JP2019096428A - Display device - Google Patents

Abstract

To provide an organic EL display device of which the luminance is kept over a range of a wide angle of view and which reduces a color change over the range of the wide angle of view.SOLUTION: A light-emitting element includes: a first electrode; a light-emitting layer which is provided on the first electrode; multiple layers which are provided between the first electrode and the light-emitting layer; and a second electrode which is provided on the light-emitting layer. In the light-emitting element, when the number of the multiple layers is defined as (k), an index of refraction of each of the multiple layers is defined as ni, film thickness of each of the layers is defined as di, a wavelength of a light in a color emitted by the light-emitting element is defined as λ, a length resulting from adding a phase shift due to interface reflection in each of the layers and an offset length is defined as (a), (i) is defined as a natural number from 1 to (k) and a degree (m) is an integer equal to or greater than 0, it leads a formula shown in the figure. The light-emitting element includes a first light-emitting element which emits a light in red, a second light-emitting element which emits a light in green, and a third light-emitting element which emits a light in blue. AT least one of the degree (m) in the first light-emitting element and the degree (m) in the second light-emitting element is greater than the degree (m) in the third light-emitting element.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an organic EL display device.

  An organic electroluminescence display is known as one of display devices. The organic EL display device uses an organic electroluminescent material (organic EL material) for a light emitting element (organic EL element) of a display portion. Unlike a liquid crystal display device or the like, the organic EL display device is a so-called self-luminous display device which realizes display by causing an organic EL material to emit light.

  For example, in a top emission type organic EL display device, a microcavity structure is generally adopted that utilizes the light resonance effect between a reflective electrode as a pixel electrode and a semitransparent electrode as a counter electrode. . In the microcavity structure, the pixel electrodes and the counter electrode are arranged so that the EL spectrum peak wavelength of each color of red, green and blue is matched with the optical path length between the pixel electrode and the counter electrode, and the strongest light can be extracted from each color. Change the thickness of the organic layer between In the organic EL display device, for example, the organic EL elements of each color of red (R), green (G), and blue (B) are made to emit light, and white light is synthesized when it is synthesized. The problem is that the color change is small in a wide range of viewing angles. In the white light emission of the organic EL display device, in order to maintain the luminance in a wide range of viewing angle and to suppress the color change in a wide range of viewing angle, generally, the blue light emission luminance viewing angle is red light emission It is said that it is preferable to be broad for green light emission.

  For example, in Patent Document 1, in order to improve element characteristics, in the red light emitting element, the film thickness of the organic layer between the pixel electrode and the counter electrode is made constant, and the optical path between the pixel electrode and the counter electrode is made. It is disclosed to adjust the length to be a natural number multiple (order multiple) of the red wavelength.

JP, 2009-217948, A

  Since the optical path length between the pixel electrode and the counter electrode is adjusted to be a natural number multiple (order multiple) of the wavelength of the color emitted by the light emitting element, the light emitting element The directivity of the color to be emitted becomes stronger. Therefore, it may be difficult to maintain brightness in a wide range of viewing angle and to suppress color change in a wide range of viewing angle in white emission when light emitting and combining organic EL materials of respective colors is used. is there.

  In view of the above problems, it is an object of the present invention to provide an organic EL display device in which the luminance is maintained in a wide range of viewing angle and the color change is small in a wide range of viewing angle.

であって、発光素子は、赤色で発光する第１発光素子と、緑色で発光する第２発光素子と、青色で発光する第３発光素子と、を含み、第１発光素子における次数ｍと第２発光素子における次数ｍの少なくとも一方は、第３発光素子における次数ｍよりも大きい。 A display device according to an embodiment of the present invention includes a display portion provided with a light emitting element, and the light emitting element includes a first electrode electrically connected to a transistor, and light emission provided on the first electrode. Layer, a plurality of layers provided between the first electrode and the light emitting layer, and a second electrode provided on the light emitting layer, the number of the plurality of layers being k, each layer of the plurality of layers being The refractive index is ni, the film thickness of each layer is di, the wavelength of the light of the color emitted by the light emitting element is λ, and the sum of the phase shift due to interface reflection of each layer and the offset length is a, i from 1 When natural numbers up to k and order m are integers of 0 or more,

The light emitting element includes a first light emitting element that emits red light, a second light emitting element that emits green light, and a third light emitting element that emits blue light, the order m and the first light emitting element of the first light emitting element At least one of the orders m in the two light emitting elements is larger than the order m in the third light emitting element.

  A display device according to an embodiment of the present invention includes a display portion provided with a light emitting element, and the light emitting element includes a first electrode electrically connected to a transistor, and light emission provided on the first electrode. Layer, a plurality of layers provided between the first electrode and the light emitting layer, and a second electrode provided on the light emitting layer, wherein the light emitting element is a first light emitting element that emits red light, and a green color And a third light emitting element emitting blue light, wherein the number of the plurality of layers is k, the film thickness of each layer of the plurality of layers is di, and i is 1 to k When natural numbers are used, に お け る di in the first light emitting element is 150 nm or more larger than に お け る di in the third light emitting element, and Σdi in the first light emitting element is a distance that enhances the red light emitted by the first light emitting element. And, Σdi in the third light emitting element causes the third light emitting element to emit light That is the distance to enhance the blue light.

  A display portion provided with a light emitting element is provided, and the light emitting element includes a first electrode electrically connected to the transistor, a light emitting layer provided on the first electrode, and a space between the first electrode and the light emitting layer. The light emitting element includes a first light emitting element emitting red light, a second light emitting element emitting green light, and a second light emitting element provided on the light emitting layer. And a third light emitting element, and the thickness of the organic layer in the first light emitting element is 150 nm or more larger than the thickness of the organic layer in the third light emitting element.

It is the schematic which showed the structure of the display apparatus which concerns on one Embodiment of this invention. FIG. 2 is a schematic view of a cross section taken along line A <b> 1-A <b> 2 of the display device shown in FIG. 1. It is sectional drawing explaining the manufacturing method of the display apparatus which concerns on one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the display apparatus which concerns on one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the display apparatus which concerns on one Embodiment of this invention. It is sectional drawing explaining the manufacturing method of the display apparatus which concerns on one Embodiment of this invention. It is the top view to which a part of display part of the display concerning one embodiment of the present invention was expanded. It is the top view to which a part of display part of the display concerning one embodiment of the present invention was expanded. It is the top view to which a part of display part of the display concerning one embodiment of the present invention was expanded. FIG. 2 is a schematic view of a cross section taken along line A <b> 1-A <b> 2 of the display device shown in FIG. 1. FIG. 2 is a schematic view of a cross section taken along line A <b> 1-A <b> 2 of the display device shown in FIG. 1. FIG. 2 is a schematic view of a cross section taken along line A <b> 1-A <b> 2 of the display device shown in FIG. 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. However, the present invention can be implemented in various modes without departing from the scope of the present invention, and the present invention is not construed as being limited to the description of the embodiments exemplified below. In addition, with respect to the drawings, the width, thickness, shape, etc. of each part may be schematically represented in comparison with the actual aspect in order to make the description clearer. It does not limit the interpretation of the invention. Furthermore, in the present specification and the like and the drawings, the same or similar elements as or to those described with reference to the drawings in the drawings may be denoted by the same reference numerals, and overlapping descriptions may be omitted.

  In the present invention, when one film is processed to form a plurality of films, the plurality of films may have different functions and roles. However, the plurality of films are derived from the film formed as the same layer in the same step, and have the same layer structure and the same material. Therefore, these multiple films are defined as existing in the same layer.

