stacked on the lower electrode, and an upper electrode stacked on the light-emitting layer are arranged on a substrate. When a predetermined voltage is supplied to the lower electrode and the upper electrode, the light-emitting layer sandwiched between the lower electrode and the upper electrode emits light. For example, one example of such a display device is the display device described in Patent Document 1 below.

[0003] Japanese Patent Publication No. 2022-81426

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

[0005] Therefore, in display devices, the frontal radiation intensity of light is increased by guiding the light from the light-emitting element to the upper front of the display surface of the display device by providing an on-chip lens or the like on the light-emitting element. However, in conventional display devices, most of the emitted light does not reach the on-chip lens. Consequently, it has been difficult to further increase the frontal radiation intensity of light from the display device in conventional technology.

[0006] This disclosure proposes a display device capable of increasing the frontal radiation intensity of light.

[0007] According to this disclosure, a display device is provided having a plurality of light-emitting elements arranged on a substrate, wherein each light-emitting element comprises a light-emitting layer, a resonator structure provided in or near the light-emitting layer and resonating with light of a predetermined wavelength from the light-emitting layer, and a reflector provided below the resonator structure, wherein the reflector and the resonator structure are arranged such that, in the resonator structure, the light of the predetermined wavelength reflected by the reflector and the light of the predetermined wavelength resonated in the resonator structure interfere with and reinforce each other.

[0008] 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 a comparative example. This is a schematic diagram (1) showing an example of the cross-sectional configuration of a light-emitting element according to an embodiment of this disclosure. This is a schematic diagram (2) showing an example of the cross-sectional configuration of a light-emitting element according to an embodiment of this disclosure. This is an explanatory diagram for explaining embodiments of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a light-emitting element according to the first embodiment of this disclosure. This is a schematic diagram showing an example of the cross-sectional configuration of a 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 conceptual diagram (1) for explaining the relationship between the normal LN passing through the center of the light-emitting part, the normal LN' passing through the center of the lens member, and the normal LN'' passing through the center of the wavelength selection part. This is a conceptual diagram (2) for explaining the relationship between the normal LN passing through the center of the light-emitting part, the normal LN' passing through the center of the lens member, and the normal LN'' passing through the center of the wavelength selection part. This is a conceptual diagram (part 3) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (part 4) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (part 5) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (part 6) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN" passing through the center of the wavelength-selecting part. This is a conceptual diagram (No. 7) illustrating the relationship between the normal vector LN passing through the center of the light-emitting part, the normal vector LN' passing through the center of the lens member, and the normal vector LN'' passing through the center of the wavelength-selecting part. This is a schematic cross-sectional view illustrating the first example of the resonator structure. This is a schematic cross-sectional view illustrating the second example of the resonator structure. This is a schematic cross-sectional view illustrating the third example of the resonator structure. This is a schematic cross-sectional view illustrating the fourth example of the resonator structure. This is a schematic cross-sectional view illustrating the fifth example of the resonator structure. This is a schematic cross-sectional view illustrating the sixth example of the 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 (1) showing the internal configuration of an automobile. This is a diagram (2) showing the internal configuration of an automobile.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] The explanation will proceed in the following order: 1. Display device according to the embodiment of this disclosure 1.1 Display device 1.2 Pixel 2. Background and overview 3. First embodiment 4. Second embodiment 5. Third embodiment 6. Summary 7. Modifications 7.1 Modification 1 7.2 Modification 2 8. Application examples 9. Supplement

[0013] <<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.

[0014] The display device 10 is a device that forms an array of light-emitting elements such as OLEDs (Organic Light Emitting Diodes) or Micro-OLEDs. 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. In addition, the display device 10 may use light-emitting elements made of inorganic materials instead of organic materials such as OLEDs.

[0015] Furthermore, in the embodiments of this disclosure, the light-emitting element may be a self-emissive element as well as a current-driven electro-optic element. For example, in addition to OLEDs, current-driven electro-optic elements include inorganic EL elements, LED elements, semiconductor laser elements, etc. Furthermore, an organic EL display device using an OLED as the light-emitting element has the following features. Specifically, because the OLED is a self-emissive element, the organic EL display device has higher image visibility compared to liquid crystal display devices, which are also planar display devices, and is easy to make lighter and thinner because it does not require lighting members such as backlights. Moreover, because the response speed of OLED is very fast, on the order of a few microseconds, the organic EL display device does not produce afterimages when displaying moving images.

[0016] Here, as an example, we will explain using an active-matrix organic EL display device that uses a current-driven light-emitting element, such as an OLED, which changes its luminescence depending on the current flowing through the device, as the light-emitting element. Hereafter, "active-matrix organic EL display device" will simply be referred to as "display device".

[0017] 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.

[0018] 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, configure a pixel by adding a subpixel 400 that emits white light to improve brightness, or configure a pixel by adding at least one subpixel 400 that emits complementary color light to expand the color reproduction range.

[0019] 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.

[0020] 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 each scan line SCL ｍ Scanning signals can be supplied sequentially. 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 pulses.

[0021] Further, the vertical drive circuit 12 supplies the signal voltage of a signal corresponding to the luminance information supplied from a signal supply source (not shown) to the sub-pixels 400 selected in column units (in FIG. 1, the direction extending along the Y direction is called the column direction) via the signal line DTL. ｎ can be supplied.

[0022] In the embodiment of the present disclosure, the configuration of the display device 10 is not limited to the configuration shown in FIG. 1. That is, the configuration shown in FIG. 1 is merely an example, and various configurations can be adopted in the display device 10 according to the embodiment of the present disclosure.

[0023] <1.2 Pixel> Next, the circuit configuration of the sub-pixel 400 of the display device 10 according to the embodiment of the present disclosure shown in FIG. 1 will be described. FIG. 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, is a schematic circuit diagram for explaining the connection relationship in the sub-pixel 400 at the m-th row and n-th column.

[0024] In the display device 10, as described above, the sub-pixel 400 including the light-emitting element 100 is arranged in a two-dimensional matrix in a state of being connected to the scanning line SCL extending in the row direction (X direction in FIG. 1) ｍ and the signal line DTL extending in the column direction (Y direction in FIG. 1). ｎ [[ID=‎17]]

[0025] Further, as shown in FIG. 2, the display device 10 has a power supply line PS1 that supplies a drive voltage to the sub-pixel 400 ｍ and a common power supply line PS2 that is commonly connected to all the sub-pixels 400. Then, a predetermined drive voltage V etc. is supplied to the power supply line PS1 ｍ from a power supply unit (not shown), and a common voltage V [[ID=2‎3]] ＣＣ (for example, ground potential) is supplied to the common power supply line PS2. Ｃａｔ

[0026] Here, let the number of the scanning lines SCL and the power supply lines PS1 be M each. The sub-pixel 400 in the m-th row (where m = 1, 2,..., P) is the m-th scanning line SCL ｍ and the m-th power supply line PS1. ｍIt is connected to and constitutes one row of display elements. Note that in Figure 2, the scan line SCL ｍ and power supply line PS1 ｍ Only is shown. Also, let the number of signal lines DTL be N. Subpixel 400 of the nth column (where n = 1, 2..., N) is the nth signal line DTL ｎ It is connected to the signal line DTL in Figure 2. ｎ Only the following is shown. Hereafter, the subpixel 400 located in the mth row and nth column may be referred to as the (n,m)th subpixel 400.

[0027] As explained earlier, the display device 10 is scanned sequentially row by row by the scanning signal from the horizontal drive circuit 11. More specifically, in the display device 10, M subpixels 400 arranged in the m-th row are driven simultaneously. In other words, for the M subpixels 400 arranged along the row direction, the timing of their illumination / de-illumination is controlled on a row-by-row basis. For example, if the display frame rate of the display device 10 is FR (frames / second), the scanning period per row (the so-called horizontal scanning period) when the display device 10 is scanned sequentially row by row will be less than (1 / FR) × (1 / P) seconds.

[0028] Furthermore, as shown in Figure 2, the sub-pixel 400 is composed of a light-emitting element 100 and a drive circuit that drives it. The light-emitting element 100 consists of an organic electroluminescent light-emitting element or an inorganic electroluminescent light-emitting element. The drive circuit is a writing transistor TR Ｗ , and drive transistor TR Ｄ , and also, capacity section C １ It consists of the following: drive transistor TR Ｄ When current flows through the light-emitting element 100, the light-emitting element 100 can emit light. Each transistor is composed of, for example, a p-channel type field-effect transistor.

