Light-emitting device and electronic appliance

Abstract

To provide a light-emitting device, an electronic appliance, and a display device with low consumption power.SOLUTION: A light-emitting device has 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 exhibiting blue fluorescent light, and a light-emitting material exhibiting yellow or green fluorescent light. The light emitted from the second light-emitting element enters a color filter layer or a second color conversion layer. The light emitted from the third light-emitting element enters a first color conversion layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One aspect 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 etc. 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, driving methods thereof, or The manufacturing method thereof can be cited as an example. [Background technology]

[0002] With potential such as thinness and light weight, fast response to input signals, and low power consumption, it is expected to become a next-generation Light-emitting devices (organic EL devices) that use organic compounds as light-emitting materials are being used in modern lighting and display devices. 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 The spectrum of light emitted by a luminescent material is determined by the characteristics of that luminescent material. By using different types of organic compounds as luminescent materials, various A light-emitting element that emits light of various colors can be obtained.

[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. Furthermore, in order to improve color reproduction and image quality, a microcavity structure and Color filters are also used to enhance the color purity of emitted light.

[0005] In addition, in order to reduce power consumption, the molecular structure of the light-emitting material used is changed. Various measures have been taken, such as controlling the materials, their composition, and structure. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-129586 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 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 has 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 containing 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] Alternatively, in the above structure, one embodiment of the present invention is such that 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] Alternatively, in the above structure, one embodiment of the present invention is such that the light emitted from the second light-emitting element is A light emitting device characterized in that the light is emitted from the light emitting device through a color filter that transmits green light. It is an optical device.

[0013] Alternatively, in the above structure, one embodiment of the present invention is such that light emitted from the second light-emitting element is This is a light-emitting device in which light is incident on 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 to third light-emitting elements are 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 to third light-emitting elements are The optical element has a layer containing a light-emitting material that exhibits blue fluorescence and a layer containing 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, wherein the first color conversion layer and the second color conversion layer are 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, wherein the first color conversion layer and the second color conversion layer are The light-emitting device has a PL quantum yield of greater than 53.3% for 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, wherein the first color conversion layer and the second color conversion layer are The light-emitting device has a PL quantum yield of greater than 66% in one or both of the layers.

[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 have 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 contain the green phosphorescent light-emitting material. The layers included in the third light-emitting element are the same layer, and 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.

[0020] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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 containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

[0021] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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. a layer containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; 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 of 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. and the EL layer of the third configuration includes the 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 may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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 containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

[0024] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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. a layer containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

[0025] Alternatively, in the above-described structure, 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 exhibiting green phosphorescence. and a material, wherein the first organic compound and the second organic compound are exciplex-forming exciplexes. It is an optical device.

[0027] Alternatively, in the above structure, one embodiment of the present invention is a compound semiconductor laser device, wherein the emission spectrum of the exciplex is This is a light-emitting device that 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 share 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] Alternatively, in the above structure, one embodiment of the present invention is such that 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 in which the second light-emitting element 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 to third light-emitting elements are 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 to third light-emitting elements are The optical element has 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-described structure, 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-described structure, 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-described structure, 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-described structure, 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 has 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 has 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 from the second light-emitting element is incident on the second color conversion layer, and the light emitted from 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 element is incident on the first color conversion layer.

[0038] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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, and a layer containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

[0039] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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. a layer containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

[0040] Alternatively, in one embodiment of the present invention, in the above structure, the light-emitting device further includes a fourth light-emitting element. The light emitted from the fourth light-emitting element is emitted through a color filter that transmits yellow light. It is a light-emitting device that emits light from the light device.

[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, and the third light-emitting element The light-emitting element has an EL layer of an eighth configuration, and the EL layer of the eighth configuration exhibits blue fluorescence. a layer containing a light-emitting material and a layer containing 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, and the EL layer of the eighth configuration, 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 from the light emitting element 3 is incident on the first color conversion layer.

[0042] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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, and a layer containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

[0043] Alternatively, one embodiment of the present invention may further include the above-described structure, wherein the light-emitting material that emits blue fluorescence is contained. 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. a layer containing the light-emitting material exhibiting blue fluorescence and a layer containing 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; is.

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

[0045] Alternatively, in the above-described structure, 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 having a light-emitting efficiency of 50% or more.

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

[0047] 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 exhibiting yellow phosphorescence. and a material, wherein the first organic compound and the second organic compound are exciplex-forming exciplexes. It is an optical device.

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

[0049] Alternatively, in the above structure, one embodiment of the present invention is such that the light emitted from the first color conversion layer is red. The light emitting device is characterized by emitting light of the type described above.

[0050] Alternatively, in one embodiment of the present invention, in the above structure, the light-emitting device further includes 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 one aspect of the present invention, in the above-mentioned configuration, the first color conversion layer uses quantum dots. This is a light-emitting device in which a color conversion layer is used.

[0052] Another embodiment of the present invention is a light-emitting device having the above structure, a sensor, an operation button, a speaker, and a light-emitting element. It is an electronic device having a camera or a microphone. [Effects 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-described objects. [Brief explanation of the drawings]

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

[0056] Hereinafter, embodiments 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 may be modified without departing from the spirit and scope of the present invention. It will be readily apparent to those skilled in the art that various modifications can be made to the above. 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) (D) and (E).

[0057] <Conversion from a tandem device 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 the first electrode is different. The optical element has the first electrode 102B, the second light emitting element has the first electrode 102G, and the third light emitting element has the first electrode 102C. The elements each have 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 structure typified by the structure 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 second light-emitting unit 103a via an 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 (anode) side. A typical structure is one in which a light-emitting layer 116, an electron transport layer 117, an electron injection layer 118, etc. are provided. In such a structure, the light-emitting material may be contained in the light-emitting layer 116. When the second 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. 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 compound 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 preferable configuration because 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. Furthermore, the light emitted from the second light emitting element passes through the color filter 107G and exits the light emitting device. 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. 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 In order to efficiently obtain the three colors 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 and efficient. 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, the same as in Figure 5(A), and one of the light-emitting units The light-emitting layer of one unit is a fluorescent light-emitting layer using a blue fluorescent material, and the light-emitting layer of the other unit is a red fluorescent material. The phosphorescent layer is made of a color phosphorescent material and a green 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 layer is 100%, the external quantum efficiency of the blue pixel is 25 ×χ CF (However, χ CF is the light extraction efficiency when a color filter is used, and χ CF = Maximum transmittance of the color filter used × χ A Also, 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 assumed to be common to all light-emitting devices. 50×χ each CF % (To share the excitons between green and red. For simplicity, we will share half each. Let us assume 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 used, the A %), and the external quantum efficiency of the red pixel is 125 ×χ CC % (however, 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 Also, 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%.) This 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 %, which is twice as effective In addition, the external quantum efficiency of the red pixel is compared between the conventional configuration and this configuration. Then, 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 efficiency of the color conversion layer are the same, the This means that the PL quantum yield of the color conversion layer is equal to the transmittance of the color filter. If the external quantum efficiency is 40% or more, the red pixel will have better external quantum efficiency than the conventional red pixel. This allows a light emitting device with low power consumption. The color filter 107G can be replaced with a color conversion layer 106G. The external quantum efficiency of the pixel 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 40% or more, it is better than the conventional green pixel. It is possible to create a green pixel with high external quantum efficiency, making it possible to create a light-emitting device with low power consumption. This becomes:

[0066] As shown in FIG. 2(A), a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1(A). A fourth light-emitting element is provided between the first electrode 102Y and the second electrode 104. The light-emitting device has an EL layer including a first light-emitting unit 103b and a second light-emitting unit 103c. Furthermore, 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 the blue fluorescence with an internal quantum efficiency of 25%. % green phosphorescence is converted into color, so 125×χ CC %.

