Capacitive coordinate detection device

A coordinate detection device mounted on an information terminal apparatus is provided. The coordinate detection device includes a substrate that has a wiring region where leading lines to be connected to detection electrodes are located. The leading lines extend in a direction crossing an extension direction of the detection electrodes in the wiring region. The substrate is deformed such that the wiring region is distant from a surface.

This application claims the benefit of the Japanese Patent Application No. 2005-220440 filed on Jul. 29, 2005, which is hereby incorporated by reference.

BACKGROUND

A coordinate detection device mounted on an information terminal apparatus is provided.

2. Related Art

FIG. 8is a plan view of a capacitive coordinate detection device according to the related art. The capacitive coordinate detection device shown inFIG. 8has a base sheet121having a film shape formed of a dielectric. As shown inFIG. 8, a plurality of X detection electrodes101x,102x,103x,104x,105x, and106xextend in a Y direction and are disposed at predetermined gaps in an X direction (electrodes that extend in the Y direction and detect an X coordinate at a position where a conductor is brought into contact with or approaches the base sheet). A plurality of common electrodes101k,102k,103k,104k, and105kextend in the Y direction and are disposed between the X detection electrodes at predetermined gaps in the X direction and are provided on a rear surface of the base sheet121so as not to be brought into contact with each other. The common electrodes101k,102k,103k,104k, and105kare connected to one another at the end of the Y2side, and are led to the outside of the base sheet121as a common electrode K.

Further, as indicated by a broken line inFIG. 8, a plurality of Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108yextend in the X direction and are disposed in the Y direction at predetermined gaps (electrodes that extend in the X direction and detect a Y coordinate at a position where the conductor is brought into contact with or approaches the base sheet121) and are provided on a surface of the base sheet121. InFIG. 8, the common electrodes101k,102k,103k,104k, and105kdisposed on the rear surface of the base sheet121are indicated by solid lines.

The plurality of X detection electrodes101x,102x,103x,104x,105x, and106xdisposed on one surface of the base sheet121, and the plurality of Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108ydisposed on the other surface of the base sheet121are disposed to cross at right angles to each other on both surfaces of the base sheet121.

As shown inFIG. 8, a plurality of common branch electrodes122that extend toward both sides of the X direction in a straight line at a predetermined length are formed in the common electrodes101k,102k,103k,104k, and105k. The common branch electrodes122are disposed to cross the common electrodes101k,102k,103k,104k, and105kin the Y direction at predetermined gaps. The front ends of both directions (X1and X2directions) basically extend up to positions immediately before crossing the X detection electrodes101x,102x,103x,104x,105x, and106x.

As shown inFIG. 8, the X detection electrodes101x,102x,103x,104x,105x, and106xare correspondingly connected to leading lines101xa,102xa,103xa,104xa,105xa, and106xaat the end of the Y1side. The X detection electrodes101x,102x,103x,104x,105x, and106xare connected to a control IC (not shown) through the leading lines101xa,102xa,103xa,104xa,105xa, and106xa.

Further, the Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108yare correspondingly connected to leading lines101ya,102ya,103ya,104ya,105ya,106ya,107ya, and108yaat the end of the X1side. The Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108yare connected to the control IC (not shown) through the leading lines101ya,102ya,103ya,104ya,105ya,106ya,107ya, and108ya.

In the coordinate detection device120shown inFIG. 8, capacitance C is coupled between each of the plurality of common electrodes101k,102k,103k,104k, and105kand two electrodes adjacent to each common electrode among the X detection electrodes101x,102x,103x,104x,105x, and106x. If a voltage Vin of a pulse form is applied to each of the X detection electrodes101x,102x,103x,104x,105x, and106x, the voltage Vin is applied to each of the common electrodes101k,102k,103k,104k, and105kthrough capacitance C.

If a conductor comes into contact with or approaches the coordinate detection device120in a state where a finger or the like is grounded, charges applied between the common electrode101k,102k,103k,104k, and105kand the X detection electrodes101x,102x,103x,104x,105x, and106xare induced to the conductor, thereby reducing capacitance C. Accordingly, a detection voltage Vout depends on a change in capacitance C output from the X detection electrodes101x,102x,103x,104x,105x, and106x. The detection voltage Vout is changed according to a distance between the conductor and the X detection electrodes. It is possible to determine a coordinate position of the conductor in the X direction by sequentially detecting voltage values of the X detection electrodes101x,102x,103x,104x,105x, and106xat a predetermined cycle.

