JP4438364B2 - Organic light emitting device and display device - Google Patents

Description

  The present invention relates to an organic light emitting device and a display device having a white light emitting layer, and in particular, an organic light emitting device in which the white light emitting layer is composed of two types of light emitting layers of orange and blue, and a display having the organic light emitting device. Relates to the device.

  Organic light-emitting devices are expected to be applied to thin displays as light-emitting devices that are self-luminous and have no viewing angle dependency and can realize a complete solid structure. Among organic light-emitting elements, white organic light-emitting elements realize a full-color display without separately painting each pixel by modulating white light emission to the three primary colors of blue, green, and red that constitute the display using a color filter or the like. It is possible. Therefore, it is possible to avoid a decrease in the yield due to the separate coating cost and the separate coating, and it is a particularly effective method in realizing a large screen display. In addition, it is expected to be used as a backlight or a surface light source using white light emission.

  This white organic light emitting element generally has a structure in which a transparent electrode provided on a transparent substrate such as glass is used as an anode, and an organic layer and a cathode are stacked thereon. In general, the organic layer is composed of a plurality of layers including a light emitting layer, and includes, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, or any combination thereof. By using an appropriate guest material (light-emitting material, dopant material) in combination with the host material for the light-emitting layer, light emission efficiency, lifetime, and emission spectrum can be adjusted. In this organic light emitting device, when a DC voltage is applied between the anode and the cathode, holes and electrons injected from the anode and the cathode recombine in the light emitting layer, and the emitted light is extracted from the transparent electrode side. .

  In addition to this structure, it is also possible to adopt a top emission structure (top emission) in which the electrode opposite to the substrate is formed of a transparent electrode and light is extracted from the transparent electrode side on the top surface. With such a top emission structure, the active matrix type element using TFT (Thin Film Transistor) can increase the light extraction aperture ratio.

In a white organic light emitting device, there are a method of laminating light emitting layers of each color in order to realize white light emission, and a method of doping (adding) a plurality of pigments into one light emitting layer. A method using three wavelength components of green, red (for example, Patent Document 1) and a method using two wavelength components having a complementary color relationship of blue and orange or blue-green and red (for example, Patent Document 2) have been proposed. ing.
Japanese Patent Laid-Open No. 10-3990 JP 2002-329578 A

  However, in the former method (Patent Document 1), a chromaticity change occurs with a change in EL (Electroluminescence) spectrum depending on a current value, and a light emitting region is formed by forming a light emitting layer in a three-layer structure. There is a problem that the luminous efficiency is lowered due to dispersion. In addition, the latter method (Patent Document 1) has a simpler device structure and less chromaticity change and lower emission efficiency than the former method, but has sufficiently high efficiency and high reliability. Did not have.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an organic light-emitting element and a display device with improved white light emission efficiency and reduced chromaticity change and improved reliability. is there.

An organic light emitting device according to the present invention includes an organic layer including at least an orange light emitting layer and a blue light emitting layer between a first electrode and a second electrode, and the orange light emitting layer is 9,10-di- (2-naphthyl). ) An anthracene (ADN) or a host material composed of a mixture of 9,10-di- (2-naphthyl) anthracene and a hole transport material, and a guest material composed of a styryl compound represented by Chemical formula 1 der Ru.

（化１において、Ｘは化２ないし化８に示した基のうちのいずれかを表し、Ｙは化９ないし化１１に示した基のうちのいずれかを表す。）

（化２において、Ｒ¹ ないしＲ⁵ は少なくとも一つがハロゲン原子、ニトロ基、シアノ基、トリフルオロメチル基、置換基を有してもよいアルキル基、および置換基を有してもよいアルコキシル基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

（化３ないし化８において、Ｒ⁶ ないしＲ⁵⁵は、水素原子、ハロゲン原子、ニトロ基、シアノ基、トリフルオロメチル基、置換基を有してもよいアルキル基、および置換基を有してもよいアルコキシル基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

（化９において、Ｚ¹ およびＺ² は、水素原子、置換基を有してもよいアルキル基、および置換基を有してもよいアリール基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

（化１０および１１において、Ｒ⁵⁶ないしＲ⁷²は、水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよいアルコキシル基、ハロゲン原子、ニトロ基、シアノ基およびトリフルオロメチル基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

(In Chemical Formula 1, X represents any of the groups shown in Chemical Formulas 2 to 8, and Y represents any of the groups shown in Chemical Formulas 9 to 11.)

