HK1160936B - Image display and producing method thereof - Google Patents

Description

Image display device and method for manufacturing the same

The scheme is a divisional application of a parent case as follows:

application date: 16 days 7 month in 2008

Application No.: 200880024815.6

The invention name is as follows: an image display device and a method of manufacturing the same.

Technical Field

The present invention relates to an image display device having an image display panel such as a liquid crystal display panel and a method of manufacturing the same, and more particularly, to an improvement in an image display device in which a cured resin is interposed between an image display panel and a transparent protective panel and a method of manufacturing the same.

Background

In an image display device such as a liquid crystal display device, a transparent protective panel such as a glass panel or a plastic panel is provided on the front surface of the image display panel in order to prevent damage to the image display panel or the surface of the protective panel. Specifically, for example, a spacer (spacer) is inserted between the image display panel and the protection panel at a peripheral portion of the image display panel, whereby the protection panel is attached to the case with a slight gap from the image display panel.

However, in the case of such a structure, light is scattered due to the presence of a gap between the image display panel and the protective panel, and as a result, contrast and luminance are reduced, which causes a problem that image quality is impaired. In addition, in such a structure having a void, reflection occurs at the interface between the protective panel and air due to the difference in refractive index between the protective panel and air, and visibility is deteriorated particularly outdoors.

In response to such a situation, a technique of filling a resin between the image display panel and the protective panel has been proposed. For example, in the liquid crystal display device described in patent document 1, a spacer is disposed around a polarizing plate attached to the surface of a liquid crystal display panel, a surface protective glass is placed on the spacer, and an adhesive is filled between the polarizing plate and the surface protective glass so as not to generate air bubbles, whereby the surface protective glass is attached to the liquid crystal display panel.

Patent document 2 also discloses an image display device in which an image display panel and a protective panel are attached to each other with at least 1 layer or more of a transparent adhesive interposed therebetween, and describes a technique for achieving excellent impact resistance by setting the thickness of the transparent adhesive and the dynamic viscoelastic characteristics measured at different frequency distributions to a predetermined relationship.

Patent document 1: japanese unexamined patent publication No. 2005-55641

Patent document 2: japanese laid-open patent publication No. 2003-29644

However, it is more advantageous to use a plastic panel than a glass panel as a protective panel from the viewpoint of manufacturing cost, impact resistance, and the like. Glass panels are expensive and have poor impact resistance compared to plastic panels. Therefore, a technique of using a plastic panel formed of polymethyl methacrylate (PMMA), which is one kind of acrylic resin, as a protective panel is under study.

However, the use of a plastic panel as the protective panel causes a problem of warping of the protective panel, which causes deterioration of display quality. For example, when a resin composition is filled between the image display panel and the plastic panel and cured, internal stress due to volume shrinkage, external stress due to warping of the plastic panel due to a change in environmental temperature, residual stress of the plastic panel itself during molding, and the like are applied to the image display panel when the resin composition is cured. When such internal stress, external stress, or residual stress is applied to the image display panel, the liquid crystal cell gap of the liquid crystal layer fluctuates in the order of nanometers when the image display panel is a liquid crystal display panel, which causes display unevenness.

In particular, when the size of the protection panel is set to be larger than the size of the image display panel and the light shielding portion is provided in the outer peripheral portion of the protection panel, the tendency of occurrence of display unevenness becomes more remarkable in some cases. In addition, in an extreme case, the outer peripheral portion of the protective panel may be lifted up, causing light leakage and the like.

In order to suppress the volume shrinkage of the resin composition filled between the image display panel and the protective panel, it has been attempted to use a resin composition having a low curing shrinkage rate and a low elastic modulus. This is because a plastic panel such as a polymethyl methacrylate panel is easily warped by a change in environmental temperature (particularly, when exposed to high temperature), and the resin composition filled between the image display panel and the protective panel is easily warped at high temperature even when cured by ultraviolet irradiation, and further easily warped at high temperature even after cured.

Disclosure of Invention

The present invention has been made in view of the above-described conventional circumstances, and an object thereof is to provide a configuration of an image display device capable of minimizing warpage of a protective panel formed of plastic, and further to provide a method for manufacturing the image display device.

In order to achieve the above object, the 1 st image display device according to the present invention is an image display device in which an image display panel and a transparent protective panel made of plastic are disposed to face each other with a cured resin interposed therebetween, wherein the protective panel has an outer dimension larger than that of the image display panel, and the outer peripheral edge portion is fixed by a fixing jig.

