Display device

Abstract

The invention relates to a display device. The display device comprises first to third light-emitting devices, the first light-emitting device comprises a first anode, a first cathode and a first light-emitting layer located between the first anode and the first cathode, and the second light-emitting device comprises a second anode, a second cathode and a second light-emitting layer located between the second anode and the second cathode. The third light-emitting device comprises a third anode, a third cathode, and a third light-emitting layer and a fourth light-emitting layer which are located 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, and the light-emitting colors of the first light-emitting device, the second light-emitting device and the third light-emitting device are different. The first and third light-emitting layers contain a first light-emitting substance, the second and fourth light-emitting layers contain a second light-emitting substance, and the first and second light-emitting substances have different emission spectrum peak wavelengths.

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-mentioned technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, a product or a composition of matter. Therefore, more specifically, as an example of the technical field of one embodiment of the present invention disclosed in this specification, a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a storage device, a camera device, a driving method of these devices or a manufacturing method of these devices can be cited. Background Art

[0002] The practical application of light-emitting devices (organic EL devices) using organic compounds and utilizing electroluminescence (EL) is very active. In the basic structure of these light-emitting devices, an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying voltage to the device, carriers are injected, and the recombination energy of the carriers is used to obtain light emission from the light-emitting material.

[0003] Because this light-emitting device is a self-luminous light-emitting device, it has advantages such as higher visibility and no need for backlight when used for pixels of a display compared to liquid crystals, so it is suitable for devices used in flat-panel displays. In addition, a display using this light-emitting device can be made thin and light, which is also a great advantage. Moreover, a very fast response speed is also one of its characteristics.

[0004] In a display using an organic EL device, in order to improve the color rendering capability, a fourth color sub-pixel such as yellow is sometimes required in addition to the three color sub-pixels of red, green, and blue. As an example of a method for realizing such a display, a method of forming a fourth color sub-pixel using a light-emitting device containing a light-emitting substance that emits yellow light can be cited. Patent document 1 discloses a light-emitting substance that emits yellow light and a light-emitting device using the substance.

[0005] In addition, as another example of a method for realizing such a display, the following method can be cited: a single-type light-emitting device that emits red, green, and blue light and a tandem-type light-emitting device that is manufactured using the same material as the single-type light-emitting device are manufactured on the same substrate, and a sub-pixel of a fourth color is formed using the tandem-type light-emitting device. Patent Document 2 discloses a structure of a display in which a single-type light-emitting device and a tandem-type light-emitting device are provided on the same substrate.

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-214726

[0007] [Patent Document 2] U.S. Patent Application Publication No. 2016 / 0155378 Summary of the invention

[0008] When a fourth color sub-pixel is required, the manufacturing method of manufacturing a light-emitting device using a light-emitting substance and a light-emitting layer of the fourth color may require additional steps, masks, and materials, which may increase the manufacturing cost.

[0009] In addition, in the method of manufacturing both the single-type light-emitting device and the tandem-type light-emitting device on the same substrate, the tandem-type light-emitting device requires an additional process and additional materials such as an intermediate layer (charge generation layer). Furthermore, in a display having such a structure, since different voltages need to be applied to the single-type light-emitting device and the tandem-type light-emitting device, an additional circuit structure is required, which may increase the manufacturing cost.

[0010] In view of this, an object of one embodiment of the present invention is to provide a display device that forms a sub-pixel of a fourth color without adding a process, a mask, a material, a circuit structure, etc. In addition, an object of one embodiment of the present invention is to provide a display device that reduces manufacturing costs. In addition, an object of one embodiment of the present invention is to provide an inexpensive display device. In addition, an object of one embodiment of the present invention is to provide a novel display device.

[0011] Note that the description of these purposes does not prevent the existence of other purposes. Note that one embodiment of the present invention does not necessarily achieve all of the above purposes. Note that purposes other than the above can be known and extracted from the description of the specification, drawings, claims, etc.

[0012] One embodiment of the present invention is a display device, which includes first to third light-emitting devices, the first light-emitting device includes a first anode, a first cathode and a first light-emitting layer located between the first anode and the first cathode, the second light-emitting device includes a second anode, a second cathode and a second light-emitting layer located between the second anode and the second cathode, the third light-emitting device includes a third anode, a third cathode and a third light-emitting layer and a fourth light-emitting layer located 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 light-emitting color of the first light-emitting device, the light-emitting color of the second light-emitting device and the light-emitting color of the third light-emitting device are different, the first light-emitting layer and the third light-emitting layer contain a first light-emitting substance, the second light-emitting layer and the fourth light-emitting layer contain a second light-emitting substance, and the peak wavelengths of the emission spectra of the first light-emitting substance and the second light-emitting substance are different.

[0013] In addition, one embodiment of the present invention is a display device, which includes first to third light-emitting devices, the first light-emitting device includes a first anode, a first cathode, and a first light-emitting layer located between the first anode and the first cathode, the second light-emitting device includes a second anode, a second cathode, and a second light-emitting layer located between the second anode and the second cathode, the third light-emitting device includes a third anode, a third cathode, and a third light-emitting layer and a fourth light-emitting layer located 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 in contact with the third light-emitting layer, the first light-emitting layer and the third light-emitting layer contain a first light-emitting substance, the second light-emitting layer and the fourth light-emitting layer contain a second light-emitting substance, the first light-emitting device does not contain the second light-emitting substance, the second light-emitting device does not contain the first light-emitting substance, and the peak wavelengths of the emission spectra of the first light-emitting substance and the second light-emitting substance are different.

[0014] In the display device having the above structures, it is more preferred 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 smaller than the thickness of the fourth light-emitting layer.

[0015] In addition, in the display device having each of the above structures, it is more preferred 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 first light-emitting layer and the third light-emitting layer contain a hole transport material. In addition, the hole transport property of the first light-emitting layer is preferably higher than the hole transport property of the second light-emitting layer. In addition, the hole transport property of the third light-emitting layer is preferably higher than the hole transport property of the fourth light-emitting layer. Furthermore, the first light-emitting device more preferably includes a hole blocking layer located between the first light-emitting layer and the first cathode.

[0016] In addition, one embodiment of the present invention is a display device having the above-mentioned structures, the display device also includes a fourth light-emitting device, the fourth light-emitting device includes a fourth anode, a fourth cathode and a fifth light-emitting layer located between the fourth anode and the fourth cathode, the third light-emitting device includes a sixth light-emitting layer located 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 contain a third light-emitting substance, and the peak wavelength of the emission spectrum of the third light-emitting substance is different from the peak wavelength of the emission spectrum of the first light-emitting substance and the second light-emitting substance.

[0017] In addition, another embodiment of the present invention is a display device, which includes first to third light-emitting devices, the first light-emitting device includes a first anode, a first cathode, a first light-emitting layer and a first hole blocking layer located between the first anode and the first cathode, the first hole blocking layer is located between the first light-emitting layer and the first cathode, the second light-emitting device includes a second anode, a second cathode and a second light-emitting layer located between the second anode and the second cathode, the third light-emitting device includes a third anode, a third cathode and a third light-emitting layer and a fourth light-emitting layer located 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 light-emitting color of the first light-emitting device, the light-emitting color of the second light-emitting device and the light-emitting color of the third light-emitting device are different, the first light-emitting layer and the third light-emitting layer contain a first light-emitting substance and a hole transport material, the second light-emitting layer and the fourth light-emitting layer contain a second light-emitting substance, and the peak wavelengths of the emission spectra of the first light-emitting substance and the second light-emitting substance are different.

[0018] In the display devices having the above structures, the third light-emitting device may also include a second hole blocking layer located between the third light-emitting layer and the fourth light-emitting layer. In addition, in the display devices having the above structures, the hole transport property of the first light-emitting layer is preferably higher than the hole transport property of the second light-emitting layer. The hole transport property of the third light-emitting layer is preferably higher than the hole transport property of the fourth light-emitting layer.

[0019] In addition, another embodiment of the present invention is a display device, which includes first to third light-emitting devices, the first light-emitting device includes a first anode, a first cathode, a first light-emitting layer located 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 includes a second anode, a second cathode, a third light-emitting layer located 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 includes a third anode, a third cathode and a fifth light-emitting layer located between the third anode and the third cathode, a sixth light-emitting layer and a third intermediate layer, the third intermediate layer is located between the fifth light-emitting layer and the sixth light-emitting layer, the light-emitting color of the first light-emitting device, the light-emitting color of the second light-emitting device and the light-emitting color of the third light-emitting device are different, the first light-emitting layer, the second light-emitting layer and the fifth light-emitting layer contain a first light-emitting substance, the third light-emitting layer, the fourth light-emitting layer and the sixth light-emitting layer contain a second light-emitting substance, and the peak wavelengths of the emission spectra of the first light-emitting substance and the second light-emitting substance are different.

[0020] In addition, one embodiment of the present invention is a display device, which includes first to third light-emitting devices, the first light-emitting device includes a first anode, a first cathode, a first light-emitting layer located 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 includes a second anode, a second cathode, a third light-emitting layer located 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 includes a third anode, a third cathode, and a fifth light-emitting layer, a sixth light-emitting layer and a third intermediate layer located 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 first light-emitting layer, the second light-emitting layer and the fifth light-emitting layer contain a first light-emitting substance, the third light-emitting layer, the fourth light-emitting layer and the sixth light-emitting layer contain a second light-emitting substance, the first light-emitting device does not contain the second light-emitting substance, the second light-emitting device does not contain the first light-emitting substance, and the peak wavelengths of the emission spectra of the first light-emitting substance and the second light-emitting substance are different.

[0021] In the display device having the above structure, the first intermediate layer, the second intermediate layer, and the third intermediate layer more preferably all contain an organic compound and an alkali metal or an alkaline earth metal.

[0022] Furthermore, in the display device having the above structure, the first intermediate layer, the second intermediate layer, and the third intermediate layer more preferably contain the same organic compound and the same alkali metal or alkaline earth metal.

[0023] In addition, one embodiment of the present invention is a display device having the above structure, which also includes a fourth light-emitting device, the fourth light-emitting device includes a fourth anode, a fourth cathode and a seventh light-emitting layer located between the fourth anode and the fourth cathode, an eighth light-emitting layer and a fourth intermediate layer, the fourth intermediate layer is located between the seventh light-emitting layer and the eighth light-emitting layer, the third light-emitting device includes a ninth light-emitting layer located 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 contain a third light-emitting substance, and the peak wavelength of the emission spectrum of the third light-emitting substance is different from the peak wavelength of the emission spectrum of the first light-emitting substance and the second light-emitting substance.

[0024] In the display device having the above structure, the first intermediate layer, the second intermediate layer, the third intermediate layer, and the fourth intermediate layer more preferably all contain an organic compound and an alkali metal or an alkaline earth metal.

[0025] Furthermore, in the display device having the above structure, the first intermediate layer, the second intermediate layer, the third intermediate layer, and the fourth intermediate layer more preferably contain the same organic compound and the same alkali metal or alkaline earth metal.

[0026] According to one embodiment of the present invention, a display device can be provided that forms a sub-pixel of a fourth color without adding a process, a mask, a material, a circuit structure, etc. In addition, according to one embodiment of the present invention, a display device that reduces manufacturing costs can be provided. In addition, according to one embodiment of the present invention, a low-cost display device can be provided. In addition, according to one embodiment of the present invention, a novel display device can be provided.

[0027] Note that the description of these effects does not prevent the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of the above effects. Note that effects other than the above can be known and extracted from the description of the specification, drawings, claims, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1A is a plan view illustrating the structure of a display device according to an embodiment, Figure 1B is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0029] Figure 2A and Figure 2B is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0030] Figure 3A and Figure 3B is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0031] Figure 4A and Figure 4B is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0032] Figure 5A and Figure 5B is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0033] Figure 6 is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0034] Figure 7 is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0035] FIG. 8A to FIG. 8C is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0036] Fig. 9A is a plan view illustrating the structure of a display device according to an embodiment, Fig. 9B is a cross-sectional view illustrating a structure of a display device according to an embodiment;

[0037] FIG. 10A to FIG. 10D is a cross-sectional view showing an example of a method for manufacturing a display device;

[0038] FIG. 11A to FIG. 11D is a cross-sectional view showing an example of a method for manufacturing a display device;

[0039] Fig. 12A and Fig. 12B is a cross-sectional view showing an example of a method for manufacturing a display device;

[0040] FIG. 13A to FIG. 13F is a diagram illustrating a light emitting device;

[0041] Fig.14A and Fig. 14B is a perspective view showing an example of a display device;

[0042] Fig.15 is a cross-sectional view showing an example of a display device;

[0043] FIG. 16A to FIG. 16D is a diagram showing an example of an electronic device;

[0044] FIG. 17A to FIG. 17F is a diagram showing an example of an electronic device;

[0045] FIG. 18A to FIG. 18G is a diagram showing an example of an electronic device. DETAILED DESCRIPTION

[0046] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the contents described below, and its mode and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents recorded in the embodiments shown below.

[0047] In addition, for ease of understanding, the position, size, range, etc. of each structure shown in the drawings and the like may not represent its actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings and the like.

[0048] In addition, in this specification, for the sake of convenience, ordinal numbers such as first and second are added, but they do not sometimes indicate the order of processes or the order of stacking. Therefore, for example, "first" can be appropriately replaced with "second" or "third" for description. In addition, the ordinal numbers recorded in this specification and the like are sometimes inconsistent with the ordinal numbers used to specify one embodiment of the present invention.

[0049] In this specification and the like, when components of the invention are described using drawings, the same reference numerals may be used in common in different drawings to indicate the same parts.

[0050] In addition, in this specification, "film" and "layer" may be interchanged. For example, "conductive layer" may be interchanged with "conductive film". Or, "insulating film" may be interchanged with "insulating layer".

[0051] Implementation Method 1

[0052] In this embodiment, refer to Figures 1A to 9B A display device according to one embodiment of the present invention will be described.

[0053] Figure 1A A top view of a display device 100 as a display device according to one embodiment of the present invention is shown. The display device 100 includes a display unit in which a plurality of pixels 110 are arranged, and a connection unit 140 outside the display unit. In the display unit, a plurality of sub-pixels are arranged in a matrix. Figure 1A Two rows and eight columns of sub-pixels are shown, and these sub-pixels constitute two rows and two columns of pixels 110. In addition, the connection portion 140 may also be referred to as a cathode contact portion.

[0054] Figure 1A The top surface shape of the sub-pixel shown is equivalent to the top surface shape of the light-emitting region. In this specification, the top surface shape refers to the shape when viewed from a plane, that is, the shape when viewed from above. In addition, as examples of the top surface shape of the sub-pixel, a triangle, a quadrangle (including a rectangle, a rhombus, a square), a pentagon or other polygon, the above polygonal shapes with rounded corners, an ellipse or a circle, etc. can be cited.

[0055] In addition, the circuit layout constituting the sub-pixel is not limited to Figure 1A Within the scope of the sub-pixel shown, the components of the circuit can also be arranged outside it. Figure 1A A portion or all of the transistors included in the sub-pixel 50R shown may also be located outside the sub-pixel 50R. Figure 1A The sub-pixel 50R, the sub-pixel 50G, the sub-pixel 50B, or the sub-pixel 50X shown may be arranged so as to straddle a plurality of the above ranges.

[0056] exist Figure 1A In the embodiment, the aperture ratios (also referred to as the size or the size of the light-emitting area) of the sub-pixels 50R, 50G, 50B, and 50X are the same or substantially the same, 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 appropriately determined. The aperture ratios of the sub-pixels 50R, 50G, 50B, and 50X can be different from each other, or two or more of them can be the same or substantially the same.

[0057] Figure 1A The pixels 110 are shown arranged in a stripe pattern. Figure 1A The pixel 110 shown is composed of four sub-pixels, namely, a sub-pixel 50R, a sub-pixel 50G, a sub-pixel 50B, and a sub-pixel 50X. The sub-pixels 50R, 50G, 50B, and 50X respectively present light of different colors. As the sub-pixels 50R, 50G, and 50B, sub-pixels of red (R), green (G), and blue (B) can be cited. In addition, as the sub-pixel 50X, sub-pixels of yellow (Y), cyan (C), magenta (M), and white (W) can be cited.

[0058] In this specification and the like, the row direction, the column direction, and the depth direction may be referred to as the X direction, the Y direction, and the Z direction, respectively. Figure 1A An example is shown in which sub-pixels of different colors are arranged in the X direction and sub-pixels of the same color are arranged in the Y direction.

[0059] Figure 1B Shown along Figure 1A The cross-sectional view of the dot-dash line X1-X2 in FIG. FIG. 2A to FIG. 9B Shown along Figure 1A A deformation example of the cross-sectional view taken along the dashed line X1-X2 in FIG.

[0060] In the display device 100, the light-emitting devices 10R, 10G, 10B, and 10X are provided on a layer 121 including transistors (not shown), and a protective layer 122 is provided to cover these light-emitting devices. Furthermore, a substrate 124 is bonded thereto via a resin layer 123. In addition, an insulating layer 125 is provided in a region between adjacent light-emitting devices.

[0061] The display device according to one embodiment of the present invention is preferably a top emission type display device that emits light in a direction opposite to a substrate on which a light-emitting device is formed.

[0062] As layer 121, for example, a stacked structure may be used, in which a plurality of transistors (not shown) are provided on a substrate and an insulating layer is provided in a manner covering the transistors. Layer 121 may also include a recess between adjacent light-emitting devices. For example, a recess may also be provided in the insulating layer located on the outermost surface of layer 121. An example of the structure of layer 121 will be described in Embodiment 4.

[0063] The light emitting device 10R emits a different light color from the light emitting device 10G, from the light emitting device 10B, and from the light emitting device 10X. For example, it is preferred 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. In addition, the light emitting device 10X preferably emits yellow (Y), cyan (C), magenta (M), or white (W) light.

[0064] like Figure 1B As shown, in the display device 100, the anode 11R, the anode 11G, the anode 11B and the anode 11X are provided on the layer 121, the hole injection / transport layer 12 is provided on the anode 11R, the anode 11G, the anode 11B and the anode 11X, the light-emitting layer 13R, the light-emitting layer 13G, the light-emitting layer 13B and the light-emitting layer 13X_1 are provided on the hole injection / transport layer 12, the light-emitting layer 13X_2 is provided on the light-emitting layer 13X_1, the electron injection / transport layer 14 is provided on the light-emitting layer 13R, the light-emitting layer 13G, the light-emitting layer 13B and the light-emitting layer 13X_2, and the cathode 15 is formed on the electron injection / transport layer 14, and the light-emitting devices 10R, 10G, 10B, 10X are provided. In addition, the hole injection / transport layer 12 preferably has a stacked structure, for example, preferably has a stacked structure in which a hole injection layer and a hole transport layer are stacked in sequence from one side of each anode. The electron injection / transport layer 14 preferably has a stacked structure, for example, preferably has a stacked structure in which an electron transport layer and an electron injection layer are stacked in this order from one side of each light-emitting layer.

[0065] The hole injection / transport layer 12, the electron injection / transport layer 14 and the cathode 15 are preferably layers commonly used between the light-emitting devices (hereinafter sometimes referred to as common layers). In addition, the light-emitting layers 13R, 13G, 13B, 13X_1, and 13X_2 are preferably layers formed in each light-emitting device by vacuum evaporation using a metal mask.

[0066] The light emitting device 10R includes a hole injection / transport layer 12, a light emitting layer 13R, and an electron injection / transport layer 14 located 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. In addition, the light emitting layer 13R contains at least a light emitting substance R. As the light emitting substance R, a light emitting substance that emits red light can be used.

[0067] The light-emitting device 10G includes a hole injection / transport layer 12, a light-emitting layer 13G, and an electron injection / transport layer 14 located 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. In addition, the light-emitting layer 13G contains at least a light-emitting substance G. As the light-emitting substance G, a light-emitting substance that emits green light can be used.

[0068] The light emitting device 10B includes a hole injection / transport layer 12, a light emitting layer 13B, and an electron injection / transport layer 14 located 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. In addition, the light emitting layer 13B contains at least a light emitting substance B. As the light emitting substance B, a substance that emits blue light can be used.

[0069] In this specification, etc., the blue wavelength region refers to a wavelength region of 400 nm or more and less than 490 nm, and blue luminescence is luminescence having at least one emission spectrum peak in this region. In addition, the green wavelength region refers to a wavelength region of 490 nm or more and less than 580 nm, and green luminescence is luminescence having at least one emission spectrum peak in this region. In addition, the red wavelength region refers to a wavelength region of 580 nm or more and less than 750 nm, and red luminescence is luminescence having at least one emission spectrum peak in this region.