In the present specification and the like, expressions such as “upper” and “lower” at the time of describing the drawings express the relative positional relationship between the structure of interest and the other structures. In the present specification and the like, in a side view, the direction from the insulating surface described later toward the bank is defined as “upper”, and the opposite direction is defined as “lower”. In the present specification and claims, when expressing an aspect in which another structure is disposed on a certain structure, in the case where it is simply referred to as “on”, unless otherwise noted, a structure It includes both the case where another structure is arranged immediately above and the case where another structure is arranged above another structure via another structure.

  Note that the ordinal numbers such as “first”, “second”, and “third” in the present specification and the like are used merely for the sake of brevity and should not be interpreted restrictively.

1. BACKGROUND OF THE INVENTION The inventors of the present invention have made a display unit of a microcavity structure having a light emitting element, a plurality of optical path length adjusting films laminated on the light emitting element, and a sealing film laminated on a plurality of optical path length adjusting films. We are examining an organic EL display device that we have. A light emitting element of this organic EL display device includes an anode, an organic layer having a light emitting layer laminated on the anode, and a cathode (cathode) laminated on the organic layer. The light emitting element includes a first light emitting element that emits red light, a second light emitting element that emits green light, and a third light emitting element that emits blue light. For example, a hole injection layer (Hole Injection Layer), a hole transport layer (Hole Transfer Layer), and an electron blocking layer (Electron Blocking Layer) are included between the anode and the light emitting layer. For example, a hole blocking layer (Hole Blocking Layer), an electron injection layer (Electron Injection Layer), and an electron transport layer (Electron Transfer Layer) are included between the light emitting layer and the cathode. The details will be described in FIG. 2, but under the conditions in which light in the light interference strengthens each other, in other words, the component reflected by the anode of the light emitted from the light emitting layer and the other component different from the component The organic EL material of each color is made to emit light by setting at least one of the order m in the first light emitting element and the order m in the second light emitting element larger than the order m in the third light emitting element under the condition that It has been found that, in white light emission when combined, luminance can be maintained in a wide range of viewing angles, and color change can be suppressed in a wide range of viewing angles.

2. First Embodiment In the present embodiment, a display device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

2-1. Configuration of Display Device FIG. 1 is a schematic view showing a configuration of a display device 100 according to an embodiment of the present invention. Further, FIG. 1 shows a schematic configuration when the display device 100 is viewed in plan. In the present specification and the like, a state in which the display device 100 is viewed from the direction perpendicular to the screen (display unit) is referred to as “plan view”.

  The display device 100 includes a display portion 103 formed on an insulating surface, a scanning signal line drive circuit 104, and a driver IC 106. Further, an opposing substrate 102 is provided above the display portion 103 and the scanning signal line driver circuit 104. A plurality of scanning signal lines 105 are connected to the scanning signal line drive circuit 104. The plurality of scanning signal lines 105 are arranged in the x direction of the display device 100. The driver IC 106 functions as a control unit that supplies a signal to the scan signal line drive circuit 104. The driver IC 106 incorporates a video signal line drive circuit. Although not shown, a plurality of video signal lines are connected to the driver IC 106. The plurality of video signal lines are arranged in the y direction intersecting the x direction. Further, although the driver IC 106 is provided on the flexible printed substrate 108 by a COF (Chip on Film) method, the driver IC 106 may be provided on the first substrate 101. Flexible printed circuit board 108 is connected to terminal 107 provided in peripheral region 110.

  Here, the insulating surface is the surface of the first substrate 101. The first substrate 101 supports the layers provided on the surface of the first substrate 101, such as transistors and light emitting elements. As the first substrate 101, for example, a glass substrate, a semiconductor substrate, or the like can be used. Further, as the first substrate 101, a foldable substrate may be used. As the foldable substrate, for example, an organic resin material such as polyimide, acrylic, epoxy or polyethylene terephthalate can be used. The first substrate 101 may be a material that transmits light or a material that does not transmit light. Further, as the opposite substrate 102, a substrate similar to the first substrate 101 can be used.

  In the display unit 103, a plurality of pixels are arranged in a matrix so as to cross each other in a direction (for example, an x direction and ay direction intersecting each other). Each of the plurality of pixels includes any of a light emitting element emitting light in a first color, a light emitting element emitting light in a second color, and a light emitting element emitting light in a third color. In the present specification and the like, when the display device 100 includes light emitting elements of red (R), green (G), and blue (B), one pixel emits light of one of three colors. It refers to a region having elements. In addition, the color which a light emitting element emits light is not limited to three colors, Four or more colors may be sufficient. In FIG. 1, each of the plurality of red pixels 109R (pixels 109R), the plurality of green pixels 109G (pixels 109G), and the plurality of blue pixels 109B (pixels 109B) is one direction (y direction of the display portion 103). The case of the stripe arrangement, which is arranged along the.

  Each of the pixel 109R, the pixel 109G, and the pixel 109B includes a pixel electrode described later and a light emitting element. The light emitting element is composed of a part (anode) of the pixel electrode, an organic layer (light emitting part) including a light emitting layer laminated on the pixel electrode, and a cathode (cathode). In FIG. 1, portions shown as the pixel 109 R, the pixel 109 G, and the pixel 109 B are light emitting regions of the respective light emitting elements. FIG. 1 shows an example in which the area of the light emitting region of each pixel is substantially the same. However, the area of the light emitting area of each pixel may be different for each color.

  A data signal corresponding to image data is supplied to each of the pixel 109R, the pixel 109G, and the pixel 109B from a video signal line drive circuit incorporated in the driver IC 106. For example, a transistor electrically connected to a pixel electrode provided in the pixel 109R is driven according to a data signal corresponding to image data, whereby an image corresponding to the image data is displayed on the pixel 109R. Similarly to the pixel 109R, by driving the pixel 109G and the pixel 109B, the display device 100 can display an image according to the image data. Here, for example, a thin film transistor (TFT) can be used as the transistor. Note that an element that displays an image according to the image data in a pixel is not limited to a transistor, and any element may be used as long as it has an electric current control function.

  FIG. 2 is a schematic view of a cross section taken along line A1-A2 of the display device shown in FIG. Specifically, FIG. 2 shows a cross section of the light emitting element and the optical path length adjustment film in each of the pixel 109R, the pixel 109G, and the pixel 109B. The pixel 109R has a light emitting element 130R. The pixel 109G includes a light emitting element 130G. The pixel 109B includes a light emitting element 130B. The light emitting element 130R further includes an organic layer 127R. The light emitting element 130G includes an organic layer 127G. The light emitting element 130B includes an organic layer 127B.

  The structures of the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B will be described in detail. A pixel electrode 125a is provided for each of the pixel 109R, the pixel 109G, and the pixel 109B. That is, the pixel electrode 125a is provided for each pixel. The pixel electrode 125a is formed of a reflective material.

  The hole injection layer 161 is provided on the pixel electrode 125a. The hole injection layer 161 is commonly provided to the pixel 109R, the pixel 109G, and the pixel 109B.

  A hole transport layer is provided on the hole injection layer 161. The hole transport layer is formed in three parts. First, the hole transport layer 162a is provided commonly to the pixel 109R, the pixel 109G, and the pixel 109B. Second, the hole transport layer 162b is provided in the region where the pixel 109R is formed. Third, the hole transport layer 162c is provided in the region where the pixel 109G is formed. By forming the hole transport layer in three times, the thickness of the hole transport layer can be changed for each color of the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B. Therefore, the optical path length can be adjusted for each color of the light emitting element. Therefore, it is possible to resonate and emphasize only the light of the wavelength matching the optical path length, and weaken the light of the wavelength whose optical path length is shifted. Therefore, the spectrum of light extracted to the outside becomes high in intensity, and the luminance and the color purity are improved. The thickness of the hole transport layer of the pixel 109R is larger than the thickness of the hole transport layer of the pixel 109G and the thickness of the hole transport layer of the pixel 109B. The thickness of the hole transport layer of the pixel 109G is thicker than the thickness of the hole transport layer of the pixel 109B.

