JP2014013703A - Display element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display element which is obtained by forming functional film on a substrate through a wet process and improved so that the difference in film thickness of the functional film between a center portion and a peripheral portion of a display area caused by the difference in dry speed therebetween is suppressed.SOLUTION: A display element 100 has a display area in which plural pixels are arranged in a matrix form, and has a substrate 101 on which a base layer 111 containing a first electrode 102 is laminated, a partition wall 105 which is located above the base layer 111 and defines an opening portion, a function layer 106 located above the base layer 111 and within the opening portion, and a second electrode 108 confronting the first electrode 102 through the function layer 106. The end portion of the upper surface of the function layer 106 of a pixel existing at the center portion of the display area is located to be higher than the end portion of the upper surface of the function layer 106 of a pixel existing at the peripheral edge portion of the display area.

Description

  The present invention relates to a display element and a manufacturing method thereof, and more particularly to a display element in which a functional film is formed on a substrate by a wet process using a discharge device that discharges liquid such as ink and functional liquid, and a manufacturing method thereof. .

In display elements and devices such as organic EL display panels and TFT substrates, functional films for exhibiting specific functions are used. Examples of the functional film include an organic light emitting layer in an organic EL display panel and an organic semiconductor layer in a TFT substrate.
Currently, devices have been increased in size, and a wet process for applying an ink containing a functional material based on an inkjet method or the like has been proposed as an efficient method for forming a functional film. The wet process has a merit that the positional accuracy when the functional film is separately applied does not depend on the substrate size, and the technical barrier to device enlargement is relatively low.

In a typical ink-jet wet process, a substrate to be coated is placed on a work table of a coating apparatus. The ink head is scanned in one direction with respect to the substrate surface, and ink is dropped from a plurality of nozzles of the inkjet head onto a predetermined region of the substrate surface. Thereafter, the ink solvent is evaporated and dried to form a functional film.
By the way, in the wet process in which the functional layer is formed by the method of filling the ink on the substrate and drying, in the process of evaporating and drying the solvent of the ink, the peripheral part is the peripheral part in the film forming area. Since the solvent vapor pressure is lower in the part than in the central part, the solvent drying rate is higher. As a result, the functional layer of the pixel formed at the central portion of the substrate and the functional layer of the pixel formed at the edge of the substrate tend to have different shapes. As described above, when the shape of the functional layer is different between the pixel at the central portion of the substrate and the pixel at the peripheral portion of the substrate, the characteristics of the functional layers are also different from each other.

In order to solve such a problem, a technique has been provided in which a peripheral portion is filled with a larger amount of a solution containing a functional layer material than a central portion to suppress a drying speed difference and improve a film shape difference.
FIG. 13A is a plan view showing the configuration of the organic EL device described in Patent Document 1, and FIG. 13B is a cross-sectional view taken along line AA in FIG. The diameter of the top surface of the bank B12 of the light emitting elements in the regions R1, R2, and R3 from the center to the end in the ink application region R is set to a constant value J regardless of the region, and the diameter of the bottom is set to the end from the center. By setting T1 <T2 <T3, the ink E12 is applied in a larger amount in the vicinity of R1 <R2 <R3. Thus, the thickness of the coating layer is made uniform over the entire area of the coating region R by making the drying rate uniform over the entire region of the coating region R.

 14A is a plan view showing the configuration of the organic EL device described in Patent Document 2, and FIG. 14B is a side sectional view of FIG. 14A. Of the ink application area SA corresponding to the light emitting area EA provided on the substrate 1, the height h2 of the partition wall 35 in the peripheral area SA2 is higher than the height h1 of the partition wall 34 in the central area SA1. The film formation region A is filled with a large amount of liquid. Thereby, the difference in the drying rate between the central region and the peripheral region in the drying process can be suppressed, and a functional film having a stable film shape can be manufactured for each region in the coating region.

JP 2008-16205 A JP 2011-146184 A

However, the configurations described in Patent Document 1 and Patent Document 2 have a problem that the manufacturing method is complicated because the amount of ink filled in each pixel is changed according to the application region.
The present invention has been made in view of the above-described conventional problems. In a display element in which a functional film is formed on a substrate by a wet process using a discharge device that discharges liquid such as ink and functional liquid, the manufacture is simple. A display element that has improved the difference in film thickness of the functional film between the central portion and the peripheral portion of the display region caused by the difference in drying speed between the central portion of the display region of the substrate and the peripheral portion of the display region by the method, And it aims at providing the manufacturing method.

  A display element according to one embodiment of the present invention is a display element having a display region in which a plurality of pixels are arranged in a matrix, and includes a substrate over which a base layer including a first electrode is stacked, and the base layer A partition wall that defines an opening, a functional layer that is located above the base layer and is located in the opening, and a second electrode that faces the first electrode through the functional layer, And the end of the upper surface of the functional layer in the pixel existing in the central portion of the display region is positioned higher than the end of the upper surface of the functional layer in the pixel existing in the peripheral portion of the display region.

  According to the present invention, in a display element in which a functional film is formed on a substrate by a wet process using a discharge device that discharges liquid such as ink or functional liquid, the central portion and the periphery of the display region that cause uneven brightness A display element in which the difference in film thickness of the functional film from the portion is improved and a manufacturing method thereof can be provided by a simple manufacturing process.

