JP2003337549A - Substrate for flat panel display, display device, organic electroluminescence element, and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a flat panel display (FDP) which is light in weight, is hardly crackable, and has performance to sufficiently prevent the permeation of substances to active substances, such as moisture and oxygen, and can be bent, a display device, an organic electroluminescence element, and a liquid crystal display element. <P>SOLUTION: The substrate for the FDP arranged with an adhesive layer or tacky adhesive layer between a glass plate of 10 to 300 μm in thickness and a resin film is used on the outside surface side of a display element for the FDP. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display (FPD) substrate used for a liquid crystal display element, an organic electroluminescence (EL) display element, and the like.

[0002]

2. Description of the Related Art In recent years, with the progress of rapid technological development in the field of information and communications, great expectations are placed on FPDs that replace CRTs. For example, a liquid crystal display (LC
D) is widely used in notebook PCs and mobile phones because of its thinness, low driving voltage, and low power consumption.
It is rapidly spreading as a desktop monitor. In addition, organic EL display devices have been actively researched because they are excellent in high-speed response, visibility, and brightness, and have been put into practical use.

In many of these FPDs, a display element is manufactured on a glass substrate. The glass substrate has features such as chemical resistance and plasma resistance that can withstand the process of forming an active matrix such as an amorphous silicon TFT or a low temperature polysilicon TFT.

For a liquid crystal display device, the flatness of a glass plate is used to bond two glass substrates together via a spacer, so that a uniform cell gap required for the liquid crystal display device can be easily obtained. It also has the excellent feature that it can be obtained.

On the other hand, in an organic EL device, a metal having a low work function such as an alkali metal, an alkaline earth metal, or a rare earth metal, an alloy of these metals, a compound of these metals, etc., for efficiently injecting electrons as a cathode material. Highly chemically active materials are commonly used. Further, layers containing various organic compounds including a light emitting layer are provided between the electrodes.

[0006] These electrode materials and organic compounds existing between the electrode layers are likely to be denatured by oxygen and moisture in the atmosphere, and delamination is likely to occur due to degeneration of these materials. Therefore, a non-light emitting portion called a dark spot is likely to occur in the light emitting portion of the organic EL element. Therefore, in order to improve the stability and reliability of the organic EL element, means for protecting the inside of the organic EL element from active substances such as moisture and oxygen in the atmosphere and preventing deterioration of the element are important.

To solve this problem, the glass substrate has a sufficient barrier property. Therefore, an organic EL device having a light emitting layer formed on a glass substrate has been put into practical use.

However, the conventional glass substrate F
PD has the drawbacks of being heavy, fragile, and inflexible, and in order to solve this, an organic EL element using a plastic substrate equipped with measures against active substances such as moisture and oxygen in the atmosphere. Is proposed.

In this case, as a measure against active substances such as moisture and oxygen in the atmosphere, a substance permeation preventive film is often laminated on a plastic substrate to prevent permeation of these substances. Well-known are inorganic thin films such as silicon oxide films, silicon nitride films, and alumina, and organic thin films, and laminated films of these inorganic thin films. The same applies to the liquid crystal display element.

[0010]

However, in order to obtain sufficient substance permeation prevention performance by coating an inorganic film or an organic film on a plastic substrate, it is necessary to increase the thickness of the inorganic film or It is necessary to stack with an organic film.

On the other hand, to form an inorganic thin film having a thickness of 1 μm to several μm on a substrate having a sufficient area for display by a known method such as sputtering, chemical vapor deposition (CVD) or vapor deposition. It takes 10 minutes to several tens of minutes or more, which is a heavy manufacturing burden.

[0012] In addition, in order to obtain sufficient substance permeation preventive performance by the method of alternately laminating inorganic thin films and organic thin films, it is often necessary to have multiple layers. This is to prevent defects such as pinholes and cracks existing in the inorganic thin film and the organic thin film by stacking layers.
In this case, the apparatus cost is often enormous because many film forming chambers are required. Further, when a thin film having a high refractive index such as a nitride film is used, there may be a problem in that colors are different depending on the viewing direction of the display due to optical interference.

The present invention solves such problems, is lightweight, is hard to break, can be bent, and has a sufficient substance permeation-preventing performance for active substances such as moisture and oxygen.
The purpose is to provide a substrate for D.

[0014]

According to the first aspect of the present invention, an adhesive layer or an adhesive layer is arranged between a glass plate having a thickness of 10 to 300 μm and a resin film, and used in a display element for a flat panel display. In this case, at least one of the glass plate and the resin film is a flat panel display substrate used on the outer surface side of the display element.

