JP5256909B2 - Light emitting device - Google Patents

Description

The present invention relates to a light emitting device using an organic electroluminescence element as a light emitting element.

In recent years, as a light emitting device used for a display screen of a mobile phone or a personal computer, an organic electroluminescence (LED) as a light emitting element on a display surface which is a light emitting side surface (
Hereinafter, it is referred to as “organic EL”. An organic EL device that forms an image by regularly arranging elements has been considered.
Each light emitting element includes a functional layer including at least a light emitting layer (organic EL layer) between an anode and a cathode formed so as to face each other, and a current flows between the anode and the cathode. I get luminescence. The organic EL device emits such light emission from the display surface to form an image. In general, the light emission is effectively used by disposing a reflective layer on the opposite side of the display surface and reflecting the light in the direction of the display surface. In the above configuration, the display surface side electrode is formed of a transflective material, and a resonance structure is formed between the reflective layer and the light in the target wavelength range is emphasized and emitted. There are many additions.

In the organic EL device having such a configuration, reflection of external light becomes a problem. Since the reflection layer reflects not only light emission but also external light incident from the display surface, the external light reflected by the light emission is mixed in a bright place, and the contrast can be lowered.
As a means for reducing such reflection of external light, a configuration in which a circularly polarizing plate is attached to the display surface side has been proposed (see Patent Document 1). The light modulated by the circularly polarized light utilizes the property that the rotation direction is reversed by reflection, thereby suppressing the reflected light from being emitted from the display surface and improving the contrast.
Further, when the organic EL device is a color image display device, a configuration using a color filter has been proposed. Each of the three types of light-emitting elements, a red light-emitting element that emits red light, a green light-emitting element that emits green light, and a blue light-emitting element that emits blue light, transmits light in the wavelength range that emits light. By disposing a color filter that absorbs light in the wavelength range, reflection of outside light outside the wavelength range of light emission can be reduced.

Japanese Patent Laid-Open No. 9-127858

However, the above methods have the following problems. First, in the method using a circularly polarizing plate, since one polarization component of light emission is absorbed, the ratio of the light emitted from the display surface becomes less than half and the luminance is lowered. Increasing the amount of current flowing through the light emitting layer to compensate for the decrease in luminance can lead to an increase in power consumption and a decrease in the lifetime of the light emitting layer.
Further, in the method using a color filter, external light in the wavelength range emitted by each light emitting element cannot be absorbed, and thus external light reflection cannot be sufficiently reduced.
Furthermore, since any of the above methods provides the same reflection reducing means to all the three types of light emitting elements, it is not possible to consider visual sensitivity (spectral luminous efficacy), and depending on the type of light emitting element, external light There is a problem that the reduction of reflection may be insufficient.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 A light-emitting device including a plurality of types of light-emitting elements including at least a red light-emitting element that emits red light, a green light-emitting element that emits green light, and a blue light-emitting element that emits blue light, Each of the plurality of types of light emitting elements includes a first electrode, a second electrode having transflective or transmissive properties disposed on the light emitting side, and a gap between the first electrode and the second electrode. The light emitting layer, which functions as the first electrode, or is formed separately from the first electrode at a position facing the functional layer across the first electrode, with the functional layer including at least the light emitting layer sandwiched A light reflecting layer that reflects the light generated in step 2 to the second electrode side, and a light in a wavelength region other than the wavelength region of the emitted light, disposed at a position facing the reflective layer across the functional layer. A plurality of types of color filters At least one of the light emitting elements includes a semi-reflective layer disposed between the reflective layer and the functional layer, a transparent layer disposed between the reflective layer and the semi-reflective layer, And a light emitting device.

According to such a configuration, in addition to the effect of reducing external light reflection by the color filter, an effect of reducing external light reflection by the laminate of the transparent layer and the semi-reflective layer can be obtained. Therefore, the contrast of the light emitting device can be improved.

Application Example 2 In the above light emitting device, the plurality of types of light emitting elements are three types of light emitting elements, the red light emitting element, the green light emitting element, and the blue light emitting element. .

According to such a configuration, a laminate of the transparent layer and the semi-reflective layer is formed on a light-emitting element selected from the above three types of light-emitting elements and having particularly high external light reflection, thereby reflecting the external light. Can be reduced.

Application Example 3 The light-emitting device described above, wherein only the green light-emitting element includes the semi-reflective layer.

The green light emitting element tends to have a high reflectance of external light. Therefore, according to such a configuration,
Only the green light emitting element can reduce the reflection of external light, and the balance between power consumption and contrast of the light emitting device can be improved.

Application Example 4 The light emitting device described above, wherein two types of light emitting elements, the green light emitting element and the blue light emitting element, include the semi-reflective layer.

The blue light emitting element tends to have a high reflectance of external light next to the green light emitting element. Therefore, according to such a configuration, reflection of external light can be further reduced, and the balance between power consumption and contrast of the light-emitting device can be further improved.

Application Example 5 The light-emitting device described above, wherein the light-emitting layer is an organic electroluminescence layer.

Since organic electroluminescent materials have excellent luminous efficiency,
A light-emitting device with low power consumption and improved display quality can be obtained.

Application Example 6 The light-emitting device described above, wherein the semi-reflective layer is made of titanium.

The film layer made of titanium can be configured with a suitable ratio of reflectivity and transparency.
Therefore, with such a configuration, it is possible to further reduce the reflection of external light and to obtain a light-emitting device with further improved contrast.

Application Example 7 In the above light-emitting device, the semi-reflective layer is made of chromium, tantalum, or molybdenum.

A film layer made of such a material can be configured with a suitable ratio of reflectivity and transparency.
Therefore, with such a configuration, it is possible to further reduce the reflection of external light and to obtain a light-emitting device with further improved contrast.

Application Example 8 The light-emitting device described above, wherein the first electrode is an anode and the second electrode is a cathode.

According to such a configuration, it is possible to improve the extraction efficiency of light generated in the light emitting layer. Therefore, power consumption of the light emitting device can be reduced and display quality can be improved.

Application Example 9 In the above light emitting device, the anode is made of a transparent conductive material, and the transparent layer and the semi-reflective layer are formed between the reflective layer and the first electrode. A light emitting device characterized by the above.

According to such a configuration, since the layer thickness of the transparent layer and the anode can be set to suitable values, the display quality of the light emitting device can be further improved.

Application Example 10 In the above light emitting device, the transparent layer is made of a conductive material and also serves as the first electrode.

According to such a configuration, by forming the semi-reflective layer on the functional layer side of the first electrode, a laminate of the transparent layer and the semi-reflective layer can be formed. The display quality of the light emitting device can be improved while being suppressed.

Application Example 11 In the above light emitting device, the transparent layer is disposed on the functional layer side of the transparent insulating material layer, and the transparent insulating material layer disposed on the functional layer side of the reflective layer. And a transparent conductive material layer also serving as the first electrode.

According to such a configuration, since the transparent insulating material layer can function as a protective film for the reflective layer, the display quality of the light emitting device and the reliability can be improved.

Application Example 12 The light-emitting device described above, wherein the second electrode is an anode and the first electrode is a cathode.

With such a configuration, the cathode can also function as the reflective layer. Therefore, the display quality of the light emitting device can be improved while suppressing an increase in manufacturing cost.

Hereinafter, an embodiment of the present invention will be described with respect to an organic EL device as a light emitting device that displays an image by regularly arranging light emitting elements in a display region. In the drawings shown below, the dimensions and ratios of the components are appropriately different from the actual ones in order to make the components large enough to be recognized on the drawings.

