WO2003083635A1 - Image display unit with touch panel - Google Patents

Abstract

An image display unit with touch panel comprising a touch panel portion, the touch panel portion comprising an upper substrate, a lower substrate arranged opposite to the upper substrate and transparent electrodes formed on facing surfaces of the substrates, and a display panel portion, the lower substrate of the touch panel portion and a front surface portion of the display panel portion bonded to each other by means of a pressure sensitive adhesive layer, wherein the upper substrate and lower substrate of the touch panel portion are both constituted of a polymer film and wherein the pressure sensitive adhesive layer is constituted of a pressure sensitive adhesive comprising as a base polymer an acrylic polymer whose function group concentration is 5 × 10-4 mol/g or less. The image display unit with touch panel ensures excellent display quality and, even when, for example, bonding failure occurs, the display panel can be easily reutilized.

Description

 Description Image display device with touch panel

 The present invention relates to an image display device with a touch panel having a touch panel as an input device on a display panel. Technology background

 A liquid crystal display device (hereinafter referred to as an LCD), which is generally used as a display panel, is disposed on the viewer's front side and has a first transparent substrate having a transparent electrode on the inside, and a transparent electrode on the viewer's back side. A liquid crystal cell including a second transparent substrate having a liquid crystal layer sandwiched between the transparent substrates, and further configured by combining a polarizing plate, a retardation plate, a reflection plate, and the like with the liquid crystal cell. ing.

 The touch panel as an input device generally consists of a polymer film (upper substrate) placed on the upper side (front side of the observer) and a glass (lower substrate) placed on the lower side (back side of the observer). ) Are arranged facing each other and a transparent electrode is formed inside each of them. With this configuration, by pressing the panel surface with a finger or a pen or the like from above and bringing the opposing transparent electrodes into contact with each other, the position can be detected based on the flow of current at the contact portion. A touch panel-equipped liquid crystal display device is constructed by stacking a touch panel on the LCD as described above. Thus, data can be input by operating the touch panel while viewing the information displayed on the LCD screen.

However, between the touch panel and the LCD, that is, between the glass (lower substrate) of the touch panel and the front surface of the LCD, both are integrally formed in a state where a gap is provided. As a result, there has been a problem that interface reflection occurs and display quality deteriorates. In addition, air bubbles and foreign matter are mixed in the voids, and there is a problem that display quality is degraded due to occurrence of floating. In addition, when the touch panel and the LCD are adhered to each other by the adhesive layer, in addition to the above-mentioned problems, when the replacement is required due to adhesion mistakes such as foreign matter inclusion or damage, peeling operation is required. It takes a lot of time and labor for the business, and there is also a problem that the adhesive remains on the LCD and cannot be reused.

 The present invention relates to an image display device with a touch panel in which the interface between the display panel and the touch panel is brought into close contact with each other via an adhesive layer, and has an excellent display quality, and can easily be used even when an adhesion error or the like occurs. Another object of the present invention is to provide a reusable image display device with a touch panel. Disclosure of the invention

 The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that the above object can be achieved by an image display device with a touch panel described below, and have completed the present invention.

That is, the present invention includes: a touch panel portion having an upper substrate, a lower substrate disposed to face the upper substrate, a transparent electrode formed on a facing surface of each of the substrates, and a display panel portion. In an image display device with a touch panel in which the lower substrate of the touch panel portion and the front surface of the display panel portion are in close contact with each other via an adhesive layer, both the upper substrate and the lower substrate of the touch panel portion are made of a polymer film, and The present invention relates to an image display device with a touch panel, wherein the layer is formed of an adhesive containing a acryl-based polymer having a functional group concentration of 5 × 10 to ⁴ mol Zg or less as a base polymer.

 In the present invention, the display panel portion and the touch panel portion are brought into close contact with each other via the adhesive layer.

Since unnecessary interfaces are eliminated, unnecessary reflection is eliminated and optical characteristics can be obtained. In addition, polymer films are used for both the upper and lower substrates of the touch panel. The use of a high molecular film makes the touch panel itself flexible and difficult to break.

In addition, when the display panel and the touch panel are brought into close contact with each other with the adhesive layer, the adhesion can be easily made without causing appearance problems such as air bubbles and floating on the surface. Moreover, the pressure-sensitive adhesive that forms adhesive layer as base polymer, the functional group concentration contains Akuriru polymer below 5 X 1 0- ⁴ mol Z g. By using such an acrylic polymer, an image display device with a touch panel having good display quality can be obtained, and the display panel can be easily reused even when an adhesion error or the like occurs. Especially the adhesive The layer has a good property of preventing bubbles and peeling before and after heat and humidification (moisture and heat resistance), and a property of maintaining optical performance such as transmittance and retardation value (optical function maintaining property).

The concentration of the functional group is 5 × from the stable adhesion characteristics between the touch panel portion and the display panel portion, the display quality, and the leakiness that allows the display panel to be easily reused in the event of an adhesion error or the like. 10_ ⁴ mol Zg or less. The functional group concentration, 3 X 1 0- ⁴ molar / g or less, more Shi preferred not more than 1 X 10- ⁴ mole / g les. In order to obtain stable adhesive properties, functional group concentration is good preferable to the ¹ X 1 ο_ β mole Zg above. The concentration of the functional group (mol Zg) is defined as {weight of the functional group-containing copolymerizing monomer (g) + molecular weight of the functional group-containing copolymerizing monomer (g / mol)} ÷ { The weight was calculated from the weight of the copolymerizable monomer containing no functional group (g) + the weight of the copolymerizable monomer containing a functional group (g)}. The functional group concentration (molar Zg) can be quantified using analytical equipment such as NMR and IR.

 In the image display device with a touch panel, the functional group of the ataryl polymer may be at least one selected from a carboxyl group, a hydroxyl group, an epoxy group, an amide group, an imide group, a sulfonic acid group, and a phosphoric acid group. Preferably, there is. In the image display device with a touch panel, when the interface between the display panel portion and the adhesive layer is A, and the interface between the adhesive layer and the touch panel portion is B, the peel adhesion at the interface satisfies A <B, and It is preferable that the 90-degree peel adhesion of A is 1 to 6 N / 2 Omm.