  An electron blocking layer 163 is provided on the hole transport layer. The electron blocking layer 163 is provided commonly to the pixel 109R, the pixel 109G, and the pixel 109B.

  A light emitting layer 164R, a light emitting layer 164G, and a light emitting layer 164B are provided on the electron blocking layer 163. The light emitting layer 164R is provided in the pixel 109R. The light emitting layer 164G is provided in the pixel 109G. The light emitting layer 164B is provided in the pixel 109B.

  The hole blocking layer 165 is commonly provided on the light emitting layer 164R, the light emitting layer 164G, and the light emitting layer 164B. The electron transport layer 166 is provided on the hole blocking layer 165. An electron injection layer 167 is provided on the electron transport layer 166. That is, the hole blocking layer 165, the electron transport layer 166, and the electron injection layer 167 are commonly provided to the pixel 109R, the pixel 109G, and the pixel 109B.

  The counter electrode 128 is provided on the electron injection layer 167. The counter electrode 128 is provided commonly to the pixels 109R, 109G, and 109B. The counter electrode 128 is formed of a conductive material having transparency.

  As described above, the organic layer 127R includes the hole injection layer 161, the hole transport layer 162a, the hole transport layer 162b, the electron blocking layer 163, the light emitting layer 164R, the hole blocking layer 165, the electron transport layer 166, and An electron injection layer 167 is provided. The organic layer 127G includes a hole injection layer 161, a hole transport layer 162a, a hole transport layer 162c, an electron blocking layer 163, a light emitting layer 164G, a hole blocking layer 165, an electron transport layer 166, and an electron injection layer 167. . The organic layer 127B includes a hole injection layer 161, a hole transport layer 162a, an electron blocking layer 163, a light emitting layer 164B, a hole blocking layer 165, an electron transport layer 166, and an electron injection layer 167.

  As described above, the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B can be formed by stacking the pixel electrode 125a to the counter electrode 128, respectively.

  As described above, in the light emitting element 130R, for example, the hole injection layer 161, the hole transport layer 162a, the hole transport layer 162b, and the electron blocking layer 163 are provided between the pixel electrode 125a and the light emitting layer 164R. Be In the light emitting element 130G, for example, a hole injection layer 161, a hole transport layer 162a, a hole transport layer 162c, and an electron blocking layer 163 are provided between the pixel electrode 125a and the light emitting layer 164G. In the light emitting element 130B, for example, a hole injection layer 161, a hole transport layer 162a, and an electron blocking layer 163 are provided between the pixel electrode 125a and the light emitting layer 164B.

  In the light emitting element 130R, the refractive index of the hole injection layer 161 is n1, the film thickness of the hole injection layer 161 is d1, the refractive index of the hole transport layer 162a is n2, the film thickness of the hole transport layer 162a is d2, and the positive The light of the color in which the refractive index of the hole transport layer 162b is n3, the thickness of the hole transport layer 162b is d3, the refractive index of the electron blocking layer 163 is n4, the thickness of the electron blocking layer 163 is d4, and the light emitting element 130R emits light. When the wavelength of λ is a wavelength of λR, the phase shift due to interface reflection of each layer and the offset length are aR, and the order mR is an integer of 0 or more, the condition under which light in light interference is enhanced is Equation 1 Indicated. The distance dR between the pixel electrode 125a and the light emitting layer 164R is dR = d1 + d2 + d3 + d4. The refractive index of each layer is, for example, 1.5 or more and 2.5 or less. Further, λR is preferably 600 nm or more and 680 nm or less.

  For example, in the light emitting element 130G, the refractive index of the hole injection layer 161 is n1, the film thickness of the hole injection layer 161 is d1, the refractive index of the hole transport layer 162a is n2, and the film thickness of the hole transport layer 162a is d2. The refractive index of the hole transport layer 162c is n5, the film thickness of the hole transport layer 162c is d5, the refractive index of the electron blocking layer 163 is n4, the film thickness of the electron blocking layer 163 is d4, and the color in which the light emitting element 130G emits light. If the wavelength of the light of this light is λG, the length obtained by adding the phase shift due to the interface reflection of each layer and the offset length is aG, and the order mG is an integer of 0 or more, the conditions for light in interference of light strengthen each other It is indicated by 2. The distance dG between the pixel electrode 125a and the light emitting layer 164G is dG = d1 + d2 + d5 + d4. The refractive index of each layer is, for example, 1.5 or more and 2.5 or less. Further, λG is preferably 500 nm or more and 560 nm or less.

  For example, in the light emitting element 130B, the refractive index of the hole injection layer 161 is n1, the film thickness of the hole injection layer 161 is d1, the refractive index of the hole transport layer 162a is n2, and the film thickness of the hole transport layer 162a is d2. The refractive index of the electron blocking layer 163 is n4, the film thickness of the electron blocking layer 163 is d4, the wavelength of light of the color emitted by the light emitting element 130B is λB, and the phase shift due to interface reflection of the layers and the offset length are added. Assuming that the length is aB and the order mB is an integer of 0 or more, the condition under which light in the light interference is enhanced is represented by Formula 3. The distance dB between the pixel electrode 125a and the light emitting layer 164B is dB = d1 + d2 + d4. The refractive index of each layer is, for example, 1.5 or more and 2.5 or less. Further, λB is preferably 430 nm or more and 500 nm or less.

  Similarly, in the light emitting device, the number of layers of the plurality of layers is i, the refractive index of each layer i of the plurality of layers is ni, the film thickness of each layer i of the plurality of layers is di, and the light emitting device emits light Let the wavelength of the light of the color to be added be λ, the length obtained by adding the phase shift due to the interface reflection of each layer and the offset length be a, i be a natural number, and m be an integer greater than 0. The condition is expressed by Equation 4.

  In one embodiment of the present invention, at least one of the order mR of the light emitting element 130R and the order mG of the light emitting element 130G is larger than the order mB of the light emitting element 130B. In the present specification, the light emitting element 130R may be referred to as a first light emitting element. The light emitting element 130G may be referred to as a second light emitting element. The light emitting element 130B may be referred to as a third light emitting element.

  The order mR of the light emitting element 130R is larger than the order mB of the light emitting element 130B, and the order mG of the light emitting element 130G and the order mB of the light emitting element 130B may be substantially the same.

  The distance dR (Σdi) between the pixel electrode 125a and the light emitting layer 164R in the light emitting element 130R may be 150 nm or more larger than the distance dB (Σdi) between the pixel electrode 125a and the light emitting layer 164B in the light emitting element 130B. . The distance dR (Σdi) between the pixel electrode 125a and the light emitting layer 164R in the light emitting element 130R is a distance that enhances the red light emitted by the light emitting element 130R, and dB (Σdi) in the light emitting element 130B is It is a distance that intensifies the blue light emitted by the light emitting element 130B.

  The distance dB (Σdi) between the pixel electrode 125a and the light emitting layer 164G in the light emitting element 130G may be larger by 120 nm or more than the distance dB (Σdi) between the pixel electrode 125a and the light emitting layer 164B in the light emitting element 130B. .

