JP2010079781A - Resistive film type touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistive film type touch panel which prevents deterioration of a movable electrode and maintains linearity even if an input-disabled area is touched. <P>SOLUTION: The resistive film type touch panel 10 is configured by bonding a surface film 13 having a movable electrode 14 and a fixed electrode substrate 17 having a fixed electrode 18 with an insulating adhesive layer 16. The movable electrode 14 is separated from the insulating adhesive layer 16 across a wiring electrode 15, and a light shielding section 21 is used to protect the input-disabled part, thereby improving durability. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a touch panel, particularly a resistive touch panel.

  Conventionally, the resistive touch panel has been widely used in ATM terminals, ticket vending machines, FA control devices, and the like. In FIG. 7, the cross section of the periphery part of the conventional resistive film type touch panel 40 is shown typically. In the conventional resistive film type touch panel 40, a movable electrode 42 made of a transparent electrode material is formed on the inner surface of a surface film 41, and a wiring electrode 43 is formed at the end of the movable electrode 42. Input is performed from the outer surface of the surface film 41. As the movable electrode 42, a transparent ITO (Indium Tin Oxide) thin film is usually used. As the wiring electrode 43, a thin film formed from silver ink or carbon ink is usually used. The wiring electrode 43 is opaque. The surface film 41 and the fixed electrode substrate 45 are coupled and fixed via the frame-shaped insulating adhesive layer 44. A fixed electrode 46 is formed on the surface of the fixed electrode substrate 45. As the fixed electrode 46, an ITO thin film is usually used. The fixed electrode 46 and the fixed electrode substrate 45 are transparent. The surface film 41 is deformed by being pressed (touched) with a finger or a pen from the input surface side (outside), and the movable electrode 42 is recessed to come into contact with the fixed electrode 46 to detect a coordinate signal of the touch position. Is done. The insulating adhesive layer 44 also serves as a spacer for preventing the movable electrode 42 from contacting the fixed electrode 46 when the surface film 41 is not touched. For the reason described later, the end of the input area is covered with a bezel 47 (a plastic or metal window frame-shaped housing).

  In FIG. 8, the typical top view of the conventional resistive film type touch panel 40 is shown. Wiring electrodes 43 are arranged on two opposite sides of the rectangular movable electrode 42. An inner end 44 a of the frame-like insulating adhesive layer 44 is on the inner side (center side in the drawing) than the wiring electrode 43. The input area 48 is a rectangular part surrounded by a two-dot chain line. The input impossibility region is a portion outside the input region 48 and inside the end 44 a inside the insulating adhesive layer 44.

  FIG. 9 schematically shows a cross section of the peripheral portion of the conventional resistive film type touch panel 40 when the bezel 47 is not provided. FIG. 9 shows a state where the input impossible area is touched. Since the movable electrode 42 in the vicinity of the insulating adhesive layer 44 is fixed to the insulating adhesive layer 44 in the vicinity of a portion 49 surrounded by a broken line, the bending direction when touched is abrupt, and the elongation rate is higher than the central portion. Is also big. As a result, a crack (not shown) may occur in the portion 49 surrounded by the broken line of the movable electrode 42. When a crack occurs in the movable electrode 42, the resistance value of the movable electrode 42 changes. Since the resistive touch panel detects the touch position based on the resistance value, if the resistance value changes, the coordinates of the touch position cannot be accurately detected. This is also said to have reduced linearity. When the accuracy or linearity of the coordinates of the touch position is lowered, the resistive touch panel cannot be used.

  As described above, when the resistance film type touch panel is touched, a portion where the elongation rate of the movable electrode is large and the resistance value of the movable electrode is likely to change is the non-inputable region. As shown in FIG. 8, the input impossible area is usually outside the two sides at both ends of the input area 48 and inside the end 44 a inside the insulating adhesive layer 44. The width of the non-inputable region is mainly determined by the thickness of the insulating adhesive layer 44, and is usually about 20 to 50 times the thickness of the insulating adhesive layer 44. Conventionally, as shown in FIG. 7, the non-inputable area is covered with a bezel 47 so that the touch cannot be physically performed, thereby preventing the detection accuracy of the resistive touch panel from being lowered (for example, Patent Document 1).

