JP2006011598A - Touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch panel that is used for various electronic devices, has high visibility, and is inexpensive. <P>SOLUTION: The touch panel is constituted by facing a lower conductive layer 4 of the upper surface of a lower phase difference plate 12 to an upper conductive layer 3 of the lower surface of an upper phase difference plate 11 of which upper surface is mounted with a polarizing plate 13 with a predetermined clearance. The reflection of the external light is prevented by the polarizing plate 13, the upper phase difference plate 11, and the lower phase difference plate 12, the visibility of a liquid crystal display element or the like on the rear surface is high, and the number of the components and the price can be reduced because the upper and lower conductive layers 3 and 4 are unitarily formed on the upper and lower phase difference plates 11 and 12, respectively. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a touch panel used for operating various electronic devices.

  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 2000-10732 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. When the surroundings are bright, such as outdoors or under fluorescent lights, external light such as sunlight or light is reflected on the top and bottom surfaces of the screen, making it difficult to see the display on the back of the touch panel. .

  In addition, in order to improve the visibility due to the reflection of the external light, a polarizing plate and a plurality of retardation plates are proposed to be superimposed on the upper and lower surfaces of the touch panel. However, there was a problem that the touch panel becomes expensive.

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

  In order to achieve the above object, the present invention provides a touch panel in which a lower conductive layer on a lower retardation plate upper surface is opposed to an upper conductive layer on a lower retardation plate having a polarizing plate on the upper surface with a predetermined gap therebetween. The polarizing plate, the upper retardation plate, and the lower retardation plate prevent reflection of external light, providing good visibility of the liquid crystal display element on the back surface, and the upper and lower conductive layers on the upper and lower retardation plates. Since they are integrally formed, the number of components is small, and an inexpensive touch panel can be obtained.

  As described above, according to the present invention, it is possible to obtain an advantageous effect that it is possible to realize an inexpensive touch panel with good visibility.

  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 11 denotes a flexible film having a quarter wavelength obtained by stretching a film of polycarbonate or cycloolefin polymer to give birefringence. The upper retardation plate 12 is also a lower retardation plate. The upper retardation plate 11 has a light-transmissive upper conductive layer 3 such as indium tin oxide or tin oxide on the lower surface thereof, and the lower retardation plate 12 has a lower surface. The 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 nonwoven fabric or a polyester film, and the outer circumferences of the upper retardation plate 11 and the lower retardation plate 12 are bonded to each other by an adhesive layer (not shown) formed on the upper and lower surfaces of the spacer 5. The upper conductive layer 3 and the lower conductive layer 4 are opposed to each other with a predetermined gap.

  Furthermore, 13 is a flexible polarizing plate in which triacetyl cellulose or the like is laminated on the upper and lower surfaces of polyvinyl alcohol that has been adsorbed with iodine or a dye and stretched / oriented. This polarizing plate 13 is an adhesive such as acrylic (see FIG. The touch panel is configured by being attached and pasted on the upper surface of the upper retardation plate 11.

  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 polarizing plate 13 is pressed with a finger or a pen while visually recognizing the display of the liquid crystal display element on the back surface of the touch panel, the polarizing plate 13 and the upper retardation plate 11 are bent and the upper conductive portion is pressed. Layer 3 contacts lower conductive 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. Has been.

  At this time, external light such as sunlight and lamps from above first passes through the polarizing plate 13, so that, for example, the polarizing plate 13 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 upper retardation plate 11 from the polarizing plate 13.

  Next, the light passes through the upper retardation plate 11 of 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 upper retardation plate 11 again, so that the wavelength is further shifted by λ / 4 and enters the polarizing plate 13 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 13.

  That is, external light that has entered the touch panel from above is reflected upward by the lower conductive layer 4, but this reflected light is blocked by the polarizing plate 13 and is not emitted from the upper surface of the polarizing plate 13 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 surface of the touch panel is linearly polarized in the Y direction, it first passes through the lower phase difference plate 12 to shift the wavelength by λ / 4, and then the upper phase difference plate. By passing through 11, the wavelength further shifts by λ / 4, becomes linearly polarized light in the X direction, enters the polarizing plate 13, and exits from the upper surface of the polarizing plate 13 which is the operation surface.

  That is, the lighting light from the liquid crystal display element or the like passes through the lower retardation plate 12 and the upper retardation plate 11 to become linearly polarized light in the X direction, and is emitted from the upper surface of the polarizing plate 13 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.

  Further, since the upper conductive layer 3 is integrally formed on the lower surface of the upper retardation plate 11 and the lower conductive layer 4 is integrally formed on the upper surface of the lower retardation plate 12, the upper conductive layer 3 is composed of only indispensable components for the touch panel. The touch panel can be made inexpensive.

  As described above, according to the present embodiment, the lower conductive layer 4 on the lower retardation plate 12 is opposed to the upper conductive layer 3 on the lower surface of the upper retardation plate 11 having the polarizing plate 13 mounted on the upper surface with a predetermined gap therebetween. By configuring the touch panel as described above, reflection of external light is prevented by the polarizing plate 13, the upper retardation plate 11, and the lower retardation plate 12, and good visibility of the liquid crystal display element on the back surface and the like is obtained. Since the layers 3 and 4 are integrally formed on the upper and lower retardation plates 11 and 12, respectively, the number of components is small and an inexpensive touch panel can be obtained.

  The touch panel according to the present invention has an advantageous effect that it has good visibility and can provide an inexpensive one, and is useful for operation of 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

3 Upper conductive layer 4 Lower conductive layer 5 Spacer 11 Upper retardation plate 12 Lower retardation plate 13 Polarizing plate

Claims (1)

An upper retardation plate having an upper conductive layer formed on the lower surface, a polarizing plate mounted on the upper surface of the upper retardation plate, and a lower conductive layer formed on the upper surface and facing the upper conductive layer with a predetermined gap therebetween A touch panel consisting of a phase difference plate.

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