JP2015130319A - Light-emitting element, light-emitting device, electronic equipment, and illuminating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting element with a high light emission efficiency capable of exhibiting light with a high chromatic purity by a microcavity effect as each of monochromatic lights, and of obtaining white light emission exhibiting broad spectrum when a plurality of these monochromatic lights are combined.SOLUTION: A light-emitting element has a plurality of EL layers between a pair of electrodes. By utilizing a microcavity effect to a plurality of luminous colors obtained from the respective EL layers, a plurality of monochromatic lights can be efficiency extracted, and light obtained by combining a plurality of light emissions obtained from the respective EL layers is white light (hereinafter, referred to as standard white light) within a range prescribed as white light of indoor illumination in Japan Industrial Standards (JIS standard)(in concrete terms, a correlation color temperature is 2600 K or more and 7100 K or less).

Description

One embodiment of the present invention relates to a light-emitting element in which an organic compound that can emit light by applying an electric field is sandwiched between a pair of electrodes, and a light-emitting device, an electronic device, and a lighting device each having such a light-emitting element.

Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, a manufacture, or a composition (composition of matter). Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically includes a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, a driving method thereof, Alternatively, the production method thereof can be given as an example.

A light-emitting element using an organic compound having characteristics such as thin and light weight, high-speed response, and direct current low-voltage driving as a light emitter is expected to be applied to a next-generation flat panel display. In particular, a display device in which light emitting elements are arranged in a matrix is considered to be superior to a conventional liquid crystal display device in that it has a wide viewing angle and excellent visibility.

The light-emitting mechanism of the light-emitting element is that when an EL layer containing a light-emitting substance is sandwiched between a pair of electrodes and a voltage is applied, electrons injected from the cathode and holes injected from the anode are recombined in the EL layer. It is said that when a molecular exciton is formed and the molecular exciton relaxes to the ground state, it emits energy and emits light. Singlet excitation and triplet excitation are known as excited states, and light emission is considered to be possible through either excited state.

With respect to such a light emitting element, development has been carried out so that various emission colors can be obtained by improving the element structure or developing materials. When obtaining monochromatic light, the color purity is increased by narrowing the spectrum using the microcavity effect. However, the situation is different for white light used for indoor lighting. For example, in the Japanese Industrial Standard (JIS standard), white light for indoor lighting is defined by a correlated color temperature, and the range is set to 2600K to 7100K. Since the light represented by such a color temperature is a light exhibiting a broad emission spectrum, it is very difficult to obtain light satisfying the above standards using monochromatic light. Therefore, development is progressing to obtain desired light by combining a plurality of lights (see, for example, Patent Document 1).

JP 2007-53090 A

In one embodiment of the present invention, the monochromatic light exhibits high color purity light due to the microcavity effect, and when combining a plurality of these lights, the light emission with high light emission efficiency that produces white light emission having a broad spectrum is obtained. An element is provided. In one embodiment of the present invention, a light-emitting device that can realize low power consumption using the light-emitting element is provided. Furthermore, one embodiment of the present invention provides an electronic device and a lighting device that can achieve low power consumption. Another embodiment of the present invention provides a novel light-emitting element, a novel light-emitting device, a novel lighting device, or the like. Note that the description of these problems does not disturb the existence of other problems. Note that one embodiment of the present invention does not necessarily have to solve all of these problems. Issues other than these will be apparent from the description of the specification, drawings, claims, etc., and other issues can be extracted from the descriptions of the specification, drawings, claims, etc. It is.

One embodiment of the present invention has a plurality of EL layers between a pair of electrodes, and efficiently extracts a plurality of monochromatic lights by using the microcavity effect for a plurality of light-emitting colors obtained from the EL layers. In addition, the light obtained by combining a plurality of light emission obtained from each EL layer is a range defined as white light for indoor lighting in the Japanese Industrial Standard (JIS standard) (specifically, correlated color temperature Is a white light (hereinafter, referred to as standard white light) at 2600K to 7100K).

Specifically, a plurality of EL layers are provided between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and each of the plurality of EL layers has a tandem structure with a charge generation layer interposed therebetween. In the light emitting element, in addition to the element structure having the microcavity effect, the light emitting region of the EL layer closest to the semi-transmissive / semi-reflective electrode and the optical distance to the semi-transmissive / semi-reflective electrode are set to be less than λ / 4. This is a light-emitting element that can make monochromatic light obtained from a plurality of EL layers narrower while making the combined light into standard white light.

Therefore, one embodiment of the present invention includes a plurality of EL layers between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and the plurality of EL layers are stacked with a charge generation layer interposed therebetween. Among the plurality of EL layers, the optical distance from the light emitting region of the EL layer closest to the semi-transmissive / semi-reflective electrode to the semi-transmissive / semi-reflective electrode is less than λ / 4.

Another embodiment of the present invention includes two EL layers between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and the two EL layers are stacked with a charge generation layer interposed therebetween. Of the two EL layers, the EL layer on the semi-transmissive / semi-reflective electrode side has two stacked light-emitting layers, and the optical distance from the semi-transmissive / semi-reflective electrode to the stack interface of the two light-emitting layers Is a light emitting element characterized by being less than λ / 4.

Another embodiment of the present invention includes two EL layers between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and the two EL layers are stacked with a charge generation layer interposed therebetween. Of the two EL layers, the EL layer on the semi-transmissive / semi-reflective electrode side has two stacked light-emitting layers, and the two light-emitting layers each emit phosphorescent light having different emission colors and are semi-transmissive. The light emitting element is characterized in that the optical distance from the semi-reflective electrode to the interface between the two light emitting layers is less than λ / 4.

Another embodiment of the present invention includes two EL layers between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and the two EL layers are stacked with a charge generation layer interposed therebetween. Of the two EL layers, one EL layer on the reflective electrode side has a light emitting layer that emits fluorescence, and the other EL layer has two stacked light emitting layers. Is a light-emitting element that exhibits phosphorescence having different emission colors, and that the optical distance from the semi-transmissive / semi-reflective electrode to the stack interface of the two light-emitting layers is less than λ / 4.

Another embodiment of the present invention includes two EL layers between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and the two EL layers are stacked with a charge generation layer interposed therebetween. Of the two EL layers, one EL layer on the reflective electrode side has a light emitting layer that emits blue light, and the other EL layer emits red light on the light emitting layer that emits green light sequentially from the reflective electrode side. The optical distance from the semi-transmissive / semi-reflective electrode to the interface between the green light emitting layer and the red light emitting layer is less than λ / 4. It is a light emitting element characterized by these.

Another embodiment of the present invention includes two EL layers between a pair of electrodes including a reflective electrode and a semi-transmissive / semi-reflective electrode, and the two EL layers are stacked with a charge generation layer interposed therebetween. Of the two EL layers, one EL layer on the reflective electrode side has a light emitting layer that emits blue fluorescent light, and the other EL layer has a light emitting layer that emits green phosphorescent light in order from the reflective electrode side; It has a structure in which a light emitting layer exhibiting red phosphorescence is laminated, and the optical distance from the semi-transmissive / semi-reflective electrode to the interface between the light emitting layer exhibiting green phosphorescence and the light emitting layer exhibiting red phosphorescence is λ It is a light emitting element characterized by being less than / 4.

Further, one embodiment of the present invention includes in its category a light-emitting device including the light-emitting element described in each of the above structures, and an electronic device and a lighting device each including the light-emitting device. Therefore, a light-emitting device in this specification refers to an image display device, a light-emitting device, or a light source (including a lighting device). Also, a connector such as a flexible printed circuit (FPC) or TCP (Tape Carrier Package) attached to the light emitting device, a module provided with a printed wiring board at the end of the TCP, or a COG (Chip On Glass) attached to the light emitting element. A module on which an IC (integrated circuit) is directly mounted by a method may include a light emitting device.

According to one embodiment of the present invention, as monochromatic light, light having high color purity due to the microcavity effect is displayed, and when combining a plurality of these lights, light emission with high light emission efficiency that produces white light emission having a broad spectrum is obtained. An element can be provided. According to one embodiment of the present invention, a light-emitting device that can achieve low power consumption using the light-emitting element can be provided. Furthermore, according to one embodiment of the present invention, an electronic device and a lighting device that can achieve low power consumption can be provided. Alternatively, according to one embodiment of the present invention, a novel light-emitting element, a novel light-emitting device, a novel lighting device, or the like can be provided. Note that the description of these effects does not disturb the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. It should be noted that the effects other than these are naturally obvious from the description of the specification, drawings, claims, etc., and it is possible to extract the other effects from the descriptions of the specification, drawings, claims, etc. It is.

