Display device

Abstract

To provide a display device in which the fourth color sub-pixel is formed without adding a step, a mask, a material, and a circuit construction or the like.SOLUTION: A display device includes first to third light emission devices. The first light emission device includes: a first positive electrode; a first negative electrode; and a first light emission layer between the first positive electrode and the first negative electrode. The second light emission device includes: a second positive electrode; a second negative electrode; and a second light emission layer between the second positive electrode and the second negative electrode. The third light emission device includes: a third positive electrode; a third negative electrode; and a third light emission layer and a fourth light emission layer that are between the third positive electrode and the third negative electrode. The fourth light emission layer is positioned between the third light emission layer and the third negative electrode, and is contacted to the third light emission layer. Each light emission of the first, second, and third light emission devices are different in a color, respectively. The first and third light emission layers include a first light emission material. The second and fourth light emission layers include a second light emission material. The first and second light emission materials have different peak wavelengths of a light emission spectrum from each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention relates to a display device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification etc. relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, a driving method thereof, or a manufacturing method thereof. [Background technology]

[0002] Light-emitting devices (organic EL devices) that utilize electroluminescence (EL) using organic compounds are becoming more and more practical. The basic structure of these light-emitting devices is a pair of electrodes sandwiching an organic compound layer (EL layer) containing a light-emitting material between them. By applying a voltage to this device, carriers are injected, and the recombination energy of the carriers is utilized to emit light from the light-emitting material.

[0003] Since such light-emitting devices are self-luminous, when used as display pixels, they have advantages such as high visibility and no need for backlighting compared to liquid crystals, making them suitable for use in flat panel displays. Another major advantage of displays using such light-emitting devices is that they can be made thin and lightweight. Another characteristic is that they have an extremely fast response speed.

[0004] In addition, in a display using an organic EL device, in order to improve color expression, in addition to the three sub-pixels of red, green, and blue, a fourth color sub-pixel such as yellow may be required. One example of a method for realizing such a display is a method of forming a fourth color sub-pixel using a light-emitting device having a light-emitting substance that emits yellow light. Patent Document 1 discloses a light-emitting substance that emits yellow light and a light-emitting device using the substance.

[0005] Another example of a method for realizing such a display is to fabricate a single-type light-emitting device that emits red, green, and blue light, and a tandem-type light-emitting device made of a material common to the single-type light-emitting device, on the same substrate, and to form a fourth color subpixel using the tandem-type light-emitting device. Patent Document 2 discloses a display configuration in which a single-type light-emitting device and a tandem-type light-emitting device are provided on the same substrate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-214726 A [Patent Document 2] US Patent Application Publication No. 2016 / 0155378 Summary of the Invention [Problem to be solved by the invention]

[0007] If a fourth color subpixel is required, fabrication methods for producing an emissive device using a fourth color emissive material or layer may require additional steps, masks and materials, which can increase manufacturing costs.

[0008] Even in a method of fabricating both a single-type light-emitting device and a tandem-type light-emitting device on the same substrate, the tandem-type light-emitting device requires additional steps and materials, such as an intermediate layer (charge generating layer). Furthermore, in a display with such a configuration, the voltage applied must be different between the single-type light-emitting device and the tandem-type light-emitting device, which requires an additional circuit configuration, and this may also increase the manufacturing cost.

[0009] Therefore, an object of one embodiment of the present invention is to provide a display device in which a fourth color subpixel is formed without adding any process, mask, material, circuit configuration, or the like. Another object of one embodiment of the present invention is to provide a display device with reduced manufacturing costs. Another object of one embodiment of the present invention is to provide an inexpensive display device. Another object of one embodiment of the present invention is to provide a novel display device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract problems other than these from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0011] One embodiment of the present invention includes first to third light-emitting devices. The first light-emitting device has a first anode, a first cathode, and a first light-emitting layer between the first anode and the first cathode. The second light-emitting device has a second anode, a second cathode, and a second light-emitting layer between the second anode and the second cathode. The third light-emitting device has a third anode, a third cathode, and a third light-emitting layer and a fourth light-emitting layer between the third anode and the third cathode. the layer is located between a third light-emitting layer and a third cathode and in contact with the third light-emitting layer, the light emission of the first light-emitting device, the light emission of the second light-emitting device, and the light emission of the third light-emitting device are different in color from one another, the first light-emitting layer and the third light-emitting layer contain a first light-emitting material, the second light-emitting layer and the fourth light-emitting layer contain a second light-emitting material, and the first light-emitting material and the second light-emitting material have emission spectra with peak wavelengths different from one another.

[0012] Another embodiment of the present invention includes first to third light-emitting devices. The first light-emitting device has a first anode, a first cathode, and a first light-emitting layer between the first anode and the first cathode. The second light-emitting device has a second anode, a second cathode, and a second light-emitting layer between the second anode and the second cathode. The third light-emitting device has a third anode, a third cathode, and a third light-emitting layer and a fourth light-emitting layer between the third anode and the third cathode. a fourth light-emitting layer is located between the third light-emitting layer and a third cathode and in contact with the third light-emitting layer; the first light-emitting layer and the third light-emitting layer have a first light-emitting material; the second light-emitting layer and the fourth light-emitting layer have a second light-emitting material; the first light-emitting device does not have the second light-emitting material; the second light-emitting device does not have the first light-emitting material; and the first light-emitting material and the second light-emitting material have emission spectra with peak wavelengths different from each other.

[0013] In the display device having each of the above configurations, it is more preferable that the peak wavelength of the emission spectrum of the first light-emitting substance is longer than the peak wavelength of the emission spectrum of the second light-emitting substance, and the thickness of the third light-emitting layer is thinner than the thickness of the fourth light-emitting layer.

[0014] In the display device having each of the above configurations, it is more preferable that the peak wavelength of the emission spectrum of the first light-emitting substance is longer than the peak wavelength of the emission spectrum of the second light-emitting substance, and that the first light-emitting layer and the third light-emitting layer each contain a hole-transporting material. It is also preferable that the first light-emitting layer has a higher hole-transporting property than the second light-emitting layer. It is also preferable that the third light-emitting layer has a higher hole-transporting property than the fourth light-emitting layer. It is also more preferable that the first light-emitting device has a hole-blocking layer between the first light-emitting layer and the first cathode.

[0015] Another embodiment of the present invention is a display device having any of the above structures, which includes a fourth light-emitting device. The fourth light-emitting device has a fourth anode, a fourth cathode, and a fifth light-emitting layer between the fourth anode and the fourth cathode. The third light-emitting device has a sixth light-emitting layer between the third anode and the third cathode. The sixth light-emitting layer is located between the fourth light-emitting layer and the third cathode and in contact with the fourth light-emitting layer. The fifth light-emitting layer and the sixth light-emitting layer include a third light-emitting substance, and the third light-emitting substance has an emission spectrum with a peak wavelength different from that of the first light-emitting substance and the second light-emitting substance.

[0016] Another embodiment of the present invention includes first to third light-emitting devices. The first light-emitting device has a first anode, a first cathode, and a first light-emitting layer and a first hole blocking layer between the first anode and the first cathode. The first hole blocking layer is positioned between the first light-emitting layer and the first cathode. The second light-emitting device has a second anode, a second cathode, and a second light-emitting layer between the second anode and the second cathode. The third light-emitting device has a third anode, a third cathode, and a first hole blocking layer between the third anode and the third cathode. the fourth light-emitting layer is located between the third light-emitting layer and a third cathode, the light emission of the first light-emitting device, the light emission of the second light-emitting device, and the light emission of the third light-emitting device are different in color from each other, the first light-emitting layer and the third light-emitting layer have a first light-emitting substance and a hole-transporting material, the second light-emitting layer and the fourth light-emitting layer have a second light-emitting substance, and the first light-emitting substance and the second light-emitting substance have different peak wavelengths in their emission spectra from each other.

[0017] In the display device having each of the above configurations, the third light-emitting device may have a second hole-blocking layer located between the third light-emitting layer and the fourth light-emitting layer. In the display device having each of the above configurations, the first light-emitting layer preferably has a higher hole-transporting property than the second light-emitting layer. The third light-emitting layer preferably has a higher hole-transporting property than the fourth light-emitting layer.

[0018] Another embodiment of the present invention includes first to third light-emitting devices. The first light-emitting device has a first anode, a first cathode, and a first light-emitting layer between the first anode and the first cathode, a second light-emitting layer, and a first intermediate layer. The first intermediate layer is located between the first light-emitting layer and the second light-emitting layer. The second light-emitting device has a second anode, a second cathode, and a third light-emitting layer between the second anode and the second cathode, a fourth light-emitting layer, and a second intermediate layer. The second intermediate layer is located between the third light-emitting layer and the fourth light-emitting layer. The third light-emitting device has a third anode and a third a cathode, and a fifth light-emitting layer, a sixth light-emitting layer, and a third intermediate layer between a third anode and a third cathode, the third intermediate layer being located between the fifth light-emitting layer and the sixth light-emitting layer, the light emission of the first light-emitting device, and the light emission of the second light-emitting device being different in color from each other, the first light-emitting layer, the second light-emitting layer, and the fifth light-emitting layer comprising a first light-emitting material, the third light-emitting layer, the fourth light-emitting layer, and the sixth light-emitting layer comprising a second light-emitting material, and the first light-emitting material and the second light-emitting material having different peak wavelengths in their emission spectra from each other.

[0019] Another embodiment of the present invention includes first to third light-emitting devices. The first light-emitting device has a first anode, a first cathode, and a first light-emitting layer between the first anode and the first cathode, a second light-emitting layer, and a first intermediate layer. The first intermediate layer is located between the first light-emitting layer and the second light-emitting layer. The second light-emitting device has a second anode, a second cathode, and a third light-emitting layer between the second anode and the second cathode, a fourth light-emitting layer, and a second intermediate layer. The second intermediate layer is located between the third light-emitting layer and the fourth light-emitting layer. The third light-emitting device has a third anode and a third light-emitting layer. a third anode and a third cathode, a fifth light-emitting layer, a sixth light-emitting layer, and a third intermediate layer between the third anode and the third cathode, the third intermediate layer being located between the fifth light-emitting layer and the sixth light-emitting layer, the first light-emitting layer, the second light-emitting layer, and the fifth light-emitting layer having a first light-emitting material, the third light-emitting layer, the fourth light-emitting layer, and the sixth light-emitting layer having a second light-emitting material, the first light-emitting device does not have the second light-emitting material, the second light-emitting device does not have the first light-emitting material, and the first light-emitting material and the second light-emitting material have emission spectra with peak wavelengths different from each other.

[0020] In the display device having the above configuration, it is more preferable that the first intermediate layer, the second intermediate layer, and the third intermediate layer each contain an organic compound and an alkali metal or an alkaline earth metal.

[0021] In the display device having the above configuration, it is more preferable that the first intermediate layer, the second intermediate layer, and the third intermediate layer each contain the same organic compound and the same alkali metal or alkaline earth metal.

[0022] Another embodiment of the present invention is a display device having the above-described structure, the display device including a fourth light-emitting device, the fourth light-emitting device including a fourth anode, a fourth cathode, and a seventh light-emitting layer, an eighth light-emitting layer, and a fourth intermediate layer between the fourth anode and the fourth cathode, the fourth intermediate layer being positioned between the seventh light-emitting layer and the eighth light-emitting layer, the third light-emitting device including a ninth light-emitting layer between the third anode and the third cathode, the ninth light-emitting layer being in contact with the sixth light-emitting layer, the seventh light-emitting layer, the eighth light-emitting layer, and the ninth light-emitting layer including a third light-emitting substance, the third light-emitting substance having a peak wavelength of an emission spectrum different from those of the first light-emitting substance and the second light-emitting substance.

[0023] In the display device having the above configuration, it is more preferable that the first intermediate layer, the second intermediate layer, the third intermediate layer and the fourth intermediate layer each contain an organic compound and an alkali metal or an alkaline earth metal.

[0024] In the display device having the above configuration, it is more preferable that the first intermediate layer, the second intermediate layer, the third intermediate layer and the fourth intermediate layer each contain the same organic compound and the same alkali metal or alkaline earth metal. Effect of the Invention

[0025] According to one embodiment of the present invention, a display device in which a fourth color subpixel is formed can be provided without adding any process, mask, material, circuit configuration, or the like. According to another embodiment of the present invention, a display device with reduced manufacturing costs can be provided. According to another embodiment of the present invention, an inexpensive display device can be provided. According to another embodiment of the present invention, a novel display device can be provided.

[0026] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims. [Brief description of the drawings]

[0027] [Figure 1] FIG. 1A is a top view illustrating a structure of a display device according to an embodiment, and FIG. 1B is a cross-sectional view illustrating the structure of a display device according to an embodiment. [Diagram 2] 2A and 2B are cross-sectional views illustrating a structure of a display device according to an embodiment. [Diagram 3] 3A and 3B are cross-sectional views illustrating a structure of a display device according to an embodiment. [Figure 4] 4A and 4B are cross-sectional views illustrating a structure of a display device according to an embodiment. [Diagram 5] 5A and 5B are cross-sectional views illustrating a structure of a display device according to an embodiment. [Figure 6] FIG. 6 is a cross-sectional view illustrating a configuration of a display device according to an embodiment. [Figure 7] FIG. 7 is a cross-sectional view illustrating a configuration of a display device according to an embodiment. [Figure 8] 8A to 8C are cross-sectional views illustrating a structure of a display device according to an embodiment. [Figure 9] FIG. 9A is a top view illustrating a structure of a display device according to an embodiment, and FIG. 9B is a cross-sectional view illustrating a structure of a display device according to an embodiment. [Figure 10] 10A to 10D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 11] 11A to 11D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 12] 12A and 12B are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 13] 13(A) to 13(F) are diagrams illustrating a light-emitting device. [Figure 14] 14(A) and 14(B) are perspective views showing an example of a display device. [Figure 15] FIG. 15 is a cross-sectional view showing an example of a display device. [Figure 16]16A to 16D are diagrams illustrating examples of electronic devices. [Figure 17] 17A to 17F are diagrams illustrating examples of electronic devices. [Figure 18] 18A to 18G are diagrams illustrating examples of electronic devices. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and the form and details can be changed in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiment shown below.

[0029] In addition, for ease of understanding, the position, size, range, etc. of each component shown in the drawings, etc. may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0030] In addition, in this specification, ordinal numbers such as first, second, etc. are used for convenience and may not indicate the order of steps or stacking. Therefore, for example, "first" can be appropriately replaced with "second" or "third" to explain. In addition, the ordinal numbers described in this specification may not match the ordinal numbers used to specify one embodiment of the present invention.

[0031] In addition, in this specification and the like, when describing the configuration of the invention using drawings, the same reference numerals may be used in common between different drawings.

[0032] In addition, in this specification and the like, the term "film" and the term "layer" can be interchanged. For example, the term "conductive layer" may be changed to the term "conductive film." Or, for example, the term "insulating film" may be changed to the term "insulating layer."

[0033] (Embodiment 1) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0034] FIG 1A shows a top view of a display device 100 which is a display device of one embodiment of the present invention. The display device 100 includes a display portion in which a plurality of pixels 110 are arranged, and a connection portion 140 on the outer side of the display portion. A plurality of subpixels are arranged in a matrix in the display portion. FIG 1A shows two rows and eight columns of subpixels, which together form two rows and two columns of pixels 110. The connection portion 140 can also be called a cathode contact portion.

[0035] The top surface shape of the subpixel shown in Fig. 1(A) corresponds to the top surface shape of the light-emitting region. In this specification and the like, the top surface shape refers to a shape in a plan view, that is, a shape seen from above. Examples of the top surface shape of the subpixel include a triangle, a quadrangle (including a rectangle, a rhombus, and a square), a polygon such as a pentagon, a shape with rounded corners of these polygons, an ellipse, and a circle.

[0036] In addition, the circuit layout constituting the subpixel is not limited to the range of the subpixel shown in Fig. 1(A), and the components of the circuit may be located outside the range. For example, some or all of the transistors of the subpixel 50R shown in Fig. 1(A) may be located outside the range of the subpixel 50R. The transistors of the subpixel 50R may be located within the range of the subpixel 50R, the range of the subpixel 50G, the range of the subpixel 50B, or the range of the subpixel 50X shown in Fig. 1(A), or may be located across a plurality of these ranges.

[0037] 1A, the aperture ratios (sizes, which can also be referred to as sizes of light-emitting regions) of the sub-pixels 50R, 50G, 50B, and 50X are shown to be equal or approximately equal, but one embodiment of the present invention is not limited thereto. The aperture ratios of the sub-pixels 50R, 50G, 50B, and 50X can be determined as appropriate. The aperture ratios of the sub-pixels 50R, 50G, 50B, and 50X may be different from each other, or two or more of them may be equal or approximately equal.

[0038] A stripe arrangement is applied to the pixel 110 shown in Fig. 1(A). The pixel 110 shown in Fig. 1(A) is composed of four subpixels, namely, subpixel 50R, subpixel 50G, subpixel 50B, and subpixel 50X. The subpixels 50R, 50G, 50B, and 50X emit light of different colors. The subpixels 50R, 50G, and 50B may be red (R), green (G), and blue (B) subpixels. The subpixel 50X may be yellow (Y), cyan (C), magenta (M), and white (W) subpixels.

[0039] In this specification and the like, the row direction may be referred to as the X direction, the column direction as the Y direction, and the depth direction as the Z direction. Figure 1(A) shows an example in which sub-pixels of different colors are arranged side by side in the X direction, and sub-pixels of the same color are arranged side by side in the Y direction.

[0040] Fig. 1B shows a cross-sectional view taken along dashed line X1-X2 in Fig. 1A, and Figs. 2 to 9 show modified examples of the cross-sectional view taken along dashed line X1-X2 in Fig. 1A.

[0041] In the display device 100, a light emitting device 10R, a light emitting device 10G, a light emitting device 10B, and a light emitting device 10X are provided on a layer 121 including transistors (not shown), and a protective layer 122 is provided to cover these light emitting devices. A substrate 124 is further attached thereon by a resin layer 123. An insulating layer 125 is provided in the region between adjacent light emitting devices.

[0042] The display device according to one embodiment of the present invention is preferably a top emission display device that emits light in a direction opposite to a substrate on which a light-emitting device is formed.

[0043] The layer 121 may have a laminated structure in which, for example, a plurality of transistors (not shown) are provided on a substrate and an insulating layer is provided to cover these transistors. The layer 121 may have a recess between adjacent light emitting devices. For example, a recess may be provided in an insulating layer located on the outermost surface of the layer 121. A configuration example of the layer 121 will be described later in the fourth embodiment.

[0044] The light emitted by the light emitting device 10R, the light emitting device 10G, the light emitting device 10B, and the light emitting device 10X are different in color from one another. For example, it is preferable that the light emitting device 10R emits red (R) light, the light emitting device 10G emits green (G) light, and the light emitting device 10B emits blue (B) light. It is also preferable that the light emitting device 10X emits yellow (Y), cyan (C), magenta (M), or white (W) light.

[0045] As shown in FIG. 1(B), in the display device 100, an anode 11R, an anode 11G, an anode 11B, and an anode 11X are provided on the layer 121, a hole injection / transport layer 12 is provided on the anode 11R, the anode 11G, the anode 11B, and the anode 11X, a light-emitting layer 13R, a light-emitting layer 13G, a light-emitting layer 13B, and a light-emitting layer 13X_1 are provided on the hole injection / transport layer 12, a light-emitting layer 13X_2 is provided on the light-emitting layer 13R, a light-emitting layer 13G, a light-emitting layer 13B, and a light-emitting layer 13X_2, an electron injection / transport layer 14 is provided on the light-emitting layer 13R, a light-emitting layer 13G, a light-emitting layer 13B, and a light-emitting layer 13X_2, and a cathode 15 is formed on the electron injection / transport layer 14, thereby providing light-emitting devices 10R, 10G, 10B, and 10X. The hole injection / transport layer 12 preferably has a laminated structure, for example, a laminated structure in which a hole injection layer and a hole transport layer are laminated in this order from each anode side, and the electron injection / transport layer 14 preferably has a laminated structure, for example, a laminated structure in which an electron transport layer and an electron injection layer are laminated in this order from each light-emitting layer side.

