WO2011105455A1

WO2011105455A1 - Relief printing plate, printing device using same, thin film manufacturing method, and organic el element manufacturing method

Info

Publication number: WO2011105455A1
Application number: PCT/JP2011/054040
Authority: WO
Inventors: 行一六原
Original assignee: 住友化学株式会社
Priority date: 2010-02-25
Filing date: 2011-02-23
Publication date: 2011-09-01
Also published as: JP2011175909A; TW201146078A

Abstract

A relief printing plate is used in a relief printing method using a transfer roller having a smooth surface and has a protruding portion on the surface of which a predetermined recess is formed. The protruding portion has the plurality of recesses arranged so as to be symmetrical with respect to a point. The relief printing plate has a plurality of protruding portions extending in a predetermined direction at predetermined intervals. The protruding portions have the recesses extending in a predetermined direction or the recesses extending in a direction vertical to the predetermined direction.

Description

Letterpress printing plate, printing apparatus using the same, thin film manufacturing method, and organic EL element manufacturing method

The present invention relates to a relief printing plate, a method for producing a thin film using the relief printing plate, a printing apparatus, and a method for producing an organic EL (Electro-Luminescence) element using the relief printing plate.

In letterpress printing, printing is usually performed as follows. First, ink is supplied to the entire surface of the cylindrical transfer roll, and then the relief printing plate is pressed against the transfer roll to transfer the ink to the convex portions of the relief printing plate. Further, printing is performed by pressing the relief printing plate against the printing material, and a thin film is formed on the printing material with a predetermined pattern.

A so-called anilox roll is frequently used for the transfer roll described above. The anilox roll is a transfer roll having fine irregularities formed on the surface, and the amount of ink transferred to the relief printing plate can be adjusted by adjusting the shape of the irregularities formed on the surface. A relief printing method using an anilox roll will be described with reference to FIG.

FIG. 4 is a diagram schematically showing a relief printing method using an anilox roll. Printing ink (ink supply source) 22 is accommodated in an ink tank TK. The anilox roll 23 ′ is rotatably supported in a state where a part of the anilox roll 23 ′ is immersed in the ink 22, and rotates counterclockwise as indicated by an arrow in FIG. 4. Ink adheres to the surface of the anilox roll 23 ′ that has passed through the ink 22. The ink adheres in a larger amount than the amount to be transferred to the relief printing plate 12 ', but the excess ink is removed by a doctor blade DB before being transferred to the relief printing plate 12'. As shown in FIG. 4, the doctor blade DB is pressed against the anilox roll 23 'before the relief printing plate 12' wound around the plate cylinder 24 is pressed against the anilox roll 23 '. This removes excess ink and fills the recesses on the surface of the anilox roll 23 'with the intended amount of ink. When the relief printing plate 12 ′ is pressed in a state where the intended amount of ink is held on the anilox roll 23 ′, the intended amount of ink is transferred to the relief printing plate, and this is further printed on the printing medium. Is done.

By using an anilox roll in this way, it is possible to print an intended amount of ink on a printing medium, and as a result, a thin film with an intended thickness can be formed on the printing medium (for example, Patent Documents). 1).

JP 2006-252787 A

As described above, the ink supplied to the anilox roll is transferred to the relief printing plate, but not all of it is transferred, and a part of the ink remains on the anilox roll without being transferred. The ink remaining on the anilox roll moves toward the ink tank as the anilox roll rotates, and is again stored in the ink tank. Since the ink supplied to the anilox roll partially evaporates during the rotation of the anilox roll, the solid content concentration increases. Therefore, ink with a high solid content concentration continues to be stored in the ink tank, and as a result, the ink composition in the ink tank changes with time. Since the ink composition in the ink tank changes as described above, there is a problem that it is difficult to continuously form a thin film having a certain property by the relief printing method using an anilox roll. Although it may be possible to wash the anilox roll to prevent the ink from returning to the ink tank, it is difficult to completely remove the ink filled in the recesses on the surface of the anilox roll. It is difficult to completely prevent the ink from returning to the ink tank.

Therefore, the present inventors examined forming a thin film by using a transfer roll having a flat surface instead of an anilox roll having irregularities formed on the surface. In a transfer roll having a flat surface, an intended amount of ink does not adhere to the surface of the transfer roll simply by immersing the transfer roll in the ink. Therefore, the ink is usually supplied to the surface of the transfer roll by a slit coating method or the like. The amount of ink transferred from the transfer roll to the relief printing plate can be adjusted to some extent by controlling the amount of ink supplied to the transfer roll, but in reality, only the ink supply amount is adjusted. In this case, the intended amount of ink was not transferred to the relief printing plate, and as a result, a new problem that a thin film having the intended thickness could not be formed was confirmed.

Accordingly, an object of the present invention is to provide a relief printing plate capable of forming a thin film having a desired film thickness by a relief printing method using a transfer roll having a flat surface, a printing apparatus using the relief printing plate, a method for producing a thin film, And the manufacturing method of an organic EL element is to provide.

The relief printing plate of the present invention is a relief printing plate used in a relief printing method using a transfer roll having a flat surface, and has a convex portion having a predetermined depression formed on the surface.

Further, in the relief printing plate of the present invention, it is preferable that the projection has a plurality of the depressions arranged so as to be point-symmetric.

Moreover, it is preferable that the relief printing plate of the present invention has a plurality of the convex portions extending in a predetermined direction at predetermined intervals.

Further, in the relief printing plate of the present invention, it is preferable that the convex portion has the depression extending in the predetermined direction or the depression extending in a direction perpendicular to the predetermined direction.

Moreover, the printing apparatus of the present invention includes the ink supply source, the transfer roll supplied with the ink from the ink supply source, the surface of the transfer roll, and the relief printing, to which the ink supplied to the surface of the transfer roll is transferred. With a version.

The method for producing a thin film of the present invention includes a step of supplying ink to a transfer roll having a flat surface, a step of pressing the relief printing plate against the transfer roll, and transferring the ink to the relief printing plate, The method includes a step of pressing a relief printing plate against a printing material to print the ink, and a step of solidifying the ink to form a thin film on the printing material.

