Touch-panel display device

Abstract

To provide a touch-panel display device which can achieve high display contrast, an easy structure, and low cost and which is useful also as an in-cell touch panel.SOLUTION: A touch-panel display device includes: a first substrate having switching elements and a pixel electrode; a second substrate having a conductive layer; a display layer sandwiched between the first and second substrates; and switch wires capable of switching between a first state in which the conductive layer functions as a sensor electrode for detecting a change of capacitance due to touch input and a second state in which the conductive layer functions as a counter electrode for generating a display drive voltage between the pixel electrode and itself.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The following disclosure relates to a touch panel display device.

Background Art

[0002] In recent years, touch panel display devices equipped with touch sensors that detect contact with the screen such as fingers and touch pens have been put into practical use. Touch panel display devices are used, for example, as smartphones, tablet terminals, smartwatches, head-mounted displays, personal computers, automotive instrument panels, copiers, ATMs (Automatic Teller Machines), and the like.

[0003] Regarding conventional touch panel display devices, for example, Patent Document 1 discloses a touch panel function-equipped non-volatile display device in which a touch panel base material also serves as a transparent substrate of a display unit, and a transparent electrode formed on this touch panel base material serves as both a conductive film for position detection and a common electrode for display driving. Patent Document 2 also discloses a touch panel integrated electronic paper in which electronic ink is provided between an upper substrate including an upper electrode and a sensing electrode and a lower substrate including a lower electrode.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] As touch sensor methods, various methods such as the resistive film type, capacitive type, and optical type are known. Touch panel type display devices (also referred to as touch panels) include a method of externally attaching a touch sensor (external type) and a method of incorporating a touch sensor (built-in type). The built-in touch panel is advantageous in terms of having a narrower bezel, being thinner, and being lighter than the external touch panel, and also has the advantage of increasing the light transmittance.

[0006] The built-in touch panel includes an on-cell type and an in-cell type. A cell means a display panel including an active matrix substrate typified by a thin film transistor (TFT) substrate, a counter substrate arranged to face the substrate, and a display layer held between these substrates. Usually, in the in-cell type, a layer responsible for the touch sensor function is arranged in the display panel, and in the on-cell type, the layer responsible for the touch sensor function is arranged between the display panel and a polarizing plate provided on the observation surface side of the display panel. Among these, the in-cell type can, in principle, realize the thinnest and lightest touch panel. However, the in-cell type touch panel has not been realized so far.

[0007] FIG. 13 is a schematic cross-sectional view showing an example of a conventional touch panel display device. The touch panel display device 1R shown in FIG. 13 includes, in order from the back side toward the observation surface side, a transparent substrate 11, a layer 12 including a thin film transistor (TFT) and a pixel electrode, a display layer 30 (for example, an electrophoretic display layer), a counter electrode 22R, a transparent substrate 21, a touch sensor TS, and a cover layer 40 (for example, a cover glass or a cover film). Adhesive layers such as OCA are provided on both sides of the touch sensor TS. In the display device 1R, since the touch sensor TS is bonded to the transparent substrate 21, the thickness of the display device 1R inevitably increases, which is a constraint on the housing design. Also, the reflection contrast decreases by the thickness of the touch sensor TS (see (f) in FIG. 13). In the display device 1R, due to the touch sensor TS being laminated over the entire display screen, the lamination interface is large, which causes a decrease in the reflection contrast of the display device 1R. Also, even when attempting to in-cell the display device 1R, it is difficult to in-cell the display device 1 because the counter electrode 22R blocks the signals of the in-cell touch sensor.

[0008] The present invention has been made in view of the above situation, and an object thereof is to provide a touch panel display device having high display contrast, a simple structure, cost reduction, and being useful as an in-cell type touch panel.

Means for Solving the Problems

[0009] (1) An embodiment of the present invention includes a first substrate having a switching element and a pixel electrode, a second substrate having a conductive layer, a display layer sandwiched between the first substrate and the second substrate, and a switch wiring capable of switching between a first state in which the conductive layer functions as a sensor electrode that detects a change in capacitance due to a touch input and a second state in which the conductive layer functions as a counter electrode that generates a display drive voltage between the conductive layer and the pixel electrode. A touch panel display device.

[0010] (2) Further, in an embodiment of the present invention, in addition to the configuration of (1) above, the display layer includes a charged member, and the display is switched by the movement or rotation of the charged member when the display drive voltage is generated. A touch panel type display device.

