Touch panel

A touch panel includes multiple first electrodes, multiple first wiring lines, multiple second electrodes, multiple second wiring lines, a switch electrode, a third wiring line, and a shield section. The first electrodes are disposed parallel to each other in the first direction. The second electrodes intersect with the first electrodes, and are disposed parallel to each other in the second direction. The shield section is insulated from the second wiring lines and the third wiring lines, and is disposed to cover the second wiring lines and the third wiring lines.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application of the PCT International Application No. PCT/JP2014/001813 filed on Mar. 28, 2014, which claims the benefit of foreign priority of Japanese patent application 2013-091010 filed on Apr. 24, 2013, the contents all of which are incorporated herein by reference.

TECHNICAL FIELD

The technical field relates to capacitive touch panels used mainly for operating various input devices.

BACKGROUND ART

In recent years, input devices with various display patterns achieved by mounting a light-transmissive touch panel on a display face of display device, such as liquid crystal display, have been employed typically in mobile phones and car navigation systems.

In these input devices, a menu is displayed on a display device, and the user operates the touch panel to execute predetermined controls.

FIG. 6is a top view of conventional input device10.FIG. 7is a schematic sectional view of conventional input device10.FIGS. 6 and 7illustrate input device10employing resistive film touch panel1.

To allow easy-understanding of the structure, dimensions in the thickness direction are magnified in the drawings. In resistive film touch panel1, transparent surface electrode18A is formed on substrate16. Transparent surface electrode18B is formed on substrate17. Substrate16and substrate17are bonded with adhesive20such that surface electrode18A and surface electrode18B face each other with a predetermined space in between. Surface electrode18A touches surface electrode18B when the user presses substrate16with a finger, and a change in voltage is detected at a portion pressed.

Input device10includes touch panel1and display device2. Touch panel1is disposed on the top face of display device2. An area of touch panel1is larger than that of display device2, and thus touch panel1has independent touch panel area1A that is not overlaid on display device2.

Display device2displays menus3and4. Menu4can be operated by pressing control part5of touch panel1. Control part5corresponds to the top face of menu4and detection area6in independent touch panel area1A.

Since control part5includes detection area6in independent touch panel area1A, control part5can be made broader than menu4even if an area for displaying menu4is small. Accordingly, reliable operation can be achieved.

The prior art document regarding this application is known, for example, PTL1.

CITATION LIST

Patent Literature

SUMMARY OF THE INVENTION

A touch panel includes multiple first electrodes, multiple first wiring lines, multiple second electrodes, multiple second wiring lines, a switch electrode, a third wiring line, and a shield section. The first electrodes are disposed parallel to each other in the first direction. The first wiring lines are connected to the respective first electrodes. The second electrodes are insulated from the first electrodes, intersect with the first electrodes, and are disposed parallel to each other in the second direction. The second wiring lines are connected to the respective second electrodes. The switch electrode is insulated from the first electrodes and the second electrodes. The third wiring line is connected to the switch electrode. The shield section is insulated from the second wiring lines and the third wiring line, and disposed to cover the second wiring lines and the third wiring line.

DESCRIPTION OF EMBODIMENTS

Before describing an exemplary embodiment, the problem of the prior art is described. When resistive film touch panel1, as shown inFIGS. 6 and 7, is used, detection accuracy reduces as the screen becomes larger in size. In addition, further higher durability and impact resistance are required. Therefore, a capacitive touch panel that has high durability, impact resistance, and detection accuracy has been increasingly used in recent years.

In the capacitive touch panel, an electrode is formed on a substrate, and then a cover is provided on it. Electrostatic capacitance changes as the user puts his/her finger closer to the cover surface, and thus a finger position is detected.

When the capacitive touch panel is used, it is better to display menu4using individual switch electrodes (not illustrated) than to provide menu4in display part1B, as inFIG. 6. This is more preferable because display part1B can be fully used and reliable menu operation can also be achieved. However, if menu4is displayed using individual switch electrodes, electromagnetic waves entering from outside may generate noise and cause faulty operation.

The exemplary embodiment that solves the above problem of the prior art is described below with reference to drawings.

To make the structure easy to understand, dimensions are partially magnified in the drawings.

FIG. 1is an exploded perspective view of a touch panel in the exemplary embodiment.FIG. 2is a sectional view of the touch panel in the exemplary embodiment.