 By setting the peeling adhesive force of the interfaces A and B to A <B, when the touch panel portion was peeled off from the display panel portion, no adhesive layer remained on the display panel portion, and the adhesive layer adhered to the touch panel portion. In this state, the touch panel can be easily peeled off. As a result, the reworking workability in the event of a bonding error or the like is improved, and the reuse efficiency of the display panel is improved. Further, from the viewpoint of the stable adhesive property between the touch panel portion and the display panel portion, the 90 ° peel adhesive strength at the interface A is preferably 1 NZ 2 Omm or more, and more preferably 2 NZ 2 Omm or more. On the other hand, from the viewpoint of reworkability, it is preferably 6 NZ 2 Omm or less, more preferably 5 NZ 20 mm or less. Also 9

By setting the 0 degree peeling adhesive force in the above range, it is used at the time of touch panel input. Displacement of the adhesive layer due to local stress on the pressure-sensitive adhesive layer can be prevented. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is a schematic diagram showing a configuration of a liquid crystal display device with a touch panel. BEST MODE FOR CARRYING OUT THE INVENTION

 A preferred embodiment of an image display device with a touch panel according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of an image display device with a touch panel. In FIG. 1, the upper side corresponds to the observer side. The configuration shown here is merely an example, and the present invention is not limited to the configuration shown in FIG. FIG. 1 is for explaining the layer structure, and the dimensional relationship is exaggerated.

 The image display device with a touch panel in FIG. 1 includes a touch panel section 1 and a display panel section 2, both of which are integrated. The touch panel section 1 has an upper substrate 11 located on the viewer's front side, and a lower substrate 12 arranged opposite to the upper substrate and located on the viewer's back side.

 Both the upper substrate 11 and the lower substrate 12 are polymer films. As the polymer film, a transparent substrate can be used without any particular limitation. Examples of the material include cellulosic resins such as polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate resins, polyarylate resins, polyether sulfone resins, diacetyl cellulose, and triacetyl cellulose. And norbornene-based resins, olefin-based resins such as polyethylene and polypropylene, polyamide-based resins, polychlorinated butyl-based resins, and polystyrene-based resins. Examples of the polymer film include a material obtained by extruding the above material into a sheet by melt extrusion or a solution casting method, or a uniaxially or biaxially stretched material. Note that the upper substrate 11 and the lower substrate 12 can also be formed of a composite film in which the above-mentioned polymer film and polymer film are bonded.

On the outer surface of the upper substrate 11, a hard coat layer (or anti-glare layer) 14 can be formed as shown in FIG. The hard coat layer 14 is not particularly limited, but includes, for example, a melanin resin, a urethane resin, an alkyd resin, It can be performed by a method of applying a hard resin such as an acrylic resin, a silicon resin, or an epoxy resin and performing a heat curing treatment or an ultraviolet curing treatment. At the time of hard coat treatment, a hard resin such as acrylic urethane resin is blended with silicon and the like to roughen the surface, and at the same time, an anti-glare layer that can prevent reflection by mirror action when used as a touch panel is used. It can also be formed.

A transparent electrode 13 is formed inside the upper substrate 11 and the lower substrate 12. The transparent electrodes 13 are arranged to face each other. In addition, a dot spacer 15 is provided between the transparent electrodes 13 to keep the interval. For the formation of the transparent electrode 13, for example, various thin film forming methods such as a vacuum deposition method, a sputtering method, an ion plating method, a spray pyrolysis method, a chemical plating method, an electric plating method or a combination thereof are appropriately selected. can do. As a material for forming the transparent electrode 13, a material that can form a transparent conductive film is appropriately selected and used. Preferably, for example, metals such as gold, silver, platinum, palladium, copper, aluminum, nickel, chromium, titanium, iron, covanolate, tin and alloys thereof, and indium oxide, tin oxide, titanium oxide, and acid Metal oxides composed of a chemical doping and a mixture thereof, and other metal compounds composed of copper iodide and the like are used. The thickness of the transparent electrode 13 can be appropriately determined according to the purpose of use. For example, as the electrode plate of the resistive film type Tatsuchipaneru, generally is that the 1 0 ³ Ω / mouth following surface resistance preferable. Such a surface resistance is generally set to a thickness of about 30 to 600 people in the case of a metal-based transparent conductive film, and to a thickness of about 80 to 500 OA in the case of a metal-oxide-based transparent conductive film. Can be achieved.

 When the transparent electrode 13 is attached, corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputter etching treatment, undercoat treatment, Bombard discharge treatment, electron beam irradiation are applied to the finolem surfaces of the upper substrate 11 and the lower substrate 12. Appropriate treatments such as irradiation, chemical conversion, oxidation, and flame can be performed to increase the adhesion to the transparent electrode 13.

The dot spacer is provided to prevent contact between the transparent electrode of the upper substrate and the transparent electrode of the lower substrate when the touch panel is not operated, and is usually formed in an arbitrary shape on the surface of the transparent electrode of the lower substrate. For example, a dot spacer prints an ultraviolet-curable ink on the surface of a transparent electrode using a silk screen and irradiates it with ultraviolet light. Can be formed.

 As the display panel section 2, various display panels conventionally used can be used. In FIG. 2, a polarizing film 22 is attached to both sides of the liquid crystal cell 21. The liquid crystal cell 21 has flexibility and can be easily applied to a curved surface, a large area surface, or the like. Examples of the cell include an active matrix driving type represented by a thin film transistor type and a simple matrix driving type represented by a twisted nematic type and a super twisted nematic type. A liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an optical element, and an illumination system as necessary, and incorporating a drive circuit. When forming a liquid crystal display device, for example, appropriate components such as a diffusion plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, and a backlight are placed at appropriate positions in one or two layers. More than one layer can be arranged.

