JP5974245B2 - Organic EL device and manufacturing method thereof - Google Patents

Description

  The present invention relates to an organic EL element and a method for manufacturing the same, and more particularly to a technique for suppressing generation of a non-formed region of a functional layer.

  An organic EL element is a current-driven light-emitting element, in which an organic light-emitting layer containing an organic light-emitting material, and a functional layer such as a hole transport layer and a buffer layer are disposed between an electrode pair consisting of an anode and a cathode. It has a structure. During driving, a voltage is applied between the electrode pairs, and an electroluminescence phenomenon generated by recombination of holes injected from the anode to the organic light emitting layer side and electrons injected from the cathode to the organic light emitting layer side is utilized. Since the organic EL element emits light by itself, the organic EL element has high visibility, and since it is a completely solid element, it has characteristics such as excellent impact resistance.

Organic EL elements are roughly classified into two types depending on the material of the functional layer.
The first is an evaporation type organic EL element formed by forming a film of an organic low molecular material by a vacuum process such as an evaporation method.
Secondly, a coating type organic EL in which an organic polymer material or an organic low molecular weight material having a good thin film formability is formed by a wet process such as an ink jet method or a gravure printing method to form a hole transport layer or an organic light emitting layer. It is an element.

At present, an organic EL display panel in which a coating type organic EL element is used as a light emitting unit and a plurality of organic EL display panels are arranged on a substrate in a matrix direction has been developed as a display or an image display device of an electronic device.
In the manufacturing process of an organic EL element, when a functional layer such as an organic light emitting layer is disposed on a substrate, it is required to appropriately dispose a functional material serving as a material for the functional layer in a predetermined region on the substrate. For this reason, for example, in the manufacturing process of a coating type organic EL element, measures are taken to make liquid repellency in advance in a region where the functional layer on the substrate surface is not formed, and to make it difficult for ink containing a functional material to adhere to this region. Yes.

JP 2010-244868 A

However, in the conventional manufacturing process of the organic EL element, the functional layer may not be appropriately formed in the predetermined region.
If the functional material is not properly disposed in the predetermined region, an organic EL element including a region where the functional layer is not formed is manufactured. In the organic EL element including such an unformed region, the light emission characteristics may be significantly deteriorated due to a problem such as a short circuit occurring in the unformed region during driving.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic EL element that can be expected to have good light emission characteristics by appropriately disposing a functional material on a substrate and a method for manufacturing the same. And

  In order to solve the above problems, a method for manufacturing an organic EL element according to one embodiment of the present invention includes a first electrode forming step of forming a first electrode above a substrate, and an energy beam above the substrate. A reflection film forming step for forming a reflection film having reflection characteristics, and an opening having an inner periphery surrounded by the slope portion, and having transparency to the energy rays and a liquid repellent component A partition wall forming step of forming a partition wall containing the reflective film so that the reflective film is located in a portion corresponding to the slope portion when the substrate surface is viewed in plan, and irradiating the energy beam from above the substrate, Liquid repellency of the surface of the partition wall in at least a part of the inclined surface portion of the opening by the incident light of the energy beam to the light beam and the reflected light of the energy beam transmitted through the partition wall and reflected by the reflective film A functional layer that forms a functional layer above the substrate by disposing a surface treatment step that lowers and disposing a functional material inside the opening so as to be in contact with the partition wall surface having the reduced liquid repellency It is assumed that a formation step and a second electrode formation step for forming a second electrode above the functional layer are performed.

  In the method for manufacturing an organic EL element according to one aspect of the present invention described above, a reflective film having a reflection characteristic with respect to energy rays is disposed on the substrate, and the substrate has transparency to the energy rays. The partition walls are formed using the material having liquid repellency while the openings are present. Here, the reflection film is disposed so as to be located in a portion corresponding to the slope portion of the opening when the substrate is viewed in plan.

  With this contrivance, in the surface treatment step of irradiating the substrate with energy rays, the incident light of the energy rays and the reflected light of the energy rays that have been transmitted through the partition walls and reflected by the reflective film are applied to the partition wall surfaces on the slopes of the openings. Both are irradiated and decomposed by energy rays rich in liquid repellent components. As a result, the liquid repellency is effectively reduced on the surface of the partition wall of the slope portion. Therefore, when the functional layer is formed by bringing the functional material into contact with the inside of the opening portion, the functional material is excellent against the slope portion. Can be contacted with wettability. As a result, it is possible to prevent the generation of the functional layer unformed region in the vicinity of the slope portion in the opening.

  Therefore, in the method for manufacturing an organic EL element in one embodiment of the present invention, it can be expected that a functional layer is appropriately formed on a substrate to manufacture an organic EL element having good light emission characteristics.

3 is a partial cross-sectional view showing a schematic configuration of an organic EL element 100G according to Embodiment 1. FIG. 1 is a front view of an organic EL display panel 10 showing an arrangement of organic EL elements 100R, 100G, and 100B. It is a figure which shows an example of the manufacturing process of the organic EL element 100G. It is a figure which shows an example of the manufacturing process of the organic EL element 100G. It is a figure which shows an example of the manufacturing process of the organic EL element 100G. It is a figure which shows the change of the contact angle of the functional material of the partition surface before and behind UV irradiation of an Example (with a reflecting film) and a comparative example (without a reflecting film). It is a photograph which shows the result of having observed the unformed area | region of the organic layer material at the time of performing a UV irradiation process to a comparative example (without reflection film). It is a photograph which shows the result of having observed the unformed area | region of the organic layer material at the time of performing an UV irradiation process to an Example (with a reflecting film). It is a graph which shows the measurement result of the non-formation area | region which generate | occur | produced in the comparative example (without reflection film). It is a graph which shows the difference in the wettability of the partition of each element of a top emission type and a bottom emission type. 6 is a partial cross-sectional view showing a schematic configuration of an organic EL element 100G1 according to Embodiment 2. FIG. It is a fragmentary sectional view which shows schematic structure of the organic EL element 100R2, 100G2, 100B2 which concerns on Embodiment 3. FIG.

