Display device and driving method thereof

Abstract

The invention provides a display device and a driving method thereof. The display device comprises a first electrode, a second electrode, a display medium layer and an electrode driver. The first electrodes serve as touch electrodes. The display medium layer is disposed between the first and second electrodes. The electrode driver is coupled to and drives the first electrode. During a touch sensing period, the electrode driver provides a touch driving signal to the first electrode, and the first electrode performs touch sensing based on the touch driving signal. Moreover, during the touch sensing period, the first average voltage value of the first electrodes is equal to the second average voltage value of the second electrodes.

Description

Technical Field

[0001] The present invention relates to an electro-optical display technology, and in particular to a display device with a touch electrode and a driving method thereof. Background Art

[0002] The term "electro-optic" is primarily used in materials or display related technologies to refer to a material having a first and a second display state. The optical properties of the first and second display states are different from each other, and the material is transformed from the first display state to the second display state, or from the second display state to the first display state by applying an electric field to the material. Although the aforementioned optical property is generally a color that is perceptible to the human eye, it can be other optical properties, such as light transmission, reflection, fluorescence, or false color in the case of a display set up for machine reading. The terms "bistable", "bistable" and "bistable" refer to a display including a display component having a first and a second display state. A specific display component can be given a drive signal of a finite duration to make it present the first or second display state, and the display state of this display component will last at least several times (for example, at least 4 times) the aforementioned finite duration.

[0003] Touch technology has been widely used in various electronic devices, and of course it can also be applied to electro-optical display devices. The display using electrophoretic display technology in the aforementioned electro-optical display device can also be called an electronic paper display (EPD). The previous touch technology is to configure the touch electrode on the electro-optical display panel, but it will make the display device thicker. In order to make the electro-optical display device thinner and lighter, attempts are made to integrate the touch panel with the electro-optical display panel. However, due to signal coupling and material relationships, when performing touch sensing, it will inevitably affect the pixel data in the electro-optical display panel, thereby interfering with the display quality. Summary of the invention

[0004] The present invention is directed to a display device and a driving method thereof, which utilizes one electrode (eg, an upper electrode) of the display device for touch sensing and prevents the touch signal from affecting the voltage of the pixel electrode for the display screen.

[0005] According to an embodiment of the present invention, a display device includes a first electrode, a second electrode, a display medium layer, and an electrode driver. The first electrode serves as a touch electrode. The display medium layer is disposed between the first electrode and the second electrode. The electrode driver couples and drives the first electrode. During touch sensing, the electrode driver provides a touch drive signal to the first electrode, and the first electrode performs touch sensing based on the touch drive signal. Furthermore, during the touch sensing, a first average voltage value of the first electrode is equal to a second average voltage value of the second electrode.

[0006] According to an embodiment of the present invention, a driving method of a display device is applied to a display device. The display device includes a first electrode as a touch electrode, a second electrode and a display medium layer, wherein the display medium layer is arranged between the first electrode and the second electrode. The driving method includes: during touch sensing, providing a touch driving signal to the first electrode, wherein the first electrode performs touch sensing based on the touch driving signal; and making a first average voltage value of the first electrode equal to a second average voltage value of the second electrode.

[0007] Based on the above, the display device and the driving method thereof described in the embodiment of the present invention utilize the first electrode (e.g., the upper electrode) in the display device close to the observer as the touch electrode, and during the touch sensing period, the average voltage value of the first electrode and the second electrode in the display device is set to be the same. In other words, the embodiment of the present invention makes the average voltage difference between the first electrode and the second electrode during the touch sensing period zero. Therefore, the embodiment of the present invention allows the display medium layer to not adjust its display state due to the fluctuation of the DC potential on the first electrode and the second electrode, thereby preventing the touch signal from affecting the voltage of the pixel electrode for the display screen. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of a display device according to an embodiment of the present invention;

[0009] Figure 2 is a circuit structure diagram of a display device according to an embodiment of the present invention;

[0010] Figure 3 is a waveform diagram of each signal in an EPD doze mode in a display device according to an embodiment of the present invention;

[0011] Figure 4 is a waveform diagram of each signal in an EPD active mode in a display device according to an embodiment of the present invention;

[0012] Figure 5 is a flow chart of a driving method of a display device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0013] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals are used in the drawings and the description to refer to the same or like parts.

