WO2010125623A1 - Display device - Google Patents

Abstract

An organic EL display device (1) is provided with a plastic substrate (2) having flexibility, and an organic EL display element (11) formed on the plastic substrate (2). The organic EL display device (1) has a display region (21) and a frame region (22) disposed at the periphery of the display region (21). On the display region (21), a deformation preventing member (28) which eliminates deformation of the display region (21) is disposed.

Description

Display device

The present invention relates to a display device such as an organic EL display device.

In recent years, in the display field, display devices using plastic substrates, etc., which have great advantages over glass substrates in terms of flexibility, impact resistance, and light weight, have received much attention. It has the potential to create new displays that were possible.

In the case of forming a thin film device such as a thin display device, a technique has been proposed in which a thin film device is formed on a separately prepared support substrate and transferred to a desired substrate.

More specifically, first, a separation layer (light absorption layer) is formed on a glass substrate, and then a thin film device layer which is a transfer layer is formed. This thin film device layer has a TFT (thin film transistor; Thin FilmTransistor) element for a display device including a polysilicon layer. Next, the thin film device layer is bonded (adhered) to a transfer body (that is, a plastic substrate) made of a synthetic resin through an adhesive layer. Subsequently, after irradiating a laser beam from the back surface of a glass substrate, a glass substrate is peeled from a separated layer. Then, the thin film device layer is transferred to the transfer body by removing the remaining separation layer (see, for example, Patent Document 1).

Similarly, after an organic EL layer is formed on a glass substrate, the organic EL layer is bonded to a plastic substrate through an adhesive layer, irradiated with laser light from the back surface of the glass substrate, and then peeled off. Thus, a display device in which an organic EL layer is transferred to a plastic substrate is disclosed (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 10-125931 Japanese Patent Laid-Open No. 2004-349152

However, since a plastic substrate generally has a small Young's modulus, stress due to a difference in thermal expansion is generated particularly through a thermal process, and deformation such as warpage and undulation occurs in a display region of a display device using the plastic substrate. There was a problem. Further, in order to suppress this deformation, it is necessary to increase the thickness of the plastic substrate. However, if the thickness of the plastic substrate is increased, there is a problem that the display device cannot be reduced in thickness and weight.

Therefore, the present invention has been made in view of the above-described problems, and can effectively suppress the occurrence of deformation such as warping and swell, and can be reduced in size, thickness, and weight. It is an object to provide a display device that can be used.

In order to achieve the above object, a display device of the present invention includes a flexible plastic substrate and a display element formed on the plastic substrate, and includes a display area and a frame provided around the display area. And having a region. The display area is provided with a deformation preventing member for preventing the display area from being deformed.

According to this configuration, since the rigidity of the display area is improved, it is possible to effectively prevent the display area from being deformed such as warping or swell.

Further, in the frame area provided around the display area, no deformation preventing member is provided, and a flexible plastic substrate is provided. Accordingly, since the frame area provided around the display area can be bent, the frame area around the display area can be eliminated in plan view. Therefore, it is possible to provide a display device with a narrow frame having almost no frame on the display surface.

In addition, unlike the above-described conventional technology, it is not necessary to increase the thickness of the plastic substrate, so that the display device can be made thinner and lighter.

In the display device of the present invention, the thickness of the deformation preventing member may be 0.05 to 0.3 mm.

According to this configuration, it is possible to prevent the inconvenience that the thickness of the entire display device is increased in a state where the rigidity of the display area is sufficiently secured, and to reduce the thickness and weight of the display device.

In the display device of the present invention, the deformation preventing member may be formed of one type selected from the group consisting of glass, hard plastic, and metal.

According to this configuration, the deformation preventing member can be formed from an inexpensive and versatile material.

In the display device of the present invention, an adhesive layer may be provided on the display element, and a deformation preventing member may be provided via the adhesive layer.

According to this configuration, the deformation preventing member can be provided in the display area with a simple configuration.

In addition, the display device of the present invention has excellent characteristics that it can effectively prevent deformation and can reduce the size, thickness, and weight of the display device. Therefore, the display device of the present invention can be suitably used for a display device using an organic EL display element as a display element.

According to the present invention, it is possible to provide a display device that can effectively prevent the occurrence of deformation and can be made narrower, thinner, and lighter.

1 is a plan view of an organic EL display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 is a cross-sectional view taken along the line BB in FIG. It is a top view which shows the state which bent the frame area | region of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention. It is sectional drawing for demonstrating the manufacturing method of the organic electroluminescence display which concerns on embodiment of this invention.