<Aspect of implementation>
A method for manufacturing an organic EL element according to an aspect of the present invention includes: a first electrode forming step of forming a first electrode above a substrate; and a reflective film having reflection characteristics with respect to energy rays above the substrate. A barrier film containing a liquid-repellent component that is permeable to the energy rays while having an opening whose inner periphery is surrounded by the inclined surface, A partition forming step for forming the reflective film so that the reflective film is positioned on the sloped portion when the surface is viewed in plan, and the energy beam is irradiated from above the substrate, and the incident light of the energy beam to the partition And a surface treatment step that reduces the liquid repellency of the partition wall surface at least at a part of the inclined surface portion of the opening by the reflected light of the energy beam that has been transmitted through the partition wall and reflected by the reflective film. And a functional layer forming step of forming a functional layer above the substrate by disposing a functional material inside the opening so as to be in contact with the partition wall surface having reduced liquid repellency; A second electrode forming step for forming a second electrode is provided above the functional layer.

Here, as another aspect of the present invention, ultraviolet rays can be used as the energy rays in the surface treatment step.
As another aspect of the present invention, the reflective film formed in the reflective film forming step may have a reflectivity with respect to ultraviolet rays of 50% or more and 90% or less.
As another aspect of the present invention, in the reflective film forming step, the reflective film can be formed using at least one of aluminum, an aluminum alloy, rhodium, and a rhodium alloy.

As another aspect of the present invention, in the functional layer forming step, ink containing the functional material can be applied to the inside of the opening.
As another aspect of the present invention, the functional material may be an organic light emitting material, and the functional layer may be an organic light emitting layer.
As another aspect of the present invention, the functional material may be a hole transport layer material, and the functional layer may be a hole transport layer.

Moreover, as another aspect of the present invention, an angle between the surface of the slope portion at the periphery of the opening and the surface of the substrate in the opening can be an obtuse angle.
As another aspect of the present invention, a transparent substrate is used as the substrate. In the first electrode forming step, the first electrode is formed using a transparent conductive material, and in the second electrode forming step, visible light is used. The second electrode can also be formed using a conductive material having reflection characteristics.

As another aspect of the present invention, in the reflecting film forming step, the reflecting film can be formed on the upper surface of the first electrode.
As another aspect of the present invention, in the first electrode forming step, the first electrode is formed using a conductive material having visible light reflection characteristics, and in the second electrode forming step, a transparent conductive material is used. It is also possible to form the second electrode.

As another aspect of the present invention, the reflective film may be formed in at least a partial region around the first electrode on the substrate.
As another aspect of the present invention, when the substrate surface is viewed in plan, the opening has a shape in which the first direction is a major axis and the second direction intersecting the first direction is a minor axis, In the reflective film forming step, the reflective film may be formed so as to be positioned at a portion corresponding to the inclined surface at least one of both ends of the opening along the first direction.

An organic EL element which is one embodiment of the present invention includes a substrate, a first electrode provided above the substrate, a reflective film having a reflection characteristic with respect to energy rays, provided above the substrate,
When the surface of the substrate is viewed in plan, the opening is surrounded by the inclined surface so that the reflective film is located in a portion corresponding to the inclined surface. And a partition formed to contain a liquid repellent component, a functional layer formed inside the opening above the substrate, and a second electrode formed above the functional layer, And the liquid repellency of the surface of the first partition in at least a part of the peripheral edge of the opening is lower than the liquid repellency of the surface of the second partition other than the surface of the first partition, and the functional layer is Suppose that it is formed in contact with the surface of the first partition wall.

Here, as another aspect of the present invention, the reflective film may be made of a material having a reflectance with respect to ultraviolet rays of 50% or more and 90% or less.
As another aspect of the present invention, the reflective film may be configured to use at least one of aluminum, an aluminum alloy, rhodium, and a rhodium alloy.
As another aspect of the present invention, the functional material may be an organic light emitting material, and the functional layer may be an organic light emitting layer.

As another aspect of the present invention, the functional material may be a hole transport layer material, and the functional layer may be a hole transport layer.
As another aspect of the present invention, the angle between the surface of the slope portion at the periphery of the opening and the substrate surface in the opening may be an obtuse angle.
As another aspect of the present invention, the substrate may be transparent, the first electrode may be made of a transparent conductive material, and the second electrode may be made of a conductive material having visible light reflection characteristics. it can.

As another aspect of the present invention, the first electrode may be made of a conductive material having visible light reflection characteristics, and the second electrode may be made of a transparent conductive material.
According to another aspect of the present invention, there is provided an organic EL display panel in which the organic EL elements according to any one of the aspects of the present invention are arranged in a plurality of planes along a first direction and a second direction intersecting each other. To do.
<Background of the invention>
In the manufacturing process of the coating type organic EL element, the inventors of the present application have examined the cause of the generation of the functional layer non-formation region. As a result, the liquid repellent property of the partition wall surface at the slope portion of the opening contacting the ink containing the functional material. It was confirmed that the effect of decomposing and removing the liquid repellent component was not sufficiently obtained in the surface treatment step of irradiating the substrate surface with energy rays in order to decompose and remove the active component.

  In particular, when a conventional bottom emission type coating-side organic EL element is manufactured, the first electrode, the substrate, and the partition are all transparent. In this case, in the surface treatment step, when energy rays such as UV light are irradiated from the upper surface of the substrate, most of the energy rays pass through the first electrode, the substrate, the partition walls, and the like. For this reason, it was ascertained that the liquid repellent component on the partition wall surface of the sloped portion in contact with the ink could not be sufficiently removed.

