JP5330929B2 - Touch panel - Google Patents

Description

  The present invention relates to a touch panel that can be used outdoors where the outside light is strong, or in a high temperature, high humidity, or low temperature environment.

  The touch panel, for example, forms a resistance film on the opposing surface of the lower planar member (non-flexible glass plate or resin plate) and the upper planar member (flexible transparent resin film), and the upper planar member And the lower planar member are arranged so as to face each other at a constant interval via a spacer.

  When the surface of the upper planar member is pressed with an input pen or the like, the upper and lower resistive films arranged opposite to each other with a certain gap come into contact at the pressed part, and the resistance between the electrodes connected to the respective resistive films The value fluctuates. By detecting this resistance value, position information on the pressed position can be obtained.

  A resistance film type touch panel as such an input terminal has been required to have an added value that has not been achieved with the expansion of applications. In particular, when combined with a liquid crystal display panel and used in a device used outdoors such as a car navigation device, a portable personal computer, and a mobile phone, the liquid crystal display panel is reflected by reflection of external light on the touch panel. In order to prevent the visibility of the display content from being lowered, a polarizing film is laminated on the surface of the upper planar member to provide antiglare properties.

  Regarding the improvement of such a resistive film type touch panel, for example, Patent Documents 1 and 2 describe an improvement technique (details will be described later).

Japanese Patent No. 3590530 Japanese Patent No. 3779515

  The polarizing film laminated on the surface of the upper planar member is usually a laminate of a PVA (polyvinyl alcohol) resin film and a TAC (triacetyl cellulose) resin film. These resin films have a thermal expansion coefficient. The moisture absorption rate is large.

  A glass plate or a resin plate is used as a non-flexible support constituting the lower planar member. The glass plate has good optical properties, but is heavy and easily broken, and has a large thermal expansion coefficient from other resin materials. The resin plate is light and difficult to break. A polycarbonate resin plate or an acrylic resin plate is used as the resin plate. Polycarbonate resin has low hygroscopicity, but has birefringence, and therefore has an adverse effect on the image of the liquid crystal display panel. Since the acrylic resin plate does not have birefringence, the image of the liquid crystal display panel is not adversely affected, but the expansion and contraction due to changes in temperature and humidity are large.

  When an acrylic resin plate is used as a support constituting the lower planar member, a difference in expansion and contraction occurs between the lower planar member and the upper planar member due to changes in temperature and humidity. Swells or the lower planar member warps or dents. As a result, malfunction of the touch panel and input failure may occur.

  Generally, when the upper planar member swells longer than the lower planar member, if a bulge of 0.4 mm or more occurs, it is considered that the input is uncomfortable. The bulge of 0.4 mm means that when the original distance between the upper planar member and the lower planar member is H, a place where the actual distance is H + 0.4 mm (usually the center part of the touch panel) is generated. .

In Table 1, when the diagonal length of the lower planar member is L ₀ and the diagonal length of the upper planar member is L (L ₀ <L), the swelling of the upper planar member is 0.4 mm. The ratio of the diagonal length of the lower planar member and the diagonal length of the upper planar member,
ΔX = [(L−L ₀ ) / L ₀ ] × 100 (%)
The calculated value of is shown.

  As can be seen from Table 1, ΔX is as small as 0.01240% even when the diagonal length is 25.4 mm (1 inch), but ΔX is 0 when the diagonal length is 355.6 mm (14 inches). 0.00006%, which is extremely small. That is, when the diagonal length is as large as 355.6 mm (14 inches), the difference in expansion and contraction between the upper planar member and the lower planar member is hardly allowed.

  If there is a difference in the expansion due to temperature and humidity of the material of the upper and lower planar members, the upper planar member including the polarizing film will be entirely in relation to the lower planar member as the temperature and humidity change. As a result, the appearance of the touch panel becomes poor, and the pressing force necessary for the operation of the touch panel increases, resulting in a decrease in operability.

  Recently, the touch panel has been enlarged along with the liquid crystal display panel, so that even if there is a slight difference in expansion due to temperature and humidity between the materials of the upper and lower planar members, the floating of the upper planar member becomes a problem. .

