JP2013125262A - Bonding material, display element, and method for manufacturing display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase flexibility of a display element, prevent peeling and floating up of a pair of substrates between which a substance having an optical effect is interposed, and, at the same time, contribute to making a frame portion of the display element narrower.SOLUTION: A bonding material 10 is used for fixing an optical film 4 laminated onto an optical element 3 within a display region thereof, and has a region 1 that exhibits adhesion or pressure sensitive adhesion and a region 2 that exhibits tight adhesion. A display element 20 is formed by fixing and laminating an optical element 3 where a substance having an optical effect is interposed between a pair of substrates, and an optical film 4 that is laminated onto the optical element 3, by use of the bonding material 10.

Description

  The present invention relates to, for example, a bonding material for bonding an optical film to an optical element sandwiching a substance having an optical effect such as a liquid crystal layer or an organic EL layer, a display element, and a method for manufacturing the display element.

  As a display element sandwiching a substance having an optical effect, for example, a liquid crystal display element, an EL element, a microcapsule element, an electropowder fluid element, an electrowetting element, an electrophoretic element, and the like are known.

  Such a display element has a protective film, a polarizing plate, a retardation film, a light guide plate, a diffusion plate for the purpose of sandwiching a substance having an optical effect between a pair of glass substrates and enhancing the protection or optical effect on the outside. It is generally performed that optical films such as are bonded. Adhesive materials and adhesives (hereinafter referred to as “viscous / adhesive materials”) are used as the bonding material for bonding these optical films, and the display area is such that no air layer is interposed between the optical film and the substrate. The entire surface is bonded (Patent Document 1).

  During the manufacturing process of the display element, if foreign matter is mixed into the interface between the substrate and the optical film or if the optical film is stuck in the wrong position, or if the optical film itself is abnormal, the optical film is reworked. . When the optical film is peeled off during the reworking operation, stress is applied to the substrate through the adhesive layer applied to the entire surface of the optical film, so that the substrate is greatly deformed. At this time, the structure inside the display element is also deformed, resulting in display unevenness. Therefore, as a countermeasure, Patent Document 2 discloses a configuration for suppressing display unevenness in a liquid crystal display panel by setting the adhesive strength of an adhesive layer for adhering a polarizing plate to a substrate not to exceed 1000 g / 20 mm. ing.

  In Patent Document 3, a liquid crystal display panel and a polarizing plate are bonded to each other in a frame shape in order to prevent deterioration of display quality due to bubbles generated inside an adhesive layer or the like that bonds the polarizing plate to the liquid crystal display panel. The structure which bonds together with a member is disclosed.

  Further, in Patent Document 4, an adhesive layer for adhering the optical film is disposed outside the transparent substrate constituting the optical display panel when viewed from the normal direction of the display surface of the optical display panel, and the optical film and The structure which does not have a gas layer by arrange | positioning a fluid substance between the display area | regions of an optical display panel is disclosed.

  On the other hand, in recent years, demands for thinning, lightening, and robustness of mobile phones, PDAs, and public displays have been increasing. Therefore, there has been an attempt to use a thin, light and strong plastic substrate instead of a glass substrate, and some of them have been put into practical use in TN (Twisted Nematic) type and STN (Super Twisted Nematic) type liquid crystal display elements. ing. Furthermore, these display elements are increasingly required to have flexible bendability, and in a structure in which a substrate and an optical film are fixed uniformly using an adhesive or the like as in the past, The elastic modulus accompanying the deformation of the entire display element becomes too large, and there is a problem that the deformation becomes difficult or the substrates are peeled off or lifted by the deformation.

JP-A-10-186133 JP 11-119212 A Japanese Utility Model Publication No. 60-54121 JP 2009-192838 A

  The problem to be solved by the present invention is to increase the flexibility with respect to deformation of the display element and to destroy the display element accompanying the deformation, for example, a pair of substrates sandwiching a substance having an optical effect such as a liquid crystal layer or an organic EL layer An object of the present invention is to provide a bonding material, a display element, and a method for manufacturing the display element that prevent peeling or floating. At the same time, the present invention provides a bonding material, a display element, and a method for manufacturing the display element that contribute to a narrow frame of the display element.

  In order to solve the above-described problems and achieve the object, the present invention is configured as follows.

  Reduce the area of the adhesive / adhesive fixing area where optical films such as polarizing plates are bonded to the display, or reduce the number of fixing points, and at the same time fill the non-fixed area with a material that improves adhesion, and the air layer To prevent intrusion. For example, by inserting an appropriate low viscoelastic material having a low viscosity and / or elastic modulus between the adherend and the adhesive / adhesive material in the adhesive / adhesive material region to be non-fixed, In addition to being reduced, it is possible to maintain the adhesiveness and prevent display characteristics from being deteriorated by interface reflection. By reducing the area of the adhesive / adhesive fixing region, it is possible to reduce the resistance when the display is subjected to deformation such as bending.

  Invention of Claim 1 is a bonding material which fixes the optical film laminated | stacked on an optical element in the display area, and has the area | region which shows adhesiveness or adhesiveness, and the area | region which shows adhesiveness. It is a characteristic bonding material.

  Invention of Claim 2 is a bonding material of Claim 1 characterized by the distribution of the area | region which shows the said adhesiveness or adhesiveness, and the area | region which shows the said adhesiveness being a sea island structure. .

  The invention according to claim 3 is the bonding material according to claim 1, wherein the distribution of the region exhibiting adhesiveness or adhesiveness and the region exhibiting the adhesiveness are both continuous structures. is there.

  The invention according to claim 4 is a structure in which the region showing the adhesiveness or adhesiveness is an outer peripheral portion along the shape of the display region, and the region showing the adhesiveness is an inner portion of the outer peripheral portion. It is a bonding material of Claim 1 characterized by the above-mentioned.

