JP2011108531A - Display device and electronic equipment - Google Patents

Abstract

The present invention provides a display device capable of improving the light emission efficiency and extending the life while improving the manufacturing yield of the display device, and an electronic device including the display device and having excellent reliability. .
A display device 100 includes light emitting elements 1 _R , 1 _G , 1 _B and a color filter 102 including filter portions 19 _R , 19 _G , 19 _B, and the light emitting elements 1 _R , 1 _G , 1 _B is in contact with the anode 3 between the anode 12 and the light emitting portion, and the light emitting portion including a plurality of light emitting layers provided between the cathode 12, the anode 3, and the cathode 12 and the anode 3, respectively. provided, and a hole injection layer _{4 R,} 4 G, _{4 B} having a hole injecting property, hole injection and hole injection layer _{4 R} of the light-emitting element _{1 R} light emitting element ₁ G, _{1 B} in The degree of hole injecting property between the layers 4 _G and 4 _B is made different from each other, and thereby the light emitting characteristics of the light emitting element 1 _{R and} the light emitting elements 1 _G and 1 _B are made different from each other.
[Selection] Figure 1

Description

  The present invention relates to a display device and an electronic apparatus.

  An organic electroluminescence element (so-called organic EL element) is a light emitting element having a structure in which at least one light emitting organic layer (light emitting layer) is interposed between an anode and a cathode. In such a light emitting device, by applying an electric field between the cathode and the anode, electrons are injected into the light emitting layer from the cathode side and holes are injected from the anode side, and electrons and holes are injected into the light emitting layer. Recombination generates excitons, and when the excitons return to the ground state, the energy is emitted as light.

Such a light emitting element has, for example, a structure in which three light emitting layers corresponding to three colors of R (red), G (green), and B (blue) are laminated between a cathode and an anode. In addition, it is known that the three light emitting layers as a whole emit white light (see, for example, Patent Document 1). Such a light-emitting element that emits white light displays a full-color image by being used in combination with a color filter having three color filter portions of R (red) pixels, G (green) pixels, and B (blue) pixels. Can do.
In such a display device in which a white light emitting element and a color filter are combined, each light emitting element has a plurality of light emitting layers. Therefore, the life of the light emitting element can be extended, and the life of the display apparatus can be extended. it can.

In such a display device, a light emitting element is provided corresponding to each of the R pixel, the G pixel, and the B pixel. However, since a plurality of light emitting elements can have the same configuration, the light emitting element is formed for each pixel. There is no need to coat the film material separately, which facilitates production. As a result, the manufacturing yield of the display device can be improved.
However, in the conventional display device, since the layer configuration between the anode and the cathode of the plurality of light emitting elements is exactly the same, the amount of light blocked by the filter unit among the light from the light emitting elements in each pixel There were many. Therefore, there is a problem that the light emission efficiency of the display device is lowered, and as a result, the power consumption of the display device is increased.

JP 2003-77681 A

  An object of the present invention is to provide a display device capable of achieving high luminous efficiency and long life while improving the manufacturing yield of the display device, and an electronic device having the display device and excellent in reliability. It is to provide.

Such an object is achieved by the present invention described below.
The display device of the present invention includes a first light emitting element and a second light emitting element provided on one surface side of the substrate,
A first filter portion that transmits light of a first color out of light from the first light emitting element, and a second color different from the first color among light from the second light emitting element. A color filter including a second filter unit that transmits the light of
The first light emitting element and the second light emitting element are respectively
A cathode,
The anode,
A light emitting section provided between the cathode and the anode, and comprising a plurality of light emitting layers that emit light in different colors by energization between the two electrodes;
A hole injection layer provided between the anode and the light emitting portion so as to be in contact with the anode and having a hole injection property;
The hole injecting layers of the first light emitting element and the hole injecting layer of the second light emitting element have different degrees of hole injecting property, whereby the light emitting portion of the first light emitting element and the The light emitting characteristics of the second light emitting element are different from each other.

  Thereby, even if the layer configurations of the first light-emitting element and the second light-emitting element are the same as each other in the layers other than the hole injection layer, the emission spectrum of the light-emitting portion of the first light-emitting element and the second light-emitting element The emission spectrum of the light emitting part can be made different. Therefore, while making the first light emitting element and the second light emitting element easy to manufacture, the emission spectrum of the light emitting part of the first light emitting element is suitable for transmission through the first filter part, The emission spectrum of the light emitting part of the second light emitting element can be made suitable for transmission through the second filter part.

Further, in each of the first light-emitting element and the second light-emitting element, the light-emitting portion includes a plurality of light-emitting layers, and therefore, the portions that contribute to the light emission of the light-emitting portion (specifically, the light-emitting layer and the light-emitting layer are adjacent to each other) The number of the vicinity of the interface between the layers can be adjusted by the kind of the hole injection material. Therefore, the light emission efficiency is improved, the required current can be suppressed, and the load on the light emitting portions of the first light emitting element and the second light emitting element can be suppressed. As a result, deterioration of the first light-emitting element and the second light-emitting element can be prevented or suppressed, and the lifetime of the first light-emitting element and the second light-emitting element can be extended.
For these reasons, it is possible to improve the light emission efficiency and extend the life of the display device while improving the manufacturing yield of the display device.

In the display device of the present invention, it is preferable that the hole injection layer of the first light emitting element is made of a material different from that of the hole injection layer of the second light emitting element.
Thereby, the degree of the hole injection property of the hole injection layer of the first light emitting element and the hole injection layer of the second light emitting element can be made different from each other.
In the display device of the present invention, the hole mobility of the material constituting the hole injection layer of the first light emitting element is higher than the hole mobility of the material constituting the hole injection layer of the second light emitting element. Is preferably small.
Accordingly, the distribution of the light emitting region (region where holes and electrons recombine) in the light emitting portion of the first light emitting element is changed to the light emitting region (region where holes and electrons recombine in the second light emitting device). ) Distribution to the anode side. As a result, the light emission characteristics (light emission spectra) of the light emitting part of the first light emitting element and the light emitting part of the second light emitting element can be made different from each other.

In the display device of the present invention, the hole mobility of the material constituting the hole injection layer of the first light emitting element, and the hole mobility of the material constituting the hole injection layer of the second light emitting element, The difference is preferably 10 ² cm ² / Vs or more.
Accordingly, the distribution of the light emitting region (region where holes and electrons recombine) in the light emitting portion of the first light emitting element is changed to the light emitting region (region where holes and electrons recombine in the second light emitting device). ) Distribution to the anode side relative to the distribution. As a result, the light emission characteristics (light emission spectra) of the light emitting part of the first light emitting element and the light emitting part of the second light emitting element can be clearly made different from each other.

In the display device of the present invention, it is preferable that a hole injection layer of at least one of the first light emitting element and the second light emitting element includes a benzidine derivative.
Benzidine derivatives have excellent hole injection properties. In addition, benzidine derivatives have various hole mobility within a range where the hole injection property can be improved. Therefore, the hole injection layer of at least one of the first light-emitting element and the second light-emitting element includes a benzidine derivative, so that a desired hole mobility can be relatively easily obtained. It can have.
In the display device of the present invention, the benzidine derivative is preferably a material having an N, N, N ′, N′-tetraarylbenzidine skeleton.
Such a benzidine derivative has an extremely excellent hole injection property.

In the display device of the present invention, it is preferable that the hole injection layer of the second light emitting element includes an ionic material.
The ionic material is a material having excellent hole injectability, excellent conductivity, and extremely high hole mobility. Therefore, in the second light-emitting element, the hole injection layer configured to contain an ionic material injects holes to the cathode side well, while the light-emitting region in the light-emitting portion (holes and electrons recombine). The distribution of the region) can be shifted to the cathode side.

In the display device of the present invention, the ionic material is preferably PEDOT / PSS.
As a result, in the second light emitting device, the hole injection layer injects positive holes to the cathode side, and the distribution of the light emitting regions (regions in which holes and electrons recombine) in the light emitting portion is made closer to the cathode side. It can be shifted reliably.

In the display device of the present invention, it is preferable that the average thickness of the hole injection layer of the first light emitting element is equal to the average thickness of the hole injection layer of the second light emitting element.
Accordingly, the hole injection layer of the first light emitting element and the hole injection layer of the second light emitting element can be formed under the same film forming conditions or conditions close thereto. As a result, the manufacturing of the display device can be simplified.

In the display device of the present invention, it is preferable that the average thickness of the hole injection layer of the first light emitting element is different from the average thickness of the hole injection layer of the second light emitting element.
Accordingly, the hole injection properties of the hole injection layer of the first light emitting element and the hole injection layer of the second light emitting element can be made different from each other.
In the display device of the present invention, it is preferable that each of the first light emitting element and the second light emitting element has a top emission structure.
Thereby, in the first light emitting element and the second light emitting element, the light generated in the light emitting part is amplified by resonance. Therefore, the luminance of the display device can be increased. Further, in the light emitting element having the top emission structure, light is extracted from the cathode side (the side opposite to the substrate), so that it is possible to prevent an optical defect or the like from occurring due to a difference in the material of the hole injection layer.
In the display device according to the aspect of the invention, it is preferable that the first light-emitting element and the second light-emitting element have the same material constituting each layer other than the hole injection layer.
Thereby, the manufacture of the display device can be simplified.

In the display device of the present invention, the display device includes a third light emitting element disposed on one surface side of the substrate,
The color filter includes a third filter unit that converts light from the third light emitting element into a third color different from the first color and the second color,
The third light emitting element is:
A cathode,
The anode,
A light-emitting unit that is provided between the cathode and the anode and includes a plurality of light-emitting layers that emit light when energized therebetween;
A hole injection layer provided between the anode and the light-emitting portion so as to be in contact with the anode and configured to include a hole injection material;
The hole injecting material contained in the hole injecting layer of the third light emitting element is preferably different from the hole injecting material contained in the hole injecting layer of the first light emitting element.
As a result, for example, in a display device having R pixels, G pixels, and B pixels and capable of full color display, the display device can be manufactured at a high yield and the lifetime can be increased while improving the manufacturing yield. be able to.