 The polarizing film (polarizer) is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, an ethylene / butyl acetate copolymer-based partially saponified film, and an iodine dichroic dye. And a uniaxially stretched film obtained by adsorbing the dichroic substance described above, and a polyene-based oriented film such as a dehydrated product of polybutyl alcohol and a dehydrochlorinated product of polychlorinated vinyl. Among these, a polarizer composed of a polybiol alcohol-based film and a dichroic substance such as iodine is preferred. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

A uniaxially-stretched polarizer obtained by dyeing a polybutyl alcohol-based film with iodine is produced, for example, by dyeing polybutyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. be able to. If necessary, it can be immersed in an aqueous solution of potassium borate boride or the like. If necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, it is possible to clean the surface of the polyvinyl alcohol-based film and the anti-blocking agent. By swelling the rucol-based film, there is also an effect of preventing unevenness such as uneven dyeing. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

 The polarizer is usually provided with a transparent protective film on one or both sides and used as a polarizing plate. It is preferable that the transparent protective film is excellent in transparency, mechanical strength, heat stability, moisture shielding property, isotropy and the like.

 As a material for forming a transparent protective film provided on one or both surfaces of the polarizer, a material having excellent transparency, mechanical strength, heat stability, moisture shielding property, isotropy and the like is preferable. For example, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as diacetyl cellulose / triacetyl cellulose, acrylic resins such as polymethyl methacrylate, polystyrene / acrylonitrile / styrene copolymer (AS resin) And styrene resins and polycarbonate resins. Also, amide resins such as polyethylene, polypropylene, polyolefin having a cyclo- or norpolenene structure, polyolefin resins such as ethylene / propylene copolymer, butyl chloride resins, nylon-based aromatic polyamides, and imido resins. Resin, sulfone resin, polyether sulfone resin, polyether ether ketone resin, polyphenylene sulfide resin, butyl alcohol resin, chloroidene vinylidene resin, butyl butyral resin, arylate resin, poly An oxymethylene-based resin, an epoxy-based resin, or a blend of the above-mentioned resins is also an example of the resin that forms the transparent protective film. The transparent protective film can be formed as a cured layer of a thermosetting resin such as an acrylic resin, a urethane resin, an acrylic urethane resin, an epoxy resin, or a silicone resin, or an ultraviolet curable resin. Of these, cellulosic resins are preferred. The thickness of the transparent protective film is not particularly limited, but is generally 500 μηι or less,

1 to 300 μπι is preferred. Particularly, the thickness is preferably 5 to 200 μm.

In addition, it is preferable that the transparent protective film is as colored as possible. Therefore, R th = [(nx + ny) / 2-nz] d (where nx and ny are the main refractive indices in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness. Ah A protective film having a retardation value in the film thickness direction of -90 nm to 1775 nm represented by the following formula is preferably used. By using a material with a retardation value (R th) in the thickness direction of from 90 to 1775 nm, the coloring (optical coloring) of the polarizing plate caused by the transparent protective film is almost eliminated. can do. The retardation value (Rth) in the thickness direction is more preferably 180 nm to 160 nm, particularly preferably 170 nm to 45 nm.

 As the transparent protective film, a cellulosic resin such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. Particularly, triacetyl cellulose film is preferable. When transparent protective films are provided on both sides of the polarizer, a protective film made of the same resin material may be used on both sides thereof, or a transparent protective film made of a different resin material may be used.

 The surface of the transparent protective film on which the polarizer is not adhered may be subjected to a hard coat layer / anti-reflection treatment, anti-stating treatment, or treatment for diffusion or anti-glare.

 Hard coat treatment is performed to prevent scratches on the polarizing plate surface.

For example, it can be formed by a method of adding a cured film having an excellent hardness and a sliding property with an appropriate ultraviolet curable resin such as an acrylic or silicone resin to the surface of the transparent protective film. The anti-reflection treatment is performed for the purpose of preventing reflection of external light on the polarizing plate surface, and can be achieved by forming an anti-reflection film or the like according to the related art. The anti-stating treatment is performed to prevent adhesion to the adjacent layer. The anti-glare treatment is performed to prevent external light from being reflected on the surface of the polarizing plate and hindering the visibility of light transmitted through the polarizing plate. It is formed by giving a fine uneven structure to the surface of the transparent protective film by an appropriate method such as a roughening method using a sandplast method or an embossing method, or a method of blending transparent fine particles. Can be. Examples of the fine particles to be contained in the formation of the fine surface unevenness structure include silica, alumina, titania, dinorecoure, and acid oxide having an average particle size of 0.5 to 50 / zm.

, Indium oxide, cadmium cadmium, and antimony oxidized antimony, and the like. Bright fine particles are used. When forming the fine surface uneven structure, the amount of the fine particles used is generally about 2 to 50 parts by weight with respect to 100 parts by weight of the transparent resin forming the fine surface uneven structure, and 5 to 25 parts by weight. Parts by weight are preferred. The anti-glare layer may also serve as a diffusion layer (such as a viewing angle enlargement function) for diffusing light transmitted through the polarizing plate to increase the viewing angle and the like.

 The anti-reflection layer, anti-stating layer, diffusion layer, anti-glare layer and the like can be provided on the transparent protective film itself. Alternatively, it can be provided as an optical layer separately from the transparent protective film.

 In practical use, an optical film in which another optical element (optical layer) is laminated on the polarizing plate can be used. The optical layer is not particularly limited. For example, it is used for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wavelength plate such as 12 or 1/4), and a viewing angle compensation film. One or more optical layers that may be used can be used. In particular, a reflective polarizing plate or a transflective polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a transflective reflecting plate, an elliptically polarizing plate or a circular polarizing plate in which a polarizing plate is further laminated with a retardation plate, A wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on a polarizing plate, or a polarizing plate in which a brightness enhancement film is further laminated on a polarizing plate is preferable. In an elliptically polarizing plate or a polarizing plate with optical compensation, an antireflection film is provided on the polarizing plate side.

 In addition, as required, various special features such as scratch resistance, durability, weather resistance, moisture and heat resistance, heat resistance, moisture resistance, moisture permeability, antistatic properties, conductive ft, improved adhesion between layers, improved mechanical strength, etc. It is also possible to perform processing for imparting properties, functions, etc., or insert, laminate, etc. functional layers.

 The reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side) to display. There is an advantage that the built-in light source such as a backlight can be omitted, and the liquid crystal display device can be easily made thinner. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is provided on one surface of the polarizing plate via the transparent protective film or the like, if necessary.

A specific example of a reflective polarizing plate is a transparent protective film that has been matted if necessary. On one side, a reflective layer is formed by attaching a foil made of a reflective metal such as aluminum or the like to a vapor deposition film.