  Recently, a resistive touch panel has been mounted as an input device on liquid crystal display screens of mobile phones, notebook computers, digital cameras, digital videos, PDAs and the like. In the case of such a portable electronic device, a flat structure in which there is no difference in height between the input region of the resistive touch panel and the connecting portion of the device housing is preferred. For example, in the case of a structure in which an image display unit on which a resistive touch panel is mounted and a main unit on which a key switch or the like is mounted is folded in two, if the entire image display unit is flat, Since the thickness of is reduced, it is convenient. In addition, there is a mobile phone in which the entire surface of the main body is a resistive touch panel. In this case, a structure having a flat surface with no difference in height is preferred.

  FIG. 10 is a schematic cross-sectional view of a peripheral portion of a conventional resistive touch panel 50 having a flat structure in which there is no difference in height between the input area of the resistive touch panel 50 and the connecting portion 51a of the device casing 51. Shown in A movable electrode 53 made of a transparent electrode material is formed on one surface of the surface film 52, and a wiring electrode 54 is formed at the end of the movable electrode 53. The surface film 52 and the fixed electrode substrate 56 are bonded and fixed via the frame-shaped insulating adhesive layer 55. A fixed electrode 57 is formed on the surface of the fixed electrode substrate 56. The movable electrode 53 and the fixed electrode 57 are usually made of an ITO thin film. The wiring electrode 54 is usually formed from silver ink or carbon ink. The surface film 52 is deformed by being pressed (touched) with a finger or a pen from the surface side of the cover film 58, the movable electrode 53 is recessed and comes into contact with the fixed electrode 57, and a coordinate signal of the touch position is detected Is done. The insulating adhesive layer 55 also serves as a spacer for preventing the movable electrode 53 from contacting the fixed electrode 57 when the surface film 52 is not touched. For example, a liquid crystal display element 59 is provided below the transparent fixed electrode substrate 56.

  In such a resistive touch panel 50 having a flat connection portion 51a with the device casing 51, the non-inputable area cannot be physically covered with a plastic or metal bezel. For this reason, there is a risk of touching the non-inputable area without knowing it.

FIG. 11 is a schematic cross-sectional view of a conventional resistive touch panel 50 having a flat connection part 51a with the device casing 51 when an input impossible area is touched. Since the end portion of the movable electrode 53 in the vicinity of the insulating adhesive layer 55 surrounded by the broken line 60 is fixed to the insulating adhesive layer 55, the bending direction when touched is abrupt and the elongation rate is higher than that of the central portion. large. Therefore, a crack (not shown) may occur in the portion surrounded by the broken line 60 of the movable electrode 53. If a crack occurs, the resistance value may fluctuate, and the coordinates of the touch position may not be detected accurately. As described above, the resistive touch panel 50 in which the connecting portion 51a to the device housing 51 is flat cannot cover the non-inputable area with the bezel. Therefore, there is a high possibility that the accuracy of the resistive touch panel 50 is deteriorated, and it has been forced to use.
JP 2005-317409 A

  Recently, the resistive touch panel with a flat connection to the device casing, which is widely used in portable electronic devices, cannot cover the non-inputable area with a plastic or metal bezel. . For this reason, there is a risk of touching without knowing the non-inputable area and degrading the movable electrode.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have separated the movable electrode and the insulating adhesive layer by the wiring electrode. It was found that a resistive touch panel that does not change linearity can be realized.

