Light-emitting device

Abstract

To provide a light-emitting device, an electronic device, and a display device with low power consumption.SOLUTION: A light-emitting device includes a first light-emitting element, a second light-emitting element, and a third light-emitting element, and the first light-emitting element, the second light-emitting element, and the third light-emitting element have a common EL layer, and the EL layer includes a layer including a light-emitting material exhibiting blue fluorescence and a layer including a light-emitting material exhibiting yellow or green phosphorescence, and light emitted from the second light-emitting element is made incident on a color filter layer or a second color conversion layer, and light emitted from the third light-emitting element is made incident on a first color conversion layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention is a light-emitting device, a display device, a display module, a lighting module, The present invention relates to an electronic device and a lighting device. The technical field of one embodiment of the invention disclosed in this specification relates to an object, a method, or a manufacturing method. Alternatively, one aspect of the present invention is a process, machine, manufacture, or or composition of matter. Specifically, the technical field of one embodiment of the present invention disclosed in this specification includes semiconductor devices, display devices, Liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, storage devices, and driving methods thereof, or The manufacturing method thereof can be mentioned as an example. [Background technology]

[0002] With potential such as thinness and light weight, fast response to input signals, and low power consumption, Light-emitting devices (organic electroluminescence (EL) devices) that use organic compounds as light-emitting materials are being used in lighting and display devices of the next generation. Display devices using this technology have been developed and commercialized.

[0003] In an organic EL element, a light-emitting layer is sandwiched between electrodes, and when a voltage is applied, light is injected from the electrodes. The electrons and holes recombine to excite the organic light-emitting material, and the excited state is When the state returns to the ground state, light is emitted. The spectrum of light emitted by a luminescent material is characteristic of that luminescent material. By using different types of organic compounds as luminescent materials, various It is possible to obtain a light-emitting element that emits light of various colors.

[0004] In the case of display devices designed to display images, such as monitors, full-color To reproduce an image, it is necessary to obtain at least three colors of light: red, green, and blue. In addition, in order to improve color reproduction and image quality, the microcavity structure and the Color filters are also used to improve the color purity of the emitted light.

[0005] In order to reduce power consumption, the molecular structure of the light-emitting material used can be changed. Various measures are being taken, such as controlling materials, their compositions, and structures. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2009-129586 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of one embodiment of the present invention is to provide a novel light-emitting device. An object of one embodiment of the present invention is to provide a light-emitting device with low power consumption. In another aspect, an object of the present invention is to provide an electronic device and a display device each having low power consumption. do.

[0008] It is sufficient for one embodiment of the present invention to achieve any one of the above objects. [Means for solving the problem]

[0009] In one embodiment of the present invention, in a light-emitting device using an organic compound as a light-emitting material, The object can be achieved by obtaining the desired emission color using

[0010] One embodiment of the present invention is a light-emitting device having a light-emitting element using an organic compound, The device includes at least a first light emitting element, a second light emitting element, and a third light emitting element. the first light-emitting element, the second light-emitting element, and the third light-emitting element have a common EL layer; The EL layer is a layer containing a light-emitting material that exhibits blue fluorescence and a layer containing a light-emitting material that exhibits green phosphorescence. a layer including a material, and light emitted from the third light-emitting element is incident on the first color conversion layer. The light emitting device is characterized by the above.

[0011] Another embodiment of the present invention is a light emitting device having the above structure, wherein the light emitted from the first light emitting element is A light emitting device that emits blue light through a color filter that transmits blue light. It is a device.

[0012] Another embodiment of the present invention is a light emitting element having the above structure, wherein the light emitted from the second light emitting element is A light emitting device that emits green light through a color filter that transmits the green light. It is an optical device.

[0013] Alternatively, in the above-described structure, light emitted from the second light-emitting element is This is a light emitting device in which light enters a second color conversion layer that emits green light.

[0014] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the first light-emitting element, the second light-emitting element, the third light-emitting element, The optical element is a light emitting device characterized in that it is a tandem type light emitting element.

[0015] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the first light-emitting element, the second light-emitting element, the third light-emitting element, The optical element includes a layer including a light-emitting material that exhibits blue fluorescence and a layer including a light-emitting material that exhibits green phosphorescence. The light-emitting device is characterized in that layers containing the above are formed in close proximity to each other.

[0016] Alternatively, in the above-described structure, one aspect of the present invention is a liquid crystal display device comprising: The light emitting device has a PL quantum yield of greater than 40% in one or both of the layers.

[0017] Alternatively, in the above-described structure, one aspect of the present invention is a liquid crystal display device comprising: The light emitting device has a PL quantum yield of greater than 53.3% in one or both of the layers.

[0018] Alternatively, in the above-described structure, one aspect of the present invention is a liquid crystal display device comprising: A light emitting device in which the PL quantum yield of one or both of the layers is greater than 66%.

[0019] Another embodiment of the present invention is a light-emitting device including a light-emitting element using an organic compound, The light emitting device includes at least a first light emitting element, a second light emitting element, and a third light emitting element. the first light-emitting element has an EL layer of a first configuration, and the second light-emitting element and the third light-emitting element The light-emitting element has an EL layer of a second configuration, and the EL layer of the first configuration exhibits blue fluorescence. a layer containing a light-emitting material that exhibits green phosphorescence and a layer containing a light-emitting material that exhibits green phosphorescence, The EL layer of the second configuration has a layer containing a light-emitting material that exhibits green phosphorescence, and The EL layer of the first configuration and the EL layer of the second configuration have a light-emitting material exhibiting green phosphorescence. The layers included in the third light emitting element are the same layer, and the light emitted by the third light emitting element is incident on the first color conversion layer. The light emitting device is characterized by the above.

[0020] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the green phosphorescent light-emitting material is located closer to the anode than the layer containing the green phosphorescent light-emitting material, A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting green phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a higher electron transporting property than a hole transporting property. It is.

[0021] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the green phosphorescent light-emitting material is located closer to the cathode than the layer containing the green phosphorescent light-emitting material, and A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting green phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a hole transporting property higher than an electron transporting property. It is.

[0022] Another embodiment of the present invention is a light-emitting device including a light-emitting element using an organic compound, The light emitting device includes at least a first light emitting element, a second light emitting element, and a third light emitting element. the first light-emitting element has an EL layer having a third configuration, and the second light-emitting element and the third light-emitting element The light-emitting element has an EL layer of a fourth configuration, and the EL layer of the fourth configuration exhibits blue fluorescence. a layer containing a light-emitting material that exhibits green phosphorescence and a layer containing a light-emitting material that exhibits green phosphorescence, The EL layer of the third configuration has a layer containing a light-emitting material that exhibits blue fluorescence, and the EL layer of the fourth configuration has a layer containing a light-emitting material that exhibits blue fluorescence. The EL layer of the third configuration and the EL layer of the third configuration have a light-emitting material exhibiting blue fluorescence. The light emitted from the third light emitting element is incident on the first color conversion layer. The light emitting device is characterized by the above.

[0023] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the green phosphorescent light-emitting material is located closer to the anode than the layer containing the green phosphorescent light-emitting material, A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting green phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a hole transporting property higher than an electron transporting property. It is.

[0024] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the green phosphorescent light-emitting material is located closer to the cathode than the layer containing the green phosphorescent light-emitting material, and A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting green phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a higher electron transporting property than a hole transporting property. It is.

[0025] Alternatively, in the above-mentioned configuration, one aspect of the present invention is that the PL quantum efficiency of the first color conversion layer is It is a light-emitting device that is 50% more efficient.

[0026] Alternatively, in the above structure, one embodiment of the present invention is The layer includes a first organic compound, a second organic compound, and a light-emitting compound that exhibits green phosphorescence. and a material, the first organic compound and the second organic compound being exciplex forming emitters. It is an optical device.

[0027] Alternatively, in the above-described structure, one embodiment of the present invention is a compound having an emission spectrum of This light-emitting device overlaps with the absorption band on the longest wavelength side of the light-emitting material that exhibits green phosphorescence.

[0028] Another embodiment of the present invention is a light-emitting device including a light-emitting element using an organic compound, The light emitting device includes at least a first light emitting element, a second light emitting element, and a third light emitting element. The first light emitting element, the second light emitting element, and the third light emitting element have a common EL layer. The EL layer contains a light-emitting material that exhibits blue fluorescence and a light-emitting material that exhibits yellow phosphorescence. The light emitted by the second light emitting element is incident on a second color conversion layer, and the light emitted by the third light emitting element is incident on a second color conversion layer. The light emitted by the light emitting device is incident on the first color conversion layer.

[0029] Another embodiment of the present invention is a light emitting device having the above structure, wherein the light emitted from the first light emitting element is A light emitting device that emits blue light through a color filter that transmits blue light. It is a device.

[0030] Alternatively, in the above structure, one embodiment of the present invention is a light-emitting element that increases blue light. A light emitting device having a wide microcavity structure.

[0031] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the first light-emitting element, the second light-emitting element, the third light-emitting element, The optical element is a light emitting device characterized in that it is a tandem type light emitting element.

[0032] Another embodiment of the present invention is a semiconductor device having the above structure, wherein the first light-emitting element, the second light-emitting element, the third light-emitting element, The optical element includes a layer containing a light-emitting material that exhibits blue fluorescence and a layer containing a light-emitting material that exhibits yellow phosphorescence. The light-emitting device is characterized in that layers containing the above are formed in close proximity to each other.

[0033] Alternatively, in the above-mentioned configuration, one aspect of the present invention is that the PL quantum efficiency of the first color conversion layer is It is a light-emitting device that is 40% larger.

[0034] Alternatively, in the above-mentioned configuration, one aspect of the present invention is that the PL quantum efficiency of the first color conversion layer is It is a light-emitting device that is 50% larger.

[0035] Alternatively, in the above-mentioned configuration, one aspect of the present invention is that the PL quantum efficiency of the first color conversion layer is It is a light-emitting device that is 53.3% larger.

[0036] Alternatively, in the above-mentioned configuration, one aspect of the present invention is that the PL quantum efficiency of the first color conversion layer is It is a light-emitting device that is 66% larger.

[0037] One embodiment of the present invention is a light-emitting device having a light-emitting element using an organic compound, The device includes at least a first light emitting element, a second light emitting element, and a third light emitting element. The first light-emitting element and the second light-emitting element have an EL layer having a fifth configuration, and the third light-emitting element The EL layer of the fifth configuration has a light-emitting material that exhibits blue fluorescence. and a layer containing a light-emitting material that exhibits yellow phosphorescence, The EL layer has a layer containing a light-emitting material that exhibits yellow phosphorescence, and the EL layer of the fifth configuration The layer containing the yellow phosphorescent light-emitting material of the EL layer of the sixth configuration is the same as the layer containing the yellow phosphorescent light-emitting material of the sixth configuration. The light emitted by the second light emitting element is incident on the second color conversion layer, and the light emitted by the third light emitting element is incident on the second color conversion layer. The light emitting device is characterized in that light emitted from the light emitting element is incident on the first color conversion layer.

[0038] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the yellow phosphorescent light-emitting material is located closer to the anode than the layer containing the yellow phosphorescent light-emitting material, A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting yellow phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a higher electron transporting property than a hole transporting property. It is.

[0039] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the yellow phosphorescent light-emitting material is located closer to the cathode than the layer containing the yellow phosphorescent light-emitting material, and A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting yellow phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a hole transporting property higher than an electron transporting property. It is.

[0040] Another embodiment of the present invention is a light-emitting device having the above structure, further comprising a fourth light-emitting element. The light emitted by the fourth light emitting element is emitted through a color filter that transmits yellow light. It is a light emitting device that emits light.

[0041] Another embodiment of the present invention is a light-emitting device including a light-emitting element using an organic compound, The light emitting device includes at least a first light emitting element, a second light emitting element, and a third light emitting element. the first light-emitting element and the second light-emitting element have an EL layer of a seventh configuration, The light-emitting element has an EL layer of an eighth configuration, and the EL layer of the eighth configuration emits blue fluorescence. A layer including a light-emitting material and a layer including a light-emitting material that exhibits yellow phosphorescence, The EL layer of the seventh configuration has a layer containing a light-emitting material that exhibits blue fluorescence, The EL layer of the eighth configuration and the EL layer of the eighth configuration include the light-emitting material exhibiting blue fluorescence. The light emitted from the second light emitting element is incident on the second color conversion layer, and the light emitted from the second light emitting element is incident on the second color conversion layer. The light emitted by the light emitting element 3 is a light emitting device that enters the first color conversion layer.

[0042] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the yellow phosphorescent light-emitting material is located closer to the anode than the layer containing the yellow phosphorescent light-emitting material, A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting yellow phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a hole transporting property higher than an electron transporting property. It is.

[0043] Alternatively, one embodiment of the present invention is a liquid crystal display device having the above structure, further comprising: The layer containing the yellow phosphorescent light-emitting material is located closer to the cathode than the layer containing the yellow phosphorescent light-emitting material, and A layer including the light-emitting material exhibiting blue fluorescence and a layer including the light-emitting material exhibiting yellow phosphorescence. a light-emitting device, characterized in that the layers contained in the light-emitting device have a higher electron transporting property than a hole transporting property. It is.

[0044] Alternatively, in the above-described configuration, the light-emitting device according to one embodiment of the present invention further comprises a fourth configuration E A fourth light-emitting element having an L layer is provided, and the light emitted by the fourth light-emitting element transmits yellow light. The light is emitted from the light emitting device through a color filter.

[0045] Alternatively, in the above-mentioned configuration, one aspect of the present invention is that the PL quantum efficiency of the first color conversion layer is The light-emitting device has a light-emitting efficiency of 50% or more.

[0046] Alternatively, in the above-described structure, the light emitted from the second color conversion layer is The light emitting device is characterized by emitting colored light.

[0047] Another embodiment of the present invention is a light-emitting material that exhibits yellow phosphorescence in the above structure. The layer includes a first organic compound, a second organic compound, and a light-emitting compound that exhibits yellow phosphorescence. and a material, the first organic compound and the second organic compound being exciplex forming emitters. It is an optical device.

[0048] Alternatively, in the above-described structure, one embodiment of the present invention is a compound having an emission spectrum of This light-emitting device overlaps with the absorption band on the longest wavelength side of the light-emitting material that exhibits yellow phosphorescence.

[0049] Alternatively, in the above-described structure, the light emitted from the first color conversion layer is red. The light emitting device is characterized by emitting light of

[0050] Another embodiment of the present invention is a light-emitting device having the above structure, further comprising a fourth light-emitting element. The light emitted by the fourth light emitting element is incident on a third color conversion layer, and the third color conversion layer The light emitted by the light emitting device is yellow light.

[0051] Alternatively, in the above-mentioned configuration, the first color conversion layer may be formed using quantum dots. The light-emitting device has a color conversion layer.

[0052] Another embodiment of the present invention is a light-emitting device having the above structure, and a sensor, an operation button, a speaker, or the like. It is an electronic device having a camera or a microphone. Effect of the Invention

[0053] According to one embodiment of the present invention, a novel light-emitting device can be provided. In this embodiment, a light emitting device with low power consumption can be provided. With this, it is possible to provide a display device and an electronic device with low power consumption.