 The reflection plate may be used as a reflection sheet or the like in which a reflection layer is provided on an appropriate film according to the transparent film, instead of the method of directly applying the reflection plate to the transparent protective film of the polarizing plate. Since the reflective layer is usually made of a metal, the use of the reflective layer covered with a transparent protective film, a polarizing plate, or the like prevents the reduction of the reflectance due to oxidation, and thus the long-lasting initial reflectance. This is more preferable in terms of avoiding the additional provision of a protective layer.

 In addition, the transflective polarizing plate can be obtained by forming a transflective reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell. When a liquid crystal display device or the like is used in a relatively bright atmosphere, an image is reflected by reflecting incident light from the viewing side (display side). In a relatively dark atmosphere, it is possible to form a liquid crystal display device that displays an image using a built-in light source such as a backlight built in the back side of a transflective polarizing plate. In other words, a transflective polarizing plate can save energy for using a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device that can be used with a built-in light source even in a relatively dark atmosphere. It is. An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. When changing linearly polarized light to elliptically or circularly polarized light, for changing elliptically or circularly polarized light to linearly polarized light, or for changing the polarization direction of linearly polarized light, a retardation plate or the like is used. In particular, a so-called quarter-wave plate (also referred to as an LZ4 plate) is used as a retardation plate for converting linearly polarized light to circularly polarized light or for converting circularly polarized light to linearly polarized light. A half-wave plate (also called λΖ2 plate) is usually used to change the polarization direction of linearly polarized light.

The elliptically polarizing plate compensates (prevents) the coloring (blue or yellow) caused by the birefringence of the liquid crystal layer of the super twisted nematic (STN) type liquid crystal display device, and is effective in the case of black-and-white display without the above-mentioned coloring. Used. Further, the one in which the three-dimensional refractive index is controlled is preferable because coloring which occurs when the screen of the liquid crystal display device is viewed from an oblique direction can be compensated (prevented). Circular polarizers are, for example, reflective liquid crystals that display images in color. It is effectively used for adjusting the color tone of an image on a display device, and has a function of preventing reflection. Specific examples of the above-mentioned retardation plate include a multilayer formed by stretching a film made of an appropriate polymer such as polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene or other polyolefin, polyarylate, or polyamide. Refractive film-an alignment film of a liquid crystal polymer, and a film in which an alignment layer of a liquid crystal polymer is supported by a film. The retardation plate may have an appropriate retardation according to the purpose of use, such as, for example, various wavelength plates or ones for the purpose of compensating the viewing angle or the like due to birefringence of the liquid crystal layer. A device in which optical characteristics such as retardation are controlled by laminating retardation plates may be used.

 Further, the elliptically polarizing plate or the reflection type elliptically polarizing plate is obtained by laminating a polarizing plate or a reflection type polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially and separately laminating a (reflection type) polarizing plate and a retardation plate in a manufacturing process of a liquid crystal display device so as to form a combination. The use of an optical film such as an elliptically polarizing plate in advance has the advantage of being superior in quality stability, laminating workability, etc., and capable of improving the production efficiency of a liquid crystal display device and the like.

The viewing angle compensation film is a film for widening the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction, not perpendicular to the screen. Such a viewing angle compensating retardation plate includes, for example, a retardation film, an alignment film such as a liquid crystal polymer, or a film in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. A common retardation plate is a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film is biaxially stretched in the plane direction. Birefringent polymer film and force, biaxially stretched uniaxially in the plane direction and also stretched in the thickness direction. A stretched film or the like is used. Examples of the obliquely oriented film include, for example, a film obtained by bonding a heat shrink film to a polymer film and subjecting the polymer film to a stretching treatment and / or a shrinking treatment under the action of the shrinkage force caused by heating, or a film obtained by obliquely orienting a liquid crystal polymer. Is mentioned. The raw material polymer of the retardation plate is the polymer described for the retardation plate The same material as that described above can be used, and an appropriate material can be used for the purpose of preventing coloring or the like due to a change in the viewing angle based on the phase difference due to the liquid crystal cell, expanding the viewing angle for good visibility, and the like. In addition, because of achieving a wide viewing angle with good visibility, the optical compensation phase difference, in which an optically anisotropic layer consisting of a liquid crystal polymer alignment layer, especially a discotic liquid crystal polymer inclined alignment layer, is supported by a triacetyl cellulose film. A plate can be preferably used. A polarizing plate obtained by laminating a polarizing plate and a brightness enhancement film is usually used by being provided on the back side of a liquid crystal cell. The brightness enhancement film reflects linearly polarized light with a predetermined polarization axis or circularly polarized light in a predetermined direction when natural light is incident due to reflection from the back side of a pack light such as a liquid crystal display device, and transmits other light. The polarizing plate in which the brightness enhancement film is laminated with the polarizing plate receives light from a light source such as a backlight to obtain transmitted light in a predetermined polarization state, and does not transmit light other than the predetermined polarization state. Is reflected by The light reflected on the surface of the brightness enhancement film is further inverted via a reflection layer or the like provided on the rear side thereof and re-entered on the brightness enhancement film, and a part or all of the light is transmitted as light of a predetermined polarization state to thereby obtain brightness. The brightness can be improved by increasing the amount of light transmitted through the enhancement film and by increasing the amount of light that can be used for liquid crystal display image display by supplying polarized light that is hardly absorbed by the polarizer. In other words, when light is incident through a polarizer from the back side of a liquid crystal cell with a backlight or the like without using a brightness enhancement film, it has a polarization direction that does not match the polarization axis of the polarizer. Most of the light is absorbed by the polarizer and does not pass through the polarizer. That is, although it depends on the characteristics of the polarizer used, about 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display etc. decreases, and the image becomes Get dark. In the brightness enhancement film, light having a polarization direction that is absorbed by the polarizer is once reflected by the brightness enhancement film without being incident on the polarizer, and then inverted through a reflection layer provided on the back side. And then re-incident on the brightness enhancement film, and only the polarized light whose polarization direction is reflected or inverted between the two and has become such that the light can pass through the polarizer is reflected on the brightness enhancement film. Since light is transmitted to the polarizer and supplied to the polarizer, light from a backlight or the like can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