(First embodiment)
(Organic EL device)
FIG. 1 shows an organic EL device according to the present embodiment and an organic EL according to each embodiment described later.
It is a circuit block diagram which shows the whole structure of an organic electroluminescent apparatus common to an apparatus. An active matrix organic EL device that forms an image in the display region 100 by individually controlling the light emission of the regularly arranged light emitting elements is taken as an example. In the display region 100, a plurality of scanning lines 102, a plurality of signal lines 104 orthogonal to the scanning lines 102, and a plurality of power supply lines 106 extending in parallel with the signal lines 104 are formed. A square section surrounded by the three types of wirings is a pixel region.

In each pixel region, a switching TFT 108 to which a scanning signal is supplied to the gate electrode via the scanning line 102, a holding capacitor 110 for holding a pixel signal supplied from the signal line 104 via the switching TFT 108, A driving TFT 112 to which a pixel signal held by the holding capacitor 110 is supplied to the gate electrode and a light emitting element 20 into which a driving current flows from the power supply line 106 via the driving TFT 112 are formed. There are three types of light emitting elements 20: a blue light emitting element 20B that emits blue light, a green light emitting element 20G that emits green light, and a red light emitting element 20R that emits red light. As will be described later, the light emitting element 20 is formed over the entire range of the anode 56 (see FIG. 2) as the first electrode and the display region 100, and the cathode 55 (see FIG. 2) having the entire range as a common potential. 2), the functional layer including the light emitting layer is sandwiched, and the driving current is supplied to the anode 56.
In the present specification, when the alphabet (R, G, B) indicating the color of the emitted light is omitted, it represents a general term for the three types of components corresponding to the three colors. For example, “light emitting element 20” is a general term for the above-described three types of light emitting elements.

Around the display area 100, a scanning line driving circuit 120 and a signal line driving circuit 130 are formed. Scanning signals are sequentially supplied from the scanning line driving circuit 120 to the scanning lines 102 in accordance with various signals supplied from an external circuit (not shown). An image signal is supplied from the signal line driver circuit 130 to the signal line 104, and a pixel driving current is supplied to the power supply line 106 from an external circuit (not shown). Note that the scan line driver circuit 120 operates and the signal line driver circuit 130.
These operations are synchronized with each other by a synchronization signal supplied from an external circuit via the synchronization signal line 140.

When the scanning line 102 is driven and the switching TFT 108 is turned on, the potential of the signal line 104 at that time is held in the holding capacitor 110, and the level of the driving TFT 112 is determined according to the state of the holding capacitor 110. Then, the power supply line 106 is connected via the driving TFT 112.
Then, a driving current flows from the anode 56 to the anode 56, and further, a driving current flows to the cathode 55 via the functional layer including the above-described light emitting layer (hereinafter referred to as “light emitting functional layer”). As a result, the light emitting layer emits light according to the magnitude of the drive current. In the display area 100, the above-described three types of light emitting elements 20 are regularly arranged. Each of the light emitting elements 20 is independently controlled to emit light according to the magnitude of the drive current, whereby a color image is formed in the display region 100.
Note that the order of arrangement of the three types of light emitting elements 20 is not limited to the order of B, G, and R, and can be arranged in the order of R, B, and G, for example. Further, the shapes of the three types of light emitting elements 20 in plan view are not limited to the same.

FIG. 2 is a diagram schematically showing a cross section of the organic EL device according to the present embodiment. The organic EL device according to this embodiment is a top emission type organic E that emits light to the counter substrate 11 side.
L device. FIG. 2 shows a total of three types of light emitting elements 2, a blue light emitting element 20 </ b> B, a green light emitting element 20 </ b> G, and a red light emitting element 20 </ b> R, regularly arranged on the surface of the element substrate 10 on the counter substrate 11 side.
0 is shown together with a driving TFT 112 for driving each light emitting element 20. The switching TFT 108 (see FIG. 1) and the like are not shown.

The element substrate 10 is bonded to the counter substrate 11 made of a translucent material through an adhesive layer 12. A color filter layer 29 is formed on one surface of the counter substrate 11, and the counter substrate is bonded so that the color filter layer faces the element substrate 10. The color filter layer 29 is composed of a total of three types of color filters 30, a red color filter 30 </ b> R, a green color filter 30 </ b> G, and a blue color filter 30 </ b> B arranged regularly, and a black matrix 35 that partitions each color filter 30. Become. And blue light emitting element 2
The blue color filter 30B is used for 0B, and the green color filter 30 is used for the green light emitting element 20G.
G and a red color filter 30R are bonded to the red light emitting element 20R so as to face each other. Each color filter 30 has a function of improving the color purity of light emitted from each light emitting element 20 and also a function of reducing reflection of external light. This function will be described later.

The light emitting element 20 is a light emitting functional layer (specifically, a light emitting layer included in the light emitting functional layer) 4.
In a region where 0 emits light when energized, that is, a region surrounded by a partition wall 77 which will be described later, each layer sandwiched between the anode 56 and the cathode 55 and the pair of electrodes, and a reflective layer 58 and a semi-reflective layer 82 which will be described later are transparent. This is a concept including an interference structure 83 including the layer 81.

On the surface of the element substrate 10 on the counter substrate 11 side, a channel region 60 made of a polysilicon (polycrystalline silicon) layer, a gate insulating film 71 made of silicon oxynitride, and a gate electrode made of polysilicon, Al (aluminum), or the like. 62 is formed. A first interlayer insulating layer 72 made of silicon oxynitride or the like is formed on the counter substrate 11 side of the TFT 112 so as to cover the driving TFT. A part of the region overlapping the channel region 60 of the first interlayer insulating layer 72 in plan view is selectively removed to form a contact hole, and a drain electrode that is electrically connected to the channel region 60 so as to fill the contact hole 64 and a source electrode 66 are formed.

A second interlayer insulating layer 73 made of silicon oxynitride or the like is formed on the opposite substrate 11 side of the drain electrode 64 and the source electrode 66. A part of the region overlapping the drain electrode 64 of the second interlayer insulating layer in a plan view is selectively removed to form a contact hole.

On the counter substrate 11 side of the second interlayer insulating layer 73, an anode 56 as a first electrode is formed via a reflective layer 58, a transparent layer 81 described later, and the like. The anode 56 is a transparent conductive material IT
It is formed by patterning a thin film of O (indium / tin oxide), and is electrically connected to the drain electrode 64 through the contact hole. Therefore, the anode 56 is electrically connected to the driving TFT 112, and the driving current supplied from the power supply line 106 can be supplied to the light emitting functional layer 40 described later. The layer thickness of the anode 56 is approximately 124 nm for the blue light emitting element 20B, approximately 22 nm for the green light emitting element 20G, and approximately 92 nm for the red light emitting element 20R.

As a material for forming the anode 56, a known transparent conductive material such as indium zinc oxide can be used in addition to the above-mentioned ITO. Further, the layer thickness of the anode 56 is not limited to the above-mentioned value, and is preferably set to a value suitable for adjusting the optical path length (resonance length) of a resonance structure 88 (see FIG. 3) described later. . The formation material and the layer thickness of the reflective layer 58 are common among the light emitting elements, and are Al having a layer thickness of approximately 100 nm.

On the counter substrate 11 side of the second interlayer insulating layer 73 and the anode 56, a partition wall 77 is formed by patterning an organic or inorganic insulating material layer such as polyimide. The patterning is performed so that a region overlapping the reflective layer 58 of the anode 56 is exposed. The light emitting functional layers 40 corresponding to the respective light emitting elements 20 are formed in the region on the counter substrate 11 side of the anode 56. Specifically, a blue light emitting functional layer 40B is formed in the region of the blue light emitting element 20B, a green light emitting functional layer 40G is formed in the region of the green light emitting element 20G, and the red light emitting element 20R.
A red light emitting functional layer 40R is formed in the above region. A material for forming each light emitting functional layer 40 will be described later.