Explanatory drawing which shows the difference in the film-forming shape between the center part of the display area which concerns on the conventional structure, and the peripheral part of a display area Cross-sectional profile of functional film according to conventional configuration Explanatory drawing which shows the change of the shape of a functional film at the time of raising the ink pinning position of the functional layer which exists in the center part of a display area Explanatory drawing which shows the difference in the shape of the functional film of the center part of a display area, and the peripheral part of a display area when the ink pinning position of the functional layer which exists in the center part of a display area is raised Sectional drawing which shows the partial cross section of the organic EL element which concerns on 1 aspect of Embodiment 1 typically 1 is a configuration diagram of a substrate in which a partition wall used in an organic EL element according to one embodiment of the first embodiment is provided. Typical sectional drawing which shows the manufacture process of the manufacturing method of the organic EL element which concerns on 1 aspect of Embodiment 1. FIG. Typical sectional drawing which shows the manufacture process of the manufacturing method of the organic EL element which concerns on 1 aspect of Embodiment 1. FIG. Sectional drawing which shows the relationship between the partition height of the Example of the organic EL element which concerns on 1 aspect of Embodiment 1, and an ink pinning position Sectional drawing which shows the change of the cross-sectional profile of a functional film at the time of changing the height of the partition in the center part of the display area of the Example of the organic EL element which concerns on 1 aspect of Embodiment 1 Sectional drawing which shows the change of the cross-sectional profile of a functional film in the peripheral part of the display area of the Example of the organic EL element which concerns on 1 aspect of Embodiment 1 Sectional drawing which shows the partial cross section of the organic EL element which concerns on 1 aspect of Embodiment 2 typically A plan view and a sectional view showing the configuration of a conventional organic EL device A plan view and a sectional view showing the configuration of a conventional organic EL device

≪Background to the form for carrying out the present invention≫
In the wet process in which the functional layer is formed by filling the substrate with ink and drying, the inventor forms a film formation shape due to a difference in drying speed between the central portion of the display region on the substrate and the peripheral portion of the display region. We conducted an extensive study on variations. FIG. 1 is an explanatory diagram showing the difference in film formation shape between the central portion of the display region and the peripheral portion of the display region according to the conventional configuration tested by the inventors, and FIG. 2 shows the configuration of the conventional display device. FIG. 2A is an overall view of the cross-sectional profile of the functional layer, and FIG. 2B is an enlarged view showing the cross-sectional profile of the bottom of the functional layer. Here, in FIGS. 2A and 2B, the solid line in the figure indicates the experimental result of measuring the cross-sectional profile of the functional layer in the central portion of the display region, and the broken line indicates the functional layer in the peripheral portion of the display region. The experimental result which measured the cross-sectional profile is shown. In FIG. 1, reference numeral 101 denotes a substrate, and reference numeral 105 denotes a first partition disposed on the substrate 101. The first opening 220 is defined between the first partition and the first partition. Reference numeral 106 denotes a functional layer formed in the first opening 220 of the first partition wall 105, and 106 ′ denotes ink filled in the first opening 220 to form the functional layer. As shown in FIG. 1 and FIG. 2, when the device is manufactured with the first partition 105 having a uniform height in the plane, the central portion A (hereinafter referred to as the central portion A) of the display region having a high vapor concentration and slow drying. In the pixel of (omitted), the functional layer 106 is thinned in the vicinity of the side wall as compared with the pixel of the peripheral portion B or C (hereinafter abbreviated as the peripheral portion B or C) of the display region having a relatively low vapor concentration and quick drying. The center is thickened. In the central portion A, which is slow to dry, it is considered that the solid component constituting the functional layer ink 106 ′ settles and moves to the bottom of the first opening 220 in the process of evaporation of the solvent, and increases the thickness of the bottom. It is done.

The inventor can make the film thickness of the bottom part of the central part A uniform with the film thickness of the bottom part of the peripheral part B or C if it can be dried in a state in which the amount of ink adhering to the wall surface is secured even in the slow-drying central part A We focused on the points that can be made. And the earnest examination was done about the realization means. The examination results will be described with reference to the drawings. FIG. 3 is an explanatory diagram showing a change in the shape of the functional layer 106 when the ink pinning position of the functional layer 106 in the central portion A is increased. Here, the ink pinning position of the functional layer is the position of the end of the upper surface of the functional layer on the side surface of the partition wall. FIG. 4 is an explanatory diagram showing the difference in the shape of the functional layer 106 between the central portion A and the peripheral portion B or C when the ink pinning position of the functional layer 106 existing in the central portion A is increased. As shown in FIGS. 3 and 4, by increasing the position (ink pinning position) of the upper surface of the functional layer in the central portion A from P1 to P2, even in the slow drying central portion A, It has been found that the amount of ink attached can be increased and a film shape similar to the peripheral portion B or C can be formed in the central portion A. And it came to the one aspect | mode of embodiment of this invention which improves the difference in the film thickness which originates in the drying speed difference of the center part A and the peripheral part B, and causes a brightness nonuniformity.
<< Outline of Embodiment for Implementing the Present Invention >>
A display element according to one embodiment of a mode for carrying out the present invention is a display element having a display region in which a plurality of pixels are arranged in a matrix, and a substrate on which a base layer including a first electrode is stacked A partition wall that is located on the foundation layer and defines an opening; a functional layer that is above the foundation layer and is located in the opening; and a first layer that faces the first electrode through the functional layer. The edge of the upper surface of the functional layer in the pixel existing in the central portion of the display region is positioned higher than the edge of the upper surface of the functional layer in the pixel existing in the peripheral portion of the display region. It is characterized by that.

Here, “high” means that the distance from the main surface in a direction perpendicular to the main surface of the substrate is large. The “main surface of the substrate” refers to the surface of the substrate surface on which the functional layer is disposed.
Moreover, in another aspect, the said partition existing in the said center part may be a structure higher than the said partition existing in the said peripheral part.
In another aspect, the partition in the pixel located in the central portion of the display area may be higher than the partition in the pixel located in the peripheral part of the display area.

In another aspect, the side surface of the partition wall of the pixel existing in the peripheral portion of the display area and the portion above the portion where the end of the upper surface of the functional layer formed in the opening defined by the partition wall is in contact is repelled. The liquid property may be higher than the liquid repellency of the partition portion corresponding to the portion and existing in the central portion of the display area.
In another aspect, the partition walls in the pixels existing in the peripheral portion of the display region are 0.5 μm or more and 1.0 μm or less in height higher than the partition walls in the pixel existing in the central portion of the display region. It may be a configuration.

In another aspect, the display area has a square shape, and a peripheral portion of the display area is on the center side of 5% of the length of one side of the square and the other side adjacent to the one side from the one side. The structure which exists in the range between the parallel lines with the said one side located may be sufficient.
In another aspect, the liquid repellency of the top of the partition in the pixel located in the peripheral portion of the display area is equal to the side surface of the partition in the pixel located in the center of the display area having the same height as the top. The structure may be higher than the liquid repellency possessed by.