[0011] (3) Further, in an embodiment of the present invention, in addition to the configuration of (1) or (2) above, the display layer is an electrophoretic type. A touch panel type display device.

[0012] (4) Further, in an embodiment of the present invention, in addition to the configuration of (1), (2) or (3) above, the switching between the first state and the second state is performed in a time division manner. A touch panel type display device.

[0013] (5) Further, in an embodiment of the present invention, in addition to the configuration of (1), (2), (3) or (4) above, a control unit is further provided, the conductive layer is composed of a plurality of conductive layers, and the control unit is based on the change in the capacitance of each conductive layer in the first state. A touch panel type display device that determines the position of a touch input.

[0014] (6) Further, in an embodiment of the present invention, in addition to the configuration of (5) above, the control unit, in the first state, after detecting the change in the capacitance of each conductive layer in a time division manner, operates the switch wiring to switch to the second state. A touch panel type display device.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide a touch panel type display device that has a high display contrast, a simple structure, can achieve cost reduction, and is also useful as an in-cell type touch panel.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0017] (Definition of Terms) In this specification, the observation surface side means the side closer to the screen (display surface) of the display device, and the back side means the side farther from the screen (display surface) of the display device.

[0018] The state of no voltage applied means a state where the voltage applied to the display layer is less than the threshold voltage (including no voltage applied). The state of voltage applied means a state where the voltage applied to the display layer is equal to or greater than the threshold voltage. In this specification, the state of no voltage applied is also referred to as the time of no voltage applied, and the state of voltage applied is also referred to as the time of voltage applied.

[0019] Contact (also referred to as touch) includes the meaning of "proximity" (getting closer) in addition to the ordinary meaning of "contact" (getting close and touching).

[0020] Hereinafter, a touch panel type display device (also simply referred to as a "display device") according to an embodiment of the present invention will be described. The present invention is not limited to the content described in the following embodiments, and design changes can be appropriately made within the scope that satisfies the configuration of the present invention. Note that only the main parts are shown in the drawings.

[0021] (Embodiment 1) FIG. 1 is a schematic cross-sectional view of a display device 1 as an example of this embodiment. FIG. 2 is a more simplified schematic cross-sectional view of FIG. 1, omitting parts other than the main parts. On the paper surface, the upper side is the observation surface side of the display device 1 and the side where the touch input body X is located, and the lower side is the back side of the display device 1. As shown in FIG. 1, the display device 1 includes, in order from the back side, a first substrate 10, a display layer 30, and a second substrate 20. The display device 1 further includes switch wirings SW1 and SW2.

[0022] (First substrate 10) The first substrate 10 has a switching element and a pixel electrode. In FIGS. 1, 2, etc., for the sake of convenience, the layer including the switching element and the pixel electrode is labeled with reference numeral 12. Therefore, both the switching element (such as a TFT) and the pixel electrode are labeled 12. The first substrate 10 preferably has a support substrate 11, and on the support substrate 11, there are a plurality of source wirings (also referred to as signal lines), a plurality of gate wirings (also referred to as scanning lines), a plurality of switching elements 12, and pixel electrodes 12. An insulating layer (also referred to as an insulating film) is provided between each layer as necessary.

[0023] The support substrate 11 is preferably transparent and insulating. Examples of the support substrate 11 include a glass substrate and a plastic substrate.

[0024] The plurality of source wirings are arranged substantially parallel to each other along the column direction. The plurality of gate wirings are arranged substantially parallel to each other along the row direction so as to intersect each source wiring substantially perpendicularly. A substantially rectangular region surrounded by two adjacent gate wirings and two adjacent source wirings becomes one pixel. In each pixel, a switching element 12 is arranged at the intersection of the source wiring and the gate wiring. The switching element 12 is, for example, a thin film transistor (TFT: Thin Film Transistor). In an in-cell type touch panel, an In-Ga-Zn-O based semiconductor is particularly preferably used as the TFT.

[0025] The pixel electrodes 12 are arranged in each of the plurality of pixels. The pixel electrode 12 is preferably a transparent electrode. The transparent electrode is preferably formed using a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO), or an alloy thereof.

[0026] (Second substrate 20) The second substrate 20 is disposed opposite to the first substrate 10 with the display layer 30 therebetween, and has a conductive layer 22. More specifically, the second substrate 20 preferably has a support substrate 21, and it is preferable that the conductive layer 22 is provided on the support substrate 21. An insulating layer (also referred to as an insulating film) may be provided between each layer and the like as necessary.