The plurality of common branch electrodes122formed in the common electrodes101k,102k,103k,104k, and105k, and the Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108yprovided between them are opposite to each other. Capacitance C is formed between the common branch electrode122and two adjacent Y detection electrodes in the Y direction in the same manner as the above. In the same manner as the X detection electrodes, if a pulse voltage Vin of a predetermined cycle is applied to the common electrode K and a detection voltage Vout output from the Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108yis sequentially detected at a predetermined cycle, it is possible to determine a coordinate position of the conductor in the Y direction.

The coordinate detection device120shown inFIG. 8is mounted on an information terminal apparatus fixed into a case of the information terminal apparatus in a state where the base sheet121is in a planar shape.

The configuration in which the capacitive coordinate detection device is mounted on the information terminal apparatus in the planar shape is disclosed in JP-A-2002-123363.

Similarly toFIG. 8, in a capacitive coordinate detection device120of the related art, as shown inFIG. 8, a gap between adjacent leading lines101xa,102xa,103xa,104xa,105xa, and106xais set to be smaller than a gap between the X detection electrodes101x,102x,103x,104x,105x, and106x. The leading lines101xa,102xa,103xa,104xa,105xa, and106xaextend to be close to an operation region that has the X detection electrodes101x,102x,103x,104x,105x, and106xin a direction that crosses the X detection electrodes.

If a conductor such as a finger or the like moves up to the end of the Y1direction in the operation region, the conductor approaches the leading lines101xa,102xa,103xa,104xa,105xa, and106xa, and then charges of the leading lines are induced to the conductor. An error may occur in position detection in an X coordinate direction.

The leading lines101ya,102ya,103ya,104ya,105ya,106ya,107ya, and108yaobliquely extend from the end of the X1side of the Y detection electrodes101y,102y,103y,104y,105y,106y,107y, and108y.

If the conductor moves up to the end of the X1direction in the operation region, since the conductor approaches the obliquely extending leading lines, an error may occur in position detection in a Y coordinate direction.

When the leading lines101xa,102xa,103xa,104xa,105xa, and106xaare provided to be spaced apart from the operation region or when the leading lines101ya,102ya,103ya,104ya,105ya,106ya,107ya, and108yaare provided to be spaced apart from the operation region, the erroneous detection can be reduced or prevented. The area of the base sheet121needs to be made large, and thus the size of the coordinate detection device120increases. Accordingly, the coordinate detection device cannot be properly mounted on a small information terminal apparatus.

SUMMARY

A coordinate detection device includes a substrate that is formed of an insulating material, and has a surface of an operation side, on which a conductor comes into contact with or approaches. A rear surface is also included that is opposite to the surface. A plurality of detection electrodes are located on the surface or the rear surface and extend in parallel in one direction. Common electrodes are located on the surface or the rear surface and are disposed at gaps from the detection electrodes.

Capacitance between the detection electrodes and the common electrodes is changed when the conductor comes into contact with or approaches the surface. The substrate has a wiring region where leading lines connected to the detection electrodes are located. The leading lines extend in a direction that crosses the extension direction of the detection electrodes in the wiring region. The substrate is deformed such that the leading lines are space away from the conductor coming into contact with the surface.

The detection electrodes may have X detection electrodes that are provided on one side of the surface and the rear surface of the substrate. Y detection electrodes are provided on the other surface and extend to cross the X detection electrodes. The substrate may have a wiring region where the leading lines to be connected to the X detection electrodes are located, and a wiring region where the leading lines to be connected to the Y detection electrodes are located. The substrate may be deformed such that at least one leading lines are distant from the conductor.

The substrate may be a flexible substrate, and the substrate may have a planar operation region where the detection electrodes and the common electrodes are located, and the wiring region. The flexible substrate may be bent through a bending line which is set at a boundary portion between the operation region and the wiring region.

In this case, a bending angle of the wiring region with respect to the operation region may be 90 degrees.

DESCRIPTION

Hereinafter, the preferred embodiments will be described with reference to the drawings.

