JP4647631B2 - High durability touch panel - Google Patents

Description

  The present invention relates to a touch panel that does not cause deterioration of antireflection characteristics due to retardation change even when left in a high temperature environment for a long time, can perform a comfortable input operation, and has high durability with good workability during assembly. It is used mainly for car navigation and the like.

  2. Description of the Related Art Conventionally, a touch panel is disposed on the front surface of displays such as LCDs, organic ELs, and CRTs that are widely used in products such as PDAs (personal digital assistants), mobile phones, and personal computers. The basic structure of the touch panel includes an upper electrode plate having an upper electrode made of a transparent conductive film on the lower surface and a lower electrode plate having a lower electrode made of a transparent conductive film on the upper surface. It has a structure in which it is opposed and fixed only outside the display area through the air layer, and both electrodes insulated by the air layer are brought into contact with each other by pressing a part of the panel surface to be electrically connected. It can be input. Further, the upper electrode plate and the lower electrode plate are each constituted by a single layer or a plurality of layers laminated by whole surface adhesion.

  And for the use used outdoors, in order to prevent reflection of external light and improve the visibility, the upper electrode plate 1 is arranged in order from the upper electrode 2 side to the quarter-wave plate 9 and the 1 / A low reflection touch panel in which the polarizing plate 10 having an optical axis and an absorption axis of 45 ° or 135 ° of the four-wavelength plate 9 is laminated (see FIG. 4) can be used. The quarter-wave plate 9 and the polarizing plate 10 form a circular polarization type antireflection filter, and the reflection of light incident from the outside on the transparent conductive film is efficiently cut. In the case where the display is an LCD, if only one quarter-wave plate 9 is used, the linearly polarized light incident for display from the LCD side is also changed to circularly polarized light. The phase is canceled by arranging in the lower electrode plate 3 a quarter-wave plate whose optical axis is orthogonal to the quarter-wave plate 9. That is, after being made circularly polarized by the ¼ wavelength plate on the lower electrode 4 side, it is returned to the original linearly polarized light again by the ¼ wavelength plate 9 on the upper electrode 2 side.

  In recent years, car navigation has become widespread in the automobile industry, and these mainly use screen operations with a remote controller, but it is considered to use a touch panel on a display screen in order to make the operability more comfortable. In that case, in order to prevent the visibility from being deteriorated due to reflection of outdoor light such as sunlight, a touch panel having the above-described circular polarization type antireflection filter is essential. However, under the direct sunlight in the summer, in a car with the window closed, it may be in a high temperature environment exceeding 70 ° C. In this case, it will expand if left for a long time, but the quarter wavelength plate in the upper electrode plate 1 9 and the polarizing plate 10 have different expansion directions at the time of axis formation, and thus exhibit different expansion directions 11 when directly or indirectly bonded on the entire surface (see FIG. 5). There is a risk of undulation or distortion in 1. Further, under the high temperature environment, the expansion of the quarter wave plate 9 in the upper electrode plate 1 is free in the central portion, but is influenced by partial adhesion and fixation with the lower electrode plate 3 in the peripheral portion. As a result, the stress 12 is applied only to the peripheral edge of the quarter-wave plate 9 (see FIG. 6), and the quarter wavelength near the peripheral edge of the display area. There is a possibility that the retardation value of the plate 9 changes and the antireflection characteristic is impaired.

  Therefore, as a car navigation application, there is one in which the glass plate 13 is disposed in the upper electrode plate 1 and bonded to the quarter-wave plate 9 over the entire surface so that the above problem does not occur (see FIG. 7). By laminating the glass plate on the entire surface of the quarter-wave plate 9 in the upper electrode plate 1, the quarter-wave plate 9 and the polarizing plate 10 hardly cause thermal expansion even in a high temperature environment exceeding 70 ° C. The state without undulation or distortion is maintained. Moreover, since the stress applied to the quarter-wave plate 9 is dispersed by bonding a highly rigid glass plate to the quarter-wave plate 9 over the entire surface, the retardation change hardly occurs and the antireflection characteristics are impaired. Less is.

