KR101094623B1 - Display device - Google Patents

Abstract

X electrodes XP and Y electrodes YP intersecting via the first insulating layer and a plurality of Z electrodes floating through each other are formed through the second insulating layer. As the second insulating layer, a material whose thickness is changed by pressure by touch is used. The Z electrode is disposed so as to overlap both the adjacent X electrode and the Y electrode. Further, the area becomes larger as the center of the X electrode is directed, and the area becomes smaller as the center of the adjacent X electrode is directed. Therefore, non-conductive input means can be used, and high-precision position detection can be performed with a small number of electrodes even if the touch area is small.

X electrode, Y electrode, Z electrode, insulating layer, pad part, slit, touch panel

Description

Display device {DISPLAY DEVICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and is particularly preferred for high precision of coordinate detection accuracy in a display device having a capacitive coupling type input device.

Input device (hereinafter referred to as touch sensor or touch panel) having a screen input function for inputting information by touch manipulation (contact pressure manipulation, hereinafter referred to simply as touch) using a user's finger or the like on a display screen The display device provided with) is used for mobile electronic devices such as PDAs and portable terminals, various home appliances, and stationary customer guide terminals such as unmanned receivers. As such an input device by a touch, a resistive film method for detecting a change in resistance value of a touched part, a capacitive coupling method for detecting a change in capacitance, an optical sensor method for detecting a change in light quantity of a part shielded by a touch, or the like This is known.

The capacitive coupling method has the following advantages when compared with the resistive film method or the optical sensor method. For example, the resistive film method or the optical sensor method is advantageous in that the transmittance is about 80%, whereas the capacitive coupling method is about 90%, which is advantageous in that the display quality is not deteriorated. In addition, in the resistive film method, since the touch position is detected by the mechanical contact of the resistive film, the resistive film may be deteriorated or damaged. In the capacitive coupling method, there is no mechanical contact such that the detecting electrode contacts the other electrode. It is also advantageous in terms of durability.

As a capacitive coupling touch panel, there exists a system as disclosed by patent document 1, for example. In this disclosed system, a vertical electrode for detection (X electrode) and a horizontal electrode for detection (Y electrode) arranged in a vertical and horizontal two-dimensional matrix shape are formed, and the capacitance of each electrode is detected by the input processing unit. When a conductor such as a finger comes into contact with the surface of the touch panel, the capacitance of each electrode increases, so the input processing unit detects this and calculates the input coordinates based on the signal of the capacitance change detected by each electrode. Here, even if the electrode for detection deteriorates and the resistance value which is a physical characteristic changes, since it has little influence on capacitance detection, there is little influence on the input position detection precision of a touch panel. Therefore, high input position detection precision can be realized.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2003-511799

However, since the capacitive coupling type touch panel detects a capacitance change of each electrode for detection and detects input coordinates as in Patent Document 1, a conductive material is assumed as an input means. Therefore, when a non-conductive resin stylus or the like used in a resistive film or the like is brought into contact with a touch panel of a capacitive coupling method, since the capacitance change of the electrode hardly occurs, there is a problem that the input coordinates cannot be detected. have.

On the other hand, when the stylus is made of a conductive material, for example, a metal, and the like is input to the touch panel of the capacitive coupling method, the number of electrodes increases. For example, consider a case where a capacitive coupling type touch panel having a diagonal of 4 inches and a dimension ratio of 3 to 4 is realized in an electrode shape based on a rhombus like Patent Document 1. In the case where the finger is an input object, the minimum contact surface is assumed to be 6 mm in diameter, and if the electrode for detection is prepared with this size as the electrode interval, the total number of electrodes is 22. On the other hand, assuming that the contact surface of the stylus is 1 mm in diameter, and the detection electrodes are prepared with this size as the electrode interval, the number is 139, which increases the number of electrodes by about six times. Increasing the number of electrodes increases the liquid smoke area required for wiring circumference to the input processing section, and also increases the number of signal connections with the control circuit, thereby deteriorating reliability against impacts. In addition, since the number of terminals in the input processing section increases, the circuit area also increases, and an increase in cost is concerned.

In view of the above, in the capacitive coupling type touch panel disclosed in Patent Document 1, the number of electrodes in the case of responding to an input by a non-conductive material and an input means of a small contact surface is a problem.