The method of manufacturing an image display device according to the 1 st aspect of the present invention is a method of manufacturing an image display device including a step of disposing an image display panel and a transparent protective panel made of plastic opposite to each other with a cured resin material interposed therebetween and curing the resin composition, wherein the outer dimension of the protective panel is made larger than the outer dimension of the image display panel, and the resin composition is cured in a state where the outer peripheral edge portion of the protective panel is fixed by a fixing jig.

The 2 nd image display device according to the present invention is an image display device in which an image display panel and a transparent protective panel made of plastic are disposed to face each other with a cured resin interposed therebetween, wherein the protective panel has an outer dimension substantially equal to an outer dimension of the image display panel, the outer dimension being equal to an inner dimension of a case for the protective panel and the image display panel, and substantially the entire surface of the protective panel is bonded to the image display panel with the cured resin.

A method for manufacturing an image display device according to the 2 nd aspect of the present invention is a method for manufacturing an image display device including a step of disposing an image display panel and a transparent protective panel made of plastic opposite to each other with a cured resin material interposed therebetween and curing the resin composition, wherein the outer dimension of the protective panel is made substantially equal to the outer dimension of the image display panel and the outer dimension is made substantially equal to the inner dimension of a case for protecting the panel and the image display panel, and the resin composition is cured in the case in a state where substantially the entire surface of the protective panel is in contact with the cured resin material.

In addition, in the present invention, "the outer dimension of the protective panel is larger than the outer dimension of the image display panel" means that the image display panel is included in the protective panel in a case where the protective panel and the image display panel are overlapped in a plan view.

Effects of the invention

As described above, in the case where the size of the protection panel is larger than that of the image display panel, the peripheral edge portion of the protection panel is significantly warped. Therefore, in the image display device or the manufacturing method thereof according to the invention 1, the resin composition is cured by ultraviolet irradiation or the like in a state where the outer peripheral edge portion of the protective panel is fixed by the fixing jig, and the outer peripheral edge portion is also fixed by the fixing jig after the curing. Thus, the resin composition can be cured while the warp of the protective panel is corrected, and the protective panel can be maintained in an unbent state.

On the other hand, in the 2 nd image display device or the method of manufacturing the same according to the present invention, focusing on the size of the protection panel, the size of the image display panel, and the size of the housing thereof, the outer dimension of the protection panel is made substantially equal to the outer dimension of the image display panel and the inner dimension of the housing thereof, and the cured resin is not cured in a state where the cured resin is in contact with the almost entire surface of the protection panel, so that the resin curing is performed in a state where the outer peripheral edge portion of the protection panel is still open, and further, the upward lifting of the protection panel can be suppressed from the side surface of the protection panel (the surface in contact with the housing) only by fitting the protection panel and the image display panel into the housing via the resin composition, and therefore, even if the fixing means of the protection panel is not taken in particular, the resin curing can be performed uniformly over the entire surface of the protection panel, the occurrence of warpage is suppressed.

As described above, the conventional technique does not disclose any idea of making the outer dimension of the protective panel substantially equal to the outer dimension of the image display panel and the inner dimension of the housing thereof, thereby suppressing the occurrence of warpage in the protective panel. For example, in the invention described in patent document 1, the surface protection glass is used, but the problem of warping of the plastic panel is not considered at all. The invention described in patent document 2 is directed to an image display device having a large screen of about 32 to 100 inches, and the size of the protection panel is smaller than that of the display panel, and a structure different from the invention of the present application is adopted, and therefore, a protection structure of the image display panel cannot be manufactured by a simple operation of merely fitting the protection panel and the image display panel into a case via a member formed by overlapping a resin composition.

Therefore, according to the 1 st and 2 nd image display devices of the present invention, even if the protective panel is formed of plastic, the warp of the protective panel can be reliably suppressed, and highly reliable graphic display without causing problems such as display unevenness can be realized. In addition, according to the method for manufacturing an image display device of the present invention, such an image display device can be provided.

In addition, according to the 1 st and 2 nd image display devices of the present invention, since the cured resin is interposed between the protective panel and the image display panel, a corresponding effect can be obtained thereby. For example, reflection occurring at the interface of the protective panel can be suppressed, and visibility outdoors can be sufficiently ensured. Further, the resin cured product is interposed between the protective panel and the image display panel, and sufficient impact resistance and the like can be secured even if the distance between the protective panel and the image display panel is small as compared with the case where a gap is formed therebetween. Therefore, the device can be made thin.

