JP2013012493A - Color display device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color display device which is capable of high definition display and can be manufactured easily, and a manufacturing method therefor.SOLUTION: The color display device comprises a plurality of pixels on a substrate, each pixel being composed of at least two kinds of sub-pixels emitting light in visible range differing in wavelength and a white sub-pixel. The at least two kinds of sub-pixels and the white sub-pixel each include an optical path length adjustment layer and a white light-emitting organic electroluminescent layer held between a light semi-transmissive reflection layer and a light reflection layer, forming a resonator in which an optical distance between the light semi-transmissive reflection layer and the light reflection layer in the at least two kinds of sub-pixels is the distance which resonates the respectively emitted rays of light. An optical distance between the light semi-transmissive reflection layer and the light reflection layer in the white sub-pixel is longer than the maximum length of the optical distance between the light semi-transmissive reflection layer and the light reflection layer in the at least two kinds of sub-pixels.

Description

  The present invention relates to a color display device using a light emitting element and a manufacturing method thereof.

  In recent years, thin and light flat panel displays have been used in a wide range of fields in place of cathode ray tubes (CRT), and their applications have been extended. This is because personal information terminals such as personal computers and network access compatible mobile phones have been acceleratingly spread with the development of information equipment and infrastructure for service networks centered on the Internet. In addition, the market for flat panel displays has been expanding to home TVs, which have traditionally been exclusive to CRTs.

  Among them, an organic electroluminescence element (in some cases, abbreviated as “organic EL element” in the following description) is a device that has attracted particular attention in recent years. An organic EL element is an element that emits light in response to an electric signal and is configured using an organic compound as a light-emitting substance. Organic EL elements inherently have excellent display characteristics such as a wide viewing angle, high contrast, and high-speed response. In addition, since there is a possibility of realizing thin and light and high-quality display devices from small to large, it has been attracting attention as an element replacing CRT and LCD.

Various full-color display devices using organic EL elements have been proposed.
For example, as means for obtaining three basic colors of red (R), green (G), and blue (B) for full color expression, there are a three-color painting method and a method of combining a color filter with a white organic EL.

  In the three-color coating method, there is a possibility that the efficiency can be improved by preparing materials suitable for three colors as coloring materials and reducing the loss of the circularly polarizing plate. However, since the painting technique is difficult, it is difficult to realize a high-definition display and it is difficult to enlarge the screen.

In the method of obtaining three colors by combining a color filter with a white organic EL element, there are problems that the luminous efficiency of the white light emitting material itself is low and that the luminance is reduced to about 1/3 by the color filter.
In addition, various improvements have been made in the method of obtaining a desired color by converting the light emitted from the organic EL element using a color conversion film, but there are problems such as low conversion efficiency to red. .

On the other hand, a semi-transparent cathode is adopted for the upper electrode, and it is considered to realize high color reproducibility by taking out only light of a specific wavelength outside the organic EL element by the multiple interference effect with the reflective film. Has been. For example, an organic layer configured such that a first electrode made of a light reflecting material, an organic layer having an organic light emitting layer, a translucent reflecting layer, and a second electrode made of a transparent material are sequentially laminated so that the organic layer becomes a resonance part. In the EL element, there is known an organic EL element configured to satisfy the following formula, where λ is the peak wavelength of the spectrum of light to be extracted.
(2L) / λ + Φ / (2π) = m
(L is an optical distance, λ is a wavelength of light to be extracted, m is an integer, Φ is a phase shift, and the optical distance L is a positive minimum value)

  For example, an organic EL display device provided with a microcavity (microresonator) is disclosed (for example, see Patent Document 1). Specifically, one pixel is subdivided into red (R), green (G), and blue (B) sub-pixels, and the light emitted from each is resonated between the light transflective electrode and the reflective film (electrode). It is said that a simple full-color display device can be obtained by constituting a resonator and using an organic EL light emitting layer in common, which eliminates the need for three-color coating and does not require a color filter. A resonator is not provided in the white sub-pixel portion. This is because the principle of a resonator that resonates only at a specific wavelength is not suitable for emitting white light having an emission spectrum in the entire visible range. However, for that purpose, the light transflective electrode is changed to a transparent electrode, and it is necessary to paint it separately from the R, G, B subpixels. Therefore, high definition becomes difficult, and the manufacturing process becomes complicated, which is not preferable.

  In addition, a light emitting device is disclosed in which a resonator structure is formed by changing the thickness of the anode of the organic electroluminescent layer to extract R, G, B light (see, for example, Patent Document 2). A transparent conductive material such as ITO is used as the anode, and a light reflecting film is provided below the anode via a transparent insulating layer.

  In full-color display devices, white subpixels are important for achieving both abundant color reproduction and gradation reproduction and low power consumption, and it is desirable to solve the problems associated with installing white subpixels. Yes.

Published patent 2007-503093 JP 2006-269329 A

  An object of the present invention is to provide a color display device using a light emitting element and a manufacturing method thereof. In particular, it is to provide a color display device capable of high-definition color display and easy to manufacture and a method for manufacturing the same.