[0027] The support substrate 21 is preferably transparent and insulating. Examples of the support substrate 21 include a glass substrate and a plastic substrate. The support substrate 21 is, for example, a film-like or sheet-like base material.

[0028] The conductive layer 22 is disposed so as to face a plurality of pixel electrodes 12 arranged for each pixel of the first substrate 10. In the present embodiment, the conductive layer 22 is formed in a planar (solid) shape on the support substrate 21. That is, the conductive layer 22 is a so-called solid electrode. The conductive layer 22 is preferably a transparent conductive layer. The transparent conductive layer is preferably formed using a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO), or an alloy thereof. The conductive layer 22 may also be formed of a conductive polymer.

[0029] As will be described later, the conductive layer 22 functions as a sensor electrode in the first state and as a counter electrode in the second state by switching the switch wiring SW. The conductive layer 22 does not function as a sensor electrode and a counter electrode simultaneously.

[0030] The sensor electrode is an electrode that detects changes in capacitance due to touch input. The sensor electrode only needs to be an electrode that can detect at least whether a touch input object has contacted (including approached) or separated from the sensor electrode (i.e., the conductive layer 22). The arrow (a) in FIG. 2 indicates the touch or non-touch of the touch input object X. The detection method of the sensor electrode is preferably a self-capacitance drive method. When the touch input object X contacts the outermost layer (e.g., the cover layer described later) on the observation surface side of the display device 1, a part of the charge flows to the touch input object X, so the capacitance formed between the conductive layer 22 and the sensor electrode changes (see FIGS. 4A and 4B). The sensor electrode detects this change in capacitance in a capacitance detector 60 connected to the sensor electrode, and the capacitance detector 60 transmits (outputs) the detection information to, for example, the control unit 50 or the like.

[0031] FIGS. 3A and 3B are diagrams conceptually showing the voltage when there is no touch by the touch input object X. FIGS. 4A and 4B are diagrams conceptually showing the voltage when there is a touch by the touch input object X. When there is a touch by the touch input object, the capacitance increases by Ct (see FIG. 4B).

[0032] In FIGS. 1, 2, 3A, and 4A, the mode in which the touch input object X is a user's finger is illustrated, but the touch input object X is not limited to only a finger, and may be, for example, a touch pen (including a stylus pen) or a glove. Note that (b) in FIG. 2 means the display size.

[0033] As described above, in this embodiment, the conductive layer 22 is a so-called solid electrode. Therefore, in the first state, the conductive layer 22 as the sensor electrode can determine whether it has been touched or not touched at any location within its plane.

[0034] The counter electrode is an electrode that faces the pixel electrode 12 of the first substrate 10. In the second state, the conductive layer 22 becomes the reference potential (Vcom), and a display drive voltage V for driving the display layer 30 is generated between the conductive layer 22 and the pixel electrode 12.

[0035] The second substrate 20 may also have a plurality of columnar spacers (not shown). The first substrate 10 may also have a plurality of columnar spacers.

[0036] (Display layer 30) The display layer 30 is disposed between the first substrate 10 and the second substrate 20 (see FIGS. 1 and 2). The first substrate 10 or the second substrate 20 and the display layer 30 may be in direct contact, or one or more other layers may be disposed between the first substrate 10 or the second substrate 20 and the display layer 30.

[0037] The display layer 30 preferably includes a charged member 31, and more preferably is a layer in which the display is switched by the movement or rotation of the charged member 31 when the display driving voltage V is generated. The charged member 31 is, for example, charged particles or cholesteric liquid crystal. Specific examples of the display layer 30 include an electrophoretic display layer, a liquid crystal display layer, an organic EL display layer, etc., and among them, an electrophoretic display layer is preferable, and a microcapsule type electrophoretic display layer that moves charged particles 31 in microcapsules is more preferable. When the display layer 30 is a microcapsule type electrophoretic display layer, the charged particles 31 and the liquid dispersion medium can be held in the microcapsules.

[0038] For example, when the display layer 30 is a layer in which the display is switched by the rotation of the charged member 31 when the display driving voltage V is generated, the display layer 30 is preferably a layer that absorbs, scatters, or reflects light to display an image by the charged particles 31 coated with a black substance on half of the particle surface and a white substance on the remaining half rotating along a specific axis by the voltage applied to the display layer 30.