[0067] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. It has 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. 1(B) shows the light emission of one embodiment of the present invention using a single element utilizing blue fluorescence and green phosphorescence. The light-emitting device has at least one light-emitting element similar to the light-emitting device shown in FIG. The first to third light emitting elements are included, and the first light emitting element is a substrate 100, a sealing substrate 101, and a third light emitting element. First electrodes 102B, 102G, 102R, second electrode 104, black matrix 105 , color conversion layer 106R, color filter 107G, and color filter 107B are also shown in FIG. Since it 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. 5B. The light-emitting unit includes two light-emitting layers (first light-emitting layer 116d-1 and second light-emitting layer 116d The first light-emitting layer 116d has a single structure in which the first light-emitting layer 116d and the second light-emitting layer 116d are provided adjacent to each other. 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 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 first light-emitting material as a host material in addition to the light-emitting material. The present invention further comprises a first organic compound and a second organic compound, The compound forms an exciplex with the second organic compound, 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 allows for efficient energy transfer, making this a more desirable configuration. .

[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 the green color filter 107G. The light emitted from the third light emitting element is incident on 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 The external quantum efficiency of each pixel in a light-emitting device having the above configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[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 is required that emits light with an intensity corresponding to the wavelength of each color. Considering the balance between practicality and efficiency, blue fluorescent materials, red phosphorescent materials, and green phosphorescent materials are used. If a phosphorescent material is used, the first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 may be formed of a 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 element 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 x 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 Figure 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 with 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 %.

[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 an efficiency improvement of approximately 1.5 times is expected even for green pixels. 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 efficiency of the color conversion layer are the same, the This indicates that the PL quantum yield of the color conversion layer is higher than that of the color filter. If the transmittance of the pixel 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 obtained.

[0076] In addition, as shown in FIG. 2(B), a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1(B). A fourth light-emitting element is provided 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 fourth light-emitting element has a single EL layer. The light is incident on the color conversion layer 106Y, which emits yellow light. The efficiency is obtained by color conversion of blue fluorescence and green phosphorescence, so it is 62.5 × χ CC %.

[0077] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. It has 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 (single coating) 1> FIG. 1C shows one 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 first to third light emitting elements, and the substrate 100 and the 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 of the light emitting device shown in FIG. 1(A), and therefore will not be described. is omitted.

[0079] In the light-emitting device shown in FIG. 1C, the first light-emitting element has an EL layer of the first configuration, and the second The second light-emitting element and the third light-emitting element have an EL layer with 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 103f, and a The EL layer of the second configuration is a laminate of the EL layer 103g and the 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 stacked. It is completed.

[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 is the EL layer 103d in FIG. The EL layer of the second configuration has the same structure as the EL layer 103a in FIG. 5(C). It becomes successful.

[0082] The EL layer of the first configuration and the EL layer of the second configuration can be formed by coating them separately in one step. By simply applying the coating once, a single layer consisting of a regular fluorescent light-emitting layer and a phosphorescent light-emitting layer can be produced. As compared with light emitting devices 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 transfer occurs from the exciplex to the luminescent material. In addition, it is preferable that the emission spectrum of the exciplex and the absorption band of the light-emitting material on the longest wavelength side are The overlapping structure is more preferable because 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. When the electrode is an anode, the first EL layer 103e is an electron transport layer in FIG. 5B, the fourth EL layer 103h is the hole injection layer 114 and the electron injection layer 118. The second EL layer 103f and the third EL layer 103g correspond to the hole transport layer 115 and the It is preferable that the layer has a higher hole transporting property than an electron transporting property.

[0085] In addition, in FIG. 1C, the second EL layer 103f is formed before the third EL layer 103g. However, 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 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 a higher electron transporting property than a hole transporting property.

[0086] The light emitted from the third light emitting element is incident on the color conversion layer 106R. It is to be noted that 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 element can be emitted outside the light emitting device after passing 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.

[0087] Here, the external quantum efficiency of each pixel in the light-emitting device having the above-mentioned configuration and the The external quantum efficiency of each pixel in a light-emitting device having this configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[0088] First, the outer periphery of each pixel in a light-emitting device having a different configuration from the above-mentioned configuration without using a color conversion layer The structure of the light-emitting element in the light-emitting device is the same as that of the light-emitting element in Figure 1(C). 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 three colors efficiently, light with intensity corresponding to the wavelengths of 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 this case, 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 based on the Assuming that the efficiency of the phosphorescent layer is 25% and the efficiency of 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%.

[0090] Next, considering the 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 color filter, the CF %), and the external quantum efficiency of the red pixel is 100×χ C C %. As described above, by using the structure of one embodiment of the present invention, the luminous efficiency is very high. Therefore, 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 is 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 will be doubled. This means that the PL quantum efficiency of the color conversion layer is expected to be 50% of the transmittance of the color filter. % or more, it is possible to obtain a red pixel with better external quantum efficiency than conventional red pixels. This makes it possible to provide a light emitting device with low power consumption.

[0092] In addition, as shown in FIG. 2(C), a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 1(C). A fourth light-emitting element is provided between the first electrode 102Y and the second electrode 104. The light emitted from the fourth light-emitting element is converted into a color conversion layer 106. The light is incident on the yellow pixel, and the color conversion layer 106Y emits yellow light. The external quantum efficiency of this yellow pixel is Because it is obtained by color conversion of green phosphorescence, 100 × χ CC %.

[0093] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. It has 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 (single coating) 2> FIG. 1(D) shows one 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 first to third light emitting elements, and the substrate 100 and the 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 of the light emitting device shown in FIG. 1(A), and therefore will not be described. is omitted.

[0095] In the light-emitting device shown in FIG. 1(D), the first light-emitting element has an EL layer of the third structure, The second light-emitting element and the third light-emitting element have an EL layer with 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 stacked. It is completed.

[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 is the EL layer 103d in FIG. The EL layer of the third configuration has the same structure as the EL layer 103a in FIG. 5(C). It becomes successful.

[0098] The EL layer of the third configuration and the EL layer of the fourth configuration can be formed by coating them separately in one step. By simply applying the coating once, a single layer consisting of a regular fluorescent light-emitting layer and a phosphorescent light-emitting layer can be produced. As compared with light emitting devices 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 the first organic EL layer as a host material in addition to the light-emitting material. The compound 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 luminescent material. In addition, it is preferable that the emission spectrum of the exciplex and the longest wavelength side of the luminescent material are the same. When the absorption bands overlap, energy transfer becomes possible with high efficiency, which is a more preferable configuration. 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 elements. 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 electron injection layer 118 in FIG. The second EL layer 103j and the third EL layer 103k correspond to the hole transport layer 115. It is preferable to use a layer having higher electron transporting property than electron transmitting property.

[0101] In addition, in FIG. 1(D), 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 both k and k are layers 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 both It is preferable that the layer has a higher electron transporting property than a hole transporting property.