  In order to solve the problem of expansion and contraction of the upper planar member and the lower planar member due to temperature change, in Patent Document 1, a resin having a small difference in thermal expansion coefficient is selected.

  Patent Document 2 discloses a configuration in which a swelling prevention resin film having a smaller thermal expansion coefficient than that of the polarizing film is laminated on the surface of the polarizing film to suppress the swelling of the polarizing film. A reinforcing member that balances shrinkage at low temperatures is disclosed.

  In the touch panel of Patent Document 2, a PET (polyethylene terephthalate) film was used as the swelling prevention resin film. Even if the polarizing film tried to expand as the temperature increased, the expansion was prevented by the expansion preventing resin film, and the operability of the touch panel was maintained well.

  In the touch panel of Patent Document 2, the support plate of the lower planar member is a glass plate. However, as described above, the support plate is preferably an acrylic resin plate because of its lightness and resistance to cracking. However, it has been found that when the support plate of the lower planar member is changed to an acrylic resin plate, expansion and contraction due to humidity change is unavoidable even if expansion and contraction due to temperature change is avoided by means of Patent Document 2.

  Specifically, the deformation of the acrylic resin plate due to high temperature and high humidity is large, and even if the high temperature and high humidity returns to normal temperature and humidity, the adhesive used for the upper and lower planar members is deformed. It was found that the distortion of the touch panel does not return because it is fixed in the fixed state. In this case, the acrylic resin plate was deformed by high humidity even at room temperature, but since the deformation of the adhesive was slow at room temperature, it was tested in a high temperature and high humidity state in order to accelerate the change.

  Since a portable device equipped with a touch panel is easy to carry, it is impossible to predict in which environment it will be used. The touch panel can be used under high temperature and high humidity indoors in automobiles in summer, or at low temperatures outside in cold regions, so the touch panel does not deform even in such a harsh environment, ensuring good operability. It is necessary.

  When the support plate of the lower planar member is an acrylic resin plate, the shape deterioration of the touch panel accompanying the change in temperature and humidity is the same even if a resin film having a high coefficient of thermal expansion other than the polarizing film is laminated on the upper planar member. Arise.

  The present invention has been made to solve the above-described problems. When an acrylic resin plate is used as the support plate for the lower planar member, the shape change is small even in a high-temperature and high-humidity environment, and the operability is deteriorated. It is an object to provide a touch panel that does not have any.

The gist of the present invention is as follows.
(1) The touch panel of the present invention has an upper planar member including, in this order, a bulge prevention film, a polarizing film, and an upper electrode film having a transparent resistance film formed on the lower main surface, and a transparent resistance film formed on the upper main surface. A lower electrode member comprising a lower electrode film comprising a cyclic polyolefin resin film having optical anisotropy, an acrylic resin plate, and a moisture-proof film comprising a cyclic polyolefin resin film having optical isotropy in this order; Is a touch panel in which the upper electrode film and the lower electrode film are opposed to each other at a constant interval. The upper electrode film and the lower electrode film are both λ / 4 retardation films, and the slow axes of the λ / 4 retardation films are orthogonal to each other.
( 2 ) In the touch panel of the present invention, the swelling prevention film is a PET (polyethylene terephthalate) film.

  An upper electrode film (λ / 4 retardation film) and a lower electrode film (λ / 4 retardation film) having a resistance film formed on the surface are arranged so that their slow axes are orthogonal to each other, and polarized on the upper electrode film. By laminating a film and a bulge-preventing film and laminating an acrylic resin plate (support plate) and a moisture-proof film (cyclic polyolefin-based resin film) on the lower electrode film, a touch panel with little deformation can be obtained even in a high-temperature and high-humidity environment.

The perspective view of one Example of the touchscreen of this invention Exploded view of one embodiment of the touch panel of the present invention Sectional drawing which shows the laminated structure of the touchscreen of this invention Schematic showing typical deformation pattern of touch panel Sectional view showing the laminated structure of a transmissive capacitive touch panel

  Hereinafter, embodiments of the touch panel of the present invention will be described with reference to the drawings.

