Since the display light transmitting area DA_T further includes the light transmitting portion compared to the display dedicated area DA_D, the display light transmitting area DA_T and the display dedicated area DA_D may have different densities of pixels PX related to resolution. For example, the resolution of the display light transmitting area DA_T may be lower than the resolution of the display dedicated area DA_D, but is not necessarily limited thereto.

FIG. 3 is a conceptual view of a display unit and a touch driver according to an embodiment.

Referring to FIG. 3, the display device 10 includes a display panel 100 including a plurality of pixels PX, a display driving circuit 200, and a touch driving circuit 400. The display driving circuit 200 and the touch driving circuit 400 may operate based on a control signal or command signal from a host 11. For example, the host 11 may be an application processor (or another form of processor circuit). According to an embodiment, the touch driving circuit 400 may be controlled by the display driving circuit 200.

The display driving circuit 200 may include a data driver 230 and a display control unit 220.

The display control unit 220 may receive input data (R, G, B) and a timing control signal from the outside (e.g., the host 11). The timing control signal may include a vertical synchronization signal Vsync indicating one frame period, a horizontal synchronization signal Hsync indicating one horizontal period, and a main clock MCLK that repeats at a predetermined period. The input data (R, G, B) may be RGB data including red image data, green image data, and blue image data. The display control unit 220 may generate output data signals DR, DG, and DB and an internal control signal using the received input data (R, G, B) and timing control signal. The internal control signal includes a data control signal DCS and a gate control signal GCS.

The vertical synchronization signal Vsync may serve as a noise level signal indicating a noise level of the display panel 100, as will be described later with reference to FIG. 9. For example, the host 11 predetermines the noise level of the display panel 100, varies the vertical synchronization signal Vsync according to the determined noise level of the display panel 100, and supplies the varied vertical synchronization signal Vsync to the display control unit 220 or the touch driving circuit 400.

As used herein, a high noise level of the display panel 100 means that a noise influence from the display panel 100 to a touch sensor TSM is relatively large. As used herein, a low noise level of the display panel 100 means that a noise influence from the display panel 100 to the touch sensor TSM is relatively small.

The host 11 may analyze image data to be displayed on the display panel 100 and predetermine the noise level of the display panel 100. The host 11 may be configured to determine whether a screen according to the image data is a specific screen and determine the noise level according to the determined result. The specific screen may include, for example, an image with repeated white and black areas (e.g., a zebra image) or an always on display (AOD) image, but the type of the specific screen is not necessarily limited thereto.

The host 11 may be configured to determine a state of a mobile electronic device to which the display device 10 is applied, for example, whether an electrical charger (e.g., travel adapter) is connected to the mobile electronic device, and determine the noise level according to the determined result.

The host 11 may supply a separate noise level signal indicating the noise level to the display control unit 220 or the touch driving circuit 400 without using the horizontal synchronization signal Hsync. However, in the following, it will be mainly described that the horizontal synchronization signal Hsync serves as a noise level signal.

The display control unit 220 may control an operation of the data driver 230 by providing a data control signal DCS to the data driver 230. The display control unit 220 may control an operation of the gate driver 210 by providing a gate control signal GCS to the gate driver 210.

The data driver 230 may receive the output data signals DR, DG, and DB and the data control signal DCS from the display control unit 220. The data driver 230 may generate a data signal using the received output data signals DR, DG, and DB and data control signal DCS. The data driver 230 may provide the generated data signal to the display panel 100. The data driver 230 may provide the data signal to the plurality of pixels PX through a plurality of data lines DL formed in the display panel 100.

The gate driver 210 may receive the gate control signal GCS from the display control unit 220. The gate driver 210 may generate a gate signal using the received gate control signal GCS. The gate driver 210 may provide the generated gate signal to the display panel 100. The gate driver 210 may provide the gate signal to the plurality of pixels PX through a plurality of gate lines SL formed in the display panel 100.