In the display device of the present invention, it is preferable that the material constituting the hole injection layer of the third light emitting element is the same as the material constituting the hole injection layer of the second light emitting element.
Thereby, the manufacture of the display device can be simplified.
In the display device of the present invention, it is preferable that the material constituting the hole injection layer of the third light emitting element is different from the material constituting the hole injection layer of the second light emitting element.
Thereby, the emission spectrum of the light emitting part of the third light emitting element is made suitable for transmission through the third filter part, and the light emission efficiency of the display device can be increased.

In the display device of the present invention, the first color is red, the second color is blue, and the third color is green.
Each of the light emitting portions of the first light emitting element, the second light emitting element, and the third light emitting element has a red light emitting layer, a blue light emitting layer, and a green light emitting layer stacked in this order from the anode side to the cathode side. It is preferable that
Thereby, a display device capable of full color display can be provided.
An electronic apparatus according to the present invention includes the display device according to the present invention.
Such an electronic device has excellent reliability.

It is typical sectional drawing which shows the display apparatus (display apparatus) concerning embodiment of this invention. It is a figure which shows typically the longitudinal cross-section of the light emitting element (1st light emitting element) with which the display apparatus shown in FIG. 1 was equipped. It is typical sectional drawing for demonstrating an example of the manufacturing method of the display apparatus shown in FIG. It is typical sectional drawing for demonstrating an example of the manufacturing method of the display apparatus shown in FIG. 1 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which an electronic apparatus of the present invention is applied. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) to which the electronic device of this invention is applied. It is a perspective view which shows the structure of the digital still camera to which the electronic device of this invention is applied. (A) is a figure which shows the light emission spectrum of the 1st light emitting element of the Example of this invention, (b) is a figure which shows the light emission spectrum of a 2nd light emitting element, (c) is a light emitting element of a comparative example. It is a figure which shows the emission spectrum of.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a display device and an electronic apparatus of the invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic sectional view showing a display device (display device) according to an embodiment of the present invention, and FIG. 2 is a diagram schematically showing a longitudinal section of a light emitting element provided in the display device shown in FIG. is there. In the following description, for convenience of explanation, the upper side in FIG. 1 and FIG. 2 will be described as “upper” and the lower side as “lower”.

(Display device)
A display device 100 illustrated in FIG. 1 includes a plurality of light emitting elements 1 _R , 1 _G , 1 _B (first light emitting element 1 _R , second light emitting element 1 _G, and third light emitting element 1 _B ). 101 and a color filter 102 including filter units 19 _R , 19 _G , and 19 _B provided corresponding to the light emitting elements 1 _R , 1 _G , and 1 _B , respectively.
The light emitting device 101 and the color filter 102 are bonded via a resin layer 45 made of a thermosetting resin such as an epoxy resin.

In such a display device 100, a plurality of light emitting elements 1 _R , 1 _G , 1 _B and a plurality of filter units 19 _R , 19 _G , 19 _B are provided corresponding to the sub-pixels 100 _R , 100 _G , 100 _B. It constitutes a display panel with a top emission structure.
In the present embodiment, an example in which an active matrix method is employed as a display device driving method will be described. However, a passive matrix method may be employed.

The light emitting device 101 includes a substrate 21, a plurality of light emitting elements 1 _R , 1 _G , 1 _B, and a plurality of switching elements 24.
The substrate 21 supports the plurality of light emitting elements 1 _R , 1 _G , 1 _B and the plurality of switching elements 24. Each light emitting element 1 _R , 1 _G , 1 _B of the present embodiment has a configuration for extracting light from the side opposite to the substrate 21 (top emission type). Accordingly, the substrate 21 can be either a transparent substrate or an opaque substrate. In the case where the light-emitting elements 1 _R, 1 _G, 1 _B is a structure in which light is extracted from the substrate 21 side (bottom emission type), the substrate 21 is substantially transparent (colorless and transparent, colored transparent or semi-transparent ). The light emitting elements 1 _R , 1 _G , and 1 _B will be described in detail later.

Since the light emitting elements 1 _R , 1 _G , and 1 _B each have a top emission structure as described above, the light emitted from the light emitting unit 16 described later resonates in the light emitting elements 1 _R , 1 _G , and 1 _B , respectively. Is amplified. Therefore, the luminance of the display device 100 can be increased. Further, in the light emitting elements 1 _R , 1 _G , 1 _{B having} the top emission structure, light is extracted from the side opposite to the substrate 21 (the cathode 12 side described later), and therefore the difference in the material and the like of the hole injection layer 4 as described later. Therefore, it is possible to prevent optical defects (unintentional phenomena other than changes in the emission spectrum) and the like.

  When the substrate 21 is a transparent substrate, examples of the constituent material of the substrate 21 include polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate. Examples thereof include resin materials, glass materials such as quartz glass and soda glass, and one or more of them can be used in combination.

Examples of the opaque substrate include a substrate made of a ceramic material such as alumina, an oxide film (insulating film) formed on the surface of a metal substrate such as stainless steel, and a substrate made of a resin material. It is done.
Although the average thickness of such a board | substrate 21 is not specifically limited, It is preferable that it is about 0.1-30 mm, and it is more preferable that it is about 0.1-10 mm.

On such a substrate 21, a plurality of switching elements 24 are arranged in a matrix.
Each switching element 24 is provided corresponding to the respective light emitting elements _{1 R, 1 G, 1 B} , a driving transistor for driving the light emitting elements _{1 R, 1 G, 1 B} .
Each switching element 24 includes a semiconductor layer 241 made of silicon, a gate insulating layer 242 formed on the semiconductor layer 241, a gate electrode 243 formed on the gate insulating layer 242, a source electrode 244, And a drain electrode 245.

A planarizing layer 22 made of an insulating material is formed so as to cover the plurality of switching elements 24.
On the planarization layer 22, light emitting elements 1 _R , 1 _G , 1 _B are provided corresponding to the switching elements 24.
The light emitting element 1 _R is configured by laminating a reflective film 42, a corrosion preventing film 43, an anode 3, a laminate (organic EL light emitting unit) 15, a cathode 12, and a cathode cover 44 in this order on the planarizing layer 22. Yes. In the present embodiment, the anode 3 of each light emitting element 1 _R , 1 _G , 1 _B constitutes a pixel electrode and is electrically connected to the drain electrode 245 of each switching element 24 by a conductive portion (wiring) 27. . The cathode 12 of the light-emitting elements _{1 R, 1 G, 1 B} is a common electrode.
A partition wall 41 is provided between the adjacent light emitting elements 1 _R , 1 _G , 1 _B.
The color filter 102 is bonded to the light emitting device 101 configured as described above through a resin layer 45 formed of a thermosetting resin such as an epoxy resin.

The color filter 102 includes a substrate 20, a plurality of filter portions 19 _R , 19 _G , 19 _B, and a light shielding layer 36.
The substrate (sealing substrate) 20 has a function of supporting each filter portion 19 _R , 19 _G , 19 _B and the light shielding layer 36.
The filter units 19 _R , 19 _G , and 19 _B are provided corresponding to the light emitting elements 1 _R , 1 _G , and 1 _B.

Filter unit 19 _R is for converting light W _R from the light emitting element 1 _R red (first color) (transmits red light out of the light W _R). The filter unit 19 _G is used to convert the W _G from the light-emitting element 1 _G to green (second color) (transmits green light of light W _G). The filter unit 19 _B is for converting light W _B from the light-emitting element 1 _B to blue (third color) (transmits blue light among the light W _B). By using such filter units 19 _R , 19 _G , and 19 _{B in combination} with the light emitting elements 1 _R , 1 _G , and 1 _B , a full color image can be displayed.
A light shielding layer 36 is formed between adjacent filter portions 19 _R , 19 _G , 19 _B.
The light shielding layer 36 has a function of preventing unintended subpixels 100 _R , 100 _G , and 100 _B from emitting light.

The substrate (sealing substrate) 20 and the resin layer 45 have a function of sealing each of the light emitting elements 1 _R , 1 _G , 1 _B described above.
A transparent substrate is used as the substrate 20, and the constituent material of the substrate 20 is not particularly limited as long as the substrate 20 has optical transparency, and is the same as the constituent material of the substrate 21 described above. Things can be used.

(Light emitting element)
Here, the light emitting elements 1 _R , 1 _G , and 1 _B will be described in detail.
As shown in FIG. 1, each of the light emitting elements (electroluminescent elements) 1 _R , 1 _G , and 1 _B has an emission spectrum (light emitting color) between two electrodes (between the anode 3 and the cathode 12). A laminate 15 including three light emitting layers of different R (red), G (green), and B (blue) is inserted. As shown in FIG. 2, the laminate 15 (15 _R , 15 _G , 15 _B ) has a hole injection layer 4 (4 _R , 4 _G , 4 _B ) and holes from the anode 3 side to the cathode 12 side. The transport layer 5, the light emitting portion 16, the electron transport layer 10 and the electron injection layer 11 are laminated in this order. In addition, the light emitting unit 16 includes a first light emitting layer (red light emitting layer) 6, an intermediate layer 7, a second light emitting layer (blue light emitting layer) 8, and a third light emitting layer (from the anode 3 side to the cathode 12 side). Green light emitting layer) 9 are laminated in this order.

In other words, each light emitting element 1 _R , 1 _G , 1 _B includes the anode 3, the hole injection layer 4 (4 _R , 4 _G , 4 _B ), the hole transport layer 5, and the first light emitting layer 6, respectively. The intermediate layer 7, the second light emitting layer 8, the third light emitting layer 9, the electron transport layer 10, the electron injection layer 11, and the cathode 12 are laminated in this order.
In this embodiment, a reflective film 42 and a corrosion prevention film 43 are provided between the anode 3 and the planarizing layer 22, and a cathode cover (sealing) is provided on the opposite side of the cathode 12 from the laminate 15. Layer) 44 is provided.