An electron injection layer 54, a cathode 55 as a second electrode, and a sealing layer 59 are formed in the order described on the counter substrate 11 side of each of the light emitting functional layers 40 and the partition walls 77. Electron injection layer 54
Is made of LiF (lithium fluoride) having a layer thickness of about 1 nm, and is a layer that enhances the electron injection efficiency from the cathode 55 and improves the light emission efficiency. The material for forming the cathode 55 has a work function of 4.2 eV.
The following metals, or alkali metals or alkaline earth metals having a work function of 3.5 eV or less are preferable. In this embodiment, MgAg (magnesium / silver alloy) is used. The cathode 55 has a layer thickness of about 10 nm, and has a transflective property, that is, a property of reflecting about 50% of irradiated light and transmitting about 50%. The material for forming the sealing layer 59 is preferably a transparent material having a high gas barrier property. The sealing layer 59 of the organic EL device according to this embodiment has a layer thickness of about 2
It is made of 00 nm silicon nitride oxide (SiOxNy).

Each of the layers is formed so as to cover at least the entire surface of the display region 100 (see FIG. 1). The cathode 55 is grounded in an area outside the display area 100. The element substrate 10 on which the layers up to the sealing layer 59 are formed and the counter substrate 11 on which the color filter layer 29 is formed are bonded together via the adhesive layer 12 so that the sealing layer and the color filter face each other. Organic EL
It becomes a device. In addition, although the electron injection layer 54 may be referred to as the light emitting functional layer 40, the electron injection layer 54 and the light emitting functional layer 40 are described as separate layers in this specification.

As described above, the reflective layer 58 is formed on the surface of the second interlayer insulating layer 73 on the side of the counter substrate 11 that overlaps the light emitting functional layer 40 of each light emitting element 20 in plan view. Further, as described above, the anode 56 is formed of a transparent conductive material. Therefore, the light emitted from the light emitting functional layer 40 toward the element substrate 10 is transmitted through the anode 56 to reach the reflection layer 58 and then reflected to the counter substrate 11 side. Further, since the cathode 55 is formed of a transflective material, approximately 50 of the light traveling toward the counter substrate 11 out of the light generated in the light emitting functional layer 40.
% Is reflected by the cathode 55 toward the element substrate 10 side. Therefore, the cathode 55 and the reflective layer 58
A resonance structure 88 (see FIG. 3) is formed between the two.

In addition, a transparent layer 81 and a semi-reflective layer 82 are formed in the order of description on the counter substrate 11 side of the reflective layer 58 of the blue light emitting element 20B and the green light emitting element 20G.
3 is formed. The two layers are formed of a transparent layer 81 of SiN (silicon nitride) having a thickness of about 85 nm and a semi-reflective layer 82 of titanium having a thickness of about 20 nm. Red light emitting element 2
Only the transparent layer 81 is formed on the counter substrate 11 side of the 0R reflective layer 58, and the interference structure 83 is formed.
Is not formed. The organic EL device according to this embodiment includes an interference structure 83 and a resonance structure 88.
In addition, the function of the color filter 30 reduces external light reflection. Such an embodiment will be described below with reference to FIGS.

FIG. 3 is a cross-sectional view schematically showing the green light emitting element 20G, that is, each layer between the cathode 55, the anode 56, and the pair of electrodes together with the green color filter 30G and the interference structure 83 described above. Each layer which comprises the green light emission functional layer 40G of the green light emitting element 20G shown in FIG. 2 is shown in figure, and the code | symbol of the display surface 75 is added.

The display surface 75 is the surface of the green light emitting element 20G, and the display light, that is, the green light emitting functional layer 40.
It is a surface on which light emitted in G is emitted toward the observer through the green color filter 30G. The counter substrate 11 is not shown, and the interface between the green color filter 30G and the element substrate 10 is schematically used as a display surface 75.

The green light emitting functional layer 40 </ b> G includes a total of four layers including a hole injection layer 51, a hole transport layer 52, a green light emitting layer 44, and an electron transport layer 53 formed in the order described on the counter substrate 11 side of the anode 56. The layer thickness of the green light emitting functional layer 40G, that is, the total layer thickness of the four layers described above is approximately 94 nm.

The hole injection layer 51 is a layer that increases the hole injection efficiency from the anode 56 and improves the light emission efficiency. The hole transport layer 52 and the electron transport layer 53 are layers that improve the light emission efficiency by improving the hole transport property and the electron transport property to the green light emitting layer 44, respectively. As the material for forming each layer, the hole injection layer 51 is HI406 (made by Idemitsu Kosan Co., Ltd.), the hole transport layer 52 is HT320 (made by Idemitsu Kosan Co., Ltd.), and the electron transport layer 53 is Alq3 (aluminum quinolinol). .
The light emitting layer (green light emitting layer 44 or the like) is formed by mixing a host material that ensures conductivity with a dopant that has a function of emitting light by the combination of electrons and holes. The green light emitting layer 44 is
BH215 (made by Idemitsu Kosan Co., Ltd.) as a host material is mixed with quinacridone as a dopant.

In the organic EL device according to the present embodiment and the organic EL devices according to the embodiments and comparative examples described later, the blue light emitting functional layer 40B and the red light emitting element 20 of the blue light emitting element 20B are used.
Both the red light emitting functional layers 40R of R have a thickness of about 94 nm, which is the same as the thickness of the green light emitting functional layer 40G, and the forming materials are the same except for the dopant of the light emitting layer. The light emitting functional layer 4
The forming material of 0 is not limited to the above. It can be formed using a known material that contributes to light emission of a low molecular weight type and a high molecular weight type.

As described above, the organic EL device according to the present embodiment suppresses an increase in power consumption and reflects the external light reflectance, that is, the external light incident on the display surface 75, reflected by the reflective layer 58 and displayed on the display surface 7.
The objective is to reduce the ratio of the light emitted from 5 as much as possible. For this purpose, the color filter 30 is used while causing light emission of one of the three primary colors using a different dopant for each light emitting element 20, and interference is further caused on the reflective layer 58 of the blue light emitting element 20B and the green light emitting element 20G. A structure 83 is formed.

The outside light 90 is white light and includes light in a wide wavelength range. The green color filter 30G transmits light having a wavelength range of a predetermined width centered at approximately 540 nm (that is, a green light component) out of the incident light, and light other than light having a wavelength range of the predetermined width. It has a function of absorbing (non-green light component). Therefore, of the light included in the external light 90 incident on the display surface 75, the green light component (hereinafter referred to as “second external light component 92”) is the green color filter 30.
The non-green light component (hereinafter referred to as “first external light component 91”) that passes through G is absorbed by the green color filter 30G and dissipated as heat. As a result, the light (light quantity) incident on the green light emitting element 20G is greatly reduced by the green color filter 30G.

The second external light component 92 incident on the green light emitting element 20G passes through the green light emitting functional layer 40G and reaches the interference structure 83 composed of the transparent layer 81 and the semi-reflective layer 82. Here, the cathode 55
Has a transflective property, so that some of the second external light component 92 is reflected to display the display surface 7.
Although the light is emitted from 5, the description of the light is omitted.

Each layer included from the interface between the cathode 55 and the electron injection layer 54 to the interface between the anode 56 and the semi-reflective layer 82 is a layer having translucency. Therefore, the second external light component 92 reaches the interface between the anode 56 and the semi-reflective layer 82 with almost no attenuation. Then, approximately 50% is reflected at the interface between the anode 56 and the semi-reflective layer 82 to become the first reflected light 94, and the remaining approximately 50% transmitted through the interface passes through the interference structure 83 and then the surface of the reflective layer 58. The second reflected light 95 is reflected. The combined light of the first reflected light 94 and the second reflected light 95 is emitted from the display surface 75 as reflected light 93. Here, the sum of the optical distance (the product of the layer thickness and the refractive index) of the transparent layer 81 and the optical distance of the semi-reflective layer 82 is approximately a quarter of the wavelength of the second external light component 92. Is set to Therefore, the phases of the second reflected light 95 and the first reflected light 94 are shifted from each other by a half wavelength, that is, by 180 degrees. Therefore, the first reflected light 94 and the second reflected light 95 cancel each other, and the light amount of the reflected light 93 is extremely reduced compared to the light amount of the second external light component 92.