It has been found that the above-mentioned problems of the present invention can be solved by the following means.
<1> A color display device that includes a plurality of pixels on a substrate, and each pixel includes at least two types of sub-pixels and white sub-pixels that emit light having different wavelengths in the visible range. Each of the sub-pixel and the white sub-pixel has a white light-emitting organic electroluminescent layer sandwiched between a light semi-transmissive reflective layer and a light reflective layer, and the light semi-transmissive reflective layer in the at least two types of sub-pixels An optical distance between the light reflection layer and the light reflection layer is formed to form a resonator having a distance that resonates emitted light, and an optical distance between the light transflective layer and the light reflection layer in the white subpixel is formed. The color display device, wherein the distance is longer than the longest optical distance of the optical distance between the light transflective layer and the light reflective layer in the at least two types of subpixels.
<2> The at least two types of subpixels include a red subpixel, a green subpixel, and a blue subpixel, and the light transflective layer and the light reflective layer in the red subpixel, the green subpixel, and the blue subpixel The color display device according to <1>, wherein the optical distances between and are the distances at which red light, green light, and blue light resonate.
<3> The optical distance between the light transflective layer and the light reflective layer in the white subpixel is between the light transflective layer and the light reflective layer in the at least two types of subpixels. The color display device according to <1> or <2>, wherein the optical distance is longer than the longest optical distance by at least twice.
<4> The optical distance between the light transflective layer and the light reflective layer in the white subpixel is 2.0 μm or more, and any one of <1> to <3> The color display device described.
<5> The at least two types of subpixels and white subpixels have a white organic electroluminescent layer having the same composition, and an optical path length adjusting layer between the light transflective layer and the light reflective layer, The color display device according to any one of <1> to <4>, wherein the optical path length adjusting layer has a different thickness.
<6> The substrate is a TFT substrate, and at least one of the sub-pixels has a planarization film on the substrate, and the light reflection layer on the planarization film < The color display device according to any one of 1> to <5>.
<7> The substrate is a TFT substrate, and at least one of the sub-pixels has a planarization film on the substrate, and the planarization film and the substrate or between the planarization film and the planarization film The color display device according to any one of <1> to <5>, further comprising a light reflection layer.
<8> The substrate is a TFT substrate, and has a planarization film on the substrate, and the red subpixel, the green subpixel, and the blue subpixel are arranged on the planarization film, the light reflecting layer, A light transflective layer, and an optical path length adjusting layer and a white light emitting organic electroluminescent layer sandwiched between the light transflective reflective layer and the light reflective layer, wherein the white subpixel includes the substrate and the planarization <6> or <6>, wherein the light reflecting layer is provided between the film and the transparent electrode, the white light emitting organic electroluminescent layer, and the light transflective layer are provided on the planarizing film. 7>. The color display device according to 7>.
<9> The color display device according to <8>, wherein the light reflection layer of the white subpixel is formed of a layer common to the electrode of the TFT.
<10> A red color filter, a green color filter, and a blue color filter are disposed on the light emission side of the red light emission subpixel, the green light emission subpixel, and the blue light emission subpixel, respectively. <2> ~ The color display device according to any one of <9>.

<11> A color display device comprising a plurality of pixels on a substrate, each pixel comprising a red light emitting subpixel, a green light emitting subpixel, a blue light emitting subpixel and a white subpixel, and a TFT for driving each subpixel. In the color display device, the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel are respectively sandwiched between a light transflective layer and a light reflecting layer. An optical distance between the light transflective layer and the light reflecting layer in the red light emitting subpixel, the green light emitting subpixel, and the blue light emitting subpixel; A distance at which each emitted light is resonated, and an optical distance between the light transflective layer and the light reflective layer in the white subpixel is the optical distance between the light transflective layer and the light in the red subpixel. The longest optical distance between the reflective layer A method for manufacturing a color display device, which is longer than the academic distance and has the following steps:
1) A flattening layer is formed by covering the TFTs of the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel,
2) forming a light reflection layer in common with the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel;
3) The optical path length adjustment layer is formed of a material common to the red light-emitting subpixel, the green light-emitting subpixel, the blue light-emitting subpixel, and the white subpixel, with the thickness changed,
4) forming a transparent electrode as a pixel electrode by patterning corresponding to the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel;
5) forming a white organic electroluminescent layer in common with the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel;
6) A light transflective layer is formed in common for the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel.

<12> A color display device comprising a plurality of pixels on a substrate, each pixel comprising a red light emitting subpixel, a green light emitting subpixel, a blue light emitting subpixel and a white subpixel, and a TFT for driving each subpixel. In the color display device, the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel are respectively sandwiched between a light transflective layer and a light reflecting layer. An optical distance between the light transflective layer and the light reflecting layer in the red light emitting subpixel, the green light emitting subpixel, and the blue light emitting subpixel; A distance at which each emitted light is resonated, and an optical distance between the light transflective layer and the light reflective layer in the white subpixel is the optical distance between the light transflective layer and the light in the red subpixel. The longest optical distance between the reflective layer A method for manufacturing a color display device, which is longer than the academic distance and has the following steps:
1) forming a light reflection layer of the white sub-pixel on the same substrate as the substrate on which the TFT is formed;
2) A flattening layer is formed by covering the red light emitting subpixel, the green light emitting subpixel, the TFT of the blue light emitting subpixel and the white subpixel, and the light reflecting layer of the white subpixel,
3) forming a light reflection layer in common with the red light emitting subpixel, the green light emitting subpixel, and the blue light emitting subpixel;
4) The optical path length adjusting layer is formed of a material common to the red light emitting subpixel, the green light emitting subpixel, and the blue light emitting subpixel, and is formed with different thicknesses.
5) forming a transparent electrode as a pixel electrode by patterning corresponding to the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel;
6) forming the white organic electroluminescent layer in common with the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel;
7) The light transflective layer is formed in common for the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel.

<13> A color display device including a plurality of pixels on a substrate, each pixel including a red light emitting subpixel, a green light emitting subpixel, a blue light emitting subpixel, a white subpixel, and a TFT for driving the subpixel. In the color display device, the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel are respectively sandwiched between a light transflective layer and a light reflecting layer. An optical distance between the light transflective layer and the light reflecting layer in the red light emitting subpixel, the green light emitting subpixel, and the blue light emitting subpixel; A distance at which each emitted light is resonated, and an optical distance between the light transflective layer and the light reflective layer in the white subpixel is the optical distance between the light transflective layer and the light in the red subpixel. The longest optical distance between the reflective layer A method for manufacturing a color display device, which is longer than the academic distance and has the following steps:
1) forming a light reflection layer of the white sub-pixel on the same substrate as the substrate on which the TFT is formed;
2) A flattening layer having a first thickness is formed by covering the red light emitting subpixel, the green light emitting subpixel, the TFT of the blue light emitting subpixel and the white subpixel, and the light reflecting layer of the white subpixel,
3) forming a light reflecting layer on the red light emitting subpixel;
4) Forming a planarizing layer having a second thickness by covering the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel and the white subpixel,
5) A light reflecting layer is formed in the green light emitting subpixel,
6) forming a third-thickness planarizing film covering the red light-emitting subpixel, the green light-emitting subpixel, the blue light-emitting subpixel, and the white subpixel;
7) A light reflecting layer is formed in the blue light emitting subpixel,
8) Forming a flattened film having a fourth thickness by covering the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel,
9) A transparent electrode is formed as a pixel electrode by patterning corresponding to the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel,
10) forming the white organic electroluminescent layer in common with the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel;
11) The light transflective layer is formed in common for the red light emitting subpixel, the green light emitting subpixel, the blue light emitting subpixel, and the white subpixel.

