Light-emitting element, light-emitting device, display device, and method for driving light-emitting element

Abstract

A blue light-emitting element (20B) provided to a display device (1) comprises a semi-reflective first electrode (12a) and a semi-reflective second electrode (12b) having a greater thickness than the semi-reflective first electrode (12a), a reflective third electrode (3B), and a blue light-emitting layer (8B) provided between the reflective third electrode (3B) and each of the semi-reflective first electrode (12a) and the semi-reflective second electrode (12b). The semi-reflective first electrode (12a) overlaps a portion of the blue light-emitting layer (8B) and a portion of the reflective third electrode (3B) in plan view, and the semi-reflective second electrode (12b) overlaps another portion of the blue light-emitting layer (8B) and another portion of the reflective third electrode (3B) in plan view.

Description

Light-emitting element, light-emitting device, display device, and method for driving light-emitting element

[0001] The present disclosure relates to a light-emitting element, a light-emitting device, a display device, and a method for driving a light-emitting element.

[0002] In recent years, display devices equipped with light-emitting elements such as OLEDs (Organic Light Emitting Diodes) or QLEDs (Quantum dot Light Emitting Diodes) have attracted much attention because of their ability to achieve low power consumption, thinness, high image quality, and the like.

[0003] In the field of these display devices, active attempts are being made to achieve even higher image quality. For example, Patent Document 1 describes a display device that includes a first light-emitting element for realizing a priority mode with wide viewing angle characteristics and a second light-emitting element for realizing a priority mode with front luminance (light extraction efficiency).

[0004] International Publication WO2011 / 145174 A1

[0005] In the display device described in Patent Document 1, each pixel is provided with a first light-emitting element for realizing a priority mode for wide viewing angle characteristics and a second light-emitting element for realizing a priority mode for front luminance (light extraction efficiency). The first light-emitting element uses an anode as a lower electrode, which is formed by stacking a 500 nm-thick Ag film and a 10 nm-thick IZO (indium zinc oxide) film in this order from the bottom, while the second light-emitting element uses an anode as a lower electrode, which is formed by stacking a 500 nm-thick Ag film and a 125 nm-thick IZO film in this order from the bottom. This configuration adjusts the distance between the reflective surface of the anode, which is a reflective electrode, and the light-emitting layer, i.e., the distance between the upper surface of the Ag film and the light-emitting layer, thereby providing an optical interference effect only in the second light-emitting element.

[0006] However, in the configuration that provides the above-mentioned optical interference effect that the display device described in Patent Document 1 has, there is a problem that the influence of reflected light that occurs on the upper surface of the IZO film that forms part of the anode, which is a reflective electrode provided in the first light-emitting element, and on the upper surface of the IZO film that forms part of the anode, which is a reflective electrode provided in the second light-emitting element, is large, and satisfactory viewing angle characteristics cannot be obtained in the first light-emitting element and the second light-emitting element.

[0007] An object of one embodiment of the present disclosure is to provide a light-emitting element, a light-emitting device, a display device, and a method for driving a light-emitting element, which can realize improved wide-viewing-angle mode and narrow-viewing-angle mode.

[0008] In order to solve the above-mentioned problems, the light-emitting element of the present disclosure includes a semi-reflective first electrode and a semi-reflective second electrode that is thicker than the semi-reflective first electrode; a reflective third electrode that is located in a layer separate from the semi-reflective first electrode and the semi-reflective second electrode; and a first light-emitting layer that is provided between the semi-reflective first electrode and the semi-reflective second electrode and the reflective third electrode, respectively, wherein the semi-reflective first electrode overlaps with a portion of the first light-emitting layer and a portion of the reflective third electrode in a planar view, and the semi-reflective second electrode overlaps with another portion of the first light-emitting layer and another portion of the reflective third electrode in a planar view.

[0009] In order to solve the above-mentioned problems, the present disclosure provides a driving method for a light-emitting element comprising: a semi-reflective first electrode; a semi-reflective second electrode that is thicker than the semi-reflective first electrode; a reflective third electrode that is located in a layer separate from the semi-reflective first electrode and the semi-reflective second electrode; and a first light-emitting layer that is provided between each of the semi-reflective first electrode and the semi-reflective second electrode and the reflective third electrode, and the method includes a wide viewing angle mode in which only a first region where the semi-reflective first electrode, a portion of the first light-emitting layer, and a portion of the reflective third electrode overlap in a planar view, emits light; and a narrow viewing angle mode in which only a second region where the semi-reflective second electrode, another portion of the first light-emitting layer, and another portion of the reflective third electrode overlap in a planar view, emits light.

[0010] According to one aspect of the present disclosure, it is possible to provide a light-emitting element, a light-emitting device, a display device, and a method for driving a light-emitting element, which are capable of realizing an improved wide viewing angle mode and narrow viewing angle mode.

[0011] 1 is a cross-sectional view showing a schematic configuration of a display device of Embodiment 1. FIG. 2 is a plan view showing a schematic configuration of the display device of Embodiment 1 shown in FIG. 1. FIG. 3 is a diagram comparing the luminous efficiency of a portion driven by a first electrode and a portion driven by a second electrode in each of a red light-emitting element, a green light-emitting element, and a blue light-emitting element provided in the display device of Embodiment 1. FIG. 4 is a diagram comparing the viewing angle characteristics when the display device of Embodiment 1 is driven in a wide viewing angle mode and when driven in a narrow viewing angle mode. FIG. 5 is a diagram showing a case where the viewing angle mode is switched by switching the drive electrode from one of the first electrode and the second electrode to the other in the display device of Embodiment 1. FIG. 6 is a cross-sectional view showing a schematic configuration of a display device of a first modified example of Embodiment 1. FIG. 7 is a plan view showing a schematic configuration of a display device of a second modified example of Embodiment 1 shown in FIG. 8. FIG. 9 is a diagram showing an example of a manufacturing process for the display device of Embodiment 1, the display device of the first modified example of Embodiment 1, and the display device of the second modified example of Embodiment 1. FIG. 10 is a cross-sectional view showing a schematic configuration of a display device of Embodiment 2. 1 is a diagram comparing the luminous efficiency of a portion driven by a first electrode and a portion driven by a second electrode in each of a red light-emitting element, a green light-emitting element, and a blue light-emitting element provided in the display device of Embodiment 2. FIG. 2 is a diagram showing that the viewing angle characteristics when the display device of Embodiment 2, which has a high refractive index second capping layer on the second electrode, is driven in a narrow viewing angle mode are improved compared to the viewing angle characteristics when the display device of Embodiment 1, which does not have a high refractive index second capping layer on the second electrode, is driven in a narrow viewing angle mode. FIG. 3 is a cross-sectional view showing a schematic configuration of a display device of Embodiment 3. FIG. 4 is a diagram comparing the luminous efficiency of a portion driven by a first electrode and a portion driven by a second electrode in each of a red light-emitting element, a green light-emitting element, and a blue light-emitting element provided in the display device of Embodiment 3. FIG. 5 is a diagram showing that the viewing angle characteristics when the display device of Embodiment 3, which has a low refractive index first capping layer on the first electrode, is driven in a wide viewing angle mode are improved compared to the viewing angle characteristics when the display device of Embodiment 1, which does not have a low refractive index first capping layer on the first electrode, is driven in a wide viewing angle mode.Fig. 10 is a cross-sectional view showing a schematic configuration of a display device of embodiment 4. Fig. 11 is a cross-sectional view showing a schematic configuration of a display device of embodiment 5. Fig. 12 is a diagram comparing the luminous efficiency of a portion driven by a first electrode and a portion driven by a second electrode in each of a tandem red light-emitting element, a tandem green light-emitting element, and a tandem blue light-emitting element provided in the display device of embodiment 5. Fig. 13 is a diagram comparing the viewing angle characteristics when the display device of embodiment 5 is driven in a wide viewing angle mode and when it is driven in a narrow viewing angle mode.

[0012] The following describes embodiments of the present disclosure with reference to Figures 1 to 20. For the sake of convenience, components having the same functions as those described in specific embodiments will be denoted by the same reference numerals, and their description may be omitted.

[0013] [Embodiment 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a display device 1 of Embodiment 1. FIG. 2 is a plan view showing a schematic configuration of the display device 1 of Embodiment 1 shown in FIG. 1. Note that FIG. 1 is a cross-sectional view taken along line A-A' in FIG. 2, and FIG. 2 illustrates only the semi-reflective common first electrode 12a, the semi-reflective common second electrode 12b, the red light-emitting layer 8R, the green light-emitting layer 8G, and the blue light-emitting layer 8B. FIG. 3 is a graph comparing the luminous efficiency of the portion driven by the first electrode 12a and the portion driven by the second electrode 12b in each of the red light-emitting element 20R, the green light-emitting element 20G, and the blue light-emitting element 20B provided in the display device 1 of Embodiment 1. FIG. 4 is a graph comparing the viewing angle characteristics when the display device 1 of Embodiment 1 is driven in a wide viewing angle mode with the viewing angle characteristics when driven in a narrow viewing angle mode. FIG. 5 is a diagram showing a case where the viewing angle mode is switched by switching the drive electrode from one of the first electrode 12a and the second electrode 12b to the other in the display device 1 of Embodiment 1.

[0014] As shown in Fig. 1, the display device 1 includes a plurality of pixels, each of which includes, for example, a red subpixel, a green subpixel, and a blue subpixel. The red subpixel includes a red light-emitting element 20R including a red light-emitting layer 8R, the green subpixel includes a green light-emitting element 20G including a green light-emitting layer 8G, and the blue subpixel includes a blue light-emitting element 20B including a blue light-emitting layer 8B. In this embodiment, a case in which one pixel is composed of a red subpixel, a green subpixel, and a blue subpixel is described as an example, but this is not limiting. For example, one pixel may include subpixels of other colors in addition to the red subpixel, the green subpixel, and the blue subpixel.