In each of the light emitting elements 1 _R , 1 _G , and 1 _B , the cathode 12 side with respect to the light emitting layers of the first light emitting layer 6, the second light emitting layer 8, and the third light emitting layer 9. Electrons are supplied (injected) from, and holes are supplied (injected) from the anode 3 side. In each light emitting layer, holes and electrons recombine, and excitons (excitons) are generated by the energy released during the recombination, and energy (fluorescence or phosphorescence) is generated when the excitons return to the ground state. Is emitted (emitted).

In particular, in the display device 100, the light-emitting element ₁ a hole injection layer _{R 4} (4 _R) and the light emitting element ₁ G, ₁ degree of hole injection of the hole injection layer _{4 (4} G, _{4 B)} of _B Accordingly, the light emission characteristics of the light emitting part 16 of the light emitting element 1 _{R and} the light emitting parts 16 of the light emitting elements 1 _G and 1 _B are made different from each other.
Thereby, even if the layer configurations of the light emitting elements 1 _R , 1 _G , 1 _B are the same as each other in the layers other than the hole injection layer 4, the emission spectrum of the light emitting part 16 of the light emitting element 1 _R and the light emitting elements 1 _G , 1 B The emission spectrum of the _B light emitting portion 16 can be made different. Therefore, while making the light emitting elements 1 _R , 1 _G , and 1 _B easy, the emission spectra of the light emitting parts 16 of the light emitting elements 1 _R , 1 _G , and 1 _B are filtered with the filter parts 19 _R , 19 _G , 19 _B. It is possible to make it suitable for transmission.
It is preferable that the materials constituting each layer other than the hole injection layer 4 of the light emitting elements 1 _R , 1 _G , and 1 _B are the same. Thereby, the manufacture of the display device 100 can be simplified.

Hereinafter, it will be described in order components constituting the light-emitting element 1 _R. Hereinafter, the light emitting element 1 _R will be described as a representative. The light-emitting elements 1 _G and 1 _B will be described with a focus on matters different from the light-emitting element 1 _R, and the description of the same matters will be omitted. Further, in the following description, the light emitting elements 1 _R , 1 _G , 1 _B will be described as having the same configuration except for the configuration of the hole injection layer 4 (4 _R , 4 _G , 4 _B ).

(anode)
The anode 3 is an electrode (first electrode) that injects holes into the hole transport layer 5 via a hole injection layer 4 described later.
Moreover, as a constituent material of the anode 3, it is preferable to use a material having a large work function and excellent conductivity.

Examples of the constituent material of the anode 3 include oxides such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO, Au, Pt, and Ag. Cu, alloys containing these, and the like can be used, and one or more of these can be used in combination.
Moreover, in this embodiment, the anode 3 has a light transmittance. Thereby, the reflective film 42 can reflect the light from each light emitting layer.

The thickness of the anode 3 is preferably different from each other according to the wavelength of each emitted light of the light emitting elements 1 _R , 1 _G , and 1 _B.
More specifically, for the anode 3 of the light emitting element 1 _R , the distance L between the cathode 12 and the reflective film 42 described later corresponds to the wavelength of light emitted from the light emitting element 1 _R (red wavelength). It is preferable that the thickness is adjusted so as to be the same. Further, the thickness of the anode 3 of the light emitting element 1 _G is set so that the distance L between the cathode 12 and the reflective film 42 corresponds to the wavelength of light emitted from the light emitting element 1 _G (green wavelength). is preferable to be adjusted, also, the anode 3 for the light emitting element 1 _B, the distance L between the cathode 12 and the reflective film 42 corresponding to the wavelength of light emitted from the light emitting element 1 _B (wavelength of blue) It is preferable that the thickness is adjusted so as to be the same.

This can increase the brightness of the desired chromaticity of the light emitting element 1 _R, 1 _G, 1 each emitted light _B.
In particular, the thickness of the anode 3 depends on the distance L between the cathode 12 and the reflection film 42 by causing repeated light reflection between the cathode 12 and the reflection film 42 to cause interference (resonance). It is preferably set so that light of a wavelength can be emitted to the outside. This makes it possible to increase the strength and color purity of light emitted from the light-emitting element 1 _R. In this case, by setting the distance L between the cathode 12 and the reflective film 42 to a desired value (a value corresponding to the red wavelength), light having a desired wavelength is resonated between the cathode 12 and the reflective film 42. Can be made. More specifically, when the wavelength of the chromaticity whose luminance is desired to be increased is λ, a value considering the phase shift amount at the time of light reflection at the cathode 12 or the reflection film 42 is added to or subtracted from nλ / 2. The obtained value is defined as a distance L (where n is a natural number).
The average thickness of the anode 3 is not particularly limited, but is preferably about 10 to 200 nm, and more preferably about 20 to 150 nm.

(Hole injection layer)
The hole injection layer 4 has a function of improving the hole injection efficiency from the anode 3 (that is, hole injection property).
The constituent material of the hole injection layer 4 (hole injection material) is not particularly limited as long as the hole injection layer 4 exhibits the hole injection property as described above, and is a neutral material. Alternatively, an ionic material may be used.

As a neutral material, for example, a diaminobenzene derivative, MTDATA, a benzidine derivative, a hexaazatriphenylene derivative, or the like can be typically given, and one of these can be used alone or in combination of two or more.
Specifically, as a neutral material, for example, a compound (MTDATA) represented by the following formula (4-1), a compound (m-TPD1) represented by the following formula (4-2), and the following formula (4-3) ) (M-TPD2), a compound (HIM) represented by the following formula (4-4), a compound (TPAC) represented by the following formula (4-5), and a following formula (4-6). Compound (TPD-2), a compound (TPD-3) represented by the following formula (4-7), and the like. Among these, one can be used alone or two or more can be used in combination.

  Examples of the ionic material include PEDOT / PSS (polyethylenedioxythiophene / polystyrene sulfonic acid) represented by the following formula (4-8), polythiophene / PSS, and the like. Alternatively, two or more kinds can be used in combination.

As described above, the hole injection layer 4 _{(4 R)} of the light-emitting element _{1 R,} the light emitting element ₁ G, ₁ hole injection layer _{4 (4} G, _{4 B)} of _B and the degree of hole injection property each other Is different. Thereby, with different emission characteristics of the light emitting portion 16 of the light emitting element 1 _R and the light emitting element 1 _G, 1-emitting portion 16 of the _B together.
As a method for the degree of hole injection property different from each other between the light emitting element ₁ hole injection layer of _{R 4} (4 _R) and the light emitting element ₁ G, ₁ hole injection layer of _{B 4 (4 G, 4 B} ) is Although not particularly limited, the material, film quality, concentration, thickness, presence / absence, etc. of the hole injection layer 4 can be mentioned, and one of these can be used alone or in combination of two or more.

In particular, the light-emitting element 1 a hole injection layer _R 4 (i.e. a hole injecting layer 4 _R) is composed of a material different from the hole injection layer 4 in the light-emitting element 1 _G (i.e. the hole injection layer 4 _G) Is preferred. Thus, it is possible to vary the degree of hole injection of the hole injection layer 4 _R of the light-emitting element 1 _R and the hole injection layer 4 _G of the light-emitting element 1 _G together.
In this case, the hole mobility of the material constituting the hole injection layer 4 _R of the light emitting element 1 _R is smaller than the hole mobility of the material constituting the hole injection layer 4 _G of the light emitting element 1 _G. preferable.

Thereby, the distribution of the light emitting region (region where holes and electrons recombine) in the light emitting portion 16 of the light emitting element 1 _{R is changed to} the light emitting region (region where holes and electrons recombine in the light emitting portion 16 of the light emitting element 1 _G ). ) Distribution toward the anode 3 side. As a result, it is possible to vary the light-emitting characteristics of the light emitting portion 16 of the light emitting element 1 _R and the light emitting portion 16 of the light emitting element 1 _G (the emission spectrum) to each other.

Specifically, red stacking order as in this embodiment, when the light-emitting layer of green and blue are laminated, by shifting the light-emitting region in the light-emitting element 1 _R of the light-emitting portion 16 as described above, In the light emitting portion 16 of the light emitting element _1R, the emission of red light can be increased.
Further, when the constituent materials of the hole injection layers 4 _R and 4 _G have the relationship of hole mobility as described above, the hole mobility of the material constituting the hole injection layer 4 _R of the light emitting element 1 _R is The difference from the hole mobility of the material constituting the hole injection layer 4 _G of the light emitting element 1 _G is preferably 10 ² cm ² / Vs or more.

Thereby, the distribution of the light emitting region (region where holes and electrons recombine) in the light emitting portion 16 of the light emitting element 1 _{R is changed to} the light emitting region (region where holes and electrons recombine in the light emitting portion 16 of the light emitting element 1 _G ). ) Distribution to the anode 3 side with respect to the distribution. As a result, it is possible to vary the light-emitting characteristics of the light emitting portion 16 of the light emitting element 1 _R and the light emitting element 1 _G of the light-emitting portion 16 (the emission spectrum) clearly mutually.

Specifically, as red stacking order as in this embodiment, when the light-emitting layer of green and blue are laminated, the light-emitting region in the light-emitting element 1 _R of the light-emitting portion 16 is shifted to the anode 3 side with the state, the light-emitting region in the light-emitting element 1 _G of the light-emitting portion 16 can be brought into a state as shifted to the cathode 12 side. Thus, the enhancing the emission of red light emitting element 1 _R of the light-emitting portion 16, it is possible to enhance the emission of green light of the light emitting device 1 _G of the light-emitting portion 16.

Here, regarding the hole mobility of some of the above-described hole injection materials, for example, the hole mobility of the compound represented by the above formula (4-5) is 7 × 10 ^−3. a ^[cm 2 / Vs] C., the hole mobility of the compound represented by the above formula (4-4) is about ^{2.7 × 10 -3 [cm 2 /} Vs], the equation (4 The hole mobility of the compound represented by 1) is about 3 × 10 ⁻⁵ [cm ² / Vs].