[0102] The light emitted from the third light emitting element is incident on the color conversion layer 106R. It is to be noted that 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 element can be emitted outside the light emitting device after passing 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 the The external quantum efficiency of each pixel in a light-emitting device having this configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[0104] First, the outer periphery of each pixel in a light-emitting device having a different configuration from the above-mentioned configuration without using a color conversion layer The structure of the light-emitting element in the light-emitting device is the same as that of the light-emitting element shown in Figure 1(D). 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 three colors efficiently, light with intensity corresponding to the wavelengths of 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. Preferably, the third EL layer 103k uses a red phosphorescent material and a green phosphorescent material. The second and third light-emitting elements produce light that is a combination of red and green light, The second light emitting element emits green light by passing through a green color filter and emitting the light to the outside of the light emitting device. The third light emitting element emits light outside the light emitting device through a red color filter. When emitted, 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 based on the Assuming that the efficiency of the phosphorescent layer is 25% and the efficiency of 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 %.

[0106] Next, considering the 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. When using a color filter, the 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-emitting A light emitting device with good efficiency can be obtained.

[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 is 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 will be doubled. This means that the PL quantum efficiency of the color conversion layer is expected to be 50% of the transmittance of the color filter. % or more, it is possible to obtain a red pixel with better external quantum efficiency than conventional red pixels. This makes it possible to provide a light emitting device with low power consumption.

[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). A fourth light-emitting element is provided 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 is incident on the yellow pixel, and the color conversion layer 106Y emits yellow light. The external quantum efficiency of this yellow pixel is Because it is obtained by color conversion of green phosphorescence, 100 × χ CC %.

[0109] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. It has 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, but the first electrode is different. B, the second light emitting element has the first electrode 102G, and the third light emitting element has the first electrode 102R. The sealing substrate 101 also 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 106B is a color filter that transmits blue light. The color conversion layer 106R contains a color conversion material that emits red light. It contains color-changing substances.

[0111] In FIG. 3A, the EL layer 103 is a tandem structure typified by the structure 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 second light-emitting unit 103a via an 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 (anode) side. A typical structure is one in which a light-emitting layer 116, an electron transport layer 117, an electron injection layer 118, etc. are provided. In such a structure, the light-emitting material may be contained in the light-emitting layer 116. When the second 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. 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 light. The light obtained is a combination of the fluorescent light and the yellow phosphorescence. The organic compound 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 preferable configuration because 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. Furthermore, the light emitted from the second light emitting element is incident on color conversion layer 106G, and The third light emitting element is excited by the incident light and emits green light. The light emitted from the color conversion layer 106R is incident on the 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 should be formed so as to amplify blue light. As shown in FIG. 3(A), a transparent conductive film (transparent conductive film 102B) having a desired thickness is formed on the first electrode. t, transparent conductive film 102Gt, transparent conductive film 102Rt) can be 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 transparent light is amplified in the optical element so as to amplify blue light, and the transparent light is amplified in the third light-emitting element so as 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 the The external quantum efficiency of each pixel in a light-emitting device having this configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[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 made using the following: A light-emitting device using a normal tandem element can efficiently emit the three colors red, green, and blue. To achieve this, it is effective to use luminescent materials that exhibit the respective luminescent wavelengths, and this is both practical and effective. In consideration of the balance between the efficiency and the blue fluorescent material, the red phosphorescent material and the green phosphorescent material are often used. The same two-stage tandem structure as in Figure 5(A) is used, 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 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, let us consider a light-emitting device having the above configuration (the configuration of FIG. 3(A)). External quantum efficiency of blue pixel is 25×χ CF %, green pixels are 25×χ CC %, red pixels 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 element, A light-emitting element with very high light-emitting 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 improvement in efficiency can be expected. This means that 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 conventional red pixels.

[0120] Also, 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 that corresponds to yellow light emission. In this case, a transparent conductive The light emitted from the fourth light emitting element may be reflected by a color filter. The external quantum efficiency of the yellow pixel is 100 ×χ CF %. Note that color filter 107Y may be replaced with yellow color conversion layer 106Y. In this case, the external quantum efficiency of the yellow pixel is 125×χ CC %.

[0121] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. It has 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 Figure 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 color conversion layer 106R, which is the first color conversion layer provided in the red pixel, If the PL quantum yield of the light emitting 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 the light emission of one embodiment of the present invention using a single element utilizing blue fluorescence and yellow phosphorescence. The light-emitting device has at least one light-emitting element similar to the light-emitting device shown in FIG. The first to third light emitting elements are included, and the first light emitting element is a substrate 100, a sealing substrate 101, and a third light emitting element. First electrodes 102B, 102G, 102R, second electrode 104, black matrix 105 , color conversion layer 106R, color conversion layer 106G, and color filter 107B are also shown in FIG. Since this is the same as the light emitting device shown in FIG.

[0124] In FIG. 3(B), the EL layer 103d is a thin film EL layer, as typified by the structure shown in FIG. 5(B). The EL layer has a group structure. The first light-emitting layer 116d-1 and the second light-emitting layer 116d-2 The layers may be formed in contact with each other, or a separation layer having a thickness of more than 0 nm and not more than 20 nm may be provided between them. The thickness of the separation layer is preferably 1 nm or more and 10 nm or less. 103d is common to the first to third light emitting elements.

[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 in addition to the light-emitting material. 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 and the compound form 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 if the absorption bands on the long wavelength side overlap, as 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. Furthermore, the light emitted from the second light emitting element is incident on color conversion layer 106G, and The third emitter, O6G, is excited by the incident light and emits green light. Light emitted from the photoelectric 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. 3(A). The color conversion layer 106G cannot absorb yellow light. Therefore, a resonant structure or a color filter is used to remove the yellow light that is 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 resonant structure is formed by depositing a transparent conductive film ( Forming the transparent conductive film 102Bt, the transparent conductive film 102Gt, and the transparent conductive film 102Rt It should be noted that the light that cannot be absorbed by the first light emitting element and the third light emitting element can be provided by the following method. 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 amplifies blue light, and the third light-emitting element amplifies 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 The external quantum efficiency of each pixel in a light-emitting device having the above configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[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 placed in one light-emitting unit. It is assumed that the device structure has a single 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 It is usually effective to use luminescent materials that exhibit the respective luminescent wavelengths, and this is practical and efficient. In consideration of the balance between these, 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 in the other layer. The internal quantum efficiency of each light-emitting layer can be calculated by comparing the fluorescent light-emitting layer with the green phosphorescent material. 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 %.

[0130] Next, consider a light-emitting device having the configuration shown in Figure 3(B). In addition to the same assumptions, The distribution of 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 not using a resonant structure. Resonant structure When the blue light is attenuated, the CC %). By using the structure of one embodiment of the present invention, a light-emitting element having a good external quantum efficiency of a red pixel can be obtained. You will be able to do this.

[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 approximately 1.5 times. In the original configuration, the conventional CF %, while this configuration is 62.5×χ CC % Therefore, 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 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. A fourth light-emitting element is provided between the first electrode 102Y and the second electrode 104. The light emitted from the fourth light emitting element is reflected by the color filter 10. Since the light is emitted to the outside of the light-emitting device via 7Y, the external quantum efficiency of the yellow pixel is 50×χ CF %. When forming a resonant structure, it should be formed so that yellow light is amplified. As shown in FIG. 4(B), the structure is such that a transparent conductive film 102Yt having a desired thickness is formed on the 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 configured in this way 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 configuration of FIG. 4(B), white light can be expressed using only red, blue, and yellow light. Therefore, the efficiency of green light has almost no effect on power consumption. 50×χ CF %, the first color conversion layer provided in the red pixel The PL quantum yield of the red color filter 106R is greater than 53.3% of the transmittance (%) of the red color filter. If this is possible, it is possible to obtain a light emitting device with better efficiency than conventional light emitting devices. When a resonant structure is formed, the PL quantum efficiency of the color conversion layer 106R is higher than that of the red color filter. A light-emitting device with a transmittance (%) of more than 66%, making it more efficient than conventional light-emitting devices can be obtained.