[0015] As shown in Fig. 1, blue light-emitting element 20B includes a semi-reflective first electrode 12a, a semi-reflective second electrode 12b that is thicker than semi-reflective first electrode 12a, a reflective third electrode 3B located in a layer separate from semi-reflective first electrode 12a and semi-reflective second electrode 12b, and a blue light-emitting layer (first light-emitting layer) 8B provided between semi-reflective first electrode 12a, semi-reflective second electrode 12b, and reflective third electrode 3B. Semi-reflective first electrode 12a overlaps a portion of blue light-emitting layer 8B and a portion of reflective third electrode 3B in a planar view, and semi-reflective second electrode 12b overlaps another portion of blue light-emitting layer 8B and another portion of reflective third electrode 3B in a planar view. As shown in Fig. 1, green light-emitting element 20G and red light-emitting element 20R each have a configuration similar to that of blue light-emitting element 20B described above, and therefore, description thereof will be omitted here.

[0016] The semi-reflective first electrode 12a and the semi-reflective second electrode 12b each have the property of transmitting a portion of the visible light generated in the blue light-emitting element 20B, the green light-emitting element 20G, and the red light-emitting element 20R and reflecting the remaining portion, and for example, an electrode having a visible light reflectance of 20% or more and 80% or less can be used. On the other hand, the reflective third electrode 3B, the reflective third electrode 3G, and the reflective third electrode 3R each have the property of mainly reflecting the visible light generated in the blue light-emitting element 20B, the green light-emitting element 20G, and the red light-emitting element 20R, and for example, an electrode having a visible light reflectance of 90% or more can be used.

[0017] 5 , a portion of each of the blue light-emitting elements 20B, green light-emitting elements 20G, and red light-emitting elements 20R driven with a semi-reflective second electrode 12b that is thicker than the semi-reflective first electrode 12a can achieve a narrow viewing angle, while a portion of each of the blue light-emitting elements 20B, green light-emitting elements 20G, and red light-emitting elements 20R driven with a semi-reflective first electrode 12a that is thinner than the semi-reflective second electrode 12b can achieve a wide viewing angle. Therefore, in each of the blue light-emitting elements 20B, green light-emitting elements 20G, and red light-emitting elements 20R, the viewing angle mode can be switched by switching the drive electrode from one of the first electrode 12a and the second electrode 12b to the other. In the display device 1 including the blue light-emitting elements 20B, green light-emitting elements 20G, and red light-emitting elements 20R, the viewing angle mode can also be switched by switching the drive electrode from one of the first electrode 12a and the second electrode 12b to the other.

[0018] As described above, in each of the blue light-emitting element 20B, the green light-emitting element 20G, and the red light-emitting element 20R, by using a semi-reflective first electrode 12a and a semi-reflective second electrode 12b that is thicker than the semi-reflective first electrode 12a, it is possible to change the viewing angle characteristics on the emission side of light from the light-emitting layer of the corresponding color, thereby realizing further improved wide viewing angle mode and narrow viewing angle mode.

[0019] In this embodiment, the case where each of the blue light-emitting layer 8B, the green light-emitting layer 8G, and the red light-emitting layer 8R is configured as a single island-shaped light-emitting layer will be described as an example, but the present invention is not limited to this. As shown in Fig. 1, a portion of each of the island-shaped blue light-emitting layer 8B, the island-shaped green light-emitting layer 8G, and the island-shaped red light-emitting layer 8R overlaps with the semi-reflective first electrode 12a in a planar view, and another portion of each of the island-shaped blue light-emitting layer 8B, the island-shaped green light-emitting layer 8G, and the island-shaped red light-emitting layer 8R overlaps with the semi-reflective second electrode 12b in a planar view.

[0020] 2 , in the display device 1 of the present embodiment, a plurality of pixels are provided along the first direction D1 and a second direction D2 perpendicular to the first direction D1, each pixel including a red light-emitting element 20R including a red light-emitting layer 8R, a green light-emitting element 20G including a green light-emitting layer 8G, and a blue light-emitting element 20B including a blue light-emitting layer 8B, which are arranged along the first direction D1 and the second direction D2 orthogonal to the first direction D1. The semi-reflective first electrode 12a of the red light-emitting element 20R, the semi-reflective first electrode 12a of the green light-emitting element 20G, and the semi-reflective first electrode 12a of the blue light-emitting element 20B in each of the plurality of pixels are provided as a semi-reflective common first electrode 12a, and the semi-reflective second electrode 12b of the red light-emitting element 20R, the semi-reflective second electrode 12b of the green light-emitting element 20G, and the semi-reflective second electrode 12b of the blue light-emitting element 20B in each of the plurality of pixels are provided as a semi-reflective common second electrode 12b. 2, the display device 1 of the present embodiment includes a first pixel, a second pixel, and a third pixel arranged in this order along the second direction D2 as three adjacent pixels in the second direction D2, and the semi-reflective first common electrode 12a of the second pixel is connected to the semi-reflective first common electrode 12a of the first pixel, and the semi-reflective second electrode 12b of the second pixel is connected to the semi-reflective second common electrode 12b of the third pixel.

[0021] In this embodiment, as shown in FIG. 1 , in each of the red light-emitting element 20R, the green light-emitting element 20G, and the blue light-emitting element 20B, the semi-reflective first electrode 12a and the semi-reflective second electrode 12b are provided above the light-emitting layer of the corresponding color, and the reflective third electrodes 3B, 3G, and 3R are provided below the light-emitting layer of the corresponding color. That is, in this embodiment, the red light-emitting element 20R, the green light-emitting element 20G, and the blue light-emitting element 20B are each a top-emission type light-emitting element. While not limited to this, and although not shown, in each of the red light-emitting element 20R, the green light-emitting element 20G, and the blue light-emitting element 20B, the reflective third electrodes 3B, 3G, and 3R may be provided above the light-emitting layer of the corresponding color, and the semi-reflective first electrode 12a and the semi-reflective second electrode 12b may be provided below the light-emitting layer of the corresponding color. That is, each of the red light emitting element 20R, the green light emitting element 20G, and the blue light emitting element 20B may be a bottom emission type light emitting element.

[0022] 1 includes a transistor layer (not shown) including a plurality of thin film transistors. In this embodiment, the red light emitting element 20R, the green light emitting element 20G, and the blue light emitting element 20B are each a top-emission light emitting element, and therefore, the drain electrode of the thin film transistor for driving the blue light emitting element 20B among the plurality of thin film transistors is electrically connected to the reflective third electrode 3B provided for the blue light emitting element 20B, the drain electrode of the thin film transistor for driving the green light emitting element 20G among the plurality of thin film transistors is electrically connected to the reflective third electrode 3G provided for the green light emitting element 20G, and the drain electrode of the thin film transistor for driving the red light emitting element 20R among the plurality of thin film transistors is electrically connected to the reflective third electrode 3R provided for the red light emitting element 20R. On the other hand, when the red light emitting element 20R, the green light emitting element 20G, and the blue light emitting element 20B are bottom emission type light emitting elements, although not shown, the drain electrode of a first thin film transistor for driving the blue light emitting element 20B among the plurality of thin film transistors is electrically connected to the semi-reflective first electrode 12a provided on the blue light emitting element 20B, the drain electrode of a second thin film transistor for driving the blue light emitting element 20B among the plurality of thin film transistors is electrically connected to the semi-reflective second electrode 12b provided on the blue light emitting element 20B, and the drain electrode of a first thin film transistor for driving the green light emitting element 20G among the plurality of thin film transistors is electrically connected to the semi-reflective second electrode 12b provided on the green light emitting element 20B. The drain electrode of the second thin film transistor for driving the green light emitting element 20G among the plurality of thin film transistors is electrically connected to the semi-reflective first electrode 12a provided on the green light emitting element 20G, the drain electrode of the first thin film transistor for driving the red light emitting element 20R among the plurality of thin film transistors is electrically connected to the semi-reflective first electrode 12a provided on the red light emitting element 20R, and the drain electrode of the second thin film transistor for driving the red light emitting element 20R among the plurality of thin film transistors is electrically connected to the semi-reflective second electrode 12b provided on the red light emitting element 20R.

[0023] 1, the display device 1 is described as having edge covers 4 that cover the edges of the reflective third electrodes 3B, 3G, and 3R, but is not limited to this and may not have the edge covers 4. The edge covers 4 can be formed, for example, by applying an organic material such as polyimide or acrylic and then patterning it by photolithography.

[0024] 1, the display device 1 includes a non-light-emitting portion ML that overlaps the edge cover 4 in a plan view. The non-light-emitting portion ML can be formed by stacking, for example, two or more layers of the second charge blocking layers 7R, 7G, and 7B and two or more layers of the red light-emitting layer 8R, the green light-emitting layer 8G, and the blue light-emitting layer 8B.

[0025] 1 , blue light-emitting element 20B includes a reflective third electrode 3B, a semi-reflective first electrode 12a, and a semi-reflective second electrode 12b, and between these electrodes, from the reflective third electrode 3B side, are provided, in this order, a first charge injection layer 5, a first charge transport layer 6, a second charge blocking layer 7B, a blue light-emitting layer 8B, a first charge blocking layer 9, a second charge transport layer 10, and a second charge injection layer 11. A stack of first charge injection layer 5, first charge transport layer 6, second charge blocking layer 7B, blue light-emitting layer 8B, first charge blocking layer 9, second charge transport layer 10, and second charge injection layer 11 is a functional layer 19B including blue light-emitting layer 8B.

[0026] 1 , green light-emitting element 20G includes a reflective third electrode 3G, a semi-reflective first electrode 12a, and a semi-reflective second electrode 12b, and between these electrodes, from the reflective third electrode 3G side, are provided a first charge injection layer 5, a first charge transport layer 6, a second charge blocking layer 7G, a green light-emitting layer 8G, a first charge blocking layer 9, a second charge transport layer 10, and a second charge injection layer 11 in this order. A laminate of the first charge injection layer 5, the first charge transport layer 6, the second charge blocking layer 7G, the green light-emitting layer 8G, the first charge blocking layer 9, the second charge transport layer 10, and the second charge injection layer 11 is a functional layer 19G including the green light-emitting layer 8G.