[0029] As shown in Figure 2, in the sub-pixel 400, the drive transistor TR Ｄ One of the source / drain regions is the capacitance section C １ One end and power supply line PS1 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.

[0030] 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.

[0031] 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.

[0032] The overview of the driving of the sub-pixel 400 will be described. In the sub-pixel 400, the signal line DTL is transmitted from the vertical drive circuit 12. ｎ With a voltage corresponding to the brightness of the image to be displayed supplied, the writing transistor TR is activated by a scanning signal from the horizontal drive circuit 11. Ｗ When the capacitance C is in a conductive state, １ A voltage corresponding to the brightness is written to it. (Writing transistor TR) Ｗ After the capacitor is de-conducted, the capacitance part C 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.

[0033] 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.

[0034] <<2. Background and Overview>> Next, before describing the details of the embodiments of this disclosure, the background leading to the invention of the embodiments of this disclosure and an overview of the embodiments of this disclosure created by the inventors will be described with reference to Figures 3 to 6. Figure 3 is a schematic diagram showing an example of the cross-sectional configuration of a comparative example light-emitting element 100a. Figures 4 and 5 are schematic diagrams showing an example of the cross-sectional configuration of a light-emitting element 100 according to an embodiment of this disclosure, and Figure 6 is an explanatory diagram for explaining the embodiments of this disclosure. Here, a comparative example means a light-emitting element 100a that the inventors had been studying before creating the embodiments of this disclosure.

[0035] In the comparative example light-emitting element 100a, as shown in Figure 3, a reflector 104, a spacer layer 106, a lower electrode 110, a transport layer 112, a light-emitting layer 114, a transport layer 116, an upper electrode 118, a spacer layer 120, a color filter 130, and an on-chip lens 132 are sequentially stacked on the substrate 102 in this order.

[0036] In the light-emitting element 100a according to this comparative example, when a predetermined voltage is supplied to the lower electrode 110 and the upper electrode 118, the light-emitting layer 114 sandwiched between the lower electrode 110 and the upper electrode 118 emits light, causing the light-emitting element 100a to emit light.

[0037] Incidentally, the display device 10 described above can display high-quality and high-resolution images, and is therefore used not only in direct-view display devices such as monitors, but also in small display devices such as EVFs and HMDs. In recent years, in order to use these display devices particularly for VR and AR applications, there has been a strong demand for the display device 10 to have a higher frontal radiation intensity.

[0038] Therefore, the structure of the light-emitting element 100a mounted on the display device 10 is optimized so that the light extraction efficiency is improved for each color of light emitted from the light-emitting layer 114. In the comparative example, as one of the methods for such optimization, a microcavity structure is used to improve color reproducibility and light extraction efficiency.

[0039] In the comparative example, light from the light-emitting layer 114 is radiated upward towards the light-emitting element 100a, and the reflector 104 located below the light-emitting layer 114 reflects the light from the light-emitting layer 114, so that the reflected light is radiated upward towards the light-emitting element 100a. In the microcavity structure, for each light-emitting element 100a, for example, the distance between the reflector 104 and the upper electrode (reflective surface) 118 is optimized, and light of a predetermined wavelength from the light-emitting layer 114 is resonated between the reflector 104 and the upper electrode 118. In this way, in the comparative example, the intensity of the light radiated from the light-emitting element 100a can be increased.

[0040] Specifically, in a microcavity structure, for example, the optical distance L between the reflector 104 and the upper electrode 118. １ (See Figure 3) The emission peak wavelength of the light-emitting layer 114 (an example of a predetermined wavelength) λ ｐｅａｋ The following equation (1) is used to set the resonance conditions to be satisfied. In the following explanation, the wavelength of light is set to the emission peak wavelength λ of the light-emitting layer 114. ｐｅａｋ However, this is not the only option, and in this embodiment, the wavelength of light emitted from the light-emitting layer 114 can be arbitrarily selected. Furthermore, in this specification, "optical distance" refers to the effective wavelength and optical path length, taking into account the refractive index of materials such as multilayer structures and nanostructures.

[0041] In the above formula (1), λ ｐｅａｋ : Emission peak wavelength λ Φ: Phase shift due to reflection (radians) m: Any integer.

[0042] In the comparative example, the microcavity structure satisfies the resonance conditions shown in formula (1) above, causing light to resonate in the vertical direction and increasing the intensity of light from the light-emitting element 100a. Furthermore, in the comparative example, since the light from the light-emitting layer 114 is emitted in all directions from the light-emitting layer 114, the reflector 104 and the microcavity structure are used to control the propagation of the light upwards of the light-emitting element 100. Moreover, in the comparative example, the light controlled to propagate upwards of the light-emitting element 100 is emitted as collimated light in front of the light-emitting element 100a using the on-chip lens 132.

[0043] However, since most of the light emitted from the light-emitting layer 114 does not propagate upwards to the light-emitting element 100, it does not reach the on-chip lens 132 and instead becomes light energy in the waveguide mode that propagates laterally to the light-emitting element 100a. Furthermore, some of this light energy may be lost as thermal energy without being extracted as light from the light-emitting element 100a. In other words, in the light-emitting element 100a of the comparative example, it is difficult to control the direction of propagation of a large amount of light to the desired direction, and there is a limit to how much the luminous efficiency can be increased.

[0044] Therefore, the inventors devised a resonator structure 200, as described later, to extract the light emitted from the light-emitting layer 114 to the upper front of the light-emitting element 100, as shown in Figure 4. The resonator structure 200 confines the light from the light-emitting layer 114 in the lateral direction of the light-emitting element 100 and resonates it in the lateral direction, thereby increasing the intensity (brightness, color purity) of the light from the light-emitting element 100. Furthermore, by using the resonator structure 200, it is possible to confine the light in the lateral direction and extract the light in the resonant mode in the direction of the film thickness of the resonator structure 200, making it easy to control the direction of light propagation, that is, to extract the light in a highly directional state. In addition, of the light resonated in the resonator structure 200, the light that propagates downwards in the resonator structure 200 is reflected by the reflector 104 located below the resonator structure 200, allowing a large amount of light to propagate upwards in the light-emitting element 100 and reach the on-chip lens 132. In other words, the inventors have devised a light-emitting element 100 with high luminous efficiency that can obtain light with high directionality, brightness, and color purity.

[0045] Furthermore, in the embodiments of the present disclosure devised by the present inventors, the resonator structure 200 may be located in any layer within the light-emitting element 100, as long as it is above the reflector 104 or the lower electrode 110 having the function of the reflector 104. However, in order to receive and confine most of the light from the light-emitting layer 114, the resonator structure 200 is located above the peak wavelength λ of the light-emitting layer 114. ｐｅａｋ It is preferable to set it within a range of the length of the peak wavelength λ ｐｅａｋ It is more preferable to provide the resonator structure within a range of half the length. By doing so, the density of states of light near the light-emitting layer 114 changes due to the resonator structure 200, increasing the emission of resonant modes and allowing more light to propagate upwards to the light-emitting element 100. Furthermore, it is preferable that the resonator structure 200 be placed in the propagation path where a large amount of light from the light-emitting layer 114 is present. By doing so, the resonator structure 200 can extract a large amount of light with good directionality.

[0046] Furthermore, in embodiments of this disclosure, the resonator structure 200 may be provided across multiple layers of the light-emitting element 100, as will be described later. Moreover, it is preferable that the resonator structure 200 has a higher Q-factor than the microcavity structure described above. A higher Q-factor allows for a higher intensity of light at a predetermined wavelength.

[0047] Furthermore, after conducting further studies on a configuration in which the resonator structure 200 is introduced into the light-emitting element 100, the inventors discovered that by setting the distance between the resonator structure 200 and the reflector 104 to an appropriate distance, the intensity of light from the light-emitting element 100 can be further increased.