 A display element manufacturing method according to an aspect of an embodiment for carrying out the present invention is a method for manufacturing a display element having a display region in which a plurality of pixels are arranged in a matrix, and includes a first electrode on a substrate. A base layer forming step for disposing a base layer including a barrier layer forming step for forming a partition wall defining an opening on the base layer, and a functional layer material for filling the opening with a solution containing a functional layer material A filling step, a drying step of drying the solution to form a functional layer, and a second electrode disposing step of disposing a second electrode facing the first electrode through the functional layer. And in the functional layer material filling step, the end of the liquid surface of the solution filled in the opening defined by the partition existing in the central portion of the display region is defined by the partition existing in the central portion of the display region. Filled the opening And it is located higher than the position of the end portion of the liquid surface of serial functional layer.

In another aspect, in the functional layer material filling step, the functional layer material is applied to the opening defined by the partition wall present in the peripheral portion of the display region and the opening defined by the partition wall present in the central portion of the display region. A configuration in which an equal amount of each of the contained solutions is filled may be employed.
In another aspect, in the partition forming step, a partition having a first height at a peripheral portion of the display region, and a second height higher than the first height at a central portion of the display region. The structure which forms the partition which has this may be sufficient.
<< Embodiment 1 >>
A schematic configuration of an organic EL element which is a display element according to one embodiment of Embodiment 1 will be described, and a manufacturing method thereof will be described with reference to the drawings.
<Schematic configuration of organic EL element>
FIG. 5 is a cross-sectional view schematically showing a partial cross section of the organic EL element 100 according to one aspect of the first embodiment. As shown in FIG. 5, the organic EL element 100 is an organic EL element in which top emission type organic EL elements 110a, 110b, and 110c each having a light emitting layer for each of RGB are arranged in a matrix.

  A first electrode 102 that is an anode is formed in a matrix on a substrate 101 (hereinafter referred to as “substrate 101”) that is a TFT substrate, and ITO (indium tin oxide) is formed on the first electrode 102. The layer 103 and the hole injection layer 104 are laminated in that order. The ITO layer 103 is laminated only on the first electrode 102, whereas the hole injection layer 104 is formed not only on the first electrode 102 but also over the entire top surface of the substrate 101.

  A first partition 105 is formed on the periphery of the first electrode 102 via a hole injection layer 104, and a region sandwiched between the first partitions 105 is defined as a first opening 220. The functional layer 106 is stacked in the first opening 220. In one embodiment of the present embodiment, the first electrode 102, the ITO layer 103, and the hole injection layer 104 constitute the base layer 111 of the first partition wall 105. In the central portion of the display area, a second partition (not shown) is stacked on the first partition. The second partition will be described later. Furthermore, on the functional layer 106, an electron injection layer 107, a second electrode 108 serving as a cathode, and a sealing layer 109 are adjacent to the organic EL element 110 a beyond the region defined by each first partition wall 105. , 110b, and 110c.

The substrate 101 is, for example, alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, boric acid glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicone resin. Alternatively, an insulating material such as alumina is used as a base material.
The first electrode 102 is made of Ag (silver), APC (silver, palladium, copper alloy), ARA (silver, rubidium, gold alloy), MoCr (molybdenum and chromium alloy), NiCr (nickel and chromium alloy). Alloy) or the like.

The ITO layer 103 is interposed between the first electrode 102 and the hole injection layer 104 and has a function of improving the bonding property between the layers.
The hole injection layer 104 is formed of a material that performs a hole injection function such as metal oxide or metal nitride, for example, WOx (tungsten oxide) or MoxWyOz (molybdenum-tungsten oxide). The hole injection layer 104 extends laterally along the bottom surface of the first partition wall 105.

  The first partition 105 is formed of an insulating organic material such as a resin, such as an acrylic resin, a polyimide resin, a novolac type phenol resin, or the like. The first partition wall 105 is preferably resistant to organic solvents, and may be subjected to an etching process, a baking process, or the like. Therefore, the first partition wall 105 is preferably formed of a material that is not easily deformed or altered by the processes. . The height of the first partition 105 may be selected according to the composition of the functional layer 106 to be filled and the ink characteristics. For example, it may be 0.5 μm or more and 2 μm or less, and more preferably 0.8 μm or more and 1.2 μm or less. Further, by adjusting the content of the liquid repellent contained in the partition material of the first partition 105, the temperature and time of the heat treatment, etc., the size of the liquid repellency on the upper surface and the side wall of the first partition 105 can be controlled. Is possible.

  The functional layer 106 as a light emitting layer is a layer made of RGB organic light emitting materials. Examples of the organic light-emitting material include oxinoid compounds, perylene compounds, coumarin compounds, azacoumarin compounds, oxazole compounds, oxadiazole compounds, perinone compounds, pyrrolopyrrole compounds, naphthalene compounds, anthracenes described in JP-A-5-163488. Compound, fluorene compound, fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative and pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, styryl Compound, butadiene compound, dicyanomethylenepyran compound, dicyanomethylenethiopyran compound, fluoresceinization Product, pyrylium compound, thiapyrylium compound, serenapyrylium compound, telluropyrylium compound, aromatic ardadiene compound, oligophenylene compound, thioxanthene compound, anthracene compound, cyanine compound, acridine compound, metal complex of 8-hydroxyquinoline compound, 2-bipyridine Examples include a metal complex of a compound, a Schiff salt and a group III metal complex, an oxine metal complex, and a rare earth complex.

The electron injection layer 107 has a function of transporting electrons injected from the second electrode 108 to the functional layer 106, and is preferably formed of, for example, barium, phthalocyanine, lithium fluoride, or a combination thereof.
Since it is a top emission type, the second electrode 108 is formed of a light transmissive material, for example, ITO, IZO (indium zinc oxide) or the like.