Hereinafter, a display device according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment. In the present embodiment, an organic EL display device will be described as an example of the display device.

FIG. 1 is a plan view of an organic EL display device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line AA in FIG. 3 is a cross-sectional view taken along the line BB of FIG. 1, and FIG. 4 is a plan view showing a state in which the frame region of the organic EL display device according to the embodiment of the present invention is bent.

As shown in FIG. 1, the organic EL display device 1 includes, for example, a display area 21 including a plurality of pixels and a frame area 22 provided around the display area 21.

As shown in FIGS. 1 to 3, the frame area 22 includes a drive circuit area 24 provided with a driver section 23 and a terminal area 26 provided with wiring terminals 25 drawn out from the display area 21. It is prescribed.

As shown in FIGS. 1 and 2, an integrated circuit chip (or IC chip) 27 that is an electronic component connected to the wiring terminal 25 is provided in the terminal region 26.

Further, the organic EL display device 1 includes a plastic substrate 2 having a film-like flexibility (flexibility) made of a colorless and transparent resin film deposited at room temperature. As a material for forming the plastic substrate 2, for example, an organic material such as polyparaxylene resin, acrylic resin, or polyimide resin can be used.

The thickness of the plastic substrate 2 is preferably 3 to 20 μm. This is because if the thickness is less than 3 μm, sufficient mechanical strength may not be obtained, and if it is greater than 20 μm, the flexibility of the organic EL display device 1 may be reduced. .

Further, a display element layer including the first TFT element 4 and the like is formed on the plastic substrate 2. The display element layer includes a first TFT element 4 formed on the plastic substrate 2, an interlayer insulating film 5 such as a SiO ₂ film and a SiN film provided so as to cover the first TFT element 4, and an interlayer A metal wiring 6 is formed through the insulating film 5 and electrically connected to the first TFT element 4. Further, the metal wiring 6 is further extended on the interlayer insulating film 5 to constitute a first electrode 7 of the organic EL display element 11 and a wiring terminal 25 provided in the terminal region 26. An insulating film (or bank) 9 that partitions each pixel (region) 20 is formed on the interlayer insulating film 5. Examples of the material for forming the insulating film 9 include insulating resin materials such as photosensitive polyimide resin, acrylic resin, methallyl resin, or novolac resin. The thickness of the interlayer insulating film 5 can be set to 0.5 to 1 μm, for example. The thickness of the insulating film 9 can be set to 3 to 5 μm, for example.

Since the organic EL display device 1 is a bottom emission type in which light emission is extracted from the first electrode 7 side, the first electrode 7 has a high work such as ITO or SnO ₂ from the viewpoint of improving the light extraction efficiency. It is preferable to use a thin film of a material having a function and high light transmittance.

Further, as shown in FIGS. 2 and 3, an organic EL layer 8 is formed on the first electrode 7. The organic EL layer 8 includes a hole transport layer and a light emitting layer. The hole transport layer is not limited as long as the hole injection efficiency is good. As the material for the hole transport layer, for example, organic materials such as a triphenylamine inducer, a polyparaphenylene vinylene (PPV) inducer, and a polyfluorene derivative can be used.

The light emitting layer is not particularly limited, and for example, 8-hydroxyquinolol inducer, thiazole inducer, benzoxazole inducer and the like can be used. Moreover, you may combine 2 or more types among these materials, and may combine additives, such as dopant material.

Although the organic EL layer 8 has a two-layer structure of a hole transport layer and a light emitting layer, it is not limited to this configuration. That is, the organic EL layer 8 may have a single layer structure composed of only the light emitting layer. In addition, the organic EL layer 8 may be configured by one or more of a hole transport layer, a hole injection layer, an electron injection layer, and an electron transport layer, and a light emitting layer.

Further, the second electrode 10 is formed on the organic EL layer 8 and the insulating film 9. The second electrode 10 has a function of injecting electrons into the organic EL layer 8. Although the 2nd electrode 10 can be comprised by thin films, such as Mg, Li, Ca, Ag, Al, In, Ce, or Cu, for example, it is not limited to this at all.

The organic EL display element 11 is formed by the first electrode 7, the organic EL layer 8 having a light emitting layer and the second electrode 10 formed on the organic EL layer 8 while being formed on the first electrode 7. It is configured.