Touch panel100includes multiple first electrodes31, multiple first wiring lines32, multiple second electrodes41, multiple second wiring lines42, switch electrode43, third wiring line44, and shield sections33and34. First electrodes31are disposed parallel to each other in first direction D1. First wiring lines32are connected to respective first electrodes31. Second electrodes41are insulated from first electrodes31, intersect with first electrodes31, and are disposed parallel to each other in second direction D2. Second wiring lines42are connected to respective second electrodes41. Switch electrode43is insulated from first electrodes31and second electrodes41. Third wiring line44is connected to switch electrode43. Shield sections33and34are insulated from second wiring lines42and third wiring line44, and disposed to cover second wiring lines42and third wiring line44.

Touch panel100in the exemplary embodiment is detailed below. Touch panel100includes cover layer21, first substrate layer22, and second substrate layer23.

Substantially-rectangular cover layer21is, for example, formed by providing a hard coat layer on the top face of a resin film. Alternatively, cover layer21may be formed of glass.

First substrate layer22includes first substrate35, and multiple first electrodes31, multiple first wiring lines32, and shield sections33and34formed on first substrate35. In other words, first electrodes31, first wiring lines32, and shield sections33and34are formed on the same plane, and they are supported by first substrate35. First electrodes31are formed in first direction D1. Each end of first wiring lines32is connected to each of first electrodes31. Shield sections33and34are disposed to the left and right of first substrate35with first electrodes31in between. Here, first direction D1is the short-side direction of first substrate layer22. The left and right direction is a direction perpendicular to the extending direction of first electrodes31.

First substrate35is substantially rectangular, and is formed, for example, of a light-transmissive insulating resin film. Alternatively, first substrate35may be formed of glass.

First electrodes31are aligned at a predetermined interval. In addition, first electrodes31have belt shapes with substantially the same width. First electrodes31are preferably formed of indium tin oxide or tin oxide, or the like.

First wiring lines32are extended from one ends of first electrodes31, respectively. However, each of first wiring lines32may also be extended from both ends of each of first electrodes31. First wiring lines32are preferably formed of metal, such as silver and copper.

Shield section33is disposed to the left of first electrodes31. Shield section34is disposed to the right of first electrodes31. Multiple holes33A are created in shield section33. Multiple holes34A are created in shield section34. Switch electrode43is exposed from each of holes33A and34A so that switch electrode43can be operated. Shield sections33and34are preferably formed of metal, such as silver and copper.

Second substrate layer23includes second substrate45, and multiple second electrodes41, multiple second wiring lines42, multiple switch electrodes43, and multiple third wiring lines44formed on second substrate45. In other words, second electrodes41, second wiring lines42, switch electrodes43, and third wiring lines44are formed on the same plane, and they are supported by second substrate45. Second electrodes41are formed parallel to each other in second direction D2. Ends of second wiring lines43are connected to second electrodes41, respectively. Third wiring lines44are connected to switch electrodes43. Here, second direction D2is the long-side direction of second substrate layer23.

In the exemplary embodiment, first direction D1is the short-side direction of first substrate layer22, and second direction D2is the long-side direction of second substrate layer23. However, first direction D1and second direction D2are not limited to the above directions, as long as first direction D1and second direction D2are not parallel and have a predetermined angle to each other. Preferably, however, first direction D1is perpendicular to second direction D2.

Here, second substrate45is substantially rectangular, and is formed, for example, of a light-transmissive insulating resin film. Alternatively, second substrate45may be formed of glass.

Second electrodes41are aligned at a predetermined interval. In addition, second electrodes41have belt shapes with substantially the same width. Second electrodes41are preferably formed of indium tin oxide or tin oxide, or the like.

Each of second wiring lines42is extended from both ends of each of second electrodes41. However, second wiring lines42may be extended from one ends of second electrodes41. Second wiring lines42are preferably formed of silver or copper, or the like.

Switch electrodes43are configured by combining comb-like electrodes43A and43B. Electrodes43A and43B are formed of a light-transmissive conductive material, such as indium tin oxide and tin oxide, or metal, such as silver and copper.

As a material for switch electrode43, a light-transmissive conductive material is preferably used. By using the light-transmissive conductive material, switch electrode43can be lighted from beneath or an icon can be disposed beneath. This enables to change the display of switch electrode43.

Third wiring lines44are extended from electrodes43A and43B. Third wiring lines44are preferably formed of metal, such as silver and copper.

As described above, conductive metal is preferably used as materials for first wiring lines3, second wiring lines42, and third wiring lines44. Conductive metal has resistance smaller than that of light-transmissive conductive material, and thus loss at transmitting signals reduces.