[0027] 1 , red light-emitting element 20R includes a reflective third electrode 3R, a semi-reflective first electrode 12a, and a semi-reflective second electrode 12b, and between these electrodes, from the reflective third electrode 3R side, are provided a first charge injection layer 5, a first charge transport layer 6, a second charge blocking layer 7R, a red light-emitting layer 8R, a first charge blocking layer 9, a second charge transport layer 10, and a second charge injection layer 11 in this order. A laminate of the first charge injection layer 5, the first charge transport layer 6, the second charge blocking layer 7R, the red light-emitting layer 8R, the first charge blocking layer 9, the second charge transport layer 10, and the second charge injection layer 11 is a functional layer 19R including the red light-emitting layer 8R.

[0028] In this embodiment, the reflective third electrode 3B provided in the blue light-emitting element 20B, the reflective third electrode 3G provided in the green light-emitting element 20G, and the reflective third electrode 3R provided in the red light-emitting element 20R are each used as an anode, and a case will be described in which an ITO (indium tin oxide) layer, an Ag layer, and an ITO (indium tin oxide) layer are stacked. However, there is no particular limitation as long as the electrode can reflect visible light and is conductive.

[0029] In this embodiment, the semi-reflective first electrode 12a and the semi-reflective second electrode 12b of the blue light-emitting element 20B, the semi-reflective first electrode 12a and the semi-reflective second electrode 12b of the green light-emitting element 20G, and the semi-reflective first electrode 12a and the semi-reflective second electrode 12b of the red light-emitting element 20R are formed using a magnesium-silver mixture, and the semi-reflective first electrode 12a is formed to a thickness of 15 nm, and the semi-reflective second electrode 12b is formed to a thickness of 80 nm. However, this is not a limitation. The semi-reflective first electrode 12a and the semi-reflective second electrode 12b may also be formed using a magnesium-aluminum mixture or aluminum, for example. Furthermore, the thickness of the semi-reflective second electrode 12b is not limited to the above-mentioned thicknesses as long as it is thicker than the semi-reflective first electrode 12a.

[0030] In this embodiment, a first charge injection layer 5 having a thickness of 10 nm is formed as a hole injection layer using a hole transport material (for example, a triphenylamine-based compound) and an electron accepting material (for example, TCNQ-4F), a first charge transport layer 6 having a thickness of 100 nm is formed as a hole transport layer using a hole transport material (for example, a triphenylamine-based compound), a second charge blocking layer 7B having a thickness of 5 nm is formed as an electron blocking layer using, for example, a carbazole-based compound, and a host material (for example, a perylene-based compound) and a dopant material (for example, an anthracene-based compound). A 20-nm-thick blue light-emitting layer 8B is formed using a phenanthroline compound, a 10-nm-thick first charge blocking layer 9 is formed as a hole blocking layer using, for example, a phenanthroline compound, a 25-nm-thick second charge transport layer 10 is formed as an electron transport layer using an electron transport material (e.g., an oxadiazole compound) and Liq, and a 3-nm-thick second charge injection layer 11 is formed as an electron injection layer using, for example, lithium fluoride (LiF). This completes the functional layer 19B including the blue light-emitting layer 8B provided in the blue light-emitting element 20B, but the present invention is not limited thereto. In this embodiment, the blue light-emitting layer 8B is formed of an organic light-emitting material. However, the blue light-emitting layer 8B may be, for example, a light-emitting layer including quantum dots. Furthermore, layers other than the blue light-emitting layer 8B may be omitted from the functional layer 19B including the blue light-emitting layer 8B, as appropriate.

[0031] In this embodiment, a first charge injection layer 5 having a thickness of 10 nm is formed as a hole injection layer using a hole transport material (for example, a triphenylamine-based compound) and an electron accepting material (for example, TCNQ-4F). A first charge transport layer 6 having a thickness of 100 nm is formed as a hole transport layer using a hole transport material (for example, a triphenylamine-based compound). As an electron blocking layer, a second charge blocking layer 7G is formed as a laminate having a thickness of 30 nm, in which, from the first charge transport layer 6 side, a first layer formed using a carbazole-based compound and a second layer formed using a triphenylamine-based compound are laminated in this order. A 35-nm-thick green light-emitting layer 8G is formed using a mixed compound of a carrier compound and a dopant material (e.g., an iridium complex compound (green light emission)). A 10-nm-thick first charge blocking layer 9 is formed as a hole blocking layer using, for example, a phenanthroline compound. A 25-nm-thick second charge transport layer 10 is formed as an electron transport layer using, for example, an electron transport material (e.g., an oxadiazole compound) and Liq. A 3-nm-thick second charge injection layer 11 is formed as an electron injection layer using, for example, lithium fluoride (LiF). Thus, a functional layer 19G including the green light-emitting layer 8G provided in the green light-emitting element 20G is formed, but the present invention is not limited thereto. In this embodiment, the case where the green light-emitting layer 8G is formed of an organic light-emitting material has been described as an example. However, the green light-emitting layer 8G may be, for example, a light-emitting layer including quantum dots. Furthermore, layers other than the green light-emitting layer 8G may be omitted from the functional layer 19G including the green light-emitting layer 8G, as appropriate.

[0032] In this embodiment, a first charge injection layer 5 having a thickness of 10 nm is formed as a hole injection layer using a hole transport material (for example, a triphenylamine-based compound) and an electron accepting material (for example, TCNQ-4F), a first charge transport layer 6 having a thickness of 100 nm is formed as a hole transport layer using a hole transport material (for example, a triphenylamine-based compound), and a second charge blocking layer 7R having a thickness of 80 nm is formed by laminating, for example, a first layer formed using a carbazole-based compound and a second layer formed using a triphenylamine-based compound from the first charge transport layer 6 side in this order. A red light-emitting layer 8R having a thickness of 35 nm is formed using a mixed compound of tetrachloroethylene and a dopant material (e.g., an iridium complex compound (red light emission)). A first charge blocking layer 9 having a thickness of 10 nm is formed as a hole blocking layer using, for example, a phenanthroline compound. A second charge transport layer 10 having a thickness of 25 nm is formed as an electron transport layer using, for example, an electron transport material (e.g., an oxadiazole compound) and Liq. A second charge injection layer 11 having a thickness of 3 nm is formed as an electron injection layer using, for example, lithium fluoride (LiF). This forms a functional layer 19R including the red light-emitting layer 8R provided in the red light-emitting element 20R. However, the present invention is not limited to this. In this embodiment, the red light-emitting layer 8R is formed of an organic light-emitting material as an example. However, the red light-emitting layer 8R may be, for example, a light-emitting layer including quantum dots. Furthermore, layers other than the red light-emitting layer 8R may be omitted from the functional layer 19R including the red light-emitting layer 8R, as appropriate.

[0033] In this embodiment, the blue light-emitting element 20B has a microcavity structure formed by a semi-reflective first electrode 12a and a semi-reflective second electrode 12b, a functional layer 19B including a blue light-emitting layer 8B, and a reflective third electrode 3B; the green light-emitting element 20G has a microcavity structure formed by a semi-reflective first electrode 12a and a semi-reflective second electrode 12b, a functional layer 19G including a green light-emitting layer 8G, and a reflective third electrode 3G; and the red light-emitting element 20R has a microcavity structure formed by a semi-reflective first electrode 12a and a semi-reflective second electrode 12b, a functional layer 19R including a red light-emitting layer 8R, and a reflective third electrode 3R. This example is intended to illustrate, but is not limited to, this example. In this embodiment, the film thickness of functional layer 19B including blue light-emitting layer 8B, i.e., the first distance D1B between surface 12as of semi-reflective first electrode 12a on the light-emitting layer side and surface 3Bs of reflective third electrode 3B on the light-emitting layer side, and the second distance D2B between surface 12bs of semi-reflective second electrode 12b on the light-emitting layer side and surface 3Bs of reflective third electrode 3B, are 173 nm. The film thickness of functional layer 19G including green light-emitting layer 8G, i.e., the first distance D1B between surface 12as of semi-reflective first electrode 12a on the light-emitting layer side and surface 3Gs of reflective third electrode 3G on the light-emitting layer side, and the second distance D2B between surface 12bs of semi-reflective second electrode 12b on the light-emitting layer side and surface 3Gs of reflective third electrode 3G on the light-emitting layer side, are 173 nm. a first distance D1G between the light-emitting layer-side surface 12as of the semi-reflective second electrode 12b and the light-emitting layer-side surface 3Gs of the reflective third electrode 3G is 213 nm, and a second distance D2G between the light-emitting layer-side surface 12as of the semi-reflective first electrode 12a and the light-emitting layer-side surface 3Rs of the reflective third electrode 3R is 273 nm.The film thickness of the functional layer 19B including the above-mentioned blue light-emitting layer 8B, i.e., the first distance D1B and the second distance D2B, are optimal values ​​for resonating and induced emission of light in the blue wavelength region, the film thickness of the functional layer 19G including the above-mentioned green light-emitting layer 8G, i.e., the first distance D1G and the second distance D2G, are optimal values ​​for resonating and induced emission of light in the green wavelength region, and the film thickness of the functional layer 19R including the above-mentioned red light-emitting layer 8R, i.e., the first distance D1R and the second distance D2R, are optimal values ​​for resonating and induced emission of light in the red wavelength region. Therefore, the half-widths of the spectra of the light emitted from each of the blue light-emitting elements 20B, green light-emitting elements 20G, and red light-emitting elements 20R provided in the display device 1 are reduced, which has the advantage of emitting light with deep chromaticity.

[0034] The materials used in the processes for forming the functional layer 19B including the blue light-emitting layer 8B, the functional layer 19G including the green light-emitting layer 8G, and the functional layer 19R including the red light-emitting layer 8R described above are not limited to those described above, and may be formed using, for example, the materials described below.