In the organic EL display device 1, the first electrode 7 has a function of injecting holes into the organic EL layer 8, and the second electrode 10 has a function of injecting electrons into the organic EL layer 8. The holes and electrons injected from the first electrode 7 and the second electrode 10 are recombined in the organic EL layer 8, whereby the organic EL layer 8 emits light. In addition, the base layer 2 and the first electrode 7 are configured to be light transmissive, and the second electrode 10 is configured to be light reflective. Light emission is transmitted through the first electrode 7 and the base layer 2 and extracted from the organic EL layer 8. (Bottom emission method).

As shown in FIG. 2, the integrated circuit chip 27 is provided with a connection terminal 27a. By connecting the wiring terminal 25 and the terminal 27a, the integrated circuit chip 27 is connected via the wiring terminal 25. The integrated circuit chip 27 is mounted so as to be connected to the first TFT 4.

The first TFT element 4 is a TFT using amorphous silicon, for example, and uses amorphous silicon as a channel. Since the first TFT element 4 is amorphous, the carrier mobility of electrons and the like is lower than that of a TFT element using polysilicon, but the display has a large screen (that is, a large display area). An apparatus can be provided.

Further, as shown in FIG. 3, a second TFT element 41 that is an active element of the driver section 23 is formed in the drive circuit region 24. In addition, a metal wiring 43 that penetrates the interlayer insulating film 5 and is electrically connected to the second TFT element 41 is formed in the driver portion 23, and the first TFT is connected via the metal wiring 43. The element 4 and the second TFT element 41 and the adjacent second TFT elements 41 are connected.

Here, in the organic EL display device 1 according to the present embodiment, as shown in FIGS. 1 to 3, the display area 22 is provided with a deformation preventing member 28 for preventing the display area 22 from being deformed. There is a feature.

With such a configuration, the rigidity of the display region 22 in the organic EL display device 1 can be improved, so that it is possible to effectively prevent the display region 22 from being deformed such as warpage or swell. Become.

Further, as shown in FIG. 1, in the frame region 22 provided around the display region 21, the deformation preventing member 28 is not provided and the film-like flexible plastic substrate 2 is provided. It is the composition which is. Therefore, as shown in FIG. 2, it is possible to bend the terminal region 26 defined in the frame region 22 in the direction of the arrow X in the figure with the peripheral edge 21a of the display region 21 as a boundary. Similarly, as shown in FIG. 3, it is possible to bend the drive circuit region 24 defined in the frame region 22 in the direction of the arrow Y in the figure with the peripheral edge 21a of the display region 21 as a boundary. That is, since the frame area 22 provided around the display area 21 can be bent, the frame area 22 around the display area 21 can be eliminated in a plan view as shown in FIG. .

In addition, unlike the above-described conventional technology, it is not necessary to increase the thickness of the plastic substrate, so that the organic EL display device 1 can be reduced in thickness and weight.

As shown in FIGS. 2 and 3, the deformation preventing member 28 is laminated in the display region 21 via an adhesive layer 29 provided on the organic EL display element 11 (that is, the second electrode 10). It is the composition which becomes. The deformation preventing member 28 may be configured such that the entire surface thereof is provided via the adhesive layer 29, or a part of the deformation preventing member 28 may be provided via the adhesive layer 29.

The material for forming the deformation preventing member 28 is not particularly limited as long as it can prevent deformation of the display region 22. For example, glass, hard plastic, metal, or the like can be used. . Examples of the glass that can be used include alkali-free glass and alkali glass. In addition, as the hard plastic, for example, polyvinyl chloride, polypropylene or the like can be used, and as the metal, for example, SUS, aluminum or the like can be used. The thickness of the deformation preventing member 28 is preferably 0.05 to 0.3 mm. This is because when the thickness is less than 0.05 mm, the rigidity of the display region may not be sufficiently improved. When the thickness is greater than 0.3 mm, the thickness of the entire organic EL display device 1 is large. This is because there is a case.

Moreover, it does not specifically limit as an adhesive agent which comprises the adhesive bond layer 29, As this adhesive agent, various resin adhesives, such as an epoxy resin type, a butyral resin type, an acrylic resin type, are mentioned, for example. It is done.

Next, a method for manufacturing the organic EL display device 1 according to the embodiment of the present invention will be described. The manufacturing method shown below is merely an example, and the organic EL display device 1 according to the present invention is not limited to the one manufactured by the method shown below. 5 to 14 are cross-sectional views for explaining a method for manufacturing an organic EL display device according to an embodiment of the present invention. More specifically, FIG. 6, FIG. 8, FIG. 10, FIG. 11, and FIG. 13 are cross-sectional views for explaining a method for manufacturing an organic EL display device in the AA cross-sectional direction of FIG. 7, 9, 12, and 14 are cross-sectional views for explaining a method of manufacturing the organic EL display device in the BB cross-sectional direction of FIG.

