JP2018036693A - Touch sensor and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a touch sensor that is less affected by external noise and offers good detection sensitivity.SOLUTION: A touch sensor includes a first wiring layer (first substrate 130) provided with first sensor wiring 133, and a second wiring layer (second substrate 140) provided with first ground wring 144 and disposed on a layer different from the first wiring layer. When viewed from top, at least portions of the first ground wiring runs in parallel with the first sensor wiring, and parallel portions of the first ground wiring are located at positions corresponding to spaces on the first wiring layer.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a touch sensor and a display device.

  2. Description of the Related Art In recent years, input devices that perform operations when a user touches with a finger, a pen, or the like are widely used. Such an input device is provided with a sensor (touch sensor) that detects the proximity or contact of an object to be detected. As a detection method of the touch sensor, there are various methods such as a resistance film method and a capacitance method.

  Patent Document 1 discloses a capacitive touch sensor. The plurality of electrode patterns constituting the detection unit of the touch sensor and the controller are connected by output wiring. A signal output via the output wiring is easily affected by external noise caused by finger contact or the like, and such external noise may cause malfunction of the touch sensor. For this reason, in Patent Document 1, a malfunction is caused by external noise by forming a shield layer between the output wiring and the electrode substrate.

JP 2009-169720 A

  However, the touch sensor disclosed in Patent Document 1 has an arrangement in which output wiring is sandwiched between opposing planar shield layers, and has a configuration in which a large capacitance can be generated between the output wiring and the shield layer. Therefore, in the configuration in which the shield layer is provided, the time constant of the wiring becomes large, so that the detection sensitivity of the touch sensor may be a problem.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a touch sensor in which the reduction of the influence of external noise and the securing of detection sensitivity are compatible.

  A touch sensor according to an aspect of the present invention includes a first wiring layer having a first sensor wiring and a first ground wiring, and a second sensor disposed in a layer different from the first wiring layer. A wiring layer, and when viewed from above, at least a part of the first ground wiring is parallel to the first sensor wiring, and parallel to the first sensor wiring of the first ground wiring. The portion to be arranged is arranged at a position corresponding to the space of the first wiring layer.

  A display device according to another aspect of the present invention has a first wiring layer having a first sensor wiring and a first ground wiring, and is arranged in a layer different from the first wiring layer. A second wiring layer, and when viewed from above, at least a part of the first ground wiring is parallel to the first sensor wiring, and the first sensor wiring of the first ground wiring And a display portion provided with a touch sensor arranged at a position corresponding to the space of the first wiring layer.

  ADVANTAGE OF THE INVENTION According to this invention, the touch sensor in which the influence reduction of external noise and ensuring of detection sensitivity were compatible was provided.

It is a schematic block diagram of the touch sensor which concerns on 1st Embodiment. It is a perspective view of a sensor board concerning a 1st embodiment. It is a top view of the board | substrate for a Y direction detection which concerns on 1st Embodiment. It is a top view of the substrate for X direction detection concerning a 1st embodiment. It is the perspective view which piled up the substrate for X direction detection, and the substrate for Y direction detection. FIG. 3 is a structural diagram of sensor wiring and ground wiring according to the first embodiment. FIG. 6 is a structural diagram of sensor wiring and ground wiring according to a second embodiment. FIG. 6 is a structural diagram of sensor wiring and ground wiring according to a third embodiment.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. Elements having a common function throughout the drawings are denoted by the same reference numerals, and redundant description may be omitted or simplified.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of a touch sensor according to the first embodiment. The touch sensor 10 according to the present embodiment is a capacitive sensor, and detects the proximity or contact of an object to be detected. The touch sensor 10 is used, for example, as an input device of an electronic device that is operated by a user touching with a finger, a pen, or the like. Further, by incorporating the touch sensor 10 into a display screen of a display device such as a liquid crystal display or an organic EL (electroluminescence) display, the touch sensor 10 of the present embodiment can be used as a touch panel having a function as an input / output device. A display device having a display unit provided with the touch sensor 10 according to the present embodiment can be used for electronic devices such as a display for a personal computer, a mobile phone, and a game machine.

  The touch sensor 10 includes a sensor substrate 100, a wiring substrate 200, and a control circuit 300. The sensor substrate 100 has a detection area 110 and a frame area 120. The detection area 110 is an area provided with a detection unit capable of detecting a touch (proximity or contact) by an object to be detected such as a user's finger or pen. The frame area 120 is an area that does not have a function of detecting a touch around the detection area. A wiring is provided in the frame region 120. The wiring board 200 is a board on which connection wiring for transmitting an output signal from the sensor board 100 and a driving signal for driving the touch sensor 10 is provided. For example, a flexible printed circuit board can be used for the wiring board 200. The wiring in the wiring board 200 is connected to the control circuit 300. The control circuit 300 is a circuit that performs overall control of the touch sensor 10 such as driving of the touch sensor 10 and processing of an output signal from the detection region 110.

