JP3138967U - Organic electroluminescence element and display device using the same - Google Patents

Abstract

An organic EL element which is low in cost and has a long lifetime is provided.
An organic EL element is sealed with a laminate film. At least on the cathode side, preferably both the cathode side and the insulating substrate side are covered and laminated. It can be sealed with a low-cost laminator without using heat curing or UV curing of the adhesive.
[Selection] Figure 1

Description

  The present invention relates to an organic electroluminescence element and a display device using the same, and more particularly, to an organic electroluminescence element that realizes a long life and thinning of a light emitting element and has improved flexibility, and a display device using the same. .

  In an organic electroluminescence (Electro Luminescence: hereinafter, organic EL) element, it is necessary to seal in the final step in order to protect it from external damage.

  In conventional sealing, an adhesive is applied to a can or glass and attached to a substrate and exposed to ultraviolet rays, or cured by a method such as heating to blow off the solvent.

  In the organic EL element, the organic EL layers such as the hole transport layer, the light emitting layer, and the electron transport layer made of an organic EL material are particularly vulnerable to oxygen and moisture entering from the outside, and sufficient light emission time cannot be obtained due to these damages. Therefore, various sealing methods have been proposed.

  As described above, the conventional sealing process using a sealing can or sealing glass requires a device for applying an adhesive, a photosensitive device, and a drying device, and the adhesive itself has severe storage and storage conditions and high cost. there were.

  When a sealing can or sealing glass is used, a glass substrate is generally employed as the insulating substrate on which the organic EL layer is formed. And the sealing can and the sealing glass need a space for putting the hygroscopic material in it, and in order to prevent physical destruction of the sealing, it is equal to or more than the glass substrate on which the film is formed. I had to use a thick material.

  For this reason, the organic EL element becomes expensive, and further, there are problems such as thinning, which is originally an advantage of using an organic EL material, and loss of flexibility.

  The present invention has been made in view of the above-described problems. First, a hole transport layer, a light emitting layer, and an electron transport layer are provided between an insulating substrate provided with a transparent electrode and a cathode. And a sealing film that covers the cathode and seals the light emitting element.

  Moreover, another sealing film is provided on the sealing film.

  In addition, another sealing film is provided on the insulating substrate side.

  Further, the light emitting layer is a material having a high molecular weight molecular weight.

  Further, a hygroscopic material is disposed between the cathode and the sealing film.

  2ndly, it is an organic electroluminescence display provided with the display part which displays information by light emission of an organic electroluminescent element, and the control part which controls a display part, Comprising: The said electroluminescent element is transparent with an insulating board | substrate. The problem is solved by having a light emitting element composed of an electrode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode, and a sealing film for sealing the light emitting element.

  Further, the sealing film covers both surfaces of the light emitting element.

  Further, the light emitting layer is a material having a high molecular weight molecular weight.

  Further, a hygroscopic material is disposed between the cathode and the sealing film.

  According to the present invention, first, since the light emitting element is sealed with a film-like plastic (laminate film), the deterioration of the organic EL layer can be prevented and the life of the organic EL element and the display device can be extended.

  Secondly, by using a film-like plastic as the sealing material and thermocompression bonding with a laminator, an apparatus for applying and curing the adhesive and the adhesive itself become unnecessary, and a significant cost reduction can be realized.

  Third, since the sealing material is in the form of a film, the thickness of the completed organic EL element can be made as thin as the substrate (light emitting element) on which the film is formed, and the organic EL material should be used originally. The organic EL element which realized the thinning which is the advantage by can be implement | achieved.

  Fourth, by adopting a film-like plastic for the substrate on which the organic EL layer is formed, an organic EL element that fully utilizes the advantage of the organic EL layer, which is flexible, can be realized.

  An embodiment of the present invention will be described in detail with reference to FIGS.

  1A and 1B are diagrams showing an EL element 1 of the present invention, in which FIG. 1A is a cross-sectional view and FIG. 1B is an exploded perspective view of FIG.

  The EL element 1 of the present invention is composed of a light emitting element 2 and a sealing film 3.