(In Chemical Formula 2, at least one of R ¹ to R ⁵ is a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and an alkoxyl group which may have a substituent. Represents a group selected from the above, and they may be the same or different.)

(In the chemical formulas 3 to 8, R ⁶ to R ⁵⁵ have a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and a substituent. Represents a group selected from good alkoxyl groups, which may be the same or different.)

(In Formula 9, Z ¹ and Z ² represent a group selected from a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent, and they are the same. Or different.)

(In the chemical formulas 10 and 11, R ⁵⁶ to R ⁷² are a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxyl group which may have a substituent, Represents a group selected from a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, which may be the same or different.)

The organic light emitting device of the present invention, the guest material in the orange light emitting layer, the content to the host material is preferably less 10 mol%.

Viewing device that by the present invention, Ru der those with organic light-emitting device of the present invention.

Organic light-emitting element frame other invention according to Table示装location of the present invention, the host material together with a guest material of the orange light emitting layer, using a styryl compound as a high luminous efficiency and good reliability red light-emitting material 9,10-di- (2-naphthyl) anthracene (ADN), or a mixture of 9,10-di- (2-naphthyl) anthracene and a hole transport material. Thus, by combining with a blue light emitting layer having a complementary color relationship and good chromaticity, the light emission efficiency of white light is improved and the change in chromaticity is reduced, thereby improving the reliability. In particular, when the content of the styryl compound with respect to the host material is 10 mol% or less, preferable orange light emission of 590 nm or less can be obtained, and a white organic light-emitting element with better chromaticity can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 shows a cross-sectional structure of a so-called bottom emission type organic light emitting device according to a first embodiment of the present invention. This organic light-emitting element is used for an ultra-thin organic light-emitting display device. For example, a first electrode (anode) 12, an organic layer 13, and a first electrode are formed on a substrate 11 made of an insulating material such as glass. Two electrodes (cathodes) 14 are stacked in this order. A protective film (not shown) is formed on the second electrode 14.

  The first electrode 12 is a conductive material having a large work function that is transparent in the visible light region so as to extract light from the substrate 11 side, such as tin oxide (SnO 2), indium tin oxide (ITO), zinc oxide. It is made of (ZnO), titanium oxide (TiO2) or the like. The thickness of the first electrode 12 in the stacking direction (hereinafter simply referred to as thickness) is, for example, about 100 nm.

  The organic layer 13 includes, for example, a hole injection layer 13A, a hole transport layer 13B, an orange light emitting layer 13C, a blue light emitting layer 13D, an electron transport layer 13E, and an electron injection layer 13F from the first electrode 12 side. It has the structure laminated | stacked in this order. The hole injection layer 13A and the hole transport layer 13B are for increasing the efficiency of hole injection into the orange light emitting layer 13C and the blue light emitting layer 13D. The orange light-emitting layer 13C and the blue light-emitting layer 13D generate orange light and blue light by recombination of electrons and holes due to voltage application to the first electrode 12 and the second electrode 14, respectively. . In the present embodiment, a mixed color (white) of the light emission color from the orange light emission layer 13C and the light emission color from the blue light emission layer 13D is extracted downward from the first electrode 12 side. The electron transport layer 13E and the electron injection layer 13F are for increasing the efficiency of electron injection into the orange light emitting layer 13C and the blue light emitting layer 13D.

  The hole injection layer 13A and the hole transport layer 13B are layers designed so that holes are efficiently injected and transported from the anode electrode. The hole injection layer 13A and the hole transport layer 13B may be made of the same material, but may be made of different materials in order to improve hole injection and transport performance. Further, each of the hole injection layer 13A and the hole transport layer 13B may be composed of a plurality of mixtures, or may have a structure in which a plurality of types of materials are stacked.

  Examples of the material (hole transport material) for forming the hole injection layer 13A and the hole transport layer 13B include benzidine or a derivative thereof, styrylamine or a derivative thereof, triphenylmethane or a derivative thereof, porphyrin or a derivative thereof, triazole Or derivatives thereof, imidazole or derivatives thereof, oxadiazole or derivatives thereof, polyarylalkanes or derivatives thereof, phenylenediamine or derivatives thereof, arylamines or derivatives thereof, oxazoles or derivatives thereof, anthracene or derivatives thereof, fluorenone or derivatives thereof, Hydrazone or derivatives thereof, stilbene or derivatives thereof, phthalocyanine or derivatives thereof, polycyan compounds, vinyl carbazole compounds, thiophene compounds, aniline compounds Monomers heterocyclic conjugated system compounds such as, oligomers, polymers, and the like.

