JPWO2012169071A1 - ORGANIC LIGHT EMITTING DEVICE AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

A transparent conductive film formed so as to cover a bus line and a set of insulating films made of a metal material juxtaposed on a transparent substrate, and a region between the bus line and the insulating film and the bus line and the insulating film; An organic light emitting device comprising: an organic material layer formed by applying a solution containing an organic material onto a transparent conductive film.

Description

  The present invention relates to an organic light emitting device having an organic multilayer structure including an organic light emitting layer and a method for manufacturing the same.

  It is well known to form a bank on a substrate in order to manufacture an organic light emitting device such as an organic EL device including an organic multilayer structure (see Patent Documents 1 and 2). For example, in each organic EL element arranged in a matrix in an organic EL display device, an anode is formed on the substrate, and a concave opening is formed on the anode by a pair of banks. As the bank, an insulating material such as polyimide is used, and the surface of the bank has liquid repellency. For example, an organic material layer is formed in the opening between the banks by applying an organic material using an inkjet method. Then, the cathode is formed so as to be in contact with the organic material layer in the opening.

Japanese Patent No. 4567092 Special table 2010-504608 gazette

  However, in the organic light emitting device having the bank structure as described above, the bank is generally formed as an insulating film having almost no translucency. Therefore, since the light generated by driving the organic light emitting element is absorbed by the bank, there is a problem that the area of the region that guides the generated light to the outside is limited and power is consumed wastefully. That is, since the opening formed by the bank becomes a region that emits light to the outside as it is, the aperture ratio is lowered, and as a result, there is a problem that power consumption increases to obtain a desired light amount.

  Thus, the problem to be solved by the present invention is to provide the organic light emitting device capable of reducing the power consumption by increasing the aperture ratio by taking the above drawback as an example, and a method for manufacturing the same. Is the purpose.

  An organic light-emitting device according to claim 1 includes a transparent substrate, a set of bus lines and insulating films made of a metal material juxtaposed on the substrate, each of the bus lines and the insulating films, and the bus lines. A transparent conductive film formed so as to cover a region between the insulating film and an organic material layer formed by applying a solution containing an organic material on the transparent conductive film. It is a feature.

  According to a seventh aspect of the present invention, there is provided a method of manufacturing an organic light emitting device, comprising: a bus line and an insulating film forming step in which a set of a bus line and an insulating film made of a metal material are juxtaposed on a transparent substrate; Forming a transparent conductive film so as to cover a region between the bus line and the insulating film, and forming an organic material layer by applying a solution containing an organic material on the transparent conductive film And a step of performing.

  According to the organic light emitting device of the invention of claim 1 and the method of manufacturing the organic light emitting device of the invention of claim 7, a set of bus lines and insulating films are juxtaposed on the substrate, A transparent conductive film is formed so as to cover the region between the bus line and the insulating film, an organic material layer is formed by applying an organic material on the transparent conductive film, and the generated light is a metal material Therefore, the aperture ratio of the organic light emitting device can be improved as compared with the conventional device. In addition, since the generated light can be emitted more efficiently, the power consumption can be reduced than that of a conventional element in order to obtain a desired light amount.

It is sectional drawing which shows each process of the manufacturing method of an organic light emitting element as an Example of this invention. It is a top view which shows the state in which the anode was formed on the board | substrate with the bus line which makes several pairs. It is sectional drawing which shows the example which made the anode end part and the side surface of the bus line into the reverse taper shape. It is sectional drawing which shows that a bus line becomes reverse taper by an etching. It is sectional drawing which shows the 1st light emitting element and 2nd light emitting element which are adjacent. It is sectional drawing which shows the 1st light emitting element and 2nd light emitting element which are adjacent as another Example of this invention. It is sectional drawing which shows an organic light emitting element as another Example of this invention. It is sectional drawing which shows an organic light emitting element as another Example of this invention. It is a figure for demonstrating the wet pinning effect.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a method for manufacturing an organic light emitting device (organic EL device) to which the present invention is applied. The manufacturing method of FIG. 1 shows a method for manufacturing one organic light emitting element in a light emitting panel having a plurality of organic light emitting elements. As shown in FIGS. 1 (a) to 1 (d), this manufacturing method includes (a) a bus line and insulating film forming step, (b) an anode forming step, (c) a hole injection / transport layer forming step, and (d) coating. A light emitting layer forming step, and (e) a vapor deposition layer forming step.
(a) Bus line and insulating film forming step First, for example, a film made of AlNd (aluminum-neodymium alloy) as a material by sputtering on a transparent (including translucent) substrate 11 made of a glass plate having a thickness of 0.7 mm. After that, a resist is applied on the AlNd film by photolithography, and exposure and development are sequentially performed to transfer the mask pattern to the resist. Further, other than the portion to be left as a bus line by etching The AlNd film is removed. When the resist is removed on the substrate 11, the remaining AlNd film is obtained as the bus line 12 as shown in FIG. The bus line 12 has conductivity and is a power supply line to the anode 14 described later.