  In the light emitting element 2, an EL layer 23 is disposed between an insulating substrate 21 provided with a transparent electrode 22 and a cathode 24. Here, as an example, a configuration is shown in which a transparent electrode 22 is provided on an insulating substrate 21, an EL layer 23 is formed thereon, and a cathode 24 is provided on the EL layer 23. The EL layer 23 is formed by laminating a hole transport layer 231, a light emitting layer 232, and an electron transport layer 233 in this order.

  The insulating substrate 21 is, for example, a film-like plastic (thickness of about 0.1 mm), and the transparent electrode 22 is, for example, ITO (Indium Tin Oxide). The insulating substrate 21 may be a glass substrate (thickness of about 0.2 mm to 0.8 mm).

  The hole transport layer 231 constituting the EL layer 23 is formed with PEDOT (polyethylenedioxythiophene), and the light emitting layer 232 is formed with a polymer ink having a high molecular weight. The electron transport layer 233 is formed of lithium fluoride (LiF) and calcium (Ca).

  The sealing film 3 is a highly moisture-proof sheet-like laminate film (for example, “CELLA (registered trademark)” FM1550 manufactured by Kureha Co., Ltd.), and is provided so as to cover both surfaces of the light emitting element 2, for example. Specifically, the first laminate film 31 is disposed on one main surface side of the cathode 24 (on the cathode 24 in FIG. 1), and the second laminate film 32 is disposed on the first laminate film 31. . The third laminate film 33 is disposed on one main surface side of the insulating substrate 21 (under the insulating substrate 21 in FIG. 1). The ends of the first to third laminated films are thermocompression bonded, thereby sealing the light emitting element 2.

  Since the cathode 24 is formed by vapor deposition, the density of the film is thin instead of damaging the EL layer 23, and pinholes and the like are easily formed on the surface. That is, when the moisture or the like enters the cathode 24 side, the EL layer 23 deteriorates. Therefore, in this embodiment, the moisture resistance on the cathode 24 side can be improved by providing the double laminate films 31 and 32 on the cathode 24. Furthermore, by providing the laminate film 33 also on the insulating substrate 21 side, the moisture resistance can be further improved.

  A hygroscopic material 25 is provided between the first laminate film 31 and the cathode 24. The hygroscopic material is obtained, for example, by applying a liquid to a sheet and drying it. If there is no problem in characteristics, the hygroscopic material 25 may not be disposed.

  Since the thickness of each of the laminate films 3 is about 0.1 mm, in the case of FIG. 1, the total thickness of the insulating substrate 21, the laminate film 3, and the hygroscopic material 25 is about 0.5 mm.

  When a glass substrate is used as the insulating substrate on which the transparent electrode is formed and sealing is further performed with sealing glass (both having a thickness of about 0.7 mm), the total thickness of the organic EL element is 1. Although it is 4 mm, according to the present invention, the thickness of the organic EL element 1 can be greatly reduced. For example, even when a glass substrate having the same thickness as the conventional substrate (thickness 0.7 mm) is adopted as the insulating substrate 21, the total thickness is about 1.0 mm (1.1 mm when the moisture absorbent 25 is provided). Thinner than the conventional structure (glass substrate and sealing glass).

  Furthermore, since the insulating substrate 21 and the laminate film 3 are all flexible plastic films, the thin organic EL element 1 can be provided without impairing the flexibility characteristic of the organic EL layer.

  FIG. 2 is a diagram showing another embodiment of the present invention.

  Sealing with the laminate film 3 is not limited to that shown in FIG. For example, there are a case where the laminate film 3 is provided only on the cathode 24 side (FIG. 2A) and a case where the laminate film 3 is provided only on the cathode 24 side (FIG. 2B). In these cases, the laminate film 3 is thermocompression bonded to the insulating substrate 21. One sheet (FIG. 2C) may be provided on both the cathode 24 side and the insulating substrate 21 side.

  FIG. 3 is a flowchart showing a method for manufacturing the organic EL element 1 of the present embodiment. 4 to 7 are diagrams showing an example of the manufacturing process. Hereinafter, the manufacturing method will be described with reference to FIGS. 3 to 7 by taking the case of the organic EL element 1 shown in FIG. 1 as an example.