FIG. 1shows an operation unit11of a cellular phone10generally as an information terminal apparatus. As shown inFIG. 1, a plurality of operation keys (operation members)12having typical key arrangement are arranged in the operation unit11. As shown inFIG. 2, the operation unit11has an upper case11A and a lower case11B, which are integrally combined. A plurality of aperture holes11A1are formed in the upper case11A. Key tops12athat are surfaces of the operation keys12are exposed from the aperture holes11A1toward the outside. Characters, symbols, figures or the like are printed in the key tops12a.

In the cellular phone10, a top surface11A2of the upper case11A, and the key tops12athat are surfaces of the operation keys12constitute an operation surface on which a conductor40such as a finger or the like comes into contact with or approaches.

The operation keys12are formed of a transparent or translucent synthetic resin. For example, the operation keys12are formed as a keymat integrally connected through a hoop portion (not shown). The operation keys12are connected to the keymat that serve as a main body side so as to be resiliently deformed in a Z1-Z2direction through the hoop portion.

A stem mat17formed of a transparent or translucent synthetic resin is formed below each of the operation keys12(a surface of the Z2side). A plurality of stems (compression convex portions)17ahaving columnar shapes integrally project in the stem mat17(a surface of the Z2side), and extend in a direction toward the inside of the device (the Z2direction).

The operation keys12are formed at positions opposite to the stems17ain a vertical direction (the Z1-Z2direction).

A circuit board13is fixed to the lower case11B. A plurality of electronic components15and light sources14are provided on the circuit board13. A front end of each of the stems17aopposite to the operation keys12in the vertical direction is disposed opposite to each of the electronic components15.

Each of the electronic components15has a metallic reversion plate having a dome shape and a contact electrode. A base end of the reversion plate is fixed to a ring-shaped electrode provided in the circuit board13. The inner surface of the reversion plate is opposite to the contact electrode. As the inner surface of the reversion plate is brought into contact with the contact electrode due to the reversion of the reversion plate, the reversion plate serves as a switch that makes the contact electrode and the ring-shaped electrode electrically connected to each other.

The light sources14can have LEDs or the like, and are provided around the electronic components15. When the operation key12is pressed, the reversion plate of the electronic component15can be reversed by the stem17a. It is possible to give a pleasant click feeling to an operator.

As shown inFIG. 2, a coordinate detection device20is provided within the operation unit11. The coordinate detection device20is fixed onto the bottom surface of the stem mat17by means of joining means (not shown) such as an adhesive or an adhesive tape.

FIG. 4is a plan view a base sheet and electrode patterns constituting the coordinate detection device20as viewed from a rear surface21d. The coordinate detection device20is mounted on the cellular phone10such that a surface21eopposite to the rear surface21dshown inFIG. 4is turned in an upward direction shown inFIGS. 2 and 3(the Z1direction), and the rear surface21dopposite to the surface21eis turned in a downward direction shown inFIGS. 2 and 3(the Z2direction).

As shown inFIGS. 2 and 3, the surface21eis opposite to an operation surface having the surface11A2and the key tops12awhich are surfaces of the operation keys12. The surface21ebecomes a surface of an operation side on which the conductor40is brought into contact with or approaches. Alternately, the coordinate detection device20may be mounted on the cellular phone10such that the rear surface21dis located in an operation region. The rear surface21dbecomes the surface of the operation side on which the conductor40is brought into contact with or approaches.

As shown inFIG. 4, the coordinate detection device20has a base sheet21has superior flexibility and a film shape. The base sheet21, which constitutes a substrate in the invention, is formed of an insulating material. As shown inFIGS. 2 and 4, insertion holes21athrough which the stems17apass, or passage holes21bserving as a passage that guides light emitted from the light sources14to the rear surface of the operation keys12through the stem mat17are formed in the base sheet21.

Mounting holes21cthat fix the base sheet21are formed. InFIG. 4, squares of a bold line indicate the insertion holes21a, and rectangles of a bold line indicate the passage holes21b. Circular holes indicate the mounting holes21c.

Since light emitted from the light sources14can pass through the passage holes21bas a passage, light can brightly shine the rear surfaces of the operation keys (operation members)12through the stem mat17formed of transparent resin or translucent resin. If the light sources14for illumination are disposed opposite to the passage holes21bformed in the base sheet21, the characters, symbols, figures or the like that are printed in the key tops12acan be clearly seen even in the dark.

