Touch panel, display device, and electronic apparatus

A touch panel includes: first electrodes extending in a first direction; second electrodes extending in a direction intersecting the first direction; and an insulating layer insulating and separating the first electrodes from the second electrodes. The second electrodes are strip-shaped electrodes which include first island-shaped electrodes formed in the same layer as the first electrodes and relay electrodes electrically connecting two adjacent first island-shaped electrodes to each other and crossing over the first electrodes. The insulating layer has contact holes at positions corresponding to both ends of each of the relay electrodes in a longitudinal direction. A distance between two contact holes provided so as to correspond to both the ends of each of the relay electrodes in the longitudinal direction is the same as or shorter than a distance between two first island-shaped electrodes coming into contact with both the ends of each of the relay electrodes.

FIELD

The present technology relates to a touch panel which enables a position at which an object (hereinafter, referred to as the “finger or the like”) such as the finger, the hand, the arm, or a pen is touched on a detection surface of the touch panel to be detected. In addition, the present technology relates to a display device and an electronic apparatus having the touch panel.

BACKGROUND

In the related art, there have been techniques in which information is input by the touch of the finger or the like. Among them, as a technique which has particularly attracted attention, there is a display device which can input information in the same manner as in a case of pressing a normal button with the finger or the like, by touching various buttons displayed on a display with the finger or the like. This technique enables the display and the buttons to be used in common, and thus brings great merits of space saving or reduction in the number of components.

There are various types of touch panels which detect the touch of the finger or the like, and a capacitance type is generally widespread in a device in which multi-point detection is necessary such as a smart phone (for example, refer to JP-A-2010-277461). The capacitance type touch panel includes, for example, a matrix-shaped electrode pattern in the detection surface, and detects a capacitance variation of a position touched by the finger or the like.

SUMMARY

Here, the electrode pattern includes, for example, as shown inFIG. 12, a plurality of first electrodes E1extending in a predetermined direction and a plurality of second electrodes E2extending in a direction perpendicular to the first electrodes E1. The second electrodes E2include, for example, a plurality of island-shaped electrodes E3disposed in the same layer as the first electrodes E1, and relay electrodes E4electrically connecting the island-shaped electrodes E3to each other and crossing over the first electrodes E1. Here, the relay electrodes E4are formed in a further upper layer than the first electrodes E1. For this reason, in the detection surface, there is a problem in that silhouettes of the relay electrodes E4are viewed.

It is therefore desirable to provide a touch panel in which an electrode pattern is difficult to view, and a display and an electronic apparatus having the touch panel.

An embodiment of the present technology is directed to a touch panel including a plurality of first electrodes extending in a first direction; a plurality of second electrodes extending in a direction intersecting the first direction; and an insulating layer insulating and separating the first electrodes from the second electrodes. The second electrodes are strip-shaped electrodes which include a plurality of first island-shaped electrodes formed in the same layer as the first electrodes and relay electrodes electrically connecting two adjacent first island-shaped electrodes to each other and crossing over the first electrodes. The insulating layer has contact holes at positions corresponding to both ends of each of the relay electrodes in a longitudinal direction. A distance between two contact holes provided so as to correspond to both ends of each of the relay electrodes in the longitudinal direction is the same as or shorter than a distance between two first island-shaped electrodes coming into contact with both ends of each of the relay electrodes.

Another embodiment of the present technology is directed to a display device including an image generation unit that generates an image; a touch panel that is disposed on a surface of the image generation unit; and a control unit that controls the image generation unit and the touch panel.

The touch panel included in the display device according to the embodiment of the present technology has the same configuration as the above-described touch panel. An electronic apparatus according to still another embodiment of the present technology includes the above-described display device.

In the touch panel, the display device, and the electronic apparatus according to the embodiments of the present technology, two contact holes are provided so as to correspond to both ends of the relay electrode corresponding to a portion crossing over the first electrode in the second electrode. In addition, the distance between the two contact holes is the same as or shorter than the distance between two first island-shaped electrodes coming into contact with both ends of the relay electrode. Thereby, the length of the relay electrode in the longitudinal direction can be made shorter than in a case where the distance between the two contact holes is longer than the two first island-shaped electrodes, and, as a result, it is possible to reduce the area of the relay electrode.