Therefore, in the method for manufacturing an organic EL element according to one aspect of the present invention, when the substrate is viewed in plan, the reflection characteristic with respect to the energy rays is adjusted to a portion corresponding to the inclined surface provided on the inner periphery of the opening above the substrate. A reflective film having the following is formed.
With this contrivance, in the surface treatment step, abundant energy rays from both incident light of energy rays and reflected light from the reflecting film are irradiated to the partition wall surface in the upper slope corresponding portion provided with the reflecting film. As a result, the effect of decomposing and removing the liquid repellent component on the partition wall surface can be enhanced.

As a result, the functional layer can be formed by adhering the ink containing the functional material to the slope portion from which the water-repellent component has been appropriately decomposed and removed. Therefore, it is possible to suppress the occurrence of an area where the functional layer is not formed in the vicinity of the slope portion. Therefore, it is possible to manufacture an organic EL element having good light emission characteristics by suppressing the occurrence of a short circuit due to an unformed region of the functional layer during driving.
In the surface treatment step, the energy beam irradiation time for removing the liquid-repellent component on the partition wall surface of the slope portion is reduced by using the reflected light of the energy beam by using the reflective film disposed on the substrate. You don't have to hang it. For this reason, it is possible to suppress the damage (thermal damage, etc.) of the components on the substrate due to the long-time energy beam irradiation, and to achieve a long life of the organic EL element and a favorable continuous driving in a high temperature environment. .
<Embodiment 1>
(Organic EL display panel 10)
FIG. 1 is a partial cross-sectional view showing one pixel of the organic EL display panel 10. FIG. 2 is a partial front view showing one pixel of the organic EL display panel 10.

  In the organic EL display panel 10, organic EL elements 100 </ b> R, 100 </ b> G, and 100 </ b> B having emission colors of red (R), blue (B), and green (G) are divided into banks (partition walls) 5. Arranged along the X direction. Each of the organic EL elements 100R, 100G, and 100B constitutes a subpixel. As shown in FIG. 2, three adjacent organic EL elements 100R, 100G, and 100B constitute one pixel (pixel) as a set.

A bus bar (auxiliary wiring) region may be provided along the X direction, for example, for each pixel or every several pixels.
As shown in FIG. 1, an organic EL display panel 10 includes a TFT substrate 1 (hereinafter simply referred to as “substrate 1”), a first electrode (here, an anode) 2 stacked in the same order on the upper surface thereof, and And a reflective film 3 and a hole injection layer 4. Further, on the hole injection layer 4, a hole transport layer (IL layer) 6 A, an organic light emitting layer 6 B, an electron transport layer 7, a cathode 8, and a sealing layer 9 are provided between adjacent banks 5. .

  The anode 2, the reflective film 3, the hole transport layer 6A, and the organic light emitting layer 6B are individually formed for each of the organic EL elements 100R, 100G, and 100B. The hole injection layer 4, the electron transport layer 7, the cathode 8, and the sealing layer 9 are uniformly formed over the entire surface of the substrate 1. Here, the substrate 1 and the anode 2 are made of a transparent material, and the cathode 2 is made of a visible light reflecting material, whereby the organic EL elements 100R, 100G, and 100B are made as a bottom emission type.

The usage form of the organic EL display panel 10 can be a part of a television system combined with an audio device. The organic EL display panel 10 does not require a backlight unlike a liquid crystal display (LCD) and is suitable for thinning, and exhibits excellent characteristics from the viewpoint of system design design.
Hereinafter, each component of the organic EL elements 100R, 100G, and 100B will be described.
[Substrate 1]
The substrate 1 is a portion serving as a base material for the organic EL elements 100R, 100G, and 100B, and a transparent TFT wiring portion is formed on the surface of the substrate body. The substrate body is, for example, alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, polyethylene, polyester, silicon resin Or an insulating material such as alumina.
[Anode 2]
The anode 2 is an electrode for supplying holes to the organic light emitting layer 6B side. In Embodiment 1, the organic EL elements 100R, 100G, and 100B have a bottom emission structure, so that the anode 2 is formed of a transparent conductive material, for example, a thin film such as IZO or ITO.
[Reflection film 3]
The reflective film 3 is one of the main features in the first embodiment, and is made of a material having reflectivity with respect to an energy ray such as UV, for example, aluminum or an aluminum alloy (ACL or the like).

Here, in FIG. 2, the arrangement position of the reflective film 3 when the substrate 1 is viewed in plan is indicated by a dotted line. As shown in FIG. 2, the reflective film 3 is provided in an annular shape in accordance with a position corresponding to the slope portion 5c sandwiched between the upper end portion 5a and the lower end portion 5b of the bank 5 when the substrate 1 is viewed in plan view. Here, considering the placement margin, as an example, the inner end 3 b of the reflective film 3 is overlapped with the lower end 5 b of the bank 5, and the outer end 3 a of the reflective film 3 is extended slightly outside the upper end 5 a of the bank 5. Provided. Such a reflective film 3 is provided for the purpose of reflecting the incident light of the energy beam incident on the bank 5 upward in the surface treatment step of irradiating the energy beam onto the substrate 1 at the time of manufacture.
[Hole injection layer 4]
The hole injection layer 4 is disposed for the purpose of increasing injection efficiency when holes are injected into the organic light emitting layer 6B side, and is made of a transparent thin film made of, for example, a transition metal oxide.
[Bank 5]
The bank 5 is made of a transparent insulating material and has a stripe structure having a certain trapezoidal (tapered) cross section on the surface of the hole injection layer 4 in the presence of the openings 101R, 101G, and 101B partitioning the subpixels. It is formed so as to form a well structure. The inner periphery of the openings 101R, 101G, and 101B is surrounded by the slope portion 5c. The slope part 5c is inclined from the upper end part 5a to the lower end part 5b, and the angle between the openings 101R, 101G, 101B and the surface of the slope part 5c is an obtuse angle.
[Hole transport layer 6A]
The hole transport layer 6A is disposed for the purpose of increasing transport efficiency when transporting holes to the organic light emitting layer 6B side, and is configured using, for example, an amine-based polymer material.
[Organic light emitting layer 6B]
The organic light emitting layer 6B is disposed for the purpose of recombining the holes supplied from the anode 2 side and the electrons supplied from the cathode 8 side during driving to emit light. The organic light emitting layer 6B of each element of the organic EL elements 100R, 100G, and 100B is configured using red, green, and blue light emitting materials in the same order.
[Electron transport layer 7]
The electron transport layer 7 is disposed for the purpose of increasing transport efficiency when electrons are transported to the organic light emitting layer 6B side, and is composed of, for example, a film made of an alkali metal or an alkaline earth metal.