The passage holes through which light from the light sources14passes may be formed in the stem mat17. In this case, the stem mat17may not be transparent or translucent. Further, the light sources14may not be formed. In this case, the stem mat17may not be transparent or translucent.

As shown inFIG. 4, a plurality of X detection electrodes1x,2x,3x,4x,5x, and6xthat extend in a Y direction and are disposed in an X direction at predetermined gaps (electrodes that extend in the Y direction and detect an X coordinate at a position where the conductor40is brought into contact with or approaches) are provided to be located on the rear surface21dof the base sheet21. Further, a plurality of common electrodes1k2k,3k,4k, and5k(common electrode K) that extend in the Y direction as a whole while keeping out of the insertion holes21aor the passage holes21bformed in the base sheet21are provided to be located at predetermined gaps in the X direction at positions where they are not brought into contact with the X detection electrodes1x,2x,3x,4x,5x, and6x.

InFIG. 4, solid lines that have no hatching indicate the X detection electrodes1x,2x,3x,4x,5x, and6xformed on the rear surface21dof the base sheet21, and solid lines having hatching indicate the common electrodes1k,2k,3k,4k, and5kformed on the rear surface21d.

As indicated by broken lines inFIG. 4and solid lines inFIG. 5, a plurality of Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8ythat extend in the X direction and are disposed at predetermined gaps in the Y direction (electrodes that extend in the X direction and detect a Y coordinate at a position where the conductor40is brought into contact with or approaches) are provided on the surface21eof the base sheet21to extend to cross the X detection electrodes1x,2x,3x,4x,5x, and6x.

The common electrode1khas common counter electrodes1k2,1k3,1k4,1k5,1k6,1k7, and1k8that extend in the Y direction and are partially opposite to the Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8y, respectively, in parallel. The common electrode1kextends in the Y direction at the left end. In the same manner, the common electrode2khas common counter electrodes2k1,2k2,2k3,2k4,2k5,2k6,2k7, and2k8that are partially opposite to the Y detection electrodes1yto8y, respectively, in parallel. In the same manner, the common electrode3khas common counter electrodes3k2,3k3,3k4,3k5,3k6,3k7, and3k8that are partially opposite to the Y detection electrodes1yto8y, respectively, in parallel.

The common electrode4khas common counter electrodes4k1,4k2,4k3,4k4,4k5,4k6,4k7, and4k8that are partially opposite to the Y detection electrodes1yto8y, respectively, in parallel. In the same manner, the common electrode5khas common counter electrodes5k2,5k3,5k4,5k5,5k6,5k7, and5k8that are partially opposite to the Y detection electrodes1yto8y, respectively, in parallel.

The common electrodes1k,2k,3k,4k, and5kare connected to the common counter electrodes1k8,2k8,3k8,4k8, and5k8on the Y2side. Leading lines28for ground extend from the end of the Y2side (the common counter electrode4k1) of the common electrode4kof the common electrode K (the common electrodes1k,2k,3k,4k, and5k), and are connected to a control IC (control unit)50, which will be described below.

In the common electrode1k, the common counter electrode1k8and the common counter electrode1k7that are adjacent to each other in the Y direction are connected to a common counter electrode1kaextending in the Y direction. The common counter electrode1k6and the common counter electrode1k5are connected to a common counter electrode1kb. The common counter electrode1k4and the common counter electrode1k3are connected to a common counter electrode1kc. The common counter electrode1k5and the common counter electrode1k4are connected to a common counter electrode1kc. A common counter electrode1kdextending in the Y direction is provided from the common counter electrode1k2. The common counter electrodes1ka,1kb,1kc, and1kdextending in the Y direction and the X detection electrode1xare partially opposite to each other, and a capacitance is formed between them.

A pair of the common counter electrode1k7and the common counter electrode1k6, a pair of the common counter electrode1k5and the common counter electrode1k4, and a pair of the common counter electrode1k3and the common counter electrode1k2are disposed opposite to each other in parallel, and form the same parallel electrodes.

A plurality of common branch electrodes22that extend in the X direction are formed in the X detection electrode1x. The common branch electrodes22are disposed opposite to each other between the parallel electrodes formed by the pair of the common counter electrodes, thereby forming a first capacitance adjustment unit.