  However, the upper electrode plate 1 is a part that directly touches a finger or a pen. When a glass plate is used in the upper electrode plate 1, the glass plate has high rigidity. Becomes heavier. In order to perform a comfortable input operation, it is necessary to set the glass thickness very thin. However, since it becomes very easy to break by using a glass plate having such a thickness, handling at the time of assembling the touch panel becomes very difficult, and the glass may be broken during the touch panel input operation.

  Therefore, an object of the present invention is to solve the above-mentioned problem, and even if it is left for a long time in a high-temperature environment, the anti-reflection property is not deteriorated due to deformation of the external shape or retardation change, and the input is comfortable. An object of the present invention is to provide a touch panel that can be operated and has high durability with good workability during assembly.

  In order to achieve the above object, the present invention is configured as follows.

According to the first aspect of the present invention, an upper electrode plate having an upper electrode made of a transparent conductive film on the lower surface and a lower electrode plate having a lower electrode made of a transparent conductive film on the upper surface The upper electrode plate is arranged to be opposed and fixed only outside the display area through an air layer, and the upper electrode plate is arranged in order from the upper electrode side, and the optical axis and the absorption axis of the quarter wavelength plate. In a touch panel formed by laminating at least a polarizing plate having an angle of 45 ° or 135 °,
The upper electrode plate is an optically isotropic heat resistant transparent resin plate having a thickness of 0.15 to 0.8 mm having a glass transition temperature of 150 ° C. or more and a water absorption of 1.3% or less. Provided is a touch panel having high durability, which is provided between a quarter-wave plate and the heat-resistant transparent resin plate is directly bonded to the quarter-wave plate directly on the entire surface.

  According to the 2nd aspect of this invention, the glass transition temperature of the said heat resistant transparent resin board provides the highly durable touch panel as described in a 1st aspect which is 170 degreeC or more.

  According to a third aspect of the present invention, there is provided a highly durable touch panel according to the first aspect, wherein the heat-resistant transparent resin plate has a thickness of 0.2 to 0.7 mm.

  According to a fourth aspect of the present invention, there is provided the highly durable touch panel according to the first aspect, wherein the heat-resistant transparent resin plate has a water absorption rate of 1% or less.

  According to the fifth aspect of the present invention, in the first aspect, a moisture-proof PET film is disposed as a satin layer with a low reflection / antifouling function on the upper surface of the polarizing plate which is the uppermost surface of the upper electrode plate. A touch panel having the described high durability is provided.

  According to the sixth aspect of the present invention, the high durability according to the first aspect, further comprising a seal layer covering at least the periphery of the side end portion of the upper electrode plate and the vicinity of the side end portion of the lower electrode plate. Provided is a touch panel.

  Since the highly durable touch panel of the present invention is configured as described above, the following effects can be obtained.

That is, in a touch panel having a circularly polarized antireflection filter, the upper electrode plate is a polarizing optically isotropic heat-resistant transparent resin plate having a glass transition temperature of 150 ° C. or more and a thickness of 0.15 to 0.8 mm. Between the plate 10 and the quarter-wave plate 9, the heat-resistant transparent resin plate is directly bonded to the quarter-wave plate directly on the entire surface. Even in a high temperature environment exceeding 70 ° C. as in the car when the window is closed, the quarter-wave plate and the polarizing plate are hardly suppressed in thermal expansion, and a stable state in which no swell or distortion occurs is maintained. it can. In addition, since the heat-resistant transparent resin plate is directly bonded to the ¼ wavelength plate, the stress applied to the ¼ wavelength plate is dispersed even in the high temperature environment as in the case of the glass plate, and retardation is achieved. Can cause little change. That is, the antireflection characteristic is hardly impaired.

  In addition, since the heat-resistant transparent resin plate is more flexible than the glass plate, input with a pen or a finger becomes light, and a comfortable input operation can be performed.

