JP2015090810A - El display device, and method of manufacturing el display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an EL display device in which the light extraction efficiency can be enhanced for pixels of output colors different from each other, and to provide a method of manufacturing an EL display device.SOLUTION: An EL display device includes a substrate 11, and a plurality of pixels provided on the substrate 11, each including a cathode layer, an anode layer 16, and an EL layer sandwiched between the cathode layer and anode layer. The EL display device has a micro uneven structure on the interface of the cathode layer and EL layer, the plurality of pixels include more than one type of pixels having output colors different from each other. In each of the more than one type of pixels, the most frequent pitch of the micro uneven structure is set to excite the plasmon light of a wavelength band corresponding to the half-width of the peak, in the emission light spectrum of each pixel.

Description

  The present disclosure relates to an EL display device including a plurality of pixels that emit different light emission colors, and a method for manufacturing the EL display device.

  The EL display device includes a plurality of pixels that emit different light emission colors, and forms an image by emitting light to each pixel. At this time, part of the light generated by the EL element is converted to surface plasmon on the cathode surface of the EL element and consumed as heat. This conversion from surface plasmon to heat is one of the factors that reduce the light extraction efficiency. Therefore, in an EL display device, in order to increase the light extraction efficiency, it has been proposed to form a fine concavo-convex structure which is a repetition of fine concavo-convex on the cathode surface. The fine concavo-convex structure formed on the cathode surface functions as a diffraction grating and converts surface plasmon into plasmon light (see, for example, Patent Documents 1 and 2).

JP 2004-031350 A JP 2009-158478 A

  By the way, unlike an illumination device that emits light of a single color, the EL display device emits light of different colors from pixels of different light emission colors. Then, the EL display device changes the luminance of the light of each color for each pixel and expresses a large number of colors on the surface from which the light is extracted. For example, a red light emitting pixel emits red light, a green light emitting pixel emits green light, and a blue light emitting pixel emits blue light. Then, the control unit of the EL display device controls the luminance of the light with respect to the different light emission color pixels to express a full color image on the surface from which the light is extracted.

  Here, in the fine concavo-convex structure, which is a repetition of fine stepped portions, the range of the emission wavelength converted from surface plasmon to plasmon light is different for each fine concavo-convex structure, and the light emission wavelength at which the brightness is enhanced by a specific fine concavo-convex structure , There are light output wavelengths that cannot be increased. Therefore, in an EL display device that requires different light emission colors, there is still room for improvement from the viewpoint of increasing light extraction efficiency.

  An object of the present disclosure is to provide an EL display device capable of increasing light extraction efficiency for pixels having different light emission colors, and a method for manufacturing the EL display device.

  An EL display device that solves the above problems includes a substrate and a plurality of pixels provided on the substrate. Each of the plurality of pixels includes a cathode layer, an anode layer, and an EL layer sandwiched between the cathode layer and the anode layer, and fine irregularities are formed at an interface between the cathode layer and the EL layer. It has a structure. The plurality of pixels include at least two or more types of pixels having different emission colors. Each of the two or more types of pixels has the fine concavo-convex structure as a plasmonic structure in which a mode pitch is set so as to excite plasmon light included in a wavelength band corresponding to a half width of a peak in a light emission spectrum of the pixel Have

  A manufacturing method of an EL display device that solves the above problem is a manufacturing method of an EL display device that includes a substrate and at least two or more types of pixels that are provided on the substrate and have different light emission colors. Forming a lower electrode layer on the substrate, forming an EL layer on the lower electrode layer, and forming an upper electrode layer on the EL layer. A fine uneven structure is formed at the interface between the EL layer and the cathode layer which is one of the lower electrode layer and the upper electrode layer, and the most frequent pitch of the fine uneven structure includes the fine uneven structure. The fine concavo-convex structure is set so as to excite plasmon light included in a wavelength band corresponding to the half width of the peak in the light emission spectrum of the pixel.

  In the EL display device, the EL layer included in the plurality of pixels emits white light. Each of the two or more types of pixels may include a color filter, and the color filter may emit a specific wavelength band from white light emitted from the EL layer.

In the EL display device, the two or more types of pixels are preferably composed of a red light emitting pixel, a green light emitting pixel, and a blue light emitting pixel.
In the EL display device, the plurality of pixels include white light-emitting pixels, and the fine uneven structure of the white light-emitting pixels has a modest pitch so as to excite plasmon light over the entire wavelength band from which the white light-emitting pixels emit light. Is desirable to be set.

  In the EL display device, one of the cathode layer and the anode layer is a lower electrode layer. Of the cathode layer and the anode layer, a layer different from the lower electrode layer is an upper electrode layer. Each of the plurality of pixels is formed by laminating the lower electrode layer, the EL layer, and the upper electrode layer in this order on a substrate. A fine relief structure having a fine relief structure A at the interface between the lower electrode layer and the EL layer, and having a shape following the shape of the fine relief structure A at the interface between the EL layer and the upper electrode layer. B. Of the fine concavo-convex structure A and the fine concavo-convex structure B, the structure included at the interface between the cathode layer and the EL layer is preferably the fine concavo-convex structure.

In the EL display device, the average height of the concavo-convex structure in the fine concavo-convex structure A is preferably equal to or higher than the average height of the concavo-convex structure in the fine concavo-convex structure B.
In the EL display device, between the substrate and the lower electrode layer, a pixel circuit connected to a part of the lower electrode layer and supplying current to the EL layer, and the pixels of the pixels adjacent to each other And an insulating layer that insulates the circuits from each other. The fine unevenness having a fine concavo-convex structure C at the interface between the insulating layer and the lower electrode layer, and having a shape following the shape of the fine concavo-convex structure C at the interface between the lower electrode layer and the EL layer. Preferably it has structure A.

In the EL display device, the average height of the concavo-convex structure in the fine concavo-convex structure C is preferably equal to or higher than the average height of the concavo-convex structure in the fine concavo-convex structure A.
The method for manufacturing an EL display device further includes the step of forming a fine concavo-convex structure D on the substrate, the fine concavo-convex structure has a shape following the fine concavo-convex structure D, and the fine concavo-convex structure The average height of the concavo-convex structure in is preferably equal to or less than the average height of the concavo-convex structure in the fine concavo-convex structure D.

  In the EL display device manufacturing method, the substrate has an insulating layer, and in the step of forming the lower electrode layer, the lower electrode layer is formed on the insulating layer, and the fine concavo-convex structure D is formed. In the step, it is preferable to form the fine uneven structure D on the insulating layer.

  According to the technique of the present disclosure, the light extraction efficiency is improved for pixels having different light emission colors.

It is a block diagram which shows the structure of the red light emission pixel in 1st Embodiment by which the EL display apparatus in the technique of this indication was actualized by the EL display apparatus provided with the light emitting layer for each color. It is a block diagram which shows the structure of the green light emission pixel in 1st Embodiment. It is a block diagram which shows the structure of the blue light emission pixel in 1st Embodiment. It is process drawing which shows the manufacturing method of EL display apparatus in 1st Embodiment. It is a block diagram which shows the structure of the red light emission pixel in 2nd Embodiment by which the EL display apparatus in the technique of this indication was actualized by the EL display apparatus provided with the light emitting layer for each color. It is process drawing which shows the manufacturing method of the EL display apparatus in 2nd Embodiment. It is a block diagram which shows the structure of the red light emission pixel in 3rd Embodiment actualized to the EL display apparatus with which the EL display apparatus in the technique of this indication is equipped with the light emitting layer for each color. It is process drawing which shows the manufacturing method of EL display apparatus in 3rd Embodiment. It is sectional drawing which shows an example of the layer structure of EL display apparatus in 3rd Embodiment. It is a block diagram which shows the structure of each color light emission pixel in 4th Embodiment by which the EL display apparatus in the technique of this indication was actualized by the EL display apparatus provided with the light emitting layer for white. It is a block diagram which shows the structure of each color light emission pixel in 5th Embodiment embodied by the EL display device provided with the white light emission pixel in the EL display apparatus in the technique of this indication.

[First Embodiment]
With reference to FIGS. 1 to 4, a first embodiment in which an EL display device according to the present disclosure is embodied as an EL display device including light emitting layers for three different colors will be described. The EL display device according to the first embodiment includes a plurality of red light emission pixels, a plurality of green light emission pixels, and a plurality of blue light emission pixels, which are pixels for three colors having different light emission colors. The red light emitting pixel emits red light, the green light emitting pixel emits green light, and the blue light emitting pixel emits blue light.

[Red light emission pixel 10R]
As shown in FIG. 1, the red light output pixel 10 </ b> R includes a red driving unit 20 </ b> R positioned on the substrate 11 and a red EL structure 30 </ b> R positioned on the red driving unit 20 </ b> R. The red driving unit 20R and the red EL structure 30R are electrically connected.

  The red driving unit 20R supplies a driving current for causing the red light emitting pixel 10R to emit light to the EL structure 30R for red. The red driving unit 20R includes a red pixel circuit 12R and an insulating layer 13 that covers the red pixel circuit 12R. The red pixel circuit 12R supplies a drive current to the red EL structure 30R. The insulating layer 13 is sandwiched between the red pixel circuit 12R and the red EL structure 30R. The insulating layer 13 restricts electrical contact between the red pixel circuit 12R and the red EL structure 30R, and insulates adjacent pixel circuits. The surface in contact with the red EL structure 30R in the insulating layer 13 is a flat surface.

  The red EL structure 30 </ b> R includes a red cathode layer 14 </ b> R, a red EL layer 15 </ b> R, and an anode layer 16. The red cathode layer 14R is connected to the red driving unit 20R through the insulating layer 13, and the red driving unit 20R supplies a driving current to the red cathode layer 14R. The anode layer 16 is connected to a common power source.

  When a current flows between the anode layer 16 and the red cathode layer 14R, holes are injected from the anode layer 16 into the red EL layer 15R, and the red cathode layer 14R to the red EL layer 15R. Electrons are injected into the. The red EL layer 15R generates red light by the combination of holes and electrons injected into the red EL layer 15R. Red light has a spectrum different from that of green light and blue light, and shows a broad peak between, for example, 620 nm and 750 nm.

  The red cathode layer 14R may have a function of reflecting red light or a function of transmitting red light. When the red cathode layer 14R has a function of reflecting red light, the anode layer 16 has a light-transmitting property of transmitting red light, and the EL display device functions as a top emission type. When the cathode layer 14R for red has a function of transmitting red light, the anode layer 16 has light reflectivity for reflecting red light, and the EL display device functions as a bottom emission type. When the red cathode layer 14R reflects red light, the red cathode layer 14R may be composed of one layer that reflects red light, or a layer having a function of transmitting red light. And a multilayer structure including a reflective layer that reflects red light.

  The red cathode layer 14R has a red cathode surface 4RS that constitutes an interface between the red EL layer 15R and the red cathode layer 14R. The cathode surface 4RS for red has a fine concavo-convex structure for red, which is composed of a plurality of steps repeated on the cathode surface 4RS. The fine concavo-convex structure for red is a plasmonic structure. In the plasmonic structure for red, the interval between adjacent step portions is a red pitch 4CR, and the size of each step is for red. The level difference is 4RH. In the plasmonic structure for red, the pitch 4CR for red is a periodic length in which the step portion is repeated on the cathode surface 4RS for red.

  The pitch 4CR for red is set to a size that allows surface plasmons generated when red light is generated to be taken out into the air as red light. The mode pitch, which is the mode value of the red pitch 4CR, is set such that the red plasmonic structure excites plasmon light when the red EL layer 15R emits light. The wavelength of the plasmon light excited by the plasmonic structure is determined by the interval between the step portions adjacent to each other. The wavelength of the plasmon light generated by the red plasmonic structure is included in the wavelength band corresponding to the half width of the peak in the emission spectrum, which is the spectrum of the light emitted from the red emission pixel 10R. Note that, in the light emission peak of the red light emission pixel 10R, the maximum luminance value is determined as the maximum luminance, and the interval between the two wavelengths indicating the half value of the maximum luminance is determined as the half width of the red peak. Then, a wavelength band corresponding to the half-value width of the red peak is defined between the two wavelengths indicating half the maximum luminance.

  The mode value of the red pitch 4CR is obtained as follows. That is, in the cathode surface 4RS on which the red plasmonic structure is formed, a square measurement target region that is approximately 30 to 40 times the most frequent pitch of the red pitch 4CR is randomly extracted. Next, an atomic force microscope image for the measurement target region is obtained. For example, when the most frequent pitch is 10 μm, an atomic force microscope image is obtained for a measurement target region of 300 μm × 300 μm to 400 μm × 400 μm. In addition, the atomic force microscope image obtained here is an image obtained by planar view of the plasmonic structure. Subsequently, the atomic force microscope image is waveform-separated by Fourier transform to obtain a fast Fourier transform image. Then, the distance from the zero-order peak to the first-order peak in the profile of the fast Fourier transform image is obtained, and the reciprocal of the distance thus obtained is handled as the most frequent pitch in the measurement target region.