Next, light emission generated in the light emitting functional layer 40 will be described. Approximately 50% of the light generated in the green light emitting layer 44 included in the green light emitting functional layer 40G is directed to the counter substrate 11 side, and the remaining approximately 50%.
Is directed to the element substrate 10 side (the reflective layer 58 side in this figure). Hereinafter, the light traveling toward the counter substrate 11 is referred to as first light emission 86. The light reflected in the direction toward the counter substrate 11 by the reflective layer 58 facing the element substrate 10 is referred to as second light emission 87. The combined light of the first light emission 86 and the second light emission 87 is emitted light (display light) 85. The outgoing light 85 is transmitted through the green color filter 30G so that the wavelength range is narrowed and the color purity is improved.
5 is emitted.

Here, since the second light emission 87 is transmitted through the interference structure 83, the component reflected at the interface between the anode 56 and the semi-reflective layer 82 and the component transmitted through the interface cancel each other, and have a slight intensity (light quantity). descend. However, the first light emission 86 is emitted without passing through the interference structure 83. Therefore, the output light 85 as a whole is not greatly affected by the interference structure 83, and the intensity (light quantity).
The decline is limited.

The interference structure 83 may be formed between the cathode 55 and the reflective layer 58, and the light emitting functional layer 40.
And the cathode 55 can also be formed. However, when it is formed at such a position, the influence on the emitted light (display light) 85 is increased. The organic EL device of the present embodiment has an interference structure 83,
By forming the second external light component 92 at a position where only 50% of the emitted light 85 is irradiated, that is, between the reflective layer 58 and the light emitting functional layer 40, a decrease in extraction efficiency is suppressed. While reducing external light reflection.

The layer thickness of the transparent layer 81 and the layer thickness of the semi-reflective layer 82 are not fixed to the above values. Since the external light reflectance largely changes depending on the setting of the layer thickness described above, the light having the peak wavelength is matched with the peak wavelength of the external light transmitted from the color filter layer 29 to the anode 56 of each light emitting element 20. It is preferable to set so that the reflectance can be reduced. The layer thickness of the transparent layer 81 is preferably set between approximately 50 nm and 200 nm. The layer thickness of the semi-reflective layer 82 is preferably set between approximately 5 nm and 30 nm in consideration of a change in transmittance.

Next, the resonance structure 88 will be described. Since the cathode 55 is made of a transflective material, approximately 50% of the light emitted from the green light emitting layer 44 is reflected by the cathode 55 toward the reflecting layer 58. Therefore, a resonant structure 88 is formed between the cathode 55 and the reflective layer 58. When the resonance length of the resonance structure 88 (optical distance between the cathode 55 and the reflective layer 58) is an appropriate value, the above light emission causes multiple interference in the resonance structure 88, and the color purity is improved. Display surface 7
5 is emitted. Such an improvement in color purity supplements the function of the green color filter 30G, leading to an improvement in extraction efficiency. As a result, it is possible to reduce power consumption when the luminance is the same.

In order to maximize the effect of improving the color purity due to multiple interference, the optical distance L needs to satisfy the formula (1).
mλ ₁ = 2L + (φ ₂ + φ ₁ ) (1)
On the other hand, the resonance structure 88 can also fulfill the function of reducing external light reflection by canceling out the second external light component (green light component) 92 by interference. In order to maximize the effect of reducing external light reflection due to interference, the optical distance L needs to satisfy Expression (2).
(M + 1/2) λ ₂ = 2L + (φ ′ ₂ −φ ′ ₁ ) (2)
here,
m is an integer greater than or equal to 1,
L is an optical distance between the interface between the cathode 55 and the electron injection layer 54 and the interface between the reflective layer 58 and the transparent layer 81;
λ ₁ is the peak wavelength of light desired to be emitted from the display surface 75,
λ ₂ is the peak wavelength of the light whose reflection is to be reduced,
φ ₁ is a phase change of light of wavelength λ ₁ when reflected by the reflective layer 58,
φ ₂ is the phase change of the light of wavelength λ ₁ when reflected by the cathode 55,
φ ′ ₁ is a phase change of light of wavelength λ ₂ when reflected by the reflective layer 58,
φ ′ ₂ is a phase change of light of wavelength λ ₂ when reflected by the cathode 55.

The peak wavelength of light that the green light emitting element 20G wants to emit from the display surface 75 is naturally the peak wavelength of green light. Further, the external light 90 passes through the green color filter 30G, so that the second
Therefore, the peak wavelength of the light whose reflection is to be reduced by the resonance structure 88 is the peak wavelength of the green light. Therefore, λ ₁ and λ ₂ are substantially the same value. Further, the phase change of light due to reflection cannot take a very large value. Therefore, the formula (1
) And formula (2) satisfying both of them is difficult to set.

The organic EL device according to the present embodiment sets the resonance length and the like so as to satisfy such conflicting requests as much as possible, and improves color purity while reducing external light reflection, and displays the same luminance. Power consumption is reduced. As described above, the organic EL device of the present embodiment does not use a polarizing plate or the like, and the color filter hardly absorbs light in the wavelength range to be emitted, so that the extraction efficiency has a margin. Therefore, the resonance length of the resonance structure 88 can be set with an emphasis on the reduction of external light reflection while considering the improvement of color purity.

The blue light emitting element 20B transmits light (that is, a blue light component) having a wavelength range of a predetermined width centered at approximately 440 nm out of light (external light) incident on the display surface 75 by the color filter. Blue color filter 3 that absorbs light (non-blue light component) other than light in the wavelength range of
BD05 as the dopant of the light emitting layer included in the blue light emitting functional layer 40B.
Except for two points of using 2 (made by Idemitsu Kosan Co., Ltd.), it is the same structure as the green light emitting element 20G.

Next, the red light emitting element 20R of the organic EL device of the present embodiment will be described. FIG. 4 is a sectional view schematically showing each layer constituting the red light emitting element 20R together with the red color filter 30R and the like. In the red light emitting element 20R, only the transparent layer 81 is formed between the anode 56 and the reflective layer 58, and the semi-reflective layer 82 (see FIG. 3) is not formed.
And the blue light emitting element 20B. Therefore, the interference structure 83 (see FIG. 3)
Is not formed. Further, the color filter 30 is approximately 6 out of the light incident on the display surface 75.
This is a red color filter 30R that transmits light in a wavelength range of a predetermined width centered on 50 nm (that is, a red light component) and absorbs light other than light in the wavelength range of the predetermined width (non-red light component). And RD00 as a dopant of the red light emitting layer 46 included in the red light emitting functional layer 40R.
1 (Idemitsu Kosan Co., Ltd.) is also used. Except for such differences, each component is the same as the component of the green light emitting element 20G shown in FIG. Therefore, the same components are denoted by the same reference numerals, and description thereof is omitted.

Since the red light emitting element 20R does not include the interference structure 83, the reduction of external light reflection is performed by the red color filter 30R and the resonance structure 88. The reason for providing a difference in configuration among the three types of light emitting elements 20 constituting the organic EL device is that a difference in characteristics such as external light reflectance between the light emitting elements 20 is taken into consideration.

As shown in FIGS. 5 to 7 described later, when the interference structure 83 is formed between the anode 56 of the red light emitting element 20R and the reflective layer 58, the red color filter 30R has a long wavelength (wavelength range is approximately 6).
The effect of reducing the external light reflectance in light of 00 nm to 660 nm is small and does not contribute much to the reduction of external light reflection. Therefore, in the organic EL device of this embodiment, the configuration of the three types of light emitting elements is not shared, and the effects of the color filter 30 and the like are combined to reduce external light reflectance and power consumption as a whole. Both are compatible at a high level.