Moreover, the manufacturing method of the organic EL element of this invention is a manufacturing method of an organic EL element provided with a pair of electrodes and the organic EL layer provided between these electrodes, Comprising: One electrode of a pair of electrodes is formed. A step of supplying an organic EL ink containing a material to be the organic EL layer to a transfer roll having a flat surface, pressing the relief printing plate against the transfer roll, and applying the organic EL ink to the relief printing A step of transferring to a plate, a step of pressing the relief printing plate against a pair of the electrodes, printing the organic EL ink, and solidifying the organic EL ink to form an organic EL layer on the one electrode And a step of forming the other of the pair of electrodes on the organic EL layer.

According to the present invention, a thin film having a desired film thickness can be formed by a relief printing method using a transfer roll having a flat surface.

FIG. 1 is a diagram schematically showing a relief printing plate of the present embodiment. FIG. 2 is a diagram schematically illustrating a convex portion in which continuous depressions are formed. FIG. 3 is a diagram schematically illustrating a printing apparatus including the above-described relief printing plate. FIG. 4 is a diagram schematically showing a relief printing method using an anilox roll. FIG. 5 is a diagram showing a state of exposure during printing plate preparation. FIG. 6 is a diagram showing a state of exposure during printing plate preparation. FIG. 7 is a longitudinal sectional view of the organic EL element. FIG. 8 is a longitudinal sectional view of the organic EL element. FIG. 9 is a longitudinal sectional view of the organic EL element. FIG. 10 is a longitudinal sectional view of the organic EL element. FIG. 11 is a longitudinal sectional view of the organic EL element. FIG. 12 is a longitudinal sectional view of the organic EL element. FIG. 13 is a longitudinal sectional view of the organic EL element. FIG. 14 is a longitudinal sectional view of the organic EL element. FIG. 15 is a longitudinal sectional view of a display device including an organic EL element.

The relief printing plate of the present invention is a relief printing plate used in a relief printing method using a transfer roll having a flat surface, and has a convex portion having a predetermined depression formed on the surface. Since the preparation is easy, the relief printing plate is preferably made of a resin.

Thus, the amount of ink transferred from the transfer roll can be adjusted by forming a predetermined depression on the surface of the convex portion. Thereby, the film thickness of the printed thin film can be adjusted.

On the relief printing plate, a convex portion of a pattern corresponding to the pattern of the thin film to be formed on the printing medium is formed. For example, when a plurality of strip-shaped thin films are formed on a printing medium, a plurality of protrusions extending in a predetermined direction with a predetermined distance from each other so as to correspond to the pattern of the strip-shaped thin film Is provided on the relief printing plate. For example, when forming a plurality of thin films arranged in a matrix, that is, forming a plurality of thin films arranged at predetermined intervals in a predetermined row direction and at predetermined intervals in a predetermined column direction. In this case, a plurality of convex portions arranged in a matrix so as to correspond to the pattern of the plurality of thin films are provided on the relief printing plate.

FIG. 1 is a diagram schematically showing a relief printing plate of this embodiment. FIG. 1A is a plan view of a relief printing plate, and FIG. 1B is a cross-sectional view thereof. In FIG. 1, a plurality of protrusions 11 extending in a predetermined direction with a predetermined interval from each other, that is, a plurality of protrusions 11 arranged in a stripe shape are formed on the flexible support film 100. The made relief printing plate 12 is shown as one embodiment. In addition, in FIG. 1 (A) and FIG. 2 mentioned later, the hollow 14 is hatched.

As shown in FIG. 1, a predetermined depression 14 is provided in the convex portion 11 of the relief printing plate 12. The shape and arrangement of the recesses 14 are appropriately set according to the amount of ink transferred. For example, in plan view, the amount of ink transferred can be adjusted by appropriately adjusting the ratio of the area of the depressions 14 to the area of the protrusions 11 and the depth of the depressions 14.

It is preferable that the convex part 11 has a plurality of the depressions 14 arranged so as to be point-symmetric. In other words, on the plane perpendicular to the thickness direction of the relief printing plate 12, the plurality of depressions 14 are preferably arranged so as to be point-symmetric. In other words, it is preferable that the depressions 14 are formed in each convex portion 11 so as to be line symmetric with respect to a predetermined symmetry axis whose axial direction coincides with the thickness direction of the relief printing plate 12. As will be described later, the relief printing plate 12 is used by being wound around a predetermined plate cylinder. The arrangement of the depressions 14 means an arrangement in a state where the relief printing plate 12 is placed on a plane. By arranging a plurality of depressions symmetrically in this way, the film thickness of the ink transferred from the transfer roll to the convex portion can be made uniform, and as a result, a thin film with a uniform film thickness is formed on the printing medium. be able to.

FIG. 1 shows a relief printing plate in which two depressions 14 are provided in the width direction perpendicular to the direction in which each protrusion extends, but the number of depressions in the width direction is not limited to two. It may be one, or three or more. In FIG. 1, the circular depression 14 is shown in plan view, but the shape of the depression 14 in plan view is not limited to a circle, and may be polygonal or substantially elliptical. The width direction is also a direction perpendicular to the thickness direction of the substrate.

Moreover, although the convex part in which the hollow was provided discretely was shown in FIG. 1, the hollow may be formed continuously. FIG. 2 is a diagram schematically showing a convex portion in which continuous depressions are formed. In FIG. 2, one convex part of the convex part formed in multiple numbers is expanded and shown typically. Even if the depressions are continuously formed, the depressions are preferably arranged so as to be point-symmetric.

For example, in the case of a relief printing plate having a plurality of projections extending in a prescribed direction at a predetermined interval from each other, that is, in the case of a relief printing plate having stripe-like projections, the projection 11 is: It is preferable to have a plurality of the recesses extending in the predetermined direction or a plurality of the recesses extending in a direction perpendicular to the predetermined direction. That is, the convex portion is a recess 14 extending in the same direction as the direction in which the convex portion extends as shown in FIG. 2 (A), or the direction in which the convex portion extends as shown in FIG. 2 (B). It is preferable to have a recess 14 extending in the vertical direction. Note that FIG. 2A shows a convex portion in which three dents extending in the same direction as the direction in which the convex portion extends are shown, but the number of dents is not limited to three, but one or more. If it is.

Further, as shown in FIG. 2C, a lattice-like depression 14 may be formed in the convex portion 11, and as shown in FIG. 2D, the convex portion 11 has a V-shape in plan view. A dent 14 may be formed.