[Cathode 8]
The cathode 8 is an electrode that supplies electrons to the organic light emitting layer 6B side, and is configured using a material having visible light reflection characteristics, such as aluminum or an aluminum alloy material.
[Sealing layer 9]
The sealing layer 9 is disposed for the purpose of suppressing the organic light emitting layer 6B from being deteriorated by contact with moisture, air, or the like, and is configured using a material such as SiN (silicon nitride) or SiON (silicon oxynitride). Is done.
(effect)
In the organic EL elements 100R, 100G, and 100B having the above configuration, the liquid-repellent component on the surface of the slope portion 5c of the bank 5 is appropriately decomposed and removed by the surface treatment step using the reflective film 3 at the time of manufacture. . As a result, the functional material makes good contact with the inclined surface portion 5c at the time of manufacturing, and the generation of unformed regions is suppressed, and the hole transport layer 6A and the organic light emitting layer 6B are formed inside each of the openings 101R, 101G, 101B. ing.

In this way, by suppressing the generation of the unformed regions of the hole transport layer 6A and the organic light emitting layer 6B, it is possible to prevent the occurrence of a short circuit due to the unformed regions of the hole transport layer 6A and the organic light emitting layer 6B during driving. The organic EL elements 100R, 100G, and 100B having the emission characteristics are realized.
Moreover, since the irradiation time of the energy rays in the surface treatment step can be suppressed relatively short due to the arrangement of the reflective film 3, damage to the substrate side can be reduced by irradiating the energy rays, and the organic EL elements 100R, 100G, While extending the life of 100B, the organic EL elements 100R, 100G, and 100B can be continuously driven in a high-temperature environment.
<Method for Producing Organic EL Elements 100R, 100G, 100B>
Next, the manufacturing method of organic EL element 100R, 100G, 100B is illustrated using FIGS. 3-5 is sectional drawing which shows the manufacturing process of an organic EL element sequentially. Among these, FIG. 4 is a figure which shows a surface treatment step.
[From substrate preparation step to bank formation step]
First, the substrate 1 is prepared. A film is formed on the substrate 1 through a pattern mask using a transparent conductive material based on a vacuum deposition method. Thereby, the anodes 2 are formed on the substrate 1 at predetermined intervals (FIG. 3A).

  Next, an aluminum material is deposited on the surface of each anode 2 through a pattern mask in accordance with the position of the slope portion 5c of the bank 5 to be formed later. Thereby, the reflective film 3 is formed (FIG. 3B). The position where the reflective film 3 is formed may be provided directly on the substrate 1 or may be provided beside the anode 2, and the arrangement position is not limited. Here, an example in which the reflective film 3 is provided on the anode 2 is shown.

Next, a hole injection layer 4 is formed over the entire surface of the substrate 1 on which the reflective film 3 is formed, based on a vacuum deposition method (FIG. 3C).
Next, a photosensitive resist layer is uniformly formed on the surface of the substrate 1. Based on the photolithography method, exposure is performed through a pattern mask and development processing is performed, thereby forming a bank 5 having a predetermined shape (FIG. 3D). At this time, as shown in the figure, the bank 5 is formed so that the reflective film 3 is positioned between the upper end portion 5a and the lower end portion 5b of the slope portion 5c of the bank 5.
[Surface treatment step]
Next, energy rays are uniformly irradiated from above the substrate 1 on which the bank 5 is formed. Thereby, the bank residue remaining on the surface of the substrate 1 is decomposed and removed, and the liquid repellent component on the surface of the slope portion 5c of the bank is decomposed and removed.

As an energy ray irradiated here, UV light with a wavelength of 254 nm can be used as an example.
As shown in FIG. 4, the surface of the substrate 1 is uniformly irradiated with UV light in the presence of ozone (O ₃ ). As a result, active oxygen is generated due to ozone molecules irradiated with UV light, and minute bank residues existing on the surface of the substrate 1 are decomposed and removed.

Here, since the substrate 1, the hole injection layer 4, and the bank 5 are transparent, most of the incident light of the UV light incident thereon is transmitted from the back side of the substrate 1.
However, in the region where the reflective film 3 is provided, incident light is reflected on the surface of the reflective film 3 and is irradiated upward as reflected light. Thereby, both the incident light of UV light and reflected light are irradiated to the slope part 5c of the bank 5 located above the reflective film 3, and the liquid repellency of the surface of the slope part 5c by abundant energy of UV light. The components are efficiently decomposed and removed.

The energy of the UV light incident on the bank 5 from the thickness (Z) direction is attenuated as it travels into the bank 5.
Here, the decomposition effect of the liquid repellent component on the slope portion 5c of each bank at heights h1 and h2 (h1> h2) lower than the height h0 of the bank 5 will be considered. The total amount of UV light incident on the inside of the bank 5 from the height h1 and the reflected light reflected by the reflective film 3 is the incident light of the UV light incident on the inside of the bank 5 from the height h2. And less than the total amount of reflected light. Therefore, the higher the Z-direction height of the bank is, the lower the effect of decomposing and removing the liquid-repellent component on the surface of the slope portion 5c according to the height in the Z-direction. It is considered that the decomposition and removal effect is high from the upper end 5a to the lower end 5b.