  An optical path length adjustment film is provided on the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B. The optical path length adjusting film 151 may have a role as a half mirror. When the optical path length adjusting film 151 has a role as a half mirror, the optical path length adjusting film 151 has a microcavity structure utilizing the resonance effect of light together with the reflective pixel electrode 125 a and the transparent counter electrode 128. Become a component of

  The optical path length adjustment film 151 is formed of, for example, a common organic material or a transparent conductive material such as ITO. The refractive index of the optical path length adjusting film 151 is preferably, for example, 1.6 to 2.6.

2-2. Method of Manufacturing Display Device FIGS. 3 to 6 are cross-sectional views for explaining a method of manufacturing a display device according to an embodiment of the present invention. 3 to 6 show cross sections of three pixels of the pixel 109R, the pixel 109G, and the pixel 109B included in the display unit 103.

  As shown in FIG. 3, the display device 100 includes a first substrate 101 and a second substrate 112. The first substrate 101 and the second substrate 112 are, for example, a glass substrate, a quartz substrate, or a flexible substrate (polyimide, polyethylene terephthalate, polyethylene naphthalate, triacetyl cellulose, cyclic olefin copolymer, cycloolefin polymer, other flexible Resin substrate) can be used. In the case where the first substrate 101 and the second substrate 112 do not need to have light transmitting properties, a metal substrate, a ceramic substrate, or a semiconductor substrate may be used. In the present embodiment, the first substrate 101 uses polyimide and the second substrate 112 uses polyethylene terephthalate.

  First, the base film 113 is formed on the first substrate 101. The base film 113 is an insulating layer. The material forming the base film 113 is, for example, an inorganic material such as silicon oxide, silicon nitride, or aluminum oxide. Although the base film 113 is formed in one layer in this embodiment, for example, the base film 113 may be formed by stacking a silicon oxide layer and a silicon nitride layer. The base film 113 may be appropriately determined in consideration of adhesion to the first substrate 101 and gas barrier properties to the transistor 120 described later.

  Next, the transistor 120 is formed over the base film 113. The structure of the transistor 120 may be top gate type or bottom gate type. In this embodiment, the transistor 120 includes the semiconductor layer 114 provided over the base film 113, the gate insulating film 115 covering the semiconductor layer 114, and the gate electrode 116 provided over the gate insulating film 115. In addition, an interlayer insulating layer 122 which covers the gate electrode 116 is formed over the transistor 120. Further, the source or drain electrode 117 and the source or drain electrode 118 are formed over the interlayer insulating layer 122. The source or drain electrode 117 and the source or drain electrode 118 are electrically connected to the semiconductor layer 114. Note that although the interlayer insulating layer 122 is formed of one layer in this embodiment, for example, two or more layers of the interlayer insulating layer 122 may be stacked.

  The materials of the layers included in the transistor 120 may be known materials and are not particularly limited. As a material for forming the semiconductor layer 114, for example, polysilicon, amorphous silicon, or an oxide semiconductor can be used. As a material for forming the gate insulating film 115, silicon oxide or silicon nitride can be used, for example. As a material for forming the gate electrode 116, for example, a metal material such as copper, molybdenum, tantalum, tungsten, or aluminum can be used. As a material for forming the interlayer insulating layer 122, silicon oxide or silicon nitride can be used, for example. As materials for forming the source or drain electrode 117 and the source or drain electrode 118, metal materials such as copper, titanium, molybdenum, or aluminum can be used.

  Although not shown, in the same layer as the gate electrode 116, a first wiring formed of the same metal material as the metal material for forming the gate electrode 116 can be provided. The first wiring is, for example, a scanning signal line driven by the scanning signal line drive circuit 104. Although not illustrated, a second wiring which extends in a direction intersecting with the first wiring can be provided in the same layer as the source or drain electrode 117 and the source or drain electrode 118. The second wiring is, for example, a video signal line driven by a video signal line drive circuit.

  Subsequently, a planarization film 123 is formed over the transistor 120. The planarization film 123 contains an organic resin material. A known organic resin material can be used as the organic resin material. For example, the organic resin material is polyimide, polyamide, acrylic, epoxy or the like. The planarization film 123 can reduce unevenness of the gate electrode 116, the source or drain electrode 117, and the source or drain electrode 118 which form the transistor 120, and the surface of the film can be substantially flat. The planarization film 123 is formed by, for example, a solution coating method. In the present embodiment, the planarization film 123 is formed as one layer, but for example, a layer containing an organic resin material and an inorganic insulating layer may be stacked.

  Subsequently, contact holes are formed in the planarizing film 123. The contact holes expose part of the source or drain electrode 118. The contact hole is an opening for electrically connecting a pixel electrode 125, which will be described later, and the source or drain electrode 118. Therefore, the contact hole is provided to overlap with part of the source or drain electrode 118. At the bottom of the contact hole, the source or drain electrode 118 is exposed.

  Subsequently, a protective film 124 is formed on the planarization film 123. The protective film 124 overlaps the contact hole formed in the planarization film 123. The protective film 124 preferably has a barrier function against moisture and oxygen. As a material for forming the protective film 124, an inorganic insulating material such as a silicon nitride film or aluminum oxide can be used, for example.

  Subsequently, the pixel electrode 125 is formed on the protective film 124. The pixel electrode 125 is electrically connected to the source or drain electrode 118 through a contact hole provided in the protective film 124 and the planarization film 123. In the display device 100 according to the present embodiment, the pixel electrode 125 functions as an anode that constitutes the light emitting element 130. The pixel electrode 125 has a different configuration depending on whether the display device 100 is a top emission type or a bottom emission type. For example, when the display device 100 is a top emission type, a metal material with high reflectance is used as a material for forming the pixel electrode 125. When the display device 100 is a top emission type, the material forming the pixel electrode 125 is an indium oxide based transparent conductive material (for example, Indium Tin Oxide (ITO)) or a zinc oxide based transparent conductive material (for example, A layered structure of a transparent conductive material with a high work function, such as Indium Zinc Oxide (IZO) or Zinc Oxide (ZnO), and a metal material can also be used. Further, for example, when the display device 100 is a bottom emission type, the material of the pixel electrode 125 uses the above-described transparent conductive material. In the present embodiment, a top emission type organic EL display device will be described as an example.

  The first insulating layer 126 is formed on the pixel electrode 125. As a material forming the first insulating layer 126, an organic resin material is used. As the organic resin material, for example, a known resin material such as polyimide, polyamide, acrylic, epoxy or siloxane can be used. The first insulating layer 126 has an opening on a part of the pixel electrode 125. The first insulating layer 126 is provided between the pixel electrodes 125 adjacent to each other so as to cover the end (edge) of the pixel electrode 125. Thus, the first insulating layer 126 functions as a member for separating the adjacent pixel electrodes 125. The first insulating layer 126 is generally called "partition wall" or "bank". A part of the pixel electrode 125 exposed from the first insulating layer 126 serves as a light emitting region of the light emitting element 130. The opening of the first insulating layer 126 preferably has a tapered inner wall. By forming the inner wall of the opening of the first insulating layer 126 in a tapered shape, coverage defects at the end of the pixel electrode 125 can be reduced when forming a light emitting layer to be described later. Further, the first insulating layer 126 may not only cover the end portion of the pixel electrode 125, but also may function as a filling material for filling a concave portion resulting from the contact hole included in the planarization film 123 and the protective film 124.

  An organic layer 127 is formed on the pixel electrode 125. The organic layer 127 includes at least a light emitting layer formed of an organic material, and functions as a light emitting portion of the light emitting element 130. The organic layer 127 includes various layers such as the hole injection layer and / or the hole transport layer, the electron injection layer, and / or the electron transport layer described in FIG. 2 in addition to the light emitting layer. The organic layer 127 is provided to cover the light emitting region. That is, the organic layer 127 is provided to cover the opening of the first insulating layer 126 and the opening of the first insulating layer 126 in the light emitting region.