[0035] For example, materials for forming the blue-emitting layer 8B include fluorescent dopants such as pyrene-based compounds and anthracene-based compounds. Materials for forming the red-emitting layer 8R and the green-emitting layer 8B include phosphorescent dopants such as iridium complexes, palladium-based complexes, or platinum-based complexes. Complexes containing iridium, palladium, or platinum-based elements used as phosphorescent dopants are extremely expensive even in small amounts, due to the limited production volume and uneven distribution of these metal elements, and stable supply can be difficult. Therefore, reducing the amount of phosphorescent dopants using these metal complexes is extremely important from the perspectives of cost reduction and economic security. In this way, a host-guest emitting layer can be formed by doping a guest compound into a host compound. A host-guest emitting layer can be formed by a co-evaporation method using multiple evaporation sources. Various known examples of materials for the host-guest emitting layer can be used. Examples of the host compound include known light-emitting layer materials of each color (here, known refers to hole transport materials, electron transport materials, materials described as guest compounds, etc.). Examples of the guest compound include the above-mentioned fluorescent dopants and phosphorescent dopants, as well as TADF and hyperfluorescent materials. Further examples of fluorescent dopants include the above-mentioned pyrene-based and anthracene-based compounds, as well as perylene, DPT, Coumarin 6, PMDFB, quinacridone, rubrene, BTX, ABTX, DCM, and DCJT. Further examples of phosphorescent dopants include Ir(ppy) for iridium complexes. ３ , Ir(thpy) ３ , Ir(t5m-thpy) ３ , Ir(t-5CF ３ -py) ３ , Ir(t-5t-py) ３ , Ir(mt-5mt-py) ３ , Ir(btpy) ３ , Ir(tflpy) ３ , Ir(piq) ３ , Ir(tiq) ３ , Ir(fliq) ３, FIrpic, FIr6, Ir(ppy), Ir(tpy), Ir(bzq), Ir(thp), Ir(op), Ir(bo), Ir(bt), Ir(bon), Ir(αbsn), Ir(btp), Ir(ppo), Ir(C6), Ir(pq), Ir(β-bsn), Ir(ppz), and the like, and platinum complexes include PtON-TBBI, PtON7-t-Bu, PtOEP, and the like.

[0036] Examples of the hole transport material include polyethylenedioxythiophene doped with polystyrene sulfonic acid (PEDOT:PSS), 4,4',4''-tris(9-carbazoyl)triphenylamine (TCTA), 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]-biphenyl (NPB), zinc phthalocyanine (ZnPC), di[4-(N,N-ditolylamino)phenyl]cyclohexane (TAPC), 4,4'-bis(carbazo Examples of such materials include 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (CBP), 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN), poly(N-vinylcarbazole) (PVK), poly(2,7-(9,9-di-n-octylfluorene))-(1,4-phenylene-(4-sec-butylphenyl)imino)-1,4-phenylene (TFB), and poly(triphenylamine) derivatives (Poly-TPD).

[0037] The material for forming the electron blocking layer, like the material for forming the hole transport layer, can be an organic or inorganic hole transport material. The material for forming the electron blocking layer may be the same as or different from the material for forming the hole transport layer.

[0038] The material forming the hole injection layer may be composed of, for example, a hole transport material and an electron accepting material (hole supply material). The material forming the hole injection layer, like the material forming the hole transport layer, may be an inorganic or organic material. The specific material of the hole injection layer may be the same as or different from the material of the hole generation layer described below.

[0039] The material for forming the hole injection layer can be a material containing an organic hole transport material and an organic electron accepting material (hole supply material) added in the range of 1 to 10%. Known triarylamine organic compounds can be used as the organic hole transport material. Examples of organic electron accepting materials include TCNQ (tetracyanoquinodimethane), TNAP (tetracyano-2,6-naphthoquinodimethane), DCNQI (dicyanoquinomethane), TCNQ-4F (1,2,3,4-fluorinated tetracyanoquinodimethane), TNAP-4F (1,2,3,4,5,6-fluorinated tetracyano-2,6-naphthoquinodimethane), DCTCNQ (dicyanotetracyanoquinodimethane), and the like. The hole transport material and electron accepting material may be used to form a hole injection layer having sufficient hole injection capability.

[0040] The materials forming the electron injection layer and electron transport layer described above include an electron transport material that contributes to electron transport. The electron transport material may be an inorganic electron transport material or an organic electron transport material. The electron transport material can be appropriately selected from materials commonly used in this field. Examples of inorganic electron transport materials include metal oxides containing one or more metal elements selected from the group consisting of Zn, Ti, Mg, Zr, Sn, and Nb. These materials may be in the form of nanoparticles. Examples of organic electron transport materials include compounds and complexes containing one or more nitrogen-containing heterocycles such as an oxadiazole ring, a triazole ring, a triazine ring, a quinoline ring, a phenanthroline ring, a pyrimidine ring, a pyridine ring, an imidazole ring, or a carbazole ring. Specific examples include 1,10-phenanthroline derivatives such as bathocuproine and bathophenanthroline, benzimidazole derivatives such as 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI), metal complexes such as bis(10-benzoquinolinolato)beryllium complex, 8-hydroxyquinoline Al complex, and bis(2-methyl-8-quinolinato)-4-phenylphenolate aluminum, and 4,4′-biscarbazole biphenyl.

[0041] The material forming the hole blocking layer may be an inorganic or organic electron transport material, such as a metal oxide containing one or more metal elements selected from the group consisting of Zn, Ti, Mg, Zr, Sn, and Nb, an oxadiazole-based compound, and a phenanthroline-based compound. The material forming the hole blocking layer may contain lithium quinoline (Liq) in addition to the electron transport material. The hole blocking layer is an insulating layer through which holes have difficulty passing, and may contain an electron transport material.

[0042] Materials for forming the electron injection layer include, for example, lithium fluoride (LiF), which is an inorganic material. The electron injection layer may be formed solely from organic materials such as oxadiazole-based compounds, or may be formed by doping an organic material with a metal material (e.g., Li or Yb), or may be formed solely from a metal material (e.g., Li or Yb). LiF used in the electron injection layer exhibits excellent electron injection properties. Meanwhile, the formation of a carrier functional layer containing an inorganic material such as LiF or Yb is generally carried out at a higher temperature than the formation of an emitting layer and other carrier functional layers made of organic materials due to the high melting point of the inorganic material. Therefore, thermal damage may be caused to previously formed organic materials and (near-)infrared emitting materials. Therefore, if possible, it is preferable to form a light-emitting element solely from organic materials, without including inorganic materials. Even when the electron injection layer is formed solely from organic materials, high electron injection properties are maintained by including metals such as Yb, Li, and Al in the cathode.

[0043] By combining it with a cathode made of aluminum (Al), which can form a vapor deposition layer at a relatively low temperature, it can have sufficient properties. As an all-organic electron injection layer, BUPH1, BPen, p-MeO-Phen, p-NMe ２ Development of organic electron injection materials such as p-Pyrrd-Phen and p-Pyrrd-Phen is underway. However, the electron injection ability of an electron injection layer using an organic material may be inferior to that of an electron injection layer using an inorganic material such as LiF. Therefore, when an electron injection layer made of an organic material is disposed adjacent to the cathode, the amount of carriers supplied (electron supply amount) from the cathode side to the light-emitting layer may decrease. In such cases, the amount of carriers supplied (hole supply amount) from the anode side to the light-emitting layer may be appropriately adjusted to achieve a balance.

[0044] The sealing layer 13 shown in FIG. 1 is a light-transmitting film and may be composed of, for example, a first inorganic sealing film covering the semi-reflective first electrode 12a and the semi-reflective second electrode 12b, an organic film layered above the first inorganic sealing film, and a second inorganic sealing film layered above the organic film. The sealing layer 13 prevents foreign substances such as water and oxygen from penetrating into the red light-emitting element 20R, the green light-emitting element 20G, and the blue light-emitting element 20B. The first inorganic sealing film and the second inorganic sealing film are each inorganic films and may be composed of, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a laminate film thereof formed by a CVD method. The organic film is a light-transmitting organic film with a planarizing effect and may be composed of a coatable organic material such as acrylic. The organic film may also be formed by, for example, an inkjet method. In this embodiment, the sealing layer 13 is formed of two inorganic films and one organic film disposed between the two inorganic films, but the stacking order of the two inorganic films and the one organic film is not limited to this. Furthermore, the sealing layer 13 may be formed only of inorganic films, or only of organic films, or may be formed of one inorganic film and two organic films, or two or more inorganic films and two or more organic films.

[0045] As shown in Figure 3, in each of the red light-emitting element 20R, green light-emitting element 20G, and blue light-emitting element 20B provided in the display device 1, even though the film thickness of the first electrode 12a and the film thickness of the second electrode 12b are different, the light-emitting efficiency of the part driven by the first electrode 12a and the part driven by the second electrode 12b is at approximately the same level.

[0046] As shown in FIG. 4, when the viewing angle characteristics of a pixel including a red light-emitting element 20R, a green light-emitting element 20G, and a blue light-emitting element 20B driven in a wide viewing-angle mode under white light emission conditions are compared with the viewing angle characteristics of a pixel driven in a narrow viewing-angle mode, a wide viewing-angle characteristic is obtained in the wide viewing-angle mode driven by the first electrode 12a, and a high brightness is obtained in the front direction in the narrow viewing-angle mode driven by the second electrode 12b.