According to a fifth aspect of the present invention, the area exhibiting adhesiveness or adhesiveness is dotted at the outer periphery along the shape of the display area, and the area exhibiting adhesiveness is between the points and the outer periphery. The bonding material according to claim 1, wherein the bonding material is a structure existing in an inner portion of the bonding material.

  The invention described in claim 6 is an optical element in which a substance having an optical effect is sandwiched between a pair of substrates, and an optical film laminated on the optical element. It is a display element characterized by being fixed and laminated | stacked using the bonding material of description.

  The invention according to claim 7 is an optical element in which a substance having an optical effect is sandwiched between a pair of substrates, and an optical film laminated on the optical element. A display element is manufactured by fixing and laminating using the bonding material described in 1. above.

  With the above configuration, the present invention has the following effects.

  In invention of Claim 1 thru | or 7, it becomes possible to make small the resistance force at the time of deforming an optical element by using a bonding material, and it is easy to use it by storing or carrying a display. Improve. This also means that the stress generated on the substrate of the optical element is reduced with deformation, so that the optical element is hardly separated from the substrate, and the mechanical durability of the display element can be enhanced. Similarly, it is possible to reduce the birefringence generated in these materials due to the fact that the coefficients relating to thermal expansion and hygroscopic expansion between the substrate of the optical element and the optical film differ depending on the materials.

It is sectional drawing of a display element. It is a figure which shows 1st or 2nd embodiment of the bonding material. It is a figure which shows 1st or 2nd embodiment of the bonding material. It is a figure which shows 1st or 2nd embodiment of the bonding material. It is a figure which shows 1st or 2nd embodiment of the bonding material. It is a figure which shows 1st or 2nd embodiment of the bonding material. It is a figure which shows 1st thru | or 3rd embodiment of the bonding material. It is a figure which shows 1st thru | or 4th embodiment of the bonding material. It is a figure which shows 1st thru | or 5th embodiment of the bonding material. It is a figure which shows the Example of manufacture of the polarizing plate with an adhesive material.

  Hereinafter, embodiments of the bonding material, the display element, and the manufacturing method of the display element of the present invention will be described. The embodiment of the present invention shows the most preferable mode of the present invention, and the present invention is not limited to this.

  The display element is obtained by bonding some optical film such as a polarizing plate to the optical element. When such a display element is deformed, in addition to the deformation stress of the optical element itself, a binding force is generated by laminating the optical film, and the display element is hardly deformed due to the effect. This restraining force is caused by the deformation stress of the optical film. By fixing the optical film to the optical element, the optical film is subjected to the same deformation as the substrate and generates stress. Since the distance from the neutral plane to the optical film when the display element is deformed is increased by fixation, a large stress is generated. If the fixed area is reduced, the amount of deformation and the generated stress are reduced accordingly, and if the fixed area is further dispersed, the deformation in the fixed area can be distributed to the deformation between the fixed areas, thereby minimizing the generated stress. it can. The flexibility of the display element can be evaluated by the flexural modulus of the display element. It can be said that the smaller the elastic modulus, the greater the flexibility. When the area of the display portion of the display element is 100, the display element having a fixed area smaller than 50 has a low flexural modulus, and the fixed area is 100, which is a normal bonding condition. In comparison, the flexural modulus is about ½, and the area of the fixed region and the flexural modulus of the display element are in a moderately proportional relationship. However, in a display element having an area of the fixed region larger than 50, the flexural modulus rapidly increases as the area of the fixed region increases, and the area of the fixed region, which is a normal bonding condition, approaches the flexural modulus of 100. .

  The positional accuracy with respect to the optical element is important for the optical film. In particular, the orientation of the optical axis of the optical film is required to have high accuracy in order to obtain an optical effect. Accordingly, in the present invention, it is a requirement of the invention to reduce the area of the fixed region, but a minimum area of the fixed region that maintains the positional accuracy of the optical film is necessary. Therefore, the area of the fixing region of the bonding material that facilitates the deformation of the display element and maintains the positional accuracy of the optical film, that is, the area of the region showing the adhesiveness or adhesiveness shown in FIGS. When the area of the region is 100, it is preferably 1.0 to 70.0, more preferably 3.0 to 40.0, and most preferably 5.0 to 30.0. Expressing this as the area ratio of the region showing adhesion, when the area of the display region is 100, it is preferably 30 to 99, more preferably 60 to 97, and most preferably 70 to 95.

  As the non-fixed region, an air layer may be provided between the optical element substrate and the optical film as in the prior art, but there are two interface reflections: the optical film / air interface and the air / substrate interface. Therefore, there is a problem that the luminance of the display element is lowered. Therefore, in the present invention, in order to enhance the adhesion between the optical film and the substrate in the non-fixed region and eliminate the air layer, a low viscoelastic material having a refractive index close to the refractive index of the optical film and the substrate is used. Insert between the film.

  There is a proposal in the prior art that a fluid substance is disposed between the optical film and the display area of the display element, which claims to be effective in improving the rework work. Further, in this proposal, a sticky / adhesive material is arranged so as to wrap the outside of the display element, and a non-display portion is surrounded by a frame shape outside the optical element. Such a frame-like non-display part not only goes against the recent design preference for a wide display part, but also the position of the adhesive / adhesive becomes the position of the frame, so the deformation of the display panel which is the subject of the present invention It cannot respond to the purpose of facilitating That is, in the prior art structure, since the optical film and the display element are indirectly fixed, the orientation of the two cannot be accurately maintained under deformation, and the flow material is deformed by deformation of the display element. May easily move through the element and accumulate in a biased manner, resulting in sagging of the optical film and deterioration of optical characteristics. In this invention, since a transparent adhesive / adhesive material is provided on the display unit, the area of the frame can be reduced, the orientation between the optical film and the display unit is accurately maintained, and the material has adhesiveness. And the deterioration of optical characteristics can be minimized.