In the second aspect, the thickness of the adhesive layer or the adhesive layer is 1
The substrate for a flat panel display according to Aspect 1, which has a thickness of 0 to 50 μm.

Aspect 3 is the substrate for a flat panel display according to Aspect 1 or 2, wherein a linear polymer is used for the resin film.

Aspect 4 is an adhesive layer or an adhesive layer and a resin film.
The coefficient of thermal expansion of each of Rum and α _S, Α_PIf
To 1.2α_S≧ α_P≧ 0.8α_SClaims 1 or 2
Or the substrate for a flat panel display described in 3.
It

Aspect 5 is the flat panel display substrate according to Aspect 1, 2, 3 or 4, wherein the deviation of the thickness of the substrate is 10 μm or less.

Aspect 6 is the above Aspect 1, 2, 3, 4 or 5 in which, when the substrate is bent, the radius of curvature can be bent to L / π with respect to the length L of at least one side along the bending direction. It is the substrate for a flat panel display described.

Aspect 7 is the substrate for flat display according to any one of Aspects 1 to 6, which has a substrate area of 20000 mm ² or more and is capable of forming four or more substrates in a multifaceted manner.

Aspect 8 is an instrument display device for an automobile provided with the flat panel display substrate according to any one of Aspects 1 to 7.

Aspect 9 is an organic electroluminescence device having the flat panel display substrate according to any one of Aspects 1 to 7 on at least one substrate.

A tenth aspect is a liquid crystal display device in which at least one substrate is provided with the flat panel display substrate according to any one of the first to seventh aspects.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. These figures and description are merely illustrative of the invention and do not limit the scope of the invention. It goes without saying that other embodiments can be included in the scope of the present invention as long as they match the spirit of the present invention. In the drawings, the same reference numerals are used for the same parts.

A feature of the present invention is that a thin glass plate and a resin film are laminated. Due to this lamination, the FPD substrate and the organic EL element and the liquid crystal display element using the FPD substrate are light in weight, difficult to break, and have sufficient substance permeation-preventing performance for active substances such as moisture and oxygen. become. Further bending may also be possible. Further, when manufacturing the FPD substrate, a special step of forming a substance permeation preventive film is unnecessary. In addition, the thin glass is T
It is known to be used for substrates of FT display devices,
Japanese Patent Application Laid-Open No. 60-244924 describes the lamination of a thin glass plate and a resin film, but it is not intended to realize the substance permeation prevention performance and the flexibility.

Since the glass substrate is excellent in the substance permeation preventing performance, it is sufficient that it has a thickness of 10 μm. On the other hand, the thickness of the glass substrate is 40 in the case of a typical organic EL device.
Since the thickness is about 0 μm, the effect of weight reduction becomes clear when the thickness is 300 μm or less. Further, if it is 200 μm or less, the flexibility is clearly exhibited.

Considering the above, a glass substrate having a thickness of 10 to 300 μm is suitable for the flexible laminated substrate.
A preferable thickness is 0 to 200 μm. 50 to 1
The range of 00 μm is more preferable because the weight reduction effect and the flexibility are large.

If a glass plate in this range is used, a flat panel display substrate having a small radius of curvature can be realized. Specifically, it has been found that when the substrate is bent, the curvature radius can be bent to L / π with respect to the length L of at least one side along the bending direction. Radius of curvature is L /
More preferably, it is between π and 10 L / π.

In any case, the substance permeation preventing performance is sufficient, and by laminating it with the resin film,
It also has sufficient resistance to mechanical damage and is less likely to break.

The effects of imparting flexibility are as follows. First, the glass substrate can be rolled and stored, moved, and used, which can contribute to the rationalization of the production process.

Next, when a curved display element is manufactured, the glass substrate can be arranged along a desired shape, and it is not necessary to give the glass substrate a curved shape in advance.

Further, even if the manufactured display element has a flat shape, it is possible to easily manufacture a display device bent into a curved surface.

Further, even if the display device incorporating the manufactured display element has a flat shape, it can be bent into a curved surface. That is, a flexible FPD can be realized.

As the material of the glass plate according to the present invention, any known material can be used as long as it does not violate the gist of the present invention. Soda glass can be used for the simple matrix liquid crystal display element and the organic EL element. In the case of active elements such as TFT, non-alkali glass can be used.

It should be noted that the glass according to the present invention has a plate-like shape laminated in advance. Therefore, the glass layer is not formed on the spot by film formation or the like. By using a plate-shaped product in advance, it becomes easy to secure excellent surface properties without defects.