A diffusion plate may be provided between the brightness enhancement film and the above-mentioned reflection layer or the like. Brightness direction The light in the polarization state reflected by the upper film is directed to the reflection layer and the like, but the diffuser provided diffuses the light passing therethrough at the same time, and at the same time, eliminates the polarization state and becomes a non-polarized state. That is, the diffuser returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the light in the natural light state is repeatedly directed to the reflection layer and the like, reflected through the reflection layer and the like, again passed through the diffuser and re-incident on the brightness enhancement film. In this way, by installing a diffusion plate between the brightness enhancement film and the above-mentioned reflective layer, etc., to return the polarized light to the original natural light state, the brightness of the display screen is maintained, and at the same time, the brightness unevenness of the display screen is reduced. , Can provide a uniform and bright screen. It is considered that by providing such a diffusion plate, the initial incident light was moderately increased in the number of repetitions of reflection, and together with the diffusion function of the diffusion plate, a uniform bright display screen could be provided. The brightness enhancement film has a property of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of a dielectric or a multilayer laminate of thin films having different refractive index anisotropy. As shown in the figure, the characteristic of reflecting either left-handed or right-handed circularly polarized light and transmitting other light, such as an alignment film made of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate. Appropriate ones such as those shown can be used.

 Therefore, in the above-described brightness enhancement film that transmits the predetermined polarization axis (^ linearly polarized light), the transmitted light is directly incident on the polarization plate with the polarization axis aligned, thereby suppressing absorption loss by the polarization plate and improving efficiency. On the other hand, a brightness enhancement film that transmits circularly polarized light, such as a cholesteric liquid crystal layer, can be incident on a polarizer as it is. It is preferable that the light be converted into linearly polarized light through a phase difference plate and then be incident on the polarizing plate, by using a quarter-wave plate as the phase difference plate, circularly polarized light can be converted into linearly polarized light.

A retardation plate that functions as a 14-wavelength plate in a wide wavelength range such as the visible light region is, for example, a retardation layer that functions as a 1Z 4-wavelength plate for light-colored light with a wavelength of 550 nm and other retardation characteristics. , For example, a method of superimposing a retardation layer functioning as a one-to-two wavelength plate. Therefore, between the polarizing plate and the brightness enhancement film May be composed of one or two or more retardation layers.The cholesteric liquid crystal layer may also be composed of two or more layers with different reflection wavelengths. With such an arrangement structure, it is possible to obtain circularly polarized light that reflects circularly polarized light in a wide wavelength range such as a visible light region, and based on this, it is possible to obtain transmitted circularly polarized light in a wide wavelength range.

 Further, the polarizing plate may be formed by laminating a polarizing plate and two or three or more optical layers as in the above-mentioned polarized light separating type polarizing plate. Therefore, a reflective elliptically polarizing plate or a transflective elliptically polarizing plate obtained by combining the above-mentioned reflective polarizing plate, semi-transmissive polarizing plate and retardation plate may be used. When laminating the above-mentioned polarizing plate or other optical films, their optical axes can be arranged at an appropriate angle depending on the intended retardation characteristics and the like.

The touch panel section 1 and the display panel section 2 are brought into close contact with each other via an adhesive layer 3. When the adhesive layer 3 adheres, the surface of the lower substrate 12 of the touch panel unit 1 and the surface of the front surface of the display panel unit 2 are subjected to corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, sputter etching treatment, and undercoat treatment. Adhesion can be improved by performing appropriate treatments such as bombard discharge treatment, electron beam irradiation, chemical conversion, oxidation, and flame. As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 6, an acryl-based pressure-sensitive adhesive containing, as a base polymer, an acryl-based polymer having a functional group concentration of 5 × 10 ⁴ mol Zg or less can be used without any particular limitation. Acrylic adhesives are excellent in transparency, weather resistance, heat resistance, and the like. As the acrylic polymer, as a monomer which is a main component exhibiting appropriate wettability and flexibility, one or more of acrylate and methacrylate esters having a glass transition temperature of 110 ° C. or lower. Those using two or more kinds are exemplified.

 Further, as the above-mentioned ester, for example, an n-butylinole group

, Isobutyl, isoamino, hexyl, heptyl, cyclohexyl,

Acrylic having an organic group consisting of an alkyl group having 4 or more carbon atoms such as 2-ethylhexyl group, isooctyl group, isononyl group, lauryl group, dodecyl group, isomyristyl group, octadecyl group, etc. Acid esters ゃ methacrylic acid esters are preferred. The number of coal layers such as methyl group, ethyl group and propyl group is 3 or less. Atalinoleic acid ester / methacrylic acid ester having a functional group can be used as a combination system.

 The acrylic polymer contains, as a copolymer component, a functional group-containing monomer for improving the cohesiveness or adhesiveness of the pressure-sensitive adhesive or for imparting crosslinking reactivity. The functional group-containing monomer is not particularly limited as long as it can be copolymerized with the above-mentioned main component monomer. Examples of the functional group-containing monomer include monomers having a functional group such as a carboxyl group, a hydroxyl group, an epoxy group, an amide group, an imido group, a sulfonic acid group, and a phosphoric acid group.

 Examples of the functional group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, carboxyl group-containing monomers such as itaconic acid, maleic acid, and crotonic acid, and (meth) acrylic acid. 2-hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate Contains a hydroxyl group such as 10-hydroxydecyl (meth) acrylate, 12-hydroxylaurinolate (meth) atalinoleate, or 4-methylhydroxycyclohexyl monomethyl phthalate Monomers, epoxy group-containing monomers such as glycidyl (meth) acrylate, and the like. Also, (meth) atarylamide, N-acryloylmorpholine, N-substituted (meth) acrylamide, N

-Amide monomers such as vinylinolepyrrolidone, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide and other maleimide monomers, N-methylitacon Imid, N-Ethylitaconimid

Itaconimid-based monomers such as N-butylitaconimid, N-octylitaconimid, N-2-ethylhexylitaconimid, N-cyclohexylitaconimid, N-laurylitaconimid, etc. Succinimides such as N- (meta) atariloyloxymethylene succinimide, N- (meta) atariloyl-1-6-hexoxyhexamethylene succinimide, N- (meta) acryloylone 8-octoxytatamethylene succinimide Monomers, sulfonic acid group-containing monomers such as 2-acrylamide 2-methylpropane sulfonic acid, and phosphoric acid group-containing monomers such as 2-hydroxylethylacryloyl phosphate. The functional group-containing monomer is useful for intermolecular crosslinking via the functional group and an intermolecular crosslinking agent. The pressure-sensitive adhesive layer according to the present invention is used in an appropriate amount within a range that satisfies a predetermined functional group concentration. In general, depending on the type of the main component monomer, the copolymer obtained is usually 4% by weight or less, more preferably 2% by weight or less, particularly 1% by weight or less, based on the main component monomer. The functional group concentration can be set in the above-mentioned predetermined range.