  In the present embodiment, an organic layer 127 including a light emitting layer which emits light of a desired color is provided. Further, in the present embodiment, by forming the organic layer 127 including different light emitting layers on each pixel electrode 125, each color of RGB is displayed. In the present embodiment, the light emitting layer of the organic layer is discontinuous between the adjacent pixel electrodes 125. The organic layer 127 can be formed of a known structure or a known material, and is not particularly limited to the configuration of this embodiment.

  The counter electrode 128 is formed on the organic layer 127 and the first insulating layer 126. The counter electrode 128 functions as a cathode (cathode) which constitutes the light emitting element 130. The display device 100 according to the present embodiment is a top emission type, and thus the counter electrode 128 uses a transparent electrode. The thin film which comprises a transparent electrode uses a transparent conductive layer using materials, such as a MgAg thin film or ITO and IZO. The counter electrode 128 is also provided on the first insulating layer 126 across the pixel 109R, the pixel 109G, and the pixel 109B. The counter electrode 128 is electrically connected to the external terminal through the lower conductive layer in the peripheral region in the vicinity of the end portion of the display portion 103. As described above, in the present embodiment, the light emitting element 130 is configured by a part (anode) of the pixel electrode 125 exposed from the first insulating layer 126, the organic layer (the light emitting portion) and the counter electrode 128 (the cathode). .

Next, as shown in FIG. 4, in the pixel 109R, the pixel 109G, and the pixel 109B, the optical path length adjusting film 151 and the optical path length adjusting film 154 are formed on each light emitting element. The material for forming the optical path length adjustment film 151 and the optical path length adjustment film 154 can be formed using, for example, an inorganic insulating material such as silicon oxide (SiO ₂ ). Although FIG. 4 shows an example in which the optical path length adjusting film of two layers is formed on each light emitting element, the optical path length adjusting film formed on each light emitting element may be one layer. It may be three or more layers.

  Next, as illustrated in FIG. 5, the organic insulating layer 132 and the inorganic insulating layer 133 are formed over the display portion 103. The organic insulating layer 132 and the inorganic insulating layer 133 function as sealing films for preventing water and oxygen from entering the light emitting element 130. By providing the sealing film over the display portion 103, entry of water or oxygen into the light emitting element 130 can be prevented, and the reliability of the display device can be improved. The material for forming the inorganic insulating layer 133 is, for example, silicon nitride (SixNy), silicon oxynitride (SiOxNy), silicon nitride oxide (SiNxOy), aluminum oxide (AlxOy), aluminum nitride (AlxNy), aluminum oxynitride (AlxOyNz). And aluminum nitride oxide (AlxNyOz), etc. can be used (x, y, z are arbitrary). As a material for forming the organic insulating layer 132, a polyimide resin, an acrylic resin, an epoxy resin, a silicon resin, a fluorine resin, a siloxane resin, or the like can be used. Note that the thickness of the organic insulating layer 132 is 1 μm or more and approximately 20 μm or less. The thickness of the inorganic insulating layer 133 is about 0.1 μm or more and about 3 μm or less.

  Next, as shown in FIG. 6, the counter substrate 102 is attached to the inorganic insulating layer 133 by the adhesive layer 135. As a material for forming the adhesive layer 135, for example, an acrylic, rubber, silicone, or urethane adhesive material can be used. In addition, the adhesive layer 135 may contain a water absorbing substance such as calcium or zeolite. By containing a water absorbing substance in the adhesive layer 135, even when water intrudes into the display device 100, the water can be delayed from reaching the light emitting element 130. In addition, the adhesive layer 135 may be provided with a spacer. By providing the adhesive layer 135 with a spacer, a gap between the first substrate 101 and the counter substrate 102 can be secured. Note that the spacer may be mixed in the adhesive layer 135, or the spacer may be formed of resin or the like on the first substrate 101. In addition, as a material for forming the counter substrate 102, the same material as the material exemplified for the first substrate 101 and the second substrate 112 can be used.

  For example, an overcoat layer may be provided on the counter substrate 102 in order to achieve planarization. Further, when the organic layer emits white light, a color filter corresponding to each color of RGB may be provided on the main surface (surface facing the first substrate 101) on the opposite substrate 102. In addition, a black matrix may be provided between color filters corresponding to each of the RGB colors. Note that in the case where the color filter is not formed on the counter substrate 102 side, for example, the color filter may be formed directly on the sealing film, and the adhesive layer 135 may be formed thereon. In addition, a polarizing plate 138 is provided on the back surface (display surface side) of the counter substrate 102.

2-3. Configuration of End of Display Device FIGS. 7 and 8 are diagrams showing the configuration of a cross section along line A3-A4 of the display unit 103 shown in FIG. 7 and 8 show cross sections of the end portion of the display unit 103 and the peripheral region 110. FIG. 7 and 8 show part of the circuit elements of the scanning signal line drive circuit 104. FIG.

  As shown in FIG. 7, in the peripheral region 110 of the present embodiment, the cathode wiring 142 is stacked on the interlayer insulating layer 122. The cathode wiring 142 is connected to the terminal 107 formed in the peripheral region 110. The contact electrode 131 is stacked on the cathode wire 142. The contact electrode 131 electrically connects the cathode wiring 142 and the counter electrode 128. The counter electrode 128 is stacked on the contact electrode 131. The optical path length adjusting film 151 and the optical path length adjusting film 154 or the optical path length adjusting film 154 are stacked on the counter electrode 128. The organic insulating layer 132 is stacked on the optical path length adjusting film 154. An inorganic insulating layer 133 is stacked on the organic insulating layer 132. Although FIG. 8 shows an example in which optical path length adjusting films of two layers are formed on each light emitting element as in FIG. 4, the optical path length formed on each light emitting element is shown. The adjustment film may be one layer or three or more layers.

  The peripheral region 110 of the present embodiment is in contact with the inorganic insulating layer 133 and the optical path length adjusting film 154, and has a sealing region 140 for sealing the end of the peripheral region 110. In the sealing region 140, the planarization film 123 is stacked on the interlayer insulating layer 122. A protective film 124 is stacked on the planarization film 123. The first insulating layer 126 is stacked on the protective film 124. An optical path length adjusting film 154 is stacked on the first insulating layer 126. An inorganic insulating layer 133 is stacked on the optical path length adjusting film 154.

  Here, for example, the organic insulating layer 132 is formed by inkjet. However, when the organic insulating layer 132 is formed by inkjet, the organic insulating layer 132 flows in the right direction (direction from A3 to A4) in the drawing, and a sealing region that seals the end of the peripheral region 110 140 may not be formed. When the sealing region is not formed, for example, moisture may infiltrate from the peripheral portion of the display device 100 according to an embodiment of the present invention, and the light emitting element 130 may be degraded. By forming the first insulating layer 126 in the sealing region 140, the first insulating layer 126 functions as a bank that prevents the organic insulating layer 132 from flowing in the right direction (direction from A3 to A4) in the drawing. can do. In the present embodiment, the optical path length adjusting film 154 is further formed on the first insulating layer 126, so that the bank becomes double, and the height of the bank can be further increased. Therefore, the effect of preventing the organic insulating layer 132 from flowing in the right direction (the direction from A3 to A4) in the drawing can be enhanced.

