JP2012248453A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL display device with an excellent viewing angle characteristic and high quality.SOLUTION: A display device includes at least a first light-emitting unit and a second light-emitting unit on a substrate. Each of the first light-emitting unit and the second light-emitting unit includes: a white-light-emitting element disposed on the substrate; a first protective film provided covering the white-light-emitting element; a color filter provided on the first protective film; and a second protective film provided on the color filter. The color filter of the first light-emitting unit is thinner than that of the second light-emitting unit. The second protective film has a lens member at a position corresponding to the position at which the white-light-emitting element is disposed. The first light-emitting unit has a film-thickness adjusting layer between the first protective film and the second protective film. The distance between the white-light-emitting element and the lens member of the first light-emitting unit is equal to that of the second light-emitting unit.

Description

  The present invention relates to a display device, and more particularly, to a display device including an organic EL (Electro Luminescence) element.

  An organic EL element is an electronic element having a pair of electrodes composed of an anode and a cathode, and an organic EL layer formed between the pair of electrodes and composed of one or more organic compound layers including a light emitting layer. Currently, organic EL elements have been actively researched and developed because of their characteristics (low driving voltage, various emission wavelengths, high-speed response, and light-emitting devices can be made thinner and lighter).

  In recent years, attention has been paid to a display device using these organic EL elements, that is, an organic EL display device as a thin display device replacing a liquid crystal display (LCD). Here, since the organic EL element is a self-luminous device, the organic EL display device has excellent performance with respect to viewing angle, contrast, and color reproducibility.

  As a method of displaying full color on an organic EL display device, there are a method of combining a plurality of organic EL elements capable of emitting different colors and a color filter method. Here, the color filter method is a method of obtaining full-color light emission by combining an organic EL element that emits white light and a colored layer that transmits one of the three primary colors of light, red, green, and blue.

  In the organic EL display device using this color filter method, light extraction efficiency is reduced due to increased light absorption by the color filter, compared to a method in which a plurality of organic EL elements emitting different colors are combined. Therefore, Patent Documents 1 and 2 disclose a configuration in which a microlens is combined with a color filter type organic EL display device to increase light extraction efficiency. Here, in the display device disclosed in Patent Document 1, a color filter and a microlens are formed in this order on a sheet including a sealing resin layer provided on an organic EL element. In the display device disclosed in Patent Document 2, a microlens and a color filter are formed in this order on an organic EL element. When the configurations of these display devices are compared, it is difficult to form a color filter along the surface of the microlens as in the display device of Patent Literature 1, and therefore the configuration of Patent Literature 2 is preferable in terms of manufacturing.

Japanese Patent Laid-Open No. 2004-127661 JP 2004-127661 A

By the way, in an organic EL display device having a white light emitting element and a color filter, the light transmittance decreases as the thickness of the color filter increases, but instead, the wavelength spectrum of the transmitted light becomes sharper, and color reproducibility. Becomes higher. Moreover, generally the tendency shown to the following (a) and (b) is seen in the color filter of each color (red, green, blue).
(A) The red color filter has higher white light transmittance than the green or blue color filter.
(B) The green color filter has higher brightness of transmitted light than the red or blue color filter.

  For this reason, the blue color filter, which has lower white light transmittance and lower transmitted light brightness than other color filters, as compared with the color filters of all colors, as in Patent Document 2, It is preferable to reduce the film thickness of the filter itself by giving priority to the transmittance over the reproducibility. As described above, it is desirable to change the film thickness of the color filter for each color according to the characteristics of transmitted light.

  However, if the film thickness of the color filter is made different for each color, it becomes difficult to keep the distance between the light emitting surface and the microlens the same regardless of the color, and the light collection rate varies for each color. Therefore, with this configuration, the light extraction efficiency varies for each color, and the viewing angle characteristics are degraded.

  As described above, in an organic EL display device that outputs a plurality of types of light, in the case of a configuration in which two or more color filters and a protective film having a microlens shape are stacked in this order on a white light emitting element, There was a problem that variation in light collection rate occurred every time.

  The present invention has been made to solve the above-described problems, and is to provide a display device having excellent viewing angle characteristics and high quality.