In order to solve the above problem, in the present invention, a capacitive touch panel having a plurality of X electrodes, a plurality of Y electrodes, and a plurality of Z electrodes is used. In this capacitive touch panel, a plurality of X electrodes which extend in a first direction in the first plane and are arranged so that the thin wire portions are alternately arranged, and in a second plane, extend in a second direction crossing the first direction A plurality of Y electrodes formed by alternately arranging the thin wires, a plurality of Z electrodes electrically floating in a third plane, a first insulating layer disposed between the X electrode and the Y electrode, and the Y And a second insulating layer disposed between the electrode and the Z electrode, wherein the X electrode and the Y electrode cross each other through the first insulating layer, and when viewed in plan, the pad portion of the X electrode and The pad portion of the Y electrode is disposed so as not to overlap, and the Z electrode is formed so as to overlap both the adjacent X electrode and the Y electrode when viewed in plan. At this time, the second insulating layer is formed of a material whose thickness is changed by pressing by touch, for example, an elastic insulating material, so that the X electrode, the Y electrode, and the Z electrode are also used for non-conductive input means. It is possible to generate a capacitance change in between, and thus it becomes possible to detect a touch by the capacitive coupling method.

The pad portion of the X electrode extends to the vicinity of the thin wire portion of the X electrode adjacent to the X electrode, and in a plan view, the shape at the pad portion of the X electrode faces the thin wire portion of the X electrode. The area becomes larger according to the present invention, and the area becomes smaller as the thin wire portion of the adjacent X electrode is directed. This makes it possible to calculate the touch coordinate position from the ratio of the detection capacitance components of the adjacent X electrodes even when the electrode spacing of the X electrodes is wider than the contact surface in the touch operation, so that the precision is small with the small number of electrodes. Position detection becomes possible.

Further, the plurality of Z electrodes are formed by overlapping both of the adjacent X electrodes and the Y electrodes, so that even if a contact surface by touch exists on the X electrodes, the Y electrodes adjacent through the Z electrodes are formed. The electrode can detect the change in capacitance, and on the contrary, even if a contact surface by touch is present on the Y electrode, the X electrode adjacent through the Z electrode can detect the change in capacitance, so that the entire touch panel can be detected. Input coordinates can be detected at. At the same time, the number of electrodes of the Y electrode can also be reduced.

According to the present invention, by studying the shape and arrangement of the electrodes of the touch panel, it is possible to detect a position with a higher precision than in the past with a small number of electrodes.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail using drawing.

Example 1

1 shows a configuration of an input device (hereinafter referred to as a touch panel) and a display device provided with the same.

In FIG. 1, reference numeral 101 denotes a touch panel according to the first embodiment of the present invention. The touch panel 101 has an X electrode XP and a Y electrode YP for capacitive detection. Here, for example, four X electrodes (XP1 to XP4) and four Y electrodes (YP1 to YP4) are shown, but the number of electrodes is not limited thereto. The touch panel 101 is installed on the entire surface of the display device 106. Therefore, when the user sees an image displayed on the display device, since the display image needs to pass through the touch panel, the touch panel preferably has a high transmittance. The X electrode and the Y electrode of the touch panel 101 are connected to the capacitance detecting unit 102 by the detection wiring. The capacitance detection unit 102 is controlled by a detection control signal output from the control operation unit 103, detects the capacitance of each electrode (X electrode, Y electrode) included in the touch panel, and measures the capacitance of each electrode. The changing capacitance detection signal is output to the control calculating section 103. The control calculation unit 103 calculates a signal component of each electrode from the capacitance detection signal of each electrode, and calculates and calculates input coordinates from the signal component of each electrode. When the input coordinates are transmitted from the touch panel 101 by a touch operation, the system 104 generates a display image according to the touch operation and transmits it to the display control circuit 105 as a display control signal. The display control circuit 105 generates a display signal in accordance with the display image transmitted by the display control signal, and displays the image on the display device.

2 shows a circuit configuration of the capacitance detector 102. Here, as an example, a capacitance detection circuit by current integration is shown. However, the capacitive detection method is not limited thereto, for example, a capacitive detection method by a switched capacitor using a capacitor and a switch, or a charge transfer method in which charges are transferred to a capacitor using a switch and a capacitor in the same manner. As long as it is a system which can detect the capacitance or the capacitance change of the electrode for capacitance detection of a panel, it is applicable to embodiment of this invention. The capacitance detection circuit by the current integration shown in FIG. 2 includes a constant current source, a switch SW_A for applying current from the constant current source to the X electrode and the Y electrode of the touch panel 101, and an electrode for capacitance detection during current integration. The comparator 107 compares the voltage VINT and the reference voltage VREF with the voltage VINT, and the switch SW_B for resetting the voltage of the capacitance detecting electrode. Here, the switches SW_A, SW_B and its control signals connected to the X electrode XP are described as SW_XPA and SW_XPB, and the switches SW_A, SW_B and their control signals connected to the Y electrode YP are described as SW_YPA and SW_YPB. .