The gist of the present invention is as follows.
(1) The resistive touch panel of the present invention is a resistive touch panel in which a surface film having a movable electrode and a fixed electrode substrate having a fixed electrode are bonded and fixed with an insulating adhesive layer. The layer is separated by a wiring electrode.
(2) The resistive touch panel of the present invention is characterized in that there is no overlapping portion between the movable electrode and the insulating adhesive layer when viewed from a direction perpendicular to the input surface of the resistive touch panel.
(3) In the resistive film type touch panel of the present invention, the wiring electrode extends in the center direction of the input surface from the inner end of the insulating adhesive layer, and the length (cover length) of the extending portion is The thickness of the insulating adhesive layer is 30 to 40 times.
(4) The resistive touch panel of the present invention is characterized in that the wiring electrode is made of a conductive material obtained by adding a flexible resin to silver particles, carbon particles, or a mixture thereof.
(5) The resistive touch panel of the present invention is characterized by having a light-shielding portion that hides the wiring electrode when viewed from a direction perpendicular to the input surface of the resistive touch panel.

  According to the present invention, even when the non-inputable area is touched on the resistive touch panel having a flat structure connected to the device housing, the non-inputable area cannot be covered with a plastic or metal bezel. There is no possibility of deteriorating the movable electrode and changing the linearity.

  FIG. 1 schematically shows a cross-section of the peripheral portion when the first embodiment of the resistive touch panel 10 of the present invention is mounted on the equipment casing 11. The resistive touch panel 10 of the present invention is suitable for realizing a flat structure in which there is no difference in height in the connecting portion 12 between the resistive touch panel 10 and the device housing 11. In the resistive touch panel 10 of the present invention, the movable electrode 14 made of a transparent electrode material is formed on the inner surface of the surface film 13, and the wiring electrode 15 is formed at the end of the movable electrode 14. The periphery of the surface film 13 and the periphery of the fixed electrode substrate 17 are coupled and fixed via the frame-shaped insulating adhesive layer 16. A fixed electrode 18 is formed on the surface of the fixed electrode substrate 17. The movable electrode 14 and the fixed electrode 18 are usually made of an ITO thin film. The wiring electrode 15 is usually made of a conductive material containing silver particles or carbon particles. The surface film 13 is deformed by being pressed (touched) with a finger or a pen from the top of the cover film 19, the movable electrode 14 is recessed and comes into contact with the fixed electrode 18, and a coordinate signal of the touch position is detected. The The insulating adhesive layer 16 also serves as a spacer for preventing the movable electrode 14 from coming into contact with the fixed electrode 18 when the surface film 13 is not touched. For example, a liquid crystal display element 20 is provided below the transparent fixed electrode substrate 17. Unlike the conventional product, the wiring electrode 15 is provided from the insulating adhesive layer 16 to the inside of the input region (right side in the figure). Thereby, the movable electrode 14 and the insulating adhesive layer 16 are separated by the wiring electrode 15, and there is no place where the movable electrode 14 and the insulating adhesive layer 16 are in direct contact. Further, the light shielding portion 21 is provided on the inner surface of the cover film 19 up to substantially the same position as the wiring electrode 15. The light shielding portion 21 prevents the wiring electrode 15 from being seen from the surface side (upper side in the figure) of the input region.

  In FIG. 2, the typical top view of one Example of the resistive film type touch panel 10 of this invention is shown. Wiring electrodes 15 are arranged on two opposite sides of the rectangular movable electrode 14. Unlike the conventional product, the inner end 15a of the wiring electrode 15 is further on the inner side (from the center of the drawing) of the inner end 16a of the frame-like insulating adhesive layer 16. The input area 22 is a rectangular portion surrounded by a two-dot chain line. The length of the portion of the wiring electrode 15 extending inward from the inner end 16a of the insulating adhesive layer 16 is referred to as a cover length L.

  The input region 22 is inside a rectangle surrounded by a one-dot chain line, and two sides of the input region 22 substantially coincide with the inner end 15 a of the wiring electrode 15. The non-inputable area is between the inner end 15a of the wiring electrode 15 and the inner end 16a of the insulating adhesive layer 16, and substantially coincides with the cover length L. The width of the non-inputable area and the cover length L are mainly determined by the thickness of the insulating adhesive layer 16 and are usually about 20 to 50 times the thickness of the insulating adhesive layer 16.

