JP7415112B2 - incell touch panel - Google Patents

Description

The present disclosure relates to in-cell touch panels.

Conventionally, in-cell touch panels are known. Such an in-cell touch panel includes a thin film transistor, a thin film transistor substrate, a touch sensor electrode, and a counter substrate. A thin film transistor and a touch sensor are formed on a thin film transistor substrate. The in-cell touch panel alternately executes a display mode driven by a thin film transistor and a touch detection mode driven by a touch sensor in one frame period.

Further, a liquid crystal display device in which a viewing angle switching electrode is formed on a counter substrate is conventionally known. Such a liquid crystal display device is disclosed in Patent Document 1, for example.

In the liquid crystal display device of Patent Document 1, an AC voltage is output to the viewing angle switching electrode to control switching of the viewing angle, and there are two modes: a mode in which an image is displayed in a wide viewing angle, and an image in a narrow viewing angle. The mode in which the is displayed can be switched.

Patent No. 6848043

When an electrode that is not used for touch detection is formed on a counter substrate of a conventional in-cell touch panel as described in Patent Document 1, a capacitance that becomes a load is generated between the touch sensor electrode and the electrode on the counter substrate. arise. Therefore, due to the capacitance that acts as a load between the touch sensor electrode and the electrode on the counter substrate, the formation of capacitance between the touch sensor electrode and the indicator (such as a finger or a pen) is prevented. As a result, there is a problem in that the touch detection performance of the in-cell touch panel deteriorates.

Therefore, the present disclosure has been made to solve the above problems, and even when electrodes that are not used for touch detection are formed on the opposing substrate, it is possible to prevent the performance of touch detection from deteriorating. The purpose is to provide an in-cell touch panel.

In order to solve the above problems, an in-cell touch panel according to one aspect of the present disclosure includes a touch sensor substrate, a pixel electrode formed on the touch sensor substrate, a touch sensor electrode formed on the touch sensor substrate, and a touch sensor. A counter substrate disposed to face the substrate, a counter substrate electrode formed on the counter substrate and not used for touch detection, and a liquid crystal layer disposed between the touch sensor substrate and the counter substrate. a drive control circuit that supplies a drive signal to the touch sensor electrode; a display control circuit that supplies a display signal to the pixel electrode; a display mode in which the display control circuit supplies a display signal to the pixel electrode; and a drive control circuit. A mode switching control circuit that executes a touch detection mode in which a drive signal is supplied to a touch sensor electrode in a time-sharing manner, and a mode switching control circuit that executes a touch detection mode in which a drive signal is supplied to a touch sensor electrode in a time-sharing manner; A counter substrate electrode control circuit is provided that supplies a polarity signal to the counter substrate electrode or sets the potential of the counter substrate electrode in a floating state during a period in which a touch detection mode is executed.

According to the in-cell touch panel having the above configuration, the capacitance that acts as a load between the counter substrate electrode and the touch sensor electrode can be reduced, so that the formation of capacitance between the touch sensor electrode and the indicator is not prevented. As a result, even when electrodes that are not used for touch detection are formed on the opposing substrate, deterioration in touch detection performance can be prevented.

FIG. 1 is a block diagram of an in-cell touch panel device 100 in the first embodiment. FIG. 2A is a plan view showing the arrangement position of the counter substrate electrode 23. FIG. 2B is a plan view for explaining the arrangement position of the black matrix 22. FIG. 3A is a cross-sectional view of the panel module 1 taken along the line 1000-1000 in FIG. 2A. FIG. 3B is a cross-sectional view showing the state of the panel module 1 when performing white display in the narrow viewing angle mode. FIG. 3C is a cross-sectional view showing the state of the panel module 1 when performing black display in the narrow viewing angle mode. FIG. 3D is a cross-sectional view showing the state of the panel module 1 when performing white display in the wide viewing angle mode. FIG. 3E is a cross-sectional view showing the state of the panel module 1 when performing black display in the wide viewing angle mode. FIG. 4 is a diagram showing the configuration of a circuit formed on the touch sensor substrate 10. FIG. 5 is a schematic diagram showing the arrangement relationship between the counter substrate electrode 23 and the touch sensor electrode 12. FIG. 6 is a functional block diagram of the touch panel control circuit 3. FIG. 7 is a diagram showing an example of waveforms of a signal supplied from the touch panel control circuit 3 to the viewing angle control circuit 2 and a signal supplied from the viewing angle control circuit 2 to the panel module 1. FIG. 8 is a schematic diagram for explaining the principle of reducing the capacitance acting as a load on the counter substrate electrode 23 according to the first embodiment. FIG. 9 is a diagram for explaining the principle of generation of capacitance serving as a load by the electrode 123 of the first comparative example and the electrode 123a of the second comparative example. FIG. 10 is a block diagram of an in-cell touch panel device 200 according to a first modification of the first embodiment. FIG. 11 is a diagram showing an example of waveforms of a signal supplied from the touch panel control circuit 3 to the viewing angle control circuit 202 and a signal supplied from the viewing angle control circuit 202 to the panel module 1. FIG. 12 is a block diagram of an in-cell touch panel device 300 according to a second modification of the first embodiment. FIG. 13 is a diagram showing an example of waveforms of a signal supplied from the touch panel control circuit 3 to the viewing angle control circuit 302 and a signal supplied from the viewing angle control circuit 302 to the panel module 1. FIG. 14 is a block diagram of an in-cell touch panel device 400 according to the second embodiment. FIG. 15 is a block diagram of the touch panel control circuit 403 of the second embodiment. FIG. 16 is a schematic diagram for explaining the principle of reducing the capacitance that becomes a load on the counter substrate electrode 423 according to the second embodiment. FIG. 17 is a diagram showing an example of a signal waveform in the in-cell touch panel device 400 according to the second embodiment. FIG. 18 is a schematic diagram showing the configuration of the counter substrate electrode 423. FIG. 19 is a diagram for explaining the measurement results. FIG. 20 is a sectional view showing the configuration of a panel module 501 according to a modification of the first and second embodiments.