3 is a timing chart showing the operation of the capacitance detecting unit 102 shown in FIG. It is assumed here that the switch is in the connected state when the control signal is at the high level, and the switch is in the unconnected state when the control signal is at the low level. The capacitance detecting unit 102 sets the SW_XP1B to the low level to cancel the reset state, and connects the constant current source and the XP1 electrode with the SW_XP1A to the high level. As a result, the voltage VINT of the electrode XP1 for capacitance detection of the touch panel 101 increases. The reference voltage VREF is set at a higher potential than the reset potential (assuming GND here). Therefore, the output of the comparator 107 goes to the low level until SW_XP1A goes high and until VINT reaches VREF. When VINT becomes equal to or higher than the reference voltage VREF, the comparator 107 outputs a high level. Thereafter, the comparator 107 outputs a high level until the SW_XP1A is in the non-connected state and the SW_XP1B is in the connected state until the XP1 electrode is reset. After the above-described charge and discharge of the XP1 electrode is completed, charge and discharge of the XP2 electrode is then similarly performed. This operation is repeated to detect the capacitance of the electrodes XP1 to XP4 and YP1 to YP4. By repeating the above operation, input coordinates can be detected continuously. 4 is a diagram showing the voltage VINT of the XP1 electrode when the capacitance of the capacitance detecting electrode of the touch panel 101 is changed by capacitance detection by the current integration shown in FIGS. 2 and 3. When there is no touch on the XP1 electrode of the touch panel 101, the capacitance of the XP1 electrode does not change, so the time until the reference voltage VREF is reached is almost constant for each detection operation. On the other hand, when there is a touch on the XP1 electrode, the capacitance of the XP1 electrode is changed. Here, for example, assuming that the capacitance is increased, since the current of the constant current source is constant, the time until reaching the reference voltage VREF becomes long. The control calculating part 103 can detect the difference of the arrival time to the reference voltage VREF by this touch situation as the difference of the rise timing of a capacitance detection signal. Therefore, the control calculating part 103 can calculate the difference of the rise timing of a capacitance detection signal as a signal component of each electrode, and can calculate an input coordinate from the signal component of each electrode.

Next, the electrode for capacitance detection formed in the touch panel 101 which concerns on 1st Embodiment of this invention is demonstrated using FIG. 5A, FIG. 5B, and FIG.

5A is a diagram showing electrode patterns of the X electrodes XP and Y electrodes YP for capacitive detection of the touch panel 101, and the Z electrodes ZP formed thereon. The X electrode XP and the Y electrode YP are connected to the capacitance detecting unit 102 by the detection wiring. On the other hand, the Z electrode ZP is not electrically connected and is in a floating state. FIG. 5B shows only the electrode patterns of the X electrode XP and the Y electrode YP in the figure. The Y electrodes extend in the horizontal direction of the touch panel 101, and a plurality of Y electrodes are arranged in the vertical direction. The intersection of the Y electrode and the X electrode narrows the electrode widths of the Y electrode and the X electrode in order to reduce the cross capacitance of each electrode. This part is temporarily called thin line. Therefore, the Y electrode has a shape in which thin wire portions and other electrode portions (hereinafter referred to as pad portions) are alternately arranged in the extending direction. An X electrode is disposed between adjacent Y electrodes. The X electrodes extend in the longitudinal direction of the touch panel 101, and a plurality of X electrodes are arranged in the lateral direction. Like the Y electrode, the X electrode has a shape in which the thin wire portion and the pad portion are alternately arranged in the extending direction. Hereinafter, in order to explain the shape of the pad portion of the X electrode, it is assumed that the wiring position (or the thin wire portion of the X electrode) for temporarily connecting the X electrode to the detection wiring is the center of the X electrode in the horizontal direction. The electrode shape of the pad portion of the X electrode becomes smaller as it approaches the center of the adjacent X electrode, and the area becomes larger as it is closer to the center of the X electrode. Therefore, when considering the area of the X electrode between two adjacent X electrodes, for example, XP1 and XP2, the electrode area of the pad portion of the XP1 electrode is maximized near the center of the XP1 electrode, and also the pad of the XP2 electrode. The negative electrode area is minimized. On the other hand, in the vicinity of the center of the XP2 electrode, the electrode area of the pad portion of the XP1 electrode is minimum, and the electrode area of the pad portion of the XP2 electrode is maximum. Here, the shape of the pad portion between two adjacent X electrodes is characterized in that the shape of one X electrode is convex, and the shape of the other X electrode is concave.