[0046] The hole injection / transport layer 12, the electron injection / transport layer 14, and the cathode 15 are preferably layers shared by all the light-emitting devices (hereinafter, these layers may be referred to as common layers). The light-emitting layers 13R, 13G, 13B, 13X_1, and 13X_2 are preferably layers formed in each light-emitting device by a vacuum deposition method using a metal mask.

[0047] The light-emitting device 10R has a hole injection / transport layer 12, a light-emitting layer 13R, and an electron injection / transport layer 14 between an anode 11R and a cathode 15. The light-emitting layer 13R is located between the hole injection / transport layer 12 and the electron injection / transport layer 14. The light-emitting layer 13R also has at least a light-emitting substance R. As the light-emitting substance R, a light-emitting substance that emits red light can be used.

[0048] The light-emitting device 10G has a hole injection / transport layer 12, a light-emitting layer 13G, and an electron injection / transport layer 14 between an anode 11G and a cathode 15. The light-emitting layer 13G is located between the hole injection / transport layer 12 and the electron injection / transport layer 14. The light-emitting layer 13G also has at least a light-emitting substance G. As the light-emitting substance G, a light-emitting substance that emits green light can be used.

[0049] The light-emitting device 10B has a hole injection / transport layer 12, a light-emitting layer 13B, and an electron injection / transport layer 14 between an anode 11B and a cathode 15. The light-emitting layer 13B is located between the hole injection / transport layer 12 and the electron injection / transport layer 14. The light-emitting layer 13B also has at least a light-emitting substance B. As the light-emitting substance B, a light-emitting substance that emits blue light can be used.

[0050] In this specification, the blue wavelength region is a wavelength region of 400 nm or more and less than 490 nm, and blue emission is emission having at least one emission spectrum peak in this region. The green wavelength region is a wavelength region of 490 nm or more and less than 580 nm, and green emission is emission having at least one emission spectrum peak in this region. The red wavelength region is a wavelength region of 580 nm or more and less than 750 nm, and red emission is emission having at least one emission spectrum peak in this region.

[0051] Light-emitting device 10X has a hole injection / transport layer 12 between an anode 11X and a cathode 15, a light-emitting layer having a structure in which a plurality of light-emitting layers emitting different colors are in contact with each other and stacked (also referred to as a stacked light-emitting layer), and an electron injection / transport layer 14. Here, the number of stacked light-emitting layers constituting the stacked light-emitting layer of light-emitting device 10X is preferably 2 or 3. By stacking light-emitting layers with different emission colors, light-emitting device 10X can emit light of a different color from each of the light-emitting layers.

[0052] FIG. 1(B) shows an example in which the light-emitting device 10X has a stacked light-emitting layer structure composed of two light-emitting layers (13X_1, 13X_2). The light-emitting layer 13X_1 and the light-emitting layer 13X_2 are located between the hole injection / transport layer 12 and the electron injection / transport layer 14. The light-emitting layer 13X_2 is located between the light-emitting layer 13X_1 and the cathode 15, and is in contact with the light-emitting layer 13X_1. In other words, the light-emitting layer 13X_2 is in contact with the surface of the light-emitting layer 13X_1 on the cathode 15 side.

[0053] FIG. 3(A) shows an example in which the light-emitting device 10X has a stacked light-emitting layer composed of three light-emitting layers (13X_1, 13X_2, 13X_3). The light-emitting layer 13X_1, the light-emitting layer 13X_2, and the light-emitting layer 13X_3 are located between the hole injection / transport layer 12 and the electron injection / transport layer 14. The light-emitting layer 13X_2 is located between the light-emitting layer 13X_1 and the cathode 15, and is in contact with the light-emitting layer 13X_1. The light-emitting layer 13X_3 is located between the light-emitting layer 13X_2 and the cathode 15, and is in contact with the light-emitting layer 13X_2. In other words, the light-emitting layer 13X_2 is in contact with the surface of the light-emitting layer 13X_1 on the cathode 15 side, and the light-emitting layer 13X_3 is in contact with the surface of the light-emitting layer 13X_2 on the cathode 15 side.

[0054] Each of the light-emitting layers of the light-emitting device 10X is a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13R, the light-emitting layer 13G, or the light-emitting layer 13B. With this configuration, the light-emitting device 10X can be manufactured without adding any new process or material in order to provide the light-emitting device 10X to the display device 100, thereby reducing the cost of the display device 100.

[0055] In this specification, when it is stated that a certain light-emitting layer is a layer formed by a vacuum deposition method using a metal mask in the same process as light-emitting layer A, the light-emitting layer is a layer having the same light-emitting substance as light-emitting layer A. The light-emitting layer is also assumed to contain the same material as light-emitting layer A and to be composed of the same material. The film thickness of the light-emitting layer is also assumed to be the same as the film thickness of light-emitting layer A. In this specification, "similar" means that it may be different to an extent that allows for the film thickness precision of the film-forming device and fluctuations in composition. In this specification, "in the same process" can also be rephrased as "at the same time."

[0056] Hereinafter, for simplicity, a layer formed by vacuum deposition using a metal mask in the same process as light-emitting layer 13R may be referred to as a layer containing light-emitting material R. A layer formed by vacuum deposition using a metal mask in the same process as light-emitting layer 13G may be referred to as a layer containing light-emitting material G. A layer formed by vacuum deposition using a metal mask in the same process as light-emitting layer 13B may be referred to as a layer containing light-emitting material B.

[0057] 1(B), when the light-emitting device 10X has a stacked light-emitting layer structure composed of two light-emitting layers (13X_1, 13X_2), and when one of the two light-emitting layers is a layer containing a light-emitting material R and the other is a layer containing a light-emitting material G, the light-emitting device 10X can emit yellow (Y) light. Hereinafter, the light-emitting device 10X having this combination of light-emitting layers may be referred to as a yellow (Y) light-emitting device 10X.

[0058] 1(B), when the light-emitting device 10X has a stacked light-emitting layer structure composed of two light-emitting layers (13X_1, 13X_2), and when one of the two light-emitting layers is a layer containing a light-emitting material R and the other is a layer containing a light-emitting material B, the light-emitting device 10X can emit magenta (M) light. Hereinafter, the light-emitting device 10X having this combination of light-emitting layers may be referred to as a magenta (M) light-emitting device 10X.

[0059] 1(B), when the light-emitting device 10X has a stacked light-emitting layer structure composed of two light-emitting layers (13X_1, 13X_2), and when one of the two light-emitting layers is a layer containing a light-emitting material G and the other is a layer containing a light-emitting material B, the light-emitting device 10X can emit cyan (C) light. Hereinafter, the light-emitting device 10X having this combination of light-emitting layers may be referred to as a cyan (C) light-emitting device 10X.

[0060] 3(A), when the light-emitting device 10X has a stacked light-emitting layer structure composed of three light-emitting layers (13X_1, 13X_2, 13X_3), each of which is a layer having a light-emitting material R, a layer having a light-emitting material G, and a layer having a light-emitting material B, the light-emitting device 10X can emit white (W) light. Hereinafter, the light-emitting device 10X having this combination of light-emitting layers may be referred to as a white (W) light-emitting device 10X.

[0061] In a light-emitting device in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different emission colors are directly stacked, the emission intensity of the light-emitting layer L, which emits light of a long wavelength, may be stronger than the emission intensity of the light-emitting layer S, which emits light of a short wavelength. (In this case, the light-emitting substance x contained in the light-emitting layer L has a peak wavelength of its emission spectrum that is longer in wavelength than the light-emitting substance y contained in the light-emitting layer S.) The reason for this is that the light-emitting substance x has lower excitation energy and is easier to excite than the light-emitting substance y, so that when the recombination center of the light-emitting device is located near the interface between the light-emitting layers L and S, for example, the recombination energy is more likely to move to the light-emitting substance x.

[0062] Thus, one aspect of the present invention is a configuration in which, in a light-emitting device having a stacked light-emitting layer in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different emission colors are directly stacked, the recombination center of carriers (holes and electrons) is shifted from the interface between light-emitting layer L and light-emitting layer S to light-emitting layer S.

[0063] When the light-emitting device 10X has a stacked light-emitting layer constituted by two light-emitting layers (13X_1, 13X_2) and, of the two light-emitting layers (13X_1, 13X_2), for example, the light-emitting layer 13X_1 is a light-emitting layer L that emits light of a long wavelength and the light-emitting layer 13X_2 is a light-emitting layer S that emits light of a short wavelength, it is preferable to make the film thickness of the light-emitting layer L, to which recombination energy is easily transferred, thinner than the film thickness of the light-emitting layer S, so that the recombination center is shifted to the light-emitting layer S.

[0064] Specifically, in the case of a yellow (Y) light-emitting device 10X, it is preferable that the layer having the light-emitting substance R among the light-emitting layers 13X_1 and 13X_2 is thinner than the layer having the light-emitting substance G. For example, when the light-emitting layer 13X_1 is a layer having the light-emitting substance R and the light-emitting layer 13X_2 is a layer having the light-emitting substance G, it is preferable that the light-emitting layer 13X_1 is thinner than the light-emitting layer 13X_2. In addition, in the case of a magenta (M) light-emitting device 10X, it is preferable that the layer having the light-emitting substance R among the light-emitting layers 13X_1 and 13X_2 is thinner than the layer having the light-emitting substance B. For example, when the light-emitting layer 13X_1 is a layer having the light-emitting substance R and the light-emitting layer 13X_2 is a layer having the light-emitting substance B, it is preferable that the light-emitting layer 13X_1 is thinner than the light-emitting layer 13X_2. In the case of the cyan (C) light-emitting device 10X, it is preferable that the layer having the light-emitting substance G out of the light-emitting layers 13X_1 and 13X_2 is thinner than the layer having the light-emitting substance B. For example, when the light-emitting layer 13X_1 is a layer having the light-emitting substance G and the light-emitting layer 13X_2 is a layer having the light-emitting substance B, it is preferable that the light-emitting layer 13X_1 is thinner than the light-emitting layer 13X_2. With this configuration, the recombination center can be shifted to the light-emitting layer S, thereby improving the luminous intensity of the light-emitting layer S, and as a result, good light emission can be obtained from both the light-emitting layer 13X_1 and the light-emitting layer 13X_2, thereby improving the luminous efficiency of the light-emitting device 10X.

[0065] 2A and 2B show specific examples of a configuration in which the light-emitting layers 13X_1 and 13X_2 have different thicknesses. Note that, as an example, a case in which the light-emitting device 10X is a yellow (Y) light-emitting device will be described here.

[0066] In FIG. 2(A), the light-emitting layer 13X_1 is a light-emitting layer that emits light of a short wavelength and contains a light-emitting material G. The light-emitting layer 13X_2 is a light-emitting layer that emits light of a long wavelength and contains a light-emitting material R. As shown in FIG. 2(A), in this case, it is preferable that the light-emitting layer 13X_2 has a thinner film thickness than the light-emitting layer 13X_1. Here, as described above, the layer containing the light-emitting material G refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13G, and the layer containing the light-emitting material R refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13R. Therefore, in this case, it can be said that the light-emitting layer 13R is thinner than the light-emitting layer 13G.

[0067] In FIG. 2(B), the light-emitting layer 13X_1 is a light-emitting layer that emits light of a long wavelength and contains a light-emitting material R. The light-emitting layer 13X_2 is a light-emitting layer that emits light of a short wavelength and contains a light-emitting material G. As shown in FIG. 2(B), in this case, it is preferable that the light-emitting layer 13X_1 has a smaller thickness than the light-emitting layer 13X_2. In this case, the light-emitting layer 13R can be said to have a thinner thickness than the light-emitting layer 13G.

[0068] Furthermore, when the light-emitting device 10X has a stacked light-emitting layer structured by three light-emitting layers (13X_1, 13X_2, 13X_3), it is preferable to increase the thickness of the three color light-emitting layers (13X_1, 13X_2, 13X_3) in the order of the layer having the light-emitting material R, the layer having the light-emitting material G, and the layer having the light-emitting material B. This configuration allows the recombination center to be shifted from each stacking interface to the light-emitting layer that emits light of a short wavelength, thereby improving the emission intensity of the light-emitting layer that emits light of a short wavelength, and allowing good light emission from each of the light-emitting layers 13X_1, 13X_2, and 13X_3.

[0069] A specific configuration is shown in FIG. 3(B). In FIG. 3(B), the light-emitting layer 13X_1 is a layer containing a light-emitting material R. The light-emitting layer 13X_2 is a layer containing a light-emitting material G. The light-emitting layer 13X_3 is a layer containing a light-emitting material B. As shown in FIG. 3(B), in this case, it is preferable that the light-emitting layer 13X_2 is thicker than the light-emitting layer 13X_1, and the light-emitting layer 13X_3 is thicker than the light-emitting layer 13X_2. Here, as described above, the layer containing the light-emitting material G refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13G, the layer containing the light-emitting material R refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13R, and the layer containing the light-emitting material B refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13B. Therefore, in this case, it can be said that the light emitting layer 13G is thicker than the light emitting layer 13R, and the light emitting layer 13B is thicker than the light emitting layer 13G.

[0070] In other words, even in the case where the light-emitting device 10X has a stacked light-emitting layer in which a plurality of light-emitting layers with different light emission colors are directly stacked on top of each other, by reducing the thickness of the light-emitting layer that emits light of a long wavelength among the light-emitting layers constituting the stacked interface, the recombination center at the stacked interface can be shifted to the light-emitting layer that emits light of a short wavelength, thereby improving the luminous efficiency of the light-emitting device 10X.

[0071] As one aspect of the present invention, in a light-emitting device having a stacked light-emitting layer in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different light emission colors are stacked directly between a reflective electrode and a transmissive electrode, the light-emitting layer S is stacked in this order in the direction in which light is emitted (in other words, the light-emitting layer S is stacked in this order from the side closer to the reflective electrode, and the light-emitting layer L is stacked in this order). With such a configuration, the distance between the light-emitting layer S and the reflective electrode is short and the distance between the light-emitting layer L and the reflective electrode is long, making optical adjustment easy. In particular, such a configuration is more preferable in a light-emitting device having a microcavity structure because it makes optical adjustment easy. Details of the microcavity structure will be described in embodiment 3.

[0072] Therefore, in the light-emitting device 10X shown in FIG. 1(B), it is preferable that the anode 11X is a reflective electrode, the cathode 15 is a transmissive electrode, and the light-emitting layer 13X_1 of the two light-emitting layers is the light-emitting layer S, and the light-emitting layer 13X_2 is the light-emitting layer L. More specifically, in the yellow (Y) light-emitting device 10X, it is preferable that the light-emitting layer 13X_1 is a layer containing a light-emitting material G, and the light-emitting layer 13X_2 is a layer containing a light-emitting material R. Alternatively, in the magenta (M) light-emitting device 10X, it is preferable that the light-emitting layer 13X_1 is a layer containing a light-emitting material B, and the light-emitting layer 13X_2 is a layer containing a light-emitting material R. Alternatively, in the cyan (C) light-emitting device 10X, it is preferable that the light-emitting layer 13X_1 is a layer containing a light-emitting material B, and the light-emitting layer 13X_2 is a layer containing a light-emitting material G.

[0073] In another embodiment of the present invention, the stacking order of the light emitting layers L and S is changed, whereby the intensity of the light emitted by each light emitting layer changes, making it possible to adjust the chromaticity.

[0074] For example, in the light-emitting device 10X shown in FIG. 1(B), of the two light-emitting layers, the light-emitting layer 13X_1 may be the light-emitting layer L described above, and the light-emitting layer 13X_2 may be the light-emitting layer S described above. Specifically, in the yellow (Y) light-emitting device 10X, the light-emitting layer 13X_1 may be a layer containing a light-emitting material R, and the light-emitting layer 13X_2 may be a layer containing a light-emitting material G. Alternatively, in the magenta (M) light-emitting device 10X, the light-emitting layer 13X_1 may be a layer containing a light-emitting material R, and the light-emitting layer 13X_2 may be a layer containing a light-emitting material B. Alternatively, in the cyan (C) light-emitting device 10X, the light-emitting layer 13X_1 may be a layer containing a light-emitting material G, and the light-emitting layer 13X_2 may be a layer containing a light-emitting material B.

[0075] In addition, in the white (W) light-emitting device 10X shown in Figure 3 (A), of the three color light-emitting layers, the light-emitting layer 13X_1 can be a layer containing a light-emitting material R, the light-emitting layer 13X_2 can be a layer containing a light-emitting material G, and the light-emitting layer 13X_3 can be a layer containing a light-emitting material B.

[0076] Another embodiment of the present invention is a light-emitting device having a stacked light-emitting layer in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different emission colors are directly stacked, in which the carrier transportability of light-emitting layer L is increased to shift the recombination center from the interface between light-emitting layer L and light-emitting layer S to light-emitting layer S. When light-emitting device 10X has a stacked light-emitting layer in which a plurality of light-emitting layers with different emission colors are directly stacked, the recombination center at the stacked interface can be shifted to the light-emitting layer with short-wavelength emission by increasing the carrier transportability of the light-emitting layer that emits long-wavelength light among the light-emitting layers constituting the stacked interface, thereby improving the luminous efficiency of light-emitting device 10X.

[0077] In addition, when the carrier transportability of the light-emitting layer on the anode side among the above-mentioned stacked light-emitting layers is increased, it is preferable to increase the hole transportability of the light-emitting layer. That is, it is preferable that the light-emitting layer has a hole transport material, and it is more preferable that the hole transportability is higher than that of the light-emitting layer on the cathode side. In addition, when the carrier transportability of the light-emitting layer on the cathode side among the multiple light-emitting layers is increased, it is preferable to increase the electron transportability of the light-emitting layer. That is, it is preferable that the light-emitting layer has an electron transport material, and it is more preferable that the electron transportability is higher than that of the light-emitting layer on the anode side. Configuration examples of the hole transport material and the electron transport material will be described later in embodiment 3.

[0078] Therefore, in the light-emitting device 10X having two light-emitting layers, it is preferable to increase the carrier transportability of the light-emitting layer that emits light of a longer wavelength out of the light-emitting layer 13X_1 and the light-emitting layer 13X_2. For example, when the light-emitting layer 13X_1 emits light of a longer wavelength than the light-emitting layer 13X_2, it is preferable to increase the hole transportability of the light-emitting layer 13X_1. Specifically, it is preferable that the light-emitting layer 13X_1 has a hole transport material or has a higher hole transportability than the light-emitting layer 13X_2. Alternatively, when the light-emitting layer 13X_2 emits light of a longer wavelength than the light-emitting layer 13X_1, it is preferable to increase the electron transportability of the light-emitting layer 13X_2. Specifically, it is preferable that the light-emitting layer 13X_2 has an electron transport material or has a higher electron transportability than the light-emitting layer 13X_1. With such a configuration, the recombination center can be shifted from the stacking interface between the light emitting layers 13X_1 and 13X_2 to the light emitting layer that emits short wavelength light. This improves the emission intensity of the light emitting layer that emits short wavelength light, and enables good light emission to be obtained from both the light emitting layer that emits long wavelength light and the light emitting layer that emits short wavelength light.

[0079] Specifically, in the case of a yellow (Y) light-emitting device 10X, it is preferable to increase the carrier transportability of the layer having the light-emitting substance R, among the light-emitting layers 13X_1 and 13X_2. For example, when the light-emitting layer 13X_1 is a layer having the light-emitting substance R and the light-emitting layer 13X_2 is a layer having the light-emitting substance G, it is preferable that the light-emitting layer 13X_1 has a hole-transporting material or has a higher hole-transporting property than the light-emitting layer 13X_2. In addition, when the light-emitting layer 13X_1 is a layer having the light-emitting substance G and the light-emitting layer 13X_2 is a layer having the light-emitting substance R, it is preferable that the light-emitting layer 13X_2 has an electron-transporting material or has a higher electron-transporting property than the light-emitting layer 13X_1.