[0047] In this embodiment, for each of the red light-emitting element 20R, the green light-emitting element 20G, and the blue light-emitting element 20B, the area where the semi-reflective first electrode 12a, the reflective third electrode 3R, 3G, and 3B, and the light-emitting layer 8R, 8G, and 8B of the corresponding color overlap in a planar view is defined as a first area, and the area where the semi-reflective second electrode 12b, the reflective third electrode 3R, 3G, and 3B, and the light-emitting layer 8R, 8G, and 8B of the corresponding color overlap in a planar view is defined as a second area. Here, the value of ((first area) / (first area + second area)) × 100(%) is 50%, but is not limited to this. The value of ((first area) / (first area + second area)) × 100(%) is preferably 10% or more and 90% or less, more preferably 25% or more and 75% or less, and most preferably 40% or more and 60% or less. Furthermore, when the luminous efficiency in the wide viewing angle mode and the narrow viewing angle mode are equivalent, the front luminance in the wide viewing angle mode is lower than that in the narrow viewing angle mode, and therefore, from the viewpoint of minimizing the difference in front luminance and reducing the sense of incongruity in appearance, it is preferable to make the first area, which is the area driven in the wide viewing angle mode, larger than the second area, which is the area driven in the narrow viewing angle mode. Note that the front luminance means luminance in the front direction, and the front direction means a direction within a viewing angle range of 3 degrees or less in all directions from the normal direction to the light-emitting surface.

[0048] In this embodiment, as described above, the display device 1 equipped with red light-emitting elements 20R, green light-emitting elements 20G, and blue light-emitting elements 20B has been described as an example, but this is not limited to this, and the same effects as the display device 1 described above can be obtained with a light-emitting device equipped with red light-emitting elements 20R, green light-emitting elements 20G, and blue light-emitting elements 20B, a light-emitting device equipped with only a plurality of red light-emitting elements 20R, a light-emitting device equipped with only a plurality of green light-emitting elements 20G, and a light-emitting device equipped with only a plurality of blue light-emitting elements 20B.

[0049] 1 , the driving method of each of the red light emitting element 20R, the green light emitting element 20G, and the blue light emitting element 20B includes a wide viewing angle mode in which only a first region where the semi-reflective first electrode 12a, a portion of the light emitting layer 8R, 8G, or 8B of the corresponding color, and a portion of the reflective third electrode 3R, 3G, or 3B overlap in a planar view, emits light, and a narrow viewing angle mode in which only a second region where the semi-reflective second electrode 12b, another portion of the light emitting layer 8R, 8G, or 8B of the corresponding color, and another portion of the reflective third electrode 3R, 3G, or 3B overlap in a planar view, emits light. The driving method of each of the red light emitting element 20R, the green light emitting element 20G, and the blue light emitting element 20B may further include a general mode in which the first region and the second region emit light simultaneously.

[0050] Fig. 6 is a cross-sectional view showing a schematic configuration of a display device 1a according to a first modified example of embodiment 1. Fig. 7 is a plan view showing a schematic configuration of the display device 1a according to the first modified example of embodiment 1 shown in Fig. 6. Note that Fig. 6 is a cross-sectional view taken along line BB' in Fig. 7, and Fig. 7 shows only the semi-reflective common first electrode 12a, the semi-reflective common second electrode 12b, the red light-emitting layer 8R, the green light-emitting layer 8G, and the blue light-emitting layer 8B.

[0051] 6 and 7 , the display device 1a includes a plurality of pixels arranged along the first direction D1 and a second direction D2 perpendicular to the first direction D1, the pixels including red light-emitting elements 20Ra including red light-emitting layers 8R, green light-emitting elements 20Ga including green light-emitting layers 8G, and blue light-emitting elements 20Ba including blue light-emitting layers 8B. The pixels include red light-emitting elements 20Ra including red light-emitting layers 8R, green light-emitting elements 20Ga including green light-emitting layers 8G, and blue light-emitting elements 20Ba including blue light-emitting layers 8B. The semi-reflective first electrodes 12a of the red light-emitting elements 20Ra, the semi-reflective first electrodes 12a of the green light-emitting elements 20Ga, and the semi-reflective first electrodes 12a of the blue light-emitting elements 20Ba in each of the plurality of pixels are provided as a semi-reflective common first electrode 12a, and the semi-reflective second electrodes 12b of the red light-emitting elements 20Ra, the semi-reflective second electrodes 12b of the green light-emitting elements 20Ga, and the semi-reflective second electrodes 12b of the blue light-emitting elements 20Ba in each of the plurality of pixels are provided as a semi-reflective common second electrode 12b. In plan view, semi-reflective common first electrodes 12a and semi-reflective common second electrodes 12b are alternately provided in both the first direction D1 and the second direction D2.

[0052] Fig. 8 is a cross-sectional view showing a schematic configuration of a display device 1b according to a second modified example of embodiment 1. Fig. 9 is a plan view showing a schematic configuration of the display device 1b according to the second modified example of embodiment 1 shown in Fig. 8. Note that Fig. 9 shows only the semi-reflective common first electrode 12a, the semi-reflective common second electrode 12b, the red light-emitting layers 8R and 8R', the green light-emitting layers 8G and 8G', and the blue light-emitting layers 8B and 8B'.

[0053] 8, the display device 1b includes a blue light-emitting element 20Bb, a green light-emitting element 20Gb, and a red light-emitting element 20Rb. The blue light-emitting element 20Bb includes two island-shaped blue light-emitting layers 8B and 8B'. The island-shaped blue light-emitting layer 8B overlaps the semi-reflective first electrode 12a in a planar view, and the island-shaped blue light-emitting layer 8B' overlaps the semi-reflective second electrode 12b in a planar view. The green light-emitting element 20Gb includes two island-shaped green light-emitting layers 8G and 8G'. The island-shaped green light-emitting layer 8G overlaps the semi-reflective first electrode 12a in a planar view, and the island-shaped green light-emitting layer 8G' overlaps the semi-reflective second electrode 12b in a planar view. The red light-emitting element 20Rb has two island-shaped red light-emitting layers 8R and 8R', and the island-shaped red light-emitting layer 8R overlaps with the semi-reflective first electrode 12a in a planar view, and the island-shaped red light-emitting layer 8R' overlaps with the semi-reflective second electrode 12b in a planar view.

[0054] 9 , in the display device 1b, the semi-reflective first electrodes 12a of the red light-emitting elements 20Rb, the semi-reflective first electrodes 12a of the green light-emitting elements 20Gb, and the semi-reflective first electrodes 12a of the blue light-emitting elements 20Bb, which are arranged along a first direction D1, are provided as a semi-reflective common first electrode 12a extending in the first direction D1, and the semi-reflective second electrodes 12b of the red light-emitting elements 20Rb, the semi-reflective second electrodes 12b of the green light-emitting elements 20Gb, and the semi-reflective second electrodes 12b of the blue light-emitting elements 20Bb, which are arranged along the first direction D1, are provided as a semi-reflective common second electrode 12b extending in the first direction D1. In addition, in a plan view, the semi-reflective common first electrodes 12a and the semi-reflective common second electrodes 12b are alternately arranged in a second direction D2 intersecting the first direction D1.

[0055] FIG. 10 is a diagram showing an example of a manufacturing process for the display device 1 of the first embodiment, the display device 1a of the first modified example of the first embodiment, and the display device 1b of the second modified example of the first embodiment.

[0056] As shown in FIG. 10 , the manufacturing process of the display device 1 of Embodiment 1, the display device 1a of the first modified example of Embodiment 1, and the display device 1b of the second modified example of Embodiment 1 includes the steps of: forming third electrodes 3R, 3G, and 3B (S1); forming first charge injection layers (hole injection layers) 5 (S2); forming first charge transport layers (hole transport layers) 6 (S3); forming second charge blocking layers (electron blocking layers) 7R, 7G, and 7B (S4); forming light-emitting layers (red light-emitting layer, green light-emitting layer, and blue light-emitting layer) 8R, 8G, and 8B (S5); forming first charge blocking layers (hole blocking layers) 9 (S6); forming second charge transport layers (electron transport layers) 10 (S7); forming second charge injection layers (electron injection layers) 11 (S8); forming first electrodes 12a and second electrodes 12b (S9); and forming sealing layer 13 (S10). A step of forming the edge cover 4 may be included between the step (S1) and the step (S2).

[0057] In the step (S1) of forming the third electrodes 3R, 3G, and 3B, an ITO (indium tin oxide) layer, an Ag layer, and an ITO (indium tin oxide) layer were laminated by sputtering. In the step (S2) of forming the first charge injection layer (hole injection layer) 5, a hole transport material and an electron acceptor material were co-evaporated at a predetermined temperature and a predetermined evaporation rate without a fine metal mask, thereby forming a first charge injection layer (hole injection layer) 5 common to the light-emitting elements of each color. In the step (S3) of forming the first charge transport layer (hole transport layer) 6, a hole transport material was evaporated at a predetermined temperature and a predetermined evaporation rate without a fine metal mask, thereby forming a first charge transport layer (hole transport layer) 6 common to the light-emitting elements of each color. In the step (S4) of forming second charge blocking layers (electron blocking layers) 7R, 7G, and 7B, deposition was performed sequentially for each light-emitting element of each color at a predetermined temperature and a predetermined deposition rate using a fine metal mask to form the second charge blocking layers (electron blocking layers) 7R, 7G, and 7B. In the step (S5) of forming light-emitting layers (red, green, and blue light-emitting layers) 8R, 8G, and 8B, deposition was performed sequentially for each light-emitting element of each color at a predetermined temperature and a predetermined deposition rate using a fine metal mask to form the light-emitting layers (red, green, and blue light-emitting layers) 8R, 8G, and 8B. In the step (S6) of forming first charge blocking layers (hole blocking layers) 9, deposition of an electron transport material was performed at a predetermined temperature and a predetermined deposition rate without a fine metal mask to form the first charge blocking layer (hole blocking layer) 9 common to each light-emitting element of each color. In the step (S7) of forming the second charge transport layer (electron transport layer) 10, vapor deposition of an electron transport material or co-deposition of an electron transport material and lithium quinoline was performed at a predetermined temperature and a predetermined vapor deposition rate without a fine metal mask, thereby forming the second charge transport layer (electron transport layer) 10 common to the light-emitting elements of each color. In the step (S8) of forming the second charge injection layer (electron injection layer) 11, vapor deposition of LiF or Yb was performed at a predetermined temperature and a predetermined vapor deposition rate without a fine metal mask, thereby forming the second charge injection layer (electron injection layer) 11 common to the light-emitting elements of each color.In the step (S9) of forming the first electrode 12a and the second electrode 12b, a mixture of magnesium and silver was evaporated at a predetermined temperature and a predetermined evaporation rate using a mask so that two types of electrodes with different film thicknesses were formed. In the step (S10) of forming the sealing layer 13, each film constituting the sealing layer 13 was evaporated or applied without using a fine metal mask.