Embodiments of the present disclosure will be described below based on the drawings. Note that the present disclosure is not limited to the following embodiments, and design changes can be made as appropriate within the scope of satisfying the configuration of the present disclosure. In addition, in the following description, the same parts or parts having similar functions will be denoted by the same reference numerals in different drawings, and repeated description thereof will be omitted. Furthermore, the configurations described in the embodiments and modified examples may be combined or modified as appropriate without departing from the gist of the present disclosure. Further, in order to make the explanation easier to understand, the configuration is shown in a simplified or schematic manner, and some structural members are omitted in the drawings referred to below. Furthermore, the dimensional ratios between the constituent members shown in each figure do not necessarily represent the actual dimensional ratios.

[First embodiment]
FIG. 1 is a block diagram of an in-cell touch panel device 100 in the first embodiment. As shown in FIG. 1, the in-cell touch panel device 100 includes a panel module 1, a viewing angle control circuit 2, and a touch panel control circuit 3. Note that although the viewing angle control circuit 2 and the touch panel control circuit 3 are illustrated as separate circuits in FIG. Both functions may be realized.

FIG. 2A is a plan view showing the arrangement position of the counter substrate electrode 23. FIG. 2B is a plan view for explaining the arrangement position of the black matrix 22. FIG. 3A is a cross-sectional view of the panel module 1 taken along the line 1000-1000 in FIG. 2A. As shown in FIG. 3A, the panel module 1 includes a touch sensor substrate 10, a counter substrate 20, and a liquid crystal layer 30 sandwiched between the touch sensor substrate 10 and the counter substrate 20. Further, the panel module 1 is provided with an optical member (not shown) such as a polarizing plate so as to sandwich the touch sensor substrate 10 and the counter substrate 20 . Further, a cover glass (not shown) is provided on the surface of the panel module 1 (in the Z1 direction from the panel module 1). Further, a backlight (not shown) is provided on the back surface of the panel module 1 (in the Z2 direction from the panel module 1). Note that in FIG. 3A, illustration of the liquid crystal molecules 30a, the insulating layer 13, and the pixel electrode 11d is omitted.

The image is configured so that the user can view the image from the front side of the panel module 1. Then, on the surface (touch surface) of the panel module 1, a touch operation by, for example, a finger (pointer) is accepted. Furthermore, in the panel module 1, the driving method for the liquid crystal molecules 30a included in the liquid crystal layer 30 is a transverse electric field driving method. In order to realize the transverse electric field driving method, a thin film transistor layer 11 (hereinafter referred to as "TFT layer 11") for forming an electric field is formed on the touch sensor substrate 10.

3B to 3E are cross-sectional views showing the structure of the panel module 1. As shown in FIGS. 3B to 3E, the panel module 1 includes a TFT layer 11, a touch sensor electrode 12, and a pixel electrode 11d stacked on the touch sensor electrode 12 with an insulating layer 13 in between. The touch sensor electrode 12 and the pixel electrode 11d are laminated with an insulating layer 13 in between, and constitute an FFS (Fringe Field Switching) type electrode structure. Examples of the material of the insulating layer 13 include inorganic materials such as silicon oxide and silicon nitride.

It is preferable that the touch sensor electrode 12 is a solid electrode. The touch sensor electrode 12 may be arranged for each of a plurality of picture elements, or may be arranged in common for a plurality of picture elements. The above-mentioned solid electrode refers to an electrode in which a slit or opening is not provided in a region that overlaps with an optical opening of a picture element at least in plan view. Examples of the material for the touch sensor electrode 12 include transparent conductive materials such as indium tin oxide (ITO) and indium zinc oxide (IZO).

FIG. 4 is a diagram showing the configuration of a circuit formed on the touch sensor substrate 10. A plurality of gate lines 11a and a plurality of data lines 11b intersecting the plurality of gate lines 11a are formed on the touch sensor substrate 10. A plurality of pixels P defined by a plurality of data lines 11b and a plurality of gate lines 11a are formed on the touch sensor substrate 10. The pixel P is provided with a thin film transistor (TFT) 11c and a pixel electrode 11d. The pixel electrode 11d has a capacitance between it and the touch sensor electrode 12 functioning as a counter electrode. Further, the touch sensor electrode 12 is a common electrode arranged in common to the plurality of pixel electrodes 11d. Furthermore, the gate of the TFT 11c is connected to the gate line 11a, the source of the TFT 11c is connected to the data line 11b, and the drain of the TFT 11c is connected to the pixel electrode 11d. The pixel electrode 11d and the touch sensor electrode 12 are each made of, for example, a transparent conductive film such as ITO or a mesh-like metal film. Here, the TFT layer 11 shown in FIG. 3A includes a layer in which the gate line 11a is formed, a layer in which the data line 11b is formed, a layer in which the TFT 11c is formed, and a layer in which the pixel electrode 11d is formed. include.

Further, as shown in FIG. 3A, a plurality of color filters 21 are formed on the liquid crystal layer 30 side of the counter substrate 20. The plurality of color filters 21 include a red filter, a green filter, and a blue filter. Further, a black matrix 22 is formed between each of the plurality of color filters 21. Further, a counter substrate electrode 23 is formed on the liquid crystal layer 30 side of the black matrix 22 . The black matrix 22 is made of, for example, a resin material having light-shielding properties. The counter substrate electrode 23 is made of, but not limited to, a metal film or a transparent conductive film such as ITO.

