JP2006011597A - Touch panel and input device using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel used for various electronic devices and an input device using this that have high visibility and allow a reliable operation. <P>SOLUTION: The touch panel is constituted by mounting a polarizing plate 7 that is heated at 85°C and has 0.4% or less of dimension contraction coefficient to the upper surface of an upper substrate 1. Even when the touch panel is used at high temperatures, the polarizing plate 7 hardly contracts, warp or the like of the touch panel is prevented, the visibility of a liquid crystal display element or the like is high, and the reliable operation is allowed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a touch panel used for operating various electronic devices and an input device using the same.

  In recent years, as various electronic devices such as mobile phones and mobile terminals have become highly functional and diversified, a light transmissive touch panel is mounted on the front surface of a display element such as a liquid crystal, and the display element on the back side is attached through this touch panel. There is an increasing number of devices that switch functions of devices by pressing a touch panel with a finger or a pen while visually recognizing the display, and there is a need for a device that is inexpensive and excellent in visibility.

  Such a conventional touch panel will be described with reference to FIG.

  In addition, in order to make the structure easy to understand, the drawing shows an enlarged dimension in the thickness direction.

  FIG. 2 is a cross-sectional view of a conventional touch panel, in which 1 is a film-shaped and light-transmissive upper substrate, 2 is a light-transmissive lower substrate, and the lower surface of the upper substrate 1 is indium tin oxide or the like. The lower conductive layer 4 is formed on the upper surface of the lower substrate 2.

  In addition, a plurality of dot spacers (not shown) are formed on the upper surface of the lower conductive layer 4 by an insulating resin at a predetermined interval, and a pair of upper electrodes (not shown) are formed at both ends of the upper conductive layer 3. At both ends of the lower conductive layer 4, a pair of lower electrodes (not shown) perpendicular to the upper electrode are formed.

  Further, reference numeral 5 denotes a frame-shaped spacer. The outer periphery of the upper substrate 1 and the lower substrate 2 is bonded to each other by an adhesive layer (not shown) formed on the upper and lower surfaces of the spacer 5 so that the upper conductive layer 3 and the lower conductive layer are bonded together. The touch panel is configured such that the layers 4 face each other with a predetermined gap.

  The touch panel configured in this manner is disposed on the front surface of a liquid crystal display element or the like and attached to an electronic device, and a pair of upper and lower electrodes are connected to an electronic circuit (not shown) of the device. .

  In the above configuration, when the upper surface of the upper substrate 1 is pressed with a finger or a pen while visually recognizing the display of the liquid crystal display element on the back of the touch panel, the upper substrate 1 is bent, and the upper conductive layer 3 at the pressed position is the lower conductive layer. Contact layer 4.

  A voltage is sequentially applied from the electronic circuit to the upper electrode and the lower electrode, and the electronic circuit detects the pressed portion by the voltage ratio between these electrodes, and the various functions of the device are switched. It was what has been.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2002-297319 A

  However, in the above conventional touch panel, the touch panel is composed of many components such as the upper substrate 1, the upper conductive layer 3 on the lower surface, and the lower conductive layer 4 and the lower substrate 2 with a gap therebetween. In a particularly bright state such as outdoors or under a fluorescent lamp, there is a problem that external light such as sunlight or light is reflected by these upper and lower surfaces, making it difficult to see the display on the back surface of the touch panel.

  In addition, in order to improve the visibility due to the reflection of such external light, a polarizing plate or the like superimposed on the upper surface of the touch panel has been proposed, but when such a touch panel is used at high temperature, There is a problem that the polarizing plate contracts, the touch panel warps due to a contraction difference between the upper substrate 1 and the spacer 5, and the contact between the upper conductive layer 3 and the lower conductive layer 4 becomes unstable.

  The present invention solves such a conventional problem, and an object of the present invention is to provide a touch panel with good visibility such as a liquid crystal display element and the like, and an input device using the same.

  In order to achieve the above object, the present invention has the following configuration.

  The invention according to claim 1 of the present invention is a touch panel configured by mounting a polarizing plate which is heat-treated at 85 ° C. or higher and has a dimensional shrinkage of 0.4% or less on the upper surface of the upper substrate. Even when used below, contraction of the polarizing plate is difficult to occur, warping of the touch panel is prevented, the visibility of the liquid crystal display element and the like is good, and a touch panel with reliable operation can be obtained.

  The invention according to claim 2 is the invention according to claim 1, wherein retardation plates are provided between the upper substrate and the polarizing plate and on the lower surface of the lower substrate, and external light is transmitted by the polarizing plate and the upper and lower retardation plates. It has an effect of preventing reflection and obtaining better visibility of the liquid crystal display element on the back surface.