  Specific examples of such a hole transport material include α-naphthylphenyldiamine (α-NPD) represented by Chemical Formula 12, porphyrin, metal tetraphenylporphyrin, metal naphthalocyanine, 4,4 ′, 4 ″. -Trimethyltriphenylamine, 4,4 ', 4 "-tris (3-methylphenylphenylamino) triphenylamine (m-MTDATA), N, N, N', N'-tetrakis (p-tolyl) p- Phenylenediamine, N, N, N ′, N′-tetraphenyl-4,4′-diaminobiphenyl, N-phenylcarbazole, 4-di-p-tolylaminostilbene, poly (paraphenylenevinylene), poly (thiophenevinylene) ), Poly (2,2′-thienylpyrrole) and the like.

  The orange light emitting layer 13C is obtained by doping (adding) a styryl compound represented by Chemical formula 14 as a guest material into a host material. As the host material, for example, at least one selected from blue host materials such as 9,10-di- (2-naphthyl) anthracene (ADN) represented by Chemical Formula 13, green host materials, and red host materials A host material, a hole transport material, or a mixture of at least one host material selected from a blue host material, a red host material, and a green host material and a hole transport material.

（化１４において、Ｘは化１５ないし化２１に示した基のうちのいずれかを表し、Ｙは化２２ないし化２４に示した基のうちのいずれかを表す。）

（化１５において、Ｒ¹ ないしＲ⁵ は少なくとも一つがハロゲン原子、ニトロ基、シアノ基、トリフルオロメチル基、置換基を有してもよいアルキル基、および置換基を有してもよいアルコキシル基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

（化１６ないし化２１において、Ｒ⁶ ないしＲ⁵⁵は、水素原子、ハロゲン原子、ニトロ基、シアノ基、トリフルオロメチル基、置換基を有してもよいアルキル基、および置換基を有してもよいアルコキシル基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

（化２２において、Ｚ¹ およびＺ² は、水素原子、置換基を有してもよいアルキル基、および置換基を有してもよいアリール基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

（化２３および２４において、Ｒ⁵⁶ないしＲ⁷²は、水素原子、置換基を有してもよいアルキル基、置換基を有してもよいアリール基、置換基を有してもよいアルコキシル基、ハロゲン原子、ニトロ基、シアノ基およびトリフルオロメチル基から選ばれた基を表し、それらは同一であっても異なっていてもよい。）

(In the chemical formula 14, X represents any of the groups shown in chemical formulas 15 to 21, and Y represents any of the groups shown in chemical formulas 22 to 24.)

(In the chemical formula 15, at least one of R ¹ to R ⁵ is a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and an alkoxyl group which may have a substituent. Represents a group selected from the above, and they may be the same or different.)

(In the chemical formulas 16 to 21, R ⁶ to R ⁵⁵ have a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and a substituent. Represents a group selected from good alkoxyl groups, which may be the same or different.)

(In the chemical formula 22, Z ¹ and Z ² represent a group selected from a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent, and they are the same. Or different.)

(In the chemical formulas 23 and 24, R ⁵⁶ to R ⁷² are a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, an alkoxyl group which may have a substituent, Represents a group selected from a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, which may be the same or different.)

  Here, the content of the styryl compound (guest material) constituting the orange light emitting layer 13C with respect to the host material is desirably 10 mol% or less. This is due to the following reason.

  In the orange light emitting layer 13C, when the doping concentration of the styryl compound is increased, the spectrum shifts to the longer wavelength side, and red light emission with good chromaticity is obtained. On the other hand, when the dope concentration is lowered, the spectrum shifts to the short wavelength side, and the emission color approaches yellow. When a styryl compound is used as a red light-emitting material, the doping concentration with respect to the host material is preferably 30 mol% or more, thereby realizing a red light-emitting layer with good chromaticity having an emission spectrum peak wavelength of 620 nm or more. it can. In the present embodiment, in order to realize white light emission with good chromaticity, orange light emission that is a complementary color of blue light emission from the blue light emitting layer 13D is required. That is, in order to obtain orange light emission suitable for obtaining white light emission, the dope concentration must be at least 30 mol% or less showing red light emission, and a preferable orange light emission having a peak wavelength of emission spectrum of 590 nm or less. In order to obtain this, it is necessary to make it 10 mol% or less.

  Further, in order to obtain efficient energy transfer from the host material, the doping concentration of the guest material needs to be a certain level or more, and the doping concentration of the styryl compound is preferably 1 mol% or more.