[0039] For example, when the display layer 30 is a layer in which the display is switched by the movement of the charged member 31 when the display drive voltage V is generated, the display layer 30 is preferably a layer that displays an image by, for example, applying a voltage to the display layer 30 to electrically move black charged particles 31 and white charged particles 31 that are dispersed in a liquid dispersion medium and charged with different charges. A preferred example of such a display layer 30 is the microcapsule-type electrophoretic display layer described above. In the second state, the degree of distribution of the charged particles 31 can be changed by controlling the electric field between the conductive layer 22 and the pixel electrode 12, such as by adjusting the magnitude and application time of the voltage applied to the pixel electrode 12. As a result, the gradation of each pixel is changed (i.e., the display is rewritten). The rewritten display state can be maintained without power supply.

[0040] (Switch wiring SW) The display device 1 includes a switch wiring SW that can be switched between a first state in which the conductive layer 22 functions as a sensor electrode for detecting a change in capacitance due to a touch input and a second state in which the conductive layer 22 functions as a counter electrode for generating a display drive voltage between the conductive layer 22 and the pixel electrode. The display device 1 may include a plurality of switch wirings SW.

[0041] The switch wiring SW preferably includes a switch wiring SW1 connected to the conductive layer 22 and a switch wiring SW2 connected to the pixel electrode 12 (see FIGS. 1 and 2). The switch wiring SW1 connected to the conductive layer 22 is configured to be electrically connected to the capacitance detector 60 side, and the switch wiring SW2 connected to the pixel electrode 12 is configured to be electrically connected to the display drive voltage V side (see FIGS. 1 and 2).

[0042] When switching (i.e., rewriting) the display of the display device 1, it is necessary to apply a voltage (i.e., a display driving voltage) between the conductive layer 22 and the pixel electrode 12. Therefore, the switch wiring SW1 can be switched and connected, for example, at time intervals, to the capacitance detector 60 side and the display driving voltage V side. Switching is also referred to as switching over. When the switch wiring SW1 connected to the conductive layer 22 is switched to the capacitance detector 60 side, a first state occurs. When the switch wiring SW2 connected to the pixel electrode 12 is switched to the display driving voltage V side, a second state occurs.

[0043] In the first state, rather than connecting the pixel electrode 12 to a fixed potential, it is preferable to open the switch wiring SW2 connected to the pixel electrode 12 to make the pixel electrode 12 in a floating state. Thereby, the load on the conductive layer 22 as the sensor electrode is reduced. That is, the switch wiring SW2 is configured to be in an open state when the switch wiring SW1 is switched to the capacitance detector 60 side, and to be switched to the display driving voltage V side when the switch wiring SW1 is switched to the display driving voltage V side. In the second state, a display driving voltage is generated between the pixel electrode 12 with the conductive layer 22 as the reference potential (Vcom).

[0044] When the switch wiring SW is operated, the switching between the first state and the second state is performed. Since the first state corresponds to a so-called touch waiting state, the display device 1 is normally in the first state. When a touch is detected in this first state, the display device 1 transitions from the first state to the second state. That is, for example, when the sensor electrode detects this change in capacitance in the capacitance detector 60 connected to the sensor electrode, based on this detection information, the control unit 50 operates the switch wiring SW to switch the display device 1 from the first state to the second state. Touch detection is not performed in the second state. When the display switching (i.e., display rewriting) is completed in the second state, the display device 1 also transitions to the first state. That is, for example, when the control unit 50 determines that the display rewriting has ended in the second state, the control unit 50 operates the switch wiring SW to switch the display device 1 from the second state to the first state. The time required for display rewriting in the second state varies depending on whether it is black-and-white or color display, the performance of switching elements such as TFTs, etc., but is, for example, about 1 to 20 seconds.

[0045] In this embodiment, it is preferable that the switching between the first state and the second state is performed in a time-division manner. Also, the switching between the first state and the second state may be performed based on an instruction from the control unit 50.

[0046] FIG. 5 is a timing chart conceptually showing a mode in which the switching between the first state and the second state is performed in a time-division manner in the display device 1 shown in FIG. 1. In FIG. 5, the horizontal axis represents time, and the vertical axis represents capacitance in the upper chart (refer to "SW1") and applied voltage in the lower chart (refer to "SW2"). When the switch wiring SW1 is connected to the capacitance detector 60 side, the capacitance detector 60 continuously or intermittently detects the capacitance (refer to (x) in FIG. 5). When the touch input body X contacts the display device 1 in this state (refer to (y) in FIG. 5), the capacitance changes. Accordingly, the switch wiring SW1 is switched to the display drive voltage V side, and the display is switched (refer to (z) in FIG. 5). ON means a voltage application state, and OFF means a non-voltage application state (in both cases, the voltage is the display drive voltage). After a certain period of time has elapsed (i.e., for example, after the display rewriting has ended), the switch wiring SW1 is switched to the capacitance detector 60 side. Such operations are repeated a plurality of times.