[0080] In the case of the magenta (M) light-emitting device 10X, it is preferable to enhance the carrier transportability of the layer having the light-emitting substance R among the light-emitting layers 13X_1 and 13X_2. For example, when the light-emitting layer 13X_1 is a layer having the light-emitting substance R and the light-emitting layer 13X_2 is a layer having the light-emitting substance B, it is preferable that the light-emitting layer 13X_1 has a hole-transporting material or has a higher hole-transporting property than the light-emitting layer 13X_2. In addition, when the light-emitting layer 13X_1 is a layer having the light-emitting substance B and the light-emitting layer 13X_2 is a layer having the light-emitting substance R, it is preferable that the light-emitting layer 13X_2 has an electron-transporting material or has a higher electron-transporting property than the light-emitting layer 13X_1.

[0081] In the case of a cyan (C) light-emitting device 10X, it is preferable to increase the carrier transport property of the layer having the light-emitting substance G among the light-emitting layers 13X_1 and 13X_2. For example, when the light-emitting layer 13X_1 is a layer having the light-emitting substance G and the light-emitting layer 13X_2 is a layer having the light-emitting substance B, it is preferable that the light-emitting layer 13X_1 has a hole-transporting material or has a higher hole-transporting property than the light-emitting layer 13X_2. In addition, when the light-emitting layer 13X_1 is a layer having the light-emitting substance B and the light-emitting layer 13X_2 is a layer having the light-emitting substance G, it is preferable that the light-emitting layer 13X_2 has an electron-transporting material or has a higher electron-transporting property than the light-emitting layer 13X_1.

[0082] As described above, the layer having the light-emitting substance R refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13R. In other words, a configuration that enhances the carrier transportability of the layer having the light-emitting substance R among the light-emitting layers 13X_1 and 13X_2 means a configuration that enhances the carrier transportability of the light-emitting layer 13R as well. In addition, when the light-emitting layer 13X_1 is a layer having the light-emitting substance R and has a hole transport material, it can be said that the light-emitting layer 13R also has a hole transport material. In addition, when the light-emitting layer 13X_2 is a layer having the light-emitting substance R and has an electron transport material, it can be said that the light-emitting layer 13R also has an electron transport material.

[0083] As described above, the layer having the light-emitting substance G refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13G. Therefore, when the light-emitting layer 13X_1 is a layer having the light-emitting substance R, the light-emitting layer 13X_2 is a layer having the light-emitting substance G, and the light-emitting layer 13X_1 has a higher hole transporting property than the light-emitting layer 13X_2, it can be said that the light-emitting layer 13R has a higher hole transporting property than the light-emitting layer 13G. When the light-emitting layer 13X_2 is a layer having the light-emitting substance R, the light-emitting layer 13X_1 is a layer having the light-emitting substance G, and the light-emitting layer 13X_2 has a higher electron transporting property than the light-emitting layer 13X_1, it can be said that the light-emitting layer 13R has a higher electron transporting property than the light-emitting layer 13G.

[0084] As described above, the layer containing the light-emitting substance B refers to a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13B. Therefore, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance R, the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, and the light-emitting layer 13X_1 has a higher hole transporting property than the light-emitting layer 13X_2, it can be said that the light-emitting layer 13R has a higher hole transporting property than the light-emitting layer 13B. When the light-emitting layer 13X_2 is a layer containing the light-emitting substance R, the light-emitting layer 13X_1 is a layer containing the light-emitting substance B, and the light-emitting layer 13X_2 has a higher electron transporting property than the light-emitting layer 13X_1, it can be said that the light-emitting layer 13R has a higher electron transporting property than the light-emitting layer 13B.

[0085] Similarly, a configuration that enhances the carrier transportability of the layer having the light-emitting substance G out of the light-emitting layers 13X_1 and 13X_2 means that a configuration that enhances the carrier transportability of the light-emitting layer 13G is also adopted. In addition, when the light-emitting layer 13X_1 is a layer having the light-emitting substance G and has a hole transporting material, it can be said that the light-emitting layer 13G also has a hole transporting material. In addition, when the light-emitting layer 13X_2 is a layer having the light-emitting substance G and has an electron transporting material, it can be said that the light-emitting layer 13G also has an electron transporting material.

[0086] Furthermore, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance G, the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, and the light-emitting layer 13X_1 has a higher hole-transporting property than the light-emitting layer 13X_2, it can be said that the light-emitting layer 13G has a higher hole-transporting property than the light-emitting layer 13B. When the light-emitting layer 13X_2 is a layer containing the light-emitting substance G, the light-emitting layer 13X_1 is a layer containing the light-emitting substance B, and the light-emitting layer 13X_2 has a higher electron-transporting property than the light-emitting layer 13X_1, it can be said that the light-emitting layer 13G has a higher electron-transporting property than the light-emitting layer 13B.

[0087] When the light-emitting layer 13R has a high carrier transport property, it is more preferable that the light-emitting device 10R has a carrier block layer in contact with the light-emitting layer 13R in order to control the recombination center in the light-emitting device 10R. When the light-emitting layer 13G has a high carrier transport property, it is more preferable that the light-emitting device 10G has a carrier block layer in contact with the light-emitting layer 13G in order to control the recombination center in the light-emitting device 10G. Examples of the carrier block layer include a hole block layer and an electron block layer.

[0088] More specifically, when the light-emitting layer 13R has a high hole transport property, the light-emitting device 10R preferably has a hole blocking layer between the light-emitting layer 13R and the cathode 15, more preferably has a hole blocking layer between the light-emitting layer 13R and the electron injection / transport layer 14, and even more preferably has a hole blocking layer in contact with the surface of the light-emitting layer 13R on the cathode 15 side. When the light-emitting layer 13R has a high electron transport property, the light-emitting device 10R preferably has an electron blocking layer between the light-emitting layer 13R and the anode 11R, more preferably has an electron blocking layer between the light-emitting layer 13R and the hole injection / transport layer 12, and even more preferably has an electron blocking layer in contact with the surface of the light-emitting layer 13R on the anode 11R side. These configurations prevent carriers from passing through the light-emitting layer 13R and facilitate recombination of carriers in the light-emitting layer 13R, thereby improving the luminous efficiency of the light-emitting device 10R.

[0089] In addition, when the light-emitting layer 13G has a high hole transport property, the light-emitting device 10G preferably has a hole block layer between the light-emitting layer 13G and the cathode 15, more preferably has a hole block layer between the light-emitting layer 13G and the electron injection / transport layer 14, and even more preferably has a hole block layer in contact with the surface of the light-emitting layer 13G on the cathode 15 side. In addition, when the light-emitting layer 13G has a high electron transport property, the light-emitting device 10G preferably has an electron block layer between the light-emitting layer 13G and the anode 11G, more preferably has an electron block layer between the light-emitting layer 13G and the hole injection / transport layer 12, and even more preferably has an electron block layer in contact with the surface of the light-emitting layer 13G on the anode 11G side. These configurations prevent carriers from passing through the light-emitting layer 13G and facilitate recombination of carriers in the light-emitting layer 13G, thereby improving the luminous efficiency of the light-emitting device 10G.

[0090] In addition, when a carrier block layer is provided in the light-emitting layer 13R, the light-emitting layer 13G, etc., the carrier block layer may be a common layer, or may be a layer formed by a vacuum deposition method using a metal mask for each device.

[0091] 4A shows an example in which the light-emitting layer 13R contains an organic compound having high hole transport properties and the hole-blocking layer is a common layer. In FIG. 4A, the hole-blocking layer 19 is a layer shared by the light-emitting devices 10R, 10G, 10B, and 10X, and is provided in contact with the cathode 15 side surface of the light-emitting layer 13R, the cathode 15 side surface of the light-emitting layer 13G, the cathode 15 side surface of the light-emitting layer 13B, and the cathode 15 side surface of the light-emitting layer 13X_2. When the hole-blocking layer is a common layer, it is not necessary to prepare a new metal mask for fabricating the hole-blocking layer, and therefore the manufacturing cost of the display device 100 can be reduced.

[0092] FIG. 4(B) shows an example in which the light-emitting layer 13X_1 is a layer containing a light-emitting material R, the light-emitting layer 13X_2 is a layer containing a light-emitting material G, the light-emitting layer 13R contains an organic compound with high hole transporting properties, and the hole-blocking layer is a layer formed by a vacuum deposition method using a metal mask. In FIG. 4(B), the light-emitting device 10R has a hole-blocking layer 19R in contact with the surface of the light-emitting layer 13R on the cathode 15 side. As shown in FIG. 4(B), when the light-emitting device 10R has the hole-blocking layer 19R, the light-emitting device 10X may have a hole-blocking layer 19X. The hole-blocking layer 19X is located between the light-emitting layer 13X_1 and the light-emitting layer 13X_2, and in contact with the surface of the light-emitting layer 13X_1 on the cathode 15 side. The hole-blocking layer 19X is a layer formed by a vacuum deposition method using a metal mask in the same process as the hole-blocking layer 19R. When the hole blocking layer 19X is formed by a vacuum deposition method using a metal mask in the same process as the hole blocking layer 19R, the hole blocking layer 19R and the hole blocking layer 19X can be formed continuously without changing the metal mask after the light emitting layer 13R and the light emitting layer 13X_1 are formed. That is, since it is not necessary to prepare a new metal mask for producing the hole blocking layer 19R and the hole blocking layer 19X, the manufacturing cost of the display device 100 can be reduced.

[0093] 5A shows an example in which the light-emitting layer 13R contains an organic compound with high electron transporting properties and the electron blocking layer is a common layer. In FIG. 5A, the electron blocking layer 20 is a layer shared by the light-emitting devices 10R, 10G, 10B, and 10X, and is provided in contact with the anode 11R side surface of the light-emitting layer 13R, the anode 11R side surface of the light-emitting layer 13G, the anode 11R side surface of the light-emitting layer 13B, and the anode 11R side surface of the light-emitting layer 13X_1. When the electron blocking layer is a common layer, it is not necessary to prepare a new metal mask for fabricating the electron blocking layer, and therefore the manufacturing cost of the display device 100 can be reduced.

[0094] FIG. 5(B) shows an example in which the light-emitting layer 13X_1 is a layer containing a light-emitting material G, the light-emitting layer 13X_2 is a layer containing a light-emitting material R, the light-emitting layer 13R contains an organic compound with high electron transporting properties, and the electron blocking layer is a layer formed by a vacuum deposition method using a metal mask. In FIG. 5(B), the light-emitting device 10R has an electron blocking layer 20R in contact with the surface of the light-emitting layer 13R on the anode 11R side. Note that, as shown in FIG. 5(B), when the light-emitting device 10R has the electron blocking layer 20R, the light-emitting device 10X may have an electron blocking layer 20X. The electron blocking layer 20X is located between the light-emitting layer 13X_1 and the light-emitting layer 13X_2, and in contact with the surface of the light-emitting layer 13X_2 on the anode 11X side. The electron blocking layer 20X is a layer formed by a vacuum deposition method using a metal mask in the same process as the electron blocking layer 20R. When the electron blocking layer 20X is formed by a vacuum deposition method using a metal mask in the same process as the electron blocking layer 20R, after the electron blocking layer 20R and the electron blocking layer 20X are formed, the light-emitting layer 13R and the light-emitting layer 13X_2 can be formed continuously without changing the metal mask. In other words, since there is no need to prepare a new metal mask to fabricate the electron blocking layer 20R and the electron blocking layer 20X, the manufacturing cost of the display device 100 can be reduced.

[0095] FIG. 6 shows an example in which the hole blocking layer and the electron blocking layer are formed by a vacuum deposition method using a metal mask. In FIG. 6, the light-emitting layer 13X_1 is a layer containing a light-emitting material R, and the light-emitting layer 13X_2 is a layer containing a light-emitting material G. In FIG. 6, the light-emitting device 10R has a hole blocking layer 19R in contact with the surface of the light-emitting layer 13R on the cathode 15 side. In addition, the light-emitting device 10G has an electron blocking layer 20G in contact with the surface of the light-emitting layer 13G on the anode 11G side. As shown in FIG. 6, when the light-emitting device 10R has the hole blocking layer 19R, the light-emitting device 10X may have a hole blocking layer 19X. The hole blocking layer 19X is located between the light-emitting layer 13X_1 and the light-emitting layer 13X_2, and is in contact with the surface of the light-emitting layer 13X_1 on the cathode 15 side. The hole blocking layer 19X is a layer formed by a vacuum deposition method using a metal mask in the same process as the hole blocking layer 19R. Furthermore, as shown in FIG. 6, when the light emitting device 10G has the electron blocking layer 20G, the light emitting device 10X may have the electron blocking layer 20X. The electron blocking layer 20X is located between the light emitting layer 13X_1 and the light emitting layer 13X_2, and contacts the surface of the light emitting layer 13X_2 on the anode 11X side. The electron blocking layer 20X is a layer formed by a vacuum deposition method using a metal mask in the same process as the electron blocking layer 20G. In this way, it is possible to have both a hole blocking layer and an electron blocking layer in order to control the carrier balance.

[0096] When the carrier block layer is formed by a vacuum deposition method using a metal mask, as shown in FIG. 4(B), FIG. 5(B), and FIG. 6, the carrier block layer may be sandwiched between the light emitting layer 13X_1 and the light emitting layer 13X_2 of the light emitting device 10X. In such a configuration, it is more preferable that the carrier block layer has a bipolar configuration or a thin film thickness. When the carrier block layer is formed by a vacuum deposition method using a metal mask, the film thickness is preferably 1 nm or more and 20 nm or less, and more preferably 3 nm or more and 10 nm or less. This can increase the luminous efficiency of the light emitting device 10X.

[0097] Another method for solving the above problem is to sandwich an emission layer S between two emission layers L. This method makes it easier for the recombination center to overlap with the emission layer S, making it easier for the emission layer S to obtain energy.

[0098] Therefore, the light-emitting device 10X may be a light-emitting device having a light-emitting layer configured by laminating the light-emitting layer 13X_1h, the light-emitting layer 13X_1e, and the light-emitting layer 13X_2 sandwiched between the light-emitting layer 13X_1h and the light-emitting layer 13X_1e. However, the light-emitting layer 13X_1h and the light-emitting layer 13X_1e each have the same light-emitting material, and the light-emitting layer 13X_2 has a light-emitting material different from the light-emitting layer 13X_1h and the light-emitting layer 13X_1e. For example, it is preferable that the light-emitting layer 13X_1h and the light-emitting layer 13X_1e are layers having the light-emitting material R, and the light-emitting layer 13X_2 is a layer having the light-emitting material G or a layer having the light-emitting material B, because it is easier for the light-emitting layer 13X_2 to obtain energy. Also, for example, it is preferable that the light-emitting layer 13X_1h and the light-emitting layer 13X_1e are layers having the light-emitting material G, and the light-emitting layer 13X_2 is a layer having the light-emitting material B, because it is easier for the light-emitting layer 13X_2 to obtain energy. With this configuration, in the light-emitting device 10X, the light-emitting layer 13X_2, which is a layer having a light-emitting material with a shorter peak wavelength of the emission spectrum, is sandwiched between the light-emitting layers 13X_1h and 13X_1e, which are layers having a light-emitting material with a longer peak wavelength of the emission spectrum, and the recombination center can be located in the light-emitting layer 13X_2. Therefore, good light emission can be achieved from all of the light-emitting layers 13X_1h, 13X_1e, and 13X_2.

[0099] The materials other than the light-emitting substance of the light-emitting layer 13X_1h and the light-emitting layer 13X_1e may be different from each other. For example, the layer of the light-emitting layer 13X_1h and the light-emitting layer 13X_1e located on the anode 11X side may be a layer having a hole transporting material, and the layer located on the cathode 15 side may be a layer having an electron transporting material. This can increase the luminous efficiency of the light-emitting layer 13X_2.

[0100] Fig. 7 shows an example in which the light-emitting layer 13X_1h and the light-emitting layer 13X_1e are layers containing a light-emitting material R, and the light-emitting layer 13X_2 is a layer containing a light-emitting material G. In Fig. 7, it is preferable that the light-emitting layer 13X_1h located on the anode 11X side contains a hole-transporting material, and the light-emitting layer 13X_1e located on the cathode 15 side contains an electron-transporting material.

[0101] In this case, the light-emitting layer 13X_1h is a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13R_h, and the light-emitting layer 13X_1e is a layer formed by a vacuum deposition method using a metal mask in the same process as the light-emitting layer 13R_e. Therefore, it is preferable that the light-emitting layer 13R_h has a hole transporting material and the light-emitting layer 13R_e has an electron transporting material.

[0102] In the configuration shown in FIG. 7, it is more preferable to use a hole transporting material for the light emitting layer 13R_h and the light emitting layer 13X_1h, and to use an electron transporting material for the light emitting layer 13R_e and the light emitting layer 13X_1e.

[0103] In addition, the light-emitting devices 10R, 10G, 10B, and 10X may be so-called tandem-type light-emitting devices in which an intermediate layer (charge generating layer) is provided between a plurality of light-emitting layers. Fig. 8(A) shows an example in which the light-emitting devices 10R, 10G, 10B, and 10X are tandem-type light-emitting devices.

[0104] As shown in FIG. 8(A), in the display device 100, an anode 11R, an anode 11G, an anode 11B, and an anode 11X are provided on a layer 121, a first hole injection / transport layer 12_a is provided on the anode 11R, the anode 11G, the anode 11B, and the anode 11X, a first light-emitting layer 13R_a, a first light-emitting layer 13G_a, a first light-emitting layer 13B_a, and a first light-emitting layer 13X_a are provided on the first hole injection / transport layer 12_a, a first electron injection / transport layer 14_a is provided on the first light-emitting layer 13R_a, the first light-emitting layer 13G_a, the first light-emitting layer 13B_a, and the first light-emitting layer 13X_a, and a first electron injection / transport layer 14_a is provided on the first light-emitting layer 13R_a, the first light-emitting layer 13G_a, the first light-emitting layer 13B_a, and the first light-emitting layer 13X_a. An intermediate layer 21 is provided on the hole injection / transport layer 14_a, a second hole injection / transport layer 12_b is provided on the intermediate layer 21, a second light-emitting layer 13R_b, a second light-emitting layer 13G_b, a second light-emitting layer 13B_b, and a second light-emitting layer 13X_b are provided on the second hole injection / transport layer 12_b, a second electron injection / transport layer 14_b is provided on the second light-emitting layer 13R_b, the second light-emitting layer 13G_b, the second light-emitting layer 13B_b, and the second light-emitting layer 13X_b, and a cathode 15 is formed on the second electron injection / transport layer 14_b, thereby providing tandem light-emitting devices 10R, 10G, 10B, 10X.

[0105] It is preferable that the first hole injection / transport layer 12_a, the second hole injection / transport layer 12_b, the intermediate layer 21, the first electron injection / transport layer 14_a, the second electron injection / transport layer 14_b, and the cathode 15 are a common layer. It is also preferable that the first light-emitting layers 13R_a, 13G_a, 13B_a, 13X_a, and the second light-emitting layers 13R_b, 13G_b, 13B_b, 13X_b are layers formed for each device by a vacuum deposition method using a metal mask.

[0106] The tandem light-emitting device 10R has a first light-emitting layer 13R_a, a second light-emitting layer 13R_b, and an intermediate layer 21 between the anode 11R and the cathode 15, and the intermediate layer 21 is located between the first light-emitting layer 13R_a and the second light-emitting layer 13R_b. The first light-emitting layer 13R_a is located between the anode 11R and the intermediate layer 21. The second light-emitting layer 13R_b is located between the intermediate layer 21 and the cathode 15. The tandem light-emitting device 10R also has a first hole injection / transport layer 12_a, a first electron injection / transport layer 14_a, a second hole injection / transport layer 12_b, and a second electron injection / transport layer 14_b. The first hole injection / transport layer 12_a is located between the anode 11R and the first light-emitting layer 13R_a, the first electron injection / transport layer 14_a is located between the first light-emitting layer 13R_a and the intermediate layer 21, the second hole injection / transport layer 12_b is located between the intermediate layer 21 and the second light-emitting layer 13R_b, and the second electron injection / transport layer 14_b is located between the second light-emitting layer 13R_b and the cathode 15. Each of the first light-emitting layer 13R_a and the second light-emitting layer 13R_b contains at least a light-emitting material R.