[Bonding material]
(Composition of bonding material)
The bonding material of this embodiment is demonstrated based on FIG. FIG. 1 is a cross-sectional view of a display element.

  In the present invention, stickiness refers to the property of fixing to an adherend by a viscous force, such as the surface of a highly viscous liquid or gel solid, and adhesiveness is the property of fixing to the adherend as a solid or viscoelastic body. It is. The term “viscous / adhesive” in this specification refers to materials that exhibit tackiness or adhesion. Moreover, the area | region which shows adhesiveness or adhesiveness refers to the area | region tinged with such a property, and is formed with an adhesive agent. The adhesive strength of the adhesive / adhesive sandwiched between the adherends is preferably 200 g / 20 mm or more, and more preferably 1000 g / 20 mm or more.

  The adhesion described in the present invention refers to the property of maintaining contact between the substrate and the optical film, or between the optical films, and the ability to fix is extremely small unlike tackiness or adhesiveness. Examples of the low viscoelastic material exhibiting adhesion include a liquid or a viscoelastic body whose viscosity and / or elastic modulus is smaller than that of an adhesive or a cured adhesive. As a material showing adhesion in the present invention, the smaller the viscosity and / or elastic modulus, the smaller the stress generated when the display element is deformed, which is preferable. However, if the viscosity and / or elastic modulus is too small, or if the affinity with the adhesive / adhesive is poor, adhesive materials may leak out of the display element, and the optimal viscosity And there is a range of affinity.

  The viscosity is preferably from 0.01 to 5000 Pa · s, more preferably from 0.01 to 1000 Pa · s. The Young's modulus is preferably 100 to 0.001 kPa, and more preferably 10 to 0.001 kPa. When the contact angle of a material exhibiting adhesion on a sticky / adhesive material is used as a measure of affinity, the preferred affinity is that the contact angle is preferably 0 to 90 °, more preferably 0 to 60 °, and 0 -30 ° is most preferred.

  The bonding material 10 of this embodiment is a material for fixing the optical film 4 laminated on the optical element 3 in the display region, and bonding the optical element 3 and the optical film 4 laminated on the optical element 3 together. The display element 20 is manufactured by fixing and laminating using the material 10.

  The optical element 3 is obtained by sandwiching a substance 3b having an optical effect between a pair of substrates 3a and 3a, and a bonding material 10 includes a region 1 exhibiting adhesiveness or adhesiveness, and a region 2 exhibiting adhesiveness. Have The region 1 exhibiting adhesiveness or adhesiveness and the region 2 exhibiting adhesiveness can be configured as shown in FIGS. Further, as shown in FIG. 1, the region 2 showing adhesion may contact the optical film 4 (FIG. 1 (a)) or may contact the optical element 3 (FIG. 1 (b)). 4 and the optical element 3 may be contacted simultaneously (FIG. 1C). These configurations can be selected depending on the positional accuracy between the optical film 4 and the optical element 3 and the mechanical durability and flexibility of the display element 20 after the two are bonded. The structure of FIG. 1 (c) is the most flexible and soft structure, and then the order of FIG. 1 (a) and FIG. 1 (b). The structure with the highest positional accuracy and durability is shown in FIG. 1 (b), followed by FIG. 1 (a) and FIG. 1 (c) in this order. Moreover, since the structure of FIG.1 (b) and FIG.1 (c) can be set as the product of the form which added the bonding material to the optical film 4, handling becomes easy.

  In the first embodiment shown in FIG. 2, the distribution of the region 1 exhibiting adhesiveness or adhesiveness and the region 2 exhibiting adhesiveness has a sea-island structure. Here, “sea” (region 2 in FIG. 2) refers to a region having a continuous structure, and “island” (region 1 in FIG. 2) refers to an independent region surrounded by the continuous structure. As shown in FIG. 3, this structure can be an inverted structure in which the region showing tackiness or adhesiveness is “sea” and the region showing adhesion is “island”. In addition, the structure of FIG. 4 in which the “islands” are dotted, the structure of FIG. 5 in which the “islands” are rectangles parallel to the sides of the display elements, and the rectangular “islands” are inclined with respect to the sides of the display elements. The structure of FIG. 6 is also possible. In any case, a structure in which a region exhibiting adhesiveness or adhesiveness and a region exhibiting adhesiveness are reversed is possible.

  In the second embodiment shown in FIG. 7, the distribution of the region 1 exhibiting adhesiveness or adhesiveness and the region 2 exhibiting adhesiveness are both continuous structures. In the third embodiment shown in FIG. 8, the region 1 exhibiting adhesiveness or adhesiveness is an outer peripheral portion along the shape of the display region, and the region 2 exhibiting adhesiveness is an inner portion of the outer peripheral portion. . In the fourth embodiment shown in FIG. 9, the region 1 showing stickiness or adhesiveness is dotted at the outer periphery along the shape of the display region, and the region 2 showing adhesiveness is between the points from the outer periphery. It is a structure existing on the inner side.

  As a method of forming the region 1 exhibiting adhesiveness or adhesiveness and the region 2 exhibiting adhesiveness, for example, a low viscoelastic material exhibiting adhesiveness but low adhesiveness or adhesiveness is formed on a material exhibiting adhesiveness or adhesiveness. It is configured by forming. In this case, the adhesive strength of the region 2 showing the adhesion needs to be extremely small, but the influence of the adhesive strength of the adhesive / adhesive used for the base increases with time, and the adhesive strength of the region 2 increases. Tend. This is presumed that the influence of the adhesiveness increased because the material showing adhesion gradually penetrated into the adhesive / adhesive and the adhesive / adhesive appeared on the surface. In order to make the adhesive strength of the region exhibiting adhesiveness not change over time, the shape of the non-fixed region exhibiting adhesiveness does not have a uniform spread, and the dispersed form can reduce the change. The structures of FIGS. 2 to 7 are preferable to the structures of FIGS.