  By the same method as described above, the most frequent pitch is obtained for each of 25 different measurement target regions. The average value of the most frequent pitches in the 25 measurement objects is handled as the most frequent pitch Px in the red plasmonic structure. At this time, the measurement target regions are preferably selected at least 1 mm apart, more preferably 5 mm or more and 1 cm or less apart.

  Regarding the degree to which the surface plasmon generated when red light is generated is converted into red radiation light, the contribution of the red step 4RH is smaller than the contribution of the red pitch 4CR. In the configuration in which the red step 4RH is less than 12 nm, it is difficult to generate the diffracted wave itself of the surface plasmon, and therefore it is difficult to extract the surface plasmon as radiant light. In the configuration in which the red step 4RH exceeds 180 nm, the surface plasmon is localized, and therefore it is difficult to extract the surface plasmon as radiation light. In the configuration where the red step 4RH exceeds 180 nm, the red cathode layer 14R and the anode layer 16 are easily short-circuited in the portion where the red EL layer 15R is excessively thin due to the large step. .

  The anode layer 16 is a layer common to the red light output pixel 10R, the green light output pixel 10G, and the blue light output pixel 10B. The anode layer 16 may have a function of reflecting visible light or may have a function of transmitting visible light. When the anode layer 16 has a function of reflecting visible light, the red cathode layer 14R has a light-transmitting property of transmitting red light, and the EL display device functions as a bottom emission type. When the anode layer 16 has a function of transmitting visible light, the red cathode layer 14R has a light reflecting property of reflecting red light, and the EL display device functions as a top emission type. When the anode layer 16 reflects visible light, the anode layer 16 may be composed of one layer that reflects visible light, or a layer having a function of transmitting visible light, and visible A multilayer structure including a reflective layer that reflects light may be used.

  The red EL layer 15R includes a red light emitting layer. The red light emitting layer combines the electrons sent from the red cathode layer 14R and the holes sent from the red anode layer to generate red light. The red EL layer 15R may include a functional layer other than the red light-emitting layer in order to generate red light. The red EL structure 30 </ b> R preferably includes a functional layer other than the red light emitting layer in order to increase the generation efficiency of red light. The red EL structure 30 </ b> R may be configured by only the red light-emitting layer, omitting other functional layers. The material constituting the EL structure 30R for red is not particularly limited as long as it is a material that generates red light, and may be a low molecular weight organic material, a high molecular organic material, or an inorganic material. Good materials can be used.

  The red plasmonic structure is a step structure in which a plurality of step portions are repeated on the red cathode surface 4RS. The red plasmonic structure may be a one-dimensional periodic structure in which a plurality of stepped portions are repeated along the one-dimensional direction, but a two-dimensional periodic structure is preferable in terms of increasing light extraction efficiency.

  The red plasmonic structure is, for example, a two-dimensional lattice structure in which stepped portions are arranged at lattice points periodically located in the two-dimensional direction. The two-dimensional lattice structure is a structure in which stepped portions are arranged along at least two directions. One example of the two-dimensional lattice structure is a square lattice structure in which stepped portions are arranged along two different directions, and an angle formed by the two directions of the stepped portions is 90 °. One example of the two-dimensional lattice structure is a hexagonal lattice structure in which stepped portions are arranged along three different directions, and an angle formed by two directions among the three directions in which the stepped portions are arranged is 60 °.

  The step portion in the red plasmonic structure may be constituted by a plurality of protrusions protruding at the red cathode surface 4RS, or may be formed by a plurality of depressions recessed at the red cathode surface 4RS. Good.

  When the step portion in the red plasmonic structure is constituted by a protrusion, the shape of the protrusion is not particularly limited as long as it is a shape protruding at the red cathode surface 4RS. It may be a shape, a hemispherical shape, a pyramid shape, a prism shape, a truncated cone shape, a truncated pyramid shape, or a shape derived from one of these.

  When the stepped portion in the red plasmonic structure is configured by a recess, the shape of the recess is not particularly limited as long as the recess is recessed at the red cathode surface 4RS. The shape of the dent may be, for example, a circular hole shape, a square hole shape, a circular hole shape whose diameter is reduced along the depth direction, or a square hole shape whose diameter is reduced along the depth direction.

  When the red light emitting layer generates light, near-field light is generated in the vicinity of the red light emitting layer. The distance between the red light emitting layer and the red cathode layer 14R is so short that surface plasmons are generated on the red cathode surface 4RS. Field light is converted to surface plasmons.

  Here, the surface plasmon generated on the red cathode surface 4RS is a state in which a density wave of free electrons generated by near-field light is accompanied by a surface electromagnetic field. When the red cathode surface is a flat surface, the surface plasmon dispersion curve generated on the flat metal surface and the red light dispersion curve do not intersect, so the surface plasmon energy is not extracted as light, Generally consumed as heat.

  In contrast, when the red cathode surface 4RS has a red plasmonic structure, the dispersion curve of light diffracted by the red plasmonic structure and the surface plasmon generated on the red cathode surface 4RS Intersects with the dispersion curve. As a result, the energy of the surface plasmon generated when red light is generated is extracted as red radiant light.

  Note that the shorter the distance between the red cathode surface 4RS and the red light emitting layer, the easier the light generated by the red light emitting layer is converted to surface plasmons at the red cathode surface 4RS. The red EL layer 15R may include a functional layer other than the red light emitting layer in order to generate red light, but the distance between the red light emitting layer and the red cathode surface 4RS is The shorter it is, the higher the effect of extracting red radiation light.

[Green light-emitting pixel 10G]
As shown in FIG. 2, the green light emitting pixel 10G includes a green driving unit 20G and a green EL structure 30G located on the green driving unit 20G on the substrate 11 common to the red light emitting pixel 10R. It has. The green driving unit 20G and the green EL structure 30G are electrically connected.

  The green driving unit 20G supplies a driving current for causing the green light emitting pixel 10G to emit light to the green EL structure 30G. The green driving unit 20G includes a green pixel circuit 12G that generates a driving current and an insulating layer 13 that covers the green pixel circuit 12G. The green pixel circuit 12G has a configuration corresponding to the red pixel circuit 12R in the red pixel 10R in the green pixel 10G. The insulating layer 13 is common to the red light emitting pixel 10R, and the green light emitting pixel 10G has a configuration corresponding to the insulating layer 13 in the red light emitting pixel 10R.

  The green EL structure 30 </ b> G includes a green cathode layer 14 </ b> G, a green EL layer 15 </ b> G, and an anode layer 16. The green cathode layer 14G is connected to the green driving unit 20G through the insulating layer 13, and the green driving unit 20G supplies a driving current to the green cathode layer 14G. When a current flows between the anode layer 16 and the green cathode layer 14G, holes are injected from the anode layer 16 to the green EL layer 15G, and the green cathode layer 14G to the green EL layer 15G. Electrons are injected into the. The green EL layer 15G generates green light by the combination of holes and electrons injected into the green EL layer 15G. Green light has a wavelength different from that of red light and blue light, and shows a broad peak between, for example, 495 nm and 570 nm.

  Similarly to the red cathode layer 14R, the green cathode layer 14G may have a function of reflecting green light or a function of transmitting green light. When the green cathode layer 14G has a function of reflecting green light, the anode layer 16 has a light transmission property of transmitting green light, and the EL display device functions as a top emission type. When the green cathode layer 14G has a function of transmitting green light, the anode layer 16 has light reflectivity for reflecting green light, and the EL display device functions as a bottom emission type.

  The green cathode layer 14G has a green cathode surface 4GS that constitutes an interface between the green EL layer 15G and the green cathode layer 14G. The green cathode surface 4GS has a fine concavo-convex structure for green consisting of a plurality of steps repeated on the cathode surface 4GS. The fine concavo-convex structure for green is a plasmonic structure, and in the plasmonic structure for green, the interval between adjacent step portions is a green pitch 4CG, and the size of each step is for green The level difference is 4GH. In the green plasmonic structure, the green pitch 4CG is a repeated cycle length of the stepped portion.

  The green pitch 4CG is a size that allows surface plasmons generated when green light is generated to be extracted into the air as green light. The mode pitch, which is the mode value of the green pitch 4CG, is set such that the green plasmonic structure excites plasmon light when the green EL layer 15G emits light. The wavelength of the plasmon light excited by the plasmonic structure is determined by the interval between the step portions adjacent to each other. The wavelength of the plasmon light generated by the green plasmonic structure is included in the wavelength band corresponding to the half width of the peak in the light emission spectrum that is the spectrum of the light emitted from the green light emission pixel 10G.

  Note that, in the light emission peak of the green light emission pixel 10G, the maximum luminance value is determined as the maximum luminance, and the interval between the two wavelengths indicating the half value of the maximum luminance is determined as the half width of the green peak. Then, a wavelength band corresponding to the half-value width of the green peak is defined between two wavelengths indicating half the maximum luminance. The mode pitch of the green pitch 4CG is a value obtained in the same manner as the mode pitch of the red pitch 4CR, and is smaller than the mode pitch of the red pitch 4CR.

  Regarding the degree to which the surface plasmon generated when green light is generated is converted into green radiant light, the contribution of the green step 4GH is smaller than the contribution of the green pitch 4CG. When the green step 4GH is 12 nm or more and 180 nm or less, the surface plasmon generated when green light is generated is easily extracted as green radiant light. In the configuration in which the green step 4GH is less than 12 nm, it is difficult to generate the diffracted wave of the surface plasmon itself, and therefore it is difficult to extract the surface plasmon as radiation light. In the configuration in which the step 4GH for green exceeds 180 nm, the surface plasmon is localized, so it is difficult to extract the surface plasmon as radiant light. In addition, in the configuration where the green step 4GH exceeds 180 nm, the green cathode layer 14G and the anode layer 16 are easily short-circuited in the portion where the green EL layer 15G is excessively thin due to the large step. .

  The green EL layer 15G includes a green light emitting layer. The green light emitting layer combines the electrons sent from the green cathode layer 14G and the holes sent from the green anode layer to generate green light. The green EL layer 15G may include a functional layer other than the green light-emitting layer in order to generate green light. The green EL structure 30G preferably includes a functional layer other than the green light-emitting layer in order to increase the generation efficiency of green light. The green EL structure 30 </ b> G may be configured by only the green light-emitting layer, omitting other functional layers. The material constituting the green EL structure 30G is not particularly limited as long as it is a material that generates green light, and may be a low molecular organic material, a high molecular organic material, or an inorganic material. Good materials can be used.

  The green plasmonic structure is a step structure in which a plurality of step portions are repeated on the green cathode surface 4GS. The green plasmonic structure may be a one-dimensional periodic structure in which a plurality of stepped portions are repeated along the one-dimensional direction, but a two-dimensional periodic structure is preferable in terms of increasing light extraction efficiency.

  The green plasmonic structure is, for example, a two-dimensional lattice structure in which stepped portions are arranged at lattice points that are periodically located in the two-dimensional direction, like the red plasmonic structure. The step portion in the green plasmonic structure may be formed by a plurality of protrusions protruding at the green cathode surface 4GS, or may be formed by a plurality of recesses recessed at the green cathode surface 4GS. Good.

  When the step portion in the green plasmonic structure is constituted by a protrusion, the shape of the protrusion is not particularly limited as long as it is a shape protruding from the green cathode surface 4GS. It may be a shape, a hemispherical shape, a pyramid shape, a prism shape, a truncated cone shape, a truncated pyramid shape, or a shape derived from one of these.

  When the stepped portion in the green plasmonic structure is configured by a recess, the shape of the recess is not particularly limited as long as it is a shape that is recessed on the green cathode surface 4GS. The shape of the dent may be, for example, a circular hole shape, a square hole shape, a circular hole shape whose diameter is reduced along the depth direction, or a square hole shape whose diameter is reduced along the depth direction.

  When the green light emitting layer generates light, near-field light is generated in the vicinity of the green light emitting layer. The distance between the green light emitting layer and the green cathode layer 14G is so short that near-field light is generated on the green cathode surface 4GS. Field light is converted to surface plasmons. The green cathode surface 4GS has a function according to the function of the red cathode surface 4RS in the red light emitting pixel 10R in the green light emitting pixel 10G, and the surface plasmon converted by the green cathode surface 4GS is: Extracted as green radiant light.