According to the present invention, a color display device capable of high-definition color display and easy to manufacture and a manufacturing method thereof are provided. In particular, since the organic electroluminescent layer can be formed in common for all the pixels including the sub-pixels, it is not necessary to paint the organic electroluminescent layer portion separately according to the emission color. Further, the optical path length adjusting layer for forming the resonator structure can be formed by changing the thickness with a common material.
Conventionally, when a resonator structure is provided in the R, G, B subpixels, if a resonator structure is also provided in the white subpixel, a specific wavelength is resonated, so that the white subpixel has a specific color. Color reproduction was difficult. When only the white sub-pixel portion has no resonator structure, the configuration of the apparatus is complicated, the manufacturing process is complicated, and high definition is difficult.
According to the present application, the thickness of the optical path length adjustment layer of the white sub-pixel portion is thicker than the thickness of the optical path length adjustment layer of the red light emitting layer, and substantially does not emit light of a specific color.

It is a conceptual diagram of the pixel arrangement | sequence of a matrix type display apparatus. It is a conceptual diagram which shows the subpixel arrangement | sequence of 1 pixel. It is a schematic sectional drawing of 1 pixel by this invention. It is a schematic sectional drawing which shows another aspect of 1 pixel by this invention. It is a schematic sectional drawing which shows another aspect of 1 pixel by this invention. It is an example of the spectrum of the light inject | emitted from the B subpixel by this invention. It is an example of the spectrum of the light inject | emitted from G subpixel by this invention. It is an example of the spectrum of the light inject | emitted from R subpixel by this invention. It is an example of the spectrum of the light inject | emitted from W subpixel by this invention. It is an example of the spectrum of the light inject | emitted from W subpixel by this invention. It is another example of the spectrum of the light inject | emitted from the W subpixel by this invention.

Hereinafter, the present invention will be described in more detail.
1. Display Device The display device of the present invention includes a plurality of pixels on a substrate, and each pixel includes at least two types of sub-pixels that emit light having different wavelengths in the visible range and a white sub-pixel.
As shown in FIG. 1, the display device of the present invention has a matrix type screen panel in which a plurality of pixels are arranged vertically and horizontally on a substrate. Each pixel is composed of at least two types of sub-pixels and white sub-pixels that emit light having different wavelengths in the visible range, and each pixel forms a resonator. A full color can be reproduced by independently controlling these sub-pixels and emitting light with independent luminance.
Preferably, the configuration includes a red (R) subpixel, a green (G) subpixel, a blue (B) subpixel, and a white pixel (W pixel). FIG. 2 is a conceptual diagram showing the arrangement of sub-pixels.

The display device of the present invention is a color display device that includes a plurality of pixels on a substrate, and each pixel is composed of at least two types of sub-pixels and white sub-pixels that emit light having different wavelengths in the visible range, The at least two types of sub-pixels and the white sub-pixel each have a white light-emitting organic electroluminescent layer sandwiched between a light semi-transmissive reflective layer and a light reflective layer, and the light half-pixel in the at least two types of sub-pixels. A resonator in which the optical distance between the transmissive reflective layer and the light reflective layer is a distance that resonates emitted light is formed, and between the light transflective layer and the light reflective layer in the white subpixel. The optical distance is longer than the longest optical distance of the optical distance between the light transflective layer and the light reflective layer in the at least two types of sub-pixels.
Preferably, at least two types of subpixels include a red subpixel (R subpixel), a green subpixel (G subpixel), and a blue subpixel (B subpixel), and the red subpixel, the green subpixel, The optical distance between the light transflective layer and the light reflecting layer in the blue subpixel is a distance at which red light (R light), green light (G light), and blue light (B light) resonate.
Preferably, the optical distance between the light transflective layer and the light reflective layer in the white subpixel is the optical distance between the light transflective layer and the light reflective layer in the at least two types of subpixels. 2 times longer than the longest optical distance.
Preferably, the optical distance between the light transflective layer and the light reflective layer in the white subpixel is 2.0 μm or more. More preferably, it is 3.0 micrometers or more, More preferably, it is 4.0 micrometers or more.
Preferably, an optical path length adjusting layer is provided between the light transflective reflective layer and the light reflective layer, and at least two types of subpixels and white subpixels have a white organic electroluminescent layer having the same composition, and the optical path The thickness of the length adjusting layer is made different.

The display device of the present invention preferably includes a TFT for driving each subpixel in each subpixel portion. Preferably, the substrate of the display device of the present invention uses a TFT substrate as a substrate, and at least one of the sub-pixels has a planarization film on the substrate, and a light reflection layer on the planarization film. Have Further thereon, an optical path length adjusting layer, a white organic electroluminescent layer, and a light transflective layer are provided.
In another preferred embodiment, the light reflecting layer is provided between the planarizing film and the substrate or in the planarizing film. In this case, at least a part of the planarization layer functions as an optical path length adjustment layer.
A preferred specific embodiment is that a red subpixel, a green subpixel, a blue subpixel, and a white subpixel are formed on a planarizing film by a light reflecting layer, a light semi-transmissive reflective layer, and a light semi-transmissive reflective layer and a light reflective layer. And an optical path length adjusting layer and a white light emitting organic electroluminescent layer sandwiched therebetween.
In another preferred embodiment, the red sub-pixel, the green sub-pixel, and the blue sub-pixel are sandwiched between the light reflecting layer, the light semi-transmissive reflecting layer, and the light semi-transmissive reflecting layer and the light reflecting layer on the planarizing film. The white sub-pixel has a light reflection layer between the substrate and the planarizing film, and the transparent electrode and the white light-emitting organic layer are disposed on the planarizing film. It has an electroluminescent layer and a light transflective layer.

Preferably, the light reflecting layer of the white subpixel is formed of a layer common to the electrode of the TFT.
Preferably, a red color filter, a green color filter, and a blue color filter are disposed on the light emission side of the red light emission subpixel, the green light emission subpixel, and the blue light emission subpixel, respectively.

  In the present invention, it may be a top emission type organic EL or a bottom emission type organic EL element.

Next, the structure of the display device of the present invention will be specifically described with reference to the drawings.
FIG. 3 is a schematic cross-sectional view showing the configuration of R, G, B subpixels and W subpixels constituting one pixel according to the present invention.
On the substrate 1 on which the TFT is disposed, a planarizing film 6 is installed so as to cover the TFT. A light reflecting layer 2 is provided on the planarizing film. When insulation with the pixel electrode (transparent electrode 3) is maintained, the light reflecting layer may be provided in common for the R, G, B, and W subpixels.