  First step (FIG. 3: step S1): After the insulating substrate 21 is cleaned, a transparent electrode 22 made of an ITO film is formed on the surface. In the following description, the insulating substrate 21 during the deposition of each layer will be described as the substrate I.

  Second Step (FIG. 3: Step S2, FIG. 4): As shown in FIG. 4A, the surface of the substrate I after being cleaned by the spin coater 51 is spin-coated with hydrogen peroxide and PEDOT. Then, the desired patterning is applied and dried (under reduced pressure at 200 ° C. for 10 minutes). Thereby, the hole transport layer 231 is formed on the transparent electrode 22 (FIG. 4B).

  Third step (FIG. 3: Step S3, FIG. 5): The light emitting layer 232 is formed on the hole transport layer 231. The light emitting layer 232 is formed by either a spin coating method (FIG. 5A) or an ink jet method (FIG. 5B) depending on the size of the element.

  In the case of the spin coating method, as shown in FIG. 5A, the substrate I after forming the hole transport layer 231 is put into the spin coater 51, spin coated with a polymer ink, patterned, and dried (under reduced pressure at 180 ° C. 60 minutes).

  On the other hand, in the case of the ink jet method, as shown in FIG. 5B, polymer ink is applied to the substrate I after the hole transport layer 231 is formed by the ink jet printer 52 and dried (under reduced pressure at 180 ° C. for 60 minutes).

  Thus, the light-emitting layer 232 is formed over the hole-transport layer 231 (FIG. 5C).

Fourth step (FIG. 3: step S4, FIG. 6): As shown in FIG. 6A, the substrate I after the formation of the light emitting layer 232 is put into a vacuum deposition apparatus, LiF and Ca are deposited, and the electron transport layer 233 is formed. Form. Subsequently, aluminum Al is vapor-deposited to form the cathode 24. The process from this step to the fifth step is performed in a nitrogen (N ₂ ) atmosphere or a vacuum atmosphere. Thus, the light emitting element 2 is formed (FIG. 6B).

  Fifth step (FIG. 3: step S5, FIG. 7): The moisture-absorbing material 25 is applied on the cathode 24 and then dried, or a sheet coated with the moisture-absorbing material is attached, and the light-emitting element 2 is covered with the laminate film 3 . Here, the first and second laminated films 31 and 32 are provided on the hygroscopic material 25 on the cathode 24 side, and the third laminated film 33 is provided on the insulating substrate 21 side. The substrate I covered with the laminate film 3 is put into a thermocompression laminator 54 using a roller (FIG. 7A), and the end of the laminate film 3 around the light emitting element 2 is thermocompression bonded (FIG. 7B). . When a plurality of laminate films 3 are used as shown in the figure, thermocompression bonding is performed for each laminate film.

  When the insulating substrate 21 is a plastic film, the time required for thermocompression bonding is about 1 minute. When the adhesive and heat or ultraviolet curing is performed as in the conventional case, sealing (application and curing) requires about 30 minutes, and therefore the time for sealing can be shortened. In addition, since it is less likely to be damaged than a glass substrate, handling during the manufacturing process is facilitated.

  The same applies to other sealing patterns of the laminate film 3 as shown in FIG. Further, for example, when the insulating substrate 21 is a glass substrate or the like, the insulating substrate 21 can be reliably sealed by thermocompression with the laminator 54 a plurality of times.

  Further, in order to obtain a reinforcing and moisture-proof effect, an adhesive such as silicon is applied to the surroundings. It is not necessary to provide an adhesive such as silicon.

  Thus, in this invention, the board | substrate I (light emitting element 2) after film-forming to the last stage is sealed with the laminate film 3. FIG. Thereby, the low-cost and flexible thin organic EL element 1 can be provided.

  8 and 9 are diagrams showing examples of the display devices 61 and 62 using the organic EL element 1 of FIG. FIG. 8 shows a case of a card-type non-contact tag 61, and FIG. 9 shows a case of a wristwatch-type non-contact tag 62. In each figure, (A) is a plan view and (B) is a cross-sectional view.

  Since the configurations of the display devices 61 and 62 are the same in both FIG. 8 and FIG. 9, the same components are denoted by the same reference numerals, and will be described below with reference to FIG.