As a result, in the region of the slope portion 5c near the lower end portion 5b, which is easily in contact with the functional material, a high liquid repellent component decomposition and removal effect is exhibited. On the other hand, the liquid repellency is maintained to some extent in the region of the inclined surface portion 5c from the upper end portion 5a, and the effect of appropriately preventing the color mixture of the ink containing the functional material between the adjacent opening portions 101R is exhibited.
As described above, in the surface treatment step according to the first embodiment, even when UV irradiation is uniformly performed from above the substrate 1, the reflective film 3 is disposed, so that the water repellent component is disposed at a position corresponding to the disposed position. The effect of decomposing and removing the water repellent component can be changed according to the height of the bank 5.

Such various effects cannot be obtained simply by irradiating the energy beam from above the substrate 1, but the reflective film 3 and the bank 5 are formed at predetermined positions on the substrate 1, and the energy beam is irradiated from above. Can be obtained for the first time.
[From functional layer formation step to sealing layer formation step]
Next, ink 6AX containing a hole transport material is applied to the inside of each of the openings 101R, 101G, and 101B partitioned by the bank 5 (FIG. 5A). At this time, since the liquid repellent component is appropriately decomposed and removed on the surface of the slope portion 5c of the bank by the surface treatment step performed earlier, the bank has a good wettability. Therefore, the ink 6AX contacts the inclined surface portion 5c with a relatively small contact angle, and the ink 6AX is appropriately filled by preventing the generation of an unformed region. Thereby, the hole transport material also makes good contact with the slope portion 5c. When the filled ink 6AX is solvent-dried, a hole transport layer 6A is formed.

  Next, ink 6BX containing an organic light emitting material is applied to the inside of each of the openings 101R, 101G, and 101B (FIG. 5B). Even in this process, the liquid repellent component is appropriately decomposed and removed in the slope portion 5c of the bank in the surface treatment step, so that good wettability is exhibited, and the ink 6BX properly contacts the slope portion 5c. Thereby, the organic light emitting material is also in good contact with the inclined surface portion 5c, and generation of an unformed region of the organic light emitting layer 6B can be suppressed. The organic light emitting layer 6B is formed by drying the ink 6BX with a solvent.

Thereafter, the electron transport layer 7 is uniformly formed on the upper surface of the organic light emitting layer 6B and the surface from which the bank 5 is exposed based on the vacuum deposition method (FIG. 5C). When the cathode 8 and the sealing layer 9 are sequentially formed in the same manner, the organic EL elements 100R, 100G, and 100B are obtained (FIG. 1).
The organic EL display panel 10 is completed by forming a plurality of organic EL elements 100 on the substrate 1 in such a process.
<About each constituent material of the organic EL element 100>
When the organic EL element 100 is manufactured by the above manufacturing method, the following materials can be used as material examples of each component.
[Material of substrate 1]
Examples of the material of the substrate body in the substrate 1 include alkali-free glass, soda glass, non-fluorescent glass, phosphoric acid glass, boric acid glass, quartz, acrylic resin, styrene resin, polycarbonate resin, epoxy resin, and polyethylene. Transparent insulating materials such as polyester, silicone resin, or alumina. An organic resin film can also be used. On the other hand, a known transparent conductive material and semiconductor material can be used as the material of the TFT wiring portion in the substrate 1.
[Material of anode 2]
As the material of the anode 2, a material having visible light transparency, for example, a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) can be used.
[Material of Reflective Film 3]
The material of the reflective film 3 is not limited as long as the material has a reflection characteristic with respect to the energy rays used in the surface treatment step. For example, the use of a metal material such as aluminum or an aluminum alloy is advantageous in terms of cost.
[Material of hole injection layer 4]
As the material of the hole injection layer 4, a metal oxide material can be used for wires such as tungsten oxide and molybdenum oxide. However, it should be noted that a transparent material is used when manufacturing an organic EL element having a bottom emission structure.
[Material of bank 5]
Examples of the material of the bank 5 include a transparent organic material such as an insulating resin. Examples of the organic material include an acrylic resin, a polyimide resin, and a novolac type phenol resin. The bank 5 preferably has organic solvent resistance. Furthermore, since the bank 5 is subjected to an etching process, a baking process, and the like, it is preferable to form the bank 5 from a highly resistant material that does not cause excessive deformation or alteration to these processes.
[Material of hole transport layer 6A]
As the material of the hole transport layer 6A, either a high molecular material or a low molecular material may be used. Examples thereof include a copolymer containing a fluorene moiety and a triarylamine moiety, and an amine-based material such as a low molecular weight triarylamine derivative.
[Material of organic light emitting layer 6B]
Examples of the organic light emitting layer 6B include polymer materials such as polyfluorene, polyphenylene vinylene, polyacetylene, polyphenylene, polyparaphenylene ethylene, poly-3-hexylthiophene and derivatives thereof, and oxinoid compounds described in JP-A-5-163488. Perylene compound, coumarin compound, azacoumarin compound, oxazole compound, oxadiazole compound, perinone compound, pyrrolopyrrole compound, naphthalene compound, anthracene 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, still Compound, diphenylquinone compound, styryl compound, butadiene compound, dicyanomethylenepyran compound, dicyanomethylenethiopyran compound, fluorescein compound, pyrylium compound, thiapyrylium compound, serenapyrylium compound, telluropyrylium compound, aromatic aldadiene compound, oligophenylene compound, Fluorescent substances such as thioxanthene compounds, cyanine compounds, acridine compounds, metal complexes of 8-hydroxyquinoline compounds, metal complexes of 2-bipyridine compounds, complexes of Schiff salts and Group III metals, oxine metal complexes, rare earth complexes Can do.
[Material of electron transport layer 7]
Examples of the material for the electron transport layer 7 include alkali metal materials such as barium and alkaline earth metal materials.
[Material of cathode 8]
Examples of the cathode 8 include a conductive material having visible light reflection characteristics, such as aluminum and an aluminum alloy (ACL, etc.).
[Material of Sealing Layer 9]
Examples of the material of the sealing layer 9 include silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), silicon carbide (SiC), carbon-containing silicon oxide (SiOC), aluminum nitride (AlN), and oxide. There are materials such as aluminum (Al ₂ O ₃ ).
<Performance confirmation test>
(Changes in ink contact angle)
In order to confirm the effect of the reflective film of the above embodiment, each sample of the example and the comparative example was created and experimented.