As shown in FIG. 2A, the counter substrate electrode 23 is formed at a position overlapping a part of the black matrix 22 in plan view. Specifically, as shown in FIGS. 2A and 2B, the counter substrate electrode 23 is not arranged at a position overlapping the black matrix 22 arranged between the plurality of color filters 21 in the X direction. The counter substrate electrode 23 is arranged at a position overlapping the black matrix 22 arranged between the plurality of color filters 21 in the Y direction. According to this configuration, since the counter substrate electrode 23 is arranged at a position overlapping with the black matrix 22 for the purpose of blocking light, even if light is absorbed or diffused by the counter substrate electrode 23, the display is not affected. As a result, even when the counter substrate electrode 23 is placed on the counter substrate 20, it does not affect the display. Further, since the counter substrate electrode 23 does not block the light incident on the color filter 21 or the light emitted from the color filter 21, even if the counter substrate electrode 23 is placed on the counter substrate 20, the display will not be affected. .

FIG. 5 is a schematic diagram showing the arrangement relationship between the counter substrate electrode 23 and the touch sensor electrode 12. As shown in FIG. 5, the counter substrate electrode 23 is formed into a ladder shape when viewed from above. Further, the touch sensor electrodes 12 are formed in a matrix shape when viewed from above. Further, as shown in FIGS. 2 and 5, a slit 23a is formed in the counter substrate electrode 23 at a position overlapping the color filter 21 in plan view.

FIG. 6 is a functional block diagram of the touch panel control circuit 3. As shown in FIG. 6, the touch panel control circuit 3 includes a display control section 31, a drive control section 32, and a mode switching control section 33. The display control section 31 supplies a data signal (display signal) to the TFT 11c via the data line 11b. Furthermore, the display control unit 31 supplies a gate signal to the TFT 11c via the gate line 11a, thereby turning on the TFT 11c and supplying a data signal to the pixel electrode 11d. Further, the drive control section 32 supplies a drive signal to the touch sensor electrode 12. The drive signal has, for example, a pulse-like voltage waveform. The drive control unit 32 then detects a touch based on the drive signal whose waveform has changed depending on the capacitance formed between the touch sensor electrode 12 and the indicator. The mode switching control unit 33 executes the display mode and the touch detection mode in a time-sharing manner. The display mode is a mode in which the display control unit 31 supplies data signals to the pixel electrodes 11d. The touch detection mode is a mode in which the drive control unit 32 supplies a drive signal to the touch sensor electrode 12. Note that although the display control section 31, drive control section 32, and mode switching control section 33 are illustrated as functional blocks within the touch panel control circuit 3 in FIG. 6, separate circuits are configured for each function. You can.

FIG. 7 is a diagram showing an example of waveforms of a signal supplied from the touch panel control circuit 3 to the viewing angle control circuit 2 and a signal supplied from the viewing angle control circuit 2 to the panel module 1. As shown in FIG. 7, a voltage Vcom is applied to the touch sensor electrode 12 from the touch panel control circuit 3. The viewing angle control circuit 2 supplies the opposing substrate electrode 23 with a viewing angle control signal S1 for controlling the viewing angle. For example, when the viewing angle of the panel module 1 is set to a narrow viewing angle (hereinafter referred to as "narrow viewing angle mode"), the viewing angle control circuit 2 sends the viewing angle control signal S1 to the counter substrate electrode 23. By supplying the voltage, a potential difference is generated between the counter substrate electrode 23 and the touch sensor electrode 12 (common electrode). As a result, an electric field is generated in the liquid crystal layer 30, and the viewing angle of the panel module 1 is narrowed. For example, when displaying white in the narrow viewing angle mode, the viewing angle control circuit 2 applies a constant voltage (common voltage Vcom) to either the touch sensor electrode 12 or the pixel electrode 11d, and applies a constant voltage (common voltage Vcom) to the other. Control is performed to apply a potential different from the common voltage Vcom to the common voltage Vcom. Further, the viewing angle control circuit 2 performs control to apply an alternating current voltage to the counter substrate electrode 23. The absolute value of the AC voltage is preferably different from the absolute value of the voltage applied to the touch sensor electrode 12 and the pixel electrode 11d. For example, when a common voltage Vcom is applied to the pixel electrode 11d, an AC voltage of 4V is applied to the touch sensor electrode 12 with respect to the common voltage Vcom, and an AC voltage of 4V is applied to the counter substrate electrode 23 with respect to the common voltage Vcom. An alternating current voltage of 6V is applied. As a result, as shown in FIG. 3B, a fringe electric field is formed between the touch sensor electrode 12 and the pixel electrode 11d, and a liquid crystal layer is formed between the counter substrate electrode 23 and the touch sensor electrode 12 and the pixel electrode 11d. An oblique electric field is formed in the thickness direction of 30. As a result, the image on the panel module 1 can be observed from a narrow viewing angle range. On the other hand, since the liquid crystal molecules 30a of the liquid crystal layer 30 form an angle with respect to the touch sensor substrate 10, when the panel module 1 is observed from a wide viewing angle range, changes in the image such as extremely low contrast may occur. image is difficult to observe.

When displaying black in the narrow viewing angle mode, for example, the viewing angle control circuit 2 performs control to apply a common voltage Vcom to the touch sensor electrode 12 and the pixel electrode 11d. Further, the viewing angle control circuit 2 performs control to apply an alternating current voltage to the counter substrate electrode 23. The absolute value of the AC voltage is preferably different from the absolute value of the common voltage Vcom. As an example, as shown in FIG. 3C, when the common voltage Vcom is applied to the pixel electrode 11d, the common voltage Vcom (voltage of 0V with respect to the common voltage) is also applied to the touch sensor electrode 12, and the counter substrate electrode 23 is applied with an AC voltage of 6V with respect to the common voltage Vcom. As a result, an oblique electric field is formed between the counter substrate electrode 23, the touch sensor electrode 12, and the pixel electrode 11d. The liquid crystal molecules 30a of the liquid crystal layer 30 form an angle with respect to the touch sensor substrate 10 due to the above-mentioned oblique electric field. Since the alignment direction of the liquid crystal molecules 30a does not change within the plane of the liquid crystal layer 30, light from the back surface of the touch sensor substrate 10 is not transmitted, and a black display is performed. Since the liquid crystal molecules 30a form an angle with respect to the touch sensor substrate 10, when the panel module 1 is observed from a wide viewing angle range, a whitish display is observed than a black display observed from a narrow viewing angle range. Ru.