  In addition, by having a heat-resistant transparent resin plate with a water absorption rate of 1.3% or less, the heat-resistant transparent resin plate is less susceptible to the influence of moisture that has entered through the polarizing plate, so that the heat-resistant transparent resin plate is less likely to be deformed. The stress can be maintained against the expansion and deformation of the plate, and the upper electrode plate does not come into contact with the lower electrode plate, so that the performance of the touch panel is not impaired. Here, the reason why the water absorption rate of the heat-resistant transparent resin plate is 1.3% or less is that if the water absorption rate of the heat-resistant transparent resin plate exceeds 1.3%, it penetrates from the moisture or side surface that has entered through the polarizing plate. The heat-resistant transparent resin plate may be deformed by the moisture, and if the heat-resistant transparent resin plate is deformed, the polarizing plate or the quarter wavelength plate cannot be held by the heat-resistant transparent resin plate. It is. For the above reason, the upper electrode plate is also deformed together with the heat-resistant transparent resin plate, and the upper electrode plate may come into contact with the lower electrode plate to cause insulation failure. On the other hand, by making the water absorption of the heat-resistant transparent resin plate 1.3% or less, even if some deformation occurs in the heat-resistant transparent resin plate, the upper electrode plate is not so in contact with the lower electrode plate, There is no problem with the performance of the touch panel.

  Furthermore, the water absorption rate of the heat-resistant transparent resin plate is more preferably 1% or less of the above 1.3% or less. The reason is that by setting the water absorption rate to 1% or less, the heat-resistant transparent resin plate is hardly deformed by moisture that has penetrated through the polarizing plate or moisture that has entered from the side surface. This is because the heat-resistant transparent resin plate can be held more reliably.

  On the other hand, conventionally, since there is no such heat-resistant transparent resin plate, when the polarizing plate absorbs water, the polarizing plate is deformed due to water absorption, and the quarter-wave plate is not able to keep up with the stress, and the upper electrode plate May also be deformed, and as a result, color unevenness due to a change in retardation may occur. In addition, the deformed upper electrode plate is brought into contact with the lower electrode plate, resulting in an insulation failure. Such a problem can be solved according to the present invention.

  In addition, since the heat-resistant transparent resin plate is unlikely to be broken unlike a thin glass plate, handling at the time of assembling the touch panel becomes very easy, and there is no fear that the glass is broken during the touch panel input operation.

  It is to be noted that, by appropriately combining arbitrary embodiments of the various embodiments described above, the effects possessed by them can be produced. Although the present invention has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various variations and modifications will be apparent to those skilled in the art. Such changes and modifications are to be understood as being included therein, so long as they do not depart from the scope of the present invention according to the appended claims.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 3 is a cross-sectional view showing a highly durable low-reflection touch panel according to the first embodiment of the present invention. In the figure, 1 is an upper electrode plate, 2 is an upper electrode, 3 is a lower electrode plate, 4 is a lower electrode, 5 is an adhesive layer such as double-sided adhesive tape as an example, 6 is an air layer, 7 is a spacer, and 8 is heat-resistant and transparent. A resin plate, 9 is a quarter wavelength plate, and 10 is a polarizing plate.

The structure of the touch panel includes an upper electrode plate 1 having an upper electrode 2 made of a transparent conductive film on the lower surface and a lower electrode plate 3 having a lower electrode 4 made of a transparent conductive film on the upper surface. Basically, both electrodes 1 and 3 face each other through the air layer 6 and are bonded and fixed only outside the display region. In the case of a circularly polarized low reflection touch panel, the upper electrode 2 is used as the upper electrode 2. A layer formed by laminating at least a quarter-wave plate 9 and a polarizing plate 10 having an optical axis and an absorption axis of 45 ° or 135 ° of the quarter-wave plate 9 in this order from the side is used. Further, each of the upper electrode plate 1 and the lower electrode plate 3 is constituted by a single layer or a plurality of layers laminated by whole surface adhesion. A feature of the first embodiment of the present invention is that, in such a low reflection touch panel, the upper electrode plate 1 has an optical isotropy of 0.15 to 0.8 mm in thickness with a glass transition temperature of 150 ° C. or higher. The heat-resistant transparent resin plate 8 is provided between the polarizing plate and the quarter-wave plate, and the heat-resistant transparent resin plate 8 is directly bonded to the quarter-wave plate 9 on the entire surface ( (See FIG. 3) In each embodiment of the present invention, the “plate” includes thin sheets such as sheets and films.