Next, a film is deposited and formed on the substrate 11 by sputtering using SiO ₂ as a material, and then a resist is applied onto the SiO ₂ film by photolithography, and exposure and development are performed to transfer the mask pattern to the resist. Further, the SiO ₂ film other than the portion to be left as a bus line by etching is removed. When the resist is removed on the substrate 11, the remaining SiO ₂ film is obtained as a line-shaped insulating film 13 as shown in FIG. The bus line 12 and the insulating film 13 are paired in the same shape and are arranged in parallel to each other, and a recess is formed between the bus line 12 and the insulating film 13.

  Although FIG. 1A shows only one set of bus lines 12 and insulating films 13, a plurality of sets of bus lines 12 and insulating films 13 are actually formed in parallel on the substrate 11. . For example, the thickness of each bus line 12 and the insulating film 13 is 150 nm, the width thereof is 50 μm, the distance between the pair of bus lines 12 and the insulating film 13 is 300 μm, and the pair of bus lines 12 The distance between the insulating film 13 and another set of bus lines 12 and the insulating film 13 adjacent thereto is 50 μm.

  In the process of this embodiment, the insulating film 13 is formed after the bus line 12 is formed. However, the bus line 12 may be formed after the insulating film 13 is formed first.

Further, FIG. 1A shows a cross section in the juxtaposition direction orthogonal to the extending direction of the bus line 12 and the insulating film 13, and this also applies to FIGS. 1B to 1D.
(b) Anode formation step A transparent film is deposited on the substrate 11 including the bus line 12 and the insulating film 13 by sputtering using IZO (indium zinc oxide) as a material, and then a resist is formed on the IZO film by photolithography. After being applied, exposure and development are sequentially performed to transfer the mask pattern to the resist, and the IZO film other than the portion to be left as the anode is removed by etching. When the resist is removed on the substrate 11, the remaining IZO film is obtained as a transparent anode 14 (transparent conductive film) as shown in FIG. 1 (b).

The anode 14 is formed so as to cover each of the pair of bus lines 12 and the insulating film 13 and a region (concave portion) sandwiched between the bus lines 12 and the insulating film 13, and between the bus line 12 and the insulating film 13. In the region, it is directly on the substrate 11. The thickness of the anode 14 is, for example, 180 nm. FIG. 2 is a top view of the substrate 11 in which a plurality of sets of bus lines 12 and insulating films 13 and an anode 14 are formed on the substrate 11.
(c) Hole injection / transport layer forming step First, the anode 14 is irradiated with UV / O ₃ (ultraviolet / ozone) using an excimer light irradiation device (not shown), and the IZO surface is cleaned as a pretreatment. Is done. After the pretreatment, an ink 15 having a fixed concentration of 1 wt% using PEDOT (3,4-ethylenedioxythiophene polymer) as a host and PSS (styrene sulfonic acid polymer) as a dopant in an inkjet apparatus is shown in FIG. As shown in the left figure of c), it is applied by dropping into a recess between the bus line 12 and the insulating film 13. The ink 15 is on the anode 14 between one end (the left end in the cross section of the anode 14 in FIG. 1C) and the other end (the right end in the cross section of the anode 14 in FIG. 1C). With the surface tension, the center is raised and raised so that it does not leak out from the end.