The sealing layer 109 has a role of preventing the functional layer 106 and the like from being exposed to moisture or air, and is made of, for example, a material such as SiN (silicon nitride) or SiON (silicon oxynitride). Is formed.
5 shows a cross-sectional shape obtained by cutting the substrate 101 in the horizontal direction, but the first partition wall 105 extends along the upper surface of the substrate 101 in the vertical direction (the front and back direction in FIG. 5). . A plurality of first partition walls 105 are arranged over the entire top surface of the substrate 101 (see FIG. 6). The first partition 105 is a cross-shaped pixel partition, and the functional layer 106 is disposed in an opening surrounded by the cross-shaped pixel partition in the vertical and horizontal directions as shown in FIG. . However, the first partition wall 105 may be a line partition wall having a stripe shape in plan view, or may be a staggered arrangement or a honeycomb arrangement.

FIG. 6 is a configuration diagram of a substrate in a state where a partition wall used for an organic EL element is provided according to one aspect of Embodiment 1, and FIG. 6A is a plan view of the substrate (of the substrate 101). It is the block diagram which carried out the surface parallel to the main surface. FIG.6 (b) is sectional drawing which shows the cross section cut by AA of Fig.6 (a). In FIG. 6A, a cross-shaped first partition wall 105 is formed on the substrate 101 over the entire display region having the horizontal X ₀ and the vertical Y ₀ . Of these display areas, the horizontal width is X ₁ and X ₂ , the vertical width is Y ₁ and Y ₂ , and each of the two strip-shaped areas is the peripheral part of the display area (hereinafter referred to as “periphery”). , Abbreviated peripheral edge). The part excluding the peripheral part from the display area is the central part of the display area (hereinafter abbreviated as the central part). As shown in FIG. 6B, a second partition 205 is formed in the central portion so as to be stacked on the first partition 105. Therefore, the height of the partition wall in the central portion is higher than the height of the partition wall in the peripheral portion by the height of the second partition wall 205. The second partition 205 may be made of the same material as the first partition 105. The second partition 205 is formed of an insulating organic material such as resin, for example, an acrylic resin, a polyimide resin, a novolac type phenol resin, or the like. The second partition 205 is preferably resistant to organic solvents, and may be subjected to an etching process, a baking process, or the like. Therefore, the second partition 205 is preferably formed of a material that is not easily deformed or deteriorated with respect to these processes. . A functional layer ink 106 ′ is filled in the second opening 250 formed by the cross-shaped first partition wall 105 and the cross-beam-shaped second partition wall 205. The height of the second partition 205 may be set according to the composition of the functional layer 106 to be filled and the ink characteristics. For example, it may be 0.5 μm or more and 1.0 μm or less, and more preferably 0.5 μm or more and 0.8 μm or less. In addition, the ratio of the height of the second partition 205 to the height of the first partition may be 50% or more and 100% or less. In addition, by adjusting the content of the liquid repellent contained in the partition wall material of the second partition wall 205, the temperature and time of the heat treatment, the size of the liquid repellency on the upper surface and the side wall of the first partition wall 105 can be controlled. Is possible.

Note that this embodiment can also be applied to a bottom emission type. For example, it is possible to apply to a bottom emission type configuration by using a material having excellent light transmittance for the first electrode and using a highly reflective material for the second electrode.
<Method for producing organic EL element>
The manufacturing method of the organic EL element which concerns on this embodiment is demonstrated using drawing.

  7 and 8 are schematic cross-sectional views illustrating the manufacturing process of the method for manufacturing the organic EL element 100 according to one aspect of the first embodiment. The cross section cut in the same position as AA of Fig.6 (a) is shown. In the method for manufacturing the organic EL element according to the present embodiment, a base layer forming step for forming a base layer 111 including a first electrode 102, an ITO layer 103 (not shown), and a hole injection layer 104 on a substrate 101 (FIG. 7). (A)), a first partition forming step for forming the first partition 105 defining the first opening 220 (FIGS. 7A, 7B, and 7C), a second opening in the central portion of the substrate. The second barrier rib forming step for forming the second barrier rib 205 defining 250 on the first barrier rib 105 (FIGS. 7D, 7E and 7F), and the functional layer 106 is formed on the base layer 111. Step of forming functional film (FIGS. 7G and 7H), forming step of second electrode and the like for forming electron injection layer 107, second electrode 108, and sealing layer 109 on functional layer 106 (FIG. 7 (i)).

In addition to the manufacturing process of the constituent elements related to the organic EL element described in one aspect of the first embodiment, there are manufacturing processes corresponding to the constituent elements of various organic EL elements. What is necessary is just to manufacture using a well-known method.
(Underlayer forming process)
After preparing the substrate 101, the first electrode 102 made of a metal material having a thickness of about 150 nm is formed on the substrate 101 by using, for example, a vacuum evaporation method or a sputtering method.

As a constituent material of the substrate 101, known materials such as various glass materials can be used. In addition to Ag (silver), the constituent material of the first electrode 102 is APC (silver, palladium, copper alloy), ARA (silver, rubidium, gold alloy), MoCr (molybdenum and chromium alloy), NiCr (nickel and chromium alloy) or the like can be used.
Next, the ITO layer 103 (not shown) is formed on the first electrode 102 by using, for example, a vacuum deposition method or a sputtering method. As a constituent material of the ITO layer 103, a known metal material such as ITO (indium tin oxide) or IZO (indium zinc oxide) which is a light-transmitting conductive material can be used. The ITO layer 103 is laminated only on the first electrode 102.

Further, the hole injection layer 104 is provided by being laminated on the ITO layer 103 by using, for example, a vacuum evaporation method or a sputtering method. The hole injection layer 104 is formed of a material that performs a hole injection function such as metal oxide or metal nitride, for example, WOx (tungsten oxide) or MoxWyOz (molybdenum-tungsten oxide). Here, the hole injection layer 104 is formed not only on the first electrode 102 or the ITO layer 103 but also on the entire upper surface of the substrate 101. For example, the hole injection layer 104 is formed to extend laterally along the bottom surface of the first partition 105.
(First partition formation step)
In the first partition formation step in the present embodiment, a photosensitive resin material containing a liquid repellent is selected as the partition material constituting the first partition 105, and the first partition 105 is formed using a photolithography method.