[0070] The light-emitting device 10X includes a hole injection / transport layer 12 located between an anode 11X and a cathode 15, a light-emitting layer stacked in such a manner that a plurality of light-emitting layers having different light-emitting colors are in contact (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 the light-emitting device 10X is preferably 2 or 3. By stacking light-emitting layers having different light-emitting colors, the light-emitting device 10X can emit light of a color different from that of each light-emitting layer.

[0071] Figure 1B An example is shown in which the light-emitting device 10X includes a stacked light-emitting layer 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.

[0072] Figure 3A An example of a light-emitting device 10X including a stacked light-emitting layer composed of three light-emitting layers (13X_1, 13X_2, 13X_3) is shown. 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. In addition, 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.

[0073] Each light-emitting layer included in the light-emitting device 10X is a layer formed by vacuum evaporation using a metal mask in the same process as any of the light-emitting layers 13R, 13G, and 13B. By adopting this structure, the light-emitting device 10X can be manufactured without adding a process and materials for providing the light-emitting device 10X in the display device 100, so that the cost of the display device 100 can be reduced.

[0074] In this specification, when it is recorded that a certain light-emitting layer is a layer formed by a vacuum evaporation method using a metal mask in the same process as the light-emitting layer A, it means that the light-emitting layer is a layer containing the same light-emitting substance as the light-emitting layer A. In addition, it means that the light-emitting layer and the light-emitting layer A contain the same material and are composed of the same material. In addition, it means that the thickness of the light-emitting layer is equal to the thickness of the light-emitting layer A. In this specification, when it is recorded as "same", it may also be different within the range of allowable thickness accuracy and composition variation of the deposition device. In addition, in this specification, "in the same process" can also be said to be "at the same time".

[0075] Hereinafter, for the sake of convenience, a layer formed by vacuum evaporation using a metal mask in the same process as the light-emitting layer 13R is sometimes referred to as a layer containing the light-emitting substance R. In addition, a layer formed by vacuum evaporation using a metal mask in the same process as the light-emitting layer 13G is sometimes referred to as a layer containing the light-emitting substance G. In addition, a layer formed by vacuum evaporation using a metal mask in the same process as the light-emitting layer 13B is sometimes referred to as a layer containing the light-emitting substance B.

[0076] like Figure 1B As shown, when the light-emitting device 10X includes a stacked light-emitting layer composed of two light-emitting layers (13X_1, 13X_2), and one of the two light-emitting layers is a layer containing a light-emitting substance R and the other is a layer containing a light-emitting substance G, the light-emitting device 10X can emit yellow (Y) light. Hereinafter, the light-emitting device 10X including this combination of light-emitting layers is sometimes referred to as a yellow (Y) light-emitting device 10X.

[0077] In addition, if Figure 1B As shown, when the light-emitting device 10X includes a stacked light-emitting layer composed of two light-emitting layers (13X_1, 13X_2), and one of the two light-emitting layers is a layer containing a light-emitting substance R and the other is a layer containing a light-emitting substance B, the light-emitting device 10X can emit magenta (M) light. Hereinafter, the light-emitting device 10X including this combination of light-emitting layers is sometimes referred to as a magenta (M) light-emitting device 10X.

[0078] In addition, if Figure 1BAs shown, when the light-emitting device 10X includes a stacked light-emitting layer composed of two light-emitting layers (13X_1, 13X_2), and one of the two light-emitting layers is a layer containing a light-emitting substance G and the other is a layer containing a light-emitting substance B, the light-emitting device 10X can emit cyan (C) light. Hereinafter, the light-emitting device 10X having this combination of light-emitting layers is sometimes referred to as a cyan (C) light-emitting device 10X.

[0079] In addition, if Figure 3A As shown, when the light emitting device 10X includes a stacked light emitting layer composed of three light emitting layers (13X_1, 13X_2, 13X_3), and the three light emitting layers are respectively a layer containing a light emitting substance R, a layer containing a light emitting substance G, and a layer containing a light emitting substance B, the light emitting device 10X can emit white (W) light. Hereinafter, the light emitting device 10X including this combination of light emitting layers is sometimes referred to as a white (W) light emitting device 10X.

[0080] Note that in a light-emitting device in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different light-emitting colors are directly stacked, the light-emitting layer L that emits light with a long wavelength may have a higher light-emitting intensity than the light-emitting layer S that emits light with a short wavelength. (In this case, the peak wavelength of the emission spectrum of the light-emitting substance x contained in the light-emitting layer L is located on the long wavelength side compared to the light-emitting substance y contained in the light-emitting layer S.) This is because the light-emitting substance x has lower excitation energy than the light-emitting substance y and is easily excited, so that in the case where the recombination center of the light-emitting device is located near the interface between the light-emitting layer L and the light-emitting layer S, the recombination energy is easily transferred to the light-emitting substance x.

[0081] Therefore, as one embodiment of the present invention, the following structure can be cited: in a light-emitting device including two light-emitting layers (light-emitting layer L and light-emitting layer S) directly stacked with different luminescent colors, the recombination center of carriers (holes and electrons) is shifted from the interface between the light-emitting layer L and the light-emitting layer S to the light-emitting layer S.

[0082] Preferably, when the light-emitting device 10X includes a stacked light-emitting layer composed of two light-emitting layers (13X_1, 13X_2) and the light-emitting layer 13X_1 and the light-emitting layer 13X_2 of the two light-emitting layers (13X_1, 13X_2) are, for example, a light-emitting layer L exhibiting long-wavelength light emission and a light-emitting layer S exhibiting short-wavelength light emission, respectively, the recombination center is shifted toward the light-emitting layer S by setting the thickness of the light-emitting layer L to which recombination energy is easily transferred to be smaller than the thickness of the light-emitting layer S.

[0083] Specifically, in the yellow (Y) light-emitting device 10X, it is preferable to adopt a structure in which the thickness of the layer containing the light-emitting substance R in the light-emitting layer 13X_1 and the light-emitting layer 13X_2 is smaller than the thickness of the layer containing the light-emitting substance G. For example, in the case where the light-emitting layer 13X_1 is a layer containing the light-emitting substance R and the light-emitting layer 13X_2 is a layer containing the light-emitting substance G, it is preferable to adopt a structure in which the light-emitting layer 13X_1 is thinner than the light-emitting layer 13X_2. In addition, in the magenta (M) light-emitting device 10X, it is preferable to adopt a structure in which the thickness of the layer containing the light-emitting substance R in the light-emitting layer 13X_1 and the light-emitting layer 13X_2 is smaller than the thickness of the layer containing the light-emitting substance B. For example, in the case where the light-emitting layer 13X_1 is a layer containing the light-emitting substance R and the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, In the case of Preferred The light-emitting layer 13X_1 is thinner than the light-emitting layer 13X_2. In addition, in the cyan (C) light-emitting device 10X, it is preferable to adopt a structure in which the thickness of the layer containing the light-emitting substance G in the light-emitting layer 13X_1 and the light-emitting layer 13X_2 is less than the thickness of the layer containing the light-emitting substance B. For example, in the case where the light-emitting layer 13X_1 is a layer containing the light-emitting substance G and the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, it is preferable to adopt a structure in which the light-emitting layer 13X_1 is thinner than the light-emitting layer 13X_2. By adopting this structure, the recombination center can be shifted to the light-emitting layer S, thereby improving the light-emitting intensity of the light-emitting layer S. 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 light-emitting efficiency of the light-emitting device 10X.

[0084] Figure 2A and Figure 2B A specific structural example in which the thicknesses of the light emitting layer 13X_1 and the light emitting layer 13X_2 are set differently is shown. Here, as an example, a case where the light emitting device 10X is a yellow (Y) light emitting device is described.

[0085] exist Figure 2A In the embodiment, the light-emitting layer 13X_1 is a light-emitting layer that emits light of a short wavelength and is a layer containing a light-emitting substance G. In addition, the light-emitting layer 13X_2 is a light-emitting layer that emits light of a long wavelength and is a layer containing a light-emitting substance R. Figure 2A As shown, in this case, the thickness of the light-emitting layer 13X_2 is preferably smaller than the thickness of the light-emitting layer 13X_1. Here, as described above, the layer containing the light-emitting substance G refers to a layer formed by vacuum evaporation using a metal mask in the same process as the light-emitting layer 13G, and the layer containing the light-emitting substance R refers to a layer formed by vacuum evaporation 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.

[0086] exist Figure 2BIn the embodiment, the light-emitting layer 13X_1 is a light-emitting layer that emits light of a long wavelength and is a layer containing a light-emitting substance R. In addition, the light-emitting layer 13X_2 is a light-emitting layer that emits light of a short wavelength and is a layer containing a light-emitting substance G. Figure 2B As shown, in this case, the thickness of the light emitting layer 13X_1 is preferably smaller than the thickness of the light emitting layer 13X_2. In addition, in this case, it can be said that the light emitting layer 13R is thinner than the light emitting layer 13G.

[0087] Furthermore, when the light-emitting device 10X includes a stacked light-emitting layer composed of three light-emitting layers (13X_1, 13X_2, 13X_3), it is preferred that the thickness of the layer containing the light-emitting substance R, the layer containing the light-emitting substance G, and the layer containing the light-emitting substance B in the three color light-emitting layers (13X_1, 13X_2, 13X_3) be increased in the order of. By adopting this structure, the recombination center can be shifted from each stacked layer interface to the light-emitting layer that emits light with a short wavelength, thereby improving the light emission intensity of the light-emitting layer that emits light with a short wavelength, and good light emission can be obtained from the light-emitting layer 13X_1, the light-emitting layer 13X_2, and the light-emitting layer 13X_3.

[0088] Figure 3B The specific structure is shown in FIG. Figure 3B In the embodiment, the light-emitting layer 13X_1 is a layer containing a light-emitting substance R. In addition, the light-emitting layer 13X_2 is a layer containing a light-emitting substance G. In addition, the light-emitting layer 13X_3 is a layer containing a light-emitting substance B. Figure 3B As shown, in this case, the thickness of the light-emitting layer 13X_2 is preferably greater than the thickness of the light-emitting layer 13X_1, and the thickness of the light-emitting layer 13X_3 is preferably greater than the thickness of the light-emitting layer 13X_2. Here, as described above, the layer containing the light-emitting substance G refers to a layer formed by vacuum evaporation using a metal mask in the same process as the light-emitting layer 13G, the layer containing the light-emitting substance R refers to a layer formed by vacuum evaporation using a metal mask in the same process as the light-emitting layer 13R, and the layer containing the light-emitting substance B refers to a layer formed by vacuum evaporation 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.

[0089] That is to say, in the case where the light-emitting device 10X includes a stacked light-emitting layer in which a plurality of light-emitting layers having different light-emitting colors are directly stacked, the recombination center of the stacked interface can be shifted toward the light-emitting layer that emits light of a short wavelength by thinning the thickness of the light-emitting layer that emits light of a long wavelength among the light-emitting layers that constitute the stacked interface, thereby improving the light-emitting efficiency of the light-emitting device 10X.

[0090] In addition, as one embodiment of the present invention, the following structure can be cited: in a light-emitting device including a stacked light-emitting layer including two light-emitting layers (light-emitting layer L and light-emitting layer S) with different light-emitting colors directly stacked between a reflective electrode and a transmissive electrode, the light-emitting layer S and the light-emitting layer L are stacked in sequence along the direction of light emission (in other words, the light-emitting layer S and the light-emitting layer L are stacked in sequence from the side close to the reflective electrode). By adopting this structure, the distance between the light-emitting layer S and the reflective electrode becomes shorter, and the distance between the light-emitting layer L and the reflective electrode becomes longer, thereby facilitating optical adjustment. In particular, by adopting this structure in a light-emitting device having a microcavity structure, optical adjustment is facilitated, so it is preferred. The details of the microcavity structure will be described in Embodiment 3.

[0091] Therefore, in Figure 1B In the light-emitting device 10X shown, the following combination is preferably adopted: the anode 11X is a reflective electrode, the cathode 15 is a transmissive electrode, 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 preferred that the light-emitting layer 13X_1 is a layer containing a light-emitting substance G, and the light-emitting layer 13X_2 is a layer containing a light-emitting substance R. Alternatively, in the magenta (M) light-emitting device 10X, it is preferred that the light-emitting layer 13X_1 is a layer containing a light-emitting substance B, and the light-emitting layer 13X_2 is a layer containing a light-emitting substance R. Alternatively, in the cyan (C) light-emitting device 10X, it is preferred that the light-emitting layer 13X_1 is a layer containing a light-emitting substance B, and the light-emitting layer 13X_2 is a layer containing a light-emitting substance G.

[0092] In another embodiment of the present invention, by changing the stacking order of the light-emitting layer L and the light-emitting layer S, the light emission intensity of each light-emitting layer changes, thereby adjusting the chromaticity.

[0093] For example, in Figure 1B In the light-emitting device 10X shown, the following combination may be adopted: the light-emitting layer 13X_1 of the two light-emitting layers is the light-emitting layer L, and the light-emitting layer 13X_2 is the light-emitting layer S. Specifically, in the yellow (Y) light-emitting device 10X, the light-emitting layer 13X_1 may be a layer containing a light-emitting substance R, and the light-emitting layer 13X_2 may be a layer containing a light-emitting substance G. Alternatively, in the magenta (M) light-emitting device 10X, the light-emitting layer 13X_1 may be a layer containing a light-emitting substance R, and the light-emitting layer 13X_2 may be a layer containing a light-emitting substance B. Alternatively, in the cyan (C) light-emitting device 10X, the light-emitting layer 13X_1 may be a layer containing a light-emitting substance G, and the light-emitting layer 13X_2 may be a layer containing a light-emitting substance B.

[0094] In addition, Figure 3AIn the white (W) light-emitting device 10X shown, among the three color light-emitting layers, the light-emitting layer 13X_1 may be a layer containing the light-emitting substance R, the light-emitting layer 13X_2 may be a layer containing the light-emitting substance G, and the light-emitting layer 13X_3 may be a layer containing the light-emitting substance B.

[0095] Furthermore, as another embodiment of the present invention, the following structure can be cited: in a light-emitting device including a stacked light-emitting layer in which two light-emitting layers (light-emitting layer L and light-emitting layer S) with different luminescent colors are directly stacked, the recombination center is shifted from the interface between the light-emitting layer L and the light-emitting layer S to the light-emitting layer S by improving the carrier transport property of the light-emitting layer L. Furthermore, in the case where the light-emitting device 10X includes a stacked light-emitting layer in which a plurality of light-emitting layers with different luminescent colors are directly stacked, by improving the carrier transport property of the light-emitting layer that emits light with 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 with a short wavelength, so that the luminous efficiency of the light-emitting device 10X can be improved.

[0096] In addition, in the case of improving the carrier transportability of the light-emitting layer located on the anode side of the above-mentioned stacked light-emitting layer, it is preferred to improve the hole transportability of the light-emitting layer. That is, the light-emitting layer preferably contains a hole transport material, and its hole transportability is more preferably higher than that of the light-emitting layer located on the cathode side. In addition, in the case of improving the carrier transportability of the light-emitting layer located on the cathode side of the multiple light-emitting layers, it is preferred to improve the electron transportability of the light-emitting layer. That is, the light-emitting layer preferably contains an electron transport material, and its electron transportability is more preferably higher than that of the light-emitting layer located on the anode side. Structural examples of hole transport materials and electron transport materials will be described in Embodiment 3.

[0097] Therefore, in the light-emitting device 10X including two light-emitting layers, it is preferred to improve the carrier transport property of the light-emitting layer that emits light with a long wavelength among the light-emitting layers 13X_1 and 13X_2. For example, in the case where the light-emitting layer 13X_1 emits light with a longer wavelength than the light-emitting layer 13X_2, it is preferred to improve the hole transport property of the light-emitting layer 13X_1. Specifically, the light-emitting layer 13X_1 preferably contains a hole transport material or has a higher hole transport property than the light-emitting layer 13X_2. Alternatively, in the case where the light-emitting layer 13X_2 emits light with a longer wavelength than the light-emitting layer 13X_1, it is preferred to improve the electron transport property of the light-emitting layer 13X_2. Specifically, the light-emitting layer 13X_2 preferably contains an electron transport material or has a higher electron transport property than the light-emitting layer 13X_1. By adopting this structure, the recombination center can be shifted from the stacking interface of the light-emitting layer 13X_1 and the light-emitting layer 13X_2 to the light-emitting layer that emits short wavelength light, thereby improving the luminous intensity of the light-emitting layer that emits short wavelength light, and obtaining good luminescence from both the light-emitting layer that emits long wavelength light and the light-emitting layer that emits short wavelength light.

[0098] Specifically, in the yellow (Y) light-emitting device 10X, it is preferable to improve the carrier transport property of the layer containing the light-emitting substance R in the light-emitting layer 13X_1 and the light-emitting layer 13X_2. For example, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance R and the light-emitting layer 13X_2 is a layer containing the light-emitting substance G, it is preferable that the light-emitting layer 13X_1 contains a hole transport material or has a higher hole transport property than the light-emitting layer 13X_2. In addition, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance G and the light-emitting layer 13X_2 is a layer containing the light-emitting substance R, it is preferable that the light-emitting layer 13X_2 contains an electron transport material or has a higher electron transport property than the light-emitting layer 13X_1.

[0099] In the magenta (M) light-emitting device 10X, it is preferable to improve the carrier transport property of the layer containing the light-emitting substance R in the light-emitting layer 13X_1 and the light-emitting layer 13X_2. For example, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance R and the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, it is preferable that the light-emitting layer 13X_1 contains a hole transport material or has a higher hole transport property than the light-emitting layer 13X_2. In addition, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance B and the light-emitting layer 13X_2 is a layer containing the light-emitting substance R, it is preferable that the light-emitting layer 13X_2 contains an electron transport material or has a higher electron transport property than the light-emitting layer 13X_1.

[0100] In the cyan (C) light-emitting device 10X, it is preferable to improve the carrier transport property of the layer containing the light-emitting substance G in the light-emitting layer 13X_1 and the light-emitting layer 13X_2. For example, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance G and the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, it is preferable that the light-emitting layer 13X_1 contains a hole transport material or has a higher hole transport property than the light-emitting layer 13X_2. In addition, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance B and the light-emitting layer 13X_2 is a layer containing the light-emitting substance G, it is preferable that the light-emitting layer 13X_2 contains an electron transport material or has a higher electron transport property than the light-emitting layer 13X_1.

[0101] As described above, the layer containing the light-emitting substance R refers to a layer formed by a vacuum evaporation method using a metal mask in the same process as the light-emitting layer 13R. That is, improving the carrier transportability of the layer containing the light-emitting substance R in the light-emitting layer 13X_1 and the light-emitting layer 13X_2 means also improving the carrier transportability of the light-emitting layer 13R. In addition, in the case where the light-emitting layer 13X_1 is a layer containing the light-emitting substance R and contains a hole transport material, it can be said that the light-emitting layer 13R also contains a hole transport material. In addition, in the case where the light-emitting layer 13X_2 is a layer containing the light-emitting substance R and contains an electron transport material, it can be said that the light-emitting layer 13R also contains an electron transport material.

[0102] In addition, as described above, the layer containing the light-emitting substance G refers to a layer formed by a vacuum evaporation 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 containing the light-emitting substance R, the light-emitting layer 13X_2 is a layer containing the light-emitting substance G, and the hole transport property of the light-emitting layer 13X_1 is higher than that of the light-emitting layer 13X_2, it can be said that the hole transport property of the light-emitting layer 13R is higher than that of the light-emitting layer 13G. In addition, 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 G, and the electron transport property of the light-emitting layer 13X_2 is higher than that of the light-emitting layer 13X_1, it can be said that the electron transport property of the light-emitting layer 13R is higher than that of the light-emitting layer 13G.

[0103] In addition, as described above, the layer containing the light-emitting substance B refers to a layer formed by a vacuum evaporation 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 hole transport property of the light-emitting layer 13X_1 is higher than that of the light-emitting layer 13X_2, it can be said that the hole transport property of the light-emitting layer 13R is higher than that of the light-emitting layer 13B. In addition, 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 electron transport property of the light-emitting layer 13X_2 is higher than that of the light-emitting layer 13X_1, it can be said that the electron transport property of the light-emitting layer 13R is higher than that of the light-emitting layer 13B.