  As the distance between the green cathode surface 4GS and the green light emitting layer is shorter, the light generated by the green light emitting layer is more easily converted into surface plasmons at the green cathode surface 4GS. The green EL layer 15G may include a functional layer other than the green light emitting layer in order to generate green light, but the distance between the green light emitting layer and the green cathode surface 4GS is It is preferable that the length is as short as possible without causing short circuit.

[Blue light emission pixel 10B]
As shown in FIG. 3, the blue light emitting pixel 10B includes a blue driving unit 20B and a blue EL structure 30B located on the blue driving unit 20B on the substrate 11 common to the red light emitting pixel 10R. It has. The blue driving unit 20B and the blue EL structure 30B are electrically connected.

  The blue driving unit 20B supplies a driving current for causing the blue light emitting pixel 10B to emit light to the blue EL structure 30B. The blue drive unit 20B includes a blue pixel circuit 12B that generates a drive current and an insulating layer 13 that covers the blue pixel circuit 12B. The blue pixel circuit 12B has a configuration corresponding to the red pixel circuit 12R in the red pixel 10R in the blue pixel 10B. The insulating layer 13 is common to the red light emitting pixel 10R, and the blue light emitting pixel 10B has a configuration corresponding to the insulating layer 13 in the red light emitting pixel 10R.

  The blue EL structure 30 </ b> B includes a blue cathode layer 14 </ b> B, a blue EL layer 15 </ b> B, and an anode layer 16. The blue cathode layer 14B is connected to the blue drive unit 20B through the insulating layer 13, and the blue drive unit 20B supplies a drive current to the blue cathode layer 14B. When a current flows between the anode layer 16 and the blue cathode layer 14B, holes are injected from the anode layer 16 into the blue EL layer 15B, and the blue cathode layer 14B to the blue EL layer 15B. Electrons are injected into the. The blue EL layer 15B generates blue light by the combination of holes and electrons injected into the blue EL layer 15B. Blue light has a wavelength different from that of red light and green light, and exhibits a broad peak between 450 nm and 495 nm, for example.

  Similarly to the red cathode layer 14R, the blue cathode layer 14B may have a function of reflecting blue light or a function of transmitting blue light. When the blue cathode layer 14B has a function of reflecting blue light, the anode layer 16 has a light transmitting property of transmitting blue light, and the EL display device functions as a top emission type. When the blue cathode layer 14B has a function of transmitting blue light, the anode layer 16 has light reflectivity for reflecting blue light, and the EL display device functions as a bottom emission type.

  The blue cathode layer 14B has a blue cathode surface 4BS that constitutes an interface between the blue EL layer 15B and the blue cathode layer 14B. The blue cathode surface 4BS has a blue fine concavo-convex structure composed of a plurality of stepped portions repeated on the cathode surface 4BS. The fine concavo-convex structure for blue is a plasmonic structure, and in the plasmonic structure for blue, an interval between adjacent step portions is a blue pitch 4CB, and the size of each step is for blue The level difference is 4BH. In the blue plasmonic structure, the blue pitch 4CB is a periodic length of the stepped portion.

  The blue pitch 4CB has such a size that surface plasmons generated when blue light is generated are extracted into the air as blue light. The mode pitch, which is the mode value of the blue pitch 4CB, is set so that the plasmonic structure for blue excites plasmon light when the EL layer 15B for blue emits light. The wavelength of the plasmon light excited by the plasmonic structure is determined by the interval between the step portions adjacent to each other. The wavelength of the plasmon light generated by the blue plasmonic structure is included in the wavelength band corresponding to the half width of the peak in the emission spectrum, which is the spectrum of the light emitted from the blue emission pixel 10B.

  Note that, at the light emission peak of the blue light emission pixel 10B, the maximum luminance value is determined as the maximum luminance, and the interval between the two wavelengths indicating the half value of the maximum luminance is determined as the half-value width of the blue peak. Then, a wavelength band corresponding to the half-value width of the blue peak is defined between two wavelengths that show a half value of the maximum luminance. The mode value of the blue pitch 4CB is a value obtained in the same manner as the mode value of the red pitch 4CR and the green pitch 4CG, is smaller than the mode pitch of the red pitch 4CR, and further, the green pitch 4CG. Is less than the most frequent pitch.

  Regarding the degree to which surface plasmons generated during the generation of blue light are converted into blue radiation, the contribution of the blue step 4BH is smaller than the contribution of the blue pitch 4CB. In the configuration in which the level difference 4BH for blue is less than 12 nm, it is difficult to generate the diffracted wave of the surface plasmon, and therefore it is difficult to extract the surface plasmon as radiation light. In the configuration in which the level difference 4BH for blue exceeds 180 nm, surface plasmons are localized, so that it is difficult to extract the surface plasmons as radiation light. Further, in the configuration in which the blue step 4BH exceeds 180 nm, the blue cathode layer 14B and the anode layer 16 are easily short-circuited in the portion where the blue EL layer 15B is excessively thin due to the large step. .

  The blue EL layer 15B includes a blue light emitting layer. The blue light emitting layer combines the electrons sent from the blue cathode layer 14B and the holes sent from the blue anode layer to generate blue light. The blue EL layer 15B may include a functional layer other than the blue light-emitting layer in order to generate blue light. The blue EL structure 30 </ b> B preferably includes a functional layer other than the blue light-emitting layer in order to increase the generation efficiency of blue light. The blue EL structure 30 </ b> B may be composed of only the blue light-emitting layer, omitting other functional layers. The material constituting the EL structure 30B for blue is not particularly limited as long as it is a material that generates blue light, and may be a low molecular organic material, a high molecular organic material, or an inorganic material. Good materials can be used.

  The blue plasmonic structure is a step structure in which a plurality of step portions are repeated on the blue cathode surface 4BS. The blue plasmonic structure may be a one-dimensional periodic structure in which a plurality of stepped portions are repeated along the one-dimensional direction, but a two-dimensional periodic structure is preferable in terms of increasing light extraction efficiency.

  The blue plasmonic structure is, for example, a two-dimensional lattice structure in which stepped portions are arranged at lattice points that are periodically located in the two-dimensional direction, similarly to the plasmonic structure for red. The step portion in the blue plasmonic structure may be constituted by a plurality of protrusions protruding at the blue cathode surface 4BS, or may be constituted by a plurality of depressions recessed at the blue cathode surface 4BS. Good.

  When the step portion in the blue plasmonic structure is constituted by a protrusion, the shape of the protrusion is not particularly limited as long as it is a shape protruding at the blue cathode surface 4BS, for example, a conical shape, a cylinder It may be a shape, a hemispherical shape, a pyramid shape, a prism shape, a truncated cone shape, a truncated pyramid shape, or a shape derived from one of these.

  When the stepped portion in the blue plasmonic structure is constituted by a dent, the shape of the dent is not particularly limited as long as it is a shape that dents on the blue cathode surface 4BS. The shape of the dent may be, for example, a circular hole shape, a square hole shape, a circular hole shape whose diameter is reduced along the depth direction, or a square hole shape whose diameter is reduced along the depth direction.

  When the blue light emitting layer generates light, near-field light is generated in the vicinity of the blue light emitting layer. The distance between the blue light emitting layer and the blue cathode layer 14B is so short that near-field light is generated at the blue cathode surface 4BS. Field light is converted to surface plasmons. The blue cathode surface 4BS has a function corresponding to the function of the red cathode surface 4RS in the red light emitting pixel 10R in the blue light emitting pixel 10B, and the surface plasmon converted by the blue cathode surface 4BS is Extracted as blue radiant light.

  Note that the shorter the distance between the blue cathode surface 4BS and the blue light emitting layer, the easier the light generated by the blue light emitting layer is converted to surface plasmons at the blue cathode surface 4BS. The blue EL layer 15B may include a functional layer other than the blue light emitting layer in order to generate blue light, but the distance between the blue light emitting layer and the blue cathode surface 4BS is Shorter is preferable.

[Plasmonic structure for each color]
The red pitch 4CR is the distance between the centers of the protrusions of the red cathode surface 4RS or the distance between the centers of the recesses of the red cathode surface 4RS in the plan view of the red cathode surface 4RS. It is. The green pitch 4CG is the distance between the centers of the protrusions of the green cathode surface 4GS or the distance between the centers of the recesses of the green cathode surface 4GS in the plan view of the green cathode surface 4GS. It is. The blue pitch 4CB is the distance between the centers of the protrusions of the blue cathode surface 4BS or the distance between the centers of the depressions of the blue cathode surface 4GS in the plan view of the blue cathode surface 4BS. It is. In addition to the method using an atomic force microscope image, for example, the pitches 4CR, 4CG, 4CB for each color are indirectly measured as a lattice constant of a two-dimensional lattice structure. A so-called laser diffraction method is used.

  The red pitch 4CR and the red step 4RH may be set based on a numerical calculation result using a rigorous coupled analysis (RCWA: Rigorous Coupled-Wave Analysis). Further, the red pitch 4CR and the red step 4RH are based on various experiments for directly measuring the luminance in the red light emitting pixel 10R with respect to combinations of a plurality of different red pitches 4CR and red steps 4RH. It may be set.

Strict coupling analysis is a kind of differential method among strict electromagnetic field analysis methods of a lattice structure on the assumption that the electric and magnetic fields are vector fields. In exact coupling analysis, a diffraction grating is expressed by Fourier series expansion, a coupling equation between the diffraction grating and an electromagnetic field is obtained, and this is numerically solved under boundary conditions to calculate diffraction efficiency (for example, L , Li “New formulation of Fourier modal method for crossed surface-relief gratings,” J.Opt.Soc.Am.A 14,2758-2767 (1997))
When the strict coupling analysis is used, for example, it is assumed that the red light generated in the red EL layer 15R is perpendicularly incident on the red cathode surface 4RS as a plane wave. . Next, the reflectance by the strict coupling analysis is calculated under a plurality of different conditions. Under each of a plurality of different conditions, the red pitch 4CR and the red step 4RH are statistically changed. And among all the red pitches 4CR and the red steps 4RH, the combination of the red pitch 4CR and the red steps 4RH showing a relatively small reflectance is an effective configuration for the conversion of the surface plasmon. Determined.

  The green pitch 4CG and the green step 4GH are also determined by the same method as the red pitch 4CR and the red step 4RH. The blue pitch 4CB and the blue step 4BH are also determined by the same method as the red pitch 4CR and the red step 4RH.

  Whether the exact coupling analysis is used or when various experiments are used, the two-dimensional period is increased as the wavelength band of the color represented by each of the color output light pixels 10R, 10G, and 10B is located on the short wavelength side. With a configuration in which the period in the structure is short, the luminance at each wavelength is increased.

  That is, in the configuration in which the distance between the adjacent stepped portions in the fine concavo-convex structure is smaller as the wavelength band of the color expressed by each of the color output pixels 10R, 10G, and 10B is located on the shorter wavelength side, Brightness is increased. Then, with the configuration in which the pitch 4CR for red, the pitch 4CG for green, and the pitch 4CB for blue are reduced in this order, the surface plasmon is converted into radiation light in each of the red light emission pixel 10R, the green light emission pixel 10G, and the blue light emission pixel 10B. The light extraction efficiency at each pixel is increased. The light extraction efficiency is the ratio of the light emitted by the light emitting layer for each color to the light emitted from the front surface of the pixel in the pixel corresponding to the light emitting layer.

[Method for Manufacturing EL Display Device]
As shown in FIG. 4, the manufacturing method of the EL display device includes a pixel circuit forming step S11, an insulating layer forming step S12, a cathode layer forming step S13, a plasmonic structure forming step S14, an EL layer forming step S15, and an anode layer forming. Step S16 is included.

  In the pixel circuit formation step S11, a plurality of red pixel circuits 12R, a plurality of green pixel circuits 12G, and a plurality of blue pixel circuits 12B are formed on the substrate 11. A method for forming the pixel circuit is not particularly limited, and a known circuit formation technique such as various materials, a film formation method, a patterning method, or the like is used depending on the structure of the element included in the pixel circuit.

  In the insulating layer forming step S12, first, the insulating layer 13 is formed so that one insulating layer 13 covers the whole of the plurality of red pixel circuits 12R, the plurality of green pixel circuits 12G, and the plurality of blue pixel circuits 12B. Is done. Next, a plurality of contact holes communicating with each of the plurality of red pixel circuits 12R, each of the plurality of green pixel circuits 12G, and each of the plurality of blue pixel circuits 12B are provided in the insulating layer for each of the pixel circuits 12R, 12G, and 12B. 13 is formed. The method for forming the insulating layer 13 is not particularly limited, and a known film formation technique such as a plasma CVD method or a coating method is used.