Next, optical path length adjustment layers are installed with different thicknesses for each of the R, G, B, and W sub-pixels (optical path length adjustment layers 8-1, 8-2, 8-3, and 8-4, respectively). If the optical path length adjusting layer 8-1 of the B sub-pixel portion is the thinnest and has a thickness of 0, that is, the B pixel portion can provide a resonance distance, the optical path length adjusting layer may not be provided. It becomes thicker as it becomes the G subpixel portion and the R subpixel portion. The optical path length adjustment layer 8-4 of the W subpixel is the thickest, preferably thicker than the optical path length adjustment layer 8-3 of the R subpixel part, more preferably the optical path length adjustment layer 8 of the R subpixel part. It is more than twice the thickness of -3. The optical path length adjusting layer is preferably electrically insulating.
On the optical path length adjusting layer, the transparent electrode 3 as a pixel electrode is patterned and installed for each pixel. The transparent electrode 3 is electrically connected to the TFT through a contact hole.
A non-light emitting area between the sub-pixel portions is covered with a bank 7 (insulating layer).

On top of that, the white organic electroluminescent layer 4 and the transflective electrode 5 are installed in common with each sub-pixel. The white organic electroluminescent layer 4 is preferably a laminate of a plurality of functional layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer. The transflective electrode 5 may be a metal thin film (Al, Ag, etc.) or a distributed Bragg reflective film (DBR) in which transparent thin films having different refractive indexes are laminated. The optical path length adjusting layer is made of an insulating layer material, and may be any of inorganic substances (SiO ₂ , SiON, SiN, etc.) and organic substances (polycarbonate, polyacrylate, silicone resin, etc.).

  In each R, G, B subpixel, the thickness of the optical path length adjustment layer is adjusted so that the emitted light has a resonance distance. For example, an optical element that generates optical resonance between R (λ = 625 nm to 740 nm), G (λ = 500 nm to 565 nm), and B (λ = 450 nm to 485 nm) between the reflective layer 2 and the transflective electrode 5. A film thickness having a target distance L is formed. For example, for the B pixel portion, if the resonant optical distance is 380 nm, light having a maximum wavelength at 465 nm shown in FIG. 6 is extracted to the outside. When the resonance optical distance is set to 440 nm for the G pixel portion, light having a maximum wavelength at 526 nm shown in FIG. 7 is extracted to the outside. Assuming that the resonance optical distance of the R pixel portion is 520 nm, light having a maximum wavelength at 623 nm shown in FIG. 8 is extracted to the outside.

On the other hand, for the W pixel portion, the optical path length adjusting layer is adjusted to a thickness that is longer than the R pixel portion and does not emit light of a specific wavelength in the visible region. For example, when the resonant optical distance is 2.0 μm, as shown in FIG. 9, light of a resonant wave having a large number of emission peaks in the visible range is extracted to the outside. Therefore, the light of the W sub-pixel observed outside is almost white light in which they are mixed.
The light emitted from the white organic electroluminescent layer 4 by energization is repeatedly reflected and resonated between the semi-transmissive reflective electrode 5 and the light reflective layer 2, and R, G, and B light are respectively transmitted through the semi-transmissive reflective electrode. 5 is injected to the outside. In the W pixel portion, R, G, and B resonated light are mixed and observed as white light.

FIG. 4 is a schematic cross-sectional view showing the configuration of one pixel according to another aspect of the present invention.
The configuration of the R, G, and B sub-pixel portions is the same as that shown in FIG. In the W subpixel, on the substrate 11 on which the TFT is disposed, first, a reflective layer 12-2 is provided in a region where the W subpixel is installed. On top of this, a planarizing film 16 is provided so as to cover the TFT and the reflective layer 12-2. The planarizing film is disposed in common with the planarizing film 16 in the R, G, B subpixel portion. In the W sub-pixel portion, the planarizing film 16 functions as an optical path length adjustment layer. However, the thickness of the optical path length adjustment layer in the W sub-pixel may be thicker than a predetermined thickness, so the thickness is strictly controlled. There is no need. Therefore, sufficiently satisfactory performance can be obtained even by a general manufacturing method of the planarizing film.

Next, the transparent electrode 13 is provided as a pixel electrode on the planarizing film 16 in a pattern for each subpixel. The transparent electrode 13 is electrically connected to the TFT through a contact hole.
A non-light emitting region between the sub-pixel portions is covered with a bank 17 (insulating layer).
On top of this, the white organic electroluminescent layer 14 and the transflective electrode 15 are installed in common with each subpixel.
In order to further increase the optical distance between the reflective layer 12-2 and the semi-reflective transmissive layer 15 in the W pixel portion, an optical path length adjusting layer may be provided between the planarizing film 16 and the transparent electrode 13. .

FIG. 5 is a schematic cross-sectional view showing the configuration of one pixel according to still another aspect of the present invention.
The configuration of the W sub-pixel unit is the same as that shown in FIG.
In the R, G, and B sub-pixel portions, the light reflection layers are respectively disposed inside the planarization layer. In the B pixel portion, the light reflecting layer 22-1 is disposed on the uppermost portion of the planarizing layer 26. The light reflecting layers 22-2 and 22-3 of the G sub-pixel portion and the R sub-pixel portion are disposed in the flattening layer 26 at positions where the resonance distances are sequentially increased.
On the planarizing film 26, a transparent electrode 23 patterned in each R, G, B, W subpixel is formed.
A white organic electroluminescent layer 24 and a transflective electrode 25 are formed on each of the R, G, B, and W subpixels.

Therefore, according to the present invention, the light emitted from each of the R, G, and B subpixels is high-saturation light with high brightness and narrow spectral distribution, and extremely high-brightness and high-saturation light can be obtained. In addition, since the light emitted from the W pixel unit is not limited to a limited number of resonance lights having a specific wavelength, but is white light obtained by mixing a large number of resonance lights, the conventional W pixel unit has a resonator. And high brightness white light can be obtained.
In addition, since the organic electroluminescent layer and the transflective electrode of the R, G, B, and W subpixels can be formed in common and consistently, high definition is easy, the manufacturing process is simple, and high productivity is achieved. can get.

2. Optical path length adjusting layer The optical path length adjusting layer of the present invention is not particularly limited as long as it is a transparent insulating layer material, and any of inorganic substances (SiO ₂ , SiON, SiN, etc.) and organic substances (polycarbonate, polyacrylate, silicone resin, etc.) But it ’s okay.
As the inorganic insulating material used for the optical path length adjusting layer of the present invention, conventionally known various metal oxides, metal nitrides, metal fluorides and the like can be used.
Specific examples of the metal _{oxides, MgO, SiO, SiO 2,} Al 2 O 3, GeO, NiO, CaO, BaO, Fe 2 O 3, Y 2 O 3, TiO 2 and the like, metal nitrides Specific examples include SiN _x , SiN _x O _{y and the} like, and specific examples of the metal fluoride include MgF ₂ , LiF, AlF ₃ , CaF _{2 and the} like. Moreover, these mixtures may be sufficient.