[0104] Similarly, improving the carrier transport properties of the layer containing the light-emitting substance G in the light-emitting layer 13X_1 and the light-emitting layer 13X_2 means also improving the carrier transport properties of the light-emitting layer 13G. In addition, when the light-emitting layer 13X_1 is a layer containing the light-emitting substance G and contains a hole transport material, it can be said that the light-emitting layer 13G also contains a hole transport material. In addition, when the light-emitting layer 13X_2 is a layer containing the light-emitting substance G and contains an electron transport material, it can be said that the light-emitting layer 13G also contains an electron transport material.

[0105] In addition, 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 hole transport property of the light-emitting layer 13X_1 is higher than that of the light-emitting layer 13X_2, it can be said that the hole transport property of the light-emitting layer 13G is higher than that of the light-emitting layer 13B. In addition, 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 electron transport property of the light-emitting layer 13X_2 is higher than that of the light-emitting layer 13X_1, it can be said that the electron transport property of the light-emitting layer 13G is higher than that of the light-emitting layer 13B.

[0106] When the carrier transport property of the light-emitting layer 13R is high, the light-emitting device 10R preferably includes a carrier blocking layer in contact with the light-emitting layer 13R in order to control the recombination center in the light-emitting device 10R. In addition, when the carrier transport property of the light-emitting layer 13G is high, the light-emitting device 10G preferably includes a carrier blocking 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 blocking layer include a hole blocking layer and an electron blocking layer.

[0107] More specifically, when the hole transport property of the light-emitting layer 13R is high, the light-emitting device 10R preferably includes a hole blocking layer between the light-emitting layer 13R and the cathode 15, more preferably includes a hole blocking layer between the light-emitting layer 13R and the electron injection / transport layer 14, and further preferably includes a hole blocking layer in contact with the surface of the light-emitting layer 13R on the cathode 15 side. In addition, when the electron transport property of the light-emitting layer 13R is high, the light-emitting device 10R preferably includes an electron blocking layer between the light-emitting layer 13R and the anode 11R, more preferably includes an electron blocking layer between the light-emitting layer 13R and the hole injection / transport layer 12, and further preferably includes an electron blocking layer in contact with the surface of the light-emitting layer 13R on the anode 11R side. By adopting the above structure, carriers can be prevented from passing through the light-emitting layer 13R, so that recombination of carriers is likely to occur in the light-emitting layer 13R, thereby improving the light-emitting efficiency of the light-emitting device 10R.

[0108] In addition, when the hole transport property of the light-emitting layer 13G is high, the light-emitting device 10G preferably includes a hole blocking layer between the light-emitting layer 13G and the cathode 15, more preferably includes a hole blocking layer between the light-emitting layer 13G and the electron injection / transport layer 14, and further preferably includes a hole blocking layer in contact with the surface of the light-emitting layer 13G on the cathode 15 side. In addition, when the electron transport property of the light-emitting layer 13G is high, the light-emitting device 10G preferably includes an electron blocking layer between the light-emitting layer 13G and the anode 11G, more preferably includes an electron blocking layer between the light-emitting layer 13G and the hole injection / transport layer 12, and further preferably includes an electron blocking layer in contact with the surface of the light-emitting layer 13G on the anode 11G side. By adopting the above structure, carriers can be prevented from passing through the light-emitting layer 13G, so that recombination of carriers is likely to occur in the light-emitting layer 13G, thereby improving the light-emitting efficiency of the light-emitting device 10G.

[0109] When a carrier blocking layer is provided in the light emitting layer 13R, the light emitting layer 13G, etc., the carrier blocking layer may be a common layer or a layer formed in each device by vacuum evaporation using a metal mask.

[0110] Figure 4A An example is shown in which the light-emitting layer 13R includes an organic compound with a high hole-transporting property and the hole-blocking layer is a common layer. Figure 4A In the embodiment, the hole blocking layer 19 is a layer commonly used among the light emitting devices 10R, 10G, 10B, and 10X, and is provided in contact with the surface of the light emitting layer 13R on the cathode 15 side, the surface of the light emitting layer 13G on the cathode 15 side, the surface of the light emitting layer 13B on the cathode 15 side, and the surface of the light emitting layer 13X_2 on the cathode 15 side. In the case where the hole blocking layer is a common layer, it is not necessary to prepare a metal mask for manufacturing the hole blocking layer separately, so the manufacturing cost of the display device 100 can be reduced.

[0111] Figure 4B The example in which the light-emitting layer 13X_1 is a layer containing a light-emitting substance R, the light-emitting layer 13X_2 is a layer containing a light-emitting substance G, the light-emitting layer 13R contains an organic compound with a high hole-transporting property, and the hole-blocking layer is a layer formed by vacuum evaporation using a metal mask is shown. Figure 4B In the embodiment, the light emitting device 10R includes a hole blocking layer 19R in contact with the surface of the light emitting layer 13R on the cathode 15 side. Figure 4BAs shown, in the case where the light-emitting device 10R includes the hole blocking layer 19R, the light-emitting device 10X may also include the 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 contacts 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 evaporation method using a metal mask in the same process as the hole blocking layer 19R. In the case where the hole blocking layer 19X is formed by a vacuum evaporation 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 continuously formed without changing the metal mask after the light-emitting layer 13R and the light-emitting layer 13X_1 are formed. That is, there is no need to prepare metal masks for manufacturing the hole blocking layer 19R and the hole blocking layer 19X separately, so the manufacturing cost of the display device 100 can be reduced.

[0112] Figure 5A An example is shown in which the light-emitting layer 13R includes an organic compound with a high electron-transporting property and the electron blocking layer is a common layer. Figure 5A In the embodiment, the electron blocking layer 20 is a layer commonly used among the light emitting devices 10R, 10G, 10B, and 10X, and is provided in contact with the surface of the light emitting layer 13R on the anode 11R side, the surface of the light emitting layer 13G on the anode 11R side, the surface of the light emitting layer 13B on the anode 11R side, and the surface of the light emitting layer 13X_1 on the anode 11R side. In the case where the electron blocking layer is a common layer, it is not necessary to prepare a metal mask for manufacturing the electron blocking layer separately, so the manufacturing cost of the display device 100 can be reduced.

[0113] Figure 5B The example in which the light-emitting layer 13X_1 is a layer containing a light-emitting substance G, the light-emitting layer 13X_2 is a layer containing a light-emitting substance R, the light-emitting layer 13R contains an organic compound with a high electron-transporting property, and the electron blocking layer is a layer formed by vacuum deposition using a metal mask is shown. Figure 5B In the embodiment, the light emitting device 10R includes an electron blocking layer 20R in contact with the surface of the light emitting layer 13R on the anode 11R side. Figure 5BAs shown, in the case where the light-emitting device 10R includes an electron blocking layer 20R, the light-emitting device 10X may also include 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 contacts the surface of the light-emitting layer 13X_2 on the side of the anode 11X. In addition, the electron blocking layer 20X is a layer formed by a vacuum evaporation method using a metal mask in the same process as the electron blocking layer 20R. In the case where the electron blocking layer 20X is formed by a vacuum evaporation method using a metal mask in the same process as the electron blocking layer 20R, the light-emitting layer 13R and the light-emitting layer 13X_2 can be continuously formed without changing the metal mask after the electron blocking layer 20R and the electron blocking layer 20X are formed. That is, there is no need to prepare a metal mask for manufacturing the electron blocking layer 20R and the electron blocking layer 20X separately, so the manufacturing cost of the display device 100 can be reduced.

[0114] Figure 6 An example of forming a hole blocking layer and an electron blocking layer by vacuum evaporation using a metal mask is shown. Figure 6 In the embodiment, the light-emitting layer 13X_1 is a layer containing a light-emitting substance R, and the light-emitting layer 13X_2 is a layer containing a light-emitting substance G. Figure 6 In the embodiment, the light emitting device 10R includes a hole blocking layer 19R in contact with the surface of the light emitting layer 13R on the cathode 15 side. Furthermore, the light emitting device 10G includes an electron blocking layer 20G in contact with the surface of the light emitting layer 13G on the anode 11G side. Figure 6 As shown, in the case where the light-emitting device 10R includes the hole blocking layer 19R, the light-emitting device 10X may also include the 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 contacts the surface of the light-emitting layer 13X_1 on the cathode 15 side. In addition, the hole blocking layer 19X is a layer formed by vacuum evaporation using a metal mask in the same process as the hole blocking layer 19R. Furthermore, as Figure 6 As shown, in the case where the light-emitting device 10G includes the electron blocking layer 20G, the light-emitting device 10X may also include 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. In addition, the electron blocking layer 20X is a layer formed by a vacuum evaporation method using a metal mask in the same process as the electron blocking layer 20G. In this way, in order to control the carrier balance, a structure including both a hole blocking layer and an electron blocking layer may also be adopted.

[0115] In the case of forming the carrier blocking layer by a vacuum evaporation method using a metal mask, as Figure 4B , Figure 5B and Figure 6As shown, sometimes the carrier blocking layer is sandwiched between the light-emitting layer 13X_1 and the light-emitting layer 13X_2 of the light-emitting device 10X. In this structure, it is more preferred that the carrier blocking layer has bipolarity or a reduced thickness. The thickness of the carrier blocking layer when formed by a vacuum evaporation method using a metal mask is preferably greater than 1 nm and less than 20 nm, and more preferably greater than 3 nm and less than 10 nm. As a result, the luminous efficiency of the light-emitting device 10X can be improved.

[0116] Another method for solving the above problem is to sandwich the light-emitting layer S between two light-emitting layers L. By using this method, the recombination center easily overlaps with the light-emitting layer S, so that the light-emitting layer S can easily obtain energy.

[0117] Therefore, the light-emitting device 10X may also include a light-emitting layer having a stacked structure of a light-emitting layer 13X_1h, a light-emitting layer 13X_1e, and a light-emitting layer 13X_2 sandwiched between the light-emitting layer 13X_1h and the light-emitting layer 13X_1e. Note that the light-emitting layer 13X_1h and the light-emitting layer 13X_1e contain the same light-emitting substance, and the light-emitting layer 13X_2 contains a light-emitting substance different from the light-emitting layer 13X_1h and the light-emitting layer 13X_1e. For example, when the light-emitting layer 13X_1h and the light-emitting layer 13X_1e are layers containing the light-emitting substance R, and the light-emitting layer 13X_2 is a layer containing the light-emitting substance G or a layer containing the light-emitting substance B, the light-emitting layer 13X_2 can easily obtain energy, so it is preferred. In addition, for example, when the light-emitting layer 13X_1h and the light-emitting layer 13X_1e are layers containing the light-emitting substance G, and the light-emitting layer 13X_2 is a layer containing the light-emitting substance B, the light-emitting layer 13X_2 can easily obtain energy, so it is preferable. By adopting this structure, in the light-emitting device 10X, the light-emitting layer 13X_2, which is a layer containing a light-emitting substance with a shorter peak wavelength of the emission spectrum, is sandwiched between the light-emitting layer 13X_1h and the light-emitting layer 13X_1e, which are layers containing a light-emitting substance with a longer peak wavelength of the emission spectrum, so that the recombination center can be located in the light-emitting layer 13X_2. Therefore, good light emission can be obtained from all of the light-emitting layer 13X_1h, the light-emitting layer 13X_1e, and the light-emitting layer 13X_2.

[0118] The materials other than the luminescent substance of the luminescent layer 13X_1h and the luminescent layer 13X_1e may be different. For example, in the luminescent layer 13X_1h and the luminescent layer 13X_1e, the layer located on the anode 11X side may be a layer containing a hole transport material, and the layer located on the cathode 15 side may be a layer containing an electron transport material. In this way, the luminescent efficiency of the luminescent layer 13X_2 can be improved.

[0119] Figure 7An example is shown in which the light-emitting layer 13X_1h and the light-emitting layer 13X_1e are layers containing a light-emitting substance R, and the light-emitting layer 13X_2 is a layer containing a light-emitting substance G. Figure 7 In the embodiment, it is preferred that the light-emitting layer 13X_1h located on the anode 11X side contains a hole transport material, and the light-emitting layer 13X_1e located on the cathode 15 side contains an electron transport material.

[0120] In this case, the light-emitting layer 13X_1h is a layer formed by vacuum evaporation 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 vacuum evaporation using a metal mask in the same process as the light-emitting layer 13R_e. Therefore, it is preferred that the light-emitting layer 13R_h contains a hole transport material and the light-emitting layer 13R_e contains an electron transport material.

[0121] In addition, it can be said that Figure 7 In the structure shown, it is more preferable to use a hole transport material as the light-emitting layer 13R_h and the light-emitting layer 13X_1h, and to use an electron transport material as the light-emitting layer 13R_e and the light-emitting layer 13X_1e.

[0122] Furthermore, the light-emitting devices 10R, 10G, 10B, and 10X may be so-called tandem light-emitting devices in which an intermediate layer (charge generation layer) is provided between a plurality of light-emitting layers. Fig. 8A An example is shown in which the light emitting devices 10R, 10G, 10B, and 10X are tandem-type light emitting devices.

[0123] like Fig. 8AAs shown, 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 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, An intermediate layer 21 is arranged on the sub-injection / transport layer 14_a, a second hole injection / transport layer 12_b is arranged 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 arranged on the second hole injection / transport layer 12_b, a second electron injection / transport layer 14_b is arranged 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, a cathode 15 is formed on the second electron injection / transport layer 14_b, and series light-emitting devices 10R, 10G, 10B, 10X are arranged.

[0124] 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 preferably a common layer. In addition, the first light-emitting layer 13R_a, 13G_a, 13B_a, 13X_a, the second light-emitting layer 13R_b, 13G_b, 13B_b, 13X_b are preferably layers formed in each device by vacuum evaporation using a metal mask.

[0125] The tandem light emitting device 10R includes 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. In addition, the tandem light emitting device 10R includes 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. In addition, the first light-emitting layer 13R_a and the second light-emitting layer 13R_b both contain at least a light-emitting substance R.

[0126] The tandem light emitting device 10G includes a first light emitting layer 13G_a, a second light emitting layer 13G_b, and an intermediate layer 21 between the anode 11G and the 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. In addition, the tandem light emitting device 10G includes 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. In addition, the first light-emitting layer 13G_a and the second light-emitting layer 13G_b both contain at least a light-emitting substance G.

[0127] The tandem light emitting device 10B includes 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. In addition, the tandem light emitting device 10B includes 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. In addition, the first light-emitting layer 13B_a and the second light-emitting layer 13B_b both contain at least a light-emitting substance B.

[0128] 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 sequentially stacked. The first light-emitting layer 13X_a and the second light-emitting layer 13X_b contain different light-emitting substances.

[0129] The first light-emitting layer 13X_a is a layer formed by vacuum deposition using a metal mask in the same process as any of the first light-emitting layers 13R_a, 13G_a, and 13B_a. In addition, the second light-emitting layer 13X_b is a layer formed by vacuum deposition using a metal mask in the same process as any of the second light-emitting layers 13R_b, 13G_b, and 13B_b.

[0130] In a display device including a tandem light-emitting device, the light-emitting device 10X can be manufactured without adding a separate process and material for providing the light-emitting device 10X in the display device 100 , thereby reducing the cost of the display device 100 .

[0131] 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 preferably all contain an organic compound and an alkali metal or an alkaline earth metal, and more preferably all contain the same organic compound and the same alkali metal or alkaline earth metal.

[0132] The tandem light emitting device 10X may include a third light emitting layer 13X_c as a layer containing a light emitting substance 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. Figure 8B for Fig. 8A A modified example of the display device is shown, which includes a light-emitting device 10X provided with 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.

[0133] like Figure 8B As shown, when the third light-emitting layer 13X_c is disposed at a position in contact with the first light-emitting layer 13X_a, the third light-emitting layer 13X_c can be formed by vacuum evaporation using a metal mask in the same process as any of the first light-emitting layers 13R_a, 13G_a, and 13B_a. In addition, although not shown, when the third light-emitting layer 13X_c is disposed at a position in contact with the second light-emitting layer 13X_b, the third light-emitting layer 13X_c can be formed by vacuum evaporation using a metal mask in the same process as any of the second light-emitting layers 13R_b, 13G_b, and 13B_b.

[0134] When the third light-emitting layer 13X_c is provided, the light-emitting device 10X can be manufactured without adding any additional steps or materials, thereby reducing the cost of the display device 100 .

[0135] In addition, 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 emission intensity of the light emitting layer L that emits light with a long wavelength may be stronger than the light emission intensity of the light emitting layer S that emits light with a short wavelength, as in the single light emitting device 10X. Therefore, the stacking order of the stacked light emitting layers, the structure of each light emitting layer, the thickness of each light emitting layer, the electron blocking layer, the hole blocking layer, etc. described in the single light emitting device 10X can also be used for the tandem light emitting device 10X. It can be considered that when the third light emitting layer 13X_c is provided in contact with the first light emitting layer 13X_a, the intermediate layer 21 is equivalent to the cathode 15 in the single light emitting device 10X, and when the third light emitting layer 13X_c is provided in contact with the second light emitting layer 13X_b, the intermediate layer 21 is equivalent to the anode 11X in the single light emitting device 10X.

[0136] For example, Figure 8CAn example is shown in which a tandem light-emitting device 10X is provided with 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 is a layer formed by a vacuum evaporation method using a metal mask in the same process as the second light-emitting layer 13R_b, and is provided with a hole blocking layer 19. For example, in the case where the third light-emitting layer 13X_c and the second light-emitting layer 13R_b contain an organic compound with a high hole transport property, by providing the hole blocking layer 19 as described above, holes can be prevented from passing through the second light-emitting layer 13R_b in the tandem light-emitting device 10R, so that recombination of carriers is likely to occur in the light-emitting layer 13R, thereby improving the light-emitting efficiency of the light-emitting device 10R.

[0137] The other structures of the tandem light emitting device 10X are the same as those of the single light emitting device 10X, and thus description thereof is omitted. Also, the other structures of the display device including the tandem light emitting device are the same as those of the display device including the single light emitting device, and thus description thereof is omitted.

[0138] Although shown in Figure 1A In the display device 100 shown in the figure, the pixel 110 is constituted by four sub-pixels. However, in the display device according to one embodiment of the present invention, the pixel may be constituted by four or more sub-pixels. Fig. 9A A display device 100A is shown as a modified example of the display device 100. In the display device 100A, Fig. 9A The pixel 110 shown is composed of six sub-pixels, namely, a sub-pixel 50R, a sub-pixel 50G, a sub-pixel 50B, a sub-pixel 50Y, a sub-pixel 50C, and a sub-pixel 50M. The sub-pixels 50R, 50G, 50B, 50Y, 50C, and 50M respectively present light of different colors. As the sub-pixels 50R, 50G, and 50B, sub-pixels of red (R), green (G), and blue (B) can be cited. In addition, as the sub-pixels 50Y, 50C, and 50M, sub-pixels of yellow (Y), cyan (C), and magenta (M) can be cited.

[0139] Fig. 9B It is along Fig. 9A A cross-sectional view along the dotted line X3-X4.

[0140] In the display device 100A, the light-emitting devices 10R, 10G, 10B, 10Y, 10M, and 10C are provided on the layer 121, and a protective layer 122 is provided to cover these light-emitting devices. Furthermore, a substrate 124 is attached thereto via a resin layer 123. In addition, an insulating layer 125 is provided in the region between adjacent light-emitting devices.

[0141] The light emitting color of the light emitting device 10R, the light emitting color of the light emitting device 10G, the light emitting color of the light emitting device 10B, the light emitting color of the light emitting device 10Y, the light emitting color of the light emitting device 10M, and the light emitting color of the light emitting device 10C are different. 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.

[0142] like Fig. 9B As shown, in the display device 100A, an anode 11R, an anode 11G, an anode 11B, an anode 11Y, an anode 11M, and an anode 11C are provided on the layer 121, a 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, and a light-emitting layer 13R, a light-emitting layer 13G, a light-emitting layer 13B, a light-emitting layer 13Y_1, a light-emitting layer 13M_1, and a light-emitting layer 13C_1 are provided on the hole injection / transport layer 12. A light-emitting layer 13Y_2 is arranged on the light-emitting layer 13Y_1, a light-emitting layer 13M_2 is arranged on the light-emitting layer 13M_1, a light-emitting layer 13C_2 is arranged on the light-emitting layer 13C_1, an electron injection / transport layer 14 is arranged on the light-emitting layer 13R, the light-emitting layer 13G, the light-emitting layer 13B, the light-emitting layer 13Y_2, the light-emitting layer 13M_2 and the light-emitting layer 13C_2, and a cathode 15 is formed on the electron injection / transport layer 14, and light-emitting devices 10R, 10G, 10B, 10Y, 10M and 10C are arranged.