  The quarter-wave plate 9 has a function of changing linearly polarized light into circularly polarized light or substantially circularly polarized light by giving a temporal phase shift (phase difference) to two orthogonally polarized light components obtained by decomposing the linearly polarized light. The phase of one polarization component is delayed by ¼ wavelength from the other polarization component. The quarter wavelength is relative to the central wavelength (about 550 nm) in the visible light region (about 400 nm to 700 nm). As the quarter-wave plate 9, a transparent resin plate such as polycarbonate, polyarylate, polyethersulfone, polysulfone, or norbornene resin is uniaxially stretched, and the refractive index in the x direction that is the stretch direction (optical axis direction). And the refractive index in the y direction perpendicular to the x direction and the refractive index in the thickness direction, that is, the z direction perpendicular to the x direction and the y direction are used.

  The quarter-wave plate 9 is combined with the polarizing plate 10 on the upper surface thereof to form a circularly polarizing type antireflection filter. Light from the outside such as an indoor fluorescent lamp or outdoor light becomes linearly polarized light through the polarizing plate 10 and becomes circularly polarized light by passing through the quarter-wave plate 9, but even if reflected by the transparent conductive film, Since the circularly polarized light passes through the quarter wavelength plate 9 again and becomes linearly polarized light perpendicular to the transmission axis of the polarizing plate 10, reflected light is suppressed. Note that the quarter wave plate 9 is flexible so as to facilitate input with a pen or a finger.

  The absorption axis of the polarizing plate 10 disposed on the upper surface of the quarter wavelength plate 9 is formed to be 45 ° or 135 ° with the optical axis 7 of the quarter wavelength plate 9. As the polarizing plate 10, generally used is a polyvinyl alcohol plate impregnated with a dichroic dye such as iodine or a dye and stretched, and coated on both sides with a cellulose or acrylic protective film.

  The quarter-wave plate 9 and the heat-resistant transparent resin plate 8 may be bonded directly on the entire surface (see FIG. 3) or indirectly bonded via an optically isotropic transparent resin plate. May be. Examples of the adhesive used for the bonding include acrylic resins such as acrylic ester copolymers, urethane resins, silicon resins, rubber resins, water-based, or UV-curing adhesives. Further, as the material of the optically isotropic transparent resin plate, a material having excellent transparency such as polycarbonate, polyarylate, polyethersulfone, polysulfone, or norbornene resin is desirable. In the above embodiment of the present invention, the optical isotropy refers to a retardation value of 10 nm or less, preferably 5 nm or less.

  Examples of the material of the heat-resistant transparent resin plate 8 include polycarbonate resin, norbornene resin, epoxy resin, siloxane resin, polyarylate resin, polyethersulfone resin, polysulfone resin, or ultraviolet curable acrylic resin or epoxy acrylic resin. Among the optically isotropic transparent resins such as heat-resistant acrylic resins, those having a glass transition temperature of 150 ° C. or higher are molded to a thickness of 0.15 to 0.8 mm.