  As the material of the optical path length adjusting layer of the present invention, an organic compound can also be used, and a film-forming polymer is preferably used. Examples of the film-forming polymer include polycarbonate, polyacrylate, silicone resin, polyvinyl butyral, and the like.

  The thickness of the optical path length adjusting layer is adjusted so that each subpixel has an optical distance at which light of a predetermined wavelength can resonate efficiently. Therefore, the optical distance to resonate is determined by the refractive index of the material sandwiched between the reflective film and the semi-transmissive reflective film, its composition, and thickness, and therefore is not determined by the optical path length adjusting layer. . Considering the configuration of a generally used organic EL light emitting layer, the thickness of the optical path length adjusting layer of each R, G, B sub-pixel part is a physical thickness, preferably 0 nm to 1000 nm, more preferably 20 nm to 500 nm, More preferably, it is 30 nm-200 nm.

  The method for forming the optical path length adjusting layer is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (High frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, or transfer method can be applied.

3. Organic electroluminescent layer The organic electroluminescent layer in the present invention is a conventionally known organic compound layer such as a hole transport layer, an electron transport layer, a block layer, an electron injection layer, and a hole injection layer in addition to the light emitting layer. You may have.

Details will be described below.
1) Layer structure <Electrode>
In the present invention, at least one of the pair of electrodes of the organic electroluminescent layer is a transparent electrode, and the other is a back electrode. The back electrode may be transparent or non-transparent.
<Configuration of organic compound layer>
There is no restriction | limiting in particular as a layer structure of the said organic compound layer, Although it can select suitably according to the use and objective of an organic electroluminescent element, It is formed on the said transparent electrode or the said back electrode. preferable. In this case, the organic compound layer is formed on the front surface or one surface on the transparent electrode or the back electrode.
There is no restriction | limiting in particular about the shape of a organic compound layer, a magnitude | size, thickness, etc., According to the objective, it can select suitably.

Specific examples of the layer configuration include the following, but the present invention is not limited to these configurations.
Anode / hole transport layer / light emitting layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode.

Each layer will be described in detail below.
2) Hole transport layer The hole transport layer used in the present invention contains a hole transport material. The hole transport material is not particularly limited as long as it has either a function of transporting holes or a function of blocking electrons injected from the cathode. As the hole transport material used in the present invention, any of a low molecular hole transport material and a polymer hole transport material can be used.
Specific examples of the hole transport material used in the present invention include the following materials.

Carbazole derivative, imidazole derivative, polyarylalkane derivative, pyrazoline derivative, pyrazolone derivative, phenylenediamine derivative, arylamine derivative, amino-substituted chalcone derivative, styrylanthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative, silazane derivative, aromatic third Conductive polymer oligomers such as amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers and polythiophenes, polythiophene derivatives , Polymer compounds such as polyphenylene derivatives, polyphenylene vinylene derivatives, and polyfluorene derivatives.
These may be used alone or in combination of two or more.

  The thickness of the hole transport layer is preferably 1 nm to 200 nm, and more preferably 5 nm to 100 nm.

3) Hole injection layer In the present invention, a hole injection layer can be provided between the hole transport layer and the anode.
The hole injection layer is a layer that facilitates injection of holes from the anode into the hole transport layer, and specifically, a material having a small ionization potential is preferably used among the hole transport materials. For example, a phthalocyanine compound, a porphyrin compound, a starburst type triarylamine compound, etc. can be mentioned, It can use suitably.
The thickness of the hole injection layer is preferably 1 nm to 300 nm.

4) Light emitting layer The light emitting layer used in the present invention contains at least one kind of light emitting material, and may contain a hole transport material, an electron transport material, and a host material as necessary.
The light emitting material used in the present invention is not particularly limited, and either a fluorescent light emitting material or a phosphorescent light emitting material can be used. A phosphorescent material is preferred from the viewpoint of luminous efficiency.
Moreover, a luminescent material may be used individually by 1 type, if white light emission is obtained, and may use 2 or more types together. The combination of the luminescent color of the luminescent material when two or more are used in combination is not particularly limited, but the blue luminescent material and the yellow luminescent material are used together, the blue luminescent material, the green luminescent material and the red luminescent material are used together, etc. Can be mentioned.

  Examples of the fluorescent light-emitting material include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxalates. Diazole derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, styrylamine derivatives, aromatic dimethylidene compounds, 8-quinolinol derivative metal complexes and rare earths Various metal complexes represented by complexes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, and poly Polymeric compounds such as fluorene derivatives. These can be used alone or in combination of two or more.

  Although it does not specifically limit as a phosphorescence-emitting material, An ortho metalated metal complex or a porphyrin metal complex is preferable.

  The ortho-metalated metal complex includes, for example, Akio Yamamoto, “Organic Metal Chemistry: Fundamentals and Applications”, pages 150 to 232; Yersin's “Photochemistry and Photophysics of Coordination Compounds”, pages 71-77, pages 135-146, Springer-Verlag (published in 1987), etc. The use of the orthometalated metal complex as a light emitting material in the light emitting layer is advantageous in terms of high luminance and excellent light emission efficiency.

  There are various ligands that form the ortho-metalated metal complex, which are also described in the above documents. Among them, preferred ligands include 2-phenylpyridine derivatives, 7,8- Examples include benzoquinoline derivatives, 2- (2-thienyl) pyridine derivatives, 2- (1-naphthyl) pyridine derivatives, and 2-phenylquinoline derivatives. These derivatives may have a substituent if necessary. The orthometalated metal complex may have other ligands in addition to the above ligands.

The orthometalated metal complex used in the present invention can be obtained from Inorg Chem. 1991, 30, 1685, 1988, 27, 3464, 1994, 33, 545, Inorg. Chim. Acta, 1991, No. 181, page 245; Organomet. Chem. 1987, No. 335, 293, J. Am. Am. Chem. Soc. It can be synthesized by various known techniques such as 1985, No. 107, page 1431.
Among the ortho-metalated complexes, compounds that emit light from triplet excitons can be suitably used in the present invention from the viewpoint of improving luminous efficiency.

Of the porphyrin metal complexes, a porphyrin platinum complex is preferred.
A phosphorescent material may be used alone or in combination of two or more. Further, a fluorescent material and a phosphorescent material may be used at the same time.