Next, a method for producing a relief printing plate 12 including the projections 11 with depressions will be described. The relief printing plate 12 of this embodiment can be produced using, for example, a photosensitive resin. For example, as shown in FIG. 5A, first, a negative photosensitive resin (photoresist) 11 ′ is formed on a predetermined substrate 100. The negative photosensitive resin 11 ′ has a property that when exposed to light, the solubility in the developer is lowered, and the exposed portion remains after development. Next, the photosensitive resin 11 ′ is exposed with UV light through the photomask M, and the portion constituting the convex portion 11 is cured. At the time of exposure, the region excluding the region (b) where the depressions 14 are formed from the region (a) where the convex portions 11 are formed (see FIG. 5B) <region (a) −region (b )> And the region (b), the exposure amount is varied. FIG. 5B shows a case where only the region (b) corresponding to the depression 14 is exposed. When different exposure amounts are used, specifically, the exposure amount of the region <region (a) −region (b)> is made larger than that of the region (b). In order to vary the exposure amount, the exposure may be performed in two steps. For example, as shown in FIG. 6, in the first time, the region (ab) = {region (a) −region (b)} is exposed in the projected portion formation region, and the second time, the region (a) is exposed. What is necessary is just to expose. Since the region (b) is included in the region (a), the exposure amount of the region (b) is lower than the exposure amount of the region (a). Of course, when the exposure amount of the first region (ab) is large, only the region (b) is smaller than the exposure amount (exposure amount per unit area) of the region (ab) in the second time. You may expose by exposure amount (exposure amount per unit area). Then, the uncured photosensitive resin is washed away and developed. As described above, the region <region (a) −region (b)> is hardened more than the region (b) by varying the exposure amount. Therefore, during development, the region <b> The region <region (a) -region (b)> remains, in other words, in the region where the projection is to be formed, the region (b) is significantly dissolved from the periphery thereof, so that the depression 14 is formed. The convex part 11 formed in the top surface is obtained. In this way, the relief printing plate 12 can be obtained. The exposure may be performed only from the photosensitive resin side. However, when the substrate is transparent to the exposure light, the exposure may be performed in advance from the substrate side.

As the photosensitive resin 11 ', for example, polyamide, polyimide, acrylate, or the like can be used. For the substrate 100, polyethylene terephthalate, polyimide, polycarbonate, or the like can be used.

Next, a method for producing a thin film using the above-described relief printing plate 12 will be described. FIG. 3 is a diagram schematically illustrating a printing apparatus 21 including the relief printing plate 12 described above. The printing apparatus 21 mainly includes an ink supply source 22, a transfer roll 23 having a flat surface to which ink is supplied from the ink supply source 22, and the ink supplied to the surface of the transfer roll 23. The relief printing plate 12 is provided.

As described above, the relief printing plate 12 is usually used by being wound around the plate cylinder 24. For example, when using a relief printing plate provided with stripe-shaped projections, the relief printing plate should be such that the direction in which the projections extend matches the circumferential direction of the plate cylinder, or the direction in which the projections extend. Is wound around the plate cylinder so as to coincide with the axial direction of the plate cylinder. In the present embodiment, the plate cylinder 24 is rotatably supported around the axis CR1 and is rotated by a driving force from the rotation driving mechanism DRV1. In FIG. 3, the plate cylinder 24 rotates clockwise as indicated by an arrow, and the relief printing plate 12 also rotates as the plate cylinder 24 rotates.

The transfer roll 23 is rotatably supported so that its axis CR2 is parallel to the axis of the plate cylinder 24, and rotates by the driving force from the rotation driving mechanism DRV2. In FIG. 3, as indicated by an arrow, the transfer roll 23 rotates counterclockwise. The transfer roll 23 is made of, for example, chromium, chromium oxide, aluminum, aluminum oxide, or the like.

The ink supply source 22 stores ink and supplies it to the transfer roll 23. In this embodiment, the slit nozzle 25 is used to supply ink to the transfer roll 23.

Furthermore, in this embodiment, the printing apparatus further includes a cleaning mechanism 26. The cleaning mechanism 26 cleans the ink remaining on the transfer roll 23 after the ink is transferred from the transfer roll 23 to the relief printing plate 12. For example, the cleaning mechanism 26 includes a doctor blade, and scrapes ink remaining on the transfer roll 23 by pressing the doctor blade against the transfer roll 23. The transfer roll 23 may be washed using a predetermined rinse liquid.

The printing apparatus 21 further includes a transport table 28 that transports the printing medium 27. The transport table 28 holds the printing material 27 and moves in parallel to the tangential direction of the relief printing plate 12 at the same speed as the tangential velocity of the relief printing plate 12. The transfer table 28 normally moves horizontally. As the transport table 28 moves, the printing medium also moves in parallel.

The ink supplied from the ink supply source 22 is supplied onto the transfer roll 23 through the slit nozzle 25. Thus, the ink roll is rotated while the ink is supplied from the slit nozzle 25, whereby an ink thin film is formed on the surface of the transfer roll 23. Note that the surface of the transfer roll 23 is flat (smooth). In other words, the root mean square roughness (RMS) of the surface of the transfer roll 23 is significantly smaller than the RMS of the surface of the relief printing plate 12 having irregularities.

Since the relief printing plate 12 rotates in contact with the transfer roll 23, the ink supplied to the transfer roll 23 is sequentially transferred onto the surface of the projection of the relief printing plate 12.

In this way, the relief printing plate 12 to which the ink is transferred and holds the ink on the convex portion rotates while being pressed against the printing medium 27. Since the printing medium 27 moves in parallel with the rotation of the relief printing plate 12, the ink held on the convex portions of the relief printing plate 12 is sequentially printed on the printing medium 27.

The ink remaining on the transfer roll 23 without being transferred to the relief printing plate 12 is removed from the transfer roll 23 by the cleaning mechanism 26.

Through the above steps, the step of supplying ink to a transfer roll having a flat surface, the step of pressing the above-described relief printing plate against the transfer roll, transferring the ink to the relief printing plate, and printing the relief printing plate And a step of printing the ink on the body, and further solidifying the ink to form a thin film of ink on the substrate, thereby forming a thin film on the substrate .