As the resin film according to the present invention, any resin film can be used as long as it does not violate the gist of the present invention. In some cases, it may be transparent as long as it does not impair the translucency when visually observed. Generally, linear polymers such as polyester, polycarbonate, polyether sulfone, polyolefin and polyvinyl alcohol are preferable because of their excellent quality.

In the case of laminating with a glass plate, it is preferable to attach a resin film to the glass plate, but a method of coating or casting a resin on the glass plate to form a film is also possible in some cases.

Since the role of the resin film is mainly to impart mechanical strength, even if it can be formed into a film,
Generally, it is better not to use a material that does not contribute to imparting mechanical strength. For example, although a film shape can be obtained by applying a thermosetting resin that forms a crosslinked structure and then curing it, it is generally not preferable because the mechanical strength is low. What kind of resin is suitable can be easily determined by laminating it on a glass plate and measuring its breaking strength and the like.

When a resin film is used for lamination, if it is uniaxially or biaxially stretched and oriented, the isotropic refractive index is impaired, but the Young's modulus and strength are increased. Therefore,
The invention also contemplates the use of such films.

Generally, even when a linear polymer is used, if the resin film is too thick, the flexibility will be impaired, so 500 μm or less is preferable. The lower limit is not particularly limited, but it is 10 in consideration of handling in the device manufacturing process.
It is preferably 0 μm or more.

The laminated structure may be a two-layer structure of glass plate / resin film, or may be a three-layer structure of glass plate / resin film / glass plate with both surfaces being glass plate surfaces, or resin film / Both surfaces may be resin film surfaces as a three-layer structure of glass plate / resin film. Incidentally, as the surface contacting with the device side surface, that is, the surface side where the wiring and the TFT element are formed, in general, either a glass plate surface or a resin film surface may be used, but ITO (indium oxide-oxide) The glass plate surface is often preferable in consideration of the plasma atmosphere and the seal adhesiveness in the sputtering step when forming the tin electrode or the metal wiring.

In this substrate, at least one of a glass plate and a resin film is used on the outer surface side of the display element. As a result, an organic EL element using this FPD substrate,
The liquid crystal display device and the like are lightweight, are not easily broken, and have sufficient performance of preventing permeation of active substances such as water and oxygen.

In the case of the three-layer structure, it is preferable that the structure is axisymmetric with respect to the center line of the cross section in the thickness direction of the substrate, because it is possible to prevent warpage due to the characteristic difference of each material with respect to temperature change. A protective film or an anti-glare layer may be further disposed on the surface of the outermost layer of the two-layer or three-layer structure.

The thickness deviation of the composite type substrate in which a thin glass substrate and a resin film are laminated has a deviation of 10 μm.
It is preferably m or less. This is because uniform display is facilitated, and it is particularly useful for matching the optical characteristics of the entire screen when a large display is performed. Here, the thickness variation deviation means a difference between the upper limit and the lower limit of the variation in thickness.

As a laminating method, a method of adhering with an adhesive or a method of adhering with an adhesive can be used. As the adhesive and the pressure-sensitive adhesive, a thermosetting type and an ultraviolet curing type which can be cured within the range of the glass transition point (Tg) of the resin or lower can be used. A well-known die coater or dispenser can be used to apply the adhesive or the pressure-sensitive adhesive. Considering the difference in the coefficient of thermal expansion between the glass plate and the resin film, and the fact that the display element is often used after being bent, the adhesive layer itself has a predetermined length so that the whole substrate can be bent after the formation of the substrate. It is preferable to have flexibility. For this purpose, it is preferable to use an organic adhesive material capable of exhibiting flexibility after adhesion. Further, considering the influence of thermal expansion, when the respective thermal expansion coefficients of the adhesive layer or the adhesive layer and the resin film are α _S and α _P , 1.2 α _S ≧ α _P ≧
It is preferably 0.8α _S. Instead of bonding a glass plate having a predetermined plate thickness from the beginning, it is possible to bond the glass substrate and the resin film and then polish the surface of the glass substrate to a predetermined plate thickness. The thickness of the adhesive layer or the tacky layer is preferably 10 to 50 μm. If it is thinner than this range, it may be difficult to obtain sufficient adhesiveness and tackiness, and if it exceeds this range, the transparency of the display element and the parallelism between the glass substrate and the resin film may be impaired.

Adhesive materials that can be used include a mixture of polyurethane, polyvinyl chloride, polyvinyl acetate, vinyl alcohol and the like. Epoxy resin, polyvinyl butyral, polymethacrylic acid ester, cyclized rubber, ethyl cellulose, vinyl copolymer and the like are available, and they have good adhesiveness to a glass substrate. Further, as the characteristic of the adhesive material or the adhesive material, it is particularly preferable to use an optically transparent material in the visible wavelength range.