  FIG. 2 is a perspective view of the sensor substrate 100 according to the first embodiment. The sensor substrate 100 has a structure in which a first substrate 130 and a second substrate 140 are laminated. The first substrate 130 is a substrate provided with a sensor electrode for detecting the touch position in the Y direction, and the second substrate 140 is a substrate provided with a sensor electrode for detecting the touch position in the X direction. The first substrate 130 and the second substrate 140 are insulators mainly made of glass, for example. The first substrate 130 and the second substrate 140 are bonded by an adhesive layer (not shown) such as an optical transparent adhesive or an optical transparent resin.

  A substrate or film other than the substrate shown in FIG. 2 may be further laminated. For example, when the touch sensor 10 of the present embodiment is a touch sensor for a display device such as a liquid crystal display, a substrate for ensuring a display function such as a liquid crystal panel may be further laminated. Alternatively, the function of the touch sensor 10 may be built in the liquid crystal panel by forming the touch sensor 10 according to the present embodiment using wiring on the substrate in the liquid crystal panel.

  FIG. 3A is a plan view of the first substrate 130 which is a Y-direction detection substrate. A sensor electrode 131 and a sensor pad 132 are formed in the detection region 110 of the first substrate 130. The sensor electrode 131 is a strip-shaped electrode extending in the X direction. In FIG. 3A, five sensor electrodes 131 arranged in the Y direction are illustrated as an example, but the number of sensor electrodes 131 is not limited to that illustrated. The sensor pad 132 is a pad provided at each end of the sensor electrode 131.

  In the frame region 120 of the first substrate 130, a sensor wiring 133 (first sensor wiring), a ground wiring 134 (second ground wiring), a sensor terminal 135, and a ground terminal 136 are formed. The sensor wiring 133 is a wiring connected between each sensor pad 132 and the corresponding sensor terminal 135. The sensor wiring 133 is a wiring that transmits a signal indicating a touch position in the Y direction (first direction).

  The ground wiring 134 is arranged below the detection region 110 (Y axis minus side). The sensor wiring 133 and the ground wiring 134 are formed in the same wiring layer (first wiring layer) on the first substrate 130. As shown in FIG. 3A, the ground wiring 134 has a lattice-like shape that partially intersects the X direction and the Y direction. As a result, all the ground wirings 134 composed of a plurality of wirings have the same potential. The ground wiring 134 is connected to two ground terminals 136. It is not essential that two ground terminals 136 are provided, and one or three or more ground terminals may be provided. The sensor terminal 135 is connected to the control circuit 300 via a wiring on the wiring board 200. The ground terminal 136 is connected to the ground of the wiring board 200. In FIG. 3A, the intersection of the ground wiring 134 is assumed to be conductive.

  FIG. 3B is a plan view of the second substrate 140 which is the X-direction detection substrate. In the detection region 110 of the second substrate 140, a sensor electrode 141 and a sensor pad 142 are formed. The sensor electrode 141 is a strip-shaped electrode extending in the Y direction. In FIG. 3B, eight sensor electrodes 141 are illustrated as an example, but the number of sensor electrodes 141 is not limited to that illustrated. The sensor pad 142 is a pad provided at each end of the sensor electrode 141.

  In the frame region 120 of the second substrate 140, a sensor wiring 143 (second sensor wiring), a ground wiring 144 (first ground wiring), a sensor terminal 145, and a ground terminal 146 are formed. The sensor wiring 143 is a wiring connected between each sensor pad 142 and the corresponding sensor terminal 145. The sensor wiring 143 is a wiring that transmits a signal indicating the touch position in the X direction (second direction).

  The ground wiring 144 is arranged on the right side (X axis plus side), the left side (X axis minus side), and the upper side (Y axis plus side) of the detection area 110. Thus, by arranging the ground wiring 144 so as to surround the detection region 110, the effect as a shield against external noise can be enhanced. The sensor wiring 143 and the ground wiring 144 are formed on the same wiring layer (second wiring layer) on the second substrate 140. As shown in FIG. 3B, the ground wiring 144 has a lattice-like shape that partially intersects the X direction and the Y direction. As a result, all the ground wirings 144 formed of a plurality of wirings have the same potential. The ground wiring 144 is connected to two ground terminals 136 provided at both ends of the plurality of sensor terminals 145. It is not essential that two ground terminals 146 are provided, and one or three or more ground terminals may be provided. The sensor terminal 145 is connected to the control circuit 300 via a wiring on the wiring board 200. The ground terminal 146 is connected to the ground of the wiring board 200. In FIG. 3B, the intersection of the ground wiring 144 is assumed to be conductive.