[0143] The light emitting device 10Y has the same structure 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 substance R and the other is a layer containing a light emitting substance G.

[0144] The light emitting device 10M has the same structure as the light emitting device 10X of magenta (M). That is, 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 substance R and the other is a layer containing a light emitting substance B.

[0145] The light emitting device 10C has the same structure 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 substance G and the other is a layer containing a light emitting substance B.

[0146] The other structures of the display device 100A are the same as those of the display device 100 , and thus description thereof is omitted.

[0147] By adopting a structure in which the pixel 110 includes six sub-pixels like the structure of the display device 100A, the number of color grayscale levels of the display device 100A can be increased.

[0148] The structure described in this embodiment can be used in combination with the structure described in other embodiment modes as appropriate.

[0149] Implementation Method 2

[0150] In this embodiment, reference is made to Fig. 9A The cross-sectional view of the display device 100A along the dashed line X3-X4 is shown in FIG. FIG. 10A to FIG. 12B A method for manufacturing the display device 100A, which is a display device according to one embodiment of the present invention, will be described.

[0151] The thin film (insulating film, semiconductor film, conductive film, etc.) constituting the display device can be formed by sputtering, chemical vapor deposition (CVD: Chemical Vapor Deposition) method, vacuum evaporation method, pulsed laser deposition (PLD: Pulsed Laser Deposition) method, atomic layer deposition (ALD: Atomic Layer Deposition) method, etc. As CVD methods, there are plasma enhanced chemical vapor deposition (PECVD: Plasma Enhanced CVD) method and thermal CVD method, etc. In addition, as one of the thermal CVD methods, there is metal organic chemical vapor deposition (MOCVD: Metal Organic CVD) method.

[0152] In addition, thin films (insulating films, semiconductor films, and conductive films, etc.) that constitute the display device can be formed by spin coating, dipping, spraying, inkjet, dispenser, screen printing, offset printing, doctor knife, slit coating, roller coating, curtain coating, doctor knife coating, and the like.

[0153] In particular, when manufacturing a light-emitting device, a vacuum process such as evaporation and a solution process such as spin coating and inkjet can be used. As the evaporation method, physical evaporation methods (PVD methods) such as sputtering, ion plating, ion beam evaporation, molecular beam evaporation, vacuum evaporation, and chemical evaporation (CVD methods) can be cited. In particular, the functional layer (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 evaporation (vacuum evaporation), coating (dip coating, dye coating, rod coating, spin coating, spray coating), printing (inkjet, screen printing (porcelain printing), offset printing (lithography), flexographic printing (letterpress printing), gravure printing or microcontact printing, etc.) and other methods.

[0154] In addition, when processing a thin film constituting a display device, it can be processed by photolithography, etc. Alternatively, the thin film can be processed by nanoimprinting, sandblasting, lift-off, etc. In addition, an island-shaped thin film can be directly formed by a deposition method using a shielding mask such as a metal mask.

[0155] There are two typical photolithography methods. One is to form a resist mask on a thin film to be processed, process the thin film by etching, etc., and then remove the resist mask. The other is to deposit a photosensitive thin film, then perform exposure and development to process the thin film into a desired shape.

[0156] In the photolithography method, as the light used for exposure, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm) or a mixture of these lights can be used. In addition, ultraviolet light, KrF laser or ArF laser, etc. can also be used. In addition, liquid immersion exposure technology can also be used for exposure. In addition, as the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays can also be used. In addition, instead of the light used for exposure, an electron beam can also be used. When extreme ultraviolet light, X-rays or electron beams are used, extremely fine processing can be performed, so it is preferred. Note that when exposure is performed by scanning with a light beam such as an electron beam, a photomask is not required.

[0157] As etching of the thin film, dry etching, wet etching, sand blasting, or the like can be used.

[0158] First, anodes 11R, 11G, 11B, 11Y, 11M, and 11C are formed on a layer 121 including transistors (not shown). Fig. 10A). First, a metal film is deposited 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, by removing the resist mask, the anodes 11R, 11G, 11B, 11Y, 11M, and 11C can be formed.

[0159] Next, the cover layer 121 and the insulating layer 125 at the ends of the anodes 11R, 11G, 11B, 11Y, 11M, and 11C are formed (see Fig. 10B ).

[0160] Next, a hole injection / transport layer 12 is formed on the anodes 11R, 11G, 11B, 11Y, 11M, 11C and the insulating layer 125 (see Fig. 10C ).

[0161] Next, light-emitting layers 13R, 13Y_1, and 13M_1 are formed on the hole injection / transport layer 12 and at positions overlapping the anodes 11R, 11Y, and 11M (see Fig. 10D ).

[0162] The light emitting layers 13R, 13Y_1, and 13M_1 are preferably formed in the same process by vacuum deposition using a metal mask. This eliminates the need for additional processes and materials for providing the light emitting layers 13Y_1 and 13M_1 in addition to the light emitting layer 13R, thereby reducing manufacturing costs.

[0163] Next, the light-emitting layers 13G and 13C_1 are formed on the hole injection / transport layer 12 and overlapped with the anodes 11G and 11C, and the light-emitting layer 13Y_2 is formed on the light-emitting layer 13Y_1 (see Fig.11A ).

[0164] The light-emitting layers 13G, 13Y_2, and 13C_1 are preferably formed in the same process by vacuum deposition using a metal mask. This eliminates the need for additional processes and materials for providing the light-emitting layers 13Y_2 and 13C_1 in addition to the light-emitting layer 13G, thereby reducing manufacturing costs.

[0165] Furthermore, the light-emitting layer 13B is formed on the hole injection / transport layer 12 and at a position overlapping with the anode 11B, the light-emitting layer 13M_2 is formed on the light-emitting layer 13M_1, and the light-emitting layer 13C_2 is formed on the light-emitting layer 13C_1 (see Fig. 11B ).

[0166] The light-emitting layers 13B, 13M_2, and 13C_2 are preferably formed in the same process by vacuum deposition using a metal mask. This eliminates the need for additional processes and materials for providing the light-emitting layers 13M_2 and 13C_2 in addition to the light-emitting layer 13G, thereby reducing manufacturing costs.

[0167] Note that in the above-mentioned manufacturing method, the light-emitting layer 13R is formed first, the light-emitting layer 13G is formed next, and the light-emitting layer 13B is formed last, but the order of forming the light-emitting layers 13R, 13G, and 13B is not limited to this. For example, the light-emitting layer 13B may be formed first, the light-emitting layer 13G may be formed next, and the light-emitting layer 13R may be formed last. In this case, the light-emitting layers 13M_1 and 13C_1 are preferably formed in the same process as the light-emitting layer 13B. In addition, the light-emitting layers 13Y_1 and 13C_2 are preferably formed in the same process as the light-emitting layer 13G. In addition, the light-emitting layers 13Y_2 and 13M_2 are preferably formed in the same process as the light-emitting layer 13R.

[0168] Next, an electron injection / transport layer 14 (see Fig. 11C ).

[0169] Next, by forming a cathode 15 ( Fig.11D ), light emitting devices 10R, 10G, 10B, 10Y, 10M, 10C are provided. The cathode 15 can be formed by, for example, sputtering or vacuum evaporation.

[0170] Then, a protective layer 122 ( Fig. 12A ).

[0171] Finally, by bonding the substrate 124 using the resin layer 123, a display device ( Fig. 12B ).

[0172] By manufacturing the display device of one embodiment of the present invention using the above 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 additional steps and materials, thereby reducing manufacturing costs.

[0173] The structure described in this embodiment can be used in combination with the structure described in other embodiment modes as appropriate.

[0174] Implementation 3

[0175] In this embodiment, refer to FIG. 13A to FIG. 13F The structure of a light-emitting device that can be used in a display device according to one embodiment of the present invention will be described.

[0176] <<Basic structure of light emitting device>>

[0177] The basic structure of a light emitting device is described. Fig.13AThe light-emitting device includes an EL layer (also referred to as an organic compound layer) having a light-emitting layer between a pair of electrodes. Specifically, the EL layer 103 is included between the first electrode 101 and the second electrode 102.

[0178] Fig. 13B It is shown that a pair of electrodes includes multiple (in Fig. 13B A light-emitting device having a stacked structure (tandem structure) including two EL layers (103a, 103b) and a charge generation layer 106 between the EL layers. A light-emitting device having a tandem structure can realize a highly efficient light-emitting device without changing the amount of current.

[0179] 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. Fig. 13B In the embodiment, when a voltage is applied so that the potential of the first electrode 101 is higher than that of the second electrode 102, the charge generation layer 106 injects electrons into the EL layer 103a and injects holes into the EL layer 103b.

[0180] In terms of light extraction efficiency, the charge generation layer 106 preferably has a light transmittance to visible light (specifically, the charge generation layer 106 has a visible light transmittance of 40% or more). The charge generation layer 106 can function even if its electrical conductivity is lower than that of the first electrode 101 and the second electrode 102 .

[0181] Fig. 13C The stacked structure of the EL layer 103 of the light-emitting device is shown. Note that in this case, the first electrode 101 is used as an anode and the second electrode 102 is used 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 sequentially stacked on the first electrode 101. As shown in Embodiment 1, the stacked structure of the hole injection layer 111 and the hole transport layer 112 may also be referred to as a hole injection / transport layer. In addition, as shown in Embodiment 1, the stacked structure of the electron transport layer 114 and the electron injection layer 115 may also be referred to as an electron injection / transport layer. In addition, as shown in Embodiment 1, the light-emitting layer 113 may also have a stacked structure in which a plurality of light-emitting layers having different light-emitting colors are in contact with each other. 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, 111 on the first electrode 101 as a cathode 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.

[0182] Fig.13D Show Fig. 13C A modified example of the stacked structure shown. In this case, the first electrode 101 is used as an anode and the second electrode 102 is used as a cathode. In this modified example, a case where a hole blocking layer and an electron blocking layer are included is shown. In other words, 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 stacked on the first electrode 101. The light-emitting layer 113 is located between the first electrode 101 and the second electrode 102. In addition, as shown in Embodiment 1, the light-emitting layer 113 may also have a stacked structure in which a plurality of light-emitting layers having different light-emitting colors are in contact with each other. In addition, 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. The electron injection layer 115 is located between the electron transport layer 114 and the second electrode 102. The electron blocking layer 116 is located between the hole transport layer 112 and the light emitting layer 113. The hole blocking layer 117 is located between the light emitting layer 113 and the electron transport layer 114.

[0183] The electron blocking layer 116 is provided, for example, to prevent electrons from the light-emitting layer 113 from passing through the first electrode 101. In addition, the hole blocking layer 117 is provided, for example, to prevent holes from the light-emitting layer 113 from passing through the second electrode 102.

[0184] Fig.13E The light emitting device shown is a light emitting device having Fig. 13B An example of a light-emitting device with a tandem structure shown, as shown in the accompanying drawings, has a structure in which two EL layers (103a, 103b) are stacked with a charge generation layer (106) sandwiched therebetween. The two EL layers (103a, 103b) respectively include light-emitting layers (113a, 113b), and the luminescent colors of each light-emitting layer can be freely combined. In addition, as shown in Embodiment 1, the light-emitting layers (113a, 113b) can also have a stacked structure in which multiple light-emitting layers with different luminescent colors are in contact with each other. With the help of a microcavity structure, light of different wavelengths (monochromatic light) can be extracted from each EL layer (103a, 103b). The details of the microcavity structure will be described in <<Specific structure of the light-emitting device>>. Therefore, it is not necessary to coat separately (for example, coating as R, G, and B) in order to obtain different luminescent colors. As a result, high resolution can be easily achieved. In addition, it can be combined with a coloring layer (color filter). In addition, the luminous intensity in the front direction with a specific wavelength can be enhanced, thereby achieving low power consumption.

[0185] Fig.13F The light emitting device shown is Fig. 13B An example of a light-emitting device having a tandem structure shown in the figure has a structure in which three EL layers (103a, 103b, 103c) are stacked with charge generation layers (106a, 106b) sandwiched therebetween. The three EL layers (103a, 103b, 103c) respectively include light-emitting layers (113a, 113b, 113c), and the light-emitting colors of each light-emitting layer can be freely combined. For example, the light-emitting layer 113a and the light-emitting layer 113c can exhibit blue, and the light-emitting layer 113b can exhibit any one of red, green, and yellow. In addition, the light-emitting layer 113a and the light-emitting layer 113c can exhibit red, and the light-emitting layer 113b can exhibit any one of blue, green, and yellow. In addition, as shown in Embodiment 1, the light-emitting layers (113a, 113b, 113c) can also have a stacked structure in which a plurality of light-emitting layers having different light-emitting colors are in contact with each other.

[0186] <<Specific structure of the light emitting device>>

[0187] Next, the specific structure of the light emitting device of one embodiment of the present invention is described. Fig.13E Note: Fig.13A , Fig. 13C and Fig.13D The structure of the EL layer of the single-type light-emitting device shown is the same as the structure of the EL layer of the tandem-type light-emitting device described below.

[0188] <First Electrode and Second Electrode>

[0189] As the material forming the first electrode 101 and the second electrode 102, if the functions of the above two electrodes can be satisfied, the following materials can be appropriately combined. For example, metals, alloys, conductive compounds and mixtures thereof can be appropriately used. Specifically, In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, In-W-Zn oxide can be cited. In addition to the above, 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), neodymium (Nd) and other metals and alloys appropriately combined therewith can also be cited. In addition to the above, elements belonging to Group 1 or Group 2 of the periodic table (for example, lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu), ytterbium (Yb), alloys appropriately combined therefrom, and graphene, etc. can be used.

[0190] exist Fig.13E In the light-emitting device shown, 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 sequentially stacked on the first electrode 101 by vacuum evaporation. 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 sequentially stacked on the charge generation layer 106 in the same manner as described above.

[0191] In addition, FIG. 13A to FIG. 13F In each of the light-emitting devices shown, by making the first electrode 101 a reflective electrode, making the second electrode 102 a semi-transmissive-semi-reflective electrode and adopting an optical microcavity resonator (microcavity) structure, the light obtained from the light-emitting layer 113 in the EL layer 103 can resonate between the above-mentioned electrodes, thereby enhancing the light emitted from the second electrode 102.

[0192] In the case where the first electrode 101 of the light-emitting device is a reflective electrode composed of a laminated structure of a reflective conductive material and a light-transmitting conductive material (transparent conductive film), optical adjustment can be performed by controlling the thickness of the transparent conductive film. Specifically, it is preferably adjusted in the following manner: when the wavelength of light obtained from the light-emitting layer 113 is λ, the optical distance (the product of thickness and refractive index) between the first electrode 101 and the second electrode 102 is mλ / 2 (note that m is an integer greater than 1) or a value close thereto.

[0193] 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 can be 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 can be obtained to (2m'+1)λ / 4 (note that m' is an integer greater than 1) or a value in the vicinity thereof. Note that the "light-emitting region" described here refers to the region where holes and electrons in the light-emitting layer 113 recombine.

[0194] By performing the above optical adjustment, the spectrum of specific monochromatic light that can be obtained from the light-emitting layer 113 can be narrowed, thereby obtaining light emission with good color purity.

[0195] Furthermore, in the above case, strictly speaking, the optical distance between the first electrode 101 and the second electrode 102 can be said to be the total thickness from the reflective region in the first electrode 101 to the reflective region in the second electrode 102. However, since it is difficult to accurately determine the positions of the reflective regions in the first electrode 101 and the second electrode 102, the above effect can be fully obtained by assuming that any position in the first electrode 101 and the second electrode 102 is a reflective region. Furthermore, strictly speaking, the optical distance between the first electrode 101 and the light-emitting layer that can obtain the desired light can be said to be the optical distance between the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer that can obtain the desired light. However, since it is difficult to accurately determine the positions of the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer that can obtain the desired light, the above effect can be fully obtained by assuming that any position in the first electrode 101 is a reflective region and any position in the light-emitting layer that can obtain the desired light is a light-emitting region.

[0196] In addition, in the light-emitting device of one embodiment of the present invention, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (transparent electrode, semi-transmitting-semi-reflecting electrode, etc.). In the case where the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. In addition, in the case where the electrode is a semi-transmitting-semi-reflecting electrode, the visible light reflectance of the semi-transmitting-semi-reflecting electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. In addition, the resistivity of these electrodes is preferably 1×10 -2 Ωcm or less.

[0197] In the light-emitting device of 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 reflective electrode has a visible light reflectivity of 40% to 100%, preferably 70% to 100%. In addition, the resistivity of the electrode is preferably 1×10 -2 Ωcm or less.

[0198] <Hole Injection Layer>

[0199] The hole injection layer (111, 111a, 111b) is a layer for injecting holes from the anode first electrode 101 and the charge generation layer (106, 106a, 106b) into the EL layer (103, 103a, 103b), and contains an organic acceptor material and a material with high hole injection properties.

[0200] The organic acceptor material can generate holes in the organic compound by charge separation with other organic compounds whose HOMO energy level is close to the LUMO energy level. Therefore, compounds having an electron-withdrawing group (halogen or cyano) such as quinone dimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatriphenylene derivatives can be used as organic acceptor materials. 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-dicyanomethylidene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile, etc. can be used. Among organic acceptor materials, compounds such as HAT-CN, etc., in which electron-withdrawing groups are bonded to fused aromatic rings having multiple heteroatoms, have high acceptability and the film quality has thermal stability, so they are particularly preferred. In addition, [3] axial ene derivatives including electron-withdrawing groups (especially halogen groups such as fluorine groups or cyano groups) have very high electron acceptability and are therefore preferred. Specifically, α, α', α"-1,2,3-cyclopropane trimethylene tris[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α, α', α"-1,2,3-cyclopropane trimethylene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α, α', α"-1,2,3-cyclopropane trimethylene tris[2,3,4,5,6-pentafluorophenylacetonitrile], etc. can be used.

[0201] As a material with high hole injection property, oxides of metals 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, etc.) can be used. Specifically, molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide can be cited. Among them, molybdenum oxide is particularly stable in the atmosphere, has low hygroscopicity, and is easy to handle, so it is preferred. In addition, perylenetetracarboxylic 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-perylenetetracarboxylic acid diimide (abbreviation: PTCDI), 3,4,9,10-perylenetetracarboxylic acid-bis-benzimidazole (abbreviation: PTCBI), (C 60 -Ih )[5,6]fullerene (abbreviated as: C 60 )、(C 70 -D 5h )[5,6]fullerene (abbreviated as: C 70 ), organic compounds such as phthalocyanine (abbreviation: H2Pc), copper phthalocyanine (abbreviation: CuPc), zinc phthalocyanine (abbreviation: ZnPc), cobalt phthalocyanine (abbreviation: CoPc), iron phthalocyanine (abbreviation: FePc), tin phthalocyanine (abbreviation: SnPc), tin phthalocyanine oxide (abbreviation: SnOPc), titanium phthalocyanine oxide (abbreviation: TiOPc), vanadium phthalocyanine oxide (abbreviation: VOPc), etc., containing copper, zinc, cobalt, iron, chromium, nickel, etc., and their derivatives, or metal complexes containing metal-oxygen bonds and aromatic ligands. In addition, particularly preferred are phthalocyanine metal complexes such as CuPc or ZnPc, or 2,3,8,9,14,15-hexafluorobisquinoxalino[2,3-a:2',3'-c]phenazine. In particular, CuPc and ZnPc are inexpensive and have good properties, so they are preferred. Furthermore, ZnPc has a small diffusion coefficient with respect to silicon, and the possibility of the metal diffusing into the semiconductor and affecting the semiconductor characteristics is reduced. Therefore, ZnPc is particularly suitable for use in display devices using silicon semiconductors.

[0202] In addition to the above materials, the following low molecular weight aromatic amine compounds can be used, such as 4,4',4"-tris(N,N-diphenylamino)triphenylamine (abbreviated as TDATA), 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviated as MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis-[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl benzene (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), etc.

[0203] In addition, a polymer compound (oligomer, dendrimer or polymer, etc.) can be used, such as poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD), etc. Alternatively, a polymer compound to which an acid is added, such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS), polyaniline / polystyrene sulfonic acid (abbreviated as PAni / PSS), etc. can also be used.