When displaying white in the wide viewing angle mode, for example, the viewing angle control circuit 2 applies a constant voltage (common voltage Vcom) to either the touch sensor electrode 12 or the pixel electrode 11d, and applies a constant voltage (common voltage Vcom) to the other. Control is performed to apply a potential different from the common voltage Vcom. The viewing angle control circuit 2 also performs control to apply a constant voltage (common voltage Vcom) common to the touch sensor electrode 12 and the pixel electrode 11d to the counter substrate electrode 23. For example, when the common voltage Vcom is applied to the pixel electrode 11d, an AC voltage of 4V is applied to the touch sensor electrode 12 with respect to the common voltage Vcom, and the common voltage Vcom is applied to the counter substrate electrode 23, which is common to the touch sensor electrode 12. A common voltage Vcom is applied. As a result, a fringe electric field is formed between the touch sensor electrode 12 and the pixel electrode 11d, as shown in FIG. 3D. On the other hand, unlike the narrow viewing angle mode, the electric field in the thickness direction of the liquid crystal layer 30 is small. Therefore, the liquid crystal molecules 30a change their alignment direction while being aligned parallel to the touch sensor substrate 10 due to the electric field formed between the touch sensor electrode 12 and the pixel electrode 11d.

For black display in the wide viewing angle mode, for example, the viewing angle control circuit 2 performs control to apply the common voltage Vcom to the pixel electrode 11d and the touch sensor electrode 12. Furthermore, the viewing angle control circuit 2 performs control to apply a constant voltage common to the touch sensor electrode 12 or the pixel electrode 11d to the counter substrate electrode 23 as well. As shown in FIG. 3E, since no electric field is generated in the liquid crystal layer 30, the liquid crystal molecules 30a are aligned in the initial alignment direction. The initial alignment direction is preferably parallel to the touch sensor substrate 10 and parallel to the absorption axis of a polarizing plate (not shown) in plan view.

When the viewing angle of the panel module 1 is set to a wide viewing angle, the viewing angle control circuit 2 supplies a signal having a smaller amplitude than the viewing angle control signal S1 shown in FIG. 7 to the counter substrate electrode 23. Then, the potential difference between the counter substrate electrode 23 and the touch sensor electrode 12 (common electrode) to which the voltage Vcom is applied is reduced, or the potential difference is made zero. This widens the viewing angle of the panel module 1.

The white display in the narrow viewing angle mode and the white display in the wide viewing angle mode described above can be switched by applying a voltage to the counter substrate electrode 23. Similarly, black display in the narrow viewing angle mode and black display in the wide viewing angle mode can be switched by applying a voltage to the counter substrate electrode 23. The same applies to halftone display. The narrow viewing angle mode and the wide viewing angle mode can be switched depending on whether or not an alternating current voltage is applied to the counter substrate electrode 23.

Further, the display control unit 31 transmits a frame synchronization signal S2 indicating the timing at which the frame period changes to the viewing angle control circuit 2. The viewing angle control circuit 2 then inverts the polarity of the voltage of the viewing angle control signal S1 with respect to the voltage Vcom in accordance with the frame synchronization signal S2. In other words, the viewing angle control circuit 2 inverts the polarity of the voltage of the viewing angle control signal S1 every frame period.

Further, the drive control unit 32 transmits a drive synchronization signal S3 indicating the timing of supplying the drive signal to the touch sensor electrode 12 to the viewing angle control circuit 2. Further, the mode switching control unit 33 transmits a mode switching synchronization signal S4 indicating the timing of switching between the display mode and the touch detection mode to the viewing angle control circuit 2. The display mode and the touch detection mode are executed in a time-sharing manner during one frame period. For example, the display mode and the touch detection mode are alternately executed multiple times during one frame period. Based on the mode switching synchronization signal S4, the viewing angle control circuit 2 determines whether the current time is a period T1 in which the display mode is being executed by the touch panel control circuit 3, or a period in which the touch detection mode is being executed. It is determined whether it is T2.

Here, in the first embodiment, the viewing angle control circuit 2 supplies the load reduction signal S5 to the counter substrate electrode 23 during the period T2 in which the touch detection mode is executed. This load reduction signal S5 is a signal that is synchronized with the drive signal and has the same polarity as the drive signal. Here, the drive synchronization signal S3 is a signal that is synchronized with the drive signal and has the same polarity as the drive signal. Then, the viewing angle control circuit 2 generates a load reduction signal S5 by superimposing a signal synchronized with the drive synchronization signal S3 and having the same polarity as the drive synchronization signal S3 on the viewing angle control signal S1. The drive signal has different waveforms in period T2a and period T2b of period T2, for example, like the drive synchronization signal S3 shown in FIG. For example, in the period T2a, the drive signal does not include a pulsed voltage, and in the period T2b, the drive signal includes a pulsed voltage. Furthermore, a plurality of periods T2b are provided in one frame period. As shown in FIG. 7, the frequency (width and number of pulses) of the drive signal (drive synchronization signal S3) in the plurality of periods T2b may have a different magnitude for each period T2b. As shown in FIG. 7, the load reduction signal S5 has a base voltage Vb that is a predetermined voltage drop from the viewing angle control signal S1 in the period T2a, and the base voltage Vb has the above-mentioned pulsed voltage in the period T2b. It has a voltage value that is applied in synchronization with a voltage having the same polarity as the pulsed voltage and the same amplitude as the pulsed voltage.