  In the cathode layer forming step S13, the cathode layer 14R, the material constituting the cathode layer is embedded in each of the plurality of contact holes, and the cathode layer is independent for each of the pixel circuits 12R, 12G, 12B. 14G and 14B are formed.

  Above each of the plurality of red pixel circuits 12R, a red cathode layer 14R connected to the red pixel circuit 12R is formed for each red pixel circuit 12R. Above each of the plurality of green pixel circuits 12G, a green cathode layer 14G connected to the green pixel circuit 12G is formed for each green pixel circuit 12G. Above each of the plurality of blue pixel circuits 12B, a blue cathode layer 14B connected to the blue pixel circuit 12B is formed for each blue pixel circuit 12B.

  The method for forming the cathode layers 14R, 14G, and 14B for each color is not particularly limited, and a known electrode forming technique such as a film forming method or a patterning method is used. For example, the cathode layers 14R, 14G, 14B for each color are formed by sputtering using a metal mask having an opening corresponding to the planar shape of the cathode layers 14R, 14G, 14B. Alternatively, each color cathode layer 14R, 14G, 14B is formed by sputtering a conductive film made of a material constituting each color cathode layer 14R, 14G, 14B, and the conductive film is patterned with a photoresist. It is formed by the subsequent etching.

  In the plasmonic structure forming step S14, a red plasmonic structure is formed on the cathode surface 4RS of the red cathode layer 14R. Also, a green plasmonic structure is formed on the cathode surface 4GS of the green cathode layer 14G. Furthermore, a blue plasmonic structure is formed on the cathode surface 4BS of the blue cathode layer 14B.

  When the outer shape of each color cathode layer 14R, 14G, 14B is formed by patterning the conductive film, the etching included in the formation of the plasmonic structure is performed for each color cathode layer 14R, 14G, 14B. Etching may be used to form the outer shape.

  In the red plasmonic structure, a mask covering a part of the red cathode surface 4RS is formed on the red cathode surface 4RS, and the red cathode surface 4RS is etched using the mask. In the green plasmonic structure, a mask covering a part of the green cathode surface 4GS is formed on the green cathode surface 4GS, and the green cathode surface 4GS is etched using the mask. In the blue plasmonic structure, a mask covering a part of the blue cathode surface 4BS is formed on the blue cathode surface 4BS, and the blue cathode surface 4BS is etched using the mask.

  The mask applied to the red cathode surface 4RS has a periodic structure corresponding to the red plasmonic structure, and is a resist mask, a single particle film, or a laminate of a resist mask and a single particle film. It is preferable. The periodic structure corresponding to the plasmonic structure for red is a structure that covers only the protrusions in the plasmonic structure for red.

  The mask applied to the green cathode surface 4GS has a periodic structure corresponding to the green plasmonic structure, and this also includes a resist mask, a single particle film, and a laminate of a resist mask and a single particle film. Either is preferable. The periodic structure corresponding to the green plasmonic structure is a structure that covers only the protrusions in the green plasmonic structure.

  The mask applied to the blue cathode surface 4BS has a periodic structure corresponding to the plasmonic structure for blue, and this also includes a resist mask, a single particle film, and a laminate of a resist mask and a single particle film. Either is preferable. The periodic structure corresponding to the plasmonic structure for blue is a structure that covers only the protrusions in the plasmonic structure for blue.

  Whether the mask applied to the cathode surfaces 4RS, 4GS, and 4BS for each color is a resist mask, a single particle film, or a laminate of a resist mask and a single particle film is a color expressed by a pixel May be different for each pixel, or may be common to all pixels.

  In the manufacture of a mask using an optical device, the influence of disturbance factors such as vibration on the substrate 11, thermal contraction of the substrate 11, thermal expansion of the substrate 11, and fluctuation of the atmosphere increases as the period length of the step portion in the plasmonic structure becomes shorter. , Mask dimensional accuracy is low. Therefore, it is preferable that the single particle film is used as a mask rather than a resist mask as the period of the stepped portion in the plasmonic structure becomes shorter.

  When the masks applied to the cathode surfaces 4RS, 4GS, and 4BS for each color are all resist masks, the masks applied to the cathode surfaces 4RS, 4GS, and 4BS for each color may be formed at the same time. Alternatively, it may be formed for each color represented by a pixel.

  When the masks applied to the cathode surfaces 4RS, 4GS, 4BS for each color are all resist masks, the resist coating film formed on the cathode surfaces 4RS, 4GS, 4BS for each color is formed by a known lithography technique. Patterning may be performed, or patterning may be performed by a nanoimprint technique. At this time, the nanoimprint stamp used in the nanoimprint technology includes a stamp portion for forming a plasmonic structure for red, a stamp portion for forming a plasmonic structure for green, and a plasmonic structure for blue. One stamp may have a stamp portion for forming. With such a method using a nanoimprint stamp, it is possible to simultaneously form a resist mask on each color cathode surface 4RS, 4GS, 4BS.

  When the resist coating film formed on the cathode surfaces 4RS, 4GS, and 4BS for each color is patterned by the nanoimprint technique, the original nanoimprint stamp is formed by etching the original substrate using the single particle film as a mask. It is preferable. In the production of a mask using optical equipment, the shorter the period length of the step portion in the plasmonic structure, the more the disturbance factors such as vibration with respect to the original substrate, thermal contraction of the original substrate, thermal expansion of the original substrate, fluctuation of atmosphere, etc. The influence is large and the dimensional accuracy of the mask is low. Therefore, also in the preparation of the original nanoimprint stamp, the shorter the period length of the step portion in the plasmonic structure, the more preferable is the etching method using the single particle film as a mask rather than the resist mask.

  When the mask applied to the cathode surfaces 4RS, 4GS, and 4BS for each color is a single particle film, the Langmuir-Blodgett method (LB method), particle adsorption method, binder layer can be used as the method for forming the single particle film. A fixation method is used.

  In the LB method, a dispersion liquid in which particles are dispersed in a solvent having a specific gravity lower than that of water is used. First, the dispersion liquid is dropped onto the liquid surface of water. Next, the solvent is volatilized from the dispersion, whereby a single particle film made of particles is formed on the water surface. Then, the single particle film formed on the water surface is transferred to the cathode surfaces 4RS, 4GS, and 4BS for each color, thereby forming a mask made of the single particle film.

  In the particle adsorption method, first, the substrate 11 is immersed in a suspension of colloidal particles. Next, the second and higher particles are removed so that only the first particle layer electrostatically coupled to the cathode surfaces 4RS, 4GS, and 4BS for each color remains. As a result, a mask made of a single particle film is formed.

  In the binder layer fixing method, first, a binder layer is formed on the cathode surfaces 4RS, 4GS, and 4BS for each color, and a particle dispersion is applied onto the binder layer. Next, the binder layer is softened by heating, and only the first particle layer is embedded in the binder layer, and the second and higher particles are washed away. As a result, a mask made of a single particle film is formed.

  In the EL layer forming step S15, the red EL layer 15R is laminated on the red plasmonic structure. Further, the green EL layer 15G is stacked on the green plasmonic structure, and the blue EL layer 15B is stacked on the blue plasmonic structure.

  The method of forming the EL layer 15R for red, the method of forming the EL layer 15G for green, and the method of forming the EL layer 15B for blue are not particularly limited. A known film forming technique generally used for forming the EL layer is used.

  In the anode layer forming step S16, one anode layer 16 that covers each of the plurality of red EL layers 15R, the plurality of green EL layers 15G, and the plurality of blue EL layers 15B is formed. The method for forming the anode layer 16 is not particularly limited, and a known film forming technique generally used for forming the electrode layer, such as a sputtering method, is used.

As described above, according to the first embodiment, the effects listed below can be obtained.
(1) The red light output pixel 10R that emits red light has a red plasmonic structure having a red pitch 4CR. The wavelength of the plasmon light determined by the mode value of the red pitch 4CR is included in the wavelength band corresponding to the half width of the peak in the outgoing light spectrum of the red outgoing pixel 10R. The green light emitting pixel 10G that emits green light has a green plasmonic structure having a green pitch 4CG. The wavelength of the plasmon light determined by the mode value of the green pitch 4CG is included in the wavelength band corresponding to the half width of the peak in the light emission spectrum of the green light output pixel 10G. Therefore, the light extraction efficiency is improved in both the red light emission pixel 10R and the green light emission pixel 10G.

  (2) The blue light output pixel 10B that emits blue light has a blue plasmonic structure having a blue pitch 4CB. The wavelength of the plasmon light determined by the mode value of the blue pitch 4CB is included in the wavelength band corresponding to the half width of the peak in the outgoing light spectrum of the blue outgoing pixel 10B. Therefore, the light extraction efficiency is also increased in the blue light emitting pixel 10B.

  (3) The mode value of the green pitch 4CG is smaller than the mode value of the red pitch 4CR, and the blue pitch 4CB is smaller than the green pitch 4CG. Therefore, the light extraction efficiency is increased in each of the red light emission pixel 10R, the green light emission pixel 10G, and the blue light emission pixel 10B.

  (4) The red cathode layer 14R having a red plasmonic structure is located on the insulating layer 13 which is a flat surface. The processing for forming the red plasmonic structure is performed on the red cathode surface 4RS which is a flat surface. Therefore, it is easy to obtain the dimensional accuracy of the red pitch 4CR and the red step 4RH.

  (5) The green cathode layer 14G having a green plasmonic structure is positioned on the insulating layer 13 which is a flat surface. Then, the processing for forming the green plasmonic structure is performed on the green cathode surface 4GS which is a flat surface. Therefore, it is easy to obtain the dimensional accuracy of the green pitch 4CG and the green step 4GH.

  (6) The blue cathode layer 14B having a blue plasmonic structure is located on the insulating layer 13 which is a flat surface. Then, the processing for forming the blue plasmonic structure is performed on the blue cathode surface 4BS which is a flat surface. Therefore, it is easy to obtain the dimensional accuracy of the blue pitch 4CB and the blue step 4BH.

[Second Embodiment]
With reference to FIG. 5 and FIG. 6, a second embodiment in which the EL display device according to the present disclosure is embodied as an EL display device including light emitting layers for three different colors will be described. The EL display device according to the second embodiment is mainly different from the EL display device according to the first embodiment in the following points.

  That is, in the second embodiment, the interface between the red EL structure 30R and the insulating layer 13 has a fine concavo-convex structure to be formed on the red cathode surface as a red plasmonic structure. The interface between the green EL structure 30G and the insulating layer 13 has a fine concavo-convex structure to be formed on the green cathode surface as a green plasmonic structure. The interface between the blue EL structure 30G and the insulating layer 13 has a fine concavo-convex structure to be formed on the blue cathode surface as a blue plasmonic structure. Hereinafter, such a difference will be mainly described using the red light output pixel 10R, and description of the green light output pixel 10G and the blue light output pixel 10B having the same configuration as the red light output pixel 10R will be omitted.

  As shown in FIG. 5, the red light emission pixel 10R has a step surface 3RS on the insulating layer 13 as a boundary surface between the insulating layer 13 and the EL structure 30R. The step surface 3RS has a fine concavo-convex structure including a plurality of step portions for forming a red plasmonic structure. The upper part of the red cathode layer 14R constituting the EL structure 30R (4RS part in the figure: cathode part) and the interface shape of the EL layer 15R for red and the anode layer 16 follow the shape of the step surface 3RS. Have.

  The fine concavo-convex structure of the step surface 3RS is a periodic structure in which a plurality of step portions are repeated on the step surface 3RS, and functions as the fine concavo-convex structure C or the fine concavo-convex structure D. The periodic structure of the stepped surface 3RS may be a one-dimensional periodic structure in which a plurality of step portions are repeated along the one-dimensional direction, but is preferably a two-dimensional periodic structure in terms of increasing light extraction efficiency. .

  The step portion in the periodic structure of the step surface 3RS may be constituted by a plurality of protrusions protruding at the step surface 3RS, or may be constituted by a plurality of depressions recessed at the step surface 3RS. When the stepped portion in the periodic structure of the stepped surface 3RS is constituted by a protruding portion, the shape of the protruding portion is not particularly limited as long as it is a shape protruding at the stepped surface 3RS. For example, a conical shape, a cylindrical shape, A hemispherical shape, a pyramid shape, a prism shape, a truncated cone shape, a truncated pyramid shape, or a shape derived from one of these shapes may be used.

  When the stepped portion in the periodic structure of the stepped surface 3RS is constituted by a dent, the shape of the dent is not particularly limited as long as it is a shape recessed at the stepped surface 3RS. The shape of the dent may be, for example, a circular hole shape, a square hole shape, a circular hole shape whose diameter is reduced along the depth direction, or a square hole shape whose diameter is reduced along the depth direction.