Drawings

Fig. 1 is a schematic diagram of a panel structure of a liquid crystal display device according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing a process of attaching the protective panel in the embodiment of fig. 1.

Fig. 3 is a schematic view of a panel structure of a liquid crystal display device according to another embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view showing a process of attaching the protective panel in the embodiment of fig. 3.

Fig. 5 is a schematic cross-sectional view showing a process of attaching a protective panel to a liquid crystal display device according to another embodiment of the present invention.

Fig. 6 is a schematic sectional view for explaining warpage of the protection panel.

Description of reference numerals

1 … … liquid crystal display panel

2 … … protection panel

2a … … light-shielding part

3 … … hardened resin

4 … … resin composition

5.6 … … fixing clamp

5a … … buckling part

7 … … adhesive tape

8 … … case.

Detailed Description

An embodiment of an image display device and a method for manufacturing the same to which the present invention is applied will be described below with reference to the accompanying drawings by taking a liquid crystal display device as an example. In the drawings, the same reference numerals are used for the same or equivalent structural elements.

Fig. 1 is a schematic diagram of a panel structure of a liquid crystal display device according to embodiment 1 of the present invention. The liquid crystal display device is used for a mobile phone, a portable game machine, or the like, and includes a liquid crystal display panel 1 for displaying an image and a protective panel 2 for protecting the surface of the liquid crystal display panel 1, which are arranged to face each other with a cured resin 3 interposed therebetween and are bonded to substantially the entire surface of the surface or the back surface of the cured resin 3, respectively, thereby improving visibility and impact resistance.

In the liquid crystal display panel 1, a liquid crystal layer LC is formed between a pair of substrates 11 and 12 with a liquid crystal material interposed therebetween, and an image is displayed by controlling the orientation of the liquid crystal material in the liquid crystal layer LC. More specifically, a color filter or a black matrix, a pixel electrode or a counter electrode, a driving transistor, and the like, which are not shown, are provided between the pair of substrates 11 and 12, and polarizing plates are attached to the front and rear surfaces thereof, and each pixel is driven by, for example, an active matrix method, thereby displaying an image. The gap g between the pair of substrates 11 and 12 is a so-called liquid crystal cell gap.

In the image display device, a light shielding portion 2a is formed at the outer peripheral edge portion of the protective panel 2. The outer dimension W2 of the protection panel 2 including the light shielding portion 2a is slightly larger than the outer dimension W1 of the liquid crystal display panel 1, and the light shielding portion 2a projects outward from the inside of the outer peripheral edge of the liquid crystal display panel 1, and light leakage from the outer peripheral portion of the liquid crystal display panel 1 is reliably shielded by the light shielding portion 2 a.

In the case where the peripheral edge portion of the protective panel 2 protrudes from the peripheral edge portion of the liquid crystal display panel 1 in this manner, when the protective panel 2 and the liquid crystal display panel 1 are bonded together only by inserting the resin composition therebetween and curing the resin composition, as shown in fig. 6, the resin cured product 3 is lifted particularly at the peripheral portion of the protective panel 2 due to internal stress (arrow a) generated when the resin composition is cured or external stress (arrow B) generated at the peripheral portion of the protective panel 2 when the protective panel 2 is warped due to a change in the environmental temperature, and these stresses are applied to the upper surface of the liquid crystal display panel 1. When the liquid crystal display panel 1 is subjected to such stress, the gap g between the substrates 11 and 12 of the liquid crystal display panel 1 may fluctuate on a nanometer scale, for example, at the central portion and the peripheral portion, and display unevenness may occur.

In contrast, in the present embodiment, the resin composition is cured in a state where the upper surface of the light shielding portion 2a of the protective panel 2 (i.e., the surface of the protective panel 2 on the opposite side of the liquid crystal display panel 1) is pressed against the liquid crystal display panel 1 side by the fixing jig 5, thereby preventing the protective panel 2 from warping during curing and minimizing the stress applied to the liquid crystal display panel 1. Further, after the resin composition is cured, as shown in fig. 1, the upper surface of the light shielding portion 2a is continuously pressed and fixed by the fixing jig 5. Therefore, according to the present embodiment, the outer peripheral edge portion of the protection panel 2 can be maintained in a state of not being warped. The method of attaching the protective panel in the present embodiment will be described in detail below.

