WO2004029917A1

WO2004029917A1 - Display device

Info

Publication number: WO2004029917A1
Application number: PCT/JP2003/011461
Authority: WO
Inventors: Noriko Watanabe
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2002-09-27
Filing date: 2003-09-08
Publication date: 2004-04-08
Also published as: AU2003264396A1; TW200413774A; US20060254107A1; JP2004117937A; TWI248535B

Abstract

A display device comprises a display panel (1) and a frame (2) that is provided on the outer peripheral edge of the display panel. The frame (2) has a support portion (2) that supports the main face of a substrate of the display panel (1) at the peripheral edge of the display panel (1). The support portion (2) has, on its side opposed to the main face of the substrate (1), a flat portion (2a) and a first curve portion (2b) that is provided continuously from the flat portion (2a). The main face of the substrate (1) is directly or indirectly fixed to the flat portion (2a). In a state where the display panel is free from external force, vacant space is formed between the main face of the substrate (1) and the curve portion (2b).

Description

Detail

Technical field

The present invention relates to a display device, and more particularly, to a display panel mounting structure. Background art

In recent years, various types of flat panel displays have been used as display devices in place of CRTs. Among flat panel displays, liquid crystal display devices are widely used as display devices for mobile applications such as mobile phones and PDAs, taking advantage of their features of thinness, light weight, and low power consumption.

In particular, for mopile applications, further reduction in thickness and weight of display devices is desired, and glass substrates, which account for most of the thickness and weight of display devices, are being made thinner. However, thinner glass substrates are much more prone to breakage, and the use of plastic substrates instead of glass substrates is being studied.

Since plastic substrates are not easily broken even if they are thin, flexible display devices such as sheet displays (or film displays) and wearable displays can be realized.

In general, plastic materials are inherently higher in elasticity (larger breaking elongation) than glass, and are less likely to break. However, the basics of the display device When used as a plate material, plastic may not be used alone. For example, in the case of a liquid crystal display device, in the case of a simple matrix type, there is no problem because only one layer of inorganic film is formed as a pixel electrode, but in the case of an active matrix type, a plurality of inorganic materials are formed at various temperatures. Since films must be deposited and these inorganic films must be accurately patterned, it is essential to reduce the coefficient of thermal expansion of the substrate. By combining glass fillers and fibers with plastic, a substrate with a reduced coefficient of thermal expansion while maintaining transparency (hereinafter referred to as “composite plastic substrate”) has been developed. Composite plastic substrates have properties that are intermediate between those of glass and plastic, and may be damaged in situations where local stresses are high. For example, this is the case where the corner of a hard object hits the substrate surface strongly. However, except under such severe conditions, it has been confirmed that the composite plastic substrate has high resistance to external forces and impacts, and is not damaged by external forces and impacts generated under normal use conditions of the display device. ing.

However, when a liquid crystal display device using a composite plastic substrate is used as a mopile display, damage may occur even with external force or impact that is not a problem with the substrate alone. Also, when used as a flexible display, it is expected that a larger external force will be applied than in the conventional use conditions.

We examined the causes of damage to the composite plastic substrate when assembled as a liquid crystal display device. However, it was found that it greatly affected the susceptibility of the composite plastic substrate to cracking.

It is known that the mounting structure affects the fragility of glass substrates, and various mounting structures have been proposed to prevent breakage.

For example, Japanese Utility Model Laid-Open No. 61-124016 discloses that a resin reinforcement 有する having a thickness of at least 0.4 times the total thickness of the liquid crystal panel is provided on the entire surface of one side of the liquid crystal panel with an adhesive. Or they propose a structure joined by double-sided tape. In this structure, since the reinforcing plate is provided on the entire surface including the display area of the liquid crystal panel, the light use efficiency is undesirably reduced. If the rigidity of the reinforcing plate is too high, the flexibility of the liquid crystal panel is impaired, and if the rigidity of the reinforcing plate is too low, the effect of suppressing breakage is reduced. In a configuration in which a liquid crystal panel is supported by using a frame having an opening corresponding to a display area of the liquid crystal panel, Japanese Patent Application Laid-Open No. H5-165013 discloses that a liquid crystal is provided via an adhesive layer made of an elastic material. It discloses a configuration in which a panel is fixed to an exterior case. Also, in Japanese Patent Application Laid-Open No. H11-151578, an outer peripheral end face of a liquid crystal panel is inserted and fixed in a Y-shaped fixing frame made of a flexible material, and the fixing frame is fixed to the frame. A disclosed configuration is disclosed.