The display device of the present invention includes a white light emitting element disposed on a substrate,
A first protective film provided to cover the white light emitting element;
A color filter provided on the first protective film;
A second protective film provided on the color filter and including a lens member, and a display device in which a plurality of light emitting units are disposed,
The first protective film and the second protective film are layers common to the plurality of light emitting units,
The plurality of light emitting units includes a first light emitting unit having at least a first color filter, and a second light emitting unit having a second color filter having a thinner film thickness than the first color filter,
In the first light emitting unit and the second light emitting unit, the first protective film and the second protective film included in the second light emitting unit so that the distance between the white light emitting element and the lens member is equal to each other. A film thickness adjusting layer is provided between the two.

  According to the present invention, an organic EL display device having excellent viewing angle characteristics and high quality can be provided. That is, in the display device of the present invention, the film thickness adjusting layer is appropriately provided for the purpose of adjusting the distance from the light emitting surface to the lens member (microlens) in each light emitting unit. As a result, it is possible to eliminate the level difference caused by the difference in film thickness for each color of the color filter, and to suppress the variation in the light collection rate among the light emitting units.

It is a cross-sectional schematic diagram which shows 1st embodiment in the display apparatus of this invention. It is a cross-sectional schematic diagram which shows 2nd embodiment in the display apparatus of this invention.

  In the display device of the present invention, a plurality of light emitting units are arranged. Here, in each light emitting unit, a white light emitting element disposed on the substrate, a first protective film provided to cover the white light emitting element, a color filter provided on the first protective film, And a second protective film provided on the color filter and including a lens member. The light emitting unit constituting the display device of the present invention includes at least a first light emitting unit having a first color filter and a second light emitting unit having a second color filter. The features of the first light emitting unit and the second light emitting unit will be described later. Hereinafter, an organic EL display device which is one of display devices will be described as a specific example, but the present invention can also be applied to a display device using other light emitting elements such as inorganic EL elements and LEDs.

  Here, the white light emitting element is an organic EL element that is disposed on a substrate and emits white light.

  The first protective film is a protective film provided to cover the white light emitting element, and is formed as a layer common to the first light emitting unit and the second light emitting unit.

The color filter is a member provided on the first protective film. In the present invention, when the first color filter of the first light emitting unit and the second color filter of the second light emitting unit are compared, the film thickness of the second color filter is thinner than the first color filter. Yes. The color filters have different film thicknesses for each light emitting unit (thin film thickness of the second color filter provided in the second light emitting unit is reduced). This is because the properties of the filters are different. Specifically, the properties are different as shown in (i) and (ii) below.
(I) The color filter provided in the second light emitting unit has a lower transmittance of white light emitted from the white light emitting element than the color filter provided in the first light emitting unit. (Ii) Second light emission The brightness of the light that passes through the color filter provided in the unit is lower than the brightness of the light that passes through the color filter provided in the first light emitting unit. The second protective film is a protection provided on the color filter. The film is formed as a layer common to the first light emitting unit and the second light emitting unit, and has a lens member at a position corresponding to the arrangement position of the white light emitting element.

  The first light emitting unit has a film thickness adjusting layer between the first protective film and the second protective film. In addition, since the color filter is provided between the first protective film and the second protective film, the film thickness adjusting layer is provided between the first protective film and the color filter or between the color filter and the second protective film. Between.

  In the present invention, the distance between the white light emitting element and the lens member is the same in the first light emitting unit and the second light emitting unit. That is, the film thickness adjusting layer is a member provided to make the distance between the white light emitting element and the lens member uniform in each light emitting unit. In the present invention, the terms “same” and “uniform” do not mean completely identical or uniform, but also include those having errors within a range that does not affect display.