 As the functional group-containing monomer, a monomer that efficiently functions as a crosslinking reaction point even when the functional group concentration is low is preferably used. The above-mentioned 5-carboxypentyl acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, (meth) acrylic acid, Monomers having a functional group at the end of a relatively long methylene chain, such as 10-hydroxydecyl (meth) atalinoleate and 12-hydroxylauryl (meth) acrylate, may be used in copolymers. Since the degree of freedom of the movement of the functional group is large, the force and crosslinking reaction are rich, and a sufficient crosslinking effect can be exerted with a small copolymerization ratio of about 0.5% by weight.

 Other copolymerizable monomers used for the purpose of controlling the cohesiveness and adhesiveness of the pressure-sensitive adhesive include, for example, vinyl monomers such as butyl acetate and styrene, and dibutyl monomers such as dibutylbenzene. Diacrylate monomers such as 1,4-butyl acrylate, 1,6-hexyl diacrylate, tetrahydrofuranolylfuryl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, Acrylic ester monomers such as fluorinated (meth) acrylates and silicone (meth) acrylates; alkoxy group-containing monomers such as trimethoxysilyl propyl acrylate; maleic anhydride and itaconic anhydride Examples include anhydrous monomers. Since the acid anhydride monomer may generate a carboxyl group by hydrolysis in the copolymer, it is necessary to consider it from the viewpoint of controlling the functional group concentration.

The polyfunctional acrylate-based monomer and the like can be used as a copolymerized monomer as necessary, for example, when a crosslinking treatment is carried out by irradiation with radiation such as an electron beam or the like by a post-crosslinking operation without adding a crosslinking agent. Examples of such monomers include hexanediol di (meth) a Acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) atalylate, neopentyl glycol di (meth) atalylate, pentaerythritol di (meth) atalylate, trimethylolpropane tri (meta) Acryl-based polymers such as atalylate, pentaerythri-tonoretri (meth) acrylate, dipentaerythri-tonorehexa (meth) atalylate, epoxyacrylate, polyester acrylate, urethane acrylate, etc. are prepared. An appropriate system such as a solution polymerization system, an emulsion polymerization system, a bulk polymerization system, a suspension polymerization system, or the like can be applied to a mixture of at least one kind of each monomer. In the case of the bulk polymerization method, a polymerization method using ultraviolet irradiation can be preferably applied. In that case, it is necessary to control the amount of the functional group-containing copolymerizing monomer to be used in order to achieve a predetermined functional group concentration of the acrylic polymer obtained as described above. Acrylic polymers have a weight-average molecular weight of 400,000 or more, more preferably 800,000 to 400,000, and especially 100,000 to 300,000 in terms of wet heat resistance. .

 In preparing the acryl polymer, a polymerization initiator may be used as necessary. The amount used can be appropriately determined, but is generally from 0.001 to 5% by weight of the total amount of the monomers. As the polymerization initiator, an appropriate one such as a thermal polymerization initiator or a photopolymerization initiator can be used according to the polymerization system.

 Examples of thermal polymerization initiators include benzoyl peroxide, t-butyl perbenzoate

, Cumene dropperoxide, diisopropylperoxydicarbonate, di-n-propinoleveroxydicarbonate, di (2-ethoxyxenotinole) peroxy dicarbonate, t-butyl peroxy neodecanoate, t-butyl boroxivalate, (3 , 5,5-trimethylhexanoyl) Organic peroxides such as peroxide, dipropionyl peroxide, and diacetyl peroxide. Also, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1, -azobis (cyclohexane 1_carbonitrile), 2,2,1 Azobis (2,4-dimethylvaleronitrile), 2, 2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2, 2 ' —Azobis (2-methylinopropionate), 4,4,1-azobis (4-cyanovaleric acid), 2,2 ′ —azobis (2-hydroxymethylpropionitrile), 2, 2 ′ —azobis [ Azo compounds such as 2- (2-imidazoline_2-yl) propane]. '

 Examples of photopolymerization initiators include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-12-propynole) ketone, α-hydroxy-α, α'-dimethinoleacetophenone, methoxyacetophenone, 2,2- Dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) -phenyl] -acetophenone-based initiator such as 2-morpholinopropane-11, benzoine Benzoin ether-based initiators such as tinol ether and benzoin isopropyl ether ether. Also, ketal-based initiators such as benzyldimethyl ketanol, benzophenone, benzoylbenzoic acid, benzophenone-based initiators such as 3,3'-dimethyl-4-methoxybenzophenone, thioxanthone, and 2-cloxanthioxanson. , 2-Methinorethioxanthone, 2,4-Dimethinolethioxanthone, Isopropyl thioxanson, 2,4-Dichloromouth thioxanthone, 2,4-Diethylthioxanthone, 2,4-Diisopropinolethioxanson Thioxanthone-based initiators, such as camphorquinone-halogenated ketones, and other polymerization initiators such as persulfate, persulfate, ammonium persulfate, hydrogen peroxide, etc .; Initiators and the like.

 The pressure-sensitive adhesive layer may be subjected to a crosslinking treatment as described above. In this case, the crosslinking treatment with the intermolecular crosslinking agent can be performed by a method of blending the intermolecular crosslinking agent with the adhesive liquid. As the intermolecular crosslinking agent, an appropriate one can be used according to the type of the functional group in the base polymer involved in the intermolecular crosslinking, and is not particularly limited. Therefore, any of the known materials can be used.