  The blue light-emitting layer 13D is configured by appropriately selecting and mixing or laminating a blue light-emitting material, an electron transport material, a hole transport material, and both charge transport materials. The blue light emitting layer 13D preferably has an electron transporting property. Thereby, some of the electrons injected from the electron transport layer 12E into the blue light emitting layer 13D contribute to blue light emission in the blue light emitting layer 13D, and the rest are transported to the orange light emitting layer 13C to contribute to orange light emission. .

  As the blue light emitting material, for example, 9,10-di- (2-naphthyl) anthracene (ADN) represented by Chemical formula 13 can be given.

  The electron transport layer 13E on the blue light-emitting layer 13D is a layer designed to efficiently transport electrons, and in order to improve the electron transport performance, a mixture of a plurality of types of electron transport materials or a stacked layer is used. Those are preferred.

  Examples of the electron transport material include 8-hydroxyquinoline aluminum (Alq3), 8-hydroxymethylquinoline aluminum, anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, butadiene, coumarin, acridine, stilbene, and derivatives thereof. However, it is not limited to these.

The electron injection layer 13F is selected from an alkali metal compound or an alkaline earth metal compound, and is made of, for example, LiF, Li ₂ O, MgF ₂ , or MgO.

  The second electrode 14 is a conductive material having a small work function, for example, an active metal such as lithium (Li), magnesium (Mg), or calcium (Ca), silver (Ag), aluminum (Al), indium (Li), or the like. It is formed of an alloy with these metals or a laminate of these.

  This organic light emitting device can be manufactured, for example, as follows.

  First, the first electrode 12 made of the above-described thickness and material is formed on the substrate 11 made of the above-described material, for example, by sputtering. Next, the hole injection layer 13A, the hole transport layer 13B, the orange light emitting layer 13C, the blue light emitting layer 13D, the electron transport layer 13E, and the electron injection layer 13F made of the above-described thickness and material are formed by, for example, vacuum deposition. Films are sequentially formed from the electrode 12 side. After the organic layer 13 is formed, the second electrode 14 made of the above-described thickness and material is formed by, for example, vacuum deposition. Thereby, the organic light emitting device shown in FIG. 1 is formed.

  In this organic light emitting device, when a predetermined voltage is applied between the first electrode 12 and the second electrode 14, current is injected into the orange light emitting layer 13C and the blue light emitting layer 13D, respectively, and holes and electrons are generated. By recombination, orange light emission occurs in the orange light emitting layer 13C and blue light emission occurs in the blue light emitting layer 13D, and white light of the mixed color passes through the first electrode 12 and the substrate 11 and is extracted (bottom emission). Here, since the orange light emitting layer 13C is doped with a red light emitting material composed of a styryl compound represented by Chemical Formula 14 at a low concentration, orange light emission can be obtained, which is combined with the blue light emission of the blue light emitting layer 13D. Thus, white light with high color purity and luminous efficiency can be obtained. In particular, when the content of the styryl compound with respect to the host material is 10 mol% or less, preferred orange light emission with a peak wavelength of the emission spectrum of 590 nm or less can be obtained, and white light with higher color purity and light emission efficiency can be obtained. Can do.

  As described above, in the present embodiment, the guest material in the orange light emitting layer 13C is a red light emitting material made of a styryl compound, and the content of the host material is set to a low concentration to obtain orange light emission complementary to blue. Since it did in this way, color purity and luminous efficiency can be improved and reliability improves.

(Second Embodiment)
FIG. 2 shows a configuration of a so-called top emission type organic light emitting device according to the second embodiment of the present invention. Since the basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted. In this organic light emitting device, light generated in the orange light emitting layer 13C and the blue light emitting layer 13D is extracted from the second electrode 14 side using a resonator structure.

  In the present embodiment, the first electrode 12 also functions as a reflective layer, and it is desirable to increase the luminous efficiency to have as high a reflectance as possible. Examples of the material constituting the first electrode 12 include a simple substance or an alloy of a metal element such as platinum (Pt), gold (Au), silver (Ag), chromium (Cr), or tungsten (W). The thickness of the first electrode 12 is preferably 100 nm or more and 300 nm or less. The first electrode 12 may have a single layer structure or a stacked structure of a plurality of layers.