  The above description relates to an organic EL display device in which two types of light emitting units having different emission colors are provided in the device, but the present invention is not limited to this. As a specific example, a display device in which three types of light emitting units (first light emitting unit, second light emitting unit, and third light emitting unit) having different emission colors are provided in the device will be described. In this display device, the film thickness of three types of color filters (first color filter, second color filter, and third color filter) provided for each light emitting unit is adjusted as appropriate according to the properties. For this reason, in this invention, the film thickness of the color filter which at least 1st light emission unit, 2nd light emission unit, or 3rd light emission unit has differs from the film thickness of the color filter which other light emission units have. For example, a display device in which the film thickness of the first color filter included in the first light emitting unit is made thinner than the film thickness of the color filter included in other light emitting units (second light emitting unit, third light emitting unit) will be described. . In such a display device, the first light emitting unit is provided between the first protective film and the second protective film so that the distance between the white light emitting element and the lens member is equal (uniform) in each light emitting unit. A film thickness adjusting layer is provided. Similarly, when there are four or more types of light emitting units, a film thickness adjusting layer may be appropriately provided so that the distance between the white light emitting element and the lens member is equal (uniform) in each light emitting unit. Specifically, a film thickness adjusting layer is provided between the first protective film and the second protective film for the other light emitting units in accordance with the light emitting unit having the thickest color filter.

  Hereinafter, embodiments of an organic EL display device according to the present invention will be described with reference to the drawings. In the present invention, well-known or publicly-known techniques in the technical field can be applied to portions that are not particularly illustrated or described. Further, the embodiment described below is only one embodiment of the present invention, and the present invention is not limited to these embodiments.

  FIG. 1 is a schematic cross-sectional view showing a first embodiment of the display device of the present invention. The organic EL display device 1 of FIG. 1 is provided on a substrate 10 with three types of light emitting units that output different colors, that is, a red light emitting unit 2R, a green light emitting unit 2G, and a blue light emitting unit 2B. In the organic EL display device 1 of FIG. 1, the three types of light emitting units (2R, 2G, 2B) are gathered one by one to form one pixel, and a plurality of pixels are arranged on the substrate 10 in a matrix. Has been. The organic EL display device 1 of FIG. 1 is a top emission type display device that emits light in the opposite direction of the substrate 10 from the upper surface of an organic EL element (a white light emitting element 20 described later) formed on the substrate 10. is there.

  Each light emitting unit (2R, 2G, 2B) has a white light emitting element 20, a protective film 30 (first protective film), a color filter 40 (40R, 40G, 40B), and a second protection on the substrate 10, respectively. The film 50 is provided in this order.

  Hereinafter, components of the organic EL display device 1 of FIG. 1 will be described.

  As the substrate 10 constituting the organic EL display device 1 of FIG. 1, a substrate in which a pixel circuit (not shown) is formed on a base material (not shown) is used. That is, the organic EL display device 1 in FIG. 1 is an active matrix drive type display device. The pixel circuit formed on the substrate can be manufactured by a known transistor manufacturing technique. The pixel circuit is composed of a plurality of transistors. An interlayer insulating film (not shown) and a planarizing film (not shown) are provided on the pixel circuit for the purpose of protecting the plurality of transistors and planarizing the substrate 10. Further, contact holes (not shown) are formed at predetermined positions in the interlayer insulating film and the planarizing film. This contact hole is provided to electrically connect the pixel circuit and the lower electrode 21 (anode) constituting the white light emitting element 20. With this contact hole, the organic EL display device 1 of FIG. 1 can be independently driven on a pixel-by-pixel basis.

  The white light emitting element 20 provided on the substrate 10 includes a lower electrode 21 (anode) provided on the substrate 10, a white organic EL layer 22 provided on the lower electrode 21, and an upper portion provided on the white organic EL layer 22. This is a member composed of an electrode 23 (cathode).

  The lower electrode 21 is formed in a desired pattern at a position corresponding to the position where the light emitting units (2R, 2G, 2B) are provided. In the case of a top emission type organic EL display device, the lower electrode 21 (anode) is an electrode layer made of a conductive material having a high reflectance. Examples of the conductive material having high reflectivity include metal materials having high reflectivity such as Cr, Al, Ag, Au, and Pt.

  The lower electrode 21 may be a single-layer electrode having only a layer made of a conductive material having a high reflectance described above, or a layer made of a conductive material having a high reflectance and a layer made of a transparent conductive material are laminated. It may be a laminated electrode. When the lower electrode 21 is a laminated electrode, the transparent conductive material that is a constituent material of the layer made of the transparent conductive material constituting the laminated electrode is not particularly limited as long as it has excellent hole injection properties. . For example, ITO, IZO, ZnO, etc. are mentioned.