[Overall configuration of touch panel]
FIG. 1 is a perspective view of an embodiment of a touch panel 100 of the present invention. As shown in FIG. 1, the touch panel 100 of the present invention is configured by laminating an upper planar member 110 and a lower planar member 130 via a spacer 140. The upper planar member 110 is a transparent and flexible planar member on the side that receives input from an operator using a finger or an input pen, and a plurality of resin films are laminated as will be described later. Composed. The connector 120 is connected to internal electrodes.

  FIG. 2 is an exploded view of the touch panel 100 of FIG. As shown in FIG. 2, the spacer 140 is formed in a continuous frame shape except for a portion where the connector 120 is mounted and a corner cutout 141 on the opposite side, and the material is PET (polyethylene terephthalate). ) Film etc. are used.

  Adhesive is applied to both surfaces of the spacer 140, and the upper planar member 110 and the lower planar member 130 are adhered at the peripheral edge thereof. In the cut portion 141, since there is no spacer, a gap is formed between the upper planar member 110 and the lower planar member 130, but this is used as an internal air vent hole.

  That is, as the temperature changes, the air between the upper planar member 110 and the lower planar member 130 expands and contracts, but the air circulates to the outside through the cut portion 141 (air vent hole). As a result, the internal pressure and the external pressure can always be made equal, so that there is no inconvenience that the internal pressure becomes higher than the external pressure due to the thermal expansion of the internal air and the operability is deteriorated.

  As the touch panel 100 becomes larger in size, the capacity of the internal space increases, and the amount of air that enters and exits as the temperature changes increases. In this case, the spacer 140 is partly cut at another corner portion to increase the number of air vent holes.

  In the gap between the upper planar member 110 and the lower planar member 130 inside the spacer 140, dot spacers 160 are provided at a predetermined interval, and in cooperation with the frame spacer 140, The distance between the opposing surfaces of the planar member 110 and the lower planar member 130 is maintained approximately uniformly at about 100 μm.

  On the main surface of the upper planar member 110 facing the lower planar member 130, a resistance film 111 made of ITO (indium tin oxide) is formed on substantially the entire surface by sputtering or the like. Is formed. In addition, electrodes 112 are provided on two opposing sides of the resistance film 111.

  A pair of electrode end portions 114 for connecting to the pair of connection electrodes 122 of the connector 120 are formed on the main surface of the upper planar member 110. A wiring pattern 113 connects the electrode end portion 114 and the electrode 112 provided on the two sides of the resistance film 111.

  The lower planar member 130 is made of a resin plate and a thin resin film (details will be described later). On the main surface on the side facing the upper planar member 110, a resistive film 131 made of ITO is applied to substantially the entire surface by sputtering or the like. Is provided.

  Electrodes 132 are formed on the two opposite sides of the resistance film 131 and on the two sides where the electrode 112 formed on the upper resistance film 111 is not present. A pair of electrode end portions 134 connected to the pair of connection electrodes 123 of the connector 120 are formed on the main surface of the resistance film 131. Further, a wiring pattern 133 that connects the electrode end portion 134 and the electrode 132 provided on the two sides of the resistance film 131 is formed.

  The connector 120 is one end of a connection cable 190 formed by sandwiching four flexible wires 129 made of silver or copper into a film material made of PET (polyethylene terephthalate) or polyimide. The connector 120 exposes the connection electrode 122 connected to the electrode end 114 of the upper planar member 110 on the upper surface, and connects the connection electrode 123 connected to the electrode end 134 of the lower planar member 130 to the lower surface. The exposed end of the flexible wire 129 is connected to the connection electrodes 122 and 123.

  If the four flexible wires 129 and the four connection electrodes 122 and 123 are not divided into one connector 120, the cost can be suppressed in terms of both material costs and man-hours.