The ink can be solidified by removing the solvent. The removal of the solvent is performed by, for example, natural drying, heat drying, vacuum drying, or the like. In addition, when the ink contains a material that is cured by applying light or heat, the ink may be solidified by irradiating light or applying heat after the ink is printed on the printing medium. .

As described above, an intended amount of ink can be transferred to the relief printing plate 12 by forming the predetermined depressions 14 in the projections 11. As a result, an intended amount of ink can be printed on the printing medium 27, and as a result, a thin film having an intended thickness can be formed on the printing medium.

By using the printing apparatus described above, various types of thin films can be formed on the substrate. For example, by appropriately adjusting the ink to be used, a conductive thin film functioning as an electrode or a wiring, an active layer of an organic photoelectric conversion element, a semiconductor layer of an organic thin film transistor, and an organic EL layer of an organic EL element described later can be formed. it can.

An organic EL element can be formed using the above-described relief printing method. That is, the manufacturing method of the organic EL element 1 of the present embodiment is a manufacturing method of an organic EL element including a pair of

electrodes

2 and 5 and an organic EL layer 10 provided between the electrodes as shown in FIG. A step of forming one electrode 2 of the pair of electrodes, and a step of supplying an organic EL ink containing a material to be the organic EL layer (particularly, the light emitting layer 4) 10 to a transfer roll having a flat surface. The above-described relief printing plate 12 is pressed against the transfer roll 23 to transfer the organic EL ink to the relief printing plate 12, and the relief printing plate 12 is pressed against the pair of one electrode 2 to print the organic EL ink. The step of solidifying the organic EL ink, forming the organic EL layer (particularly the light emitting layer 4) 10 on one electrode 2, and the other electrode 5 of the pair of electrodes on the organic EL layer 10 Forming an organic EL Child process for the preparation of.

The organic EL element 1 is used as a pixel of a display device, for example. In such a display device, as shown in FIG. 15, a plurality of organic EL elements 1 are arranged on a support substrate 6 in a predetermined arrangement. For example, the plurality of organic EL elements 1 are arranged in a matrix on the support substrate 6. That is, the plurality of organic EL elements 1 are arranged in a line with a predetermined interval in a predetermined row direction and with a predetermined interval in a predetermined column direction.

A partition wall IW for separating a plurality of organic EL elements is usually provided on the support substrate 6. The plurality of organic EL elements are respectively formed in regions divided by the partition walls IW.

The partition wall IW is provided in a stripe shape or a lattice shape, for example. In the case where stripe-shaped partition walls are provided, a plurality of partition walls extending in a predetermined direction are provided on the substrate at predetermined intervals. And each organic EL element 1 is provided between each partition IW, and is arrange | positioned at predetermined intervals along the direction where the partition IW extends between these partition IW. Further, when the lattice-shaped partition wall IW is provided, each organic EL element 1 is provided in a region divided by the lattice-shaped partition wall.

In the present embodiment, a method for manufacturing a plurality of organic EL elements on a substrate provided with a stripe-shaped partition wall IW will be described.

Organic EL element 1 includes a pair of

electrodes

2 and 5. The pair of electrodes includes an anode and a cathode. That is, one of the pair of electrodes functions as one of the anode and the cathode, and the other of the pair of electrodes serves as the other of the anode and the cathode. Function. First, one electrode 2 of each organic EL element is formed on the support substrate 6. That is, one electrode 2 having a number corresponding to the number of organic EL elements 1 is formed on the support substrate 6. The plurality of one electrodes 2 are arranged in a matrix in a plan view.

Next, a stripe-shaped partition wall IW is formed. A stripe-shaped partition is formed between one

adjacent electrode

2 and 2. The partition wall IW can be formed by a photolithography method using, for example, a photosensitive resin.

Next, the organic EL layer 10 is formed. In the present embodiment, an organic EL ink containing a material to be the organic EL layer 10 is supplied between the stripe-shaped partition walls IW, and further solidified to thereby form a strip-shaped organic EL layer between the stripe-shaped partition walls IW. Form. The organic EL ink is supplied between the stripe-shaped partition walls IW by the above-described relief printing method. That is, in the above-described relief printing method, an organic EL ink containing a material that becomes an organic EL layer is used as the ink. Further, as the relief printing plate 12, stripe-like projections 11 corresponding to the pattern between the partition walls IW and IW are used. The letterpress printing plate 12 on which is formed is used. By supplying the organic EL ink between the partition walls IW and IW by the above-described relief printing method and further solidifying it, the strip-shaped organic EL layer 10 can be formed between the partition walls IW and IW.

The organic EL ink used for forming the organic EL layer 10 has a solid content concentration of usually about 0.5 wt% to 3 wt% and a viscosity of usually about 5 cP to 100 cP. Since 1 cP (centipoise) = 0.001 Pa · s (Pascal second), 5 cP to 100 cP is 0.005 Pa · s to 0.1 Pa · s. The solvent or dispersion medium of the organic EL ink may be any solvent that uniformly dissolves or disperses the material that becomes the organic EL layer. For example, chlorinated solvents such as chloroform, methylene chloride, dichloroethane, ether solvents such as tetrahydrofuran, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone and methyl ethyl ketone, ethyl acetate, butyl acetate, and ethyl cellosolve An ester solvent such as acetate and water can be appropriately used as a solvent or a dispersion medium.

The film thickness of the organic EL layer 10 is usually about 30 nm to 120 nm. Since the characteristics of the organic EL element 1 greatly depend on the film thickness of the organic EL layer 10, it is desired to form an organic EL layer having an intended film thickness. In the present embodiment, an intended amount of organic EL ink can be supplied between the partition walls IW and IW by forming a predetermined depression in the convex portion 11 of the relief printing plate 12, and as a result, the intended film thickness is obtained. The organic EL layer 10 can be formed. Thereby, the organic EL element 1 having desired characteristics can be formed.

Between the pair of

electrodes

2 and 5, not only one organic EL layer but also a plurality of organic EL layers are provided as necessary. The organic EL layer means all layers provided between a pair of electrodes. At least one light emitting layer 4 is provided as an organic EL layer between the pair of electrodes (see FIG. 14). When a plurality of organic EL layers are provided, at least one organic EL layer is formed by the relief printing method of the present invention described above. Of the plurality of organic EL layers, the organic EL layer that can be formed by a coating method is preferably formed by the relief printing method of the present invention described above. In the case of a color display device, it is necessary to coat organic EL inks that emit red, green, and blue light separately between predetermined partitions IW and IW. In this case, the organic EL ink of each color can be applied separately by forming the pattern of the convex portion 11 of the printing plate so as to correspond to the pattern to which the organic EL ink of each color is supplied.

