JP6531319B2 - Display device manufacturing method - Google Patents

Description

  The present invention relates to a method of manufacturing a display device such as an organic EL display, and more particularly to a method of manufacturing a display device which is curvably thinned.

  BACKGROUND Conventionally, display devices using flat panel displays such as liquid crystal displays and organic EL displays are used in various applications. In particular, in recent years, flexible displays have attracted attention from the viewpoint of design. When manufacturing a flexible display, an organic EL display that easily handles bending is often employed.

  A conventional organic EL display seals a display element such as an organic EL element using a glass substrate such as a cap glass. The airtightness and water tightness of the organic EL element were maintained by the glass substrate, and the deterioration of the element due to oxygen and moisture was prevented. However, in recent years, an organic EL display using a resin substrate has been developed in response to demands for further thinning and curving as described above. A resin substrate has high flexibility compared to a glass substrate, is not easily damaged even if it is curved, and has a gas barrier property equivalent to that of a glass substrate by sealing a display element with a laminated structure of an inorganic film and an organic film. It was supposed to be possible to achieve.

  However, the resin substrate formed thin enough to be bendable is very difficult to handle in the manufacturing process, and as a result, the yield may be deteriorated. Therefore, conventionally, an organic resin film such as polyimide is formed on a supporting glass to facilitate handling in the manufacturing process. A display element such as a functional film is formed on the organic resin film in a state where the rigidity of the whole substrate is secured by the supporting glass, and after sealing treatment is performed, the organic resin film is peeled from the supporting glass (for example, patent document 1)). The work of peeling the organic resin film from the supporting glass has been performed by removing the peeling layer previously formed between the supporting glass and the organic resin film by a laser device.

JP, 2016-004112

  However, in the above-described method, there is a possibility that the laser irradiation at the time of peeling the supporting glass may adversely affect the display element. In addition, it is necessary to introduce an expensive manufacturing apparatus such as an excimer laser, and the production cost is also increased. In particular, in recent years, although a plurality of display devices are manufactured in a state of being chamfered on a large substrate, the irradiation area of the laser increases as the substrate becomes larger, so that the production efficiency may decrease or peeling defects may occur. It had increased.

  In addition, it is difficult to sufficiently protect the display element in a display device constituted only by a resin film, and the reliability may not be sufficient. In particular, in the organic EL display, the deterioration of the display element is an obstacle to the long life, and a highly reliable substrate for preventing the entry of moisture and oxygen from the outside has been required.

  An object of the present invention is to provide a display device that can be bent by a simple method without peeling off the organic resin film and the glass substrate.

  The display device manufacturing method according to the present invention includes the steps of forming an organic resin film on the first main surface of a glass substrate, forming a layer including a display element on the organic resin film, and an organic resin film. The method includes thinning the glass substrate by etching the second principal surface side while covering the first principal surface side of the glass substrate with the etching resistant member.

  In the step of forming an organic resin film on a glass substrate, for example, an organic resin film is coated on a glass substrate using a coating apparatus such as a slit coater on a conventionally used support glass. It is preferable to use a polyimide as the organic resin film. In the step of forming the display element, a functional layer including a thin film transistor, a light emitting layer of an organic EL, and the like is formed on the organic resin film. After such a display element is formed, the display element is sealed so as not to be exposed to the open air. In the sealing step, sealing treatment with a resin film in which an inorganic film and an organic film are alternately stacked is performed. After the sealing process, the resin film is coated with a film or resist having etching resistance, and the glass substrate is etched. The etching treatment is performed by bringing the etching solution into contact with the main surface on which the glass substrate of the display device is disposed, so as to reduce the thickness of the glass substrate.

  In the present invention, since the glass substrate is not used as a supporting glass for the convenience of the manufacturing process but used as a part of a component of the display device, peeling between the glass substrate and the organic resin film is unnecessary. There is. Furthermore, since the glass substrate is thinned by etching, the problem that the thickness of the display device does not occur does not occur even if the resin film is not peeled off from the supporting glass, and the entire glass substrate can be curved as needed. . Further, since the display element is protected by the organic resin film and the glass substrate, there is less possibility that the display element is exposed to the outside air to be deteriorated, and thus the reliability of the display device is improved.

  Furthermore, the glass substrate is preferably thinned to such an extent that the display device can be curved. The glass substrate is preferably thinned to 50 to 150 μm. By etching the glass substrate to this range, it is possible to curve even a display including the glass substrate.

  Further, the etching of the glass substrate is performed by spraying an etching solution onto the glass substrate. With this configuration, the etching solution is less likely to be in contact with other regions of the display device other than the glass substrate, and thus there is little possibility that the display element is degraded by moisture.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the display apparatus which can be curved by a simple method, without peeling with an organic resin film and a glass substrate.

It is a figure showing composition of a display concerning one embodiment of the present invention. It is a figure which shows the manufacturing process of a display apparatus. It is a figure which shows the etching apparatus used in this embodiment.