  In a state where the touch panel 100 is assembled, the upper connection electrode 122 is bonded to the upper electrode end 114, and the lower connection electrode 123 is bonded to the lower electrode end 134. This adhesion is performed by applying a conductive paste in which carbon is kneaded to silver, which is a common material for the end portions of the electrodes, to the adhesion portion and thermocompression bonding.

  In addition, a notch 121 is provided between the upper and lower connection electrodes 122 and 123 of the connector 120 so as to eliminate the stress caused by the difference in thermal expansion coefficient between the upper planar member 110 and the lower planar member 130. ing. That is, when the temperature rises, the upper planar member 110 and the lower planar member 130 expand, but by providing the notch 121, the difference between the thermal expansion amounts of the upper planar member 110 and the lower planar member 130 occurs. The stress acting on the connector 120 can be absorbed. Thereby, even if it uses in a wide temperature range, it is hard to raise | generate a contact failure and disconnection in this part.

[Laminated structure of touch panel]
FIG. 3 is a cross-sectional view showing the laminated structure of the touch panel 100 of the present invention. For convenience of explanation, the laminated structure of the liquid crystal display panel 200 to which the touch panel 100 is attached is also shown.

  As shown in FIG. 3, the upper planar member 110 is bonded to the bulge prevention film 101, the polarizing film 102, and the upper electrode film (λ / 4 retardation film) 103 in order from the outside with an adhesive (not shown). Are stacked. A resistance film 111 is formed on the upper electrode film (λ / 4 retardation film) 103. A PET (polyethylene terephthalate) film is used for the swelling prevention film 101. A hard coat layer and an antireflection layer are preferably laminated on the input side surface of the bulge prevention film 101.

  In the lower planar member 130, a lower electrode film (λ / 4 retardation film) 134 is bonded to the surface of an acrylic resin plate 135 as a support plate with an adhesive (not shown). A moisture-proof film 136 is bonded to the back surface of the acrylic resin plate 135 with an adhesive (not shown). A resistance film 131 is formed on a surface of the lower electrode film (λ / 4 retardation film) 134 facing the upper planar member 110.

  The upper planar member 110 and the lower planar member 130 are disposed to face each other with the spacer 140 interposed therebetween, and are held so that the distance between the resistive film 111 and the resistive film 131 is in an optimum state (typically 100 μm). The

  Table 2 shows the thickness, thermal expansion coefficient, saturated water absorption rate, and moisture permeability of each laminated material used in the touch panel 100 of the present invention.

  The polarizing film 102 was formed by sandwiching a stretched film of PVA (polyvinyl alcohol) resin adsorbed and oriented with a dichroic dye such as an iodine dichroic dye between two TAC (triacetyl cellulose) resin films. Is. The TAC resin film functions as a protective film for the PVA resin film.

The PVA resin film used in this example has a thickness of 20 μm, and the TAC resin film has a thickness of 55 μm (× 2 sheets). Since the thin PVA resin film extends depending on the thermal expansion of the thick TAC resin film, the thermal expansion coefficient of the polarizing film 102 is approximately equal to the thermal expansion coefficient (54 × 10 ⁻⁶ / ° C.) of the TAC resin film.

  The upper electrode film (λ / 4 retardation film) 103 is a film obtained by uniaxially stretching a norbornene resin film (Zeonor manufactured by Optes Co., Ltd.), which is a kind of cyclic polyolefin resin. Since the unstretched norbornene resin film is optically isotropic, it is uniaxially stretched to give a phase difference of λ / 4. The norbornene-based resin film is excellent in terms of transparency, surface hardness, and heat resistance, and is suitable for a touch panel.

  The moisture-proof film 136 is an unstretched norbornene resin film and is optically isotropic.

  As can be seen from Table 2, among the upper planar members 110 that are easily affected by the external environment, the polarizing film 102 has a large coefficient of thermal expansion and water absorption, and the upper electrode film 103 has a large coefficient of thermal expansion. Therefore, when the temperature and humidity rise, the upper planar member 110 expands greatly.