  The heat-resistant transparent resin plate 8 of the above-described embodiment of the present invention is directly exposed to summer in the same manner as a glass plate by being bonded to the quarter wavelength plate 9 and the polarizing plate 10 as one constituent layer of the upper electrode plate 1. The quarter-wave plate 9 and the polarizing plate in a high temperature environment exceeding 70 ° C. as in a car when the window is closed under sunlight, or in a high temperature and high humidity environment where the humidity exceeds 80% such as on a rainy day The thermal expansion of 10 is almost suppressed, and a stable state in which no swell or distortion occurs is maintained. Therefore, a material that does not cause deformation due to heat even in the high temperature or high humidity environment is required. If the index is a glass transition temperature and a water absorption rate, and the glass transition temperature is 150 ° C. or higher and the water absorption rate is 1.3% or less, an optically isotropic transparent resin plate, the heat resistant transparency of each embodiment of the present invention. It can be used as the resin plate 8. More preferably, the heat-resistant transparent resin plate 8 having a glass transition temperature of 170 ° C. or higher is used. Here, the reason why the water absorption rate of the heat resistant transparent resin plate 8 is 1.3% or less is that when the water absorption rate of the heat resistant transparent resin plate 8 exceeds 1.3%, There is a possibility that the heat-resistant transparent resin plate 8 may be deformed by moisture that has entered from the side surface. If the heat-resistant transparent resin plate 8 is deformed, the polarizing plate 10 or the quarter-wave plate 9 is replaced with the heat-resistant transparent resin plate 8. It is because it cannot be held by. For the above reason, the upper electrode plate is also deformed together with the heat-resistant transparent resin plate 8, and the upper electrode plate may come into contact with the lower electrode plate to cause insulation failure. On the other hand, by setting the water absorption rate of the heat resistant transparent resin plate 8 to 1.3% or less, the upper electrode plate 1 comes into contact with the lower electrode plate 3 even if some deformation occurs in the heat resistant transparent resin plate 8. Therefore, there is no problem in the performance of the touch panel.

  Furthermore, the water absorption rate of the heat-resistant transparent resin plate 8 is more preferably 1% or less of the above 1.3% or less. The reason is that by setting the water absorption rate to 1% or less, the heat-resistant transparent resin plate 8 hardly deforms due to moisture that has entered through the polarizing plate 10 or moisture that has entered from the side surface, and the polarizing plate 10 or 1/4. This is because the wave plate 9 can be more reliably held by the heat-resistant transparent resin plate 8.

  On the other hand, conventionally, since there is no such heat-resistant transparent resin plate, when the polarizing plate absorbs water, the polarizing plate is deformed due to water absorption, and the quarter-wave plate is not able to keep up with the stress, and the upper electrode plate May also be deformed, and as a result, color unevenness due to a change in retardation may occur. In addition, the deformed upper electrode plate is brought into contact with the lower electrode plate, resulting in an insulation failure.

  On the other hand, in the present embodiment, as described above, the heat-resistant transparent resin plate 8 has the effect of moisture entering through the polarizing plate 10 by disposing the heat-resistant transparent resin plate 8 having a water absorption rate of 1.3% or less. Since the heat-resistant transparent resin plate 8 is less likely to be deformed because it is less susceptible to deformation, the stress can be maintained against the expansion and deformation of the polarizing plate 10, and the upper electrode plate 1 may be in contact with the lower electrode plate 3. As a result, the touch panel performance is not impaired.

  Further, in order to keep the quarter-wave plate 9 and the polarizing plate 10 in a stable state in which no undulation or distortion occurs, the thickness of the heat-resistant transparent resin plate 8 needs to be 0.15 mm or more. If the thickness is less than 0.15 mm even if the glass transition temperature is 150 ° C. or higher, the heat-resistant transparent resin plate 8 itself will not be deformed by heat, but the quarter-wave plate 9 and the polarizing plate 10 will be deformed. It is because it cannot withstand the power to do. More preferably, a heat-resistant transparent resin plate 8 having a thickness of 0.2 mm or more is used.