  In the present embodiment, the end of the optical path length adjustment film 154 is formed on the protective film 124. Therefore, the end of the optical path length adjustment film 154 is formed such that the protective film 124, the optical path length adjustment film 154, and the inorganic insulating layer 133 are stacked. The protective film 124, the optical path length adjusting film 154, and the inorganic insulating layer 133 are all formed using an inorganic insulating material, so that the adhesion between the layers of the same material can be improved.

  Further, as described above, the inorganic insulating layer 133 and the protective film 124 are formed using an inorganic insulating material such as a silicon nitride film having a barrier function against moisture or oxygen or aluminum oxide. According to the laminating method of the present embodiment, the outer periphery is covered with the inorganic insulating layer 133 and the protective film 124. Therefore, it is possible to prevent the entry of water and oxygen from the upper direction (the direction from the inorganic insulating layer 133 toward the second substrate 112) and the right direction (from the A4 side) in the drawing.

  As described above, in one embodiment of the present invention, each color is synthesized in a wide range of viewing angles by adjusting the order m of the light emitting elements that emit each color under the condition that light in interference of light strengthens each other It is possible to maintain the luminance of white light emission at the time, and to suppress the color change of the white light emission when each color is synthesized in a wide range of the viewing angle. Specifically, blue is emitted by setting at least one of the order mR of the light emitting element emitting red and the order mG of the light emitting element emitting green to be larger than the order mB of the light emitting element emitting blue The luminance viewing angle of the light emitting element can be made relatively wider than the luminance viewing angle of the light emitting element that emits red light and the luminance viewing angle of the light emitting element that emits green light. Further, by widening the luminance viewing angle of the light emitting element emitting blue light, color change can be reduced in a wide range of the luminance viewing angle of white light emission when light emitting and synthesizing each color organic EL material .

  Therefore, according to the present invention, it is possible to provide an organic EL display device in which the luminance is maintained in a wide range of the viewing angle and the color change is small in the wide range of the viewing angle.

3. Second Embodiment In this embodiment, an example in which the arrangement of pixels is different from that of the first embodiment will be described with reference to FIGS. 8 and 9. The description of the same configuration as that of the first embodiment may be omitted.

  FIG. 8 is a diagram showing a part of the pixels provided in the display unit 103. As shown in FIG. One pixel is composed of four pixels, and the four pixels are arranged in two rows in the x direction and in two columns in the y direction. The four pixels are a red pixel 109R, a green pixel 109G, a blue pixel 109B1, and a blue pixel 109B2. Note that in FIG. 8, portions shown as a red pixel 109R, a green pixel 109G, a blue pixel 109B1, and a blue pixel 109B2 are light emitting regions of light emitting elements.

  Moreover, since the cross-sectional view of the light emitting element along the B1-B2 line shown in FIG. 8 is the same as the cross-sectional view of the light emitting element shown in FIG. Note that the blue pixel 109B1 and the blue pixel 109B2 in FIG. 8 have the same structure as the blue pixel 109B in FIG.

  Generally, in the organic EL display device, the deterioration of the light emitting element of the blue pixel is faster than the deterioration of the light emitting element of the red pixel and the light emitting element of the green pixel. As shown in FIG. 8, when one pixel has two blue pixels, the luminance when the number of blue pixels is one is realized by adding the respective luminances of the two blue pixels. As long as the number of blue pixels is one, the energy for causing each of the two blue pixels to emit light is smaller than the energy for causing the one pixel to emit light. Therefore, the speed at which the light emitting element of the blue pixel is deteriorated can be reduced.

  FIG. 9 is a diagram showing a part of the pixels provided in the display unit 103. As shown in FIG. FIG. 10 shows a structure called a so-called diamond pen tile array. In the diamond pen tile array, one pixel includes two red pixels (red pixel 109R1 and red pixel 109R2) and four green pixels (green pixel 109G1, green pixel 109G2 and green pixel 109G3). , Green pixels 109G4) and two blue pixels (blue pixels 109B1 and blue pixels 109B2). In FIG. 9, the red pixel 109R1, the red pixel 109R2, the green pixel 109G1, the green pixel 109G2, the green pixel 109G3, the green pixel 109G4, the blue pixel 109B1, and the blue pixel 109B2 are shown. The portion is a light emitting region of the light emitting element.

  Next, the configuration of the cross section of the light emitting element along C1-C2 in FIG. 9 is the same as the cross sectional view of the light emitting element shown in FIG. The structure of the red pixel 109R1 and the red pixel 109R2 in FIG. 9 is the same as that of the red pixel 109R in FIG. Further, the structure of the green pixel 109G1, the green pixel 109G2, the green pixel 109G3 and the green pixel 109G4 in FIG. 9 is the same as the structure of the green pixel 109G in FIG. Furthermore, the structure of the blue pixel 109B1 and the structure of the blue pixel 109B2 in FIG. 9 are the same as the structure of the blue pixel 109B in FIG.

  By adopting the pen tile array, the number of blue pixels having a high deterioration rate can be reduced as compared with the stripe array. Therefore, according to the present invention, deterioration in display quality of the display device can be suppressed.

  Also in the arrangement of the pixels described in this embodiment, as in the first embodiment, the range of the wide viewing angle is obtained by adjusting the order m of the light emitting elements emitting the respective colors under the condition that light in light interference strengthens each other. Thus, it is possible to maintain the luminance of white light emission when each color is synthesized, and to suppress the color change of the white light emission when each color is synthesized in a wide viewing angle range.

  Therefore, according to the present invention, it is possible to provide an organic EL display device in which the luminance is maintained in a wide range of the viewing angle and the color change is small in the wide range of the viewing angle.

4. Third Embodiment In the present embodiment, an example in which the structure of the light emitting element is different from that of the first embodiment will be described with reference to FIG. Specifically, in the present embodiment, an example in which the optical path length adjustment film is provided also on the counter electrode will be described. By providing the optical path length adjustment film also on the counter electrode, the display device in an embodiment of the present invention can have a structure in which light interferes on the counter electrode. The description of the same configuration as that of the first embodiment or the second embodiment may be omitted.

  FIG. 10 is different from FIG. 2 in that the thickness of the optical path length adjustment film is changed in each of the red pixel 109R, the green pixel 109G, and the blue pixel 109B. The other points are the same in FIG. 10 and FIG. 2, so the description will be omitted.

  In the present embodiment, an optical path length adjustment film 152 and an optical path length adjustment film 153 are further provided on the light path length adjustment film 151 provided on the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B. As a material for forming the optical path length adjusting film 152 and the optical path length adjusting film 153, for example, a general organic material or a transparent conductive material such as ITO is used. The materials for forming the optical path length adjusting film 151, the optical path length adjusting film 152, and the optical path length adjusting film 153 are preferably formed of the same material, in particular, a material having the same refractive index. The refractive index of the optical path length adjustment film 151, the optical path length adjustment film 152, and the optical path length adjustment film 153 is preferably, for example, 1.6 to 2.6.

  The optimum film thickness of the optical path length adjusting film differs depending on the color. For example, when the film thickness of the optical path length adjusting film in the pixel 109R is T1, the film thickness of the optical path length adjusting film in the pixel 109G is T2, and the film thickness of the optical path length adjusting film in the pixel 109B is T3, Let the relationship satisfy T1> T2> T3. In the present embodiment, using the optical path length adjusting film 151, the optical path length adjusting film 152, and the optical path length adjusting film 153, the film thickness of the optical path length adjusting film in pixels of each color is adjusted to satisfy T1> T2> T3. Do.