After forming the organic EL layer 10, the other electrode 5 is formed on the organic EL layer. As a result, a plurality of organic EL layers 10 are formed on the substrate 6 as shown in FIG. As a method for forming the above-described electrode, a vacuum deposition method, a sputtering method, an ion plating method, a lamination method, or a plating method can be used.

In the present embodiment, the method of forming the plurality of organic EL elements 1 on the substrate 6 on which the stripe-shaped partition walls IW are formed has been described. However, the plurality of organic EL elements are formed on the substrate on which the lattice-shaped partition walls are formed. Even if it is the method of forming, the organic EL layer of each organic EL element can be formed by the relief printing method mentioned above. In this case, a relief printing plate in which a plurality of projections arranged in a matrix form is used so as to correspond to the matrix pattern divided by the grid-like partition walls may be used.

<Configuration of organic EL element>
The organic EL element can have various layer configurations. The layer structure of the organic EL element, the configuration of each layer, and the method for forming each layer will be described in more detail below.

The organic EL element includes a pair of

electrodes

2 and 5 and one or a plurality of organic EL layers 10 provided between the

electrodes

2 and 5, and at least one layer of light emission as one or a plurality of organic EL layers. Has a layer. The organic EL element may include a layer containing an inorganic substance and an organic substance, an inorganic layer, and the like. The organic substance constituting the organic layer may be a low molecular compound or a high molecular compound, or a mixture of a low molecular compound and a high molecular compound. The organic layer preferably contains a polymer compound, and preferably contains a polymer compound having a polystyrene-equivalent number average molecular weight of 10 ³ to 10 ⁸ .

Examples of the organic EL layer provided between the cathode and the light emitting layer include an electron injection layer, an electron transport layer, and a hole blocking layer. When both the electron injection layer and the electron transport layer are provided between the cathode and the light emitting layer, the layer close to the cathode is called an electron injection layer, and the layer close to the light emitting layer is called an electron transport layer. Examples of the organic EL layer provided between the anode and the light emitting layer include a hole injection layer, a hole transport layer, and an electron block layer. When both the hole injection layer and the hole transport layer are provided, a layer close to the anode is referred to as a hole injection layer, and a layer close to the light emitting layer is referred to as a hole transport layer.

The organic EL element can include a predetermined layer in addition to the light emitting layer between the pair of electrodes as described above. Examples of the organic layer 10 formed between the electrode (anode) 2 and the electrode (cathode) 5 formed on the support substrate 6 include the following structures.

As shown in FIG. 7, the organic EL element has an organic layer Y between the electrode (anode) 2 and the light emitting layer 4 and an organic layer between the electrode (cathode) 5 and the light emitting layer 4. It can be set as the structure where the layer X interposes.

As shown in FIG. 8, the organic EL element has a structure in which an organic layer Y is interposed between the electrode (anode) 2 and the light emitting layer 4, and the electrode 5 is formed directly on the light emitting layer 4. It can be set as a structure.

As the structure of the organic EL element, as shown in FIG. 9, the organic layer X is interposed between the electrode (cathode) 5 and the light emitting layer 4, and the light emitting layer 4 is in direct contact with the electrode 2. It can be.

The organic layer X may be composed of two or more kinds of organic layers X1 and X2 as shown in FIG. 10, and the organic layer Y is composed of two or more kinds of organic layers Y1 and Y2 as shown in FIG. It may be.

As the structure of the organic EL element, only the light emitting layer 4 may be formed between the anode 2 and the cathode 5 as shown in FIG.

Examples of the layer X provided between the cathode 5 and the light emitting layer 4 include an electron injection layer, an electron transport layer, and a hole blocking layer. As shown in FIG. 10, when both the electron injection layer X1 and the electron transport layer X2 are provided between the cathode 5 and the light emitting layer 4, the layer in contact with the cathode 5 is referred to as the electron injection layer X1, The layer excluding the electron injection layer X1 is referred to as an electron transport layer X2.

The electron injection layer has a function of improving the electron injection efficiency from the cathode. The electron transport layer has a function of improving electron injection from the layer in contact with the surface on the cathode side. The hole blocking layer has a function of blocking hole transport. In the case where the electron injection layer and / or the electron transport layer have a function of blocking hole transport, these layers may also serve as the hole blocking layer.

The fact that the hole blocking layer has a function of blocking hole transport makes it possible, for example, to produce an element that allows only hole current to flow, and confirm the blocking effect by reducing the current value.

Examples of the layer Y provided between the anode 2 and the light emitting layer 4 include a hole injection layer, a hole transport layer, and an electron block layer. As shown in FIG. 11, when both the hole injection layer Y1 and the hole transport layer Y2 are provided between the anode 2 and the light emitting layer 4, the layer in contact with the anode 2 is the hole injection layer. The layer excluding the hole injection layer Y1 is referred to as Y1, and is referred to as a hole transport layer Y2.

The hole injection layer has a function of improving the hole injection efficiency from the anode. The hole transport layer has a function of improving hole injection from a layer in contact with the surface on the anode side. The electron blocking layer has a function of blocking electron transport. In the case where the hole injection layer and / or the hole transport layer has a function of blocking electron transport, these layers may also serve as an electron blocking layer.

The fact that the electron blocking layer has a function of blocking electron transport makes it possible, for example, to produce an element that allows only electron current to flow, and confirm the blocking effect by reducing the current value.