  The host material is a material having a function of causing energy transfer from the excited state to the fluorescent light-emitting material or the phosphorescent light-emitting material, and as a result, causing the fluorescent light-emitting material or the phosphorescent light-emitting material to emit light.

The host material is not particularly limited as long as it is a compound capable of transferring exciton energy to the light emitting material, and can be appropriately selected according to the purpose. Specifically, a carbazole derivative, a triazole derivative, an oxazole derivative, Oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic Tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopi Dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzothiazoles Various metal complexes represented by ligand metal complexes, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, polythiophene derivatives, polyphenylene derivatives , Polymer compounds such as polyphenylene vinylene derivatives and polyfluorene derivatives. These compounds may be used individually by 1 type, and may use 2 or more types together.
As content in the light emitting layer of a host material, 20 mass%-99.9 mass% are preferable, More preferably, they are 50 mass%-99.0 mass%.

5) Block layer In this invention, a block layer can be provided between a light emitting layer and an electron carrying layer. The block layer is a layer that suppresses the diffusion of excitons generated in the light emitting layer, and also a layer that suppresses holes from penetrating to the cathode side.

  The material used for the block layer is not particularly limited as long as it is a material that can receive electrons from the electron transport layer and pass the electrons to the light emitting layer, and a general electron transport material can be used. For example, the following materials can be mentioned. Triazole derivatives, oxazole derivatives, oxadiazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthaleneperylene, etc. Various metal complexes represented by metal tetracyclic anhydrides, metal complexes of phthalocyanine derivatives, 8-quinolinol derivatives, metal phthalocyanines, metal complexes having benzoxazole or benzothiazole as ligands, aniline copolymers, Polymers such as thiophene oligomers, conductive polymer oligomers such as polythiophene, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, and polyfluorene derivatives Mention may be made of the compound. These may be used individually by 1 type and may use 2 or more types together.

6) Electron transport layer In the present invention, an electron transport layer containing an electron transport material can be provided.
The electron transport material is not limited as long as it has either a function of transporting electrons or a function of blocking holes injected from the anode, and is mentioned when explaining the block layer. A suitable electron transport material can be used.
The thickness of the electron transport layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 80 nm.

  When the thickness exceeds 1000 nm, the driving voltage may increase. When the thickness is less than 10 nm, the light emission efficiency of the light emitting device may be extremely lowered, which is not preferable.

7) Electron Injection Layer In the present invention, an electron injection layer can be provided between the electron transport layer and the cathode.
The electron injection layer is a layer that facilitates injection of electrons from the cathode into the electron transport layer. Specifically, lithium salts such as lithium fluoride, lithium chloride, and lithium bromide, sodium fluoride, sodium chloride, fluoride An alkali metal salt such as cesium, an insulating metal oxide such as lithium oxide, aluminum oxide, indium oxide, or magnesium oxide can be suitably used.
The thickness of the electron injection layer is preferably 0.1 nm to 5 nm.

8) Substrate The material of the substrate used in the present invention is preferably a material that does not transmit moisture or a material with extremely low moisture permeability, and does not scatter or attenuate light emitted from the organic compound layer. Material is preferred. Specific examples include, for example, YSZ (zirconia stabilized yttrium), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, allyl diglycol carbonate, Examples thereof include organic materials such as polyimide, polycycloolefin, norbornene resin, and synthetic resin such as poly (chlorotrifluoroethylene).
In the case of the said organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, workability, low air permeability, or low hygroscopicity. These materials may be used alone or in combination of two or more.

  There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. Generally, the shape is a plate shape. The structure may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.

  The substrate may be colorless and transparent, or may be colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the light emitting layer.

The substrate is preferably provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface (on the transparent electrode side). As the material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
If necessary, the substrate may be further provided with a hard coat layer, an undercoat layer, and the like.

9) Electrode In the present invention, the first electrode and the second electrode may be either an anode or a cathode, but preferably the first electrode is an anode and the second electrode is a cathode. .

<Anode>
The anode used in the present invention is usually only required to have a function as an anode for supplying holes to the organic compound layer, and the shape, structure, size and the like are not particularly limited, and the light emitting device Depending on the use and purpose, it can be appropriately selected from known electrodes.

  As a material for the anode, for example, a metal, an alloy, a metal oxide, an organic conductive compound, or a mixture thereof can be preferably cited. A material having a work function of 4.0 eV or more is preferable. Specific examples include semiconducting metal oxides such as tin oxide (ATO, FTO) doped with antimony or fluorine, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO), etc. Metals such as gold, silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, organics such as polyaniline, polythiophene and polypyrrole Examples thereof include conductive materials and laminates of these with ITO.

  The anode may be, for example, a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, a chemical method such as a CVD method or a plasma CVD method, or the like. It can be formed on the substrate according to a method appropriately selected in consideration of suitability. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. Moreover, when selecting an organic electroconductive compound as a material of an anode, it can carry out according to the wet film forming method.

  There is no restriction | limiting in particular as a formation position in the said light emitting element of an anode, According to the use and purpose of this light emitting element, it can select suitably.

  The patterning of the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like, or may be performed by vacuum deposition or sputtering with a mask overlapped. Alternatively, it may be performed by a lift-off method or a printing method.

The thickness of the anode can be appropriately selected depending on the material and cannot be generally defined, but is usually 10 nm to 50 μm, and preferably 50 nm to 20 μm.
The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less.
The anode may be colorless and transparent or colored and transparent. In order to extract light emitted from the anode side, the transmittance is preferably 60% or more, and more preferably 70% or more. This transmittance can be measured according to a known method using a spectrophotometer.

  The anode is described in detail in Yutaka Sawada's “New Development of Transparent Electrode Film” published by CMC (1999), and these can be applied to the present invention. When using a plastic substrate having low heat resistance, an anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

<Cathode>
The cathode that can be used in the present invention is usually only required to have a function as a cathode for injecting electrons into the organic compound layer, and there is no particular limitation on the shape, structure, size, etc. According to the use and purpose of the element, it can be appropriately selected from known electrodes.

  Examples of the material for the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof, and those having a work function of 4.5 eV or less are preferable. Specific examples include alkali metals (for example, Li, Na, K, or Cs), alkaline earth metals (for example, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, Examples thereof include magnesium-silver alloys, rare earth metals such as indium and ytterbium. These may be used alone, but from the viewpoint of achieving both stability and electron injection properties, two or more of them can be suitably used in combination.