  The electrode thin film constituting the lower electrode 21 can be formed using a known method such as a sputtering method. In this embodiment, Ag is deposited to a thickness of 100 nm, and ITO is deposited to a thickness of 20 nm. The electrode thin film thus formed is patterned to correspond to each light emitting unit by a known method such as photolithography patterning.

  In the organic EL display device 1 of FIG. 1, the lower electrode 21 is partitioned for each light emitting unit by a partition wall 11 provided on the substrate 10. The bank 11 that partitions the lower electrode 21 for each light emitting unit (subpixel unit) is preferably made of an insulating material having excellent flatness. Among these, a material that can easily form a film by a wet method such as a coating method and can be applied with photolithography patterning is more preferable. For example, a resin material such as a photosensitive acrylic resin or a polyimide resin is preferably used. In addition, what is necessary is just to provide the partition 11 as needed and may omit it.

  The white organic EL layer 22 provided on the lower electrode 21 and the bank 11 is a laminated body composed of a single layer or a plurality of layers having at least a light emitting layer (not shown). It is a layer made of an organic compound. In the organic EL display device 1 of FIG. 1, the white organic EL layer 22 is formed as a layer common to all the light emitting units.

  Examples of the layer constituting the white organic EL layer 22 include a hole injection / transport layer, an electron block layer, a hole block layer, and an electron injection / transport layer in addition to the light emitting layer (white light emitting layer). However, the present invention is not limited to these. Hereinafter, the case where the white organic EL layer 22 is a laminate including a hole injection / transport layer, a white light emitting layer, and an electron injection / transport layer in order from the anode (lower electrode 21) side will be described.

  The hole injection / transport layer is a layer composed of a single layer or a plurality of layers made of an organic compound having a function of hole injection or hole transport or both. That is, the hole injection / transport layer includes not only a hole injection layer and a hole transport layer but also a laminate composed of a hole injection layer and a hole transport layer. Moreover, a well-known material can be used as a constituent material of a positive hole injection / transport layer.

  The hole injection / transport layer can be formed and formed by a known method such as vacuum deposition. The film thickness of the hole injection / transport layer is appropriately set in consideration of the hole injection / transport ability of the material constituting the layer. In this embodiment, the hole injection / transport layer is formed to a thickness of 150 nm.

  The white light emitting layer is an organic compound layer that emits white light, and a red light emitting material, a green light emitting material, and a blue light emitting material are included in the layer. Further, the white light emitting layer may be a single layer or a laminate in which a plurality of layers are combined.

  When the white light emitting layer is a laminated body in which a plurality of layers are combined, the combination of layers is, for example, a combination of a layer containing a yellow light emitting material and a layer containing a cyan light emitting material, a layer containing an orange light emitting material and a cyan light emitting material And a combination of a layer containing a yellow light emitting material and a layer containing a blue light emitting material. In this embodiment, a stacked body of a layer containing a yellow light emitting material and a layer containing a cyan light emitting material is formed. Specifically, first, a layer containing a cyan light emitting material is formed to a thickness of 10 nm by a vacuum evaporation method, and a layer containing a yellow light emitting material is formed thereon to a thickness of 10 nm.

  The electron injection / transport layer is a layer composed of a single layer or a plurality of layers made of an organic compound having the functions of electron injection and / or electron transport. That is, the electron injection / transport layer includes not only the electron injection layer and the electron transport layer, but also a laminate composed of the electron injection layer and the electron transport layer. Moreover, a well-known material can be used as a constituent material of an electron injection / transport layer.

  In this embodiment, an electron transport layer and an electron injection layer are laminated in this order on the white light emitting layer. Specifically, on the white light emitting layer, the electron transport layer is formed with a thickness of 10 nm, and then the electron injection layer is formed with a thickness of 80 nm by vacuum deposition.