In FIG. 5B, although the electrode shape of the pad part of the X electrode left side is convex shape, and the electrode shape of the right side is concave shape, it is not limited to this. For example, the electrode shape on the right side of the X electrode may be convex and the electrode shape on the left side may be concave, the electrode shapes on the left and right of the X electrode may be convex, and the electrode shape of the adjacent X electrode is concave. You may also

Next, the shape of the Z electrode ZP will be described. In FIG. 5A, the Z electrode ZP is divided into a plurality of electrodes ZP by a plurality of slits parallel to the Y electrode and a plurality of slits parallel to the X electrode. In Fig. 5A, the longitudinal position of the slit parallel to the Y electrode is formed on each X electrode and each Y electrode, and the longitudinal position of the slit on each X electrode is near the apex of the convex shape of the X electrode shape, Or it is preferable to set it as the vicinity of a concave valley. In addition, it is preferable that the longitudinal position of the slit on each Y electrode should be near the center of the electrode width of a Y electrode. On the other hand, the number of slits parallel to the X electrode is formed in plural places between adjacent X electrodes. Although the space | interval of the slit parallel to the X electrode at that time can be arbitrarily set, it is preferable that it is close to the dimension of the minimum contact surface of the assumed input means.

FIG. 6 is a cross-sectional view of the touch panel 101 from point A to point B in FIG. 5A. In this cross section, only the layers required for the explanation of the touch panel operation are shown. Each electrode of the touch panel 101 is formed on a transparent substrate. The order from the layer closest to the layer farther from the transparent substrate will be described in order. First, the X electrode XP is formed at a position near the transparent substrate, and then an insulating film for insulating the X electrode and the Y electrode is formed. Then, the Y electrode YP is formed. Here, the order of the X electrode XP and the Y electrode may be replaced. After the Y electrode YP, an insulating layer for pressure detection is arranged, and then a Z electrode ZP and a protective layer are formed. The pressure detecting insulating layer may be a transparent insulating material whose film thickness is changed at the time of pressing by touch operation. For example, an insulating layer for pressure detection may be formed using an elastic insulating material or the like.

Next, the capacitance change at the time of touch operation in the touch panel 101 according to the first embodiment of the present invention will be described with reference to FIGS. 7A, 7B, 8A, and 8B.

7A and 7B are schematic diagrams for describing capacitance changes when the input means for touch operation is a conductor such as a finger. It is assumed here that the pressure at the time of touch is small so that the thickness of the pressure detection insulating layer does not change. In addition, although the electrode capacitance of each electrode becomes a combined capacitance with a fringe capacitance with an adjacent electrode, a cross capacitance, and other parasitic capacitance, only the parallel plate capacitance with a Z electrode is noted here, and the other electrode capacitance is touched. It is assumed that there is no change in operation and in the absence of touch operation. Here, assume that the capacitance between the Z electrode ZPA and the X electrode XP1 in the absence of a touch operation is Cxz, and the capacitance between the Z electrode ZPA and the Y electrode YP2 is Cyz.

When the capacitance detecting unit 102 detects the electrode capacitance of the X electrode XP1, the Y electrode YP2 is reset to the GND potential. Therefore, since the Z electrode ZPA is floating, the combined capacitance in the case seen from the X electrode XP1 becomes the capacitance of the series connection of Cxz and Cyz. The synthesized capacitance Cxp of the X electrode at this time is expressed by the following equation.

On the other hand, when a finger touches by touch operation, it can be regarded as a state in which the electrostatic capacitance component Cf of the finger is electrically connected to the Z electrode ZPA. In the case where the synthesized capacitance in this case is represented by an equivalent circuit, it becomes Fig. 7B, and the synthesized capacitance Cxpf of the X electrode during touch operation is expressed by the following equation.

The control operation unit 103 calculates the difference between the XP1 electrode capacitance Cxp when there is no touch operation and the XP1 electrode capacitance Cxpf when there is a touch operation as the signal component of the XP1 electrode. The difference ΔCxp of the electrode capacitance with or without touch operation can be calculated from the equations (1) and (2).