  Specifically, the optical path length adjustment film 151 is formed to overlap the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B. The optical path length adjustment film 152 is provided on the optical path length adjustment film 151, and is formed to overlap the light emitting element 130R and the light emitting element 130G. The optical path length adjustment film 153 is provided on the optical path length adjustment film 151 and the optical path length adjustment film 152, and is formed to overlap the light emitting element 130R and the light emitting element 130B.

  Although FIG. 10 shows an example in which the optical path length adjusting film 151, the optical path length adjusting film 152, and the optical path length adjusting film 153 are stacked in this order, the stacking order of the optical path length adjusting films in the present invention is It is not limited to this example. The stacking order of the optical path length adjustment film 151, the optical path length adjustment film 152, and the optical path length adjustment film 153 can be changed as appropriate.

  In one embodiment of the present invention, the brightness of white light emission when each color is synthesized in a wide range of viewing angle by adjusting the order m of the light emitting elements emitting the respective colors under the condition that light in interference of light strengthens each other. And the color change of white light emission when each color is synthesized in a wide range of the viewing angle can be suppressed. Specifically, blue is emitted by setting at least one of the order mR of the light emitting element emitting red and the order mG of the light emitting element emitting green to be larger than the order mB of the light emitting element emitting blue The luminance viewing angle of the light emitting element can be made relatively wider than the luminance viewing angle of the light emitting element that emits red light and the luminance viewing angle of the light emitting element that emits green light. Further, by widening the luminance viewing angle of the light emitting element emitting blue light, color change can be reduced in a wide range of the luminance viewing angle of white light emission when light emitting and synthesizing each color organic EL material .

  Further, in one embodiment of the present invention, the optical path length adjusting film light is provided also on the counter electrode. By providing the optical path length adjusting film light also on the counter electrode, the display device in one embodiment of the present invention has a structure in which the light between the pixel electrode and the counter electrode interferes, and a structure in which the light on the counter electrode interferes. And can be provided. The display device in one embodiment of the present invention can further enhance the efficiency of extracting the strongest light from each color by providing two light interference structures.

5. Fourth Embodiment In the present embodiment, an example in which the structure of the light emitting device is different from that of the first embodiment will be described with reference to FIG. Specifically, in this embodiment, an example in which the film thickness of the electron blocking layer is changed in the light emitting element of each color will be described. The description of the same configuration as that of the first to third embodiments may be omitted.

  11 shows that, in each of the red pixel 109R, the green pixel 109G, and the blue pixel 109B, the thickness of the hole transport layer is the same, and the thickness of the electron blocking layer is changed. It is different. The other points are the same as in FIG. 11 and FIG.

  A hole transport layer 162 a is provided on the hole injection layer 161. As described above, the thickness of the hole transport layer 162a is the same in each of the color pixel 109R, the green pixel 109G, and the blue pixel 109B. On the hole transport layer 162a, the electron blocking layer is formed in three divided steps. First, the electron blocking layer 163a is provided in the pixel 109B. Second, the electron blocking layer 163b is provided in the region where the pixel 109R is formed. Third, the electron blocking layer 163c is provided in the region where the pixel 109G is formed. By forming the electron blocking layer in three times, the thickness of the electron blocking layer can be changed for each color of the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B. Therefore, the optical path length can be adjusted for each color of the light emitting element. Therefore, it is possible to resonate and emphasize only the light of the wavelength matching the optical path length, and weaken the light of the wavelength whose optical path length is shifted. Therefore, the spectrum of light extracted to the outside becomes high in intensity, and the luminance and the color purity are improved. The thickness of the electron blocking layer of the pixel 109R is thicker than the thickness of the electron blocking layer of the pixel 109G and the thickness of the electron blocking layer of the pixel 109B. The thickness of the electron blocking layer 163 of the pixel 109G is thicker than the thickness of the electron blocking layer of the pixel 109B.

  In one embodiment of the present invention, the organic layer 127R includes the hole injection layer 161, the hole transport layer 162a, the electron blocking layer 163b, the light emitting layer 164R, the hole blocking layer 165, the electron transport layer 166, and the electron injection layer 167. Have. The organic layer 127G includes a hole injection layer 161, a hole transport layer 162a, an electron blocking layer 163c, a light emitting layer 164G, a hole blocking layer 165, an electron transport layer 166, and an electron injection layer 167. The organic layer 127B includes a hole injection layer 161, a hole transport layer 162a, an electron blocking layer 163a, a light emitting layer 164B, a hole blocking layer 165, an electron transport layer 166, and an electron injection layer 167.

  As described above, in the embodiment of the present invention, by changing the thickness of the electron blocking layer according to the light emitting element emitting light of each color, it is possible to adjust the condition in which light in light interference strengthens. Further, by adjusting the order m of the light emitting element emitting each color under the condition that the light intensifies each other in the light interference, the luminance of the white emission when each color is combined in the wide range of the viewing angle is maintained. It is possible to suppress the color change of white light emission when each color is synthesized in a wide range of angles.

6. Fifth Embodiment In the present embodiment, an example in which the structure of the light emitting element is different from that of the first embodiment will be described with reference to FIG. Specifically, in the present embodiment, an example in which the pixel electrode has a two-layer structure in the light emitting element of each color will be described in this embodiment. The description of the same configuration as that of the first to fourth embodiments may be omitted.

  12 is different from FIG. 2 in that the pixel electrode has a two-layer structure in each of the red pixel 109R, the green pixel 109G, and the blue pixel 109B. The other points are the same in FIG. 12 and FIG. 2, so the description will be omitted.

  The structures of the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B will be described in detail. A pixel electrode is provided for each of the pixel 109R, the pixel 109G, and the pixel 109B. That is, the pixel electrode is provided for each pixel. The pixel electrode has a structure in which two layers of a pixel electrode 125a and a pixel electrode 125b are stacked. The pixel electrode 125a is formed commonly to the pixel 109R, the pixel 109G, and the pixel 109B. Further, the pixel electrode 125a is formed of a reflective material. The pixel electrode 125b, the pixel electrode 125c, and the pixel electrode 125d are formed of a transparent conductive material.

  The transparent conductive material has a high transmittance as compared to the reflective material. For example, the transmittance of the transparent conductive material is 90% or more, and the transmittance of the reflective material is 5% or less.

  The pixel electrode formed of a transparent conductive material is formed in three steps. First, the pixel electrode 125b is provided in the pixel 109B. Second, the pixel electrode 125c is provided in the region where the pixel 109G is formed. Third, the pixel electrode 125d is provided in the region where the pixel 109R is formed. By forming the pixel electrode formed of a transparent conductive material in three times, the film thickness of the pixel electrode formed of a transparent conductive material can be changed to the color of the light emitting element 130R, the light emitting element 130G, and the light emitting element 130B. It can change every time. Therefore, the optical path length can be adjusted for each color of the light emitting element. Therefore, it is possible to resonate and emphasize only the light of the wavelength matching the optical path length, and weaken the light of the wavelength whose optical path length is shifted. Therefore, the spectrum of light extracted to the outside becomes high in intensity, and the luminance and the color purity are improved. The thickness of the pixel electrode 125d of the pixel 109R is thicker than the thickness of the pixel electrode 125c of the pixel 109G and the thickness of the pixel electrode 125b of the pixel 109B. The thickness of the pixel electrode 125c of the pixel 109G is thicker than the thickness of the pixel electrode 125b of the pixel 109B. Note that the order in which the pixel electrode 125b, the pixel electrode 125c, and the pixel electrode 125d are formed is not limited to the order described here. It may be determined appropriately in accordance with the specification and application of the display device.