Specifically, the color filter 30 is disposed on all three types of light emitting elements 20, and external light reflection is reduced as much as possible by the color filter. Furthermore, the resonance length of the resonance structure 88 is set with an emphasis on reducing external light reflection. And about the light emitting element 20 which cannot fully reduce external light reflection by the above-mentioned two means, by forming the interference structure 83 between the light emitting functional layer 40 and the reflective layer 58, the extraction efficiency is affected as much as possible. As a result, the reflection of external light is further reduced and the display quality in a bright place as the whole organic EL device is improved.

The effect of reducing external light reflection in the organic EL device according to the present embodiment will be described with reference to FIGS. FIG. 5 is a diagram showing the external light reflectance for each light emitting element 20 of the organic EL device that does not include the color filter 30. The relationship between an external light reflectance and a wavelength at the time of forming the interference structure 83 in each of three types of light emitting elements 20 is shown. For the red light emitting element 20R, the interference structure 83
It also shows the external light reflectivity in the case of not having.

The blue light emitting element 20B and the green light emitting element 20G have a considerably reduced external light reflectance with respect to light in a wavelength range of approximately 500 nm to 550 nm. However, the red light emitting element 20R is not significantly reduced. The red light emitting element 20R not provided with the interference structure 83 has a high external light reflectance of light in the wavelength range of 650 nm or more included in the wavelength range of the emitted light, but has almost no visibility for light having a wavelength of 700 nm or more. Therefore, there is no need to consider external light reflection.

FIG. 6 is a diagram showing the transmission characteristics of the color filter 30 used in the organic EL device of this embodiment. It can be seen that light deviating from the wavelength range of light desired to be emitted from each light emitting element 20 hardly passes through the color filter. Therefore, the effect of reducing the external light reflectance with respect to the deviated light is great.

FIG. 7 is a diagram showing the external light reflectance for each (three types) of light emitting elements 20 constituting the organic EL device of the first embodiment. The reflectance is corrected for visibility. The effect of reducing the external light reflectance by combining the color filter (CF) 30 and the interference structure 83 is shown.
For the red light emitting element 20R, the measurement result of the light emitting element 20 provided with the interference structure 83 is shown as a comparison together with the measurement result of the light emitting element 20 not provided with the interference structure 83 in the present embodiment. In addition, the result of the comparative example 3 of Table 1 mentioned later is organic E of 1st Embodiment.
It is a measurement result at the time of changing the red light emitting element 20R of L apparatus into the light emitting element 20 provided with the above-mentioned interference structure 83. FIG.

The external light reflectance of the red light emitting element 20R is lower when the interference structure 83 is not provided. As shown in FIG. 5, the reflection of light having a wavelength of 600 nm or more is lower when the interference structure 83 is not provided, and light having a wavelength of 600 nm or less is reflected by the red color filter 30R.
This is because the inward incidence is reduced. The remaining two light emitting elements have a slightly high external light reflectance of the green light emitting element 20G, but are good overall. Therefore, as a whole, an organic EL device in which power consumption and external light reflectance are balanced can be obtained.

(Comparative example)
8 and 9 are schematic cross-sectional views showing the organic EL device of Comparative Example 1 that does not have the semi-reflective layer 82 and in which the interference structure 83 is not formed on all three types of light-emitting elements 20. The basic configuration excluding the configuration of the light emitting functional layer 40 and the presence or absence of the semi-reflective layer 82 is the organic EL of the first embodiment shown in FIG.
It is the same as the device. Therefore, the same reference numerals are given to the common components. The organic EL device shown in FIG. 8 is similar to the organic EL device of the first embodiment shown in FIG.
A total of three types of light emitting elements of 0B, the green light emitting element 20G, and the red light emitting element 20R are provided with different light emitting functional layers 40, respectively.

Unlike the organic EL device according to the first embodiment shown in FIG. 2, the organic EL device shown in FIG. 9 includes a white light emitting functional layer 40 </ b> W common to the three types of light emitting elements 20. White light emitting functional layer 40W
Except that it has a light emitting layer in which a total of three layers of a layer using BD052 as a dopant, a layer using quinacridone as a dopant, and a layer using RD001 as a dopant are stacked. The configuration is the same as that of the layer 40G.

In both organic EL devices, the resonance length is set in consideration of both improvement in extraction efficiency and reduction in external light reflection, as in the organic EL device of the first embodiment. The layer thickness of the light emitting functional layer 40 is approximately 94 nm which is common among the three types of light emitting elements 20. The transparent layer 81 is formed of silicon nitride, and the layer thickness is approximately 90 nm which is common among the three types of light emitting elements 20. The anode 56 is made of ITO and has a layer thickness of about 27 nm for the blue light emitting element 20B and about 43.2n for the green light emitting element 20G.
m, the red light emitting element 20R is approximately 86.2 nm.

10 shows each light emitting element 20 constituting the organic EL device of Comparative Example 1 shown in FIGS.
It is a figure which shows the external light reflectance. In the organic EL device of Comparative Example 1, the external light reflectance and the power consumption are substantially the same value even if the configuration of the light emitting functional layer 40 is different. The external light reflectance of the red light emitting element 20R is the same value as the reflectance in the first embodiment. Further, the blue light emitting element 20B is slightly increased but is at an acceptable level. However, the green light emitting element 20G shows a considerably higher value than the other light emitting elements, indicating that the reduction of external light reflection is not complete only by optimizing the color filter 30 and the resonance length.

In the organic EL device according to the present embodiment, the color filter 30 and the interference structure 83 are combined as necessary in consideration of the difference in characteristics between the light emitting elements 20. Furthermore, by setting the optical distance of the resonance structure 88, that is, the resonance length, taking into account the reduction of external light reflection (not only the extraction efficiency), an organic material that balances power consumption and external light reflectance can be obtained. An EL device has been obtained.

FIG. 11 shows the external light reflectance of an organic EL device in which the resonance length is set with priority on the extraction efficiency as Comparative Example 2. This organic EL device includes substantially the same components as the organic EL device shown in FIG. 8 or the organic EL device shown in FIG. The layer thickness of each component is substantially the same as the organic EL device shown in FIG. 8 or the organic EL device shown in FIG. 9 except for the layer thickness of the anode 56. The layer thickness of the anode 56 is approximately 27 nm for the blue light emitting element 20B, approximately 64.8 nm for the green light emitting element 20G, and approximately 108 nm for the red light emitting element 20R. Thus, the resonance length of the resonance structure 88 is set by changing the layer thickness of the anode 56.

As shown in FIG. 11, the organic E in which the resonance length of the resonance structure 88 is set giving priority to the extraction efficiency.
Of the three types of light emitting elements 20 included in the L device, the external light reflectance of the blue light emitting element 20B is at an acceptable level. However, the external light reflectance of the light emitting elements 20 of the other two colors (two types) is very high, and it can be inferred that the display quality in a bright place is at an unacceptable level.

This result is attributed to the characteristics of the color filter 30, that is, it is difficult to reduce external light reflection in the wavelength range that each light emitting element 20 should emit. Therefore, color filter 3
When 0 is used as a means for reducing external light reflection, it must be used in combination with some other means. As described above, the organic EL device according to the present embodiment sets the resonance length of the resonance structure 88 in addition to the color filter 30 with an emphasis on reducing external light reflection, and particularly has high external light reflectivity. By forming the interference structure 83 in the two types of light emitting elements 20, both reduction of external light reflection and reduction of power consumption are achieved.