Here, as the photosensitive resin material, for example, a known resist material composed of an acrylic resin, a polyimide resin, a phenol resin, or the like can be used. Moreover, as a liquid repellent, well-known liquid repellent materials, such as a fluorine-type compound material, can be used, for example.
(Partition film coating process)
A first partition film 105 ′ containing a partition material is applied and formed on the substrate 101 so as to cover the base layer 111 by using, for example, a spin coating method (FIG. 7A).
(Exposure development process)
A mask 200 is arranged in accordance with the pattern of the first opening 220 defined so that the first electrode 102 is exposed on the substrate 101, and selectively exposed 210 (FIG. 7B).

After the exposure processing, the first partition wall 105 that defines the first opening 220 is formed by etching the first partition film 105 ′ using, for example, an alkaline developer as a non-aqueous developer. (FIG. 7 (c)).
(Heat treatment process)
After the exposure and development, the first partition 105 is subjected to a heat treatment at a temperature of about 200 ° C. to 250 ° C., for example, 200 ° C., thereby evaporating the solvent contained in the first partition 105. Thus, the first partition 105 is completed. At this time, the liquid repellent agent diffused and contained in the partition wall material is thermally diffused toward the surface of the first partition wall film 105 ′ by the heat treatment. Therefore, the concentration of the liquid repellent in the first partition film 105 ′ decreases from the surface toward the inside, and the upper surface of the formed first partition 105 is given liquid repellency compared to its side wall. It can be. Here, by adjusting the content of the liquid repellent contained in the partition wall material, the temperature and time of the heat treatment, the liquid repellency on the upper surface and the side wall of the first partition wall 105 can be controlled. As the liquid repellent, a material in which an acrylic resin is a main component and a fluorinated resin is added can be used.

As described above, the first partition forming step is performed. As a result, the first partition 105 having a maximum height of, for example, about 0.5 μm to 2 μm and an average thickness of about 1.0 μm in a method horizontal to the main surface of the substrate 101 is formed.
Note that the first partition formation step is not limited to the above-described disclosure, and various known techniques for forming the partition can be used. For example, after the partition film application step, a liquid repellent treatment step may be performed in which the formed first partition film 105 ′ is heat-treated at a temperature of about 100 ° C., for example. The lyophobic agent is diffused by the heat treatment, and the lyophobic agent contained in the partition material can be thermally diffused toward the surface of the first partition film 105 ′. In the liquid repellent treatment step, the first partition film 105 ′ is not subjected to a heat treatment. After the heat treatment step, the surface of the first partition 105 is surfaced with a predetermined alkaline solution, water, an organic solvent, or the like. By performing the treatment, it is also possible to adjust the liquid repellency of the upper surface and the side wall of the first partition wall 105. Further, the surface of the first partition 105 is subjected to an irradiation treatment such as fluorine plasma or ultraviolet light to decompose the liquid repellent material (for example, fluorine-based resin) dispersed in the partition, and the first partition 105 It is also possible to adjust the liquid repellency of each of the upper surface and the side wall.
(Second partition wall forming step)
In the second partition forming step in this embodiment, a photosensitive resin material containing a liquid repellent is selected as the partition material constituting the second partition 205 in the same manner as in the first partition forming step, and photolithography is used. A second partition 205 is formed. However, unlike the first partition formation step, the developer used in the development step is an aqueous developer. Here, as the photosensitive resin material, for example, a known resist material containing a cellulose derivative substituted with a water-soluble group such as hydroxypropyl cellulose as a water-soluble polymer of a binder can be used. Moreover, as a liquid repellent, well-known liquid repellent materials, such as a fluorine-type compound material, can be used, for example.
(Partition film coating process)
A second partition film 205 ′ containing a partition material is applied and formed on the first partition 105 by using, for example, a spin coating method (FIG. 7D).
(Exposure development process)
A mask 240 is arranged and selectively selected according to the pattern of the second opening 250 formed in the central portion of the display area of the substrate, which is defined as an opening having the same size as the opening of the first opening 220. Exposure 230 is performed (FIG. 7E). Here, the mask 240 is aligned so that the peripheral edge of the bottom of the second opening 250 is the same position as the peripheral edge of the bottom of the first opening 220 in a plan view (a surface parallel to the main surface of the substrate 101). To do.

After performing the exposure process, the second partition wall 205 ′ defining the second opening 250 in the central portion of the substrate is etched on the first partition 105 by etching the second partition film 205 ′ using an aqueous developer. (FIG. 7F).
(Heat treatment process)
After the exposure and development, the second partition 205 is subjected to heat treatment at a temperature of about 200 ° C. to 250 ° C., for example, 200 ° C., thereby evaporating the solvent contained in the second partition. Thus, the second partition 205 is completed. At this time, the liquid repellent agent diffused in the baking process and contained in the partition wall material is thermally diffused toward the surface of the second partition wall film 205 ′ by the heat treatment. Therefore, the concentration of the liquid repellent in the second partition film 205 ′ decreases from the surface toward the inside, and the upper surface of the formed second partition 205 is given liquid repellency compared to its side wall. It can be. Here, by adjusting the content of the liquid repellent contained in the partition wall material, the temperature and time of the heat treatment, the liquid repellency on the upper surface and the side wall of the second partition wall 205 can be controlled. As the liquid repellent, a material in which an acrylic resin is a main component and a fluorinated resin is added can be used.

As described above, the second partition forming step is performed. As a result, the second partition wall 205 having a maximum height of, for example, about 0.5 μm to 1.0 μm and an average thickness of about 0.5 μm in the direction horizontal to the main surface of the substrate 101 is formed.
Note that the second partition formation step is not limited to the above disclosure, and various known techniques for forming the partition can be used in the same manner as the first partition formation step. For example, there is a method using a halftone mask. Further, after the partition film application step, a liquid repellent treatment step may be performed in which the formed first partition film 205 ′ is subjected to a heat treatment at a temperature of about 100 ° C., for example. The lyophobic agent is diffused by the heat treatment, and the lyophobic agent contained in the partition wall material can be thermally diffused toward the surface of the first partition wall film 205 ′. In addition, as a liquid repellent treatment step, the surface of the second partition 205 is subjected to irradiation treatment such as fluorine plasma and ultraviolet rays, so that the liquid repellent material (for example, fluorine resin) dispersed in the partition is decomposed. Thus, the liquid repellency of each of the upper surface and the side wall of the second partition wall 205 can be adjusted. Further, by increasing the content of the liquid repellent agent contained in the partition wall material of the second partition wall as compared with that of the partition wall material of the first partition wall, the side wall of the first partition wall, the side wall of the second partition wall, the first partition wall The liquid repellency can be increased in the order of the upper surface of the first partition wall and the upper surface of the second partition wall.