[0058] [Embodiment 2] Fig. 11 is a cross-sectional view showing a schematic configuration of a display device 1c of Embodiment 2. Fig. 12 is a diagram comparing the luminous efficiency of the portion driven by the first electrode 12a and the portion driven by the second electrode 12b in each of the red light-emitting element 20Rc, the green light-emitting element 20Gc, and the blue light-emitting element 20Bc provided in the display device 1c of Embodiment 2. Fig. 13 is a diagram showing that the viewing angle characteristics when the display device 1c of Embodiment 2, which includes a high-refractive index second capping layer 14b on the second electrode 12b, is driven in the narrow-viewing-angle mode are improved compared to the viewing angle characteristics when the display devices 1, 1a, and 1b of Embodiment 1, which do not include a high-refractive index second capping layer 14b on the second electrode 12b, are driven in the narrow-viewing-angle mode.

[0059] 11 , in each of the red light-emitting element 20Rc, the green light-emitting element 20Gc, and the blue light-emitting element 20Bc provided in the display device 1c, a first capping layer 14a is provided on the semi-reflective first electrode 12a so as to overlap with the semi-reflective first electrode 12a in a planar view, and a second capping layer 14b is provided on the semi-reflective second electrode 12b so as to overlap with the semi-reflective second electrode 12b in a planar view, and the refractive index of the first capping layer 14a and the refractive index of the second capping layer 14b are different. In this embodiment, a case where the first capping layer 14a is formed using a material with a refractive index of 1.65 and the second capping layer 14b is formed using a material with a refractive index of 2.0 will be described as an example, but the present invention is not limited to this.

[0060] As shown in Figure 11, in each of the red light-emitting element 20Rc, green light-emitting element 20Gc, and blue light-emitting element 20Bc provided in the display device 1c, a film 15 made of lithium fluoride is formed on each of the first capping layer 14a and second capping layer 14b.

[0061] In the present embodiment, the case where the red light emitting element 20Rc, the green light emitting element 20Gc, and the blue light emitting element 20Bc are each a top-emission type light emitting element will be described as an example, but the present invention is not limited to this, and although not shown, in each of the red light emitting element 20Rc, the green light emitting element 20Gc, and the blue light emitting element 20Bc, the reflective third electrodes 3B, 3G, and 3R may be provided above the light emitting layer of the corresponding color, and the semi-reflective first electrode 12a and the semi-reflective second electrode 12b may be provided below the light emitting layer of the corresponding color. In other words, each of the red light emitting element 20Rc, the green light emitting element 20Gc, and the blue light emitting element 20Bc may be a bottom-emission type light emitting element. When each of the red light-emitting element 20Rc, the green light-emitting element 20Gc, and the blue light-emitting element 20Bc is a bottom-emission type light-emitting element, a first capping layer 14a is provided below the semi-reflective first electrode 12a so as to overlap with the semi-reflective first electrode 12a in a planar view, and a second capping layer 14b is provided below the semi-reflective second electrode 12b so as to overlap with the semi-reflective second electrode 12b in a planar view, and the refractive index of the first capping layer 14a is different from the refractive index of the second capping layer 14b.

[0062] As shown in Figure 11, in each of the red light-emitting element 20Rc, green light-emitting element 20Gc, and blue light-emitting element 20Bc provided in the display device 1c, it is preferable that the step between the light-emitting side surface of the first capping layer 14a and the light-emitting side surface of the second capping layer 14b is smaller than the step between the light-emitting side surface of the semi-reflective first electrode 12a and the light-emitting side surface of the semi-reflective second electrode 12b.

[0063] As shown in Figure 11, in each of the red light-emitting element 20Rc, green light-emitting element 20Gc, and blue light-emitting element 20Bc provided in the display device 1c, it is preferable that the refractive index of the first capping layer 14a is lower than the refractive index of the second capping layer 14b.

[0064] As shown in Figure 11, in each of the red light-emitting element 20Rc, green light-emitting element 20Gc, and blue light-emitting element 20Bc provided in the display device 1c, the refractive index of the first capping layer 14a is preferably 1.0 or more and less than 1.7, and the refractive index of the second capping layer 14b is preferably 1.7 or more and 2.2 or less.

[0065] As shown in Figure 12, in each of the red light-emitting element 20Rc, green light-emitting element 20Gc, and blue light-emitting element 20Bc provided in the display device 1c, the light-emitting efficiency of the part driven by the first electrode 12a and the part driven by the second electrode 12b was approximately at the same level, despite the film thickness of the first electrode 12a and the film thickness of the second electrode 12b being different.

[0066] 13, when the viewing angle characteristics of a pixel including a red light-emitting element 20Rc, a green light-emitting element 20Gc, and a blue light-emitting element 20Bc driven in a wide viewing-angle mode under white light emission conditions are compared with those of a pixel driven in a narrow viewing-angle mode, a wide viewing-angle characteristic is obtained in the wide viewing-angle mode driven by the first electrode 12a, and a high luminance is obtained in the front direction in the narrow viewing-angle mode driven by the second electrode 12b. Furthermore, in the narrow viewing-angle mode driven by the second electrode 12b, by providing the second capping layer 14b having a refractive index of 2.0, a higher luminance is obtained in an even narrower front direction than in the display devices 1, 1a, and 1b of embodiment 1, which do not have the second capping layer 14b having a refractive index of 2.0.

[0067] [Embodiment 3] Fig. 14 is a cross-sectional view showing a schematic configuration of a display device 1d of Embodiment 3. Fig. 15 is a diagram comparing the luminous efficiency of a portion driven by the first electrode 12a and a portion driven by the second electrode 12b in each of the red light-emitting element 20Rd, the green light-emitting element 20Gd, and the blue light-emitting element 20Bd provided in the display device 1d of Embodiment 3. Fig. 16 is a diagram showing that the viewing angle characteristics when the display device 1d of Embodiment 3, which includes a low-refractive-index first capping layer 14c on the first electrode 12a, is driven in the wide-viewing-angle mode are improved compared to the viewing angle characteristics when the display devices 1, 1a, and 1b of Embodiment 1, which do not include a low-refractive-index first capping layer 14c on the first electrode 12a, are driven in the wide-viewing-angle mode.

[0068] 14 , in each of red light-emitting element 20Rd, green light-emitting element 20Gd, and blue light-emitting element 20Bd provided in display device 1d, first capping layer 14c is provided on semi-reflective first electrode 12a so as to overlap with semi-reflective first electrode 12a in a planar view, and second capping layer 14b is provided on semi-reflective second electrode 12b so as to overlap with semi-reflective second electrode 12b in a planar view, and the refractive index of first capping layer 14a and the refractive index of second capping layer 14b are different. In this embodiment, a case where first capping layer 14c is formed using a material with a refractive index of 1.35 and second capping layer 14b is formed using a material with a refractive index of 2.0 will be described as an example, but the present invention is not limited to this.

[0069] As shown in Figure 14, in each of the red light-emitting element 20Rd, green light-emitting element 20Gd, and blue light-emitting element 20Bd provided in the display device 1d, a film 15 made of lithium fluoride is formed on each of the first capping layer 14c and second capping layer 14b.

[0070] As shown in Figure 15, in each of the red light-emitting element 20Rd, green light-emitting element 20Gd, and blue light-emitting element 20Bd provided in the display device 1d, the light-emitting efficiency of the part driven by the first electrode 12a and the part driven by the second electrode 12b was approximately at the same level, despite the film thickness of the first electrode 12a and the film thickness of the second electrode 12b being different.

[0071] 16, when the viewing angle characteristics of a pixel including a red light-emitting element 20Rd, a green light-emitting element 20Gd, and a blue light-emitting element 20Bd driven in a wide-viewing-angle mode under white light emission conditions are compared with those of a pixel driven in a narrow-viewing-angle mode, a wide viewing-angle characteristic is obtained in the wide-viewing-angle mode driven by the first electrode 12a, and a high luminance is obtained in the narrow-viewing-angle mode driven by the second electrode 12b. Furthermore, in the wide-viewing-angle mode driven by the first electrode 12a, by providing the first capping layer 14c having a refractive index of 1.35, an even wider viewing angle characteristic is obtained compared with the display devices 1, 1a, and 1b of embodiment 1 which do not have the first capping layer 14c having a refractive index of 1.35.

[0072] Fourth Embodiment FIG. 17 is a cross-sectional view showing a schematic configuration of a display device 1e according to a fourth embodiment.

[0073] In each of the red light emitting element 20Re, the green light emitting element 20Ge, and the blue light emitting element 20Be provided in the display device 1e shown in FIG. 17, a film 15a made of lithium fluoride is formed only on the first capping layer 14c.

[0074] Although not shown, when comparing the viewing angle characteristics when driven in a wide viewing angle mode and a narrow viewing angle mode under white light emission conditions in a pixel including a red light-emitting element 20Re, a green light-emitting element 20Ge, and a blue light-emitting element 20Be, a wide viewing angle characteristic was obtained in the wide viewing angle mode driven by the first electrode 12a, and a high luminance was obtained in the front direction in the narrow viewing angle mode driven by the second electrode 12b. Furthermore, in the narrow viewing angle mode driven by the second electrode 12b, by providing the film 15a made of lithium fluoride only on the first capping layer 14c, a higher luminance was obtained in an even narrower front direction compared to when the film 15 made of lithium fluoride was provided on both the first capping layer 14c and the second capping layer 14b.