FIG. 8 is a schematic diagram for explaining the principle by which the capacitance acting as a load on the counter substrate electrode 23 according to the first embodiment is reduced. FIG. 9 is a diagram for explaining the principle of generation of capacitance serving as a load by the electrode 123 of the first comparative example and the electrode 123a of the second comparative example. The electrode 123 of the first comparative example is connected to ground (GND). As a result, the potential of the electrode 123 in the first comparative example is the ground voltage. Furthermore, the viewing angle control signal is applied to the electrode 123a of the second comparative example even during the period in which the touch detection mode is being executed. The configurations of the first comparative example and the second comparative example are described to explain the functions and effects of the first embodiment, and the configurations of the first comparative example and the second comparative example are assumed to be conventional configurations. It's not something I admit.

The ground voltage and the voltage of the drive signal have different values and waveforms. Furthermore, the voltages of the viewing angle control signal and the drive signal have different values and waveforms. Therefore, as shown in FIG. 9, the potential of the electrode 123 of the first comparative example and the potential of the electrode 123a of the second comparative example are both different values from the potential of the touch sensor electrode 112 to which the drive signal is applied. Become. As a result, an electric field is generated between the electrode 123 and the touch sensor electrode 112, and a capacitance CL serving as a load is generated. Due to the capacitance CL acting as a load, when the indicator Q touches the panel module, the formation of capacitance between the indicator Q and the touch sensor electrode 112 is inhibited, and the touch detection signal decreases. It ends up.

On the other hand, as shown in FIG. 7, the counter substrate electrode 23 according to the first embodiment has a signal that is synchronized with the drive synchronization signal S3 applied to the touch sensor electrode 12 and has the same polarity as the drive synchronization signal S3. A load reduction signal S5, which is a signal, is applied. Therefore, as shown in FIG. 8, no electric field is generated between the counter substrate electrode 23 and the touch sensor electrode 12, or even if an electric field is generated, the size thereof is minute. As a result, the capacitance that is a load on the touch detection (signal) caused by the counter substrate electrode 23 is reduced, and when the indicator Q touches the panel module 1, it is possible to It becomes possible to detect a touch on the body Q. Note that in FIG. 8, illustration of the liquid crystal molecules 30a, the insulating layer 13, and the pixel electrode 11d is omitted.

[First modification of the first embodiment]
Next, the configuration of an in-cell touch panel device 200 according to a first modification of the first embodiment will be described with reference to FIGS. 10 and 11. Components that are the same as those in the first embodiment are given the same reference numerals and descriptions thereof will be omitted. FIG. 10 is a block diagram of an in-cell touch panel device 200 according to a first modification of the first embodiment. FIG. 11 is a diagram showing an example of waveforms of a signal supplied from the touch panel control circuit 3 to the viewing angle control circuit 202 and a signal supplied from the viewing angle control circuit 202 to the panel module 1.

As shown in FIG. 10, the in-cell touch panel device 200 includes a viewing angle control circuit 202.

Here, in the first embodiment, during the period T2a, the base voltage Vb, which is a predetermined voltage drop from the viewing angle control signal S1, is supplied to the counter substrate electrode 23, and during the period T2b, the base voltage Vb is supplied to the counter substrate electrode 23 in synchronization with the drive signal. Although the viewing angle control circuit 2 is configured to supply a pulse voltage having a positive polarity with respect to the base voltage Vb to the counter substrate electrode 23, the present disclosure is not limited thereto. As shown in FIG. 11, the viewing angle control circuit 202 supplies the same voltage as the viewing angle control signal S1 to the counter substrate electrode 23 as the base voltage Vb2 of the load reduction signal S5a during the period T2a, and supplies the same voltage as the viewing angle control signal S1 to the counter substrate electrode 23 during the period T2b. , a load reduction signal S5a, which is a voltage obtained by superimposing a positive polarity pulse voltage in synchronization with the drive signal on the base voltage Vb2, is supplied to the counter substrate electrode 23. The configuration of this first modification also makes it possible to reduce the capacitance that causes a load between the opposing substrate electrode 23 and the touch sensor electrode 12. As a result, the formation of a capacitance between the touch sensor electrode 12 and the indicator is not hindered, so even when the electrode is formed on the counter substrate 20, deterioration in touch detection performance can be prevented. Further, in the first embodiment, in order to generate the load reduction signal S5, two levels of voltage are applied to each of the positive polarity voltage and the negative polarity voltage of the viewing angle control signal S1. A power source (a power source that outputs a total of four levels) is required. On the other hand, in the first modification of the first embodiment, in order to generate the load reduction signal S5a, 1 What is necessary is to prepare a power supply that applies two levels of voltage (a power supply that outputs two levels in total). As a result, compared to the first embodiment, the configuration of the viewing angle control circuit 202 can be simplified and costs can be reduced.

[Second modification of the first embodiment]
Next, the configuration of an in-cell touch panel device 300 according to a second modification of the first embodiment will be described with reference to FIGS. 12 and 13. Components that are the same as those in the first embodiment are given the same reference numerals and descriptions thereof will be omitted. FIG. 12 is a block diagram of an in-cell touch panel device 300 according to a second modification of the first embodiment. FIG. 13 is a diagram showing an example of waveforms of a signal supplied from the touch panel control circuit 3 to the viewing angle control circuit 302 and a signal supplied from the viewing angle control circuit 302 to the panel module 1.

As shown in FIG. 12, the in-cell touch panel device 300 includes a viewing angle control circuit 302.

As shown in FIG. 13, the viewing angle control circuit 302 applies the same voltage as the viewing angle control signal S1 to the load reduction signal S5b during a period T11 in which the voltage of the viewing angle control signal S1 has a positive polarity with respect to the voltage Vcom. is supplied to the counter substrate electrode 23 as the base voltage Vb3. Furthermore, in a period T12 in which the voltage of the viewing angle control signal S1 has a negative polarity with respect to the voltage Vcom, a voltage obtained by lowering the voltage of the viewing angle control signal S1 by the same value as the amplitude of the drive signal is applied to the load reduction signal S5b. It is supplied to the counter substrate electrode 23 as the base voltage Vb4. The configuration of this second modification also makes it possible to reduce the capacitance that causes a load between the opposing substrate electrode 23 and the touch sensor electrode 12. As a result, the formation of a capacitance between the touch sensor electrode 12 and the indicator is not hindered, so even when the electrode is formed on the counter substrate 20, deterioration in touch detection performance can be prevented. In the second modification of the first embodiment, in order to generate the load reduction signal S5b, one level is set for each of the positive polarity voltage and the negative polarity voltage of the viewing angle control signal S1. What is necessary is to prepare a power supply that applies a voltage (a power supply that outputs two types of levels in total). As a result, compared to the first embodiment, the configuration of the viewing angle control circuit 302 can be simplified and costs can be reduced.