The state of the above-mentioned lamination will be exemplified below. Figure 1
FIG. 3 is a cross-sectional model view of the FDP substrate having the glass plate / resin film configuration according to the first embodiment of the present invention. In FIG. 1, an FDP substrate 1 is a glass plate 2 and a glass plate 20 having a thickness of 50 μm.
A resin film 3 having a thickness of 0 μm is bonded with an adhesive 4. Place a thin glass substrate on the specified substrate,
The display layer may be formed, the glass substrate and the substrate may be separated thereafter, and the resin film layer may be adhered or adhered.

FIG. 2 is a cross-sectional model view of a glass plate / resin film / glass plate FDP substrate according to the second embodiment of the present invention. In FIG. 2, the FDP substrate 1 is
Two layers of a glass plate 2 of 50 μm and a resin film 3 of 200 μm are bonded with an adhesive 4.

The flat FDP substrate shown in FIGS. 1 and 2 is bent by appropriately selecting bending conditions such as the resin film, the thickness of the glass plate, the type of adhesive and the heating and pressing conditions. It may be bendable only during operation or permanently bendable. This state is illustrated in FIG. FIG. 3 is a cross-sectional model diagram of the FDP substrate 1 showing a state in which the FDP substrate 1 having the same configuration as that of FIG. 2 is curved.

The following method can be exemplified as a method of manufacturing a substrate for FDP which is curved. That is, the glass plate and the resin film are respectively bent, an adhesive material is supplied between the both, and pressure is applied from the outer surface side of the substrate to press-bond the both,
Bonding is performed by applying pressure from the outer surface side of the substrates so that the adhesive layer has a predetermined thickness. At this time, a roller can also be used. For continuous formation, it is preferable to use a liquid adhesive material. Alternatively, a layered adhesive prepared in advance may be sandwiched between the glass substrate and the resin film. It is preferable to form the adhesive material under a temperature condition where the adhesive material does not solidify.

An organic EL element can be produced by using this laminated substrate. ITO is sputtered on this substrate,
Patterning is performed using a normal photolithography method. A hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer, and a cathode are appropriately subjected to mask vapor deposition in this order to form an organic EL light emitting portion. Further, a protective film having a substance permeation preventing property, for example, a moisture-proof protective film may be formed by using a known film forming method such as plasma CVD. An organic EL element can be obtained by applying an adhesive or a pressure-sensitive adhesive on the organic EL element substrate manufactured in this way, and then laminating another laminated substrate as a sealing substrate. At this time,
In some cases, an adhesive or pressure-sensitive adhesive is applied so as to surround the organic EL light-emitting portion, and a space is provided between the organic EL element substrate and the sealing substrate to bond the organic EL element substrate and the organic EL light-emitting portion. In some cases, an adhesive or a pressure-sensitive adhesive is applied, and the organic EL element substrate and the sealing substrate are bonded together so as to be molded without providing a space. Further, when only a protective film having a substance permeation preventive property, for example, a moisture-proof protective film has sufficient characteristics, a sealing substrate may not be provided.

In this case, any material can be used as the material of the sealing substrate to be laminated on the above, but it is lightweight, is not easily broken, and has a sufficient substance against active substances such as moisture and oxygen. It is often preferable to use the substrate according to the present invention, considering that it has anti-permeation properties and can be bent.

A TFT array device can also be formed on this laminated substrate (Technical Digest of
SID2000, p. 916). Then, an organic EL light-emitting film is applied thereto by a known inkjet method, a cathode is vapor-deposited, a protective film is formed in the same manner as above, and another laminated substrate is attached to form an organic EL element. be able to.

Similarly, after the ITO wiring or the TFT array is manufactured, the LCD device can be manufactured through the well-known liquid crystal device manufacturing process similarly to the plastic LCD.

As an example of the structure of the organic EL element,
FIG. 4 is a cross-sectional model view of an organic EL element in which the organic EL light emitting unit 5 is formed on the FDP substrate 1 of FIG. 1 and is sealed with a protective resin layer 6. In this case, the organic EL light emitting unit 5
The glass plate 1 and the protective resin layer 6 are protected from the influence of moisture, oxygen and the like.

FIG. 5 is a cross-sectional model view of an organic EL element in which the FDP substrate 1 and the organic EL light emitting section 5 are housed in a metal case 7 without using a protective resin layer. In this case, the organic EL light emitting unit 5 is protected by the glass plate 1 and the metal case 7 from the influence of moisture, oxygen and the like. Although the metal case is not flexible, it can be made lighter and thinner. Instead of a metal case, a case made of glass or other material can be used.