In the drawing, the first partition 105 and the second partition 205 have a quadrangular cross section, but the actual shape of the partition is that the side walls and the upper surface of the partition bulge outward in a gentle curve. It is easy to become a thing. Moreover, the opening part which a partition prescribes | regulates tends to become a thing gradually expanded toward the upper side. Therefore, the height of the partition is based on the maximum height as described above, and the thickness in the direction horizontal to the main surface of the substrate is used based on the average thickness. In addition, for example, if the property that the opening defined by the partition wall tends to be gradually increased in diameter toward the upper side is used, the position of the peripheral edge of the bottom of the second opening defined by the second partition wall in plan view The opening area of the second opening can be easily adjusted at any height by arranging it at the same position as the position of the peripheral edge of the bottom of the first opening defined by the first partition wall or at a position retracted from it. The size of the opening area of the first opening can be larger.
(Functional film deposition process)
A functional material constituting the functional layer 106 defined in accordance with the use of the organic EL element and a solvent are mixed at a predetermined ratio to prepare a conductive organic functional film ink. The ink is dropped from the ink head 260 as ink droplets from the openings of the first opening 220 and the second opening 250 using the ink jet method, and functions to cover the exposed region of the base layer 111. The layer ink 106 ′ is applied (FIG. 7G). Here, it is desirable to fill the second opening 250 in the central portion and the first opening 220 in the peripheral portion with an equal amount of ink. By filling the first opening 220 and the second opening 250 with an equal amount of ink, the functional film forming process can be easily performed. Furthermore, an equal amount of functional film constituent material can be filled in the pixels formed by the first opening 220 and the second opening 250. And the functional layer 106 is formed by evaporating and drying the solvent contained in the functional layer ink 106 ′ and heating and baking as necessary (FIG. 7 (h)).

Here, the functional layer 106 is formed as a surface shape covering the exposed surface of the underlayer 111, but the amount of ink droplets to be dropped, the processing atmosphere and processing time for evaporating and drying the solvent, and heating and baking. The film shape of the functional film can be adjusted by appropriately adjusting the processing temperature, the processing time, and the like.
(Charge injection layer, second electrode, sealing layer forming step)
An electron injection layer 107, a second electrode 108 made of a metal material, and a sealing layer 109 are sequentially formed on the functional layer 106 by using, for example, a vacuum evaporation method or a sputtering method.

 As a constituent material of the electron injection layer 107, for example, barium, phthalocyanine, lithium fluoride, or a combination thereof can be used. As a constituent material of the second electrode 108, a single metal material such as Al, or a known metal material such as ITO (indium tin oxide) or IZO (indium zinc oxide) which is a light-transmitting conductive material can be used. As a constituent material of the sealing layer 109, for example, a material such as SiN (silicon nitride) or SiON (silicon oxynitride) can be used.

The manufacturing method of the organic EL element of one embodiment of the first embodiment is configured by the steps as described above.
In the manufacturing method shown in one embodiment of the present embodiment, after the first partition film 105 ′ is applied in the partition film coating process, the first partition 105 is formed by the exposure development process, and then the partition film coating is performed. After applying the second partition film 205 ′ in the process, the first partition 105 is formed by the exposure and development process. However, the method of forming the partition is not limited to this method. For example, after applying the first barrier rib film 105 ′, only exposure according to the pattern of the barrier rib film 105 ′ is performed. Next, after applying the second barrier rib film 205 ′, the pattern of the first barrier rib film 205 ′ is applied. A method of performing combined exposure and finally forming the first partition 105 and the second partition 205 by a development process may be used. Or after apply | coating 1st partition film | membrane 105 ', 2nd partition film | membrane 205' is apply | coated, Then, exposure matched with the pattern of 1st partition film 105 ', and it matched with the pattern of 2nd partition film 205'. The exposure may be performed continuously by changing the wavelength or light intensity, and finally the first partition 105 and the second partition 205 may be formed by a development process.
<Example>
Next, in the example of the organic EL element of one embodiment of Embodiment 1, it was confirmed that a film shape similar to the peripheral portion of the display region can be formed in the central portion of the display region of the substrate. The effects will be described with reference to the drawings. The organic EL device according to the example was created by the manufacturing method described with reference to FIGS. The first partition 105 has a height of about 1.0 μm, the second partition has a height of 0.5 μm and 1.0 μm, and 0 μm is a comparative example. The functional layer 106 was formed by filling the openings with an equal amount of ink for all the pixels in the application region using an inkjet method in the openings defined by the partition walls. Subsequently, the ink was dried under a reduced pressure of 10 Pa or less, and then baked at about 200 ° C.
(Ink pinning position, film thickness evaluation test)
FIG. 9 is a cross-sectional view showing the relationship between the height of the partition wall and the ink pinning position in the central portion of the display area in an example of the organic EL element according to one aspect of the embodiment. The partition height here refers to the total height of the first partition 105 and the second partition 205 in FIG. Here, in FIGS. 9A, 9 </ b> B, and 9 </ b> B, the thick line in the figure indicates the experimental result of measuring the cross-sectional profile of the functional layer, and the thin line indicates the experimental result of measuring the cross-sectional profile of the partition wall. .

 From FIG. 9, when the partition wall height is increased to about 1.0 μm, about 1.5 μm, and about 2.0 μm (actual values are 1.03 μm, 1.53 μm, and 1.95 μm, respectively), after firing The ink pinning positions, which are the positions of the end portions on the upper surface of the functional layer, were 0.655 μm, 0.930 μm, and 1.260 μm, respectively, and it was confirmed that the height increased as the partition wall height increased.