The hole injection layer 4 of at least one of the light emitting element 1 _R and the light emitting element 1 _G preferably includes a benzidine derivative as described above.
Benzidine derivatives have excellent hole injection properties. In addition, benzidine derivatives have various hole mobility within a range where the hole injection property can be improved. Therefore, the hole injection layer 4 of at least one of the light emitting element 1 _R and the light emitting element 1 _G includes a benzidine derivative, so that the desired positive electrode as described above can be relatively easily obtained. It can have hole mobility.

The benzidine derivative may be N, N, N ′, N′-tetraarylbenzidine represented by the above formulas (4-2) to (4-4), (4-6), (4-7). A material having a skeleton is preferable. Such a benzidine derivative has an extremely excellent hole injection property.
Further, the hole injection layer 4 _G of the light-emitting element 1 _G is preferably is configured to include an ionic material as described above.

The ionic material is a material having excellent hole injectability, excellent conductivity, and extremely high hole mobility. Therefore, in the light emitting element 1 _G , the hole injection layer 4 _G configured to contain an ionic material injects holes to the cathode 12 side well, while the light emitting region 16 (holes and electrons are generated). The distribution of the region to be recombined can be shifted to the cathode 12 side.

The ionic material is preferably PEDOT / PSS as represented by the formula (4-8).
Thereby, in the light emitting element 1 _G , the hole injection layer 4 _G injects positive holes into the cathode 12 side and distributes the distribution of the light emitting region (region where holes and electrons recombine) in the light emitting unit 16. It is possible to shift more reliably on the cathode 12 side.

Further, the hole injection layer 4 average thickness of _R of the light-emitting element 1 _R may be different and equal to the average thickness of the hole injection layer 4 _G of the light-emitting element 1 _G.
When the hole injection layer 4 average thickness of _R of the light-emitting element 1 _R is equal to the average thickness of the hole injection layer 4 _G of the light-emitting element 1 _G, the hole injection layer 4 _R of the light-emitting element 1 _R light emitting element 1 _G The hole injection layer _4G can be formed under the same film formation conditions or conditions close thereto. As a result, the manufacturing of the display device 100 can be simplified.

On the other hand, if the hole injection layer 4 average thickness of _R of the light-emitting element 1 _R is different from the average thickness of the hole injection layer 4 _G of the light-emitting element 1 _G, the hole injection layer 4 _R and the light emitting elements of the light emitting element 1 _R 1 _G hole injection layer 4 The degree of hole injection with _G can be made different from each other.
Further, the hole injecting material contained in the hole injecting layer 4 _B of the light emitting element 1 _B is different from the hole injecting material contained in the hole injecting layer 4 _R of the light emitting element 1 _R.

  Thereby, the emission spectrum between the R pixel and the B pixel can be optimized similarly to the optimization of the emission spectrum between the R pixel and the G pixel as described above. Therefore, in the display device 100 that has R pixels, G pixels, and B pixels and is capable of full color display, the display device 100 is manufactured at a high yield and the light emission efficiency and the life of the display device 100 are increased. be able to.

The material constituting the hole injection layer 4 _B of the light emitting element 1 _B may be the same as or different from the material constituting the hole injection layer 4 _G of the light emitting element 1 _G.
When the material constituting the hole injection layer 4 _B of the light emitting element 1 _B is the same as the material constituting the hole injection layer 4 _G of the light emitting element 1 _G , the manufacturing of the display device 100 is simplified as described later. Can be planned.

On the other hand, if the material constituting the hole injection layer 4 _B of the light emitting device 1 _B is different from the material constituting the hole injection layer 4 _G of the light-emitting element 1 _G, the emission spectrum of the light emitting portion 16 of the light emitting element 1 _B filter and suitable for transmission parts 19 _B, it is possible to increase the luminous efficiency of the display device 100.
The average thickness of the hole injection layer 4 (4 _R , 4 _G , 4 _B ) is not particularly limited, but is preferably about 5 to 150 nm, and more preferably about 10 to 100 nm.

(Hole transport layer)
The hole transport layer 5 has a function of transporting holes injected from the anode 3 through the hole injection layer 4 (4 _R , 4 _G , 4 _B ) to the first light emitting layer 6.
As the constituent material of the hole transport layer 5, various p-type polymer materials and various p-type low-molecular materials can be used alone or in combination. For example, the hole transport layer 5 is represented by the following formula (5-1). N, N′-di (1-naphthyl) -N, N′-diphenyl-1,1′-diphenyl-4,4′-diamine (NPD), N, N′-diphenyl-N, N′-bis ( And tetraarylbenzidine derivatives such as 3-methylphenyl) -1,1′-diphenyl-4,4′-diamine (TPD), tetraaryldiaminofluorene compounds or derivatives thereof (amine compounds), and the like. These can be used alone or in combination of two or more.

The average thickness of the hole transport layer 5 is not particularly limited, but is preferably about 10 to 150 nm, and more preferably about 10 to 100 nm.
The hole transport layer 5 can be omitted depending on the configuration of the hole injection layer 4. By omitting the hole transport layer 5, the hole process of the display device 100 can be simplified. In this case, the hole injection layer 4 is in contact with both the anode 3 and the first light emitting layer 6.

(First light emitting layer)
The first light-emitting layer 6 includes a first light-emitting material that emits light in a first color and a first host material that uses the first light-emitting material as a guest material. Such a first light-emitting layer 6 can be formed, for example, by doping the first host material as a dopant with the first light-emitting material that is a guest material. Note that the first host material can be omitted.

The first light emitting material is a red light emitting material that emits red light.
Such a red light emitting material is not particularly limited, and a red fluorescent material can be suitably used by using various red fluorescent materials and red phosphorescent materials in combination of one or more kinds.
The red fluorescent material is not particularly limited as long as it emits red fluorescence. For example, perylene derivatives, europium complexes, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, porphyrin derivatives, Nile red, 2- (1, 1-dimethylethyl) -6- (2- (2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H-benzo (ij) quinolidin-9-yl) ethenyl)- 4H-pyran-4H-ylidene) propanedinitrile (DCJTB), 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM) and the like.

The red phosphorescent material is not particularly limited as long as it emits red phosphorescence, and examples thereof include metal complexes such as iridium, ruthenium, platinum, osmium, rhenium, and palladium. Among the ligands of these metal complexes, And those having at least one of phenylpyridine skeleton, bipyridyl skeleton, porphyrin skeleton and the like. More specifically, tris (1-phenylisoquinoline) iridium, bis [2- (2′-benzo [4,5-α] thienyl) pyridinate-N, C ³ ′] iridium (acetylacetonate) (btp2Ir ( acac)), 2,3,7,8,12,13,17,18-octaethyl-12H, 23H-porphyrin-platinum (II), bis [2- (2′-benzo [4,5-α] thienyl ) Pyridinate-N, C ³ '] iridium, bis (2-phenylpyridine) iridium (acetylacetonate).

Among the above-mentioned, the red light emitting material preferably contains a perylene derivative. A perylene derivative is a light-emitting material with particularly high luminous efficiency. The perylene derivative has a particularly excellent function of capturing electrons. For this reason, the electrons injected from the cathode 12 side can be reliably captured by the first light-emitting layer 6 and can be prevented from being injected into the hole transport layer 5. As a result, it is possible to prevent the constituent materials of the hole injection layer 4 and the hole transport layer 5 from being reduced and deteriorated by electrons.
In particular, as the perylene derivative used for the red light emitting material, for example, a tetraphenyldiindenoperylene derivative such as a compound represented by the following formula (6-1) is preferably used.

The first host material having such a red light emitting material as a guest material recombines holes and electrons to generate excitons, and transfers the exciton energy to the red light emitting material (Förster transfer). Or a Dexter movement) to excite the red light emitting material.
Such a first host material is not particularly limited as long as it exhibits the above-described function with respect to the red light emitting material to be used. When the red light emitting material includes a red fluorescent material, for example, A styrylarylene derivative, a tetracene derivative (naphthacene derivative) such as a compound represented by the following formula (6a-1), an anthracene derivative such as a compound represented by the following formula (6a-2), a distyrylbenzene derivative, a distyrylamine derivative, Quinolinolato metal complexes such as tris (8-quinolinolato) aluminum complex (Alq ₃ ), triarylamine derivatives such as tetramers of triphenylamine, oxadiazole derivatives, silole derivatives, dicarbazole derivatives, oligothiophene derivatives, benzopyrans Derivatives, triazole derivatives, benzoxazo Derivatives, benzothiazole derivatives, quinoline derivatives, 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi), etc., one of which is used alone or in combination of two or more. You can also.

Further, when the red light emitting material includes a red phosphorescent material, examples of the first host material include 3-phenyl-4- (1′-naphthyl) -5-phenylcarbazole, 4,4′-N, N ′. -Carbazole derivatives, such as dicarbazole biphenyl (CBP), etc. are mentioned, Among these, it can also be used individually by 1 type or in combination of 2 or more types.
When the red light emitting material (guest material) and the first host material as described above are used, the content (dope amount) of the red light emitting material in the first light emitting layer 6 is 0.1 to 10 wt%. Is preferable, and it is more preferable that it is 1-5 wt%. By setting the content of the red light emitting material in such a range, the light emission efficiency can be optimized, and the amount of light emitted from the second light emitting layer 8 and the third light emitting layer 9 described later is balanced. In addition, the first light emitting layer 6 can emit light.

Further, since the red light emitting material as described above has a relatively small band gap, it easily emits light. Therefore, by providing the red light emitting layer closest to the anode 3, the blue light emitting layer and the green light emitting layer, which have a relatively large band gap and are difficult to emit light, can be set to the cathode 12 side, and each light emitting layer can emit light in a balanced manner.
Moreover, the average thickness of the 1st light emitting layer 6 is although it does not specifically limit, It is preferable that it is 1-100 nm, It is more preferable that it is 3-50 nm, It is further more preferable that it is 5-30 nm.

(Middle layer)
The intermediate layer 7 is provided between and in contact with the first light-emitting layer 6 and the second light-emitting layer 8 described later. The intermediate layer 7 has a function of preventing exciton energy from moving between the first light emitting layer 6 and the second light emitting layer 8. With this function, the first light emitting layer 6 and the second light emitting layer 8 can each emit light efficiently.