[0054] It is sufficient for one embodiment of the present invention to achieve any one of the above objects. [Brief description of the drawings]

[0055] [Figure 1] 1 is a conceptual diagram of a light-emitting device. [Diagram 2]1 is a conceptual diagram of a light-emitting device. [Diagram 3] 1 is a conceptual diagram of a light-emitting device. [Figure 4] 1 is a conceptual diagram of a light-emitting device. [Diagram 5] 1 is a conceptual diagram of a light-emitting element. [Figure 6] FIG. 1 is a conceptual diagram of an active matrix light-emitting device. [Figure 7] FIG. 1 is a conceptual diagram of an active matrix light-emitting device. [Figure 8] FIG. 1 is a conceptual diagram of an active matrix light-emitting device. [Figure 9] FIG. 1 is a conceptual diagram of a passive matrix light-emitting device. [Figure 10] A diagram showing an electronic device. [Figure 11] 1 is a diagram illustrating an in-vehicle display device and a lighting device. [Figure 12] A diagram showing an electronic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0056] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the embodiments and details thereof are not limited to those described above without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that the above may be modified in various ways. The present invention should not be construed as being limited to the description of the embodiments. 1(A) to (D), 2(A) to (D), 3(A) to (D) and 4(A). 1 through 3.

[0057] <Conversion from a tandem element using blue fluorescence and green phosphorescence> FIG. 1(A) shows the light emission of one embodiment of the present invention using a tandem element utilizing blue fluorescence and green phosphorescence. The light emitting device has at least a first light emitting element and a second light emitting element on a substrate 100. The first light-emitting element, the second light-emitting element, and the third light-emitting element are provided. The first emitting device has the EL layer 103 and the second electrode 104 in common, but has a different first electrode. The optical element is connected to the first electrode 102B, the second light emitting element is connected to the first electrode 102G, and the third light emitting element is connected to the first electrode 102C. Each of the electrodes has a first electrode 102R. The color filter 105, the color filter 107B, the color filter 107G, and the color conversion layer 106R The color filter 107B is a color filter that transmits blue light. The color filter 107G is a color filter that transmits green light. 106R contains a color conversion material that emits red light.

[0058] In FIG. 1A, the EL layer 103 is a tandem type EL layer, typically ... The tandem structure is an EL layer having a first light-emitting unit 103b and a second light-emitting unit 103c. The light-emitting unit 103c is laminated with the light-emitting unit 103b via the intermediate layer 109, which is a charge generating layer. Each light-emitting unit has a first electrode 102 as an anode and a second electrode 104 as a cathode. The hole injection layer 114 and the hole transport layer 115 are formed in this order from the first electrode 102 (here, the anode) side. A typical structure includes a light-emitting layer 116, an electron transport layer 117, an electron injection layer 118, etc. In such a structure, the light-emitting material may be contained in the light-emitting layer 116. When the electrode 102 is used as a cathode and the second electrode 104 is used as an anode, the stacking order of the EL layers can be reversed. Note that the EL layer 103 is common to the first to third light-emitting elements.

[0059] Either the first light-emitting unit 103b or the second light-emitting unit 103c is blue. The EL layer 103 emits blue light and the other emits green light. The light obtained is a combination of green fluorescence and green phosphorescence. The organic electroluminescent device has a first organic compound as a host material in addition to the light-emitting material. The first organic compound and the second organic compound form an exciplex, and the exciplex is It is preferable that energy transfer occurs from the exciplex to the light-emitting material. When the emission spectrum overlaps with the absorption band at the longest wavelength of the luminescent material, energy transfer is efficient. This is a preferred configuration since it allows for movement.

[0060] The light emitted from the first light emitting element is emitted outside the light emitting device through the color filter 107B. The light emitted from the second light emitting element is emitted outside the light emitting device through a color filter 107G. The light emitted from the third light emitting element is incident on color conversion layer 106R, and is then emitted from color conversion layer 106 R is excited by the incident light and emits red light.

[0061] Here, each pixel (light emitting element) in the light emitting device having the above configuration is provided with a color filter or a color In this specification, a pixel is defined as a combination of elements related to extraction efficiency, such as a conversion layer and a substrate.) and the external quantum efficiency of each pixel in a light-emitting device having a different configuration from the above configuration. In addition, the carrier balance and excitation efficiency of the light-emitting element used in each light-emitting device are also considered. The probability of generating the initiators is assumed to be the same.

[0062] First, the external quantum efficiency of each pixel in a light-emitting device having a different configuration from the above Calculations are performed. In order to efficiently obtain the three colors of red, green, and blue in a light-emitting device that normally uses tandem elements, For this purpose, it is effective to use luminescent materials that exhibit the respective luminescent wavelengths, and this is practical, efficient, and Considering the balance between these two, blue fluorescent materials, red phosphorescent materials, and green phosphorescent materials are often used. The two-stage tandem structure has two light-emitting units similar to those in FIG. 5(A), and one of the light-emitting units The light-emitting layer of one light-emitting unit is a fluorescent light-emitting layer using a blue fluorescent material, and the light-emitting layer of the other light-emitting unit is a red The phosphorescent layer is made of a green phosphorescent material and a red phosphorescent material.

[0063] In a light-emitting device having such a structure, the internal quantum efficiency of each light-emitting layer is Assuming that the emissive layer is 25% and the phosphorescent emissive layer is 100%, the external quantum efficiency of the blue pixel is 25 ×χ CF (However, CF is the light extraction efficiency when a color filter is used, and χ CF = Maximum transmittance of the color filter used × χ A In addition, χ A is light extraction This is the efficiency excluding the transmittance of the color filter or the PL quantum efficiency of the color conversion layer. The external quantum efficiency of the green and red pixels is 50×χ each CF % (To share the excitons between green and red. For simplicity, we will share them in half. Let us suppose that.)

[0064] Next, considering the light-emitting device having the configuration of FIG. 1(A), the external quantum efficiency of the blue pixel is is 25×χ CF %, and the external quantum efficiency of the green pixel is 100×χ CF % (Phosphorescent layer is green single layer If no color filter is installed, the A %) and the external quantum efficiency of the red pixel is 125 ×χ CC % (where χ CC is the light extraction efficiency when a color conversion layer is used, and χ CC =Use PL quantum yield of the color conversion layer × χ A In addition, 125×χ CC % is This is because it is obtained by color conversion of green phosphorescence with an internal quantum efficiency of 100% and blue fluorescence with an internal quantum efficiency of 25%.) It becomes.

[0065] Here, when comparing the external quantum efficiency of the green pixel with that of the conventional configuration, The configuration is 50×χ CF %, whereas in this configuration it is 100×χ CF %, twice as effective In addition, the external quantum efficiency of the red pixel in the conventional configuration and the configuration in question is compared. In the conventional configuration, CF %, whereas in this configuration it is 125×χ CC %and If the transmittance of the color filter and the PL quantum yield of the color conversion layer are the same, the This suggests that the PL quantum yield of the color conversion layer is approximately equal to the transmittance of the color filter. If the external quantum efficiency is 40% or more, the red pixel will have a better external quantum efficiency than the conventional red pixel. This makes it possible to provide a light emitting device with low power consumption. The color filter 107G can be replaced with a color conversion layer 106G. The raw external quantum efficiency is 125×χ, the same as the red pixel. CC %, and the PL quantum efficiency χ of the color conversion layer CC is the transmittance of the color filter, χ CF If it is more than 40% of the original green pixel, it is better than the conventional green pixel. It is possible to create a green pixel with high external quantum efficiency, enabling a light-emitting device with low power consumption. It becomes.

[0066] As shown in FIG. 2A, a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1A. The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. The EL layer includes a first light-emitting unit 103b and a second light-emitting unit 103c. Furthermore, the light emitted from the fourth light emitting element is incident on the color conversion layer 106Y, which emits yellow light. The external quantum efficiency of this yellow pixel is 100% compared to blue fluorescence with an internal quantum efficiency of 25%. % green phosphorescence is converted into color, so 125×χ CC The result is %.

[0067] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0068] <Conversion from a single element using blue fluorescence and green phosphorescence> FIG. 1B shows the light emission of one embodiment of the present invention using a single element that utilizes blue fluorescence and green phosphorescence. The light-emitting device has at least one The display device includes a first light emitting element, a second light emitting element, a third light emitting element, a substrate 100, a sealing substrate 101, a third light emitting element, and a First electrodes 102B, 102G, 102R, second electrode 104, black matrix 105 1, the color conversion layer 106R, the color filter 107G, and the color filter 107B are also Since this is the same as the light emitting device shown in (A), the explanation will be omitted.

[0069] In FIG. 1B, the EL layer 103d is a single layer, as typified by the structure shown in FIG. In the light-emitting unit, two light-emitting layers (a first light-emitting layer 116d-1 and a second light-emitting layer 116d The first light-emitting layer 116d has a single structure in which the first light-emitting layer 116d is adjacent to the first light-emitting layer 116d. The first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 may be formed in contact with each other, or may be formed with a thickness of more than 0 nm between them. Alternatively, a separation layer having a thickness of 20 nm or less may be provided. The separation layer has a thickness of 1 nm or more and 10 nm or less. It is preferable that the EL layer 103d is a They have something in common.

[0070] In this configuration, the first light-emitting layer 116d-1 and the second light-emitting layer 116d- 2 is one of which emits blue fluorescence and the other emits green phosphorescence. The EL layer 103d emits light that is a combination of blue fluorescence and green phosphorescence. The first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 contain a second light-emitting material as a host material in addition to the light-emitting material. The present invention further comprises a second organic compound, and the first organic compound and The second organic compound forms an exciplex, and energy is transferred from the exciplex to the light-emitting material. In addition, the emission spectrum of the exciplex and the longest wavelength region of the luminescent material are preferably Overlapping absorption bands are more favorable because they allow for efficient energy transfer. .

[0071] The light emitted from the first light emitting element is emitted outside the light emitting device through a blue color filter 107B. The light emitted from the second light emitting element is reflected by a green color filter 107G. The light emitted from the third light emitting element is incident on the color conversion layer 106R and is converted into a color The conversion layer 106R is excited by the incident light and emits red light.

[0072] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and The external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0073] First, the external quantum efficiency of each pixel in a light-emitting device having a different configuration from the above A single structure in which two light-emitting layers are placed close to each other in one light-emitting unit. In a light-emitting device using a light-emitting element having an EL layer, three colors of red, green, and blue can be emitted without using a color conversion layer. To obtain each color, a luminescent material that emits light with an intensity at a wavelength corresponding to that color is required. In order to balance practicality and efficiency, blue fluorescent materials, red phosphorescent materials, and green phosphorescent materials are If a phosphorescent material is used, the first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 may be It is preferable to use a blue fluorescent material in one of the layers and a red phosphorescent material and a green phosphorescent material in the other layer. It is preferable that the internal quantum efficiency of the light-emitting device is 25% for the fluorescent light-emitting layer and 10% for the phosphorescent light-emitting layer. 0%, and assuming that the distribution of excitons is equal among blue, green, and red, the external quantum Efficiency is 8.3×χ CF %, and the external quantum efficiency of the green and red pixels is 33.3×χ CF %and become.

[0074] Next, consider a light-emitting device having the configuration shown in FIG. 1(B). In addition to the same assumptions, Assuming that the distribution of electrons is equal between blue and green, the external quantum efficiency of the blue pixel is 12.5 × χ C F %, and the external quantum efficiency of the green pixel is 50×χ CF %, and the external quantum efficiency of the red pixel is 62.5× χ CC %. In this way, by using the configuration of one embodiment of the present invention, It is possible to obtain a light-emitting element having a very high efficiency compared to the above. The color filter 107G that transmits light can be replaced with a color conversion layer 106G. In this case, the external quantum efficiency of the green pixel is the same as that of the red pixel, 62.5×χ CC The result is %.

[0075] Here, we compare the external quantum efficiency of each pixel between the conventional configuration and this configuration. The conventional configuration is 8.3×χ CF %, while this configuration is 12.5×χ CF %, approximately The efficiency is expected to be improved by 1.5 times. In addition, the conventional configuration of the green pixel is 33×χ CF % In contrast, this configuration is 50×χ CF %, and the efficiency of green pixels is expected to improve by about 1.5 times. For red pixels, the conventional configuration is 33×χ CF %, while this configuration is 62.5×χ C C %, and if the transmittance of the color filter and the PL quantum yield of the color conversion layer are the same, the This means that the PL quantum yield of the color conversion layer is approximately 1.88 times higher than that of the color filter. If the transmittance of the photodiode is 53.3% or more, it will be a red pixel with better external quantum efficiency than the conventional red pixel. Therefore, a light emitting device with low power consumption can be provided.

[0076] In addition, as shown in FIG. 2B, a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1B. The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. Two light-emitting layers (a first light-emitting layer 116d-1 and a second light-emitting layer 116d-2) are provided adjacent to each other. The EL layer has a single structure in which the fourth light-emitting element is color-converted. The light enters the color conversion layer 106Y, which emits yellow light. The efficiency is 62.5×χ because it is obtained by color conversion of blue fluorescence and green phosphorescence. CC The result is %.

[0077] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0078] <Conversion from blue fluorescent single element and green phosphorescent single element (one-time coating) 1> FIG. 1C shows an embodiment of the present invention using a single blue fluorescent element and a single green phosphorescent element. The light-emitting device shown in FIG. Each of the light emitting devices has a first light emitting element to a third light emitting element, and a substrate 100 and a sealing substrate 10 1, first electrodes 102B, 102G, 102R, second electrode 104, black matrix The color conversion layer 105 and the color conversion layer 106R are similar to those in the light emitting device shown in FIG. is omitted.

[0079] In the light-emitting device shown in FIG. 1C, the first light-emitting element has an EL layer of a first configuration, The second light-emitting element and the third light-emitting element have an EL layer of the second configuration.

[0080] The EL layers of the first configuration are a first EL layer 103e, a second EL layer 103f, a third EL layer 103c, and a The EL layer of the second configuration is a laminate of a first EL layer 103g and a fourth EL layer 103h. A structure in which a first EL layer 103e, a third EL layer 103g, and a fourth EL layer 103h are laminated It is a completion.

[0081] When the first electrode is an anode and the second electrode is a cathode, the first EL layer 103e is These layers correspond to the hole injection layer 114 and the hole transport layer 115 in (B). The EL layer 103f corresponds to the first light-emitting layer 116d-1 in FIG. The third EL layer 103g corresponds to the second light-emitting layer 116d-2 in FIG. The fourth EL layer 103h corresponds to the electron transport layer 117 and the electron injection layer 118 in FIG. 5(B). That is, the EL layer of the first configuration corresponds to the EL layer 103d in FIG. The EL layer of the second configuration has a structure similar to that of the EL layer 103a in FIG. 5(C). It becomes.

[0082] The EL layer of the first configuration and the EL layer of the second configuration can be formed by a single coating process. By simply applying the paint once, a single layer of a fluorescent light-emitting layer and a phosphorescent light-emitting layer can be produced. As compared with a light emitting device having a conventional structure, light emission can be achieved with a very high efficiency.

[0083] The second EL layer 103f contains an organic compound that emits blue fluorescence as a light-emitting material. The third EL layer 103g contains an organic compound that emits green phosphorescence as a light-emitting material. The EL layer 103f and the third EL layer 103g contain the first organic EL layer as a host material in addition to the light-emitting material. The composition further includes a second organic compound, and the first organic compound and the second organic compound are The organic compound forms an exciplex, and energy is transferred from the exciplex to the luminescent material. In addition, it is preferable that the emission spectrum of the exciplex and the absorption band on the longest wavelength side of the luminescent material are The overlapping structure is more preferable since it allows for efficient energy transfer.