It is illustrated in FIG. 3 that the display driving circuit 200 does not include the gate driver 210, but the present disclosure is not necessarily limited thereto. For example, the gate driver 210 may be included in the display driving circuit 200 that controls the operation of the display panel 100. The gate driver 210, the data driver 230, and the display control unit 220 may be formed as an integrated circuit (IC). The gate driver 210 may be formed during a TFT process of the display panel 100. The display control unit 220 and the data driver 230 may be merged to form a timing controller embedded driver integrated circuit (TED).

The display panel 100 may include a plurality of pixels PX connected to the plurality of data lines DL and the plurality of gate lines SL.

A frame frequency at which the display driving circuit 200 drives the display panel 100 may be variable. For example, the frame frequency may vary within the range of 1 Hz to 240 Hz depending on the selection of the host 11 or the user. The display driving circuit 200 may drive at 60 Hz for one period and change the frame frequency to 120 Hz for another period depending on the user's needs.

The touch sensing area SA may include a plurality of first electrodes (120 in FIG. 5), a plurality of second electrodes (130 in FIG. 5), and a plurality of touch driving lines and touch sensing lines. The touch sensing area SA may sense a touch input by being applied with an electrical signal from the touch driving circuit 400 disposed on the circuit board 300 through the plurality of touch driving lines, or transmitting the electrical signal sensed from the plurality of first electrodes 120 to the touch driving circuit 400 through the plurality of touch sensing lines. For example, the touch driving circuit 400 may sense the touch input by converting an analog electrical signal sensed in the touch sensing area SA into a digital signal.

FIG. 4 schematically illustrates a touch sensor TSM and a display device including the same according to an embodiment. FIG. 5 is a block diagram of the touch sensor TSM according to an embodiment illustrated in FIG. 4.

Referring to FIGS. 4 and 5, the display device 10, according to an embodiment, may include a touch sensor TSM and a display panel 100, and may further include a display driving circuit 200. The touch sensor TSM includes a sensor unit 410 and a touch driving circuit 400.

It is illustrated in the illustrated embodiment that the sensor unit 410 and the display panel 100 are separated from each other, but this is for convenience of explanation, and the present disclosure is not necessarily limited thereto. For example, the sensor unit 410 and the display panel 100 may also be integrally formed.

The display panel 100 may include a display area DA and a non-display area NDA at least partially surrounding at least one area of the display area DA. The display area DA is provided with a plurality of gate lines SL and data lines DL, and a plurality of pixels P (e.g., PX in FIG. 3) connected to the gate lines SL and data lines DL. The non-display area NDA may be provided with lines for supplying various driving signals and/or driving power for driving the pixels P.

In the present disclosure, the type of display panel 100 is not necessarily particularly limited thereto. For example, the display panel 100 may be a self-light emitting display panel such as an organic light emitting diode (OLED) display panel, a quantum dot light emitting display (QLED) panel, a micro light emitting diode (LED) display panel, and a nano light emitting diode (LED) display panel. Alternatively, the display panel 100 may be a non-light emitting display panel such as a liquid crystal display (LCD) panel, an electro-phoretic display (EPD) panel, and an electro-wetting display (EWD) panel. When the display panel 100 is a non-light emitting display panel, the display device may further include a back-light unit for supplying light to the display panel 100. Hereinafter, for convenience of description, a case in which the display panel 100 is an organic light emitting diode (OLED) display panel will be described as an example.

The sensor unit 410 may be provided on at least one area of the display panel 100. For example, the sensor unit 410 may be provided on at least one surface of the display panel 100 to overlap the display panel 100. For example, the sensor unit 410 may be disposed on one (e.g., an upper surface) of both surfaces of the display panel 100 in a direction in which the image is emitted. Alternatively, the sensor unit 410 may be formed directly on at least one of both surfaces of the display panel 100, or may be formed inside the display panel 100. For example, the sensor unit 410 may be formed directly on an outer surface (e.g., an upper surface of an upper substrate or a lower surface of a lower substrate) of the upper substrate (or thin film encapsulation layer) or the lower substrate of the display panel 100, or may also be formed directly on an inner surface (e.g., a lower surface of the upper substrate or an upper surface of the lower substrate) of the upper or lower substrate.