As an experimental sample, the example has a configuration in which only the reflective film 3 and the bank 5 are formed on the substrate 1 by the same method as the manufacturing method described above. On the other hand, the comparative example has the same configuration as the example except that the reflective film 3 is not provided.
For these examples and comparative examples, an ink containing a hole transport material (hereinafter simply referred to as “ink”) is brought into contact with the bank 5 as an ink containing a functional material before the surface treatment step, and a contact angle is set. It was measured. Thereafter, in the surface treatment step, UV light having a wavelength of 254 nm was irradiated for 180 seconds, and then baked at 200 ° C. for 15 minutes. Thereafter, the ink was brought into contact with the bank 5 in the same procedure as described above, and the contact angle was measured. FIG. 6 is a graph showing changes in the contact angle between the ink and the bank 5 in Examples and Comparative Examples.

As shown in the figure, in the state before UV irradiation, the contact angle of the ink shows a relatively high value in both the example and the comparative example. However, after performing UV irradiation and baking treatment, it can confirm that the Example is reduced to the contact angle lower than a comparative example. As a result, it is confirmed that when the surface treatment step is performed with the reflective film disposed, the decomposition effect of the liquid-repellent component on the bank surface is improved at a position corresponding to the reflective film compared to the case without the reflective film. did.
(Regarding the occurrence of functional layer unformed regions)
Next, a plurality of organic EL elements of the example sample and the comparative example sample are prepared, and when the ink containing the functional material is applied to the opening portion with and without the reflective film, the functional layer is not formed. It was investigated whether there was a difference in the frequency of occurrence of the formation region.

First, 18 assembly intermediates of organic EL elements, which are comparative sample samples having the same overall structure as that of the first embodiment and not provided with only a reflective film, were prepared (Nos. 1 to 18).
Of these, No. Each of the comparative example samples 1 to 9 was subjected to initial heat treatment at about 200 ° C. for 15 minutes, and then subjected to UV irradiation for 180 seconds as a surface treatment step. Then, no. In the order of 1 to 9, ink containing a certain amount of functional material in the opening (in this experiment, ink containing a hole transport layer material) was dropped.

On the other hand, no. Each comparative sample of 10 to 18 was subjected to an initial heat treatment at about 200 ° C. for 15 minutes, and then subjected to UV irradiation for 300 seconds as a surface treatment step. Then, no. A certain amount of ink was dropped into the opening in the order of 10-18.
Next, 18 organic EL element assembly intermediates of Example samples having the same overall structure as Embodiment 1 were prepared (No. 19 to 36). Thereafter, Example No. 19 to 27 were compared with Comparative Example No. 1 to 9 were processed in the same procedure. On the other hand, Example No. In 28 to 36, initial heat treatment was not performed, and UV irradiation was performed for 180 seconds as a surface treatment step.

The results of Comparative Examples and Examples confirmed with a microscope from above each substrate are shown in FIGS. In the drawing, “determination” indicates “OK” when the unformed region could not be visually confirmed, and “NG” when it was confirmed.
As shown in FIG. 7, in the comparative example without a reflective film, in a sample with a short UV irradiation time, an unformed region of the functional layer (hole transport layer) is generated at the end in the longitudinal direction (sample No. 1, 3, 6-9). This is because UV light is transmitted through the substrate because there is no reflective film, so that the effect of decomposing the liquid repellent component on the slope of the bank cannot be obtained sufficiently, and the ink is separated from the slope of the bank. It is believed that there is. On the other hand, sample No. Regarding 10 to 18, generation of an unformed region of the functional layer could not be confirmed, but since the UV irradiation time was relatively long, it was confirmed that the substrate was damaged by thermal damage.

On the other hand, looking at each example sample in FIG. 8, it was not possible to confirm the occurrence of an unformed region even when the UV irradiation time was as short as 180 sec, regardless of the presence or absence of initial heating. This is considered to be a result of the ink being satisfactorily applied by disassembling and removing the liquid-repellent components on the bank surface with UV light even with a short irradiation time by adopting the reflective film.
From the results of this example, it is considered that the liquid-repellent component on the bank surface can be sufficiently removed by using the reflective film without heating the substrate before the UV irradiation treatment. By shortening the UV irradiation time in a short time, an effect of reducing damage to the substrate due to UV irradiation can be expected.
(Ink wet detection method)
For example, as shown in FIG. 9, a method for detecting ink wetness can be performed by looking at the element cross-sectional structure. In the example of FIG. 9, the surface shape of the bank and the substrate between the banks is represented as “underlying surface shape”, and the surface shape of the functional layer (in this case, the hole transport layer (IL layer)) is largely separated from the undersurface. If such a portion exists, it can be confirmed that an unformed region of the functional layer is generated at that portion. In this figure, the IL layer surface shape bulges in the vicinity of the right side surface, and it can be confirmed that an unformed region of the functional layer exists.
(About each film thickness of top emission type and bottom emission type IL layer)
In the manufacturing process of each element of the top emission type and the bottom emission type, the inventors of the present application drop an ink containing a functional material having the same number of droplets into the opening to form a functional layer. It was confirmed that the thickness of the functional layer could vary depending on the degree of liquid repellency. This will be described with reference to FIG.