  The red cathode layer 14R has a red cathode surface 4RS that constitutes an interface between the red EL layer 15R and the red cathode layer 14R. The red cathode surface 4RS has a red plasmonic structure.

  In the periodic structure of the step surface 3RS, the interval between the adjacent step portions is a red pitch 4CR. In the red plasmonic structure, the spacing between the adjacent stepped portions is also the red pitch 4CR. The mode value of the periodic length of the step portion of the red plasmonic structure is substantially equal to the mode value of the period length of the step portion of the periodic structure of the step surface 3RS.

  In plan view of the substrate 11, the step surface 3RS of the insulating layer 13 has a protrusion at a position where the red cathode layer 14R has a protrusion. The position where the step surface 3RS has a depression in the plan view of the substrate 11 is a position where the red cathode layer 14R has a depression. That is, the periodic structure of the step surface 3RS is transferred to the cathode surface 4RS, and the structure viewed from the plan view is made to follow the red plasmonic structure.

  In the periodic structure of the step surface 3RS, the average height, which is the average value of the heights of the steps, is the red base step 3RH. In the red plasmonic structure, the average height of the steps is the red step 4RH. The red step 4RH may be smaller than the red base step 3RH, or may be the same as the red base step 3RH.

  The red base step 3RH is preferably equal to or greater than the red step 4RH. If the red base level difference 3RH is greater than or equal to the red level difference 4RH, the level difference is difficult to fill even when the thickness of the layer stacked on the level difference surface 3RS is thick. Therefore, the red level difference required for the red plasmonic structure is required. A step 4RH is easily obtained.

  Note that the position where the green stepped surface has the protrusion in the plan view of the substrate 11 is the position where the green cathode layer 14G has the protrusion. The position where the stepped surface for green has a depression is the position where the cathode layer 14G for green has a depression. In the periodic structure of the stepped surface for green, the interval between adjacent stepped portions is a green pitch 4CG, and the most frequent pitch of the green pitch 4CG is larger than the most frequent pitch of the red pitch 4CR. small.

  Further, in the plan view of the substrate 11, the position where the blue step surface has the protrusion is the position where the blue cathode layer 14B has the protrusion. The position where the step surface for blue has a depression is the position where the cathode layer 14B for blue has a depression. In the periodic structure of the stepped surface for blue, the distance between adjacent stepped portions is a blue pitch 4CB, and the most frequent pitch of the blue pitch 4CB is larger than the most frequent pitch of the red pitch 4CR. It is small and smaller than the most frequent pitch of the green pitch 4CG.

[Method for Manufacturing EL Display Device]
As shown in FIG. 6, the EL display device manufacturing method includes a pixel circuit forming step S21, an insulating layer forming step S22, a periodic structure forming step S23, a cathode layer forming step S24, an EL layer forming step S25, and an anode layer forming step. Including S26.

  In the pixel circuit formation step S21, as in the first embodiment, a plurality of red pixel circuits 12R, a plurality of green pixel circuits 12G, and a plurality of blue pixel circuits 12B are formed on the substrate 11.

  In the insulating layer forming step S22, as in the first embodiment, the plurality of red pixel circuits 12R, the plurality of green pixel circuits 12G, and the plurality of blue pixel circuits 12B are entirely covered by one insulating layer 13. First, the insulating layer 13 is formed. Next, a plurality of contact holes communicating with each of the plurality of red pixel circuits 12R, each of the plurality of green pixel circuits 12G, and each of the plurality of blue pixel circuits 12B are provided in the insulating layer for each of the pixel circuits 12R, 12G, and 12B. 13 is formed.

  In the periodic structure forming step S23, a periodic structure for each pixel is formed on the upper surface of the insulating layer 13. That is, a mask that covers a portion corresponding to the red light emission pixel 10R on the upper surface of the insulating layer 13 is formed, and a periodic structure that is a fine uneven structure D for red is formed by etching the insulating layer 13 using the mask. Is done. Further, a mask that covers a portion corresponding to the green light output pixel 10G on the upper surface of the insulating layer 13 is formed, and etching of the insulating layer 13 using the mask also causes a period for green, which is also a fine concavo-convex structure D. A structure is formed. Further, a mask that covers a portion corresponding to the blue light emitting pixel 10B on the upper surface of the insulating layer 13 is formed, and etching of the insulating layer 13 using the mask results in a period for blue, which is also a fine concavo-convex structure D. A structure is formed.

  The formation of the periodic structure for the insulating layer 13 may be performed simultaneously with the formation of the contact hole described above. The etching included in the formation of the periodic structure may be etching for forming a contact hole. The mask used for forming the periodic structure may be formed integrally with the mask used for forming the contact hole. The periodic structure forming step S23 may be included as a part of the insulating layer forming step S22, and the periodic structure forming step S23 and the insulating layer forming step S22 may be different from each other.

  The mask applied to the formation of the periodic structure for the insulating layer 13 has a periodic structure corresponding to the above-described periodic structure (step surface 3RS, cathode surface 4RS) of the insulating layer 13, and includes a resist mask, a single particle It is preferably any of a laminate of a film, a resist mask and a single particle film. When the periodic structure forming step S23 is included as part of the insulating layer forming step S22, the mask applied to form the periodic structure for the insulating layer 13 is in addition to the periodic structure corresponding to the periodic structure of the insulating layer 13 described above. Thus, it has a structure corresponding to the opening shape of the contact hole. The above-described periodic structure corresponding to the periodic structure of the insulating layer 13 is a structure that covers only the protrusions in the periodic structure of the insulating layer 13. The structure corresponding to the opening shape of the contact hole is a structure that exposes only the portion that becomes the opening of the contact hole.

  Whether the mask applied to the insulating layer 13 is a resist mask, a single particle film, or a laminate of a resist mask and a single particle film may be different for each color represented by a pixel. , It may be common to all pixels. The shorter the period length of the stepped portion in the plasmonic structure, the more preferably the single particle film is used as the mask rather than the resist mask.

  When the mask applied to the insulating layer 13 is a resist mask for any pixel, the mask applied to the insulating layer 13 may be formed at the same time or for each color represented by the pixel. May be.

  When the mask applied to the insulating layer 13 is a resist mask for any pixel, the resist coating film formed on the insulating layer 13 may be patterned by a known lithography technique or a nanoimprint technique. May be patterned. At this time, the nanoimprint stamp used in the nanoimprint technology is to form a stamp portion for forming a red periodic structure, a stamp portion for forming a green periodic structure, and a blue periodic structure. May be included in one stamp. With such a method using a nanoimprint stamp, it is also possible to simultaneously form a nanoimprint mask in a region corresponding to each color light emitting pixel 10R, 10G, 10B.

  When the resist coating film formed on the insulating layer 13 is patterned by the nanoimprint technique, the nanoimprint stamp original plate is preferably formed by etching the original substrate using the single particle film as a mask. In the production of a nanoimprint stamp master, it is preferable that a single particle film is used as a mask.

When the mask to which the insulating layer 13 is applied is a single particle film, the LB method, particle adsorption method, and binder layer fixing method described above are used as the method for forming the single particle film.
In the cathode layer forming step S24, the cathode layer 14R, the material constituting the cathode layer is embedded in each of the plurality of contact holes and the cathode layer is independent for each of the pixel circuits 12R, 12G, 12B. 14G and 14B are formed. The method for forming the cathode layers 14R, 14G, and 14B for each color is not particularly limited, and a known electrode forming technique such as a film forming method or a patterning method is used.

  When the red cathode layer 14R is stacked on the red periodic structure formed on the insulating layer 13, the repetition of unevenness following the red periodic structure is self-aligned with the red cathode layer 14R. Formed. The red plasmonic structure is formed on the red cathode surface 4RS without any post-treatment such as etching applied to the red cathode layer 14R.

  In addition, in the green cathode layer 14G and the blue cathode layer 14B, similarly to the red cathode layer 14R, the cathode layer is not subjected to post-treatment such as etching, and the plasm for each color. A monic structure is formed.

  In the EL layer forming step S25, the red EL layer 15R is laminated on the red plasmonic structure. Further, the green EL layer 15G is stacked on the green plasmonic structure, and the blue EL layer 15B is stacked on the blue plasmonic structure. The method of forming the EL layer 15R for red, the EL layer 15G for green, and the EL layer 15B for blue is not particularly limited, and is a publicly known method generally used for forming an EL layer such as vacuum deposition or coating. The film forming technique is used.

  In the anode layer forming step S26, one anode layer 16 that covers each of the plurality of red EL layers 15R, the plurality of green EL layers 15G, and the plurality of blue EL layers 15B is formed. The method for forming the anode layer 16 is not particularly limited, and a known film forming technique generally used for forming the electrode layer, such as a sputtering method, is used.

As described above, according to the second embodiment, the effects listed below can be obtained.
(1) Each color cathode is applied to the cathode surface of each color cathode layer 14R, 14G, 14B without any post-treatment such as etching applied to the cathode surface of each color cathode layer 14R, 14G, 14B. A monic structure is formed. Therefore, damage due to post-processing such as etching is suppressed on the interfaces contacting the EL layers 15R, 15G, and 15B for the respective colors.

(2) Moreover, the restrictions from the processing surface are suppressed with respect to the cathode layers 14R, 14G, and 14B for each color.
(3) The average height of the step in the periodic structure of the insulating layer 13 is larger than the average height of the step in the plasmonic structure in the cathode layer 14. With such a configuration, the plasmonic effect is exhibited even when the thickness of the cathode layer stacked on the tip of the protrusion is thinner than the thickness of the cathode layer stacked on the bottom of the depression in the periodic structure of the insulating layer 13. Necessary steps can be easily obtained.

[Third Embodiment]
With reference to FIGS. 7 to 9, a third embodiment in which the EL display device according to the present disclosure is embodied as an EL display device including a light emitting layer for each color will be described. The EL display device according to the third embodiment is mainly different from the EL display device according to the first embodiment in the following points.

  That is, in the third embodiment, in the red EL structure 30R, the red anode layer 16R is sandwiched between the red EL layer 15R and the insulating layer 13, and the red anode layer 16R and A red EL layer 15 </ b> R is sandwiched between the cathode layer 14. Further, in the green EL structure 30G, a green anode layer is sandwiched between the green EL layer 15G and the insulating layer 13, and between the green anode layer and the cathode layer 14, A green EL layer 15G is sandwiched. Then, in the blue EL structure 30B, the blue anode layer is sandwiched between the blue EL layer 15B and the insulating layer 13, and between the blue anode layer and the cathode layer 14, A blue EL layer 15B is sandwiched. Hereinafter, such a difference will be mainly described using the red light output pixel 10R, and description of the green light output pixel 10G and the blue light output pixel 10B having the same configuration as the red light output pixel 10R will be omitted.

  As shown in FIG. 7, the red light emission pixel 10 </ b> R includes a red EL structure 30 </ b> R, and the EL structure 30 </ b> R includes a red anode layer 16 </ b> R, a red EL layer 15 </ b> R, and a cathode layer 14. It has. The red anode layer 16R is stacked on the red driving unit 20R through the insulating layer 13, and the red driving unit 20R supplies a driving current to the red anode layer 16R. The cathode layer 14 is an electrode common to the green light output pixel 10G and the blue light output pixel 10B, and is connected to an external power supply line other than the red light output pixel 10R.

  The red light emission pixel 10R has a red anode surface 6RS on a red anode layer 16R which is an example of a lower electrode layer as a boundary surface between the red anode layer 16R and the red EL layer 15R. The red anode surface 6RS has a fine concavo-convex structure A composed of stepped portions for forming a red plasmonic structure. A portion of the cathode layer 14 corresponding to the red light emission pixel 10R has a shape that follows the shape of the red anode surface 6RS.

  The fine concavo-convex structure A of the red anode surface 6RS is a periodic structure in which a plurality of step portions are repeated on the red anode surface 6RS. The periodic structure of the red anode surface 6RS may be a one-dimensional concavo-convex structure in which a plurality of steps are repeated along the one-dimensional direction, but is a two-dimensional periodic structure in that the light extraction efficiency is increased. Is preferred.

  The step portion in the periodic structure of the red anode surface 6RS may be constituted by a plurality of protrusions protruding from the red anode surface 6RS, or by a plurality of depressions recessed in the red anode surface 6RS. It may be configured. When the stepped portion in the periodic structure of the red anode surface 6RS is constituted by a protrusion, the shape of the protrusion is not particularly limited as long as it is a shape protruding from the red anode surface 6RS. The shape may be a conical shape, a cylindrical shape, a hemispherical shape, a pyramid shape, a prism shape, a truncated cone shape, a truncated pyramid shape, or a shape derived from one of these.