  That is, the structure in which the fixing region exhibiting adhesiveness or adhesiveness divides the non-fixing region exhibiting adhesiveness is preferable because the influence on the change in adhesive force is small. Although the adhesive strength of the non-fixed region shows a tendency to increase with time, it is smaller than the adhesive strength or adhesive force of the fixed region, and exhibits a large adhesive force that antagonizes the fixed region unless the non-fixed region takes a large area. Absent. For this reason, in the structure in which the fixed region divides the non-fixed region, the area of the non-fixed region is divided into small parts, and the adhesive force per one divided region is reduced, so even if the adhesive force changes. However, the effect is estimated to be small.

  When the fixing region showing adhesiveness or adhesiveness is made of an adhesive material, the adhesive material portion of the bonding material between the substrate and the optical film is cured by light or heat to become a viscoelastic body. Changes over time are unlikely to occur.

  It is also possible to utilize the effect that the adhesive force of the region showing the adhesion increases with time. For example, when you want to fix and use the display element in a deformed state, the flat display element is deformed flexibly when setting it to any deformed state, and the adhesive force gradually increases after setting Thus, it is possible to increase durability by making it difficult to peel off the optical film on the display element in a deformed state.

  The viscosity of the adhesive material has an effect on the phenomenon in which the adhesive strength of the region 2 increases with time, and the material having a higher viscosity tends to retain the initial adhesive strength. This is presumably because the viscosity of the adhesive material has a great influence on the speed at which the adhesive material penetrates into the sticky / adhesive material, and it becomes difficult to penetrate when the viscosity is large. Such a threshold value varies depending on the material, and is 0.1 Pa · S in a system using an acrylic material as an adhesive / adhesive and using silicone oil as an adhesive material, for example. That is, if it is 0.1 Pa · S or more, the adhesive material is less likely to penetrate into the adhesive / adhesive material, and the adhesive strength of the region showing the adhesiveness is not substantially changed.

  Preferable examples of the adhesive / adhesive include acrylic, rubber-based, polyester-based, silicone-based, and urethane-based adhesives, and it is particularly preferable to use an acrylic adhesive.

  Acrylic adhesives are known additions to polymers obtained by copolymerizing one or more alkyl acrylate monomers and acrylic monomers such as acrylic acid or monomers having a functional group other than acrylic. Add the agent. Such a copolymer imparts appropriate wettability and flexibility to the pressure-sensitive adhesive, and has a glass transition temperature of minus 10 ° C. or lower. Examples of the polymerization method include a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a suspension polymerization method, and various polymerization catalysts are used as necessary. The acrylic pressure-sensitive adhesive may be a thermal crosslinking type, or a photocrosslinking type using ultraviolet rays or electron beams.

  Adhesives include natural polymers such as glue and starch, semi-synthetic polymers such as cellulose acetate, polyvinyl acetate, polyvinyl chloride, epoxy resin, urethane resin, polychloroprene, acrylonitrile-butadiene copolymer (NBR) Synthetic polymers such as melamine resin, acrylic resin, ethylene-vinyl acetate copolymer, polyester, and polyamide may be used. These can be used as adhesives of various curing types such as room temperature curing, heat curing, or ultraviolet, electron beam or laser irradiation curing.

  Adhesive materials have extremely low fixing ability to adherends, and need to maintain good contact with the adherends. It is not preferable that the adhesive or adhesiveness is lost by intruding into the film. Further, it is not preferable that the optical film penetrates or the optical properties such as polarization characteristics and phase characteristics are affected by the penetration. Depending on the combination with adhesive and adhesive, specific materials include silicone compounds such as silicone oil, hydrocarbon compounds such as liquid paraffin, oils such as olive oil, higher alcohols such as 1-octanol, linoleic acid, etc. Higher fatty acids, organic acid ester compounds such as dibasic acid esters (diesters) and polyol esters, phosphoric acid esters, silicate esters, and other perfluoropolyethers such as Variel IEL Fluid (NOK Corporation) and chlorotrifluoro A material that is liquid at room temperature, such as a low polymer of ethylene, is preferred. Other materials that have a low possibility of leaking from the display element to the outside are materials with extremely low viscosity and elastic modulus among the above-mentioned adhesives / adhesives, and low viscosity and low elastic modulus by gently crosslinking liquid rubber. Diene-based, silicone-based, urethane-based, and polysulfide-based rubber materials, elastomers having a low elastic modulus, and the like can be used.

Further, it the amount of adhesion material forming on the material showing the tackiness or adhesive is preferably from ^{0.1μg / mm 2 ~200μg / mm 2} , a 1μg ^/ mm ² ~200μg ^/ mm 2 more preferably, and most preferably ^{3μg / mm 2 ~100μg / mm 2} . If the amount is too small, it is not possible to form a region that exhibits substantial adhesion, and if the amount is too large, when leaking to the outside from the display element, or when an optical film is bonded to an optical element, The low viscoelastic material is not preferable because it spreads to a region showing tackiness or adhesiveness, and the area of the fixed region is narrowed or disappears.

(Production method of bonding material)
The first method for producing a bonding material is to knead a visco / adhesive material and a low viscoelastic material that exhibits adhesion but does not exhibit tackiness or adhesion. For example, FIG. 2 to FIG. 4 and FIG. After forming the arbitrary structure shown, it is applied on a release film, and further laminated on the release film to form a bonding material.