[0204] As a material with high hole injection properties, a mixed material containing a hole transport material and the above-mentioned organic acceptor material (electron acceptor material) can also be used. In this case, the organic acceptor material extracts electrons from the hole transport material to generate holes in the hole injection layer 111, and the holes are injected into the light-emitting layer 113 through the hole transport layer 112. In addition, the hole injection layer 111 can be a single layer composed of a mixed material containing a hole transport material and an organic acceptor material (electron acceptor material), or a stack of layers formed using a hole transport material and an organic acceptor material (electron acceptor material) respectively.

[0205] As a hole transport material, it is preferable to use a hole transport material having a hole mobility of 1×10 -6 cm 2 In addition, any substance other than the above may be used as long as it has a higher hole-transporting property than an electron-transporting property.

[0206] As the hole transport material, preferably used are hole transport materials such as compounds having a π-electron-rich heteroaromatic ring (for example, carbazole derivatives, furan derivatives, or thiophene derivatives) and aromatic amines (organic compounds containing an aromatic amine skeleton).

[0207] Examples of the carbazole derivative (organic compound having a carbazole ring) include bicarbazole derivatives (eg, 3,3′-bicarbazole derivatives) and aromatic amines having a carbazole group.

[0208] As the above-mentioned bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives), specifically, there can be mentioned 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as: BismBPCz), 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviated as: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as: βNCCP), etc.

[0209] In addition, as the aromatic amine having the above-mentioned carbazole group, specifically, 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviation: PCBiF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-bis(9,9-dimethyl-9H-fluorene-2-yl)amine (abbreviation: PCBiF), PCBFF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-diphenyl-9H-fluorene-4-amine, N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-(9,9-diphenyl-9H-fluorene-2-yl)-9,9-diphenyl-9H-fluorene-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-diphenyl-9H-fluorene-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-diphenyl-9H-fluorene -4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi(9H-fluorene)-2-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi(9H-fluorene)-4-amine, N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-(1,1':3',1"-terphenyl-4-yl)-9,9-dimethylbenzene-9H-fluorene-2-amine, N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-(1,1':4',1"-terphenyl-4-yl)- 9,9-Dimethylbenzene-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-(1,1':3',1"-terphenyl-4-yl)-9,9-dimethylbenzene-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-(1,1':4',1"-terphenyl-4-yl)-9,9-dimethylbenzene-9H-fluoren-4-amine, 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl)amine (abbreviated as: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviated as: PCA2B), N,N',N"-triphenyl-N,N',N"-tri(9-phenylcarbazole-3-yl)benzene-1,3,5-triamine (abbreviated as: PCA3B), 9,9- dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenyl Carbazole (abbreviated as PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino] -9-phenylcarbazole (abbreviated as PCzTPN2), N-(9,9-spirobi[9H-fluorene]-2-yl)-N,9-diphenylcarbazole-3-amine (abbreviated as PCASF), N-(4-biphenyl)-4-(carbazole-9-yl)phenylaniline (abbreviated as YGA1BP), N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviated as YGA2F), 4,4',4"-tris(carbazole-9-yl)triphenylamine (abbreviated as TCTA), etc.

[0210] Note that as carbazole derivatives, in addition to the above, 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'-bis(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), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), etc. can also be mentioned.

[0211] Specific examples of the above-mentioned furan derivatives (organic compounds having a furan ring) include 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and the like.

[0212] Specific examples of the above-mentioned thiophene derivatives (organic compounds having a thiophene ring) include 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), which are organic compounds having a thiophene ring.

[0213] Specific examples of the aromatic amines 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), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluorene-2-yl)triphenylamine (abbreviation: mBPAFLP), and N-(9,9-dimethyl-9H-fluorene-2-yl)triphenylamine. -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-fluoren]-2,7-diamine (abbreviation: DPA2SF), 4,4',4"-tri[N-(1-naphthyl)-N-phenylamino]tri Aniline (abbreviation: 1'-TNATA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]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-benzidine (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 (abbreviated as: BBAαNβNB-03), 4,4'-diphenyl-4"-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviated as: BBAPβNB-03), 4,4'-diphenyl-4"-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B), 4,4'-diphenyl-4"-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B-03), 4,4'-diphenyl-4"-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviated as: BBAβNαNB), 4,4'-diphenyl-4"-(5;2'-binaphthyl-1-yl)triphenylamine amine (abbreviated as: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviated as: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviated as: αNBB1BP), 4,4'-diphenyl-4"-[4'-(carbazol-9-yl)biphenyl triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tri(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-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-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfB NBN), 4-phenyl-4'-[4-(9-phenylfluorene-9-yl)phenyl]triphenylamine (abbreviated as: BPAFLBi), N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-3-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-1-amine, etc. ,

[0214] In addition, as a hole transport material, a polymer compound (oligomer, dendrimer, polymer, etc.) can be used, such as poly (N-vinyl carbazole) (abbreviated as: PVK), poly (4-vinyl triphenylamine) (abbreviated as: PVTPA), poly [N- (4-{N'-[4-(4-diphenylamino) phenyl] phenyl-N'-phenylamino} phenyl) methacrylamide] (abbreviated as: PTPDMA), poly [N, N'-bis (4-butylphenyl) -N, N'-bis (phenyl) benzidine] (abbreviated as: Poly-TPD), etc. Alternatively, a polymer compound to which an acid is added, such as poly (3, 4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as: PEDOT / PSS) or polyaniline / polystyrene sulfonic acid (abbreviated as: PAni / PSS), etc. can also be used.

[0215] Note that the hole transport material is not limited to the above materials, and a combination of one or more of various known materials can be used as the hole transport material.

[0216] Note that the hole injection layer (111, 111a, 111b) can be formed by various known film-forming methods, for example, by vacuum evaporation.

[0217] <Hole Transport Layer>

[0218] The hole transport layer (112, 112a, 112b) is a layer that transports holes injected from the hole injection layer (111, 111a, 111b) from the first electrode 101 to the light-emitting layer (113, 113a, 113b). In addition, the hole transport layer (112, 112a, 112b) is a layer containing a hole transport material. Therefore, as the hole transport layer (112, 112a, 112b), a hole transport material that can be used for the hole injection layer (111, 111a, 111b) can be used.

[0219] Note that in a light-emitting device of one embodiment of the present invention, the same organic compound as that of the hole transport layer (112, 112a, 112b) can be used for the light-emitting layer (113, 113a, 113b). When the same organic compound is used for the hole transport layer (112, 112a, 112b) and the light-emitting layer (113, 113a, 113b), holes can be efficiently transported from the hole transport layer (112, 112a, 112b) to the light-emitting layer (113, 113a, 113b), which is preferred.

[0220] <Electron blocking layer>

[0221] The electron blocking layer 116 is provided, for example, to prevent electrons from passing through the first electrode 101 side from the light-emitting layer 113. The electron blocking layer 116 preferably uses a material having high hole transport properties, low electron transport properties and a high LUMO energy level. Preferably, a material whose LUMO energy level is higher than the LUMO energy level of the material constituting the light-emitting layer (at least the main material) is selected from the substances listed above as the materials that can be used as the hole transport layer 112, and preferably a material having a LUMO energy level higher than 0.30ev is used to form the electron blocking layer. Note that the electron blocking layer transports holes and can therefore also be regarded as a part of the hole transport layer 112.

[0222] <Luminous Layer>

[0223] The light-emitting layer (113, 113a, 113b) is a layer containing a light-emitting substance. For the light-emitting substance that can be used for the light-emitting layer (113, 113a, 113b), substances that emit light in blue, purple, blue-purple, green, yellow-green, yellow, orange, red, etc. can be appropriately used. In addition, when a plurality of light-emitting layers are included, by using different light-emitting substances in each light-emitting layer, a structure that emits different light-emitting colors can be obtained (for example, light-emitting colors that are in a complementary color relationship can be combined to obtain white light). In addition, when a plurality of light-emitting layers are included, each light-emitting layer can also exhibit the same color. When multiple light-emitting layers with the same light-emitting color are stacked, reliability can sometimes be improved compared to a single layer. Furthermore, a stacked structure in which one light-emitting layer contains different light-emitting substances can also be adopted.

[0224] Furthermore, the light-emitting layer (113, 113a, 113b) may contain one or more organic compounds (host material, etc.) in addition to the light-emitting substance (guest material).

[0225] Note that when multiple host materials are used in the light-emitting layer (113, 113a, 113b), as the newly added second host material, it is preferred to use a substance having an energy gap larger than the energy gaps of the existing guest material and the first host material. In addition, it is preferred that the lowest singlet excitation energy level (S1 energy level) of the second host material is higher than the S1 energy level of the first host material, and the lowest triplet excitation energy level (T1 energy level) of the second host material is higher than the T1 energy level of the guest material. In addition, it is preferred that the lowest triplet excitation energy level (T1 energy level) of the second host material is higher than the T1 energy level of the first host material. By adopting the above structure, an excimer complex can be formed by two host materials. Note that in order to efficiently form an excimer complex, it is particularly preferred to combine a compound that easily receives holes (hole transport material) and a compound that easily receives electrons (electron transport material). In addition, by adopting the above structure, high efficiency, low voltage and long life can be achieved at the same time.

[0226] Note that as the organic compound used as the above-mentioned host material (including the first host material and the second host material), as long as the conditions for the host material used for the light-emitting layer are met, an organic compound such as a hole transport material that can be used for the above-mentioned hole transport layer (112, 112a, 112b) or an electron transport material that can be used for the electron transport layer (114, 114a, 114b) described later can be used, and an exciplex formed by a plurality of organic compounds (the above-mentioned first host material and the second host material) can also be used. In addition, an exciplex formed by a plurality of organic compounds in an excited state has the function of a thermally activated delayed fluorescence (TADF) material that can convert triplet excitation energy into singlet excitation energy because the difference between the S1 energy level and the T1 energy level is extremely small. As a combination of a plurality of organic compounds that form an exciplex, for example, it is preferred that one has a π-electron-deficient heteroaromatic ring and the other has a π-electron-rich heteroaromatic ring. Furthermore, as one of the combinations that form an exciplex, a phosphorescent substance such as an iridium, rhodium or platinum-based organic metal complex or metal complex may be used.

[0227] There is no particular limitation on the luminescent material that can be used in the luminescent layer (113, 113a, 113b), and a luminescent material that converts singlet excitation energy into light in the visible light region or a luminescent material that converts triplet excitation energy into light in the visible light region can be used.

[0228] <<Luminescent material that converts singlet excitation energy into luminescence>>

[0229] As the luminescent material that can be used for the luminescent layer (113, 113a, 113b) and converts the singlet excitation energy into luminescence, the following fluorescent emitting materials (fluorescent luminescent materials) can be cited. 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, naphthalene derivatives, etc. can be cited. In particular, pyrene derivatives are 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.

[0230] In addition, 5,6-bis[4-(10-phenyl-9-anthracenyl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthracenyl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenyl-4,4'-diphenylethylenediamine (abbreviation: Y GA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthracenyl)triphenylamine (abbreviated as: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthracenyl)triphenylamine (abbreviated as: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviated as: PCAPA), 4-(10-phenyl triphenylamine (abbreviated as: PCBAPA), 4-[4-(10-phenyl-9-anthracenyl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBAPBA), perylene, 2,5,8,11-tetra-(tert-butyl) perylene (abbreviated as: TBP), N,N"-(2-tert-butylanthracene-9,10-diyldiphenylamine -4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviated as: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviated as: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthracenyl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 2DPAPPA), etc.

[0231] In addition, N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-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-carbazole-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N, 9-Triphenylanthracen-9-amine (abbreviated as DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviated as DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenylnaphthacene (abbreviated as BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malononitrile (abbreviated as DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as DCM2), N,N,N',N'-tetra(4- methylphenyl)tetracene-5,11-diamine (abbreviated as p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviated as p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as DCJTI), )vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malononitrile (abbreviated as: 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)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as: BisDCJTM), 1,6BnfAPrn-03, 3,10-bis[N-(9-phenyl-9H-carbazole-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, and 1,6BnfAPrn-03 can be used. ;

[0232] <<Luminescent material that converts triplet excitation energy into luminescence>>

[0233] Next, as a light-emitting substance that converts triplet excitation energy into light emission and can be used for the light-emitting layer 113, for example, a substance that emits phosphorescence (phosphorescent substance) or a TADF material that exhibits thermally activated delayed fluorescence can be mentioned.

[0234] Phosphorescent materials refer to compounds that exhibit phosphorescence but no fluorescence at any temperature in the temperature range (i.e., 77K or more and 313K or less) above low temperature (e.g., 77K or more and 313K or less) below room temperature. The phosphorescent material preferably contains a metal element with a large spin-orbit interaction, and an organic metal complex, a metal complex (platinum complex), a rare earth metal complex, etc. can be used. Specifically, it is preferred to contain a transition metal element, and it is particularly preferred to contain a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir) or platinum (Pt)), and it is particularly preferred to contain iridium. Iridium can increase the probability of direct transition between the singlet ground state and the triplet excited state, so it is preferred.

[0235] <<Phosphorescent substances (450nm and above and 570nm and below: blue or green)>>

[0236] Examples of phosphorescent substances that emit blue or green light and have an emission spectrum with a peak wavelength of 450 nm to 570 nm include the following substances.

[0237] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Mptz)3]), tris[4-(3- organic metal complexes having a 4H-triazole ring, such as tris[3-(5-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(iPrptz-3b)3]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(iPr5btz)3]); tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(iPr5btz)3]); [1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviated as [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me)3]); and bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviated as FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ]iridium(III) picolinate (abbreviated as FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2’ Iridium(III) picolinate (abbreviated as [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ]Organometallic complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium (III) acetylacetonate (abbreviation: FIr(acac)).

[0238] <<Phosphorescent substances (495nm and above and 590nm and below: green or yellow)>>

[0239] Examples of phosphorescent substances that emit green or yellow light and have an emission spectrum with a peak wavelength of 495 nm to 590 nm include the following substances.

[0240] For example, tris(4-methyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonate)bis(6-methyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonate)bis[6-(2-norbornyl)-4-phenylpyrimidinyl]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonate)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinyl]iridium(III) (abbreviation: [Ir(mpmppm)2( acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviated as [Ir(dmppm-dmp)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinyl)iridium(III) (abbreviated as [Ir(dppm)2(acac)]), etc.; (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-iPr)2(acac)]), etc.; tri(2-phenylpyridinium-N,C 2’ )iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinium-N,C 2’ )iridium(III)acetylacetonate (abbreviated as [Ir(ppy)2(acac)]), bis(benzo[h]quinoline)iridium(III)acetylacetonate (abbreviated as [Ir(bzq)2(acac)]), tris(benzo[h]quinoline)iridium(III) (abbreviated as [Ir(bzq)3]), tris(2-phenylquinoline-N,C 2’ )iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinoline-N,C 2’)iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-phenyl-2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC], [2-d3-methyl-8-(2-pyridyl-κN)benzofuran[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN 2 )phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridyl-κN]benzofurano[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl Organometallic iridium complexes having a pyridine ring, such as [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(ppy)2(mdppy)), ... 2’ ) iridium (III) acetylacetonate (abbreviated as [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridine-N,C 2’ Iridium(III) acetylacetonate (abbreviated as [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazole-N,C 2’ ) organic metal complexes such as iridium (III) acetylacetonate (abbreviated as [Ir(bt)2(acac)]), and rare earth metal complexes such as tris(acetylacetonate)(monophenanthroline)terbium (III) (abbreviated as [Tb(acac)3(Phen)]).

[0241] <<Phosphorescent substances (570nm and above and 750nm and below: yellow or red)>>

[0242] Examples of phosphorescent substances that exhibit yellow or red light and have an emission spectrum with a peak wavelength of 570 nm to 750 nm include the following substances.

[0243] For example, (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinyl]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinyl](dipivaloylmethane)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), (dipivaloylmethane)bis[4,6-di(naphthalene-1-yl)pyrimidinyl]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), etc. can be mentioned. Organic metal complexes with pyrimidine rings; (acetylacetonato)bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazine)(dipivaloylmethane)iridium(III) (abbreviated as [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-heptanedione-κ 2 O, O') iridium (III) (abbreviated as [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-heptanedione-κ 2 O, O') iridium (III) (abbreviated as [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-heptanedione-κ 2 O, 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’ ]iridium (III) (abbreviated as [Ir(dpq)2(acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium (III) (abbreviated as [Ir(Fdpq)2(acac)]) and other organic metal complexes having a pyrazine ring; tris(1-phenylisoquinoline-N,C 2’ )iridium(III) (abbreviated as [Ir(piq)3]), bis(1-phenylisoquinoline-N,C2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]) and bis[4,6-dimethyl-2-(quinolin-2-yl-κN)phenyl-κC](2,4-pentanedionato-κ 2 O,O’)iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]) and other organometallic complexes having a pyridine ring; platinum complexes such as platinum(II) 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin (abbreviation: [PtOEP]); or 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-thienoyl)-3,3,3-trifluoroacetone](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]).

[0244] <<TADF material>>

[0245] In addition, the following materials can be used as TADF materials. A TADF material refers to a material in which the energy difference between the S1 energy level and the T1 energy level is small (preferably 0.20 eV or less) and can convert the triplet excited state into the singlet excited state (reverse intersystem crossing) by using minute thermal energy and emit light (fluorescence) from the singlet excited state with high efficiency. The conditions for obtaining thermally activated delayed fluorescence with high efficiency are as follows: the energy difference between the triplet excited energy level and the singlet excited energy level is 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 emitted by the TADF material refers to light emission having the same spectrum as ordinary fluorescence but a very long lifetime. Its lifetime is 1×10 -6 seconds or more or 1×10 -3 seconds or more.

[0246] In addition, the TADF material can be used as an electron transport material, a hole transport material, or a host material.

[0247] As TADF materials, for example, fullerene and its derivatives, acridine derivatives such as prussicin, eosin, etc. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In) or palladium (Pd) can be cited. As metal-containing porphyrins, for example, protoporphyrin-tin fluoride complex (abbreviated as: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviated as: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviated as: SnF2(HematoIX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviated as: SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviated as: SnF2(OEP)), protoporphyrin-tin fluoride complex (abbreviated as: SnF2(Etio I)) and octaethylporphyrin-platinum chloride complex (abbreviated as: PtCl2OEP) can be mentioned.

[0248] [Chemical formula 1]

[0249]

[0250] In addition to the above, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(1 0H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), dimethoxybenzylamine [4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracen]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)benzofurano[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9'-phenyl -3,3'-biphenyl-9H-carbazole-9-yl)phenyl]benzofurano[3,2-d]pyrimidine (abbreviated as: 4PCCzPBfpm), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-biphenyl-9H-carbazole (abbreviated as: mPCCzPTzn-02), and other heteroaromatic compounds having π-electron-rich heteroaromatic compounds and π-electron-deficient heteroaromatic compounds.

[0251] In addition, in the substance in which the π-electron-rich heteroaromatic compound and the π-electron-deficient heteroaromatic compound are directly bonded, 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 becomes small, so it is particularly preferred. In addition, as a TADF material, a TADF material (TADF100) in which the singlet excited state and the triplet excited state are in thermal equilibrium can also be used. This TADF material has a short luminescence lifetime (excitation lifetime), so it can suppress the efficiency reduction in the high brightness area of ​​the light-emitting device.

[0252] [Chemical formula 2]

[0253]

[0254] In addition to the above, as a material having the function of converting triplet excitation energy into luminescence, a nanostructure of a transition metal compound having a perovskite structure can be cited. Metal halide perovskite nanostructures are particularly preferred. As the nanostructure, nanoparticles and nanorods are preferred.

[0255] In the light-emitting layer (113, 113a, 113b, 113c), as an organic compound (host material, etc.) used in combination with the above-mentioned light-emitting substance (guest material), one or more substances having a larger energy gap than the light-emitting substance (guest material) can be used.

[0256] <<Fluorescent host material>>

[0257] When the light-emitting material used for the light-emitting layer (113, 113a, 113b, 113c) is a fluorescent light-emitting material, as an organic compound (host material) used in combination with the light-emitting material, an organic compound having a large energy level in a singlet excited state and a small energy level in a triplet excited state or an organic compound having a high fluorescence quantum yield is preferably used. Therefore, as long as the organic compound satisfies the above conditions, the hole transport material (described above) and the electron transport material (described later) shown in this embodiment mode can be used.