However, as a result of the study by the present inventor, it has been found that Japanese Patent Application Laid-Open

With the configurations described in Japanese Patent Publication No. 3 and Japanese Patent Application Laid-Open No. H11-151578, the glass substrate can be effectively prevented from being damaged. The composite plastic substrate cannot be sufficiently prevented from being damaged. Gawakatsu. Specifically, as a result of various investigations, in the case of liquid crystal panels using composite plastic substrates, in most cases, the liquid crystal panel is directly mounted on the frame on the observer's side or on the periphery of the side opposite to the observer. In the fixed configuration, it was found that cracks occurred at the part where the liquid crystal panel was in direct contact with the frame (called the support part). This is considered for the following reasons.

Glass substrates have a smaller breaking strain than plastic substrates and can be broken by relatively weak external force or impact. Can be effectively prevented. On the other hand, it is considered that it is difficult for a composite plastic substrate with relatively large breaking strain to absorb an external force or impact that generates enough distortion to cause the composite plastic substrate to be damaged by the elastic body.

With reference to FIGS. 5 (a) to 5 (c), the mechanism of the occurrence of breakage in a configuration in which the liquid crystal display panel 1 using a composite plastic substrate is fixed to an elastic frame 12 will be described. The frame 12 having elasticity schematically shows, for example, a frame including an adhesive layer made of an elastic material described in Japanese Patent Application Laid-Open No. 5-16513. Need not be.

As shown in FIG. 5 (a), a liquid crystal display panel 1 using a composite plastic substrate is fixed to an elastic frame 12 in a state where no external force is applied.

As shown by an arrow in FIG. 5 (b), when an external force is applied to the liquid crystal panel 1, the liquid crystal panel 1 is deformed. Breaking strain of composite plastic substrate is relative Since it is relatively large, it does not break even if it deforms larger than the glass substrate. Taking advantage of this feature, a flexible display is realized.

At this time, the liquid crystal panel 1 is deformed, and at the same time, the elastic frame 12 is also deformed, and acts to suppress concentration of stress on the liquid crystal panel 1 at the corners of the elastic frame 12.

However, when the amount of deformation of the liquid crystal panel 1 increases, the deformation of the elastic frame 12 cannot catch up as shown in FIG. 5 (c), and stress concentrates on the liquid crystal panel 1 at the corners of the flexible frame 12. And damage occurs.

The frequency of occurrence of this damage does not depend much on whether or not the liquid crystal panel 1 is bonded to the support of the frame # 2.

As described above, the elastic material (soft material) disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 5-16513 and Japanese Patent Application Laid-Open No. 11-15781 is used for the liquid crystal panel and the frame. The configuration interposed therebetween has little effect of suppressing the damage of the liquid crystal panel which is relatively large and deformed.

On the other hand, Japanese Patent Application Laid-Open No. 2000-200506 discloses a plurality of optical sheets provided on a surface of a liquid crystal panel opposite to an observer side (referred to as a “lower side”). It discloses a configuration in which a light guide plate and a plurality of optical sheets are incorporated into a frame integrally with a liquid crystal panel, in which the inside of a frame portion in contact with the lowermost sheet is chamfered in an arc shape. This configuration is for preventing the lens groove surface of the light guide plate from being damaged, and does not disclose a configuration for suppressing damage to the liquid crystal panel. Although the problems of the prior art have been described using a liquid crystal display device as an example, the above problems are not limited to the liquid crystal display device, and other display devices, particularly display panels used for flexible displays (for example, organic EL display panels and electric devices). (Electrophoretic display panel). Disclosure of the invention

The present invention has been made in view of the above points, and a main object of the present invention is to provide a display device in which the display panel is hardly damaged when an external force or the like is applied to the front panel.