First, as shown in FIG. 5, for example, a glass substrate 50 having a thickness of about 0.7 mm is prepared as a support substrate.

Next, as shown in FIG. 5, for example, a sacrificial film formed on a glass substrate 50 with a resin material having a heat resistant temperature (or glass transition temperature) of 400 ° C. or higher and a thermal expansion coefficient of 10 ppm / ° C. or lower. 51 is formed with a thickness of about 0.1 to 1 μm, for example. As the resin material of the sacrificial film 51 that satisfies such conditions, for example, a polyimide resin can be used. The sacrificial film 51 is for favorably peeling the glass substrate 50.

Next, in the case of a transmissive display element, a film-like substrate layer 2 made of a transparent resin film is formed on the sacrificial film 51 with a thickness of about 5 μm, for example. As the resin material for forming the base layer 2, polyimide resin, fluorene epoxy resin, and fluorine resin can be used. The base layer 2 is formed by applying a resin on the surface of the sacrificial film 51. In the case of a reflective display element or a top emission self-luminous display element, the sacrificial film is omitted by forming the base layer 2 using the same resin material as that for forming the sacrificial film 51. It is good also as a structure.

Subsequently, as shown in FIG. 6, a metal film, a semiconductor film, and the like are formed and patterned on the plastic substrate 2 to form the first TFT element 4 that is a switching element of the pixel 20. At this time, as shown in FIG. 7, in the driver portion 23, a metal film, a semiconductor film, or the like is formed on the plastic substrate 2, patterning is performed, and the second element which is an active element of the driver portion 23. A TFT element 41 is formed.

Next, as shown in FIGS. 6 and 7, on the plastic substrate 2 on which the first TFT element 4 and the second TFT element 41 are formed, for example, using an SiO ₂ film, an SiN film or the like, an interlayer is formed. The insulating film 5 is formed so as to have a thickness of about 1 to 2 μm.

Subsequently, as shown in FIGS. 6 and 7, a contact hole is provided from the surface of the interlayer insulating film 5 to the first TFT element 4 and is electrically connected to the first TFT element 4 by a transparent conductive material such as ITO. The metal wiring 6 to be formed is formed, and further, for example, the first electrode 7 and the wiring terminal 25 having a thickness of about 150 nm are formed by patterning or the like. Further, as shown in FIG. 7, a contact hole is provided from the surface of the interlayer insulating film 5 to the second TFT element 41, and the first TFT element 4 and the second TFT element 4 are electrically connected with a transparent conductive material such as ITO. The metal wiring 43 to be connected is formed.

Next, as shown in FIGS. 6 and 7, after an insulating film 9 having a thickness of, for example, about 3 μm is formed on the interlayer insulating film 5, a portion corresponding to the first electrode 7 is removed by etching.

Next, as shown in FIGS. 6 and 7, an organic EL layer 8 is provided by forming a hole transport layer and a light emitting layer on the first electrode 7. As the hole transport layer, first, a hole transport material paint in which an organic polymer material that is a hole transport material is dissolved or dispersed in a solvent is supplied onto the exposed first electrode 7 by, for example, an inkjet method or the like. . Thereafter, a hole transport layer is formed by performing a baking treatment. Next, as the light-emitting layer, an organic light-emitting material paint in which an organic polymer material that is a light-emitting material is dissolved or dispersed in a solvent is supplied so as to cover the hole transport layer by, for example, an inkjet method. Then, a light emitting layer is formed by performing a baking process.

Subsequently, as shown in FIG. 6 and FIG. 7, the second film is formed on the insulating film 9 and the organic EL layer 8 using Mg, Li, Ca, Ag, Al, In, Ce, Cu, or the like by sputtering or the like. The electrode 10 is formed. The thickness of the second electrode 10 is about 150 nm, for example. Thus, an organic EL formed by the first electrode 7, the organic EL layer 8 having a light emitting layer and the second electrode 10 formed on the organic EL layer 8 while being formed on the first electrode 7. Element 11 is formed.

Next, as shown in FIGS. 8 and 9, in the display region 21, for example, an epoxy resin-based adhesive layer 29 is formed on the second electrode 10, and on the adhesive layer 29, for example, A deformation preventing member 28 made of glass is provided.