[Second embodiment]
Next, the configuration of the in-cell touch panel device 400 according to the second embodiment will be described with reference to FIGS. 14 to 18. Components that are the same as those in the first embodiment are given the same reference numerals and descriptions thereof will be omitted. FIG. 14 is a block diagram of an in-cell touch panel device 400 according to the second embodiment. FIG. 15 is a block diagram of the touch panel control circuit 403 of the second embodiment. FIG. 16 is a schematic diagram for explaining the principle by which the capacitance acting as a load on the counter substrate electrode 423 is reduced according to the second embodiment. FIG. 17 is a diagram showing an example of a signal waveform in the in-cell touch panel device 400 according to the second embodiment. FIG. 18 is a schematic diagram showing the configuration of the counter substrate electrode 423.

As shown in FIG. 14, in-cell touch panel device 400 includes a panel module 401, a viewing angle control circuit 402, and a touch panel control circuit 403. Further, as shown in FIG. 15, the touch panel control circuit 403 includes a drive control section 432. The drive control unit 432 does not transmit the drive synchronization signal S3 to the viewing angle control circuit 402, unlike the first embodiment.

Further, as shown in FIG. 16, the panel module 401 includes a counter substrate electrode 423. In the second embodiment, the viewing angle control circuit 402 supplies the viewing angle control signal S1 to the counter substrate electrode 423 during a period T1 during which the display mode is executed, as shown in FIG. During the period T2 during which the touch detection mode is executed, the potential of the counter substrate electrode 423 is set to a floating state. The term "floating state" shall mean a state in which no voltage is directly applied from a voltage source and the device is not connected to ground. Note that in FIG. 16, illustration of the liquid crystal molecules 30a, the insulating layer 13, and the pixel electrode 11d is omitted.

Here, as shown in FIG. 18, one opposing substrate electrode 423 and the plurality of touch sensor electrodes 12 are arranged to face each other. Therefore, capacitance is generated between one opposing substrate electrode 423 and the plurality of touch sensor electrodes 12. Here, when the drive signal (see FIG. 17) is supplied to the plural touch sensor electrodes 12, the potential of the counter substrate electrode 423 is in a floating state, so the capacitance between the plural touch sensor electrodes 12 As a result, the potential of the counter substrate electrode 423 becomes a voltage S5c having the same waveform as the drive signal. Therefore, if the potential of the counter substrate electrode 423 is set to a floating state, the result will be the same as the state in which the load reduction signal S5 of the first embodiment is applied to the counter substrate electrode 423. That is, even if a capacitance is formed between the counter substrate electrode 423 and the plurality of touch sensor electrodes 12, this capacitance does not become a load. As a result, even with the configuration of the second embodiment, even when electrodes are formed on the counter substrate 20, deterioration in touch detection performance can be prevented.

Further, according to the configuration of the second embodiment, unlike the first embodiment, control to synchronize with the drive signal and processing to generate the load reduction signal S5 in the viewing angle control circuit 402 are unnecessary, and the viewing angle control circuit 402 It is possible to simplify the circuit configuration and reduce costs. Note that the other configurations and effects are the same as those in the first embodiment.

[Results of comparison with comparative example]
Next, with reference to FIG. 19, measurement of signals detected by touch sensor electrodes (hereinafter referred to as "touch signals") in the first embodiment, the second embodiment, the first comparative example, and the second comparative example Explain the results. FIG. 19 is a diagram for explaining the measurement results.

The touch signal detected by the touch sensor electrode was measured while the potential of the electrode 123 was set to the ground voltage by connecting the electrode 123 (see FIG. 9) of the first comparative example to the ground (GND). As a result, as shown in FIG. 19, a capacitance exceeding the detection limit of the touch panel control circuit was applied to the touch sensor electrode, and the measured value of the touch signal became an overflow (unmeasurable value). Further, while supplying a viewing angle control signal to the electrode 123a (see FIG. 9) of the second comparative example, the touch signal detected by the touch sensor electrode was measured. As a result, in the second comparative example as well, a capacitance exceeding the detection limit of the touch panel control circuit was applied to the touch sensor electrode, and the measured value of the touch signal became an overflow (unmeasurable value).

Further, the touch signal detected by the touch sensor electrode 12 was measured while supplying the load reduction signal S5 to the counter substrate electrode 23 (see FIG. 3A) of the first embodiment. As a result, as shown in FIG. 19, the touch signal had a value within a touch detectable range. Further, the touch signal detected by the touch sensor electrode 12 was measured while the potential of the counter substrate electrode 423 (see FIG. 16) of the second embodiment was set to floating. As a result, as shown in FIG. 19, the touch signal had a value within a touch detectable range. Therefore, in the first embodiment and the second embodiment, it has been found that touch detection is possible even when the electrodes are arranged on the counter substrate 20.

[Modified example]
Although the embodiments of the invention have been described above, the embodiments described above are merely examples for carrying out the invention. Therefore, without being limited to the embodiments described above, the embodiments described above can be modified and implemented as appropriate without departing from the spirit thereof. Modifications of the above-described embodiment will be described below.