[0135] <Conversion from blue fluorescent single element and yellow phosphorescent single element (single 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 first to third light emitting elements, and the substrate 100 and the sealing substrate 10 1, first electrodes 102B, 102G, 102R, second electrode 104, black matrix 105, color conversion layer 106G, and color conversion layer 106R are the same as those of the light-emitting device shown in FIG. 3(A). Since the procedures 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 having the sixth configuration, and the third light-emitting element has an EL layer having the sixth configuration.

[0137] The EL layer of the fifth configuration is a first EL layer 103e, a second EL layer 103f, a third EL layer 103c, and a The sixth EL layer is a laminate of the fourth EL layer 103g and the 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 stacked. It is completed.

[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 is the EL layer 103d in FIG. The EL layer of the sixth configuration has the same structure as the EL layer 103a in FIG. 5(C). It becomes successful.

[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 ingredient 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 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. When the electrode is an anode, the first EL layer 103e is an electron transport layer in FIG. 5B, the fourth EL layer 103h is the hole injection layer 114 and the electron injection layer 118. The second EL layer 103f and the third EL layer 103g correspond to the hole transport layer 115 and the For the same reasons as above, it is preferable to use a layer having a higher hole transporting property than an electron transporting property.

[0141] In addition, in FIG. 3C, the second EL layer 103f is formed before the third EL layer 103g. However, 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 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 a higher electron transporting property than a hole transporting property.

[0142] Blue light can be obtained from the first light-emitting element. By irradiating light onto color conversion layer 106G, green light can be emitted from color conversion layer 106G. Red light can be obtained by making the light emitted from the third light emitting element incident on color conversion layer 106R. The light emitted from the first light emitting element passes through a color filter. The light may be emitted outside the optical device. When the light is irradiated through the cathode, light emission with 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 The external quantum efficiency of each pixel in a light-emitting device having the above configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[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. 3(C) is assumed to be the same as that of the light emitting element in the light emitting device in FIG. Regarding the light-emitting element No. 2, in FIG. 3(C) it has an EL layer of the fifth configuration. 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, It is possible to use light-emitting materials that emit light having intensities at wavelengths corresponding to red, green, and blue. In terms of practicality and efficiency, blue fluorescent materials, red phosphorescent materials, and green phosphorescent materials are preferred. A blue fluorescent material is often used for the second EL layer 103f, and a blue 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, light is emitted to the outside of the light emitting device through a green color filter, and thus green light is emitted. The third pixel emits light outside the light-emitting device through a red color filter. This produces 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 % (color filter not included) When using a color filter, use 25×χ CF %), outside the green and red pixels The internal quantum efficiency is 50×χ CF % (using color filter).

[0147] Next, consider the light-emitting device having the configuration shown in Figure 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 aspect 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. You will be able to do it.

[0148] Here, when comparing the external quantum efficiency of the red pixel with the previously described configuration, the conventional In the configuration of 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 improvement in efficiency can be expected. This means that the PL quantum efficiency of the color conversion layer must be 50% or more of the transmittance of the color filter. This results in a red pixel with 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] Also, as shown in FIG. 4(C), a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 3(C). A fourth light-emitting element is provided between the first electrode 102Y and the second electrode 104. The external quantum efficiency of the yellow pixel is 1 / 4 of the fourth luminescence layer. When 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 used A %.

[0150] With a light-emitting device configured in this way, images can be displayed in four colors: red, green, blue, and yellow. It has 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 almost no effect on power consumption. However, the PL quantum efficiency of color conversion layer 106R, which is the first color conversion layer provided in the red pixel, is If the transmittance of the color filter is 50% or more, the red light emission is equivalent to that of conventional elements. As a result, a light emitting device with high efficiency can be obtained.

[0152] The light emitting device having this configuration can achieve these effects with a single application of different colors.

[0153] <Conversion from blue fluorescent single element and yellow phosphorescent single element (single 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 first to third light emitting elements, and the substrate 100 and the sealing substrate 10 1, first electrodes 102B, 102G, 102R, second electrode 104, black matrix 105, color conversion layer 106G, and color conversion layer 106R are the same as those of the light-emitting device shown in FIG. 3(A). Since the procedures are similar, the explanation will be omitted.

[0154] In the light emitting device shown in FIG. 3(D), 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.

[0155] The seventh EL layer structure includes a first EL layer 103i, a second EL layer 103j, and a fourth EL layer 103i. The eighth EL layer is a laminate of the first EL layer 103i and the second EL layer 103m. A second EL layer 103j, a third EL layer 103k, and a fourth EL layer 103m are stacked. 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 is the same as the EL layer 103a in FIG. The EL layer of the eighth configuration has the same structure as the EL layer 103d in FIG. 5(B). It becomes successful.

[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 first EL layer as a host material. The composition further comprises a first organic compound and a second organic compound. The organic compound of formula 2 forms an exciplex, and energy transfer from the exciplex to the light-emitting material occurs. In addition, the longest wavelength region of the emission spectrum of the exciplex and the luminescent material is When the absorption bands of .

[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 layers have a higher hole transporting property 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. When the electrode is an anode, the first EL layer 103i is an electron transport layer in FIG. 5(B) and the electron injection layer 117 and the electron injection layer 118, and the fourth EL layer 103m is the hole injection layer 114 and the electron injection layer 118 in FIG. and the hole transport layer 115, and the second EL layer 103j and the third EL layer 103k are both positive For the same reasons as above, it is preferable to use a layer having a higher electron transporting property than a hole transporting property.

[0159] In addition, in FIG. 3(D), 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 both k and k are layers 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 both It is preferable that the layer has a higher electron transporting property than a hole transporting property.

[0160] Blue light can be obtained from the first light-emitting element. 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 light emitting element 3 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 does not pass through a color filter, it is possible to obtain light with good efficiency. When this is done, 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 The external quantum efficiency of each pixel in a light-emitting device having the above configuration is considered. Although the carrier balance and exciton generation probability of the light-emitting element used in the device are similar, Let's say.

[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 of FIG. 3(D). The second light-emitting element has an EL layer of the seventh configuration in FIG. 3(D), but In the device, this is the EL layer of the eighth configuration.

[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. A color phosphorescent material and a green phosphorescent material may be used.

[0164] The third EL layer 103k of the eighth configuration contains red and green phosphorescent materials. Therefore, light that is a combination of red and green light is obtained from the second and third light-emitting elements. 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 green light through a red color filter. Red light is obtained by emitting the light outside 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 possible to create red pixels with better external quantum efficiency than conventional red pixels, and reduce power consumption. Therefore, a light emitting device with a small size can be obtained.

[0168] As shown in FIG. 4(D), a fourth light-emitting element constituting a yellow pixel is added to the configuration of FIG. 3(D). A fourth light-emitting element is provided between the first electrode 102Y and the second electrode 104. The external quantum efficiency of the yellow pixel is 4. When 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 used A %.

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

[0170] In 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 almost no effect on power consumption. However, the PL quantum efficiency of color conversion layer 106R, which is the first color conversion layer provided in the red pixel, is If the transmittance of the color filter is 50% or more, blue and red light can be emitted by conventional devices. This is equivalent to the above, and a light emitting device with high efficiency can be obtained.

[0171] The light emitting device having this configuration can achieve these effects with a single application of different colors.

[0172] The color conversion layers 106R, 106G, and 106Y used in the above-described light emitting device are Any device that can convert light of the desired wavelength with the desired efficiency can be used. Typically, a color conversion layer using a fluorescent dye or a color conversion layer using quantum dots is used. 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 preferable configuration because it can provide a light emitting device with good color reproducibility. .