As can be seen from Equation 3, since the difference ΔCxp of the electrode capacitance depends on the capacitance Cf of the finger, the control calculation unit 103 can calculate the signal component of the XP1 electrode.

8A and 8B are schematic diagrams illustrating capacity change when the input means for touch operation is non-conductive and the thickness of the pressure detection insulating layer is changed by pressure during touch. The capacitance of the XP1 electrode when there is no touch operation can be represented by Equation 1 as described with reference to FIGS. 7A and 7B. 8A and 8B are diagrams in the case where the pressure detection insulating layer between the Z electrode ZPA and the capacitance detecting electrode is thinned by the pressure during touch. In this case, when the capacitance between the Z electrode ZPA and the X electrode XP1 is set to Cxza, and the capacitance between the Z electrode ZPA and the Y electrode YP2 is set as Cyza, the parallel plate capacitance is inversely proportional to the thickness.

When the capacitance detecting unit 102 detects the electrode capacitance of the X electrode XP1, the Y electrode YP2 is reset to the GND potential. Therefore, since the Z electrode ZPA is floating, the combined capacitance in the case seen from the X electrode XP1 becomes the capacitance of the series connection of Cxza and Cyza. The synthesis capacitance Cxpa of the X electrode at this time is expressed by the following equation.

The control calculation unit 103 calculates the difference between the XP1 electrode capacitance Cxp when there is no touch operation and the XP1 electrode capacitance Cxpa when there is a touch operation as the signal component of the XP1 electrode. The difference ΔCxpa of the electrode capacitance with or without touch operation can be calculated from the equations (1) and (5).

As can be seen from the equations (4) and (6), since the difference detector ΔCxpa of the electrode capacitance can be detected by the capacitance detection unit 102, the control calculation unit 103 can calculate the signal component of the XP1 electrode. have.

In view of the above, by using the pressure detecting insulating layer and the Z electrode ZP, even if it is a non-conductive input means, the thickness of the pressure detecting insulating layer is changed by pressure, so that the input coordinates can be detected by the change in capacitance. .

Next, with reference to FIGS. 9A-9D and FIG. 10, the signal component of each electrode in the case where the position of a contact surface changes to a horizontal direction when a contact surface by touch operation is small is demonstrated.

FIG. 9A shows a state where the contact surface is changed on the X electrode between two adjacent X electrodes XP2 and XP3. XA is near the center of XP2, XB is near the middle of XP2 and XP3, and XC is near the center of XP3. In FIG. 9A, the Z electrode ZP is not shown for the sake of simplicity. 9B is a diagram showing signal components calculated by the control computing unit 103 of XP2 and XP3 when the position of the contact surface is XA. Similarly, Fig. 9C shows the signal components of XP2 and XP3 at the position XB, and Fig. 9D, respectively. The capacitance change between the capacitance Cf described in FIGS. 7A and 7B or the Z electrode ZP and the capacitance detection electrode described in FIGS. 8A and 8B depends on the area of the contact surface. Therefore, when the area where the electrode for capacitance detection and the contact surface overlap is large, the signal component becomes large. On the contrary, when the area where the electrode for capacitance detection electrode and the contact surface overlaps is small, the signal component becomes small. In the position XA, since the contact surface and XP2 overlap with each other and hardly overlap with XP3, as shown in Fig. 9B, the signal component of XP2 is large and the signal component of XP3 is small. In the position XB, the area where the contact surfaces of XP2 and XP3 overlap with each other is almost the same, so that the signal components calculated as shown in Fig. 9C are almost the same in XP2 and XP3. Further, in the position XC, since the contact surface and the XP3 overlap with each other and hardly overlap with the XP2, as shown in Fig. 9D, the signal component of the XP3 is large and the signal component of the XP2 is small. The control calculating part 103 calculates the center of gravity using the signal component of each electrode, and calculates the input coordinate which the contact surface touched by touch operation. When signal components of the same degree are obtained in XP2 and XP3 as shown in Fig. 9C, since the center of gravity position is between the XP2 electrode and the XP3 electrode, the input coordinates can be calculated. On the other hand, when the signal component of one X electrode is very large as shown in Figs. 9B and 9D, since the center of gravity position is near the X electrode where the large signal component is detected, the input coordinates can be similarly calculated.