Fig. 2 shows a process of attaching the protective panel 2 in the method of manufacturing the liquid crystal display device according to the present embodiment. In this step, first, the resin composition 4 is applied between the liquid crystal display panel 1 and the protective panel 2. In this case, the protective panel 2 may be overlaid on the upper surface of the liquid crystal display panel 1 after the resin composition 4 is applied thereto, or conversely, the protective panel 2 may be overlaid on the liquid crystal display panel 1 after the resin composition 4 is applied thereto on the side of the protective panel 2 and reversed.

The resin composition 4 to be used may be a thermosetting resin composition, a photo-curing resin composition (e.g., an ultraviolet curing resin composition), or the like. However, from the viewpoint of avoiding a high temperature state at the time of curing as much as possible, it is preferable to use a photocurable resin composition such as an ultraviolet-curable resin composition. In this embodiment, an ultraviolet curable resin composition is also used as the resin composition 4.

The curing shrinkage of resin composition 4 used for preparation is preferably 5% or less, more preferably 4.5% or less, still more preferably 4.0% or less, and most preferably 0 to 2%. This reduces the internal stress accumulated in the cured resin 3 when the resin composition 4 is cured, and prevents the interface between the cured resin 3 and the liquid crystal display panel 1 or the interface between the cured resin 3 and the protective panel 2 from being deformed.

Further, as resin composition 4, a resin composition prepared as follows was used: the storage modulus of elasticity (25 ℃) of the cured resin 3 is preferably 1X 10⁷Pa or less, more preferably 1X 10³Pa～1×10⁶Pa. Thereby, the stress applied to the liquid crystal display panel 1 after the resin composition 4 is cured can be reduced.

Further, the resin composition 4 may be dropped on a flat plate, and the degree of internal stress accumulated in the cured resin 3 during curing of the resin composition may be evaluated based on the average surface roughness of the cured resin obtained by curing the resin composition. For example, when 2mg of the resin composition is dropped on a glass plate constituting a substrate of a liquid crystal display panel or an acrylic plate constituting a protective panel and then cured by ultraviolet irradiation at a curing rate of 90% or more, if the average surface roughness of the obtained cured resin is 6.0nm or less, preferably 5.0nm or less, and more preferably 1 to 3nm, the distortion occurring at the interface with the liquid crystal display panel 1 or the protective panel 2 can be controlled to a level that is negligible in practical use. In this case, the average surface roughness of the glass plate or the acrylic plate is usually 1.0nm or less. Therefore, the average surface roughness of the cured resin in the case where the resin composition 4 used in the present invention is dropped on a glass plate or an acrylic plate constituting a substrate of a liquid crystal display panel is also within the above range.

The resin composition 4 also needs to have excellent optical characteristics. For example, the refractive index of the cured resin 3 formed by curing the resin composition 4 is preferably about the same as the refractive index of the liquid crystal display panel 1 or the protective panel 2. For example, when the substrate 11 of the liquid crystal display panel 1 is formed of optical glass, the refractive index (nD) thereof is 1.49 to 1.50, and when the substrate is formed of tempered glass, it is about 1.55, and when the protective panel 2 is formed of acrylic resin, the refractive index (nD) thereof is 1.51 to 1.52, and therefore, the refractive index (nD) of the cured resin 3 is preferably 1.45 or more and 1.55 or less, and more preferably 1.51 or more and 1.52 or less.

In addition, in terms of transparency, when the thickness of the cured resin 3 is set to 100 μm, the transmittance of light in the visible light wavelength range is preferably 90% or more.

Examples of the resin composition satisfying the above conditions include a resin composition containing one or more polymers selected from urethane acrylate, polyisoprene acrylate (polyisoprene acrylate) or an esterified product thereof, hydrogenated terpene resin (hydrogenated terpene resin), and butadiene polymer, a monomer selected from Isobornyl acrylate, 2-methyl-2-propenoate (2,3,3A,4,7, 7A-hexahydro-4, 7-methylene-1 hydro-indenyl) oxy ethyl acrylate (dicycloethoxy-methacrylate), and 2-methyl-2-propenoate (2-hydroxy butyl acrylate), and a photopolymerization initiator such as 1-hydroxycyclohexyl-phenyl-ketone An olefinic acid ester monomer.

In this case, the kind, ratio, etc. of the polymer or the acrylate monomer are adjusted so that the values of the curing shrinkage, storage elastic modulus, and optical characteristics fall within the above-mentioned ranges. In addition, since the protective panel 2 is often provided with a function of intercepting light in the ultraviolet region from the viewpoint of protecting the liquid crystal display panel 1 from ultraviolet rays, it is preferable to use a photopolymerization initiator that is also hardened by the action of light in the visible region (for example, a product name called Speed Cure TPO manufactured by siber corporation, japan).