[0107] The tandem light-emitting device 10G has a first light-emitting layer 13G_a, a second light-emitting layer 13G_b, and an intermediate layer 21 between an anode 11G and a cathode 15, and the intermediate layer 21 is located between the first light-emitting layer 13G_a and the second light-emitting layer 13G_b. The first light-emitting layer 13G_a is located between the anode 11G and the intermediate layer 21. The second light-emitting layer 13G_b is located between the intermediate layer 21 and the cathode 15. The tandem light-emitting device 10G also has a first hole injection / transport layer 12_a, a first electron injection / transport layer 14_a, a second hole injection / transport layer 12_b, and a second electron injection / transport layer 14_b. The first hole injection / transport layer 12_a is located between the anode 11G and the first light-emitting layer 13G_a, the first electron injection / transport layer 14_a is located between the first light-emitting layer 13G_a and the intermediate layer 21, the second hole injection / transport layer 12_b is located between the intermediate layer 21 and the second light-emitting layer 13G_b, and the second electron injection / transport layer 14_b is located between the second light-emitting layer 13G_b and the cathode 15. Each of the first light-emitting layer 13G_a and the second light-emitting layer 13G_b contains at least a light-emitting material G.

[0108] The tandem light-emitting device 10B has a first light-emitting layer 13B_a, a second light-emitting layer 13B_b, and an intermediate layer 21 between the anode 11B and the cathode 15, and the intermediate layer 21 is located between the first light-emitting layer 13B_a and the second light-emitting layer 13B_b. The first light-emitting layer 13B_a is located between the anode 11B and the intermediate layer 21. The second light-emitting layer 13B_b is located between the intermediate layer 21 and the cathode 15. The tandem light-emitting device 10B also has a first hole injection / transport layer 12_a, a first electron injection / transport layer 14_a, a second hole injection / transport layer 12_b, and a second electron injection / transport layer 14_b. The first hole injection / transport layer 12_a is located between the anode 11B and the first light-emitting layer 13B_a, the first electron injection / transport layer 14_a is located between the first light-emitting layer 13B_a and the intermediate layer 21, the second hole injection / transport layer 12_b is located between the intermediate layer 21 and the second light-emitting layer 13B_b, and the second electron injection / transport layer 14_b is located between the second light-emitting layer 13B_b and the cathode 15. Each of the first light-emitting layer 13B_a and the second light-emitting layer 13B_b contains at least a light-emitting material B.

[0109] In the tandem light-emitting device 10X, an anode 11X, a first hole injection / transport layer 12_a, a first light-emitting layer 13X_a, a first electron injection / transport layer 14_a, an intermediate layer 21, a second hole injection / transport layer 12_b, a second light-emitting layer 13X_b, a second electron injection / transport layer 14_b, and a cathode 15 are laminated in this order. The first light-emitting layer 13X_a and the second light-emitting layer 13X_b each contain a different light-emitting material.

[0110] The first light-emitting layer 13X_a is a layer formed by a vacuum deposition method using a metal mask in the same process as the first light-emitting layer 13R_a, 13G_a, or 13B_a, while the second light-emitting layer 13X_b is a layer formed by a vacuum deposition method using a metal mask in the same process as the second light-emitting layer 13R_b, 13G_b, or 13B_b.

[0111] Even in a display device having a tandem-type light-emitting device, since the light-emitting device 10X can be provided in the display device 100, the light-emitting device 10X can be manufactured without adding any new processes or materials, thereby reducing the cost of the display device 100.

[0112] The intermediate layer 21 is a layer containing an organic compound and an alkali metal or an alkaline earth metal. As described above, the intermediate layer 21 is preferably a common layer. Therefore, the intermediate layer 21 in the light-emitting device 10R, the intermediate layer 21 in the light-emitting device 10G, the intermediate layer 21 in the light-emitting device 10B, and the intermediate layer 21 in the light-emitting device 10X each preferably contains an organic compound and an alkali metal or an alkaline earth metal, and more preferably contains the same organic compound and the same alkali metal or alkaline earth metal.

[0113] The tandem light-emitting device 10X may have a third light-emitting layer 13X_c that is a layer having a light-emitting material different from the first light-emitting layer 13X_a and the second light-emitting layer 13X_b. The third light-emitting layer 13X_c is preferably provided in contact with the first light-emitting layer 13X_a or the second light-emitting layer 13X_b. Fig. 8(B) shows a display device having a light-emitting device 10X that is a modification of Fig. 8(A) and has a third light-emitting layer 13X_c in contact with the surface of the first light-emitting layer 13X_a on the cathode 15 side.

[0114] 8(B), when the third light-emitting layer 13X_c is provided at a position in contact with the first light-emitting layer 13X_a, the third light-emitting layer 13X_c can be formed by a vacuum deposition method using a metal mask in the same process as the first light-emitting layer 13R_a, 13G_a, or 13B_a. Although not shown, when the third light-emitting layer 13X_c is provided at a position in contact with the second light-emitting layer 13X_b, the third light-emitting layer 13X_c can be formed by a vacuum deposition method using a metal mask in the same process as the second light-emitting layer 13R_b, 13G_b, or 13B_b.

[0115] Even when the third light-emitting layer 13X_c is provided, the light-emitting device 10X can be manufactured without adding any new steps or materials in order to provide the light-emitting device 10X, so that the cost of the display device 100 can be reduced.

[0116] In the tandem light-emitting device 10X, when the third light-emitting layer 13X_c is provided in contact with the first light-emitting layer 13X_a or the second light-emitting layer 13X_b, the light-emitting intensity of the light-emitting layer L that emits light of a long wavelength may be stronger than the light-emitting intensity of the light-emitting layer S that emits light of a short wavelength, as in the case of the single light-emitting device 10X. Therefore, the stacking order of the stacked light-emitting layers, the configuration of each light-emitting layer, the film thickness of each light-emitting layer, the electron blocking layer, the hole blocking layer, and the like described in the single light-emitting device 10X may be applied to the tandem light-emitting device 10X. In the case where the third light-emitting layer 13X_c is provided in contact with the first light-emitting layer 13X_a, the intermediate layer 21 corresponds to the cathode 15 in the single light-emitting device 10X, and in the case where the third light-emitting layer 13X_c is provided in contact with the second light-emitting layer 13X_b, the intermediate layer 21 corresponds to the anode 11X in the single light-emitting device 10X.

[0117] 8(C) shows an example of a tandem light-emitting device 10X having a third light-emitting layer 13X_c in contact with the surface of the second light-emitting layer 13X_b on the cathode 15 side, the third light-emitting layer 13X_c being a layer formed by a vacuum deposition method using a metal mask in the same process as the second light-emitting layer 13R_b, and having a hole-blocking layer 19. For example, when the third light-emitting layer 13X_c and the second light-emitting layer 13R_b contain an organic compound with high hole-transporting properties, providing the hole-blocking layer 19 in this manner prevents holes from passing through the second light-emitting layer 13R_b in the tandem light-emitting device 10R, and facilitates carrier recombination in the light-emitting layer 13R, thereby improving the luminous efficiency of the light-emitting device 10R.

[0118] Other configurations of the tandem light emitting device 10X are similar to those of the single light emitting device 10X, and therefore descriptions thereof will be omitted. Also, other configurations of the display device having the tandem light emitting device are similar to those of the display device having the single light emitting device, and therefore descriptions thereof will be omitted.

[0119] In the display device 100 shown in FIG. 1A, the pixel 110 is composed of four subpixels. However, in the display device according to one embodiment of the present invention, the pixel may be composed of four or more subpixels. FIG. 9A shows a display device 100A which is a modification of the display device 100. In the display device 100A, the pixel 110 shown in FIG. 9A is composed of six subpixels, namely, a subpixel 50R, a subpixel 50G, a subpixel 50B, a subpixel 50Y, a subpixel 50C, and a subpixel 50M. The subpixels 50R, 50G, 50B, 50Y, 50C, and 50M emit light of different colors. Examples of the subpixels 50R, 50G, and 50B include red (R), green (G), and blue (B) subpixels. Examples of the subpixels 50Y, 50C, and 50M include yellow (Y), cyan (C), and magenta (M) subpixels.

[0120] FIG. 9B shows a cross-sectional view taken along dashed line X3-X4 in FIG.

[0121] In the display device 100A, light-emitting device 10R, light-emitting device 10G, light-emitting device 10B, light-emitting device 10Y, light-emitting device 10M, and light-emitting device 10C are provided on a layer 121, and a protective layer 122 is provided to cover these light-emitting devices. A substrate 124 is further attached thereon by a resin layer 123. An insulating layer 125 is provided in the region between adjacent light-emitting devices.

[0122] The light emitted by the light-emitting device 10R, the light emitted by the light-emitting device 10G, the light emitted by the light-emitting device 10B, the light emitted by the light-emitting device 10Y, the light emitted by the light-emitting device 10M, and the light emitted by the light-emitting device 10C are different in color from one another. For example, it is preferable that the light-emitting device 10R emits red (R) light, the light-emitting device 10G emits green (G) light, the light-emitting device 10B emits blue (B) light, the light-emitting device 10Y emits yellow (Y) light, the light-emitting device 10M emits magenta (M) light, and the light-emitting device 10C emits cyan (C) light.

[0123] As shown in FIG. 9(B), in the display device 100A, the anode 11R, the anode 11G, the anode 11B, the anode 11Y, the anode 11M, and the anode 11C are provided on the layer 121, the hole injection / transport layer 12 is provided on the anode 11R, the anode 11G, the anode 11B, the anode 11Y, the anode 11M, and the anode 11C, the light-emitting layer 13R, the light-emitting layer 13G, the light-emitting layer 13B, the light-emitting layer 13Y_1, the light-emitting layer 13M_1, and the light-emitting layer 13C_1 are provided on the hole injection / transport layer 12, and the light-emitting layer Light-emitting layer 13Y_2 is provided on light-emitting layer 13Y_1, light-emitting layer 13M_2 is provided on light-emitting layer 13M_1, light-emitting layer 13C_2 is provided on light-emitting layer 13C_1, electron injection / transport layer 14 is provided on light-emitting layer 13R, light-emitting layer 13G, light-emitting layer 13B, light-emitting layer 13Y_2, light-emitting layer 13M_2, and light-emitting layer 13C_2, and cathode 15 is formed on electron injection / transport layer 14, thereby providing light-emitting devices 10R, 10G, 10B, 10Y, 10M, and 10C.

[0124] The light-emitting device 10Y has the same configuration as the yellow (Y) light-emitting device 10X, that is, the light-emitting device 10Y has a stacked structure of two color light-emitting layers (13Y_1, 13Y_2), one of which is a layer containing a light-emitting material R and the other is a layer containing a light-emitting material G.

[0125] The light-emitting device 10M has the same configuration as the magenta (M) light-emitting device 10X, i.e., the light-emitting device 10M has a stacked structure of two color light-emitting layers (13M_1, 13M_2), one of which is a layer containing a light-emitting material R and the other is a layer containing a light-emitting material B.

[0126] The light-emitting device 10C has the same configuration as the cyan (C) light-emitting device 10X, that is, the light-emitting device 10C has a stacked structure of two color light-emitting layers (13C_1, 13C_2), one of which is a layer containing a light-emitting material G and the other is a layer containing a light-emitting material B.

[0127] The other configuration of the display device 100A is similar to that of the display device 100, and therefore the description thereof will be omitted.

[0128] By configuring the pixel 110 to have six sub-pixels, as in the configuration of the display device 100A, it is possible to increase the number of color gradations of the display device 100A.

[0129] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0130] (Embodiment 2) In this embodiment, a manufacturing method of a display device 100A which is a display device of one embodiment of the present invention will be described with reference to cross-sectional views of the display device 100A taken along dashed dotted line X3-X4 in FIG. 9A.

[0131] The thin films (insulating film, semiconductor film, conductive film, etc.) constituting the display device can be formed by using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum deposition method, a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. Another thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0132] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating, and knife coating.

[0133] In particular, for the production of light-emitting devices, vacuum processes such as deposition methods and solution processes such as spin coating and inkjet methods can be used. Examples of deposition methods include physical deposition methods (PVD methods) such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, and chemical deposition methods (CVD methods). In particular, functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, etc.) included in the EL layer can be formed by methods such as deposition methods (vacuum deposition methods, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet methods, screen (screen printing) methods, offset (lithographic printing) methods, flexo (relief printing) methods, gravure methods, microcontact methods, etc.).

[0134] Furthermore, when processing the thin film constituting the display device, it can be processed using a photolithography method or the like. Alternatively, the thin film may be processed using a nanoimprint method, a sandblasting method, a lift-off method, or the like. Furthermore, an island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0135] There are two typical photolithography methods. One is a method in which a resist mask is formed on the thin film to be processed, the thin film is processed by etching or the like, and the resist mask is then removed. The other is a method in which a photosensitive thin film is formed, and then exposed and developed to process the thin film into the desired shape.

[0136] In the photolithography method, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. In addition, ultraviolet light, KrF laser light, ArF laser light, or the like may be used. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays may also be used as the light used for exposure. An electron beam may also be used instead of the light used for exposure. Extreme ultraviolet light, X-rays, or an electron beam are preferable because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0137] For etching the thin film, a dry etching method, a wet etching method, a sandblasting method, or the like can be used.

[0138] First, the anodes 11R, 11G, 11B, 11Y, 11M, and 11C are formed on a layer 121 including a transistor (not shown) (see FIG. 10(A)). First, a metal film is formed on the layer 121, and then a resist mask is formed by photolithography, and unnecessary portions of the conductive film are removed by etching. Then, the resist mask is removed, whereby the anodes 11R, 11G, 11B, 11Y, 11M, and 11C can be formed.

[0139] Next, an insulating layer 125 is formed to cover the layer 121 and the ends of the anodes 11R, 11G, 11B, 11Y, 11M, and 11C (see FIG. 10B).

[0140] Next, the hole injection / transport layer 12 is formed on the anodes 11R, 11G, 11B, 11Y, 11M, and 11C and the insulating layer 125 (see FIG. 10(C)).

[0141] Next, the light-emitting layers 13R, 13Y_1, and 13M_1 are formed on the hole injection / transport layer 12 at positions overlapping with the anodes 11R, 11Y, and 11M (see FIG. 10(D)).

[0142] It is preferable that the light-emitting layers 13R, 13Y_1, and 13M_1 are formed in the same process by a vacuum deposition method using a metal mask. By doing so, it is not necessary to add new processes or materials to provide the light-emitting layers 13Y_1 and 13M_1 in addition to the light-emitting layer 13R, and therefore the manufacturing cost can be reduced.

[0143] Subsequently, light-emitting layers 13G and 13C_1 are formed on the hole injection / transport layer 12 at positions overlapping with the anodes 11G and 11C, and a light-emitting layer 13Y_2 is formed on the light-emitting layer 13Y_1 (see FIG. 11(A)).

[0144] The light-emitting layers 13G, 13Y_2, and 13C_1 are preferably formed in the same process by a vacuum deposition method using a metal mask, which eliminates the need for additional processes and materials to provide the light-emitting layers 13Y_2 and 13C_1 in addition to the light-emitting layer 13G, thereby reducing manufacturing costs.

[0145] Furthermore, a light-emitting layer 13B is formed on the hole injection / transport layer 12 at a position overlapping with the anode 11B, a light-emitting layer 13M_2 is formed on the light-emitting layer 13M_1, and a light-emitting layer 13C_2 is formed on the light-emitting layer 13C_1 (see FIG. 11(B)).

[0146] The light-emitting layers 13B, 13M_2, and 13C_2 are preferably formed in the same process by a vacuum deposition method using a metal mask. By doing so, it is not necessary to add new processes or materials to provide the light-emitting layers 13M_2 and 13C_2 in addition to the light-emitting layer 13G, and therefore the manufacturing cost can be reduced.

[0147] In the above-mentioned manufacturing method, the light-emitting layer 13R is formed first, then the light-emitting layer 13G is formed, and finally the light-emitting layer 13B is formed. However, the order of forming the light-emitting layers 13R, 13G, and 13B is not limited to this. For example, the order may be such that the light-emitting layer 13B is formed first, then the light-emitting layer 13G is formed, and finally the light-emitting layer 13R is formed. In this case, it is preferable to form the light-emitting layers 13M_1 and 13C_1 in the same process as the light-emitting layer 13B. It is also preferable to form the light-emitting layers 13Y_1 and 13C_2 in the same process as the light-emitting layer 13G. It is also preferable to form the light-emitting layers 13Y_2 and 13M_2 in the same process as the light-emitting layer 13R.

[0148] Next, the electron injection / transport layer 14 is formed on the light emitting layers 13R, 13G, 13B, 13Y_2, 13M_2, and 13C_2 (see FIG. 11C).

[0149] Next, the light emitting devices 10R, 10G, 10B, 10Y, 10M, and 10C are provided by forming the cathode 15 (FIG. 11(D)) on the electron injection / transport layer 14. The cathode 15 can be formed by, for example, sputtering or vacuum deposition.

[0150] Then, a protective layer 122 is formed on the cathode 15 so as to cover the light emitting devices 10R, 10G, 10B, 10Y, 10M, and 10C (FIG. 12(A)).

[0151] Finally, a substrate 124 is attached with a resin layer 123, so that a display device of one embodiment of the present invention can be manufactured (FIG. 12B).

[0152] By manufacturing the display device of one embodiment of the present invention by the above-described manufacturing method, the light-emitting devices 10Y, 10M, and 10C can be formed in addition to the light-emitting devices 10R, 10G, and 10B without adding any new steps or materials, thereby reducing the manufacturing cost.

[0153] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0154] (Embodiment 3) In this embodiment, a structure of a light-emitting device that can be used for a display device of one embodiment of the present invention will be described with reference to FIGS.

[0155] <Basic structure of light-emitting devices> The basic structure of a light-emitting device will be described. Fig. 13(A) shows a light-emitting device having an EL layer (also called an organic compound layer) including a light-emitting layer between a pair of electrodes. Specifically, the device has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102.

[0156] 13(B) shows a light-emitting device having a stacked structure (tandem structure) that has multiple EL layers (2 layers in FIG. 13(B)) (103a, 103b) between a pair of electrodes and has a charge generating layer 106 between the EL layers. A light-emitting device with a tandem structure can realize a highly efficient light-emitting device without changing the amount of current.

[0157] The charge generation layer 106 has a function of injecting electrons into one EL layer (103a or 103b) and injecting holes into the other EL layer (103b or 103a) when a potential difference is generated between the first electrode 101 and the second electrode 102. Therefore, in Fig. 13(B), when a voltage is applied to the first electrode 101 so that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 106 into the EL layer 103a and holes are injected into the EL layer 103b.

[0158] From the viewpoint of light extraction efficiency, the charge generation layer 106 preferably has a visible light transmitting property (specifically, the visible light transmittance of the charge generation layer 106 is 40% or more). The charge generation layer 106 functions even if it has a lower electrical conductivity than the first electrode 101 and the second electrode 102.

[0159] FIG. 13(C) shows a laminated structure of the EL layer 103 of the light-emitting device. In this case, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are laminated in this order on the first electrode 101. The laminated structure of the hole injection layer 111 and the hole transport layer 112 may be collectively called a hole injection / transport layer, as shown in the first embodiment. The laminated structure of the electron transport layer 114 and the electron injection layer 115 may be collectively called an electron injection / transport layer, as shown in the first embodiment. The light-emitting layer 113 may have a structure in which a plurality of light-emitting layers emitting different luminescent colors are laminated so as to be in contact with each other, as shown in the first embodiment. In addition, when the first electrode 101 is a cathode and the second electrode 102 is an anode, the stacking order of the EL layer 103 is reversed. Specifically, on the first electrode 101 which is a cathode, 111 is an electron injection layer, 112 is an electron transport layer, 113 is a light-emitting layer, 114 is a hole transport layer, and 115 is a hole injection layer.