4A and 4B illustrate a structure of a light-emitting element. FIG. 10 illustrates a structure of a pixel portion of a light-emitting device. FIG. 6 illustrates a light-emitting device. 6A and 6B illustrate electronic devices. The figure explaining an illuminating device. 3A and 3B each illustrate a structure of a light-emitting element shown in Example 1. FIG. 9 shows luminance-current efficiency characteristics of the light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4. FIG. 6 shows chromaticity characteristics of the light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4. FIG. 6 shows emission spectra of the light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4. An external view of the RGBW flexible display with a top roll structure.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes can be made in form and details without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

(Embodiment 1)
In this embodiment, a light-emitting element which is one embodiment of the present invention will be described.

A light-emitting element which is one embodiment of the present invention is formed by sandwiching a plurality of EL layers including a light-emitting layer between a pair of electrodes, and the plurality of EL layers are stacked with a charge generation layer interposed therebetween (tandem structure) Have Hereinafter, a light-emitting element having a tandem structure including two EL layers as an element structure of a light-emitting element which is one embodiment of the present invention will be described with reference to FIGS.

In the light-emitting element shown in FIG. 1, two EL layers (103a and 103b) including a light-emitting layer are sandwiched between a pair of electrodes (first electrode 101 and second electrode 102), and each EL layer (103a , 103b) from the anode 101 side, hole injection layer (104a, 104b), hole transport layer (105a, 105b), light emitting layer (106a, 106b), electron transport layer (107a, 107b). ), An electron injection layer (108a, 108b) and the like are sequentially stacked. In addition, a charge generation layer 109 is provided between the EL layer 103a and the EL layer 103b.

Each of the light-emitting layers (106a and 106b) contains a light-emitting substance and a plurality of substances in appropriate combination, and can have a structure in which fluorescence or phosphorescence exhibiting a desired emission color can be obtained. Alternatively, as illustrated in the light-emitting layer 106b, a stacked structure in which light-emitting layers (106 (b1) and 106 (b2)) containing different light-emitting substances are stacked can be employed.

The charge generation layer 109 injects electrons into one EL layer (103a or 103b) when a voltage is applied to the first electrode 101 and the second electrode 102, and the other EL layer (103b or 103a). ) Has a function of injecting holes. Therefore, in FIG. 1, when a voltage is applied to the first electrode 101 so that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 109 into the EL layer 103a and holes are injected into the EL layer 103b. Will be injected.

Note that the charge generation layer 109 has a property of transmitting visible light from the viewpoint of light extraction efficiency (specifically, the visible light transmittance of the charge generation layer 109 is 40% or more). preferable. In addition, the charge generation layer 109 functions even when it has lower conductivity than the first electrode 101 or the second electrode 102.

In the light-emitting element shown in FIG. 1, light emitted from each light-emitting layer (106 (b1), 106 (b2)) included in each EL layer (103a, 103b) in all directions is emitted from a micro optical resonator ( The first electrode (reflective electrode) 101 having a function as a microcavity and the second electrode (semi-transmissive / semi-reflective electrode) resonate. Then, it is emitted from the second electrode 102 side. Note that the first electrode 101 is a reflective electrode, and has a laminated structure of a conductive material having reflectivity and a transparent conductive film, and optical adjustment is performed by controlling the film thickness of the transparent conductive film. Yes. In some cases, optical adjustment can be performed by controlling the film thickness of the hole injection layer 104a included in the EL layer 103a.

In this manner, the light emitting layers (106a, 106b (106 (b1), 106 (b2)) are controlled by controlling the film thickness of the first electrode 101 and the hole injection layer 104a to perform optical adjustment. The spectrum of a plurality of monochromatic lights obtained from (1) can be narrowed, and light emission with good color purity can be obtained.

In the light-emitting element shown in FIG. 1, the optical distance between the light-emitting region in the EL layer 103b closest to the second electrode 102 functioning as a semi-transmissive / semi-reflective electrode and the second electrode 102 is light emission in the light-emitting region. It is formed to be less than λ / 4 with respect to the wavelength of the light to be transmitted. Note that the light emitting region herein refers to a recombination region between holes and electrons, but it is necessary to consider that the position differs depending on the carrier balance in the light emitting layer. In addition, in the case where the light emitting layer 106b includes the light emitting layer 106 (b1) and the light emitting layer 103 (b2) that include different light emitting substances and exhibit different light emission, the light emitting region is in the vicinity of the stack interface. Suppose there is. In this manner, by forming the light emitting region in the EL layer 103b closest to the second electrode 102 so that the optical distance between the second electrode 102 is less than λ / 4, the light emitting element shown in FIG. Standard white light can be obtained from light emission obtained by combining a plurality of monochromatic lights obtained from the respective light emitting layers (106a, 106b (106 (b1), 106 (b2))).

Next, specific examples for manufacturing the above light-emitting element will be described.

Since the first electrode 101 is a reflective electrode, it is formed of a conductive material having reflectivity, and the reflectance of visible light with respect to the film is 40% to 100%, preferably 70% to 100%. In addition, it is assumed that the film has a resistivity of 1 × 10 ⁻² Ωcm or less. The semi-transmissive / semi-reflective electrode 302 is formed of a conductive material having reflectivity and a conductive material having light transmittance, and the reflectance of visible light to the film is 20% or more and 80% or less, preferably It is assumed that the film is 40% or more and 70% or less and has a resistivity of 1 × 10 ⁻² Ωcm or less.

Further, among the light from each light emitting layer (106 (b1), 106 (b2)), the extracted light is resonated and the wavelength of the first electrode 101 and the second electrode can be increased for each wavelength. The optical distance from the electrode 102 is adjusted. Specifically, the film thickness of the transparent conductive film used for a part of the first electrode 101 is changed so that the distance between the electrodes becomes mλ / 2 (where m is a natural number) with respect to the wavelength λ of the extracted light. Adjust to.

Further, in order to amplify the extracted light out of the light from each of the light emitting layers (106 (b1) and 106 (b2)), the optical distance between the first electrode 101 and the light emitting layer that emits the extracted light is adjusted. To do. Specifically, the thickness of the transparent conductive film used for part of the first electrode 101 or the organic film forming the hole injection layer 104a is changed, and the optical distance with respect to the wavelength λ of the extracted light. Is adjusted to be (2m ′ + 1) λ / 4 (where m ′ is a natural number).

Note that in the above case, the optical distance between the first electrode 101 and the second electrode 102 is strictly the total thickness from the reflective region of the first electrode 101 to the reflective region of the second electrode 102. it can. However, since it is difficult to precisely determine the position of the reflection region in the first electrode 101 or the second electrode 102, any position of the first electrode 101 and the second electrode 102 is assumed to be the reflection region. By doing so, the above-described effects can be sufficiently obtained. In addition, the optical distance between the first electrode 101 and the light-emitting layer that emits light to be extracted is strictly the optical distance between the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer that emits light to be extracted. be able to. However, since it is difficult to strictly determine the position of the light-emitting region in the light-emitting layer that emits the light to be extracted and the reflection region in the first electrode 101, the light from which an arbitrary position of the first electrode 101 is extracted in the reflection region It is assumed that the above-described effects can be sufficiently obtained by assuming an arbitrary position of the light emitting layer that emits light as a light emitting region.

Note that as a material for forming the first electrode 101 and the second electrode 102 that satisfy the above conditions, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like can be used as appropriate. Specifically, indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc-oxide (Indium Zinc Oxide), tungsten oxide and zinc oxide were contained. Indium oxide, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium ( In addition to Pd) and titanium (Ti), elements belonging to Group 1 or Group 2 of the periodic table of elements, that is, alkali metals such as lithium (Li) and cesium (Cs), and calcium (Ca) and strontium (Sr) Alkaline earth metals such as magnesium (Mg), and alloys containing these (MgAg, LLI), europium (Eu), ytterbium (Yb), an alloy containing these can be used, such as other graphene like. Note that the first electrode 101 and the second electrode 102 can be formed by, for example, a sputtering method, an evaporation method (including a vacuum evaporation method), or the like.

The hole injection layer (104a, 104b) is a layer that injects holes into the light emitting layer (106a, 106b) through the hole transport layer (105a, 105b) having a high hole transport property, and has a hole transport property. A layer containing a material and an acceptor substance. By including the hole transporting material and the acceptor substance, electrons are extracted from the hole transporting material by the acceptor substance to generate holes, and the holes are transported through the hole transport layers (105a and 105b). Holes are injected into the light emitting layers (106a, 106b). Note that the hole transport layers (105a and 105b) are formed using a hole transport material.