  Among these, alkali metals and alkaline earth metals are preferable from the viewpoint of electron injection properties, and materials mainly composed of aluminum are preferable from the viewpoint of excellent storage stability. The material mainly composed of aluminum is aluminum alone, or an alloy or mixture of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc. ).

  The cathode materials are described in detail in JP-A-2-15595 and JP-A-5-121172, and these can be applied to the present invention.

There is no restriction | limiting in particular in the formation method of a cathode, It can carry out according to a well-known method. For example, suitability with the above materials from among wet methods such as printing methods, coating methods, physical methods such as vacuum deposition methods, sputtering methods and ion plating methods, chemical methods such as CVD and plasma CVD methods, etc. It can be formed on the substrate according to a method appropriately selected in consideration.
For example, when a metal or the like is selected as the material of the cathode, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

  The patterning of the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or may be performed by vacuum deposition or sputtering with a mask overlapped. Alternatively, the lift-off method or the printing method may be used.

There is no restriction | limiting in particular as a formation position in the organic electroluminescent element of a cathode, Although it can select suitably according to the use and objective of this light emitting element, forming in an organic compound layer is preferable. In this case, the cathode may be formed on the entire organic compound layer or a part thereof.
Further, a dielectric layer made of the alkali metal or the alkaline earth metal fluoride may be inserted between the cathode and the organic compound layer with a thickness of 0.1 nm to 5 nm.

The thickness of the cathode can be appropriately selected depending on the material and cannot be generally specified, but is usually 10 nm to 5 μm, and preferably 20 nm to 500 nm.
The cathode may be transparent or opaque. The transparent cathode can be formed by forming the cathode material into a thin film with a thickness of 1 nm to 10 nm and further laminating the transparent conductive material such as ITO or IZO.

10) Protective layer In this invention, the whole organic EL element may be protected by the protective layer.
As a material contained in the protective layer, any material may be used as long as it has a function of preventing materials that promote device deterioration such as moisture and oxygen from entering the device.
Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, and Fe ₂ O. ₃ , metal oxides such as Y ₂ O ₃ , TiO ₂ , metal nitrides such as SiN _x , SiN _x O _y , metal fluorides such as MgF ₂ , LiF, AlF ₃ , CaF ₂ , polyethylene, polypropylene, polymethyl Monomer mixture containing methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer Copolymer obtained by copolymerization, cyclic in the copolymer main chain Examples thereof include a fluorine-containing copolymer having a structure, a water-absorbing substance having a water absorption of 1% or more, and a moisture-proof substance having a water absorption of 0.1% or less.

  The method for forming the protective layer is not particularly limited, and for example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, or transfer method can be applied.

11) Sealing Furthermore, the organic electroluminescent element in this invention may seal the whole element using a sealing container.
Further, a moisture absorbent or an inert liquid may be sealed in a space between the sealing container and the light emitting element.
Although it does not specifically limit as a moisture absorber, For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like. The inert liquid is not particularly limited, and examples thereof include paraffins, liquid paraffins, fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether, chlorinated solvents, and silicone oils. Can be mentioned.

12) Element manufacturing method Each layer constituting the element in the present invention is formed by a dry film forming method such as vapor deposition or sputtering, dipping, spin coating, dip coating, casting, die coating, roll coating, or bar coating. The film can be suitably formed by any of the wet film forming methods such as the method and the gravure coating method.
Of these, the dry method is preferred from the viewpoint of luminous efficiency and durability. In the case of the wet film forming method, the remaining coating solvent is not preferable because the light emitting layer is damaged.
Particularly preferred is a resistance heating vacuum deposition method. The resistance heating type vacuum vapor deposition method is advantageous because it can efficiently heat only the substance to be evaporated by heating under vacuum, and the element is not exposed to high temperature, and is therefore less damaged.

  Vacuum deposition is a method in which a deposition material is heated, vaporized or sublimated in a vacuumed container, and is attached to the surface of an object to be deposited placed at a slightly separated position to form a thin film. Heating is performed by a method such as resistance heating, electron beam, high-frequency induction, or laser depending on the type of vapor deposition material or deposition target. Of these, film formation at the lowest temperature is a resistance heating type vacuum vapor deposition method, and a material with a high sublimation point cannot be formed, but a material with a low sublimation point causes thermal damage to the material to be deposited. Film formation can be performed in almost no state.

The sealing film material in the present invention can be formed by resistance heating type vacuum deposition.
Conventionally used sealing agents such as silicon oxide have a high sublimation point and cannot be deposited by resistance heating. In addition, the vacuum deposition method such as ion plating generally described in known examples has an evaporation source part of several thousand degrees Celsius, so the material to be deposited is thermally affected and altered. Therefore, it is not suitable as a method for producing a sealing film of an organic EL element that is particularly susceptible to heat and ultraviolet rays.

13) Driving method The organic electroluminescent element in the present invention applies a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Thus, light emission can be obtained.

  The driving method of the organic electroluminescence device in the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234585, and JP-A-8-2441047. The driving methods described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429, 6023308, and the like can be applied.

(application)
The display device of the present invention is applied in a wide range of fields including mobile phone displays, personal digital assistants (PDAs), computer displays, automobile information displays, TV monitors, or general lighting.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
A method of manufacturing the color display device having the configuration shown in FIG. 3 according to the present invention will be described.
(1) A planarizing film 6 having a thickness of 3 μm is provided on a glass substrate 1 having TFTs so as to cover the TFTs. The TFTs are respectively installed corresponding to the R, G, B, and W subpixels.
(2) On the planarizing film 6, Al is deposited as a light reflecting layer 2 by patterning on each R, G, B, and W subpixels to a thickness of 100 nm by a vacuum film forming method.

(3) On the upper surface of the light reflecting layer 2, optical path length adjusting layers 8-1, 8-2, 8-3, 8 made of transparent insulating materials having different thicknesses at the respective R, G, B, W subpixel positions. -4 is formed.
・ Material: SiON
-Film formation method: ion plating method-Thickness: R part 120 nm, G part 70 nm, B part 30 nm, W part 2200 nm,
(4) A transparent electrode 3 (ITO, 60 nm) is formed on the upper surface of the optical path length adjusting layer by patterning with each sub-pixel. The transparent electrode 3 is electrically connected to the upper electrode of the planarization film of the TFT through contact holes provided in the optical path length adjusting layer and the reflective layer.
(5) The light emitting part is covered with a metal mask, and the non-light emitting part is covered with an insulating layer (bank 7).