  On the other hand, the second electrode 14 has a thickness of 5 nm to 50 nm, for example, and is made of a simple substance or an alloy of a metal element such as aluminum (Al), magnesium (Mg), calcium (Ca), or sodium (Na). Yes. Among these, an alloy of magnesium and silver (MgAg alloy) is preferable.

  The second electrode 14 also functions as a semi-transmissive reflective layer. That is, in this organic light emitting device, the end surface of the first electrode 12 on the orange light emitting layer 13C side is the first end P1, the end surface of the second electrode 14 on the blue light emitting layer 13D side is the second end P2, and the organic layer 13 Has a resonator structure, and the light generated in the orange light emitting layer 13C and the blue light emitting layer 13D is resonated and extracted from the second end P2 side. With such a resonator structure, light generated in the orange light emitting layer 13C and the blue light emitting layer 13D causes multiple interference, and acts as a kind of narrow band filter, thereby reducing the half width of the spectrum of the extracted light. Color purity can be improved. In addition, external light incident from the second electrode 14 side can also be attenuated by multiple interference, and the reflectance of external light in the organic light emitting device can be extremely reduced.

  For this purpose, the optical distance L between the first end P1 and the second end P2 of the resonator is set to satisfy Equation 1, and the resonance wavelength of the resonator (the peak wavelength of the spectrum of the extracted light) and It is preferable to match the peak wavelength of the spectrum of light to be extracted. In practice, the optical distance L is preferably selected so as to be a positive minimum value satisfying Equation 1.

（式中、Ｌは第１端部Ｐ１と第２端部Ｐ２との間の光学的距離、Φは第１端部Ｐ１で生じる反射光の位相シフトΦ１ と第２端部Ｐ２で生じる反射光の位相シフトΦ２ との和（Φ＝Φ１ ＋Φ２ ）（ｒａｄ）、λは第２端部Ｐ２の側から取り出したい光のスペクトルのピーク波長、ｍはＬが正となる整数をそれぞれ表す。なお、数１においてＬおよびλは単位が共通すればよいが、例えば（ｎｍ）を単位とする。）

(Where L is the optical distance between the first end P1 and the second end P2, and Φ is the phase shift Φ1 of the reflected light generated at the first end P1 and the reflected light generated at the second end P2. (Λ = φ1 + Φ2) (rad), λ is the peak wavelength of the spectrum of light desired to be extracted from the second end portion P2, and m is an integer for which L is positive. In Equation 1, L and λ may have the same unit. For example, the unit is (nm).)

  In this organic light emitting device, when a predetermined voltage is applied between the first electrode 12 and the second electrode 14 and light is emitted from each of the orange light emitting layer 13C and the blue light emitting layer 13D, the light of each color is transmitted to the first end P1. And the second end P2 are reflected multiple times, transmitted through the second electrode 14 and extracted as white light (top emission). Also in the present embodiment, since the orange light emitting layer 13C and the blue light emitting layer 13D are the same as those in the first embodiment, white light with high color purity and luminous efficiency is generated.

  As described above, in this embodiment, the resonator structure is provided so that the light generated in the orange light emitting layer 13C and the blue light emitting layer 13D resonates between the first end P1 and the second end P2. The generated light can be subjected to multiple interference to act as a kind of narrow band filter. Therefore, the half width of the spectrum of the extracted light can be reduced, and the color purity can be improved. Furthermore, external light incident from the second electrode 14 side can also be attenuated by multiple interference, and the reflectance of external light in the organic light-emitting element can be made extremely small. Therefore, the contrast can be further improved.

(Third embodiment)
FIG. 3 shows a configuration of an organic light emitting device according to the third embodiment of the present invention. In this organic light emitting device, the first electrode 12 has a structure in which an adhesion layer 12A, a reflective layer 12B, and a barrier layer 12C are laminated in this order from the substrate 11 side. The reflective layer 12B, the barrier layer 12C, Is the same as the organic light-emitting device described in the second embodiment except that the interface is the first end P1 of the resonator. Therefore, the same components are denoted by the same reference numerals and description thereof is omitted.

  The adhesion layer 12A prevents the reflective layer 12B from peeling from the substrate 11, and has a thickness of 5 nm to 50 nm, for example, 20 nm in the present embodiment, and is composed of indium (In) and tin (Sn). And a compound containing oxygen (O) (ITO; Indium Tin Oxide).

  The reflective layer 12B reflects light generated in the light emitting layer. For example, the reflective layer 12B has a thickness of 50 nm or more and 200 nm or less, and is 200 nm in the present embodiment, for example, to reduce the light absorption loss and increase the reflectance. , Silver (Ag) or an alloy containing silver.