[0084] In the light emitting device having this configuration, the second EL layer 103f and the third EL layer 103g It is preferable that both layers have a higher electron transporting property than a hole transporting property. By this, only blue fluorescence is obtained from the first light-emitting element, and blue fluorescence is obtained from the second and third light-emitting elements. Only green phosphorescence can be obtained from each optical element. The first electrode is a cathode, the second When the electrode is an anode, the first EL layer 103e is an electron transport layer in FIG. 5B, the hole injection layer 114 and the electron injection layer 118. The fourth EL layer 103h is the same as the hole injection layer 114 and the electron injection layer 118 in FIG. The second EL layer 103f and the third EL layer 103g correspond to an electron transport layer 115. It is preferable that the layer has a higher hole transporting property than a electron transporting property.

[0085] In FIG. 1C, the second EL layer 103f is formed before the third EL layer 103g. The third EL layer 103g is formed before the second EL layer 103f. In this case, the second EL layer 103f and the third EL layer 103 It is preferable that both of the layers g have a higher hole transporting property than an electron transporting property. When the second electrode is an anode, the second EL layer 103f and the third EL layer 103g are both It is preferable that the layer has an electron transporting property higher than a hole transporting property.

[0086] The light emitted from the third light emitting element is incident on the color conversion layer 106R. In addition, the light emitted from the first light-emitting element and the light emitted from the second light-emitting element can be mixed. The light emitted from each of the elements may be emitted outside the light-emitting device through a color filter. When no color filter is used, light can be obtained with good efficiency. Light emission with good color purity can be obtained.

[0087] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and In this study, we consider the external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0088] First, in a light-emitting device having a different configuration from the above-mentioned configuration, which does not use a color conversion layer, The structure of the light-emitting element in the light-emitting device is the same as that shown in FIG. The structure of each light-emitting element in the light-emitting device is the same as that of the red, green, and blue light-emitting elements in the light-emitting device. To obtain the three colors efficiently, light with intensity at the wavelengths corresponding to red, green, and blue is usually used. In order to balance practicality and efficiency, blue fluorescent materials and red fluorescent materials are required. If a phosphorescent material and a green phosphorescent material are used, the second EL layer 103f may contain a blue fluorescent material. In addition, the third EL layer 103g may be made of a red phosphorescent material and a green phosphorescent material. The light element and the third light-emitting element produce a composite light of red and green light, so the second light-emitting element The optical element emits green light by emitting light outside the light-emitting device through a green color filter. The third light emitting element emits light to the outside of the light emitting device through a red color filter. This produces red light.

[0089] In a light-emitting device having such a structure, the internal quantum efficiency of each light-emitting layer is calculated by the following equation: Assuming that the phosphorescent layer is 100%, the external quantum efficiency of the blue pixel is 25×χ A % (without color filter, 25×χ with color filter) CF %),green The external quantum efficiency of the red and red pixels is 50×χ CFThe result is %.

[0090] Next, considering the present light-emitting device having the configuration shown in FIG. 1(C), the external quantum efficiency of the blue pixel The rate is 25×χ A % (without color filter, 25×χ with color filter) CF %), and the external quantum efficiency of the green pixel is 100×χ A % (Without color filter. When using a Lar filter, the value is 100×χ CF %), and the external quantum efficiency of the red pixel is 100×χ C C %. In this way, by using the structure of one embodiment of the present invention, the luminous efficiency is very high. Thus, a light emitting device with good properties can be obtained.

[0091] Here, when comparing the external quantum efficiency of the green pixel in the conventional configuration and the present configuration, In adulthood, it is 50×χ CF %, whereas in this configuration it is 100×χ A %, more than twice as effective In addition, the external quantum efficiency of the red pixel in the conventional configuration and the present configuration was compared. In the conventional configuration, CF %, whereas in this configuration it is 100×χ CC % and Therefore, if the transmittance of the color filter and the PL quantum efficiency of the color conversion layer are the same, the efficiency is doubled. This suggests that the PL quantum efficiency of the color conversion layer is 50 times the transmittance of the color filter. % or more, it is possible to obtain a red pixel with a better external quantum efficiency than conventional red pixels. As a result, a light emitting device with low power consumption can be provided.

[0092] In addition, as shown in FIG. 2C, a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1C. The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. The EL layer of the second configuration is disposed on the fourth light emitting element. The external quantum efficiency of the yellow pixel is Since it is obtained by color conversion of green phosphorescence, 100×χ CC The result is %.

[0093] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0094] <Conversion from blue fluorescent single element and green phosphorescent single element (one-time coating) 2> FIG. 1(D) shows an embodiment of the present invention using a single blue fluorescent element and a single green phosphorescent element. The light-emitting device shown in FIG. Each of the light emitting devices has a first light emitting element to a third light emitting element, and a substrate 100 and a sealing substrate 10 1, first electrodes 102B, 102G, 102R, second electrode 104, black matrix The color conversion layer 105 and the color conversion layer 106R are similar to those in the light emitting device shown in FIG. is omitted.

[0095] In the light-emitting device shown in FIG. 1D, the first light-emitting element has an EL layer of the third configuration, The second light-emitting element and the third light-emitting element have an EL layer of the fourth configuration.

[0096] The EL layer of the third configuration includes a first EL layer 103i, a second EL layer 103j, and a fourth EL layer The EL layer of the fourth configuration is a first EL layer 103i, A structure in which a second EL layer 103j, a third EL layer 103k, and a fourth EL layer 103m are laminated It is a completion.

[0097] When the first electrode is an anode and the second electrode is a cathode, the first EL layer 103i is These layers correspond to the hole injection layer 114 and the hole transport layer 115 in (B). The EL layer 103j corresponds to the first light-emitting layer 116d-1 in FIG. The third EL layer 103k corresponds to the second light-emitting layer 116d-2 in FIG. The fourth EL layer 103m corresponds to the electron transport layer 117 and the electron injection layer 118 in FIG. 5(B). That is, the EL layer of the fourth configuration corresponds to the EL layer 103d in FIG. The EL layer of the third configuration has a structure similar to that of the EL layer 103a in FIG. It becomes.

[0098] The EL layer of the third configuration and the EL layer of the fourth configuration can be formed by a single coating process. By simply applying the paint once, a single layer of a fluorescent light-emitting layer and a phosphorescent light-emitting layer can be produced. As compared with a light emitting device having a conventional structure, light emission can be achieved with a very high efficiency.

[0099] The second EL layer 103j contains an organic compound that emits blue fluorescence as a light-emitting material. The third EL layer 103k contains an organic compound that emits green phosphorescence as a light-emitting material. The EL layer 103j and the third EL layer 103k contain a first organic EL layer as a host material in addition to the light-emitting material. The composition further includes a second organic compound, and the first organic compound and the second organic compound are The organic compound forms an exciplex, and energy transfer occurs from the exciplex to the light-emitting material. In addition, it is preferable that the emission spectrum of the exciplex and the longest wavelength side of the luminescent material are Overlapping absorption bands are a more preferable configuration because they allow for efficient energy transfer. do.

[0100] In the light-emitting device, the second EL layer 103j and the third EL layer 103k are It is preferable that the layer has a higher hole transporting property than an electron transporting property. As a result, only blue fluorescence is obtained from the first light-emitting element, and only blue fluorescence is obtained from the second and third light-emitting elements. Only green phosphorescence can be obtained from each of the electrodes. When the electrode is an anode, the first EL layer 103i is the electron transport layer 11 in FIG. 7 and the electron injection layer 118, and the fourth EL layer 103m are the same as the hole injection layer 114 and the The second EL layer 103j and the third EL layer 103k correspond to a hole transport layer 115. It is preferable to use a layer having a higher electron transporting property than a lower electron conducting property.

[0101] In FIG. 1D, the second EL layer 103j is formed before the third EL layer 103k. However, the third EL layer 103k is formed before the second EL layer 103j. In this case, the second EL layer 103j and the third EL layer 103 It is preferable that k is a layer having a higher hole transporting property than an electron transporting property. When the second electrode is an anode, the second EL layer 103j and the third EL layer 103k are connected in common. It is preferable that the layer has an electron transporting property higher than a hole transporting property.

[0102] The light emitted from the third light emitting element is incident on the color conversion layer 106R. In addition, the light emitted from the first light-emitting element and the light emitted from the second light-emitting element can be mixed. The light emitted from each of the elements may be emitted outside the light-emitting device through a color filter. When no color filter is used, light can be obtained with good efficiency, but when a color filter is used, Light emission with good color purity can be obtained.

[0103] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and In this study, we consider the external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0104] First, in a light-emitting device having a different configuration from the above-mentioned configuration, which does not use a color conversion layer, The structure of the light-emitting element in the light-emitting device is shown in FIG. The structure of each light-emitting element in the light-emitting device is the same as that of the red, green, and blue light-emitting elements in the light-emitting device. To obtain the three colors efficiently, light with intensity at the wavelengths corresponding to red, green, and blue is usually used. In order to balance practicality and efficiency, blue fluorescent materials and red fluorescent materials are required. If a phosphorescent material and a green phosphorescent material are used, the second EL layer 103j may contain a blue fluorescent material. It is preferable to use a red phosphorescent material and a green phosphorescent material in the third EL layer 103k. The second and third light-emitting elements produce a composite light of red and green light, The second light emitting element emits green light by emitting light to the outside of the light emitting device through a green color filter. The third light emitting element emits light to the outside of the light emitting device through a red color filter. When released, red light is obtained.

[0105] In a light-emitting device having such a structure, the internal quantum efficiency of each light-emitting layer is calculated by the following equation: Assuming that the phosphorescent layer is 100%, the external quantum efficiency of the blue pixel is 25×χ A % (without color filter, 25×χ with color filter) CF %),green The external quantum efficiency of the red and red pixels is 50×χ CF The result is %.

[0106] Next, considering the present light-emitting device having the configuration shown in FIG. 1(D), the external quantum efficiency of the blue pixel The rate is 25×χ A % (without color filter, 25×χ with color filter) CF %), and the external quantum efficiency of the green pixel is 100 × χ A % (Without color filter. If you use a color filter, the value is 100×χ CF %), and the external quantum efficiency of the red pixel is 100× χ CC %. Thus, by using the configuration of one embodiment of the present invention, it is possible to obtain a very high light emission. It is possible to obtain a light emitting device with good efficiency.

[0107] Here, when comparing the external quantum efficiency of the green pixel in the conventional configuration and the present configuration, In adulthood, it is 50×χ CF %, whereas in this configuration it is 100×χ A %, more than twice as effective In addition, the external quantum efficiency of the red pixel in the conventional configuration and the present configuration was compared. In the conventional configuration, CF %, whereas in this configuration it is 100×χ CC % and Therefore, if the transmittance of the color filter and the PL quantum efficiency of the color conversion layer are the same, the efficiency is doubled. This suggests that the PL quantum efficiency of the color conversion layer is 50 times the transmittance of the color filter. % or more, it is possible to obtain a red pixel with a better external quantum efficiency than conventional red pixels. As a result, a light emitting device with low power consumption can be provided.

[0108] As shown in FIG. 2(D), a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1(D). The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. The fourth light emitting element has an EL layer of a fourth configuration. The light emitted from the fourth light emitting element is converted into a color conversion layer 106. The external quantum efficiency of the yellow pixel is Since it is obtained by color conversion of green phosphorescence, 100×χ CC The result is %.

[0109] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0110] <Conversion of blue fluorescence and yellow phosphorescence from a tandem device> FIG. 3(A) shows a light-emitting device according to one embodiment of the present invention using a tandem element of blue fluorescence and yellow phosphorescence. The light emitting device has at least a first light emitting element and a second light emitting element on a substrate 100. The first light emitting element, the second light emitting element, and the third light emitting element are provided. The first electrode 104 is common to both light emitting elements, and the first electrode is different. B, the second light emitting element has a first electrode 102G, and the third light emitting element has a first electrode 102R. The sealing substrate 101 has a black matrix 105 and a color filter. The color filter 107B, the color conversion layer 106G, and the color conversion layer 106R are provided. The color conversion layer 106G is a color filter that transmits green light. The color conversion layer 106R contains a color conversion material that emits red light. It contains a color-changing substance that changes the color of the light.

[0111] In FIG. 3A, the EL layer 103 is a tandem type EL layer, typically a tandem type EL layer, as shown in FIG. The tandem structure is an EL layer having a first light-emitting unit 103b and a second light-emitting unit 103c. The light-emitting unit 103c is laminated with the light-emitting unit 103b via the intermediate layer 109, which is a charge generating layer. Each light-emitting unit has a first electrode 102 as an anode and a second electrode 104 as a cathode. The hole injection layer 114 and the hole transport layer 115 are formed in this order from the first electrode 102 (here, the anode) side. A typical structure includes a light-emitting layer 116, an electron transport layer 117, an electron injection layer 118, etc. In such a structure, the light-emitting material may be contained in the light-emitting layer 116. When the electrode 102 is used as a cathode and the second electrode 104 is used as an anode, the stacking order of the EL layers can be reversed. Note that the EL layer 103 is common to the first to third light-emitting elements.

[0112] Either the first light-emitting unit 103b or the second light-emitting unit 103c is blue. The EL layer 103 emits blue light and the other emits yellow phosphorescence. The light obtained is a combination of the fluorescent light and the yellow phosphorescence. The organic electroluminescent device has a first organic compound as a host material in addition to the light-emitting material. The first organic compound and the second organic compound form an exciplex, and the exciplex is It is preferable that energy transfer occurs from the exciplex to the light-emitting material. When the emission spectrum overlaps with the absorption band at the longest wavelength of the luminescent material, energy transfer is efficient. This is a preferred configuration since it allows for movement.

[0113] The light emitted from the first light emitting element is emitted outside the light emitting device through the color filter 107B. The light emitted from the second light emitting element is incident on color conversion layer 106G. The third light emitting element is excited by the incident light and emits green light. The light emitted from the cathode 106 is incident on color conversion layer 106R, which then emits red light.

[0114] In this light-emitting device, blue fluorescence and yellow phosphorescence are synthesized from the EL layer 103. However, the color conversion layer 106G cannot absorb yellow light, so the resonant structure It is preferable to use a color filter to remove yellow light incident on color conversion layer 106G. When forming a resonant structure, it is sufficient to form it so as to amplify blue light. As shown in FIG. 3A, a transparent conductive film (transparent conductive film 102B) having a desired thickness is formed on the first electrode. t, transparent conductive film 102Gt, and transparent conductive film 102Rt) are formed. In order to remove light that cannot be absorbed by the first and third light emitting elements, It is not necessary to form a resonant structure, but if a resonant structure is formed for other purposes, the first The light emitting element is arranged to amplify blue light, and the third light emitting element is arranged to amplify yellow light. The bright conductive film 102Bt and the transparent conductive film 102Rt may be formed separately.

[0115] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and In this study, we consider the external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0116] First, the external quantum efficiency of each color pixel in a light-emitting device having a different configuration from the above configuration will be described. A trial calculation is performed. A light-emitting device using a normal tandem element can efficiently obtain the three colors of red, green, and blue. For this purpose, it is effective to use luminescent materials that exhibit the respective luminescent wavelengths, and this is both practical and effective. Due to the balance between the efficiency and the blue fluorescent material, the red phosphorescent material and the green phosphorescent material are often used. The structure is the same as that shown in Fig. 5(A), and the light-emitting layer of one of the light-emitting units emits blue fluorescent light. The fluorescent light-emitting layer of the other light-emitting unit is made of a red phosphorescent material and a green phosphorescent material. A phosphorescent material is used to form a phosphorescent light-emitting layer.