  FIG. 10 shows the relationship between the number of ink droplets containing the hole transport layer material dropped into the opening and the film thickness of the hole transport layer (IL layer) formed accordingly. As a result of studies by the inventors of the present application, even when ink having the same number of droplets is dropped into the opening, the conventional bottom emission type element can be thicker than the top emission type element. I understood. The following can be considered as the cause of this.

  That is, in the top emission type element, since the anode is formed as a reflective anode that reflects visible light, when the UV light is irradiated in the surface treatment step, the UV light is reflected by the reflective anode. As a result, a slight amount of UV reflected light is also applied to the slope of the bank, and the liquid repellency of the slope of the bank is removed accordingly. As a result, a relatively large amount of ink applied to the opening is deposited on the slope of the bank, and the amount of adhesion to the bottom surface of the substrate surrounded by the bank is reduced accordingly, so that the thickness of the IL layer is reduced. . On the other hand, in the conventional bottom emission type element, a lot of UV light passes through the substrate as transmitted light, so that the liquid repellent component on the slope portion of the bank cannot be sufficiently decomposed and removed. Therefore, in the conventional bottom emission type element, the liquid repellency remaining on the slope portion of the bank causes a relatively small amount of ink to be deposited on the slope portion of the bank, and the thickness of the IL layer seems to be thick. However, the conventional bottom emission type has another problem that an unformed region of the IL layer occurs as described above.

Therefore, as in the first embodiment, if the reflective film is provided also in the bottom emission type element, the generation of the area where the functional layer is not formed can be effectively prevented while maintaining the thickness of the functional layer to some extent. For this reason, the manufacturing method of Embodiment 1 can be expected to achieve both the constant securing of the thickness of the functional layer and the prevention of the unformed region of the functional layer.
Next, another embodiment of the present invention will be described focusing on differences from the first embodiment.
<Embodiment 2>
FIG. 11 shows a configuration around the organic EL element 100G1 of the organic EL display panel 10A according to the second embodiment.

The organic EL element 100G1 is a top emission type, and a reflective anode 2A having visible light antireflection characteristics is formed on the surface of the substrate 1. The reflective anode 2A is made of aluminum alloy such as aluminum or ACL, for example. An electrode coating layer made of a transparent conductive material may be provided on the surface of the reflective anode 2A.
On the other hand, the cathode 8 is made of a transparent conductive material having visible light transparency, for example, ITO or IZO.

The reflective film 3A has the same configuration as the reflective film 3, but is formed in accordance with the position of the inclined surface portion 5c of the bank 5 so as to surround the reflective anode 2A. At the time of driving, light emitted from the organic light emitting layer 6B is reflected from the reflective anode 2A and taken out from the upper surface.
Also in the organic EL element 100G1 having the above configuration, the incident light of the UV light to the inclined surface portion 5c of the bank 5 and the reflection film 3A are reflected in the surface treatment step at the time of manufacture as in the first embodiment. The liquid repellent component on the surface of the slope portion 5c of the bank 5 is effectively removed by the reflected light. Thereby, generation | occurrence | production of a non-formation area | region can be prevented and the hole transport layer 6A and the organic light emitting layer 6B can be formed favorably, and the effect similar to Embodiment 1 can be anticipated.
<Embodiment 3>
FIG. 12 shows a partial front view of an organic EL display panel 10B according to the third embodiment.

In the organic EL display panel 10B, in the organic EL elements 100R2, 100G2, and 100B2 provided on the substrate 1, the reflective film 3B is partially partially only at both ends in the major axis (Y) direction of the openings 101R, 101G, and 101B. 3C.
According to such a configuration, it is possible to provide a reflective film only in the portions of the openings 101R, 101G, and 101B where the hole transport layer 6A and the organic light emitting layer 6B are not easily formed in the conventional structure. The same effects as in the first and second embodiments can be expected.

In addition, since the reflective films 3B and 3C can be formed in a smaller area than the reflective films 3 and 3A, the material can be reduced and the element structure can be simplified.
<Other matters>
In each of the above embodiments, an example in which the hole transport layer 6A is provided as one of the functional layers has been described, but this is not essential and may be omitted as appropriate.

The shape of the bank is not limited to the pixel bank structure, and may be a so-called line bank shape formed in a stripe shape in the Y direction.
The functional layer may be a hole transport layer, an organic light emitting layer, a buffer layer, or the like.
In the above embodiment, the hole transport layer and the organic light emitting layer are formed by the wet process. However, the functional layer is not limited to the wet process and may be formed by a dry process. For example, the hole transport layer and the organic light emitting layer can be formed by a vacuum process such as a vapor deposition method.

  In the surface treatment step, examples of energy rays applied to the substrate 1 include soft X-rays in addition to ultraviolet rays.

  The present invention can be used, for example, as a method for manufacturing an organic EL device used for a display device for a mobile phone, a display device such as a television, and various light sources. In any application, it is possible to expect the manufacture of an organic EL element or an organic EL display panel that can exhibit good light emission characteristics or image display performance.