The constituent material of the intermediate layer 7 is not particularly limited as long as the intermediate layer 7 can exhibit the function as described above, but an amine material or the like can be used. A mixed material of the system material and the acene material can be preferably used.
The amine-based material used for the intermediate layer 7 is not particularly limited as long as it has an amine skeleton and the intermediate layer 7 exhibits the function described above. Among the hole transport materials, materials having an amine skeleton can be used, but benzidine-based amine derivatives are preferably used.

  In particular, among the benzidine-based amine derivatives, the amine-based material used for the intermediate layer 7 is preferably one in which two or more naphthyl groups are introduced. Examples of such benzidine-based amine derivatives include N, N′-bis (1-naphthyl) -N, N′-diphenyl [1,1′-biphenyl] -4,4′-diamine (α-NPD). And N, N, N ′, N′-tetranaphthyl-benzidine (TNB) and the like.

Such amine-based materials are generally excellent in hole transport properties, and the hole mobility of amine-based materials is higher than the hole mobility of acene-based materials described later. Therefore, holes can be smoothly transferred from the first light emitting layer 6 to the second light emitting layer 8 through the intermediate layer 7.
The content of the amine-based material in the intermediate layer 7 is not particularly limited, but is preferably 10 to 90 wt%, more preferably 30 to 70 wt%, and 40 to 60 wt%. Further preferred.

  On the other hand, the acene-based material used for the intermediate layer 7 is not particularly limited as long as it has an acene skeleton and the intermediate layer 7 exhibits the functions described above. For example, a naphthalene derivative, anthracene Derivatives, tetracene derivatives, pentacene derivatives, hexacene derivatives, heptacene derivatives and the like can be mentioned, and one or more of these can be used in combination, but naphthalene derivatives and anthracene derivatives are preferably used.

The content of the acene-based material in the intermediate layer 7 is not particularly limited, but is preferably 10 to 90 wt%, more preferably 30 to 70 wt%, and 40 to 60 wt%. Further preferred.
Further, when the content of the acene-based material in the intermediate layer 7 is A [wt%] and the content of the amine-based material in the intermediate layer 7 is B [wt%], B / (A + B) is It is preferably 0.1 to 0.9, more preferably 0.3 to 0.7, and still more preferably 0.4 to 0.6. Accordingly, the first layer 6 and the second layer 8 are made to inject electrons and holes to emit light while ensuring the resistance of the intermediate layer 7 to carriers and excitons more reliably. Can do.

Moreover, although the average thickness of the intermediate | middle layer 7 is not specifically limited, It is preferable that it is 1-100 nm, It is more preferable that it is 3-50 nm, It is further more preferable that it is 5-30 nm. Accordingly, the intermediate layer 7 can more reliably prevent exciton energy transfer between the first light emitting layer 6 and the second light emitting layer 8 while suppressing the driving voltage.
On the other hand, when the average thickness of the intermediate layer 7 exceeds the upper limit value, depending on the constituent material of the intermediate layer 7, the driving voltage becomes remarkably high, or the light emission of the light emitting element 1 _R (particularly white light emission) is difficult. It may become. On the other hand, if the average thickness of the intermediate layer 7 is less than the lower limit value, the intermediate layer 7 may be formed between the first light emitting layer 6 and the second light emitting layer 8 depending on the constituent material of the intermediate layer 7, the driving voltage, and the like. It is difficult to prevent or suppress energy transfer due to excitons between them, and the resistance of the intermediate layer 7 to carriers and excitons tends to decrease.
The intermediate layer 7 can be omitted.

(Second light emitting layer)
The second light-emitting layer 8 includes a second light-emitting material that emits light in the second color and a second host material that uses the second light-emitting material as a guest material. Similar to the first light emitting layer 6 described above, the second light emitting layer 8 can be formed, for example, by doping the second host material as a dopant with the second light emitting material as a guest material. it can. Note that the second host material can be omitted.

The second light emitting material is a blue light emitting material that emits blue light.
Such a blue light-emitting material is not particularly limited, and a blue fluorescent material can be suitably used by using various blue fluorescent materials and blue phosphorescent materials in combination of one or more.
The blue fluorescent material is not particularly limited as long as it emits blue fluorescence. For example, a compound represented by the following formula (8-1), a distyryldiamine derivative, a distyryl derivative, a fluoranthene derivative, a pyrene derivative, perylene And perylene derivatives, anthracene derivatives, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, chrysene derivatives, phenanthrene derivatives, distyrylbenzene derivatives, tetraphenylbutadiene, 4,4'-bis (9-ethyl-3-carbazovinylene)- 1,1′-biphenyl (BCzVBi) and the like can be mentioned, and one of these can be used alone or in combination of two or more.

The blue phosphorescent material is not particularly limited as long as it emits blue phosphorescence, and examples thereof include metal complexes such as iridium, ruthenium, platinum, osmium, rhenium, and palladium. More specifically, bis [4,6-difluorophenyl pyridinium sulfonate -N, ^{C 2} '] - picolinate - iridium, tris [2- (2,4-difluorophenyl) pyridinate -N, ^{C 2']} iridium , bis [2- (3,5-trifluoromethyl) pyridinate -N, ^{C 2} '] - picolinate - iridium, bis (4,6-difluorophenyl pyridinium sulfonate -N, ^{C 2')} iridium (acetylacetonate ).

As the second host material, the same material as the first host material of the first light emitting layer 6 described above can be used.
When the blue light emitting material (guest material) and the second host material as described above are used, the content (dope amount) of the blue light emitting material in the second light emitting layer 8 is 0.1 to 20 wt%. Is preferable, and it is more preferable that it is 5-20 wt%. By setting the content of the blue light emitting material in such a range, the light emission efficiency can be optimized, and the balance with the light emission amount of the first light emitting layer 6 described above and the third light emitting layer 9 described later. The second light emitting layer 8 can emit light while taking
The average thickness of the second light emitting layer 8 is not particularly limited, but is preferably 1 to 100 nm, more preferably 5 to 60 nm, and further preferably 10 to 40 nm.

(Third light emitting layer)
The third light-emitting layer 9 includes a third light-emitting material that emits light in the third color and a third host material that uses the third light-emitting material as a guest material. Similar to the first light emitting layer 6 described above, the third light emitting layer 9 can be formed, for example, by doping a third host material as a dopant with a third light emitting material as a guest material. it can. Note that the third host material can be omitted.

The third light emitting material is a green light emitting material that emits green light.
Such a green light emitting material is not particularly limited, and a green fluorescent material can be suitably used by using various green fluorescent materials and green phosphorescent materials in combination of one or more kinds.
The green fluorescent material is not particularly limited as long as it emits green fluorescence. For example, a coumarin derivative, a quinacridone derivative such as a compound represented by the following formula (9-1), 9,10-bis [(9- Ethyl-3-carbazole) -vinylenyl] -anthracene and the like, and one of them may be used alone or two or more of them may be used in combination.

  The green phosphorescent material is not particularly limited as long as it emits green phosphorescence, and examples thereof include metal complexes such as iridium, ruthenium, platinum, osmium, rhenium, and palladium. Among these, at least one of the ligands of these metal complexes preferably has a phenylpyridine skeleton, a bipyridyl skeleton, a porphyrin skeleton, or the like. More specifically, fac-tris (2-phenylpyridine) iridium (Ir (ppy) 3), bis (2-phenylpyridinate-N, C2 ′) iridium (acetylacetonate), fac-tris [5 -Fluoro-2- (5-trifluoromethyl-2-pyridine) phenyl-C, N] iridium.

As the third host material, the same material as the first host material of the first light emitting layer 6 described above can be used.
When the green light emitting material (guest material) and the third host material as described above are used, the content (dope amount) of the green light emitting material in the third light emitting layer 9 is 0.1 to 20 wt%. Is preferable, and it is more preferable that it is 1-20 wt%. By setting the content of the green light emitting material within such a range, it is possible to optimize the light emission efficiency, and to balance the light emission amounts of the first light emitting layer 6 and the second light emitting layer 8 described above. In addition, the third light emitting layer 9 can emit light.
Moreover, the average thickness of the 3rd light emitting layer 9 is although it does not specifically limit, It is preferable that it is 1-100 nm, It is more preferable that it is 5-60 nm, It is further more preferable that it is 10-40 nm.

(Electron transport layer)
The electron transport layer 10 has a function of transporting electrons injected from the cathode 12 through the electron injection layer 11 to the third light emitting layer 9.
As a constituent material (electron transport material) of the electron transport layer 10, for example, an amine-based material (phenanthroline derivative) such as a compound (BPhen) represented by the following formula (10-1), or a formula (10-2) Quinoline derivatives such as organometallic complexes having 8-quinolinol and its derivatives such as tris (8-quinolinolato) aluminum (Alq ₃ ) as a ligand, oxadiazole derivatives, perylene derivatives, pyridine derivatives, pyrimidines Derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives and the like can be mentioned, and one or more of these can be used in combination.

Although the average thickness of the electron carrying layer 10 is not specifically limited, It is preferable that it is about 0.5-100 nm, and it is more preferable that it is about 1-50 nm.
In addition, when the electron transport layer 10 is formed using two or more kinds of materials, the electron transport layer 10 may be formed as one layer composed of a material obtained by mixing these materials, or a plurality of layers composed of each material. Layers may be stacked.
The electron transport layer 10 can be omitted.

(Electron injection layer)
The electron injection layer 11 has a function of improving the efficiency of electron injection from the cathode 12.
Examples of the constituent material (electron injection material) of the electron injection layer 11 include various inorganic insulating materials and various inorganic semiconductor materials.

Examples of such inorganic insulating materials include alkali metal chalcogenides (oxides, sulfides, selenides, tellurides), alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides. Of these, one or two or more of these can be used in combination. By forming the electron injection layer using these as main materials, the electron injection property can be further improved. In particular, an alkali metal compound (alkali metal chalcogenide, alkali metal halide, etc.) has a very small work function, and the light-emitting element 1 _R can obtain high luminance by forming the electron injection layer 11 using the work function. It becomes.