[0173] <Light-emitting element> Next, examples of light-emitting elements according to embodiments of the present invention will be described with reference to FIGS. 5A to 5C. 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 composed of the EL layer 103a and the EL layer 103d. The following description will be given assuming that the first electrode 102 functions as an anode and the second electrode 104 functions as a cathode. do.

[0175] The first electrode 102 functions as an anode, so it is made of a material with 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 preferable. in Oxide), indium oxide-tin oxide containing silicon or silicon oxide, Indium oxide - zinc oxide, tungsten oxide and zinc oxide containing indium oxide ( These conductive metal oxide films are usually formed by sputtering. However, it may also be prepared by applying the sol-gel method. Indium oxide-zinc oxide is made by adding 1 to 20 wt% of zinc oxide to indium oxide. There are also methods for forming the film by sputtering using a target containing the oxide. Indium oxide containing tungsten and zinc oxide (IWZO) is Tungsten oxide is 0.5 to 5 wt% and zinc oxide is 0.1 to 1 wt%. It can also be formed by sputtering using a target such as gold (Au), Platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum ( Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or metal Nitrides of materials (e.g., titanium nitride) can also be used. Graphene can also be used. The composite material described later is used for the layer of the EL layer 103 that is in contact with the first electrode 102. This allows the electrode material to be selected 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 blocking 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) basically has a hole injection layer laminated in order on the first electrode 102. 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 high hole injection properties. Use of zinc oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. In addition, phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (abbreviated as Cu phthalocyanine compounds such as 4,4'-bis[N-(4-diphenylamino) N,N'-bis(4-phenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), [bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1' -biphenyl)-4,4'-diamine (abbreviation: DNTPD), or 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 injection layer 114 is formed by adding an acceptor substance to a hole transporting substance. A composite material can be used. Note that the hole transporting material may contain an acceptor material. By using a material that has the same work function as the electrode, it is possible to select the material for forming the electrode regardless of the work function of the electrode. That is, 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. ,8-Tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TC NQ), chloranil, etc. Also included are transition metal oxides. Further examples include oxides of metals belonging to groups 4 to 8 in the periodic table. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molyb oxide Tungsten oxide, manganese oxide, and rhenium oxide are preferred due to their high electron-accepting properties. Among them, molybdenum oxide is particularly stable in the air, has low hygroscopicity, and is easy to handle. preferable.

[0179] As hole transporting substances used in composite materials, aromatic amine compounds, carbazole derivatives, Species such as organic compounds, aromatic hydrocarbons, and polymeric compounds (oligomers, dendrimers, polymers, etc.) Various organic compounds can be used. It is preferable that the organic compound has high hole transport properties. -6 cm 2 / Vs or later In the following, the hole transport in the composite material is Specific examples of organic compounds that can be used as transport materials 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 Phenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3 ,5-Tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc.

[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. You can be there.

[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)-9,9'-bianthryl, (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 hydrocarbons 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-vinyltriphenyl ether) 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 [(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used. can.

[0186] By forming a hole injection layer, the hole injection property is improved, and a light emitting device with a low driving voltage can be obtained. It is possible to obtain an optical element.

[0187] The hole transport layer 115 is a layer containing a substance with 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 can be used. , mainly 10 -6 cm 2 The composite material has a hole mobility of 1 / 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) (abbreviated as PVK) and poly(4-vinyl carbazole) Polymer compounds such as phenyltriphenylamine (PVTPA) can also be used. The layer containing the hole transporting substance may be a single layer or may be two or more layers containing 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 materials having electron transport properties that can be used as the host material are listed. A material having an anthracene skeleton or a material having an anthracene skeleton can be used.

[0189] Furthermore, 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. It is a layer that adjusts the carrier balance by suppressing the movement of electron carriers. This type of structure prevents electrons from penetrating the light-emitting layer. This is highly effective in suppressing problems that arise (for example, a reduction in the device life).

[0190] In addition, an electron transport layer 117 is formed 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 their compounds can be used. For example, The layer is made of a material containing an alkali metal or 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 mixed oxide of calcium and aluminum with high electron density. The electron-injecting layer 118 may be formed of a material having an electron-transporting property. By using a material containing an alkali metal or 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 forming the second electrode 104 is selected from those having a small work function (specifically, 3.8 eV Metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specific 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, rare earth metals such as AlLi), europium (Eu), ytterbium (Yb) and However, the second electrode 104 and the electron transport layer may be formed of a material other than the material itself. By providing an electron injection layer, it is possible to use Al, Ag, ITO, and ketone regardless of the magnitude of the work function. Various conductive materials such as indium oxide-tin oxide containing silicon or silicon oxide are used as the second These conductive materials can be used as the electrode 104. The film can be formed by a jet method, a spin coating method, or the like.

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

[0193] The electrodes may also be formed by a wet method using the sol-gel method, or by a paste of a metal material. Alternatively, the film may be formed by a dry method such as sputtering or vacuum deposition. 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 both the first electrode 102 and 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 element having a structure in which a plurality of light-emitting units are stacked (hereinafter referred to as a tandem light-emitting element) The embodiment of the light-emitting element (also referred to as a light-emitting element) will be described with reference to FIG. A pair of electrodes consisting of a first electrode 102 and a second electrode 104 is provided between the electrodes. 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 that.

[0196] In FIG. 5A, a first light-emitting element is disposed between the first electrode 102 and the second electrode 104. 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 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 between them. Therefore, the fluorescent light-emitting layer and the phosphorescent light-emitting layer are separated from each other. This makes it possible to easily achieve both fluorescent 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 material 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. Because of its excellent properties, it can be driven at low voltage and low current. When the anode side of the electrode is in contact with the intermediate layer, the intermediate layer acts as a hole injection layer for the light-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 up of a layer containing the above composite material and a layer made of other materials. For example, a layer including a composite material and a layer including an electron donor material may be formed. and a layer containing a compound having high electron transport properties. Alternatively, the transparent conductive film may be formed by combining a layer containing a composite material of an organic compound and a metal oxide. It may be formed by laminating

[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 may be formed by a very thin film of an alkali metal and an electron transporting layer. The electron-relay layer is made of an alkali metal and an electron-injecting material. The electron relay layer corresponds to the layer 118 and has the function of reducing the electron injection barrier. It has the function of preventing interaction between the metal film and the intermediate layer and transferring electrons smoothly. The LUMO level of the electron transporting material contained 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. The numerical values ​​of the energy levels are given by the LUMO of the electron transport material contained in the electron relay layer. The level is set to -5.0 eV or higher, preferably -5.0 eV or higher and -3.0 eV or lower. 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 with metal-oxygen bonds and aromatic ligands. The alkali metal film of the injection buffer layer plays the role of the 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 element sandwiched between the first light emitting unit 103b and the second light emitting unit 103c When a voltage is applied to the first electrode 102 and the second electrode 104, the intermediate layer 109 It is sufficient that the light-emitting element injects electrons into the light-emitting unit and 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 explained using 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 located close 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. Light emitted by combining blue fluorescence and green phosphorescence or blue fluorescence and yellow phosphorescence A clear light emission is obtained.