  Moreover, since the heat-resistant transparent resin plate 8 of each embodiment of the present invention has a higher flexibility than the glass plate if the thickness is set to 0.8 mm or less, it is used as a constituent layer of the upper electrode plate 1. Even if it is incorporated, the input with a pen or finger can be performed lightly. More preferably, a heat-resistant transparent resin plate 8 having a thickness of 0.7 mm or less is used. Moreover, unlike the glass plate, it is not broken, so that handling during assembly of the touch panel becomes very easy and there is no possibility of breakage during touch panel input operation. Moreover, roll processing is also possible, and defoaming treatment at the time of bonding can be easily performed.

  Table 1 below shows the amount of deflection when a heat-resistant transparent resin plate A to C having a size of 130 mm × 100 mm and a glass transition temperature of 195 ° C. and a glass plate are placed with a steel ball of φ20 mm in the center of the upper surface and pressed. It is shown.

  The heat-resistant transparent resin plate A and glass plate having the same thickness have a three-fold difference in the amount of deflection under the same static pressure condition. Further, the glass plate having a thickness of 0.2 mm has a small amount of bending even when compared with the heat-resistant transparent resin plate C having a thickness up to the upper limit of 0.8 mm. Must be set to less than 0.2 mm, and as a result, it becomes very easy to break.

  As a material of the transparent conductive film provided as the upper electrode 2 on the lower surface of the upper electrode plate 1 as described above, a metal oxide such as tin oxide, indium oxide, antimony oxide, zinc oxide, cadmium oxide, or ITO, A thin film of a metal such as gold, silver, copper, tin, nickel, aluminum, or palladium is used. As a method for forming the transparent conductive film on the upper electrode plate 1, a vacuum deposition method, a sputtering method, an ion plating method, a CVD method, or the like is used. The same applies to the transparent conductive film provided as the lower electrode 4 on the upper surface of the lower electrode plate 3.

  Next, the lower electrode plate 3 will be described. The lower electrode plate 3 is composed of a single layer or a plurality of layers laminated by whole surface adhesion. For example, in addition to the above-described optically isotropic transparent resin plate, a glass plate or a laminate thereof can be used. When the display is an LCD, if only one quarter-wave plate 9 is used, the linearly polarized light that is incident from the LCD side for display is also changed to circularly polarized light. The quarter wavelength plate 9 and a quarter wavelength plate whose optical axes are orthogonal to each other are arranged in the lower electrode plate 3 to cancel the phase. In this case, the lower electrode plate 3 may be constituted by a single quarter-wave plate single layer, or the lower electrode plate 3 may be constituted by a laminate of an optically isotropic transparent resin plate or a glass plate. Even when the display is an LCD, if a second quarter-wave plate is provided on the surface of the LCD, the second quarter of the lower electrode plate 3 of the touch panel according to the embodiment of the present invention is used. The wave plate may not be provided.

Further, the upper electrode plate 1 provided with the upper electrode 2 and the lower electrode plate 3 provided with the lower electrode 4 are usually only outside the display region by an adhesive layer 5 such as a double-sided adhesive tape or a transparent adhesive material. The air layer 6 is left in the display area. In this case, the quarter-wave plate 9 is bonded and fixed to the lower electrode plate 3 directly or indirectly via the optically isotropic transparent resin plate only outside the display area. In order to maintain the antireflection characteristic, it is necessary to prevent stress from being applied only to the peripheral portion of the quarter-wave plate 9 in a high temperature environment. In the embodiment of the present invention, the upper electrode plate 1 has the heat-resistant transparent resin plate 8 described above, and the heat-resistant transparent resin plate 8 is directly bonded to the quarter-wave plate 9 over the entire surface. Therefore, it is possible to disperse the stress applied to the quarter-wave plate 9 and hardly cause retardation change. That is, the antireflection characteristic is hardly impaired.

  In addition, when the area of the touch panel is large, the upper electrode plate 1 provided with the upper electrode 2 is prevented from contacting the lower electrode plate 3 provided with the lower electrode 4 by its own weight. Fine dot-like spacers 7 are formed on either surface. The spacer 7 can be obtained by forming a transparent photocurable resin into fine dots by a photo process. Also, the spacer 7 can be formed by forming a large number of fine dots by a printing method.