  Similar to the white organic EL layer 22, the upper electrode 23 formed on the white organic EL layer 22 is formed as a layer common to all the light emitting units. In the top emission type organic EL display device, the upper electrode 23 (cathode) formed on the white organic EL layer 22 has a transmittance so that light extracted from the white light emitting layer can be extracted outside the device. It is made of a highly conductive material. That is, the upper electrode 23 is a light extraction electrode. As the upper electrode 23, for example, a transparent conductive film formed of a transparent conductive material such as ITO, IZO, ZnO or the like with a film thickness of about 10 nm to 1000 nm is preferably used. Further, a semi-transmissive film in which a metal material such as Ag, Au, or Al is formed with a thickness of about 10 nm to 30 nm is also preferably used. In this embodiment, ITO is formed to 1000 nm by a sputtering method.

  The protective film 30 (first protective film) provided on the white light emitting element 20 is formed to protect the white light emitting element 20 from the photolithographic process performed when forming the oxygen and moisture in the air and the color filter 40. The The constituent material of the protective film 30 is an insulating material having optical transparency. Specifically, an insulating film such as SiN, SiON, or SiO can be used. The protective film 30 is formed by a known method such as a CVD method. The protective film 30 is desirably formed with a uniform thickness at least in the light emitting region of each light emitting unit. In this embodiment, SiN is formed with a film thickness of 1 μm by CVD.

  In the organic EL display device 1 of FIG. 1, a black matrix 31 is provided in a non-light emitting region (a region where the lower electrode 21 is not provided) on the protective film 30. The black matrix 31 is patterned in a region corresponding to a non-light emitting region on the protective film 30 for the purpose of preventing color mixture that may occur when adjacent white light emitting elements emit light or preventing diplomatic reflection. Yes. However, in the present invention, this black matrix 31 may be omitted. The black matrix 31 can be manufactured using a known technique using a known material.

  In the organic EL display device 1 of FIG. 1, a film thickness adjusting layer 41 is provided between the protective film 30 and a blue color filter 40B described later. In this embodiment, as shown in FIG. 1, the film thickness adjusting layer 41 is provided only in the blue light emitting unit 2B, but the present invention is not limited to this. That is, when the film thickness of the red or green color filter is smaller than that of the blue color filter, the film thickness adjusting layer 41 is replaced with the red light emitting unit 2R or green instead of the blue light emitting unit 2B according to the film thickness difference. It may be provided in the light emitting unit 2G, or may be formed in each of a plurality of types of light emitting units.

  In the present embodiment, the blue color filter 40B is thinner than the other color filters (40R, 40G) in consideration of the light transmittance of the color filter and the luminance of the light transmitted through the color filter. Is set. Therefore, the film thickness adjusting layer 41 is selectively provided in the blue light emitting unit 2B in order to make the distance between the white light emitting element 20 and a lens member 52 described later equal (same) in each light emitting unit.

  The film thickness adjusting layer 41 can be produced, for example, by patterning a film formed by coating (coating) a light transmissive resin material such as acrylic resin or polyimide resin into a desired shape. It can also be produced by patterning a film formed of a light transmissive insulating material such as SiN, SiON, or SiO by a CVD method into a desired shape. In the present embodiment, a thin film made of acrylic resin is formed (coated) with a film thickness of 1 μm, and the film thickness is selectively formed on the protective film 30 formed in the region of the blue light emitting unit 2B by a known patterning technique. The adjustment layer 41 is formed.

  On the protective film 30 (first protective film) or the film thickness adjusting layer 11, a color filter 40 made of a color resist is formed. In the organic EL display device 1 of FIG. 1, color filters corresponding to the colors of light respectively output from three types of light emitting units (red light emitting unit 2R, green light emitting unit 2G, and blue light emitting unit 2B) are provided. Specifically, a red color filter 40R, a green color filter 40G, and a blue color filter 40B are provided. The color filter of each color can be produced at a position corresponding to the light emitting unit of each color by repeating film formation (coating) and processing (patterning).