FIG. 10 shows a state where the contact surface is changed on the Y electrode as in FIG. 9A. The position in the lateral direction corresponds to XA 'in Fig. 9A, XB's XB', and XC's XC '. In FIG. 10, the contact surface does not directly overlap with the X electrode, but the Z electrode ZP having the contact surface overlaps with the adjacent X electrodes XP2 and XP3. Therefore, the change in capacitance due to contact on the Y electrode can be detected also in adjacent X electrodes by the capacitive coupling through the Z electrode ZP.

As described above, by using the electrode shape of the X electrode according to the first embodiment of the present invention, the center of gravity can be calculated even when the electrode spacing of the X electrode is larger than the contact surface, and the position can be detected with high accuracy. Done. Therefore, it is possible to reduce the number of electrodes compared to the conventional electrode pattern by widening the electrode spacing of the X electrodes relative to the contact surface. In addition, even if the electrode shape of the X electrode is discrete with the Y electrode interposed therebetween, the electrically floating Z electrode is arranged to span the adjacent X electrode and the Y electrode, thereby detecting input coordinates in the X direction on the entire touch panel. It becomes possible.

Next, with reference to FIGS. 11A-11D, the signal component of each electrode in the case where the position of a contact surface changes to a vertical direction when a contact surface by touch operation is small is demonstrated.

Fig. 11A shows a state in which the position of the contact surface is changed in the longitudinal direction between two adjacent Y electrodes YP2 and YP3. YA is near the center of YP2, YB is near the middle of YP2 and YP3, and YC is near the center of YP3. When the contact surface is the position YA, since the Y electrode overlapping with the contact surface is only YP2, the signal component detected by the control calculating section 103 is only the signal component of the YP2 electrode as shown in Fig. 11B. Similarly, in the case where the contact surface is the position YC, since the Y electrode overlapping with the contact surface is only YP3, as shown in FIG. 11D, only the signal component of the YP3 electrode is used. On the other hand, when the contact surface is on the X electrode like the position YB, the Z electrode ZP overlapping the contact surface intersects with the adjacent Y electrode. Therefore, the capacitance change due to the contact on the X electrode can be detected at the adjacent Y electrodes by the capacitive coupling through the Z electrode ZP. In the case of the position YB, the capacitance change occurring at the Z electrode ZP crossing the YP2 electrode and the capacitance change occurring at the Z electrode ZP crossing the YP3 electrode are approximately equal. Therefore, as shown in Fig. 11C, the signal components obtained in YP2 and YP3 are approximately the same. The control calculation unit 103 calculates the center of gravity using the signal component of each electrode as in the case of the calculation of the input coordinates of the X electrodes, and calculates the input coordinates that the contact surface touches by touch operation. When signal components of the same degree are obtained in YP2 and YP3 as shown in Fig. 11C, the input center can be calculated because the center of gravity position is between the YP2 electrode and the YP3 electrode. On the other hand, in the case of only the signal component of one Y electrode as shown in Figs. 11B and 11D, since the center of gravity position becomes near the center of the Y electrode which detected the signal component, the input coordinates can be similarly calculated.

As described above, the electrode shape of the Y electrode according to the first embodiment of the present invention is arranged so that the electrically floating Z electrode spans the adjacent X electrode and the Y electrode even though the electrode shape is discretely interposed between the X electrode. It is possible to detect input coordinates in the Y direction on the entire touch panel. In addition, since the input coordinates in the longitudinal direction of the region where the X electrodes are present can be detected by using the above-described Z electrodes, it is possible to reduce the number of Y electrodes. In addition, the coordinate calculation by the center of gravity calculation is possible also in the vertical Y coordinate, and it becomes possible to detect a position with high precision.

Since the effect of reducing the number of electrodes for capacitance detection by the shape of the electrodes of the X electrode, the Y electrode, and the Z electrode in the first embodiment of the present invention described above is shown, a diagonal 4 inch ( The number of electrodes in the touch panel (assuming aspect ratio of 3 to 4) was calculated. Here, the minimum contact surface assumed is assumed to be 1.0 mm in diameter, and the electrode spacing of the Y electrodes was 2.0 mm. FIG. 13 shows a graph incorporating the number of electrodes when the electrode spacing of the X electrodes is used as a parameter. By increasing the electrode spacing of the X electrodes, the number of X electrodes can be reduced. For example, by setting the electrode interval to 6.0 mm, the number of electrodes for capacitance detection is reduced by about 100 for 139 electrodes in the prior art (when both the X electrode and the Y electrode are arranged at an electrode interval of 1.0 mm). It becomes possible.