  FIG. 3 schematically shows a cross section of the resistive touch panel 10 according to the first embodiment of the present invention in a state where the input impossible area is touched. Unlike the conventional one, the movable electrode 14 in the vicinity of the insulating adhesive layer 16 is not directly fixed to the insulating adhesive layer 16, and there is a wiring electrode 15 between the insulating adhesive layer 16 and the movable electrode 14. . For this reason, even if the non-inputable area is touched, the flexible wiring electrode 15 serves as a cushioning material, so the bending of the movable electrode 14 is not as steep as in the prior art and the elongation rate is small. Accordingly, there is less risk of cracks occurring in the movable electrode 14 than in the conventional product. Since the wiring electrode 15 is thicker than the movable electrode 14 and rich in flexibility, cracks are much less likely to occur than the movable electrode 14. Further, since the resistance value of the wiring electrode 15 is orders of magnitude lower than that of the movable electrode 14, even if a crack occurs in the movable electrode 14 and the resistance value changes, the resistance of the (wiring electrode 15 + movable electrode 14) The value does not change substantially. As a result, in the resistive touch panel 10 of the present invention, even if an input impossible area is touched, there is very little possibility that the accuracy of the coordinates of the touch position and the linearity will deteriorate.

  In FIG. 4, the cross section of the peripheral part of the 2nd Example of the resistive film type touch panel 30 of this invention is shown typically. In the first embodiment shown in FIG. 1, the movable electrode 14 overlaps the insulating adhesive layer 16, but in the embodiment shown in FIG. 4, the movable electrode 31 does not overlap the insulating adhesive layer 32. . In other words, there is no overlap between the movable electrode 14 and the insulating adhesive layer 16 when viewed from the direction perpendicular to the input surface of the resistive touch panel 30.

  FIG. 5 schematically shows a cross section of the second embodiment of the resistive touch panel 30 according to the present invention in a state where the input impossible area is touched. Since the end of the movable electrode 31 is in contact with the flexible wiring electrode 33, the bending of the movable electrode 31 is more gradual than in the first embodiment, and a crack occurs in the movable electrode 31. There is less fear. The fact that there is very little risk of cracks occurring in the wiring electrode 33, and that the resistance value of (wiring electrode 33 + movable electrode 31) does not substantially change even if cracks occur in the wiring electrode 33. This is the same as in the first embodiment.

  The resistance film type touch panel of the first embodiment shown in FIG. 2 is a silver film in which the insulating adhesive layer 16 has a thickness of 0.075 mm, and the wiring electrode 15 has silver particles added with a highly flexible polyester resin. A prototype was made using ink. At this time, three types of resistive film type touch panels having cover lengths L of the wiring electrodes 15 of 0 mm, 1.5 mm, and 2.5 mm were produced. The cover length L = 1.5 mm of the wiring electrode 15 corresponds to 20 times the thickness of the insulating adhesive layer 16, and 2.5 mm corresponds to 33 times. With respect to each resistive film type touch panel, a test of repeatedly touching a position of 2 mm from the inner end 16a of the insulating adhesive layer 16 to the inner side (from the center) was performed, and a change in linearity was examined.

  FIG. 6 is a graph showing a change in linearity in the repeated touch test. When the cover length L of the wiring electrode 15 was 0 mm, the number of touches was 100 and the linearity changed by 5%. When the cover length L of the wiring electrode 15 was 1.5 mm, the number of touches was 300, and the linearity changed by 5%. These are not practical enough. In contrast, when the cover length L of the wiring electrode 15 was 2.5 mm, the linearity did not change even when the number of touches was 500. Further, although not shown in the graph, the test was continued up to 100,000 touches, but the linearity did not change. Therefore, if the cover length L of the wiring electrode 15 is 30 times or more the thickness of the insulating adhesive layer 16, the linearity is hardly changed, and the practicality is sufficient.