As a hole transporting material used for the hole injection layer (104a, 104b) and the hole transport layer (105a, 105b), for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino ] Biphenyl (abbreviation: NPB or α-NPD) and N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviation: TPD), 4,4 ′, 4 ″ -tris (carbazol-9-yl) triphenylamine (abbreviation: TCTA), 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- R) -N-phenylamino] biphenyl (abbreviation: BSPB) and the like, 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3- [N- (1-naphthyl) -N -(9-phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) and the like. In addition, 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB), 9- [4- ( Carbazole derivatives such as 10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), and the like can be used. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used.

Further, poly (N-vinylcarbazole) (abbreviation: PVK), poly (4-vinyltriphenylamine) (abbreviation: PVTPA), poly [N- (4- {N ′-[4- (4-diphenylamino)] Phenyl] phenyl-N′-phenylamino} phenyl) methacrylamide] (abbreviation: PTPDMA) poly [N, N′-bis (4-butylphenyl) -N, N′-bis (phenyl) benzidine] (abbreviation: Poly High molecular compounds such as -TPD) can also be used.

Examples of the acceptor substance used for the hole injection layer (105a, 105b) include oxides of metals belonging to Groups 4 to 8 in the periodic table. Specifically, molybdenum oxide is particularly preferable.

The light-emitting layers (106a and 106b (106 (b1) and 106 (b2))) are layers containing a light-emitting substance. Note that the light-emitting layer (106a, 106b (106 (b1), 106 (b2))) includes one or both of an electron transporting material and a hole transporting material in addition to the light-emitting substance. .

Note that there is no particular limitation on a material that can be used as the light-emitting substance in the light-emitting layers (106a and 106b (106 (b1) and 106 (b2))), and the light-emitting property that changes singlet excitation energy into light emission is not particularly limited. A material or a luminescent material that changes triplet excitation energy into light emission can be used. Examples of the luminescent substance include the following.

Examples of the light-emitting substance that converts singlet excitation energy into light emission include substances that emit fluorescence. For example, N, N′-bis [4- (9H-carbazol-9-yl) phenyl] -N, N′- Diphenylstilbene-4,4′-diamine (abbreviation: YGA2S), 4- (9H-carbazol-9-yl) -4 ′-(10-phenyl-9-anthryl) triphenylamine (abbreviation: YGAPA), 4- (9H-carbazol-9-yl) -4 ′-(9,10-diphenyl-2-anthryl) triphenylamine (abbreviation: 2YGAPPA), N, 9-diphenyl-N- [4- (10-phenyl-9 -Anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation) TBP), 4- (10-phenyl-9-anthryl) -4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBAPA), N, N ″-(2-tert -Butylanthracene-9,10-diyldi-4,1-phenylene) bis [N, N ', N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N, 9-diphenyl-N- [4- (9,10-diphenyl-2-anthryl) phenyl] -9H-carbazol-3-amine (abbreviation: 2PCAPPA), N- [4- (9,10-diphenyl-2-anthryl) phenyl] -N , N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N, N, N ′, N ′, N ″, N ″, N ′ ″, N ′ ″ − Octa Enyldibenzo [g, p] chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N- (9,10-diphenyl-2-anthryl) -N, 9-diphenyl-9H-carbazole- 3-Amine (abbreviation: 2PCAPA), N- [9,10-bis (1,1′-biphenyl-2-yl) -2-anthryl] -N, 9-diphenyl-9H-carbazol-3-amine (abbreviation) : 2PCABPhA), N- (9,10-diphenyl-2-anthryl) -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N- [9,10-bis ( 1,1′-biphenyl-2-yl) -2-anthryl] -N, N ′, N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10- Bis (1,1′-biphenyl-2-yl) -N- [4- (9H-carbazol-9-yl) phenyl] -N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N, N, 9 -Triphenylanthracen-9-amine (abbreviation: DPhAPhA), coumarin 545T, N, N'-diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12-bis (1,1'-biphenyl-4-yl) -6,11-diphenyltetracene (abbreviation: BPT), 2- (2- {2- [4- (dimethylamino) phenyl] ethenyl} -6-methyl-4H-pyran-4-ylidene) propanedinitrile (abbreviation) : DCM 1), 2- {2-methyl-6- [2- (2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) etheni ] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCM2), N, N, N ′, N′-tetrakis (4-methylphenyl) tetracene-5,11-diamine (abbreviation: p-mPhTD) 7,14-diphenyl-N, N, N ′, N′-tetrakis (4-methylphenyl) acenaphtho [1,2-a] fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2- { 2-Isopropyl-6- [2- (1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H- Pyran-4-ylidene} propanedinitrile (abbreviation: DCJTI), 2- {2-tert-butyl-6- [2- (1,1,7,7-tetramethyl-2,3,6,7-tetrahydro) -1 , 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: DCJTB), 2- (2,6-bis {2- [4- (dimethylamino) ) Phenyl] ethenyl} -4H-pyran-4-ylidene) propanedinitrile (abbreviation: BisDCM), 2- {2,6-bis [2- (8-methoxy-1,1,7,7-tetramethyl-) 2,3,6,7-tetrahydro-1H, 5H-benzo [ij] quinolizin-9-yl) ethenyl] -4H-pyran-4-ylidene} propanedinitrile (abbreviation: BisDCJTM), and the like.

Examples of the light-emitting substance that changes triplet excitation energy into light emission include a substance that emits phosphorescence and a thermally activated delayed fluorescence (TADF) material that exhibits thermally activated delayed fluorescence. Note that delayed fluorescence in a TADF material refers to light emission having a remarkably long lifetime while having a spectrum similar to that of normal fluorescence. The lifetime is 10 ⁻⁶ seconds or longer, preferably 10 ⁻³ seconds or longer.

As a substance that emits phosphorescence, bis [2- (3 ′, 5′-bistrifluoromethylphenyl) pyridinato-N, C ^{2 ′} ] iridium (III) picolinate (abbreviation: Ir (CF ₃ ppy) ₂ (pic)) Bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ^{2 ′} ] iridium (III) acetylacetonate (abbreviation: FIracac), tris (2-phenylpyridinato) iridium (III) ( Abbreviations: Ir (ppy) ₃ ), bis (2-phenylpyridinato) iridium (III) acetylacetonate (abbreviation: Ir (ppy) ₂ (acac)), tris (acetylacetonato) (monophenanthroline) terbium ( III) _{(abbreviation: Tb (acac) 3 (Phen} )), bis (benzo [h] quinolinato) iridium (I I) acetylacetonate _{(abbreviation: Ir (bzq) 2 (acac} )), bis (2,4-diphenyl-1,3 oxazolato -N, C ^{2 ')} iridium (III) acetylacetonate (abbreviation: Ir ( dpo) ₂ (acac)), bis {2- [4 ′-(perfluorophenyl) phenyl] pyridinato-N, C ^{2 ′} } iridium (III) acetylacetonate (abbreviation: Ir (p-PF-ph) ₂ (Acac)), bis (2-phenylbenzothiazolate-N, C ^{2 ′} ) iridium (III) acetylacetonate (abbreviation: Ir (bt) ₂ (acac)), bis [2- (2′-benzo [4,5-α] thienyl) pyridinato -N, C ^{3 ']} iridium (III) acetylacetonate _{(abbreviation: Ir (btp) 2 (acac} )), bis (1-phenylene Isokinorinato -N, C ^{2 ')} iridium (III) acetylacetonate _{(abbreviation: Ir (piq) 2 (acac} )), ( acetylacetonato) bis [2,3-bis (4-fluorophenyl) quinoxalinato] iridium ( III) (abbreviation: Ir (Fdpq) ₂ (acac)), (acetylacetonato) bis (3,5-dimethyl-2-phenylpyrazinato) iridium (III) (abbreviation: [Ir (mppr-Me) ₂ (Acac)]), (acetylacetonato) bis (5-isopropyl-3-methyl-2-phenylpyrazinato) iridium (III) (abbreviation: [Ir (mppr-iPr) ₂ (acac)]), ( acetylacetonato) bis (2,3,5-triphenylpyrazinato) iridium (III) (abbreviation: Ir _{(tppr) 2} acac)), bis (2,3,5-triphenylpyrazinato) (dipivaloylmethanato) iridium (III) _{(abbreviation: [Ir (tppr) 2 (} dpm)]), ( acetylacetonato) bis (6-tert-butyl-4-phenylpyrimidinato) iridium (III) (abbreviation: [Ir (tBupppm) ₂ (acac)]), (acetylacetonato) bis (4,6-diphenylpyrimidinato) iridium (III) (abbreviation: [Ir (dppm) ₂ (acac)]), 2,3,7,8,12,13,17,18-octaethyl-21H, 23H-porphyrin platinum (II) (abbreviation: PtOEP) , Tris (1,3-diphenyl-1,3-propanedionate) (monophenanthroline) europium (III) (abbreviation: Eu (DBM) ₃ (P hen)), tris [1- (2-thenoyl) -3,3,3-trifluoroacetonato] (monophenanthroline) europium (III) (abbreviation: Eu (TTA) ₃ (Phen)) and the like.