According to the touch panel, the display device, and the electronic apparatus of the embodiments of the present technology, it is possible to reduce the area of the relay electrode, and thus a silhouette of an electrode pattern can be made difficult to view.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present technology will be described in detail with reference to the accompanying drawings. In addition, the description will be made in the following order.

1. Basic principle of touch detection type

3. Modified examples

4. Application example

1. BASIC PRINCIPLE OF TOUCH DETECTION TYPE

First, a basic principle of a touch detection type used in a display device according to the following embodiment will be described. The touch detection type is implemented by a capacitance type touch sensor.FIG. 1Aschematically shows the touch sensor.FIG. 1Bshows an equivalent circuit of the touch sensor ofFIG. 1Aand peripheral circuits connected to the touch sensor. The touch sensor includes a dielectric101, and a pair of electrodes102and103disposed opposite to each other with the dielectric101interposed therebetween, and is indicated by a capacitive element104as shown inFIG. 1Bin an equivalent circuit.

One end (the electrode102) of the capacitive element104is connected to an AC signal source105. The other end (the electrode103) of the capacitive element104is connected to a voltage detection circuit106, and is connected to a reference potential line108via a resistor107. The AC signal source105outputs AC rectangular waves Sg with a predetermined frequency (for example, approximately several kHz to several tens of kHz). The voltage detection circuit106detects a peak value of an input signal, and determines touch and non-touch of the finger on the touch sensor on the basis of the detected voltage. The reference potential line108is electrically connected to a member (for example, a ground layer of a printed circuit board or a conductive casing) which gives a potential used as a reference of a circuit operation, for example, in a device which has the touch sensor mounted therein, and has the same potential (reference potential) as the member when being connected to the member. The reference potential is, for example, a ground potential.

In the touch sensor, when the AC rectangular wave Sg (FIG. 2B) is applied to the electrode102from the AC signal source105, an output waveform (a detected signal Vdet) as shown inFIG. 2Aappears in the electrode103.

In a state (FIG. 1A) where an object such as the finger does not touch the touch sensor, as shown inFIG. 1B, a current I0corresponding to a capacitance value of the capacitive element104flows according to the charge and discharge of the capacitive element104. A potential waveform of the electrode103side of the capacitive element104at this time becomes, for example, a waveform V0as shown inFIG. 2A, which is detected by the voltage detection circuit106.

On the other hand, in a state (FIG. 3A) where an object such as the finger is touched on the touch sensor, as shown inFIG. 3B, a capacitive element109formed by the object such as the finger is added in series to the capacitive element104. In this state, currents I1and I2flow according to the charge and discharge of the capacitive elements104and109respectively. At this time, a potential waveform at the electrode103becomes a waveform V1as shown inFIG. 2A, which is detected by the voltage detection circuit106. A potential of the electrode103is a voltage-divided potential defined by values of the currents I1and I2flowing through the capacitive elements104and109. For this reason, the waveform V1has a smaller value than the waveform V0in a non-touch state. Thereafter, the detected voltage and a predetermined threshold value Vth are compared by the voltage detection circuit106, and when the detected voltage is equal to or less than the threshold value Vth, a non-touch state is determined, whereas when the detected voltage is larger than the threshold value Vth, a touch state is determined. In the above-described way, touch detection is performed. In addition, in the display device according to the following embodiment, detection types different from the above-described type may be used.

FIG. 4shows an example of the cross-sectional configuration of a display device1according to the embodiment of the present technology. The display device1is a display device with the touch sensor, and includes an image generation unit10, a capacitance type touch panel20, and a control unit30. The touch panel20is formed separately from the image generation unit10, and is disposed on a surface of the image generation unit10. The control unit30controls the image generation unit10and the touch panel20. Specifically, the control unit30drives the image generation unit10on the basis of an image signal input from an external device, further drives the touch panel20, and outputs a signal according to a detected signal of the touch panel20to the external device.