  The longer the cover length L of the wiring electrode 15 is, the smaller the linearity change in the repeated touch test is expected. That is, the resistance film type touch panel is less deteriorated. However, the longer the cover length L of the wiring electrode 15, the narrower the input area. Therefore, it is not preferable that the cover length L of the wiring electrode 15 is longer than necessary. For this reason, the cover length L of the wiring electrode 15 is suitably 40 times or less the thickness of the insulating adhesive layer. Accordingly, the cover length L of the wiring electrode is suitably 30 to 40 times the thickness of the insulating adhesive layer.

  In the above embodiment, silver particles are used as the wiring electrode. However, carbon particles or a mixture of silver particles and carbon particles may be used.

Sectional view of the periphery of the first embodiment of the resistive touch panel of the present invention The top view of the 1st Example of the resistive film type touch panel of this invention Sectional drawing of the state where the input impossible area was touched in the first embodiment of the resistive touch panel of the present invention Sectional view of the periphery of the second embodiment of the resistive touch panel of the present invention Sectional drawing of the state in which the input impossible area was touched in 2nd Example of the resistive touch panel of this invention Graph showing change in linearity in repeated touch test Cross-sectional view of the periphery of a conventional resistive touch panel Plan view of a conventional resistive touch panel Cross-sectional view of the periphery of a conventional resistive touch panel without a bezel Cross-sectional view of the periphery of a conventional resistive touch panel with a flat structure Sectional view when a non-input area is touched on a conventional resistive touch panel with a flat structure

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Resistance film type touch panel 11 Equipment housing | casing 12 Portion 13 Surface film 14 Movable electrode 15 Wiring electrode 15a End 16 inside a wiring electrode Insulating adhesive layer 16a End 17 inside an insulating adhesive layer Fixed electrode substrate 18 Fixed electrode 19 Cover film Liquid crystal display element 21 Light shielding part 22 Input region 30 Resistive touch panel 31 Movable electrode 32 Insulating adhesive layer 33 Wiring electrode 40 Resistive touch panel 41 Surface film 42 Movable electrode 43 Wiring electrode 44 Insulating adhesive layer 44a Inner end of insulating adhesive layer 45 Fixed electrode substrate 46 Fixed electrode 47 Bezel 48 Input region 49 Part 50 enclosed by broken line Resistance film type touch panel 51 Device casing 51a Connecting part 52 Surface film 53 Movable electrode 54 Wiring electrode 55 Insulating adhesive layer 56 Fixed electrode substrate 57 Fixed electrode 58 Cover film 59 Liquid crystal display element 6 The portion surrounded by a broken line

Claims (5)

  A resistive touch panel in which a surface film having a movable electrode and a fixed electrode substrate having a fixed electrode are bonded and fixed with an insulating adhesive layer, wherein the movable electrode and the insulating adhesive layer are separated by a wiring electrode. A resistive touch panel characterized by that.   The resistive touch panel according to claim 1, wherein when viewed from a direction perpendicular to the input surface of the resistive touch panel, there is no overlapping portion between the movable electrode and the insulating adhesive layer.   The wiring electrode extends in the center direction of the input surface from the inner end of the insulating adhesive layer, and the length of the extending portion is 30 to 40 times the thickness of the insulating adhesive layer. The resistive touch panel according to claim 1, wherein the resistive touch panel is provided.   4. The resistive film type according to claim 1, wherein the wiring electrode is made of a conductive material obtained by adding a flexible resin to silver particles, carbon particles, or a mixture thereof. 5. Touch panel.   5. The resistive film type touch panel according to claim 1, further comprising a light shielding portion that hides the wiring electrode when viewed from a direction perpendicular to an input surface of the resistive film type touch panel.

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