[0258] Although part of the content is repeated in the above specific examples, from the viewpoint of preferably using in combination with a light-emitting substance (fluorescent light-emitting substance), examples of the organic compound (host material) include anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, (chrysene) derivatives, dibenzo[g,p] Derivatives and other fused polycyclic aromatic compounds.

[0259] Specific examples of organic compounds (host materials) preferably used in combination with fluorescent substances include 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as DPCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9,10-diphenylanthracene (abbreviated as DPAnth), N,N-diphenyl-9-[4-( 10-phenyl-9-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviated as: CzA1PA), 4-(10-phenyl-9-anthracenyl)triphenylamine (abbreviated as: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthracenyl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviated as: PCAPBA), N-(9,10-diphenyl-2-anthracenyl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as: 2PCAPA), 6,12-dimethoxy-5,11-diphenyl N,N,N',N',N",N",N"',N"'-octaphenyldibenzo[g,p] -2,7,10,15-tetramine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthryl)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-anthracen-yl)-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: α, β-ADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracen-yl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[4-(1-naphthyl)phenyl]anthracene (abbreviation: αN-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-(1-naphthyl)phenyl]anthracene (abbreviation: βN-mαNPAnth), )-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), 9,9'-bianthracene (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)phenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)phenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrene)benzene (abbreviation: TPB3), 5,12-diphenyl tetracene, 5,12-bis(biphenyl-2-yl) tetracene, etc.

[0260] <<Phosphorescent host material>>

[0261] When the light-emitting material used in the light-emitting layer (113, 113a, 113b, 113c) is a phosphorescent light-emitting material, an organic compound (host material) used in combination with the light-emitting material may be selected whose triplet excitation energy (energy difference between the ground state and the triplet excited state) is greater than the triplet excitation energy of the light-emitting material. Note that when a plurality of organic compounds (e.g., a first host material and a second host material (or an auxiliary material)) are used in combination with the light-emitting material in order to form an exciplex, it is preferable to use these plurality of organic compounds mixed with the phosphorescent light-emitting material.

[0262] By adopting such a structure, light emission by ExTET (Exciplex-Triplet Energy Transfer) utilizing energy transfer from an exciplex to a luminescent substance can be efficiently obtained. As a combination of multiple organic compounds, a combination that easily forms an exciplex is preferably used, and a combination of a compound that easily accepts holes (hole transport material) and a compound that easily accepts electrons (electron transport material) is particularly preferred.

[0263] Although part of the content is repeated in the above specific examples, from the viewpoint of the preferred combination with the light-emitting substance (phosphorescent light-emitting substance), examples of the organic compound (host material, auxiliary material) 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 (organic compounds having a dibenzofuran ring), and the like. Organisms (organic compounds having a benzimidazole 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), furanodiazine derivatives (organic compounds having a furanodiazine ring), zinc and aluminum metal complexes, etc.

[0264] Note that among the above organic compounds, specific examples of aromatic amines and carbazole derivatives as organic compounds having a high hole-transporting property include the same materials as the specific examples of the above hole-transporting materials, and these materials are preferably used as the host material.

[0265] Specific examples of dibenzothiophene derivatives and dibenzofuran derivatives as organic compounds having high hole transport properties among the above organic compounds include 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), DBT3P-II, and II, 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as: DBTFLP-IV), 4-[3-(triphenyl-2-yl)phenyl]dibenzothiophene (abbreviated as: mDBTPTp-II), etc. These materials are preferably used as the main materials.

[0266] In addition, preferred host materials include metal complexes having oxazolyl ligands and thiazole ligands, such as bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ).

[0267] In addition, among the above-mentioned organic compounds, specific examples of oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, phenanthroline derivatives, etc. as organic compounds with high electron transport properties include 2-(4-biphenyl)-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-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2 Organic compounds containing a heteroaromatic ring having a polyazole ring, such as 4-triazole (abbreviation: TAZ), 2,2',2"-(1,3,5-phenyltriyl)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), bathophenanthroline (abbreviation: Bphen), bathocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl- 1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-I II), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as: 7mDBTPDBq-II) and 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviated as: ZADN), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mpPCBPDBq) organic compounds containing heteroaromatic rings having dibenzoquinoxaline rings, etc., and these materials are preferably used as the main material.

[0268] Among the above-mentioned organic compounds, specific examples of pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, and pyridazine derivatives), triazine derivatives, and furanodiazine derivatives as organic compounds with high electron transport properties include 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine) (abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl] phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviated as mPCCzPTzn-02), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy), 1,3,5-tris[3-(3-pyridine)phenyl]benzene (abbreviated as TmPyPB), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviated as 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]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), : 9pmDBtBPNfpr), 11-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviated as: 11mDBtBPPnfpr), 11-[3'-(dibenzothiophene-4-yl)biphenyl-4-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 11-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 12-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviated as 12PCCzPnfpr), 9-[3'-(9-phenyl-9H-carbazole-3-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9pmPCBPNfpr), 9-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9PCCzNfpr), 10-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 10PCCzNfpr), 9-[3'-(6-phenylbenzo[b]naphtho [1,2-d]furan-8-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mBnfBPNfpr), 9-{3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), 9-[3'-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr-02), 9-[3-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)phenyl}naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), ] naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as: 9mPCCzPNfpr), 9-[3'-(2,8-diphenyldibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine, 11-[3'-(2,8-diphenyldibenzothiophene-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviated as: mINc(II)PTzn), 2-[3'-(triphenylene-2 9-(4,6-diphenyl-1,3,5-triazine)-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviated as BP-SFTzn), 2,6-bis(4-naphth-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',Organic compounds containing heteroaromatic rings having diazine rings, such as 1-(1-triphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), and 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), are preferably used as the host material.

[0269] Among the above-mentioned organic compounds, specific examples of metal complexes of organic compounds with high electron transport properties include: zinc or aluminum metal complexes of tris(8-hydroxyquinoline)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviation: BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviation: Znq); metal complexes having a quinoline ring or a benzoquinoline ring, etc. These materials are preferably used as the main material.

[0270] In addition, as preferred main materials, polymer compounds such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used.

[0271] Furthermore, bipolar 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviation: PCCzQz), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indole, which are organic compounds with high hole transport properties and high electron transport properties, Organic compounds having a dioxazine ring, such as indole[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenyl-indole[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), and 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), can also be used as the main material.

[0272] <Hole Blocking Layer>

[0273] The hole blocking layer 117 is provided to prevent holes from passing through the second electrode 102 side from the light-emitting layer 113. The hole blocking layer 117 preferably uses a material with high electron transport properties, low hole transport properties and a deep HOMO energy level. Preferably, a material whose HOMO energy level is lower than the HOMO energy level of the material constituting the light-emitting layer (at least the main material) is selected from the substances listed later as materials that can be used as the electron transport layer 114, and preferably a material with a HOMO energy level lower than 0.30ev or more is used to form the hole blocking layer. Note that the hole blocking layer transports electrons and can therefore also be regarded as a part of the electron transport layer 114.

[0274] <Electron Transport Layer>

[0275] The electron transport layer (114, 114a, 114b) is a layer that transports electrons injected from the second electrode 102 and the charge generation layer (106, 106a, 106b) by the electron injection layer (115, 115a, 115b) described later to the light-emitting layer (113, 113a, 113b). In addition, the light-emitting device of one embodiment of the present invention has a stacked structure, so the heat resistance is improved. As the electron transport material used for the electron transport layer (114, 114a, 114b), it is preferred that the electron transport material has a 1×10 -6 cm 2 / Vs or more. In addition, as long as the electron transport property is higher than the hole transport property, substances other than the above can be used. In addition, the electron transport layer (114, 114a, 114b) works even if it is a single layer, but a stacked structure of more than two layers can also be used. Note that since the above-mentioned mixed material is heat-resistant, by performing a photolithography process on the electron transport layer using the mixed material, the influence of the thermal process on the device characteristics can be suppressed.

[0276] <<Electron Transport Materials>>

[0277] As an electron transport material that can be used for the electron transport layer (114, 114a, 114b), an organic compound with high electron transport properties can be used, for example, a heteroaromatic compound can be used. Note that a heteroaromatic compound refers to a cyclic compound containing at least two different elements in the ring. Note that as a ring structure, a three-membered ring, a four-membered ring, a five-membered ring, a six-membered ring, etc. are included, and a five-membered ring or a six-membered ring is particularly preferred. As the element contained in the heteroaromatic compound, in addition to carbon, it is preferably any one or more of nitrogen, oxygen and sulfur. It is particularly preferred to use a heteroaromatic compound containing nitrogen (nitrogen-containing heteroaromatic compound), and it is preferred to use a nitrogen-containing heteroaromatic compound or a π-electron-deficient heteroaromatic compound containing the nitrogen-containing heteroaromatic compound. High electron transport materials (electron transport materials) such as π-electron-deficient heteroaromatic compounds.

[0278] Note that the electron transport material may use a material different from the material used for the light-emitting layer. Not all excitons generated by the recombination of carriers in the light-emitting layer may contribute to luminescence, and sometimes diffuse to the layer in contact with or near the light-emitting layer. In order to avoid this phenomenon, the energy level (lowest singlet excitation level or lowest triplet excitation level) of the material used for the layer in contact with or near the light-emitting layer is preferably higher than that of the material used for the light-emitting layer. Thus, when a material different from the material used for the light-emitting layer is used for the electron transport material, a highly efficient device can be obtained.

[0279] Heteroaromatic compounds are organic compounds having at least one heteroaromatic ring.

[0280] Note that the heteroaromatic ring has any one of a pyridine ring, a diazine ring, a triazine ring, a polyazole ring, an oxazole ring, a thiazole ring, etc. Further, the heteroaromatic ring having a diazine ring includes a heteroaromatic ring having a pyrimidine ring, a pyrazine ring, or a pyridazine ring, etc. Further, the heteroaromatic ring having a polyazole ring includes a heteroaromatic ring having an imidazole ring, a triazole ring, or an oxadiazole ring.

[0281] The heteroaromatic ring includes a condensed heteroaromatic ring having a condensed ring structure. Note that examples of the condensed heteroaromatic ring include 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 furadiazine ring, and a benzimidazole ring.

[0282] Note that, for example, among heteroaromatic compounds containing any one or more of nitrogen, oxygen, sulfur, etc. in addition to carbon, as heteroaromatic compounds having a five-membered ring structure, there can be mentioned 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, heteroaromatic compounds having a benzimidazole ring, and the like.

[0283] For example, among heteroaromatic compounds containing any one or more of nitrogen, oxygen, sulfur, etc. in addition to carbon, as heteroaromatic compounds having a six-membered ring structure, there can be mentioned heteroaromatic compounds having heteroaromatic rings such as pyridine rings, diazine rings (including pyrimidine rings, pyrazine rings, pyridazine rings, etc.), triazine rings, and polyazole rings. Note that heteroaromatic compounds having a bipyridine structure, heteroaromatic compounds having a terpyridine structure, etc. can be mentioned, and they are included in the examples of heteroaromatic compounds connected to a pyridine ring.

[0284] Furthermore, examples of heteroaromatic compounds having a fused ring structure in which a portion of the six-membered ring structure is included include heteroaromatic compounds having fused heteroaromatic rings such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, a furanodiazine ring (including a structure in which a furan ring of a furanodiazine ring is fused with an aromatic ring), and a benzimidazole ring.

[0285] Specific examples of heteroaromatic compounds having the above-mentioned five-membered ring structure (polyazole ring (including imidazole ring, triazole ring, oxadiazole ring), oxazole ring, thiazole ring, benzimidazole ring, etc.) include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), -(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), etc.

[0286] Specific examples of heteroaromatic compounds having the above-mentioned six-membered ring structure (including heteroaromatic rings having pyridine rings, diazine rings, triazine rings, etc.) include 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and the like, which are heteroaromatic compounds containing heteroaromatic rings having pyridine rings; 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl -1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl] ]-4,6-diphenyl-1,3,5-triazine (abbreviated as mTpBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviated as BP-SFTzn), 2,6-bis(4-naphthylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl Heteroaromatic compounds containing a heteroaromatic ring having a triazine ring, such as 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1"-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mDBtBPTzn), and mFBPTzn;4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9 -yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 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]benzofurano[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8BP- 4mDBtPBfpm, 9mDBtBPNfpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviated as 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine heteroaromatic compounds containing heteroaromatic rings having a diazine (pyrimidine) ring, such as 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), and the like. Note that the aromatic compounds containing the above heteroaromatic rings include heteroaromatic compounds having condensed heteroaromatic rings. ;

[0287] In addition, 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-carbazole-9-yl)phenyl]-2-phenyl Heteroaromatic compounds containing heteroaromatic rings having diazine (pyrimidine) rings, such as pyrimidine (abbreviation: 6mBP-4Cz2PPm); heteroaromatic compounds containing heteroaromatic rings having triazine rings, such as 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridinyl)-1,3,5-triazine (abbreviation: 2Py3Tz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), etc.

[0288] Specific examples of heteroaromatic compounds having a fused ring structure in which a part of the heteroaromatic compounds includes the above-mentioned six-membered ring structure (heteroaromatic compounds having a fused ring structure) include bathophenanthroline (abbreviation: Bphen), bathocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: 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'-(diphenylene)bis(4-phenylene)bis(f,h]quinazoline) (abbreviation: 2mDBTPDBq-II), heteroaromatic compounds having a quinoxaline ring, such as 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), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), and 2mpPCBPDBq.

[0289] In addition to the above-mentioned heteroaromatic compounds, the following metal complexes can be used for the electron transport layer (114, 114a, 114b). Examples of the metal complexes include tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq3), Almq3, 8-hydroxyquinoline lithium (abbreviated as Liq), BeBq2, bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq), and metal complexes having a quinoline ring or a benzoquinoline ring, and bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ), and the like.

[0290] In addition, as electron transport materials, 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.

[0291] Furthermore, the electron transport layer (114, 114a, 114b) may be a single layer or a stack of two or more layers containing the above-mentioned substances.

[0292] <Electron Injection Layer>

[0293] The electron injection layer (115, 115a, 115b) is a layer containing a substance with high electron injection property. The electron injection layer (115, 115a, 115b) is a layer used to improve the efficiency of injecting electrons from the second electrode 102. It is preferred to use a material with a small difference (less than 0.50 eV) between the work function value of the material used for the second electrode 102 and the LUMO energy level value of the material used for the electron injection layer (115, 115a, 115b). Therefore, as the electron injection layer 115, lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-hydroxyquinoline lithium (I) (abbreviated as Liq), 2-(2-pyridyl) phenol lithium (abbreviated as LiPP), 2-(2-pyridyl)-3-hydroxypyridinolato lithium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl) phenol lithium (abbreviated as LiPPP), lithium oxide (LiO x), alkali metals such as cesium carbonate, alkaline earth metals or their compounds. In addition, rare earth metals such as erbium fluoride (ErF3) and ytterbium (Yb) or rare earth metal compounds can be used. In addition, compounds having a 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeleton, such as 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(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. Note that the electron injection layer (115, 115a, 115b) may be formed by mixing multiple materials mentioned above or by stacking multiple materials mentioned above. In addition, an electron compound may be used for the electron injection layer (115, 115a, 115b). As an example of the electron compound, a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration may be cited. In addition, the substance constituting the electron transport layer (114, 114a, 114b) as described above may also be used.

[0294] In addition, a mixed material formed by mixing an organic compound with an electron donor (donor) can also be used for the electron injection layer (115, 115a, 115b). This 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 with excellent performance in transporting the generated electrons. Specifically, for example, an electron transport material (metal complex and heteroaromatic compound, etc.) used for the electron transport layer (114, 114a, 114b) as described above can be used. As an electron donor, a substance that exhibits electron donating properties to the organic compound can be used. Specifically, alkali metals, alkaline earth metals and rare earth metals are preferably used, and lithium, cesium, magnesium, calcium, erbium, ytterbium, etc. can be mentioned. In addition, alkali metal oxides and alkaline earth metal oxides are preferably used, and lithium oxide, calcium oxide, barium oxide, etc. can be mentioned. In addition, Lewis bases such as magnesium oxide can also be used. In addition, organic compounds such as tetrathiafulvalene (abbreviated as: TTF) can also be used. Alternatively, multiple of these materials can be used in a stacked manner.

[0295] In addition, a mixed material of an organic compound and a metal may be used for the electron injection layer (115, 115a, 115b). Note that 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 a non-shared electron pair is preferably used.

[0296] Therefore, as an organic compound for the above-mentioned mixed material, a mixed material formed by mixing the above-mentioned heteroaromatic compounds and metals that can be used for the electron transport layer can also be used. The heteroaromatic compound is preferably a heteroaromatic compound having a five-membered ring structure (imidazole ring, triazole ring, oxazole ring, oxadiazole ring, thiazole ring, benzimidazole ring, etc.), a heteroaromatic compound having a six-membered ring structure (pyridine ring, diazine ring (including pyrimidine ring, pyrazine ring, pyridazine ring, etc.), a triazine ring, a bipyridine ring, a terpyridine ring, etc.), a heteroaromatic compound having a condensed ring structure (quinoline ring, benzoxaline ring, quinoxaline ring, dibenzoquinoxaline ring, phenanthroline ring, etc.) having a six-membered ring structure, and the like. Materials with non-shared electron pairs. The specific materials have been described above, so their description is omitted here.

[0297] As the metal used for the mixed material, it is preferred to use transition metals belonging to Group 5, Group 7, Group 9 or Group 11 in the periodic table and materials belonging to Group 13, for example, Ag, Cu, Al or In. In addition, at this time, a single occupied orbital (SOMO) is formed between the organic compound and the transition metal.

[0298] In addition, for example, in the case of amplifying light obtained from the light-emitting layer 113b, it is preferably formed in a manner that the optical distance between the second electrode 102 and the light-emitting layer 113b is less than 1 / 4 of the wavelength λ of the light presented by the light-emitting layer 113b. In this case, the optical distance can be adjusted by changing the thickness of the electron transport layer 114b or the electron injection layer 115b.

[0299] In addition, if Fig.13E By providing the charge generation layer 106 between two EL layers (103a, 103b) as in the light-emitting device shown in the figure, a structure (also referred to as a tandem structure) in which a plurality of EL layers are stacked between a pair of electrodes can be provided.

[0300] <Charge Generation Layer>

[0301] The charge generation layer 106 has the following function: when a voltage is applied between the first electrode 101 (anode) and the second electrode 102 (cathode), electrons are injected into the EL layer 103a and holes are injected into the EL layer 103b. The charge generation layer 106 can have a structure in which an electron acceptor (acceptor) is added to the hole transport material (also called a P-type layer), and can also have a structure in which an electron donor (donor) is added to the electron transport material (also called an electron injection buffer layer). Alternatively, these two structures can be stacked. Furthermore, an electron relay layer can be provided between the P-type layer and the electron injection buffer layer. Note that by using the above-mentioned materials to form the charge generation layer 106, the increase in driving voltage caused by stacking EL layers can be suppressed.

[0302] In the case where the charge generation layer 106 has a structure in which an electron acceptor is added to a hole transport material of an organic compound (P-type layer), the material shown in this embodiment can be used as a hole transport material. In addition, as an electron acceptor, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as: F4-TCNQ), chloranil, etc. can be cited. In addition, oxides of metals belonging to Groups 4 to 8 in the periodic table can be cited. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. can be cited. In addition, the above-mentioned acceptor materials can also be used. In addition, a mixed film in which the materials constituting the P-type layer are mixed can be used, and a single film containing each material can also be stacked.

[0303] In the case where the charge generation layer 106 has a structure (electron injection buffer layer) in which an electron donor is added to the electron transport material, the material shown in this embodiment can be used as the electron transport material. In addition, as an 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 their oxides or carbonates can be used. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (Li2O), cesium carbonate, etc. are preferably used. In addition, compounds of alkali metals such as Liq can also be used. In addition, organic compounds such as tetrathianaphthacene can also be used as electron donors. In addition, organic compounds having 1,3,4,6,7,8-tetrahydro-2H-pyrimido[1,2-a]pyrimidine skeletons such as 2hppSF, 2,7hpp2SF, and hpp2Py can also be used as electron donors. When these organic compounds are used as electron donors, when organic compounds containing heteroaromatic rings having phenanthroline rings such as 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-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) are used as combined electron transport materials, the driving voltage of the light-emitting device can be reduced, so it is preferred.