[0014] When providing a touch drive signal to the touch electrode, the transmission end of the touch electrode will have a DC shift, and the receiving end of the touch electrode will be maintained at a specific DC potential, which is different from the DC potential of the transmission end during sensing. When the touch electrode is integrated into a certain electrode in the display panel (for example, the touch electrode is integrated into the upper electrode), the driving voltage in the display medium layer will be affected by the DC potential and its display state will be changed unexpectedly, thereby affecting the display quality. Therefore, in an embodiment of the present invention, the average voltage value of the first electrode and the second electrode of the display panel during the touch sensing period is set to be the same, so as to avoid the display medium layer, during this touch sensing period, due to the fluctuation of the DC potential on the first electrode and the second electrode, the display state is adjusted, affecting the display quality. The corresponding embodiments consistent with the present invention are presented below for detailed description.

[0015] Figure 1 1 is a schematic diagram of a display device 100-1 according to an embodiment of the present invention. The display device 100-1 mainly includes a first electrode 110, a second electrode 120, a display medium layer 130 and an electrode driver 170. The first electrode 110 of this embodiment serves as a touch electrode. Based on different implementation methods of the circuit structure, the first electrode 110 of this embodiment can be used as a transmission end of the touch electrode (the transmission end of the touch electrode is represented by "Tx" in this embodiment), and the receiving end of the touch electrode can be separately set somewhere in the display device 100-1. The receiving end of the touch electrode is represented by "Rx" in this embodiment. In this embodiment, there can be multiple receiving ends Rx, which are used to determine whether touch sensing occurs in a certain area corresponding to a specific receiving end Rx.

[0016] The receiving end Rx will generate a touch sensing signal based on the touch driving signal on the transmitting end Tx, and the display device 100-1 can perform mutual-capacitive touch sensing based on the touch sensing signal. In another embodiment consistent with the present invention, the first electrode 110 of this embodiment can be used as the transmitting end Tx of the touch electrode, and can also be used as the receiving end Rx of the touch electrode at the same time, and the display device 100 can perform self-capacitive touch sensing based on the touch sensing signal.

[0017] With respect to the observer 105 , the first electrode 110 of the present embodiment may be referred to as a top electrode of the display device 100 , and the second electrode 120 may be referred to as a bottom electrode of the display device 100 . Figure 1 The observer 105 is used to indicate the sight line position of the user with respect to the display device 100 .

[0018] The display medium layer 130 is disposed between the first electrode 110 and the second electrode 120. In other words, the display medium layer 130 is disposed between the first electrode 110 and the active device matrix substrate 160. The active device matrix substrate 160 will be Figure 2 Detailed description: The display medium layer 130 of this embodiment is suitable for the display medium area in the electronic paper technology, and the display medium layer 130 can be an electrophoretic electronic ink layer with microencapsulation. The electrophoretic electronic ink has a bistable display function.

[0019] The electrode driver 170 is coupled to and drives the first electrode 110 and the second electrode 120. The electrode driver 170 of this embodiment is used to provide corresponding signals to the first electrode 110 and the second electrode 120. The user of this embodiment can design the circuit structure of the electrode driver 170 according to their needs. For example, the electrode driver 170 can be implemented by using two different voltage suppliers, one of which is dedicated to providing signals to the first electrode 110, and the other voltage supplier is dedicated to providing signals to the second electrode 120.

[0020] During the touch sensing period, the electrode driver 170 of this embodiment provides a touch driving signal to the first electrode 110, and the first electrode 110 performs touch sensing based on the touch driving signal. Moreover, during the touch sensing period, the first average voltage value of the first electrode 110 is equal to the second average voltage value of the second electrode 120. The detailed description of the electrode driver 170 and the touch driving signal can be found in the following embodiments.