When the resin composition 4 is applied to the liquid crystal display panel 1 or the protective panel 2, for example, a spacer is formed around the liquid crystal display panel 1, and the resin composition 4 is applied. Of course, the spacers may also be omitted. The thickness of the resin composition 4 to be coated is arbitrary, but it is preferable to coat the cured resin 3 so that the layer thickness is about 50 μm to 200 μm.

After the resin composition 4 is applied, the liquid crystal display panel 1 and the protective panel 2 are stacked with the resin composition 4 interposed therebetween. Here, the protective panel 2 is a transparent panel made of plastic, and for example, an acrylic panel such as a polymethyl methacrylate panel can be used. In the present embodiment, a panel having a light shielding portion 2a for shielding light at its outer peripheral edge portion is used as the protective panel 2. The light-shielding portion 2a may be formed by, for example, attaching a light-shielding tape or printing a light-shielding paint.

Since the outer dimensions of the protective panel 2 are larger than the outer dimensions of the liquid crystal display panel 1, the outer peripheral edge portion of the protective panel 2 protrudes from the outer peripheral edge portion of the liquid crystal display panel 1 after they are stacked, and in this state, if the resin composition 4 is cured by merely irradiating ultraviolet rays and is bonded to the protective panel 2, there is a problem that the protective panel 2 is warped. Therefore, in the present embodiment, as shown in fig. 2, the resin composition 4 is cured while the outer peripheral edge portion of the protective panel 2 is fixed by pressing it from the upper surface of the protective panel 2 using the fixing jig 5.

More specifically, as the fixing jig 5, for example, a frame-shaped member capable of accommodating the liquid crystal display panel 1 or the protective panel 2 therein may be used, and the upper end portion may be bent into an eave-shaped pressing portion 5 a. The upper surface of the outer peripheral edge portion of the protective panel 2 serving as the light shielding portion 2a is pressed by the pressing portion 5a, and the resin composition 4 is cured by irradiation of ultraviolet rays. Thus, since the curing of the resin composition 4 is performed in a state where the warpage of the protective panel 2 has been corrected, the flatness of the protective panel 2 is maintained. Even when the resin composition is cured by ultraviolet irradiation, the protective panel 2 is actually exposed to heat, but if the light shielding portion 2a is fixed by the fastening portion 5a in advance, the warpage does not increase even when the protective panel 2 is heated to a high temperature.

The fixing jig 5 may be a dedicated jig used only when the resin composition 4 is cured, or may be a case for accommodating the liquid crystal display panel 1 to which the protective panel 2 is attached. The pressed state can be obtained by forming the eaves-like pressing portion 5a in advance in a case of a liquid crystal display device in which the liquid crystal display panel 1 is assembled, and assembling the liquid crystal display panel 1 and the like in the case. In this case, the case can be used as it is, and the liquid crystal display panel 1 is assembled together with the curing of the resin composition 4. That is, the state of fig. 2 is directly the structure of the liquid crystal display device. In this case, the upper surface of the protection panel 2 is supported and fixed by the case after the resin composition 4 is cured, and the protection panel 2 can be prevented from warping with time.

The liquid crystal display device manufactured in the above manner can reliably suppress the warpage of the protective panel 2, and thus a highly reliable liquid crystal display device in which problems such as display unevenness do not occur can be obtained. Further, since the space between the protective panel 2 and the liquid crystal display panel 1 is filled with the cured resin 3, it is possible to ensure impact resistance while sufficiently ensuring visibility in outdoor places.

Fig. 3 is a schematic view of a panel structure of an image display device according to embodiment 1 of the present invention. This image display device is different from the image display device of fig. 1 in that the lower surface of the peripheral edge portion of the protective panel 2 formed of plastic, that is, the surface of the protective panel 2 on the image display panel 1 side is adhesively fixed to the upper end surface of the fixing jig 6, and they are formed in the same manner except that these are different.