  In the second production method of the bonding material, after laminating the adhesive / adhesive material with two release films, one release film is peeled off and bonded to the optical film. Next, the other release film is peeled off, and a low viscoelastic material that shows adhesiveness but does not show adhesiveness or adhesiveness is printed so as to have an arbitrary distribution shape as shown in FIGS. 2 to 9, for example. Alternatively, a pattern is applied and laminated again with a release film to obtain a bonding material on the optical film.

  In the third production method of the bonding material, after laminating the adhesive / adhesive material with two release films, one release film is peeled off and bonded to the optical film. Next, the other release film is peeled off and masked so that, for example, an adhesive or adhesive region having an arbitrary shape as shown in FIGS. 2 to 9 remains, and this shows adhesiveness but has adhesiveness or adhesiveness. After spraying, dipping, and applying a low viscoelastic material not shown, the release film used as a mask is peeled off and laminated again with another release film to obtain a bonding material on the optical film.

  In the fourth method for producing the bonding material, after laminating the adhesive / adhesive material with two release films, one release film is peeled off and bonded to the substrate of the optical element. Next, the other release film is peeled off, and a low viscoelastic material that shows adhesiveness but does not show adhesiveness or adhesiveness is printed so as to have an arbitrary distribution shape as shown in FIGS. 2 to 9, for example. Alternatively, a pattern is applied and laminated again with a release film to obtain a bonding material on the substrate.

  In the fifth production method of the bonding material, after the adhesive / adhesive material is laminated with two release films, one release film is peeled off and bonded to the substrate. Next, the other release film is peeled off and masked so that, for example, an adhesive or adhesive region having an arbitrary shape as shown in FIGS. 2 to 9 remains, and this shows adhesiveness but has adhesiveness or adhesiveness. After spraying, dipping, and applying a low viscoelastic material not shown, the release film used as a mask is peeled off and laminated again with another release film to obtain a bonding material on the substrate.

  The sixth production method of the bonding material is a low-viscoelastic material that exhibits adhesiveness but does not exhibit tackiness or adhesiveness on the release film, for example, any distribution shape as shown in FIGS. Print or apply a pattern. The release film is used to laminate a sticky / adhesive material to obtain a bonding material.

  A seventh method for producing a bonding material is to print or pattern a low-viscoelastic material that exhibits adhesion but does not exhibit tackiness or adhesiveness, and an arbitrary shape of adhesive / adhesive on a release film. Apply. Lamination is performed again with another release film to obtain a bonding material. If the bonding material obtained by this method is used, it is possible to obtain a display element in which a low viscoelastic material and a visco / adhesive material are bonded to each other in contact with both the substrate and the optical film.

  Using the bonding material obtained by any method, the optical film and the optical element are bonded to obtain the display element of the present invention.

(Configuration and manufacturing of display element)
In the display element 20 of this embodiment, an optical element 3 having a substance 3b having an optical effect sandwiched between a pair of substrates 3a and 3a and an optical film 4 laminated on the optical element 3 are bonded to a bonding material 10. It is manufactured by fixing and stacking using

"substrate"
As the substrate 3a of the optical element, a polymer film excellent in heat resistance such as polyimide or polysulfone, a polymer film reinforced with an inorganic material, or a composite substrate reinforced by bonding a polymer film to glass is used. This substrate is provided with a transparent electrode made of ITO or the like and a connection terminal. Of course, glass may be used, and glass that can be bent flexibly by reducing the thickness or strengthening the material is even better.

"Substance with optical effect"
As the substance having an optical effect, a substance that operates by electricity is used. By using the substance having the optical effect, the optical element can be, for example, a liquid crystal display element, an EL element, a microcapsule element, an electropowder fluid element, an electrowetting element, an electric element. There are electrophoretic elements. Examples of the display element using such an optical element include a liquid crystal display device, an organic EL display device, and an electrophoretic display device. The liquid crystal display device has features such as power saving, light weight, thinness, and the like. As a general liquid crystal display device, an incident side polarizing plate, an output side polarizing plate substrate, and a liquid crystal in a portion that is operated by electricity Those having the following are typical. Compared with a liquid crystal display device, an organic EL display device has many advantageous characteristics as a display such as a high response speed, a wide viewing angle, good visibility unique to a self-luminous element, and a wide temperature range that can be driven. This organic EL display device has a configuration in which a lower electrode, an organic EL layer that is operated by a substance having an optical effect, and an upper electrode are stacked in each pixel formed on the substrate from the substrate side. Light from the organic EL that emits light when an electric current is passed through the EL layer is recognized through at least one of the electrodes (translucent conductive film). As an electrophoretic display device, a microcapsule electrophoretic method has been put to practical use as one of display devices utilizing an electrophoretic phenomenon. In this type of display device, positively and negatively charged white particles and black particles are placed in a microcapsule that is electrically operated and filled with a transparent solvent, and each particle is pulled up to the display surface by applying an external voltage. To form an image.

"Optical film"
The optical film 4 is used for the purpose of protecting or enhancing the optical effect, and is a film such as a protective film, a polarizing plate, a retardation film, a light guide plate, or a diffusion plate.

[Example]
Example 1
Into a solution (solid content 15%) containing an acrylic polymer having a weight average molecular weight of 1 million consisting of a copolymer of butyl acrylate: acrylic acid = 95: 5 (weight ratio), with respect to 100 parts of the polymer solid content, 0.2 part of Coronate L (manufactured by Nippon Polyurethane) was added to prepare an adhesive solution. This pressure-sensitive adhesive solution was applied onto a release film (A) in which a thermosetting silicone resin release agent was applied on one side of a 25 μm thick polyester film so that the thickness of the pressure-sensitive adhesive when dried was 25 μm. The work was dried. Further, an adhesive film (C) was obtained by laminating another release film (B) which was produced in substantially the same manner as the release film (A) but whose release property was changed. The adhesive strength of this adhesive was 1100 g / 20 mm with respect to the polarizing plate and substrate used below.