表１に、第１の実施形態の有機ＥＬ装置及び上述の比較例の有機ＥＬ装置の、外光反射
率と消費電力の測定結果を示す。消費電力は、比較例１（本表の３行目）の有機ＥＬ装置
の消費電力を１とした場合の相対消費電力である。消費電力が小さいということは、取り
出し効率が高いことを意味している。外光反射率は正面での正反射率（視感度補正済み）
である。

Table 1 shows the measurement results of the external light reflectance and the power consumption of the organic EL device of the first embodiment and the organic EL device of the comparative example described above. The power consumption is relative power consumption when the power consumption of the organic EL device of Comparative Example 1 (the third row in this table) is 1. Small power consumption means high extraction efficiency. Outside light reflectance is regular reflectance in front (visibility corrected)
It is.

The measurement result shown in the first row is the organic EL device according to the present embodiment, that is, the optical path length of the resonance structure 88 is set with an emphasis on reducing external light reflection, and the blue light emitting element 20B and the green light emitting element 20 are set.
It is a measurement result of the organic EL device in which the interference structure 83 is formed on G. The measurement result shown in the second row is the measurement result of the organic EL device of the second embodiment described later.

The measurement result of Comparative Example 3 shown in the fifth row is the measurement result of the organic EL device in which the interference structure 83 is formed on all three types of light emitting elements 20 including the red light emitting element 20R. The red light emitting element 20
The difference in external light reflectance between when the interference structure 83 is formed on R and when it is not formed is as shown in FIG. Further, the measurement result of Comparative Example 2 shown in the fourth row is a value in the organic EL device in which the resonance length of the resonance structure 88 is set giving priority to the extraction efficiency shown in FIG. The organic EL device according to the present embodiment reduces the external light reflectance to the lowest level while keeping the power consumption at a relatively low level, and reduces the power consumption and the display quality such as contrast in a bright place. It can be seen that the improvement is compatible at a high level.

(Second Embodiment)
FIG. 12 is a schematic cross-sectional view of an organic EL device according to the second embodiment. The organic EL device according to the present embodiment is a top emission type organic EL that emits light toward the counter substrate 11.
Device. The organic EL device according to this embodiment has a configuration similar to that of the organic EL device according to the first embodiment. Therefore, common constituent elements are given the same reference numerals, and descriptions thereof are omitted. The difference in configuration from the organic EL device of the first embodiment is two points, the presence / absence of the interference structure 83 and the configuration of the light emitting functional layer 40. Of the three types of light emitting elements, only the green light emitting element 20 </ b> G includes the interference structure 83. As for the light emitting functional layer 40, as in the organic EL device of the comparative example shown in FIG. 9, the dopant common to the three types of light emitting elements is BD052.
A white light emitting functional layer 40W in which a total of three layers, a layer using quinacridone, a layer using quinacridone and a layer using RD001, are stacked.

Further, the layer thickness of each component is the same as that of the transparent layer 81 and the semi-reflective layer 82 constituting the interference structure 83 and the layer thickness of ITO constituting the anode 56 as the first electrode of the first embodiment. It differs from the value in the organic EL device. Specifically, the transparent layer 81 is made of silicon nitride having a thickness of about 90 nm, and the semi-reflective layer 82 is made of titanium having a thickness of about 15 nm. The layer thickness of the anode 56 is approximately 32.4 nm for the blue light emitting element 20B and approximately 21.6 nm for the green light emitting element 20G, and the layer thickness of the red light emitting element 20R is approximately the same as that of the organic EL device of the first embodiment. 92 nm. For other components, the material, layer thickness, etc. are the same as the material, layer thickness, etc. of the organic EL device of the first embodiment.

FIG. 14 shows the external light reflectance of each light emitting element 20 constituting the organic EL device of the present embodiment. For comparison, FIG. 13 shows the external light reflectance of each light emitting element 20 when the color filter 30 is removed from the organic EL device of the second embodiment.

As shown in FIG. 13, when the color filter 30 is omitted, the reflectance of outside light in the wavelength range that transmits the color filter 30 becomes very high, which is not practical. Such a phenomenon is also attributed to the fact that the resonance length of the resonance structure 88 is set on the assumption that the color filter 30 exists. However, even if the resonance length setting focuses on the reduction of external light reflection and the interference structure 83 is formed on the green light emitting element 20G, it can be confirmed that the reduction of the external light reflection is incomplete. On the other hand, as shown in FIG. 14, when the color filter 30 is disposed, the external light reflectance is suppressed to a low level in all three types of light emitting elements 20.

The values of the external light reflectance and power consumption of the organic EL device of this embodiment are as described in the second row of Table 1 above. Although the external light reflectance is slightly higher than the value of the organic EL device of the first embodiment, the interference structure 83 is formed in all the light emitting elements as Comparative Example 3 described in the fifth row of Table 1 above. The level is equivalent to that of an organic EL device. On the other hand, power consumption is 5 types of organic E including comparative examples.
It shows the second lowest value in the L device, and it can be seen that the extraction efficiency is improved.
Therefore, the organic EL device according to the present embodiment improves the extraction efficiency while reducing the external light reflectance to an acceptable level, and, like the organic EL device of the first embodiment, reduces power consumption. It provides a high level of improvement in display quality in daylight.

(Third embodiment)
FIG. 15 is a schematic cross-sectional view of an organic EL device according to the third embodiment. The organic EL device according to the present embodiment is a top emission type organic EL that emits light toward the counter substrate 11.
Device. The organic EL device according to this embodiment has a configuration similar to that of the organic EL device according to the first embodiment. The light emitting functional layer 40 is provided on the blue light emitting element 20B.
B, a green light emitting functional layer 40G is formed separately for the green light emitting element 20G, and a red light emitting functional layer 40R is formed separately for the red light emitting element 20R. An interference structure 83 is formed between the blue light emitting element 20B and the green light emitting element 20G. Therefore, common constituent elements are given the same reference numerals, and descriptions thereof are omitted.

The difference from the organic EL device of the first embodiment is the configuration of the interference structure 83. The organic EL device of the present embodiment does not include the transparent layer 81, and an interference structure 83 is formed by the anode 56 as the first electrode and the semi-reflective layer 82. As shown in the figure, a semi-reflective layer 82 is formed on the surface of the anode 56 on the side of the counter substrate 11 in the blue light emitting element 20B and the green light emitting element 20G.

As described above, since the anode 56 is made of ITO, which is a transparent conductive material, in addition to the function as an electrode, the same function as the transparent layer 81 in the organic EL device of the first embodiment,
That is, the optical distance between the surface of the semi-reflective layer 82 (interface between the semi-reflective layer 82 and the light emitting functional layer 40) and the surface of the reflective layer 58 (interface between the reflective layer 58 and the anode 56) is also adjusted. Can fulfill. Therefore, as described above, the semi-reflective layer 82 is formed on the surface of the anode 56 facing the counter substrate 11.
Thus, the interference structure 83 can be formed between the reflective layer 58 and the light emitting functional layer 40 such as the green light emitting functional layer 40G without forming the transparent layer 81 (see FIG. 2).

The interference structure 83 is configured by setting the optical distance (of the laminate of the anode 56 and the semi-reflective layer 82) to be approximately a quarter of the wavelength of light for which external light reflection is desired to be reduced. As with the interference structure 83 in the first embodiment, external light reflection can be reduced. That is, the color filter 3
Approximately 50% of the light transmitted through 0 and reaching the semi-reflective layer 82 is reflected by the surface of the semi-reflective layer 82 (the interface between the semi-reflective layer 82 and the light emitting functional layer 40), and the remaining approximately 50% is reflected. By reflecting on the surface of the reflective layer 58 (the interface between the reflective layer 58 and the anode 56), the phases of both lights can be shifted by 180 degrees and cancel each other. Therefore, the organic EL device of this embodiment has a display quality in a bright place equivalent to that of the organic EL device of the first embodiment, while reducing the manufacturing cost by reducing the thin film forming process and the thin film patterning process. Reduction is possible.