[0204] The phosphorescent light-emitting layer of the first light-emitting layer 116d-1 or the second light-emitting layer 116d-2 the layer contains 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 structure be such that energy transfer to the light-emitting substance occurs. By this, phosphorescence is not quenched even if the fluorescent-emitting layer and the phosphorescent-emitting layer are formed close to each other. 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-emitting layer, This causes a significant decrease in luminous efficiency. This is because the fluorescent emitting layer usually contains a 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 This is because the fluorescein-emitting compound migrates to the host material of the fluorescent-emitting layer and is deactivated without radiation. In the optical layer, the desired emission wavelength and good device characteristics can be achieved without using a substance with a condensed aromatic ring skeleton. Since it is difficult to achieve reliability, the fluorescent and phosphorescent layers are incorporated into the same EL layer. With this configuration, it is difficult to obtain a light emitting element with good characteristics.

[0206] In addition, the triplet excited state has a long relaxation time, so the diffusion distance of excitons is long, resulting in phosphorescence. Many of the excitons generated inside the layer also move to the fluorescent layer by diffusion, resulting in non-radiative 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. When the excited complex returns to 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 means that the energy between exciplexes is In principle, energy transfer and energy transfer from other substances to exciplexes are unlikely to occur.

[0209] Most of the excitons in the phosphorescent layer exist as exciplexes. The singlet excitation energy of the 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 separated so that the first organic compound is smaller than the second organic compound. From the exciplex to the first organic compound and the second organic compound by selecting the organic compound As mentioned above, the energy transfer between the two molecules can be prevented. Since there is almost no energy transfer between the two complexes, almost all of the excitation energy of the exciplex is The phosphorescent material is then 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 interface therebetween Energy transfer from the exciplex to the host material of the fluorescent emitting layer (especially triplet energy transfer) However, as mentioned above, exciton diffusion is rare 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., the interface between the fluorescent and phosphorescent emitting layers) and Therefore, the fluorescent and phosphorescent light-emitting layers are not necessarily Although it is not necessary for the two to be in contact with each other, even if they are in contact, the fluorescence and phosphorescence can be generated with high efficiency. In addition, if the thickness of the layer between the fluorescent and phosphorescent emitting layers is more than 0 nm and the thickness is less than 20 nm, both luminescence and light emission can be obtained. By providing a separation layer, the fluorescent-emitting layer can be separated. 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 light-emitting layer. This is a preferable configuration because it has a higher effect of suppressing the transfer of excitation energy.

[0211] Materials forming the light-emitting layer 116, the first light-emitting layer 116d-1, and the second light-emitting layer 116d-2 This is explained below.

[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)trimethylsilyl 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-carbazol-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 (9H-fluoren-9-yl)phenyl]-pyrene-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-tracking properties. It is preferred because it has high flexibility, excellent luminous efficiency and reliability.

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

[0214] The compounds that mainly exhibit green phosphorescence include tris(4-methyl-6-phenylpyrrolidone) 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 Lithium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonate 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 iridic compounds 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 [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 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 and (acetylacetonato)bis(3,5-dimethyl-2-phenylpiperidinium) (radinato)iridium(III) (abbreviation: Ir(mppr-Me)2(acac)), ( Acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate) Pyridines such as iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)) Organometallic iridium complexes with dithiazolinone 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 a pyrimidine skeleton are also outstanding in terms of reliability and luminous efficiency. This is particularly preferable because it is excellent in this respect.

[0216] The host material can be a material having various carriers such as a material having electron transport properties or a material having hole transport properties. 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. The organic compounds are preferably a combination that forms an exciplex. The compound and the second organic compound are a material having electron transport properties, and the other is a material having hole transport properties. A material having a conductive property is advantageous in forming an exciplex, and is therefore a preferred configuration. be.

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

[0218] Examples of materials having electron transport properties include bis(10-hydroxybenzo[h]quinoline). Beryllium(II) (BeBq2), bis(2-methyl-8-quinolinola Bis(8 -quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl )phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl )phenolato]zinc(II) (abbreviation: ZnBTZ), and (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 (abbreviated as 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'-(dibenzothiazol-2-yl) [4-(4-phenyl-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl] 2mCzBPDBq), 4, 6-bis[3-(phenanthrene-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 with a diazine skeleton and heterocyclic compounds with 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 a reduction in 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)-triphenyla PCBAN (abbreviation: PCBAN) -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 (abbreviated as 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 (abbreviated as PCCP), and ,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)(abbreviation Name: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoro

[0123] (9-phenyl-2-olen-9-yl)dibenzothiophene (abbreviation: DBTFLP-III), 4 -[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzyl compounds with a thiophene skeleton, such as dibenzothiophene (abbreviated as 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 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 facilitates the transport 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-difluoromethylphenyl) (2-phenyl-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 with 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-described configuration are 16d-2 can be deposited by co-evaporation in vacuum deposition, or by inkjet or spin coating as a mixed solution. The film 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-transparent electrode. The reflective electrode and the semi-transmissive / semi-reflective electrode are 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 organic EL device also has an EL layer, and has at least a light-emitting layer that serves as a light-emitting region.

[0224] This configuration is used in a light-emitting device using blue fluorescence and yellow phosphorescence to obtain green light. It can be used particularly effectively.

[0225] In a light-emitting device using blue fluorescence and yellow phosphorescence according to one embodiment of the present invention, green light is obtained. To achieve this, it is necessary to convert the blue fluorescence into green light using 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 amplify the blue light emission and attenuate the yellow light emission using a resonant structure. This is a preferable configuration because the energy loss is relatively small.

[0226] The light emitted in all directions from the light-emitting layer contained in the EL layer is reflected by the reflective electrode and the semi-transparent and semi-reflective electrode. The reflecting electrode 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 semi-permeable. The semi-reflective electrode is made of a conductive material that is reflective and light-transmitting. The reflectance of visible light to the outside is 20% to 80%, preferably 40% to 70%, and The resistivity of -2 It is assumed that the film has a resistance of Ωcm or less.

[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 / semi-reflective electrode, Between the reflective electrode and the semi-transparent / 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 that is reflected by the reflective electrode and returned (first reflected light) is This causes significant interference with the light (first incident light) that directly enters 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 distance 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 can be done.

[0229] In the above configuration, even if the EL layer has a plurality of light-emitting layers, a single light-emitting layer For example, it may be combined with the configuration of the tandem light emitting device described above. In addition, a plurality of EL layers are provided in one light-emitting element with a charge generating layer sandwiched therebetween, 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] The microcavity structure enhances the front-facing light intensity of specific wavelengths. This makes it possible to reduce power consumption. The light-emitting element using a (phenylamino)pyrene derivative as a luminescent center material emits light from the derivative. The emission spectrum has a narrow half-width and a sharp spectral shape, which indicates that it is The use of a cavity structure has a large effect on light emission amplification, resulting in very good light emission efficiency. A light emitting element having such properties 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. 6. 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 shown by the dotted line that 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, and 605 is a sealing material. 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, this 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 portion, is formed in this example. , 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. In addition, the drive circuit is a CMOS circuit Alternatively, the substrate may be formed of a PMOS circuit or an NMOS circuit. Although the driver integrated type with the drive circuit formed on the top is shown, 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 by 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 that combines three or more FETs and a capacitance element may be used. Good too.

[0236] There are no particular restrictions on the type and crystallinity of the semiconductor used in the FET, and amorphous semiconductors are used. Examples of semiconductors used in FETs include the first Group 3 (gallium, etc.) semiconductors, Group 14 (silicon, etc.) semiconductors, compound semiconductors, oxide semiconductors Although organic semiconductor materials can be used, it is particularly preferable to use oxide semiconductors. Examples of oxide semiconductors include In-Ga oxide and In-M-Zn oxide (M is Al). , Ga, Y, Zr, La, Ce, or Nd). An oxide semiconductor having 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, which is preferable. 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 at the top end of the insulator 614. It is preferable to provide a curved surface having a curved surface. Alternatively, a positive photosensitive resin can 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 with reference to FIGS. 5(A) to 5(C), respectively. (or the EL layer 103d or the EL layer 103a) and the second electrode 104.