  Since the peripheral portions of the upper planar member 110 and the lower planar member 130 are fixed via the spacers 140, the expansion of the upper planar member 110 escapes upward and causes the upper planar member 110 to bulge. Thereby, the appearance and operability of the touch panel 100 are deteriorated.

  Therefore, a PET film having a thermal expansion coefficient smaller than that of the polarizing film 102 and the upper electrode film 103 and having a low water absorption rate and moisture permeability is used as the swelling preventing film 101 on the outermost surface of the upper planar member 110. Thereby, even in an environment of high temperature and high humidity, the upper planar member 110 does not swell so as to cause a problem.

  However, when the touch panel of this configuration (the touch panel 100 of the present invention that does not have the moisture-proof film 136) is exposed to high temperature and high humidity for a long time, in contrast to the small expansion of the upper planar member 110, It has been found that the expansion of the lower planar member 130 is increased, the surface of the touch panel is deformed so as to be recessed, and the operability is lowered.

  This is because the lower electrode film 134 constituting the lower planar member 130 has a large coefficient of thermal expansion, and the acrylic resin plate 135 has a large coefficient of thermal expansion and water absorption. In particular, the acrylic resin plate 135 expands by 0.2% or more even by water absorption.

  Therefore, a moisture-proof film 136 (norbornene resin film) having a lower water absorption rate and moisture permeability than the acrylic resin plate 135 is adhered to the entire outer surface of the acrylic resin plate 135 through an adhesive (not shown). Combined. In Example 1 of the touch panel 100 of the present invention, the thickness of the moisture-proof film 136 was 100 μm, and in Example 2, the thickness of the moisture-proof film 136 was 40 μm.

  Table 3 shows the results of the high-temperature and high-humidity test and the low-temperature test in Examples 1 and 2 of the touch panel 100 of the present invention, Comparative Example 1 without the moisture-proof film 136, and Comparative Example 2 without the moisture-proof film 136 and the swelling prevention film 101. Indicates. The material and thickness of each layer except the moisture-proof film 136 of the touch panel used for the test are the same as those shown in Table 2. The size of the touch panel is 90 mm × 55 mm (4 inches diagonal).

  In Table 3, “O”, “Δ”, and “X” indicate the swelling of the upper planar member 110 and the depression of the lower planar member 130 evaluated according to the criteria in Table 4. ○ and △ are within the standard, and × is outside the standard. When the evaluation of the swelling of the upper planar member 110 and the evaluation of the depression of the lower planar member 130 are different, the worse evaluation was adopted.

  To swell the upper planar member 110, a touch panel was placed on a surface plate, and the difference between the average surface height at the four corners of the touch panel and the height at the center of the touch panel surface was measured using a laser beam measuring device. For the dents in the lower planar member 130, the touch panel was placed on a surface plate, and the average height of the back surface of the four corners of the touch panel was measured.

  FIG. 4 is a schematic diagram showing a typical deformation pattern of the touch panel.

  In <1>, the polarizing film 102 is deformed upward and swells, but the acrylic resin plate 135 is not deformed.

  In <2>, the polarizing film 102 is deformed upward and swells, and the acrylic resin plate 135 is deformed downward and swells. This state is called that the acrylic resin plate 135 is recessed.

  In <3>, the polarizing film 102 is not deformed and the acrylic resin plate 135 is not deformed due to the effect of the swelling prevention film 101.

  In <4>, the polarizing film 102 is not deformed due to the effect of the swelling prevention film 101, but the acrylic resin plate 135 is deformed downward and swollen.

  In <5>, the polarizing film 102 is not deformed due to the effect of the swelling prevention film 101, and the acrylic resin plate 135 is not deformed due to the effect of the moisture-proof film 136.

  The evaluation subscripts <1> to <5> shown in Table 3 correspond to the deformation patterns <1> to <5> in FIG.

  It can be seen from Comparative Example 1 that when there is no moisture-proof film 136, even in a high-temperature and high-humidity environment, if there is a bulge-proof film (PET) 101, the deformation will be within the specifications for a short time. However, since the acrylic resin plate 135, which is a support for the lower planar member 130, absorbs moisture and deforms into a concave shape over a long time, a dent of 2 mm or more is generated.