A plurality of the common branch electrodes22extending in the X1and X2directions are formed in the X detection electrode2x. The common branch electrodes22are disposed opposite to each other between the parallel electrodes formed by the pair of the common counter electrodes in the common electrode1kor the common electrode2k, thereby forming a second capacitance adjustment unit.

In this case, if the common electrode1kis set as a reference common electrode BK, the X detection electrode1xcorresponds to a first detection electrode XR, and the X detection electrode2xcorresponds to a second detection electrode XL. Variations in comprehensive composite capacitance C between the reference common electrode (the common electrode1k) and the first detection electrode (the X detection electrode1x) and between the reference common electrode (the common electrode1k) and the second detection electrode (the X detection electrode2x) can be kept low by means of the first capacitance adjustment unit and the second capacitance adjustment unit, that is, composite capacitance C formed between the electrodes can be kept constant.

This relationship can be applied between other common electrodes and other X detection electrodes in the same manner.

In the Y detection electrode8ythat extends in the X direction linearly, capacitance is formed between the common counter electrodes1k8,3k8, and5k8located on the Y1side of the Y detection electrode8y. Capacitance is formed between the common counter electrodes2k8and4k8located on the Y2side of the Y detection electrode8y. Five common counter electrodes1k8,2k8,3k8,4k8, and5k8are alternately opposite to each other at locations on both sides of the Y detection electrode8y, and predetermined capacitance is formed between them.

In the same manner, in the Y detection electrode7yhaving detours26and26, five common counter electrodes1k7,2k7,3k7,4k7, and5k7are alternatively opposite to each other at locations on both sides of the Y detection electrode7y, and predetermined capacitance is formed between them. In the same manner, predetermined capacitance is also formed through five common counter electrodes in the Y detection electrodes6y,5y,4y,3y, and2y, excluding the Y detection electrode1y.

As shown inFIG. 4, the control IC50that applies a voltage of a predetermined sampling cycle between each of the X detection electrodes and the common electrode K and between each of the Y detection electrodes and the common electrode K and detects displacement of capacitance is provided in the base sheet21. Leading lines27extend from the ends of the Y2side up to connection terminals of the control IC50are formed in the X detection electrodes1x,2x,3x,4x,5xand6xformed on the rear surface21dof the base sheet21, respectively. The plurality of leading lines27extend to cross the X detection electrodes1x,2x,3x,4x,5x, and6x.

As shown inFIGS. 4 and 5, on the surface21eof the base sheet21, the Y detection electrodes1y,2y,3y, and4yare connected to the control IC50through leading lines29aextending from the ends of the X2side, and the Y detection electrodes5y,6y,7y, and8yare connected to the control IC50through leading lines29bthat extend from the ends of the X1side. The leading lines29aand the leading lines29bextend to cross the Y detection electrodes5y,6y,7y, and8y.

FIG. 5is a plan view that shows an electrode pattern of the Y detection electrodes formed on the surface21eof the base sheet21as viewed from the rear surface21d. Although the Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8yformed on the surface21eand the leading lines29aand29bhas to be indicated by broken lines, inFIG. 5, for a better understanding of the structure, the Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8yand the leading lines29aand29bare indicated by solid lines.

In the coordinate detection device20, if one of the plurality of common electrodes1k,2k,3k,4k, and5k, for example, the common electrode3k, is set as the reference common electrode, the X detection electrode located on one side (for example, the right side) adjacent to the reference common electrode3kbecomes4x, and the X detection electrode located on the other side adjacent to the reference common electrode3k(for example, the left side) becomes3x.

If a voltage Vin of a pulse form is applied to the X detection electrodes1x,2x,3x,4x,5x, and6xthrough an oscillation unit (not shown), predetermined capacitance C1is formed between the reference common electrode3kand the X detection electrode3x, and predetermined capacitance C2is formed between the reference common electrode3kand the X detection electrode4x.

If a distance d between the reference common electrode3kand the X detection electrode3xand an opposite length between the electrodes are the same as a distance d between the reference common electrode3kand the X detection electrode4xand an opposite length between the electrodes, respectively, the relationship C1=C2is established and a balance is adjusted between the electrodes.