According to the first embodiment of the present invention, by reducing the number of electrodes for capacitance detection, the liquid lead dimension for the detection wiring circumference can be reduced. In addition, since the number of connections between the touch panel 101 and the capacitance detecting unit 102 is reduced, reliability improvement can also be expected. In addition, since the number of electrodes for capacitance detection is reduced, the number of terminals of the capacitance detection unit can also be reduced, thereby making it possible to reduce the cost at the time of ICization.

14 and 15 show the case where the position of the slit of the Z electrode is changed. 5A, 14, and 15, the slits parallel to the X electrode are the same, and the slits parallel to the Y electrode are different. However, the point where the Z electrode intersects the adjacent X electrode and the Y electrode is common.

In Fig. 14, slits parallel to the Y electrodes are disposed near the center of each Y electrode. As a result, since the same Z electrode intersects the adjacent X electrode and the Y electrode, the Y electrode can be detected by coupling the capacitance change on the X electrode as in the case of FIG. 5A, and conversely, the capacitance change on the Y electrode is reversed. The X electrode can be detected by the coupling. For this reason, the same effect as FIG. 5A can be expected.

In Fig. 15, slits parallel to the Y electrodes are arranged near the center of each X electrode. As a result, since the same Z electrode intersects the adjacent X electrode and the Y electrode, the Y electrode can be detected by coupling the capacitance change on the X electrode as in the case of FIG. 5A, and conversely, the capacitance change on the Y electrode is reversed. The X electrode can be detected by the coupling. For this reason, the same effect as FIG. 5A can be expected.

FIG. 16 is a case where the shape of the X electrode shown in FIG. 5B is changed. 5B and 16, the shape of the Y electrode is the same. In FIG. 5B, the X electrode has a concave shape and a convex shape. However, FIG. 16 is a shape that is nearly triangular. 5B and 16 are the same in that the area becomes smaller as they are closer to the center of the adjacent X electrodes, and the area is larger as they are closer to the center of the X electrodes. Therefore, the same effect as that of FIG. 5B can be expected. The shape of the X electrode is not limited to the shapes of FIGS. 5B and 16 as long as the area becomes smaller as it approaches the center of the adjacent X electrode, and the area becomes larger as it is closer to the center of the X electrode.

As described above, according to the embodiment of the present invention, even when the non-conductive input means is in contact with the touch panel, the distance between the X electrode and the Y electrode for capacitance detection and the Z electrode thereon is changed. Since the capacitance change can be caused, the input coordinate can be detected as the capacitive coupling method. This makes it possible to cope with the resin stylus used in the resistive film type, and the barrier of substitution with the resistive film type touch panel is lowered.

In addition, the number of X electrodes is reduced by studying the electrode shape so that the input position between adjacent X electrodes can be calculated by the signal ratio of the capacitance change obtained from two adjacent X electrodes. Can be reduced by studying. As a result, the liquid lead width required for the circumferential wiring from the detection electrode to the input processing portion can be narrowed, and the likelihood of designability is improved. In addition, since an increase in the number of terminals of the input processing unit can be suppressed, a capacitive coupling type touch panel capable of detecting the input position with high precision at low cost can be realized. In addition, since input coordinates with a small contact surface, for example, a stylus or the like, can be detected with high accuracy, the present invention can also be applied to applications such as character input.

1 is a system configuration diagram of an input device according to an embodiment of the present invention and a display device provided with the same;

2 is a circuit configuration diagram of the capacitance detector 102.

3 is a timing chart for explaining the operation of the capacitance detector 102. FIG.

4 is a voltage waveform diagram of a capacitance detection electrode at the time of capacitance detection.

5A and 5B are plan views showing electrode shapes of the touch panel in the embodiment of the present invention.

6 is a cross-sectional view showing an electrode structure of a touch panel in the embodiment of the present invention.

7A and 7B are schematic diagrams illustrating capacitance changes due to capacitance of a capacitance detecting electrode in a touch panel in an embodiment of the present invention.

8A and 8B are schematic diagrams illustrating capacitance changes caused by changes in thickness of the pressure detection insulating layer of the capacitance detection electrode in the touch panel in the embodiment of the present invention.

Fig. 9A is a diagram showing the positions of a plurality of contact surfaces in the X direction on the X electrode, and Figs. 9B to 9D are graphs showing signal components of XP2 and XP3 at each position of Fig. 9A.

10 is a diagram showing positions of a plurality of contact surfaces in the X direction on the Y electrode.