Examples of the alkali metal chalcogenide include Li ₂ O, LiO, Na ₂ S, Na ₂ Se, and NaO.
Examples of the alkaline earth metal chalcogenide include CaO, BaO, SrO, BeO, BaS, MgO, and CaSe.
Examples of the alkali metal halide include CsF, LiF, NaF, KF, LiCl, KCl, and NaCl.
Examples of the alkaline earth metal halide include CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ , and BeF ₂ .

In addition, as the inorganic semiconductor material, for example, an oxide including at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb, and Zn , Nitrides, oxynitrides, and the like, and one or more of these can be used in combination.
The average thickness of the electron injection layer 11 is not particularly limited, but is preferably about 0.1 to 1000 nm, more preferably about 0.2 to 100 nm, and about 0.2 to 50 nm. Further preferred.
The electron injection layer 11 can be omitted.

(cathode)
The cathode 12 is an electrode (second electrode) that injects electrons into the electron transport layer 10 via the electron injection layer 11 described above.
The cathode 12 has a function of transmitting a part of light from at least one of the first light-emitting layer 6, the second light-emitting layer 8, and the third light-emitting layer 9 and reflecting the remainder. It also has. Thereby, the light emitting element _1R can emit light from the cathode 12 side. Further, it is possible to improve the luminous efficiency of the light-emitting element 1 _R by effectively utilizing the light reflected by the cathode 12.

As a constituent material of the cathode 12, a material having a small work function is used. For example, Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, or an alloy containing these may be used, and one or more of these may be used in combination (for example, a multi-layer laminate).
In particular, when an alloy is used as the constituent material of the cathode 12, it is preferable to use an alloy containing a stable metal element such as Ag, Al, or Cu, specifically, an alloy such as MgAg, AlLi, or CuLi. By using such an alloy as a constituent material of the cathode 12, the electron injection efficiency and stability of the cathode can be made excellent.

Moreover, although the average thickness of the cathode 12 is not specifically limited, It is preferable that it is about 100-10000 nm, and it is more preferable that it is about 200-500 nm.
The reflectance of the cathode 12 with respect to light from the light-emitting layer (the desired wavelength emitted from the light emitting element _{1 R)} is preferably from 20 to 80%, and more preferably 30 to 70%. This can increase the brightness of the light emitted from the light emitting element 1 _R (current efficiency) effectively.

(Reflective film)
The reflective film (reflective layer) 42 is provided on the side opposite to the cathode 12 with respect to the first light emitting layer 6, the second light emitting layer 8, and the third light emitting layer 9 described above. That is, the first light emitting layer 6, the second light emitting layer 8, and the third light emitting layer 9 are provided between the reflective film 42 and the cathode 12.
Such a reflective film 42 has a function of reflecting light from at least one light emitting layer among the first light emitting layer 6, the second light emitting layer 8, and the third light emitting layer 9. This can increase at least one layer of the light reflected from the optical and the cathode 12 from the light-emitting layer is reflected by the reflecting film 42, the brightness of the light emitted from the light emitting element 1 _R. As a result, the light emission efficiency of the light emitting element _1R can be improved.

The constituent material of the reflective film 42 is not particularly limited as long as the reflective film 42 can exhibit the function as described above, and Al, Ni, Co, Ag, an alloy containing these, or the like Can be used.
The reflective film 42 can also be formed of a dielectric multilayer film (optical multilayer thin film) in which high refractive index layers and low refractive index layers are alternately stacked.

The material constituting the high refractive index layer, for _{example, Ti 2 O, Ta 2 O} 5, niobium _{oxide, Al 2 O 3, HfO 2} , ZrO 2, although ThO ₂ and the like, in particular, _Ti 2 O, Ta ₂ O ₅ , niobium oxide and the like are preferably used.
Examples of the material constituting the low refractive index layer include MgF ₂ and SiO ₂ , and SiO ₂ is particularly preferably used.

The number and thickness of the high refractive index layer and the low refractive index layer constituting the reflection film 42 are set according to the required optical characteristics. In general, when a reflective film is formed of a dielectric multilayer film, the number of layers required to obtain the optical characteristics is 12 or more.
In the present embodiment, since the light-emitting element 1 _R is a top emission type, light transmitting the reflective film 42 is not required.
The thickness of the reflective film 42 is not particularly limited as long as it exhibits the above-described function, but is preferably about 1 to 100 nm.

(Corrosion prevention film)
The corrosion prevention film 43 has a function of preventing the reflection film 42 from being corroded (function as a protective layer for protecting the reflection film 42).
The constituent material of the corrosion prevention film 43 is not particularly limited as long as the corrosion prevention film 43 exhibits the function described above and does not impair the function of the reflection film 42 described above. Inorganic materials can be used.
The corrosion prevention film 43 may be omitted.

(Cathode cover)
The cathode cover 44 is provided so as to cover the anode 3, the laminate 15, and the cathode 12, and has a function of hermetically sealing them and blocking oxygen and moisture. By providing the cathode cover 44, improving the reliability of the light emitting element 1 _R or, the effect of such prevention of alteration or deterioration (improvement of durability) is obtained.

Examples of the constituent material of the cathode cover 44 include Al, Au, Cr, Nb, Ta, Ti, alloys containing these, silicon oxide, various resin materials, and the like. In addition, when using the material which has electroconductivity as a constituent material of the cathode cover 44, in order to prevent a short circuit, between the cathode cover 44 and the anode 3, the laminated body 15, and the cathode 12 as needed. Thus, an insulating film is preferably provided.
In this embodiment, the resin layer 45 (sealing layer) and the color filter 102 (sealing member) shown in FIG. 1 are also provided so as to cover the anode 3, the laminate 15, and the cathode 12. Sealing, and has a function of blocking oxygen and moisture.

(Manufacturing method of display device (light emitting element))
The display device 100 (light emitting elements 1 _R , 1 _G , 1 _B ) configured as described above can be manufactured, for example, as follows. In the following description, a case where the display device 100 is manufactured will be described as an example. Hereinafter, a case where the constituent material and thickness of the hole injection layer 4 _G of the light emitting element 1 _G and the constituent material and thickness of the hole injection layer 4 _B of the light emitting element 1 _B are equal to each other will be described as an example.

3 and 4 are schematic cross-sectional views for explaining an example of a method for manufacturing the display device (light emitting element) shown in FIG. In the following description, for convenience of explanation, the upper side in FIGS. 3 and 4 is described as “upper” and the lower side is described as “lower”.
The manufacturing method of the display device 100 includes: <A> forming a base material; <B> forming the light emitting elements 1 _R , 1 _G , 1 _B on the base material to form the light emitting device 101; C> a step of bonding the light emitting device 101 and the substrate 20 via the resin layer 45.
Here, in the step <B>, in forming the light emitting elements 1 _R , 1 _G , 1 _B , a step of forming the <B1> anode 3 and a step of forming the <B2> light emitting layers 6, 8, 9. And <B3> forming a cathode 12.

Hereinafter, each process in the manufacturing method of the display apparatus 100 is demonstrated sequentially.
<A> Step of Forming Base Material [1] First, a substrate 21 is prepared, and a plurality of switching elements 24 and a planarizing layer 22 are formed on the substrate 21 as shown in FIG.
The switching element 24 and the planarizing layer 22 are formed by chemical vapor deposition (CVD) such as plasma CVD and thermal CVD, dry plating such as vacuum deposition, wet plating such as electrolytic plating, thermal spraying, sol / gel, respectively. It can be formed using a method, a MOD method, thin film bonding, or the like.

[2] Next, as shown in FIG. 3B, the reflective film 42 and the corrosion prevention film 43 are stacked in this order on the planarizing layer 22 corresponding to each switching element 24. .
The reflective film 42 and the corrosion prevention film 43 are respectively formed by chemical vapor deposition (CVD) such as plasma CVD and thermal CVD, dry plating such as vacuum deposition, wet plating such as electrolytic plating, thermal spraying, and sol-gel method. MOD method, thin film bonding, or the like.
The base material can be formed as described above.

<B> Step of Forming Light-Emitting Device <B1> Step of Forming Anode [3] Next, as shown in FIG. 3C, the anode 3 is formed on the corrosion prevention film 43 of each pixel.
The anode 3 can be formed by, for example, a vapor deposition method (vapor phase process) using a CVD method, a dry plating method such as vacuum deposition or sputtering.

<B2> Step of Forming Each Light-Emitting Layer [4] Next, as shown in FIG. 3D, the hole injection layer 4 (4 _B , 4 _G ) is formed on the anode 3 corresponding to the B and G pixels. Form.
The hole injection layers 4 _G and 4 _B can be formed by, for example, a vapor deposition method (vapor phase process) using a CVD method, a dry plating method such as vacuum deposition or sputtering, or the like.

For example, as shown in FIG. 3 (d), B, opening in a region corresponding to the G pixel _M B, the membrane process-phase gas through a mask M1 having a _{M G,} the hole injection layer ₄ G, _{4 B} Form.
In addition, the hole injection layers 4 _G and 4 _B are dried (for example, after a hole injection layer forming material obtained by dissolving a hole injection material in a solvent or dispersing in a dispersion medium is supplied onto the anode 3). It can also be formed by removing a solvent or a dispersion medium.

As a method for supplying the hole injection layer forming material, for example, various coating methods such as a spin coating method, a roll coating method, and an ink jet printing method can be used. By using such a coating method, the hole injection layers 4 _G and 4 _B can be formed relatively easily.
Examples of the solvent or dispersion medium used for the preparation of the hole injection layer forming material include various inorganic solvents, various organic solvents, or mixed solvents containing these.

The drying can be performed, for example, by standing in an atmospheric pressure or a reduced pressure atmosphere, heat treatment, or blowing an inert gas.
Prior to this step, the upper surface of the anode 3 may be subjected to oxygen plasma treatment. Thereby, it is possible to impart lyophilicity to the upper surface of the anode 3, remove (clean) organic substances adhering to the upper surface of the anode 3, adjust the work function near the upper surface of the anode 3, and the like. .
Here, the oxygen plasma treatment conditions include, for example, a plasma power of about 100 to 800 W, an oxygen gas flow rate of about 50 to 100 mL / min, a conveyance speed of the member to be treated (anode 3) of about 0.5 to 10 mm / sec, and a substrate. The temperature of 2 is preferably about 70 to 90 ° C.