The method of attaching the protective panel 2 in this embodiment is to apply the resin composition 4 in the same manner as described above and then to overlap the liquid crystal display panel 1 and the protective panel 2 with the resin composition 4 interposed therebetween, but in this case, as shown in fig. 4, a frame-shaped fixing jig 6 having substantially the same outer dimension as the protective panel 2 is used, and the outer peripheral edge portion of the protective panel 2 is fixed by the upper end face of the fixing jig 6. For example, an adhesive tape 7 is previously stuck to the upper end surface of the fixing jig 6 to bond and fix the protective panel 2. As long as the ultraviolet irradiation is performed to cure the resin composition 4 in this state, the warpage of the protective panel 2 can be reliably suppressed as in the case of the embodiment of fig. 1.

In the present embodiment, the fixing jig 6 may be a dedicated jig used only when the resin composition 4 is cured, or may be a case for accommodating the liquid crystal display panel 1. In the latter case, the state of fig. 3 is directly a structure of the liquid crystal display device.

Fig. 5 is a schematic diagram of a method for manufacturing a panel structure of a liquid crystal display device according to embodiment 2 of the present invention. A characteristic feature of the present embodiment is that, in the present embodiment, the outer dimensions of the protective panel 2 are set to be substantially equal to the outer dimensions of the liquid crystal display panel 1, and these outer dimensions are set to be substantially equal to the inner dimensions of the housing 8, and the cured resin 4 is cured in a state where the cured resin 4 is in contact with substantially the entire surface of the protective panel 2. The steps before coating the resin composition 4 are also the same as those in the case of embodiment 1 of the present invention, and therefore, the description thereof is omitted here.

As described above, after the resin composition 4 is applied to the liquid crystal display panel 1, the protective panel 2 is superimposed thereon, and at this time, as shown in fig. 5, the outer dimension of the protective panel 2 is set to be substantially equal to the outer dimension of the liquid crystal display panel 1. Thus, the entire surface of the protective panel 2 is in contact with the resin composition 4, and is in a state free from warpage. In this state, is accommodated in the case 8. Here, the inside dimension of the case 8 is set to be substantially equal to the outer dimension of the protective panel 2 or the liquid crystal display panel 1, and the protective panel 2 superimposed on the liquid crystal display panel 1 is fitted into the case 8. In this state, the resin composition 4 is cured by irradiation with ultraviolet rays, and the warpage of the protective panel 2 can be suppressed easily and reliably. This is because there is no protruding portion of the protective panel 4 where warpage is noticeable, and warpage of the protective panel 2 is suppressed by the case 8 abutting against the side surface thereof. In the case of this embodiment, a light shielding portion must be separately provided.

While the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the light-shielding portion may be omitted in the peripheral edge portion of the protective panel. The above embodiments are all embodiments in which the present invention is applied to a liquid crystal display device, but the present invention can also be applied to devices other than a liquid crystal display device, for example, an organic EL display device, a plasma display device, or the like.

Examples

Next, specific examples of the present invention will be described based on the test results.

(example 1)

The protective panel was attached to the liquid crystal display panel in accordance with the method shown in fig. 2, and the liquid crystal display device was manufactured. The protective panel used was a transparent plastic panel formed using polymethyl methacrylate (PMMA). As a fixing jig, a case for housing the liquid crystal display panel is used, and an eave-shaped fastening portion is formed in the case, thereby pressing and fixing an upper surface of a light shielding portion formed at a peripheral edge portion of the protective panel.

As a resin composition interposed between a liquid crystal display panel and a protective panel, a resin composition was prepared by stirring a maleic anhydride adduct of a polyisoprene polymer and an esterified product of 2-methyl-2-propenoic acid-2-hydroxyethyl ester 70 weight units, 2-methyl-2-propenoic acid-2 [ (2,3,3A,4,7, 7A-hexahydro-4, 7-methylene-1-hydro-indenyl) oxy ] ethyl ester 30 weight units, 2-methyl-2-propenoic acid-2-hydroxybutyl ester 10 weight units, hydrogenated terpene resin 30 weight units, butadiene polymer 140 weight units, photopolymerization initiator 4 weight units, and visible light region photopolymerization initiator 0.5 weight units with a stirrer.

The resin composition has a curing shrinkage of 1.8%, and the storage modulus (25 ℃) of the cured resin obtained by curing the resin composition is 1X 10⁴Pa. When 2mg of the resin composition was dropped on a glass plate for a liquid crystal cell and cured by ultraviolet irradiation at a curing rate of 90% or more, the average surface roughness of the resulting cured resin was 2.7 nm. Further, a cured resin having a thickness of 100 μm was formed from the resin composition, and when the transmittance in the visible light range was measured by an ultraviolet-visible spectrophotometer (product name V-560, manufactured by JASCO corporation), the result was 90% or more.