Next, as shown in FIG. 10, in the terminal region 26, the integrated circuit chip 27 is mounted by connecting the terminal 27 a of the integrated circuit chip 27 and the wiring terminal 25, and the integrated circuit chip 27 and the first TFT 4. And connect.

Next, as shown in FIGS. 11 and 12, the glass substrate 50 is peeled off by irradiating laser light (arrows in FIGS. 11 and 12) from the glass substrate 50 side.

Here, the removal of the glass substrate 50 may not be peeling by laser light irradiation. For example, the glass substrate 50 may be removed using a polishing and etching apparatus.

Next, as shown in FIGS. 13 and 14, the sacrificial film 51 exposed by removing the glass substrate 50 is removed by plasma etching. Here, the removal of the sacrificial film 51 is not limited to plasma etching, and may be performed by, for example, microwave plasma etching. In the case of a reflective display element or a top emission self-luminous display element, the sacrificial film 51 does not need to be etched.

The organic EL display device 1 shown in FIGS. 1 to 3 is manufactured by the above method.

According to the present embodiment described above, the following effects can be obtained.

(1) In this embodiment, the display area 21 of the organic EL display device 1 is provided with a deformation preventing member 28 for preventing the display area 21 from being deformed. Accordingly, since the rigidity of the display area 21 is improved, it is possible to effectively prevent the display area 21 from being deformed such as warping or swell.

(2) In the frame region 22 provided around the display region 21, the plastic substrate 2 having flexibility is provided, but the deformation preventing member 28 is not provided. Therefore, since the frame area 22 provided around the display area 21 can be bent, the frame area 22 around the display area 21 can be eliminated in a plan view. Accordingly, it is possible to provide the organic EL display device 1 having a narrow frame with almost no frame on the display surface.

(3) Further, unlike the above-described conventional technique, it is not necessary to increase the thickness of the plastic substrate, and thus the display device 1 can be reduced in thickness and weight.

(4) In this embodiment, the thickness of the deformation preventing member 28 is set to 0.05 to 0.3 mm. Accordingly, it is possible to prevent the disadvantage that the thickness of the entire organic EL display device 1 is increased in a state where the rigidity of the display region 21 is sufficiently secured, and to reduce the thickness and weight of the organic EL display device 1. become.

(5) In the present embodiment, the deformation preventing member 28 is formed of one type selected from the group consisting of glass, hard plastic, and metal. Therefore, the deformation preventing member 28 can be formed from an inexpensive and versatile material.

(6) In the present embodiment, the adhesive layer 29 is provided on the organic EL display element 11, and the deformation preventing member 28 is provided via the adhesive layer 29. Therefore, the deformation preventing member 28 can be provided in the display area 21 with a simple configuration.

Note that the above embodiment may be modified as follows.

From the viewpoint of insulating and protecting the mounted integrated circuit chip 27 and preventing the integrated circuit chip 27 from being peeled off, the integrated circuit chip 27 is sealed with a sealing member (not shown) formed of epoxy resin or the like. It is good also as a structure.

Although the present embodiment and the display device related to organic EL (organic electro luminescence) have been shown, the display device includes LCD (liquid crystal display), electrophoresis (electrophoretic), PD (plasma display). Display), PALC (plasma addressed liquid crystal display), inorganic EL (inorganic electroluminescence), FED (field emission display), or SED (surface-conduction electron-emitter display) A display device related to a display) or the like may be used.

As described above, the present invention is useful for display devices such as organic EL display devices.

DESCRIPTION OF SYMBOLS 1 Organic EL display device 2 Plastic substrate 11 Organic EL display element 21 Display area 22 Frame area 28 Deformation prevention member 29 Adhesive layer

Claims (5)

A display device comprising a flexible plastic substrate and a display element formed on the plastic substrate, and having a display region and a frame region provided around the display region,
A display device, wherein a deformation preventing member for preventing deformation of the display area is provided in the display area. The display device according to claim 1, wherein the thickness of the deformation preventing member is 0.05 to 0.3 mm. 3. The display device according to claim 1, wherein the deformation preventing member is formed of one selected from the group consisting of glass, hard plastic, and metal. The adhesive layer according to any one of claims 1 to 3, wherein an adhesive layer is provided on the display element, and the deformation preventing member is provided via the adhesive layer. Display device. The display device according to any one of claims 1 to 4, wherein the display element is an organic EL display element.

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