  According to a third aspect of the present invention, a control circuit is connected to both ends of the upper conductive layer of the touch panel according to claim 1 and both ends of the lower conductive layer in a direction orthogonal to the upper conductive layer. The input device is configured to apply a voltage to both ends of the upper conductive layer and the lower conductive layer to detect the pressed portion, and easily realize an input device with good visibility and reliable operation. It has the effect of being able to.

  As described above, according to the present invention, it is possible to obtain an advantageous effect that a touch panel with favorable visibility and reliable operation and an input device using the touch panel can be realized.

  Hereinafter, an embodiment of the present invention will be described with reference to FIG.

  In addition, in order to make the structure easy to understand, the drawing shows an enlarged dimension in the thickness direction.

  Further, the same reference numerals are given to the same components as those described in the background art section, and the detailed description will be simplified.

(Embodiment)
FIG. 1 is a cross-sectional view of a touch panel according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an optically isotropic film such as polyethersulfone or polycarbonate, and an optically transparent upper substrate. A light-transmitting lower substrate such as a film or glass or acrylic resin. A light-transmitting upper conductive layer 3 such as indium tin oxide or tin oxide is formed on the lower surface of the upper substrate 1. The lower conductive layer 4 is formed by sputtering or the like.

  A plurality of dot spacers (not shown) are formed on the upper surface of the lower conductive layer 4 by an insulating resin such as epoxy or silicon at predetermined intervals, and a pair of upper electrodes (see FIG. However, a pair of lower electrodes (not shown) perpendicular to the upper electrode are formed at both ends of the lower conductive layer 4.

  Reference numeral 5 denotes a frame-like spacer such as a non-woven fabric or a polyester film, and the outer periphery of the upper substrate 1 and the lower substrate 2 are bonded to each other by an adhesive layer (not shown) applied and formed on the upper and lower surfaces of the spacer 5. The conductive layer 3 and the lower conductive layer 4 are opposed to each other with a predetermined gap.

  Further, 7 is a linearly polarized polarizing plate having flexibility and a dimensional shrinkage of 0.4% or less. Polyvinyl alcohol obtained by adsorbing dichroic dyes such as azo, quinone, and indigo to be uniaxially stretched and oriented. Triacetyl cellulose or the like is laminated on the upper and lower surfaces.

  Further, 8 and 9 are quarter wave flexible phase difference plates obtained by stretching a film such as polycarbonate or cycloolefin polymer to give birefringence, and the phase difference plate 8 is formed on the upper surface of the upper substrate 1. The phase difference plate 9 is affixed to the lower surface of the lower substrate 2.

  Then, a polarizing plate 7 is attached and pasted on the phase difference plate 8 on the upper surface of the upper substrate 1 with an adhesive (not shown) such as acrylic to constitute a touch panel.

  In the touch panel having the above-described configuration, first, after polarizing plate 7 having triacetyl cellulose or the like laminated on both sides such as polyvinyl alcohol is annealed at 85 ° C. for 30 minutes, A phase difference plate 8 is attached to the plate to form a circularly polarizing plate.

  Next, the upper substrate 1 and the lower substrate 2 are bonded together by the spacer 5, the polarizing plate 7 and the retardation plate 8 are bonded to the upper surface of the upper substrate 1, and the retardation plate 9 is bonded to the lower surface of the lower substrate 2 to touch the touch panel. Is produced.

  The touch panel thus manufactured is placed on the front surface of the liquid crystal display element or the like and attached to an electronic device, and both ends of the upper conductive layer 3 and the lower conductive layer 4 through a pair of upper and lower electrodes. Are connected to a control circuit (not shown) formed by electronic components such as a microcomputer to form an input device.

  In the above configuration, when the upper surface of the polarizing plate 7 is pressed with a finger or a pen while visually recognizing the display of the liquid crystal display element on the back of the touch panel, the polarizing plate 7, the retardation plate 8, and the upper substrate 1 are bent and pressed. The upper conductive layer 3 is in contact with the lower conductive layer 4.

  A voltage is sequentially applied from the control circuit to the upper electrode and the lower electrode, and the control circuit detects the pressed position by the voltage ratio between these electrodes, and the various functions of the device are switched. Has been.

  At this time, external light such as sunlight and lamps from above first passes through the polarizing plate 7, so that, for example, the polarizing plate 7 is Y in the light wave in the X direction and the Y direction orthogonal thereto. In the case where the light wave in the direction is blocked, it becomes linearly polarized light in the X direction and enters the retardation plate 8 from the polarizing plate 7.