  In this embodiment, the film thickness of the blue color filter 40B is set thinner than the other color filters (40R, 40G). As the thickness of the color filter 40 made of a color resist increases, light output from the white light emitting element can be transmitted with high color purity, but at the same time, the transmittance of the filter itself decreases. For this reason, it is necessary to appropriately adjust the film thickness of the color filter 40 in accordance with the wavelength of light to be extracted in consideration of the light transmittance of each color filter. Therefore, in this embodiment, since the luminance of the light transmitted through the blue color filter is lower than that of the other color filters (red color filter, green color filter), the film thickness of the blue color filter 40B is set to maintain the luminance balance. Thinly set. Specifically, the film thicknesses of the blue color filter 40B, the red color filter 40R, and the green color filter 40G are set to 1 μm, 2 μm, and 2 μm, respectively.

  Thus, since the film thickness of the blue color filter 40B is 1 μm thinner than the other color filters (40R, 40G), the film thickness adjustment layer 41 is formed between the blue color filter 40B and the protective film 30. Provided at 1 μm.

As described above, in the blue light emitting unit 2B, the film thickness adjusting layer 41 is provided between the protective film 30 (first protective film) and the color filter 40 (40B), so that the blue color filter 40B and other color filters ( 40G, 40R) to fill the difference in surface height. Specifically, the thicknesses of the color filters 40B, 40G, and 40R for the respective colors are d ₁ (= 1 μm), d _G (= 2 μm), and d _R (= 2 μm), respectively, and the thickness of the film thickness protective film 41 is set. Is the difference d ₂ (= 1 μm) between d ₁ and d _G (or d _R ). Thereby, there exist the following effects. That is, the distance from the upper surface of the white light emitting element 20 to the lower surface of the overcoat layer 51 constituting the second protective film 50 is the same in each pixel. Further, when the overcoat layer 51 is formed in each light emitting unit with a uniform film thickness (at least in the light emitting region), from the upper surface of the white light emitting element 20 to the lower surface of the lens member 52 constituting the second protective film 50. The distances D _B , D _G and D _R are all the same. Thereby, the dispersion | variation in the condensing rate between each light emission unit in an organic electroluminescence display can be suppressed. Furthermore, the lens member 52 can be formed on the color filter 40 without deteriorating the appearance.

In this embodiment, the film thicknesses of the blue color filter 40B and the film thickness adjusting layer 41 are adjusted according to the characteristics of the light generated from the white light emitting element and transmitted through the color filter (the brightness of the transmitted light). It is not limited to this form. That is, the difference in film thickness of each color filter 40 (40R, 40G, 40B) set in accordance with an element (light transmittance of each color filter, etc.) other than the above-described light characteristics (luminance of transmitted light) is a film. It is filled (dissolved) by the thickness adjusting layer 41. That is, when D _B , D _G , and D _{R in} FIG. 1 are different due to the different film thicknesses of the color filters, the film thickness adjusting layer 41 is provided as appropriate, so that D _B , D _G , Adjust so that D _R are all equal.

  The film thickness adjusting layer 41 may be provided in all the light emitting units. In such a case, from the viewpoint of light collection efficiency, in the light emitting unit having the largest film thickness of the color filter, it is desirable to make the film thickness adjusting layer 41 as thin as possible.

  On the other hand, in order to make it easier to form a lens member 52 to be described later, the cross-sectional shape of the color filter 40 is preferably a so-called mortar shape having a peripheral portion higher than a central portion as shown in FIG. .

  After the color filter 40 is formed, a second protective film 50 having a lens member 52 (microlens) is formed on the color filter 40. In the present embodiment, the second protective film 50 is a member in which an overcoat layer 51 and a lens member 52 are laminated in this order.

  The overcoat layer 51 is a member provided to cover and protect the color filter 40 and to smooth the surface by filling the steps and gaps between the color filters (40R, 40G, 40B). The overcoat layer 51 is formed of, for example, a transparent resin such as an acrylic resin. In consideration of the light collection rate of each light emitting unit, it is preferable to form the overcoat layer 51 as thin as possible. In this embodiment, an acrylic resin is formed (coated) with a film thickness of 200 nm.