In this embodiment, if the conductor40is brought into contact with or approaches on the surface21ehaving the reference common electrode3kformed thereon in a state where a finger or the like is grounded, charges applied between the reference common electrode3kand the X detection electrodes3xand4xare induced to the conductor, thereby reducing capacitance C1and C2. A detection voltage Vout that depends on the variations in capacitance C1and C2is output from the X detection electrodes3xand4x. The detection voltage Vout is output as a low voltage value as a distance between the conductor40and the X detection electrodes is close. Voltage values output from the X detection electrodes3xand4xare smallest, and voltage values output from other X detection electrodes1x,2x, and5xare large. It is possible to determine a coordinate position of the conductor40in the X direction within the surface21e(a position of an X coordinate of the conductor40within the rear surface21dwhen the coordinate detection device20is mounted on the cellular phone10such that the rear surface21dis located in the operation region) by sequentially detecting the voltage values of the X detection electrodes1x,2x,3x,4x,5x, and6xat a predetermined cycle.

Common counter electrodes1k2to1k8,2k1to2k8,3k1to3k8,4k1to4k8, and5k1to5k8are formed in the common electrodes1k,2k,3k,4k, and5k, respectively, so as to be partially opposite to the Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8y.

If one of the common counter electrodes1k2to1k8,2k1to2k8,3k1to3k8,4k1to4k8, and5k1to5k8is set to as a reference common electrode, capacitance C1and C2are also formed between the common electrode and adjacent Y detection electrodes in the Y direction. In the same manner as the X detection electrodes, if a pulse voltage Vin of a predetermined cycle is applied to the Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8yand a detection voltage Vout output from the Y detection electrodes1y,2y,3y,4y,5y,6y,7y, and8yis sequentially detected at a predetermined cycle, it is possible to determine a coordinate position of the conductor40in the Y direction (a position of the X coordinate of the conductor40within the rear surface21dwhen the coordinate detection device20is mounted on the cellular phone10such that the rear surface21dis located in the operation region).

The coordinate detection device20is configured to acquire the coordinate position of the X direction and the coordinate position of the Y direction, such that coordinate information of the conductor40can be input to the cellular phone10.

In the coordinate detection device20, as shown inFIG. 5, the leading lines29aare substantially bent at right angles with respect to the Y detection electrodes1y,2y,3y, and4yand extend in parallel with a side edge21hof the X1side of the base sheet21. The plurality of leading lines29aare densely disposed in a wiring region30formed at the side edge21h.

The leading lines29bare substantially bent at right angles with respect to the Y detection electrodes5y,6y,7y, and8yand extend in parallel with a side edge21iof the X2side of the base sheet21. The leading lines29bare densely disposed in a wiring region31formed at the side edge21i. However, the leading lines29aand29bdo not need to be densely disposed in the wiring regions30and31, respectively. For example, the leading lines29aand29bmay be sparsely disposed to be spaced at gaps from one another in the wiring regions30and31, respectively.

As shown inFIG. 4, the leading lines27and the leading lines28are substantially bent at right angles with respect to the X detection electrodes1x,2x,3x,4x,5x, and6xand extend in parallel with a front edge21fof the Y2side of the base sheet21. The plurality of leading lines27are densely disposed in a wiring region32formed at the front edge21f. However, the plurality of leading lines27do not need to be densely disposed in the wiring region32. For example, the plurality of leading lines27may be sparsely disposed to be spaced at gaps from one another in the wiring region32.

In the coordinate detection device20, as shown inFIG. 2, the wiring region30, in which the leading lines29aare formed, is deformed downward (the Z2direction shown inFIG. 2) so as to be distant from the conductor40. In the embodiment shown inFIG. 2, the wiring region30, in which the leading lines29aare formed, is bent downward at a bending angle of 90 degrees through a bending line30ashown inFIG. 5.

The wiring region31, in which the leading lines29bare formed, is deformed downward (the Z2direction shown inFIG. 2) so as to be distant from the conductor40. In the embodiment shown inFIG. 2, the wiring region31, in which the leading lines29bare formed, is bent downward at a bending angle of 90 degrees through a bending line31ashown inFIG. 5.