  From here, the display device according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic side view of an organic EL panel 10. The organic EL panel 10 has a support glass 12, a polyimide film 14, a transparent electrode layer 16, a light emitting layer 18 and a sealing layer 20.

  The support glass 12 is disposed on the side opposite to the side where the user views the image, and the polyimide film 14 is formed on one main surface. In the present embodiment, the polyimide film 14 corresponds to the organic resin film in the claims. In the present embodiment, polyimide is used as the organic resin film, but there is no particular limitation as long as it is a resin film that can withstand the processing temperature of the film forming process.

  The transparent electrode layer 16 and the light emitting layer 18 are sequentially laminated on the polyimide film 14. It is preferable to form a known low temperature polysilicon film as the transparent electrode layer 16. The light emitting layer 18 includes functional layers such as a hole transport layer, an organic EL element, and an electron transport layer. In the present embodiment, the transparent electrode layer 16 and the light emitting layer 18 correspond to the display element in the claims. The sealing layer 20 covers the light emitting layer 18 and is configured to prevent the light emitting element and the like from being exposed to moisture and oxygen of the open air and deteriorating. Usually, the sealing layer 20 is formed by laminating resin films having different compositions. In the present embodiment, thin film sealing is performed by five sealing layers, but the configuration of the sealing layer 20 can be changed as appropriate. The organic EL panel 10 is a top emission system configured to visually recognize an image from the side where the sealing layer 20 is disposed.

  From here, the manufacturing method of the organic electroluminescent panel 10 is demonstrated using FIG. 2 (A)-(D). First, the process of forming the polyimide film 14 on the support glass 12 will be described. A polyimide precursor dissolved in a solvent such as dimethyl acetamide or methyl pyrrolidone is applied onto the supporting glass 12 (see FIG. 2A). The support glass 12 can use what is used by the well-known manufacturing method, and it is preferable to have a plate | board thickness of 300-800 micrometers. The polyimide precursor can be applied by a coating device such as a slit coater or a roll coater. Under the present circumstances, it is preferable to apply | coat so that the thickness of the polyimide film 14 may be 7-30 micrometers. The polyimide precursor is cured by being introduced into a drying furnace heated to a predetermined temperature. In addition, before applying the polyimide film 14 on the supporting glass 12, a primer layer may be formed to increase the adhesion.

  After the polyimide film 14 is formed, the transparent electrode layer 16 is formed on the polyimide film 14. In the present embodiment, a low temperature polysilicon film is formed on the polyimide film 14 by a known method such as sputtering. The light emitting layer 18 is formed on the transparent electrode layer 16 (see FIG. 2B). The light emitting layer 18 can be formed of a known organic material using a known method such as a vapor deposition method or an inkjet method. The light emitting layer 18 includes not only the light emitting layer made of an organic material but also a hole transporting layer and an electron transporting layer, and in the present embodiment, the hole transporting layer, the light emitting layer, the electron transporting on the transparent electrode layer 16 Layers are stacked sequentially.

  The transparent electrode layer 16 and the light emitting layer 18 are coated by laminating a plurality of sealing layers 20 (see FIG. 2C). The sealing layer 20 is a resin film having gas barrier properties, and is configured to maintain the airtightness and water tightness of the light emitting layer 18. The sealing layer 20 can protect the light emitting layer 18 more effectively by alternately laminating an inorganic film and an organic film. In this embodiment, although thin film sealing is performed by five layers of sealing layers, it is possible to change a lamination structure suitably.

  As the inorganic film in the sealing layer, silicon nitride, silicon oxide, silicon oxynitride, carbon monoxide, carbon nitride, aluminum oxide or the like can be used. As the organic film, polyester, methacrylic, polystyrene, transparent fluorine resin, polyimide, polyurethane, cycloolefin copolymer, acrylic resin, epoxy resin and the like can be used. In addition, in order to ensure the visibility of a display apparatus, as for these sealing layers, it is preferable that the total light transmittance is 90% or more.

  The thin film-sealed organic EL panel 10 performs a thinning process of the support glass 12 by etching (see FIG. 2D). The etching process is preferably performed by bringing an etchant containing at least hydrofluoric acid into contact with the supporting glass 12. From here, the etching method of the support glass 12 is demonstrated.

  First, the sealing layer 20 is covered with the protective film 22 before the etching process is performed. The protective film 22 is made of a member resistant to the etching solution, and at least resistant to hydrofluoric acid. In the present embodiment, the film member protects the film, but it is also possible to use an etching resistant paint such as a resist. In addition, when the sealing layer 20 disposed on the outermost surface has acid resistance, the protective film 22 may not be used.

  In order to etch the support glass 12, it is preferable to use a single-wafer etching apparatus 30 as shown in FIG. 3 (A). The etching apparatus 30 has at least a transport roller 32 and a spray unit 34. The transport roller 32 is disposed along the length direction of the etching device 30 and configured to transport the organic EL panel 10. At this time, the support glass 12 is placed so as to be in contact with the transport roller 32 (see FIG. 3B).