Examples of the intermolecular cross-linking agent include multifunctional isocyanate-based cross-linking agents such as tolylene disocyanate, trimethylolpropane tolylene diisocyanate, diphenyl methane triisocyanate, and polyethylene glycol diglycidyl ether. The Epoxy crosslinkers such as glycidyl ether and trimethylolpropane triglycidyl ether, melamine resin crosslinkers, metal salt crosslinkers, metal chelate crosslinkers, amino resin crosslinkers, silane coupling agents, etc. can give.

The amount of the intermolecular crosslinking agent can be appropriately determined according to the content of the functional group in the base polymer. In general, it is 0.005 to 20 parts by weight, more preferably 0.01 to 15 parts by weight, especially 0.1 to 10 parts by weight, based on 100 parts by weight of the base polymer. Elastic modulus of the preferred pressure-sensitive adhesive layer from the point of view of heat resistance and moisture resistance of the antifoam or the like, 1 based on 1 0 0 0% modulus in the tensile test at 9 0 ° C O m N / mm 2 or more, further ² 0 mNZmm 2 or more, in particular 4 0 mN, mm ² or more.

 In the pressure-sensitive adhesive layer, fillers, pigments, and coloring agents such as natural and synthetic resins, glass fibers, glass beads, metal powders, and other inorganic powders may be used as needed as long as transparency is not impaired. An appropriate caroten, which may be added to the pressure-sensitive adhesive layer, such as an antioxidant or an anti-irritating agent, may be added. Further, a pressure-sensitive adhesive layer having light diffusibility can be formed by incorporating fine particles. The cohesive force of the pressure-sensitive adhesive layer can be determined by a conventional method such as the composition and molecular weight of the polymer, the crosslinking method and the degree of crosslinking, and the addition of optional components.

 The attachment of the pressure-sensitive adhesive layer can be performed by an appropriate method. As an example, for example, an adhesive is dissolved or dispersed in a solvent composed of an appropriate solvent alone or a mixture such as toluene or ethyl acetate to prepare an adhesive liquid of about 10 to 40% by weight. Directly on the touch panel or display panel by an appropriate development method such as a casting method or a coating method, or by forming an adhesive layer on a separator and transferring it to an optical film material as described above. There is a method of wearing.

The pressure-sensitive adhesive layer can be provided as a different layer on the superposed layer or on the front and back of the material, and the thickness can be appropriately determined according to the purpose of use. In general, the thickness is set to 1 to 500 μm, more preferably 5 to 200 μm, particularly 10 to 100 μηη from the viewpoint of optical characteristics and additional properties. Sometimes more than 1 mm thick. When the pressure-sensitive adhesive layer is exposed on the surface, it is preferable to protect the surface with a separator or the like until practical use. Example

 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples. The parts in each example are parts by weight.

Example 1

 (Preparation of display panel)

 To a composition consisting of 90 parts of an ultraviolet-curable polyester acrylate, 10 parts of urethane acrylate, and 3 parts of a benzophenone-based photopolymerization initiator, 8 parts of amorphous silica particles having a particle size of 1 to 8 m was added, and the viscosity was further increased. After the adjustment solvent (toluene) was added, the mixture was stirred at a high speed to prepare a mixed solution having a solid content of 50% by weight. The mixed solution was applied to one surface of a 50 μm-thick triacetate film, and after evaporating the solvent, the film was irradiated with ultraviolet rays to produce a film with an anti-glare layer having a thickness of 8 μππι.

 A uniaxially stretched 3 O / xm polyvinyl alcohol film-polarized polarizer is dyed with iodine, and the anti-glare layer is put on the outermost layer by the above film with an anti-glare layer and a 50 μππι-thick triacetate film. Thus, a laminated polarizing plate was manufactured. A liquid crystal display device (display panel) was manufactured by stacking the polarizing plate on a liquid crystal cell such that the antiglare layer was the outermost layer.

 The liquid crystal cell was constructed by disposing and fixing a spacer having a predetermined thickness between two mirror-finished mold surfaces, and injecting an alicyclic epoxy resin. It was heated and cured at 2 ° C for 2 hours, cooled, and taken out to produce a 0.1 mm thick transparent plastic substrate. After the substrate was cut into a predetermined shape, a plasma treatment was performed in an atmosphere of anoregon, and a thin film of indium tin oxide (Ι) was formed by sputtering to produce a transparent substrate for liquid crystal. Using a pair of the above substrates, a polybutyl alcohol solution was applied to the surface on the electrode side by spin coating, dried, and then subjected to a rubbing treatment to produce a rubbing film. The transparent electrode on one substrate is divided into two by etching in advance. After that, a pair of the above substrates is opposed to the transparent electrodes so that the rubbing directions are orthogonal to each other, and a gap adjusting material is provided.

“ZLI—4792” was injected to fabricate a Τ-type liquid crystal cell.

 (Production of touch panel)

Use a transparent polyester film (upper substrate) of thickness 17 5 A cryl resin was applied to a thickness of 5 μπι by ultraviolet curing. Next, a melamine-based resin was applied to the other side by thermosetting so as to have a thickness of 40 nm. Next, a film was formed to a thickness of 20 nm by a sputtering method using an ITO target of 10% by weight of tin oxide to form an upper electrode. On the other hand, a transparent polyesterfinolene (lower substrate) of 125 μπι was used, and a melamine-based resin was applied on one surface to a thickness of 40 nm by thermosetting. Next, a lower electrode was formed by sputtering to a thickness of 20 nm using an ITO target of 10% by weight of tin oxide. Then, a UV-curable ink (Seiko Advance Co., Ltd. # 9051) is printed on the lower electrode surface at a pitch of lmm in the form of small projections with a diameter of 0.08 mm using a silk screen, and cured by irradiating UV light. Then, a dot spacer was formed. A touch panel was manufactured by overlapping the upper electrode with the ITO film facing the lower electrode.

 (Preparation of acrylic adhesive)

In a reaction vessel equipped with a cooling pipe, a nitrogen inlet pipe, a thermometer and a stirrer, add 99.7 parts of isooctyl acrylate, 0.3 part of 6-hydroxyhexyl atalylate and 2,2'-azobisisobutyrate. After 0.3 part of lonitonyl was added together with ethyl acetate, the mixture was reacted at 60 ° C. for 4 hours under a nitrogen gas stream. Ethyl acetate was added to the reaction solution to obtain an acrylic polymer solution having a solid content of 30% by weight. This solution was mixed with 0.1 part of γ-glycidoxypropyl tokimesisilane per 100 parts of the solid content to prepare an acrylic pressure-sensitive adhesive. The weight average molecular weight of the acrylic polymer is 1 940 000 in terms of polystyrene by genomic les par Miyu instantiation chromatography primary, functional group concentration was 0. 17 X 10- ⁴ mol / g.