(6) On the upper surface of the transparent electrode 3, the white light emitting electroluminescent layer 4 and the transflective electrode 5 are formed in the following order by vacuum deposition in common for the R, G, B, W subpixels.
<Light emitting layer configuration>
Hole injection layer: 4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine (abbreviated as 2-TNATA) and 2-TNATA and tetrafluorotetracyanoquinodimethane (F4) (Abbreviated as -TCNQ) was co-evaporated to 1.0 mass%. The film thickness was 40 nm.
Hole transport layer: N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviated as α-NPD), thickness 10 nm.
Luminescent layer: 15% by mass of luminescent material A, 0.13% by mass of luminescent material B, and 0% of luminescent material C with respect to 1,3-bis (carbazol-9-yl) benzene (abbreviated as mCP) and mCP Co-deposition was performed in four elements so as to be 13% by mass. The film thickness was 30 nm.
Electron transport layer: bis- (2-methyl-8-quinolinolate) -4- (phenylphenolate) aluminum (abbreviated as BAlq), thickness 40 nm.
Electron injection layer: LiF was deposited to a thickness of 0.5 nm, and then Al was deposited to a thickness of 1.5 nm to form an electron injection layer.

<Transflective electrode 5>
A metal electrode (Ag, 20 nm) is formed by a vacuum film forming method.

  The structures of the compounds used in the examples are shown below.

The obtained organic electroluminescent layer formation region is sealed, and each electrode is connected to an external signal control device.
As described above, one pixel incorporating a top emission type organic EL element is formed.

  A display surface is formed by arranging a plurality of pixels including the R, G, B, and W subpixels, and an image is formed on the display surface by selectively emitting light from each subpixel.

The light emitted from the organic electroluminescent layer 4 by energization resonates between the semi-transmissive reflective electrode 5 and the light reflective layer 2, and R, G, B light passes through the semi-transmissive reflective electrode 5. It is injected outside.
The B sub-pixel portion emits high-intensity B light with a sharp emission spectrum shown in FIG. 6, and the G sub-pixel portion emits high-intensity G light with a sharp emission spectrum shown in FIG. High-luminance R light having a sharp emission spectrum shown in FIG. 8 is emitted from the R sub-pixel portion.
In the W sub-pixel portion, a large number of resonance lights shown in FIG. 9 are mixed and light that is observed as completely white light is emitted.

  According to the above manufacturing method, the R, G, B, and W sub-pixels are made of the same material, except that the thickness of the optical path length adjusting layer is different. In particular, since the organic electroluminescent layer and the transflective electrode are common and can be formed consistently, there is no need to form each subpixel separately, which simplifies the manufacturing process, increases productivity, and increases the definition. It becomes easy.

Example 2
In the configuration shown in FIG. 4, only the configuration of the W sub-pixel unit in Example 1 was changed to the following. The manufacturing means of each configuration is the same as in the first embodiment.
(1) First, the light reflection layer 12-2 is placed on the TFT substrate 11.
(2) The flattening film 16 is provided so as to cover the TFT and the light reflection layer 12-2. The installation process of the flattening film 16 is performed in the same process as the installation of the flattening film 16 in the R, G, and B sub-pixel portions.
(3) Subsequent steps of laminating and forming the transparent electrode 13 / white organic electroluminescent layer 14 / semi-transmissive reflective electrode 15 are performed in the same step as in the R, G, B subpixel portion.

  In the configuration obtained above, the planarizing film 16 serves as the optical path length adjustment layer of the W sub-pixel portion. Compared to the first embodiment, since it is not necessary to provide a thick optical path length adjusting layer in the W sub-pixel portion, the manufacturing is further facilitated, and the W sub-pixel is more than that in the R, G, B sub-pixel portion. This is preferable because the portion is not particularly thick and the unevenness of the entire pixel is reduced and flattened.

Example 3
In the configuration shown in FIG. 5, the R, G, and B sub-pixel portions are also configured in such a manner that the light reflecting layer is arranged in the planarizing film with respect to the second embodiment.
(1) On the TFT substrate 21, first, the light reflecting layer 22-4 is installed with the W subpixel.
(2) A flattened film having a first thickness is provided through the R, G, B, and W sub-pixel portions so as to cover the TFT and the light reflecting layer 22-2.
(3) Next, the light reflection layer 22-3 is installed in the R subpixel.
(4) Subsequently, a flattening film having a second thickness is provided throughout the R, G, B, and W sub-pixel portions.
(5) Next, the light reflection layer 22-2 is installed in the G subpixel.
(6) Subsequently, a flattening film having a third thickness is provided throughout the R, G, B, and W sub-pixel portions.
(7) Next, in the B subpixel, the light reflecting layer 22-1 is installed.
(8) Subsequently, a flattened film having a fourth thickness is provided throughout the R, G, B, and W sub-pixel portions.
(9) The subsequent steps of laminating and forming the transparent electrode 23 / white organic electroluminescent layer 24 / semi-transmissive reflective electrode 25 are common to the R, G, B, and W sub-pixels as in Examples 1 and 2. The same is done.

  In the configuration obtained above, the optical path length adjustment layers of all the sub-pixel portions are installed in the planarization film. Therefore, since it is not necessary to provide an optical path length adjusting layer outside the planarizing film, the R, G, B, and W sub-pixel portions are all formed with the same thickness. preferable. Furthermore, the transparent electrode, the white organic electroluminescent layer, and the transflective electrode can be formed of the same material and in the same process, so that the manufacturing process is simplified and high definition is easy.

1, 11, 21: Substrate 2, 12-1, 12-2, 22-1, 22-2, 22-3, 22-4: Light reflecting layer 3, 13, 23: Transparent electrode 4, 14, 24: White organic electroluminescent layer 5, 15, 25: Transflective electrode 6, 16, 26: Flattened film 7, 17, 27: Insulating layer (bank)
8-1, 8-2, 8-3, 8-4, 18-1, 18-2, 18-3: Optical path length adjusting layer (insulating layer)

Claims (1)

  A color display device comprising a plurality of pixels on a substrate, each pixel including at least two types of sub-pixels and white sub-pixels that emit light having different wavelengths in the visible range, wherein the at least two types of sub-pixels And the white sub-pixels each include a white light-emitting organic electroluminescent layer sandwiched between a light semi-transmissive reflective layer and a light reflective layer, and the light semi-transmissive reflective layer and the light reflective layer in the at least two types of sub-pixels. The optical distance between the layers forms a resonator that resonates the emitted light, and the optical distance between the light transflective layer and the light reflective layer in the white subpixel is: The color display device, wherein the optical distance between the light transflective layer and the light reflective layer in the at least two types of sub-pixels is longer than a longest optical distance.