FIG. 10 is an example of the organic EL element according to one aspect of the embodiment, and is a cross-sectional view illustrating a change in the cross-sectional profile of the functional film when the height of the partition wall is changed in the central portion of the display region. . Here, the height of the partition wall refers to the total height of the first partition wall 105 and the second partition wall 205 in FIG.
From FIG. 10, when the height of the partition wall is increased to about 1.0 μm, about 1.5 μm, and about 2.0 μm (actual values are 1.03 μm, 1.53 μm, and 1.95 μm, respectively), after firing The film thicknesses at the center of the second opening 250 of the functional layer (position where the horizontal axis in FIG. 10 is 0) are about 71 μm, about 63 μm, and about 47 μm, respectively, and decrease as the height of the partition increases. Confirmed to do. In addition, from FIG. 10, when the height of the partition is increased to about 1.0 μm, about 1.5 μm, and about 2.0 μm, the thickness of the functional layer in the side wall portion of the partition of the functional layer after firing is as follows. It was confirmed that the height increased with the increase in height.

 FIG. 11 is a cross-sectional view showing a change in the cross-sectional profile of the functional film in the peripheral portion of the display area of the example of the organic EL element according to one aspect of the embodiment. The partition height here refers to the height of the first partition 105. From FIG. 11, when the partition wall height is about 1.0 μm, the film thickness at the center of the first opening 220 of the functional layer after firing (position where the horizontal axis in FIG. 10 is 0) is about 54 μm. I confirmed that there was.

  From the above, when the partition wall height in the peripheral portion is about 1.0 μm, the height of the partition wall in the central portion is about 1.5 μm and about 2.0 μm, so that the functional layer after firing that has been conventionally 17 μm The difference between the peripheral portion and the central portion of the film thickness at the center of the opening could be reduced to about 9 μm and about 7 μm, respectively, as absolute values. In this embodiment, if the height of the central partition wall is about 1.7 μm, the film thickness can be the same as that of the peripheral portion.

 As described above, in the organic EL element according to one aspect of the embodiment, in the organic EL element in which the functional film is formed over the substrate by a wet process using a discharge device that discharges liquid such as ink and functional liquid. By increasing the ink pinning position in the pixel in the central part of the display area and increasing the film thickness near the side wall, the difference in the film thickness of the functional film between the central part and the peripheral part of the display area can be improved. it can.

The numerical values, dimensions, and film thickness described above are conditions relating to the organic EL element according to one aspect of the embodiment, and the embodiment of the present invention is not limited to this. The thickness of the functional film, the height of the partition walls, the difference in the height of the partition walls between the central part and the peripheral part, etc. are the size of the display area, the material composition of the functional film, the composition and viscosity of the ink, the drying temperature and time, the drying Depending on the conditions of the atmosphere, etc., it can be appropriately selected depending on the specifications and conditions of the organic EL element to be used.
<< Embodiment 2 >>
<Schematic configuration of organic EL element, manufacturing method>
Next, an organic EL element according to one embodiment of Embodiment 2 will be described. The organic EL element is different from the first embodiment only with respect to the partition walls, and the other configurations are the same as those of the first embodiment, and thus description thereof is omitted.

Also in the organic EL element according to the second embodiment, as in the organic EL element according to the first embodiment, the central portion and the peripheral portion of the display region on the substrate shown in FIG. Is defined as In the organic EL element according to the second embodiment, as shown in FIG. 6A, stripe-like partition walls are formed on the substrate 101 over the entire display region having the horizontal X ₀ and the vertical Y _0. Yes. Of these display areas, the horizontal width is X ₁ and X ₂ , the vertical width is Y ₁ and Y ₂ , and each of the two strip-shaped areas is the peripheral part of the display area (hereinafter referred to as “periphery”). , Abbreviated peripheral edge). The part excluding the peripheral part from the display area is the central part of the display area (hereinafter abbreviated as the central part).

 FIG. 12 is a cross-sectional view schematically showing a partial cross section of an organic EL element according to one aspect of the second embodiment. A third partition 305 is formed on the periphery of the first electrode 102 with a hole injection layer 104 interposed therebetween, and a region sandwiched between the third partitions 305 is defined as a first opening 220. The functional layer 106 is stacked in the first opening 220. In one embodiment of the present embodiment, the first electrode 102, the ITO layer 103, and the hole injection layer 104 constitute the base layer 111 of the third partition 305.

 The third partition 305 is formed of an insulating organic material such as a resin, for example, an acrylic resin, a polyimide resin, a novolac type phenol resin, or the like, like the first partition 105 of the first embodiment. The third partition 305 is preferably resistant to organic solvents, and may be subjected to an etching process, a baking process, or the like. Therefore, the third partition 305 is preferably formed using a material that is not easily deformed or deteriorated by the processes. . The height of the third partition 305 may be selected according to the composition of the functional layer 106 to be filled and the ink characteristics. For example, it may be 0.5 μm to 2 μm, more preferably 0.8 μm to 1.2 μm.

 By adjusting the content of the liquid repellent contained in the partition wall material of the third partition 305, the temperature and time of the heat treatment, etc., the size of the liquid repellency on the upper surface and the side wall of the third partition 305 can be controlled. is there. In addition, the surface of the third partition 305 is subjected to irradiation treatment such as fluorine plasma and ultraviolet rays, so that the liquid repellent material (for example, fluorine-based resin) dispersed in the partition is decomposed and the third partition 305 is decomposed. It is also possible to adjust the liquid repellency of each of the upper surface and the side wall.

 The organic EL element according to Embodiment 2 adopts a configuration in which the liquid repellency in the vicinity of the partition head is different between the central portion and the peripheral portion of the display region. Specifically, a liquid repellent process is performed in the vicinity of the top of the third partition wall 305 in the peripheral portion of the display area, which is indicated by D in FIG. A liquid repellent treatment was performed by performing a fluorine plasma treatment on the range indicated by D in FIG. The range D in which the liquid repellency treatment is performed to adjust the liquid repellency of the upper surface and the side wall of the third partition wall 305 is determined by the ink pinning position P1 of the peripheral portion. The ink pinning position P1 of the peripheral portion is substantially the same as the thickness of the functional layer 106 in the central portion with respect to the ink pinning position P2 of the functional layer 106 after baking in the central portion. It can be determined as follows.