  On the other hand, as can be seen from Examples 1 and 2, when the moisture-proof film 136 is attached to the back surface of the acrylic resin plate 135, moisture absorption from the back surface of the acrylic resin plate 135 can be suppressed, and the deformation falls within the standard. . In particular, when the moisture-proof film 136 having a thickness of 100 μm of Example 1 was used, even if the standing time was extended to 480 hours not shown in Table 3, the deformation was within the specifications.

  This is because the upper electrode film (λ / 4 retardation film) 103 and the lower electrode film (λ / 4 retardation film) 134 have a moisture-proof effect together with the moisture-proof film 136 attached to the back surface of the acrylic resin plate 135. This is because the humidity expansion of the resin plate 135 is suppressed.

  When the moisture-proof film 136 having a thickness of 40 μm of Example 2 was used, a dent was generated at 60 ° C., 90%, 48 hours, although it was within the standard, and the evaluation was Δ. Although not shown in Table 3, when this was extended to 480 hours, the deformation progressed, and the evaluation was out of specification x (the deformation pattern was <4> at this time).

  Since the moisture permeability of the film depends on the thickness of the film and the exposure time, it is necessary to select the thickness of the moisture-proof film 136 according to the environment in which the touch panel is used.

  As shown in FIG. 3, a transmissive liquid crystal display panel 200 is disposed below the touch panel 100 of the present invention. The liquid crystal display panel 200 has a known configuration in which a polarizing film 202 is disposed on the upper surface of the liquid crystal cell 201 and a polarizing film 203 is disposed on the lower surface. A known backlight 204 is disposed below the liquid crystal display panel 200.

  Next, in the touch panel 100 of the present invention, the visibility of the liquid crystal display panel 200 is improved by the polarizing film 102, the upper electrode film (λ / 4 retardation film) 103, and the lower electrode film (λ / 4 retardation film) 134. The principle will be explained.

  The polarizing film 102 of the touch panel 100 is disposed so that the transmission axis coincides with the polarizing film 202 of the liquid crystal display panel 200. The upper electrode film (λ / 4 retardation film) 103 is arranged so that the slow axis forms 45 ° with the transmission axis of the polarizing film 102.

  External light incident from the surface of the bulge prevention film 101 becomes linearly polarized light by the polarizing film 102 and further becomes circularly polarized light by the upper electrode film (λ / 4 retardation film) 103. This circularly polarized light is reflected by the resistance film 111, the resistance film 131, the acrylic resin plate 135, the surface of the liquid crystal display panel 200, and the like. At this time, the phase is shifted by π / 2.

  The reflected light is incident again on the upper electrode film (λ / 4 retardation film) 103 and becomes linearly polarized light, and its vibration plane is rotated by 90 ° from the vibration plane at the time of incidence. Therefore, it is absorbed by the polarizing film 102 and does not go outside.

  In this way, even if external light is incident on the touch panel 100, the internal reflected light does not come out, so that the display content of the liquid crystal display panel 200 can be clearly seen even when used outdoors with strong external light. can do.

  In addition, the slow axis of the lower electrode film (λ / 4 retardation film) 134 is arranged to form 45 ° with respect to the transmission axis of the polarizing film 202. The rotation direction of the circularly polarized light of the backlight 204 that has passed through the lower electrode film (λ / 4 retardation film) 134 is opposite to the rotation direction of the incident light that has passed through the upper electrode film (λ / 4 retardation film) 103. Thus, the lower electrode film (λ / 4 retardation film) 134 is installed.

  The light of the backlight 204 passes through the polarizing film 202 of the liquid crystal display panel 200 and becomes linearly polarized light, passes through the lower electrode film (λ / 4 retardation film) 134 and becomes circularly polarized light, and further, the upper electrode film (λ / 4 retardation film) 103 and returns to linearly polarized light.