The image generation unit10generates an image on the basis of a signal input from the control unit30. The image generation unit10includes, for example, a liquid crystal display panel which varies an arrangement of liquid crystal molecules so as to transmit and modulate incident light, thereby generating an image, and a light source which illuminates the liquid crystal display panel from a back side thereof. In addition, the image generation unit10may have a configuration different from the above-described configuration, and, may include, for example, an organic EL display panel which generates an image by enabling an organic EL element to emit light.

FIG. 5shows an example of the cross-sectional configuration of the touch panel20.FIG. 6shows an example of the layout of the electrode pattern of the touch panel20. In addition,FIG. 5shows a cross-sectional configuration of a portion corresponding to the line A-A ofFIG. 6in the touch panel20.

The touch panel20inputs information when the finger or the like is touched on an image display surface (a detection surface of the touch panel20) of the display device1. The touch panel20, for example, corresponds to a specific example of the above-described capacitance type touch sensor, and detects touch and non-touch of the finger or the like on the detection surface by using an XY matrix. The touch panel20is joined to, for example, the surface of the image generation unit10via an adhesive layer or a sticky layer.

The touch panel20is obtained by joining a wire substrate21and a cover substrate22via an adhesive layer23. The wire substrate21and the cover substrate22are disposed so as to face each other with the adhesive layer23interposed therebetween. The wire substrate21is obtained by laminating, for example, a first conductive layer25, an insulating layer26, and a second conductive layer27in this order on an upper surface (a surface on the cover substrate22side) of a substrate24. The cover substrate22is provided with, for example, a light blocking layer29on a lower surface (a surface on the wire substrate21side) of a substrate28. The substrate24and the substrate28are disposed so as to face each other with the adhesive layer23interposed therebetween. The adhesive layer23is obtained by, for example, curing a UV cured resin.

The substrate24is a substrate on which the first conductive layer25, the insulating layer26, and the second conductive layer27are formed, and holds the first conductive layer25, the insulating layer26, and the second conductive layer27. The substrate24includes an insulating and translucent member, and, includes, for example, a glass substrate or an insulating and translucent resin film. The substrate28is a substrate which forms the detection surface and covers the first conductive layer25and the second conductive layer27. The substrate28also holds the light blocking layer29. The substrate28includes an insulating and translucent member, and, includes, for example, a glass substrate or an insulating and translucent resin film.

The first conductive layer25and the second conductive layer27are used to detect touch and non-touch of the finger or the like on the detection surface, and are made of a translucent and conductive material such as, for example, ITO (Indium Tin Oxide). The insulating layer26is disposed between the first conductive layer25and the second conductive layer27. The insulating layer26is used to insulate and separate first electrodes E1described later and second electrodes E2described later from each other, and is made of a translucent and insulating material such as, for example, an acryl resin. The insulating layer26has contact holes26A at predetermined positions. In addition, detailed positions of the contact holes26A will be described later in detail. The light blocking layer29is used to prevent a silhouette of a signal wire21B described later from being viewed on the image display surface, and is made of a light blocking material.

The first conductive layer25and the second conductive layer27include a sensor electrode21A which detects touch and non-touch on the detection surface and a plurality of signal wires21B which connect the sensor electrode21A and the control unit30to each other. The sensor electrode21A is disposed at a position corresponding to a portion excluding an outer edge of the upper surface in the wire substrate21. The signal wires21B are disposed at a position corresponding to the outer edge in the upper surface of the wire substrate21.

The sensor electrode21A includes a plurality of first electrodes E1extending in a predetermined direction (first direction) and a plurality of second electrodes E2extending in a direction intersecting (for example, perpendicular to) the first electrodes E1. The first electrodes E1are constituted by a portion of the first conductive layer25. In other words, the first conductive layer25includes the first electrodes E1. The first electrodes E1are formed so as to be contacted to the upper surface (the surface on the cover substrate22side) of the substrate24, and are strip-shaped electrodes including a plurality of island-shaped electrodes and connection electrodes connecting two adjacent island-shaped electrodes to each other. Here, the width of the connection electrode is smaller than the width of the island-shaped electrode.