Examples of the TADF material include fullerene and derivatives thereof, acridine derivatives such as proflavine, and eosin. In addition, metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), and the like can be given. Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF ₂ (Proto IX)), a mesoporphyrin-tin fluoride complex (SnF ₂ (Meso IX)), and a hematoporphyrin-tin fluoride complex (SnF). ₂ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ₂ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF ₂ (OEP)), etioporphyrin-tin fluoride And a complex (SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ₂ OEP), and the like. Furthermore, π-electron rich complex such as 2-biphenyl-4,6-bis (12-phenylindolo [2,3-a] carbazol-11-yl) -1,3,5-triazine (PIC-TRZ) A heterocyclic compound having an aromatic ring and a π-electron deficient heteroaromatic ring can also be used. In addition, a substance in which a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded increases both the donor property of the π-electron rich heteroaromatic ring and the acceptor property of the π-electron deficient heteroaromatic ring. , Because the energy difference between S1 and T1 is small.

As the electron transporting material used for the light emitting layer (106a, 106b (106 (b1), 106 (b2))), a π-electron deficient heteroaromatic compound such as a nitrogen-containing heteroaromatic compound is preferable. -[3- (Dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 2mDBTPDBq-II), 2- [3 ′-(dibenzothiophen-4-yl) biphenyl-3-yl] dibenzo [F, h] quinoxaline (abbreviation: 2mDBTBPDBq-II), 2- [4- (3,6-diphenyl-9H-carbazol-9-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 2CzPDBq-III) , 7- [3- (Dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 7mDBTPDB -II), and 6- [3- (dibenzothiophen-4-yl) phenyl] dibenzo [f, h] quinoxaline (abbreviation: 6mDBTPDBq-II) quinoxaline or dibenzo quinoxaline derivatives, and the like.

In addition, as a hole transporting material used for the light emitting layer (106a, 106b (106 (b1), 106 (b2))), a π-electron rich heteroaromatic compound (for example, a carbazole derivative or an indole derivative) or an aromatic amine is used. The compound is preferable, for example, 4-phenyl-4 ′-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBA1BP), 4,4′-di (1-naphthyl) -4 ″ -(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB), 3- [N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9 -Phenylcarbazole (abbreviation: PCzPCN1), 4,4 ', 4 "-tris [N- (1-naphthyl) -N-phenylamino] triphenylamine Abbreviations: 1′-TNATA), 2,7-bis [N- (4-diphenylaminophenyl) -N-phenylamino] -spiro-9,9′-bifluorene (abbreviation: DPA2SF), N, N′-bis (9-phenylcarbazol-3-yl) -N, N′-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N- (9,9-dimethyl-2-diphenylamino-9H-fluorene-7- Yl) diphenylamine (abbreviation: DPNF), N, N ′, N ″ -triphenyl-N, N ′, N ″ -tris (9-phenylcarbazol-3-yl) benzene-1,3,5-triamine (Abbreviation: PCA3B), 2- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] spiro-9,9'-bifluorene (abbreviation: PCASF), 2- [N- (4-Diphenylaminophenyl) -N-phenylamino] spiro-9,9′-bifluorene (abbreviation: DPASF), N, N′-bis [4- (carbazol-9-yl) phenyl] -N, N ′ -Diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4'-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl (abbreviation: TPD), 4 , 4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), N- (9,9-dimethyl-9H-fluoren-2-yl) -N- {9 , 9-dimethyl-2- [N′-phenyl-N ′-(9,9-dimethyl-9H-fluoren-2-yl) amino] -9H-fluoren-7-yl} phenylamine (abbreviation: DF ADFL), 3- [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3- [N- (4-diphenylaminophenyl) -N- Phenylamino] -9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis [N- (4-diphenylaminophenyl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzDPA2), 4,4 ′ -Bis (N- {4- [N '-(3-methylphenyl) -N'-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD), 3,6-bis [N- (4 -Diphenylaminophenyl) -N- (1-naphthyl) amino] -9-phenylcarbazole (abbreviation: PCzTPN2), 3,6-bis [ - (9-phenyl-3-yl) -N- phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), and the like.

The electron transport layers (107a and 107b) are layers containing a substance having a high electron transport property. For the electron transport layer (107a, 107b), Alq ₃ , tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] quinolinato) beryllium (abbreviation: BeBq ₂ ) , BAlq, Zn (BOX) ₂ , bis [2- (2-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ), and the like can be used. 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis [5- (p-tert-butyl) Phenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 3- (4-tert-butylphenyl) -4-phenyl-5- (4-biphenylyl) -1 , 2,4-triazole (abbreviation: TAZ), 3- (4-tert-butylphenyl) -4- (4-ethylphenyl) -5- (4-biphenylyl) -1,2,4-triazole (abbreviation: p-EtTAZ), bathophenanthroline (abbreviation: Bphen), bathocuproin (abbreviation: BCP), 4,4′-bis (5-methylbenzoxazol-2-yl) stilbene (abbreviation: BzOs), etc. Aromatic aromatic compounds can also be used. In addition, poly (2,5-pyridinediyl) (abbreviation: PPy), poly [(9,9-dihexylfluorene-2,7-diyl) -co- (pyridine-3,5-diyl)] (abbreviation: PF -Py), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (2,2′-bipyridine-6,6′-diyl)] (abbreviation: PF-BPy) Molecular compounds can also be used. The substances mentioned here are mainly substances having an electron mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher. Note that other than the above substances, any substance that has a property of transporting more electrons than holes may be used for the electron-transport layers (107a and 107b).

Further, the electron-transporting layers (107a and 107b) are not limited to a single layer, and may be a stack of two or more layers formed using the above substances.

The electron injection layers (108a and 108b) are layers containing a substance having a high electron injection property. The electron injection layer (108a, 108b) includes an alkali metal such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), lithium oxide (LiO _x ), or an alkaline earth. Metals or their compounds can be used. Alternatively, a rare earth metal compound such as erbium fluoride (ErF ₃ ) can be used. Further, electride may be used for the electron injection layer 108. Examples of the electride include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. In addition, the substance which comprises the electron carrying layer (107a, 107b) mentioned above can also be used.

Alternatively, a composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer (108a, 108b). Such a composite material is excellent in electron injecting property and electron transporting property because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons. Specifically, for example, a substance (metal complex or heteroaromatic) that constitutes the electron transport layer (107a, 107b) described above, for example. Compounds). The electron donor may be any substance that exhibits an electron donating property to the organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and lithium, cesium, magnesium, calcium, erbium, ytterbium, and the like can be given. Alkali metal oxides and alkaline earth metal oxides are preferable, and lithium oxide, calcium oxide, barium oxide, and the like can be given. A Lewis base such as magnesium oxide can also be used. Alternatively, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can be used.

However, in the light-emitting element described in this embodiment, the optical distance between the light-emitting region in the EL layer 103b closest to the second electrode 102 and the second electrode is λ / with respect to the wavelength of light emitted in the light-emitting region. Therefore, the thickness of the EL transport layer (107b) and the electron injection layer (108b) in the EL layer 103b closest to the second electrode 102 is adjusted appropriately. It is formed so that the optical distance between the light emitting region and the second electrode is less than λ / 4.

The charge generation layer 109 may have a structure in which an electron acceptor is added to a hole transporting material or a structure in which an electron donor (donor) is added to an electron transporting material. Good. Moreover, both these structures may be laminated | stacked.

In the case where the electron acceptor is added to the hole transporting material, examples of the hole transporting material include NPB, TPD, TDATA, MTDATA, 4,4′-bis [N- (spiro-9 , 9′-bifluoren-2-yl) -N-phenylamino] biphenyl (abbreviation: BSPB), or the like can be used. The substances described here are mainly substances having a hole mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that other than the above substances, any organic compound that has a property of transporting more holes than electrons may be used.

Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ -TCNQ), chloranil, and the like. In addition, oxides of metals belonging to Groups 4 to 8 in the periodic table can be given. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron accepting properties. Among these, molybdenum oxide is especially preferable because it is stable in the air, has a low hygroscopic property, and is easy to handle.

On the other hand, when an electron donor is added to the electron transporting material, examples of the electron transporting material include a metal complex having a quinoline skeleton or a benzoquinoline skeleton, such as Alq, Almq ₃ , BeBq ₂ , BAlq, and the like. Etc. can be used. In addition, a metal complex having an oxazole-based or thiazole-based ligand such as Zn (BOX) ₂ or Zn (BTZ) ₂ can also be used. In addition to metal complexes, PBD, OXD-7, TAZ, Bphen, BCP, and the like can also be used. The substances mentioned here are mainly substances having an electron mobility of 10 ⁻⁶ cm ² / Vs or higher. Note that other than the above substances, any organic compound that has a property of transporting more electrons than holes may be used.