(1) In the first and second embodiments described above, an example was shown in which the counter substrate electrode is arranged closer to the liquid crystal layer than the color filter and the black matrix, but the present disclosure is not limited to this. For example, as in a modified panel module 501 shown in FIG. 20, the counter substrate electrode 523 may be arranged closer to the counter substrate 20 (Z1 direction) than the color filter 21 and the black matrix 22, or, although not shown, , the counter substrate electrode may be arranged in the same layer as the color filter and the black matrix. For example, while the flattening film 524 covers the liquid crystal layer 30 side of the counter substrate electrode 523, the color filter 21 and the black matrix 22 may be further formed on the liquid crystal layer 30 side. Note that in FIG. 20, illustration of the liquid crystal molecules 30a, the insulating layer 13, and the pixel electrode 11d is omitted.

(2) In the first and second embodiments described above, as shown in FIGS. 5 and 18, an example is shown in which one counter substrate electrode is provided in the panel module, but the present disclosure is not limited to this. For example, a panel module may be provided with a plurality of opposing substrate electrodes.

(3) In the first and second embodiments described above, an example in which a slit portion is provided in the counter substrate electrode is shown, but the present disclosure is not limited to this. For example, the counter substrate electrode does not need to be provided with a slit portion.

(4) In the first and second embodiments described above, an example was shown in which the counter substrate electrode is arranged at a position where it does not overlap with the color filter in plan view but overlaps with the black matrix, but the present disclosure is not limited to this. . For example, when the counter substrate electrode is formed of a transparent electrode film, the counter substrate electrode may be placed at a position overlapping the color filter in plan view. In this case, the counter substrate electrode does not need to be placed at a position overlapping the black matrix.

(5) In the first embodiment, an example is shown in which the amplitude of the voltage of the load reduction signal S5 is the amplitude of the voltage of the drive signal, but the present disclosure is not limited to this. For example, as long as the load reduction signal is a signal synchronized with the drive signal and has the same polarity as the drive signal, the voltage amplitude of the load reduction signal may be different from the voltage amplitude of the drive signal.

(6) In the first and second embodiments described above, an example was shown in which the viewing angle control signal is supplied to the counter substrate electrode in the display mode, but the present disclosure is not limited to this. That is, it is not necessary to supply the viewing angle control signal to the counter substrate electrode in the display mode, or a signal different from the viewing angle control signal may be supplied to the counter substrate electrode.

(7) In the first and second embodiments described above, as shown in FIGS. 2A and 2B, an example in which the counter substrate electrode is arranged at a position overlapping a black matrix arranged between a plurality of color filters in the Y direction is used. Although shown, the present disclosure is not limited thereto. That is, the counter substrate electrode may be arranged at a position overlapping the black matrix arranged between the plurality of color filters in the X direction.

The in-cell touch panel described above can also be explained as follows.

The in-cell touch panel according to the first configuration includes a touch sensor substrate, a pixel electrode formed on the touch sensor substrate, a touch sensor electrode formed on the touch sensor substrate, and a counter substrate disposed opposite to the touch sensor substrate. , a counter substrate electrode formed on the counter substrate that is not used for touch detection, a liquid crystal layer disposed between the touch sensor substrate and the counter substrate, and a drive signal that supplies a drive signal to the touch sensor electrode. a display control circuit that supplies a display signal to the pixel electrode; a display mode in which the display control circuit supplies the display signal to the pixel electrode; and a drive control circuit that supplies the drive signal to the touch sensor electrode. a mode switching control circuit that executes the touch detection mode in a time-division manner, and supplies a signal that is synchronized with the drive signal and has the same polarity as the drive signal to the opposing substrate electrode during the period in which the touch detection mode is executed; Alternatively, a counter substrate electrode control circuit is provided that sets the potential of the counter substrate electrode in a floating state during a period in which the touch detection mode is executed (first configuration).

According to the first configuration, when a signal synchronized with the drive signal and having the same polarity as the drive signal is supplied to the counter substrate electrode, a load is generated between the counter substrate electrode and the touch sensor electrode. Capacity can be reduced. Further, even when the potential of the counter substrate electrode is set to a floating state, the capacitance that causes a load between the counter substrate electrode and the touch sensor electrode can be reduced. As a result, the formation of capacitance between the touch sensor electrode and the indicator is not hindered, so even when electrodes that are not used for touch detection are formed on the opposing substrate, deterioration in touch detection performance can be prevented. .

In the first configuration, the in-cell touch panel may further include a black matrix disposed on the counter substrate, and the counter substrate electrode may be disposed at a position overlapping the black matrix in plan view (second composition).

According to the second configuration, the counter substrate electrode is arranged at a position overlapping with the black matrix intended for light shielding, so even if light is absorbed or diffused by the counter substrate electrode, the display is not affected. As a result, even if the counter substrate electrode is placed on the counter substrate, it does not affect the display.

In the first or second configuration, the in-cell touch panel may further include a color filter disposed on the counter substrate, and the counter substrate electrode may be disposed at a position that does not overlap the color filter in plan view. (Third configuration).

According to the third configuration, the counter substrate electrode does not block the light incident on the color filter or the light emitted from the color filter, so even if the counter substrate electrode is arranged on the counter substrate, the display is not affected. I won't give it.

In any one of the first to third configurations, the counter substrate electrode control circuit supplies a viewing angle control signal for changing the viewing angle to the counter substrate electrode during a period in which the display mode is executed. (fourth configuration).

According to the fourth configuration, the viewing angle of the in-cell touch panel can be changed without degrading touch detection performance.

In the fourth configuration, the counter substrate electrode control circuit sends the first viewing angle control signal to the counter substrate electrode when the viewing angle is set to a narrow viewing angle while the display mode is being executed. By supplying, a potential difference is generated between the counter substrate electrode and the touch sensor electrode, and when the viewing angle is set to a wide viewing angle while the display mode is being executed, the first viewing angle control is performed. It may be configured to supply a second viewing angle control signal having a smaller amplitude than the signal to the opposing substrate electrode or to make the potential difference zero (fifth configuration).