  Further, the upper surface of the polarizing plate 10 that is the uppermost surface of the upper electrode plate 1 can be subjected to low reflection treatment, antifouling treatment, and satin treatment. Alternatively, the film subjected to these treatments may be bonded to the polarizing plate 10 via an adhesive or the like as a satin layer with a low reflection / antifouling function. Here, examples of the low reflection treatment include applying a low reflection material using a fluorine resin, a silicon resin, or the like, or forming a metal multilayer film by a vacuum deposition method, a sputtering method, or the like. The film is desired to have moisture resistance. For example, the satin layer 20 with moisture-proof, low-reflection, and antifouling functions is preferably formed on the polarizing plate 10 using a PET (polyethylene terephthalate) film having a thickness of 40 μm to 80 μm. Since the PET film is excellent in moisture resistance, it is possible to prevent moisture from entering the upper electrode plate 1 by pasting it on the upper surface of the polarizing plate 10. It is also possible to use a PET film that has been subjected to heat treatment in advance to reduce shrinkage. Examples of the antifouling treatment include applying an antifouling material using a fluororesin or the like. Examples of the satin finish include sandblasting, embossing, mat coating, or etching.

  In the present invention, the heat-resistant transparent resin plate 8 serves as a support plate for each optical plate by disposing the heat-resistant transparent resin plate 8 between the polarizing plate 10 and the quarter-wave plate 9 as shown in FIG. Therefore, the expansion of the polarizing plate 10 and the quarter-wave plate 9 is suppressed even in a high-temperature and high-humidity environment, and it is difficult for changes in retardation and optical characteristics to occur. On the other hand, in the forms of FIGS. 1 and 2, since the polarizing plate 10 and the quarter-wave plate 9 are directly bonded, undulation and distortion are likely to occur compared to the configuration of FIG.

  Furthermore, as another embodiment of the present invention, as shown in FIG. 8, when the upper electrode plate 1 and the lower electrode plate 3 have substantially the same shape, the periphery of the side end portions of the upper electrode plate 1 and the lower electrode plate 3 is used. The sealing layer 21 may be formed by applying a sealing material so as to cover the surface. As another embodiment of the present invention, as shown in FIG. 9, when the upper electrode plate 1 is smaller than the lower electrode plate 3, the periphery of the upper electrode plate 1 and the edge of the lower electrode plate 3 are surrounded. The sealing layer 22 may be formed by applying a sealing material so as to cover it. As the kind of the sealing material, a UV curable resin, a heat / UV combined curable resin, an acrylic, epoxy, urethane, or silicon thermosetting resin is preferable. An example of the sealing method is a dispensing method. Thus, the sealing layers 21 and 22 can prevent moisture from entering from the end of the upper electrode plate 1 and the like, and can prevent deterioration of the adhesive layer 5 such as a double-sided adhesive tape or a transparent adhesive material. . Even if the adhesive layer 5 such as a double-sided adhesive tape or a transparent adhesive material that adheres the upper electrode plate 1 and the lower electrode plate 3 is peeled off, the sealing layers 21 and 22 are not affected even in a high temperature and high humidity environment. The touch panel characteristics are not impaired.

According to each said embodiment, in the touchscreen which has a circularly polarized light type antireflection filter, the upper electrode plate 1 is optical isotropy of thickness 0.15-0.8mm which has the characteristic that a glass transition temperature is 150 degreeC or more. Since the heat-resistant transparent resin plate 8 is directly bonded to the quarter-wave plate 9 on the entire surface, the window is closed under direct sunlight in summer like the glass plate. The thermal expansion of the quarter-wave plate 9 and the polarizing plate 10 can be almost suppressed even in a high temperature environment exceeding 70 ° C. as in a car at the time, and a stable state in which no swell or distortion occurs is maintained. be able to. Further, since the heat-resistant transparent resin plate 8 is directly bonded to the quarter-wave plate 9 over the entire surface, the stress applied to the quarter-wave plate 9 is dispersed even in the high-temperature environment as in the case of the glass plate. However, the retardation change can be hardly caused. That is, the antireflection characteristic is hardly impaired.