  The sensor electrodes 131 and 141, the sensor wirings 133 and 143, and the ground wirings 134 and 144 are, for example, a transparent conductive film such as indium tin oxide (ITO), a metal electrode made of copper, silver, or the like in a mesh shape with a line width of several μm. Can be configured. These electrode configurations can transmit light. Therefore, it is suitable when used as a touch sensor 10 for a touch panel of a display device.

  FIG. 3C is a perspective view seen from the + Z direction in a state where the first substrate 130 and the second substrate 140 are overlapped. In FIG. 3C, the pattern on the second substrate 140 is indicated by a solid line, and the pattern on the first substrate 130 is indicated by a broken line. In the frame region 120, the sensor wiring 133 and the ground wiring 144 are arranged so that at least a part thereof is parallel to each other in a top view. Further, when viewed from the top, a portion of the ground wiring 144 parallel to the sensor wiring 133 is disposed at a position corresponding to the space of the first wiring layer in which the sensor wiring 133 is formed.

  Similarly, the sensor wiring 143 and the ground wiring 134 are arranged so that at least a part thereof is parallel to each other in a top view. Further, in a top view, a portion of the ground wiring 134 parallel to the sensor wiring 143 is disposed at a position corresponding to the space of the second wiring layer in which the sensor wiring 143 is formed.

  FIG. 4A is an enlarged view of a region A indicated by a dashed-dotted frame in FIG. 3C. FIG. 4B is a cross-sectional view taken along the line A-A ′ of FIG. As shown in FIG. 4A and FIG. 4B, the ground wiring 144 is located at a position corresponding to the space between the plurality of sensor wirings 133, and the space between the plurality of ground wirings 144 is located. The sensor wiring 133 is located at the corresponding position. Although not shown, the configuration in which the sensor wiring 143 and the ground wiring 134 are parallel is the same. In addition, although the 1st board | substrate 130 and the 2nd board | substrate 140 can be joined by the contact bonding layer, this contact bonding layer is not illustrated in FIG.4 (b).

  Thus, in the top view, the ground wiring 144 has a positional relationship with the sensor wiring 133 interposed therebetween, and thus has an effect as a shield against external noise caused by finger contact or the like. In the present embodiment, the sensor wiring 133 and the ground wiring 144 are arranged so as not to overlap each other when viewed from above. Therefore, compared with the case where the wiring is disposed opposite to the planar shield layer as in Patent Document 1, in this embodiment, the capacitance between the sensor wiring 133 and the ground wiring 144 can be reduced. Therefore, the time constant determined by the wiring resistance and the capacitance parasitic on the wiring is reduced, and the signal delay is reduced, so that the deterioration of detection sensitivity can be reduced. Therefore, it is possible to reduce deterioration in detection sensitivity that can occur when ground wiring is provided as a shield against external noise.

  As described above, according to the present embodiment, the touch sensor 10 in which the reduction of the influence of external noise and the securing of detection sensitivity are compatible is provided. Further, by applying the touch sensor according to the present embodiment to a display unit of a display device such as a liquid crystal panel, a display device in which both the influence of external noise is reduced and the detection sensitivity is ensured is provided.

  Furthermore, in the present embodiment, since the ground wiring 144 can be disposed between the sensor wirings 133, the frame of the display device can be made narrower than when a ground wiring region is provided on the outer periphery of the sensor wiring. .

[Second Embodiment]
FIG. 5 is a cross-sectional view of the sensor substrate according to the second embodiment, and corresponds to FIG. 4B in the first embodiment. In the first embodiment, the sensor substrate 100 has two substrates, a first substrate 130 and a second substrate 140. On the other hand, in the present embodiment, the first wiring layer including the sensor wiring 133 is formed on the first main surface of one substrate 150, and the second main surface opposite to the first main surface. This is different from the first embodiment in that a second wiring layer including a ground wiring 144 is formed. Other configurations are the same as those in the first embodiment.

  In the present embodiment, the first wiring layer and the second wiring layer are formed on both surfaces of the substrate 150. Even in the case of such a relatively simplified structure, it is possible to achieve both reduction of the influence of external noise and securing of detection sensitivity, as in the first embodiment.

  In the configuration in which the sensor wiring and the ground wiring are formed across one substrate, the capacitance between the wirings tends to increase because the distance between these wirings is small. Therefore, when the arrangement in which the wiring is opposed to the planar shield layer as in Patent Document 1 is adopted, the deterioration of detection sensitivity due to the provision of the shield becomes more remarkable. Therefore, as in the present embodiment, when the ground wiring 144 is arranged at a position corresponding to the space between the plurality of sensor wirings 133 in a top view, the effect of reducing deterioration in detection sensitivity is further improved. It will be remarkable.