The sensor unit 410 includes a sensing area SA and a peripheral area NSA. In some embodiments, the peripheral area NSA may at least partially surround at least a portion of the sensing area SA. In some embodiments, the sensing area SA may be an area of the sensor unit 410 that senses a touch input, and the peripheral area NSA may be an area of the sensor unit 410 that does not sense a touch input. According to the embodiment, the sensing area SA may be disposed to correspond to the display area DA of the display panel 100, and the peripheral area NSA may be disposed to correspond to the non-display area NDA of the display panel 100. For example, the sensing area SA of the sensor unit 410 may overlap the display area DA of the display panel 100, and the peripheral area NSA of the sensor unit 410 may overlap the non-display area NDA of the display panel 100.

A plurality of first touch electrode members 120 and a plurality of second touch electrode members 130 for detecting a touch input may be provided in the sensing area SA of the sensor unit 410. The first touch electrode member 120 may be called “touch sensing electrode 120” or “first electrode.” The second touch electrode member 130 may be called “touch driving electrode 130” or “second electrode.” Hereinafter, in some descriptions, the description will be made by replacing the first touch electrode member 120 with the touch sensing electrode 120. Hereinafter, in some descriptions, the description will be made by replacing the second touch electrode member 130 with the touch driving electrode 130.

The first touch electrode members 120 may extend along a first direction (e.g., x-direction) and may be spaced apart from each other along a second direction (e.g., y-direction) that intersects the first direction x. For example, the first touch electrode members 120 extending in the first direction x may be spaced apart from each other along the second direction y to form an electrode row.

The second touch electrode members 130 may extend along the second direction y and be spaced apart from each other along the first direction x. The second touch electrode member 130 may be spaced apart from the first touch electrode member 120 and may be insulated from the first touch electrode member 120. For example, the second touch electrode members 130 extending in the second direction y may be spaced apart from each other along the first direction x to form a column.

The shape, size, and/or arrangement direction of the first touch electrode member 120 and the second touch electrode member 130 are not necessarily particularly limited thereto.

The first touch electrode member 120 and the second touch electrode member 130 may be electrically connected to the touch driving circuit 400. In some embodiments, the second touch electrode member 130 may be a driving electrode member that receives a driving signal Ts for touch detection from the touch driving circuit 400, and the first touch electrode member 120 may be a sensing electrode member that outputs a sensing signal Rs for touch detection to the touch driving circuit 400.

The first touch electrode member 120 and the second touch electrode member 130 may overlap at least one electrode provided in the display panel 100. For example, when the display panel 100 is an organic light emitting diode (OLED) display panel, the first touch electrode member 120 and the second touch electrode member 130 may overlap a cathode electrode of the display panel 100, etc.

A conductive member 150 may be provided in the sensing area SA of the sensor unit 410. The conductive member 150 may sense noise generated in the sensor unit 410 and provide the sensed noise as a noise signal Ns to a touch detector 570. The conductive member 150 may be spaced apart from the first touch electrode member 120 and the second touch electrode member 130 and may be insulated from the first touch electrode member 120 and the second touch electrode member 130. The conductive member 150 may be called “noise sensing electrode 150” or “third electrode.” Hereinafter, in some descriptions, the description will be made by replacing the conductive member 150 with the noise sensing electrode 150.

In some embodiments, the conductive members 150 may extend along the first direction x in the same manner as the first touch electrode members 120 and may be spaced apart from each other along the second direction y that intersects the first direction x.

The touch driving circuit 400 may detect a touch position by being electrically connected to the sensor unit 410 to supply the driving signal Ts to the sensor unit 410 and receive the sensing signal Rs corresponding to the driving signal Ts from the sensor unit 410.

In some embodiments, the touch driving circuit 400 may include a touch driver 510 and a touch detector 570. In addition, the touch driving circuit 400 may further include an amplifying circuit 530.

The touch driver 510 may provide a driving signal Ts for detecting a touch input to the second touch electrode member 130.