Note that the layer thickness of the anode 56 of the organic EL device of the present embodiment is approximately 21 in the blue light emitting element 20B.
3 nm, approximately 111 nm for the green light emitting element 20G, and approximately 175 nm for the red light emitting element 20R. The above values are adjusted according to the layer thickness or refractive index of the light emitting functional layer 40, and are displayed as the entire organic EL device including the effect of reducing the external light reflectance by optimizing the resonance length of the resonance structure 88 described above. It is preferable to improve the quality.

(Fourth embodiment)
FIG. 16 is a schematic cross-sectional view of an organic EL device according to the fourth embodiment. The organic EL device according to the present embodiment is a top emission type organic EL that emits light toward the counter substrate 11.
Device. Constituent elements common to those of the organic EL device of the first embodiment and the organic EL device of the third embodiment described above are given the same reference numerals, and description thereof is omitted. The “common component” means that the forming material is the same unless otherwise specified.

In the organic EL device according to this embodiment, the light emitting functional layer 40 is individually formed on the three types of light emitting elements 20, and the interference structure 83 is formed on the blue light emitting element 20B and the green light emitting element 20G. This is common to the organic EL device of the third embodiment described above. Further, the organic EL device of the third embodiment is also common in that a semi-reflective layer 82 is formed on the surface of the anode 56 on the counter substrate 11 side.

The difference from the organic EL device of the third embodiment is that the transparent layer 8 is interposed between the anode 56 and the reflective layer 58.
1 is formed. In the organic EL device of the present embodiment, the transparent layer 81, the anode 56, and the semi-reflective layer 82 formed in the order described in the surface of the reflective layer 58 on the counter substrate 11 side,
An interference structure 83 is configured. That is, in the organic EL device of the present embodiment, the transparent layer 81
And the anode 56 function as the transparent layer 81 in the organic EL device of the first embodiment.

As described above, in the organic EL device according to the first embodiment, a total of three layers of the transparent layer 81, the semi-reflective layer 82, and the anode 56 are formed between the reflective layer 58 and the light emitting functional layer 40. . The organic EL device of this embodiment is also common in that the above three layers are formed. By forming the transparent layer 81 between the reflective layer 58 and the anode 56, the thickness of the transparent layer 81 can be reduced, and the time required for thin film formation and patterning of the thin film can be reduced. In addition, the electrolytic corrosion phenomenon that can occur between the reflective layer 58 and the anode 56 can be suppressed.

(Fifth embodiment)
FIG. 17 is a schematic cross-sectional view of an organic EL device according to the fifth embodiment. The organic EL device according to this embodiment is a bottom emission type organic EL device that emits light in the direction of the element substrate 10, unlike the organic EL devices of the first to fourth embodiments described above. Therefore, as will be described later, the cathode 155 is the first electrode, the anode 156 is the second electrode, and the interference structure 83.
Is formed between the cathode 155 and the light emitting functional layer 40. The element substrate 10 is made of a translucent material.
In addition, the same code | symbol is provided to the component which is common in the component of the organic electroluminescent apparatus of 1st Embodiment except the said pair of electrode. Hereinafter, the difference from the organic EL device of the first embodiment will be mainly described, and description of the common points will be omitted.

In the organic EL device of the present embodiment, the color filter 30 is also formed on the element substrate 10 side in accordance with the light emission direction. Specifically, the blue color filter 30B, the green color filter 30G, and the red color are formed on the surface of the second interlayer insulating layer 73 on the counter substrate 11 side, that is, on the interface between the second interlayer insulating layer 73 and the third interlayer insulating layer 74. Three types of color filters 30 of the filter 30 </ b> R are formed so as to correspond to the respective light emitting elements 20. Since the light generated in the light emitting functional layer 40 passes through the color filter 30 and is emitted from the element substrate 10 side, the interface between the color filter 30 and the second interlayer insulating layer 73 is defined as a display surface 75. .

The black matrix 35 (see FIG. 2) is not formed, and the driving TFT 112 and the scanning line 102, the signal line 104, etc. (see FIG. 1) formed between the driving TFTs shield light between the pixel regions. Plays a function.

As in the organic EL device of the first embodiment, the light emitting functional layer 40 includes a blue light emitting functional layer 40B for the blue light emitting element 20B, a green light emitting functional layer 40G for the green light emitting element 20G, and a red light emitting element 2.
The red light emitting functional layer 40R is individually formed in 0R. The configuration of the light emitting functional layer 40 and the material for forming each layer are the same as those of the organic EL device of the first embodiment.

The organic EL device according to the present embodiment includes a resonance structure 88 (see FIG. 3) in the same manner as the organic EL devices according to the first to fourth embodiments described above. The cathode 155 as the first electrode has a layer thickness of about 100 nm.
Made of Al and also serves as a reflective layer. And this cathode is the light emitting functional layer 4 mentioned later.
Of the light generated at 0, all the light directed toward the counter substrate 11 is reflected toward the element substrate 10 side.

The anode 156 as the second electrode is made of ITO, and the second semi-reflective layer 57 is formed on the element substrate 10 side of the anode. The second semi-reflective layer 57 is made of Al having a layer thickness of about 8 nm,
Approximately 50% of the light generated in the light emitting functional layer 40 and the light reflected by the cathode 155 is reflected, and the remaining approximately 50% is transmitted and emitted from the display surface 75. Therefore, the cathode 155 and the second
A resonant structure is formed between the semi-reflective layer 57. The reflection of external light can be reduced by adjusting the optical path length of the resonant structure. A protective layer made of silicon nitride or the like may be formed between the cathode 155 and the second semi-reflective layer 57.

In the organic EL device of the present embodiment, an interference structure 83 is formed in the blue light emitting element 20B and the green light emitting element 20G, similarly to the organic EL device of the first embodiment. Organic E of this embodiment
Since the L device is a bottom emission type, as described above, the interference structure 83 is formed between the cathode 155 that also serves as the reflective layer and the light emitting functional layer 40.

A semi-reflective layer 82 made of titanium is formed on the counter substrate 11 side of the blue light emitting functional layer 40B and the counter substrate 11 side of the green light emitting functional layer 40G. A transparent layer 81 is formed over the entire display region 100 (see FIG. 1) on the counter substrate 11 side of the semi-reflective layer. The transparent layer is made of ITO, which is a transparent conductive material, and is conductive between the cathode 155 and the anode 156, that is, between the cathode 155 and the anode 156 via the light emitting functional layer 40 and the like. Ensures electrical conductivity. With this configuration, the blue light emitting element 20B and the green light emitting element 20
An interference structure 83 composed of a transparent layer 81 and a semi-reflective layer 82 is formed between the G cathode 155 and the light emitting functional layer 40 via the electron injection layer 54. It may be considered that the interference structure 83 is configured by a total of three layers of the electron injection layer 54, the transparent layer 81, and the semi-reflective layer 82.

The interference structure exhibits the same function as the interference structure 83 provided in the organic EL device of the first embodiment shown in FIG. That is, external light that has passed through the color filter 30 and the anode 156 and reached the interface between the light-emitting functional layer 40 and the semi-reflective layer 82 is converted into the surface of the semi-reflective layer 82 (the interface between the light-emitting functional layer 40 and the semi-reflective layer 82). ) And the surface of the cathode 155 (the cathode 155 and the electron injection layer 54)
The external light reflectivity can be reduced by dividing the light into two that are reflected at the interface between the two and canceling each other.

In the organic EL device of the present embodiment, since the interference structure 83 is formed on the cathode 155 side in accordance with the light emission direction, approximately 50% of the light emission generated in the light emitting functional layer 40 is affected by the interference structure. Without being emitted from the display surface 75. Therefore, it is possible to reduce the external light reflectance while suppressing a decrease in extraction efficiency.

(Modification 1)
In the organic EL device according to the first embodiment described above, the optical path length of the interference structure 83 is set to be equal to the blue light emitting element 2.
0B and the green light emitting element 20G are set to be the same. However, the optical path length need not be common among the light emitting elements. Since the wavelength range of the external light (second external light component 92) transmitted through the color filter varies depending on the light emitting element 20, the optical path length is set according to the difference.
It can also be set every zero. By increasing the thin film forming process (and the thin film patterning process, etc.) once, the interference structure 83 having different optical path lengths can be formed in the blue light emitting element 20B and the green light emitting element 20G.