As the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, a metal belonging to Groups 2 and 13 of the periodic table, or an oxide or carbonate thereof can be used. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or the like is preferably used. An organic compound such as tetrathianaphthacene may be used as an electron donor.

Note that by forming the charge generation layer 109 using the above-described material, an increase in driving voltage in the case where an EL layer is stacked can be suppressed.

The hole injection layer (104a, 104b), hole transport layer (105a, 105b), light emitting layer (106a, 106b (106 (b1), 106 (b2))), electron transport layer (107a, 107b) described above. ), The electron injection layer (108a, 108b), and the charge generation layer 109 can be formed by a method such as an evaporation method (including a vacuum evaporation method), an inkjet method, or a coating method, respectively.

Note that although a light-emitting element having two EL layers is described in this embodiment mode, three or more EL layers can be stacked. Such a tandem light-emitting element can realize a light-emitting device that can be driven at a low voltage and has low power consumption.

The light-emitting element described in this embodiment has a microcavity structure and can extract light of different wavelengths (monochromatic light) even when the EL layer is the same, so that the light-emitting elements are separated (for example, RGB). Is no longer necessary. Therefore, it is advantageous in realizing full color because it is easy to realize high definition. A combination with a colored layer (color filter) is also possible. In addition, since it is possible to increase the emission intensity in the front direction of the specific wavelength, it is possible to reduce power consumption. This configuration is particularly useful when applied to a color display (image display device) using pixels of three or more colors, but may be used for purposes such as illumination.

In addition, as a structure of the light-emitting device including the light-emitting element, a passive matrix light-emitting device, an active matrix light-emitting device, or the like can be manufactured, which are all included in one embodiment of the present invention. And

Note that there is no particular limitation on the structure of the transistor (FET) in the case of manufacturing the active matrix light-emitting device. For example, a staggered or inverted staggered FET can be used as appropriate. Also, the driving circuit formed on the FET substrate may be composed of N-type and P-type FETs, or may be composed of only one of N-type FETs and P-type FETs. . Further, the crystallinity of the semiconductor film used for the FET is not particularly limited. For example, an amorphous semiconductor film or a crystalline semiconductor film can be used. Further, as a semiconductor material, an IV group (silicon, gallium, etc.) semiconductor, a compound semiconductor (including an oxide semiconductor), an organic semiconductor, or the like can be used.

Note that the structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments.

(Embodiment 2)
In this embodiment, one embodiment of a light-emitting device in the case where a light-emitting element which is one embodiment of the present invention described in Embodiment 1 is combined with a colored layer (a color filter or the like) will be described. Note that in this embodiment, a structure of a pixel portion of a light-emitting device is described with reference to FIGS.

In FIG. 2, a plurality of FETs 202 are formed on a substrate 201, and each FET 202 is electrically connected to each light emitting element (207R, 207G, 207B, 207W). Specifically, each FET 202 is electrically connected to the first electrode 203 which is a pixel electrode of the light emitting element. In addition, a partition wall 204 is provided to fill an end portion of the adjacent first electrode 203.

Note that the structure of the first electrode 203 in this embodiment mode is the same as that in Embodiment Mode 1 and functions as a reflective electrode. Further, an EL layer 205 is formed over the first electrode 203, and a second electrode 210 is formed over the EL layer 205. The structures of the EL layer 205 and the second electrode 210 are also the same as those described in Embodiment 1, and the EL layer has a plurality of light-emitting layers that exhibit a plurality of monochromatic lights. Reference numeral 210 denotes an electrode that functions as a semi-transmissive / semi-reflective electrode.

Different light emission can be obtained from each of the light emitting elements (207R, 207G, 207B, 207W). Specifically, the light-emitting element 207R is optically adjusted so as to obtain red light emission, and red light is emitted in the direction of the arrow through the colored layer 208R in the region indicated by 206R. The light-emitting element 207G is optically adjusted so that green light emission can be obtained, and green light is emitted in the direction of the arrow through the colored layer 208G in the region indicated by 206G. The light-emitting element 207B is optically adjusted so as to obtain blue light emission, and blue light is emitted in the direction of the arrow through the colored layer 208B in a region indicated by 206B. The light-emitting element 207W is optically adjusted to obtain white light emission, and white light is emitted in the direction of the arrow without passing through the colored layer in the region indicated by 206W.

Note that each colored layer (208R, 208G, 208B) is, as shown in FIG. 2, a transparent sealing substrate 211 disposed above the substrate 201 provided with each light emitting element (207R, 207G, 207B, 207W). Is provided. Each colored layer (208R, 208G, 208B) is provided at a position that overlaps with each light emitting element (207R, 207G, 207B) exhibiting the respective emission color.

Further, a black layer (black matrix) 209 is provided to fill the end portions of the adjacent colored layers (208R, 208G, 208B). Each colored layer (208R, 208G, 208B) and the black layer 209 may be covered with an overcoat layer using a transparent material.

In the configuration described above, a light emitting device having a structure in which light emission is extracted to the sealing substrate 211 side (top emission type) is obtained, but light emission having a structure in which light is extracted to the substrate 1001 side on which the FET is formed (bottom emission type). It is good also as an apparatus. Note that in the case of the top emission type light-emitting device described in this embodiment, a light-shielding substrate and a light-transmitting substrate can be used as the substrate 201, but in the case of a bottom emission type light-emitting device, It is necessary to use a light-transmitting substrate as the substrate 201.

(Embodiment 3)
In this embodiment, an active matrix light-emitting device is described with reference to FIGS. 3A and 3B as an example of a light-emitting device having a light-emitting element which is one embodiment of the present invention. Note that the light-emitting element described in Embodiment 1 can be applied to the light-emitting device described in this embodiment.

3A is a top view illustrating the light-emitting device, and FIG. 3B is a cross-sectional view taken along the chain line A-A ′ in FIG. 3A. An active matrix light-emitting device according to this embodiment includes a pixel portion 302 provided over an element substrate 301, a driver circuit portion (source line driver circuit) 303, and a driver circuit portion (gate line driver circuit) 304 ( 304a and 304b). The pixel portion 302, the driver circuit portion 303, and the driver circuit portion 304 are sealed between the element substrate 301 and the sealing substrate 306 with a sealant 305.

Further, on the element substrate 301, external input terminals that transmit external signals (eg, a video signal, a clock signal, a start signal, or a reset signal) and a potential to the driver circuit portion 303 and the driver circuit portion 304 are provided. A lead wiring 307 for connection is provided. In this example, an FPC (flexible printed circuit) 308 is provided as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

Next, a cross-sectional structure will be described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 301. Here, a driver circuit portion 303 which is a source line driver circuit and a pixel portion 302 are shown.

The drive circuit unit 303 illustrates a configuration in which the FET 309 and the FET 310 are combined. Note that the FET 309 and the FET 310 included in the driver circuit unit 303 may be formed using a circuit including a unipolar transistor (N-type or P-type only), or an N-type transistor and a P-type transistor may be included. It may be formed of a CMOS circuit including the same. In this embodiment mode, a driver integrated type in which a driver circuit is formed over a substrate is shown; however, this is not necessarily required, and the driver circuit can be formed outside the substrate.

The pixel unit 302 includes a plurality of pixels including a switching FET 311, a current control FET 312, and a first electrode (anode) 313 electrically connected to the wiring (source electrode or drain electrode) of the current control FET 312. It is formed by. In this embodiment mode, the pixel portion 302 is described as an example in which the pixel portion 302 is configured by two FETs, ie, the switching FET 311 and the current control FET 312; however, the present invention is not limited to this. For example, the pixel portion 302 may be a combination of three or more FETs and a capacitor.

As the FETs 309, 310, 311, and 312, for example, staggered or inverted staggered transistors can be applied. As a semiconductor material that can be used for the FETs 309, 310, 311, and 312, for example, a group IV (silicon, gallium, etc.) semiconductor, a compound semiconductor, an oxide semiconductor, and an organic semiconductor material can be used. Further, there is no particular limitation on the crystallinity of the semiconductor material, and for example, an amorphous semiconductor film or a crystalline semiconductor film can be used. In particular, an oxide semiconductor is preferably used as the FETs 309, 310, 311, and 312. Examples of the oxide semiconductor include In—Ga oxide and In—M—Zn oxide (M is Al, Ga, Y, Zr, La, Ce, or Nd). By using an oxide semiconductor material with an energy gap of 2 eV or more, preferably 2.5 eV or more, more preferably 3 eV or more as the FETs 309, 310, 311 and 312, the off-state current of the transistor can be reduced.