The touch detector 570 may detect the presence or absence of the touch input and/or a position of the touch input by receiving the sensing signal Rs corresponding to the driving signal Ts from the first touch electrode member 120 during a period of performing the touch sensing operation. In some embodiments, the sensing signal Rs may be an amount of change in mutual capacitance occurring between the first touch electrode member 120 and the second touch electrode member 130. For example, when the touch input occurs, mutual capacitance changes at a point where the touch input is provided or a peripheral portion of the point. The touch detector 570 may receive the amount of change in mutual capacitance between the first touch electrode member 120 and the second touch electrode member 130 as the sensing signal Rs, and may be configured to determine the presence or absence of the touch input and the position of the touch input using the sensing signal Rs. In addition, the touch detector 570 may receive the noise signal Ns from the conductive member 150 and remove or cancel out noise included in the sensing signal Rs using the noise signal Ns. Removing or canceling out the noise included in the sensing signal Rs using the noise signal Ns may mean compensating for the sensing signal Rs using the noise signal Ns.

In some embodiments, the touch detector 570 may include one or more amplifiers that amplify the received sensing signal Rs, an analog digital converter connected to an output terminal of the amplifier, and a processor.

The amplifying circuit 530 may be connected to the conductive member 150 and the touch detector 570, and may amplify the noise signal Ns provided from the conductive member 150 or adjust a gain value and provide the amplified noise signal Ns or adjusted gain value to the touch detector 570.

In some embodiments, the touch driver 510, the touch detector 570, and the amplifying circuit 530 may be integrated inside one touch IC. However, the present disclosure is not necessarily limited thereto. In some other embodiments, portions of the touch driver 510, touch detector 570, and amplifying circuit 530 may be positioned inside the touch IC, and other portions of the touch driver 510, touch detection unit 570, and amplification circuit 530 may also be positioned elsewhere than inside the touch IC.

FIG. 6 is a view for schematically describing a touch position detection operation of the touch sensor TSM according to an embodiment. FIG. 7 is a view illustrating a connection relationship between a sensor unit and a control unit according to an embodiment.

Referring to FIGS. 6 and 7, the touch driver 510 may provide the driving signal Ts to the second touch electrode member 130 through a first touch signal line 901 and a second touch signal line 903. In some embodiments, the driving signal Ts may be sequentially provided to each of the second touch electrode members 130.

The touch detector 570 may receive the sensing signal Rs from the first touch electrode member 120 through a third touch signal line 905.

In some embodiments, the sensing signal Rs may include information on the amount of change in mutual capacitance occurring between the first touch electrode member 120 and the second touch electrode member 130 as described above. When the driving signal Ts is provided to the second touch electrode member 130, a mutual capacitance Cm is formed between the second touch electrode member 130 and the first touch electrode member 120. In addition, when a touch event such as a touch input occurs, a change in mutual capacitance Cm may occur. The first touch electrode member 120 may output the sensing signal Rs corresponding to the driving signal Ts, and the sensing signal Rs output by the first touch electrode member 120 may be input to the touch detector 570. In some embodiments, the sensing signal Rs may include the information on the amount of change in mutual capacitance described above.

In some embodiments, the touch detector 570 may include a plurality of sensing channels SC electrically connected to each first touch electrode member 120. In addition, the touch detector 570 may include at least one analog digital converter (ADC) 573 connected to the sensing channel SC and a processor 575. Hereinafter, the sensing channel SC and the analog digital converter 573 will be described as separate components, but in another embodiment, the analog digital converter 573 may also be configured within each sensing channel SC.

The sensing channel SC may receive the sensing signal Rs from each first touch electrode member 120, and amplify and output the received sensing signal Rs. In some embodiments, the sensing channel SC may include an analog front end including at least one amplifier 571, such as an operational (OP) amplifier.

The amplifier 571 may include a first input terminal 5711, a second input terminal 5713, and an output terminal 5715. Depending on the embodiment, the first input terminal 5711 of the amplifier 571, for example, an inverting input terminal of the OP amplifier, may be electrically connected to the first touch electrode member 120 through a third touch signal line 905, etc., and the sensing signal Rs may be input to the first input terminal 5711.