[0117] In a light-emitting device having such a structure, the internal quantum efficiency of each light-emitting layer is Assuming that the emissive layer is 25% and the phosphorescent emissive layer is 100%, the external quantum efficiency of the blue pixel is 25 ×χ CF %, and the external quantum efficiency of the green and red pixels is 50×χ CF % (phosphorescent layer The excitons are shared between the red phosphorescent material and the green phosphorescent material. For simplicity, the distribution is assumed to be the same. etc.).

[0118] Next, a light emitting device having the above configuration (the configuration of FIG. 3(A)) will be considered. External quantum efficiency of blue pixel is 25×χ CF %, green pixels are 25×χ CC %, red pixels are 12 5×χ CC % (When no resonant structure is formed. When a resonant structure is formed, blue light is attenuated. So it's 100×χ CC %). In this way, by using this light-emitting device, A light emitting element having very good light emission efficiency can be obtained.

[0119] Here, when comparing the external quantum efficiency of the red pixel in the conventional configuration and the present configuration, In adulthood, it is 50×χ CF %, whereas in this configuration it is 125×χ CC %, and the color filter If the transmittance of the filter and the PL quantum yield of the color conversion layer are the same, a 2.5-fold increase in efficiency is expected. From this, if the PL quantum efficiency of the color conversion layer is 40% or more of the transmittance of the color filter, This makes it possible to obtain a red pixel with better external quantum efficiency than a conventional red pixel.

[0120] In addition, as shown in FIG. 4(A), a fourth light-emitting element is added as a yellow pixel to the configuration of FIG. 3(A). The fourth light emitting element may have a structure in which the first electrode 102Y and the second electrode 104 and an EL layer including a first light-emitting unit 103b and a second light-emitting unit 103c between them. It is also possible to configure a resonant structure corresponding to yellow light emission. In this case, a transparent conductive A film 102Yt may be formed. The light emitted from the fourth light emitting element is a color filter. Since the light is emitted to the outside of the light-emitting device through the photodiode 107Y, the external quantum efficiency of the yellow pixel is 100 ×χ CF %. The color filter 107Y may be replaced with a yellow color conversion layer 106Y. In this case, the external quantum efficiency of the yellow pixel is 125×χ CC The result is %.

[0121] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0122] In the case of the configuration of FIG. 4(A), white light can be expressed using only red, blue, and yellow light. Therefore, the efficiency of the green light has little effect on power consumption. %, the first color conversion layer provided in the red pixel, color conversion layer 106R If the PL quantum yield of the device is greater than 40%, it is considered to be a more efficient light-emitting device than conventional light-emitting devices. In addition, when a resonant structure is formed, the PL quantum of the color conversion layer 106R can be obtained. The yield is greater than 50%, which makes it possible to obtain a light-emitting device with higher efficiency than conventional light-emitting devices. This can be done.

[0123] <Conversion of blue fluorescence and yellow phosphorescence from a single element> FIG. 3B shows light emission of one embodiment of the present invention using a single element that utilizes blue fluorescence and yellow phosphorescence. The light-emitting device has at least a first light-emitting element similar to the light-emitting device shown in FIG. The display device includes a first light emitting element, a second light emitting element, a third light emitting element, a substrate 100, a sealing substrate 101, a third light emitting element, and a First electrodes 102B, 102G, 102R, second electrode 104, black matrix 105 3A, color conversion layer 106R, color conversion layer 106G, and color filter 107B are also Since this light emitting device is similar to that shown in FIG.

[0124] In FIG. 3B, the EL layer 103d is a thin film EL layer, as shown in FIG. The EL layer has a group structure. The first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 The electrodes may be formed in contact with each other, or a separation layer having a thickness of more than 0 nm and less than 20 nm may be provided between the electrodes. The thickness of the separation layer is preferably 1 nm or more and 10 nm or less. The first light emitting element to the third light emitting element have a common element 103d.

[0125] In this configuration, the first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 in FIG. One of them emits blue fluorescence and the other emits yellow phosphorescence. The EL layer 103d emits light that is a combination of blue fluorescence and yellow phosphorescence. The first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 contain a host material and The first light-emitting layer 116d-1 and the second light-emitting layer 11 6d-2 further includes a second organic compound, and the first organic compound and the second organic compound It is preferable that the compound forms an exciplex, and at this time, energy is transferred from the exciplex to the light-emitting material. In addition, the emission spectrum of the exciplex and the most suitable luminescent material are It is more preferable that the absorption bands on the long wavelength side overlap, since this allows for efficient energy transfer. The composition is as follows.

[0126] The light emitted from the first light emitting element is emitted outside the light emitting device through a blue color filter 107B. The light emitted from the second light emitting element is incident on color conversion layer 106G, and the light emitted from the second light emitting element is incident on color conversion layer 106G. The third emitter, 06G, is excited by the incident light and emits green light. The light emitted from the optical element enters color conversion layer 106R, which emits red light.

[0127] In this light-emitting device, blue fluorescence and yellow fluorescence are emitted from the EL layer 103 in the same manner as in FIG. The color conversion layer 106G cannot absorb yellow light, so the color conversion layer 106G cannot absorb yellow light. Therefore, a resonant structure or a color filter is used to remove the yellow light incident on the color conversion layer 106G. When forming a resonant structure, it is preferable to form it so as to amplify blue light. The resonator structure is formed by forming a transparent conductive film ( Forming the transparent conductive film 102Bt, the transparent conductive film 102Gt, and the transparent conductive film 102Rt In addition, the first light emitting element and the third light emitting element cannot absorb the light. It is not necessary to form a resonant structure for the purpose of removing light, but it is possible to form a resonant structure for other purposes. In this case, the first light emitting element is configured to amplify blue light and the third light emitting element is configured to amplify yellow light. The transparent conductive film 102Bt and the transparent conductive film 102Rt may be formed so as to amplify the stomach.

[0128] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and The external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0129] First, the external quantum efficiency of each pixel in a light-emitting device having a different configuration from the above The structure of the light-emitting element is shown in Figure 5(B), where two light-emitting layers are in one light-emitting unit. Assume that the device has a single-structure EL layer provided adjacent to each other. In order to efficiently obtain the three colors of red, green, and blue without using a color conversion layer in a light-emitting element having In general, it is effective to use luminescent materials that exhibit the respective luminescent wavelengths, and this is advantageous in terms of practicality and efficiency. In view of the balance between these two, blue fluorescent materials, red phosphorescent materials and green phosphorescent materials are often used. Either the first light-emitting layer 116d-1 or the second light-emitting layer 116d-2 is a fluorescent light-emitting layer, and the other If one of the layers is a phosphorescent layer, blue fluorescent material is used in one layer and red phosphorescent material is used in the other layer. The internal quantum efficiency of each light-emitting layer is calculated by dividing the total number of layers by the number of fluorescent light-emitting layers. Assuming that the light emitting layer is 25% and the phosphorescent layer is 100%, the exciton distribution is blue, green, and red, respectively. If the ratio is 1:1:1, the external quantum efficiency of the blue pixel is 8.3 × χ CF %, Green pixels and The external quantum efficiency of the red pixel is 33×χ CF The result is %.

[0130] Next, consider a light-emitting device having the configuration shown in FIG. 3(B). In addition to the same assumptions, The distribution of the molecules is assumed to be 1:1 between blue and yellow, and the PL quantum yield of the color conversion layer is assumed to be 100%. Then, the external quantum efficiency of each pixel is 12.5×χ for the blue pixel. CF %, green pixels are 12 .5×χ CC %, red pixels are 62.5×χ CC % (When no resonant structure is used. Resonant structure When the blue light is attenuated, the blue light is reduced by 50×χ CC %). Thus, the present invention By using the configuration of one embodiment of the present invention, a light-emitting element having a good external quantum efficiency of a red pixel can be obtained. It will be possible to do so.

[0131] Here, the external quantum efficiency of the blue pixel in the conventional configuration is 8.3 × χ CF Even though it is % In contrast, this configuration is 12.5×χ CF %, which is expected to improve efficiency by about 1.5 times. In the original configuration, the CF %, while this configuration is 62.5×χ CC % If the transmittance of the color filter and the PL quantum efficiency of the color conversion layer are the same, the PL quantum efficiency is approximately 1.88 times higher. This means that the PL quantum efficiency of the color conversion layer in the red pixel is - If the filter transmittance is 53.3% or more, the external quantum efficiency is better than that of conventional red pixels. Therefore, it is possible to obtain a red pixel of 1000 .mu.m.

[0132] As shown in FIG. 4B, a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 3B. The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. The fourth light emitting element has an EL layer 103d. The light emitted from the fourth light emitting element is reflected by a color filter 10. Since the light is emitted outside the light-emitting device via 7Y, the external quantum efficiency of the yellow pixel is 50×χ CF %. When forming a resonant structure, it is sufficient to form it so as to amplify yellow light. Resonant The structure is as shown in FIG. 4(B), in which a transparent conductive film 102Yt having a desired thickness is formed on a first electrode. The color filter 107Y can be provided by forming a yellow color conversion layer. 106Y, in which case the external quantum efficiency of the yellow pixel is 62.5×χ CC %and Become

[0133] The light-emitting device having such a configuration can display an image in four colors: red, green, blue, and yellow. It has excellent reproducibility. In addition, yellow light has high visibility, so it is possible to reduce power consumption. become.

[0134] In the case of the configuration of FIG. 4(B), white light can be expressed using only red, blue, and yellow light. Therefore, the efficiency of green light has little effect on power consumption. Therefore, the external quantum efficiency of the yellow pixel is 50×χ CF %, the first color conversion layer provided in the red pixel The PL quantum yield of the 106R layer is greater than 53.3% of the transmittance (%) of the red color filter. If the above-mentioned method can be used, it is possible to obtain a light emitting device having a higher efficiency than a conventional light emitting device. When a resonant structure is formed, the PL quantum efficiency of the color conversion layer 106R is 1 / 100 that of the red color filter. With a transmittance of more than 66%, this light-emitting device is more efficient than conventional light-emitting devices. can be obtained.

[0135] <Conversion from blue fluorescent single element and yellow phosphorescent single element (one-time coating) 1> FIG. 3C shows one embodiment of the present invention using a single blue fluorescent element and a single yellow phosphorescent element. The light-emitting device shown in FIG. Each of the light emitting devices has a first light emitting element to a third light emitting element, and a substrate 100 and a sealing substrate 10 1, first electrodes 102B, 102G, 102R, second electrode 104, black matrix The color conversion layer 105, the color conversion layer 106G, and the color conversion layer 106R are the same as those in the light emitting device shown in FIG. Since they are similar, the explanation will be omitted.

[0136] In the light emitting device shown in FIG. 3C, the first light emitting element and the second light emitting element have the fifth configuration. The third light-emitting element has an EL layer of the sixth configuration, and the third light-emitting element has an EL layer of the sixth configuration.

[0137] The fifth EL layer structure includes a first EL layer 103e, a second EL layer 103f, and a third EL layer 103c. The sixth EL layer is a laminate of a fourth EL layer 103g and a fourth EL layer 103h. A structure in which a first EL layer 103e, a third EL layer 103g, and a fourth EL layer 103h are laminated It is a completion.

[0138] When the first electrode is an anode and the second electrode is a cathode, the first EL layer 103e is These layers correspond to the hole injection layer 114 and the hole transport layer 115 in (B). The EL layer 103f corresponds to the first light-emitting layer 116d-1 in FIG. The third EL layer 103g corresponds to the second light-emitting layer 116d-2 in FIG. The fourth EL layer 103h corresponds to the electron transport layer 117 and the electron injection layer 118 in FIG. 5(B). That is, the EL layer of the fifth configuration corresponds to the EL layer 103d in FIG. The EL layer of the sixth configuration has a structure similar to that of the EL layer 103a in FIG. It becomes.

[0139] The second EL layer 103f contains an organic compound that emits blue fluorescence as a light-emitting material. The third EL layer 103g contains an organic compound that emits yellow phosphorescence as a light-emitting material. The EL layer 103f and the third EL layer 103g contain a first active material as a host material in addition to the light-emitting material. The composition further includes a second organic compound, and the first organic compound and the second organic compound are The organic compound forms an exciplex, and energy is transferred from the exciplex to the luminescent material. In addition, it is preferable that the emission spectrum of the exciplex and the absorption spectrum of the luminescent material on the longest wavelength side are Overlapping bands are the more preferred configuration as they allow for more efficient energy transfer.

[0140] In the light emitting device having this configuration, the second EL layer 103f and the third EL layer 103g It is preferable that both layers have a higher electron transporting property than a hole transporting property. By this, only blue fluorescence is obtained from the first light emitting element and the second light emitting element, and only blue fluorescence is obtained from the third light emitting element. Only yellow phosphorescence can be obtained from each optical element. The first electrode is a cathode and the second When the electrode is an anode, the first EL layer 103e is an electron transport layer in FIG. 5B, the hole injection layer 114 and the electron injection layer 118. The fourth EL layer 103h is the same as the hole injection layer 114 and the electron injection layer 118 in FIG. The second EL layer 103f and the third EL layer 103g correspond to an electron transport layer 115. For the same reasons as above, it is preferable to use a layer having a higher hole transporting property than a electron transporting property.

[0141] In FIG. 3C, the second EL layer 103f is formed before the third EL layer 103g. The third EL layer 103g is formed before the second EL layer 103f. In this case, the second EL layer 103f and the third EL layer 103 It is preferable that both of the layers g have a higher hole transporting property than an electron transporting property. When the second electrode is an anode, the second EL layer 103f and the third EL layer 103g are both It is preferable that the layer has an electron transporting property higher than a hole transporting property.

[0142] Blue light can be obtained from the first light-emitting element. By irradiating light to color conversion layer 106G, green light can be emitted from color conversion layer 106G. The light emitted from the third light emitting element is incident on the color conversion layer 106R to obtain red light. The light emitted from the first light emitting element is passed through a color filter. The light may be emitted outside the optical device. When the light is irradiated through the cathode, light having good color purity can be obtained.

[0143] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and The external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0144] First, the external quantum efficiency of each pixel in a light-emitting device having a different configuration from the above The structure of the light-emitting element in the light-emitting device is a first light-emitting element and a third light-emitting element. The element structure of the light emitting element in the light emitting device in FIG. Regarding the light-emitting element No. 2, the EL layer of the fifth configuration is shown in FIG. 3(C). In this device, the EL layer is of the sixth configuration.

[0145] In order to efficiently obtain the three colors of red, green, and blue in a light-emitting element having this structure, the following is usually required: It is possible to use light-emitting materials that emit light having intensities at wavelengths corresponding to red, green, and blue. Blue fluorescent materials, red phosphorescent materials, and green phosphorescent materials are effective and have a good balance between practicality and efficiency. A blue fluorescent material is often used for the second EL layer 103f, and a red fluorescent material is often used for the third EL layer 103c. It is preferable to use a red phosphorescent material and a green phosphorescent material for 103g. As a result, light that is a combination of red and green light is obtained from the second and third light-emitting elements. In the second pixel, the light is emitted to the outside of the light emitting device through a green color filter, and thus green light is emitted. In the third pixel, the light is emitted outside the light-emitting device through a red color filter. This results in red light.