[0160] FIG. 13D shows a modified example of the laminated structure shown in FIG. 13C. In this case, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. In this modified example, a hole blocking layer and an electron blocking layer are provided. That is, the EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, an electron blocking layer 116, a light-emitting layer 113, a hole blocking layer 117, an electron transport layer 114, and an electron injection layer 115 are sequentially laminated on the first electrode 101. The light-emitting layer 113 is located between the first electrode 101 and the second electrode 102. As shown in the first embodiment, the light-emitting layer 113 may have a structure in which a plurality of light-emitting layers having different light-emitting colors are laminated so as to be in contact with each other. The hole transport layer 112 is located between the first electrode 101 and the light-emitting layer 113. In addition, the electron transport layer 114 is located between the light emitting layer 113 and the second electrode 102. In addition, the hole injection layer 111 is located between the first electrode 101 and the hole transport layer 112. In addition, the electron injection layer 115 is located between the electron transport layer 114 and the second electrode 102. In addition, the electron blocking layer 116 is located between the hole transport layer 112 and the light emitting layer 113. In other words, the hole blocking layer 117 is located between the light emitting layer 113 and the electron transport layer 114.

[0161] The electron blocking layer 116 is provided, for example, for the purpose of preventing electrons from passing through from the light emitting layer 113 to the first electrode 101. The hole blocking layer 117 is provided, for example, for the purpose of preventing holes from passing through from the light emitting layer 113 to the second electrode 102.

[0162] The light-emitting device shown in FIG. 13(E) is an example of a light-emitting device having the tandem structure shown in FIG. 13(B), and has a structure in which two EL layers (103a, 103b) are stacked with a charge generating layer (106) sandwiched therebetween, as shown in the figure. The two EL layers (103a, 103b) each have a light-emitting layer (113a, 113b), and the light-emitting colors of each light-emitting layer can be freely combined. In addition, the light-emitting layers (113a, 113b) may be stacked so that a plurality of light-emitting layers having different light-emitting colors are in contact with each other, as shown in the first embodiment. Since it has a microcavity structure, it is possible to extract light of different wavelengths (monochromatic light) from each EL layer (103a, 103b). Details of the microcavity structure will be described in <<Specific Structure of Light-Emitting Device>>. Therefore, it is not necessary to paint different colors (for example, RGB) to obtain different light-emitting colors. Therefore, it is easy to realize high definition. It is also possible to combine it with a colored layer (color filter). Furthermore, since it is possible to increase the emission intensity of a specific wavelength in the front direction, it is possible to reduce power consumption.

[0163] The light-emitting device shown in FIG. 13(F) is an example of the light-emitting device with the tandem structure shown in FIG. 13(B), and has a structure in which three EL layers (103a, 103b, 103c) are stacked with charge generating layers (106a, 106b) sandwiched therebetween, as shown in the figure. The three EL layers (103a, 103b, 103c) each have a light-emitting layer (113a, 113b, 113c), and the light-emitting colors of the light-emitting layers can be freely combined. For example, the light-emitting layer 113a can be blue, the light-emitting layer 113b can be red, green, or yellow, and the light-emitting layer 113c can be blue, but it is also possible to make the light-emitting layer 113a red, the light-emitting layer 113b blue, green, or yellow, and the light-emitting layer 113c red. Furthermore, the light emitting layers (113a, 113b, 113c) may have a laminated structure in which a plurality of light emitting layers emitting different colors of light are in contact with each other, as in the first embodiment.

[0164] <Specific structure of light-emitting device> Next, a specific structure of a light-emitting device according to one embodiment of the present invention will be described. Here, the description will be given with reference to Fig. 13(E) having a tandem structure. Note that the structure of the EL layer of the light-emitting device having a single structure shown in Fig. 13(A), Fig. 13(C), and Fig. 13(D) is the same as the structure of the EL layer of the light-emitting device having a tandem structure described below.

[0165] <First electrode and second electrode> As the material for forming the first electrode 101 and the second electrode 102, the following materials can be used in appropriate combination as long as the above-mentioned functions of both electrodes are satisfied. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used appropriately. Specific examples include In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, and In-W-Zn oxide. In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), and alloys containing these in appropriate combinations can also be used. Other examples that can be used include elements belonging to Group 1 or 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)) that are not listed above, rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing appropriate combinations of these, as well as graphene.

[0166] 13(E), when the first electrode 101 is an anode, the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a are successively laminated by vacuum deposition on the first electrode 101. After the EL layer 103a and the charge generation layer 106 are formed, the hole injection layer 111b and the hole transport layer 112b of the EL layer 103b are similarly successively laminated on the charge generation layer 106.

[0167] In addition, in each light-emitting device shown in Figure 13, the first electrode 101 is a reflective electrode, the second electrode 102 is a semi-transparent and semi-reflective electrode, and a micro-optical resonator (microcavity) structure is formed, so that the light emitted from the light-emitting layer 113 included in the EL layer 103 can be resonated between the two electrodes, thereby enhancing the light emitted from the second electrode 102.

[0168] In addition, when the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a conductive material having reflectivity and a conductive material having light transmission (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust the optical distance (product of film thickness and refractive index) between the first electrode 101 and the second electrode 102 to mλ / 2 (where m is an integer of 1 or more) or its vicinity, for the wavelength λ of light obtained from the light-emitting layer 113.

[0169] In order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained and the optical distance from the second electrode 102 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained to (2m'+1)λ / 4 (where m' is an integer of 1 or more) or close thereto. Note that the light-emitting region referred to here refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0170] By carrying out such optical adjustment, it is possible to narrow the spectrum of the specific monochromatic light obtained from the light-emitting layer 113, and to obtain light emission with excellent color purity.

[0171] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can be strictly said to be the total thickness from the reflection area in the first electrode 101 to the reflection area in the second electrode 102. However, since it is difficult to strictly determine the reflection areas in the first electrode 101 and the second electrode 102, it is assumed that the above-mentioned effect can be sufficiently obtained by assuming any position of the first electrode 101 and the second electrode 102 as the reflection area. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be strictly said to be the optical distance between the reflection area in the first electrode 101 and the light-emitting area in the light-emitting layer from which the desired light is obtained. However, since it is difficult to strictly determine the reflection area in the first electrode 101 and the light-emitting area in the light-emitting layer from which the desired light is obtained, it is assumed that the above-mentioned effect can be sufficiently obtained by assuming any position of the first electrode 101 as the reflection area and any position of the light-emitting layer from which the desired light is obtained as the light-emitting area.

[0172] In the light-emitting device according to one embodiment of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is an electrode having translucency (such as a transparent electrode or a semi-transparent / semi-reflective electrode). When the electrode having translucency is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. When the electrode is a semi-transparent / semi-reflective electrode, the visible light reflectance of the semi-transparent / semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, these electrodes have a resistivity of 1×10 -2 It is preferable to set it to Ωcm or less.

[0173] In the above-described light-emitting device according to one embodiment of the present invention, when one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100%. -2 It is preferable to set it to Ωcm or less.

[0174] <Hole injection layer> The hole injection layers (111, 111a, 111b) are layers that inject holes from the first electrode 101, which is an anode, and the charge generation layers (106, 106a, 106b) to the EL layers (103, 103a, 103b), and contain an organic acceptor material and a material with high hole injection properties.

[0175] An organic acceptor material is a material that can generate holes in an organic compound by charge separation between the organic compound and another organic compound whose LUMO level and HOMO level are close to each other. Therefore, as the organic acceptor material, a compound having an electron-withdrawing group (a halogen group or a cyano group), such as a quinodimethane derivative, a chloranil derivative, or a hexaazatriphenylene derivative, can be used. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like can be used. Among organic acceptor materials, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are particularly suitable because they have high acceptability and stable film quality against heat. In addition, radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) [3] are also preferred because they have very high electron-accepting properties, and specifically, α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], etc. can be used.

[0176] As a material with high hole injection properties, an oxide of a metal belonging to Groups 4 to 8 in the periodic table (transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide) can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among the above, molybdenum oxide is preferred because it is stable in the air, has low hygroscopicity, and is easy to handle. In addition, perylene tetracarboxylic acid derivatives such as diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), 3,4,9,10-perylene tetracarboxylic diimide (abbreviation: PTCDI), and 3,4,9,10-perylene tetracarboxyl-bis-benzimidazole (abbreviation: PTCBI), (C 60 -Ih)[5,6]fullerene (abbreviation: C 60 ), (C70-D5h)[5,6]fullerene (abbreviation: C 70), organic compounds such as phthalocyanine (abbreviation: HPc), copper phthalocyanine (abbreviation: CuPc), zinc phthalocyanine (abbreviation: ZnPc), cobalt phthalocyanine (abbreviation: CoPc), iron phthalocyanine (abbreviation: FePc), tin phthalocyanine (abbreviation: SnPc), tin oxide phthalocyanine (abbreviation: SnOPc), titanium oxide phthalocyanine (abbreviation: TiOPc), vanadium oxide phthalocyanine (abbreviation: VOPc), and metal phthalocyanines having copper, zinc, cobalt, iron, chromium, nickel, and the like, and derivatives thereof can be used. In particular, phthalocyanine-based metal complexes such as CuPc or ZnPc or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine are preferred. Among them, CuPc and ZnPc are preferred because they are inexpensive and have good characteristics. Furthermore, ZnPc has a small diffusion coefficient into silicon, which reduces the risk of affecting the semiconductor characteristics due to diffusion of metal into the semiconductor, making it particularly suitable for use in display devices that use silicon semiconductors.

[0177] In addition to the above materials, the following low molecular weight compounds are also available: 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: DNTPD), 1,3,5-tris[N Aromatic amine compounds such as -(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0178] Also, polymer compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. can be used. Alternatively, polymer compounds to which an acid has been added, such as poly(3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (abbreviation: PEDOT / PSS), polyaniline / polystyrenesulfonic acid (abbreviation: PAni / PSS), etc. can also be used.

[0179] As the material with high hole injection properties, a mixed material containing a hole transport material and the above-mentioned organic acceptor material (electron accepting material) can also be used. In this case, electrons are extracted from the hole transport material by the organic acceptor material, generating holes in the hole injection layer 111, and the holes are injected into the light emitting layer 113 via the hole transport layer 112. The hole injection layer 111 may be formed as a single layer made of a mixed material containing a hole transport material and an organic acceptor material (electron accepting material), or may be formed by laminating the hole transport material and the organic acceptor material (electron accepting material) in separate layers.

[0180] In addition, the hole transport material has a hole mobility of 1×10 at a square root of the electric field strength [V / cm] of 600. -6 cm 2 A substance having a hole mobility of / Vs or more is preferable. Note that other substances can be used as long as they have a higher hole transporting property than an electron transporting property.

[0181] As the hole transporting material, a compound having a π-electron-rich heteroaromatic ring (for example, a carbazole derivative, a furan derivative, or a thiophene derivative) and an aromatic amine (an organic compound having an aromatic amine skeleton) are preferable.

[0182] Examples of the carbazole derivative (organic compound having a carbazole ring) include bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives) and aromatic amines having a carbazolyl group.

[0183] Specific examples of the bicarbazole derivative (e.g., 3,3'-bicarbazole derivative) include 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), and 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP).

[0184] Specific examples of the aromatic amine having a carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBiF), and Name: PCBBiF), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]bis(9,9-dimethyl-9H-fluoren-2-yl)amine (abbreviation: PCBFF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-(9,9-dimethyl-9H-fluoren-2-yl)-9,9-dimethyl-9H-fluorene -4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluorene )-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluoren)-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-Dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-4-amine, 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 3-[N-(9-phenyl 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), N-(9,9-spirobi[9H-fluoren]-2-yl)-N,9-diphenylcarbazole-3-amine (abbreviation: PCASF), N-(4-biphenyl)-4-(carbazol-9-yl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), etc.

[0185] In addition to the above, examples of the carbazole derivative include 9-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]phenanthrene (abbreviation: PCPPn), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA).

[0186] Specific examples of the furan derivatives (organic compounds having a furan ring) include 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and the like.

[0187] Specific examples of the thiophene derivative (organic compound having a thiophene ring) include organic compounds having a thiophene ring, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV).

[0188] Specific examples of the aromatic amine include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP ... -phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), N-(9,9-spirobi[9H-fluoren]-2-yl )-N,N'N'-triphenyl-1,4-phenylenediamine (abbreviation: DPASF), N,N'-diphenyl-N,N'-bis(4-diphenylaminophenyl)spirobi[9H-fluorene]-2,7-diamine (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenyla amino]triphenylamine (abbreviation: m-MTDATA), N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2- d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4', 4''-Diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-( 7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl] 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N- Bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), N,N-bis(9,9-dimethyl-9H-fluorene-2- N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, and the like can be mentioned.

[0189] Other examples of the hole transport material that can be used include polymer compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. Alternatively, polymer compounds to which an acid has been added, such as poly(3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (abbreviation: PEDOT / PSS) and polyaniline / polystyrenesulfonic acid (abbreviation: PAni / PSS), etc., can also be used.

[0190] However, the hole transporting material is not limited to the above, and one or a combination of various known materials may be used as the hole transporting material.

[0191] The hole injection layers (111, 111a, 111b) can be formed using various known film formation methods, for example, a vacuum deposition method.

[0192] <Hole transport layer> The hole transport layers (112, 112a, 112b) are layers that transport holes injected from the first electrode 101 by the hole injection layers (111, 111a, 111b) to the light emitting layers (113, 113a, 113b). The hole transport layers (112, 112a, 112b) are layers that contain a hole transport material. Therefore, the hole transport materials that can be used for the hole injection layers (111, 111a, 111b) can be used for the hole transport layers (112, 112a, 112b).

[0193] In the light-emitting device according to one embodiment of the present invention, the light-emitting layer (113, 113a, 113b) can be formed using the same organic compound as that of the hole-transport layer (112, 112a, 112b). It is more preferable to use the same organic compound for the hole-transport layer (112, 112a, 112b) and the light-emitting layer (113, 113a, 113b) because holes can be efficiently transported from the hole-transport layer (112, 112a, 112b) to the light-emitting layer (113, 113a, 113b).

[0194] <Electron Block Layer> The electron blocking layer 116 is provided for the purpose of preventing electrons from passing through from the light-emitting layer 113 to the first electrode 101. A material having excellent hole transporting properties, low electron transporting properties, and a high LUMO level is suitable for the electron blocking layer 116. Among the substances listed above that can be used as the material for the hole-transporting layer 112, it is preferable to form the layer using a material having a LUMO level higher than the LUMO level of the material (at least the host material) constituting the light-emitting layer, preferably 0.30 eV or higher. Note that the electron blocking layer transports holes, and therefore can also be regarded as a part of the hole-transporting layer 112.

[0195] <Light-emitting layer> The light-emitting layers (113, 113a, 113b) are layers containing a light-emitting substance. As the light-emitting substance that can be used for the light-emitting layers (113, 113a, 113b), a substance that emits light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red can be appropriately used. When the light-emitting layer has a plurality of light-emitting layers, a structure that emits different light colors (for example, white light emission obtained by combining light-emitting colors that are complementary to each other) can be obtained by using different light-emitting substances for each light-emitting layer. When the light-emitting layer has a plurality of light-emitting layers, each light-emitting layer can be configured to emit the same color. In the case of a structure in which a plurality of light-emitting layers that emit the same light color are stacked, reliability may be improved more than in a single-layer structure. Furthermore, a stacked structure in which one light-emitting layer contains different light-emitting substances may be used.

[0196] Furthermore, the light-emitting layers (113, 113a, 113b) may contain one or more types of organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0197] In addition, when a plurality of host materials are used in the light-emitting layer (113, 113a, 113b), it is preferable to use a substance having a larger energy gap than the existing guest material and the first host material as the second host material to be added. In addition, it is preferable that the lowest singlet excitation energy level (S1 level) of the second host material is higher than the S1 level of the first host material, and the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the guest material. In addition, it is preferable that the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the first host material. With such a structure, an exciplex can be formed by two types of host materials. In addition, in order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily accepts holes (hole transporting material) and a compound that easily accepts electrons (electron transporting material). In addition, with this structure, high efficiency, low voltage, and long life can be simultaneously achieved.

[0198] As the organic compound used as the host material (including the first host material and the second host material), as long as it satisfies the conditions as a host material used in the light-emitting layer, examples of the organic compound include a hole-transporting material that can be used in the hole-transporting layer (112, 112a, 112b) described above, or an electron-transporting material that can be used in the electron-transporting layer (114, 114a, 114b) described below, and may be an exciplex composed of multiple types of organic compounds (the first host material and the second host material described above). Note that an exciplex (also called an exciplex) that forms an excited state with multiple types of organic compounds has an extremely small difference between the S1 level and the T1 level, and functions as a thermally activated delayed fluorescence (TADF) material that can convert triplet excitation energy into singlet excitation energy. As a combination of a plurality of organic compounds forming an exciplex, for example, one of them may have a π-electron deficient heteroaromatic ring and the other may have a π-electron rich heteroaromatic ring. As a combination for forming an exciplex, one of the organic compounds may be a phosphorescent material such as an iridium, rhodium, or platinum-based organometallic complex or a metal complex.

[0199] There are no particular limitations on the light-emitting substance that can be used in the light-emitting layers (113, 113a, 113b), and any light-emitting substance that converts singlet excitation energy into light emission in the visible light range, or any light-emitting substance that converts triplet excitation energy into light emission in the visible light range, can be used.

[0200] <Light-emitting material that converts singlet excitation energy into light> Examples of luminescent materials that can be used in the luminescent layers (113, 113a, 113b) and convert singlet excitation energy into luminescence include the following fluorescent materials (fluorescent luminescent materials). For example, pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives are listed. Pyrene derivatives are particularly preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophene-2-yl)-N, N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), etc.

[0201] In addition, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenyl-4,4'-stilbenediamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)phenyl]- N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'- (9-Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), and the like can be used.

[0202] In addition, N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(biphenyl-2-yl)-N-[ 4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), Rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinit (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhA FD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), 1,6BnfAP rn-03, 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, 1,6BnfAPrn-03, etc. can be used.

[0203] <Light-emitting material that converts triplet excitation energy into light> Next, examples of the light-emitting material that can be used in the light-emitting layer 113 and converts triplet excitation energy into light emission include a material that emits phosphorescence (phosphorescent material) and a TADF material that exhibits thermally activated delayed fluorescence.

[0204] A phosphorescent material is a compound that exhibits phosphorescence but does not exhibit fluorescence in a temperature range from low temperature (e.g., 77 K) to room temperature (i.e., 77 K to 313 K). The phosphorescent material preferably has a metal element with a large spin-orbit interaction, and examples of the phosphorescent material include an organometallic complex, a metal complex (platinum complex), and a rare earth metal complex. Specifically, a transition metal element is preferable, and it is particularly preferable to have a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)). Among these, it is preferable to have iridium, since it can increase the transition probability related to the direct transition between the singlet ground state and the triplet excited state.

[0205] <Phosphorescent material (450nm to 570nm: blue or green)> Examples of phosphorescent substances that exhibit blue or green light and have an emission spectrum with a peak wavelength of 450 nm or more and 570 nm or less include the following substances.

[0206] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato] Organometallic complexes with a 4H-triazole ring, such as iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz)3]), tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1- Organometallic complexes containing a 1H-triazole ring, such as methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(II I) (abbreviation: [Ir(dmpimpt-Me)3]), organometallic complexes with an imidazole ring, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C2']iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C2']iridium(III) picolinate (abbreviation: FIrpic), and bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C2']iridium(III) picolinate (abbreviation: FIrpic). 2’}Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’] Examples include organometallic complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviation: FIr(acac)).