A partition wall 314 made of an insulating material is formed so as to cover the end portion of the first electrode 313. Here, the partition 314 is formed using a positive photosensitive acrylic resin. In this embodiment, the first electrode 313 is used as an anode.

In addition, it is preferable that a curved surface having a curvature is formed at the upper end portion or the lower end portion of the partition wall 314. By forming the shape of the insulator 314 as described above, the coverage of a film formed over the partition 314 can be improved. For example, a negative photosensitive resin or a positive photosensitive resin can be used as a material for the partition wall 314, and not only an organic compound but also an inorganic compound such as silicon oxide, silicon oxynitride, or nitride Silicon or the like can be used.

An EL layer 315 and a second electrode 316 are stacked over the first electrode 313. The EL layer 315 is provided with at least a light-emitting layer, and the light-emitting element 317 including the first electrode 313, the EL layer 315, and the second electrode 316 has the structure described in Embodiment 1. Embodiment 1 may be referred to for the structure of the EL layer 315.

Note that as the material used for the first electrode 313, the EL layer 315, and the second electrode 316, the material described in Embodiment 1 can be used. Although not shown here, the second electrode (cathode) 316 is electrically connected to the FPC 308 which is an external input terminal.

3B illustrates only one light-emitting element 317, the pixel portion 302 includes a plurality of light-emitting elements arranged in a matrix as described in Embodiment Mode 2. It shall be. That is, in the pixel portion 302, light emitting elements capable of emitting four types of light (R, G, B, and W) can be formed, and a light emitting device capable of full color display can be formed. In addition to light emitting elements that can emit four types of light (R, G, B, W), a light emitting element that emits light such as yellow (Y), magenta (M), and cyan (C) is formed. May be.

Further, the sealing substrate 306 is bonded to the element substrate 301 with the sealant 305, whereby the light-emitting element 317 is provided in the space 318 surrounded by the element substrate 301, the sealing substrate 306, and the sealant 305. ing. Note that the space 318 includes a structure filled with the sealant 305 in addition to a case where the space 318 is filled with an inert gas (nitrogen, argon, or the like).

Note that an epoxy resin or glass frit is preferably used for the sealant 305. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiber-Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used as a material for the sealing substrate 306. When glass frit is used as the sealing material, the element substrate 301 and the sealing substrate 306 are preferably glass substrates from the viewpoint of adhesiveness.

As described above, an active matrix light-emitting device can be obtained. Note that as the light-emitting device, a passive matrix light-emitting device to which the light-emitting element having the element structure described in Embodiment 1 is applied can be manufactured.

Note that the structure described in this embodiment can be combined with any of the structures described in other embodiments as appropriate.

(Embodiment 4)
In this embodiment, examples of various electronic devices completed using a light-emitting device manufactured using the light-emitting element which is one embodiment of the present invention will be described with reference to FIGS.

As electronic devices to which the light-emitting device is applied, for example, a television set (also referred to as a television or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (a mobile phone, a mobile phone) Also referred to as a telephone device), portable game machines, portable information terminals, sound reproduction devices, large game machines such as pachinko machines, and the like. Specific examples of these electronic devices are shown in FIGS.

FIG. 4A illustrates an example of a television device. In the television device 7100, a display portion 7103 is incorporated in a housing 7101. Images can be displayed on the display portion 7103, and a light-emitting device can be used for the display portion 7103. Here, a structure in which the housing 7101 is supported by a stand 7105 is shown.

The television device 7100 can be operated with an operation switch included in the housing 7101 or a separate remote controller 7110. Channels and volume can be operated with an operation key 7109 provided in the remote controller 7110, and an image displayed on the display portion 7103 can be operated. The remote controller 7110 may be provided with a display portion 7107 for displaying information output from the remote controller 7110.

Note that the television device 7100 is provided with a receiver, a modem, and the like. General TV broadcasts can be received by a receiver, and connected to a wired or wireless communication network via a modem, so that it can be unidirectional (sender to receiver) or bidirectional (sender and receiver). It is also possible to perform information communication between each other or between recipients).

FIG. 4B illustrates a computer, which includes a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. Note that the computer can be manufactured by using the light-emitting device for the display portion 7203.

FIG. 4C illustrates a smart watch, which includes a housing 7302, a display panel 7304, operation buttons 7311 and 7312, a connection terminal 7313, a band 7321, a clasp 7322, and the like.

A display panel 7304 mounted on a housing 7302 also serving as a bezel portion has a non-rectangular display region. The display panel 7304 can display an icon 7305 indicating time, another icon 7306, and the like.

Note that the smart watch illustrated in FIG. 4C can have a variety of functions. For example, a function for displaying various information (still images, moving images, text images, etc.) on the display unit, a touch panel function, a function for displaying a calendar, date or time, a function for controlling processing by various software (programs), Wireless communication function, function for connecting to various computer networks using the wireless communication function, function for transmitting or receiving various data using the wireless communication function, and reading and displaying programs or data recorded on the recording medium It can have a function of displaying on the section.

In addition, a speaker, a sensor (force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current are included in the housing 7302. , Voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared measurement function), microphone, and the like. Note that a smart watch can be manufactured by using a light-emitting device for the display panel 7304.

FIG. 4D illustrates an example of a mobile phone (including a smartphone). A cellular phone 7400 is provided with a display portion 7402, a microphone 7406, a speaker 7405, a camera 7407, an external connection portion 7404, an operation button 7403, and the like in a housing 7401. In the case where a light-emitting element is manufactured by forming the light-emitting element according to one embodiment of the present invention over a flexible substrate, the light-emitting element can be applied to the display portion 7402 having a curved surface as illustrated in FIG. Is possible.

Information can be input to the cellular phone 7400 illustrated in FIG. 4D by touching the display portion 7402 with a finger or the like. In addition, operations such as making a call or creating a mail can be performed by touching the display portion 7402 with a finger or the like.

There are mainly three screen modes of the display portion 7402. The first mode is a display mode mainly for displaying an image. The first is a display mode mainly for displaying images, and the second is an input mode mainly for inputting information such as characters. The third is a display + input mode in which the display mode and the input mode are mixed.

For example, when making a call or creating a mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and an operation for inputting characters displayed on the screen may be performed. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402.

In addition, by providing a detection device such as a gyro sensor or an acceleration sensor inside the mobile phone 7400, the orientation (portrait or horizontal) of the mobile phone 7400 is determined, and the screen display of the display portion 7402 is automatically switched. Can be.

The screen mode is switched by touching the display portion 7402 or operating a button 7403 of the housing 7401. Further, switching can be performed depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display unit is moving image data, the mode is switched to the display mode, and if it is text data, the mode is switched to the input mode.

Further, in the input mode, when a signal detected by the optical sensor of the display unit 7402 is detected and there is no input by a touch operation of the display unit 7402 for a certain period, the screen mode is switched from the input mode to the display mode. You may control.

The display portion 7402 can function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger and capturing an image of a palm print, a fingerprint, or the like. In addition, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display portion, finger veins, palm veins, and the like can be imaged.

Furthermore, as another configuration of the cellular phone (including a smartphone), the present invention can be applied to a cellular phone having a structure as illustrated in FIG. 4 (D′-1) or FIG. 4 (D′-2).

Note that in the case of the structure shown in FIG. 4D′-1 or FIG. 4D′-2, character information, image information, or the like is sent to the first of the housings 7500 (1) and 7500 (2). In addition to the surfaces 7501 (1) and 7501 (2), the images can be displayed on the second surfaces 7502 (1) and 7502 (2). By having such a structure, the user can easily use the character information and image information displayed on the second surface 7502 (1), 7502 (2), etc. while the mobile phone is stored in the breast pocket. Can be confirmed.

As described above, an electronic device can be obtained by using the light-emitting device including the light-emitting element which is one embodiment of the present invention. Note that applicable electronic devices are not limited to those shown in this embodiment, and can be applied to electronic devices in various fields.

Note that the structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments.

(Embodiment 5)
In this embodiment, an example of a lighting device to which a light-emitting device including a light-emitting element which is one embodiment of the present invention is applied will be described with reference to FIGS.

FIG. 5 illustrates an example in which the light-emitting device is used as an indoor lighting device 8001. Note that since the light-emitting device can have a large area, a large-area lighting device can also be formed. In addition, by using a housing having a curved surface, the lighting device 8002 in which the light emitting region has a curved surface can be formed. A light-emitting element included in the light-emitting device described in this embodiment has a thin film shape, and the degree of freedom in designing a housing is high. Therefore, it is possible to form a lighting device with various designs. Further, a large lighting device 8003 may be provided on the wall surface of the room.