[0240] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealing material 605, A space 607 surrounded by an element substrate 610, a sealing substrate 604, and a sealing material 605 contains a light-emitting element. 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 influence of moisture. This is a preferable configuration because it can suppress deterioration due to the temperature change.

[0241] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials be 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) A plastic substrate made of, for example, polyester or acrylic can be used.

[0242] For example, in this specification and the like, transistors and light-emitting elements are formed using various substrates. The type of substrate is not limited to a specific one. An example of the substrate is as follows: Examples include semiconductor substrates (such as 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 dioxide. Examples include glass-lime glass. Flexible substrates, laminated films, and base films. Examples include: polyethylene terephthalate (PET) , polyethylene naphthalate (PEN), and polyethersulfone (PES). For example, there are plastics such as acrylic resins. Examples of the material include polypropylene, polyester, polyvinyl fluoride, and polyvinyl chloride. Also available are polyamide, polyimide, aramid, epoxy, inorganic vapor 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 with high current capability and small size. When a circuit is constructed using transistors, the power consumption of the circuit can be reduced or 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 the semiconductor device is partially or entirely completed thereon. The transistor can be separated and transferred to another substrate. The transfer can be performed on a substrate having poor mechanical strength 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 a separate substrate. An example of a substrate onto which a transistor or a light-emitting element is transferred is a substrate on which the above-described 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, linen), synthetic fibers ( nylon, polyurethane, polyester) or regenerated fiber (acetate, cupra, These include polyester (including 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 star, make 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 this embodiment. In FIG. 7A, a substrate 1001, an insulating base film 1002, gate insulating film 1003, gate electrodes 1006, 1007, 1008, 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. It is assumed that the light emitted is a combination of blue fluorescent light and yellow phosphorescent light, but Not limited to.

[0246] In addition, in FIG. 7(A), there are red color conversion layer 1034R, green color conversion layer 1034G, and 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 also be provided. The transparent substrate 1033 on which the filter layer, color conversion layer, and black layer are provided is aligned and The color filter layer, color conversion layer, and 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 between the gate insulating film 1003 and the 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 from the substrate 1001 side 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. It may also be a light emitting device with a structure where light is extracted (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 also serve as a planarizing layer. The insulating film 1037 is formed using the same material as the second interlayer insulating film, as well as various other materials. It is possible.

[0249] The first electrodes 1024Y, 1024R, 1024G, and 1024B of the light-emitting element are positive electrodes. The cathode is also used as the top-emission type light-emitting diode, as shown in Figure 8. In the case of a device, it is preferable that the first electrode is a reflective electrode. , which are described as the EL layer 103, the EL layer 103d, and the EL layer 103a in FIGS. 5(A) to 5(C). The device has such a configuration and is structured to obtain white light emission.

[0250] In the top emission structure shown in Figure 8, a color conversion layer and a color filter layer are provided. Sealing can be performed with a substrate 1031. The sealing substrate 1031 has a structure in which a pixel is positioned between pixels. A black layer (black matrix) 1035 may be provided so as to prevent the color filter layer from being damaged. 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] 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, a full color display may be performed using three colors of red, green, and blue, or four colors of 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 XY in 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 wall layer 954 is provided on the upper surface. The sidewall of the partition wall layer 954 becomes thinner as it approaches the substrate surface. The distance between one side wall and the other side wall is gradually narrowed. The cross section of the wall layer 954 in the short side direction is trapezoidal, and the bottom side (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 can be controlled by the FET formed in the This light emitting device can be suitably used as a device.

[0254] ≪Electronic equipment≫ Examples of electronic devices according to one embodiment of the present invention will be described. video equipment (also called televisions or television receivers), computers, etc. Digital cameras, digital video cameras, digital photo frames, mobile phones ( Mobile phones, also known as mobile phone devices, portable game machines, portable information terminals, sound reproducing devices, Examples 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. The display unit 7103 displays images. The display portion 7103 is configured by arranging light-emitting elements in a matrix.

[0256] The television device can be operated using an operation switch provided on the housing 7101 or a separate remote control. This can be done by the operation key 710 provided on the remote control operation device 7110. 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 information output from the computer may be provided.

[0257] The television device is configured to include a receiver, a modem, etc. It can receive general television broadcasts and can also transmit via wired or wireless communication via a modem. By connecting to a communication network, it can be transmitted in one direction (sender to receiver) or two directions (transmit It is also possible to communicate information between a sender and a receiver, or between receivers themselves.

[0258] FIG. 10(B1) shows a computer, which includes a main body 7201, a housing 7202, and a display portion 7203. , a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer has light-emitting elements arranged in a matrix on the display portion 7203. The computer shown in Figure 10(B1) is created by using the The computer in FIG. 10(B2) has a keyboard 7204, a pointing device, and a keyboard. 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. Two screens are connected by a hinge. This can cause problems such as scratches or damage to the screen when storing or transporting the device. It can be prevented.

[0259] 10(C) and 10(D) 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, there are operation buttons 7403 and an external connection port 7404 , a speaker 7405, a microphone 7406, etc. The display unit 7402 has a display area 7402 in which pixels are arranged in a matrix.

[0260] In the portable information terminal shown in FIGS. 10C and 10D, when the display portion 7402 is touched with a finger or the like, It may also be possible to input information. In this case, the information may be input by making a call or Operations such as creating an email 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, and the second mode is an input mode that mainly inputs information such as characters. This is a display + input mode that combines the display mode and the input mode.

[0262] For example, when making a call or creating an email, the display portion 7402 is used for inputting characters. In this case, you can input characters displayed on the screen. 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 that detects tilt, such as a gyro or acceleration sensor. By providing a detection device for detecting the orientation of the mobile information terminal (portrait or landscape), the display unit 740 2 screen display can be automatically switched.

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

[0265] In the input mode, a signal detected by the optical sensor of the display unit 7402 is detected and displayed. 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 normal mode to the display mode.

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

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

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

[0269] An automobile according to one embodiment of the present invention is shown in Figure 11. The automobile has a windshield and a dash panel. The display area 5000 to the display area 5005 are light-emitting elements. The organic compound according to one embodiment of the present invention is preferably used. Moreover, by using the organic compound, a light-emitting element with low power consumption can be obtained. This also reduces power consumption in the display areas 5000 to 5005. , and is suitable for use in vehicles.

[0270] The display area 5000 and the display area 5001 are light-emitting devices provided on the windshield of the automobile. The light-emitting element is a display device using a first electrode and a second electrode. By using electrodes that can be seen through to the other side, a so-called see-through display can be achieved. If the display is see-through, it can be installed on the windshield of a car. Even if the device is placed in a location, it can be installed without obstructing the view. When a transistor is provided, an organic transistor made of an organic semiconductor material or an oxide 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 Similarly, it can complement the view obstructed by the The display area 5003 is a 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 surrounding area, blind spots can be filled and safety can be improved. By projecting images that complement the unseen 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 a variety of information, including distance, fuel level, gear status, and air conditioning settings. 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 mobile information terminal 9310. 12(A) shows the mobile information terminal 9310 in an unfolded state. indicates a mobile information terminal 9310 in a state in which it is changing from one folded state to the other. FIG. 12C shows the portable information terminal 9310 in a folded state. The 0 offers excellent portability when folded and a seamless, large 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 hinge 9313 allows the two housings 9315 to bend, making it portable. The information terminal 9310 can be reversibly transformed from an unfolded state to a folded state. The light-emitting device of one embodiment of the present invention can be used for the display panel 9311. The display area 9312 in the 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 check information and shortcuts to apps, etc. It can be started up smoothly.