In some embodiments, the second input terminal 5713 of the amplifier 571, for example, a non-inverting input terminal of the OP amplifier, may be electrically connected to the conductive member 150 or the amplifying circuit 530 through a noise signal line 907, etc., and the noise signal Ns output from the conductive member 150 may be provided to the second input terminal 5713 of the amplifier 571. Accordingly, a reference voltage of each amplifier 571 changes together depending on a voltage change of each conductive member 150. For example, a reference potential of each amplifier 571 may change depending on a potential (e.g., voltage level) of the conductive member 150.

The potential of the conductive member 150 may change depending on the noise signal Ns flowing into the sensor unit 410 from the display panel 100, etc. For example, the potential of the conductive member 150 may change in response to noise flowing into the sensor unit 410 from the display panel 100, etc.

When the conductive member 150 is further disposed in the sensing area SA and the reference potential of the amplifier 571 is changed using the noise signal Ns output from the conductive member 150, the noise flowing into the sensor unit 410 may be canceled out (or removed).

For example, the first touch electrode member 120, which is the sensing electrode member, and the conductive member 150 have ripples corresponding to each other in response to noise. In particular, as the first touch electrode member 120 and the conductive member 150 extend in the same direction and are arranged at positions corresponding to each other, the first touch electrode member 120 and the conductive member 150 receive noise signals of the same or very similar shape and/or magnitude. In addition, the first touch electrode member 120 is electrically connected to the first input terminal 5711 of the amplifier 571 through the third touch signal line 905, and the conductive member 150 is electrically connected to the second input terminal 5713 of the amplifier 571 through the noise signal line 907 that is different from the third touch signal line 905. For example, the noise signal Ns is provided to the amplifier 571 through a different path from the sensing signal Rs. Therefore, a noise component (e.g., ripple) included in the sensing signal Rs received from the first touch electrode member 120 may be effectively canceled out. Accordingly, the signal output from the output terminal 5715 of the amplifier 571 may be a sensing signal from which the noise is removed.

In some embodiments, the sensing channel SC may further include a capacitor C and a reset switch SW connected in parallel between the first input terminal 5711 and the output terminal 5715 of the amplifier 571.

It is described in the above-described example that the amplifier 571 is implemented in the form of an inverting amplifier, but the present disclosure is not necessarily limited thereto. In another embodiment, the amplifier 571 may also be implemented in the form of a non-inverting amplifier.

The output terminal 5715 of the amplifier 571 may be electrically connected to the analog digital converter 573.

The analog digital converter 573 may convert the input analog signal into a digital signal. Depending on the embodiment, the analog digital converter 573 may be provided as many as the number of first touch electrode members 120 to correspond to each first touch electrode member 120 in a one-to-one manner. Alternatively, in another embodiment, each first touch electrode member 120 may be configured to share one analog digital converter 573, and in this case, a separate switch circuit for selecting the sensing channel may be further provided.

The processor 575 performs signal processing on the converted signal (e.g., digital signal) from the analog digital converter 573 and detects the touch input according to the signal processing result. As an example, the processor 575 may detect whether the touch input occurs and a position of the touch input by comprehensively analyzing the first sensing signal amplified by the amplifier 571 and converted by the analog digital converter 573. Depending on the embodiment, the processor 575 may be implemented as a microprocessor (MPU). In this case, a memory necessary for driving the processor 575 may be additionally provided inside the touch detector 570. The configuration of the processor 575 is not necessarily limited thereto. As another example, the processor 575 may also be implemented as a microcontroller (MCU).

The touch driving circuit 400 may further include an amplifying circuit 530 connected between the second input terminal 5713 of the sensing channel SC and the conductive member 150. Depending on the embodiment, the amplifying circuit 530 may include at least one amplifier 231. Depending on the embodiment, the amplifier 231 may include a first input terminal 2311 commonly connected to the conductive member 150 through the noise signal line 907, and a second input terminal 2313 connected to an output terminal 2315 through at least one resistance Ra. Depending on the embodiment, the first input terminal 2311 and the second input terminal 2313 may be an inverting input terminal and a non-inverting input terminal, respectively, but are not necessarily limited thereto. For reference, Ra and Rb in FIG. 7 illustrate input and output impedances of the amplifier 231.