[0304] In the charge generation layer 106, when an electron relay layer is provided between the P-type layer and the electron injection buffer layer, the electron relay layer contains at least a substance having electron transport properties, and has the function of preventing the interaction between the electron injection buffer layer and the P-type layer and smoothly transferring electrons. The LUMO energy level of the substance having electron transport properties contained in the electron relay layer is preferably located between the LUMO energy level of the acceptor substance in the P-type layer and the LUMO energy level of the substance having electron transport properties contained in the electron transport layer in contact with the charge generation layer 106. The specific value of the LUMO energy level of the substance having electron transport properties in the electron relay layer is preferably above -5.00 eV, more preferably above -5.00 eV and below -3.00 eV. In addition, as the substance having electron transport properties in the electron relay layer, it is preferred to use a phthalocyanine material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0305] In terms of light extraction efficiency, the charge generation layer 106 preferably has a light transmittance to visible light (specifically, the charge generation layer 106 has a visible light transmittance of 40% or more). The charge generation layer 106 can function even if its electrical conductivity is lower than that of the first electrode 101 and the second electrode 102 .

[0306] Although Fig.13E Although a structure in which two EL layers 103 are stacked is shown, a structure in which three or more layers are stacked can be formed by providing a charge generating layer between different EL layers.

[0307] <Cap layer>

[0308] Note that although FIG. 13A to FIG. 13F Although not shown in the figure, a cap layer may be provided on the second electrode 102 of the light emitting device. For example, a material with a high refractive index may be used for the cap layer. By providing the cap layer on the second electrode 102, the extraction efficiency of light emitted from the second electrode 102 may be improved.

[0309] Specific examples of materials that can be used for the cap layer include 5,5'-diphenyl-2,2'-di-5H-[1]benzothieno[3,2-c]carbazole (abbreviated as BisBTc), 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DBT3P-II), and the like.

[0310] <Substrate>

[0311] The light-emitting device shown in this embodiment can be formed on various substrates. Note that there is no particular limitation on the type of substrate. 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 including a stainless steel foil, a tungsten substrate, a substrate including a tungsten foil, a flexible substrate, a laminated film, a paper including a fibrous material, or a substrate film.

[0312] Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, and soda-lime glass. Examples of flexible substrates, laminated films, and base films include plastics represented by 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 vapor-deposited films, and paper.

[0313] In addition, when manufacturing the light-emitting device shown in this embodiment, a vapor phase method such as evaporation, a liquid phase method such as spin coating and inkjet can be used. As an evaporation method, a physical evaporation method (PVD method) or a chemical vapor deposition method (CVD method) such as sputtering, ion plating, ion beam evaporation, molecular beam evaporation, and vacuum evaporation can be used. In particular, a layer having various functions (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115) included in the EL layer of the light-emitting device can be formed by a evaporation method (vacuum evaporation method), a coating method (dip coating, dye coating, rod coating, spin coating, spray coating, etc.), a printing method (inkjet method, screen printing (porcelain printing) method, offset printing (lithography) method, flexographic printing (letterpress printing) method, gravure printing, microcontact printing, etc.) and the like.

[0314] Note that when using the above-mentioned coating method, printing method or other film forming method, high molecular weight compounds (oligomers, dendrimers, polymers, etc.), medium molecular weight compounds (compounds between low molecular weight and high molecular weight: molecular weight of 400 to 4000), inorganic compounds (quantum dot materials, etc.) can be used. Note that as quantum dot materials, colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, core-type quantum dot materials, etc. can be used.

[0315] The materials of each layer (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115) constituting the EL layer 103 of the light-emitting device shown in this embodiment are not limited to the materials shown in this embodiment, and any material that can satisfy the functions of each layer can be used in combination.

[0316] The structure described in this embodiment can be used in combination with the structure described in other embodiment modes as appropriate.

[0317] Implementation 4

[0318] In this embodiment, refer to FIG. 14A to FIG. 15 A display device according to one embodiment of the present invention will be described.

[0319] The display device of this embodiment can be a high-definition display device. Therefore, for example, the display device of this embodiment can be used as a display unit of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, and a display unit of wearable devices that can be worn on the head such as VR devices such as head-mounted displays (HMDs) and glasses-type AR devices.

[0320] In addition, the display device of this embodiment mode may be a high-resolution display device or a large display device. Therefore, for example, the display device of this embodiment mode may be used as a display portion of the following devices: electronic devices with large screens such as television devices, desktop or notebook personal computers, displays for computers, etc., digital signage, large game machines such as pinball machines, etc.; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game machines; portable information terminals; and sound reproduction devices.

[0321] [Display module]

[0322] Fig.14A 2 is a perspective view of a display module 280 . The display module 280 includes a display device 100A and an FPC 290 .

[0323] The display module 280 includes a substrate 291 and a substrate 292. The display module 280 includes a display portion 281. The display portion 281 is an image display region in the display module 280, and light from each pixel provided in a pixel portion 284 described below can be viewed.

[0324] Fig. 14B 2 is a perspective view of a structure on one side of a substrate 291. 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. In addition, a terminal portion 285 for connecting to the FPC 290 is provided on a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 is electrically connected to the circuit portion 282 via a wiring portion 286 composed of a plurality of wirings.

[0325] The pixel portion 284 includes a plurality of pixels 284a arranged periodically. Fig. 14B An enlarged view of one pixel 284a is shown on the right side of FIG. The pixel 284a may adopt various structures described in the above embodiment. Fig. 14BPixel 284a is shown having Figure 1A An example of the same structure of pixel 110 is shown.

[0326] The pixel circuit portion 283 includes a plurality of pixel circuits 283 a arranged periodically.

[0327] One pixel circuit 283a controls the driving of multiple elements included in one pixel 284a. One pixel circuit 283a can be composed of three circuits that control the light emission of one light emitting device. For example, the pixel circuit 283a can adopt a structure having at least one selection transistor, one current control transistor (driving transistor) and a capacitor for one light emitting device. At this time, the gate of the selection transistor is input with a gate signal, and the source is input with a source signal. Thus, an active matrix display device is realized.

[0328] The circuit unit 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit unit 283. For example, it preferably includes one or both of a gate line driving circuit and a source line driving circuit. In addition, it may include at least one of a calculation circuit, a storage circuit, and a power supply circuit.

[0329] The FPC 290 is used as wiring for supplying video signals, power supply potential, and the like from the outside to the circuit portion 282. Alternatively, an IC may be mounted on the FPC 290.

[0330] The display module 280 can adopt a structure in which one or both of the pixel circuit unit 283 and the circuit unit 282 are overlapped on the lower side of the pixel unit 284, so that the display unit 281 can have an extremely high aperture ratio (effective display area ratio). For example, the aperture ratio of the display unit 281 can be 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, thereby making the display unit 281 have an extremely high definition. For example, the display unit 281 preferably has a definition configuration pixel 284a of 2000ppi or more, more preferably 3000ppi or more, more preferably 5000ppi or more, and more preferably 6000ppi or more and 20000ppi or less or 30000ppi or less.

[0331] This high-definition display module 280 is suitable for use in VR devices such as HMD or glasses-type AR devices. For example, because the display module 280 has an extremely high-definition display unit 281, in the structure of viewing the display unit of the display module 280 through a lens, even if the display unit is magnified by a lens, the user cannot see the pixels, thereby achieving a highly immersive display. In addition, without limitation to this, the display module 280 can also be applied to electronic devices with a relatively small display unit. For example, it is suitable for use in the display unit of wearable electronic devices such as watch-type devices.

[0332] [Display device 100B]

[0333] Fig.15 The display device 100B shown 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 .

[0334] Fig. 14B The sub-pixel 50R shown includes a light emitting device 10R, the sub-pixel 50G includes a light emitting device 10G, the sub-pixel 50B includes a light emitting device 10B, and the sub-pixel 50X includes a light emitting device 10X.

[0335] Substrate 301 is equivalent to Fig.14A and Fig. 14B The stacked-layer structure from the substrate 301 to the insulating layer 255c corresponds to the layer 121 including the transistor in the first embodiment.

[0336] The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, for example, a semiconductor substrate such as a single crystal silicon substrate can be used. The transistor 310 includes a portion 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 is used as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311, and is used as a gate insulating layer. The low resistance region 312 is a region doped with impurities in the substrate 301, and is used as one of a source and a drain. The insulating layer 314 covers the side of the conductive layer 311.

[0337] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0338] In addition, an insulating layer 261 is provided to cover the transistor 310 , and the capacitor 240 is provided over the insulating layer 261 .

[0339] Capacitor 240 includes conductive layer 241, conductive layer 245, and insulating layer 243 therebetween. Conductive layer 241 serves as one electrode in capacitor 240, conductive layer 245 serves as the other electrode in capacitor 240, and insulating layer 243 serves as a dielectric of capacitor 240.

[0340] The conductive layer 241 is provided on the insulating layer 261 and 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 through the plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided in a manner covering the conductive layer 241. The conductive layer 245 is provided in a region overlapping the conductive layer 241 via the insulating layer 243.

[0341] In addition, in at least one of the layers of the conductive layer included in the layer 121 having transistors, a conductive layer surrounding the outside of the display portion 281 (or the pixel portion 284) is preferably provided. This conductive layer is also called a guard ring. By providing this conductive layer, it is possible to suppress damage to these elements due to the following reasons: high voltage is applied to elements such as transistors and light-emitting devices due to ESD (electrostatic discharge) or charging in a process using plasma.

[0342] The insulating layer 255a is provided in a manner covering the capacitor 240, the insulating layer 255b is provided on the insulating layer 255a, and the 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.

[0343] The anode of the light-emitting devices 10R, 10G, 10B, and 10X is electrically connected to one of the source and the drain of the transistor 310 through the plug 256 buried in the insulating layer 243, the insulating layer 255a, the insulating layer 255b, and the insulating layer 255c, the conductive layer 241 buried in the insulating layer 254, and the plug 271 buried in the insulating layer 261. The height of the surface of the insulating layer 255c in contact with the anode is the same or substantially the same as the height of the surface of the plug 256 in contact with the anode. Various conductive materials can be used for the plug.

[0344] In addition, a protective layer 122 is provided on the light-emitting devices 10R, 10G, 10B, and 10X. A substrate 124 is bonded to the protective layer 122 via a resin layer 123. The details of the components from the light-emitting device to the substrate 124 can be referred to Embodiment 1. The substrate 124 corresponds to Fig.14A The substrate 292 in FIG.

[0345] As the protective layer 122, at least one of an insulating film, a semiconductor film, and a conductive film can be used. When the protective layer 122 includes an inorganic film, degradation of the light-emitting device can be suppressed, such as preventing oxidation of the cathode, suppressing impurities (water and oxygen, etc.) from entering the light-emitting device, etc., thereby improving the reliability of the display device.

[0346] As the protective layer 122, for example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used. Specific examples of these inorganic insulating films can be found in the description of the insulating layer 125. In particular, the protective layer 122 preferably includes a nitride insulating film or a nitride oxide insulating film, and more preferably includes a nitride insulating film.

[0347] As the resin layer 123, various curing adhesives such as light curing adhesives such as ultraviolet curing adhesives, reaction curing adhesives, heat curing adhesives, anaerobic adhesives, etc. can be used. As these adhesives, epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, EVA (ethylene-vinyl acetate) resins, etc. can be cited. In particular, it is preferred to use materials with low moisture permeability such as epoxy resins. In addition, two-liquid mixed resins can also be used. In addition, adhesive sheets, etc. can also be used.

[0348] The substrate 124 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc. The substrate on the side that extracts light from the light-emitting device uses a material that allows the light to pass through. By using a flexible material for the substrate, the flexibility of the display device can be improved. As the substrate, a polarizing plate or the like can also be used. In this way, various components can be used as the substrate.

[0349] As the substrate 124, the following materials can be used: polyester resins such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resins, acrylic resins, polyimide resins, polymethyl methacrylate resins, polycarbonate (PC) resins, polyether sulfone (PES) resins, polyamide resins (nylon, aramid, etc.), polysiloxane resins, cycloolefin resins, polystyrene resins, polyamide-imide resins, polyurethane resins, polyvinyl chloride resins, polyvinylidene chloride resins, polypropylene resins, polytetrafluoroethylene (PTFE) resins, ABS resins, cellulose nanofibers, etc. As the substrate 124, glass whose thickness is reduced to a degree that it has flexibility can also be used.

[0350] An inorganic insulating film is preferably used as the insulating layer 125. As the inorganic insulating film, for example, a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, an aluminum nitride film, or the like can be used. In addition, 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, a neodymium oxide film, or the like can also be used.

[0351] There is no particular limitation on the structure of the transistor included in the display device of this embodiment. For example, a planar transistor, a staggered transistor, or an inversely staggered transistor may be used. In addition, a top-gate or bottom-gate transistor structure may be used. Alternatively, a gate may be provided above and below the semiconductor layer forming the channel.

[0352] There is no particular restriction on the crystallinity of the semiconductor material used for the transistor, and an amorphous semiconductor, a single crystal semiconductor, or a semiconductor other than a single crystal semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, or a semiconductor having a crystallized region in part thereof) can be used. When a single crystal semiconductor or a semiconductor having crystallinity is used, it is preferred because it can suppress the degradation of the characteristics of the transistor.

[0353] A metal oxide (also referred to as an oxide semiconductor) is preferably used for the semiconductor layer of the transistor. That is, the display device of this embodiment preferably uses a transistor including a metal oxide in a channel formation region (hereinafter referred to as an OS transistor).

[0354] Examples of crystalline oxide semiconductors include CAAC (c-axis-aligned crystalline)-OS and nc (nanocrystalline)-OS.

[0355] Alternatively, a transistor (Si transistor) using silicon for the channel formation region may be used. Examples of silicon include single crystal silicon, polycrystalline silicon, amorphous silicon, and the like. In particular, a transistor containing low temperature polycrystalline silicon (LTPS (Low Temperature Poly Silicon)) in the semiconductor layer may be used (hereinafter also referred to as an LTPS transistor). The LTPS transistor has high field effect mobility and good frequency characteristics.

[0356] By using Si transistors such as LTPS transistors, a circuit that needs to be driven at a high frequency (e.g., a source driver circuit) and a display unit can be formed on the same substrate. Therefore, the external circuit mounted on the display device can be simplified, and component costs and mounting costs can be reduced.

[0357] Compared with transistors using amorphous silicon, the field effect mobility of OS transistors is very high. In addition, the leakage current between the source and the drain in the off state of the OS transistor (hereinafter also referred to as the off-state current) is extremely low, and the charge stored in the capacitor connected in series with the transistor can be maintained for a long period of time. In addition, by using OS transistors, the power consumption of the display device can be reduced.

[0358] In addition, when the light emitting brightness of the light emitting device included in the pixel circuit is increased, the amount of current flowing through the light emitting device needs to be increased. To this end, it is necessary to increase the source-drain voltage of the driving transistor included in the pixel circuit. Because the source-drain withstand voltage of the OS transistor is higher than that of the Si transistor, a high voltage can be applied between the source and drain of the OS transistor. Therefore, by using the OS transistor as the driving transistor included in the pixel circuit, the amount of current flowing through the light emitting device can be increased to improve the light emitting brightness of the light emitting device.

[0359] In addition, when the transistor operates in the saturation region, the OS transistor can make the change in the source-drain current for the change in the gate-source voltage smaller than the Si transistor. Therefore, by using the OS transistor as the driving transistor included in the pixel circuit, the current flowing through the source-drain can be determined in detail according to the change in the gate-source voltage, so the amount of current flowing through the light-emitting device can be controlled. As a result, the number of grayscales of the pixel circuit can be increased.

[0360] In addition, regarding the saturation characteristics of the current flowing when the transistor operates in the saturation region, the OS transistor can make a stable current (saturation current) flow even if the source-drain voltage is gradually increased compared to the Si transistor. Therefore, by using the OS transistor as a driving transistor, even if, for example, the current-voltage characteristics of the light-emitting device are uneven, a stable current can flow through the light-emitting device. That is, when the OS transistor operates in the saturation region, even if the source-drain voltage is increased, the source-drain current remains almost unchanged, so the light-emitting brightness of the light-emitting device can be stabilized.

[0361] As described above, by using an OS transistor as a driving transistor included in a pixel circuit, “suppression of black blur”, “increase in light emission brightness”, “multi-grayscale”, “suppression of unevenness in light emitting devices”, etc. can be achieved.

[0362] For example, the semiconductor layer preferably contains 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.

[0363] In particular, as the semiconductor layer, an oxide containing indium (In), gallium (Ga) and zinc (Zn) (also referred to as IGZO) is preferably used. Alternatively, an oxide containing indium, tin and zinc is preferably used. Alternatively, an oxide containing indium, gallium, tin and zinc is preferably used. Alternatively, an oxide containing indium (In), aluminum (Al) and zinc (Zn) (also referred to as IAZO) is preferably used. Alternatively, an oxide containing indium (In), aluminum (Al), gallium (Ga) and zinc (Zn) (also referred to as IAGZO) is preferably used.

[0364] When an In-M-Zn oxide is used for the semiconductor layer, the atomic ratio of In in the In-M-Zn oxide is preferably greater than the atomic ratio of M. Examples of the atomic ratio of the metal elements in the In-M-Zn oxide include: a composition of In:M:Zn=1:1:1 or in the vicinity thereof, a composition of In:M:Zn=1:1:1.2 or in the vicinity thereof, a composition of In:M:Zn=1:3:2 or in the vicinity thereof, a composition of In:M:Zn=1:3:4 or in the vicinity thereof, a composition of In:M:Zn=2:1:3 or in the vicinity thereof, a composition of In:M:Zn=3:1:2 or in the vicinity thereof, and a composition of In:M:Zn=1:3:4 or in the vicinity thereof. n=4:2:3 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 the nearby compositions include a range of ±30% of the desired atomic ratio.

[0365] For example, when the composition with an atomic ratio of In:Ga:Zn=4:2:3 or thereabouts is described, the following cases are included: when In is 4, Ga is 1 or more and 3 or less, and Zn is 2 or more and 4 or less. In addition, when the composition with an atomic ratio of In:Ga:Zn=5:1:6 or thereabouts is described, the following cases are included: when In is 5, Ga is greater than 0.1 and 2 or less, and Zn is 5 or more and 7 or less. In addition, when the composition with an atomic ratio of In:Ga:Zn=1:1:1 or thereabouts is described, the following cases are included: when In is 1, Ga is greater than 0.1 and 2 or less, and Zn is greater than 0.1 and 2 or less.

[0366] The structure described in this embodiment can be used in combination with the structure described in other embodiment modes as appropriate.

[0367] Implementation method 5

[0368] In this embodiment, using FIG. 16A to FIG. 18GAn electronic device according to one embodiment of the present invention will be described.

[0369] The electronic device of this embodiment includes a 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 achieve high definition and high resolution. Therefore, it can be used in the display portion of various electronic devices.

[0370] Electronic devices include, for example, television sets, desktop or notebook personal computers, displays for computers, etc., digital signage, large-scale game consoles such as pinball machines, and other electronic devices with larger screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, sound reproduction devices, and the like.

[0371] In particular, since the display device of one embodiment of the present invention can improve the clarity, it can be suitably used in electronic devices including a smaller display unit. Examples of such electronic devices include watch-type and bracelet-type information terminal devices (wearable devices), wearable devices that can be worn on the head, VR devices such as head-mounted displays, glasses-type AR devices, and MR devices.

[0372] A display device according to 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), 8K (7680×4320 pixels), etc. In particular, the resolution is preferably set to 4K, 8K or above. In addition, the pixel density (clarity) in the display device according to one embodiment of the present invention is preferably 100 ppi or more, preferably 300 ppi or more, more preferably 500 ppi or more, further preferably 1000 ppi or more, further preferably 2000 ppi or more, further preferably 3000 ppi or more, further preferably 5000 ppi or more, and further preferably 7000 ppi or more. By using a display device having one or both of high resolution and high definition, the sense of reality and depth can be further improved 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 adapt to various screen ratios such as 1:1 (square), 4:3, 16:9, 16:10, etc.

[0373] The electronic device of this embodiment may also include a sensor (the sensor has the function of detecting, detecting or measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared).

[0374] The electronic device of this embodiment may have various functions. For example, it may have the following functions: a function of displaying various information (static images, dynamic images, text images, etc.) on a display unit; a function of a touch panel; a function of displaying a calendar, date, or time, etc.; a function of executing various software (programs); a function of wireless communication; a function of reading programs or data stored in a storage medium; etc.