  Therefore, even if left in a high temperature environment for a long time, the anti-reflection properties will not deteriorate due to deformation of the external appearance and retardation change, comfortable input operation can be performed, and high durability with good workability during assembly. Have.

  Furthermore, since the heat-resistant transparent resin plate 8 is more flexible than the glass plate, the input with a pen or a finger becomes light and a comfortable input operation can be performed.

  Further, unlike the thin glass plate, the heat-resistant transparent resin plate 8 is not easily broken, so that handling at the time of assembling the touch panel becomes very easy, and there is no possibility that the glass is broken during the touch panel input operation.

  Furthermore, even if left in a high temperature environment for a long time, the anti-reflection properties are not deteriorated due to deformation of the external shape or retardation change, and comfortable input operation can be performed, and high durability with good workability during assembly is also achieved. Have.

It is sectional drawing which shows the low reflection touch panel by which a heat-resistant transparent resin plate is arrange | positioned under the quarter wavelength plate. It is sectional drawing which shows the low reflection touch panel with which a heat-resistant transparent resin board is arrange | positioned above a polarizing plate. It is sectional drawing which shows the low-reflection touch panel which has high durability based on 1st Embodiment of this invention. It is sectional drawing which shows the low reflection touch panel which concerns on a prior art. FIG. 5 is an exploded plan view showing a change in a high temperature environment for the upper electrode plate of the low reflection touch panel of FIG. 4. FIG. 5 is a cross-sectional view showing stress applied to the upper electrode plate in a high temperature environment for the low reflection touch panel of FIG. 4. It is sectional drawing which shows the low-reflection touch panel which has the high durability based on a prior art. It is sectional drawing which shows the low-reflection touch panel which has high durability which concerns on other embodiment of this invention. It is sectional drawing which shows the low-reflection touch panel which has high durability based on further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper electrode plate 2 Upper electrode 3 Lower electrode plate 4 Lower electrode 5 Adhesive layer, such as a double-sided adhesive tape, as an example 6 Air layer 7 Spacer 8 Heat-resistant transparent resin plate 9 1/4 wavelength plate 10 Polarizing plate

Claims (6)

An upper electrode plate having an upper electrode made of a transparent conductive film on the lower surface and a lower electrode plate having a lower electrode made of a transparent conductive film on the upper surface, both electrodes facing each other through an air layer. The upper electrode plate is a quarter-wave plate in order from the upper electrode side, and the polarizing plate whose optical axis and absorption axis are 45 ° or 135 ° in order from the upper electrode side. In a touch panel formed by laminating at least
The upper electrode plate is an optically isotropic heat resistant transparent resin plate having a thickness of 0.15 to 0.8 mm having a glass transition temperature of 150 ° C. or more and a water absorption of 1.3% or less. A touch panel having high durability, which is provided between a quarter-wave plate and the heat-resistant transparent resin plate is directly bonded to the whole quarter-wave plate. The touch panel having high durability according to claim 1, wherein a glass transition temperature of the heat-resistant transparent resin plate is 170 ° C. or higher. The touch panel having high durability according to claim 1, wherein the heat-resistant transparent resin plate has a thickness of 0.2 to 0.7 mm. The touch panel having high durability according to claim 1, wherein the heat-resistant transparent resin plate has a water absorption rate of 1% or less. The touch panel having high durability according to claim 1, wherein a moisture-proof PET film is disposed as a satin layer with a low reflection / antifouling function on the upper surface of the polarizing plate which is the uppermost surface of the upper electrode plate. The touch panel having high durability according to claim 1, further comprising a seal layer covering at least the periphery of the side end portion of the upper electrode plate and the vicinity of the side end portion of the lower electrode plate.

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