  The pressure-sensitive adhesive film (C) produced above was cut out to 80 × 60 mm, and one release film (B) was peeled off and bonded to a polarizing film with a thickness of 100 μm to obtain a polarizing plate (D1) with a pressure-sensitive adhesive ( FIG. 10 (a)). The release film (A) is peeled off from the polarizing plate (D1). Instead, the release film obtained in the same manner as the release film (A) is perforated with a predetermined pattern shown in FIG. 10 (b). It was set as the open release film (E), and it bonded so that the center position might match the center position of a polarizing plate (FIG.10 (c)).

As a low-viscoelastic material that shows adhesiveness but does not show adhesiveness or adhesiveness from the release film (E) with the laminated structure of FIG. 10 (c), silicone (manufactured by Shin-Etsu Silicone Co., Ltd., KF96-50CS, Viscosity of 0.05 Pa · s) was sprayed, and a predetermined amount was applied. Thereafter, the release film (E) was peeled off, and a bonding material (F) composed of a region showing tackiness or adhesiveness and a region showing adhesion (region where silicone was adhered) was formed on one side. A polarizing plate (G) was obtained (FIG. 10 (d)). When the release film (E) is peeled off from the polarizing plate (G) with the bonding material, 20 adhesive material regions of 6 × 5 mm remain around the surface at intervals of 6 mm, and the area of the entire polarizing plate is 100 The ratio occupied by the area of the region showing adhesion (area ratio of the adhesion material region) was 87%, and 13% was the region showing adhesiveness. Here, a polarizing plate with a bonding material obtained by setting the predetermined amount of silicone to 1 μg / mm ² was G-F1, and 5 μg / mm ² was obtained as G-F2 and obtained as 7 μg / mm ² . This is G-F3.

(Example 2)
The substrate is a polymer film obtained by impregnating a glass cloth with an acrylic monomer and curing. A transparent electrode or connection terminal pattern made of ITO or the like is formed on the substrate by sputtering, and then patterned by photolithography. On the surface of the transparent electrode, a polyimide alignment film or the like is formed in advance by a printing method and subjected to an alignment treatment. Further, a conductive material is formed on the substrate. The conductive material is made of carbon paste and is formed on the electrical connection portion between the connection terminal pattern and the signal line electrode by a dispenser.

  Thereafter, a sealing material for sealing a substance having an optical effect, which is made of an ultraviolet curable resin, a resin curable by a combination of ultraviolet rays and heat, or a thermosetting resin such as an acrylic resin or an epoxy resin on the substrate, A rectangular frame is formed using a coating tool such as a dispenser.

  Next, a liquid crystal material is supplied to the substrate by a dropping injection method. That is, a liquid crystal material is dropped inside a rectangular frame-shaped sealing material formed on the surface of the substrate.

  A color filter, a spacer, and a conductive film are formed on another substrate by photolithography. Thereafter, this substrate is superposed under vacuum on the substrate on which the liquid crystal has been dropped. When a liquid crystal panel composed of two superimposed substrates is taken out under atmospheric pressure, the two substrates are brought into close contact with each other due to a pressure difference.

  Subsequently, the sealing material was cured by ultraviolet irradiation or heating to obtain a liquid crystal display (display unit size 80 × 60 mm). A polarizing plate, G-F1, G-F2, and G-F3, each having the bonding material (F) obtained in Example 1 formed on one side, are bonded to both surfaces of the obtained liquid crystal panel (H). , Liquid crystal displays, H-F1, H-F2, and H-F3 were obtained. The bonding material was transparent and did not show birefringence, and even if there was a bonding material in the display portion, the region showing tackiness or adhesiveness and the region showing adhesion did not give different visibility. Therefore, the bonding material did not narrow the area of the display area.

  The liquid crystal displays (H-F1 to H-F3) were evaluated by a three-point bending test to obtain the elastic modulus of the entire liquid crystal display. The results are summarized in Table-1.

The three-point bending test was carried out by placing a liquid crystal display as a test piece between two edges serving as fulcrums and pressing the center with a pressure nose. The distance between the edges was 40 mm, the pressing nose was pushed in at a speed of 100 mm / min, and the tip of the pressing nose was pushed down 10 mm from the edge, and the bending elastic modulus was obtained from the initial straight line portion of the obtained unloading curve.

(Comparative Example 1)
On the other hand, the polarizing plate (D) with the adhesive material of Example 1 was bonded to both surfaces of the liquid crystal panel obtained in the same manner as in Example 2 to obtain a liquid crystal display (HD). A flexural modulus was obtained in the same manner as in Example 1.

From Table-1, the liquid crystal display (G-) produced in Example 1 compared with the case where the whole polarizing plate which is a normal bonding method like the comparative example 1 was bonded to the whole liquid crystal display (HD). The elastic moduli of F1 to F3) are small, indicating that the flexibility has increased.

  In addition, the liquid crystal display (HD) produced under the conditions of Comparative Example 1 was found to have some liquid crystal leakage due to partial peeling of the seal after the bending test, but the liquid crystal display of Example 1 (G-F1). No liquid crystal leakage was observed in -F3). From this result, it can be seen that the increased flexibility of the liquid crystal display also improved the durability against deformation of the display.

  In any of the examples, the bonding material is transparent and does not exhibit birefringence, and even if there is a bonding material in the display portion, the region showing adhesiveness or adhesiveness is different from the region showing adhesion. Therefore, the bonding material did not narrow the area of the display region, and a uniform display was shown.