For example, as shown in FIG. 3, the cross-sectional shapes of the bus line 12 and the insulating film 13 are made narrower toward the substrate 11, and the end surface of the anode 14 is substantially continuous with the bus line 12 and the insulating film 13. Thus, the ink 15 can be prevented from leaking outside the end portion of the anode 14 by the wet pinning effect. In FIG. 3, both side surfaces of the bus line 12 and the insulating film 13 in the juxtaposition direction are inclined so as to narrow toward the substrate 11, but at least in the juxtaposition direction of the bus line 12 and the insulating film 13. It suffices that the non-opposing side surface is inclined so as to face the substrate 11. Moreover, about the inclined side surface of this bus line 12,
When the IZO film is etched with an etching solution such as aqua regia in the anode forming process, the AlNd of the bus line 12 is etched together with the IZO film. However, since the etching rate of AlNd is higher than that of IZO, the AlNd on the side surface of the bus line 12 As a result, as shown in FIG. 4, the side surface of the bus line 12 following the end surface of the anode 14 may be reversely tapered when viewed from the substrate 11.

Next, the ink 15 is vacuum-dried at a gas pressure of 0.1 to 50 Pa for 2 minutes using a vacuum drying apparatus (not shown), and baked by heat treatment at 230 ° C. for 1 hour. . As a result, a hole injection / transport layer 16 (organic material layer) in which the solvent of the ink 15 is evaporated and cured as shown in the right diagram of FIG. 1C is obtained. The thickness of the hole injection / transport layer 16 is, for example, 30 nm.
(d) Balq as a host by a coating emitting layer forming step ink-jet apparatus, 6wt% -Hex-Ir (phq ) 3 fixed concentration 2 wt% of the ink used as the dopant (6wt% -Hex-Ir (phq ) 3: Balq) 17 is applied by dropping into a recess between the bus line 12 and the insulating film 13 as shown in the left diagram of FIG. The ink 17 is in a state where the center of the hole injection / transport layer 16 is raised between one end and the other end so as not to leak out from the end. That is, the taper angle at the end is increased by the wet pinning effect, so that the ink 17 does not leak to the outside of the end at the end of the hole injection / transport layer 16.

Next, using a vacuum drying apparatus (not shown), the ink 17 is vacuum-dried for 2 minutes at a gas pressure of 0.1 to 50 Pa, and baked by heat treatment at 130 ° C. for 10 minutes. The As a result, an RG coating mixed layer 18 (organic material layer) is obtained as a red-green coating light-emitting layer cured by evaporation of the solvent of the ink 17 as shown in the right diagram of FIG. The thickness of the RG coating mixed layer 18 is 40 nm, for example.
(e) Deposition layer forming step First, the host PAND and the dopant DPAVBi are vacuum-deposited together on the RG coating mixed layer 18 by a vacuum deposition method so that the dopant becomes 6 wt%, and thereby the blue light emitting layer 19 has a thickness of, for example, 15 nm. Formed with thickness. Next, Alq ₃ (tris (8-hydroxyquinolino) aluminum) is vacuum-deposited on the blue light emitting layer 19 by a vacuum deposition method, whereby the electron transport layer 20 is formed with a thickness of, for example, 30 nm. Next, LiF (lithium fluoride) is vacuum-deposited on the electron transport layer 20 by a vacuum evaporation method, whereby the electron injection layer 21 is formed with a thickness of 1 nm, for example. Finally, Al (aluminum) is vacuum-deposited on the electron injection layer 21 by a vacuum evaporation method, whereby the cathode 22 is formed with a thickness of, for example, 80 nm. FIG. 1 (e) shows a blue light emitting layer 19, an electron transport layer 20, an electron injection layer 21, and a cathode 22 formed in this vapor deposition layer forming step.

  Thus, according to the present invention, (a) bus line and insulating film forming step, (b) anode forming step, (c) hole injection / transport layer forming step, (d) coated light emitting layer forming step, and (e ) An organic light emitting device is manufactured by a vapor deposition layer forming step.