The electron injection layer and the hole injection layer are sometimes collectively referred to as a charge injection layer, and the electron transport layer and the hole transport layer are sometimes collectively referred to as a charge transport layer.
An example of a layer structure that can be taken by the organic EL element of the present embodiment is shown below.
a) Anode 2 / light emitting layer 4 / cathode 5 (see FIG. 14)
b) Anode 2 / hole injection layer Y / light emitting layer 4 / cathode 5 (see FIG. 8)
c) Anode 2 / hole injection layer Y / light emitting layer 4 / electron injection layer X / cathode 5 (see FIG. 7)
d) Anode 2 / hole injection layer Y / light emitting layer 4 / electron transport layer X / cathode 5 (see FIG. 7)
e) Anode 2 / hole injection layer Y / light emitting layer 4 / electron transport layer X2 / electron injection layer X1 / cathode 5 (see FIGS. 7 and 10)
f) Anode 2 / hole transport layer Y / light emitting layer 4 / cathode 5 (see FIG. 8)
g) Anode 2 / hole transport layer Y / light emitting layer 4 / electron injection layer X / cathode 5 (see FIG. 7)
h) Anode 2 / hole transport layer Y / light emitting layer 4 / electron transport layer X / cathode 5 (see FIG. 7)
i) Anode 2 / hole transport layer Y / light emitting layer 4 / electron transport layer X2 / electron injection layer X1 / cathode 5 (see FIGS. 7 and 10)
j) Anode 2 / hole injection layer Y1 / hole transport layer Y2 / light emitting layer 4 / cathode 5 (see FIGS. 8 and 11)
k) Anode 2 / hole injection layer Y1 / hole transport layer Y2 / light emitting layer 4 / electron injection layer X / cathode 5 (see FIGS. 7 and 11)
l) Anode 2 / hole injection layer Y1 / hole transport layer Y2 / light emitting layer 4 / electron transport layer X / cathode 5 (see FIGS. 7 and 11)
m) Anode 2 / hole injection layer Y1 / hole transport layer Y2 / light emitting layer 4 / electron transport layer X2 / electron injection layer X1 / cathode 5 (see FIGS. 7, 10 and 11)
n) Anode 2 / light emitting layer 4 / electron injection layer X / cathode 5 (see FIG. 9)
o) Anode 2 / light emitting layer 4 / electron transport layer X / cathode 5 (see FIG. 9)
p) Anode 2 / light emitting layer 4 / electron transport layer X2 / electron injection layer X1 / cathode 5 (see FIGS. 9 and 10)
(Here, the symbol “/” indicates that the layers sandwiching the symbol “/” are adjacently stacked. The same applies hereinafter.)
The organic EL element of the present embodiment may have two or more light emitting layers. In any one of the layer configurations of a) to p) above, when the laminate sandwiched between the anode and the cathode is referred to as “structural unit A”, the configuration of the organic EL device having two light emitting layers is as follows. And the layer structure shown in the following q). Note that the two (structural unit A) layer structures may be the same or different.
q) Anode 2 / (structural unit A) / charge generation layer Z / (structural unit A) / cathode 5 (see FIG. 12)
Further, when “(structural unit A) / charge generation layer Z” is “structural unit B”, examples of the configuration of the organic EL element having three or more light emitting layers include the layer configuration shown in the following r).
r) Anode 2 / (structural unit B) x / (structural unit A) / cathode 5 (see FIG. 13)
The symbol “x” represents an integer of 2 or more, and (structural unit B) x represents a stacked body in which the structural unit B is stacked in x stages. A plurality of (structural units B) may have the same or different layer structure.

Here, the charge generation layer Z is a layer that generates holes and electrons by applying an electric field. Examples of the charge generation layer Z include a thin film made of vanadium oxide, indium tin oxide (IndiumＩｎTin Oxide: abbreviated as ITO), molybdenum oxide, or the like.

Organic EL element is usually provided on a support substrate. The organic EL element may be provided on the support substrate with the anode of the pair of electrodes including the anode and the cathode disposed closer to the support substrate than the cathode, and the cathode is disposed closer to the support substrate than the anode. May be provided on the support substrate. For example, in the above-described configurations a) to r), an organic EL element having a structure in which each layer is stacked on the support substrate in order from the right side or an organic EL element having a structure in which each layer is stacked on the support substrate from the left side may be used. .

The order of the layers to be laminated, the number of layers, and the thickness of each layer can be appropriately set in consideration of light emission efficiency and element lifetime.

Next, the material and forming method of each layer constituting the organic EL element will be described more specifically.

<Anode>
In the case of an organic EL element having a configuration in which light emitted from the light emitting layer is emitted outside the element through the anode, an electrode exhibiting optical transparency is used for the anode. As the electrode exhibiting light transmittance, a thin film of metal oxide, metal sulfide, metal or the like can be used, and an electrode having high electrical conductivity and light transmittance is preferably used. Specifically, a thin film made of indium oxide, zinc oxide, tin oxide, ITO, indium zinc oxide (abbreviated as IZO), gold, platinum, silver, copper, or the like is used. Among these, ITO, IZO Or a thin film made of tin oxide is preferably used. Examples of a method for producing the anode include a vacuum deposition method, a sputtering method, an ion plating method, and a plating method. Further, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used as the anode.

The film thickness of the anode is appropriately set in consideration of the required characteristics and the simplicity of the film forming process, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

<Hole injection layer>
As the hole injection material constituting the hole injection layer, oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide, phenylamine type, starburst type amine type, phthalocyanine type, amorphous carbon, polyaniline, And polythiophene derivatives.

Examples of the method for forming the hole injection layer include film formation from a solution containing a hole injection material. For example, a hole injection layer can be formed by coating a film containing a hole injection material by a predetermined coating method and solidifying the solution.

As the coating method, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen printing method, letterpress printing method (flexographic printing method) Printing method), offset printing method, inkjet printing method and the like, and the relief printing method of the present invention described above as one embodiment is preferable.

The film thickness of the hole injection layer is appropriately set in consideration of the required characteristics and the simplicity of the film forming process, and is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, more preferably 5 nm to 200 nm. is there.

<Hole transport layer>
As the hole transport material constituting the hole transport layer, polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine in a side chain or a main chain, a pyrazoline derivative, an arylamine derivative, a stilbene derivative, Triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polyarylamine or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) or derivative thereof, or poly (2,5-thienylene vinylene) or Examples thereof include derivatives thereof.