[0047] (Cover layer 40) The display device 1 may include a cover layer 40 on the observation surface side of the second substrate 20 (refer to FIG. 1). The cover layer 40 may be a flattening layer for flattening the outermost surface on the observation surface side of the display device 1, or may be an optical function layer provided with an optical function. Examples of the optical function layer include a polarizing layer, an antireflection layer, a hard layer, an ultraviolet blocking layer, a moisture-proof layer, an antiglare layer, and the like.

[0048] The cover layer 40 is preferably transparent, and more preferably a layer formed of, for example, a transparent resin. Depending on the materials for forming the electrodes and each layer, etc., the white display of the display device 1 may have a yellowish tint. In that case, chromaticity adjustment (i.e., blue shift) may be performed by forming the cover layer 40 with a blue resist, so that the chromaticity of the white display approaches, for example, the chromaticity of the D65 light source. The D65 light source is the CIE standard light source D65.

[0049] (Adhesive layer ad) In the display device 1, each layer may be attached using an adhesive. A layer composed of an adhesive is referred to as an adhesive layer ad. For example, the cover layer 40 may be disposed on the second substrate 20 via the adhesive layer ad (see FIG. 1). As the adhesive, for example, an optically clear adhesive (OCA) is preferably used.

[0050] (Control unit 50) The display device 1 preferably includes a control unit 50 (see FIG. 6). The control unit 50 is provided, for example, in a non-display area of the display device 1. The non-display area is located, for example, around the display area and is also referred to as a peripheral area or a bezel area. Note that FIG. 6 is a block diagram showing an example of the configuration of the display device 1 of the present embodiment.

[0051] The control unit 50 preferably includes a switching control unit for operating the switch wiring SW1 to switch between a first state and a second state. For example, the switching control unit executes switching between the first state and the second state in a time-division manner. The switching control unit may execute switching between the first state and the second state based on, for example, an instruction from a user. More specifically, as described above, the switching control unit executes switching from the first state to the second state when a touch is detected, and preferably executes switching from the second state to the first state when the display rewrite is completed in the second state.

[0052] The display device 1 also includes, in addition to the members described above, external circuits such as TCP (Tape Carrier Package) and PCB (Printed Wiring Board); optical films such as a viewing angle expansion film and a brightness enhancement film; a bezel (frame); and the like. These are not particularly limited, and those commonly used in the field of display devices can be used, so the description is omitted.

[0053] Conventionally, for example, after forming a display with layers from a transparent substrate 11 to a transparent substrate 21 shown in FIG. 13, a touch panel type display device 1R was manufactured by retrofitting a touch sensor TS. However, in the display device 1 of the present embodiment, the conductive layer 22 can have the functions of both a sensor electrode and a counter electrode (display switching electrode). That is, as shown in FIG. 7, the display device 1 has a single conductive layer 22 in cross-sectional view, and this single layer can be used for both the display switching electrode and the sensor electrode. Therefore, the display device 1 can simplify the structure and contribute to thinning compared to the conventional display device 1R. FIG. 7 is a cross-sectional schematic view of the display device 1 of an example of the present embodiment. Arrow (c) means the direction of electrode transfer, and arrow (d) means the direction of electrode transfer common to the sensor electrode and the display switching electrode. FPC means a flexible substrate.

[0054] The display device 1 of the present embodiment can also reduce the number of electrode layers compared to, for example, the touch panel integrated type electronic paper described in Patent Document 2. By reducing the number of electrode layers in the display device 1, improvement in display contrast, simplification of the structure, and cost reduction can be achieved. The display device 1 of the present embodiment can also set the pixel electrode 12 in a floating state when the conductive layer 22 functions as a sensor electrode. Therefore, the display device 1 can reduce the load on the sensor electrode compared to, for example, the non-volatile display device with a touch panel function described in Patent Document 1.

[0055] The display device 1 of the present embodiment is suitably used for various applications, and is suitable as an external touch panel or an in-built touch panel. Among these, the display device 1 is useful as an in-built touch panel, more useful as an in-cell touch panel, and particularly useful as an in-cell touch panel capable of reflective mode display. The display device 1 is also extremely useful as electronic paper.