In the embodiment described above, a metal material such as AlNd is used for the bus line 12, SiO ₂ is used for the insulating film 13, and the anode 12 of the transparent conductive film is formed on the bus line 12 and the insulating film 13. Since the layers are stacked, the light emitted from the organic light emitting layer is diffused by the bus line 12 and the insulating film 13, so that the aperture ratio of the organic light emitting element can be improved. For example, in the organic LED disclosed in Patent Document 2, an insulating bank material is used, and the bank material generally has a material that absorbs in the visible region, such as a polyimide material, and thus has a metal color of the cathode. Deteriorates appearance with respect to hue. Moreover, since there is an absorbing material in the visible region, the emitted light may be lost in the bank. On the other hand, in the above-described embodiment, a metal such as AlNd is used as the bus line 12 and SiO ₂ is used as the insulating film 13, so that the appearance is the same as the Al metal color of the cathode 22. Absent. Moreover, even if the emitted light is diffused by the bus line 12 and the insulating film 13, it is emitted from the organic light emitting element without being lost, so that a higher aperture ratio can be obtained than before. Furthermore, the electrical resistivity of the material of the bus line 12 is smaller than that of the material of the anode 14 and the anode 14 is in direct contact with the bus line 12, so that the organic light emitting device can be efficiently supplied with power. Furthermore, as described above, light emitted for increasing the aperture ratio can be emitted more efficiently, so that power consumption can be reduced compared to conventional devices in order to obtain a desired amount of light. In addition, in the light emitting panel, adjacent light emitting elements can be opposed to each other by the bus line of one light emitting element and the insulating film of the other light emitting element, so that the distance between the light emitting elements is shortened by the insulating film of the other light emitting element. Even in this case, it is possible to satisfactorily ensure the insulation characteristics between the elements.

  In the above-described embodiment, the hole injection / transport layer 16 is formed by dropping the ink 15 in the recess between the bus line 12 and the insulating layer 13, and the RG coating mixed layer 18 is formed by dropping the ink 17. However, the present invention is not limited to the formation of two layers using the wet pinning effect as described above, and only one layer or three or more layers are formed using the wet pinning effect. Also good.

  For example, as shown in FIG. 5, the first light-emitting element A of the light-emitting panel includes (a) a bus line and insulating film forming step, (b) an anode forming step, and (c) hole injection / transport as in the above-described embodiment. It is manufactured by a layer forming step, (d) a coating light emitting layer forming step, and (e) a vapor deposition layer forming step. The second light emitting element B adjacent to the first light emitting element A includes (a) a bus line and insulating film forming step, (b) an anode forming step, (c) a hole injection / transport layer forming step, and (e) a vapor deposition layer. Manufactured by a forming process. (e) The vapor deposition layer forming process is a process common to the first light emitting element A and the second light emitting element B, and each vapor deposition layer is continuously formed over the first light emitting element A and the second light emitting element B. . In the second light emitting element B, the layer formed by utilizing the wetting pinning effect is only the hole injection / transport layer 16, and (e) only blue light is emitted by the blue light emitting layer 19 formed by vapor deposition in the vapor deposition layer forming process. Obtained as a color. Further, in the light emitting panel shown in FIG. 5, the uneven state of the surface of the RG coating mixed layer 18 formed in the recess between the bus lines 12 of the first light emitting element A, or the bus line 12 of the second light emitting element B. The uneven state of the surface of the hole injection / transport layer 16 coated and formed in the recesses is absorbed by the formation of the blue light emitting layer 19, and the surface of the blue light emitting layer 19 is flattened. An electron transport layer 20, an electron injection layer 21, and a cathode 22 are formed flat for each light emitting element. However, as shown in FIG. 6, the blue light emitting layer 19, the electron transport layer 20, the electron injection layer 21, and the cathode 22 are uneven without absorbing the above uneven state in each of the first light emitting element A and the second light emitting element B. It may be formed in a shape.

  In the above embodiment, the bus line 12 and the insulating film 13 are formed on the substrate 11 for each light emitting element. However, as shown in FIG. 7, the insulating layer 32 of the first light emitting element A is the first. You may make it overlap with the bus line 34 of the 2nd light emitting element B adjacent to the light emitting element A. FIG. That is, in the first light emitting element A, the bus line 31 and the insulating layer 32 are formed on the substrate 11, and the width of the insulating layer 32 is longer than the width of the bus line 31. An anode 33 is formed so as to cover from the outer end portion of the bus line 31 to the intermediate portion of the insulating film 32. In the second light emitting element B, a bus line 34 having an inverted L-shaped cross section is formed on the substrate 11 so as to cover the end portion of the insulating film 32, and the same insulation as that of the insulating film 32 from the outer end portion of the bus line 34 is formed. An anode 35 is formed so as to cover the middle part of the film (not shown). By forming the insulating layer 32 between the first light emitting element A and the second light emitting element B that are adjacent to each other as described above, the insulating characteristics between the elements can be improved.