 Specifically, the ink pinning position P1 in the second embodiment may be determined to be substantially the same as the ink pinning position P1 in the first embodiment. For example, the liquid repellent treatment is performed on the top of the third partition 305 and the range of the side of the third partition 305 along the opening from the top to a position about 0.5 μm to 1.0 μm in the direction of the substrate 101. Can be applied. However, the present invention is not limited to this, and the range D in which the liquid repellent treatment is performed includes the thickness of the functional film, the height of the partition walls, and the difference in the height of the partition walls between the central portion and the peripheral portion. It depends on the size of the region, the material composition of the functional film, the composition and viscosity of the ink, the drying temperature and time, the conditions of the drying atmosphere, etc.

As described above, in the organic EL element according to one aspect of the second embodiment, the organic EL element in which the functional film is formed on the substrate by the wet process using the discharge device that discharges the liquid such as the ink and the functional liquid. In order to improve the difference in the film thickness of the functional film between the central part and the peripheral part of the display area by increasing the ink pinning position in the pixel in the central part of the display area and increasing the film thickness near the side wall. Can do.
≪Summary≫
As described in the embodiment, in the organic EL element according to one aspect of the embodiment, the organic EL in which a functional film is formed over the substrate by a wet process using a discharge device that discharges liquid such as ink and functional liquid. In the device, by increasing the ink pinning position in the pixel in the central portion of the display area and increasing the film thickness in the vicinity of the side wall, the functional film film between the central portion and the peripheral portion of the display area that causes luminance unevenness Thickness difference can be improved.

 The present invention is not limited to the embodiment described above. For example, in the embodiment, the organic light emitting layer and the organic semiconductor layer are exemplified as the functional film. However, the functional film of the present invention is not limited to this, and covers all functional films that can be applied by a wet process. Examples of the functional film of the organic EL element include an organic light emitting layer, a buffer layer, a hole transport layer, a hole injection layer, an electron injection layer, and an electron transport layer.

In the embodiment, the top emission type display element is described, but the present invention can be applied to a bottom emission type. For example, it is possible to apply to a bottom emission type configuration by using a material having excellent light transmittance for the first electrode and using a highly reflective material for the second electrode.
In the embodiment, the ink dropping device using the piezo-type inkjet head that ejects ink by the volume change of the piezoelectric element has been described. However, the thermal inkjet method that ejects ink by the electrothermal transducer is used. May be. Further, as the ink discharge means of the ink application device, a dispenser system that discharges ink onto the substrate continuously may be used.

In order to facilitate understanding of the invention, the scales of the components shown in the above-described embodiments may differ from actual ones. The present invention is not limited by the description of each of the above embodiments, and can be appropriately changed without departing from the gist of the present invention.
In addition, there are members such as electrode lead wires in the organic EL display panel, but various aspects can be implemented based on ordinary knowledge in the technical field of light emitting elements, display devices, etc. for electrical wiring and electrical circuits. Since it is not directly relevant to the description of the present invention, the description is omitted. Each figure shown above is a schematic diagram, and is not necessarily illustrated strictly.

  The present invention is applied to a light emitting element using a functional layer using an ink discharge device or the like, and a manufacturing method thereof.

DESCRIPTION OF SYMBOLS 100 Display element 101 Substrate 102 1st electrode 103 ITO layer 104 Hole injection layer 105 1st partition 106 Functional layer 107 Electron injection layer 108 2nd electrode 109 Sealing layer 111 Underlayer 205 2nd partition 220 1st opening part 250 2nd Opening 305 Third partition

Claims (9)

A display element having a display region in which a plurality of pixels are arranged in a matrix,
A substrate on which a base layer including a first electrode is laminated;
A partition wall located on the underlayer and defining an opening;
A functional layer located above the underlayer and within the opening;
A second electrode facing the first electrode through the functional layer,
The end of the upper surface of the functional layer in the pixel existing in the central portion of the display region is positioned higher than the end of the upper surface of the functional layer in the pixel existing in the peripheral portion of the display region.  The display element according to claim 1, wherein a partition wall in a pixel existing in a central portion of the display region is higher than a partition wall in a pixel existing in a peripheral portion of the display region.  The liquid repellency of the portion above the portion of the side surface of the partition wall in the pixel located in the peripheral portion of the display area and above the end portion of the upper surface of the functional layer formed in the opening defined by the partition wall is The display element according to claim 1, wherein the liquid repellency of a corresponding partition wall portion in the center of the display region is higher.  The display element according to claim 1, wherein the partition walls in the pixels existing in the peripheral portion of the display area have a height of 0.5 μm or more and 1.0 μm or less and the height of the partition walls is higher than the partition walls in the pixel existing in the central part of the display area. .   The display area has a square shape, and a peripheral portion of the display area is parallel to one side of the square and the one side located on the center side of 5% of the length of the other side adjacent to the one side. The display element according to claim 1, wherein the display element is in a range between the lines.  The liquid repellency of the top part of the partition wall in the pixel existing in the peripheral part of the display area is higher than the liquid repellency of the side part of the partition wall in the pixel existing in the central part of the display area at the same height as the top part of the display area. The display element according to claim 2, which is high. A method for manufacturing a display element having a display region in which a plurality of pixels are arranged in a matrix,
A base layer forming step of disposing a base layer including a first electrode on the substrate;
A partition forming step of forming a partition defining an opening on the underlayer; and
A functional layer material filling step of filling the opening with a solution containing the functional layer material;
A drying step of drying the solution to form a functional layer;
A second electrode disposing step of disposing a second electrode facing the first electrode through the functional layer;
In the functional layer material filling step, the end of the liquid surface of the solution filled in the opening defined by the partition existing in the central portion of the display region is the opening defined by the partition existing in the central portion of the display region. It is located higher than the position of the end of the liquid surface of the functional layer filled,
A method for manufacturing a display element. In the functional layer material filling step, an equal amount of the solution containing the functional layer material is filled in each of the opening defined by the partition existing in the peripheral portion of the display region and the opening defined by the partition existing in the central portion of the display region. The manufacturing method of the display element of Claim 7. In the partition formation step, a partition having a first height at a peripheral portion of the display region and a partition having a second height higher than the first height are formed at a central portion of the display region.
The manufacturing method of the display element of Claim 7.

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