  Next, this light passes through the retardation plate 8 having a quarter wavelength, and is reflected upward by the lower conductive layer 4 with a wavelength shifted by λ / 4 with respect to the wavelength λ of the light.

  Then, the reflected light passes through the phase difference plate 8 again, and the wavelength further shifts by λ / 4 and enters the polarizing plate 7 as linearly polarized light in the Y direction. Since only the light wave is allowed to pass, the reflected light in the Y direction is blocked by the polarizing plate 7.

  That is, external light incident on the touch panel from above is reflected upward by the lower conductive layer 4, but this reflected light is blocked by the polarizing plate 7 and is not emitted from the upper surface of the polarizing plate 7 that is the operation surface. And a good visibility of the liquid crystal display element on the back surface is obtained.

  On the other hand, if the lighting light of the liquid crystal display element or the like on the back of the touch panel is linearly polarized in the Y direction, it first passes through the phase difference plate 9 to shift the wavelength by λ / 4, and then the phase difference plate. By passing through 8, the wavelength is further shifted by λ / 4, and it becomes linearly polarized light in the X direction, enters the polarizing plate 7, and exits from the upper surface of the polarizing plate 7 that is the operation surface.

  That is, the lighting light from the liquid crystal display element or the like passes through the phase difference plate 9 and the phase difference plate 8 to become linearly polarized light in the X direction, and is emitted from the upper surface of the polarizing plate 7 just by shifting the wavelength by λ / 2. Therefore, the display of the liquid crystal display element on the back surface of the touch panel can be clearly recognized.

  Furthermore, since the polarizing plate 7 is heat-treated at 85 ° C. or more and has a dimensional shrinkage of 0.4% or less, it is difficult for the polarizing plate 7 to shrink even when the touch panel is used at a high temperature. The touch panel is configured to prevent warping or the like.

  As described above, according to the present embodiment, the polarizing plate 7 that is heat-treated at 85 ° C. or more and has a dimensional shrinkage of 0.4% or less is mounted on the upper surface of the upper substrate 1 and used at a high temperature. Even in such a case, it is difficult to cause contraction of the polarizing plate, prevent warping of the touch panel, and the like, a liquid crystal display element having good visibility, a reliable touch panel, and an input device using the same can be obtained. .

  And by laminating triacetyl cellulose or the like on both sides of polyvinyl alcohol or the like to form the polarizing plate 7, compared to what is bonded to the both sides of the polyvinyl alcohol, an arton film that is excellent in heat resistance but expensive, A touch panel can be manufactured at low cost.

  The polarizing plate 7 can also be formed using polyvinyl alcohol having iodine adsorbed, but when heat treatment is performed at 85 ° C. or higher, iodine as an atom is reduced and the polarizing property is easily deteriorated. By using polyvinyl alcohol adsorbed with a dichroic dye that is a molecule and is less reduced by heating as in the present embodiment, such polarization deterioration can be prevented.

  Further, by providing retardation plates 8 and 9 between the upper substrate 1 and the polarizing plate 7 and on the lower surface of the lower substrate 2, reflection of external light is prevented, and better visibility of the liquid crystal display element on the rear surface is obtained. be able to.

  The touch panel according to the present invention and the input device using the touch panel have an advantageous effect of providing good visibility and reliable operation, and are useful for operating various electronic devices.

Sectional drawing of the touchscreen by one embodiment of this invention Cross-sectional view of a conventional touch panel

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper substrate 2 Lower substrate 3 Upper conductive layer 4 Lower conductive layer 5 Spacer 7 Polarizing plate 8 Phase difference plate 9 Phase difference plate

Claims (3)

From an upper substrate having an upper conductive layer formed on the lower surface, a polarizing plate mounted on the upper surface of the upper substrate, and a lower substrate having a lower conductive layer facing the upper conductive layer with a predetermined gap formed on the upper surface The touch panel in which the polarizing plate is heat-treated at 85 ° C. or more and the dimensional shrinkage is 0.4% or less. The touch panel according to claim 1, wherein retardation plates are provided between the upper substrate and the polarizing plate and on the lower surface of the lower substrate. A control circuit is connected to both ends of the upper conductive layer of the touch panel according to claim 1 and both ends of the lower conductive layer in a direction orthogonal to the upper conductive layer, and the control circuit is connected to the upper conductive layer and the lower conductive layer when pressing the upper conductive layer. An input device that detects a pressed position by applying a voltage to both ends of a conductive layer.

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