Further, the storage elastic modulus was measured at a measurement frequency of 1Hz using a viscoelasticity measuring apparatus (product name DMS6100, manufactured by Seiko electronics Co., Ltd.) to obtain an elastic modulus (Pa) (25 ℃).

The curing shrinkage was calculated from the difference between the specific gravities of the resin liquid before curing and the solid after curing by measuring the specific gravities of the resin liquid and the solid using an electronic densitometer (product name SD-120L, manufactured by MIRAGE).

Hardening shrinkage (%) = (hardened material specific gravity-specific gravity of resin liquid)/hardened material specific gravity × 100

The average surface roughness was obtained by measuring the deformation (Ra: average surface roughness) of a predetermined region (2.93 mm. times.2.20 mm) of the surface of the glass plate using a three-dimensional non-contact surface roughness measuring instrument manufactured by Zygo corporation.

According to this embodiment, the protective panel is substantially free from warpage, and a liquid crystal display device free from display unevenness and excellent in outdoor visibility and impact resistance can be obtained.

(example 2)

The resin composition interposed between the liquid crystal display panel and the protective panel was changed in the following manner, and the other points were the same as in example 1, thereby manufacturing a liquid crystal display device. In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

That is, in this example, a resin composition was prepared by stirring 100 parts by weight of an esterified product of a maleic anhydride adduct of a polyisoprene polymer and 2-methyl-2-propenoic acid-2-hydroxyethyl ester, 30 parts by weight of 2-methyl-2-propenoic acid-2 [ (2,3,3A,4,7, 7A-hexahydro-4, 7-methylene-1 hydro-indenyl) oxy ] ethyl ester, 10 parts by weight of 2-methyl-2-propenoic acid-2-hydroxybutyl ester, 30 parts by weight of a hydrogenated terpene resin, 210 parts by weight of a butadiene polymer, 7 parts by weight of a photopolymerization initiator, and 1.5 parts by weight of a photopolymerization initiator for visible light region with a stirrer.

The resin composition has a curing shrinkage of 1.0%, and the storage modulus (25 ℃) of the cured resin obtained by curing the resin composition is 4X 10³Pa. Further, when 2mg of the resin composition was dropped on a glass plate for a liquid crystal cell and cured by ultraviolet irradiation at a curing rate of 90% or more, the average surface roughness of the resulting cured resin was 1.5 nm. Further, the transmittance of a 100 μm thick cured resin formed from the resin composition in the visible light range was measured by an ultraviolet-visible spectrophotometer (product name V-560, manufactured by JASCO corporation) and found to be 90% or more.

(example 3)

The resin composition interposed between the liquid crystal display panel and the protective panel was changed in the following manner, and the other points were the same as in example 1, thereby manufacturing a liquid crystal display device. In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

That is, in this example, 70 parts by weight of an ester compound of an anhydride maleic anhydride adduct of polyisoprene polymer and 2-methyl-2-propenoic acid-2-hydroxyethyl ester (product name UC-203, manufactured by クラレ), 30 parts by weight of 2-methyl-2-propenoic acid-2 [ (2,3,3A,4,7, 7A-hexahydro-4, 7-methylene-1 hydro-indenyl) oxy ] ethyl ester (product name FA512M, manufactured by Hitachi chemical Co., Ltd.), 10 parts by weight of 2-methyl-2-propenoic acid-2-hydroxybutyl ester (product name ライトエステル HOB, manufactured by Kyoho chemical Co., Ltd.), 30 parts by weight of hydrogenated terpene resin (product name クリアロン P-85, manufactured by ヤスハラケミカル Co., Ltd.) were mixed with a stirrer, A resin composition was prepared by stirring 35 parts by weight of a butadiene polymer (product name Polyoil 110, manufactured by Japan ゼオン Co.), 5 parts by weight of a photopolymerization initiator (product name イルガキュア 184D, manufactured by Ciba Specialty Chemicals) and 2 parts by weight of a photopolymerization initiator for visible light range (product name Speed Cure TPO, manufactured by Japan シイベルヘグナー Co.).

The resin composition had a curing shrinkage of 3.8%, and the storage modulus (25 ℃) of the cured resin obtained by curing the resin composition was 4X 10⁵Pa. Further, when 2mg of the resin composition was dropped on a glass plate for a liquid crystal cell and cured by ultraviolet irradiation at a curing rate of 90% or more, the average surface roughness of the obtained cured resin was 5.0 nm. Further, the transmittance of a 100 μm thick cured resin formed from the resin composition in the visible light range was measured by an ultraviolet-visible spectrophotometer (product name V-560, manufactured by JASCO corporation) and found to be 90% or more.