[0056] As described above, the display device 1 of the present embodiment is useful as an in-cell type touch panel. For example, it can eliminate the need for a bezel wiring area that is necessary in an external touch panel. Therefore, the display device 1 can achieve a narrow bezel and contribute to thinning and weight reduction. Also, since the touch function and the display function of the display device 1 are driven in a time-division manner, no killer pattern occurs, and tuning (adjustment) of the touch signal is easy. Further, the display device 1 has sufficiently little loss of reflected light, provides a more natural pen writing, and gives a display without a sense of discomfort. Moreover, the display device 1 can achieve a total cost reduction from the user's perspective compared to an external touch panel. In addition, the display device 1 can combine input by a finger and pen input by an electromagnetic induction method (EMR) to realize highly accurate pen writing.

[0057] (Embodiment 2) In this embodiment, features specific to this embodiment will be mainly described, and descriptions of content overlapping with Embodiment 1 will be omitted. In Embodiment 1, an aspect having one conductive layer was described, but the display device 1 of this embodiment is mainly different from the liquid crystal display device of Embodiment 1 in that it includes a plurality of conductive layers in the display area. The display device 1 of this embodiment is substantially the same as the display device 1 of Embodiment 1 except for the above point.

[0058] FIG. 8 is a schematic cross-sectional view of a display device 1 according to an example of this embodiment. On the paper surface, the upper side is the observation surface side of the display device 1 and the side where the touch input body X is located, and the lower side is the back side of the display device 1. As shown in FIG. 8, the display device 1 includes, in order from the back side, a first substrate 10, a display layer 30, and a second substrate 20. The display device 1 further includes switch wirings SW1, SW2, and SW3.

[0059] In Embodiment 1, the conductive layer 22, which was single, is divided into two within the display area in this embodiment, and the circuit is configured such that each of them is connected to the capacitance detector 60. Of the two conductive layers 22, one conductive layer 22 is referred to as the first conductive layer 221, and the other conductive layer 22 is referred to as the second conductive layer 222. In a cross-sectional view, it can be said that the display device 1 has a single layer of the first conductive layer 221 (or a single layer of the second conductive layer 222) (see FIG. 8), and this single layer can be used for both the display switching electrode and the sensor electrode.

[0060] A switch wiring SW1 is connected to the first conductive layer 221, and a switch wiring SW2 is connected to the second conductive layer 222. A switch wiring SW3 is connected to the pixel electrode 12. The switch wiring SW1 and the switch wiring SW2 are each configured to be electrically connected to the capacitance detector 60 side, and the switch wiring SW3 is configured to be electrically connected to the display drive voltage V side (see FIG. 8).

[0061] The switch wiring SW1 and the switch wiring SW2 are each connected to the capacitance detector 60 side and the display drive voltage V side, for example, by switching at time intervals. The switch wiring SW1 and the switch wiring SW2 are configured such that when the switch wiring SW1 switches to the capacitance detector 60 side, the switch wiring SW2 also switches to the capacitance detector 60 side, and when the switch wiring SW1 switches to the display drive voltage V side, the switch wiring SW2 also switches to the display drive voltage V side. A first state occurs when the switch wiring SW1 and the switch wiring SW2 switch to the capacitance detector 60 side, and a second state occurs when the switch wiring SW3 switches to the display drive voltage V side.

[0062] Also in the display device 1 of the present embodiment, in the first state, instead of connecting the pixel electrode 12 to a fixed potential, it is preferable to open the switch wiring SW3 connected to the pixel electrode 12 to make the pixel electrode 12 in a floating state. Thereby, the load of the conductive layer 22 as the sensor electrode is reduced. That is, the switch wiring SW3 is in an open state when the switch wirings SW1 and SW2 are switched to the capacitance detector 60 side, and when the switch wirings SW1 and SW2 are switched to the display drive voltage V side, it is also preferable that the switch wiring SW3 is switched to the display drive voltage V side. In the second state, with the first conductive layer 221 and the second conductive layer 222 as the reference potential (Vcom) respectively, a display drive voltage is generated between the pixel electrode 12 and them.

[0063] FIG. 9 is a timing chart conceptually showing a mode in which the switching between the first state and the second state is performed in a time-division manner in the display device 1 shown in FIG. 8. In FIG. 9, the horizontal axis represents time, and the vertical axis represents capacitance in the upper chart (refer to "SW1&SW2") and applied voltage in the lower chart (refer to "SW3"). When the switch wirings SW1 and SW2 are respectively connected to the capacitance detector 60 side, the capacitance detector 60 continuously or intermittently detects the capacitance (refer to (x) in FIG. 9). When the touch input body X contacts the display device 1 in this state (refer to (y) in FIG. 9), the capacitance changes. Along with this, the switch wiring SW1 is reconnected to the display drive voltage V side, and the display is switched (refer to (z) in FIG. 9). ON means a voltage application state, and OFF means a non-voltage application state (both voltages are display drive voltages). After a certain period of time has passed (that is, for example, after the display rewriting has ended), the switch wirings SW1 and SW2 are reconnected to the capacitance detector 60 side. Such operations are repeated a plurality of times.