[0048] In detail, as shown in Figure 4, the optical distance L between the resonator structure 200 and the reflector 104 is... ２ In the resonator structure 200, the emission peak wavelength λ of the light-emitting layer 114 is reflected by the reflector 104. ｐｅａｋ Light having (an example of a predetermined wavelength) and the emission peak wavelength λ resonated in the resonator structure 200 ｐｅａｋ The system is optimized so that it interferes constructively with light having (an example of a predetermined wavelength).

[0049] In detail, the optical distance L between the resonator structure 200 and the reflector 104 in the stacking direction of the light-emitting element 100. ２ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ For a given wavelength, the following conditions are met by formula (a). In this specification, such a structure is also referred to as a "resonant layer."

[0050] In the above formula (a), λ ｐｅａｋ : Emission peak wavelength λ Φ: Phase shift due to reflection (radians) m: Any integer.

[0051] In the following explanation, the position of the reflector 104 is based on the surface from which light is reflected, and the positions of the resonator structure 200 and the light-emitting layer 114 are based on their centers. However, depending on the refractive index difference between the resonator structure 200 and the layers above and below it, the number of antinodes of light waves contained within the resonator structure 200, and the electric field concentration occurring at the ends and surfaces of metals contained within or adjacent to the resonator structure 200, the center of the resonator structure 200 may be offset from the center of its outer shape. In such cases, the emission peak wavelength λ of the light-emitting layer 114 reflected by the reflector 104 is used. ｐｅａｋ Light with the characteristics of and the emission peak wavelength λ resonated in the resonator structure 200 ｐｅａｋ The conditions shown in the above formula (a) are corrected so that the light with the properties interferes and reinforces the other light, and the optical distance L between the resonator structure 200 and the reflector 104 is adjusted. ２ This may also be done. Furthermore, the arrangement of the resonator structure 200 and the reflector 104 may be adjusted depending on the refractive index difference of the materials used, the phase modulation and density due to the nanostructure within the resonator structure 200, etc.

[0052] Because the resonator structure 200 has a very strong interaction with the light-emitting layer 114, it is possible to control much of the light emitted from the light-emitting layer 114 compared to light-ray control techniques such as on-chip lenses 132. Furthermore, because the resonator structure 200 has a very strong interaction with the light-emitting layer 114, it is possible to utilize much of the light of a predetermined wavelength emitted from the light-emitting layer 114 for resonance compared to the microcavity structure described above.

[0053] Furthermore, in the embodiments of the present disclosure devised by the present inventors, a microcavity structure may be applied. In that case, as shown in Figure 5, the optical distance L between the reflector 104 and the upper electrode 118 is １ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ For a given wavelength, the resonance condition shown in equation (1) above will be satisfied.

[0054] In addition, in the embodiments of the present disclosure devised by the present inventors, it is preferable that the light-emitting layer 114 be positioned at a location that becomes an antinode of the light wave in the resonance between the reflector 104 formed by the microcavity structure and the upper electrode 118. Therefore, as shown in Figure 5, the optical distance L between the light-emitting layer 114 and the reflector 104 in the stacking direction of the light-emitting element 100 is ３ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ For (an example of a given wavelength), it is preferable that the conditions shown by the following formula (b) are met.

[0055] In the above formula (b), λ ｐｅａｋ : Emission peak wavelength λ Φ: Phase shift due to reflection (radians) m: Any integer.

[0056] As shown on the left side of Figure 6, in the microcavity structure used in the comparative example, resonance occurs in the vertical direction of the light-emitting element 100. On the other hand, as shown on the right side of Figure 6, in the resonant layer used in this embodiment, resonance occurs in the horizontal direction of the light-emitting element 100. In other words, both structures increase the intensity of light by resonating the light. However, as explained earlier, in the resonant layer, a resonator structure 200 with a high Q value is provided near the light-emitting layer 114, and the resonator structure 200 has a very strong interaction with the light-emitting layer 114. Therefore, in this embodiment, as shown on the right side of Figure 6, the intensity of light with a specific wavelength among the light emitted from the light-emitting layer 114 can be made much higher compared to the comparative example.

[0057] In other words, the light-emitting element 100 according to the embodiment of this disclosure can efficiently obtain light with higher directivity, brightness, and color purity. Accordingly, according to the embodiment of this disclosure, by using such a light-emitting element 100, a display device 10 with a higher frontal radiation intensity of light can be provided. The details of the embodiment of this disclosure created by the present inventors will be described in order below.

[0058] <<3. First Embodiment>> First, an example of the configuration of the light-emitting element 100 according to the first embodiment of the present disclosure will be described with reference to Figure 7. Figure 7 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to the present embodiment.

[0059] The display device 10 according to this embodiment has a top-emission type (upward-emitting type), that is, a plurality of light-emitting elements 100 that emit light upward. In detail, the plurality of light-emitting elements 100 are arranged in a matrix in a predetermined area on the substrate 102 (see Figure 7). Each of the light-emitting elements 100 can be, for example, a light-emitting element 100r that emits red (R) light, a light-emitting element 100g that emits green (G) light, and a light-emitting element 100b that emits blue (B) light.

[0060] In the light-emitting element 100 according to this embodiment, as in the comparative example, as shown in Figure 7, a reflector 104, a spacer layer 106, a lower electrode 110, a transport layer 112, a light-emitting layer 114, a transport layer 116, an upper electrode 118, a spacer layer 120, a color filter 130, and an on-chip lens 132 are sequentially stacked on the substrate 102 in this order. Furthermore, in this embodiment, unlike the comparative example, a resonator structure 200 is provided across the transport layer 112, the light-emitting layer 114, and the transport layer 116. The details of each element constituting the light-emitting element 100 will be described sequentially below.

[0061] (Substrate 102) The substrate 102 can be formed from a transparent material such as glass or a semiconductor material such as silicon. For example, the drive circuit for driving the light-emitting element 100 may be constructed by appropriately forming transistors, wiring, etc., within the various substrates 102 described above.

[0062] (Reflector 104) The reflector 104 can reflect the light emitted from the light-emitting layer 114 upward toward the light-emitting element 100. The reflector 104 can be made of, for example, aluminum (Al), silver (Ag), copper (Cu), or an alloy thereof. In this embodiment, the reflector 104 can be provided below the resonator structure 200, which will be described later.

[0063] (Spacer layer 106) The spacer layer 106 can be formed from, for example, an inorganic insulating material such as silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiOxNy), or from an organic resin material such as an acrylic resin or a polyimide resin. The spacer layer 106 may also be a single layer or a laminate of the above-mentioned material.

[0064] In this embodiment, the intensity of light may be increased by optimizing the distance between the reflector 104 and the upper electrode (reflective surface) 118 (satisfying the resonance condition), thereby causing the light from the light-emitting layer 114 to resonate between the reflector 104 and the upper electrode 118 (microcavity structure). In that case, the above resonance condition can be satisfied by adjusting the film thickness of the spacer layer 106.

[0065] (Lower electrode 110) The lower electrode 110 can be formed from a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO).

[0066] (Transport Layer 112) The transport layer 112 is, for example, a hole transport layer. Specifically, the transport layer 112 can be composed of, for example, α-NPD[N,N'-di(1-naphthyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine]. In this embodiment, a hole injection layer may also be provided between the lower electrode 110 and the transport layer 112. The hole injection layer can be composed of, for example, hexaazatriphenylene (HAT).

[0067] (Emitting layer 114) The emitting layer 114 can be a red emitting layer that emits red light, a green emitting layer that emits green light, a blue emitting layer that emits blue light, or a stack of these (for example, a tandem type white emitting layer).

[0068] The red light-emitting layer generates red light when an electric field is applied, as some of the holes injected from the lower electrode 110 via the hole injection layer and hole transport layer 112 recombine with some of the electrons injected from the upper electrode 118 via the electron transport layer 116. The red light-emitting layer includes, for example, at least one of 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).

[0069] The blue light-emitting layer generates blue light when an electric field is applied, as some of the holes injected from the lower electrode 110 via the hole injection layer and hole transport layer 112 recombine with some of the electrons injected from the upper electrode 118 via the electron transport layer 116. 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).

[0070] The green light-emitting layer generates green light when an electric field is applied, as some of the holes injected from the lower electrode 110 via the hole injection layer and hole transport layer 112 recombine with some of the electrons injected from the upper electrode 118 via the electron transport layer 116. The green light-emitting layer includes, for example, at least one of 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 made of, for example, DPVBi mixed with 5% by weight of coumarin 6.