As shown inFIG. 3, the wiring region32, in which the leading lines27are formed, is deformed downward (the Z2direction shown inFIG. 3) so as to be distant from the conductor40. In the embodiment shown inFIG. 3, the wiring region32, in which the leading lines27are formed, is bent downward at a bending angle of 90 degrees through a bending line32ashown inFIG. 4.

In this embodiment, a region surrounded by the bending lines30a,31a, and32ais a planar operation region34. The operation region34is opposite in parallel to the operation surface of the cellular phone10having the top surface11A2of the upper case11A and the key tops12awhich are surfaces of the operation keys12. The bending lines30a,31a, and32aare set at boundary portions between the wiring regions30,31, and32and the operation region34.

In the embodiment shown inFIGS. 4 and 5, as shown inFIG. 4, the bending line30ais formed to pass through boundary portions between the ends of the Y detection electrodes1y,2y,3y, and4yat the side edge21hof the base sheet21and the leading lines29afrom the front edge21fof the base sheet21toward a back edge21g. Further, the bending line31ais formed to pass through boundary portions between the ends of the Y detection electrodes5y,6y,7y, and8yat the side edge21iof the base sheet21and the leading lines29bfrom the front edge21fof the base sheet21toward the back edge21g. Further, as shown inFIG. 4, the bending line32ais formed to pass through boundary portions between the ends of the X detection electrodes1x,2x,3x,4x,5x, and6xat the back edge21fand the leading lines27from the side edge21hof the base sheet21toward the side edge21i.

In the coordinate detection device20shown inFIGS. 2 to 5, the wiring regions30,31, and32, in which the leading lines27,29a, and29bare densely disposed, respectively, are bent downward (the Z2direction shown inFIGS. 2 and 3) from the bending lines30a,31a, and32ato be distant from the conductor40. As shown inFIGS. 2 and 3, distances L1, L2, and L5between the conductor40, which approaches the operation region34, and the leading lines27,29a, and29bcan be increased. As a result, the charges of the plurality of leading lines27, the plurality of leading lines29a, or the plurality of leading lines29bare rarely induced by the conductor, thereby preventing an erroneous coordinate detection operation.

InFIG. 2, the leading lines29aand29b, which are not bent downward, are indicated by one-dot-chain lines. Like the related art coordinate detection device, if the coordinate detection device is mounted on the cellular phone10while the base sheet21is in a planar shape, not bent, a distance L3between the conductor40scanning the operation surface and the leading lines29aand a distance L4between the conductor L4and the leading lines29bbecome shorter than the distances L1and L2in the coordinate detection device20, in which the leading lines29aand29bare bent downward. Therefore, the charges of the plurality of leading lines29aor the plurality of leading lines29bmay be induced by the conductor40.

FIG. 6is a detection curve that shows coordinate detection output results when the conductor40is moved on the surface21eof the base sheet21from the X1direction toward the X2direction while the position of the conductor40in the Y direction is constant in the related art coordinate detection device (having the structure indicated by a one-dot-chain line inFIG. 2), in which the base sheet21is not bent.FIG. 7is a detection curve showing coordinate detection output results when the conductor40is moved on the surface21eof the base sheet21from the X1direction toward the X2direction while the position of the conductor40in the Y direction is constant in the coordinate detection device20of the embodiment.

In the graphs shown inFIGS. 6 and 7, a horizontal axis indicates the detection position of the X coordinate of the conductor40, and a vertical axis indicates the detection position of the Y coordinate. Further, the left direction corresponds to the side edge21hof the base sheet21(the wiring region30), and the right direction corresponds to the side edge21iof the base sheet21(the wiring region31).

As shown inFIG. 6, in the related-art coordinate detection device, the X coordinate of the detection curve varies on the right and left sides. In the wiring region30and the wiring region31that are disposed on the left and right sides, erroneous detection is performed as if the conductor40is moved in the Y direction, regardless of the movement of the conductor40with the constant Y coordinate.

This is because the distance L3between the conductor40and the wiring region30is small, the conductor40may be simultaneously brought into contact with multiple leading lines among the leading lines29awhen the conductor40is close to the leading lines29aand29b, and the Y detection electrodes distant from the conductor40may perform erroneous detection due to the variation in the charges of the leading lines29a.

In the coordinate detection device that has the structure according to the related art, a region where linearity between an actual Y coordinate of the conductor40and the detection coordinate position is obtained has a range W1narrower than the width of the actual operation region34, as shown inFIG. 6.