A display device according to the present invention includes: a display panel having a substrate; and a frame having a supporting portion that supports the display panel on a main surface of the substrate at a peripheral portion of the display panel, wherein the supporting portion includes the substrate. A flat portion, and a first curved portion provided continuously with the flat portion, the main surface of the substrate being directly or indirectly connected to the flat portion. In a state in which the substrate is fixed and no external force is applied to the substrate, a gap is formed between the main surface of the substrate and the first curved portion, whereby the object is achieved. Is achieved.

In a preferred embodiment, the support section has a second curved section facing the first curved section.

In a preferred embodiment, the main surface of the substrate is fixed to the flat portion via an adhesive layer.

In a preferred embodiment, a reinforcing plate is further provided between the main surface of the substrate and the flat portion of the support. In a preferred embodiment, the reinforcing plate is fixed to the flat portion via an adhesive layer.

It is preferable that the support part is formed of an elastic body.

When the substrate is a plastic substrate, the effects of the present invention are remarkably obtained. BRIEF DESCRIPTION OF THE FIGURES

1A to 1C are cross-sectional views schematically showing a configuration of a display device according to an embodiment of the present invention.

2 (a) and 2 (b) are cross-sectional views schematically showing a configuration of another display device according to the embodiment of the present invention.

FIGS. 3A and 3B are cross-sectional views schematically showing a configuration of another display device according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a configuration of another display device according to the embodiment of the present invention.

FIGS. 5A to 5C are schematic cross-sectional views for explaining a problem of a mounting structure in a conventional display device.

FIG. 6 is a schematic cross-sectional view for explaining the problem of the mounting structure in the display device of the comparative example. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the configuration of the display device according to the embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiment. The front device according to the embodiment of the present invention shown in FIG. 1 includes a display panel 1 and a frame 2 provided on a peripheral portion (a portion excluding a display area) of the display panel. The display panel 1 has one or two or more substrates, and the frame 2 has a support portion 2 that supports the display panel 1 on the main surface of the substrate at the periphery of the display panel 1. In the drawing, since only the supporting portion 2 of the frame 2 is shown, the frame 2 and the supporting portion 2 are denoted by the same reference numerals, and the display panel 1 and the substrate 1 are denoted by the same reference numerals. Note that the support portion 2 and the frame 2 may be formed integrally, or may be formed separately.

The support portion 2 has a flat portion 2a and a first curved portion 2b provided continuously to the flat portion 2a on the side facing the main surface of the substrate 1. The main surface of the substrate 1 is fixed directly or indirectly to the flat portion 2a. Here, it is fixed using an adhesive layer 3 formed of an adhesive.

When no external force is applied to the display panel (substrate) 1, a gap is formed between the main surface of the substrate 1 and the curved portion 2b, as schematically shown in FIG. 1 (a). . This gap is formed so as to become wider as it approaches the display portion (center) of the display panel 1.

When an external force is applied to the center of the display panel 1, the display panel 1 is deformed, as schematically shown in FIG. 1 (b). Here, the support portion 2 has a curved portion 2b on the display portion side, and has a gap between the support portion 2 and the main surface of the substrate 1 that becomes wider toward the display portion side. Deformation is not hindered by the support portion 2 and can be deformed freely. Further, even if the deformation is hindered by the support portion 2, the substrate 1 comes into contact with the curved portion 2b in FIG. 1 (c), so that stress is not concentrated on the substrate 1.

As described above, in the display device according to the embodiment of the present invention, the display panel (substrate) is not easily damaged even when an external force is applied. Therefore, the display device is preferably applied to a flexible display using a composite plastic substrate. A plastic substrate including a mold plastic substrate generally has moisture permeability, so that an inorganic film is formed on the surface thereof, and circuit elements are formed on the inorganic film. In such a case, a problem may occur that the inorganic film is broken before the substrate is broken, but according to the embodiment of the present invention, an effect of suppressing such a problem is also obtained. .

The width of the flat portion 2a of the support portion 2 is set so as to stably fix the substrate 1, and the width of the first curved portion 2b, if the surface facing the main surface of the substrate 1 is a curved surface, (The width of the portion where the curved portion is projected on the main surface of the substrate 1) may be narrow. For example, when the diagonal is 3 inches and the thickness of the substrate 1 is 0.2 mm, the width of the flat portion 2a is 3 mm to 5 mm. When the thickness of the substrate 1 is about 0.1 mm to about 0.5 mm, the effect of the present invention is remarkably obtained.