Further, by using the light-emitting device on the surface of the table, the lighting device 8004 having a function as a table can be obtained. Note that a lighting device having a function as furniture can be obtained by using a light-emitting device for part of other furniture.

As described above, various lighting devices to which the light-emitting device is applied can be obtained. Note that these lighting devices are included in one embodiment of the present invention.

The structure described in this embodiment can be combined as appropriate with any of the structures described in the other embodiments.

In this example, light-emitting elements 1 to 4 which are one embodiment of the present invention were manufactured. Details of the element structure will be described with reference to FIG. In addition, chemical formulas of materials used in this example are shown below.

<< Production of Light-Emitting Element 1, Light-Emitting Element 2, Light-Emitting Element 3, and Light-Emitting Element 4 >>
FIG. 6 shows a laminated structure of the light emitting elements 1 to 4 described in this embodiment. The light emitting element 1 emits red light, the light emitting element 2 emits green light, and the light emitting element 3 emits green light. In addition, since the light emitting element 4 is configured to emit white light, the optical adjustment is performed so that the respective emission colors can be obtained. Specifically, optical adjustment is performed by changing the thicknesses of the first electrode 4001 and the first hole injection layer 4011a for each light emitting element. Each of these light-emitting elements has a structure in which light is emitted from the second electrode 4003 side. Although not shown in FIG. 6, a color filter for extracting red light emission is provided on the second electrode 4003 side (above the second electrode 4003 in FIG. 6) that overlaps with the light-emitting element 1. In addition, a color filter for extracting green light emission is provided on the second electrode 4003 side overlapping with the light emitting element 2, and blue light emission is extracted on the second electrode 4003 side overlapping with the light emitting element 3. Therefore, light emission with high color purity corresponding to each emission color can be obtained. Further, it is not necessary to provide such a color filter on the second electrode 4003 side which overlaps with the light-emitting element 4, and white light emission can be obtained from the second electrode 4003 side.

The first electrode 4101 is an electrode that functions as an anode, and an alloy film (Al—Ni—La) of aluminum (Al), titanium (Ti), and lanthanum (La) is formed on a glass substrate 4000 by a sputtering method. After forming a film with a thickness of 200 nm, Ti was formed with a thickness of 6 nm by a sputtering method, and indium tin oxide containing silicon oxide (ITSO) was further formed by a sputtering method. Note that part or all of the deposited Ti is oxidized and contains titanium oxide. The electrode area was 2 mm × 2 mm.

Here, as a pretreatment, the surface of the substrate 4000 was washed with water, baked at 200 ° C. for 1 hour, and then subjected to UV ozone treatment for 370 seconds. Thereafter, the substrate is introduced into a vacuum vapor deposition apparatus whose internal pressure is reduced to about 10 ⁻⁴ Pa, vacuum baking is performed at 170 ° C. for 60 minutes in a heating chamber within the vacuum vapor deposition apparatus, and then the substrate 4000 is formed for about 30 minutes. Allowed to cool.

A first EL layer 4002a, a charge generation layer 4004, a second EL layer 4002b, and a second electrode 4003 are sequentially formed over the first electrode 4001. Note that the first EL layer 4002a includes a first hole-injection layer 4011a, a first hole-transport layer 4012a, a light-emitting layer (A) (4013a), a first electron-transport layer 4014a, and first electrons. An injection layer 4015a is included, and the second EL layer 4002b includes a second hole injection layer 4011b, a second hole transport layer 4012b, a light emitting layer (B) 4013b, a second electron transport layer 4014b, 2 electron injection layers 4015b are included.

The first hole injection layer 4011a is formed by reducing the pressure in the vacuum apparatus to 10 ⁻⁴ Pa and then 9- {4- (9-H-9-phenylcarbazol-3-yl) -phenyl} -phenanthrene (abbreviation: PcPPn) and molybdenum oxide (VI) were formed on the first electrode 4001 by co-evaporation so that PcPPn: molybdenum oxide = 1: 0.5 (mass ratio). Co-evaporation is an evaporation method in which a plurality of different substances are simultaneously evaporated from different evaporation sources. Note that in the case of the light-emitting element 1, the film thickness was 90 nm, in the case of the light-emitting element 2, the film thickness was 40 nm, in the case of the light-emitting element 3, the film thickness was 5 nm, and in the case of the light-emitting element 4, the film thickness was 20 nm.

The first hole transport layer 4012a was formed by depositing PcPPn with a thickness of 15 nm on the first hole injection layer 4011a.

The light-emitting layer (A) 4013a is formed using 9- [4- (10-phenyl-9-anthracenyl) phenyl] -9H-carbazole (abbreviation: CzPA), N, N′-bis on the first hole-transport layer 4012a. (3-Methylphenyl) -N, N′-bis [3- (9-phenyl-9H-fluoren-9-yl) phenyl] -pyrene-1,6-diamine (abbreviation: 1,6 mM emFLPAPrn) was replaced with CzPA: It was formed by co-evaporation so that 1,6 mM emFLPAPrn = 1: 0.05 (mass ratio). The film thickness was 30 nm.

The first electron-transport layer 4014a was formed by depositing CzPA with a thickness of 5 nm on the light-emitting layer (A) 4013a and then depositing 15 nm of bathophenanthroline (abbreviation: Bphen).

The first electron injection layer 4015a was formed by depositing lithium oxide (Li ₂ O) with a thickness of 0.1 nm on the first electron transport layer 4014a.

The charge generation layer 4004 was formed by depositing copper phthalocyanine (abbreviation: CuPc) with a thickness of 2 nm on the first electron-injection layer 4015a.

The second hole injection layer 4011b includes 1,3,5-tri (dibenzothiophen-4-yl) -benzene (abbreviation: DBT3P-II) and molybdenum oxide (VI) over the charge generation layer 4004. DBT3P-II: Molybdenum oxide = 1: 0.5 (mass ratio) was formed by co-evaporation. The film thickness was 20 nm.

The second hole transport layer 4012b was formed by depositing BPAFLP with a thickness of 20 nm on the second hole injection layer 4011b.

The light-emitting layer (B) 4013b has a stacked structure including two layers of a first light-emitting layer 4013 (b1) and a second light-emitting layer 4013 (b2).

The first light-emitting layer 4013 (b1) is formed over the second hole-transport layer 4012b with 2- [3 ′-(dibenzothiophen-4-yl) biphenyl-3-yl] dibenzo [f, h] quinoxaline ( Abbreviation: 2mDBTBPDBq-II), 4,4′-di (1-naphthyl) -4 ″-(9-phenyl-9H-carbazol-3-yl) triphenylamine (abbreviation: PCBNBB), (acetylacetonato) Bis (6-tert-butyl-4-phenylpyrimidinato) iridium (III) (abbreviation: [Ir (tBupppm) ₂ (acac)]) is replaced with 2mDBTBBPDBq-II: PCNBBB: [Ir (tBupppm) ₂ (acac) ] = 0.7: 0.3: 0.06 (mass ratio). The film thickness was 20 nm.

The second light-emitting layer 4013 (b2) is formed over the first light-emitting layer 4013 (b1) with 2mDBTBBPDBq-II, PCBNBB, bis {4,6-dimethyl-2- [5- (2,6-dimethylphenyl)- 3- (3,5-dimethylphenyl) -2-pyrazinyl-κN] phenyl-κC} (2,4-pentanedionato-κ ² O, O ′) iridium (III) (abbreviation: [Ir (dmdppr-dmp ) ₂ (acac)]) was co-evaporated to be 2mDBTBPDBq-II: [Ir (dmdppr-dmp) ₂ (acac)] = 1: 0.06 (mass ratio). The film thickness was 20 nm.

The second electron-transport layer 4014b was formed by vapor-depositing 15 nm of 2mDBTPDBq-II on the second light-emitting layer 4013 (b2) and then depositing 15 nm of Bphen.

The second electron injection layer 4015b was formed by depositing 1 nm of lithium fluoride (LiF) on the second electron transport layer 4014b.

The second electrode 4003 is an electrode functioning as a cathode, and silver (Ag) and magnesium (Mg) are co-evaporated 1: 0.1 on the second electron injection layer 4015b to a thickness of 10 nm. After the formation, indium tin oxide (ITO) was formed to a thickness of 50 nm by a sputtering method. Note that, in the above-described vapor deposition process, the vapor deposition was all performed by a resistance heating method.

Although not shown in FIG. 6, the color filters (colored layers) provided in the light-emitting element 1, the light-emitting element 2, and the light-emitting element 3 are all formed on the counter substrate and formed on the substrate 4000. After arranging each light emitting element and the position of the color filter so as to overlap each other, sealing was performed by attaching them to these counter substrates in a glove box in a nitrogen atmosphere so as not to be exposed to the atmosphere (a sealing material was placed around the element). This was applied, and irradiated with 6 J / cm ² of 365 nm ultraviolet light at the time of sealing, and heat-treated at 80 ° C. for 1 hour).