  In the case 66, a support substrate 63 such as a glass epoxy substrate and an organic EL element 1 (see FIG. 1) in which the EL layer 23 is patterned in a 7-segment or dot matrix are arranged. The support substrate 63 is provided with a desired control circuit 64 and wiring (not shown) serving as a control unit of the organic EL element 1, and a flexible printed circuit 65 (Flexible Printed Circuits: FPC) connects the support substrate 63 and the organic EL element 1. Connecting. An antenna coil 67 is provided along the inner periphery of the case 66.

  The card-type non-contact tag 61 is employed in, for example, a system that receives and displays information input from a personal computer (hereinafter abbreviated as a personal computer) connected to a reader / writer. An example of the operation is as follows.

  Information input to the personal computer is transferred from the personal computer to a reader / writer (not shown) by serial communication. The reader / writer has an antenna coil and a control unit, converts information transferred by the control unit into a signal, and transmits the signal through the antenna coil 67. Specifically, it generates a magnetic field by electromagnetic induction and transmits a signal at a frequency of 125 kHz or 13.56 MHz.

  When the card-type non-contact tag 61 is brought close to the reader / writer, the antenna coil 67 built in the case 66 becomes an antenna due to the influence of the magnetic field of the reader / writer and becomes an antenna, and receives a signal transmitted by the reader / writer. In addition, since the operation power is supplied to the control circuit 64 and the organic EL element 1 by the magnetic field, a battery is not necessary.

Specifically, power is supplied to the control circuit 64, converts the received signal into information, and sends the information to the microcomputer. Subsequently, the microcomputer sends a display content instruction to the organic EL element 1 based on the information, and the information is displayed on the organic EL element 1.

It is (A) sectional drawing and (B) exploded perspective view of the organic EL element of this invention. It is sectional drawing which shows the other form of the organic EL element of this invention. It is a flowchart explaining the manufacturing method of the organic EL element of this invention. It is (A) schematic diagram and (B) sectional drawing explaining the manufacturing method of the organic EL element of this invention. It is (A) schematic diagram, (B) schematic diagram, (C) sectional drawing explaining the manufacturing method of the organic EL element of this invention. It is (A) schematic diagram and (B) sectional drawing explaining the manufacturing method of the organic EL element of this invention. It is (A) schematic diagram and (B) sectional drawing explaining the manufacturing method of the organic EL element of this invention. It is (A) top view and (B) sectional view showing a display of the present invention. It is (A) top view and (B) sectional view showing a display of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL element 2 Light emitting element 3 Laminated film 21 Insulating substrate 22 Transparent electrode 23 EL layer 24 Cathode 25 Moisture-proof material 31 1st laminated film 32 2nd laminated film 33 3rd laminated film 51 Spin coater 52 Inkjet printer 53 Vacuum deposition apparatus 54 Laminator 61, 62 Display device 63 Support substrate 64 Control circuit 65 FPC
66 Case 67 Antenna coil
231 Hole transport layer 232 Light emitting layer 233 Electron transport layer

Claims (9)

A light emitting device in which a hole transport layer, a light emitting layer, and an electron transport layer are provided between an insulating substrate provided with a transparent electrode and a cathode;
An organic electroluminescence element comprising: a film that covers the cathode and seals the light emitting element.   The organic electroluminescence device according to claim 1, wherein another film is provided on the film.   The organic electroluminescence element according to claim 1, wherein another sealing film is provided on the insulating substrate side.   The organic electroluminescence device according to claim 1, wherein the light emitting layer is a material having a molecular weight of high molecular weight.   The organic electroluminescence device according to claim 1, wherein a hygroscopic material is disposed between the cathode and the sealing film. A display unit for displaying information by light emission of the organic electroluminescence element;
An organic EL display device comprising a control unit that controls the display unit,
The electroluminescence device has a light emitting device comprising an insulating substrate, a transparent electrode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode, and a sealing film for sealing the light emitting device. Display device.   The display device according to claim 6, wherein the sealing film covers both surfaces of the light emitting element.   The display device according to claim 6, wherein the light emitting layer is a high molecular weight material.   The display device according to claim 6, wherein a hygroscopic material is disposed between the cathode and the sealing film.

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