1 TFT substrate 2 First electrode (transparent anode)
2A 1st electrode (reflective anode)
3, 3A, 3B, 3C Reflective film 3a, 3b End of reflective film 4 Hole injection layer 5 Bank (partition wall)
5a Bank upper end 5b Bank lower end 5c Bank slope 6A Functional layer (hole transport layer)
6B Functional layer (organic light emitting layer)
7 Electron transport layer 8 Second electrode (cathode)
9 Sealing layer 10, 10A, 10B Organic EL display panel 100R, 100G, 100B, 100R1, 100G1, 100B1, 100R2, 100G2, 100B2 Organic EL element 101R, 101G, 101B Opening

Claims (18)

A first electrode forming step of forming a first electrode using a transparent conductive material above a transparent substrate;
A reflective film forming step of forming a reflective film having a reflection characteristic with respect to energy rays on a part of the upper surface of the first electrode ;
While the presence of openings in which the inner periphery is surrounded by the oblique surface, a partition wall and containing liquid repellent component having a transparent to the energy beam, the inclined surface portion in plan view of the surface of the substrate A partition wall forming step for forming the reflective film in a substantial part, and
The energy beam is irradiated from above the substrate, and the incident light of the energy beam to the partition wall and the reflected light of the energy beam that is transmitted through the partition wall and reflected by the reflective film, A surface treatment step for reducing the liquid repellency of the partition wall surface in at least a part of the slope portion;
A functional layer forming step of forming a functional layer above the substrate by disposing a functional material inside the opening so as to be in contact with the partition wall surface having reduced liquid repellency;
A method of manufacturing an organic EL element, which includes a second electrode forming step of forming a second electrode using a conductive material having visible light reflection characteristics above the functional layer. A first electrode forming step of forming a first electrode using a conductive material having a visible light reflection property above the substrate;
A reflective film forming step of forming a reflective film having a reflection characteristic with respect to energy rays in at least a partial region around the first electrode on the substrate ;
While the presence of openings in which the inner periphery is surrounded by the oblique surface, a partition wall and containing liquid repellent component having a transparent to the energy beam, the inclined surface portion in plan view of the surface of the substrate A partition wall forming step for forming the reflective film in a substantial part, and
The energy beam is irradiated from above the substrate, and the incident light of the energy beam to the partition wall and the reflected light of the energy beam that is transmitted through the partition wall and reflected by the reflective film, A surface treatment step for reducing the liquid repellency of the partition wall surface in at least a part of the slope portion;
A functional layer forming step of forming a functional layer above the substrate by disposing a functional material inside the opening so as to be in contact with the partition wall surface having reduced liquid repellency;
A method for producing an organic EL element, comprising: a second electrode forming step of forming a second electrode using a transparent conductive material above the functional layer. The method for manufacturing an organic EL element according to claim 1, wherein in the surface treatment step, ultraviolet rays are used as the energy rays. The method for manufacturing an organic EL element according to claim 3 , wherein the reflective film formed in the reflective film forming step has a reflectance with respect to ultraviolet rays of 50% or more and 90% or less. Wherein the reflective film forming step, aluminum, manufacturing method of an aluminum alloy, rhodium, organic EL element according to any one of claims 1 to 4 forming the reflective film using at least one of rhodium alloy. In the functional layer forming step,
The method for manufacturing an organic EL device according to any one of claims 1 to 5, the ink containing the functional material is applied to the inside of the opening. The functional material is an organic light emitting material, the manufacturing method of the organic EL element according to any one of claims 1 to 6, wherein said functional layer is an organic emission layer. The functional material is a hole transport layer material, manufacturing method of the organic EL device according the functional layer to any one of claims 1 to 6, which is a hole-transporting layer. And the surface of the slope portion in the peripheral edge of the opening, a manufacturing method of an organic EL device according to any one of claims 1-8 angle is obtuse between the substrate surface in the opening. When the substrate surface is viewed in plan, the opening has a shape in which a first direction is a major axis and a second direction intersecting the first direction is a minor axis,
The reflection in the film formation process, according to any one of claims 1 to 9 forming the reflective film so as to be located on at least one of the inclined surface portion corresponding portions of the opening ends along said first direction The manufacturing method of organic EL element. A transparent substrate,
A first electrode made of a transparent conductive material provided above the substrate;
A reflective film that is provided on a part of the upper surface of the first electrode and has a reflection characteristic with respect to energy rays;
When viewed in plan the substrate surface, so that the reflective layer is positioned at an oblique surface corresponding parts, while the presence of openings in which the inner periphery is surrounded by the inclined surface, have a transparent to the energy beam And partition walls formed so as to contain a liquid repellent component;
Above the substrate, a functional layer formed inside the opening;
A second electrode made of a conductive material having a visible light reflection characteristic, formed above the functional layer;
The liquid repellency on the first partition wall surface of at least a partial region of the peripheral edge of the opening is lower than the liquid repellency of the second partition surface other than the first partition surface,
The functional layer is formed in contact with the surface of the first partition wall,
Organic EL element. A substrate,
A first electrode made of a conductive material having a visible light reflection property provided above the substrate;
A reflective film having reflection characteristics with respect to energy rays, provided in at least a partial region around the first electrode on the substrate ;
When viewed in plan the substrate surface, so that the reflective layer is positioned at an oblique surface corresponding parts, while the presence of openings in which the inner periphery is surrounded by the inclined surface, have a transparent to the energy beam And partition walls formed so as to contain a liquid repellent component;
Above the substrate, a functional layer formed inside the opening;
A second electrode made of a transparent conductive material, formed above the functional layer,
The liquid repellency on the first partition wall surface of at least a partial region of the peripheral edge of the opening is lower than the liquid repellency of the second partition surface other than the first partition surface,
The functional layer is formed in contact with the surface of the first partition wall,
Organic EL element. The reflective layer, the organic EL device according to any one of claims 1 to 12 in which the reflectance is from the material 90% to 50% of ultraviolet rays. The reflective film is aluminum, aluminum alloy, rhodium, organic EL device according to any one of claims 11 to 13 comprising using at least one of rhodium alloy. The organic EL device according to any one of claims 11 to 14 , wherein the functional material is an organic light emitting material, and the functional layer is an organic light emitting layer. The functional material is a hole transport layer material, the functional layer is an organic EL element according to any one of claims 11 to 14, which is a hole-transporting layer. The organic EL element according to any one of claims 11 to 16 , wherein an angle between the surface of the slope portion at the periphery of the opening and the surface of the substrate in the opening is an obtuse angle. An organic EL display panel comprising a plurality of organic EL elements according to any one of claims 11 to 17 arranged in a planar manner along a first direction and a second direction intersecting each other.