The lens member 52 (microlens) formed on the overcoat layer 51 is a member formed in an array and a hemisphere. The constituent material of the microlens is not particularly limited as long as it is a transparent material. For example, an inorganic transparent film such as SiN, SiON, or SiO, or a resin film such as acrylic or epoxy is used. Here, the microlens can be manufactured by any one of the manufacturing methods shown in the following (1) to (6).
(1) A method in which a resin layer patterned by a photolithography process or the like is heat-treated, and the resin layer is deformed into a microlens shape by reflow.
(2) A method of forming a microlens by forming a photocurable resin layer with a uniform film thickness, then exposing it to light having a distribution in the in-plane direction, and developing the exposed resin layer.
(3) A method of forming a transparent thin film made of an inorganic material with a uniform film thickness and then processing the transparent thin film into a microlens shape by a photolithography process.
(4) A method of processing the surface of a transparent thin film or a resin layer made of an inorganic material formed with a uniform film thickness by irradiation with an ion beam, an electron beam, a laser, or the like into a microlens shape.
(5) A method of forming a microlens in a self-aligning manner by dropping an appropriate amount of resin on each pixel.
(6) A method of forming a microlens by preparing a resin sheet on which a microlens is formed in advance separately from the substrate on which the organic light emitting element is formed, aligning the two, and then bonding them together.

  In the present embodiment, the arrayed and hemispherical lens member 52 is formed using (3) and (1) in this order. Specifically, first, SiN is uniformly formed with a thickness of 30 μm by a CVD method, and then uniformly coated with a resist with a thickness of 20 μm. After patterning the resist in an array, a microlens shape is formed by reflow. Thereafter, SiN is receded and etched using the resist having a microlens shape as a shadow mask to form the microlens 10. Finally, a thermoplastic epoxy resin film is applied for surface protection and completed.

  The microlens constituting the display device of the present invention may be a hemispherical shape or a bowl-shaped semicylindrical shape. In the case of a bowl-shaped semi-cylindrical shape, it is advantageous in that it has a light collecting function in either the vertical or horizontal directions. The semicylindrical end in the length direction may be hemispherical, or the end face may be formed perpendicular to the substrate.

As described above, in the organic EL display device described in this embodiment, the distances D _B , D _G , and D _R from the light emitting surface (white light emitting element 22) to the micro lens (lens member 52) are independent of the color of the color filter 40. Since it can be made the same, the dispersion | variation in condensing rate can be suppressed. In addition, the lens member 52 can be formed on the color filter 40 without deteriorating the appearance. Therefore, a high-quality organic EL display device excellent in viewing angle characteristics can be provided.

  The display device of the present invention can be used for mobile applications in which it is important to improve visibility by high luminance, for example, a rear display of a digital camera, a display for a mobile phone, or the like. In addition, since low power consumption is expected even at the same luminance, it can also be used for lighting or the like used indoors.

  Further, the present invention is not limited to the above-described embodiment without departing from the above-described purpose, and various applications and modifications are possible.

  FIG. 2 is a schematic cross-sectional view showing a second embodiment of the display device of the present invention. The organic EL display device 3 in FIG. 2 has the same configuration as the organic EL display device 1 in FIG. 1 except for the arrangement position of the film thickness adjusting layer 41 as compared with the organic EL display device 1 in FIG. Hereinafter, the organic EL display device 3 of FIG. 2 will be described focusing on differences from the organic EL display device 1 of FIG.

  The organic EL display device 3 in FIG. 2 is common to the organic EL display device 1 in FIG. 1 with respect to the substrate 10, the bank 11, the white light emitting element 20, the protective film 30 (first protective film), and the black matrix 31. For this reason, when forming the white light emitting element 20, the protective film 30 (first protective film), and the black matrix 31 on the substrate 10 in this order, the same method as in the first embodiment can be used.

In this embodiment, after the black matrix 31 is formed, the color filters (40R, 40G, 40B) are formed at positions corresponding to the respective light emitting units (2R, 2G, 2B). Here, the film thicknesses d _R , d _G , and d ₁ of the color filters (40R, 40G, and 40B) are set to 2 μm (40R), 2 μm (40G), and 1 μm (40B), respectively. With this setting, the film thickness of the blue color filter 40B is 1 μm thinner than the other color filters 40R and 40G.