[0207] <Phosphorescent material (495nm to 590nm: green or yellow)> Examples of phosphorescent substances that exhibit green or yellow light and have an emission spectrum with a peak wavelength of 495 nm or more and 590 nm or less include the following substances.

[0208] For example, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm Organometallic iridium compounds having a pyrimidine ring, such as (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]). iridium complexes with pyrazine rings, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinate)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]); tris(2-phenylpyrazinate-N,C 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’)iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl -κN)phenyl-κC], [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) Iridium(III) (abbreviation: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC] Organometallic iridium complexes with a pyridine ring, such as [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mdppy)), and bis(2,4-diphenyl-1,3-oxazolato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinato-N,C 2’}Iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolato-N,C 2’ ) iridium(III) acetylacetonate (abbreviation: [Ir(bt)2(acac)]), as well as rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]).

[0209] <Phosphorescent material (570nm to 750nm: yellow or red)> Examples of phosphorescent substances that exhibit yellow or red light and have an emission spectrum with a peak wavelength of 570 nm or more and 750 nm or less include the following substances.

[0210] For example, pyrimidinate such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]). Organometallic complexes containing an imidine ring, (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κN)phenyl-κC) 2O,O')iridium(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-dmCP)2(dpm)]), bis{2-[5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]-4,6-dimethylphenyl-κC}(2,2',6,6'-tetramethyl-3,5-heptanedionato-κ2O,O')iridium(III) (abbreviation: [Ir(dmdppr-dmp)2(dpm)]), (acetylacetonato)bis(2-methyl-3-phenylquinoxalinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(mpq)2(acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C 2’ Organometallic complexes with pyrazine rings such as (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(dpq)2(acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), and bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC] (2,4-pentanedionato-κ 2Examples of such complexes include organometallic complexes having a pyridine ring, such as (O,O')iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]), platinum complexes, such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: [PtOEP]), and rare earth metal complexes, such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]).

[0211] ≪TADF material≫ The following materials can be used as TADF materials. TADF materials are materials in which the difference between the S1 level and the T1 level is small (preferably 0.20 eV or less), the triplet excited state can be upconverted to the singlet excited state by a small amount of thermal energy (reverse intersystem crossing), and the material efficiently emits light (fluorescence) from the singlet excited state. Conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited energy level and the singlet excited energy level of 0.00 eV or more and 0.20 eV or less, preferably 0.00 eV or more and 0.10 eV or less. The delayed fluorescence in TADF materials refers to light emission that has a spectrum similar to that of normal fluorescence but has a significantly long lifespan. The lifespan is 1×10 -6 seconds or 1×10 -3 More than seconds.

[0212] Note that the TADF material can also be used as an electron transporting material, a hole transporting material, or a host material.

[0213] Examples of TADF materials include fullerene and its derivatives, acridine derivatives such as proflavine, eosin, etc. Also included are metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2OEP).

[0214] [ka]

[0215] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxy) 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9, 9-Dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9'-phenyl-3,3'- Heteroaromatic compounds having a π-electron rich heteroaromatic compound and a π-electron deficient heteroaromatic compound, such as 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), may also be used.

[0216] In addition, a substance in which a π-electron rich heteroaromatic compound and a π-electron deficient heteroaromatic compound are directly bonded is particularly preferable because the donor property of the π-electron rich heteroaromatic compound and the acceptor property of the π-electron deficient heteroaromatic compound are both strong, and the energy difference between the singlet excited state and the triplet excited state is small. In addition, a TADF material (TADF100) in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used as the TADF material. Such a TADF material has a short emission lifetime (excitation lifetime), so that the efficiency decrease in the high brightness region of the light-emitting device can be suppressed.

[0217] [ka]

[0218] In addition to the above, examples of materials capable of converting triplet excitation energy into luminescence include nanostructures of transition metal compounds having a perovskite structure. In particular, nanostructures of metal halide perovskites are preferred. As the nanostructures, nanoparticles and nanorods are preferred.

[0219] In the light-emitting layers (113, 113a, 113b, 113c), one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) may be selected and used as the organic compound (host material, etc.) used in combination with the above-mentioned light-emitting substance (guest material).

[0220] <Fluorescent host material> When the light-emitting substance used in the light-emitting layers (113, 113a, 113b, 113c) is a fluorescent light-emitting substance, it is preferable to use an organic compound (host material) that has a high energy level in a singlet excited state and a low energy level in a triplet excited state, or an organic compound with a high fluorescence quantum yield. Therefore, as long as the organic compound satisfies such conditions, a hole-transporting material (described above) and an electron-transporting material (described below) shown in this embodiment mode can be used.

[0221] Although some of the examples overlap with those described above, examples of the organic compound (host material) from the viewpoint of a preferable combination with a light-emitting substance (fluorescent light-emitting substance) include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0222] Specific examples of organic compounds (host materials) that are preferably used in combination with fluorescent substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenylanthracene (abbreviation: N,N-diphenylanthracene), and N,N-diphenylanthracene (abbreviation: N,N-diphenylanthracene). N-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA) , 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl] Benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4'-(9-phenyl-9H-fluoren-9-yl)biphenyl-4-yl]anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 2,9-di(1-naphthyl)-10-phenylanthracene (abbreviation: 2αN-αNPhA), 9-(1-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: αN-mαNPAnth), 9-(2-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: βN-mαNPAnth), 9-(1-naphthyl)-10-[4-(1-naphthyl)phenyl]anthracene (abbreviation: αN-αNPAnth), 9-(2-naphthyl)-10-[4-(2-naphthyl)phenyl] Anthracene (abbreviation: βN-βNPAnth), 2-(1-naphthyl)-9-(2-naphthyl)-10-phenylanthracene (abbreviation: 2αN-βNPhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtB ImPBPhA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene, etc.

[0223] <Phosphorescent host material> Furthermore, when the light-emitting substance used in the light-emitting layers (113, 113a, 113b, 113c) is a phosphorescent light-emitting substance, an organic compound having a triplet excitation energy larger than the triplet excitation energy (energy difference between the ground state and the triplet excited state) of the light-emitting substance may be selected as the organic compound (host material) to be combined. Note that when multiple organic compounds (e.g., a first host material and a second host material (or assist material)) are used in combination with the light-emitting substance to form an exciplex, it is preferable to mix these multiple organic compounds with the phosphorescent light-emitting substance.

[0224] With this structure, it is possible to efficiently obtain light emission using ExTET (Exciplex-Triplet Energy Transfer), which is an energy transfer from an exciplex to a light-emitting substance. As a combination of multiple organic compounds, it is preferable to use one that easily forms an exciplex, and it is particularly preferable to combine a compound that easily receives holes (hole transport material) with a compound that easily receives electrons (electron transport material).

[0225] Although some of the organic compounds (host materials, assist materials) may be used in combination with the light-emitting substance (phosphorescent light-emitting substance), examples of the organic compounds include aromatic amines (organic compounds having an aromatic amine skeleton), carbazole derivatives (organic compounds having a carbazole ring), dibenzothiophene derivatives (organic compounds having a dibenzothiophene ring), dibenzofuran derivatives (organic compounds having a dibenzofuran ring), oxadiazole derivatives (organic compounds having an oxadiazole ring), triazole derivatives (organic compounds having a triazole ring), benzimidazole derivatives (benzo Examples of suitable organic compounds include organic compounds having an imidazole ring, quinoxaline derivatives (organic compounds having a quinoxaline ring), dibenzoquinoxaline derivatives (organic compounds having a dibenzoquinoxaline ring), pyrimidine derivatives (organic compounds having a pyrimidine ring), triazine derivatives (organic compounds having a triazine ring), pyridine derivatives (organic compounds having a pyridine ring), bipyridine derivatives (organic compounds having a bipyridine ring), phenanthroline derivatives (organic compounds having a phenanthroline ring), phlodiazine derivatives (organic compounds having a phlodiazine ring), zinc- and aluminum-based metal complexes, and the like.

[0226] Among the organic compounds, specific examples of the aromatic amine and carbazole derivative, which are organic compounds having a high hole-transporting property, are the same as the specific examples of the hole-transporting material described above, and any of these are preferable as the host material.

[0227] Among the above organic compounds, specific examples of the dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole transport properties, include 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), DBT3P-II, 2,8-dipheny Examples of the dibenzothiophene include 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and 4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II), all of which are preferable as the host material.

[0228] Other examples of preferred host materials include metal complexes having oxazole- or thiazole-based ligands, such as bis[2-(2-benzoxazolyl)phenolate]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolate]zinc(II) (abbreviation: ZnBTZ).

[0229] Specific examples of the organic compounds having high electron transport properties among the above organic compounds include oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, and phenanthroline derivatives. Examples of the organic compounds having high electron transport properties include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-(phenylene)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-9), 9-(phenylene)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-1), 9-(phenylene)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-1), 9-(phenylene)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-2), 9-(phenylene)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-1 ... -[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), Organic compounds containing heteroaromatic rings with polyazole rings, such as 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and compounds containing heteroaromatic rings with phenanthroline rings, such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), and 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P). Organic compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), and other organic compounds containing a heteroaromatic ring having a dibenzoquinoxaline ring, all of which are preferable as the host material. ,

[0230] Among the above organic compounds, specific examples of organic compounds having high electron transport properties, such as pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, and pyridazine derivatives), triazine derivatives, and furodiazine derivatives, include 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II). 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (35DCzPPy), 1,3 ,5-Tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d ]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 11-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 11-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 12-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 12PCCzPnfpr), 9-[3'-(9 -phenyl-9H-carbazol-3-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmPCBPNfpr), 9-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9PCCzNfpr), 10-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 10PCCzNfpr), 9-[3'-(6-phenylbenzo[b]naphtho [1,2-d]furan-8-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mBnfBPNfpr), 9-{3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), 9-[3'-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr-02), 9-[3-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mPCCzPNfpr), 9-[3'-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine, 11-[3'-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9, 9'-Spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-furan Examples of suitable organic compounds include organic compounds containing heteroaromatic rings having a diazine ring, such as phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), and 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), all of which are suitable as host materials.

[0231] Among the above organic compounds, specific examples of metal complexes, which are organic compounds with high electron transport properties, include zinc- or aluminum-based metal complexes such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq), as well as metal complexes having a quinoline ring or a benzoquinoline ring, all of which are preferable as the host material.

[0232] Other preferred host materials include polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy).

[0233] Furthermore, bipolar organic compounds having high hole transport properties and high electron transport properties, such as 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviation: PCCzQz), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[ Organic compounds having a diazine ring, such as 2,1-b]carbazole (abbreviation: mINc(II)PTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), and 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), can also be used as the host material.

[0234] <Hole blocking layer> The hole blocking layer 117 is provided for the purpose of preventing holes from passing through from the light-emitting layer 113 to the second electrode 102. A material having excellent electron transport properties, low hole transport properties, and a deep HOMO level is suitable for the hole blocking layer 117. Among the materials that can be used as the material of the electron transport layer 114 described later, a material having a HOMO level lower than the HOMO level of the material (at least the host material) constituting the light-emitting layer, preferably 0.30 eV or more lower, is preferably used for the hole blocking layer 117. Note that the hole blocking layer can be regarded as a part of the electron transport layer 114 because it transports electrons.

[0235] <Electron transport layer> The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 and the charge generation layers (106, 106a, 106b) by the electron injection layers (115, 115a, 115b) described later to the light-emitting layers (113, 113a, 113b). Note that in the light-emitting device that is one embodiment of the present invention, the electron transport layer has a stacked structure, so that the heat resistance can be improved. In addition, the electron transport material used for the electron transport layers (114, 114a, 114b) has an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600. -6 cm 2 A substance having an electron mobility of 100 / Vs or more is preferable. Note that other substances can be used as long as they have a higher electron transporting property than holes. The electron transporting layer (114, 114a, 114b) can function as a single layer, but may have a stacked structure of two or more layers. Note that the above mixed materials have heat resistance, so that the effect of a thermal process on device characteristics can be suppressed by performing a photolithography process on an electron transporting layer using the mixed materials.

[0236] ≪Electron transport material≫ As the electron transporting material that can be used for the electron transport layer (114, 114a, 114b), an organic compound with high electron transporting properties can be used, for example, a heteroaromatic compound. The heteroaromatic compound is a cyclic compound containing at least two different elements in a ring. The ring structure includes a three-membered ring, a four-membered ring, a five-membered ring, a six-membered ring, etc., and a five-membered ring or a six-membered ring is particularly preferred, and the element contained is preferably a heteroaromatic compound containing one or more of nitrogen, oxygen, or sulfur in addition to carbon. In particular, a heteroaromatic compound containing nitrogen (nitrogen-containing heteroaromatic compound) is preferred, and it is preferable to use a material with high electron transporting properties (electron transporting material) such as a nitrogen-containing heteroaromatic compound or a π-electron-deficient heteroaromatic compound containing the same.

[0237] The electron transport material may be a material different from the material used in the light-emitting layer. Not all of the excitons generated by the recombination of carriers in the light-emitting layer can contribute to light emission, and they may diffuse to layers adjacent to or in the vicinity of the light-emitting layer. In order to avoid this phenomenon, it is preferable that the energy level (lowest singlet excitation level or lowest triplet excitation level) of the material used in the layer adjacent to or in the vicinity of the light-emitting layer is higher than that of the material used in the light-emitting layer. Therefore, by using a material different from the material used in the light-emitting layer as the electron transport material, a highly efficient device can be obtained.

[0238] A heteroaromatic compound is an organic compound that contains at least one heteroaromatic ring.

[0239] The heteroaromatic ring has any one of a pyridine ring, a diazine ring, a triazine ring, a polyazole ring, an oxazole ring, and a thiazole ring. The heteroaromatic ring having a diazine ring includes a heteroaromatic ring having a pyrimidine ring, a pyrazine ring, and a pyridazine ring. The heteroaromatic ring having a polyazole ring includes a heteroaromatic ring having an imidazole ring, a triazole ring, and an oxadiazole ring.

[0240] The heteroaromatic ring also includes a condensed heteroaromatic ring having a condensed ring structure, such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phlodiazine ring, or a benzimidazole ring.

[0241] Incidentally, among heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a five-membered ring structure include heteroaromatic compounds having an imidazole ring, heteroaromatic compounds having a triazole ring, heteroaromatic compounds having an oxazole ring, heteroaromatic compounds having an oxadiazole ring, heteroaromatic compounds having a thiazole ring, and heteroaromatic compounds having a benzimidazole ring.

[0242] Furthermore, for example, among heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a 6-membered ring structure include heteroaromatic compounds having a heteroaromatic ring such as a pyridine ring, a diazine ring (including a pyrimidine ring, a pyrazine ring, and a pyridazine ring), a triazine ring, and a polyazole ring. Included in the heteroaromatic compounds having a structure in which pyridine rings are linked are heteroaromatic compounds having a bipyridine structure and heteroaromatic compounds having a terpyridine structure.

[0243] Further, examples of heteroaromatic compounds having a fused ring structure partially including the above-mentioned 6-membered ring structure include heteroaromatic compounds having a fused heteroaromatic ring such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, a phlodiazine ring (including a structure in which an aromatic ring is fused to the furan ring of a phlodiazine ring), and a benzimidazole ring.

[0244] Specific examples of the heteroaromatic compound having a five-membered ring structure (polyazole ring (including imidazole ring, triazole ring, and oxadiazole ring), oxazole ring, thiazole ring, benzimidazole ring, etc.) include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-furan (abbreviation: FUJI ...1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4 phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and the like.

[0245] Specific examples of the heteroaromatic compound having a 6-membered ring structure (including a heteroaromatic ring having a pyridine ring, a diazine ring, a triazine ring, etc.) include heteroaromatic compounds having a pyridine ring such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB); ,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine mTpBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (BP-SFTzn), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (PCDBfTzn), 2-(biphenyl-3 heteroaromatic compounds containing heteroaromatic rings having a triazine ring, such as 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), mFBPTzn, 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-Bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2P Pm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalen-2-yl)-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8BP-4mDBtPBfpm, 9mDBtBPN fpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl and heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring, such as 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm). The aromatic compounds containing a heteroaromatic ring include heteroaromatic compounds having a condensed heteroaromatic ring.

[0246] Other examples include 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mB heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring, such as 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tz), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), and the like.

[0247] Specific examples of the heteroaromatic compound having a fused ring structure partially including a 6-membered ring structure (heteroaromatic compound having a fused ring structure) include bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenylene)bis(1,2-phenylene)-2,2'-(1,3 ... mPPhen2P), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPD and heteroaromatic compounds having a quinoxaline ring, such as 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-III), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), and 2mpPCBPDBq.

[0248] In addition to the heteroaromatic compounds described above, the electron transport layer (114, 114a, 114b) may include the following metal complexes: metal complexes having a quinoline ring or a benzoquinoline ring, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), Almq3, 8-quinolinolato-lithium (abbreviation: Liq), BeBq2, bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq), and metal complexes having an oxazole ring or a thiazole ring, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

[0249] In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used as electron transport materials.

[0250] In addition, the electron transport layer (114, 114a, 114b) may be not only a single layer, but also a laminate structure of two or more layers made of the above-mentioned substances.

[0251] <Electron injection layer> The electron injection layers (115, 115a, 115b) are layers containing a substance with high electron injection properties. The electron injection layers (115, 115a, 115b) are layers for increasing the efficiency of electron injection from the second electrode 102, and it is preferable to use a material having a small difference (0.50 eV or less) between the work function value of the material used for the second electrode 102 and the LUMO level value of the material used for the electron injection layers (115, 115a, 115b). Therefore, the electron injection layer 115 may contain any of the following: lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-quinolinolato-lithium (abbreviation: Liq), 2-(2-pyridyl)phenolatolithium (abbreviation: LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviation: LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviation: LiPPP), lithium oxide (LiO x), cesium carbonate, or other alkali metals, alkaline earth metals, or compounds thereof can be used. Rare earth metals or rare earth metal compounds, such as erbium fluoride (ErF3) and ytterbium (Yb), can also be used. 1-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine (abbreviation: 2hppSF), 1,1'-(9,9'-spirobi[9H-fluorene]-2,7-diyl)bis( ... Compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton, such as 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: 2,7hpp2SF) and 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: hpp2Py), can also be used. The electron injection layer (115, 115a, 115b) may be formed by mixing a plurality of the above materials, or may be formed by stacking a plurality of the above materials. The electron injection layer (115, 115a, 115b) may also be formed by using an electride. Examples of the electride include a substance in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum. The substances constituting the above-mentioned electron transport layer (114, 114a, 114b) can also be used.

[0252] In addition, a mixed material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer (115, 115a, 115b). Such a mixed material has excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons, and specifically, for example, the above-mentioned electron transport material (metal complex, heteroaromatic compound, etc.) used for the electron transport layer (114, 114a, 114b) can be used. The electron donor may be any substance that exhibits electron donating properties to the organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, and examples of the electron donor include lithium, cesium, magnesium, calcium, erbium, and ytterbium. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, and examples of the oxide include lithium oxide, calcium oxide, and barium oxide. In addition, a Lewis base such as magnesium oxide can also be used. In addition, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used. Moreover, a plurality of these materials may be laminated.

[0253] Alternatively, the electron injection layer (115, 115a, 115b) may be made of a mixed material made of an organic compound and a metal. The organic compound used here preferably has a LUMO level of -3.60 eV or more and -2.30 eV or less. In addition, a material having an unshared electron pair is preferable.

[0254] Therefore, as the organic compound used in the above mixed material, a mixed material obtained by mixing a heteroaromatic compound with a metal, which is described above as being usable in the electron transport layer, may be used. As the heteroaromatic compound, a material having an unshared electron pair, such as a heteroaromatic compound having a 5-membered ring structure (imidazole ring, triazole ring, oxazole ring, oxadiazole ring, thiazole ring, benzimidazole ring, etc.), a heteroaromatic compound having a 6-membered ring structure (pyridine ring, diazine ring (including pyrimidine ring, pyrazine ring, pyridazine ring, etc.), triazine ring, bipyridine ring, terpyridine ring, etc.), or a heteroaromatic compound having a condensed ring structure (quinoline ring, benzoquinoline ring, quinoxaline ring, dibenzoquinoxaline ring, phenanthroline ring, etc.) that partially includes a 6-membered ring structure, is preferable. Specific materials have been described above, so a description thereof will be omitted here.