[0375] use FIG. 16A to FIG. 16D An example of a wearable device that can be worn on the head is described. These wearable devices have at least one of a function of displaying AR content, a function of displaying VR content, a function of displaying SR content, and a function of displaying MR content. When an electronic device has a function of displaying at least one of AR, VR, SR, MR, etc., the user's sense of immersion can be improved.

[0376] Fig.16A The electronic device 700A shown and Fig. 16B The electronic devices 700B shown include a pair of display panels 751, a pair of frames 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 components 753, glasses frames 757 and a pair of nose pads 758.

[0377] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, an electronic device capable of performing extremely high-definition display can be realized.

[0378] Both the electronic device 700A and the electronic device 700B can project the image displayed by the display panel 751 onto the display area 756 in the optical member 753. Since the optical member 753 is light-transmissive, the user can see the image displayed in the display area overlapping the transmitted image seen through the optical member 753. Therefore, both the electronic device 700A and the electronic device 700B are electronic devices capable of AR display.

[0379] The electronic device 700A and the electronic device 700B may also be provided with a camera capable of photographing the front as an imaging unit. In addition, by providing an acceleration sensor such as a gyro sensor on the electronic device 700A and the electronic device 700B, the user's head orientation can be detected and an image corresponding to the direction can be displayed on the display area 756.

[0380] The communication unit includes a wireless communication device, through which a video signal etc. can be supplied. In addition to or in place of the wireless communication device, a connector to which a cable for supplying a video signal and a power supply potential can be connected may be included.

[0381] Furthermore, electronic device 700A and electronic device 700B are provided with batteries, and can be charged wirelessly or by wire, or both.

[0382] The frame 721 may also be provided with a touch sensor module. The touch sensor module has a function of detecting whether the outer surface of the frame 721 is touched. Through the touch sensor module, various processes can be performed by detecting a user's tapping operation or sliding operation. For example, a process such as temporarily stopping or reproducing a dynamic image can be performed through a tapping operation, and a process such as fast forwarding or rewinding can be performed through a sliding operation. In addition, by providing a touch sensor module in each of the two frames 721, the operating range can be expanded.

[0383] As the touch sensor module, various touch sensors can be used. For example, various methods such as electrostatic capacitance, resistance film, infrared, electromagnetic induction, surface acoustic wave, and optical can be used. In particular, it is preferred to use electrostatic capacitance or optical sensors in the touch sensor module.

[0384] When an optical touch sensor is used, a photoelectric conversion device (also referred to as a photoelectric conversion element) can be used as a light receiving device. Inorganic semiconductors and organic semiconductors or both can be used in the active layer of the photoelectric conversion device.

[0385] Fig. 16C The electronic device 800A shown and Fig.16D The electronic devices 800B shown each include a pair of display portions 820 , a housing 821 , a communication portion 822 , a pair of mounting portions 823 , a control portion 824 , a pair of imaging portions 825 , and a pair of lenses 832 .

[0386] The display unit 820 may be a display device according to one embodiment of the present invention. Therefore, an electronic device capable of displaying with extremely high definition may be realized, thereby allowing the user to experience a high sense of immersion.

[0387] The display unit 820 is provided at a position visible through the lens 832 inside the housing 821. In addition, by displaying different images between the pair of display units 820, three-dimensional display using parallax can be performed.

[0388] The electronic device 800A and the electronic device 800B can both be referred to as VR-oriented electronic devices. A user who wears the electronic device 800A or the electronic device 800B can see the image displayed on the display unit 820 through the lens 832 .

[0389] The electronic device 800A and the electronic device 800B preferably have a mechanism in which the left and right positions of the lens 832 and the display unit 820 can be adjusted so that the lens 832 and the display unit 820 are located at the most suitable position according to the position of the user's eyes. In addition, it is preferable to have a mechanism in which the focus is adjusted by changing the distance between the lens 832 and the display unit 820.

[0390] The user can use the mounting portion 823 to mount the electronic device 800A or the electronic device 800B on the head. Fig. 16C In the examples, the mounting portion 823 is shaped like the temples of glasses (also called hinges, temples, etc.), but is not limited to this. As long as the user can wear it, the mounting portion 823 may have a helmet-type or belt-type shape.

[0391] The imaging unit 825 has a function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, a plurality of cameras can be provided to correspond to various viewing angles such as telephoto and wide angle.

[0392] Note that the example including the imaging unit 825 is shown here, and a distance measuring sensor (hereinafter, also referred to as a detection unit) capable of measuring the distance to the object may be provided. In other words, the imaging unit 825 is a form of a detection unit. As the detection unit, for example, an image sensor or a distance image sensor such as a laser radar (LIDAR: Light Detection and Ranging) may be used. By using the image obtained by the camera and the image obtained by the distance image sensor, more information can be obtained, and a more accurate gesture operation can be achieved.

[0393] The electronic device 800A may also include a vibration mechanism used as a bone conduction headset. For example, any one or more of the display unit 820, the frame 821, and the mounting unit 823 may adopt a structure including the vibration mechanism. Thus, there is no need to separately provide audio equipment such as headphones, earphones, or speakers, and the image and sound can be enjoyed by only installing the electronic device 800A.

[0394] Electronic device 800A and electronic device 800B may both include an input terminal (also referred to as an input unit) to which 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 may be connected.

[0395] An electronic device according to one embodiment of the present invention may also have a function of wirelessly communicating with earphone 750. Earphone 750 includes a communication unit (not shown) and has a wireless communication function. Earphone 750 can receive information (such as sound data) from the electronic device through the wireless communication function. For example, Fig.16A The electronic device 700A shown has a function of transmitting information to the headset 750 through a wireless communication function. In addition, for example Fig. 16C The electronic device 800A shown has a function of transmitting information to the headset 750 through a wireless communication function.

[0396] Furthermore, the electronic device may include an earphone unit. Fig. 16B The electronic device 700B shown includes an earphone unit 727. For example, a structure in which the earphone unit 727 and the control unit are connected in a wired manner may be adopted. A part of the wiring connecting the earphone unit 727 and the control unit may also be arranged inside the frame 721 or the mounting portion 723.

[0397] same, Fig.16D The electronic device 800B shown includes an earphone unit 827. For example, a structure in which the earphone unit 827 and the control unit 824 are connected in a wired manner may be adopted. A part of the wiring connecting the earphone unit 827 and the control unit 824 may also be arranged inside the frame 821 or the mounting portion 823. In addition, the earphone unit 827 and the mounting portion 823 may also include magnets. Thus, the earphone unit 827 can be fixed to the mounting portion 823 by magnetic force, and storage becomes easy, which is preferred.

[0398] The electronic device may also include a sound output terminal that can be connected to earphones or headphones. In addition, the electronic device may also include one or both of a sound input terminal and a sound input mechanism. As the sound input mechanism, for example, a sound receiving device such as a microphone may be used. By providing the sound input mechanism to the electronic device, the electronic device can have the so-called earphone function.

[0399] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type (electronic devices 700A and 700B, etc.) and goggles-type (electronic devices 800A and 800B, etc.) are preferable.

[0400] Furthermore, the electronic device according to one embodiment of the present invention can transmit information to the headset in a wired or wireless manner.

[0401] Fig.17A The electronic device 6500 shown is a portable information terminal device that can be used as a smartphone.

[0402] 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, a light source 6508, and the like. The display portion 6502 has a touch panel function.

[0403] As the display portion 6502 , a display device which is one embodiment of the present invention can be used.

[0404] Fig. 17B 6506 is a schematic cross-sectional view of an end portion of a housing 6501 on the microphone 6506 side.

[0405] A light-transmitting protective component 6510 is provided on one side of the display surface of the frame 6501, and a display panel 6511, an optical component 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are provided in the space surrounded by the frame 6501 and the protective component 6510.

[0406] The display panel 6511 , the optical member 6512 , and the touch sensor panel 6513 are fixed to the protective member 6510 using an adhesive layer (not shown).

[0407] In a region outside the display portion 6502, a portion of the display panel 6511 is folded back, and the folded back portion 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.

[0408] The display panel 6511 can use a display device of one embodiment of the present invention. Thus, 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 installed while suppressing the thickness of the electronic device. In addition, by folding a portion of the display panel 6511 to provide a connection portion with the FPC 6515 on the back of the pixel portion, an electronic device with a narrow frame can be realized.

[0409] Fig. 17C 100 shows an example of a television set. In a television set 7100, a display portion 7000 is incorporated in a housing 7101. Here, a structure in which the housing 7101 is supported by a stand 7103 is shown.

[0410] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0411] The operation can be performed by using the operation switch provided in the frame 7101 and the remote control operation machine 7111 provided separately. Fig. 17CIn addition, the display unit 7000 may be provided with a touch sensor, and the television set 7100 may be operated by touching the display unit 7000 with a finger or the like. In addition, the remote control unit 7111 may be provided with a display unit that displays information output from the remote control unit 7111. By using the operation keys or the touch panel provided in the remote control unit 7111, the channel and volume can be operated, and the image displayed on the display unit 7000 can be operated.

[0412] In addition, the television device 7100 includes a receiver and a modem. The receiver can receive general television broadcasts. Furthermore, the modem can be connected to a wired or wireless communication network to perform one-way (from a sender to a receiver) or two-way (between a sender and a receiver or between receivers, etc.) information communication.

[0413] Fig.17D 1 shows an example of a notebook personal computer. The notebook 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 .

[0414] The display device of one embodiment of the present invention can be applied to the display portion 7000 .

[0415] Fig.17E and Fig.17F An example of digital signage is shown.

[0416] Fig.17E The digital signage 7300 shown includes a housing 7301, a display portion 7000, a speaker 7303, etc. In addition, an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, etc. may be included.

[0417] Fig.17F The digital signage 7400 is shown to be disposed on a cylindrical pillar 7401. The digital signage 7400 includes a display unit 7000 disposed along a curved surface of the pillar 7401.

[0418] exist Fig.17E and Fig.17F In the embodiment of the present invention, the display device can be used for the display portion 7000.

[0419] The larger the display unit 7000 is, the more information can be provided at one time. The larger the display unit 7000 is, the easier it is to attract people's attention, for example, the advertising effect can be improved.

[0420] By using a touch panel for the display unit 7000, not only can a static image or a dynamic image be displayed on the display unit 7000, but the user can also intuitively operate it, so it is preferred. In addition, when used for providing information such as route information or traffic information, the ease of use can be improved through intuitive operation.

[0421] like Fig.17E and Fig.17F As shown, the digital signage 7300 or the digital signage 7400 can preferably be linked with the information terminal device 7311 or the information terminal device 7411 such as a smartphone carried by the user through wireless communication. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal device 7311 or the information terminal device 7411. In addition, by operating the information terminal device 7311 or the information terminal device 7411, the display of the display unit 7000 can be switched.

[0422] Furthermore, the game can be executed on the digital signage 7300 or the digital signage 7400 using the screen of the information terminal device 7311 or the information terminal device 7411 as an operation unit (controller). Thus, an unspecified number of users can participate in the game at the same time and enjoy the game.

[0423] FIG. 18A to FIG. 18G The electronic device shown includes a frame 9000, a display portion 9001, a speaker 9003, an operation key 9005 (including a power switch or an operation switch), a connecting terminal 9006, a sensor 9007 (the sensor has the function of detecting, detecting or measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared), a microphone 9008, etc.

[0424] FIG. 18A to FIG. 18G The electronic device shown has various functions. For example, it may have the following functions: a function of displaying various information (static images, dynamic images, text images, etc.) on a display unit; a function of a touch panel; a function of displaying a calendar, date, or time, etc.; a function of controlling processing by using various software (programs); a function of wireless communication; a function of reading out programs or data stored in a storage medium and processing them; etc. Note that the functions of the electronic device are not limited to the above functions, but may have various functions. The electronic device may include multiple display units. In addition, a camera or the like may be provided in the electronic device so that it has the following functions: a function of taking a static image or a dynamic image, and storing the taken image in a storage medium (an external storage medium or a storage medium built into the camera); a function of displaying the taken image on a display unit; etc.

[0425] Below, we explain in detail FIG. 18A to FIG. 18G Electronic equipment shown.

[0426] Fig.18A 9101 is a perspective view showing a portable information terminal 9101. The portable information terminal 9101 can be used as a smart phone, for example. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, and the like can also be provided in the portable information terminal 9101. In addition, as the portable information terminal 9101, text or image information can be displayed on multiple surfaces thereof. Fig.18A 9050. In addition, information 9051 indicated by a dotted rectangle may be displayed on another surface of the display unit 9001. Examples of information 9051 include information indicating that an email, SNS, or phone call has been received; a title of the email or SNS; a sender's name of the email or SNS; a date; a time; a remaining battery level; and radio wave strength. Alternatively, icon 9050 may be displayed at a location where information 9051 is displayed.

[0427] Fig.18B 9102 is a three-dimensional diagram showing a portable information terminal 9102. The portable information terminal 9102 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9102 is placed in a jacket pocket, the user can confirm the information 9053 displayed at a position viewed from above the portable information terminal 9102. For example, the user can confirm the display without taking the portable information terminal 9102 out of the pocket, thereby determining whether to answer a call.

[0428] Fig. 18C 9103. The tablet terminal 9103 can execute various application software such as mobile phone, reading and editing of e-mails and articles, playing music, network communication, computer games, etc. The tablet terminal 9103 includes a display portion 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the frame 9000, an operation key 9005 used as a button for operation on the left side of the frame 9000, and a connection terminal 9006 on the bottom.

[0429] Fig.18D9001 is a stereoscopic diagram showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smart watch (registered trademark). In addition, the display surface of the display unit 9001 is curved, and a display can be performed along its curved display surface. In addition, the portable information terminal 9200 can perform hands-free calls, for example, by communicating with a headset capable of wireless communication. In addition, by using the connection terminal 9006, the portable information terminal 9200 can perform data transmission or charging with other information terminals. Charging can also be performed by wireless power supply.

[0430] FIG. 18E to FIG. 18G 9201 is a perspective view showing a foldable portable information terminal. Fig.18E is a perspective view of the portable information terminal 9201 in an unfolded state. Figure 18G This is a three-dimensional image of the folded state. Fig.18F is from Fig.18E Status and Figure 18G The portable information terminal 9201 is easy to carry in the folded state, and has a large display area that is seamlessly spliced ​​in the unfolded state, so the display is easy to browse. The display unit 9001 included in the portable information terminal 9201 is supported by three frames 9000 connected by hinges 9055. The display unit 9001 can be bent within a range of a curvature radius of 0.1 mm or more and 150 mm or less, for example.

[0431] The structure described in this embodiment can be used in combination with the structure described in other embodiment modes as appropriate.

Claims

1. A display device, comprising: a first light emitting device; a second light emitting device; as well as a third light emitting device, The first light emitting device includes a first anode, a first cathode and a first light emitting layer, and the first light emitting layer is located between the first anode and the first cathode. The second light emitting device comprises a second anode, a second cathode and a second light emitting layer, wherein the second light emitting layer is located between the second anode and the second cathode. The third light emitting device comprises a third anode, a third cathode, a third light emitting layer and a fourth light emitting layer, wherein the third light emitting layer and the fourth light emitting layer are located 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 contacts the third light-emitting layer. The light emitting color of the first light emitting device, the light emitting color of the second light emitting device and the light emitting color of the third light emitting device are different, The first light-emitting layer and the third light-emitting layer include a first light-emitting substance. The second light-emitting layer and the fourth light-emitting layer include a second light-emitting substance, Furthermore, a peak wavelength of an emission spectrum of the first light-emitting substance is different from a peak wavelength of an emission spectrum of the second light-emitting substance.

2. The display device according to claim 1, wherein the peak wavelength of the emission spectrum of the first luminescent substance is longer than the peak wavelength of the emission spectrum of the second luminescent substance, And the thickness of the third light-emitting layer is smaller than the thickness of the fourth light-emitting layer.

3. The display device according to claim 1, wherein the peak wavelength of the emission spectrum of the first luminescent substance is longer than the peak wavelength of the emission spectrum of the second luminescent substance, Furthermore, the first light-emitting layer and the third light-emitting layer include hole transport materials.

4. The display device according to claim 3, The first light-emitting device includes a hole blocking layer located between the first light-emitting layer and the first cathode.

5. The display device according to claim 1, further comprising a fourth light emitting device, The fourth light emitting device comprises a fourth anode, a fourth cathode and a fifth light emitting layer, and the fifth light emitting layer is located between the fourth anode and the fourth cathode. The third light emitting device includes a sixth light emitting layer located 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 contacts the fourth light-emitting layer. The fifth light-emitting layer and the sixth light-emitting layer include a third light-emitting substance, Furthermore, a peak wavelength of an emission spectrum of the third light-emitting substance is different from a peak wavelength of an emission spectrum of the first light-emitting substance and a peak wavelength of an emission spectrum of the second light-emitting substance.

6. A display device, comprising: a first light emitting device; a second light emitting device; as well as a third light emitting device, The first light-emitting device includes a first anode, a first cathode, a first light-emitting layer and a first hole blocking layer, wherein the first light-emitting layer and the first hole blocking layer are located between the first anode and the first cathode. The first hole blocking layer is located between the first light-emitting layer and the first cathode. The second light emitting device comprises a second anode, a second cathode and a second light emitting layer, wherein the second light emitting layer is located between the second anode and the second cathode. The third light emitting device comprises a third anode, a third cathode, a third light emitting layer and a fourth light emitting layer, wherein the third light emitting layer and the fourth light emitting layer are located 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 light emitting color of the first light emitting device, the light emitting color of the second light emitting device and the light emitting color of the third light emitting device are different, The first light-emitting layer and the third light-emitting layer include a first light-emitting substance and a hole transport material. The second light-emitting layer and the fourth light-emitting layer include a second light-emitting substance, Furthermore, a peak wavelength of an emission spectrum of the first light-emitting substance is different from a peak wavelength of an emission spectrum of the second light-emitting substance.

7. The display device according to claim 6, The third light-emitting device includes a second hole blocking layer located between the third light-emitting layer and the fourth light-emitting layer.

8. A display device, comprising: a first light emitting device; a second light emitting device; as well as a third light emitting device, The first light-emitting device includes a first anode, a first cathode, a first light-emitting layer, a second light-emitting layer and a first intermediate layer, wherein the first light-emitting layer, the second light-emitting layer and the first intermediate layer are located 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 comprises a second anode, a second cathode, a third light emitting layer, a fourth light emitting layer and a second intermediate layer, wherein the third light emitting layer, the fourth light emitting layer and the second intermediate layer are located between the second anode and the second cathode, The second intermediate layer is located between the third light-emitting layer and the fourth light-emitting layer, The third light emitting device comprises a third anode, a third cathode, a fifth light emitting layer, a sixth light emitting layer and a third intermediate layer, wherein the fifth light emitting layer, the sixth light emitting layer and the third intermediate layer are located 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 light emitting color of the first light emitting device, the light emitting color of the second light emitting device and the light emitting color of the third light emitting device are different, The first light-emitting layer, the second light-emitting layer and the fifth light-emitting layer include a first light-emitting substance, The third light-emitting layer, the fourth light-emitting layer and the sixth light-emitting layer include a second light-emitting substance, Furthermore, a peak wavelength of an emission spectrum of the first light-emitting substance is different from a peak wavelength of an emission spectrum of the second light-emitting substance.

9. The display device according to claim 8, The first intermediate layer, the second intermediate layer and the third intermediate layer all contain organic compounds and alkali metals or alkaline earth metals.

10. The display device according to claim 8, The first intermediate layer, the second intermediate layer and the third intermediate layer contain the same organic compound and the same alkali metal or alkaline earth metal.

11. The display device according to claim 8, further comprising a fourth light emitting device, The fourth light emitting device comprises a fourth anode, a fourth cathode, a seventh light emitting layer, an eighth light emitting layer and a fourth intermediate layer, wherein the seventh light emitting layer, the eighth light emitting layer and the fourth intermediate layer are located 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 includes a ninth light emitting layer located 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 include a third light-emitting substance, Furthermore, a peak wavelength of an emission spectrum of the third light-emitting substance is different from a peak wavelength of an emission spectrum of the first light-emitting substance and a peak wavelength of an emission spectrum of the second light-emitting substance.

12. The display device according to claim 11, The first intermediate layer, the second intermediate layer, the third intermediate layer and the fourth intermediate layer all contain organic compounds and alkali metals or alkaline earth metals.

13. The display device according to claim 11, The first intermediate layer, the second intermediate layer, the third intermediate layer and the fourth intermediate layer contain the same organic compound and the same alkali metal or alkaline earth metal.

Images