Among these, hole transport materials include polyvinyl carbazole or derivatives thereof, polysilane or derivatives thereof, polysiloxane derivatives having aromatic amine compound groups in the side chain or main chain, polyaniline or derivatives thereof, polythiophene or derivatives thereof, poly Preferred is a polymeric hole transport material such as arylamine or a derivative thereof, poly (p-phenylene vinylene) or a derivative thereof, or poly (2,5-thienylene vinylene) or a derivative thereof, more preferably polyvinyl carbazole or a derivative thereof. , Polysilane or a derivative thereof, and a polysiloxane derivative having an aromatic amine in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

The method for forming the hole transport layer is not particularly limited, but in the case of a low molecular hole transport material, film formation from a mixed solution containing a polymer binder and a hole transport material can be exemplified. Examples of molecular hole transport materials include film formation from a solution containing a hole transport material.

As a film formation method from a solution, the same coating method as the above-described film formation method of the hole injection layer can be exemplified.

As the polymer binder to be mixed, those that do not extremely inhibit charge transport are preferable, and those that weakly absorb visible light are preferably used. For example, polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, poly Examples thereof include vinyl chloride and polysiloxane.

The film thickness of the hole transport layer is set in consideration of the required characteristics and the simplicity of the film forming process, and is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, more preferably 5 nm to 200 nm. .

<Light emitting layer>
The light emitting layer is usually formed of an organic substance that mainly emits fluorescence and / or phosphorescence, or an organic substance and a dopant that assists the organic substance. The dopant is added, for example, in order to improve the luminous efficiency and change the emission wavelength. In addition, the organic substance which comprises a light emitting layer may be a low molecular compound or a high molecular compound, and when forming a light emitting layer by the apply | coating method, it is preferable that a light emitting layer contains a high molecular compound. The number average molecular weight in terms of polystyrene of the polymer compound constituting the light emitting layer is, for example, about 10 ³ to 10 ⁸ . Examples of the light emitting material constituting the light emitting layer include the following dye materials, metal complex materials, polymer materials, and dopant materials.

(Dye material)
Examples of dye-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds. Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, oxadiazole dimers, pyrazoline dimers, quinacridone derivatives, coumarin derivatives, and the like.

(Metal complex materials)
Examples of metal complex materials include rare earth metals such as Tb, Eu, and Dy, or Al, Zn, Be, Ir, Pt, etc. as a central metal, and oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline. Examples include metal complexes having a structure as a ligand, for example, iridium complexes, platinum complexes and other metal complexes having light emission from a triplet excited state, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc A complex, a benzothiazole zinc complex, an azomethylzinc complex, a porphyrin zinc complex, a phenanthroline europium complex, and the like can be given.

(Polymer material)
As polymer materials, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, the above dye materials and metal complex light emitting materials are polymerized. The thing etc. can be mentioned.

Among the luminescent materials described above, materials that emit blue light include distyrylarylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

In addition, examples of materials that emit green light include quinacridone derivatives, coumarin derivatives, and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and the like. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

Examples of materials that emit red light include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, polyfluorene derivatives and the like are preferable.
(Dopant material)
Examples of the dopant material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squarylium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like. Note that the thickness of such a light emitting layer is usually about 2 nm to 200 nm.

Examples of the method for forming the light emitting layer include a method of forming a film from a solution, a vacuum deposition method, and a transfer method.

As a method of applying a solution in film formation from a solution, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a slit coating method Coating methods such as capillary coating method, spray coating method and nozzle printing method, and gravure printing method, screen printing method, relief printing method (flexographic printing method), offset printing method, reverse printing method, inkjet printing method, etc. The relief printing method of the present invention described above as one embodiment is preferable.

<Electron transport layer>
As the electron transport material constituting the electron transport layer, known materials can be used, such as oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthra Quinodimethane or derivatives thereof, fluorenone derivatives, diphenyldicyanoethylene or derivatives thereof, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof, etc. Can be mentioned.

Among these, electron transport materials include oxadiazole derivatives, benzoquinone or derivatives thereof, anthraquinones or derivatives thereof, metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorenes Or a derivative thereof, preferably 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline. preferable.

There are no particular restrictions on the method for forming the electron transport layer, but for low molecular weight electron transport materials, vacuum deposition from powder or film formation from a solution or a molten state can be exemplified. Examples of the material include film formation from a solution or a molten state. In the case of forming a film from a solution or a molten state, a polymer binder may be used in combination. Examples of the method for forming an electron transport layer from a solution include the same film formation method as the method for forming a hole injection layer from a solution described above.

The film thickness of the electron transport layer is appropriately set in consideration of the required characteristics and the simplicity of the film forming process, and is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, more preferably 5 nm to 200 nm. .

<Electron injection layer>
As a material constituting the electron injection layer, an optimal material is appropriately selected according to the type of the light emitting layer, and an alloy containing one or more of alkali metals, alkaline earth metals, alkali metals and alkaline earth metals, Alkali metal or alkaline earth metal oxides, halides, carbonates, mixtures of these substances, and the like can be given. Examples of alkali metals, alkali metal oxides, halides, and carbonates include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride , Rubidium oxide, rubidium fluoride, cesium oxide, cesium fluoride, lithium carbonate, and the like. Examples of alkaline earth metals, alkaline earth metal oxides, halides and carbonates include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, barium oxide, Examples thereof include barium fluoride, strontium oxide, strontium fluoride, and magnesium carbonate. The electron injection layer may be composed of a laminate in which two or more layers are laminated, and examples thereof include LiF / Ca. The electron injection layer is formed by vapor deposition, sputtering, printing, or the like. The thickness of the electron injection layer is preferably about 1 nm to 1 μm.

<Cathode>
A material for the cathode is preferably a material having a low work function, easy electron injection into the light emitting layer, and high electrical conductivity. Moreover, in the organic EL element of the structure which takes out light from an anode side, in order to reflect the light emitted from a light emitting layer to an anode side with a cathode, the material with a high visible light reflectance is preferable as a material of a cathode. As the cathode, for example, an alkali metal, an alkaline earth metal, a transition metal, a Group 13 metal of the periodic table, or the like can be used. Examples of the cathode material include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and the like. A metal, two or more alloys of the metals, one or more of the metals, and one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin An alloy, graphite, or a graphite intercalation compound is used. Examples of alloys include magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, calcium-aluminum alloys, and the like. it can. As the cathode, a transparent conductive electrode made of a conductive metal oxide, a conductive organic material, or the like can be used. Specifically, examples of the conductive metal oxide include indium oxide, zinc oxide, tin oxide, ITO, and IZO, and examples of the conductive organic substance include polyaniline or a derivative thereof, polythiophene or a derivative thereof, and the like. The cathode may be composed of a laminate in which two or more layers are laminated. The electron injection layer may be used as a cathode.