First substrate layer22is fixed on the top face of second substrate layer23, typically by acrylic adhesive (not illustrated). Then, cover layer21is fixed on the top face of first substrate layer22, typically by acrylic adhesive (not illustrated).

In the above structure, shield section33or shield section34covers an upside of second wiring lines42and third wiring lines44. Therefore, shield section33and shield section34can attenuate electromagnetic waves reaching touch panel100from outside. Noise on second wiring lines42and third wiring lines44is thus suppressed. Comparing the average lengths, second wiring lines42are longer than first wiring lines32. In addition, third wiring lines44are longer than first wiring lines32. Therefore, noise enters more easily to second wiring lines42than to first wiring lines32. Noise also enters more easily to third wiring lines44than to first wiring lines32. Accordingly, noise can be effectively suppressed by forming shield section33or shield section34over second wiring lines42and third wiring lines44.

FIG. 3is a perspective view of touch panel100in the exemplary embodiment.

Operation area60is an area where first electrodes31and second electrodes41are disposed. Here, second electrodes41are sending electrodes, and first electrodes31are receiving electrodes. For example, second electrodes41achieve transmission by switching one by one from the back to front. While second electrodes41are transmitting, first electrodes31receiving it are switched one by one, for example, from the left end to the right end. Then, a change in electrostatic capacitance in one of first electrodes31is detected based on electrostatic capacitance detected at first electrodes31. This allows to determine a detected object position, such as a finger, in second direction D2. Also at this point, a detected object position, such as a finger, in first direction D1is determined by determining which of second electrodes41is making transmission. As a result, the detected object position is identified. Here, the back side refers to a part away from first wiring lines32, and the front side refers to a part close to first wiring lines32.

First wiring lines32, shield sections33and34, second wiring lines42, switch electrodes43, and third wiring lines44are disposed on both sides (outside) of operation area60. In other words, third wiring lines44are disposed in first direction D1on both sides (outside) of second electrodes41. Switch electrodes43are disposed on both sides (outside) of second electrodes41. Shield sections33and34are disposed in first direction D1on both sides (outside) of first electrodes31.

Electrodes43A and43B configuring switch electrode43operate as electrodes for sending or receiving the electric field. Approach or contact of an object, such as a finger, is determined based on a change in electrostatic capacitance detected via electrodes43A and43B. In other words, operation area60is employed as a projected capacitive form, and switch electrode43is employed as a surface capacitive form.

FIG. 4is a sectional view of input device110employing touch panel100in the exemplary embodiment. Input device110includes touch panel100, casing101, and display device102.

Casing101has square hole101A at a position corresponding to operation area60. Casing101also has square hole101B at a position corresponding to switch electrodes43to the left, and square hole101C at a position corresponding to switch electrodes43to the right.

Display device102includes a display element, such as liquid crystal display or organic electroluminescence display, and is disposed on the bottom face of touch panel100. The user can operate touch panel100typically with a finger while looking at an image on display device102through touch panel100.

First electrodes31are connected to an electronic circuit (not illustrated) of input device110via first wiring lines32, second electrodes41via second wiring lines42, and switch electrodes43via third wiring lines44. Display device102is connected to the electronic circuit (not illustrated) of input device110typically via a connector and lead wire (not illustrated).

When the user moves an object, such as a finger, close to touch panel100, electrostatic capacitance between first electrode31and second electrode41changes. Alternatively, electrostatic capacitance of switch electrode43changes. Then, the electronic circuit detects this change. In this way, approach or contact of object, such as a finger, is determined on touch panel100. Then, diversifying functions of input device110are switched depending on the approach or contact position of the object.

For example, if input device110is used as a car navigation system, a map is displayed on a position corresponding to operation area60of display device102. In addition, menus are displayed on a position corresponding to switch electrodes43of display device102. For example, the menus are a selection menu for displaying a wide/detailed map, a switching menu for displaying audio, and a selection menu for displaying audio volume.

In the state a map is displayed, a map at a contact position changes to a wide display or detail display when the user touches and pinches operation area60with two fingers. By flicking, the map quickly scrolls in a predetermined direction. The pinching operation refers to the operation of making two fingers touching the top face of touch panel100come close or separate. The flicking operation refers to the operation of quickly sliding the finger touching the top face of touch panel100.

If the user touches the top face of touch panel100corresponding to switch electrode43when ‘audio’ is displayed on the menu, a display on display device102switches to audio.