[0146] Here, the distribution of excitons between the red phosphorescent material and the green phosphorescent material in the third EL layer Assuming that the ratio is 1:1, the external quantum efficiency of the blue pixel is 25×χ A % (no color filter When using a color filter, use 25×χ CF %), outside the green and red pixels The partial quantum efficiency is 50×χ CF % (using color filter).

[0147] Next, consider the light-emitting device having the configuration shown in FIG. 3(C). The external quantum efficiency of the blue pixel is 25×χ A % (without color filter, 25×χ with color filter) CF %), and the external quantum efficiency of the green pixel is 25×χ CC %, and the external quantum efficiency of the red pixel is 100×χ CC %. In this way, by using the configuration of one embodiment of the present invention, It is possible to obtain a light-emitting device having a better external quantum efficiency of the red pixel than a light-emitting device having a structure having a red pixel. You will be able to do it.

[0148] Here, when comparing the external quantum efficiency of the red pixel with the previously described configuration, In the configuration, 50×χ CF %, whereas in this configuration it is 100×χ CC %, and color If the transmittance of the filter and the PL quantum yield of the color conversion layer are the same, a two-fold increase in efficiency can be expected. This shows that the PL quantum efficiency of the color conversion layer is 50% or more of the transmittance of the color filter. This means that the red pixel has a better external quantum efficiency than the red pixel in the light-emitting device described above. This makes it possible to provide a light emitting device with low power consumption.

[0149] In addition, as shown in FIG. 4C, a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 3C. The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. The external quantum efficiency of the yellow pixel is 1 / 4 the EL layer of the fourth configuration. When the light emitted from the element is emitted to the outside of the light emitting device through the color filter 107Y, ×χ CF %, 100×χ when no color filter is installed A The result is %.

[0150] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0151] In the case of the configuration of FIG. 4(C), white light can be expressed using only red, blue, and yellow light. Therefore, the efficiency of green light has little effect on power consumption. This is why the efficiency of green pixels is reduced. However, the PL quantum efficiency of the color conversion layer 106R, which is the first color conversion layer provided in the red pixel, is red. If the transmittance of the color filter is 50% or more, the red light emission is equivalent to that of a conventional element. As a result, a light emitting device with good efficiency can be obtained.

[0152] The light emitting device having this configuration can achieve these effects with just one separate coating.

[0153] <Conversion from blue fluorescent single element and yellow phosphorescent single element (one-time coating) 2> FIG. 3D shows one embodiment of the present invention using a single blue fluorescent element and a single yellow phosphorescent element. The light-emitting device shown in FIG. Each of the light emitting devices has a first light emitting element to a third light emitting element, and a substrate 100 and a sealing substrate 10 1, first electrodes 102B, 102G, 102R, second electrode 104, black matrix The color conversion layer 105, the color conversion layer 106G, and the color conversion layer 106R are the same as those in the light emitting device shown in FIG. Since they are similar, the explanation will be omitted.

[0154] In the light emitting device shown in FIG. 3D, the first light emitting element and the second light emitting element have the seventh configuration. the third light-emitting element has an EL layer of the eighth configuration; and the third light-emitting element has an EL layer of the eighth configuration.

[0155] The seventh EL layer structure includes a first EL layer 103i, a second EL layer 103j, and a fourth EL layer 103c. The eighth EL layer is a laminate of a first EL layer 103i, a second EL layer 103m, and a third EL layer 103m. A structure in which a second EL layer 103j, a third EL layer 103k, and a fourth EL layer 103m are laminated. It is.

[0156] When the first electrode is an anode and the second electrode is a cathode, the first EL layer 103i is These layers correspond to the hole injection layer 114 and the hole transport layer 115 in (B). The EL layer 103j corresponds to the first light-emitting layer 116d-1 in FIG. The third EL layer 103k corresponds to the second light-emitting layer 116d-2 in FIG. The fourth EL layer 103m corresponds to the electron transport layer 117 and the electron injection layer 118 in FIG. 5(B). That is, the EL layer of the seventh configuration corresponds to the EL layer 103a in FIG. The EL layer of the eighth configuration has a structure similar to that of the EL layer 103d in FIG. It becomes.

[0157] The second EL layer 103j contains an organic compound that emits blue fluorescence as a light-emitting material. The third EL layer 103k contains an organic compound that emits yellow phosphorescence as a light-emitting material. In addition to these light-emitting materials, the EL layer 103j and the third EL layer 103k contain a second EL layer as a host material. The composition further includes a first organic compound and a second organic compound. The organic compound of formula 2 forms an exciplex, and energy is transferred from the exciplex to the light-emitting material. In addition, the emission spectrum of the exciplex and the longest wavelength side of the luminescent material are preferably This is a preferable configuration because the overlap of the absorption bands enables efficient energy transfer. .

[0158] In the light-emitting device having this configuration, the second EL layer 103j and the third EL layer 103k It is preferable that both of the layers have a hole transporting property rather than an electron transporting property. By this, only blue fluorescence is obtained from the first light emitting element and the second light emitting element, and only blue fluorescence is obtained from the third light emitting element. Only yellow phosphorescence can be obtained from each optical element. The first electrode is a cathode and the second When the electrode is an anode, the first EL layer 103i is an electron transport layer in FIG. 5B, the hole injection layer 114 and the electron injection layer 118. The fourth EL layer 103m is the same as the hole injection layer 114 and the electron injection layer 118 in FIG. The second EL layer 103j and the third EL layer 103k correspond to a hole transport layer 115. For the same reasons as above, it is preferable for the layer to have a higher electron transporting property than a hole transporting property.

[0159] In FIG. 3D, the second EL layer 103j is formed before the third EL layer 103k. However, the third EL layer 103k is formed before the second EL layer 103j. In this case, the second EL layer 103j and the third EL layer 103 It is preferable that k is a layer having a higher hole transporting property than an electron transporting property. When the second electrode is an anode, the second EL layer 103j and the third EL layer 103k are connected in common. It is preferable that the layer has an electron transporting property higher than a hole transporting property.

[0160] The first light-emitting element can emit blue light. The second light-emitting element emits colored light. By making the light incident on the color conversion layer 106G, green light can be obtained from the color conversion layer 106G. By making the light emitted from the third light emitting element incident on the color conversion layer 106R, red light can be obtained. The light emitted from the first light emitting element passes through a color filter and then exits the light emitting device. If the light is not emitted through a color filter, it is possible to obtain light with good efficiency. When the light is passed through the reflective layer, light with good color purity can be obtained.

[0161] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and The external quantum efficiency of each pixel in a light-emitting device having the above-mentioned configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, It shall be so.

[0162] First, the external quantum efficiency of each pixel in a light-emitting device having a different configuration from the above The structure of the light emitting element in the light emitting device of this configuration is a first light emitting element and a third light emitting element. The optical element has the same element structure as the light-emitting element in the light-emitting device shown in FIG. The second light-emitting element has an EL layer of the seventh configuration in FIG. 3(D), but This is considered to be the eighth EL layer in the device.

[0163] In a light-emitting device having this structure, in order to efficiently obtain the three colors of red, green, and blue, it is usually It is effective to use luminescent materials that exhibit the respective luminescent wavelengths, and it is possible to achieve both practicality and efficiency. Therefore, blue fluorescent materials, red phosphorescent materials, and green phosphorescent materials are often used. In the device, a blue fluorescent material is used for the second EL layer 103j, and a red fluorescent material is used for the third EL layer 103k. Colored and green phosphorescent materials may be used.

[0164] The third EL layer 103k of the eighth configuration of the EL layer contains red and green phosphorescent materials. Therefore, the second and third light emitting elements produce a composite light of red and green light. Therefore, the second light emitting element emits light to the outside of the light emitting device through a green color filter. The third light-emitting element emits light through a red color filter. Red light is obtained by emitting the light to the outside of the device.

[0165] In the light-emitting device having the above configuration, the distribution of excitons in the third EL layer 103k is Assuming a 1:1 ratio between red and green phosphorescent materials, the external quantum efficiency of the blue pixel is is 25×χ A % (when no color filter is used, 25×χ when a color filter is used) CF % ), and the external quantum efficiency of the green and red pixels is 50 × χ CF % or less.

[0166] Next, consider the light-emitting device having the configuration shown in FIG. 3(D). The external quantum efficiency of the blue pixel is 25×χ A % (without color filter, 25×χ with color filter) CF %), and the external quantum efficiency of the green pixel is 25×χ CC %, and the external quantum efficiency of the red pixel is 100×χ CC %. In this way, by using the configuration of one embodiment of the present invention, It is possible to obtain a light emitting device with good partial quantum efficiency.

[0167] Here, when comparing the external quantum efficiency of the red pixel in the conventional configuration and the present configuration, In adulthood, it is 50×χ CF %, whereas in this configuration it is 100×χ CC %, and the color filter If the transmittance of the filter and the PL quantum yield of the color conversion layer are the same, a two-fold improvement in efficiency can be expected. From this, if the PL quantum efficiency of the color conversion layer is 50% or more of the transmittance of the color filter, It is now possible to create red pixels with better external quantum efficiency than conventional red pixels, and the power consumption is Therefore, it is possible to provide a light emitting device having a small size.

[0168] As shown in FIG. 4D, a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 3D. The fourth light-emitting element is disposed between the first electrode 102Y and the second electrode 104. The external quantum efficiency of the yellow pixel is 4.1 times that of the fourth emission. When the light emitted from the element is emitted to the outside of the light emitting device through the color filter 107Y, ×χ CF %, 100×χ when no color filter is installed A The result is %.

[0169] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. Excellent color reproducibility. Also, yellow has high visibility, so it is possible to reduce power consumption. do.

[0170] In the case of the configuration of FIG. 4(D), white light can be expressed using only red, blue, and yellow light. Therefore, the efficiency of green light has little effect on power consumption. This is why the efficiency of green pixels is reduced. However, the PL quantum efficiency of the color conversion layer 106R, which is the first color conversion layer provided in the red pixel, is red. If the transmittance of the color filter is 50% or more, blue and red light can be emitted by conventional devices. Thus, a light emitting device with good efficiency can be obtained.

[0171] The light emitting device having this configuration can achieve these effects with just one separate coating.

[0172] The color conversion layers 106R, 106G, and 106Y used in the above-mentioned light emitting device are Any device that can convert light of the desired wavelength with the desired efficiency can be used. Representative examples include a color conversion layer using a fluorescent dye or a color conversion layer using quantum dots. The color conversion layer using quantum dots is easy to use because it can convert a wide range of light wavelengths. In addition, the spectrum of the converted light is sharp, so light with good color purity can be produced. This is a preferred configuration because it is possible to obtain a light emitting device with good color reproducibility. .

[0173] <Light-emitting element> Next, an example of a light-emitting element according to one embodiment of the present invention will be described with reference to FIGS. This will be explained in detail below.

[0174] The light-emitting element used in this embodiment is composed of a first electrode 102 and a second electrode 104. A pair of electrodes and an EL layer 103 ( The first electrode 102 is made up of an EL layer 103a and an EL layer 103d. In the following description, the first electrode 102 functions as an anode and the second electrode 104 functions as a cathode. do.

[0175] Since the first electrode 102 functions as an anode, it is required to use a material having a large work function (specifically, 4.0 e V or higher) metals, alloys, conductive compounds, and mixtures thereof. Specifically, for example, indium oxide-tin oxide (ITO) is in Oxide), indium oxide-tin oxide containing silicon or silicon oxide, Indium oxide - zinc oxide, tungsten oxide and indium oxide containing zinc oxide ( These conductive metal oxide films are usually formed by sputtering. The film is formed by the sol-gel method, but it may be formed by applying the sol-gel method. Indium oxide-zinc oxide is a material in which 1 to 20 wt% of zinc oxide is mixed with indium oxide. There is also a method of forming the film by sputtering using a target containing the oxide. Indium oxide containing tungsten and zinc oxide (IWZO) is In contrast, tungsten oxide was 0.5 to 5 wt% and zinc oxide was 0.1 to 1 wt%. It can also be formed by sputtering using a gold (Au) target. Platinum (Pt), Nickel (Ni), Tungsten (W), Chromium (Cr), Molybdenum ( Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or metal Nitrides of materials such as titanium nitride, etc. Graphene can also be used. A composite material to be described later is used for the layer in contact with the first electrode 102 in the EL layer 103. This makes it possible to select an electrode material regardless of the work function.

[0176] The EL layer 103 (or the EL layer 103d or the EL layer 103a) has a laminated structure and includes a hole injection layer, A hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, a carrier block layer, an intermediate layer, etc. are appropriately combined. In this embodiment, the EL layer 103 (or the EL layer 103 d, the EL layer 103a) is basically composed of a hole-injecting layer 114, a hole transport layer 115, a light emitting layer 116, an electron transport layer 117, and an electron injection layer 118. Specific examples of materials constituting each layer are shown below.

[0177] The hole injection layer 114 is a layer containing a substance with a high hole injection property. Use of tungsten oxide, manganese oxide, etc. In addition, phthalocyanine (abbreviation: H2Pc) and copper phthalocyanine (abbreviation: Cu Phthalocyanine compounds such as 4,4'-bis[N-(4-diphenylamino)phthalocyanine phenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4- [bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1' -biphenyl)-4,4'-diamine (abbreviation: DNTPD), or other aromatic amine compounds, or poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviation The hole injection layer 114 can also be formed from a polymer such as PEDOT / PSS. do.

[0178] In addition, the hole-injecting layer 114 may be formed by adding an acceptor substance to a hole-transporting substance. A composite material can be used. Note that a hole transporting material may contain an acceptor material. By using a material that has been developed, it is possible to select a material for forming the electrode regardless of the work function of the electrode. In other words, the first electrode 102 can be made of not only a material with a large work function, but also a material with a low work function. Small materials can also be used. Acceptor materials include 7,7,8 ,8-Tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TC NQ), chloranil, etc. Also included are transition metal oxides. Further, oxides of metals belonging to groups 4 to 8 of the periodic table can be mentioned. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, Dendrimer, tungsten oxide, manganese oxide, and rhenium oxide are preferred due to their high electron-accepting properties. In particular, molybdenum oxide is stable in the air, has low hygroscopicity, and is easy to handle. preferable.

[0179] The hole transporting substances used in the composite materials include aromatic amine compounds and carbazole derivatives. Various types of compounds, such as aromatic hydrocarbons, polymers (oligomers, dendrimers, polymers, etc.) Various organic compounds can be used. It is preferable that the organic compound has a high hole transporting property. -6 cm 2 / Vs or later In the following, the hole transport in the composite material is preferably a material having a hole mobility of 100 nm or higher. Specific examples of organic compounds that can be used as the transport material are listed below.

[0180] For example, the aromatic amine compound is N,N'-di(p-tolyl)-N,N'-diphenyl Phenyl-p-phenylenediamine (DTDPPA), 4,4'-bis[N-(4- Diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N ,N'-Bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl 1,3-Diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD) ,5-Tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) and the like.

[0181] Specific examples of carbazole derivatives that can be used in composite materials include 3-[N- (9-Phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazol 3,6-bis[N-(9-phenylcarbazole-3 -yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2) , 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino] -9-phenylcarbazole (abbreviation: PCzPCN1), etc.