[0071] In the above description, the light-emitting layer 114 was described as being made of an organic light-emitting material, but in this embodiment, it is not limited to this. In this embodiment, the light-emitting layer 114 can be formed from an inorganic light-emitting material (such as GaN), a perovskite material, a colloidal quantum dot (QD) material, a quantum well material, or a mixture thereof. In this embodiment, the perovskite material is, for example, ABX ３ The composition can be a metal halide perovskite. For example, here A is cesium (Cs) and a methylamino group (CH ３ NH ３ , HC (NH ２ ) ２ ) etc., B can be lead (Pb), tin (Sn), etc., and X can be chlorine (Cl), bromine (Br), iodine (I), etc. Furthermore, the perovskite material may be a quantum dot structure, as described later, in addition to the usual bulk structure.

[0072] Furthermore, colloidal quantum dot materials are nanoscale structures with unique optical properties that follow quantum mechanics, and typically have a diameter of several nanometers. Generally, colloidal quantum dot materials allow for adjustment of the band gap by size, thus enabling particle size-dependent optical confinement. Colloidal quantum dot materials have the characteristic of being able to adjust the wavelength of light to be confined by the particle size, and not only do they have a narrow spectral full width at half maximum, but also high quantum efficiency. In detail, a colloidal quantum dot material has, for example, a core and a shell that covers the surface of the core. The core and shell can be formed from, for example, an inorganic compound material. Examples of inorganic compound materials include CdSe, CdS, CdZnSe, CdTe, ZnSe, ZnS, ZnTe, and InP.

[0073] Furthermore, in this embodiment, the light-emitting layer 114 may be a color conversion layer that is excited by incident light from an adjacent layer and emits light of a predetermined color. In this embodiment, for example, a color conversion layer made of colloidal quantum dot material may be placed on the blue light-emitting layer. Also, in this embodiment, the color conversion layer does not have to be sandwiched between the lower electrode 110 and the upper electrode 118.

[0074] (Transport Layer 116) The transport layer 116 is, for example, an electron transport layer. Specifically, the transport layer 116 can be, for example, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), Alq3 (aluminum quinolinol), Bphen (basophenanthroline), etc. 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.

[0075] An electron transport layer doped with an alkali metal or alkaline earth metal can be constructed by co-depositing, for example, 0.5 to 15% by weight, of an alkali metal such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), or cesium (Cs), or an alkaline earth metal such as magnesium (Mg), calcium (Ca), strontium (Sr), or barium (Ba), as a host material.

[0076] Furthermore, an electron injection layer may be provided between the electron transport layer 116 and the upper electrode 118. 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, or 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.

[0077] Furthermore, a buffer layer may be provided between the electron transport layer 116 and the upper electrode 118. The buffer layer is intended to mitigate process damage to the light-emitting layer 114, etc., during the deposition of the upper electrode 118. The buffer layer may be made of, for example, magnesium (Mg), magnesium-silver alloy (MgAg), calcium (Ca), lithium (Li), lithium fluoride (LiF), 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.

[0078] Furthermore, in this embodiment, the layering is not limited to being stacked in the order of transport layer 112, light-emitting layer 114, and transport layer 116 from bottom to top, but may be stacked in an inverted order.

[0079] (Upper electrode 118) In this embodiment, the upper electrode 118 preferably functions as a semi-transparent reflective film and an electrode. In this case, the upper electrode 118 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. Alternatively, in this embodiment, the upper electrode 118 may be formed from a transparent conductive material that has good light transmittance to visible light (for example, visible light with wavelengths of about 360 nm to 780 nm) and a small work function. For example, the upper electrode 118 can be formed from a metal film containing at least one of the elements and alloys of metals such as aluminum (Al), magnesium (Mg), calcium (Ca), sodium (Na), and silver (Ag). Specific examples of alloys include aluminum (Al) alloys such as MgAg alloy or AlLi alloy, and silver (Ag) alloys. Furthermore, the upper electrode 118 may be formed from a transparent conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), or zinc oxide (ZnO).

[0080] (Spacer layer 120) The spacer layer 120 can be formed from, for example, an inorganic insulating material such as silicon nitride, silicon oxide, or silicon oxynitride, or from an organic resin material such as an acrylic resin or a polyimide resin. The spacer layer 120 may also be a single layer or a laminate of the above-mentioned material. In this embodiment, the spacer layer 120 has the function of positioning the on-chip lens 132 in an appropriate location and protecting the light-emitting layer 114 below it.

[0081] (Color filter 130) The color filter 130 can be formed from a color filter that transmits red wavelength components, a color filter that transmits green wavelength components, or a color filter that transmits blue wavelength components. The color filter 130 can be formed from a material in which a pigment or dye is dispersed in a transparent binder such as silicone. In this embodiment, the color filter 130 may not be provided.

[0082] (On-chip lens 132) The on-chip lens 132 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 132 can emit light as collimated light towards the upper front of the light-emitting element 100 or diagonally upward of the light-emitting element 100, that is, in a desired direction. Furthermore, in this embodiment, the on-chip lens 132 is not limited to being provided on the color filter 130 (or spacer layer 120), but may be provided on, for example, another substrate (not shown) located several μm above the color filter 130.

[0083] In this embodiment, the lens structure is not limited to the on-chip lens 132, but any lens structure capable of guiding light in a desired direction is acceptable. 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, it is not limited to being provided for each light-emitting element 100 (sub-pixel 400), but may be provided so as to span multiple light-emitting elements 100.

[0084] (Resonator Structure 200) In this embodiment, the resonator structure 200 is made of, for example, a photonic crystal structure. A photonic crystal structure is an artificial crystal with a nanoperiodic structure in which materials with different refractive indices are arranged at intervals approximately the same as the wavelength of light, and it can confine and resonate with light of a desired wavelength. Specifically, in the photonic crystal structure, a plurality of holes with nanoscale diameters are periodically provided. These holes may be cavities, or they may be filled with materials that have a different refractive index than the surrounding material. In this specification, such a structure is also referred to as a nanostructure. In this embodiment, since the photonic crystal structure can resonate with light of a specific wavelength, the brightness and color purity of the light can be increased. In other words, in this embodiment, the luminescence efficiency of the light-emitting element 100 can be increased. Furthermore, in this embodiment, by using a photonic crystal structure, light can be confined in the lateral direction and the resonant mode light can be extracted in the film thickness direction of the resonator structure 200, so that the light can be extracted in a highly directional state.

[0085] Furthermore, in this embodiment, the resonator structure 200 is not limited to a photonic crystal structure, but may be a nanometal, nanogap, high refractive index dielectric, etc. Moreover, in this specification, the above-mentioned nanostructures include photonic crystal structures, nanometals, nanogap, high refractive index dielectric, etc.

[0086] For example, the resonator structure 200 may have a high refractive index relative to the upper and lower layers and function as a so-called slab that confines light in the vertical direction. This slab acts complementaryly with the nanostructure described above to confine light, interacts with the material's light emission process, and promotes the emission of resonant mode light, or resonates the waveguide light, thereby realizing the emission of resonant mode light. Specifically, SiN with refractive index n2.0 ｘ By sandwiching a layer made of a material with a refractive index n1.7 between the layers made of SiN ｘ A layer consisting of these elements functions as a slab. In this case, the optical path length within the slab is about twice that of a vacuum. SiN ｘ Even if a low refractive index layer with a thickness of about 20 nm is embedded within the layer, the function of the slab will not be impaired. Therefore, a part of the slab may be processed or made of a different material. Furthermore, the thickness of the slab may be thicker than described above so that multiple antinodes are included in the resonator structure.

[0087] Furthermore, as shown in Figure 7, the resonator structure 200 is provided spanning within the transport layer 112, the light-emitting layer 114, and the transport layer 116. In this embodiment, the resonator structure 200 may be provided only within the light-emitting layer 114, or it may be provided in the light-emitting layer 114 and one of the two transport layers 112 and 116.

[0088] Furthermore, in this embodiment, of the light resonated in the resonator structure 200, the light that propagates downward from the resonator structure 200 is reflected by the reflector 104 located below the resonator structure 200, thereby allowing a large amount of light to propagate upward from the light-emitting element 100 and reach the on-chip lens 132.