  When the stepped portion in the periodic structure of the red anode surface 6RS is constituted by a depression, the shape of the depression is not particularly limited as long as the depression is recessed at the red anode face 6RS. The shape of the dent may be, for example, a circular hole shape, a square hole shape, a circular hole shape whose diameter is reduced along the depth direction, or a square hole shape whose diameter is reduced along the depth direction.

  The red EL layer 15R includes a red light emitting layer. The red light emitting layer has a shape that follows the shape of the red anode surface 6RS. In the plan view of the substrate 11, the position where the red EL layer 15R has a protrusion is the position where the red anode layer 16R has a protrusion. In the plan view of the substrate 11, the position where the red EL layer 15R has a depression is the position where the red anode layer 16R has a depression. That is, the periodic structure of the anode surface 6RS for red follows the step structure in the EL layer 15R for red for the structure seen from the plan view direction.

  The cathode layer 14 has a red cathode surface 4RS constituting the interface between the red EL layer 15R and the cathode layer 14 as an example of the upper electrode layer as a lower surface. The red cathode surface 4RS has a red plasmonic structure which is a fine uneven structure B having a shape following the shape of the red anode surface 6RS which is an example of the lower electrode layer.

  In the periodic structure of the red anode surface 6RS, the interval between the adjacent step portions is a red pitch 4CR. In the red plasmonic structure, the spacing between the adjacent stepped portions is also the red pitch 4CR. The periodic length between the step portions of the red plasmonic structure is substantially equal to the periodic length between the step portions of the periodic structure of the red anode surface 6RS.

  In the plan view of the substrate 11, the position where the red anode surface 6RS has a protrusion is the position where the red cathode layer 14R has a depression. In the plan view of the substrate 11, the position where the red anode surface 6RS has a depression is the position where the red cathode layer 14R has a protrusion. That is, the periodic structure of the red anode surface 6RS causes the structure viewed from the plan view to follow the red plasmonic structure.

  In the periodic structure of the anode surface 6RS for red, the average height of each step is the anode step 6RH. In the red plasmonic structure, the average height of each step is the red step 4RH. The red step 4RH may be smaller than the anode step 6RH or the same as the anode step 6RH.

  The anode step 6RH is preferably larger than the red step 4RH. If the anode step 6RH is larger than the red step 4RH, the step is difficult to fill even when the thickness of the layer stacked on the red anode surface 6RS is thick. Therefore, the red color required for the red plasmonic structure It is easy to obtain the step 4RH for use.

  Note that the position where the green anode surface has a protrusion in the plan view of the substrate 11 is the position where the green cathode layer 14G has a depression. The position where the green anode surface has a depression is the position where the green cathode layer 14G has a protrusion. In the periodic structure of the green anode surface, the interval between adjacent stepped portions is a green pitch 4CG, which is smaller than the red pitch 4CR.

  Further, in the plan view of the substrate 11, the position where the blue anode surface has the protrusion is the position where the blue cathode layer 14B has a depression. The position where the blue anode surface has a depression is the position where the blue cathode layer 14B has a protrusion. In the periodic structure of the blue anode surface, the interval between adjacent stepped portions is the blue pitch 4CB, which is smaller than the red pitch 4CR and smaller than the green pitch 4CG.

[Method for Manufacturing EL Display Device]
As shown in FIG. 8, the EL display device manufacturing method includes a pixel circuit forming step S31, an insulating layer forming step S32, an anode layer forming step S33, a periodic structure forming step S34, an EL layer forming step S35, and a cathode layer forming step. S36 is included.

  In the pixel circuit formation step S31, as in the first embodiment, a plurality of red pixel circuits 12R, a plurality of green pixel circuits 12G, and a plurality of blue pixel circuits 12B are formed on the substrate 11.

  In the insulating layer forming step S32, as in the first embodiment, the plurality of red pixel circuits 12R, the plurality of green pixel circuits 12G, and the plurality of blue pixel circuits 12B are entirely covered by one insulating layer 13. First, the insulating layer 13 is formed. Next, a plurality of contact holes communicating with each of the plurality of red pixel circuits 12R, each of the plurality of green pixel circuits 12G, and each of the plurality of blue pixel circuits 12B are provided in the insulating layer for each of the pixel circuits 12R, 12G, and 12B. 13 is formed.

  In the anode layer forming step S33, the material constituting the anode layer is embedded in each of the plurality of contact holes, and the anode layer is independent for each of the pixel circuits 12R, 12G, and 12B. A layer is formed. The method for forming the anode layer for each color is not particularly limited, and a known electrode forming technique such as a film forming method or a patterning method is used.

In the periodic structure forming step S34, a periodic structure for each color is formed as the fine concavo-convex structure A on the anode surface of the anode layer for each color.
The mask applied to the anode layer for each color has a periodic structure corresponding to the plasmonic structure that emphasizes the wavelength range for each color, and includes a resist mask, a single particle film, and a laminate of the resist mask and the single particle film. Either is preferable. When the periodic structure forming step S34 is included as part of the anode layer forming step S33, the mask applied to the anode surface for each color is for each color in addition to the periodic structure corresponding to the plasmonic structure for each color. It has a structure corresponding to the outer shape of the anode surface. The periodic structure corresponding to the plasmonic structure for each color is a structure that covers only the depressions in the plasmonic structure for each color. The structure corresponding to the outer shape of the anode surface for each color is a structure that covers only the portion that becomes the anode surface for each color.

  Whether the mask applied to the anode surface for each color is a resist mask, a single particle film, or a laminate of a resist mask and a single particle film may differ depending on the color represented by the pixel. It may be common to all pixels.

  In the EL layer forming step S35, the red EL layer 15R is laminated on the periodic structure of the red anode surface 6RS. Further, the green EL layer 15G is stacked on the periodic structure of the green anode surface, and the blue EL layer 15B is stacked on the periodic structure of the blue anode surface. The method of forming the EL layer 15R for red, the method of forming the EL layer 15G for green, and the method of forming the EL layer 15B for blue are not particularly limited. A known film forming technique generally used for forming the EL layer is used.

  In the cathode layer forming step S36. One cathode layer 14 that covers each of the plurality of red EL layers 15R, the plurality of green EL layers 15G, and the plurality of blue EL layers 15B is formed. The method for forming the cathode layer 14 is not particularly limited, and a known film forming technique generally used for forming the electrode layer, such as a sputtering method, is used. As a result, a red plasmonic structure is formed as the fine concavo-convex structure B at the interface between the red EL layer 15 </ b> R and the cathode layer 14. In addition, a green plasmonic structure is formed as the fine concavo-convex structure B at the interface between the green EL layer 15 </ b> G and the cathode layer 14. Then, a blue plasmonic structure is formed as the fine concavo-convex structure B at the interface between the blue EL layer 15 </ b> B and the cathode layer 14.

As described above, according to the third embodiment, the effects listed below can be obtained.
(1) The EL layers 15R, 15G, and 15B for each color are stacked on the periodic structure corresponding to the plasmonic structure for each color. A plasmonic structure is formed on the upper surface of each color EL layer 15R, 15G, 15B. Therefore, a plasmonic structure is formed without performing post-processing such as etching on the EL layers 15R, 15G, and 15B that are susceptible to thermal damage and chemical damage.

  (2) The average height of the step (6RS) in the periodic structure of the anode layer is larger than the average height of the step (4RS) of the plasmonic structure. With such a configuration, the step required for the plasmonic structure is easily obtained by the periodic structure of the anode layer.

Note that the third embodiment can be implemented with the following modifications.
As shown in FIG. 9, the anode layer 16R for red, the anode layer 16G for green, and the anode layer 16B for blue are located on the upper surface of the insulating layer 13 with a gap therebetween. . The upper surface of the red anode layer 16R is a red anode surface 6RS having a periodic structure for forming a red plasmonic structure. The upper surface of the green anode layer 16G is a green anode surface 6GS having a periodic structure for forming a green plasmonic structure. The upper surface of the blue anode layer 16B is a blue anode surface 6BS having a periodic structure for forming a blue plasmonic structure.

  On the upper surface of the insulating layer 13, a plurality of inter-anodic insulating layers 17 configured to fill these gaps are positioned between adjacent anode layers. For example, between the red anode layer 16R and the green anode layer 16G, an inter-anode insulating layer 17 configured to fill these gaps is located. Between the green anode layer 16G and the blue anode layer 16B, an inter-anode insulating layer 17 configured to fill these gaps is located. Between the red anode layer 16R and the blue anode layer 16G, an inter-anode insulating layer 17 configured to fill these gaps is located.

  Each of the plurality of inter-anodic insulating layers 17 has an inter-anodic slope 17S connected to the anode surfaces 6RS, 6GS, 6BS with respect to the anode layer adjacent to the inter-anodic insulating layer 17. For example, one inter-anode slope 17S is connected to one red anode surface 6RS. One inter-anode slope 17S is connected to one green anode surface 6GS. One inter-anode slope 17S is connected to one blue anode surface 6BS. Each of the plurality of inter-anode slopes 17S is configured so that the upper side of the anode surfaces 6RS, 6GS, 6BS for each color is widened, and extends obliquely upward from the anode surface connected thereto.

  The inter-anode slope 17S connected to the red anode surface 6RS has a periodic structure composed of stepped portions for forming a red plasmonic structure, like the red anode surface 6RS. The inter-anode slope 17S connected to the green anode surface 6GS has a periodic structure including stepped portions for forming a green plasmonic structure, like the green anode surface 6GS. The inter-anode slope 17S connected to the blue anode surface 6BS has a periodic structure including stepped portions for forming a blue plasmonic structure, like the blue anode surface 6RS.

  According to such a configuration, the range in which the plasmonic structure is formed is wider than the configuration in which the periodic structure for forming the plasmonic structure is formed only on the anode surfaces 6RS, 6GS, and 6BS for each color. . Therefore, the light extraction efficiency is further increased.

  As with the cathode layers 14R, 14G, and 14B of the second embodiment, the periodic structure of the anode layers 16R, 16G, and 16B for each color is a periodic structure (fine concavo-convex structure D) formed on the upper surface of the insulating layer 13. The structure which follows may be sufficient. That is, a periodic structure for forming a plasmonic structure is formed on the upper surface of the insulating layer 13 in a portion corresponding to each of the color emitting pixels 10R, 10G, and 10B, and for each color on the periodic structure of the insulating layer 13. The anode layers 16R, 16G, and 16B may be positioned.

[Fourth Embodiment]
With reference to FIG. 10, a fourth embodiment in which the EL display device according to the present disclosure is embodied as an EL display device including a white light emitting layer will be described. The EL display device according to the fourth embodiment is mainly different from the EL display device according to the first embodiment in the following points. That is, in the EL display device according to the fourth embodiment, the red light emitting pixel, the green light emitting pixel, and the blue light emitting pixel each include a light emitting layer for white. In the following, such differences will be mainly described, and description of the same configuration as that of the first embodiment will be omitted.

  As shown in FIG. 10, the cathode surface 4RS in the red light emission pixel 10R has a red plasmonic structure, as in the first embodiment. The cathode surface 4GS in the green light emitting pixel 10G has a plasmonic structure for green as in the first embodiment. The cathode surface 4BS in the blue light emitting pixel 10B has a plasmonic structure for blue as in the first embodiment. The red light emitting pixel 10R, the green light emitting pixel 10G, and the blue light emitting pixel 10B each have a white light emitting layer that generates white light as a common light emitting layer.

  The red light output pixel 10R includes a red color filter 25R that converts white light into red light as an example of a color filter. The green light output pixel 10G includes a green color filter 25G that converts white light into green light as an example of a color filter. The blue light output pixel 10B includes a blue color filter 25B that converts white light into blue light as an example of a color filter.

  The red light emission pixel 10R converts surface plasmons generated when red light is generated from white light generated by the white light emitting layer into red radiation light by a red plasmonic structure, and enhances red light. The white light thus converted is finally converted into red light by the red color filter 25R and emitted. That is, the red light output pixel 10R emphasizes red light among white light generated by the white light emitting layer, and sets the light emission color to red.

  The green light emitting pixel 10G converts the surface plasmon generated when the green light is generated out of the white light generated by the white light emitting layer into green radiant light by the green plasmonic structure, thereby enhancing the green color. The resulting white light is finally converted into green light by the green color filter 25G and emitted. That is, the green light output pixel 10G emphasizes green light among white light generated by the white light emitting layer, and sets the light output color to green.

  The blue light output pixel 10B converts surface plasmon generated when generating blue light out of white light generated by the white light emitting layer into blue radiation light by a blue plasmonic structure, and enhances blue light. The resulting white light is finally converted into blue light by the blue color filter 25B and emitted. That is, the blue light output pixel 10B emphasizes blue light among the white light generated by the white light emitting layer and sets the light emission color to blue.