[5] Next, as shown in FIG. 3E, the hole injection layer 4 (4 _R ) is formed on the anode 3 corresponding to the R pixel. At this time, the hole injection layer _4R is formed using a material different from the material used in the above-described step [4].
The hole injection layer 4 _R is formed, for example, by a vapor deposition method using a CVD method, a dry plating method such as vacuum deposition, sputtering, or the like (similar to the method for forming the hole injection layers 4 _G and 4 _B described above). (Vapor phase process).

For example, as shown in FIG. 3 (e), the via mask M2 having an opening M _R in a region corresponding to the R pixel vapor deposition to form the hole injection layer 4 _G, 4 _B.
In addition, the hole injection layer 4 _R is formed by supplying a hole injection layer forming material obtained by, for example, dissolving a hole injection material in a solvent or dispersing in a dispersion medium onto the anode 3 and then drying (desolving or removing the solvent). It can also be formed by dedispersing medium).

As a method for supplying the hole injection layer forming material, for example, various coating methods such as a spin coating method, a roll coating method, and an ink jet printing method can be used. By using such a coating method, it is possible to relatively easily form the hole injection layer 4 _R.
Examples of the solvent or dispersion medium used for the preparation of the hole injection layer forming material include various inorganic solvents, various organic solvents, or mixed solvents containing these.
The drying can be performed, for example, by standing in an atmospheric pressure or a reduced pressure atmosphere, heat treatment, or blowing an inert gas.

[6] Next, as shown in FIG. 4A, a partition wall 41 is formed between the anodes 3.
The partition wall 41 is formed by chemical vapor deposition (CVD) such as plasma CVD or thermal CVD, dry plating such as vacuum deposition, wet plating such as electrolytic plating, thermal spraying, sol-gel method, MOD method, thin film bonding, etc. Can be used.

[7] Next, as shown in FIG. 4B, the hole transport layer 5, the first light emitting layer 6, the intermediate layer 7, the second light emitting layer 8, the third light emitting layer 9, and the electron transport layer. 10, the electron injection layer 11, the cathode 12, and the cathode cover 44 are laminated in this order. That is, the layer 15 excluding the hole injection layer 4 and the cathode 12 and the cathode cover 44 of the laminate 15 are formed. Thereby, a plurality of light emitting elements 1 _R , 1 _G , 1 _B are obtained. Such a plurality of light-emitting elements 1 _R , 1 _G , 1 _B have substantially the same layer structure, and therefore require relatively few and simple manufacturing processes.

Hereinafter, this process [7] is demonstrated more concretely.
[7-1] First, a hole transport layer 5 on the hole injection layer _{4 (4 R, 4 G,} 4 B).
The hole transport layer 5 can be formed, for example, by a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering.
Further, by supplying a hole transport layer forming material obtained by dissolving a hole transport material in a solvent or dispersing in a dispersion medium onto the hole injection layer 4, drying (desolvation or dedispersion medium) is performed. Can also be formed.

[7-2] Next, the first light emitting layer 6 is formed on the hole transport layer 5.
The first light emitting layer 6 can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition, sputtering, or the like.
[7-3] Next, the intermediate layer 7 is formed on the first light emitting layer 6.
The intermediate layer 7 can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition, sputtering, or the like.

[7-4] Next, the second light emitting layer 8 is formed on the intermediate layer 7.
The second light emitting layer 8 can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, or the like.
[7-5] Next, the third light emitting layer 9 is formed on the second light emitting layer 8.
The third light emitting layer 9 can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering.

[7-6] Next, the electron transport layer 10 is formed on the third light emitting layer 9.
The electron transport layer 10 can be formed by a vapor phase process using, for example, a CVD method, a dry plating method such as vacuum deposition, sputtering, or the like.
In addition, the electron transport layer 10 is dried (desolvent or solvent-free) after supplying an electron transport layer forming material obtained by, for example, dissolving an electron transport material in a solvent or dispersing in a dispersion medium onto the third light emitting layer 9. It can also be formed by dedispersing medium).

[7-7] Next, the electron injection layer 11 is formed on the electron transport layer 10.
When an inorganic material is used as the constituent material of the electron injection layer 11, the electron injection layer 11 is formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, or coating and baking of inorganic fine particle ink. Etc. can be used.
[7-8] Next, the cathode 12 is formed on the electron injection layer 11.
The cathode 12 can be formed using, for example, a vacuum evaporation method, a sputtering method, bonding of metal foil, application and baking of metal fine particle ink, and the like.

[7-9] Next, the cathode cover 44 is formed on the cathode 12.
The cathode cover 44 is formed by chemical vapor deposition (CVD) such as plasma CVD or thermal CVD, dry plating such as vacuum deposition, wet plating such as electrolytic plating, thermal spraying, sol-gel method, MOD method, thin film bonding. Etc. can be used.
The light emitting device 101 is obtained through the steps as described above.

<C> Step of Joining Light-Emitting Device and Substrate [8] Thereafter, as shown in FIG. 4C, the light-emitting device 101 and the color filter 102 are joined via the resin layer 45. Thereby, the display apparatus 100 is obtained.
Through the steps as described above, the display device 100 is obtained.
According to such a display device 100, different degree of hole injection of the hole injection layer ₄ G, _{4 B} and the hole injection layer _{4 R} of the light-emitting element _{1 R} light emitting element ₁ G, _{1 B} to each other Thus, the light emitting characteristics of the light emitting element 16 of the light emitting element 1 _R and the light emitting elements 16 of the light emitting elements 1 _G and 1 _B are made different from each other, so that the light emitting element 1 _R and the light emitting element 1 _R Even if the layer configurations of the light emitting elements 1 _G and 1 _B are the same, the emission spectrum of the light emitting part 16 of the light emitting element 1 _R and the emission spectrum of the light emitting part 16 of the light emitting elements 1 _G and 1 _B can be made different. .

Therefore, while the light emitting element _{1 R, 1 G, 1 B} of the production shall respectively easy, the emission spectrum of the light-emitting element _{1 R, 1 G, 1 B} of the light emitting portion 16, corresponding filter unit ₁₉ to R, 19 _G , 19 _B transmission.
In addition, since each of the light emitting portions 16 of the light emitting elements 1 _R , 1 _G , and 1 _{B includes} a plurality of light emitting layers, the portions contributing to the light emission of the light emitting portion 16 (specifically, the light emitting layer and the light emitting layer and its adjacent layers) The vicinity of the interface between the two can be increased. Therefore, the load on the light emitting units 16 of the light emitting elements 1 _R , 1 _G , and 1 _B can be suppressed. As a result, it is possible to prevent or suppress the deterioration of the light emitting element _{1 R, 1 G, 1 B} , achieving the light emitting element _{1 R,} 1 long life of the G, _{1 B.}
For these reasons, it is possible to improve the light emission efficiency and the life of the display device 100 while improving the manufacturing yield of the display device 100.
The display device 100 (the display device of the present invention) as described above can be incorporated into various electronic devices. Such an electronic device has excellent reliability.

FIG. 5 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.
In this figure, a personal computer 1100 includes a main body 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display. The display unit 1106 is rotatable with respect to the main body 1104 via a hinge structure. It is supported by.
In the personal computer 1100, the display unit included in the display unit 1106 is configured by the display device 100 described above.

FIG. 6 is a perspective view showing a configuration of a mobile phone (including PHS) to which the electronic apparatus of the present invention is applied.
In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206, and a display unit.
In the cellular phone 1200, the display unit is configured by the display device 100 described above.

FIG. 7 is a perspective view showing the configuration of a digital still camera to which the electronic apparatus of the present invention is applied. In this figure, connection with an external device is also simply shown.
Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

A display unit is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD, and functions as a finder that displays an object as an electronic image.
In the digital still camera 1300, the display unit is configured by the display device 100 described above.

A circuit board 1308 is installed inside the case. The circuit board 1308 is provided with a memory that can store (store) an imaging signal.
A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side of the case 1302 (on the back side in the illustrated configuration).
When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory of the circuit board 1308.

  In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the data communication input / output terminal 1314 as necessary. Further, the imaging signal stored in the memory of the circuit board 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.

  In addition to the personal computer (mobile personal computer) of FIG. 5, the mobile phone of FIG. 6, and the digital still camera of FIG. 7, the electronic apparatus of the present invention includes, for example, a television, a video camera, a viewfinder type, Monitor direct-view video tape recorder, laptop personal computer, car navigation system, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV Monitors, electronic binoculars, POS terminals, devices equipped with touch panels (for example, cash dispensers and automatic ticket vending machines for financial institutions), medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiographs, ultrasound diagnostic devices, internal Endoscope display device), fish finder, various measuring instruments, Vessels such (e.g., gages for vehicles, aircraft, and ships), a flight simulator, various monitors, and a projection display such as a projector.

Although the display device and the electronic apparatus of the present invention have been described based on the illustrated embodiments, the present invention is not limited to these.
For example, in the above-described embodiment, each light emitting element has been described as having three light emitting layers. However, the light emitting layer may be one layer, two layers, or four layers or more. Further, the emission color of the light emitting layer is not limited to R, G, and B in the above-described embodiment. Even when there are two or more light emitting layers, white light can be emitted by appropriately setting the emission spectrum of each light emitting layer. For example, when there are two light emitting layers, white light can be emitted by combining a blue light emitting layer and a yellow light emitting layer.

Next, specific examples of the present invention will be described.
1. Production of light emitting element (light emitting device) (Example)
<1> First, a transparent glass substrate having an average thickness of 0.5 mm was prepared. Next, a reflective layer and a corrosion prevention layer were formed in this order on the substrate by sputtering.
Here, AlNd was used as the constituent material of the reflective film, and SiN was used as the constituent material of the corrosion prevention layer (protective layer). The average thickness of the reflective layer was 70 nm, and the average thickness of the corrosion prevention layer was 70 nm.