[0182] Other carbazole derivatives that can be used in composite materials include 4,4'- Di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N- Carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl- 9-Anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[ 4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. There can be.

[0183] In addition, examples of aromatic hydrocarbons that can be used in the composite material include 2-tert -Butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2- tert-Butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3, 5-Diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9 ,10-Bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,1 0-Di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene 2-tert-butylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAn th), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA) , 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7- Tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl 9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,1 0'-Diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl) 10,10'-bis[(2,3,4,5,6-pentafluorophenyl) phenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. -6 cm 2 / Vs or more, and uses aromatic hydrocarbons with carbon numbers of 14 to 42. It is more preferable to do so.

[0184] The aromatic hydrocarbon that can be used in the composite material may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2- Diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2- diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like.

[0185] In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltriphenylphosphine) nylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenyl Amino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide]( abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis Polymer compounds such as Poly(phenyl)benzidine (abbreviation: Poly-TPD) can also be used. can.

[0186] By forming a hole injection layer, the hole injection property is improved, and the emission voltage is small. It is possible to obtain an optical element.

[0187] The hole transport layer 115 is a layer containing a substance having a hole transport property. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1, 1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4''-tris (N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4 ''-Tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(spiro-9,9'-bifluorene-2 -yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'- (9-Phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), etc. The aromatic amine compounds described here have high hole transport properties and , mainly 10 -6 cm 2 The composite material described above has a hole mobility of 100 / Vs or more. The organic compounds listed as hole transporting materials in the material can also be used for the hole transport layer 115. In addition, poly(N-vinylcarbazole) (abbreviation: PVK) and poly(4-vinyltetradecane) Polymer compounds such as polyphenylene sulfide (PVTPA) can also be used. The layer containing the hole transporting substance may be a single layer or may be a layer having two or more layers made of the above substance. It may also be a laminate.

[0188] The electron transport layer 117 is a layer containing a substance having an electron transport property. As the material, the material having the electron transporting property that can be used as the host material can be used. A material having an anthracene skeleton or a material having an anthracene skeleton can be used.

[0189] In addition, a layer for controlling the movement of electron carriers may be provided between the electron transport layer and the light emitting layer. This is achieved by adding a small amount of a substance with high electron trapping properties to a material with high electron transport properties as described above. A layer that adjusts the carrier balance by suppressing the movement of electron carriers. This type of structure prevents light from being emitted by electrons passing through the light-emitting layer. This is highly effective in suppressing problems that arise (such as a decrease in element life).

[0190] In addition, an electron transport layer 117 is provided between the electron transport layer 117 and the second electrode 104. An electron injection layer 118 may be provided. The electron injection layer 118 may be formed of lithium fluoride (LiF), Alkali metals such as cesium fluoride (CsF), calcium fluoride (CaF2), etc. Alkaline earth metals or compounds thereof can be used. For example, The layer is made of a material containing an alkali metal or an alkaline earth metal or a compound thereof. Alternatively, the electron injection layer 118 may be made of an electride. For example, an electride is a mixture of calcium and aluminum oxide with high electron density. The electron-injecting layer 118 may be a material having an electron-transporting property. By using a material containing an alkali metal or an alkaline earth metal in the layer made of the material, This is more preferable because electron injection from the second electrode 104 can be performed efficiently.

[0191] The material for forming the second electrode 104 is a material having a small work function (specifically, 3.8 eV Metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Examples of such cathode materials include lithium (Li) and cesium (Cs). Potash metal, as well as magnesium (Mg), calcium (Ca), and strontium (Sr) Elements belonging to Group 1 or 2 of the Periodic Table, such as Mg, Ag, etc., and alloys containing these elements (e.g., , AlLi), europium (Eu), ytterbium (Yb), and other rare earth metals However, the second electrode 104 and the electron transport layer may be formed of a material other than the above-mentioned material. By providing an electron injection layer, the material can be made of Al, Ag, ITO, and ketone regardless of the magnitude of the work function. Various conductive materials such as indium oxide-tin oxide containing silicon oxide or indium tin oxide are used as the second These conductive materials can be used as the electrode 104. The film can be formed by using a jet method, a spin coating method, or the like.

[0192] The EL layer 103 (or the EL layers 103d and 103a) may be formed by a dry process. Various methods can be used, including wet methods. For example, vacuum deposition, ink jet deposition, etc. Alternatively, a different composition may be used for each electrode or layer. It may also be formed by a film method.

[0193] The electrodes may be formed by a wet method using the sol-gel method, or by a paste of a metal material. Alternatively, the insulating layer 12 may be formed by a dry method such as a sputtering method or a vacuum deposition method. It may be formed using.

[0194] The light emission of the light emitting element is caused by either the first electrode 102 or the second electrode 104. Therefore, the electric current is taken out through the first electrode 102 or the second electrode 104. Either one or both of the electrodes is formed of a light-transmitting electrode.

[0195] <About tandem elements> Next, a light-emitting device having a structure in which multiple light-emitting units are stacked (hereinafter referred to as a tandem-type light-emitting device) was The embodiment of the light-emitting element (also referred to as a "light-emitting element") will be described with reference to FIG. 5(A). A light-emitting device having a plurality of light-emitting units between a pair of electrodes composed of a first electrode 102 and a second electrode 104. One light-emitting unit is a light-emitting element having the same structure as the EL layer 103a shown in FIG. That is, the light-emitting element shown in FIG. 5C has one light-emitting unit. The light-emitting element shown in FIG. 5A is a light-emitting element having a plurality of light-emitting units. It can be said.

[0196] In FIG. 5A, a first light-emitting unit 103b, an intermediate layer 109 which is a charge generating layer, and a second light emitting unit 103c. The EL layer 103 is formed by laminating the first light-emitting unit 103b and the second light-emitting unit 103c. One of the light emitting units 103c is a unit that emits blue fluorescence, and the other is a unit that emits green or The unit emits yellow phosphorescence. The EL layer 103 emits blue fluorescence and green phosphorescence or The resulting light emission is a combination of blue fluorescence and yellow phosphorescence.

[0197] In the tandem element, light-emitting units corresponding to the EL layer 103a are arranged in series with an intermediate layer 109 sandwiched therebetween. Therefore, the fluorescent light-emitting layer and the phosphorescent light-emitting layer are separated from each other. It is possible to easily achieve both fluorescent emission and phosphorescent emission in one light-emitting device. can be done.

[0198] The intermediate layer 109 contains a composite material of an organic compound and a metal oxide. The composite material of the metal oxide and the metal oxide can be used for the hole injection layer 114. Composite materials of organic compounds and metal oxides have the properties of carrier injection and carrier transport. Since it has excellent characteristics, it can be driven at low voltage and low current. When the anode side of the EL element is in contact with the intermediate layer, the intermediate layer acts as a hole injection layer for the emitting unit. Since the light-emitting unit also serves as a hole-injection layer, the light-emitting unit does not need to be provided with a hole-injection layer.

[0199] The intermediate layer 109 is made by combining a layer containing the above composite material with a layer made of other materials. For example, a layer including a composite material and an electron donor material may be formed as a laminate structure. and a layer containing a compound having high electron transport properties. Alternatively, the insulating layer may be formed by a layer including a composite material of an organic compound and a metal oxide, and a transparent conductive film. The insulating layer 11 may be formed by laminating the above.

[0200] In addition, an electron injection buffer is provided between the intermediate layer 109 and the light-emitting unit on the anode side of the intermediate layer. The electron injection buffer layer is a very thin film of an alkali metal and an electron transporting layer. The thin layer of alkali metal is a layer containing electron relay material. The electron relay layer corresponds to layer 118 and has the function of reducing the barrier for electron injection. It prevents interactions between the metal film and the intermediate layer, and has the function of smoothly transferring electrons. The LUMO level of the electron transporting material in the intermediate layer 109 is The LUMO level of the acceptor material and the electron injection barrier in the light-emitting unit on the anode side are The LUMO level of the material contained in the layer adjacent to the buffer layer is between the two layers. The numerical values ​​of the energy levels of the electron-transporting material in the electron-relay layer are The energy level is set to -5.0 eV or more, and preferably to -5.0 eV or more and -3.0 eV or less. The electron-transporting substance contained in the electron relay layer is a phthalocyanine-based material or a gold material. It is preferred to use metal complexes having metal-oxygen bonds and aromatic ligands. The alkali metal film of the injection buffer layer plays the role of an electron injection layer in the light-emitting unit on the anode side. Therefore, there is no need to form an electron injection layer over the light-emitting unit.

[0201] In any case, the light emitting unit 103b is sandwiched between the first light emitting unit 103b and the second light emitting unit 103c. When a voltage is applied between the first electrode 102 and the second electrode 104, the intermediate layer 109 It is sufficient that the light-emitting unit injects electrons into the light-emitting unit and the light-emitting unit injects holes into the other light-emitting unit. .

[0202] <Fluorescent / phosphorescent single elements> Next, a fluorescent light emitting device having both a fluorescent light emitting layer and a phosphorescent light emitting layer in one light emitting unit was fabricated. The phosphorescent single element will be described with reference to FIG. 5(B). The light-emitting element shown in FIG. The EL layer 103d includes two light-emitting layers (a first light-emitting layer 116d-1 and a second light-emitting layer 116d-2). -2) are installed in close proximity to each other.

[0203] Either the first light-emitting layer 116d-1 or the second light-emitting layer 116d-2 emits blue fluorescent light. The other emits green or yellow phosphorescence. Blue fluorescence and green phosphorescence combined, or blue fluorescence and yellow phosphorescence combined A clear light emission is obtained.

[0204] Of the first light-emitting layer 116d-1 and the second light-emitting layer 116d-2, which is a phosphorescent light-emitting layer the layer includes a first organic compound, a second organic compound, and a phosphorescent material; The first organic compound and the second organic compound form an exciplex, and phosphorescence is emitted from the exciplex. It is preferable that the energy transfer to the light-emitting substance is performed. By this, even if the fluorescent emitting layer and the phosphorescent emitting layer are formed close to each other, phosphorescence is not quenched. Therefore, fluorescence and phosphorescence can be obtained simultaneously and efficiently without any trouble.

[0205] Usually, when a fluorescent layer and a phosphorescent layer are introduced into the same EL layer, phosphorescence is produced. The triplet excitation energy of the layer is transferred to the host material that occupies most of the fluorescent layer, This causes a significant decrease in luminous efficiency. This is because the fluorescent layer usually contains a host material Condensed aromatic rings (especially condensed aromatic hydrocarbon rings) such as anthracene, which have low triplet levels ) skeleton is used, the triplet excitation energy generated in the phosphorescent layer is This is because the phosphorus migrates to the host material of the fluorescent-emitting layer and is deactivated without any radiation. In the optical layer, the desired emission wavelength and good device characteristics can be obtained without using a substance with a condensed aromatic ring structure. Because it is difficult to obtain reliability, the fluorescent and phosphorescent layers are integrated into the same EL layer. With such a structure, it is difficult to obtain a light emitting element having good characteristics.

[0206] In addition, the triplet excited state has a long relaxation time, so the diffusion distance of excitons is long, and phosphorescence is emitted. Many of the excitons generated inside the layer also diffuse into the fluorescent layer, resulting in non-radiative emission. The loss of activity is making the situation more serious.

[0207] In the phosphorescent layer, the first organic compound and the second organic compound form an exciplex. The triplet excitation energy is transferred from this exciplex to the phosphorescent material, resulting in light emission. This configuration can solve the above problem.

[0208] An exciplex is an excited state consisting of two substances. It emits light. When the excited complex reaches the ground state, the two substances that formed it vibrate again as separate substances. In other words, there is no ground state in an exciplex, and this is why the energy between the exciplexes is In principle, energy transfer and energy transfer from other substances to exciplexes are difficult to occur.

[0209] Most of the excitons in the phosphorescent layer exist as exciplexes. The singlet excitation energy of the organic compound is the same as that of the first organic compound and the second organic compound. Furthermore, the triplet excitation energy of the exciplex is smaller than the first excitation energy. The first organic compound and the second organic compound are arranged so that the first organic compound and the second organic compound are smaller than the second organic compound. By selecting the organic compound, the exciplex can be converted to the first organic compound and the second organic compound. As mentioned above, the energy transfer of the excited complex can be prevented. There is almost no energy transfer between the two bodies, so almost all of the excitation energy of the exciplex is is transferred to the phosphorescent material and converted into light. As a result, both fluorescence and phosphorescence can be achieved. can.

[0210] Here, when the fluorescent light-emitting layer and the phosphorescent light-emitting layer are formed in contact with each other, The energy transfer from the exciplex to the host material of the fluorescent layer (especially the triplet energy transfer) However, as mentioned above, there is almost no diffusion of excitons in the phosphorescent layer. Therefore, the range in which energy transfer from the exciplex to the host material of the fluorescent-emitting layer occurs The excitation energy remains in a very local area (i.e., at the interface between the fluorescent and phosphorescent layers) and Therefore, the fluorescent and phosphorescent layers do not necessarily have to be separated. It is not necessary for the two to be in contact with each other, but even if they are in contact, they can emit fluorescent and phosphorescent light with high efficiency. In addition, the thickness of the layer between the fluorescent and phosphorescent emitting layers is more than 0 nm and the thickness is 20 nm. By providing a separation layer, the fluorescent-emitting layer can be separated from the light-emitting layer by a thickness of 1 nm or less. It is also possible to suppress the transfer of excitation energy at the interface with the phosphorescent layer, resulting in higher efficiency. The thickness of the separation layer is preferably 1 nm or more and 10 nm or less. The separation layer is composed of the first organic compound and the second organic compound in the phosphorescent layer. This is a preferred configuration since it has a higher effect of suppressing the transfer of excitation energy.

[0211] Materials Constituting the Light-Emitting Layer 116, the First Light-Emitting Layer 116d-1, and the Second Light-Emitting Layer 116d-2 The following explains this.

[0212] The fluorescent substance is N,N'-bis[4-(9H-carbazol-9-yl)phenyl] Nyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl) Triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4' -(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPP A), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl] -9H-Carbazole-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9- Anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl PCBAPA, 4-[4-(10-phenyl-9-anthryl)phenyl ]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation : PCBAPBA), Perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl] )phenyl]-N,N'-diphenyl-pyrene-1,6-diamine (abbreviation: 1,6FLP APrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl 1,6-diamine (abbreviation: 1 ,6mMemFLPAPrn) and other blue emitting dyes (emission wavelength 400nm to 480nm) In particular, 1,6FLPAPrn and 1,6mMemFLPAPrn Condensed aromatic diamine compounds, such as pyrene diamine compounds, have hole-trapping properties. This is preferred because it has high light-emitting properties, excellent luminous efficiency and reliability.

[0213] Examples of materials that can be used as phosphorescent materials include the following: Can be obtained.