As described above, according to the fourth embodiment, the following effects can be obtained.
(1) With the above-described configuration, the light emitting layer can be shared in the red light emitting pixel 10R, the green light emitting pixel 10G, and the blue light emitting pixel 10B. Light corresponding to the color represented by each pixel 10R, 10G, 10B is radiated.

Note that the fourth embodiment can be implemented with the following modifications.
As with the cathode layers 14R, 14G, and 14B of the second embodiment, the periodic structure of the cathode layers 14R, 14G, and 14B for each color is a periodic structure (fine uneven structure D) formed on the upper surface of the insulating layer 13. The structure which follows may be sufficient. That is, a periodic structure for forming a plasmonic structure is formed on the upper surface of the insulating layer 13 in a portion corresponding to each of the color emitting pixels 10R, 10G, and 10B, and for each color on the periodic structure of the insulating layer 13. The cathode layers 14R, 14G, and 14B may be positioned.

  As in the third embodiment, anode layers 16R, 16G, and 16B for the respective colors are formed on the insulating layer 13, and one common cathode layer is formed on the EL layers 15R, 15G, and 15B for the respective colors. 14 may be formed. The plasmonic structure of the cathode layer 14 may follow the periodic structure of the anode layers 16R, 16G, and 16B for each color.

[Fifth Embodiment]
With reference to FIG. 11, a fifth embodiment in which the EL display device according to the present disclosure is embodied as an EL display device including white light-emitting pixels will be described. The EL display device according to the fifth embodiment is mainly different from the EL display device according to the fourth embodiment in the following points. That is, the EL display device according to the fifth embodiment includes a white light emitting pixel that emits white light in addition to a red light emitting pixel, a green light emitting pixel, and a blue light emitting pixel. Hereinafter, such differences will be mainly described, and the description of the same configuration as that of the fourth embodiment will be omitted.

  As shown in FIG. 11, the EL display device includes a white light output pixel 10W that emits white light. The white light output pixel 10W includes a white pixel circuit 12W that supplies a drive current for causing the white light output pixel 10W to emit light. The white pixel circuit 12W is covered with the insulating layer 13 in the same manner as the other color pixel circuits 12R, 12G, and 12B.

  The white light output pixel 10W includes a white cathode layer 14W, a white EL layer 15W, and an anode layer 16 common to the other color light output pixels 10R, 10G, and 10B. The white cathode layer 14W is connected to the white pixel circuit 12W through the insulating layer 13, and the white pixel circuit 12W supplies a drive current to the white cathode layer 14W. When a current flows between the anode layer 16 and the white cathode layer 14W, holes are injected from the anode layer 16 into the white EL layer 15W, and the white cathode layer 14W to the white EL layer 15W. Electrons are injected into the. The white EL layer 15W generates white light by the combination of holes and electrons injected into the white EL layer 15W.

  The white cathode layer 14W may have a function of reflecting white light or a function of transmitting white light, like the cathode layers 14R, 14G, and 14G for other colors. Good. When the white cathode layer 14W has a function of reflecting white light, the anode layer 16 has a light transmitting property of transmitting white light, and the EL display device functions as a top emission type. When the white cathode layer 14W has a function of transmitting white light, the anode layer 16 has light reflectivity for reflecting white light, and the EL display device functions as a bottom emission type.

  The white cathode layer 14W has a white cathode surface 4WS that forms an interface between the white EL layer 15W and the white cathode layer 14W. The white cathode surface 4WS has a fine concavo-convex structure for white composed of a plurality of stepped portions that are repeated along the extending direction of the cathode surface 4WS. The fine concavo-convex structure for white is a plasmonic structure, and the stepped portion in the plasmonic structure for white may be constituted by a plurality of protrusions protruding from the white cathode surface 4WS, or a white cathode You may be comprised by the several hollow hollowed in the surface 4WS.

  When the step portion in the white plasmonic structure is constituted by a protrusion, the shape of the protrusion is not particularly limited as long as the shape protrudes from the white cathode surface 4WS. It may be a shape, a hemispherical shape, a pyramid shape, a prism shape, a truncated cone shape, a truncated pyramid shape, or a shape derived from one of these.

  When the stepped portion in the white plasmonic structure is constituted by a dent, the shape of the dent is not particularly limited as long as the shape is a dent on the white cathode surface 4WS. The shape of the dent is, for example, a circular hole shape, a square hole shape, a circular hole shape expanded in the depth direction, a circular hole shape reduced in the depth direction, or a diameter expanded in the depth direction. It may be a square hole shape or a square hole shape whose diameter is reduced along the depth direction.

  In the white plasmonic structure, the stepped portions on the white cathode surface 4WS are randomly positioned on the cathode surface 4WS. In addition, the state located at random shows the state where the space | interval between the centers of a level | step-difference part and the direction where a level | step-difference part is located are not constant. In the white plasmonic structure, the stepped portions are randomly positioned in two dimensions, so that when the white EL layer 15W emits light, light over the entire wavelength band from which the white light emitting pixels emit light is efficiently extracted. In the white plasmonic structure, the interval between adjacent step portions is a white pitch, and the average height of each step is a white step. In the white plasmonic structure, the white pitch is a distance between adjacent step portions. In addition, it is preferable that the level | step difference for white is 15 to 70 nm, and it is more preferable that it is 20 to 40 nm. In the white plasmonic structure, when the white step is less than 15 nm, it is difficult to obtain sufficient light extraction efficiency. Further, if the step for white exceeds 150 nm, the EL layer is likely to be short-circuited at an excessively thin portion.

  When the white light emitting layer generates light, near-field light is generated in the vicinity of the white light emitting layer. The distance between the white light emitting layer and the white cathode layer 14W is so short that near-field light is generated on the white cathode surface 4WS. Field light is converted to surface plasmons. The surface plasmon converted by the white cathode surface 4WS is extracted as white radiant light having a wide range of emission wavelengths.

  The red light output pixel 10R includes a red color filter 25R that converts white light into red light, and the green light output pixel 10G includes a green color filter 25G that converts white light into green light. . The blue light output pixel 10B includes a blue color filter 25B that converts white light into blue light. On the other hand, the white light output pixel 10 </ b> W includes a white transmission layer 25 </ b> W that transmits white light.

As described above, according to the fifth embodiment, the following effects can be obtained.
(1) In addition to the red light output pixel 10R, the green light output pixel 10G, and the blue light output pixel 10B, the white light output pixel 10W also emits light corresponding to the color to be expressed.

Note that the fifth embodiment can be implemented with the following modifications.
As with the cathode layers 14R, 14G, and 14B of the second embodiment, the plasmonic structure that the white cathode layer 14W has is a structure that follows the fine concavo-convex structure C formed on the upper surface of the insulating layer 13. Good. That is, a fine concavo-convex structure C for forming a plasmonic structure for white is formed on a portion of the upper surface of the insulating layer 13 corresponding to the white light output pixel 10 </ b> W, and on the fine concavo-convex structure C of the insulating layer 13. The white cathode layer 14W may be positioned.

  As in the third embodiment, a white anode layer is formed on the insulating layer 13, and one cathode layer 14 that is common to other light emitting pixels is formed on the white EL layer 15 </ b> W. May be. The plasmonic structure of the cathode layer 14 may follow the fine concavo-convex structure A of the anode layer for each color.

An example of each layer constituting the EL display device of each of the above embodiments will be described below.
[Substrate 11]
The material constituting the substrate 11 may be an inorganic material, an organic material, or a combination thereof. When the material constituting the substrate 11 is an inorganic material, the inorganic material is, for example, various types of glass such as quartz glass, non-alkali glass, and white glass, and transparent inorganic favorite materials such as mica. When the material constituting the substrate 11 is an organic material, the organic material is, for example, a resin film such as a cycloolefin film or a polyester film, or a fiber in which fine fibers such as cellulose nanofiber are mixed in the resin film. Reinforced plastic material.

  When the EL display device is a bottom emission type, the visible light transmittance of the substrate 11 is preferably higher, and the transmittance is preferably 70% or more with respect to the visible light range of 380 nm to 800 nm. 80 or more, more preferably 90% or more.

[Pixel circuits 12R, 12G, 12B, 12W]
Each color pixel circuit 12R, 12G, 12B, 12W is not particularly limited as long as it is a circuit that supplies a drive current, and a known circuit can be used. Each of the color pixel circuits 12R, 12G, 12B, and 12W may be a circuit that supplies an externally generated drive current to a connection destination EL structure. Alternatively, each of the color pixel circuits 12R, 12G, 12B, and 12W may be a circuit that generates a drive current by itself and supplies the drive current.

  In a configuration in which each color pixel circuit 12R, 12G, 12B, 12W generates its own drive current, each color pixel circuit 12R, 12G, 12B, 12W includes, for example, a thin film transistor, a power supply line that supplies power to the thin film transistor, Including control lines for controlling driving. In the configuration in which the drive current is generated outside the color pixel circuits 12R, 12G, 12B, and 12W, the color pixel circuits 12R, 12G, 12B, and 12W omit the thin film transistors, the power supply lines, the control lines, and supply the drive current. It may be configured only from the current supply line.

[Insulating layer 13]
-The material which comprises the insulating layer 13 will not be specifically limited if it is a material which can electrically insulate between each color pixel circuit 12R, 12G, 12B, 12W and the EL structure corresponding to it. The material constituting the insulating layer 13 may be an inorganic material, an organic material, or a combination thereof. When the material constituting the insulating layer 13 is an inorganic material, the inorganic material is, for example, silicon oxide or silicon nitride. When the material constituting the insulating layer 13 is an organic material, the organic material is, for example, a positive resist material or a negative resist material.

[Cathode layers 14, 14R, 14G, 14B, 14W]
When the cathode layers 14R, 14G, 14B, and 14W for each color are electrodes that transmit visible light, the transparent conductive material is not particularly limited, and a known material can be used as the transparent conductive material. For example, transparent conductive materials that transmit visible light are indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (Zinc Oxide (ZnO)), It is one selected from the group consisting of zinc-tin oxide (ZTO).

  The cathode layers 14R, 14G, 14B, and 14W for each color are electrodes that reflect visible light. When the cathode layers 14R, 14G, 14B, and 14W are composed of one layer, the material that reflects visible light is silver, such as a silver magnesium alloy. It is preferable that it is any one of the group which consists of an alloy whose content rate is 70 mass% or more, aluminum, and silver. When the cathode layers 14R, 14G, 14B, and 14W for each color include a layer that transmits visible light and a reflective layer, the transparent conductive material that transmits visible light is not particularly limited, and is known as a transparent conductive material. Materials can be used. The reflective layer is preferably one of a group consisting of an alloy having a silver content of 70% by mass or more, aluminum, and silver, such as a silver magnesium alloy.

The thickness of each color cathode layer 14R, 14G, 14B, 14W is preferably 50 nm to 3000 nm.
[Anode layer 16, 16R, 16G, 16B]
-When anode layer 16, 16R, 16G, 16B is an electrode which permeate | transmits visible light, a transparent conductive material is not specifically limited, A well-known material can be used as a transparent conductive material. For example, transparent conductive materials that transmit visible light are indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (Zinc Oxide (ZnO)), It is one selected from the group consisting of zinc-tin oxide (ZTO).

  The anode layers 16, 16R, 16G, and 16B are electrodes that reflect visible light. When the anode layers 16, 16R, 16G, and 16B are formed of one layer, the material that reflects visible light is preferably silver or aluminum. When the anode layer 16 includes a layer that transmits visible light and a reflective layer, the transparent conductive material that transmits visible light is not particularly limited, and a known material can be used as the transparent conductive material. The reflective layer is preferably silver or aluminum.

The thickness of the anode layer 16 is preferably 50 nm to 3000 nm.
[Layer structure of EL layer]
The at least one EL layer selected from the group consisting of the red EL layer 15R, the green EL layer 15G, the blue EL layer 15B, and the white EL layer 15W may have the following multilayer structure. preferable. That is, the EL layer preferably includes a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer in addition to the light emitting layer. In the hole injection layer, holes are injected from the anode layer. The hole transport layer transports holes from the hole injection layer to the light emitting layer and blocks electrons entering from the light emitting layer. The electron injection layer is injected with electrons from the cathode layer. The electron transport layer transports electrons from the electron injection layer to the light emitting layer and blocks holes entering from the light emitting layer.

  The hole injection layer, the hole transport layer, the light emitting layer, the electron transport layer, and the electron injection layer may have one function, or at least one layer is omitted, and other than the omitted layers Other layers may also serve two functions.