[0255] As the metal used in the above mixed material, it is preferable to use a transition metal belonging to Group 5, Group 7, Group 9 or Group 11 in the periodic table and a material belonging to Group 13, such as Ag, Cu, Al, or In. In this case, the organic compound forms a half occupied molecular orbital (SOMO) with the transition metal.

[0256] For example, when the light obtained from the light-emitting layer 113b is amplified, the optical distance between the second electrode 102 and the light-emitting layer 113b is preferably less than ¼ of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, the thickness can be adjusted by changing the thickness of the electron-transporting layer 114b or the electron-injecting layer 115b.

[0257] In addition, as in the light-emitting device shown in Figure 13 (E), by providing a charge generation layer 106 between two EL layers (103a, 103b), a structure in which multiple EL layers are stacked between a pair of electrodes (also called a tandem structure) can be formed.

[0258] <Charge generation layer> The charge generation layer 106 has a function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layer 106 may be a structure in which an electron acceptor is added to a hole transporting material (also called a P-type layer), or a structure in which an electron donor is added to an electron transporting material (also called an electron injection buffer layer). In addition, both of these structures may be stacked. Furthermore, an electron relay layer may be provided between the P-type layer and the electron injection buffer layer. By forming the charge generation layer 106 using the above-mentioned material, it is possible to suppress an increase in driving voltage when EL layers are stacked.

[0259] In the case where the charge generation layer 106 has a structure (P-type layer) in which an electron acceptor is added to a hole transporting material that is an organic compound, the material shown in this embodiment mode can be used as the hole transporting material. Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ) and chloranil. Examples of the oxide of a metal that belongs to Groups 4 to 8 of the periodic table can also be used. Specific examples of the oxide include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. Note that the above-mentioned acceptor material may also be used. In addition, a mixed film obtained by mixing materials constituting the P-type layer may be used, or single films containing each material may be stacked.

[0260] In the case where the charge generation layer 106 has a structure in which an electron donor is added to an electron transporting material (electron injection buffer layer), the material shown in this embodiment can be used as the electron transporting material. In addition, as the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, or a metal belonging to Group 2 or Group 13 in the periodic table, and an oxide or carbonate thereof can be used. Specifically, it is preferable to use lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (Li2O), cesium carbonate, or the like. In addition, an alkali metal compound such as Liq may be used. In addition, an organic compound such as tetrathianaphthacene may be used as the electron donor. In addition, organic compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton, such as 2hppSF, 2,7hpp2SF, and hpp2Py, may be used as electron donors. When using these organic compounds as electron donors, it is preferable to use organic compounds containing a heteroaromatic ring having a phenanthroline ring, such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), and 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), as the electron transport material to be combined, since the driving voltage of the light-emitting device can be reduced.

[0261] In the case where an electron relay layer is provided between the P-type layer and the electron injection buffer layer in the charge generation layer 106, the electron relay layer contains at least a substance having electron transport properties, and has a function of preventing an interaction between the electron injection buffer layer and the P-type layer and smoothly transferring electrons. The LUMO level of the substance having electron transport properties contained in the electron relay layer is preferably between the LUMO level of the acceptor substance in the P-type layer and the LUMO level of the substance having electron transport properties contained in the electron transport layer in contact with the charge generation layer 106. The specific energy level of the LUMO level of the substance having electron transport properties used in the electron relay layer is -5.00 eV or more, preferably -5.00 eV or more and -3.00 eV or less. Note that, as the substance having electron transport properties used in the electron relay layer, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0262] From the viewpoint of light extraction efficiency, the charge generation layer 106 preferably has a visible light transmitting property (specifically, the visible light transmittance of the charge generation layer 106 is 40% or more). The charge generation layer 106 functions even if it has a lower electrical conductivity than the first electrode 101 and the second electrode 102.

[0263] Although FIG. 13E shows a structure in which the EL layer 103 has two stacked layers, a stacked structure of three or more EL layers may be used by providing a charge generating layer between different EL layers.

[0264] <Cap layer> Although not shown in Figures 13(A) to 13(E), a capping layer may be provided on the second electrode 102 of the light-emitting device. For example, a material with a high refractive index can be used for the capping layer. By providing the capping layer on the second electrode 102, the extraction efficiency of light emitted from the second electrode 102 can be improved.

[0265] Specific examples of materials that can be used for the capping layer include 5,5'-diphenyl-2,2'-di-5H-[1]benzothieno[3,2-c]carbazole (abbreviation: BisBTc) and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II).

[0266] <Substrate> The light-emitting device shown in this embodiment mode can be formed on various substrates. The type of substrate is not limited to a specific one. Examples of the substrate include a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, a tungsten substrate, a substrate having tungsten foil, a flexible substrate, a laminated film, a paper containing a fibrous material, or a base film.

[0267] Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, soda lime glass, etc. Examples of flexible substrates, laminated films, base films, etc. include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aramid, epoxy resins, inorganic deposition films, and papers.

[0268] In addition, a gas phase method such as a vapor deposition method, a spin coating method, and a liquid phase method such as an inkjet method can be used to manufacture the light-emitting device shown in this embodiment. When a vapor deposition method is used, a physical vapor deposition method (PVD method) such as a sputtering method, an ion plating method, an ion beam deposition method, a molecular beam deposition method, or a vacuum deposition method, a chemical vapor deposition method (CVD method), or the like can be used. In particular, layers having various functions included in the EL layer of the light-emitting device (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) can be formed by a vapor deposition method (vacuum deposition method, etc.), a coating method (dip coating method, die coating method, bar coating method, spin coating method, spray coating method, or the like), a printing method (inkjet method, screen (screen printing) method, offset (lithographic printing) method, flexo (relief printing) method, gravure method, microcontact method, or the like), or the like.

[0269] In addition, when applying a film formation method such as the coating method or printing method, it is possible to use a high molecular compound (oligomer, dendrimer, polymer, etc.), a medium molecular compound (a compound in the intermediate range between a low molecular weight and a high molecular weight: a molecular weight of 400 to 4000), an inorganic compound (quantum dot material, etc.), etc. In addition, as the quantum dot material, it is possible to use a colloidal quantum dot material, an alloy type quantum dot material, a core-shell type quantum dot material, a core type quantum dot material, etc.

[0270] The layers constituting the EL layer 103 of the light-emitting device described in this embodiment (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115) are not limited to the materials described in this embodiment, and other materials can be used in combination as long as they fulfill the functions of each layer.

[0271] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0272] (Embodiment 4) In this embodiment, a display device of one embodiment of the present invention will be described with reference to FIGS.

[0273] The display device of the present embodiment can be a high-definition display device. Therefore, the display device of the present embodiment can be used for, for example, a display unit of a wristwatch-type or bracelet-type information terminal (wearable device), a VR device such as a head-mounted display (HMD), and a head-mounted wearable device such as a glasses-type AR device.

[0274] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0275] [Display module] 14A shows a perspective view of a display module 280. The display module 280 includes a display device 100A and an FPC 290.

[0276] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 described later can be viewed.

[0277] 14(B) shows a perspective view that typically illustrates the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to an FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 that is composed of a plurality of wirings.

[0278] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of Fig. 14(B). The pixel 284a can be applied with various configurations described in the above embodiment. Fig. 14(B) shows an example of a case where the pixel 284a has a configuration similar to that of the pixel 110 shown in Fig. 1(A).

[0279] The pixel circuit section 283 has a plurality of pixel circuits 283a that are periodically arranged.

[0280] One pixel circuit 283a is a circuit that controls the driving of multiple elements included in one pixel 284a. One pixel circuit 283a can be configured to have three circuits that control the light emission of one light-emitting device. For example, the pixel circuit 283a can be configured to have at least one selection transistor, one current control transistor (drive transistor), and a capacitance for one light-emitting device. At this time, a gate signal is input to the gate of the selection transistor, and a source signal is input to the source. This realizes an active matrix display device.

[0281] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0282] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. In addition, an IC may be mounted on the FPC 290.

[0283] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are provided overlappingly under the pixel section 284, so that the aperture ratio (effective display area ratio) of the display section 281 can be extremely high. For example, the aperture ratio of the display section 281 can be set to 40% or more and less than 100%, preferably 50% or more and 95% or less, and more preferably 60% or more and 95% or less. In addition, the pixels 284a can be arranged at an extremely high density, so that the resolution of the display section 281 can be extremely high. For example, it is preferable that the pixels 284a are arranged in the display section 281 at a resolution of 2000 ppi or more, preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 6000 ppi or more, and 20000 ppi or less, or 30000 ppi or less.

[0284] Such a display module 280 is extremely high-definition and can be suitably used in VR devices such as HMDs or glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through a lens, the display module 280 has an extremely high-definition display unit 281, so that even if the display unit is enlarged with a lens, pixels are not visible, and a highly immersive display can be performed. In addition, the display module 280 is not limited to this, and can be suitably used in electronic devices having a relatively small display unit. For example, it can be suitably used in the display unit of a wearable electronic device such as a wristwatch.

[0285] [Display device 100B] The display device 100B shown in FIG. 15 includes a substrate 301, a light emitting device 10R, a light emitting device 10G, a light emitting device 10B, a light emitting device 10X, and a transistor 310.

[0286] Subpixel 50R shown in FIG. 14B has light-emitting device 10R, subpixel 50G has light-emitting device 10G, subpixel 50B has light-emitting device 10B, and subpixel 50X has light-emitting device 10X.

[0287] 14A and 14B. The stacked structure from the substrate 301 to the insulating layer 255c corresponds to the layer 121 including the transistor in the first embodiment.

[0288] The transistor 310 has a channel formation region in a substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities, and functions as one of a source and a drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0289] In addition, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0290] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0291] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 located therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0292] The conductive layer 241 is provided over the insulating layer 261 and is embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0293] Note that at least one of the conductive layers included in the layer 121 including a transistor is preferably provided with a conductive layer surrounding the outside of the display portion 281 (or the pixel portion 284). The conductive layer can also be called a guard ring. By providing the conductive layer, it is possible to prevent elements such as transistors and light-emitting devices from being damaged by a high voltage applied to these elements due to charging caused by a process using ESD (electrostatic discharge) or plasma.

[0294] An insulating layer 255a is provided covering the capacitor 240, an insulating layer 255b is provided on the insulating layer 255a, and an insulating layer 255c is provided on the insulating layer 255b. The light emitting devices 10R, 10G, 10B, and 10X are provided on the insulating layer 255c.

[0295] The anodes of the light emitting devices 10R, 10G, 10B, and 10X are electrically connected to one of the source and drain of the transistor 310 via a plug 256 embedded in the insulating layer 243, the insulating layer 255a, the insulating layer 255b, and the insulating layer 255c, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. The height of the surface of the insulating layer 255c in contact with the anode and the height of the surface of the plug 256 in contact with the anode are the same or approximately the same. Various conductive materials can be used for the plug.

[0296] In addition, a protective layer 122 is provided on the light-emitting devices 10R, 10G, 10B, and 10X. A substrate 124 is attached to the protective layer 122 via a resin layer 123. For details of the components from the light-emitting devices to the substrate 124, refer to Embodiment 1. The substrate 124 corresponds to the substrate 292 in FIG. 14(A).

[0297] At least one of an insulating film, a semiconductor film, and a conductive film can be used as the protective layer 122. The protective layer 122 having an inorganic film can prevent oxidation of the cathode, suppress impurities (such as moisture and oxygen) from entering the light-emitting device, and suppress deterioration of the light-emitting device, thereby improving the reliability of the display device.

[0298] For example, an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used for the protective layer 122. Specific examples of these inorganic insulating films will be given in the description of the insulating layer 125. In particular, the protective layer 122 preferably has an insulating nitride film or an insulating nitride oxide film, and more preferably has a nitride insulating film.

[0299] For the resin layer 123, various curing adhesives such as a photo-curing adhesive such as an ultraviolet curing adhesive, a reaction curing adhesive, a heat curing adhesive, and an anaerobic adhesive can be used. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenol resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability such as epoxy resin is preferable. A two-liquid mixed resin may also be used. An adhesive sheet or the like may also be used.

[0300] The substrate 124 can be made of glass, quartz, ceramics, sapphire, resin, metal, alloy, semiconductor, or the like. A material that transmits light is used for the substrate on the side from which light from the light-emitting device is extracted. If a flexible material is used, the flexibility of the display device can be increased. A polarizing plate or the like may also be used. In this way, various materials can be used for the substrate.

[0301] Furthermore, the substrate 124 may be made of polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. The substrate 124 may be made of glass having a thickness sufficient to provide flexibility.

[0302] An inorganic insulating film is preferably used as the insulating layer 125. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. Alternatively, a hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may be used.

[0303] The structure of the transistor included in the display device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. In addition, either a top-gate type or a bottom-gate type transistor may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0304] The crystallinity of a semiconductor material used in a transistor is not particularly limited, and any of an amorphous semiconductor, a single crystalline semiconductor, and a semiconductor having crystallinity other than a single crystal (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a single crystalline semiconductor or a semiconductor having crystallinity is preferable because it can suppress deterioration of transistor characteristics.

[0305] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). That is, the display device of this embodiment preferably uses a transistor in which a channel formation region is formed using a metal oxide (hereinafter referred to as an OS transistor).

[0306] Examples of crystalline oxide semiconductors include c-axis-aligned crystalline (CAAC)-OS and nanocrystalline (nc)-OS.

[0307] Alternatively, a transistor using silicon in a channel formation region (Si transistor) may be used. Examples of silicon include single crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, a transistor having low temperature polysilicon (LTPS (Low Temperature Poly Silicon)) in a semiconductor layer (hereinafter, also referred to as an LTPS transistor) may be used. An LTPS transistor has high field effect mobility and good frequency characteristics.

[0308] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (such as source driver circuits) can be built on the same substrate as the display unit, simplifying the external circuits mounted on the display device and reducing component and mounting costs.

[0309] An OS transistor has a much higher field-effect mobility than a transistor using amorphous silicon. In addition, the OS transistor has a significantly smaller source-drain leakage current in an off state (hereinafter also referred to as off current), and can hold charge accumulated in a capacitor connected in series with the transistor for a long period of time. In addition, the use of an OS transistor can reduce the power consumption of a display device.

[0310] Furthermore, in order to increase the emission luminance of a light-emitting device included in a pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of a drive transistor included in the pixel circuit. Since an OS transistor has a higher withstand voltage between the source and drain compared to a Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using an OS transistor as the drive transistor included in a pixel circuit, it is possible to increase the amount of current flowing through the light-emitting device and increase the emission luminance of the light-emitting device.

[0311] Furthermore, when the transistor operates in the saturation region, the OS transistor can reduce the change in source-drain current in response to a change in gate-source voltage compared to a Si transistor. Therefore, by using an OS transistor as a driving transistor included in a pixel circuit, the current flowing between the source and drain can be precisely determined by changing the gate-source voltage, and the amount of current flowing to the light-emitting device can be controlled. This allows the pixel circuit to have a larger gradation.

[0312] Furthermore, in terms of the saturation characteristics of the current that flows when the transistor operates in the saturation region, the OS transistor can pass a more stable current (saturation current) than a Si transistor, even when the source-drain voltage gradually increases. Therefore, by using an OS transistor as a drive transistor, for example, a stable current can be passed through a light-emitting device even when the current-voltage characteristics of the light-emitting device vary. In other words, when the OS transistor operates in the saturation region, the source-drain current hardly changes even when the source-drain voltage is increased, so that the light emission luminance of the light-emitting device can be stabilized.

[0313] As described above, by using an OS transistor for the driving transistor included in the pixel circuit, it is possible to achieve "suppression of black floating," "increase in light emission luminance," "multiple gradations," and "suppression of variation in light-emitting devices."

[0314] The semiconductor layer preferably contains, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0315] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also referred to as IAZO). Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also referred to as IAGZO).

[0316] When the semiconductor layer is an In-M-Zn oxide, the atomic ratio of In in the In-M-Zn oxide is preferably equal to or greater than the atomic ratio of M. The atomic ratio of metal elements in such an In-M-Zn oxide may be In:M:Zn=1:1:1 or a composition thereabout, In:M:Zn=1:1:1.2 or a composition thereabout, In:M:Zn=1:3:2 or a composition thereabout, In:M:Zn=1:3:4 or a composition thereabout, In:M:Zn=2:1:3 or a composition thereabout, In:M:Zn=3:1:2 or a composition thereabout, In:M:Zn=4:2:3 or a composition thereabout, or a composition in the vicinity thereof, In:M:Zn=4:2:4.1 or a composition in the vicinity thereof, In:M:Zn=5:1:3 or a composition in the vicinity thereof, In:M:Zn=5:1:6 or a composition in the vicinity thereof, In:M:Zn=5:1:7 or a composition in the vicinity thereof, In:M:Zn=5:1:8 or a composition in the vicinity thereof, In:M:Zn=6:1:6 or a composition in the vicinity thereof, In:M:Zn=5:2:5 or a composition in the vicinity thereof, etc. Note that a composition in the vicinity thereof includes a range of ±30% of the desired atomic ratio.

[0317] For example, when describing a composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabout, it includes cases where, when In is 4, Ga is 1 to 3 and Zn is 2 to 4. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabout, it includes cases where, when In is 5, Ga is greater than 0.1 and less than 2 and Zn is greater than 5 and less than 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabout, it includes cases where, when In is 1, Ga is greater than 0.1 and less than 2 and Zn is greater than 0.1 and less than 2.

[0318] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0319] (Embodiment 5) In this embodiment, electronic devices of one embodiment of the present invention will be described with reference to FIGS.

[0320] The electronic devices of this embodiment include the display device of one embodiment of the present invention in a display portion. The display device of one embodiment of the present invention can easily have high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portion of various electronic devices.

[0321] Examples of electronic devices include electronic devices with relatively large screens, such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and audio playback devices.

[0322] In particular, the display device of one embodiment of the present invention can be suitably used in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices such as head-mounted displays, AR devices such as glasses-type devices, and MR devices.

[0323] The display device of one embodiment of the present invention preferably has an extremely high resolution such as HD (1280×720 pixels), FHD (1920×1080 pixels), WQHD (2560×1440 pixels), WQXGA (2560×1600 pixels), 4K (3840×2160 pixels), or 8K (7680×4320 pixels). In particular, a resolution of 4K, 8K, or more is preferable. The pixel density (definition) of the display device of one embodiment of the present invention is preferably 100 ppi or more, more preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using a display device having either or both of high resolution and high definition, it is possible to further improve the sense of realism and depth in electronic devices for personal use such as portable or home use. In addition, there is no particular limitation on the screen ratio (aspect ratio) of the display device of one embodiment of the present invention. For example, the display device can support various screen ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0324] The electronic device of this embodiment may have a sensor (including a function to sense, detect, or measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0325] The electronic device of the present embodiment can have various functions, such as a function of displaying various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, time, etc., a function of executing various software (programs), a wireless communication function, a function of reading out a program or data recorded on a recording medium, etc.

[0326] An example of a wearable device that can be worn on the head will be described with reference to Figures 16(A) to 16(D). These wearable devices have at least one of the following functions: a function to display AR content, a function to display VR content, a function to display SR content, and a function to display MR content. By having an electronic device have the function to display at least one of AR, VR, SR, and MR content, it is possible to enhance the user's sense of immersion.

[0327] Electronic device 700A shown in FIG. 16(A) and electronic device 700B shown in FIG. 16(B) each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0328] The display device of one embodiment of the present invention can be applied to the display panel 751. Thus, the electronic device can provide an extremely high-definition display.