[0075] [Embodiment 5] Fig. 18 is a cross-sectional view showing a schematic configuration of a display device 1f of embodiment 5. Fig. 19 is a diagram comparing the luminous efficiency of a portion driven by a first electrode 12a and a portion driven by a second electrode 12b in each of a tandem red light emitting element 20Rf, a tandem green light emitting element 20Gf, and a tandem blue light emitting element 20Bf provided in the display device 1f of embodiment 5. Fig. 20 is a diagram comparing the viewing angle characteristics when the display device 1f of embodiment 5 is driven in a wide viewing angle mode and a narrow viewing angle mode.

[0076] As shown in Figure 18, in each of the tandem red light-emitting element 20Rf, tandem green light-emitting element 20Gf, and tandem blue light-emitting element 20Bf provided in the display device 1f, a second light-emitting layer that emits light of the same color as the light-emitting layer of the corresponding color is provided between the semi-reflective first electrode 12a and the semi-reflective second electrode 12b, respectively, and the reflective third electrodes 3R, 3G, and 3B, so as to overlap with the light-emitting layer of the corresponding color in a planar view.

[0077] The functional layer 19Rb including a red light-emitting layer shown in FIG. 18 differs from the functional layer 19R including the red light-emitting layer 8R shown in FIG. 1 in that it includes a hole generation layer 17 instead of the first charge injection layer 5, which is a hole injection layer included in the functional layer 19R including the red light-emitting layer 8R shown in FIG. 1 . The hole generation layer 17 can be formed, for example, using a triphenylamine-based compound and an electron-accepting material. The functional layer 19Ra including a red light-emitting layer shown in FIG. 18 differs from the functional layer 19R including the red light-emitting layer 8R shown in FIG. 1 in that it includes an electron generation layer 16 instead of the second charge injection layer 11, which is an electron injection layer included in the functional layer 19R including the red light-emitting layer 8R shown in FIG. 1 . The electron generation layer 16 can be formed, for example, using an oxadiazole-based compound and Yb.

[0078] The functional layer 19Gb including a green light-emitting layer shown in FIG. 18 differs from the functional layer 19G including the green light-emitting layer 8G shown in FIG. 1 in that it includes a hole generation layer 17 instead of the first charge injection layer 5, which is a hole injection layer, included in the functional layer 19G including the green light-emitting layer 8G shown in FIG. 1 . The hole generation layer 17 can be formed, for example, using a triphenylamine-based compound and an electron-accepting material. The functional layer 19Ga including a green light-emitting layer shown in FIG. 18 differs from the functional layer 19G including the green light-emitting layer 8G shown in FIG. 1 in that it includes an electron generation layer 16 instead of the second charge injection layer 11, which is an electron injection layer, included in the functional layer 19G including the green light-emitting layer 8G shown in FIG. 1 . The electron generation layer 16 can be formed, for example, using an oxadiazole-based compound and Yb.

[0079] The functional layer 19Bb including a blue light-emitting layer shown in FIG. 18 differs from the functional layer 19B including the blue light-emitting layer 8B shown in FIG. 1 in that it includes a hole generation layer 17 instead of the first charge injection layer 5, which is a hole injection layer, included in the functional layer 19B including the blue light-emitting layer 8B shown in FIG. 1 . The hole generation layer 17 can be formed using, for example, a triphenylamine-based compound and an electron-accepting material. The functional layer 19Ba including a blue light-emitting layer shown in FIG. 18 differs from the functional layer 19B including the blue light-emitting layer 8B shown in FIG. 1 in that it includes an electron generation layer 16 instead of the second charge injection layer 11, which is an electron injection layer, included in the functional layer 19B including the blue light-emitting layer 8B shown in FIG. 1 . The electron generation layer 16 can be formed using, for example, an oxadiazole-based compound and Yb.

[0080] In this embodiment, the semi-reflective first electrode 12a and the semi-reflective second electrode 12b are each cathodes, and the reflective third electrodes 3R, 3G, and 3B are anodes, so the red light-emitting layer (second light-emitting layer) contained in functional layer 19Ra, the green light-emitting layer (second light-emitting layer) contained in functional layer 19Ga, and the blue light-emitting layer (second light-emitting layer) contained in functional layer 19Ba are each located closer to the reflective third electrodes 3R, 3G, and 3B than the red light-emitting layer (first light-emitting layer) contained in functional layer 19Rb, the green light-emitting layer (first light-emitting layer) contained in functional layer 19Gb, and the blue light-emitting layer (first light-emitting layer) contained in functional layer 19Bb, respectively. A hole generation layer 17 and an electron generation layer 16 are provided between each of the red light-emitting layer (first light-emitting layer), green light-emitting layer (first light-emitting layer), and blue light-emitting layer (first light-emitting layer) and each of the red light-emitting layer (second light-emitting layer), green light-emitting layer (second light-emitting layer), and blue light-emitting layer (second light-emitting layer), respectively. The electron generation layer 16 is provided closer to each of the red light-emitting layer (second light-emitting layer), green light-emitting layer (second light-emitting layer), and blue light-emitting layer (second light-emitting layer) than the hole generation layer 17.

[0081] On the other hand, although not shown, when the semi-reflective first electrode 12a and the semi-reflective second electrode 12b are each an anode and the reflective third electrodes 3R, 3G, and 3B are each a cathode, the red light-emitting layer (second light-emitting layer) contained in the functional layer 19Ra, the green light-emitting layer (second light-emitting layer) contained in the functional layer 19Ga, and the blue light-emitting layer (second light-emitting layer) contained in the functional layer 19Ba are each provided closer to the reflective third electrodes 3R, 3G, and 3B than the red light-emitting layer (first light-emitting layer) contained in the functional layer 19Rb, the green light-emitting layer (first light-emitting layer) contained in the functional layer 19Gb, and the blue light-emitting layer (first light-emitting layer) contained in the functional layer 19Bb, respectively. A hole generation layer 17 and an electron generation layer 16 are provided between each of the red light-emitting layer (first light-emitting layer), green light-emitting layer (first light-emitting layer), and blue light-emitting layer (first light-emitting layer) and each of the red light-emitting layer (second light-emitting layer), green light-emitting layer (second light-emitting layer), and blue light-emitting layer (second light-emitting layer), respectively. The hole generation layer 17 is provided closer to each of the red light-emitting layer (second light-emitting layer), green light-emitting layer (second light-emitting layer), and blue light-emitting layer (second light-emitting layer) than the electron generation layer 16.

[0082] In a light-emitting device configured to switch viewing angle modes by switching the drive electrode from one of the semi-reflective first electrode 12a to the other of the semi-reflective second electrode 12b, the relative luminance in each viewing angle mode is approximately half that of a typical light-emitting device not configured to switch viewing angle modes. On the other hand, in the tandem-type light-emitting device used in this embodiment, when two stacked light-emitting layers are used, the luminance is, in principle, twice that of a single-type light-emitting device having one light-emitting layer, and when three or more stacked light-emitting layers are used, the luminance is, in principle, more than twice that of a single-type light-emitting device having one light-emitting layer. Therefore, it is preferable to use a tandem-type light-emitting device as a light-emitting device configured to switch viewing angle modes. With this configuration, the viewing angle can be switched without a decrease in luminance compared to conventional displays using single-type light-emitting elements. The number of stacked light-emitting layers in a tandem-type light-emitting device is preferably two or more and five or less for each light-emitting element of each color. As described above, in the case of a single-type light-emitting element having a single light-emitting layer, the relative luminance is roughly halved when a two-stage switching mode between a wide viewing angle mode and a narrow viewing angle mode is introduced. Therefore, it is preferable to use a tandem-type light-emitting element having two or more stacked light-emitting layers. On the other hand, when the number of stacked light-emitting layers is six or more, the fabrication of the light-emitting element becomes complicated, and the negative impact of the additional manufacturing process outweighs the benefit of improved luminance, resulting in reduced productivity. The number of light-emitting layers in the light-emitting element of each color may be different for each light-emitting element. For example, the number of light-emitting layers in a blue light-emitting element having low luminous efficiency may be greater than the number of light-emitting layers in a green light-emitting element or the number of light-emitting layers in a red light-emitting element. Furthermore, for example, only the blue light-emitting element having low luminous efficiency may be configured as a tandem-type light-emitting element, while the green and red light-emitting elements may be configured as single-type light-emitting elements.

[0083] 19, in each of the red light emitting element 20Rf, the green light emitting element 20Gf, and the blue light emitting element 20Bf provided in the display device 1f, the light emitting efficiency of the portion driven by the first electrode 12a and the portion driven by the second electrode 12b was at approximately the same level, despite the difference in film thickness between the first electrode 12a and the second electrode 12b. Furthermore, compared to the case of the non-tandem type light emitting element described above, the light emitting efficiency of each color was improved by approximately 1.7 times or more.

[0084] As shown in Figure 20, when comparing the viewing angle characteristics when driven in wide viewing angle mode and narrow viewing angle mode under white light emission conditions in a pixel including red light-emitting element 20Rf, green light-emitting element 20Gf, and blue light-emitting element 20Bf, a wide viewing angle characteristic was obtained in the wide viewing angle mode driven by first electrode 12a, and a high brightness was obtained in the front direction in the narrow viewing angle mode driven by second electrode 12b.

[0085] [Additional Notes] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0086] The present disclosure can be used in a light-emitting element, a light-emitting device, a display device, and a method for driving a light-emitting element.