FIG. 5Ais a top view of switch electrode43of touch panel100in the exemplary embodiment. The exemplary embodiment uses comb-like electrodes43A and43B as switch electrode. However, a switch electrode with any shape is applicable as long as a change in electrostatic capacitance is detectable.FIGS. 5B to 5Dare top views of other switch electrodes of touch panel100in the exemplary embodiment. As shown in switch electrode121inFIG. 5B, electrodes121A and121B may be spiral. In addition, as shown in switching electrode122inFIG. 5Cand switch electrode123inFIG. 5D, the switch electrode may be configured with a single electrode.

In the exemplary embodiment, shield sections33and34are formed on first substrate35where first electrodes31and first wiring lines32are formed. However, shield sections33and34may be formed on a substrate other than first substrate35. Moreover, shield sections33and34may be formed on cover layer21. However, shield sections33and34can be formed together with first wiring lines32if they are formed on first substrate35in the case shield sections33and34are formed of conductive metal. In the case shield sections33and34are formed of a light-transmissive conductive material, they can be formed together with first electrodes31, typically by printing. This facilitates fabrication. Accordingly, shield sections33and34are preferably formed simultaneously with first electrodes31or first wiring lines32. In other words, shield sections33and34are preferably formed on first substrate35.

Furthermore, switch electrode43and third wiring lines44are formed on second substrate45where second electrodes41are formed in the exemplary embodiment. However, switch electrodes43and third wiring lines44may be formed on a substrate other than second substrate45. However, if switch electrodes43are formed of a light-transmissive conductive material, such as indium tin oxide and tin oxide, they can be formed together with second electrodes41. If switch electrodes43are formed of conductive metal, such as silver and copper, they can be formed together with second wiring lines42or third wiring lines44. Accordingly, switch electrodes43and third wiring lines44are preferably formed on second substrate45.

In the exemplary embodiment, second electrodes41are sending electrodes and first electrodes31are receiving electrodes. However, second electrodes41may be receiving electrodes and first electrodes31may be sending electrodes.

First electrodes31and second electrodes41may also be formed in a strip of multiple diamond-shaped electrodes. In other words, these electrodes may be configured with a string of diamond-like electrodes.

As described above, touch panel100in the exemplary embodiment includes multiple first electrodes31disposed parallel to each other, first wiring lines connected to first electrodes31, and shield sections33and34insulated from first electrodes31. Touch panel100further includes multiple second electrodes41insulated from first electrodes31and disposed parallel to each other, second wiring lines42connected to second electrodes41, switch electrodes43insulated from first electrodes31and second electrodes41, and third wiring lines44connected to switch electrodes43. An approach or contact position of an object is detected by a change in electrostatic capacitance between first electrode31and second electrode41. An approach or contact position of the object is also detected by a change in electrostatic capacitance of switch electrode43. Shield sections33and34are disposed to cover second wiring lines42and third wiring lines44in the top view. Shield sections33and34suppress entry of electromagnetic waves from outside to second wiring lines42and third wiring lines44. This prevents faulty operations.

Touch panel100further includes first substrate35on which shield sections33and34are disposed. First electrodes31and first wiring lines32are disposed on the same plane as shield sections33and34on first substrate35. This enables to form shield sections33and34simultaneously with first wiring lines32if shield sections33and34are formed of conductive metal. When shield sections33and34are formed of a light-transmissive conductive material, they can be formed simultaneously with first electrodes31, typically by printing. As a result, fabrication is facilitated.

An average length of second wiring lines42is longer than an average length of first wiring lines32. In addition, an average length of third wiring lines44is longer than the average length of first wiring lines32. Accordingly, noise can be sufficiently suppressed even if shield sections33and34cover second wiring lines42and third wiring lines44but not cover first wiring lines32.

Furthermore, first electrodes31and second electrodes41configure operation area60when seen from the top. Multiple switch electrodes43are disposed such that they sandwich operation area60. As a result, switch electrodes43are disposed at a position easy for the user to operate.

As described above, shield sections33and34prevent entry of electromagnetic waves from outside to second wiring lines42and third wiring lines44in touch panel100in the exemplary embodiment.

INDUSTRIAL APPLICABILITY

The touch panel in the exemplary embodiment has a structure of disposing switch electrodes on the touch panel, and has a beneficial effect of suppressing electromagnetic waves entering from outside. Accordingly, this touch panel is effectively applicable mainly to various input devices.