[0064] The display device 1 of the present embodiment also preferably includes a control unit 50 (see FIG. 6). FIG. 6 is also a block diagram showing an example of the configuration of the display device 1 of the present embodiment.

[0065] The control unit 50 preferably determines the position of the touch input based on the change in the capacitance of each conductive layer 22 (for example, the first conductive layer 221 and the second conductive layer 222) in the first state. That is, the display device 1 of the present embodiment further includes a control unit 50, the conductive layer 22 is composed of a plurality of conductive layers 22 (for example, the first conductive layer 221 and the second conductive layer 222), and it is preferable that the control unit 50 determines the position of the touch input based on the change in the capacitance of each conductive layer 22 in the first state. The position of the touch input is the position of the conductive layer located at the portion where the touch input body X contacts among the plurality of conductive layers 22. Among the control unit 50, the part that determines the position of the touch input based on the change in the capacitance of each conductive layer 22 in the first state is also referred to as a position determination unit. The control unit 50 may include a position determination unit and a switching control unit.

[0066] For example, in the first state, when the touch input body X contacts the display device 1, this contact (i.e., the change in capacitance) is detected by the capacitance detector 60. The capacitance detector 60 outputs this detection information to the control unit 50. The control unit 50 acquires this detection information and, according to the capacitance change (or the absence of capacitance change) of each conductive layer 22, for example, by software processing, determines how the touch input body has moved (i.e., for example, whether the touch input body X has contacted the portion where the first conductive layer 221 is located or the portion where the second conductive layer 222 is located). This determination is also referred to as gesture determination. Note that the arrow (e) in FIG. 8 conceptually shows the movement of the touch input body X.

[0067] Also, in the first state, after the control unit 50 detects the change in the capacitance of each conductive layer 22 in a time-division manner, it is preferable to operate the switch wiring SW to switch to the second state. For example, when the display device 1 shown in FIG. 8 is in the first state, the control unit 50 preferably detects the change in the capacitance of the first conductive layer 221 and the second conductive layer 222 in a time-division manner in the first state, and then switches the switch wiring SW1 and the switch wiring SW2 to the display driving voltage V side.

[0068] The display device 1 of the present embodiment can also simplify the structure and contribute to thinning as compared with the conventional display device 1R, similar to the display device 1 of the first embodiment. Further, the display device 1 of the present embodiment can reduce the number of electrode layers, improve display contrast, simplify the structure, and reduce costs as compared with, for example, the touch panel integrated electronic paper described in Patent Document 2. The display device 1 of the present embodiment can also reduce the load on the sensor electrode as compared with, for example, the non-volatile display device with a touch panel function described in Patent Document 1, and can also use the conductive layer 22 dividedly within the display area, which could not be achieved with the display device described in Patent Document 1.

[0069] (Modification Example of Embodiment 2) In Embodiment 2, among the modes in which the display device 1 includes a plurality of conductive layers 22, the mode in which the number of the conductive layers 22 is particularly two was mainly described, but the number of the conductive layers 22 is not limited to two. The number of the conductive layers 22 can be appropriately set in consideration of, for example, the size of the display and the gesture operation.

[0070] For example, in this example, an example of the display device 1 when the conductive layer, which was one in Embodiment 1, is divided into eight within the display area will be described. FIG. 1 is also a cross-sectional schematic view of an example of the display device 1 of the present embodiment. FIG. 10 is a more simplified cross-sectional schematic view of FIG. 1, omitting parts other than the main parts. FIG. 11 is a schematic view of the conductive layer 22 in FIG. 10 in a plan view, and reference numerals 221 to 228 are attached to each of the eight divided conductive layers 22.

[0071] In the display device 1 of this example, a circuit is configured such that the eight conductive layers 221 to 228 are each connected to the capacitance detector 60. Each of the eight conductive layers 221 to 228 is connected to each of the switch wirings SW1 to SW8. A switch wiring SW9 is connected to the pixel electrode 12. The switch wirings SW1 to SW8 are each configured to be electrically connected to the capacitance detector 60 side, and the switch wiring SW9 is configured to be electrically connected to the display drive voltage V side (see FIG. 10).