[0087] DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c, 1d, 1e, 1f Display device 2 Substrate 3R, 3G, 3B Reflective third electrode 3Rs, 3Gs, 3Bs Surface of reflective third electrode facing light-emitting layer 4 Edge cover 5 First charge injection layer 6 First charge transport layer 7R, 7G, 7B Second charge blocking layer 8R Red light-emitting layer 8G Green light-emitting layer 8B Blue light-emitting layer 9 First charge blocking layer 10 Second charge transport layer 11 Second charge injection layer 12a Semi-reflective first electrode (semi-reflective first common electrode) 12as Surface of semi-reflective first electrode facing light-emitting layer 12b Semi-reflective second electrode (semi-reflective second common electrode) 12bs Surface of semi-reflective second electrode facing light-emitting layer 13 Sealing layer 14a, 14c First capping layer 14b Second capping layer 15, 15a Films made of lithium fluoride 16 Electron generation layer 17 Hole generation layer 19R, 19Ra, 19Rb Functional layer including a red light-emitting layer 19G, 19Ga, 19Gb Functional layer including a green light-emitting layer 19B, 19Ba, 19Bb Functional layer including a blue light-emitting layer 20R, 20Ra to 20Rf Red light-emitting element 20G, 20Ga to 20Gf Green light-emitting element 20B, 20Ba to 20Bf Blue light-emitting element ML Non-light-emitting portion D1R, D1G, D1B First distance D2R, D2G, D2B Second distance

Claims

1. A light-emitting device comprising: a semi-reflective first electrode and a semi-reflective second electrode that is thicker than the semi-reflective first electrode; a reflective third electrode that is located in a layer separate from the semi-reflective first electrode and the semi-reflective second electrode; and a first light-emitting layer that is provided between the semi-reflective first electrode and the semi-reflective second electrode and the reflective third electrode, respectively, wherein the semi-reflective first electrode overlaps with a portion of the first light-emitting layer and a portion of the reflective third electrode in a planar view; and the semi-reflective second electrode overlaps with another portion of the first light-emitting layer and another portion of the reflective third electrode in a planar view.

2. The light-emitting element according to claim 1, wherein the semi-reflective first electrode and the semi-reflective second electrode are each provided above the first light-emitting layer, and the reflective third electrode is provided below the first light-emitting layer.

3. The light-emitting element described in claim 2, wherein a first capping layer is provided on the semi-reflective first electrode so as to overlap with the semi-reflective first electrode in a planar view, and a second capping layer is provided on the semi-reflective second electrode so as to overlap with the semi-reflective second electrode in a planar view, and the refractive index of the first capping layer is different from the refractive index of the second capping layer.

4. The light-emitting element according to claim 3, wherein a film made of lithium fluoride is formed on each of the first capping layer and the second capping layer.

5. The light-emitting element according to claim 3, wherein a film made of lithium fluoride is formed only on said first capping layer.

6. The light-emitting element according to claim 1, wherein the reflective third electrode is provided above the first light-emitting layer, and the semi-reflective first electrode and the semi-reflective second electrode are each provided below the first light-emitting layer.

7. The light-emitting element described in claim 6, wherein a first capping layer is provided below the semi-reflective first electrode so as to overlap with the semi-reflective first electrode in a planar view, and a second capping layer is provided below the semi-reflective second electrode so as to overlap with the semi-reflective second electrode in a planar view, and the refractive index of the first capping layer is different from the refractive index of the second capping layer.

8. A light-emitting element described in any one of claims 3, 4, 5, and 7, wherein the step between the light-emitting surface of the first capping layer and the light-emitting surface of the second capping layer is smaller than the step between the light-emitting surface of the semi-reflective first electrode and the light-emitting surface of the semi-reflective second electrode.

9. The light-emitting device according to any one of claims 3, 4, 5, 7 and 8, wherein the refractive index of the first capping layer is lower than the refractive index of the second capping layer.

10. The light-emitting device according to any one of claims 3, 4, 5, 7, 8 and 9, wherein the refractive index of the first capping layer is 1.0 or more and less than 1.

7.

11. The light-emitting device according to any one of claims 3, 4, 5, 7, 8, 9 and 10, wherein the refractive index of the second capping layer is 1.7 or more and 2.2 or less.

12. A light-emitting element described in any one of claims 1 to 11, wherein, when an area where the semi-reflective first electrode, the reflective third electrode, and the first light-emitting layer overlap in a planar view is defined as a first area, and an area where the semi-reflective second electrode, the reflective third electrode, and the first light-emitting layer overlap in a planar view is defined as a second area, the value of ((first area) / (first area+second area)) x 100(%) is 10% or more and 90% or less.

13. A light-emitting element described in any one of claims 1 to 12, wherein a functional layer including the first light-emitting layer is provided between each of the semi-reflective first electrode and the semi-reflective second electrode and the reflective third electrode, and a microcavity structure is formed by each of the semi-reflective first electrode and the semi-reflective second electrode, the functional layer including the first light-emitting layer, and the reflective third electrode.

14. A light-emitting element described in any one of claims 1 to 13, wherein a second light-emitting layer that emits light of the same color as the first light-emitting layer is provided between each of the semi-reflective first electrode and the semi-reflective second electrode and the reflective third electrode, so as to overlap with the first light-emitting layer in a planar view.

15. The light-emitting element described in claim 14, wherein each of the semi-reflective first electrode and the semi-reflective second electrode is a cathode, the reflective third electrode is an anode, the second light-emitting layer is disposed closer to the reflective third electrode than the first light-emitting layer, a hole generation layer and an electron generation layer are disposed between the first light-emitting layer and the second light-emitting layer, and the electron generation layer is disposed closer to the second light-emitting layer than the hole generation layer.

16. A light-emitting element according to any one of claims 1 to 15, wherein the semi-reflective first electrode and the semi-reflective second electrode are each formed from a material selected from the group consisting of a mixture of magnesium and silver, a mixture of magnesium and aluminum, and aluminum.

17. The light-emitting element of claim 14, wherein the semi-reflective first electrode and the semi-reflective second electrode are each an anode, the reflective third electrode is a cathode, the second light-emitting layer is disposed closer to the reflective third electrode than the first light-emitting layer, a hole generation layer and an electron generation layer are disposed between the first light-emitting layer and the second light-emitting layer, and the hole generation layer is disposed closer to the second light-emitting layer than the electron generation layer.

18. A light-emitting element described in any one of claims 1 to 17, wherein the first light-emitting layer is composed of a single island-shaped light-emitting layer, a portion of the single island-shaped light-emitting layer overlaps with the semi-reflective first electrode in a planar view, and another portion of the single island-shaped light-emitting layer overlaps with the semi-reflective second electrode in a planar view.

19. A light-emitting element described in any one of claims 1 to 17, wherein the first light-emitting layer is composed of two island-shaped light-emitting layers, one of the two island-shaped light-emitting layers overlapping the semi-reflective first electrode in a planar view, and the other of the two island-shaped light-emitting layers overlapping the semi-reflective second electrode in a planar view.

20. A light emitting device comprising a plurality of light emitting elements according to any one of claims 1 to 19.

21. A light emitting device comprising one or more light emitting elements according to any one of claims 14, 15 and 17.

22. A light-emitting device comprising a plurality of light-emitting elements according to claim 18, wherein the plurality of light-emitting elements include a red light-emitting element, a green light-emitting element, and a blue light-emitting element, wherein the red light-emitting element includes a red light-emitting layer as the first light-emitting layer, the green light-emitting element includes a green light-emitting layer as the first light-emitting layer, and the blue light-emitting element includes a blue light-emitting layer as the first light-emitting layer, a plurality of pixels each including the red light-emitting element, the green light-emitting element, and the blue light-emitting element are provided along a first direction and a second direction perpendicular to the first direction, wherein the semi-reflective first electrode of the red light-emitting element, the semi-reflective first electrode of the green light-emitting element, and the semi-reflective first electrode of the blue light-emitting element in each of the plurality of pixels are provided as a semi-reflective common first electrode, and the semi-reflective second electrode of the red light-emitting element, the semi-reflective second electrode of the green light-emitting element, and the semi-reflective second electrode of the blue light-emitting element in each of the plurality of pixels are provided as a semi-reflective common second electrode, a display device, wherein the semi-reflective common first electrodes and the semi-reflective common second electrodes are alternately provided in both the first direction and the second direction in a plan view; 23. A display device as described in claim 22, wherein the three pixels adjacent in the second direction are a first pixel, a second pixel, and a third pixel, arranged in this order along the second direction, the semi-reflective common first electrode included in the second pixel is connected to the semi-reflective common first electrode included in one of the first pixel and the third pixel, and the semi-reflective common second electrode included in the second pixel is connected to the semi-reflective common second electrode included in the other of the first pixel and the third pixel.

24. A light-emitting device comprising a plurality of light-emitting elements according to claim 19, wherein the plurality of light-emitting elements include a red light-emitting element, a green light-emitting element, and a blue light-emitting element, wherein the red light-emitting element includes a red light-emitting layer as the first light-emitting layer, the green light-emitting element includes a green light-emitting layer as the first light-emitting layer, and the blue light-emitting element includes a blue light-emitting layer as the first light-emitting layer, wherein the semi-reflective first electrode of each of the plurality of red light-emitting elements, the semi-reflective first electrode of each of the plurality of green light-emitting elements, and the semi-reflective first electrode of each of the plurality of blue light-emitting elements, which are provided along a first direction, are provided as a semi-reflective common first electrode extending in the first direction, and the semi-reflective second electrode of each of the plurality of red light-emitting elements, the semi-reflective second electrode of each of the plurality of green light-emitting elements, and the semi-reflective second electrode of each of the plurality of blue light-emitting elements, which are provided along the first direction, are provided as a semi-reflective common second electrode extending in the first direction, In a plan view, the semi-reflective common first electrodes and the semi-reflective common second electrodes are alternately provided in a second direction intersecting the first direction.

25. A method for driving a light-emitting device comprising: a semi-reflective first electrode; a semi-reflective second electrode that is thicker than the semi-reflective first electrode; a reflective third electrode that is located in a layer separate from the semi-reflective first electrode and the semi-reflective second electrode; and a first light-emitting layer that is provided between the semi-reflective first electrode, the semi-reflective second electrode, and the reflective third electrode, respectively; the method including: a wide viewing angle mode that causes only a first region where the semi-reflective first electrode, a portion of the first light-emitting layer, and a portion of the reflective third electrode overlap in a planar view to emit light; and a narrow viewing angle mode that causes only a second region where the semi-reflective second electrode, another portion of the first light-emitting layer, and another portion of the reflective third electrode overlap in a planar view to emit light.

26. The method of driving a light-emitting device according to claim 25, further comprising a general mode in which the first region and the second region are simultaneously illuminated.

Images