[0275] In the above manner, an electronic device can be obtained by applying 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 this embodiment, but can be applied to electronic devices in any field. The present invention can be applied to the following electronic devices.

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

[0277] 100 boards 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 Third EL layer 103h 4th EL layer 103i First 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 Insulators 616 EL layer 617 Second electrode 618 Light-emitting element 623 n-channel FET 624 p-channel FET 625 Dry material 951 PCB 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 Housing 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 Housing 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 9310 Mobile Information Terminal 9311 Display Panel 9312 Display area 9313 Hinge 9315 Housing

Claims

1. A top-emission light-emitting device having a first substrate, a second substrate, a first light-emitting element, a second light-emitting element, a third light-emitting element, a first color filter, a first color conversion layer, a second color conversion layer, and a resin layer between the first substrate and the second substrate, Each of the first light-emitting element, the second light-emitting element, and the third light-emitting element is an anode; a first light-emitting layer above the anode, the first light-emitting layer including a light-emitting material that emits blue fluorescence; a charge generating layer above the first light emitting layer; a second light-emitting layer above the charge generating layer, the second light-emitting layer comprising a green phosphorescent light-emitting material; a cathode above the second light-emitting layer; The first to third light-emitting elements emit light in which blue and green are combined, the first light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the first light-emitting element and the first color filter, the first color filter is located between the resin layer and the second substrate; the second light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the second light-emitting element and the first color conversion layer, the first color conversion layer is located between the resin layer and the second substrate, the third light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the third light-emitting element and the second color conversion layer, the second color conversion layer is located between the resin layer and the second substrate, the first light-emitting element overlaps the first color filter; the second light-emitting element overlaps the first color conversion layer, the third light-emitting element overlaps the second color conversion layer, the first color filter transmits blue light; the first color conversion layer contains a color conversion material that emits green light, a light-emitting device, wherein the second color conversion layer contains a color conversion material that emits red light;

2. A top-emission light-emitting device having a first substrate, a second substrate, a first light-emitting element, a second light-emitting element, a third light-emitting element, a first color filter, a first color conversion layer, a second color conversion layer, and a resin layer between the first substrate and the second substrate, Each of the first light-emitting element, the second light-emitting element, and the third light-emitting element is an anode; a first light-emitting layer above the anode, the first light-emitting layer including a light-emitting material that emits blue fluorescence; a charge generating layer above the first light emitting layer; a second light-emitting layer above the charge generating layer, the second light-emitting layer comprising a green phosphorescent light-emitting material; a cathode above the second light-emitting layer; The first to third light-emitting elements emit light in which blue and green are combined, the first light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the first light-emitting element and the first color filter, the first color filter is located between the resin layer and the second substrate; the second light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the second light-emitting element and the first color conversion layer, the first color conversion layer is located between the resin layer and the second substrate, the third light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the third light-emitting element and the second color conversion layer, the second color conversion layer is located between the resin layer and the second substrate, the first light-emitting element overlaps the first color filter; the second light-emitting element overlaps the first color conversion layer, the third light-emitting element overlaps the second color conversion layer, the first color filter transmits blue light; the first color conversion layer contains a color conversion material that emits green light, the second color conversion layer contains a color conversion material that emits red light, The light emitting device, wherein the second substrate is a glass substrate.

3. A top-emission light-emitting device having a first substrate, a second substrate, a first light-emitting element, a second light-emitting element, a third light-emitting element, a first color filter, a first color conversion layer, a second color conversion layer, a resin layer, and an overcoat layer between the first substrate and the second substrate, Each of the first light-emitting element, the second light-emitting element, and the third light-emitting element is an anode; a first light-emitting layer above the anode, the first light-emitting layer including a light-emitting material that emits blue fluorescence; a charge generating layer above the first light emitting layer; a second light-emitting layer above the charge generating layer, the second light-emitting layer comprising a green phosphorescent light-emitting material; a cathode above the second light-emitting layer; The first to third light-emitting elements emit light in which blue and green are combined, the first light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the first light-emitting element and the first color filter, the first color filter is located between the resin layer and the second substrate; the second light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the second light-emitting element and the first color conversion layer, the first color conversion layer is located between the resin layer and the second substrate, the third light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the third light-emitting element and the second color conversion layer, the second color conversion layer is located between the resin layer and the second substrate, the first light-emitting element overlaps the first color filter; the second light-emitting element overlaps the first color conversion layer, the third light-emitting element overlaps the second color conversion layer, the first color filter transmits blue light; the first color conversion layer contains a color conversion material that emits green light, the second color conversion layer contains a color conversion material that emits red light, The light-emitting device, wherein the overcoat layer overlaps the first color filter, the first color conversion layer, and the second color conversion layer.

4. A top-emission light-emitting device having a first substrate, a second substrate, a first light-emitting element, a second light-emitting element, a third light-emitting element, a first color filter, a first color conversion layer, a second color conversion layer, a resin layer, and an overcoat layer between the first substrate and the second substrate, Each of the first light-emitting element, the second light-emitting element, and the third light-emitting element is an anode; a first light-emitting layer above the anode, the first light-emitting layer including a light-emitting material that emits blue fluorescence; a charge generating layer above the first light emitting layer; a second light-emitting layer above the charge generating layer, the second light-emitting layer comprising a green phosphorescent light-emitting material; a cathode above the second light-emitting layer; The first to third light-emitting elements emit light in which blue and green are combined, the first light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the first light-emitting element and the first color filter, the first color filter is located between the resin layer and the second substrate; the second light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the second light-emitting element and the first color conversion layer, the first color conversion layer is located between the resin layer and the second substrate, the third light-emitting element is located between the first substrate and the resin layer, the resin layer is located between the third light-emitting element and the second color conversion layer, the second color conversion layer is located between the resin layer and the second substrate, the first light-emitting element overlaps the first color filter; the second light-emitting element overlaps the first color conversion layer, the third light-emitting element overlaps the second color conversion layer, the first color filter transmits blue light; the first color conversion layer contains a color conversion material that emits green light, the second color conversion layer contains a color conversion material that emits red light, the second substrate is a glass substrate, The light-emitting device, wherein the overcoat layer overlaps the first color filter, the first color conversion layer, and the second color conversion layer.

5. In any one of claims 1 to 4, the first color conversion layer does not have a region in contact with the first color filter in a cross-sectional view; a light-emitting device, wherein the second color conversion layer does not have a region in contact with the first color filter in a cross-sectional view;

6. In any one of claims 1 to 5, The light-emitting device, wherein the first color conversion layer and the second color conversion layer are color conversion layers using quantum dots.

7. In any one of claims 1 to 6, The light emitting device, wherein the first light emitting element and the first color conversion layer do not overlap each other.

8. In any one of claims 1 to 7, the second light-emitting layer includes a first organic compound and a second organic compound; The first organic compound and the second organic compound form an exciplex.

9. In claim 8, a light-emitting device, wherein an emission spectrum of the exciplex overlaps with an absorption band on the longest wavelength side of an absorption spectrum of the light-emitting material that emits green phosphorescence;

10. In any one of claims 1 to 9, Further, the transistor includes an oxide semiconductor, the transistor is electrically connected to the anode.

11. A light emitting device according to any one of claims 1 to 10; An electronic device including at least one of a sensor, an operation button, a speaker, and a microphone.

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