In any one of the first to third configurations, the counter substrate electrode control circuit lowers the first base voltage by a predetermined voltage from the viewing angle control signal during a period in which the touch detection mode is executed. The first base voltage may be configured to be supplied to the counter substrate electrode, and to supply the first base voltage with a pulsed voltage that is synchronized with the drive signal, has the same polarity, and has the same amplitude (sixth base voltage). composition).

In any one of the first to third configurations, the counter substrate electrode control circuit supplies the second base voltage, which is the same as the viewing angle control signal, to the counter substrate electrode during a period in which the touch detection mode is executed. However, it may be configured to supply a voltage obtained by superimposing a positive polarity pulse voltage on the second base voltage in synchronization with the drive signal to the opposing substrate electrode (seventh configuration).

In any one of the first to third configurations, the counter substrate electrode control circuit is configured to control the voltage of the viewing angle control signal during a period in which the touch detection mode is executed and the voltage of the viewing angle control signal is positive with respect to the voltage of the touch sensor electrode. During the period when the polarity of the viewing angle control signal is the same as that of the viewing angle control signal, the second base voltage that is the same as the polarity of the viewing angle control signal is supplied to the opposite substrate electrode. The third base voltage may be configured to supply the counter substrate electrode with a third base voltage that is lowered from the voltage of the viewing angle control signal by the same value as the amplitude of the drive signal during a period in which the voltage has a negative polarity with respect to the voltage. (Eighth configuration).

DESCRIPTION OF SYMBOLS 1,401,501... Panel module, 2,202,302,402... Viewing angle control circuit, 3,403... Touch panel control circuit, 10... Touch sensor board, 11d... Pixel electrode, 12... Touch sensor electrode, 20... Opposing Substrate, 21...Color filter, 22...Black matrix, 23,423,523...Counter substrate electrode, 30...Liquid crystal layer, 31...Display control section, 32,432...Drive control section, 33...Mode switching control section, 100, 200, 300, 400...In-cell touch panel device, S1...Viewing angle control signal, S3...Drive synchronization signal, S4...Mode switching synchronization signal, S5, S5a, S5b...Load reduction signal

Claims (9)

a touch sensor board;
a pixel electrode formed on the touch sensor substrate;
a touch sensor electrode formed on the touch sensor substrate;
a counter substrate disposed opposite to the touch sensor substrate;
a counter substrate electrode formed on the counter substrate and not used for touch detection;
a liquid crystal layer disposed between the touch sensor substrate and the counter substrate;
a drive control circuit that supplies a drive signal to the touch sensor electrode;
a display control circuit that supplies a display signal to the pixel electrode;
Mode switching control for time-divisionally executing a display mode in which the display control circuit supplies the display signal to the pixel electrode and a touch detection mode in which the drive control circuit supplies the drive signal to the touch sensor electrode. circuit and
While the touch detection mode is being executed, a signal that is synchronized with the drive signal and having the same polarity as the drive signal is supplied to the counter substrate electrode, or the touch detection mode is being executed. An in-cell touch panel, comprising: a counter substrate electrode control circuit that sets the potential of the counter substrate electrode to a floating state during a period. further comprising a black matrix disposed on the counter substrate,
The in-cell touch panel according to claim 1, wherein the counter substrate electrode is arranged at a position overlapping the black matrix in plan view. further comprising a color filter disposed on the counter substrate,
The in-cell touch panel according to claim 1, wherein the counter substrate electrode is disposed at a position that does not overlap the color filter in plan view. 4. The counter substrate electrode control circuit according to claim 1, wherein the counter substrate electrode control circuit supplies a viewing angle control signal for changing the viewing angle to the counter substrate electrode during a period in which the display mode is executed. In-cell touch panel as described. The counter substrate electrode control circuit includes:
When the viewing angle is set to a narrow viewing angle during the period in which the display mode is being executed, a first viewing angle control signal is supplied to the opposing substrate electrode to control the viewing angle from the opposing substrate electrode. generating a potential difference with the touch sensor electrode;
When the viewing angle is set to a wide viewing angle while the display mode is being executed, a second viewing angle control signal having a smaller amplitude than the first viewing angle control signal is sent to the viewing angle control signal. The in-cell touch panel according to claim 4, wherein the potential difference is supplied to a counter substrate electrode or is made zero. The opposing substrate electrode control circuit superimposes a signal synchronized with the drive signal and having the same polarity as the drive signal on the viewing angle control signal during a period in which the touch detection mode is executed. The in-cell touch panel according to claim 4, wherein the in-cell touch panel is supplied to a substrate electrode . The counter substrate electrode control circuit applies a first base voltage obtained by lowering a predetermined voltage from a viewing angle control signal for changing a viewing angle to the counter substrate electrode while the touch detection mode is being executed. 5 . The in-cell touch panel according to claim 4 , wherein the first base voltage is supplied with a pulsed voltage having the same polarity and the same amplitude as the drive signal and being synchronized with the drive signal to the counter substrate electrode. 6 . The counter substrate electrode control circuit supplies a second base voltage, which is the same as a viewing angle control signal for changing the viewing angle, to the counter substrate electrode during a period in which the touch detection mode is executed; 5. The in-cell touch panel according to claim 4 , wherein a voltage obtained by superimposing a positive polarity pulse voltage in synchronization with the drive signal on the base voltage of No. 2 is supplied to the counter substrate electrode. The counter substrate electrode control circuit includes:
In a period in which the touch detection mode is executed and in a period in which the voltage of the viewing angle control signal for changing the viewing angle has a positive polarity with respect to the voltage of the touch sensor electrode, the viewing angle control signal supplying the same second base voltage to the counter substrate electrode,
During a period in which the touch detection mode is being executed, and during a period in which the voltage of the viewing angle control signal has a negative polarity with respect to the voltage of the touch sensor electrode, the voltage of the viewing angle control signal is changed to the drive signal. 5. The in-cell touch panel according to claim 4 , wherein a third base voltage reduced by the same value as the amplitude of is supplied to the counter substrate electrode.

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