[0089] Furthermore, in this embodiment, the distance between the resonator structure 200 and the reflector 104 is optimized so that, in the resonator structure 200, the light of a predetermined wavelength reflected by the reflector 104 and the light of a predetermined wavelength resonated in the resonator structure 200 interfere with each other and reinforce each other.

[0090] In detail, in this embodiment, the optical distance L between the resonator structure 200 and the reflector 104 in the stacking direction of the light-emitting element 100 is ２ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ The following condition is satisfied:

[0091] In the above formula (a), λ ｐｅａｋ : Emission peak wavelength Φ: Phase shift due to reflection (radians) m: Any integer.

[0092] In this embodiment, by doing so, in the resonator structure 200, the light with a predetermined wavelength reflected by the reflector 104 and the light with a predetermined wavelength resonated in the resonator structure 200 can interfere and reinforce each other. Therefore, according to this embodiment, light with higher brightness and color purity can be efficiently obtained.

[0093] Furthermore, in this embodiment, in order to resonate light between the reflector 104 and the upper electrode 118 using the microcavity structure described above, the optical distance L between the reflector 104 and the upper electrode 118 is set. １ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ It is preferable to satisfy the resonance conditions shown in the following formula (1). In this case, the upper electrode 118 functions as a semi-transparent reflective film and an electrode.

[0094] In the above formula (1), λ ｐｅａｋ : Emission peak wavelength λ Φ: Phase shift due to reflection (radians) m: Any integer.

[0095] Furthermore, in this embodiment, it is preferable that the light-emitting layer 114 be positioned at the antinode of the light wave in the optical resonance between the reflector 104 formed by the microcavity structure and the upper electrode 118. Therefore, in the stacking direction of the light-emitting element 100, the optical distance L between the light-emitting layer 114 and the reflector 104 is... ３ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ It is preferable to satisfy the conditions shown by the following formula (b).

[0096] In the above formula (b), λ ｐｅａｋ : Emission peak wavelength Φ: Phase shift due to reflection (radians) m: Any integer.

[0097] In this embodiment, since the resonator structure 200 is provided within the light-emitting layer 114, the optical distance L between the resonator structure 200 and the reflector 104 is ２ The optical distance L between the light-emitting layer 114 and the reflector 104. ３ This is equal to the optical distance L between the resonator structure 200 and the reflector 104. ２ If the conditions shown in equation (a) above are met, then the optical distance L between the light-emitting layer 114 and the reflector 104 is ３ This satisfies the above formula (b).

[0098] As described above, in this embodiment, in the resonator structure 200, light with a predetermined wavelength reflected by the reflector 104 and light with a predetermined wavelength resonated in the resonator structure 200 can interfere and reinforce each other. Therefore, according to this embodiment, light with higher brightness and color purity can be efficiently obtained. As a result, according to this embodiment, a display device 10 with a higher frontal radiation intensity of light can be provided.

[0099] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 7, but can take on various forms.

[0100] <<4. Second Embodiment>> Next, an example of the configuration of the light-emitting element 100 according to the second embodiment of the present disclosure will be described with reference to Figure 8. Figure 8 is a schematic diagram showing an example of the cross-sectional configuration of the light-emitting element 100 according to the present embodiment.

[0101] In this embodiment, the resonator structure 200 is provided within the lower electrode 110, and the distance between the resonator structure 200 and the reflector 104 is optimized so that the light of a predetermined wavelength reflected by the reflector 104 and the light of a predetermined wavelength resonated in the resonator structure 200 interfere with and reinforce each other. According to this embodiment, since the resonator structure 200 is provided within the lower electrode 110, the manufacturing of the light-emitting element 100 becomes easier than when the resonator structure 200 is provided within the transport layer 112, the light-emitting layer 114, and the transport layer 116, as in the first embodiment described above.

[0102] In this embodiment, the resonator structure 200 is not particularly limited as long as it is provided in a layer located near the light-emitting layer 114, but the distance between each light-emitting element 100 and the light-emitting layer 114 in the stacking direction is such that the distance is equal to the emission peak wavelength λ of the light-emitting layer 114. ｐｅａｋ It is preferable that the layer is located within a range of the length of the layer.

[0103] More specifically, in this embodiment, the optical distance L between the resonator structure 200 and the reflector 104 in the stacking direction of the light-emitting element 100 is ２ The emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ The following condition is satisfied:

[0104] In the above formula (a), λ ｐｅａｋ : Emission peak wavelength Φ: Phase shift due to reflection (radians) m: Any integer.

[0105] In this embodiment, the distance L between the resonator structure 200 and the reflector 104 is ２ As the above formula (a) is satisfied, in the resonator structure 200, the light with a predetermined wavelength reflected by the reflector 104 and the light with a predetermined wavelength resonated in the resonator structure 200 can interfere and reinforce each other. Therefore, according to this embodiment, light with higher brightness and color purity can be efficiently obtained.

[0106] As described above, in this embodiment, in the resonator structure 200, light with a predetermined wavelength reflected by the reflector 104 and light with a predetermined wavelength resonated in the resonator structure 200 can interfere and reinforce each other. Therefore, according to this embodiment, light with higher brightness and color purity can be efficiently obtained. As a result, according to this embodiment, a display device 10 with a higher frontal radiation intensity of light can be provided.

[0107] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 8, but can take on various forms.

[0108] <<5. Third Embodiment>> Next, with reference to Figure 9, an example of the configuration of the light-emitting element 100 according to the third 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 the present embodiment.

[0109] In this embodiment, as shown in Figure 9, the photonic crystal structure 200a used as the resonator structure is provided within the lower electrode 110, similar to the second embodiment described above. However, unlike the comparative example, in this embodiment, as shown in Figure 9, the photonic crystal structure 200a is non-uniform in plane, and areas where the periodic arrangement of pores is disrupted (partial defects in the periodic structure), i.e., minute defects 260 where no pores exist, are introduced. It is preferable that the defects 260 are spaces with small mode volumes. Specifically, for example, the emission peak wavelength λ of the light-emitting layer 114 ｐｅａｋ If the value is 500 nm, the area of ​​defect 260 is 10 μm. ３It is preferable to have a region of less than a certain magnitude. In this embodiment, light having a predetermined wavelength corresponding to the periodic structure of the photonic crystal structure 200a is confined and resonates at the location of the minute defect 260. That is, the defect 260 functions as the main resonant part of the photonic crystal structure 200a, where the resonant mode light is dominant. Therefore, in this embodiment, since the photonic crystal structure 200a can resonate with light of a specific wavelength, the brightness and color purity of the light can be increased. In other words, in this embodiment, the luminescence efficiency of the light-emitting element 100 can be further increased. In the following description, the region of the defect 260 will also be referred to as the light confinement region A.

[0110] Furthermore, in this embodiment, it is preferable to increase the Q value of the photonic crystal structure 200a. In addition, the photonic crystal structure 200a in this embodiment can resonate light within a very small mode volume (V). Specifically, since the lattice density in the optical resonator of the photonic crystal structure 200a is proportional to Q / V, by making the resonator volume V small and increasing the Q value, light can be confined in a small region at an extremely high density for a long time. Therefore, the speed and intensity of light can be increased by the Purcell effect. Accordingly, in this embodiment, by including such a resonator structure, the direction of light propagation can be controlled and the brightness and color purity of the light can be increased. Also, if the spectral linewidth of the resonant mode determined by the Q value is lower than the spectral linewidth of the material of the light-emitting layer 114 (typically 20 to 50 nm), the Purcell effect may saturate, but even in such cases, the effect of increasing color purity is increased. On the other hand, in such cases, self-absorption and speckle noise of the material tend to become more apparent. Therefore, in regions where the spectral linewidth of the resonant mode is lower than the spectral linewidth of the material, it is preferable to design with attention to the balance of each parameter.

[0111] Note that in this embodiment, the photonic crystal structure 200a is not limited to a photonic crystal structure having the above-described defect. In this embodiment, for example, by changing the size, interval, and shape of some unit structures in the photonic crystal structure, a photonic crystal structure including a disturbance in the periodic structure may be used. Alternatively, in this embodiment, the microstructures may be a photonic crystal structure including a plurality of disturbances in the periodic structure. Further, in this embodiment, the photonic crystal structure may include a waveguide that guides and confines light to a predetermined microregion.