[0214] The compound that mainly exhibits green phosphorescence is tris(4-methyl-6-phenylpyridine). midinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t- Butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBupp m)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)i Ir(mppm)2(acac) Nato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6 -(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [ Organometallic iridium derivatives with pyrimidine skeletons such as Ir(nbppm)2(acac)] complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium (III) (abbreviation Name: [Ir(ppy)3]), Bis(2-phenylpyridinato-N,C 2’ )iridium (III) Acetylacetonate (abbreviation: [Ir(ppy)2(acac)]) In addition to organometallic iridium complexes with pyridine skeletons, tris(acetylacetonato)(mono Nophenanthroline) terbium(III) (abbreviation: [Tb(acac)3(Phen) ]) are examples of rare earth metal complexes. Dium complexes are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0215] The compound that mainly exhibits yellow phosphorescence is (acetylacetonato)bis[5-methyl Ru-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III)( Abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis{4,6- Dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl nyl-κC}iridium(III) (abbreviation: Ir(dmppm-dmp)2(acac) ), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(II I) (abbreviation: Ir(dppm)2(acac)) iridium complexes of the acetylacetonato group and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyridinium complexes radinato)iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), ( Acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate) Pyrazolium, such as iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes with diphenyl ether skeletons and tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: Ir(pq)2(a cac)), bis(benzo[h]quinolinato)iridium(III) acetylacetoner Ir(bzq)2(acac)), bis{2-[4'-(perfluorophenyl (phenyl)pyridinato-N,C 2’}Iridium(III) acetylacetonate ( Abbreviation: Organometallic compounds with a pyridine skeleton, such as Ir(p-PF-ph)2(acac) In addition to iridium complexes, bis(2-phenylbenzothiazolato-N,C 2’ )iridium( III) Acetylacetonate (abbreviation: Ir(bt)2(acac)) In addition, organometallic iridium complexes with pyrimidine skeletons are also outstanding in terms of reliability and luminescence efficiency. This is particularly preferred because it has excellent properties.

[0216] The host material can be a material having various carriers such as a material having an electron transport property or a material having a hole transport property. The host material of the phosphorescent emitting layer is a first organic compound and a second organic compound. It is preferable that the first organic compound and the second organic compound are two kinds of substances. It is preferable that the organic compounds are a combination that forms an exciplex. One of the compound and the second organic compound is a material having an electron transporting property, and the other is a material having a hole transporting property. A material having a light-transmitting property is preferred because it is advantageous in forming an exciplex. be.

[0217] In addition, the exciplex has the lowest energy absorption band of a fluorescent substance or a phosphorescent substance. Select a combination that forms an exciplex that emits light with a wavelength that overlaps with the wavelength of This allows for smooth energy transfer and efficient light emission. This is a preferable configuration because the voltage also decreases.

[0218] Examples of materials having electron transport properties include bis(10-hydroxybenzo[h]quinoline). Beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinola Bis(8-phenylphenolato)aluminum(III) (abbreviation: BAlq) -quinolinolato)zinc(II)(abbreviation: Znq), bis[2-(2-benzoxazolyl )phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl )phenolato]zinc(II) (abbreviation: ZnBTZ) and other metal complexes, (4-tert-butylphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation Name: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butyl phenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(pt ert-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), 2,2',2''-(1,3, 5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: T PBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1 H-benzimidazole (abbreviation: mDBTBIm-II) and other polyazole skeletons Heterocyclic compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[ f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothio [4-phenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl 2mCzBPDBq, 4, 6-Bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mP nP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation Heterocyclic compounds with diazine skeletons such as 4,6mDBTP2Pm-II, 3, 5-Bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DC zPPy), 1,3,5-tri[3-(3-pyridyl)-phenyl]benzene (abbreviation: T mPyPB) and other heterocyclic compounds having a pyridine skeleton. Heterocyclic compounds having a diazine skeleton and a pyridine skeleton have good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton are preferred. has a high electron transporting property and contributes to reducing the driving voltage.

[0219] As a material having hole transport properties, 4,4'-bis[N-(1-naphthyl)-N-phenylene N,N'-bis(3-methylphenyl)-N ,N'-Diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD) , 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenyl amino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene 4-phenyl-3'-(9-yl)triphenylamine (abbreviation: BPAFLP), -phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4- Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9-H- Carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1- naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)-triphenyl PCBANB, 4,4'-di(1-naphthyl)-4''-(9-phenyl -9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9 -Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl] )phenyl]-fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4 -(9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'-bi Compounds with an aromatic amine skeleton, such as fluorene-2-amine (PCBASF) 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N- Carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl) 3,3'-bis(9-phenyl- 9H-carbazole (abbreviation: PCCP) and other compounds with a carbazole skeleton, ,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)(abbreviation Name: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-ful oren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4 -[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzyl Compounds with a thiophene skeleton, such as dibenzothiophene (abbreviation: DBTFLP-IV), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation :DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl )phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) Among the above, compounds having an aromatic amine skeleton are preferred. Compounds having a carbazole skeleton have good reliability and high hole transport properties. This is also preferable because it contributes to reducing the driving voltage. Among the substances, a hole transport material may be used.

[0220] The host material may be a mixture of a plurality of substances. When using a material having electron transport properties, a material having hole transport properties is mixed. It is preferable to mix a material having an electron transporting property with a material having a hole transporting property. This enhances the transport properties of the light-emitting layer 116, the first light-emitting layer 116d-1, and the second light-emitting layer 116d-2. The recombination region can be easily controlled. The ratio of the content of the material having hole transport properties to the content of the material having electron transport properties is: material having hole transport properties:electron transport properties The ratio of the material having the desired properties to the material having the desired properties may be 1:9 to 9:1.

[0221] The host material for the fluorescent-emitting layer is 9-phenyl-3-[4-(10-phenyl-9- anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1- naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9- [4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation : CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzyl Benzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl (2-phenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation :2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluorene -9-yl)-biphenyl-4'-yl}-anthracene (abbreviation: FLPPA) and other anthracenes A material having an anthracene skeleton is particularly suitable. When used as a material, it is possible to realize a light-emitting layer having good luminous efficiency and durability. In addition, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA have very good properties. This is the preferred choice because it shows

[0222] The light-emitting layer 116, the first light-emitting layer 116d-1, and the second light-emitting layer 116d-2 each having the above-mentioned configuration are 16d-2 is a method for co-evaporation in a vacuum deposition method, or for deposition by inkjet or spin coating as a mixed solution. The insulating layer can be prepared by a deposition method, a dip coating method, or the like.

[0223] <Micro-optical resonator (microcavity) structure> The light-emitting device having a microcavity structure has the pair of electrodes as a reflective electrode and a semi-transmissive electrode. The reflective electrode and the semi-transmissive / semi-reflective electrode are constructed as described above. These correspond to the first electrode and the second electrode. At least one electrode is provided between the reflective electrode and the semi-transmissive / semi-reflective electrode. The device also has an EL layer, and has at least a light-emitting layer that serves as a light-emitting region.

[0224] In addition, this configuration is used in a light emitting device using blue fluorescence and yellow phosphorescence to obtain green light emission. It can be used particularly effectively.

[0225] In a light-emitting device using blue fluorescence and yellow phosphorescence, which is one embodiment of the present invention, green light is obtained. To achieve this, the blue fluorescence must be converted to green light by a color conversion layer. If the color filter is used, the purity of the green color may decrease. Although it is possible to cut off the light, it is also possible to use a resonant structure to amplify the blue light emission and attenuate the yellow light emission. This is a preferable configuration since the energy loss is relatively small.

[0226] The light emitted in all directions from the light-emitting layer in the EL layer is reflected by the reflective electrode and the semi-transmissive / semi-reflective The reflector is made of a conductive material with reflectivity. The reflectance of the film to visible light is 40% to 100%, preferably 70% to 1 00% and its resistivity is 1×10 -2 The membrane is assumed to be less than Ωcm. The over- or semi-reflective electrode is made of a conductive material that is reflective and light-transmitting. The reflectance of visible light to the outside world is 20% to 80%, preferably 40% to 70%, and has a resistivity of 1×10 -2 It is assumed that the film has a resistance of less than Ωcm.

[0227] In addition, the light-emitting element has a thickness of the transparent conductive film, the composite material, the carrier transport material, etc. By changing the optical distance between the reflective electrode and the semi-transmissive and semi-reflective electrode, Between the reflective electrode and the semi-transmissive / semi-reflective electrode, the light of the resonating wavelength is strengthened and the light of the non-resonating wavelength is strengthened. It is possible to attenuate light of wavelengths.

[0228] Of the emitted light, the light reflected by the reflective electrode and returned (first reflected light) is This causes significant interference with the light (first incident light) that is directly incident on the semi-transmissive / semi-reflective electrode from the optical layer. Therefore, the optical distance between the reflective electrode and the light-emitting layer is set to (2n-1)λ / 4 (where n is a natural number greater than or equal to 1). It is preferable to adjust the optical path to the wavelength of the light to be amplified. This causes the phases of the first reflected light and the first incident light to be aligned, thereby amplifying the light emitted from the light-emitting layer. It is possible to do so.

[0229] In the above configuration, even if the EL layer has a plurality of light-emitting layers, a single light-emitting For example, the above-mentioned tandem type light emitting device may be combined with the above-mentioned structure. In addition, a single light-emitting element is provided with multiple EL layers sandwiching a charge generating layer, and each EL layer is provided with a single The present invention may be applied to a configuration in which several or a plurality of light emitting layers are formed.

[0230] By having a microcavity structure, the emission intensity of a specific wavelength in the forward direction can be enhanced. This allows for lower power consumption. The light-emitting element using a phenylamino)pyrene derivative as a luminescent center substance emits light from the derivative. The emission spectrum has a narrow half-width and a sharp spectral shape, The use of a cavity structure has a large light emission amplification effect, resulting in extremely good light emission efficiency. A light emitting element having such a property can be obtained.

[0231] <Light-emitting device> A light-emitting device according to one embodiment of the present invention will be described with reference to FIG. FIG. 6(B) is a cross-sectional view taken along lines AB and CD in FIG. 6(A). This light emitting device includes a driving circuit section, indicated by a dotted line, which controls the light emission of the light emitting elements. (source line driving circuit) 601, pixel section 602, driving circuit section (gate line driving circuit) 603 Also, 604 is a sealing substrate, 605 is a sealing material, and the sealing material 605 surrounds the The inside of the hole is a space 607.

[0232] The lead wiring 608 is connected to the source line driver circuit 601 and the gate line driver circuit 603. The wiring is for transmitting the input signal, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal from Lint Circuit 609 Although only the FPC is shown here, the FPC has a printed circuit board. A printed wiring board (PWB) may be attached. This includes not only the device itself, but also the state in which an FPC or PWB is attached to it. do.

[0233] Next, the cross-sectional structure will be described with reference to FIG. A source line driver circuit 601, which is a driver circuit section, and a pixel section are formed in this example. 6, one pixel in the pixel section 602 is shown.

[0234] The source line driver circuit 601 includes an n-channel FET 623 and a p-channel FET 62 4 is combined to form a CMOS circuit. The driving circuit is also a variety of CMOS circuits. Alternatively, the substrate may be a PMOS circuit or an NMOS circuit. Although the driver integrated type with the drive circuit is shown above, this is not necessarily required. It may also be formed externally rather than on the substrate.

[0235] The pixel section 602 includes a switching FET 611, a current control FET 612, and The pixel is formed of a plurality of pixels including a first electrode 613 electrically connected to the drain. However, the present invention is not limited to this, and a pixel unit may be formed by combining three or more FETs and a capacitance element. Good too.

[0236] The type and crystallinity of the semiconductor used in the FET are not particularly limited, and an amorphous semiconductor is used. Examples of semiconductors used in FETs include the first Group 3 (gallium, etc.) semiconductors, Group 14 (silicon, etc.) semiconductors, compound semiconductors, oxide semiconductors In this case, an organic semiconductor material can be used, and it is particularly preferable to use an oxide semiconductor. Examples of oxide semiconductors include In-Ga oxide and In-M-Zn oxide (where M is Al). , Ga, Y, Zr, La, Ce, or Nd). The oxide semiconductor has a voltage of 2 eV or more, preferably 2.5 eV or more, and more preferably 3 eV or more. By using such a material, the off-state current of the transistor can be reduced, and therefore it is preferable to use such a material. It is a composition.

[0237] An insulator 614 is formed to cover the end of the first electrode 613. It can be formed by using a di-type photosensitive acrylic resin film.

[0238] In order to improve the covering property, the upper end or the lower end of the insulator 614 is provided with a curvature. For example, the material of the insulator 614 is a positive photosensitive adhesive. When using krill, the radius of curvature (0.2 μm to 3 μm) is set only on the upper end of the insulator 614. It is preferable to provide a curved surface having a curved surface. Alternatively, a positive-type photosensitive resin may be used.

[0239] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. These correspond to the first electrode 102 and the EL layer 103 described in FIGS. 5(A) to 5(C), respectively. (or the EL layer 103 d or the EL layer 103 a ) and the second electrode 104 .

[0240] Furthermore, the sealing substrate 604 is bonded to the element substrate 610 with a sealant 605. A space 607 surrounded by an element substrate 610, a sealing substrate 604, and a sealant 605 contains light-emitting elements. The space 607 is filled with a filler. In addition to being filled with an inert gas (nitrogen, argon, etc.), it is also possible to fill it with a sealing material 605. If a recess is formed in the sealing substrate and a desiccant 625 is provided there, the sealing substrate can be protected from the effects of moisture. This is a preferable configuration because it is possible to suppress deterioration due to the above-mentioned causes.

[0241] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials are as impermeable to moisture and oxygen as possible. Materials used for the substrate 610 and the sealing substrate 604 include glass substrates, quartz substrates, and FRP ( Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride) For example, a plastic substrate made of polyester, acrylic or the like can be used.

[0242] For example, in this specification, a transistor or a light-emitting element is formed using various substrates. The type of the substrate is not limited to a specific one. Examples of the substrate include semiconductor substrates (e.g., single crystal substrates or silicon substrates), SOI substrates, glass substrates, Quartz substrate, plastic substrate, metal substrate, stainless steel substrate, stainless steel Substrate with foil, tungsten substrate, substrate with tungsten foil, flexible These include substrates, laminated films, papers containing fibrous materials, or base films. Examples of the glass substrate include barium borosilicate glass, aluminoborosilicate glass, or silicon. Lime glass, etc. Flexible substrates, laminated films, base films, etc. Examples include: Polyethylene terephthalate (PET) , polyethylene naphthalate (PEN), and polyethersulfone (PES). For example, there is a plastic material such as acrylic. Examples of the material include polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. Also available are polyamide, polyimide, aramid, epoxy, inorganic deposition film, etc. In particular, semiconductor substrates, single crystal substrates, SOI substrates, etc. By manufacturing transistors using this method, there is less variation in characteristics, size, shape, etc. This allows the manufacture of transistors that are small in size and have high current capability. When a circuit is constructed using transistors, the power consumption of the circuit can be reduced and the circuit can be highly integrated. It is possible.

[0243] In addition, a flexible substrate is used as the substrate, and transistors and light-emitting elements are directly formed on the flexible substrate. Alternatively, a peeling layer may be formed between the substrate and the transistor or between the substrate and the light-emitting element. The release layer may be provided to separate the semiconductor device from the substrate after a part or whole of the semiconductor device is completed thereon. The transistor can be separated and transferred to another substrate. The above-mentioned release layer can be transferred to a substrate having poor mechanical properties or a flexible substrate. The laminated structure of inorganic films such as stainless steel and silicon oxide films, and the organic film such as polyimide on the substrate A configuration in which a resin film is formed, etc., can be used.