[Third Embodiment]
FIG. 6 is a cross-sectional view of the sensor substrate according to the third embodiment, and corresponds to FIG. 5 in the second embodiment. In the second embodiment, sensor wiring 133 and ground wiring 144 are formed on different surfaces of the substrate 150. On the other hand, in the present embodiment, the first wiring layer including the sensor wiring 133 is formed on one substrate 160, and the second wiring including the ground wiring 144 via the insulating layer 170 thereon. The point from which the layer is formed differs from 1st Embodiment. Further, an insulating layer 180 is formed thereon. The insulating layers 170 and 180 function as a passivation layer that protects the sensor wiring 133 and the ground wiring 144. About another structure, it is the same as that of 1st Embodiment or 2nd Embodiment.

  In the present embodiment, the first wiring layer and the second wiring layer are formed on both surfaces of the substrate 150. Even in the case of such a relatively simplified structure, it is possible to achieve both reduction of the influence of external noise and securing of detection sensitivity, as in the first embodiment.

  Even in the configuration in which the sensor wiring and the ground wiring are formed across the insulating layer 170 as in the present embodiment, the capacitance is likely to increase because the distance between these wirings is small. Therefore, when the arrangement in which the wiring is opposed to the planar shield layer as in Patent Document 1 is adopted, the deterioration of detection sensitivity due to the provision of the shield becomes more remarkable. Therefore, as in this embodiment, when the ground wiring 144 is arranged at a position corresponding to the space between the plurality of sensor wirings 133 in a top view, an effect of reducing deterioration in detection sensitivity can be obtained. It becomes more prominent.

[Other Embodiments]
The above-described embodiments are merely examples of some aspects to which the present invention can be applied, and do not prevent appropriate modifications and variations from being made without departing from the spirit of the present invention.

  The wiring layouts shown in FIGS. 3A, 3B, and 3C are examples, and can be appropriately changed according to the design of the touch sensor 10. For example, the sensor wiring 133 is drawn from both the left and right sides of the detection region 110, but may be drawn from only one side.

  4B, the sensor wiring 133 and the ground wiring 144 are both provided on the upper surface of the substrate. For example, the ground wiring 144 is provided on the lower surface of the second substrate 140 so that the sensor wiring 133 and the ground wiring 144 face each other. May be. In addition, the sensor wiring 133 may be provided on the lower surface of the first substrate.

130 First substrate 133 Sensor wiring 140 Second substrate 144 Ground wiring

Claims (10)

A first wiring layer having a first sensor wiring;
A second wiring layer having a first ground wiring and disposed in a layer different from the first wiring layer;
With
In a top view, at least a part of the first ground wiring is parallel to the first sensor wiring, and a portion of the first ground wiring parallel to the first sensor wiring is the first ground wiring. A touch sensor, which is arranged at a position corresponding to a space of a wiring layer. The first wiring layer has a plurality of the first sensor wirings,
2. The touch sensor according to claim 1, wherein a portion of the first ground wiring parallel to the first sensor wiring is between the plurality of first sensor wirings when viewed from above.   The touch sensor according to claim 1, wherein at least a part of the first ground wiring has a lattice shape.   4. The touch sensor according to claim 1, wherein the first ground wiring is disposed so as to surround a detection region for detecting a touch of an object to be detected. 5. The first wiring layer further includes a second ground wiring,
The second wiring layer further includes a second sensor wiring,
In a top view, at least a part of the second ground wiring is parallel to the second sensor wiring, and a portion of the second ground wiring parallel to the second sensor wiring is the second ground wiring. The touch sensor according to claim 1, wherein the touch sensor is disposed at a position corresponding to a space of the wiring layer. The first sensor wiring is a wiring for transmitting a signal indicating a touch position in a first direction,
The touch sensor according to claim 5, wherein the second sensor wiring is a wiring that transmits a signal indicating a touch position in a second direction different from the first direction. A first substrate and a second substrate stacked on each other;
The first wiring layer is formed on the first substrate;
The touch sensor according to claim 1, wherein the second wiring layer is formed on the second substrate. A first substrate having a first main surface and a second main surface;
The first wiring layer is formed on the first main surface of the first substrate;
The touch sensor according to claim 1, wherein the second wiring layer is formed on the second main surface of the first substrate. A first substrate;
The first wiring layer is formed on the first substrate;
The touch sensor according to claim 1, wherein the second wiring layer is formed on the first wiring layer with an insulating layer interposed therebetween.   A display apparatus provided with the display part in which the touch sensor of any one of Claims 1 thru | or 9 was provided.