[0021] The display device 100-1 may further include a front substrate 140, a backplane 150, and an active device matrix substrate 160. The front substrate 140 is disposed close to the observer 105, and in some embodiments, a color filter array may be formed on the front substrate 140 to adjust the color presented by the display medium layer 130. The active device matrix substrate 160 may be formed on the backplane 150.

[0022] Figure 2 is a circuit structure diagram of a display device 100 - 2 according to an embodiment of the present invention. Figure 2 The main components of the active element matrix substrate 160 and related circuit components in the display device 100-2 are presented. Figure 1 The display device 100-1 mainly presents a cross-sectional structure to complement each other. In other words, those who apply this embodiment can know that Figure 1 The display device 100-1 and Figure 2 The display device 100 - 2 is the same.

[0023] refer to Figure 2 , Figure 2 The display device 100-2 has Figure 1 In addition to the components shown, the driving circuit 180 and the components in the active element matrix substrate 160 are also included. The active element matrix substrate 160 of the display device 100-2 includes a scan line GL, a data line DL, a transistor MT, a pixel electrode PE and a second electrode 120. The transistor MT includes a gate terminal G and a source terminal S. The gate terminal G is electrically connected to the corresponding scan line GL, and the source terminal S is electrically connected to the corresponding data line DL.

[0024] The driving circuit 180 includes a timing controller 182, a gate driver 184 and a source driver 186. The driving circuit 180 provides a voltage to the pixel electrode PE for displaying the image through the scan line GL and the data line DL. Figure 1 The display medium layer 130 is disposed between the first electrode 110 and the second electrode 120. A storage capacitor C2 is formed between the first electrode 110 and the pixel electrode PE. A display medium capacitor C2 is provided between the second electrode 120 and the pixel electrode PE. This embodiment utilizes the storage capacitor C2, the display medium capacitor C1, and the component characteristics in the display medium layer 130 to adjust the display state of each pixel, thereby adjusting the display image.

[0025] According to the control mode, the display device of this embodiment includes an electronic paper display (EPD) active mode and an EPD snooze mode. Figure 3 As shown, the EPD doze mode 310 means that the display device does not change the display screen, but still has the touch function, so the EPD doze mode 310 has a touch sensing period 314 and a maintenance period 312. On the other hand, the EPD active mode 320 means that the display device is changing the display screen and has the touch function at the same time, so the EPD active mode 320 has a display adjustment period 326 in addition to the touch sensing period 324 and the maintenance period 322. Figure 4 As an example. Figure 3 and Figure 4 All of them take mutual capacitance touch sensing as an example, that is, the first electrode 110 is used as the transmission end Tx of the touch electrode, and the receiving end Rx of the touch electrode is set separately.

[0026] Figure 3 3 is a waveform diagram of various signals in an EPD doze mode 310 in a display device according to an embodiment of the present invention. Figure 3 , Figure 3The upper part of the graph shows the waveforms of the first electrode 110 and the second electrode 120 in the EPD doze mode 310 and the EPD active mode 320, respectively. A portion of the waveform 311 in the EPD doze mode 310 is enlarged and shown in FIG. Figure 3 The lower part of .

[0027] Figure 3 The lower part of FIG. 3 shows a portion of a waveform 311 in the EPD doze mode 310, and the portion of the waveform 311 includes a maintenance period 312 and a touch sensing period 314 that are performed alternately. The maintenance period 312 and the touch sensing period 314 do not overlap each other on the time axis.

[0028] During the touch sensing period 314, Figure 1 The electrode driver 170 provides a touch driving signal TSS to the transmission terminal Tx of the first electrode 110. The first electrode 110 performs touch sensing based on the touch driving signal TSS. In addition, during the touch sensing period 314, the first average voltage value (e.g., Figure 3 0V) is equal to the second average voltage value of the second electrode 120 (eg Figure 3 The average voltage value of the receiving end Rx in the first electrode 110 is also equal to the first predetermined potential (0V).