[0112] Also, in this embodiment, instead of such a photonic crystal structure 200a, a micro metal / dielectric having a size equal to or less than the wavelength of light, or a micro nano-gap formed by a metal / dielectric may be used. The nano-gap has a waveguide structure, and can guide the light from the light-emitting layer 114 to a microregion and cause resonance.

[0113] Further, in this embodiment, two reflectors 104a and 104b are provided. The reflector (first reflector) 104a is located below the defect 260 which is the light confinement region A. The reflector 104a is arranged such that light having the emission peak wavelength λ ｐｅａｋ of the light-emitting layer 114 reflected by the reflector 104a and light having the emission peak wavelength λ ｐｅａｋ resonated by the defect 260 which is the light confinement region A interfere with each other and enhance each other.

[0114] Specifically, in this embodiment, in the stacking direction of the light-emitting device 100, the optical distance L ４ between the photonic crystal structure 200a (specifically, the light confinement region A of the photonic crystal structure 200a) and the reflector 104a satisfies the condition represented by the following mathematical formula (c) with respect to the emission peak wavelength λ ｐｅａｋ of the light-emitting layer 114.

[0115] In the above mathematical formula (c), λ ｐｅａｋ: Emission peak wavelength, Φ: Phase shift due to reflection (radians), m: Any integer.

[0116] In the present embodiment, the distance L between the photonic crystal structure 200a (specifically, the light confinement region A of the photonic crystal structure 200a) and the reflector 104a ４ By satisfying the above formula (c), light having a predetermined wavelength reflected by the reflector 104a and light having a predetermined wavelength resonated by the photonic crystal structure 200a can interfere with each other and reinforce each other. Therefore, according to the present embodiment, light having higher luminance and color purity can be efficiently obtained.

[0117] Further, in the present embodiment, as shown in FIG. 9, the reflector (second reflector) 104b is located below a region other than the defect 260 which is the light confinement region A. And in the present embodiment, in order to resonate light between the reflector (second reflector) 104b and the upper electrode 118 by the above-described microcavity structure, the optical distance L between the reflector 104b and the upper electrode 118 ６ is preferably such that it satisfies the resonance condition represented by the following formula (2) with respect to the emission peak wavelength λ of the light emitting layer 114 ｐｅａｋ

[0118] In the above formula (2), λ ｐｅａｋ : Emission peak wavelength λ, Φ: Phase shift due to reflection (radians), m: Any integer.

[0119] Further, in the present embodiment, the light emitting layer 114 is preferably provided at the position of the antinode of the light wave in the resonance of light between the reflector 104b and the upper electrode 118 in the above-described microcavity structure. Therefore, in the present embodiment, in the stacking direction of the light emitting element 100, the optical distance L between the light emitting layer 114 and the reflector 104b ５ is preferably such that it satisfies the condition represented by the following formula (d) with respect to the emission peak wavelength λ of the light emitting layer 114 ｐｅａｋ

[0120] In the above formula (d), λ ｐｅａｋ: The predetermined wavelength Φ: Phase shift due to reflection (in radians) m: Any integer.

[0121] Thus, in this embodiment, as shown in Figure 9, the optical distance L between the optical confinement region A, which is the main resonant region of the photonic crystal structure 200a, and the reflector 104a is as follows: ４ This is done to satisfy the above formula (c). Furthermore, in this embodiment, in regions other than the photoconfinement region A of the photonic crystal structure 200a, a microcavity structure is formed, and the optical distance L between the reflector 104b and the upper electrode 118 is set. ６ The optical distance L between the light-emitting layer 114 and the reflector 104b is set to satisfy the above formula (2). ５ It is preferable to satisfy the above formula (d). In this embodiment, these formulas can be satisfied by providing two reflectors 104a and 104b.

[0122] Therefore, in this embodiment, as shown in Figure 9, the distance between the photon confinement region A, which is the main resonant part of the photon crystal structure 200a, and the reflector 104a is different from the distance between the region of the photon crystal structure 200a other than the photon confinement region A and the reflector 104b.

[0123] As described above, in this embodiment, in the light confinement region A of the photonic crystal structure 200a, light with a predetermined wavelength reflected by the reflector 104a and light with a predetermined wavelength resonating in the photonic crystal structure 200a can interfere and reinforce each other. Therefore, according to this embodiment, light with higher brightness and color purity can be efficiently obtained. As a result, according to this embodiment, a display device 10 with a higher frontal radiation intensity of light can be provided.

[0124] In this embodiment, the light-emitting element 100 is not limited to the form shown in Figure 9, but can take on various forms.

[0125] <<6. Summary>> As described above, in each embodiment of this disclosure, the resonator structure 200 allows light of a predetermined wavelength reflected by the reflector 104 and light of a predetermined wavelength resonated in the resonator structure 200 to interfere and reinforce each other. Therefore, according to this embodiment, light with higher brightness and color purity can be efficiently obtained. As a result, according to this embodiment, a display device 10 with a higher frontal radiation intensity of light can be provided.

[0126] In each embodiment of this disclosure, the peak wavelength of the intrinsic resonant component of the resonator structure 200 is the emission peak wavelength λ of the light-emitting layer 114. ｐｅａｋ Alternatively, the emission peak wavelength λ may be shifted up to approximately half-width of the emission peak. For example, the emission peak wavelength λ of the emission layer 114 ｐｅａｋ When the wavelength is approximately 530 nm, the peak wavelength wp of the intrinsic resonance component of the resonator structure 200 is set to 535 nm. By doing so, the distance between the resonator structure 200 and the reflector 104 can be made longer than the distance between the light-emitting layer 114 and the reflector 104. In this way, the resonator structure 200 can be moved further away from the reflector 104 than the light-emitting layer 114. When using light-emitting materials such as organic light-emitting materials, where the emission wavelength and absorption wavelength are close, that is, light-emitting materials that self-absorb light, this method can be used to prevent much of the light resonated in the resonator structure 200 from being absorbed by the light-emitting layer 114.

[0127] Furthermore, in each embodiment of the present disclosure described above, the light-emitting element 100 may include a light-emitting element 100 that emits red (R) light, a light-emitting element 100 that emits green (G) light, a light-emitting element 100 that emits blue (B) light, and so on. In such cases, the refractive index difference of the layers sandwiching the resonator structure 200 from above and below may be changed for each color of light emitted by the light-emitting element 100. Also in such cases, the film thickness of the spacer layers 106 and 120 may be changed for each color of light emitted by the light-emitting element 100. Furthermore, in such cases, the period of the resonator structure 200 may be changed for each color of light emitted by the light-emitting element 100. In addition, in such cases, a fine structure may be introduced on the surface of the reflector 104, and the amount of phase shift by reflection may be changed for each color of light emitted by the light-emitting element 100.

[0128] Furthermore, in each embodiment of the present disclosure described above, the light-emitting layer 114 of the light-emitting element 100 may be, for example, a stack of a red light-emitting layer that generates red light, a green light-emitting layer that generates green light, and a blue light-emitting layer that generates blue light (for example, a tandem-type white light-emitting layer). In such cases, a plurality of resonator structures 200 and a plurality of reflectors 104 having configurations corresponding to each wavelength of light may be provided. For example, a reflector 104 that reflects light of a specific wavelength may be constructed using a dielectric multilayer film or a micromirror structure, and each reflector 104 may be placed at a position having an optical path length corresponding to the wavelength of the corresponding light. Alternatively, for example, a plurality of resonator structures 200 forming a tandem structure may be placed at a position having an optical path length corresponding to the wavelength of the corresponding light with respect to one reflector 104. In this case, by adjusting the thickness of the resonator structures 200, it is not necessary to arrange the resonator structure 200 corresponding to long wavelength light so that it is furthest from the reflector 104. Furthermore, the position of the light confinement region A may be changed for each resonator structure 200 corresponding to each wavelength of light. For example, in the resonator structure 200 corresponding to red light, a defect 260 may be introduced slightly to the left of the center of the light-emitting element 100 so that red light is emitted slightly to the left of the center of the light-emitting element 100. Furthermore, in the resonator structure 200 corresponding to blue light, a defect 260 may be introduced slightly to the right of the center of the light-emitting element 100 so that blue light is emitted slightly to the right of the center of the light-emitting element 100. In this case, it is preferable to provide a reflector 104 below the emission position of each color of light with an optical path length corresponding to the wavelength of each color. Alternatively, it is preferable to adjust each resonator structure 200 relative to the reflector 104 so that the optical path length corresponds to the wavelength of each color.