[0072] Switch wirings SW1 to SW8 can be switched and connected to the capacitance detector 60 side and the display drive voltage V side, for example, at time intervals. Switch wirings SW1 to SW8 are configured to switch to the capacitance detector 60 side simultaneously and are also configured to switch to the display drive voltage V side simultaneously. When switch wirings SW1 to SW8 switch to the capacitance detector 60 side, a first state occurs, and when switch wiring SW9 switches to the display drive voltage V side, a second state occurs.

[0073] Also in the display device 1 of the present embodiment, in the first state, rather than connecting the pixel electrode 12 to a fixed potential, it is preferable to open the switch wiring SW9 connected to the pixel electrode 12 to make the pixel electrode 12 in a floating state. Thereby, the load on the conductive layer 22 as the sensor electrode is reduced. That is, the switch wiring SW9 is in an open state when the switch wirings SW1 to SW8 switch to the capacitance detector 60 side, and it is preferable that the switch wiring SW9 also switches to the display drive voltage V side when the switch wirings SW1 to SW8 switch to the display drive voltage V side. In the second state, with the conductive layers 221 to 228 as the reference potential (Vcom) respectively, a display drive voltage is generated between the pixel electrode 12.

[0074] FIG. 12 is a timing chart conceptually showing a mode in which the switching between the first state and the second state is performed in a time-division manner in the display device 1 shown in FIG. 10. In FIG. 12, the horizontal axis represents time, and the vertical axis represents capacitance in the upper chart (see "SW1 to SW8"), and represents the applied voltage in the lower chart (see "SW9"). When the switch wirings SW1 to SW8 are each connected to the capacitance detector 60 side, the capacitance detector 60 continuously or intermittently detects capacitance (see (x) in FIG. 12). When the touch input body X contacts the display device 1 in this state (see (y) in FIG. 12), the capacitance changes. Accordingly, the switch wiring SW1 is reconnected to the display drive voltage V side, and the display is switched (see (z) in FIG. 12). ON means a voltage application state, and OFF means a non-voltage application state (in both cases, the voltage is the display drive voltage). After a certain period of time has elapsed (i.e., for example, after the display rewriting has ended), the switch wirings SW1 to SW8 are reconnected to the capacitance detector 60 side. Such operations are repeated a plurality of times.

[0075] As described above, the embodiments of the present invention have been described. However, all of the individual matters described can be applied to the entire present invention. In addition, the above-described aspects may be appropriately combined within a range not departing from the gist of the present invention.

Description of Reference Numerals

[0076] 1: Touch panel display device 1R: Conventional touch panel display device 10, 20: Substrate 11, 21: Support substrate (e.g., transparent substrate) 12: Layer including switching element and pixel electrode 22, 221, 222, 223, 224, 225, 226, 227, 228: Conductive layer 22R: Counter electrode 30: Display layer 31: Charging member (e.g., charged particles) 40: Cover layer 50: Control unit 60: Capacity detector ad: Adhesive layer pc: Parasitic capacitance ac: Integrator SW, SW1~SW9: Switch wiring TS: Touch sensor V: Display drive voltage X: Touch input body

Claims

1. A first substrate having a switching element and a pixel electrode, A second substrate having a conductive layer, A display layer sandwiched between the first substrate and the second substrate, A switch wiring that can be switched between a first state in which the conductive layer functions as a sensor electrode that detects a change in capacitance due to touch input and a second state in which the conductive layer functions as a counter electrode that generates a display driving voltage between the conductive layer and the pixel electrode, Comprising A touch panel display device characterized by the above.

2. The display layer includes a charged member, and the display is switched by the movement or rotation of the charged member when the display driving voltage is generated. The touch panel display device according to claim 1, characterized by the above.

3. The display layer is an electrophoretic type. The touch panel display device according to claim 2, characterized by the above.

4. The switching between the first state and the second state is performed in a time-division manner. The touch panel display device according to claim 1, characterized by the above.

5. Further comprising a control unit, The conductive layer is composed of a plurality of conductive layers, The control unit determines the position of the touch input based on the change in capacitance of each conductive layer in the first state. The touch panel display device according to any one of claims 1 to 4, characterized by the above.

6. In the first state, the control unit detects the change in capacitance of each conductive layer in a time-division manner, and then operates the switch wiring to switch to the second state. The touch panel display device according to claim 5, characterized by the above.

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