The material for forming the support 2 is not particularly limited, but it is preferable to use a material having elasticity. In addition to the effect of forming the curved portion 2b in the support portion 2, as shown in FIG. 5, an effect of reducing external force and impact can be obtained by deformation of the support portion 12. As the material having elasticity, for example, rubber such as silicone-based polyurethane is used. (Elastomer) can be suitably used. Further, it is preferable that the adhesive layer 3 also uses an elastic adhesive (including an adhesive). If the adhesive layer 3 having a pressure of about 20 m is formed using an adhesive, the adhesive layer 3 is easily deformed and does not give stress to the substrate 1.

However, when the adhesive layer 3 is formed using an adhesive, it is preferable to adopt the configuration shown in FIG.

In the configuration shown in FIGS. 2A and 2B, the adhesive layer 3 is formed only on the flat portion 2 a of the support portion 2, and the adhesive layer 3 is not formed on the curved portion 2 b . By adopting such a configuration, as shown in FIG. 2 (b), when the display panel 1 is deformed to the extent that it comes into contact with the curved portion 2b, the display panel 1 is formed of an adhesive. Adhesion and fixation to the adhesive layer 3 can be prevented.

Further, other configurations shown in FIGS. 3A and 3B may be adopted.

In the configuration shown in FIG. 3A, the support portion 2 has a curved portion 2b on the side facing the main surface of the substrate 1, and has a curved portion 2c facing the curved portion 2b. When such a configuration is adopted, the end of the support portion 2 (the portion where the curved portions 2b and 2c are formed) is not fixed, so that the display panel 1 comes into contact with the end of the support portion 2 Even in the case of deformation, the end can be easily deformed, so that generation of stress on the display panel 1 can be suppressed. In order to obtain such an effect, it is preferable that the support portion 2 is formed of an elastic material.

In the configuration shown in FIG. 3 (b), when the display panel 1 is deformed most, the support 2 does not hinder the deformation of the display panel 1.

0 In other words, the curvature of the curved portion 2b is increased (the radius of curvature is reduced) and the tip of the support portion 2 is cut off so that stress is not generated in the display panel 1. When such a configuration is employed, the width of the support portion 2 projecting inward (toward the display portion) can be reduced, so that breakage can be suppressed without enlarging the outer shape of the entire display device.

In the above embodiment, the configuration in which the display panel 1 is supported on the main surface of the substrate 1 of the display panel 1 opposite to the viewer side has been exemplified. Here, "supported by the main surface of the substrate" means that the main surface of the substrate 1 does not need to directly contact the support portion 2 of the frame, and the force from the support portion 2 is directly applied to the main surface of the substrate 1 or By acting indirectly (by giving a reaction to the gravity of the substrate 1), the support part 2 supports the display panel 1 in a broad sense. Therefore, when the display panel 1 is a liquid crystal panel and a polarizing plate or an optical film is provided outside the lower plastic substrate of the liquid crystal panel, the display panel 1 is bonded to the support portion 2 by the bonding layer 3. Even with a polarizing plate or an optical film, the liquid crystal panel 1 is supported on the main surface of the substrate by the support 2.

Also, in the above embodiment, the case where the peripheral portion of the display panel 1 is fixed to the frame on the main surface of the substrate opposite to the observer side is exemplified. The case where the display panel 1 is fixed to the frame on the main surface of the observer side Alternatively, the same effect can be obtained even when fixing with the main surfaces on both sides (the main surface on the substrate side when there is one substrate, and the main surface on each side when there are two substrates). Can be. In the above embodiment, the configuration in which the display panel 1 is fixed to the frame 2 using the adhesive layer 3 is employed, but the configuration for fixing the display panel 1 to the frame 2 is not limited to this. For example, a transparent plate (preferably having an opening corresponding to the display unit) is arranged on the upper surface (observer side) of the display panel 1, and the display panel is sandwiched between the plate and the frame. May be screwed.