This amplifying circuit 530 may receive the noise signal Ns output from the conductive member 150, amplify the noise signal Ns to a degree corresponding to the gain value of the amplifier 231, and output the amplified noise signal Ns to each sensing channel SC. In this case, by adjusting the gain value of the amplifying circuit 530, the magnitude of the noise signal Ns input to the sensing channel SC may be easily adjusted. In some embodiments, the gain value of the amplifying circuit 530 may be adjusted so that the noise component included in the sensing signal Rs output from the first touch electrode member 120 may be effectively canceled inside the sensing channel SC.

Depending on the embodiment, the amplifying circuit 530 may further include a plurality of variable resistors VR1, VR2, VR3, and VR4 connected in parallel between the output terminal 2315 of the amplifier 231 and a predetermined reference power supply GND, such as a ground power supply. As an example, the amplifying circuit 530 may include a number of variable resistors VR1, VR2, VR3, and VR4 corresponding to the number of sensing channels SC.

Depending on the embodiment, each sensing channel SC may be connected to a different variable resistor among the variable resistors VR1, VR2, VR3, and VR4 provided in the amplifying circuit 530. For example, based on FIG. 7, the second input terminal 5713 of the first sensing channel SC corresponding to a fourth electrode row RE4 may be connected to a first variable resistor VR1, and the second input terminal 5713 of the second sensing channel SC corresponding to a third electrode row RE3 may be connected to a second variable resistor VR2. In addition, the second input terminal 5713 of the third sensing channel SC corresponding to a second electrode row RE2 may be connected to a third variable resistor VR3, and the second input terminal 5713 of the fourth sensing channel SC corresponding to a first electrode row RE1 may be connected to a fourth variable resistor VR4.

FIG. 8 is a conceptual view schematically illustrating the sensor unit according to an embodiment.

Referring to FIG. 8, the touch sensor TSM, according to an embodiment, includes electrodes overlapping at least one area of the display panel 100. The electrodes of the touch sensor TSM include a plurality of touch driving electrodes 130, a plurality of touch sensing electrodes 120, and a plurality of noise sensing electrodes 150. Here, the plurality of touch driving electrodes 130 are the second touch electrode members 130 described with reference to FIGS. 4 to 7. The plurality of touch sensing electrodes 120 are the first touch electrode members 120 described with reference to FIGS. 4 to 7. The plurality of noise sensing electrodes 150 are the conductive members 150 described with reference to FIGS. 4 to 7.

The plurality of touch driving electrodes 130 and the plurality of touch sensing electrodes 120 intersect each other. For example, in the illustrated example, the plurality of touch driving electrodes 130 extend in a vertical direction and are disposed at intervals from each other in a horizontal direction. In addition, in the illustrated example, the plurality of touch sensing electrodes 120 extend in the horizontal direction and are disposed at intervals from each other in the vertical direction.

The touch driver 510 supplies a driving signal Ts to the plurality of touch driving electrodes 130 to form a mutual capacitance Cm between the touch driving electrode 130 and the touch sensing electrode 120. When the mutual capacitance Cm is formed between the touch driving electrode 130 and the touch sensing electrode 120, a virtual mutual capacitance Vm is formed between the touch driving electrode 130 and the noise sensing electrode 150.

In the touch sensor TSM, a plurality of sensing channels SC for sensing the mutual capacitance Cm and the virtual mutual capacitance Vm are disposed at a rear end of each of the touch sensing electrodes 120. For example, the plurality of sensing channels SC may correspond to the plurality of touch sensing electrodes 120 in a one-to-one manner.

The sensing channels SC may include an amplifier 571 that receives a sensing signal Rs corresponding to a change in mutual capacitance Cm from each touch sensing electrode 120 and amplifies and outputs the received sensing signal Rs. The amplifier 571 receives a noise signal Ns corresponding to the virtual mutual capacitance Vm from each noise sensing electrode 150 and uses the received noise signal Ns as a reference potential for amplifying the sensing signal Rs.