(Modification 2)
The organic EL devices of the first to fifth embodiments described above include three types of light emitting elements 20, blue, green,
A color image is formed by mixing light of three primary colors of red. However, the type of the light emitting element is not limited, and in addition to the three primary colors, for example, a light emitting element that emits white light can be provided.

1 is a circuit configuration diagram showing an overall configuration of an organic EL device according to a first embodiment. 1 is a schematic cross-sectional view of an organic EL device according to a first embodiment. The cross-sectional view of a green light emitting element. The cross-sectional view of a red light emitting element. The figure which shows the external light reflectance for every light emitting element of the organic electroluminescent apparatus which is not provided with the color filter. The figure which shows the permeation | transmission characteristic of a color filter. The figure which shows the external light reflectance for every light emitting element of the organic electroluminescent apparatus of 1st Embodiment. The schematic cross section which shows the organic electroluminescent apparatus as a comparative example. The schematic cross section which shows the organic electroluminescent apparatus as a comparative example. The figure which shows the external light reflectance for every light emitting element of the organic electroluminescent apparatus of the comparative example 1. FIG. The figure which shows the external light reflectance for every light emitting element of the organic electroluminescent apparatus of the comparative example 2. FIG. The schematic cross section of the organic electroluminescent apparatus concerning 2nd Embodiment. The figure which shows the external light reflectance for every light emitting element at the time of removing a color filter from the organic electroluminescent apparatus of 2nd Embodiment. The figure which shows the external light reflectance for every light emitting element of the organic electroluminescent apparatus of 2nd Embodiment. The schematic cross section of the organic electroluminescent apparatus concerning 3rd Embodiment. The schematic cross section of the organic electroluminescent apparatus concerning 4th Embodiment. FIG. 10 is a schematic cross-sectional view of an organic EL device according to a fifth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Element substrate, 11 ... Opposite substrate, 12 ... Adhesive layer, 20B ... Blue light emitting element, 20G ... Green light emitting element, 20R ... Red light emitting element, 29 ... Color filter layer, 30B ... Blue color filter, 30G ... Green color filter 30R ... red color filter, 35 ... black matrix, 40B ... blue light emitting functional layer, 40G ... green light emitting functional layer, 40R ... red light emitting functional layer,
40W ... white light emitting functional layer, 44 ... green light emitting layer, 46 ... red light emitting layer, 51 ... hole injection layer, 5
2 ... hole transport layer, 53 ... electron transport layer, 54 ... electron injection layer, 55 ... cathode as second electrode,
56... Anode as first electrode 57. Second semi-reflective layer 58. Reflective layer 59 59 Sealing layer 60
... Channel region, 62 ... Gate electrode, 64 ... Drain electrode, 66 ... Source electrode, 71 ... Gate insulating film, 72 ... First interlayer insulating layer, 73 ... Second interlayer insulating layer, 74 ... Third interlayer insulating layer, 7
5 ... display surface, 77 ... partition, 81 ... transparent layer, 82 ... semi-reflective layer, 83 ... interference structure, 85 ... outgoing light, 86 ... first light emission, 87 ... second light emission, 88 ... resonance structure, 90 ... external light, 91 ... first external light component, 92 ... second external light component, 93 ... reflected light, 94 ... first reflected light, 95 ... second reflected light, 100 ... display region, 102 ... Scanning line 104 ... Signal line 106 ... Power supply line 10
DESCRIPTION OF SYMBOLS 8 ... Switching TFT, 110 ... Holding capacitor, 112 ... Driving TFT, 120 ... Scanning line driving circuit, 130 ... Signal line driving circuit, 140 ... Synchronization signal line, 155 ... Cathode as first electrode, 156 ... Second Anode as electrode.

Claims (11)

A light emitting device comprising a plurality of types of light emitting elements including at least a red light emitting element that emits red light, a green light emitting element that emits green light, and a blue light emitting element that emits blue light;
Each of the plurality of types of light emitting elements is:
A first electrode;
A second electrode having transflective or transmissive properties disposed on the light emitting side;
A functional layer including at least a light emitting layer sandwiched between the first electrode and the second electrode;
A reflective layer that is formed at a position facing the functional layer across the first electrode and reflects the light generated in the light emitting layer toward the second electrode;
A color filter that absorbs light in a wavelength region other than the wavelength region of the emitted light, disposed at a position facing the reflective layer across the functional layer;
With
At least one of the plurality of types of light emitting elements is:
Of the external light component that is disposed between the reflective layer and the functional layer and passes through the color filter included in the one type of light-emitting element and is incident on the functional layer side, a part is used as the first reflected light. A semi-reflective layer that reflects and transmits the remaining part ;
The reflective layer reflecting the remaining portion as second reflected light ;
A transparent layer disposed between the semi-reflective layer and the reflective layer ;
Further comprising an interference structure in which the thickness of the transparent layer is designed so that the first reflected light and the second reflected light cancel each other .
A light-emitting device, wherein a red light-emitting element among the plurality of types of light-emitting elements does not include the interference structure . A light emitting device comprising a plurality of types of light emitting elements including at least a red light emitting element that emits red light, a green light emitting element that emits green light, and a blue light emitting element that emits blue light;
Each of the plurality of types of light emitting elements is:
A first electrode also serving as a reflective layer;
A second electrode having transflective or transmissive properties disposed on the light emitting side;
A functional layer including at least a light-emitting layer sandwiched between the first electrode and the second electrode;
A color filter that absorbs light in a wavelength region other than the wavelength region of the emitted light, disposed at a position facing the first electrode across the functional layer;
With
At least one kind of light emitting element among the plurality of kinds of light emitting elements is:
A part of the external light component that is disposed between the first electrode and the functional layer and passes through a color filter included in the one type of light emitting element and enters the functional layer side is a first reflected light. A semi-reflective layer that reflects as and transmits the remaining part ,
The first electrode reflecting the remaining portion as second reflected light ;
A transparent layer disposed between the semi-reflective layer and the first electrode ;
Further comprising an interference structure in which the thickness of the transparent layer is designed so that the first reflected light and the second reflected light cancel each other .
A light-emitting device, wherein a red light-emitting element among the plurality of types of light-emitting elements does not include the interference structure . The light-emitting device according to claim 1 or 2,
The light emitting device, wherein the plurality of types of light emitting elements are three types of light emitting elements: the red light emitting element, the green light emitting element, and the blue light emitting element. The light-emitting device according to claim 3,
Only the green light emitting element includes the semi-reflective layer.   4. The light emitting device according to claim 3, wherein two types of light emitting elements, the green light emitting element and the blue light emitting element, include the semi-reflective layer. The light emitting device according to any one of claims 1 to 5,
The light emitting device, wherein the light emitting layer is an organic electroluminescence layer. The light-emitting device according to any one of claims 1 to 6 ,
The semi-reflective layer is made of any one of titanium, chromium, tantalum, and molybdenum. A light emitting device according to any one of claims 1,3～ 7,
The light-emitting device, wherein the first electrode is an anode and the second electrode is a cathode. The light-emitting device according to claim 8 ,
The anode is made of a transparent conductive material,
The light emitting device, wherein the transparent layer and the semi-reflective layer are formed between the reflective layer and the first electrode. The light-emitting device according to claim 8 ,
The transparent layer is made of a conductive material and serves also as the first electrode. The light-emitting device according to claim 8 ,
The transparent layer is a transparent conductive material layer also serving as the transparent insulating material layer disposed on the functional layer side of the reflective layer and the first electrode disposed on the functional layer side of the transparent insulating material layer. And a light emitting device comprising:

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