Fig. 11A is a diagram showing the positions of a plurality of contact surfaces in the Y direction on the Y electrode, and Figs. 11B to 11D are graphs showing signal components of XP2 and XP3 at each position of Fig. 11A.

12 is a layout view of electrodes for capacitance detection in a touch panel.

Fig. 13 is a graph showing the dependence of the X electrode interval on the number of electrodes for capacitance detection.

14 is a schematic diagram showing the shape of another Z electrode in the embodiment of the present invention.

FIG. 15 is a schematic diagram showing the shape of another Z electrode in the embodiment of the present invention. FIG.

FIG. 16 is a schematic diagram showing the shape of another X electrode in the embodiment of the present invention. FIG.

<Explanation of symbols for the main parts of the drawings>

XP: X electrode for capacitance detection

YP ': Y electrode for capacitance detection

101: touch panel

102: capacity detection unit

103: control operation unit

104: system CPU

105: display control circuit

106: display device

107: comparator

SW_A, SW_B: switch, and its control signal

VINT: Current-integrated voltage of the electrode for capacitance detection

VREF: reference voltage

ZP, ZPA: Z electrode

Cf: capacitance

Cxz, Cxza: Capacitive component between X electrode and Z electrode

Cyz, Cyza ': Capacitive component between Y electrode and Z electrode

XA, XB, XC: Contact surface position

XA '， XB' ， XC ': contact surface position

YA, YB, YC: Contact surface position

Claims (13)

A display device comprising a capacitive touch panel that detects touch position coordinates on a display area by a capacitive coupling method. The capacitive touch panel, A plurality of X electrodes extending in a first direction and formed by alternately arranging pad portions and thin wire portions; A plurality of Y electrodes extending in a second direction in a second plane and crossing the first direction, the pads and the thin wires being alternately arranged; A plurality of Z electrodes electrically floating in the third plane, A first insulating layer disposed between the X electrode and the Y electrode; A second insulating layer disposed between the Y electrode and the Z electrode, The X electrode and the Y electrode intersect with each other via the first insulating layer; In the plan view, the pad portion of the X electrode and the pad portion of the Y electrode are disposed not to overlap, And the Z electrode is formed so as to overlap both of the adjacent X electrode and the Y electrode when viewed in plan view. The method of claim 1, The second insulating layer is a display device, characterized in that the thickness of the second insulating layer is changed by pressing by touch. 3. The method of claim 2, And the second insulating layer is formed of an elastic insulating material. The method of claim 1, The pad portion of the X electrode extends to the vicinity of the thin wire portion of the X electrode adjacent to the X electrode, In the plan view, the shape of the pad portion of the X electrode is larger in area as it faces the thin wire portion of the X electrode, and smaller in area as it faces the thin wire portion of the adjacent X electrode. Display device. 5. The method of claim 4, In the plan view, the width of the pad portion of the Y electrode is constant with respect to the direction in which the Y electrode extends, And the pad portion of the X electrode and the pad portion of the Y electrode are alternately disposed in a direction in which the X electrode extends when viewed in plan view. The method of claim 5, The pad part of two adjacent said X electrodes WHEREIN: The shape of the pad part of one side is convex shape, and the shape of the pad part of the other side is concave shape. The method of claim 5, In the pad portions of two adjacent X electrodes, the shape of both of the pad portions is a convex shape. The method of claim 5, And the Z electrode is divided by a plurality of slits in the extending direction of the X electrode, and further divided by a plurality of slits in the extending direction of the Y electrode. The method of claim 8, And one slit of the Z electrode along the direction in which the Y electrode extends is formed one on the Y electrode and one on the X electrode in plan view. The method of claim 8, And one slit of the Z electrode along the direction in which the Y electrode extends is formed one by one on the Y electrode when viewed in plan view. The method of claim 8, And one slit of the Z electrode along the direction in which the Y electrode extends is formed one by one on the X electrode when viewed in plan view. A display device comprising a capacitive touch panel, The capacitive touch panel, A plurality of first electrodes extending in a first direction, A plurality of second electrodes extending in a second direction crossing the first direction; A first insulating layer insulating the first electrode and the second electrode; A plurality of third electrodes overlapping the first electrode and the second electrode in a planar view; It is composed of a second insulating layer for insulating the third electrode and the first electrode or the second electrode, The second insulating layer is a display device, characterized in that the thickness of the second insulating layer is changed by the touch. The method of claim 12, The plurality of third electrodes are each electrically floating.

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