  The barrier layer 12C is for adjusting the optical distance L between the first end P1 and the second end P2 by changing the thickness thereof. The barrier layer 12C prevents the silver or silver-containing alloy constituting the reflective layer 12B from reacting with oxygen or sulfur components in the air, and also in the manufacturing process after forming the reflective layer 12B. 12B has a function as a protective film that alleviates damage. The barrier layer 12C is made of a material transparent to the light generated in the orange light emitting layer 13C and the blue light emitting layer 13D, for example, ITO, and the thickness thereof is the first end P1 and the second end P2 in the organic light emitting element. Is set according to the optical distance L between the two.

  This organic light emitting device can be manufactured, for example, as follows.

  First, the adhesion layer 12A, the reflective layer 12B, and the barrier layer 12C made of the above-described thickness and material are sequentially formed on the substrate 11 made of the above-described material by, for example, DC sputtering, and then the barrier layer is formed using, for example, a lithography technique. 12C, the reflective layer 12B, and the adhesion layer 12A are etched. Thereby, the first electrode 12 is formed. Subsequently, the organic layer 13 and the second electrode 14 are sequentially formed. Thereby, the organic light emitting device shown in FIG. 3 is formed.

  Since the effect of this organic light emitting element is the same as that of the second embodiment, the description thereof is omitted.

(Fourth embodiment)
FIG. 4 shows a configuration of a display device according to the fourth embodiment of the present invention. In this embodiment, white light emitted from the organic light emitting element is modulated into three color lights of R (red), G (green), and B (blue) to perform color display. In this display device, the organic light-emitting elements shown in FIG. 3 are provided in a matrix on a substrate 11 via a driving element such as a TFT (Thin Film Transistor) (not shown) and a planarizing film. is there. The organic light emitting elements are separated from each other by an insulating film 15 for each element corresponding to R (red), G (green), and B (blue). On the side of the substrate 11 where the organic light emitting element is provided, a counter substrate 20 made of a material such as glass that is transparent to light (white light) generated by the organic light emitting element is disposed. The counter substrate 20 is provided with color filters 21R, 21G, and 21B and a reflected light absorbing film 22 as a black matrix.

  In the present embodiment, the first electrode 12 is formed corresponding to each element, the organic layer 13 and the second electrode 14 are formed in common to all organic light emitting elements, and the thickness of the organic layer 13 is All elements are equal.

  The barrier layer 12C of the first electrode 12 has thicknesses dR, dG, and dB adjusted according to the emission color of the organic light emitting element. Thereby, even if the thickness of the organic layer 13 is the same in all the organic light emitting elements, the distance between the first end P1 and the second end P2 depends on the peak wavelength λ of the spectrum of light desired to be extracted from each organic light emitting element. The optical distances LR, LG, and LB are adjusted, and light in the target red, green, or blue wavelength region out of the white light generated in the orange light emitting layer 13C and the blue light emitting layer 13D is extracted from the second electrode 14 side. It is supposed to be.

  The insulating film 15 is for ensuring the insulation between the first electrode 12 and the second electrode 14 and for accurately setting the shape of the light emitting region in the organic light emitting device to a desired shape. The insulating film 15 has a thickness of about 600 nm, for example, and is made of an insulating material such as silicon dioxide (SiO2). The insulating film 15 is provided with an opening 15A corresponding to the light emitting region.

  This display device can be manufactured, for example, as follows.

  First, the reflected light absorption film 22 made of the above-described material is formed on the counter substrate 20 made of the above-described material, and is patterned into a shape as shown in FIG. Next, a red filter 21R is formed on the counter substrate 20 by applying a material for the red filter 21R by spin coating or the like, and patterning and baking by a photolithography technique. Subsequently, similarly to the red filter 21R, a blue filter 21B and a green filter 21G are sequentially formed.

  Further, the first electrode 12 is formed on the substrate 11 made of the above-described material in the same manner as in the third embodiment. At this time, the thickness of the barrier layer 12C is adjusted according to the optical distance L between the first end P1 and the second end P2, for example, by etching. Next, the insulating film 15 is formed with the above-described thickness between the first electrodes 12 by, for example, a CVD (Chemical Vapor Deposition) method, and a portion corresponding to the light emitting region is formed by using, for example, a lithography technique. The openings 15A are formed by selective removal.