 (Production of image display device with touch panel)

Coating the Akuriru based adhesive on the lower substrate of Tatsuchipaneru, to form a pressure-sensitive adhesive layer having a thickness of 25 mu _m and dried. The anti-glare layer of the display panel was bonded to this to produce an image display device with a touch panel.

Example 2

In Example 1 (preparation of acrylic pressure-sensitive adhesive), 99.8 parts of butyl acrylate and 0.2 part of 4-hydroxybutyl acrylate were used as monomers. Average molecular weight of 7 00000, functional group concentration 0. Was 1 4 X 1 0- ⁴ mol / g of Atariru polymer solvent solution was prepared. An acrylic pressure-sensitive adhesive was prepared by mixing 0.3 parts of trimethylolpropane tolylene diisocyanate with 100 parts of the solid content of the solution. In Example 1 (production of an image display device with a touch panel), an image display device with a touch panel was made in the same manner as in Example 1 except that the above-mentioned acrylic adhesive was used.

Comparative Example 1

In Example 1 (Preparation of acrylic adhesive), using an acrylic Sambu chill 9 5 parts of Akuriru acid 5 parts monomer, the weight average molecular weight 1 4 50,000, the functional group concentration 6. 9 X 1 0- ⁴ An acrylic pressure-sensitive adhesive was prepared in the same manner as in Example 1, except that an acrylic polymer solution of mol Z g was prepared. An image display device with a touch panel was produced in the same manner as in Example 1 (production of an image display device with a touch panel) except that the acrylic pressure-sensitive adhesive was used.

Comparative Example 2

In Example 1 (preparation of an acrylic pressure-sensitive adhesive), 95 parts of butyl acrylate, 4.8 parts of acrylic acid, and 0.2 part of 2-hydroxyhexyl acrylate were used as monomers to obtain a weight average molecular weight of 15 5 ten thousand, the functional group concentration of 6. 8 a § acrylic-based polymer solution of X 1 0 _ ⁴ moles 8 were prepared. To this solution, 1.2 parts of trimethylolpropane tolylene diisocyanate was mixed with 100 parts of the solid content to prepare an acryl-based pressure-sensitive adhesive. An image display device with a touch panel was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive was used in Example 1 (production of an image display device with a touch panel).

 The following evaluation was performed on the image display device with a touch panel obtained above. Table 1 shows the results.

 (Peel adhesion)

After preparing an image display device (sample) with a touch panel, the sample was left in an autoclave at 50 ° C and 5 atm for 30 minutes to mature the bonded state. Adhesion (N ^ O mm) was measured at a peeling rate (peeling rate of 10 O mm / min, 25 ° C). Peeling was performed by peeling the touch panel from the display panel. (Reworkability)

 With respect to the sample after peeling used in the measurement of the peel adhesive strength, it was visually determined on which surface the pressure-sensitive adhesive layer was. The case where the surface area of the pressure-sensitive adhesive layer occupying the touch panel side was 98% or more was rated “〇”. If the pressure-sensitive adhesive layer remains on the touch panel side in the state of “〇”, the peel adhesion was measured at the interface A between the display panel and the pressure-sensitive adhesive layer, and the peeling adhesive strength was measured. It is recognized that the peel adhesion at interface B between the adhesive layer and the touch panel is larger than the peel adhesion at interface A. Cases other than the above “〇” were designated as “X”. When the pressure-sensitive adhesive layer remained almost the same on both sides of the touch panel and the cover panel, it was regarded as cohesive failure.

 (Pen input)

 From the touch panel side of the image display device with a touch panel, a pen (material: polyacetal, tip 0.8 r) is slid linearly 100 times at a speed of 5 ON / min to deform or peel off the input part. Was evaluated according to the following criteria by visual appearance judgment. Regarding peeling, the criteria for acceptance was that there was no peeling with a diameter of 20 μπι or more.

 〇: No deformation affecting visibility, no deformation affecting visibility, and no peeling.

 X: Deformation affecting visibility, deformation affecting visibility, and peeling.

 (reliability)

 After the sample was placed in an atmosphere of 60 ° C. and 95% RH for 500 hours, peeling, floating, foaming, and discoloration were visually evaluated based on the following criteria by visual appearance judgment. Regarding peeling, the criteria for acceptance was that there was no peeling of 20 μπι or more in diameter.

 〇: No peeling or foaming affecting visibility.

X: Peeling or foaming affecting visibility.

Table 1

Industrial applicability

 The present invention is an image display device with a touch panel, in which the interface between the display panel and the touch panel is brought into close contact with each other via an adhesive layer, and has an excellent display quality. Can be easily reused, and is useful as an image display device with a touch panel.

Claims

The scope of the claims 1. A touch panel having an upper substrate, a lower substrate opposed to the upper substrate, a transparent electrode formed on a facing surface of each of the substrates, and a display panel unit. In an image display device with a touch panel panel in which the lower substrate and the front surface of the display panel are in close contact with each other via an adhesive layer, Upper and lower substrates of Tatsuchipanenore unit is both a polymer film, Chikaratsuneba Chakuzaiso is, the functional group concentration containing an acrylic polymer of the following 5 X 1 0- ⁴ mol Z g as Besupo Rimmer adhesive An image display device with a touch panel, wherein the image display device is formed of an agent.  2. The claim according to claim 1, wherein the functional group is at least one selected from a carboxy group, a hydroxyl group, an epoxy group, an amide group, an imido group, a sulfonate group and a phosphate group. Item 2. The image display device with a touch panel according to item 1.  3. When the interface between the display panel and the pressure-sensitive adhesive layer is A and the interface between the pressure-sensitive adhesive layer and the adhesive layer is B, the peeling adhesive strength at the interface satisfies A <B, and 90 ° peeling at interface A 3. The image display device with a touch panel according to claim 1, wherein the adhesive force is 1 to 6 N / 20 mm.