  As described above, in the embodiment of the present invention, by changing the thickness of the pixel electrode by the light emitting element that emits each color, it is possible to adjust the condition in which light in the light interference intensifies. Further, by adjusting the order m of the light emitting element emitting each color under the condition that the light intensifies each other in the light interference, the luminance of the white emission when each color is combined in the wide range of the viewing angle is maintained. It is possible to suppress the color change of white light emission when each color is synthesized in a wide range of angles.

  The embodiments described above as the embodiments of the present invention can be implemented in combination as appropriate as long as they do not contradict each other. In addition, those in which a person skilled in the art appropriately adds, deletes or changes the design of components based on the display device of each embodiment or those in which steps are added, omitted or conditions changed are also included in the present invention. As long as it comprises the gist, it is included in the scope of the present invention.

  In the present specification, the organic EL display is mainly illustrated as a disclosed example. Another disclosed example is a self-luminous display device that can utilize a microcavity structure that utilizes the resonance effect of light. For example, a self-luminous display device such as an inorganic EL or an LED can be mentioned. In addition, each embodiment described above as the embodiment of the present invention can be applied without particular limitation from the small-sized display device to the large-sized display device.

  Even if other effects or effects different from the effects brought about by the aspects of the above-described embodiments are apparent from the description of the present specification or those which can be easily predicted by those skilled in the art, it is natural. Is understood to be provided by the present invention.

100: display device, 101: first substrate, 102: counter substrate, 103: display portion, 104: scanning signal line drive circuit, 105: scanning signal line, 107: terminal, 108: flexible printed circuit, 109R: pixel, 109R1 : Pixel, 109R2: pixel, 109B: pixel, 109B1: pixel, 109B2: pixel, 109G: pixel, 109G1: pixel, 109G2: pixel, 109G3: pixel, 109G4: pixel, 110: peripheral region, 112: second substrate, 113: base film, 114: semiconductor layer, 115: gate insulating film, 116: gate electrode, 117: drain electrode, 118: drain electrode, 120: transistor, 122: interlayer insulating layer, 123: planarization film, 124: protection Film 125: pixel electrode 125a: pixel electrode 125b: pixel electrode 125c: pixel electrode 125d: pixel electrode 126: first insulating layer 127: organic layer 127R: organic layer 127G: organic layer 127B: organic layer 128: counter electrode 130: light emitting element 130R: light emitting element 130G: light emission Element 130 B: Light emitting element 131: Contact electrode 132: Organic insulating layer 133: Inorganic insulating layer 135: Adhesive layer 138: Polarizing plate 140: Sealing area 142: Cathode wiring 151: Adjustment of optical path length Film 152: optical path length adjusting film 153: optical path length adjusting film 154: optical path length adjusting film 161: hole injection layer 162 a: hole transport layer 162 b: hole transport layer 162 c: hole transport layer , 163: electron blocking layer, 163a: electron blocking layer, 163b: electron blocking layer, 163c: electron blocking layer, 164R: light emitting layer, 164G: emission Layer, 164B: luminescent layer, 165: hole blocking layer, 166: electron transport layer, 167: electron injection layer

Claims (17)

And a display portion provided with a light emitting element,
The light emitting element includes a first electrode electrically connected to a transistor, a light emitting layer provided on the first electrode, and a plurality of layers provided between the first electrode and the light emitting layer. And a second electrode provided on the light emitting layer,
The number of the plurality of layers is k, the refractive index of each layer of the plurality of layers is ni, the film thickness of each layer is di, the wavelength of light of the color emitted by the light emitting element is λ, the interface of the layers Assuming that the length obtained by adding the phase shift due to reflection and the offset length is a, i is a natural number from 1 to k, and the order m is an integer of 0 or more,

And
The light emitting element includes a first light emitting element that emits red light, a second light emitting element that emits green light, and a third light emitting element that emits blue light,
At least one of the order m in the first light emitting element and the order m in the second light emitting element is larger than the order m in the third light emitting element
Display device.   The display device according to claim 1, wherein the order m in the second light emitting element and the order m in the third light emitting element are the same.   The display device according to claim 1, wherein Σdi in the first light emitting element is larger by 150 nm or more than Σdi in the third light emitting element.   The display device according to claim 3, wherein Σdi in the second light emitting element is larger by 120 nm or more than Σdi in the third light emitting element.   The display device according to claim 1, wherein the first electrode comprises a first layer and a second layer, and the second layer has a higher transmittance than the first layer.   The distance between the first electrode and the light emitting layer in the first light emitting element, the distance between the first electrode and the light emitting layer in the second light emitting element, and the distance between the first electrode and the light emitting layer in the third light emitting element The display device according to claim 5, which differs by the thickness of the second layer.   The distance between the first electrode and the light emitting layer in the first light emitting element, the distance between the first electrode and the light emitting layer in the second light emitting element, and the distance between the first electrode and the light emitting layer in the third light emitting element The display device according to claim 1, which differs in thickness of any one of the plurality of layers. And a display portion provided with a light emitting element,
The light emitting element includes a first electrode electrically connected to a transistor, a light emitting layer provided on the first electrode, and a plurality of layers provided between the first electrode and the light emitting layer. And a second electrode provided on the light emitting layer,
The light emitting element includes a first light emitting element that emits red light, a second light emitting element that emits green light, and a third light emitting element that emits blue light,
Assuming that the number of the plurality of layers is k, the thickness of each layer of the plurality of layers is di, and i is a natural number from 1 to k,
Σdi in the first light emitting element is larger by 150 nm or more than Σdi in the third light emitting element;
.SIGMA.di in the first light emitting element is a distance that enhances red light emitted by the first light emitting element, and .SIGMA.di in the third light emitting element is blue light emitted by the third light emitting element A display that is a distance to strengthen.   The display device according to claim 8, wherein Σdi in the second light emitting element is larger by 120 nm or more than Σdi in the third light emitting element.   The display device according to claim 8, wherein the first electrode comprises a first layer and a second layer, and the second layer has a higher transmittance than the first layer.   The distance between the first electrode and the light emitting layer in the first light emitting element, the distance between the first electrode and the light emitting layer in the second light emitting element, and the distance between the first electrode and the light emitting layer in the third light emitting element The display device according to claim 10, which differs by the thickness of the second layer.   The distance between the first electrode and the light emitting layer in the first light emitting element, the distance between the first electrode and the light emitting layer in the second light emitting element, and the distance between the first electrode and the light emitting layer in the third light emitting element The display device according to claim 8, which differs by the thickness of any one of the plurality of layers. And a display portion provided with a light emitting element,
The light emitting element includes a first electrode electrically connected to a transistor, a light emitting layer provided on the first electrode, and an organic layer provided between the first electrode and the light emitting layer. And a second electrode provided on the light emitting layer,
The light emitting element includes a first light emitting element that emits red light, a second light emitting element that emits green light, and a third light emitting element that emits blue light,
The display device in which the thickness of the organic layer in the first light emitting element is larger by 150 nm or more than the thickness of the organic layer in the third light emitting element. The light emitted from the light emitting layer includes a component reflected by the first electrode,
The display device according to claim 13, wherein the thickness of the organic layer is a size in which the component and the other component of the light reinforce each other.   The display device according to claim 13, wherein a thickness of the organic layer in the second light emitting element is larger by 120 nm or more than a thickness of the organic layer in the third light emitting element. The organic layer comprises a plurality of layers,
The display according to any one of claims 13 to 15, wherein a thickness of one layer of the plurality of layers is different in the first light emitting element, the second light emitting element, and the third light emitting element. apparatus. The plurality of layers include a hole injection layer and a hole transport layer,
The one layer is a hole transport layer. The display device according to claim 16.

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