[0129] Furthermore, in each embodiment of the present disclosure described above, for example, if a plurality of resonator structures 200 are provided, the polarization component resonated by each resonator structure 200 may be changed. Specifically, for example, a resonator structure 200 that resonates with red light and a resonator structure 200 that resonates with blue light resonate with mutually orthogonal polarization components. In such a case, the optical path length and phase can be adjusted by utilizing the polarization characteristics of the reflector 104 or the intermediate medium layer.

[0130] 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.

[0131] 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.

[0132] Examples of the methods mentioned above include the PVD (Physical Vapor Deposition) method, the CVD (Chemical Vapor Deposition) method, and the ALD (Atomic Layer Deposition) method. Examples of PVD methods include vacuum deposition, electron beam (EB) deposition, various sputtering methods (magnetron sputtering, RF (Radio Frequency)-DC (Direct Current) coupled bias sputtering, ECR (Electron Cyclotron Resonance) sputtering, counter-target sputtering, high-frequency sputtering, etc.), ion plating, laser ablation, molecular beam epitaxy (MBE (Molecular Beam Epitaxy)), and laser transfer. Examples of CVD methods include plasma CVD, thermal CVD, metal-organic (MO) CVD, and optical CVD. Furthermore, other methods include electrolytic plating, electroless plating, spin coating, immersion, casting, microcontact printing, drop casting, various printing methods such as screen printing, inkjet printing, offset printing, gravure printing, and flexographic printing, as well as stamping, spraying, air doctor coater, blade coater, rod coater, knife coater, squeeze coater, reverse roll coater, transfer roll coater, gravure coater, kiss coater, cast coater, spray coater, slit orifice coater, and calender coater. In addition, patterning methods include chemical etching such as shadow masks, laser transfer, and photolithography, as well as physical etching using ultraviolet light or lasers. Furthermore, planarization techniques include CMP (Chemical Mechanical Polishing), laser planarization, and reflow.

[0133] <<7. Modifications>> <7.1 Modification 1> Next, as a modification of the embodiment of the present disclosure, a modification of 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 132 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 130 provided on the light-emitting element 100) will be described with reference to Figures 10A to 10G. Figures 10A to 10G 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. In the following description, the "center of the light-emitting unit" corresponds to the center of the light-confinement region A, which is the region of the defect 260, when applied to the third embodiment of the present disclosure described above.

[0134] 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.

[0135] For example, as shown in Figure 10A, 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).

[0136] Furthermore, for example, as shown in Figure 10B, 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.

[0137] Furthermore, for example, as shown in Figure 10C, 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.

[0138] Furthermore, as shown in Figure 10D, 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 10D) 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 10D). 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.

[0139] 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 10E, 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.

[0140] Furthermore, for example, as shown in Figure 10F, 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.

[0141] Furthermore, as shown in the conceptual diagram Figure 10G, 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 10G) 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 10G) 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.

[0142] <7.2 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 114. However, the resonator structure (microcavity structure) in this Modification 2 refers to a structure that confines the light-emitting element 100 in one dimension in the stacking direction (vertical direction). The above resonator structure will be described below with reference to Figures 11 to 17. Figure 11 is a schematic cross-sectional view illustrating a first example of the resonator structure, Figure 12 is a schematic cross-sectional view illustrating a second example of the resonator structure, and Figure 13 is a schematic cross-sectional view illustrating a third example of the resonator structure. Furthermore, Figure 14 is a schematic cross-sectional view illustrating a fourth example of the resonator structure, and Figure 15 is a schematic cross-sectional view illustrating a fifth example of the resonator structure. Furthermore, Figure 16 is a schematic cross-sectional view illustrating a sixth example of the resonator structure, and Figure 17 is a schematic cross-sectional view illustrating a seventh example of the resonator structure. In these figures, the letters attached to each reference numeral indicate the corresponding color; specifically, "B" indicates blue, "G" indicates green, and "R" indicates red.

[0143] (Resonator Structure: First Example) Figure 11 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 110) 1202 is formed with a common film thickness in each subpixel 1100. The same applies to the second electrode (specifically, the upper electrode 118) 1206.

[0144] As shown in Figure 11, a reflector (specifically, a reflector 104) 1401 is positioned below the first electrode 1202 of the subpixel 1100, with an optical adjustment layer (specifically, a spacer layer 106) 1402 in between. A resonator structure is formed between the reflector 1401 and the second electrode 1206, which resonates the light generated by the organic layer (specifically, a light-emitting layer 114) 1204.

[0145] 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.

[0146] In the example shown in Figure 11, 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.

[0147] 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.

[0148] The optical adjustment layer 1402 can be constructed using inorganic insulating materials such as silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiOxNy), or organic resin materials such as acrylic resin or polyimide resin. The optical adjustment layer 1402 may be a single layer or a laminated film of multiple materials. Furthermore, the number of layers may vary depending on the type of subpixel 1100.

[0149] 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).

[0150] 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.

[0151] (Resonator structure: Second example) Figure 12 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.

[0152] 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.

[0153] In the first example shown in Figure 11, 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.

[0154] In contrast, in the second example shown in Figure 12, 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.

[0155] 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.

[0156] (Resonator structure: Third example) Figure 13 is a schematic cross-sectional view illustrating a third example of the resonator structure. In this third example as well, the first electrode 1202 and the second electrode 1206 are formed with a common film thickness in each subpixel 1100.

[0157] 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.

[0158] In the second example shown in Figure 12, 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.

[0159] In contrast, in the third example shown in Figure 13, 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.

[0160] 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.

[0161] (Resonator structure: 4th example) Figure 14 is a schematic cross-sectional view illustrating the 4th example of a resonator structure.

[0162] In the first example shown in Figure 11, 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.

[0163] In contrast, in the fourth example shown in Figure 14, 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.

[0164] 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.

[0165] 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.

[0166] (Resonator structure: Fifth example) Figure 15 is a schematic cross-sectional view illustrating the fifth example of a resonator structure.

[0167] In the first example shown in Figure 11, 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.

[0168] In contrast, in the fifth example shown in Figure 15, 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.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] 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.

[0174] 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.

[0175] (Resonator Structure: Sixth Example) Figure 16 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.

[0176] 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.

[0177] 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.

[0178] (Resonator Structure: Seventh Example) Figure 17 is a schematic cross-sectional view illustrating the seventh example of the resonator structure. The seventh example basically applies the sixth example to sub-pixels 1100R and 1100G, and the first example to sub-pixel 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.

[0179] 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.

[0180] 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.

[0181] <<8. 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.

[0182] (Specific Example 1) Figure 18A is a front view showing an example of the external appearance of the digital still camera 500, and Figure 18B 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.

[0183] 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.

[0184] (Specific Example 2) Figure 19 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.

[0185] (Specific Example 3) Figure 20 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.

[0186] 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.

[0187] 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.

[0188] 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.

[0189] (Specific Example 4) Figure 21 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.

[0190] (Specific Example 5) Figure 22 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.

[0191] (Specific Example 6) Figures 23A and 23B show the internal configuration of an automobile having a display device 10 according to the embodiment of this disclosure as a display device. More specifically, Figure 23A shows the interior of the automobile from the rear to the front, and Figure 23B shows the interior of the automobile from the diagonally rear to the diagonally front.

[0192] The automobile shown in Figures 23A and 23B 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.

[0193] The center display 911 is positioned on the center console 907, facing the driver's seat 901 and the passenger seat 902. Figures 23A and 23B 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.

[0194] 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.

[0195] 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.

[0196] 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.

[0197] 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.

[0198] 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.

[0199] 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).

[0200] <<9. Supplementary Information>> Although preferred embodiments of the present disclosure have been described in detail above with reference to the attached drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person with ordinary skill in the art of the present disclosure may conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and these will naturally also be understood to fall within the technical scope of the present disclosure.