As the plurality of noise sensing electrodes 150 correspond to the plurality of touch sensing electrodes 120 in a one-to-one manner, each of the sensing channels SC includes a plurality of noise sensing channels connected to the noise sensing electrode 150. For example, FIG. 8 illustrates a first noise sensing channel NSC1 receiving a first noise signal Ns_1, a second noise sensing channel NSC2 receiving a second noise signal Ns_2, a third noise sensing channel NSC3 receiving a third noise signal Ns_3, and a fourth noise sensing channel NSC4 receiving a fourth noise signal Ns_4, but the number of noise sensing channels is substantially the same as the number of sensing channels SC.

Here, the first noise signal Ns_1 represents a virtual mutual capacitance Vm sensed by the first noise sensing electrode 150 among the plurality of noise sensing electrodes 150. The second noise signal Ns_2 represents a virtual mutual capacitance Vm sensed by the second noise sensing electrode 150 among the plurality of noise sensing electrodes 150. The third noise signal Ns_3 represents a virtual mutual capacitance Vm sensed by the third noise sensing electrode 150 among the plurality of noise sensing electrodes 150. The fourth noise signal Ns_4 represents a virtual mutual capacitance Vm sensed by the fourth noise sensing electrode 150 among the plurality of noise sensing electrodes 150.

According to an embodiment, the touch driving circuit 400 may obtain a noise sensing signal using all of the plurality of noise sensing channels and compensate for the sensing signal Rs. However, in this case, although touch sensing sensitivity is increased, a problem of increased power consumption may occur. In order to reduce power consumption, the touch driving circuit 400, according to an embodiment, determines a noise level of the display panel 100 in advance and operates according to the determined noise level to obtain the noise sensing signal from at least some of the noise sensing channels.

For example, when the touch driving circuit 400 determines in advance that the noise level of the display panel 100 is relatively high, the touch driving circuit 400 obtains the noise sensing signal using at least a relatively high percentage (e.g., 80%) of the noise sensing channels. For example, when the touch driving circuit 400 determines in advance that the noise level of the display panel is relatively high, the touch driving circuit 400 activates at least a relatively high percentage (e.g., 80%) of the noise sensing channels. Accordingly, the touch sensor TSM may increase touch sensing sensitivity.

For example, when the touch driving circuit 400 determines in advance that the noise level of the display panel 100 is relatively low, the touch driving circuit 400 obtains the noise sensing signal using a relatively low percentage (e.g., 30%) of the noise sensing channels. For example, when the touch driving circuit 400 determines in advance that the noise level of the display panel is relatively low, the touch driving circuit 400 activates only a relatively low percentage (e.g., 30%) of the noise sensing channels. Accordingly, the touch sensor TSM may increase touch sensing sensitivity while reducing power consumption. The touch sensor TSM may reduce power consumption as a rate at which noise sensing channels are deactivated increases.

The touch sensor TSM may dynamically vary the rate at which the noise sensing channels are deactivated depending on the noise level. For example, the touch sensor TSM may divide all noise sensing channels into an even channel group and an odd channel group, and may independently activate or deactivate each group. For example, the touch sensor TSM may divide all noise sensing channels into 2 or more groups disposed at regular intervals, and may independently activate or deactivate each group.

According to an embodiment, the deactivated noise sensing channel may receive the noise sensing signal from an activated noise sensing channel disposed adjacent thereto. For example, when the touch sensor TSM deactivates the even channel group and activates the odd channel group among the noise sensing channels, each noise sensing channel of the even channel group instead receives the noise sensing signal from the odd channel group adjacent thereto. For example, when the first noise sensing channel NSC1 is deactivated, the first noise sensing channel NSC1 may receive the second noise sensing signal Ns_2 from the activated second noise sensing channel NSC2.

Hereinafter, a method for the touch driving circuit 400 to determine the noise level of the display panel 100 in advance will be described with reference to FIGS. 9 to 11.