[0029] In another embodiment of the present invention, the first predetermined potential can be set to other potentials, not limited to 0 V. For example, the user of this embodiment can select any potential from 0 V to 2.5 V as the first predetermined potential according to the requirements.

[0030] In another embodiment of the present invention, the average voltage value of the receiving end Rx in the first electrode 110 is not necessarily equal to the aforementioned first predetermined potential (0V), but can also be another DC potential (eg, any potential between 0V and 2.5V), and this other DC potential is different from the first predetermined potential.

[0031] from Figure 3 It can be seen that although the voltage waveform on the transmission terminal Tx during the touch sensing period 314 includes the touch driving signal TSS, the average voltage value (0V) on the transmission terminal Tx during the touch sensing period 314 is equal to the average voltage value (0V) of the second electrode 120. That is, the average voltage difference between the first electrode 110 and the second electrode 120 during the touch sensing period 314 is zero. In this embodiment, the average voltage value (0V) on the transmission terminal Tx during the touch sensing period 314 is also equal to the average voltage value (0V) on the receiving terminal Rx.

[0032] During the touch sensing period 314 , the gate terminal G and the source terminal S of the transistor may be in a high impedance state Hi-Z. Alternatively, the gate terminal G and the source terminal S of the transistor may be maintained at a first predetermined potential (0V).

[0033] On the other hand, during the maintaining period 312 , the transmission end Tx, the reception end Rx of the first electrode 110 and the second electrode 120 are all maintained at the second predetermined potential. Figure 3 The second predetermined potential is set to 0V. The source terminal G and the gate terminal S of the transistor are in a high impedance state Hi-Z. Alternatively, the gate terminal G and the source terminal S of the transistor can be maintained at the second predetermined potential (0V). Figure 3 The first predetermined potential and the second predetermined potential may be the same, or the two potentials may be adjusted to be different according to the needs of the user of this embodiment.

[0034] Since the corresponding potentials in the source terminal and the gate terminal of the transistor are in a high impedance state (eg, Figure 3 ), or the DC potentials of the source terminal and the gate terminal are the same as the predetermined DC potential (eg, 0V). In this way, the data of each pixel in the display medium layer will be maintained without being affected by the touch driving signal in the first electrode.

[0035] Figure 4 3 is a waveform diagram of various signals in an EPD active mode 320 in a display device according to an embodiment of the present invention. Figure 3 , Figure 3 The upper part of the graph shows the waveforms of the first electrode 110 and the second electrode 120 in the EPD doze mode 310 and the EPD active mode 320, respectively. A portion of the waveform 321 in the EPD active mode 320 is magnified and shown in FIG. Figure 4 The lower part of .

[0036] Figure 4 The lower part of 320 shows a portion of waveform 321 in the EPD doze mode 320, and the portion of waveform 321 includes a display adjustment period 326, a touch sensing period 324, and a maintenance period 322. The display adjustment period 326, the touch sensing period 324, and the maintenance period 322 do not overlap each other on the time axis.

[0037] During the touch sensing period 324, Figure 1The electrode driver 170 provides a touch driving signal TSS to the transmission end Tx of the first electrode 110, and the first electrode 110 performs touch sensing based on the touch driving signal TSS. Moreover, during the touch sensing period 314, the first average voltage value (0V) of the transmission end Tx in the first electrode 110 is equal to the second average voltage value (0V) of the second electrode 120, that is, equal to the first predetermined potential (0V). The average voltage value of the receiving end Rx in the first electrode 110 is also equal to the first predetermined potential (0V). In another embodiment of the present invention, the average voltage value of the receiving end Rx in the first electrode 110 is not necessarily equal to the aforementioned first predetermined potential (0V), but may also be another DC potential (e.g., any potential between 0V and 2.5V), and this other DC potential is different from the first predetermined potential.