Further, as shown in FIG. 4, a reinforcing plate made of plastic or metal having a size equal to or larger than that of the display panel 1 may be provided between the display panel 1 and the support portion 2. . The reinforcing plate 4 is directly or indirectly fixed to the flat portion 2a of the support portion 2, and when no external force is applied to the display panel 1, the reinforcing plate 4 and the curved portion 2b of the support portion 2 are connected to each other. A gap is formed between them. The display panel 1 is fixed to the reinforcing plate 4 via an adhesive layer 3 provided outside the display unit, for example. The reinforcing plate 4 may be provided on the display panel 1 on the observer side, on the opposite side to the observer, or on both sides.

The reinforcing plate 4 preferably has a rigidity equal to or higher than that of the substrate 1 of the display panel. The thickness may be set according to the Young's modulus of the material of the reinforcing plate 4 so that the flexibility required for the display device in a state where the reinforcing plate 4 is provided is not impaired. In the case of mopile use, the thickness of the reinforcing plate 4 is, for example, 0.1 mm to 0.5 mm in consideration of the thickness and lightness of the display device.

When such a configuration is adopted, unlike the configuration using the support portions 22 having corners as shown in FIG. 6, when the reinforcing plate 4 is deformed, the reinforcement is performed. The stress is prevented from being concentrated on the portion where the plate 4 comes into contact with the support portion 2, and the breakage of the reinforcing plate 4 can be suppressed.

When the reinforcing plate 4 breaks, stress concentrates on the display panel 1 at the broken portion, and the display panel (substrate) 1 may be damaged. If the plate 4 is soft, it is less likely to break, but the effect of capturing the substrate 1 is poor. Conversely, when the rigidity of the reinforcing plate is high, a flexible display cannot be constructed. Thus, when the configuration shown in FIG. 6 is adopted, it is difficult to select an appropriate material (degree of rigidity) and thickness of the reinforcing plate 4.

On the other hand, as shown in Fig. 4, when the curved portion 2b is provided at the end of the support portion 4, stress is not concentrated on the reinforcing plate 4, so that the options of the reinforcing plate 4 are expanded, and the reinforcing plate 4 is expanded. The effect as described above can also be sufficiently obtained. In FIG. 4, the display panel 1 is fixed to the reinforcing plate 4 by using the adhesive layer 3, but another configuration may be used without providing the adhesive layer 3. The same applies to the configuration in which the reinforcing plate 4 is fixed to the support portion 2. An adhesive layer may be used, or another configuration may be used. As another configuration, the screwing described above can be exemplified.

Further, in the configuration shown in FIG. 4, the end portion of the display panel 1 is in a positional relationship overlapping the flat portion 2a of the support portion 2, but even in the non-overlapping position, the reinforcing plate 4 The same effect can be obtained if it is fixed to the flat portion 2a.

The present invention is particularly applicable to a display device provided with a composite plastic substrate characterized in that the deformation amount is larger than that of a conventional glass substrate. Although it has a remarkable effect, breakage can be suppressed even in a display device having a glass substrate. Industrial applicability

As described above, according to the present invention, there is provided a display device that is less likely to be damaged when an external force or the like is applied to the front panel. INDUSTRIAL APPLICABILITY The present invention is suitably applied to a flexible display using a composite plastic substrate characterized by having a larger deformation amount than a conventional glass substrate.

Claims

The scope of the claims

1. A display panel having a substrate, and a frame having a supporting portion at a peripheral portion of the display panel for supporting the display panel on a main surface of the substrate,

The support section has a flat section on a side facing the main surface of the substrate, and a first curved section provided continuously to the flat section,

The main surface of the substrate is directly or indirectly fixed to the flat portion, and between the main surface of the substrate and the first curved portion when no external force is applied to the substrate. A display device in which a void is formed.

2. The display device according to claim 1, wherein the support section has a second curved section facing the first curved section.

3. The display device according to claim 1, wherein the main surface of the substrate is fixed to the flat portion via an adhesive layer.

4. The display device according to claim 1, further comprising a reinforcing plate between the main surface of the substrate and the flat portion of the support portion.

5. The display device according to claim 4, wherein the reinforcing plate is fixed to the flat portion via an adhesive layer.

6. The display device according to claim 1, wherein the support portion is formed of an elastic body.

7. The display device according to any one of claims 1 to 6, wherein the substrate is a plastic substrate.