After forming the color filters (40R, 40G, 40B), the film thickness adjusting layer 41 is formed with a film thickness of 1 μm on the blue color filter 40B. As a result, the sum of the film thickness d ₁ of the blue color filter 40B and the film thickness d ₂ of the film thickness adjusting layer 41 becomes equal to the film thicknesses d _R and d _{G of the} other color filters (40R, 40G). That is, the distance from the upper surface of the white light emitting element 20 to the lower surface of the overcoat layer 51 corresponding to the lower surface of the second protective film 50 having the lens member 52 (microlens) is the same. Thus, an overcoat layer 51 by forming a uniform (at least a light-emitting region) thickness in each light-emitting unit, a distance D _R, D _G to the microlens from the light emitting surface in each light emitting unit, the color of D _B The filter 40 can be the same regardless of the color. For this reason, the dispersion | variation in the condensing rate between each light emission unit can be suppressed. Furthermore, the lens member 52 can be formed on the color filter 40 without deteriorating the appearance.

In this example, the film thicknesses of the blue color filter 40B and the film thickness adjusting layer 41 are adjusted according to the light emission from the white light emitting element, but the present invention is not limited to this embodiment. In the present invention, the film thickness adjustment layer 41 eliminates the difference in film thickness for each color of the color filter 40 that occurs according to the material of the white organic EL layer 22 to be used and the light emission luminance. That is, when D _B , D _G , and D _{R in} FIG. 2 are different due to the different film thicknesses of the color filters, the film thickness adjusting layer 41 is provided as appropriate so that D _B , D _G , Adjust so that D _R are all equal.

  The film thickness adjusting layer 41 may be provided in all the light emitting units. In such a case, from the viewpoint of light collection efficiency, in the light emitting unit having the largest film thickness of the color filter, it is desirable to make the film thickness adjusting layer 41 as thin as possible.

As described above, in the organic EL display device described in the present embodiment, the distances D _B , D _G , D _R from the white light emitting element to the lens member 52 can be made the same regardless of the color of the color filter 40, Variation in light collection rate can be suppressed. In addition, a microlens can be formed on the color filter 40 without deteriorating the appearance. Therefore, a high-quality organic EL display device excellent in viewing angle characteristics can be provided.

  1 (2): organic EL display device, 10: substrate, 11: bank, 21: lower electrode, 22: white organic EL layer, 23: upper electrode, 30: protective film (first protective film), 31: black matrix 40 (40R, 40G, 40B): color filter, 41: film thickness adjusting layer, 50: second protective film, 51: overcoat layer, 52: lens member (microlens)

Claims (2)

A white light emitting element disposed on a substrate;
A first protective film provided to cover the white light emitting element;
A color filter provided on the first protective film;
A second protective film provided on the color filter and including a lens member, and a display device in which a plurality of light emitting units are disposed,
The first protective film and the second protective film are layers common to the plurality of light emitting units,
The plurality of light emitting units includes a first light emitting unit having at least a first color filter, and a second light emitting unit having a second color filter having a thinner film thickness than the first color filter,
In the first light emitting unit and the second light emitting unit, the first protective film and the second protective film included in the second light emitting unit so that the distance between the white light emitting element and the lens member is equal to each other. A display device, wherein a film thickness adjusting layer is provided between the display device and the display device. A white light emitting element disposed on a substrate;
A first protective film provided to cover the white light emitting element;
A color filter provided on the first protective film;
A second protective film provided on the color filter and including a lens member, and a display device in which a plurality of light emitting units are disposed,
The first protective film and the second protective film are layers common to the plurality of light emitting units,
The plurality of light emitting units includes at least a first light emitting unit having a first color filter, a second light emitting unit having a second color filter, and a third light emitting unit having a third color filter,
The film thickness of the color filter that at least the first light emitting unit, the second light emitting unit, or the third light emitting unit has is different from the film thickness of the color filter that the other light emitting units have,
In the first light-emitting unit, the second light-emitting unit, and the third light-emitting unit, the first light-emitting unit, the second light-emitting unit, and the second light-emitting unit are arranged such that the distance between the white light-emitting element and the lens member is equal to each other. A display device, wherein a film thickness adjusting layer is provided between the first protective film and the second protective film included in the light emitting unit or the third light emitting unit.

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