  Each of the EL layer 15R for red, the EL layer 15G for green, the EL layer 15B for blue, and the EL layer 15W for white includes at least a light emitting material that emits a color corresponding to each layer. Any layer including a light emitting layer may be used. The red EL layer 15R may be composed of only the red light emitting layer, and the green EL layer 15G may be composed of only the green light emitting layer. The blue EL layer 15B may be composed only of the blue light emitting layer, and the white EL layer 15W may be composed only of the white light emitting layer. The light emitting layer is the most important layer in the EL structure when the pixel emits light of the color corresponding to the pixel, and other layers other than the light emitting layer may be omitted.

  The light emitting layer in the white EL layer 15W is formed of a mixture of a material that constitutes the red light emitting layer, a material that constitutes the green light emitting layer, and a material that constitutes the blue light emitting layer. It may be a single layer. Alternatively, the light emitting layer in the white EL layer 15W may be a multilayer body formed of a plurality of layers formed of materials having different colors of emitted light. For example, the light emitting layer in the white EL layer 15W may be a multilayer body including a red light emitting layer, a green light emitting layer, and a blue light emitting layer.

[Formation material of EL layer]
The material constituting the EL layer 15R for red, the EL layer 15G for green, the EL layer 15B for blue, and the EL layer 15W for white may be an organic material or an inorganic material Also good. The organic material forming the light-emitting layer may be a material in which a fluorescent dye compound or a phosphorescent material is added to another substance that is a host material. The host material is preferably a material constituting the hole transport layer or a material constituting the electron transport layer. The materials constituting the red EL layer 15R, the green EL layer 15G, the blue EL layer 15B, and the white EL layer 15W are not particularly limited, and known materials are used.

  The material constituting the light emitting layer in the white EL layer 15W may be a mixture of materials having different colors of emitted light. For example, the light emitting layer in the white EL layer 15W is a mixture of a material constituting the red light emitting layer, a material constituting the green light emitting layer, and a material constituting the blue light emitting layer. May be.

  The low molecular weight organic substance that forms the red light emitting layer is, for example, 4- (Dicyanomethylene) -2-methyl-6-julolidyl-9-enyl-4H-pyran, (5,6,11,12)- Tetraphenylnaphthacene, Bis [1- (9,9-dimethyl-9H-fluoren-2-yl) -isoquinoline] (acetylacetonate) iridium (III).

  -Low molecular organic substances that form a green light-emitting layer are, for example, Tris (2-phenylpyridine) iridium (III), Tris [2- (p-tolyl) pyridine] iridium (III), 9,10-Bis [phenyl (m-tolyl) -amino] anthracene.

  -Low molecular organic substances that form a light emitting layer for blue are, for example, Perylene, 1,4-Bis [2- (3-N-ethylcarbazoryl) vinyl] benzene, 4- (Di-p-tolylamino) -4 '-[(di-p-tolylamino) styryl] stilbene, 4,4'-Bis [4- (diphenylamino) styryl] biphenyl.

[Pixel colors]
The pixel may further include a color filter that receives light other than white and adjusts the color of the light. For example, the red light output pixel 10R may include a color filter that receives red light and further narrows the wavelength band of the light color in the red band, and the green light output pixel 10G receives green light. A color filter that further narrows the wavelength band of the light color in the green band may be provided. The blue light output pixel 10B may include a color filter that receives blue light and further narrows the wavelength band of the light color in the blue band. At this time, the red light emitting pixel 10R may include a color filter that converts the light generated by the white light emitting layer into red light, and the green light emitting pixel 10G is generated by the white light emitting layer. You may provide the color filter which converts light into green light. The blue light output pixel 10B may include a color filter that converts light generated by the white light emitting layer into blue light.

[Pixel shape and arrangement]
The shape of each color light output pixel viewed from the light extraction surface is not particularly limited, and may be, for example, a rectangular shape or a polygonal shape other than a rectangular shape. The size of each color outgoing pixel viewed from the light extraction surface is not particularly limited, and for example, the red outgoing pixel 10R, the green outgoing pixel 10G, and the blue outgoing pixel 10B may have the same size. Alternatively, the red light output pixel 10R may be larger than the green light output pixel 10G, and the blue light output pixel 10B may be larger than the green light output pixel 10G. The shape of each color output pixel viewed from the light extraction surface and the size of each color output pixel viewed from the light extraction surface are the type of EL display device, the resolution required for the EL display device, and the manufacture of the EL display device. It is set as appropriate according to the restrictions caused by the method.

  The arrangement of the pixels viewed from the light extraction surface is not particularly limited. For example, one pixel column is configured from pixels arranged on one straight line, and along a direction intersecting with the extending direction of the pixel column, A plurality of pixel columns may be repeated. Alternatively, one pixel group may be configured from the red light output pixel 10R, the green light output pixel 10G, and the blue light output pixel 10B, and a plurality of pixel groups may be arranged on one straight line. Further, one pixel group may be configured from the red light output pixel 10R, the green light output pixel 10G, the blue light output pixel 10B, and the white light output pixel 10W, and a plurality of pixel groups may be arranged on one straight line.

  The arrangement of the pixels in the pixel row is not particularly limited, and may be repeated in the order of the red light emission pixel 10R, the green light emission pixel 10G, and the blue light emission pixel 10B, or the red light emission pixel 10R, the blue light emission pixel 10B, and the green light emission light. It may be repeated in the order of the pixel 10G. The arrangement of the pixels in the pixel group is not particularly limited, and the pixels may be arranged on a straight line, or the pixels may be arranged at the vertices of a polygon. For example, it may be a simple matrix in which pixels having the same rectangular shape are arranged along the two-dimensional direction, or pixels having different sizes for each color to be expressed are arranged along the two-dimensional direction. It may be a pen tile matrix that enhances the expression of white. The arrangement of the pixels as viewed from the light extraction surface is appropriately set according to the type of the EL display device, the resolution required for the EL display device, restrictions due to the manufacturing method of the EL display device, and the like.

The above embodiments can be implemented with the following modifications.
A part of the wavelength of the emitted light may overlap each other in each of the pixels that emit different light emission colors. It is most important that the wavelength bands corresponding to the half width of the peak in the light emission spectrum are different from each other in each pixel that emits different light emission colors, and the emitted light may not have a wavelength that overlaps each other. . In short, the most frequent pitch of the plasmonic structure in each of the plurality of pixels is a size that excites plasmon light, and the wavelength of the plasmon light is in a wavelength band corresponding to the half-value width at the peak of the emission spectrum. Any configuration may be included. And the period length in a plasmonic structure should just be so small that the wavelength band corresponding to a half value width is located in the short wavelength side. In each of the plurality of pixels, the interval between the adjacent stepped portions may be small as the half-wavelength wavelength band in the light emission spectrum is positioned on the short wavelength side.

  When the plurality of pixels provided in the EL display device emit three or more different colors, the mode pitch of the plasmonic structure is a size that excites plasmon light in at least two pixels that emit two different colors. And the wavelength of the plasmon light may be included in the wavelength band corresponding to the half width at the peak of the light emission spectrum. And the space | interval between mutually adjacent level | step-difference parts should just be so small that the wavelength band of emitted light is located in the short wavelength side. In the EL display device, it is most important that the wavelength of the plasmon light is included in a wavelength band corresponding to the half-value width in pixels that emit two different colors, and in pixels that emit colors other than two colors, The plasmonic structure itself may be omitted. The EL display device may include a configuration in which the intervals between adjacent step portions are equal between pixels having different wavelength bands of light emission colors. In addition, the EL display device may include a configuration in which a pixel in which the wavelength band of the light emission color is located on the short wavelength side has a larger interval between the adjacent stepped portions.

  S11, S21, S31 ... Pixel circuit forming step, S12, S22, S32 ... Insulating layer forming step, S13, S24, S36 ... Cathode layer forming step, S14 ... Plasmonic structure forming step, S15, S25, S35 ... EL layer forming Step, S16, S26, S33 ... anode layer forming step, S23, S34 ... periodic structure forming step, 3RH ... red base step, 3RS ... step surface, 4BH ... blue step, 4BS, 4GS, 4RS, 4WS ... cathode surface 4CB ... pitch for blue, 4CG ... pitch for green, 4CR ... pitch for red, 4GH ... step for green, 4RH ... step for red, 6BS, 6GS, 6RS ... anode surface, 6RH ... anode step, 10B, 10G, 10R , 10W ... pixel, 11 ... substrate, 12B, 12G, 12R, 12W ... pixel circuit, 13 ... insulating layer, 14, 14B, 14G, 14R ... shade Layers, 15B, 15G, 15R, 15W ... EL layers, 16, 16B, 16G, 16R ... anode layers, 17 ... insulating layers between anodes, 17S ... slopes between anodes, 20B, 20G, 20R ... pixel drive units, 25B, 25G , 25R ... color filter, 25W ... white transmission layer, 30B, 30G, 30R ... EL structure.

Claims (11)

A substrate,
A plurality of pixels provided on the substrate,
Each of the plurality of pixels is
A cathode layer, an anode layer, and an EL layer sandwiched between the cathode layer and the anode layer,
Having a fine relief structure at the interface between the cathode layer and the EL layer,
The plurality of pixels are:
Including at least two or more types of pixels having different emission colors,
Each of the two or more types of pixels is
An EL display device having the fine concavo-convex structure as a plasmonic structure in which a most frequent pitch is set so as to excite plasmon light included in a wavelength band corresponding to a half width of a peak in a light emission spectrum of the pixel. The EL layer included in the plurality of pixels emits white light,
Each of the two or more types of pixels has a color filter,
The EL display device according to claim 1, wherein the color filter emits a specific wavelength band from white light emitted from the EL layer. The two or more types of pixels are
The EL display device according to claim 1, wherein the EL display device includes a red light emitting pixel, a green light emitting pixel, and a blue light emitting pixel. The plurality of pixels include white light-emitting pixels,
4. The EL display device according to claim 3, wherein the fine uneven structure of the white light output pixel is a plasmonic structure in which the most frequent pitch is set so as to excite plasmon light over the entire wavelength band in which the white light output pixel emits light. . Either one of the cathode layer and the anode layer is a lower electrode layer,
Of the cathode layer and the anode layer, a layer different from the lower electrode layer is an upper electrode layer,
Each of the plurality of pixels is
The lower electrode layer, the EL layer, and the upper electrode layer are laminated in this order on the substrate,
Having a fine relief structure A at the interface between the lower electrode layer and the EL layer,
The interface between the EL layer and the upper electrode layer has a fine relief structure B having a shape following the shape of the fine relief structure A,
5. The EL according to claim 1, wherein a structure included in an interface between the cathode layer and the EL layer among the fine concavo-convex structure A and the fine concavo-convex structure B is the fine concavo-convex structure. Display device. The EL display device according to claim 5, wherein an average height of the concavo-convex structure in the fine concavo-convex structure A is equal to or higher than an average height of the concavo-convex structure in the fine concavo-convex structure B. Between the substrate and the lower electrode layer,
A pixel circuit connected to a part of the lower electrode layer and supplying a current to the EL layer;
An insulating layer that insulates the pixel circuits of the pixels adjacent to each other;
The interface between the insulating layer and the lower electrode layer has a fine relief structure C,
The EL display device according to claim 5, wherein the fine uneven structure A having a shape following the shape of the fine uneven structure C is provided at an interface between the lower electrode layer and the EL layer. The EL display device according to claim 7, wherein an average height of the concavo-convex structure in the fine concavo-convex structure C is equal to or greater than an average height of the concavo-convex structure in the fine concavo-convex structure A. A manufacturing method of an EL display device comprising a substrate and at least two or more kinds of pixels having different light emission colors provided on the substrate,
Forming a lower electrode layer on the substrate;
Forming an EL layer on the lower electrode layer;
Forming an upper electrode layer on the EL layer,
Forming a fine concavo-convex structure at the interface between the cathode layer, which is one of the lower electrode layer and the upper electrode layer, and the EL layer;
The most frequent pitch of the fine concavo-convex structure is set such that the fine concavo-convex structure excites plasmon light included in a wavelength band corresponding to a half width of a peak in the light emission spectrum of the pixel including the fine concavo-convex structure. A method for manufacturing an EL display device. Further comprising forming a fine relief structure D on the substrate;
The fine concavo-convex structure has a shape following the fine concavo-convex structure D, and an average height of the concavo-convex structure in the fine concavo-convex structure is equal to or less than an average height of the concavo-convex structure in the fine concavo-convex structure D. The manufacturing method of EL display apparatus as described in 1 .. The substrate has an insulating layer;
In the step of forming the lower electrode layer, the lower electrode layer is formed on the insulating layer,
The method for manufacturing an EL display device according to claim 10, wherein in the step of forming the fine uneven structure D, the fine uneven structure D is formed on the insulating layer.

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