[0038] from Figure 4 It can be seen that although the voltage waveform on the transmission terminal Tx during the touch sensing period 324 includes the touch driving signal TSS, the average voltage value (0V) on the transmission terminal Tx during the touch sensing period 314 is equal to the average voltage value (0V) of the second electrode 120, and even equal to the average voltage value (0V) on the receiving terminal Rx. That is, the average voltage difference between the first electrode 110 and the second electrode 120 during the touch sensing period 314 is zero.

[0039] exist Figure 4 During the touch sensing period 324, the gate terminal G and the source terminal S of the transistor may be maintained at a first predetermined potential (0V). Alternatively, the gate terminal G and the source terminal S of the transistor may be in a high impedance state Hi-Z.

[0040] During the maintaining period 322 , the transmission end Tx, the reception end Rx of the first electrode 110 and the second electrode 120 are all maintained at the second predetermined potential. Figure 4 The second predetermined potential is set to -1V. The user of this embodiment can set the second predetermined potential to any potential between -1V and -3V according to his / her needs. The source terminal G and the gate terminal S of the transistor can be the aforementioned second predetermined potential (such as Figure 4 presented).

[0041] During the display adjustment period 326, the DC potential of the transmission terminal Tx, the receiving terminal Rx of the first electrode and the second electrode 120 is maintained at the second predetermined potential (-1V). The gate terminal G of the transistor is provided with a scan signal SS, and the source terminal S is provided with a data signal DS to adjust the display state of each pixel, thereby adjusting the display image.

[0042] Since the corresponding potentials at the source terminal and the gate terminal of the transistor are in a high impedance state or the same as the aforementioned second predetermined DC potential (-1V) during the touch sensing period 324 and the maintenance period 322 (eg, Figure 4As shown in FIG. 1 , the data of each pixel in the display medium layer will be maintained during the touch sensing period 324 and the maintaining period 322 , and will not be affected by the touch driving signal TSS.

[0043] Figure 5 is a flow chart of a method for driving a display device according to an embodiment of the present invention. The driving method is applicable to Figure 1 and Figure 2 The display device 100-1, 100-2 includes a first electrode 110 as a touch electrode, a second electrode 120 and a display medium layer 130, and the display medium layer 130 is disposed between the first electrode 110 and the second electrode 120. Figure 1 , Figure 2 and Figure 5 In step S510, during the touch sensing period, the electrode driver 170 provides a touch driving signal to the first electrode 110, and the first electrode 110 performs touch sensing based on the touch driving signal. In step S520, the electrode driver 170 makes the first average voltage value of the first electrode 110 equal to the second average voltage value of the second electrode 120.

[0044] In step S530, during the maintenance period which is not the touch sensing period, the electrode driver 170 maintains the DC potential of the first electrode 110, the second electrode 120 and the plurality of receiving terminals Rx at a second predetermined potential. In step S540, the source terminal S and the gate terminal G of the transistor are maintained at the second predetermined potential, or the source terminal S and the gate terminal G of the transistor are in a high impedance state.

[0045] In step S550, during the display adjustment period which is not the touch sensing period and the maintenance period, the electrode driver 170 maintains the DC potential of the first electrode 110, the second electrode 120 and the plurality of receiving terminals Rx at a second predetermined potential. In step S560, a scan signal is provided to the gate terminal G of the transistor. In step S570, a data signal is provided to the source terminal S of the transistor. For the detailed process and operation of steps S510 to S570, please refer to the above embodiments.

[0046] In summary, the display device and the driving method thereof described in the embodiment of the present invention utilize the first electrode (e.g., the upper electrode) in the display device close to the observer as the touch electrode, and during the touch sensing period, the average voltage values ​​of the first electrode and the second electrode in the display device are set to be the same. In other words, the embodiment of the present invention makes the average voltage difference between the first electrode and the second electrode during the touch sensing period zero. Therefore, the embodiment of the present invention allows the display medium layer to not adjust its display state due to the fluctuation of the DC potential on the first electrode and the second electrode, thereby preventing the touch signal from affecting the voltage of the pixel electrode for the display screen.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A display device, characterized in that: include: A first electrode, serving as a touch electrode; a second electrode; A display medium layer, disposed between the first electrode and the second electrode; as well as an electrode driver, coupled to and driving the first electrode, During the touch sensing period, the electrode driver provides a touch driving signal to the first electrode, and the first electrode performs touch sensing based on the touch driving signal. Furthermore, during the touch sensing period, a first average voltage value of the first electrode is equal to a second average voltage value of the second electrode.