(Example 3)
As performed in Example 1, the area ratio between the region showing adhesion and the region showing adhesiveness was changed using a release film having holes formed in advance in a predetermined pattern. As shown in FIG. 10D, a pattern in which a plurality of 6 × 5 mm adhesive material regions remain on the outer periphery of the polarizing plate is obtained, and the polarizing plate (G) is obtained by changing the interval between the adhesive material regions. A liquid crystal display (H) was produced in the same manner as in Example 2 using G). Silicone (manufactured by Shin-Etsu Silicone Co., Ltd., KF96-50CS, viscosity of 0.05 Pa · s) is used as a low viscoelastic material that exhibits adhesion but does not exhibit tackiness or adhesiveness, and its adhesion amount is 5 μg / mm ² It sprayed so that it might become. A liquid crystal display provided with a pattern so that 28 6 × 5 mm adhesive material regions remain at the outer peripheral portion at 3 mm intervals is H-F4, and a pattern such that 18 6 × 5 mm adhesive material regions remain at the outer peripheral portion at 9 mm intervals. A liquid crystal display provided with a pattern was H-F5, and a liquid crystal display provided with a pattern so that 12 pieces of 6 × 5 mm adhesive material regions remained at 15 mm intervals on the outer periphery was designated H-F6. Further, the adhesive material region is provided in the outer peripheral portion as shown in FIG. 8, the inner side is the adhesive material region, and the area of the display region is 100, so that the area of the adhesive material region is 40. A liquid crystal panel was produced in the same manner as in Example 2 (H-F7).

  In the same manner as in Example 2, the liquid crystal displays (H-F4 to H-F7) were evaluated by a three-point bending test to obtain the elastic modulus, and are shown in Table-2.

As shown in Table-2, compared with the case where the entire polarizing plate, which is a normal bonding method of Comparative Example 1, is bonded to the entire liquid crystal display (HD of Comparative Example 1), the area ratio of the adhesive material region The larger the value is, the smaller the elastic modulus of the liquid crystal display is, so that it can be a flexible display.

  After the bending test, in the liquid crystal display (H-F4 to F7) of Example 3, there was no liquid crystal leakage that caused a part of the seal to peel off. From this result, it can be seen that the increased flexibility of the liquid crystal display also improved the durability against deformation of the display.

  Further, in any of the examples, the bonding material is transparent and does not exhibit birefringence, and even if there is a bonding material in the display portion, the region showing adhesiveness or adhesiveness is different from the region showing adhesion. Visibility was not given, and thus the area of the display area was not reduced by the bonding material, and a uniform display was shown.

Example 4
The pattern shown in FIGS. 2 to 9 on a release film (A) obtained by applying a thermosetting silicone resin release agent on one side of a polyester film having a thickness of 25 μm, using the flexographic printing machine. Silicone (Shin-Etsu Silicone Co., Ltd., KF96-50CS, viscosity 0.05Pa · s) is printed as a low-viscosity material that shows but does not exhibit tackiness or adhesiveness, and has a release film with a pattern (AE and BE) Got. The flexographic plate used was designed as follows. Silicone can be printed with the pattern of the region showing adhesion in FIGS. 2 to 9, and when the area of the display region is 100, the area for printing silicone (area of the region showing adhesion) is 87. The transfer amount was designed to be 10 μg / mm ² .

  Into a solution (solid content 15%) containing an acrylic polymer having a weight average molecular weight of 1 million consisting of a copolymer of butyl acrylate: acrylic acid = 95: 5 (weight ratio), with respect to 100 parts of the polymer solid content, 0.2 part of Coronate L (manufactured by Nippon Polyurethane) was added to prepare an adhesive solution. This pressure-sensitive adhesive solution was applied and dried on a patterned release film (AE) so that the thickness of the pressure-sensitive adhesive when dried was 25 μm. Then, the release film with pattern (BE) was laminated and the bonding material film (FE) was obtained.

The bonding material film (FE) produced above was cut into 80 × 60 mm, the single-sided release film (BE) was peeled off, and bonded to both surfaces of the liquid crystal panel (H) obtained in Example 2. The amount of silicone remaining on the surface of the bonding material after peeling off the release film (BE) was about 5 μg / mm ² . The release film (AE) remaining from the liquid crystal panel with the bonding material film was peeled off from both surfaces, and a polarizing film having a thickness of 100 μm was bonded to both surfaces. The amount of silicone remaining on the surface of the bonding material after peeling off the release film (AE) was about 5 μg / mm ² . Let the liquid crystal displays produced using the bonding material which printed the silicone by the pattern of FIG. 2 thru | or FIG. 9 be HF-2 to HF-9, respectively.

  A liquid crystal display obtained under exactly the same conditions as HF-4 except that silicone having a viscosity of 0.3 Pa · s (manufactured by Shin-Etsu Silicone Co., Ltd., KF96-300CS) is used is designated as HF-10.

  A three-point bending test was carried out in the same manner as in Example 2, and the flexural modulus after 10 days and after 30 days was measured immediately after the polarizing film was bonded to the liquid crystal display. The results are shown in Table-3.

As shown in Table-3, compared with the case where the entire surface of the polarizing plate, which is a normal bonding method of Comparative Example 1, is bonded to the entire surface of the liquid crystal display (HD), an example in which a region showing adhesion is provided. The liquid crystal display 4 has a small elastic modulus, and can be a flexible display. Also, the bending elastic modulus is small overall, and this is considered to be caused by the fact that the region showing adhesion as in this example is in contact with both surfaces of the substrate and the polarizing plate. The flexural modulus increases with time, but reaches an equilibrium value in about 10 days, and the value is smaller than the HD of Comparative Example 1.

  After the bending test, in the liquid crystal display of Example 4 (HF-2 to HF-10), no part of the seal peeled off and liquid crystal leakage was observed. From this result, it can be seen that the increased flexibility of the liquid crystal display also improved the durability against deformation of the display.