[0329] Each of the electronic devices 700A and 700B can project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Since the optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visually recognized through the optical member 753. Therefore, each of the electronic devices 700A and 700B is an electronic device capable of AR display.

[0330] The electronic device 700A and the electronic device 700B may be provided with a camera capable of capturing an image of the front as an imaging unit. In addition, the electronic device 700A and the electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to the orientation in the display area 756.

[0331] The communication unit has a wireless communication device and can supply a video signal, etc., by the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential are supplied may be provided.

[0332] Furthermore, the electronic device 700A and the electronic device 700B are provided with a battery, which can be charged wirelessly and / or wired.

[0333] The housing 721 may be provided with a touch sensor module. The touch sensor module has a function of detecting that the outer surface of the housing 721 is touched. The touch sensor module detects a tap operation or a slide operation by the user, and can execute various processes. For example, a tap operation can execute a process such as pausing or resuming a video, and a slide operation can execute a process such as fast forwarding or rewinding. In addition, by providing a touch sensor module in each of the two housings 721, the range of operations can be expanded.

[0334] As the touch sensor module, various touch sensors can be applied. For example, various types of sensors can be adopted, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, an optical type, etc. In particular, it is preferable to apply a capacitance type or an optical type sensor to the touch sensor module.

[0335] When an optical touch sensor is used, a photoelectric conversion device (also called a photoelectric conversion element) can be used as the light receiving device. The active layer of the photoelectric conversion device can be made of either or both of an inorganic semiconductor and an organic semiconductor.

[0336] Electronic device 800A shown in FIG. 16(C) and electronic device 800B shown in FIG. 16(D) each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0337] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, an electronic device capable of displaying images with extremely high definition can be provided, which allows a user to feel a high sense of immersion.

[0338] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform three-dimensional display using parallax.

[0339] The electronic device 800A and the electronic device 800B can each be said to be electronic devices for VR. A user wearing the electronic device 800A or the electronic device 800B can view an image displayed on the display unit 820 through the lens 832.

[0340] It is preferable that electronic device 800A and electronic device 800B each have a mechanism capable of adjusting the left-right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes. It is also preferable that electronic device 800A and electronic device 800B each have a mechanism for adjusting the focus by changing the distance between lens 832 and display unit 820.

[0341] The mounting unit 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head. In Fig. 16(C) and other figures, the mounting unit 823 is shaped like the temples of glasses (also called joints or temples), but is not limited thereto. The mounting unit 823 may be shaped like a helmet or band, for example, as long as it can be worn by the user.

[0342] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. In addition, multiple cameras may be provided so as to be compatible with multiple angles of view, such as telephoto and wide angle.

[0343] Although an example having the imaging unit 825 is shown here, a distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object may be provided. That is, the imaging unit 825 is one aspect of the detection unit. As the detection unit, for example, an image sensor or a distance image sensor such as a LIDAR (Light Detection and Ranging) can be used. By using an image obtained by the camera and an image obtained by the distance image sensor, more information can be obtained, enabling more accurate gesture operation.

[0344] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having the vibration mechanism can be applied to one or more of the display unit 820, the housing 821, and the wearing unit 823. This makes it possible to enjoy video and audio by simply wearing the electronic device 800A without requiring a separate audio device such as headphones, earphones, or speakers.

[0345] The electronic device 800A and the electronic device 800B may each have an input terminal (also called an input unit). A cable for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device can be connected to the input terminal.

[0346] The electronic device of one embodiment of the present invention may have a function of wireless communication with the earphone 750. The earphone 750 has a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., audio data) from the electronic device through the wireless communication function. For example, the electronic device 700A shown in FIG. 16A has a function of transmitting information to the earphone 750 through the wireless communication function. Furthermore, for example, the electronic device 800A shown in FIG. 16C has a function of transmitting information to the earphone 750 through the wireless communication function.

[0347] The electronic device may also have an earphone unit. Electronic device 700B shown in Fig. 16(B) has earphone unit 727. For example, earphone unit 727 and a control unit may be configured to be connected to each other by wire. A part of the wiring connecting earphone unit 727 and the control unit may be disposed inside housing 721 or wearing unit 723.

[0348] Similarly, electronic device 800B shown in Fig. 16(D) has earphone unit 827. For example, earphone unit 827 and control unit 824 can be configured to be connected to each other by wire. A part of the wiring connecting earphone unit 827 and control unit 824 may be disposed inside housing 821 or wearing unit 823. In addition, earphone unit 827 and wearing unit 823 may have a magnet. This allows earphone unit 827 to be fixed to wearing unit 823 by magnetic force, which is preferable as it makes storage easier.

[0349] The electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may have one or both of an audio input terminal and an audio input mechanism. For example, a sound collector such as a microphone can be used as the audio input mechanism. The electronic device may have a function as a so-called headset by having the audio input mechanism.

[0350] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type devices (such as the electronic device 700A and the electronic device 700B) and goggles-type devices (such as the electronic device 800A and the electronic device 800B) are suitable.

[0351] Furthermore, the electronic device according to one embodiment of the present invention can transmit information to the earphones in a wired or wireless manner.

[0352] An electronic device 6500 shown in FIG. 17A is a portable information terminal that can be used as a smartphone.

[0353] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0354] The display device of one embodiment of the present invention can be applied to the display portion 6502.

[0355] FIG. 17B is a schematic cross-sectional view including the end portion of the housing 6501 on the microphone 6506 side.

[0356] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0357] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by an adhesive layer (not shown).

[0358] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and the folded back part is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0359] The display device of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while suppressing the thickness of the electronic device. In addition, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0360] 17C shows an example of a television set. In a television set 7100, a display portion 7000 is incorporated in a housing 7101. Here, the housing 7101 is supported by a stand 7103.

[0361] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0362] 17C can be operated using an operation switch provided on the housing 7101 and a separate remote control 7111. Alternatively, the display portion 7000 may be provided with a touch sensor, and the television set 7100 may be operated by touching the display portion 7000 with a finger or the like. The remote control 7111 may have a display portion that displays information output from the remote control 7111. Using an operation key or a touch panel provided on the remote control 7111, a channel and a volume can be operated, and an image displayed on the display portion 7000 can be operated.

[0363] The television device 7100 includes a receiver and a modem. The receiver can receive general television broadcasts. By connecting to a wired or wireless communication network via the modem, one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication can be performed.

[0364] 17D shows an example of a laptop personal computer. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, and the like. A display portion 7000 is incorporated in the housing 7211.

[0365] The display device of one embodiment of the present invention can be applied to the display portion 7000.

[0366] 17(E) and 17(F) show an example of digital signage.

[0367] 17E includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, an operation key (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0368] 17F shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0369] In FIG. 17E and FIG. 17F, the display device of one embodiment of the present invention can be applied to the display portion 7000.

[0370] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it catches people's attention, which can increase the advertising effect of, for example, advertisements.

[0371] Applying a touch panel to the display unit 7000 is preferable because it not only displays images or videos on the display unit 7000 but also allows the user to intuitively operate it. Furthermore, when used for providing information such as route information or traffic information, the intuitive operation can improve usability.

[0372] 17(E) and 17(F), the digital signage 7300 or the digital signage 7400 is preferably capable of wirelessly linking with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user. For example, advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or the information terminal 7411. By operating the information terminal 7311 or the information terminal 7411, the display on the display unit 7000 can be switched.

[0373] In addition, a game can be executed on the digital signage 7300 or the digital signage 7400 using the screen of the information terminal 7311 or the information terminal 7411 as an operation means (controller). This allows an unspecified number of users to participate in and enjoy the game at the same time.

[0374] The electronic devices shown in Figures 18(A) to 18(G) have a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to sense, detect, or measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone 9008, etc.

[0375] 18(A) to 18(G) have various functions. For example, the electronic devices may have a function of displaying various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, or time, a function of controlling processing by various software (programs), a wireless communication function, a function of reading and processing a program or data recorded on a recording medium, and the like. Note that the functions of the electronic devices are not limited to these, and the electronic devices may have various functions. The electronic devices may have multiple display units. In addition, the electronic devices may have a function of providing a camera or the like in the electronic device, taking still images or videos, and storing them in a recording medium (external or built-in to the camera), a function of displaying the taken images on the display unit, and the like.

[0376] The electronic devices shown in FIGS. 18A to 18G will be described in detail below.

[0377] FIG. 18A is a perspective view showing a mobile information terminal 9101. The mobile information terminal 9101 can be used as, for example, a smartphone. Note that the mobile information terminal 9101 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, and the like. The mobile information terminal 9101 can display text and image information on a plurality of surfaces. FIG. 18A shows an example in which three icons 9050 are displayed. Information 9051 shown in a dashed rectangle can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notification of incoming e-mail, SNS, phone call, etc., the title of e-mail or SNS, the sender's name, date and time, time, remaining battery level, radio wave intensity, and the like. Alternatively, the icon 9050 or the like may be displayed at the position where the information 9051 is displayed.

[0378] 18(B) is a perspective view showing a mobile information terminal 9102. The mobile information terminal 9102 has a function of displaying information on three or more surfaces of a display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9102 while the mobile information terminal 9102 is placed in a breast pocket of clothes. The user can check the display without taking the mobile information terminal 9102 out of the pocket and can determine, for example, whether to answer a call.

[0379] 18C is a perspective view showing a tablet terminal 9103. The tablet terminal 9103 is capable of executing various applications such as mobile phone, e-mail, text browsing and creation, music playback, Internet communication, computer games, etc. The tablet terminal 9103 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front side of a housing 9000, operation keys 9005 as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0380] FIG. 18D is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and charging with another information terminal through a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0381] 18(E) to 18(G) are perspective views showing a foldable mobile information terminal 9201. FIG. 18(E) shows the mobile information terminal 9201 in an unfolded state, FIG. 18(G) shows the mobile information terminal 9201 in a folded state, and FIG. 18(F) shows a perspective view of a state in the middle of changing from one of FIG. 18(E) and FIG. 18(G) to the other. The mobile information terminal 9201 has excellent portability in a folded state, and has excellent viewability of a display due to a seamless wide display area in an unfolded state. A display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm to 150 mm.

[0382] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments. [Explanation of symbols]

[0383] 10B Light-emitting devices 10C Light-emitting devices 10G Light Emitting Device 10M Light Emitting Device 10R Light Emitting Device 10X Light Emitting Device 10Y Light Emitting Device 11B Anode 11C Anode 11G anode 11M anode 11R Anode 11X Anode 11Y Anode 11 CO 12_a Transport layer 12_b Transport layer 12 Transport layer 13B Light-emitting layer 13B_a First light-emitting layer 13B_b Second light-emitting layer 13C_1 Emitting layer 13C_2 Emitting layer 13G Light-emitting layer 13G_a First light-emitting layer 13G_b Second light-emitting layer 13M_1 Emitting layer 13M_2 Emitting layer 13R Light-emitting layer 13R_a First light-emitting layer 13R_b Second light-emitting layer 13R_e Emitting layer 13R_h Light-emitting layer 13X_1 Emitting layer 13X_1e Emitting layer 13X_1h Light-emitting layer 13X_2 Emitting layer 13X_3 Emitting layer 13X_a First light-emitting layer 13X_b Second light-emitting layer 13X_c Third emitting layer 13Y_1 Emitting layer 13Y_2 Emitting layer 14_a Transport layer 14_b Transport layer 14 Transport layer 15 Cathode 19R Hole Blocking Layer 19X Hole Blocking Layer 19 Hole blocking layer 20G Electronic Block Layer 20R Electron Block Layer 20X Electronic Block Layer 20 Electron Block Layer 21 Middle Class 50B subpixel 50C Subpixel 50G subpixel 50M subpixels 50R subpixel 50X subpixel 50Y subpixel 100A display device 100B display device 100 display device 101 First electrode 102 Second electrode 103a EL layer 103b EL layer 103 EL layer 106a Charge generating layer 106b Charge generating layer 106 Charge generation layer 110 pixels 111a Hole injection layer 111b Hole injection layer 111 Hole injection layer 112a Hole transport layer 112b Hole transport layer 112 Hole transport layer 113a Light-emitting layer 113b Light-emitting layer 113c Emitting layer 113 Light-emitting layer 114b Electron transport layer 114 Electron transport layer 115b Electron injection layer 115 Electron injection layer 116 Electron Block Layer 117 Hole Blocking Layer 121 layers 122 Protective layer 123 Resin layer 124 Substrate 125 Insulating layer 140 Connection 240 capacity 241 Conductive Layer 243 Insulating Layer 245 Conductive Layer 254 Insulating layer 255a Insulating layer 255b Insulating layer 255c Insulation Layer 256 Plug 261 Insulating Layer 271 Plug 280 Display Module 281 Display section 282 Circuit section 283a Pixel circuit 283 Pixel circuit section 284a pixels 284 Pixel section 285 Terminal section 286 Wiring section 290 FPC 291 Substrate 292 Substrate 301 Substrate 310 Transistor 311 Conductive layer 312 Low resistance region 313 Insulating Layer 314 Insulating layer 315 Element Isolation Layer 700A electronic equipment 700B Electronic equipment 721 Case 723 Mounting Part 727 Earphones 750 Earphones 751 Display Panel 753 Optical Components 756 Display area 757 Frames 758 Nose pad 800A electronic equipment 800B Electronic equipment 820 Display section 821 Case 822 Communications Department 823 Mounting part 824 Control Unit 825 Imaging unit 827 Earphones 832 Lens 6500 Electronic equipment 6501 Case 6502 Display section 6503 Power button 6504 Button 6505 Speaker 6506 Microphone 6507 Camera 6508 Light source 6510 Protective materials 6511 Display Panel 6512 Optical components 6513 Touch Sensor Panel 6515 FPC 6516 IC 6517 Printed Circuit Board 6518 Battery 7000 Display 7100 Television equipment 7101 Case 7103 Stand 7111 Remote control device 7200 Notebook Personal Computer 7211 Case 7212 Keyboard 7213 Pointing Device 7214 External connection port 7300 Digital Signage 7301 Case 7303 Speaker 7311 Information terminal 7400 Digital Signage 7401 Pillar 7411 Information terminal 9000 Chassis 9001 Display section 9002 Camera 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Icon 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9101 Portable information terminal 9102 Portable information terminal 9103 Tablet PC 9200 Mobile Information Terminal 9201 Portable information terminals

Claims

1. The light emitting device includes first to third light emitting devices, the first light emitting device has a first anode, a first cathode, and a first light emitting layer between the first anode and the first cathode; the second light emitting device has a second anode, a second cathode, and a second light emitting layer between the second anode and the second cathode; the third light-emitting device has a third anode, a third cathode, and a third light-emitting layer and a fourth light-emitting layer between the third anode and the third cathode; the fourth light-emitting layer is located between the third light-emitting layer and the third cathode and is in contact with the third light-emitting layer; the emission of the first light emitting device, the emission of the second light emitting device, and the emission of the third light emitting device are different in color from one another; the first light-emitting layer and the third light-emitting layer have a first light-emitting material; the second light-emitting layer and the fourth light-emitting layer have a second light-emitting material; The first light-emitting substance and the second light-emitting substance have emission spectra with peak wavelengths different from each other.

2. In claim 1, a peak wavelength of an emission spectrum of the first luminescent material is longer than a peak wavelength of an emission spectrum of the second luminescent material; A display device, wherein the third light-emitting layer has a thickness smaller than a thickness of the fourth light-emitting layer.

3. In claim 1, a peak wavelength of an emission spectrum of the first luminescent material is longer than a peak wavelength of an emission spectrum of the second luminescent material; The display device, wherein the first light-emitting layer and the third light-emitting layer each include a hole-transporting material.

4. In claim 3, The first light emitting device comprises a hole blocking layer between the first light emitting layer and the first cathode.

5. In claim 1, a fourth light emitting device; the fourth light emitting device has a fourth anode, a fourth cathode, and a fifth light emitting layer between the fourth anode and the fourth cathode; the third light-emitting device has a sixth light-emitting layer between the third anode and the third cathode; the sixth light-emitting layer is located between the fourth light-emitting layer and the third cathode and is in contact with the fourth light-emitting layer; the fifth light-emitting layer and the sixth light-emitting layer each have a third light-emitting material; A display device, wherein the third light-emitting substance has an emission spectrum having a peak wavelength different from those of the first light-emitting substance and the second light-emitting substance.

6. The light emitting device includes first to third light emitting devices, the first light-emitting device has a first anode, a first cathode, a first light-emitting layer between the first anode and the first cathode, and a first hole-blocking layer; the first hole blocking layer is located between the first light emitting layer and the first cathode; the second light emitting device has a second anode, a second cathode, and a second light emitting layer between the second anode and the second cathode; the third light-emitting device has a third anode, a third cathode, and a third light-emitting layer and a fourth light-emitting layer between the third anode and the third cathode; the fourth light-emitting layer is located between the third light-emitting layer and the third cathode, the emission of the first light emitting device, the emission of the second light emitting device, and the emission of the third light emitting device are different in color from one another; the first light-emitting layer and the third light-emitting layer each have a first light-emitting substance and a hole-transporting material; the second light-emitting layer and the fourth light-emitting layer have a second light-emitting material; The first light-emitting substance and the second light-emitting substance have emission spectra with peak wavelengths different from each other.

7. In claim 6, the third light-emitting device comprises a second hole-blocking layer located between the third light-emitting layer and the fourth light-emitting layer.

8. The light emitting device includes first to third light emitting devices, the first light-emitting device has a first anode, a first cathode, and a first light-emitting layer, a second light-emitting layer, and a first intermediate layer between the first anode and the first cathode; the first intermediate layer is located between the first light-emitting layer and the second light-emitting layer; the second light-emitting device has a second anode, a second cathode, a third light-emitting layer between the second anode and the second cathode, a fourth light-emitting layer, and a second intermediate layer; the second intermediate layer is located between the third light-emitting layer and the fourth light-emitting layer; the third light-emitting device has a third anode, a third cathode, and a fifth light-emitting layer, a sixth light-emitting layer, and a third intermediate layer between the third anode and the third cathode; the third intermediate layer is located between the fifth light-emitting layer and the sixth light-emitting layer; the emission of the first light emitting device, the emission of the second light emitting device, and the emission of the third light emitting device are different in color from one another; the first light-emitting layer, the second light-emitting layer, and the fifth light-emitting layer each have a first light-emitting material; the third light-emitting layer, the fourth light-emitting layer, and the sixth light-emitting layer each have a second light-emitting material; The first light-emitting substance and the second light-emitting substance have emission spectra with peak wavelengths different from each other.

9. In claim 8, The display device, wherein the first intermediate layer, the second intermediate layer, and the third intermediate layer each contain an organic compound and an alkali metal or an alkaline earth metal.

10. In claim 8, A display device, wherein the first intermediate layer, the second intermediate layer, and the third intermediate layer each contain the same organic compound and the same alkali metal or alkaline earth metal.

11. In claim 8, a fourth light emitting device; the fourth light-emitting device has a fourth anode, a fourth cathode, and a seventh light-emitting layer, an eighth light-emitting layer, and a fourth intermediate layer between the fourth anode and the fourth cathode; the fourth intermediate layer is located between the seventh light-emitting layer and the eighth light-emitting layer; the third light-emitting device has a ninth light-emitting layer between the third anode and the third cathode; the ninth light-emitting layer is in contact with the sixth light-emitting layer, the seventh light-emitting layer, the eighth light-emitting layer, and the ninth light-emitting layer each have a third light-emitting material; A display device, wherein the third light-emitting substance has an emission spectrum having a peak wavelength different from those of the first light-emitting substance and the second light-emitting substance.

12. In claim 11, A display device, wherein the first intermediate layer, the second intermediate layer, the third intermediate layer, and the fourth intermediate layer each contain an organic compound and an alkali metal or an alkaline earth metal.

13. In claim 11, A display device, wherein the first intermediate layer, the second intermediate layer, the third intermediate layer, and the fourth intermediate layer each contain the same organic compound and the same alkali metal or alkaline earth metal.

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