The second electrodes E2are constituted by a portion of the first conductive layer25and the whole or a part of the second conductive layer27. In other words, the first conductive layer25includes the overall first electrodes E1and some of the second electrodes E2, and the second conductive layer27includes some of the second electrodes E2. The second electrodes E2are strip-shaped electrodes which include a plurality of island-shaped electrodes E3disposed in the same layer as the first electrodes E1and relay electrodes E4which electrically connect two adjacent island-shaped electrodes E3to each other and cross the first electrodes E1(specifically, the connection electrodes). In other words, the first conductive layer25includes the overall first electrodes E1and the respective island-shaped electrodes E3, and the second conductive layer27includes the relay electrodes E4. Here, the width of the relay electrode E4is smaller than the width of the island-shaped electrode E3. In addition, the island-shaped electrodes E3and the island-shaped electrodes of the first electrodes E1have a delta arrangement.

The relay electrodes E4have a strip shape extending in the extending direction of the second electrodes E2. In a relay electrode E4, one end thereof is connected to the island-shaped electrode E3and the other end thereof is connected to another island-shaped electrode E3, and a portion crossing over the first electrode E1is disposed in a further upper layer than the first electrode E1. The “further upper layer than the first electrode E1” indicates a layer coming into contact with the upper surface of the insulating layer26, and, specifically, indicates the second conductive layer27. Therefore, the relay electrodes E4are disposed so as to be closer to the substrate28than the island-shaped electrodes E3. The relay electrodes E4are collectively formed in manufacturing procedures, and thus are formed of a single layer. On the other hand, the island-shaped electrodes E3are formed along with the first electrodes E1in the same manufacturing procedure, and thus the island-shaped electrodes E3and the first electrodes E1are made of the same material.

Portions of both ends of the relay electrode E4in the longitudinal direction are disposed in the contact holes26A of the insulating layer26. In other words, the insulating layer26has the contact holes26A at the positions corresponding to both ends of the relay electrode E4in the longitudinal direction. Here, as shown inFIGS. 5 and 7, the contact holes26A are disposed at positions where end portions of the island-shaped electrodes E3are exposed inside the bottom surfaces of the contact holes26A and the first electrodes E1are not exposed inside the bottom surfaces of the contact holes26A. Therefore, the relay electrode E4comes into contact with the portions exposed inside the contact holes26A of the island-shaped electrodes E3and is insulated and separated from the first electrodes E1by the insulating layer26.

In addition, the end surfaces of both ends of the relay electrode E4in the longitudinal direction are preferably formed outside the contact holes26A and are preferably formed so as to come into contact with the upper surface of the insulating layer26. In a case where the end surfaces are formed inside the contact holes26A, there is a probability that the end surfaces may be formed on the island-shaped electrodes E3(that is, on the bottom surfaces of the contact holes26A) depending on manufacturing errors. At that time, if some of the island-shaped electrodes E3are not covered by the relay electrode E4but are exposed, there is a probability that the exposed portions may be etched in subsequent steps and thus the electrical connection between the island-shaped electrodes E3and the relay electrode E4may be cut. Therefore, in order to prevent this, the end surfaces of both ends of the relay electrode E4in the longitudinal direction are preferably formed so as to come into contact with the upper surface of the insulating layer26.

A distance D1between the two contact holes26A so as to correspond to both ends of the relay electrode E4in the longitudinal direction is longer than a width W1of the relay electrode of the first electrode E1, and is shorter than a distance D2between two island-shaped electrodes E3coming into contact with both ends of the relay electrode E4in the longitudinal direction. Therefore, as shown in a comparative example ofFIG. 8, the length of the relay electrode E4in the longitudinal direction is shorter and the area of the relay electrode E4is smaller than a case where the distance D1is longer than the distance D2. However, since the area of the relay electrode E4is smaller, it is difficult for a silhouette of the relay electrode E4to be viewed on the image display surface. As in the present embodiment, since the distance D1is shorter than the distance D2, a silhouette of the relay electrode E4is barely viewed on the image display surface.