  Subsequently, the hole injection layer 13A, the hole transport layer 13B, the orange light emission layer 13C, the blue light emission layer 13D, the electron transport layer 13E, and the electron injection layer 13F made of the above-described thickness and material are formed by, for example, vacuum deposition. Films are formed in this order from the one electrode 12 side to form the organic layer 13. The organic layer 13 is formed on almost the entire surface of the substrate 11. After forming the organic layer 13, the second electrode 14 made of the above-described thickness and material is formed, for example, by vapor deposition. Also in this case, the second electrode 14 is formed on almost the entire surface of the substrate 11. After that, the substrate 11 and the counter substrate 20 are arranged to face each other and sealed with, for example, an adhesive layer (not shown). Thereby, the display apparatus shown in FIG. 4 is completed.

  In this display device, white light generated in the orange light-emitting layer 13C and the blue light-emitting layer 13D corresponds to the target red and green colors according to the optical distance L between the first end P1 and the second end P2, respectively. Alternatively, the light is modulated in the blue wavelength region, and only the light of each color is multiple-reflected between the first end P1 and the second end P2, and the second electrode 14 and further the color filters 21R, 21G, and 21B and the counter substrate 20 are reflected. Is taken out through. Here, since the orange light emitting layer 13C described in the above embodiment is provided, the light emission efficiency is increased and the color purity of red, blue, and green is increased.

  As described above, in the display device of this embodiment, color display can be performed by light in the wavelength range of red, green, or blue with high color purity.

  Further, specific embodiments of the present invention will be described in detail.

(Examples 1-14)
An organic light emitting device provided with the orange light emitting layer and the blue light emitting layer of the first embodiment was produced. At that time, the host material of the orange light emitting layer 13C was α-naphthylphenyldiamine (α-NPD) represented by Chemical Formula 12, and the styryl compound (Chemical Formula 25 to Chemical Formula 38) shown in Table 1 was doped as a guest material. . FIG. 5 shows an example of the emission spectrum.

(Examples 15 to 28)
An organic light emitting device having an orange light emitting layer and a blue light emitting layer was produced in the same manner as in the first embodiment. At that time, a mixture of α-naphthylphenyldiamine (α-NPD) represented by Chemical Formula 12 and ADN of Chemical Formula 13 in a ratio of 4: 1 was used as the host material of the orange light emitting layer 13C, and styryl shown in Table 2 was used. The compound (Chemical Formula 25 to Chemical Formula 38) was doped as a guest material. FIG. 6 shows an example of the emission spectrum.

  In any of the examples, good white light emission with CIE chromaticity (0.28, 0.32) could be obtained.

Although the present invention has been described with the embodiment and the examples, the present invention is not limited to the beauty on SL embodiment Oyo the above embodiment, and various modifications may be made. For example, the material and thickness of each layer other than the orange light-emitting layer 13C in the above embodiment and the examples, or the film forming method and film forming conditions are not limited, and may be other materials and thicknesses, or Other film forming methods and film forming conditions may be used.

  In the fourth embodiment, the resonator structure is adopted. However, the resonator structure may be omitted, and color display may be performed using only the color filters 21R, 21G, and 21B.

  In addition, for example, in the third and fourth embodiments, the material of the adhesion layer 12A and the barrier layer 12C is not limited to the above-described ITO. For example, indium (In), tin (Sn), and zinc ( A metal compound or a conductive oxide containing at least one element selected from the group consisting of Zn), specifically, ITO, IZO, indium oxide (In2O3), tin oxide (SnO2), and zinc oxide (ZnO) It may be at least one member of the group consisting of Further, the material of the adhesion layer 12A is not necessarily transparent.

  Furthermore, for example, in the above embodiment, the case where the first electrode 12 is an anode and the second electrode 14 is a cathode has been described. However, the anode and the cathode are reversed, and the first electrode 12 is a cathode and the second electrode. 14 may be an anode.

It is sectional drawing showing the structure of the organic light emitting element which concerns on the 1st Embodiment of this invention. It is sectional drawing showing the structure of the organic light emitting element which concerns on the 2nd Embodiment of this invention. It is sectional drawing showing the structure of the organic light emitting element which concerns on the 3rd Embodiment of this invention. It is sectional drawing showing the structure of the display apparatus which concerns on the 4th Embodiment of this invention. It is a figure showing the emission spectrum of the Example of this invention. It is a figure showing the emission spectrum of the other Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Board | substrate, 12 ... 1st electrode, 12A ... Adhesion layer, 12B ... Reflection layer, 12C ... Barrier layer, 13 ... Organic layer, 13A ... Hole injection layer, 13B ... Hole transport layer, 13C ... Orange light emitting layer, 13D ... Blue light emitting layer, 13E ... Electron transport layer, 13F ... Electron injection layer, 14 ... Second electrode, 15 ... Insulating film, 15A ... Opening, 20 ... Counter substrate, 21R ... Red filter, 21G ... Green filter, 21B ... blue filter, 22 ... reflected light absorption film, P1 ... first end, P2 ... second end