[0244] That is, a transistor or a light-emitting element is formed on a certain substrate, and then the transistor or light-emitting element is formed on another substrate. The transistors and light-emitting elements may be transposed and disposed on another substrate. An example of a substrate on which a transistor or a light-emitting element is transferred is a substrate on which the above-mentioned transistor is formed. In addition to the substrates that can be used, paper substrates, cellophane substrates, aramid film substrates, polyimide substrates, Midofilm substrate, stone substrate, wood substrate, fabric substrate (natural fibers (silk, cotton, hemp), synthetic fibers ( Nylon, polyurethane, polyester) or regenerated fiber (acetate, cupra, These include polyester, recycled polyester, leather substrates, and rubber substrates. By using this substrate, it is possible to form transistors with good characteristics and low power consumption. It is possible to form a sintered material, manufacture a device that is durable, heat resistant, lightweight, or thin. Cut.

[0245] 7A and 7B show an example of a light-emitting device according to the present embodiment. In FIG. 7A, a substrate 1001, an insulating base film 1002, gate insulating film 1003, gate electrodes 1006, 1007, 1008, the first An interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driving The driving circuit section 1041, the first electrodes 1024Y, 1024R, 1024G, 102 4B, a partition wall 1025, an EL layer 1028, a second electrode 1029 of the light-emitting element, and a sealing substrate 103 1, sealing material 1032, etc. are shown. The EL layer is a composite of blue fluorescence and green phosphorescence. The assumption is that the light emitted is a combination of blue fluorescent light and yellow phosphorescent light, but Not limited.

[0246] In FIG. 7A, red color conversion layer 1034R, green color conversion layer 1034G, blue color conversion layer 1034R, Color filter layer 1034B, yellow color conversion layer (in the case of blue fluorescent and green phosphorescent) or yellow color The color filter layer (for blue fluorescence and yellow phosphorescence) 1034Y is provided on a transparent substrate 1033. A black layer (black matrix) 1035 may be further provided. The transparent substrate 1033 on which the filter layer, the color conversion layer and the black layer are provided is aligned and The color filter layer, the color conversion layer, and the black layer are fixed at 1001. It may be covered with layer 1036 .

[0247] In FIG. 7B, the color filter layer and the color conversion layer are formed by a gate insulating film 1003 and a first interlayer insulating film. In this example, the color filter layer and the color conversion layer are formed between the insulating film 1020 and the color filter layer 1020. may be provided between the substrate 1001 and the sealing substrate 1031.

[0248] In the light emitting device described above, light is taken in toward the substrate 1001 on which the FET is formed. The light emitting device has a bottom emission structure, but the light is emitted from the sealing substrate 1031 side. The light emitting device may have a structure in which the light is extracted (top emission type). Top emission type A cross-sectional view of the light-emitting device is shown in FIG. 8. In this case, a substrate 1001 that does not transmit light is used. Until the connection electrode that connects the FET and the anode of the light-emitting element is fabricated, The third interlayer insulating film 1037 is then formed in the same manner as in the case of an emission type light emitting device. The insulating film may be formed to cover the first interlayer 1022. The insulating film may also serve as a flattening film. The insulating film 1037 is formed using various materials, including the same material as the second interlayer insulating film. It is possible.

[0249] The first electrodes 1024Y, 1024R, 1024G, and 1024B of the light-emitting element are positive electrodes. The electrode is generally a top electrode, but it can also be a cathode. In the case of a device, it is preferable that the first electrode is a reflective electrode. 5A to 5C, the EL layer 103, the EL layer 103d, and the EL layer 103a. The device has such a configuration and has an element structure that can emit white light.

[0250] In the top emission structure shown in Figure 8, a color conversion layer and a color filter layer are provided to seal the Sealing can be performed with a substrate 1031. The sealing substrate 1031 has a structure in which a pixel is disposed between pixels. A black layer (black matrix) 1035 may be provided so as to color the color filter layer. The color conversion layer and the black layer (black matrix) are covered with an overcoat layer 1036. Note that the sealing substrate 1031 is a light-transmitting substrate.

[0251] In addition, although an example of full-color display using four colors, red, green, blue, and yellow, is shown here, the present invention is not limited to this. Alternatively, full color display may be performed using three colors, red, green, and blue, or four colors, red, green, blue, and white.

[0252] FIG. 9 shows a passive matrix light-emitting device according to one embodiment of the present invention. FIG. 9(A) is a diagram showing a light emitting device, and FIG. 9(B) is a cross-sectional view taken along the line XY of FIG. 9(A). In FIG. 9, an EL layer 955 is provided between an electrode 952 and an electrode 956 on a substrate 951. The end of the electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided on the upper surface. The sidewall of the partition layer 954 becomes thinner as it approaches the substrate surface. The side walls are inclined so that the distance between them becomes narrower. The cross section of the wall layer 954 in the short side direction is trapezoidal, and the base (which is in the same direction as the surface direction of the insulating layer 953) The side that faces the insulating layer 953 is the upper side (the side that faces the insulating layer 953). The side of the partition wall layer 954 is shorter than the side of the partition wall layer 954 that is not in contact with the insulating layer 953. Therefore, defects in the light emitting element due to static electricity or the like can be prevented.

[0253] The light emitting device described above has a large number of minute light emitting elements arranged in a matrix, which are called pixels. Since each of the FETs formed in the display can be controlled, This light emitting device can be suitably used as a device.

[0254] ≪Electronic equipment≫ An example of an electronic device according to one embodiment of the present invention will be described. video equipment (also called television or television receiver), computers, etc. Digital cameras, digital video cameras, digital photo frames, mobile phones ( Mobile phones, also called mobile phone devices, portable game machines, portable information terminals, audio playback devices, Examples of electronic devices include large game machines such as dick machines. Specific examples of these electronic devices are shown below. .

[0255] FIG. 10A shows an example of a television device. The television device has a housing 7. A display unit 7103 is built into the display unit 101. Also, in this embodiment, a stand 7105 is used. The display unit 7103 displays images. The display portion 7103 has light-emitting elements arranged in a matrix.

[0256] The television device can be operated using an operation switch provided on the housing 7101 or a separate remote control. The remote control 7110 includes an operation key 710 9, the channel and volume can be controlled, and the image displayed on the display unit 7103 can be In addition, the remote control operation device 7110 can operate the remote control operation device 711. A display portion 7107 for displaying data output from the input device may be provided.

[0257] The television device is assumed to be equipped with a receiver, a modem, etc. It can receive general television broadcasts and can also transmit wired or wirelessly via a modem. By connecting to a communications network, it can be one-way (sender to receiver) or two-way (transmit It is also possible to communicate information between a sender and a recipient, or between recipients themselves.

[0258] FIG. 10B1 shows a computer, which includes a main body 7201, a housing 7202, and a display unit 7203. , a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. In addition, this computer includes a display unit 7203 having light emitting elements arranged in a matrix. The computer shown in FIG. 10(B1) is constructed by using the The computer in FIG. 10B2 has a keyboard 7204, a pointing device, A second display unit 7210 is provided instead of the display device 7206. The second display unit 7210 is a touch panel type, and the input Input can be made by operating the display with a finger or a special pen. The display unit 7210 can display not only input images but also other images. The display unit 7203 may also be a touch panel. The two screens are connected by a hinge. This can lead to problems such as scratches or damage to the screen during storage or transportation. It can be prevented.

[0259] 10C and 10D show an example of a portable information terminal. The portable information terminal has a housing 74. In addition to the display unit 7402 incorporated in the 01, the operation buttons 7403 and the external connection port 7404 7405, a microphone 7406, and the like. The display unit 7402 has a display portion 7402 in which the display devices are arranged in a matrix.

[0260] In the portable information terminal shown in FIG. 10C and FIG. 10D, when the display portion 7402 is touched with a finger or the like, It is also possible to input information, such as making a phone call or Operations such as creating an e-mail can be performed by touching the display portion 7402 with a finger or the like. can.

[0261] The screen of the display unit 7402 has three main modes. The first is a mode that mainly displays images. The first mode is a display mode, the second is an input mode for inputting information such as characters, and the third mode is a display mode. This is a display + input mode that combines the display mode and the input mode.

[0262] For example, when making a call or composing an e-mail, the display unit 7402 is used for inputting characters. The main input mode is the character input mode, and the input operation of the characters displayed on the screen can be performed. In this case, a keyboard or number buttons can be displayed on most of the screen of the display unit 7402. preferable.

[0263] In addition, the mobile information terminal has a sensor for detecting the inclination such as a gyro or an acceleration sensor. By providing a detection device for detecting the orientation of the portable information terminal (portrait or landscape), the display unit 740 The screen display can be switched automatically between the two.

[0264] The screen mode can be changed by touching the display portion 7402 or by operating the housing 7401. The type of image displayed on the display unit 7402 can be selected by operating the operation button 7403. For example, the image signal to be displayed on the display unit may be changed by If the data is text data, the mode switches to input mode.

[0265] In the input mode, the optical sensor of the display unit 7402 detects a signal and displays the If there is no input by touch operation on the display unit 7402 for a certain period of time, the screen mode is changed to the input mode. Alternatively, the display mode may be switched from the display mode to the display mode.

[0266] The display unit 7402 can also function as an image sensor. By touching 402 with a palm or a finger and capturing an image of a palm print, fingerprint, or the like, personal authentication can be performed. In addition, a backlight that emits near-infrared light for the display unit or a sensing device that emits near-infrared light for the display unit By using a light source, it is also possible to image finger veins, palm veins, etc.

[0267] The electronic device may be used by appropriately combining the configurations shown in this specification. do.

[0268] In addition, a light-emitting element including an organic compound according to one embodiment of the present invention is preferably used in a display portion. Since the light-emitting element can be a light-emitting element with good light-emitting efficiency, it is possible to realize a light-emitting element with low power consumption. In addition, it is easy to provide a light emitting element with high heat resistance.

[0269] An automobile according to one embodiment of the present invention is shown in FIG. The board is equipped with light-emitting elements. It is preferable to use the organic compound according to one embodiment of the present invention. Moreover, by using the organic compound, a light-emitting element with low power consumption can be obtained. In addition, this reduces power consumption in the display areas 5000 to 5005. , and is suitable for in-vehicle use.

[0270] The display area 5000 and the display area 5001 are light-emitting devices provided on the windshield of an automobile. The display device uses a light-emitting element. The light-emitting element is connected to a first electrode and a second electrode. By using electrodes that can be connected to each other, the other side can be seen through, making it a so-called see-through display. If the display is see-through, it can be installed on the windshield of a car. Even if the device is placed in a place where it is not obstructing the view, When transistors are provided, organic transistors made of organic semiconductor materials or oxides are used. A light-transmitting transistor, such as a transistor using a semiconductor, is preferably used.

[0271] The display area 5002 is a display device that uses light-emitting elements provided in the pillar portion. In the area 5002, an image from an imaging means provided on the vehicle body is projected, and the pillar It can also complement the view obstructed by the dashboard. The display area 5003 is a field of view blocked by the vehicle body, and is captured by an imaging means provided on the outside of the vehicle. By projecting images from the surroundings, blind spots can be filled and safety can be improved. By projecting images that complement the unsightly parts, safety checks can be performed more naturally and without discomfort. It is possible.

[0272] The display area 5004 and the display area 5005 display navigation information, a speedometer, RPM, and mileage. It can provide information such as distance traveled, fuel level, gear status, air conditioning settings, and much more. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in the display areas 5000 to 5003. The display areas 5000 to 5005 can also be used as lighting devices.

[0273] 12(A) to 12(C) show a foldable portable information terminal 9310. FIG. 12(A) shows the portable information terminal 9310 in an unfolded state. FIG. 12(B) shows the portable information terminal 9310 in an unfolded state. 9 shows a portable information terminal 9310 in a folded state changing from one to the other. FIG. 12C shows the portable information terminal 9310 in a folded state. The 0 is highly portable when folded and has a large, seamless display area when unfolded. The display is easy to see depending on the area.

[0274] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. The two housings 9315 are bent via the hinge 9313, making the device portable. The information terminal 9310 can be reversibly transformed from an unfolded state to a folded state. The light-emitting device according to one embodiment of the present invention can be used for the display panel 9311. The display area 9312 in the display area 9311 is on the side of the portable information terminal 9310 in the folded state. The display area 9312 displays information icons and frequently used applications. You can display shortcuts to programs and other information, and check the status of apps, etc. It can start up smoothly.

[0275] In the above manner, an electronic device can be obtained by using the light-emitting device which is one embodiment of the present invention. The electronic devices to which the present invention can be applied are not limited to those shown in the present embodiment, but can be used in any field. The present invention can be applied to various electronic devices.

[0276] Note that the structure described in this embodiment mode may be used in appropriate combination with structures described in other embodiments. There can be. [Explanation of symbols]

[0277] 100 Substrates 101 Sealing substrate 102 First electrode 102R First electrode 102G First electrode 102B First electrode 102Y First electrode 102Rt transparent conductive film 102Gt Transparent conductive film 102Bt transparent conductive film 102Yt transparent conductive film 103 EL layer 103a EL layer 103b First light emitting unit 103c Second light emitting unit 103d EL layer 103e First EL layer 103f Second EL layer 103g 3rd EL layer 103h 4th EL layer 103i 1st EL layer 103j Second EL layer 103k 3rd EL layer 103m 4th EL layer 104 Second electrode 105 Black Matrix 106R Color conversion layer 106G Color conversion layer 106Y Color conversion layer 107G Color Filter 107B Color Filter 107Y Color Filter 109 Middle Class 114 Hole injection layer 115 Hole transport layer 116 Light-emitting layer 116d-1 First light-emitting layer 116d-2 Second light-emitting layer 117 Electron transport layer 118 Electron injection layer 601 Driver circuit section (source line driver circuit) 602 Pixel section 603 Drive circuit section (gate line drive circuit) 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (Flexible Printed Circuit) 610 Element Substrate 611 Switching FET 612 Current Control FET 613 First electrode 614 Insulation 616 EL layer 617 Second Electrode 618 Light-emitting element 623 n-channel FET 624 p-channel FET 625 Dry material 951 Board 952 Electrode 953 Insulation Layer 954 Partition layer 955 EL layer 956 Electrode 1001 Board 1002 Undercoat insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 First interlayer insulating film 1021 Second interlayer insulating film 1022 Electrode 1024Y First electrode of light emitting element 1024R First electrode of light emitting element 1024G First electrode of light-emitting element 1024B First electrode of light emitting element 1025 Bulkhead 1028 EL layer 1029 Second electrode of light emitting element 1031 Sealing substrate 1032 Sealing material 1033 Transparent substrate 1034R Red color conversion layer 1034G Green color conversion layer 1034B Blue color filter layer 1034Y Yellow color conversion layer 1035 Black layer (black matrix) 1037 Third interlayer insulating film 1040 Pixel section 1041 Drive circuit section 1042 Periphery 5000 display area 5001 Display area 5002 Display area 5003 Display area 5004 Display area 5005 Display area 7101 Case 7103 Display section 7105 Stand 7107 Display section 7109 Operation key 7110 Remote control device 7201 Main unit 7202 Case 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing Device 7210 Second display unit 7401 Case 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Mike 9310 Mobile Information Terminal 9311 Display Panel 9312 Display area 9313 Hinge 9315 Case

Claims

[Claim 1] A light emitting device having a first light emitting element, a second light emitting element, and a third light emitting element, the first light-emitting element, the second light-emitting element, and the third light-emitting element have a common EL layer; the EL layer has a layer containing a light-emitting material that exhibits blue fluorescence and a layer containing a light-emitting material that exhibits green phosphorescence, a light emitting device, characterized in that light emitted from the third light emitting element is incident on a first color conversion layer;

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