  The spray unit 34 is disposed below the transport roller 32 and is configured to spray the etchant toward the support glass 12. The spray unit 34 has a plurality of spray nozzles so as to spray the etchant uniformly onto the support glass 12. The etching solution contains at least hydrofluoric acid, and if necessary, an inorganic acid such as hydrochloric acid or a surfactant may be added.

  In addition, it is preferable that the cleaning liquid is sprayed from a spray unit disposed at a position near the loading unit and the unloading unit of the etching apparatus to clean the support glass 12. Although the cleaning liquid of this embodiment uses city water, it is not limited to this.

  The protective film 22 is peeled off after the etching process is performed. The protective film 22 can be peeled off by applying physical force. When a resist material is used, it can be peeled by immersion in a peeling solution or the like, but it should be treated in a short time so as not to affect the display element.

  While the support glass 12 is conveyed in the horizontal direction by the conveyance roller 32, the thinning processing is performed by the etching liquid sprayed from the spray unit 34. In the present embodiment, the etching liquid does not contact the organic EL panel 10 more than necessary by spraying the etching liquid from below onto the support glass 12 disposed downward. When the etching solution comes in contact with the support glass 12, the etching solution drops as it is and is stored in a recovery tank (not shown) or the like.

  Further, the jetting pressure of the etching solution and the distance between the spray unit 34 and the organic EL panel 10 can be appropriately adjusted, and the etching solution is configured not to scatter in the region other than the support glass 12. When the etching solution is in contact with the organic EL panel 10 for a long time, the moisture of the etching solution gradually penetrates, and the light emitting layer 18 may be deteriorated by the moisture. For this reason, it is necessary to protect the light emitting layer 18 more reliably by increasing the number of layers of the sealing layer 20, which causes an extra cost and increases the thickness of the organic EL panel 10. Occur.

  Moreover, when thinning the support glass 12, it is preferable to etch so that the plate thickness of the support glass 12 may be 50-200 micrometers. By etching the support glass 12 to this range, it is possible to have the same degree of flexibility as an organic EL display composed only of a resin film. For example, an 8-inch organic EL display 10 in which the support glass 12 is etched to 100 μm can be curved to a curvature radius of about 300 mm. Further, the radius of curvature that can be bent can be reduced by further etching.

  Moreover, since the organic EL panel 10 is conveyed by the conveyance roller 32, even if the support glass 12 becomes thin, it can be handled stably. Furthermore, if the thickness of a normal glass substrate is reduced to 100 μm or less, there may be a problem such as bending during etching, but the strength of the entire organic EL panel 10 is caused by the polyimide film 14 and the sealing layer 20 etc. Therefore, the risk of the supporting glass 12 being broken during the etching process can be reduced. If a problem occurs during conveyance due to thinning of the support glass 12, the pressure for jetting the etching solution may be reduced or the distance between the conveyance rollers may be narrowed. If it is difficult to control the etching apparatus, it is preferable to further dispose a support substrate having acid resistance on the top of the protective film 22.

  Such a display device is usually manufactured in many cases in which a plurality of display devices are chamfered on a large substrate. In this case, a process of dividing the large substrate into each substrate is performed after the etching process. A parting process can use a scribing apparatus, a laser apparatus, or the like. Since the support glass 12 is thinned by the etching process, the support glass 12 can be easily divided even if a laser device conventionally used for dividing a resin substrate is used.

  In the present embodiment, it is not necessary to peel off the polyimide 14 from the support glass 12 with almost no need to change the conventional manufacturing process. The flexible glass can be manufactured while the supporting glass 12 is disposed as a part of the organic EL panel 10, so that the production efficiency is improved. Furthermore, the presence of the support glass 12 makes it possible to protect the light emitting layer 18 more reliably.

  The above description of the embodiments should be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated not by the embodiments described above but by the claims. Further, the scope of the present invention is intended to include all modifications within the scope and meaning equivalent to the claims.

10-organic EL panel 12-supporting glass 14-polyimide film 16-transparent electrode layer 18-light emitting layer 20-sealing layer 22-protective film 30-etching device 32- conveying roller 34-spray unit

Claims (2)

A display device manufacturing method for manufacturing a display device for displaying an image using a display element, comprising:
Forming an organic resin film on the first main surface of the glass substrate;
Forming a layer including a display element on the organic resin film;
After forming the layer including the display element, the second major surface side is etched while covering the first major surface side of the glass substrate including the organic resin film with an etching resistant member so that bending is possible Thinning the glass substrate to a desired thickness;
Only including,
The display apparatus manufacturing method whose thickness which becomes free to bend is 50-200 micrometers .   The display device manufacturing method according to claim 1, wherein in the step of thinning the glass substrate, etching is performed by spraying an etching solution on the glass substrate.

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