Further, FIG. 6 shows that the organic EL light emitting portion 5 is formed on the FDP substrate 1 of FIG. 1, and this is sealed with a protective resin layer 6 which also has an adhesive function. FIG. 3 is a cross-sectional model diagram of an organic EL element in which one FDP substrate 1 is laminated. In this case, the organic EL light emitting section 5 is protected by the glass plate 1 and the protective resin layer 6 from the influence of moisture, oxygen and the like.

In FIGS. 4 to 6, the thickness of each layer does not reflect the actual state but is deformed for easy understanding. For example, in the actual example, when the thickness of the glass plate 2 is 50 μm, the thickness of the organic EL light emitting unit 5 is 1 μm or less. Therefore, in the case of FIG. 4, the protective resin layer 6 is required to have a very high substance permeation prevention function, but in the case of FIG. 6, moisture and oxygen are prevented from entering from the side portion of the protective resin layer 6. There are not many, if any, and it is often sufficient to have a certain degree of substance permeation prevention function.

Further, the flat panel display substrate according to the present invention can be used in a meter display device of an automobile. This is because the instrument display device of an automobile may have a severer environment such as humidity and shock than other applications.

As a substrate used for such a display element, it is preferable that the substrate area is 20000 mm ² or more, and four or more substrates can be formed in multiple faces.

[0061]

The FPD substrate according to the present invention and the FP
The display device, the organic EL element and the liquid crystal display element using the D substrate have a light weight, are hard to be broken, and have a sufficient substance permeation-preventing performance with respect to active substances such as moisture and oxygen. It can also be bendable. No special step of forming a substance permeation preventive film is required for manufacturing the FPD substrate.

[Brief description of drawings]

FIG. 1 is an F of a glass plate / resin film structure according to the present invention.
The cross-sectional model figure of the board | substrate for DP.

FIG. 2 is a cross-sectional model view of a glass plate / resin film / glass plate FDP substrate according to the present invention.

FIG. 3 is a transverse cross-sectional model diagram of the FDP substrate showing a curved state of the FDP substrate having the same configuration as that of FIG.

FIG. 4 is a cross-sectional model view of an organic EL element in which an organic EL light emitting unit is formed on the FDP substrate of FIG. 1 and is sealed with a protective resin layer.

FIG. 5 is a cross-sectional model view of an organic EL element in which a FDP substrate and an organic EL light emitting unit are housed in a metal case.

FIG. 6 is a cross-sectional model view of an organic EL element having a structure of an FDP substrate, an organic EL light emitting section, and an FDP substrate.

[Explanation of symbols]

1 FDP substrate 2 glass plates 3 resin film 4 adhesive 5 Organic EL light emitting unit 6 Protective resin layer 7 metal case

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H090 JA09 JA16 JB02 JB03 JB06                       JB07 JB11 JD11 JD12 JD18                       LA01                 3D044 BA01 BA03 BC04                 3K007 AB08 AB12 AB13 AB15 AB17                       BA07 CA01 CA06 DB03                 5C094 AA36 AA38 BA27 BA43 DA06                       DA12 EB01 FB01 FB02

Claims (10)

[Claims] 1. An adhesive layer or an adhesive layer is disposed between a glass plate having a thickness of 10 to 300 μm and a resin film, and at least the glass plate or the resin film is used when used for a display element for a flat panel display. One is a flat panel display substrate that is used on the outer surface of the display element. 2. The thickness of the adhesive layer or the adhesive layer is 10 to 50 μm.
The substrate for a flat panel display according to claim 1, which is m. 3. The flat panel display substrate according to claim 1, wherein a linear polymer is used for the resin film. 4. When the thermal expansion coefficients of the adhesive layer or the adhesive layer and the resin film are α _S and α _P , 1.2α
The flat panel display substrate according to claim 1, wherein _S ≧ α _P ≧ 0.8α _S. 5. The flat panel display substrate according to claim 1, wherein the deviation of the thickness of the substrate is 10 μm or less. 6. When the substrate is bent, the radius of curvature is L / π with respect to the length L of at least one side along the bending direction.
The substrate for a flat panel display according to claim 1, 2, 3, 4, or 5, which can be bent up to. 7. The substrate area is 20000 mm ² or more,
The substrate for flat display according to any one of claims 1 to 6, wherein four or more substrates can be formed in multiple planes. 8. An instrument display device for an automobile provided with the flat panel display substrate according to claim 1. 9. An organic electroluminescent device comprising the flat panel display substrate according to claim 1 on at least one substrate. 10. A liquid crystal display device comprising the flat panel display substrate according to claim 1 on at least one substrate.