In contrast, in the coordinate detection device20, as shown inFIG. 7, the detection curve is constant over the right side and the left side. On the sides where the leading lines29aand the leading lines29bare located, that is, the left and right sides in the drawing, the Y coordinate in the detection coordinates of the conductor40is output as a constant value.

Since the wiring regions30and31where the leading lines29aand29bare densely disposed are bent from the bending lines30aand31a, respectively, downward to be distant from the conductor40(the Z2direction shown inFIGS. 2 and 3), the distances L1and L2between the conductor40and the leading lines29aand29bcan be made large. The conductor40does not have an effect on the plurality of leading lines29aor the plurality of leading lines29b.

For this reason, in the coordinate detection device20, a region where linearity between the Y coordinate of the conductor40and the detection coordinate position is obtained becomes a range W2which is equal to the actual operation region34.

In the embodiment shown inFIG. 1, the coordinate detection device20is mounted on the cellular phone10. However, in recent years, with the reduction in size of the cellular phone10, the operation unit11is reduced in size. Accordingly, the area of the base sheet21of the coordinate detection device20needs to be reduced. However, in the coordinate detection device having the structure according to the related art, a ratio of the area where linearity is obtained (a region to be detected with high accuracy) is small. Accordingly, if only the region where linearity is obtained is set as the operation region, the operation region where the conductor40is brought into contact with or approaches is drastically narrowed.

Meanwhile, if the wiring regions30and31are formed at positions far away from the operation region, the area of the surface21eof the base sheet21needs to be increased. Accordingly, it is difficult to mount the coordinate detection device on the operation unit11with a reduced size.

In contrast, in the coordinate detection device20, a ratio of the area where linearity is obtained (a region to be detected with high accuracy) is increased. Therefore, even when the area of the base sheet21is reduced, the operation region where the conductor40is brought into contact with or approaches can be increased.

Therefore, the coordinate detection device20can be particularly adapted to be mounted on the latest cellular phone10with a reduced size.

Until now, the effects of the coordinate detection device20has been described by way of the wiring regions30and31, and the Y detection electrode3y, but the same description is applied to other Y detection electrodes1y,2y,4y,5y,6y,7y, and8y.

The positions of the wiring regions30,31, and32formed in the base sheet21are not limited. Further, in the embodiment shown inFIGS. 4 and 5, the leading lines27and28are formed in the wiring region32, but the leading lines27and28may be formed in other wiring regions.

In the embodiment shown inFIGS. 4 and 5, all the three leading lines27,29a, and29bare bent to be distant from the conductor29. However, if at least one of the three leading lines27,29a, and29bis bent, an area to be detected with high accuracy can be increased.

In the coordinate detection device20of the embodiment, the bending angle is not limited, but may be less than 90 degrees or more than 90 degrees. Preferably, the bending angle is set to 90 degrees because the distances L1, L2, and L5between the conductor40and the leading lines27,29a, and29bcan be increased.

In the embodiment shown inFIGS. 2 and 3, the wiring regions30,31, and32having the leading lines27,29a, and29bare bent downward through the bending lines30a,31a, and32a, respectively. However, the invention is not limited to this configuration. For example, the wiring regions30,31, and32having the leading lines27,29a, and29bmay be curved downward.

Although the cellular phone10is illustrated as an information terminal apparatus in the above description, the coordinate detection device20of the embodiment may be mounted on an information terminal apparatus, such as a personal computer or the like, other than the cellular phone10.

As described above, in the coordinate detection device20, the area of the detection region to be detected with high accuracy can be increased, as compared with the related art coordinate detection device. Therefore, mounting efficiency on an information terminal apparatus can be increased. In particular, the coordinate detection device can be properly mounted on the small cellular phone10.

In the coordinate detection device according to the embodiment of the invention, the substrate is deformed such that the wiring region where the leading lines to be connected to the detection electrodes are located is distant from the surface of the operation side of the substrate. Therefore, a distance between the conductor and the wiring region can be increased, and an influence of the leading lines in the wiring region on the detection operation due to the conductor can be prevented. Further, the planar shape of the coordinate detection device can be made small, and thus the coordinate detection device can be properly mounted on a small apparatus.