On the other hand, in the comparative example ofFIG. 8, in a case where the bottom surface of the contact hole26A is certainly formed on the island-shaped electrode E3, it is necessary for a distance D3between the contact hole26A and the end surface of the island-shaped electrode E3to be a length (for example, 15 μm) in consideration of manufacturing errors. Therefore, in the comparative example ofFIG. 8, the length of the relay electrode E4in the longitudinal direction is larger than the length of the relay electrode E4according to the present embodiment by at least, for example, 30 μm, and thus there is a probability that a silhouette of the relay electrode E4may be clearly viewed.

Next, a description will be made of an example of the operation of the display device1according to the present embodiment. First, for example, the display device1is powered on, and thereby the control unit30starts an operation of the touch panel20. The control unit30first selects one or a plurality of electrodes (the first electrodes E1and the second electrodes E2) included in the sensor electrode21A, and applies an AC signal to the selected electrodes. At this time, if the finger or the like is touched on the detection surface, the control unit30detects a capacitance variation occurring in the sensor electrode21A due to the touch of the finger or the like on the detection surface as a variation in an output voltage. The control unit30derives the touch coordinates of the finger or the like on the basis of the information on the detected output voltage (or the variation in the output voltage). The control unit30outputs the derived information on the touch coordinates of the finger or the like to an external device.

Next, effects of the display device1according to the present embodiment will be described. In the present embodiment, the distance D1between the two contact holes26A so as to correspond to both ends of the relay electrode E4is shorter than the distance D2between the two island-shaped electrodes E3coming into contact with both ends of the relay electrode E4. Thereby, the length of the relay electrode E4in the longitudinal direction can be made smaller and the area of the relay electrode E4can be made smaller than in the case where the distance D1is longer than the distance D2(refer toFIG. 8). As a result, a silhouette of the electrode pattern can be made difficult to view.

In addition, it is possible to reduce the area of the relay electrode E4by optimizing positions of the contact holes26A. For this reason, it is not necessary to add new members to the electrode structure shown in the comparative example ofFIG. 8or to perform a fundamental change in the electrode structure. Therefore, it is possible to manufacture the sensor electrode21A with the same number of steps as the number of the manufacturing steps of the electrode structure shown in the comparative example ofFIG. 8.

3. MODIFIED EXAMPLES

As above, the embodiment of the present technology has been described, but the present technology is not limited to the embodiment and may be variously modified.

First Modified Example

For example, although, in the above-described embodiment, the distance D1is shorter than the distance D2, the distance D1may be the same as the distance D2as shown inFIGS. 9 and 10. However, in this case, only the upper surfaces of the island-shaped electrodes E3are exposed to the bottom surfaces of the contact holes26A.

Second Modified Example

Although, in the above-described embodiment and first modified example, the substrate24which is a substrate on which the first conductive layer25, the insulating layer26, and the second conductive layer27are formed is provided, a translucent and insulating layer may be provided instead of the substrate24. In addition, a first translucent member may be provided instead of the substrate24, and a second translucent member may be provided instead of the substrate28. At this time, a surface of the second translucent member on an opposite side to the first translucent member forms a detection surface.

4. APPLICATION EXAMPLE

Next, an application example of the display device1related to the above-described embodiment and modified examples will be described.FIG. 11is a perspective view illustrating an example of the schematic configuration of an electronic apparatus100according to the application example. The electronic apparatus100is a mobile phone, and, for example, as shown inFIG. 11, includes a main body unit111and a display body unit112which can be opened and closed with respect to the main body unit111. The main body unit111has operation buttons115and a transmission portion116. The display body unit112has a display device113and a reception portion117. The display device113performs a variety of displays regarding telephone communication on a display screen114of the display device113. The electronic apparatus100includes a control unit (not shown) for controlling an operation of the display device113. The control unit is provided as a part of a controller controlling the entire electronic apparatus100, or is provided inside the main body unit111or the display body unit112separately from the controller.

The display device113has the same configuration as the display device1according to the above-described embodiment and modified examples thereof. Thereby, in the display device1, it is difficult for a silhouette of the electrode pattern to be viewed, and thus it is possible to obtain high display quality.