  Since the lower electrode film (λ / 4 retardation film) 134 and the upper electrode film (λ / 4 retardation film) 103 are orthogonal to each other, the upper electrode film (λ / 4 retardation film) The plane of vibration of linearly polarized light after passing through 103 is equal to the plane of vibration of linearly polarized light immediately after passing through polarizing film 202.

  Since the polarizing film 102 and the polarizing film 202 are arranged so that the absorption axes are equal, the linearly polarized light after being emitted from the backlight 204 and passing through the upper electrode film (λ / 4 retardation film) 103 is used. The vibration surface can pass through the polarizing film 102 as it is.

  Therefore, the light emitted from the backlight 204 is emitted to the outside without being obstructed by the polarizing film 102 and the upper electrode film (λ / 4 retardation film) 103, and the backlight 204 does not become insufficient in light quantity. Sex is secured.

  The touch panel 100 of the above embodiment is a touch panel 100 configured by an upper planar member 110 and a lower planar member 130 that are both laminated with a resin base material. The touch panel 100 includes an upper electrode film (λ / 4 retardation film) 103, a lower electrode film (λ / 4 retardation film) 134, a polarizing film 102, and an acrylic film, which are arranged so that their slow axes are orthogonal to each other. A support plate made of a resin plate 135 is used. Even if this touch panel 100 is used outdoors, the visibility of the liquid crystal display panel does not deteriorate.

  FIG. 5 shows a transmissive capacitive touch panel 300 in which an upper electrode thin film 304 and a lower electrode thin film 306 are laminated via a resin dielectric layer (λ / 4 retardation film) 305. Also in the transmissive capacitive touch panel 300, the polarizing film 302, the λ / 4 retardation film 303, and the acrylic resin plate 307 are configured as supports so that the visibility of the liquid crystal display panel does not deteriorate even when used outdoors. To do. In that case, an optically isotropic cyclic polyolefin-based resin is used as the moisture-proof film 308 on the back liquid crystal display panel side of the acrylic resin plate 307. Thereby, deformation due to high temperature and high humidity of the acrylic resin plate 307 can be suppressed.

  Since a portable device equipped with a touch panel is easy to carry, it is impossible to predict in which environment it will be used. The touch panel of the present invention is not deformed even in a harsh environment such as in a hot and humid room of an automobile in summer or under a low temperature outside in a cold region, and good operability is ensured.

DESCRIPTION OF SYMBOLS 100 Touch panel 101 Swelling prevention film 102 Polarizing film 103 Upper electrode film 110 Upper planar member 111 Resistive film 112 Electrode 113 Wiring pattern 114 Electrode end 120 Connector 121 Notch 122 Connection electrode 123 Connection electrode 129 Flexible wire 130 Lower planar member 131 Resistance Film 132 Electrode 133 Wiring pattern 134 Electrode end 134 Lower electrode film 135 Acrylic resin plate 136 Moisture-proof film 140 Spacer 141 Cut-out portion 160 Dot spacer 190 Connection cable 200 Liquid crystal display panel 201 Liquid crystal cell 202 Polarizing film 203 Polarizing film 204 Backlight 300 Transmission type capacitive touch panel 301 Swelling prevention film 302 Polarizing film 303 Phase difference plate 304 Upper electrode thin film 306 Lower electricity Ultrathin film 307 Acrylic resin plate 308 Moisture-proof film

Claims (2)

An upper planar member including an swelling prevention film, a polarizing film, and an upper electrode film in which a transparent resistance film is formed on the lower main surface in this order;
A lower electrode film made of a cyclic polyolefin resin film having optical anisotropy having a transparent resistance film formed on the upper main surface, an acrylic resin plate, and a moistureproof film made of a cyclic polyolefin resin film having optical isotropy. And a lower planar member including in this order,
It is a touch panel in which the upper electrode film and the lower electrode film are opposed to each other at a constant interval by laminating via a spacer,
The upper electrode film and the lower electrode film are both λ / 4 retardation films, and the slow axes of the λ / 4 retardation films are orthogonal to each other. The touch panel according to claim 1, wherein the bulge preventing film is a PET (polyethylene terephthalate) film.

Images