Claims (7)

An organic layer including at least an orange light emitting layer and a blue light emitting layer is provided between the first electrode and the second electrode,
The orange light emitting layer is
9,10-di- (2-naphthyl) anthracene (ADN) represented by Chemical Formula 1, or 9,10-di- (2-naphthyl) anthracene (ADN) represented by Chemical Formula 1 and a hole transport material An organic light-emitting device comprising a host material composed of a mixture and a guest material composed of a styryl compound represented by Chemical Formula 2 .

(In Chemical Formula 2 , X represents any one of the groups shown in Chemical Formulas 3 to 9 , and Y represents any of the groups shown in Chemical Formulas 10 to 12. )

(In Chemical Formula 3 , at least one of R ¹ to R ⁵ is a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and an alkoxyl group which may have a substituent. Represents a group selected from the above, and they may be the same or different.)

(In the chemical formulas 4 to 9 , R ⁶ to R ⁵⁵ have a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and a substituent. Represents a group selected from good alkoxyl groups, which may be the same or different.)

(In Formula 10 , Z ¹ and Z ² represent a group selected from a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent, and they are the same. Or different.)

(In the chemical formulas 11 and 12 , R ⁵⁶ to R ⁷² are a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or an alkoxyl group which may have a substituent. Represents a group selected from a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, which may be the same or different.) The organic light emitting element according to claim 1, wherein a content rate of the guest material in the orange light emitting layer with respect to the host material is 10 mol% or less. The organic light-emitting device according to claim 1, wherein the hole transport material is α-naphthylphenyldiamine (α-NPD) represented by Chemical formula 13.

It has a resonator structure that resonates light generated in the organic layer between a first end and a second end, and an optical distance L between the first end and the second end is The organic light-emitting device according to claim 1, wherein Equation 1 is satisfied.

(In Equation 1, L is the optical distance between the first end and the second end, λ is the peak wavelength of the spectrum of the light to be extracted, Φ is the phase shift Φ1 of the reflected light generated at the first end, and The sum (Φ = Φ1 + Φ2) (rad) of the phase shift Φ2 of the reflected light generated at the second end portion, and m represents an integer for which L is positive. An organic light emitting device having an organic layer including at least an orange light emitting layer and a blue light emitting layer between the first electrode and the second electrode,
The orange light emitting layer of the organic light emitting element is
9,10-di- (2-naphthyl) anthracene (ADN) represented by Chemical formula 14 or 9,10-di- (2-naphthyl) anthracene (ADN) represented by Chemical formula 14 and a hole transport material A display device comprising: a host material made of a mixture; and a guest material made of a styryl compound represented by Chemical formula 15 .

(In the chemical formula 15 , X represents any of the groups shown in chemical formulas 16 to 22 , and Y represents any of the groups shown in chemical formulas 23 to 25. )

(In the chemical formula 16 , at least one of R ¹ to R ⁵ is a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and an alkoxyl group which may have a substituent. Represents a group selected from the above, and they may be the same or different.)

(In the chemical formulas 17 to 22 , R ⁶ to R ⁵⁵ have a hydrogen atom, a halogen atom, a nitro group, a cyano group, a trifluoromethyl group, an alkyl group which may have a substituent, and a substituent. Represents a group selected from good alkoxyl groups, which may be the same or different.)

(In the formula 23 , Z ¹ and Z ² represent a group selected from a hydrogen atom, an alkyl group which may have a substituent, and an aryl group which may have a substituent, and they are the same. Or different.)

(In the chemical formulas 24 and 25 , R ⁵⁶ to R ⁷² are a hydrogen atom, an alkyl group which may have a substituent, an aryl group which may have a substituent, or an alkoxyl group which may have a substituent. Represents a group selected from a halogen atom, a nitro group, a cyano group and a trifluoromethyl group, which may be the same or different.) The display device according to claim 5 , wherein a content rate of the guest material in the orange light emitting layer with respect to the host material is 10 mol% or less. The display device according to claim 5, further comprising a color filter that transmits light generated in the organic layer.

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