<2> Next, an anode (ITO film) was formed on each corrosion prevention layer for each pixel by a combination of film formation by sputtering and etching.
Here, the average thickness of the ITO film of each pixel was 100 nm.
And after immersing a board | substrate in order of acetone and 2-propanol and ultrasonically cleaning, the oxygen plasma process was performed.

<3> Next, on the anodes corresponding to the G and B pixels, the compound represented by the above formula (4-4) was deposited by a vacuum deposition method to form a hole injection layer having an average thickness of 50 nm.
<4> Next, on the anode corresponding to the R pixel, the compound represented by the above formula (4-1) was deposited by a vacuum deposition method to form a hole injection layer having an average thickness of 50 nm.
<5> Next, a red light emitting layer (first light emitting layer) having an average thickness of 7 nm is formed by depositing a constituent material of the red light emitting layer on each of the hole injection layers of the R, G, and B pixels by a vacuum deposition method. Formed. As a constituent material of the red light emitting layer, a compound represented by the above formula (6-1) was used as a red light emitting material (guest material), and a compound represented by the above formula (6a-1) was used as a host material. The content (dope concentration) of the light emitting material (dopant) in the red light emitting layer was set to 3.0 wt%.

<6> Next, the constituent material of the intermediate layer was vapor-deposited on the red light emitting layer by a vacuum vapor deposition method to form an intermediate layer having an average thickness of 10 nm. As a constituent material of the intermediate layer, NPD represented by the above formula (5-1) was used as an amine material.
<7> Next, on the intermediate layer, the constituent material of the blue light emitting layer was vapor-deposited by a vacuum vapor deposition method to form a blue light emitting layer (second light emitting layer) having an average thickness of 20 nm. As a constituent material of the blue light emitting layer, a compound represented by the above formula (8-1) was used as a blue light emitting material, and a compound represented by the above formula (6a-2) was used as a host material. Further, the content (dope concentration) of the blue light emitting material (dopant) in the blue light emitting layer was 3.0 wt%.

  <8> Next, the constituent material of the green light emitting layer was deposited on the blue light emitting layer by a vacuum evaporation method, thereby forming a green light emitting layer (third light emitting layer) having an average thickness of 20 nm. As a constituent material of the green light emitting layer, a compound represented by the above formula (9-1) was used as a green light emitting material (guest material), and a compound represented by the above formula (6a-2) was used as a host material. Further, the content (dope concentration) of the green light emitting material (dopant) in the green light emitting layer was 3.0 wt%.

<9> Next, on the green light-emitting layer, tris (8-quinolinolato) aluminum (Alq ₃ ) represented by the above formula (10-2) and a compound represented by the above formula (10-1) (B-Phen) ) In this order by a vacuum deposition method to form an electron transport layer having an average thickness of 25 nm. Here, the average thickness of 15 and a layer (first electron transport layer) formed of tris (8-quinolinolato) aluminum (Alq ₃ ) represented by the above formula (10-2) is 15 nm, The average thickness of the layer (first electron transporting layer) formed of the compound (B-Phen) represented by the above formula (10-1) was 10 nm.

<10> Next, LiF was formed into a film on the electron transport layer by a vacuum vapor deposition method to form a cathode having an average thickness of 1 nm.
<11> Next, a MgAg (Mg: Ag = 10: 1) film was formed on the electron injection layer by a vacuum evaporation method to form a cathode (semi-transmissive layer) having an average thickness of 10 nm.
As described above, a light emitting element for each of R, G, and B pixels was formed on the substrate. As a result, a light emitting device was obtained.

(Comparative example)
In all of the light emitting elements of R, G, and B pixels, the compound represented by the above formula (4-4) is used as the constituent material of the hole injection layer, and the average thickness of the hole injection layer is 40 nm. As described above, except that a hole transport layer having an average thickness of 10 nm was formed between the hole injection layer and the first light emitting layer using the compound (α-NPD) represented by the above formula (5-1). A light emitting device (light emitting device) was manufactured in the same manner as in the example.

2. Evaluation Regarding the light emitting devices of Examples and Comparative Examples, each of the R, G, and B filters in combination with a color filter that includes R, G, and B filter units corresponding to the R, G, and B pixels, respectively. The brightness of the light transmitted through the part was measured.
The results are shown in Table 1. In Table 1, the “efficiency improvement degree” indicates the evaluation result of the luminance with the luminance evaluation result of the comparative example as a reference (1).

In addition, FIG. 8 shows an emission spectrum of each pixel in the light emitting devices of the example and the comparative example in a state where the color filter is not combined.
As is clear from Table 1, the efficiency of the light emitting device (display device) of the example is improved as compared with the light emitting device (display device) of the comparative example.
Further, as shown in FIG. 8, in the light emitting device of the example, the light emitting elements of the R pixels have an emission spectrum suitable for the R filter unit, and the light emitting elements of the G and B pixels are used in the G and B filter units. It has a suitable emission spectrum.

DESCRIPTION OF SYMBOLS 1, 1 _B , 1 _G , 1 _R ... Light emitting element 3 ... Anode 4, 4 _B , 4 _G , 4 _R ... Hole injection layer 5 ... Hole transport layer 6 ... Red light emitting layer 7 ... Intermediate layer 8 ... Blue light emitting layer 9 ... Green light emitting layer 10 ... Electron transport layer 11 ... Electron injection layer 12 ... Cathode 15, 15 _B , 15 _G , 15 _R ... Laminate 16 ... Light emitting part 19 _B , 19 _G , 19 _R ... Filter part 20... Sealing substrate 21... Substrate 22 ... Planarization layer 24... Switching element 241 ... Semiconductor layer 242 ... Gate insulating layer 243 ... Gate electrode 244 ... ... Source electrode 245 ... Drain electrode 27 ... Wiring 41 ... Partition 42 ... Reflective film 43 ... Corrosion prevention film 44 ... Cathode cover 45 ... Resin layer 36 ... Shading layer 100 ... Display device 100 _B , 100 _G, 100 _R ...... subpixel 101 Light emitting device 102 ... Color filter 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main body 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation buttons 1204 ... Earpiece 1206 ... Mouthpiece 1300 ... ... Digital still camera 1302 ... Case (body) 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Circuit board 1312 ... Video signal output terminal 1314 ... I / O terminal for data communication 1430 ... TV monitor 1440 ... ... personal computer M1, M2 ...... mask _{M B, M G, M R} ...... opening _{W B, W G, W R} ...... light

Claims (17)

A first light emitting element and a second light emitting element provided on one surface side of the substrate;
A first filter portion that transmits light of a first color out of light from the first light emitting element, and a second color different from the first color among light from the second light emitting element. A color filter including a second filter unit that transmits the light of
The first light emitting element and the second light emitting element are respectively
A cathode,
The anode,
A light emitting section provided between the cathode and the anode, and comprising a plurality of light emitting layers that emit light in different colors by energization between the two electrodes;
A hole injection layer provided between the anode and the light emitting portion so as to be in contact with the anode and having a hole injection property;
The hole injecting layers of the first light emitting element and the hole injecting layer of the second light emitting element have different degrees of hole injecting property, whereby the light emitting portion of the first light emitting element and the A display device characterized in that light emission characteristics of a light emitting portion of a second light emitting element are different from each other.   The display device according to claim 1, wherein the hole injection layer of the first light emitting element is made of a material different from that of the hole injection layer of the second light emitting element.   The hole mobility of the material constituting the hole injection layer of the first light emitting element is smaller than the hole mobility of the material constituting the hole injection layer of the second light emitting element. Display device. The difference between the hole mobility of the material constituting the hole injection layer of the first light emitting element and the hole mobility of the material constituting the hole injection layer of the second light emitting element is 10 ² cm. The display device according to claim 3, which is ² / Vs or more.   5. The display device according to claim 2, wherein a hole injection layer of at least one of the first light-emitting element and the second light-emitting element includes a benzidine derivative.   The display device according to claim 5, wherein the benzidine derivative is a material having an N, N, N ′, N′-tetraarylbenzidine skeleton.   The display device according to claim 2, wherein the hole injection layer of the second light emitting element includes an ionic material.   The display device according to claim 7, wherein the ionic material is PEDOT / PSS.   The display device according to claim 1, wherein an average thickness of the hole injection layer of the first light emitting element is equal to an average thickness of the hole injection layer of the second light emitting element.   The display device according to claim 1, wherein an average thickness of the hole injection layer of the first light emitting element is different from an average thickness of the hole injection layer of the second light emitting element.   The display device according to claim 1, wherein each of the first light emitting element and the second light emitting element has a top emission structure.   The display device according to claim 1, wherein the first light-emitting element and the second light-emitting element are made of the same material that constitutes each layer other than the hole injection layer. A third light emitting element disposed on one side of the substrate;
The color filter includes a third filter unit that converts light from the third light emitting element into a third color different from the first color and the second color,
The third light emitting element is:
A cathode,
The anode,
A light-emitting unit that is provided between the cathode and the anode and includes a plurality of light-emitting layers that emit light when energized therebetween;
A hole injection layer provided between the anode and the light-emitting portion so as to be in contact with the anode and configured to include a hole injection material;
The hole injecting material contained in the hole injecting layer of the third light emitting element is different from the hole injecting material contained in the hole injecting layer of the first light emitting element. The display device described in 1.   The display device according to claim 13, wherein a material constituting the hole injection layer of the third light emitting element is the same as a material constituting the hole injection layer of the second light emitting element.   The display device according to claim 13, wherein a material constituting the hole injection layer of the third light emitting element is different from a material constituting the hole injection layer of the second light emitting element. The first color is red, the second color is blue, and the third color is green;
Each of the light emitting portions of the first light emitting element, the second light emitting element, and the third light emitting element has a red light emitting layer, a blue light emitting layer, and a green light emitting layer stacked in this order from the anode side to the cathode side. The display device according to any one of claims 12 to 15.   An electronic apparatus comprising the display device according to claim 1.

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