Table 1 shows element structures of the light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4 obtained as described above.

<< Operation Characteristics of Light-Emitting Element 1, Light-Emitting Element 2, Light-Emitting Element 3, and Light-Emitting Element 4 >>
The operating characteristics of each manufactured light emitting element were measured. The measurement was performed at room temperature (atmosphere kept at 25 ° C.). The results are shown in FIGS.

In addition, Table 2 below shows main initial characteristic values of the light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4 around 1000 cd / m ² .

From the above results, the light-emitting element 1 manufactured in this example has high current efficiency, and can obtain red light emission with high color purity near the red chromaticity defined by NTSC (National Television Standards Committee). The light-emitting element 2 has good current efficiency and exhibits green light emission with good color purity near the green chromaticity determined by NTSC, and the light-emitting element 3 has good current efficiency and near the blue chromaticity determined by NTSC As a result, the light-emitting element 4 exhibits white light emission that has a good current efficiency and a correlated color temperature that falls within the white specified range of indoor lighting as defined in JIS standards. It was.

Further, FIG. 9 shows emission spectra obtained when a current was passed through the light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4 at a current density of ^2.5 mA / cm ² . As shown in FIG. 9, the emission spectrum of the light-emitting element 1 has a peak around 614 nm, the emission spectrum of the light-emitting element 2 has a peak around 540 nm, and the emission spectrum of the light-emitting element 3 has a peak around 463 nm. The spectrum shape is shown. On the other hand, the emission spectrum of the light emitting element 4 shows a broad spectrum shape having a peak from around 550 nm to around 610 nm.

The light-emitting element 1, the light-emitting element 2, the light-emitting element 3, and the light-emitting element 4 described in this example are light-emitting elements formed over the same substrate, and the first electrode in the light-emitting layer (B) is formed from the second electrode. The structure is optically adjusted so that the optical distance to the interface between the light emitting layer 4013 (b1) and the second light emitting layer 4013 (b2) is less than λ / 4. The above results show that, by adopting such an element structure, a light emitting element 1 that emits red light, a light emitting element 2 that emits green light, and a light emitting element that emits blue light having good color purity determined by NTSC on the same substrate. 3 can be formed, and it is shown that the light emitting element 4 which can obtain white light emission (without using a color filter) within the JIS standard range is formed.

In this example, an active matrix flexible display manufactured using a light-emitting element which is one embodiment of the present invention will be described. This active matrix flexible display is an RGBW type composed of the light emitting elements 1 to 4 having the element structure shown in the first embodiment.

The structure of the flexible display is a so-called side roll structure, and in the production thereof, a peeling transfer method using an inorganic peeling layer was used, and an FET using an oxide semiconductor was used for the driver circuit portion.

Table 3 below shows the main specifications of the manufactured RGBW type flexible display and the characteristics at 100 cd / m ² , white light emission.

Note that in terms of power consumption, an RGB type flexible display manufactured with the same specifications was 1896 mW. Therefore, it was found that the RGBW type flexible display shown in this example is a display that can reduce power consumption by about 20% compared to the RGB type due to the contribution of the W element.

FIG. 10 shows a photograph of the appearance of the produced RGBW type flexible display.

101 First electrode 102 Second electrode 103a, 103b EL layer 104a, 104b Hole injection layer 105a, 105b Hole transport layer 106a Light emitting layer 106b Light emitting layer 106 (b1), 106 (b2) Light emitting layer 107a, 107b Electron Transport layers 108a and 108b Electron injection layer 109 Charge generation layer 201 Substrate 202 FET
203 First electrode 204 Partition 205 EL layers 206R, 206G, 206B, 206W Light emitting regions 207R, 207G, 207B, 207W Light emitting elements 208R, 208G, 208B Colored layer 209 Black layer (black matrix)
210 Second electrode 211 Sealing substrate 301 Element substrate 302 Pixel portion 303 Drive circuit portion (source line drive circuit)
304a, 404b Drive circuit section (gate line drive circuit)
305 Sealing material 306 Sealing substrate 307 Wiring 308 FPC (flexible printed circuit)
309 FET
310 FET
311 Switching FET
312 Current control FET
313 First electrode 314 Partition 315 EL layer 316 Second electrode 317 Light emitting element 318 Space 4000 Substrate 4001 First electrode 4002a, 4002b EL layer 4003 Second electrode 4004 Charge generation layer 4011a, 4011b Hole injection layer 4012a, 4012b Hole transport layer 4013a, 4013b Light emitting layer 4013 (b1), 4013 (b2) Light emitting layer 4014a, 4014b Electron transport layer 4015a, 4015b Electron injection layer 7100 Television apparatus 7101 Housing 7103 Display unit 7105 Stand 7107 Display unit 7109 Operation Key 7110 Remote controller 7201 Main body 7202 Case 7203 Display unit 7204 Keyboard 7205 External connection port 7206 Pointing device 7302 Case 7304 Display panel 7305 CON 7306 Other icons 7311 Operation button 7312 Operation button 7313 Connection terminal 7321 Band 7322 Clasp 7400 Mobile phone 7401 Case 7402 Display unit 7403 Operation button 7404 External connection unit 7405 Speaker 7406 Microphone 7407 Camera 8001 Illumination device 8002 Illumination device 8003 Illumination Device 8004 lighting device

Claims (9)

Having a plurality of EL layers between a pair of electrodes consisting of a reflective electrode and a semi-transmissive / semi-reflective electrode;
The plurality of EL layers are stacked via a charge generation layer,
The light emitting device, wherein an optical distance from the light emitting region of the EL layer closest to the semi-transmissive / semi-reflective electrode to the semi-transmissive / semi-reflective electrode among the plurality of EL layers is less than λ / 4. It has two EL layers between a pair of electrodes consisting of a reflective electrode and a semi-transmissive / semi-reflective electrode,
The two EL layers are stacked via a charge generation layer,
Of the two EL layers, the EL layer on the semi-transmissive / semi-reflective electrode side has two light emitting layers stacked,
An optical distance from the semi-transmissive / semi-reflective electrode to the interface between the two light-emitting layers is less than λ / 4. It has two EL layers between a pair of electrodes consisting of a reflective electrode and a semi-transmissive / semi-reflective electrode,
The two EL layers are stacked via a charge generation layer,
Of the two EL layers, the EL layer on the semi-transmissive / semi-reflective electrode side has two light emitting layers stacked,
Each of the two light emitting layers exhibits phosphorescence having different emission colors,
An optical distance from the semi-transmissive / semi-reflective electrode to the interface between the two light-emitting layers is less than λ / 4. It has two EL layers between a pair of electrodes consisting of a reflective electrode and a semi-transmissive / semi-reflective electrode,
The two EL layers are stacked via a charge generation layer,
Of the two EL layers, one EL layer on the reflective electrode side has a light emitting layer exhibiting fluorescence, and the other EL layer has two light emitting layers stacked,
Each of the two light emitting layers exhibits phosphorescence having different emission colors,
An optical distance from the semi-transmissive / semi-reflective electrode to the interface between the two light-emitting layers is less than λ / 4. It has two EL layers between a pair of electrodes consisting of a reflective electrode and a semi-transmissive / semi-reflective electrode,
The two EL layers are stacked via a charge generation layer,
Of the two EL layers, one EL layer on the reflective electrode side includes a light emitting layer that emits blue light, and the other EL layer includes a light emitting layer that emits green light in order from the reflective electrode side, and red It has a structure in which a light emitting layer that emits light is laminated,
An optical distance from the semi-transmissive / semi-reflective electrode to an interface between the light-emitting layer exhibiting green light emission and the light-emitting layer exhibiting red light emission is less than λ / 4. It has two EL layers between a pair of electrodes consisting of a reflective electrode and a semi-transmissive / semi-reflective electrode,
The two EL layers are stacked via a charge generation layer,
Of the two EL layers, one EL layer on the reflective electrode side has a light emitting layer that emits blue fluorescent light, and the other EL layer is a light emitting layer that emits green phosphorescent light in order from the reflective electrode side. And having a structure in which a light emitting layer exhibiting red phosphorescence is laminated,
An optical distance from the semi-transmissive / semi-reflective electrode to an interface between the light-emitting layer exhibiting green phosphorescence emission and the light-emitting layer exhibiting red phosphorescence emission is less than λ / 4.   A light-emitting device using the light-emitting element according to claim 1.   An electronic apparatus using the light emitting device according to claim 7.   An illumination device using the light emitting device according to claim 7.