In addition, electronic apparatuses which may employ the display device1according to the above-described embodiment and modified examples thereof may include not only the above-described mobile phone, but also a personal computer, a liquid crystal television, a view finder type or a monitor direct-view type video tape recorder, a car navigation apparatus, a pager, an electronic notebook, a calculator, a word processor, a workstation, a television telephone set, a POS terminal, and the like.

Further, for example, the present technology may be implemented as the following configurations.

(1) A touch panel including a plurality of first electrodes extending in a first direction; a plurality of second electrodes extending in a direction intersecting the first direction; and an insulating layer insulating and separating the first electrodes from the second electrodes, wherein the second electrodes are strip-shaped electrodes which include a plurality of first island-shaped electrodes formed in the same layer as the first electrodes and relay electrodes electrically connecting two adjacent first island-shaped electrodes to each other and crossing over the first electrodes, wherein the insulating layer has contact holes at positions corresponding to both ends of each of the relay electrodes in a longitudinal direction, and wherein a distance between two contact holes provided so as to correspond to both the ends of each of the relay electrodes in the longitudinal direction is the same as or shorter than a distance between two first island-shaped electrodes coming into contact with both the ends of each of the relay electrodes.

(2) The touch panel set forth in (1), further including a first translucent member and a second translucent member disposed so as to be opposite to each other with the first electrodes, the second electrodes, and the insulating layer interposed therebetween, wherein a surface of the second translucent member on an opposite side to the first translucent member forms a detection surface, and wherein the relay electrodes are disposed so as to be closer to the second translucent member than the first island-shaped electrodes.

(3) The touch panel set forth in (1) or (2), wherein the first electrodes are strip-shaped electrodes which include a plurality of second island-shaped electrodes and connection electrodes connecting two adjacent second island-shaped electrodes to each other.

(4) The touch panel set forth in (3), wherein the first island-shaped electrodes and the second island-shaped electrodes have a delta arrangement.

(5) A display device including an image generation unit that generates an image; a touch panel that is disposed on a surface of the image generation unit; and a control unit that controls the image generation unit and the touch panel, wherein the touch panel includes a plurality of first electrodes extending in a first direction; a plurality of second electrodes extending in a direction intersecting the first direction; and an insulating layer insulating and separating the first electrodes from the second electrodes, wherein the second electrodes are strip-shaped electrodes which include a plurality of first island-shaped electrodes formed in the same layer as the first electrodes and relay electrodes electrically connecting two adjacent first island-shaped electrodes to each other and crossing over the first electrodes, wherein the insulating layer has contact holes at positions corresponding to both ends of each of the relay electrodes in a longitudinal direction, and wherein a distance between two contact holes provided so as to correspond to both the ends of each of the relay electrodes in the longitudinal direction is the same as or shorter than a distance between two first island-shaped electrodes coming into contact with both the ends of each of the relay electrodes.

(6) An electronic apparatus including a display device, wherein the display device includes an image generation unit that generates an image; a touch panel that is disposed on a surface of the image generation unit; and a control unit that controls the image generation unit and the touch panel, wherein the touch panel includes a plurality of first electrodes extending in a first direction; a plurality of second electrodes extending in a direction intersecting the first direction; and an insulating layer insulating and separating the first electrodes from the second electrodes, wherein the second electrodes are strip-shaped electrodes which include a plurality of first island-shaped electrodes formed in the same layer as the first electrodes and relay electrodes electrically connecting two adjacent first island-shaped electrodes to each other and crossing over the first electrodes, wherein the insulating layer has contact holes at positions corresponding to both ends of each of the relay electrodes in a longitudinal direction, and wherein a distance between two contact holes provided so as to correspond to both the ends of each of the relay electrodes in the longitudinal direction is the same as or shorter than a distance between two first island-shaped electrodes coming into contact with both the ends of each of the relay electrodes.

The present disclosure contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2012-012396 filed in the Japan Patent Office on Jan. 24, 2012, the entire contents of which are hereby incorporated by reference.