  Further, in any of the examples, the bonding material is transparent and does not exhibit birefringence, and even if there is a bonding material in the display portion, the region showing adhesiveness or adhesiveness is different from the region showing adhesion. Visibility was not given, and thus the area of the display area was not reduced by the bonding material, and a uniform display was shown.

(Example 5)
Silicone gel (Opto Alpha Gel N100UK, Taika Co., Ltd.) with both sides protected by a release film as an adhesive is cut into 80x60mm, peeled off one release film and bonded to a polarizing film with a thickness of 100μm. A polarizing plate (D2) with a material was obtained. The other release film of the silicone gel is peeled off from the polarizing plate (D2), and instead, the release film obtained in the same manner as in Example 1 is perforated with a predetermined pattern shown in FIG. 10 (a). The release film (E) was laminated so that the center position thereof matched the center position of the polarizing plate. The adhesive strength of this adhesive was 4000 g / 20 mm with respect to the polarizing plate and substrate used below.

Silicone (Shin-Etsu Silicone Co., Ltd., KF96-50CS), liquid paraffin, 1-octanol is shown as a low-viscosity material that shows adhesion but does not show tackiness or adhesion from the release film (E) of this polarizing plate. Then, linoleic acid and olive oil were sprayed and applied to 5 μg / mm ² . Thereafter, the release film (E) was peeled off to obtain a polarizing plate (GK) in which a bonding material (K) composed of a region showing tackiness or adhesiveness and a region showing adhesion was formed on one side. . On the surface of the polarizing plate with a bonding material (GK) from which the release film (E) was peeled, 20 adhesive material regions of 6 × 5 mm remained at an interval of 6 mm, and the area of the entire polarizing plate was 100. The ratio of the area of the region showing the adhesion sometimes (area ratio of the adhesion region) was 87%, and 13% was the region showing the adhesiveness. Here, GK1 to GK5 are polarizing plates with bonding materials prepared using silicone, liquid paraffin, 1-octanol, linoleic acid, and olive oil as low viscoelastic materials that exhibit adhesion but do not exhibit tackiness or adhesion. It was.

  The polarizing film with a bonding material (GK) was bonded to both surfaces of the liquid crystal panel (H) obtained in Example 2, and designated as H-GK1 to H-GK5, respectively.

  A three-point bending test was performed in the same manner as in Example 2 to measure the flexural modulus of the liquid crystal display. Moreover, the contact angle between the used visco / adhesive and the low viscoelastic material which shows adhesion but does not show tackiness or adhesion was measured. The results are shown in Table-4.

As shown in Table-4, a liquid crystal display provided with a region showing adhesion as compared to the case where the entire polarizing plate surface, which is a normal bonding method of Comparative Example 1, is bonded to the entire liquid crystal display surface (HD). The elastic modulus is small, and a display with high flexibility can be obtained. When a low viscoelastic material that exhibits adhesion but does not exhibit stickiness or adhesion has a high affinity with the visco-adhesive and substrate, that is, a material with a small contact angle, leakage to the outside of the liquid crystal display is small. Moreover, there was little invasion of bubbles.

  Among these, H-GK1 showed a tendency for the part of the adhesive / adhesive material to swell over time. Moreover, the adhesive force of the area | region which shows adhesiveness or adhesiveness of H-GK4 fell gradually.

  After the bending test, in the liquid crystal display of Example 5, a part of the seal peeled off and liquid crystal leakage was not observed. From this result, it can be seen that the increased flexibility of the liquid crystal display also improved the durability against deformation of the display.

  Further, in any of the examples, the bonding material is transparent and does not exhibit birefringence, and even if there is a bonding material in the display portion, the region showing adhesiveness or adhesiveness is different from the region showing adhesion. Visibility was not given, and thus the area of the display area was not reduced by the bonding material, and a uniform display was shown.

  The present invention is applicable to a bonding material for bonding an optical film to an optical element sandwiching a substance having an optical effect such as a liquid crystal layer or an organic EL layer, a display element, and a method for manufacturing the display element. And the pair of substrates sandwiching the substance having an optical effect is prevented from peeling off or floating, and at the same time, it contributes to a narrow frame of the display element.

DESCRIPTION OF SYMBOLS 1 Area | region which shows adhesiveness or adhesiveness 2 Area | region 3 which shows adhesiveness Optical element 3a A pair of board | substrate 3b Substance which has an optical effect 4 Optical film 10 Bonding material 20 Display element

Claims (7)

It is a bonding material that fixes the optical film to be laminated on the optical element within the display area,
A bonding material comprising a region exhibiting adhesiveness or adhesiveness and a region exhibiting adhesiveness.   The bonding material according to claim 1, wherein a distribution between the region exhibiting adhesiveness or adhesiveness and the region exhibiting adhesiveness has a sea-island structure.   2. The bonding material according to claim 1, wherein the distribution of the region exhibiting adhesiveness or adhesiveness and the region exhibiting the adhesiveness are both continuous structures.   2. The structure according to claim 1, wherein the region exhibiting adhesiveness or adhesiveness is an outer peripheral portion along a shape of the display region, and the region exhibiting adhesiveness is an inner portion of the outer peripheral portion. The bonding material described. The area showing the adhesiveness or adhesiveness is dotted in the outer periphery along the shape of the display area,
The bonding material according to claim 1, wherein the adhesive region has a structure in which the region between the points is present on the inner side of the outer peripheral portion. An optical element sandwiching a substance having an optical effect between a pair of substrates;
An optical film laminated on the optical element,
A display element, which is fixed and laminated using the bonding material according to any one of claims 1 to 6. An optical element sandwiching a substance having an optical effect between a pair of substrates;
An optical film laminated on the optical element,
A display element is manufactured by fixing and laminating using the bonding material according to any one of claims 1 to 6, and manufacturing a display element.