[0201] 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.

[0202] Furthermore, this technology can also take the following configuration: (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 resonator structure provided in or near the emitting layer and resonating with light of a predetermined wavelength from the light-emitting layer; and a reflector provided below the resonator structure, wherein the reflector and the resonator structure are arranged such that, in the resonator structure, the light of the predetermined wavelength reflected by the reflector and the light of the predetermined wavelength resonated in the resonator structure interfere with and reinforce each other. (2) In the stacking direction of each light-emitting element, the optical distance L between the resonator structure and the reflector. ２ The display device described in (1) above, which satisfies the following formula (a). In the above formula (a), λ ｐｅａｋ: The predetermined wavelength Φ: Phase shift due to reflection (radians) m: Any integer. (3) The display device according to (1) or (2) above, wherein the resonator structure is made of a nanometal, a nanogap, a high refractive index dielectric, or a photonic crystal structure. (4) The display device according to any one of (1) to (3) above, wherein the light-emitting layer is sandwiched between a lower electrode and an upper electrode. (5) The display device according to (4) above, wherein the light-emitting layer is sandwiched between a pair of transport layers in contact with the light-emitting layer. (6) The display device according to (5) above, wherein the resonator structure is provided within the light-emitting layer. (7) The display device according to (6) above, wherein the resonator structure is also provided within at least one of the pair of transport layers. (8) The upper electrode is made of a semi-transparent reflective film, and the optical distance L between the reflector and the upper electrode in the stacking direction of each light-emitting element is １ The display device described in (6) or (7) above, which satisfies the following formula (1). In the above formula (1), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (radians) m: Any integer. (9) The optical distance L between the light-emitting layer and the reflector in the stacking direction of each light-emitting element. ３ The display device described in (8) above, which satisfies the following formula (b). In the above formula (b), λ ｐｅａｋ: The predetermined wavelength Φ: Phase shift due to reflection (radians) m: Any integer. (10) The display device according to any one of (1) to (5) above, wherein in the stacking direction of each light-emitting element, the distance between the resonator structure and the light-emitting layer is less than or equal to the predetermined wavelength. (11) The display device according to (4) above, wherein the resonator structure is provided in the lower electrode. (12) The display device according to (4) above, wherein the resonator structure has a nanostructure with a non-uniform in-plane surface. (13) The display device according to (12) above, wherein the resonator structure consists of a minute metal / dielectric having a size less than or equal to the wavelength of light, a minute nanogap formed by the metal / dielectric, or a photonic crystal structure having partial defects in a periodic structure. (14) The display device according to (12) or (13) above, wherein the resonator structure has a light-confining region. (15) The display device according to (14), wherein the reflector includes a first reflector and a second reflector, and the light confinement region and the first reflector located below the light confinement region are arranged such that, in the light confinement region, the light having the predetermined wavelength reflected by the first reflector and the light having the predetermined wavelength resonated in the resonator structure interfere with and reinforce each other. (16) The optical distance L between the light confinement region of the resonator structure and the first reflector in the stacking direction of each light-emitting element. ４ The display device described in (15) above, which satisfies the following formula (c). In the above formula (c), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (radians) m: Any integer. (17) The display device according to (15) or (16) above, wherein the second reflector is located below the region other than the light confinement region, and the distance between the light confinement region and the first reflector is different from the distance between the region of the resonator structure other than the light confinement region and the second reflector. (18) The upper electrode is made of a semi-transparent reflective film, and the optical distance L between the second reflector and the upper electrode in the stacking direction of each light-emitting element ６ The display device described in (17) above, which satisfies the following formula (2). In the above formula (2), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (radians) m: Any integer. (19) Optical distance L between the second reflector and the light-emitting layer ５ The display device described in (18) above, which satisfies the following formula (d). In the above formula (d), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (radians) m: Any integer. (20) The display device according to any one of (1) to (19) above, wherein the light-emitting layer is made of an inorganic light-emitting material, an organic light-emitting material, a perovskite material, a colloidal quantum dot material, or a mixture thereof.

[0203] 10 Display device 11 Horizontal drive circuit 12 Vertical drive circuit 20 Pixel array section 40 Display panel 100, 100a, 100b, 100g, 100r Light-emitting element 102 Substrate 104, 104a, 104b Reflector 106, 120 Spacer layer 110, 118 Electrode 112, 116 Transport layer 114 Light-emitting layer 130 Color filter 132 On-chip lens 200 Cavity structure 200a Photonic crystal structure 260 Defect 400, 400B, 400G, 400R Subpixel

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 resonator structure provided within or near the light-emitting layer and resonating with light of a predetermined wavelength from the light-emitting layer; and a reflector provided below the resonator structure, wherein the reflector and the resonator structure are arranged such that, in the resonator structure, the light of the predetermined wavelength reflected by the reflector and the light of the predetermined wavelength resonated in the resonator structure interfere with and reinforce each other.

2. In the stacking direction of each of the light-emitting elements, the optical distance L between the resonator structure and the reflector ２ The display device according to claim 1, wherein the following formula (a) is satisfied. In the above formula (a), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (in radians) m: Any integer.

3. The display device according to claim 1, wherein the resonator structure is made of a nanometal, a nanogap, a high refractive index dielectric, or a photonic crystal structure.

4. The display device according to claim 1, wherein the light-emitting layer is sandwiched between a lower electrode and an upper electrode.

5. The display device according to claim 4, wherein the light-emitting layer is sandwiched between a pair of transport layers in contact with the light-emitting layer.

6. The display device according to claim 5, wherein the resonator structure is provided within the light-emitting layer.

7. The display device according to claim 6, wherein the resonator structure is also provided within at least one of the pair of transport layers.

8. The upper electrode is made of a semi-transparent reflective film, and the optical distance L between the reflector and the upper electrode is in the stacking direction of each light-emitting element. １ The display device according to claim 6, wherein the following formula (1) is satisfied. In the above formula (1), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (in radians) m: Any integer.

9. In the stacking direction of each of the light-emitting elements, the optical distance L between the light-emitting layer and the reflector. ３ The display device according to claim 8, wherein the following formula (b) is satisfied. In the above formula (b), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (in radians) m: Any integer.

10. The display device according to claim 1, wherein, in the stacking direction of each light-emitting element, the distance between the resonator structure and the light-emitting layer is less than or equal to the predetermined wavelength.

11. The display device according to claim 4, wherein the resonator structure is provided within the lower electrode.

12. The display device according to claim 4, wherein the resonator structure has a non-uniform nanostructure in its plane.

13. The display device according to claim 12, wherein the resonator structure comprises a minute metal or dielectric having a size smaller than the wavelength of light, a minute nanogap formed by the metal or dielectric, or a photonic crystal structure having partial defects in a periodic structure.

14. The display device according to claim 12, wherein the resonator structure has a light confinement region.

15. The display device according to claim 14, wherein the reflector includes a first reflector and a second reflector, and the light confinement region and the first reflector located below the light confinement region are arranged such that, in the light confinement region, the light having the predetermined wavelength reflected by the first reflector and the light having the predetermined wavelength resonated in the resonator structure interfere with and reinforce each other.

16. In the stacking direction of each of the light-emitting elements, the optical distance L between the optical confinement region of the resonator structure and the first reflector. ４ The display device according to claim 15, wherein the following formula (c) is satisfied. In the above formula (c), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (in radians) m: Any integer.

17. The display device according to claim 15, wherein the second reflector is located below the region other than the light confinement region, and the distance between the light confinement region and the first reflector is different from the distance between the region of the resonator structure other than the light confinement region and the second reflector.

18. The upper electrode is formed of a semi-transmissive reflective film, and in the stacking direction of the light-emitting elements, the optical distance L between the second reflector and the upper electrode ６ satisfies the following mathematical formula (2), and the display device according to claim 17. In the above mathematical formula (2), λ ｐｅａｋ : the predetermined wavelength, Φ: phase shift due to reflection (radian), m: an arbitrary integer.

19. The optical distance L between the second reflector and the light-emitting layer. ５ The display device according to claim 18, which satisfies the following formula (d). In the above formula (d), λ ｐｅａｋ : The predetermined wavelength Φ: Phase shift due to reflection (in radians) m: Any integer.

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

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