(example 4)

A liquid crystal display device was manufactured by using the same protective panel as in example 1 and attaching the protective panel to the liquid crystal display panel by the method shown in fig. 3. The resin composition used was the same as in example 1.

In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

(example 5)

A liquid crystal display device was manufactured by using the same protective panel as in example 1 and attaching the protective panel to the liquid crystal display panel by the method shown in fig. 3. The resin composition used was the same as in example 2.

In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

(example 6)

A liquid crystal display device was manufactured by using the same protective panel as in example 1 and attaching the protective panel to the liquid crystal display panel by the method shown in fig. 3. The resin composition used was the same as in example 3.

In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

(example 7)

The same protective panel as in example 1 was used, and resin curing was performed at the time of attaching the protective panel in accordance with the method shown in fig. 5, thereby manufacturing a liquid crystal display device. The resin composition used was the same as in example 1. In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

(example 8)

The same protective panel as in example 1 was used, and resin curing was performed at the time of attaching the protective panel in accordance with the method shown in fig. 5, thereby manufacturing a liquid crystal display device. The resin composition used was the same as in example 2. In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

(example 9)

The same protective panel as in example 1 was used, and resin curing was performed at the time of attaching the protective panel in accordance with the method shown in fig. 5, thereby manufacturing a liquid crystal display device. The resin composition used was the same as in example 3. In this example, the protective panel was not substantially warped, and a liquid crystal display device having no display unevenness and excellent outdoor visibility and impact resistance was obtained.

Claims (4)

1. An image display device comprising an image display panel and a transparent protective panel made of plastic arranged to face each other with a cured resin interposed therebetween,

the outer dimension of the protective panel is substantially equal to the outer dimension of the image display panel, the outer dimension is equal to the inner dimensions of the protective panel and the housing of the image display panel, almost the entire surface of the protective panel is bonded to the image display panel by the cured resin,

the cured resin is cured with ultraviolet irradiation to a shrinkage of 5%Obtained by curing the following resin composition and having a storage modulus of elasticity of 1X 10 at 25 ℃⁷The content of the compound is less than Pa,

the resin composition comprises: the acrylic resin composition comprises a polymer, an acrylate monomer and a photopolymerization initiator, wherein the polymer is more than one polymer selected from urethane acrylate, polyisoprene acrylate or an esterified product thereof, hydrogenated terpene resin and butadiene polymer, and the acrylate monomer is more than one monomer selected from isobornyl acrylate, 2-methyl-2-acrylic acid-2 [ (2,3,3A,4,7, 7A-hexahydro-4, 7-methylene-1 hydro-indenyl) oxy ] ethyl ester and 2-methyl-2-acrylic acid-2-hydroxybutyl ester.

2. The image display device according to claim 1, wherein the protective panel is formed of polymethyl methacrylate.

3. The image display device according to claim 1 or 2, wherein the image display panel is a liquid crystal display panel.

4. A method for manufacturing an image display device, comprising a step of disposing an image display panel and a transparent protective panel made of plastic opposite to each other with a resin composition interposed therebetween, and curing the resin composition to form a cured resin,

the outer dimension of the protection panel is made substantially equal to the outer dimension of the image display panel, and the outer dimension is made substantially equal to the inner dimensions of the protection panel and the housing of the image display panel,

in the case, the resin composition is cured in a state where almost the entire surface of the protective panel is in contact with the resin composition,

the cured resin is obtained by curing a resin composition having a curing shrinkage of 5% or less by irradiation with ultraviolet rays, and has a storage elastic modulus of 1X 10 at 25 DEG C⁷The content of the compound is less than Pa,

the resin composition comprises: the acrylic resin composition comprises a polymer, an acrylate monomer and a photopolymerization initiator, wherein the polymer is more than one polymer selected from urethane acrylate, polyisoprene acrylate or an esterified product thereof, hydrogenated terpene resin and butadiene polymer, and the acrylate monomer is more than one monomer selected from isobornyl acrylate, 2-methyl-2-acrylic acid-2 [ (2,3,3A,4,7, 7A-hexahydro-4, 7-methylene-1 hydro-indenyl) oxy ] ethyl ester and 2-methyl-2-acrylic acid-2-hydroxybutyl ester.