2. The display device according to claim 1, characterized in that Also includes: An active element matrix substrate, the active element matrix substrate comprising: Scan line; Data cable; A transistor, the transistor comprising a gate terminal and a source terminal, the gate terminal is electrically connected to the corresponding scan line, and the source terminal is electrically connected to the corresponding data line; a pixel electrode electrically connected to the transistor; and The second electrode forms a storage capacitor with the pixel electrode, The display medium layer is arranged between the first electrode and the active element matrix substrate.

3. The display device according to claim 2, characterized in that: Also includes: A driving circuit is coupled to the scan line and the data line, The driving circuit provides the pixel electrode with a voltage for displaying a picture through the scanning line and the data line.

4. The display device according to claim 1, characterized in that The potential of the second electrode is maintained at the second average voltage value during the touch sensing period.

5. The display device according to claim 2, characterized in that: The first average voltage value and the second average voltage value during the touch sensing period are a first predetermined potential, the source terminal and the gate terminal of the transistor are maintained at the first predetermined potential, or the source terminal and the gate terminal of the transistor are in a high impedance state; During a maintenance period other than the touch sensing period, the DC potentials of the first electrode, the second electrode and a plurality of receiving ends are maintained at a second predetermined potential; During the maintaining period, the source terminal and the gate terminal of the transistor are maintained at the second predetermined potential, or the source terminal and the gate terminal of the transistor are in a high impedance state.

6. The display device according to claim 5, characterized in that: During a display adjustment period that is neither the touch sensing period nor the maintenance period, the DC potentials of the first electrode, the second electrode and the multiple receiving ends are maintained at the second predetermined potential, the gate end of the transistor is provided with a scan signal, and the source end is provided with a data signal.

7. A method for driving a display device, wherein the display device comprises a first electrode as a touch electrode, a second electrode and a display medium layer, wherein the display medium layer is arranged between the first electrode and the second electrode, characterized in that: The driving method comprises: During a touch sensing period, providing a touch driving signal to the first electrode, and the first electrode performs touch sensing based on the touch driving signal; and A first average voltage value of the first electrode is made equal to a second average voltage value of the second electrode.

8. The driving method according to claim 7, characterized in that: The display device further includes an active element matrix substrate, wherein the active element matrix substrate includes a scan line, a data line, a transistor, a pixel electrode and the second electrode. The transistor includes a gate terminal and a source terminal, the gate terminal is electrically connected to the corresponding scan line, and the source terminal is electrically connected to the corresponding data line. The pixel electrode is electrically connected to the transistor, and the second electrode and the pixel electrode form a storage capacitor. The display medium layer is arranged between the first electrode and the active element matrix substrate.

9. The driving method according to claim 8, characterized in that: The first average voltage value and the second average voltage value during the touch sensing period are a first predetermined potential, the source terminal and the gate terminal of the transistor are maintained at the first predetermined potential, or the source terminal and the gate terminal of the transistor are in a high impedance state, Furthermore, the driving method further comprises: During a maintenance period other than the touch sensing period, the DC potentials of the first electrode, the second electrode and a plurality of receiving ends are maintained at a second predetermined potential; and During the maintaining period, the source terminal and the gate terminal of the transistor are maintained at the second predetermined potential, or the source terminal and the gate terminal of the transistor are in a high impedance state.

10. The driving method according to claim 9, characterized in that: Also includes: During a display adjustment period that is neither the touch sensing period nor the maintenance period, the DC potentials of the first electrode, the second electrode, and the plurality of receiving ends are maintained at the second predetermined potential; providing a scan signal to the gate terminal of the transistor; as well as A data signal is provided to the source terminal of the transistor.

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