Furthermore, in the above-described embodiment, the bus line 12 is directly formed on the substrate 11. However, as shown in FIG. 8, after the raised layer 24 made of an insulating material such as SiO ₂ is formed on the substrate 11. The bus line 25 may be formed on the raised layer 24. In this way, the bus line 25 can be formed as a thin film from the bus line 12. The bus line 12 is shown as a power supply line in contact with the anode 14, but may be formed as a power supply line in contact with the cathode.

In addition, the board | substrate 11, the bus line 12, the insulating film 13, the anode 14, the hole injection / transport layer 16, the RG coating mixed layer 18, the blue light emitting layer 19, the electron transport layer 20, the electron injection layer 21, and the cathode in the above-described embodiment. Each material of 22 is not limited to what was mentioned above. The substrate 11 may be a transparent (including translucent) plastic substrate. As the material of the bus line 12, metals such as Al, Ag, Mo, Ti, Pt, Au, or alloys thereof can be used, and those having a particularly high light reflectance are suitable. The insulating film 13 is not limited to the transparent insulating material such as SiO ₂ described above, but may be an opaque insulating material such as a polyimide material. As the material of the anode 14, other metal oxides such as ITO can be used. Further, as the material of the hole injection / transport layer 16, other metal oxides such as Ag, Mo, Cr, and Ir that can drop ink can be used. The material of the light emitting layer such as the RG coating mixed layer 18 and the blue light emitting layer 19 may be any material that has a function of emitting light by generating an excited state by injecting and recombining holes and electrons. In the case of forming a light emitting layer by dropping, it is necessary to be a material capable of dropping ink. For example, the material of the electron injection layer 21 is preferably formed of barium, phthalocyanine, lithium fluoride, or a combination thereof. As a material of the cathode 22, for example, a metal oxide such as ITO or IZO may be used.

  Further, the method of forming each film, the width and thickness of each film, the heating temperature, the heating time, and the like in each step shown in the above-described embodiments are merely examples, and the present invention is not limited thereto.

  Furthermore, although the bus line and the insulating film are formed as a set, the bus line and the insulating film that form the set do not need to have the same cross-sectional shape, and do not need to have the same length in the line extending direction.

  Further, the above-described wetting pinning effect will be described. As shown in FIG. 9A, when the equilibrium contact angle of the solution 42 dropped on the surface of the member 41 having the corner portion of the bending angle α is θ. As shown in FIG. 9B, the solution 42 cannot pass through the corner until the contact angle becomes θ + α. This is because the contact angle is smaller than θ on the slope where the solution 42 has passed through the corner as shown in FIG. 9 (c). That is, the contact angle of the solution 42 is in the range of θ to θ + α, and the wet pinning effect is that the liquid repellency increases as the bending angle α increases.

  The organic light emitting device and the manufacturing method thereof of the present invention can be applied to a light emitting device of an organic EL display or an organic EL lighting device.

11 Substrate 12, 25, 31, 34 Bus line 13, 24, 32 Insulating layer 14, 33, 35 Anode 16 Hole injection / transport layer 18 RG coating mixed layer 19 Blue light emitting layer 20 Electron transport layer 21 Electron injection layer 22 Cathode

Claims (7)

A transparent substrate;
A set of bus lines and insulating films made of metal materials juxtaposed on the substrate;
A transparent conductive film formed to cover each of the bus line and the insulating film and a region between the bus line and the insulating film;
An organic material layer formed by applying a solution containing an organic material onto the transparent conductive film.   2. The organic light emitting device according to claim 1, wherein the organic material layer includes a hole injection / transport layer formed on the transparent conductive film as an anode.   3. The organic light emitting device according to claim 2, wherein the organic material layer includes the hole injection / transport layer and a light emitting layer formed on the hole injection / transport layer.   The organic light-emitting element according to claim 1, wherein the organic material is applied onto the transparent conductive film using an inkjet method.   2. The organic light emitting device according to claim 1, wherein at least non-facing side surfaces in the juxtaposition direction of the bus lines and the insulating film are inclined so as to face the substrate.   The organic light-emitting device according to claim 1, wherein an electron transport layer, an electron injection layer, and a cathode are sequentially stacked on the organic material layer by vapor deposition. A bus line and insulating film forming step of juxtaposing a set of a bus line and an insulating film made of a metal material on a transparent substrate;
Forming a transparent conductive film so as to cover each of the bus line and the insulating film, and a region between the bus line and the insulating film;
Forming an organic material layer by applying a solution containing an organic material onto the transparent conductive film.

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