The thickness of the cathode is appropriately set in consideration of the required characteristics and the simplicity of the film forming process, and is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

Examples of the method for producing the cathode include a vacuum deposition method, a sputtering method, and a laminating method in which a metal thin film is thermocompression bonded.

(Preparation of letterpress printing plate)
First, a relief printing plate having the same configuration as the relief printing plate schematically shown in FIG. 1 was prepared. Using a polyester resin as a photosensitive resin, a relief printing plate 12 having a plurality of convex portions 11 having a plurality of depressions 14 formed by a photolithography method was produced. The width L1 of each convex part 11 in the width direction is 80 μm, and the height L3 of the convex part 11 is 136 μm. The distance L2 between the convex portion 11 and the convex portion 11 is 220 μm. The depth of each recess 14 is about 10 μm. Each depression 14 was formed so as to be arranged at a lattice point position of a square lattice, and 536 depressions were formed per inch. The ratio of the area of the depression 14 to the area of the top surface of the projection 11 (the area of the depression / the area of the projection) × 100 was about 70% in plan view.

(Preparation of substrate)
A transparent glass plate having a size of 200 mm (length) × 200 mm (width) × 0.7 mm (thickness) was prepared as an object to be coated.

(Preparation of organic EL ink)
A mixed solvent comprising 90 parts by weight of anisole and 10 parts by weight of cyclohexylbenzene was prepared, and an organic light emitting material was dissolved in the mixed solvent at a concentration of 1% by weight to prepare an organic EL ink. As the organic light emitting material, a polymer light emitting material (trade name “Green 1300” manufactured by Sumation Co., Ltd.) was used. The viscosity of the prepared organic EL ink was 25 cP (0.025 Pa · s).

(printing)
Printing was performed using a “printed printing experimental apparatus” manufactured by Dainippon Screen Mfg. Co., Ltd., which operates in the same manner as the printing apparatus schematically shown in FIG. The relief printing plate 12 produced above was used for the relief printing plate. The relief printing plate 12 was placed on the plate cylinder so that the extending direction of the projections 11 coincided with the circumferential direction of the plate cylinder. As described above, first, using a slit nozzle (slit width 220 mm, slit gap 50 μm), the organic EL ink is supplied to the transfer roll 23 (see FIG. 3) whose surface is made of chromium oxide, and the surface of the transfer roll 23 is organically coated. A thin film of EL ink was formed. Further, the relief printing plate 12 is pressed against the transfer roll 23 so that the projection 11 of the relief printing plate 12 is pressed into the transfer roll by 20 μm, and the transfer roll 23 contacts the projection 11 of the relief printing plate 12. The organic EL ink was transferred. Next, the relief printing plate 12 was pressed against the glass substrate so that the projection 11 of the relief printing plate 12 was pressed into the glass substrate by 20 μm. Thereafter, the organic EL ink was dried to obtain a plurality of strip-shaped thin films.

(Measurement of thin film shape)
The cross-sectional shape of the formed thin film was measured using a stylus film thickness meter (manufactured by KLA-Tencor; Alpha Step P16). The cross-sectional shape of the thin film cut along a plane perpendicular to the extending direction of the thin film was a dome shape. The width in the width direction was 210 μm and the film thickness was 59 nm.

(Comparative example)
A thin film was formed in the same manner as in the example except that a relief printing plate different from the relief printing plate 12 used in the example was used. In the examples, depressions were formed in the convex portions, but in this comparative example, a relief printing plate having no depressions in the convex portions was used. That is, a relief printing plate having a convex top surface was used. The relief printing plates used in the comparative example and the example have the same configuration except that no depression is formed in the projection.
(Film thickness measurement)
The shape of the thin film was measured in the same manner as in the example. The cross section of the thin film was dome-shaped. The width of the thin film in the width direction was 210 μm, and the film thickness was 53 nm. Compared with the thin film of an Example, the thin film with a thin film thickness was formed.

As described above, it was confirmed that the amount of the organic EL ink to be printed can be adjusted by forming a depression on the surface of the convex part, and as a result, the film thickness of the thin film to be formed can be adjusted. .

DESCRIPTION OF SYMBOLS 11 Convex part 12 Letterpress printing plate 14 Indentation 21 Printing apparatus 22 Ink supply source 23 Transfer roll 24 Plate cylinder 25 Slit nozzle 26 Cleaning mechanism 27 Printed object 28 Conveyance table

Claims

A relief printing plate used in a relief printing method using a transfer roll having a flat surface,
A relief printing plate having a convex portion with a predetermined depression formed on the surface.
The relief printing plate according to claim 1, wherein the projection has a plurality of the depressions arranged to be point-symmetric.
2. The relief printing plate according to claim 1, wherein the relief printing plate has a plurality of the protrusions extending in a predetermined direction at predetermined intervals.
4. The relief printing plate according to claim 3, wherein the convex portion has the depression extending in the predetermined direction or the depression extending in a direction perpendicular to the predetermined direction.
An ink source;
A transfer roll having a flat surface to which ink is supplied from the ink supply source;
The relief printing plate according to any one of claims 1 to 4, wherein the ink supplied to the surface of the transfer roll is transferred,
A printing apparatus comprising:
Supplying ink to a transfer roll having a flat surface;
Pressing the relief printing plate according to any one of claims 1 to 4 against the transfer roll, and transferring the ink to the relief printing plate;
Pressing the relief printing plate against a printing medium and printing the ink; and
Solidifying the ink and forming a thin film on the substrate,
A method for producing a thin film comprising:
A method for producing an organic EL element comprising a pair of electrodes and an organic EL layer provided between the electrodes,
Forming one of the pair of electrodes;
Supplying an organic EL ink containing a material to be the organic EL layer to a transfer roll having a flat surface;
Pressing the relief printing plate according to any one of claims 1 to 4 to the transfer roll, and transferring the organic EL ink to the relief printing plate;
Pressing the relief printing plate against a pair of the one electrodes and printing the organic EL ink;
Solidifying the organic EL ink and forming an organic EL layer on the one electrode;
Forming the other of the pair of electrodes on the organic EL layer;
The manufacturing method of an organic EL element provided with.