FIG. 9 is a waveform diagram illustrating a vertical synchronization signal according to an embodiment.

Referring to FIG. 9, the touch driving circuit 400 may receive a noise level signal indicating a noise level of the display panel 100 from the host 11 that generates image data. The touch driving circuit 400 may be configured to determine the noise level of the display panel 100 based on the noise level signal received from the host 11. Here, the host 11 may be (or may include) an application processor.

The host 11 may analyze image data to be displayed on the display panel 100 and predetermine the noise level of the display panel 100. The host 11 may be configured to determine whether a screen according to the image data is a specific screen and determine the noise level according to the determined result. The specific screen may include, for example, an image with repeated white and black areas (e.g., a zebra image) or an always on display (AOD) image, but the type of the specific screen is not necessarily limited thereto. For example, the host 11 may be configured to determine the noise level as a first level in the case of the always on display (AOD) image, and may be configured to determine the noise level as a second level that is higher than the first level in the case of the zebra image.

According to an embodiment, the host 11 may be configured to determine the noise level depending on whether the screen according to the image data is a still image or a moving image. The host 11 may be configured to determine the noise level as a first level when the screen displays the still image, and may be configured to determine the noise level as a second level that is higher than the first level when the screen displays the moving image.

According to an embodiment, the host 11 may be configured to determine whether an application program executed on a mobile electronic device is a designated program and determine the noise level of the display panel 100 based on the determination. For example, when the executed application program is the designated program, the host 11 may be configured to determine the noise level of the display panel 100 as the second level. For example, if the executed application program is a game program, the host 11 may consider that the noise level generated from the display panel 100 is relatively high and set the noise level to be high. As used herein, the game program is mentioned as an example of the designated program, but the present disclosure is not necessarily limited thereto.

The host 11 may be configured to determine a state of a mobile electronic device to which the display device 10 is applied, for example, whether an electrical charger (e.g., travel adapter) is connected to the mobile electronic device, and determine the noise level according to the determined result.

The host 11 may supply a separate noise level signal indicating the noise level to the display control unit 220 or the touch driving circuit 400 without using the horizontal synchronization signal Hsync. However, as used herein, it will be mainly described that the horizontal synchronization signal Hsync serves as a noise level signal.

The host 11 changes amplitude of the vertical synchronization signal Vsync according to the determined noise level of the display panel 100 and supplies the changed vertical synchronization signal Vsync to the touch driving circuit 400. For example, the embodiment of FIG. 9 illustrates that the host 11 outputs a vertical synchronization signal Vsync with a first amplitude, or the host 11 outputs a vertical synchronization signal Vsync with a second amplitude. The touch driving circuit 400 may indirectly determine the noise level of the display panel 100 by sensing a change in the amplitude of the vertical synchronization signal Vsync.

In FIG. 9, as an example of the change in the amplitude of the vertical synchronization signal Vsync, a first amplitude VS1 of about 1.8V and a second amplitude VS2 of about 1.6V are illustrated, but an amplitude value of the vertical synchronization signal Vsync may be variously changed depending on the number of noise levels of the display panel 100 that are set.

TABLE 1

Amplitude

of Vertical

Synchronization

Noise Level
Signal Vsync

First Level (Lowest Noise Level,
About 1.5 V

e.g., FIG. 12)

Second Level (Noise Level that is Higher
About 1.6 V

Than First Level, e.g., FIG. 13)

Third Level (Noise Level that is Higher
About 1.7 V

Than Second Level, e.g., FIG. 14)

Fourth Level (Noise Level that is Higher
About 1.8 V

Than Third Level, e.g., FIG. 15)

Referring to Table 1, the host 11 may divide the determined noise level of the display panel 100 into the first to fourth levels, and may vary the amplitude of the vertical synchronization signal Vsync to about 1.5 V, about 1.6 V, about 1.7 V, or about 1.8 V depending on each of the first to fourth levels. However, the amplitude value of the vertical synchronization signal Vsync illustrated in Table 1 is only an example, and the present disclosure is not necessarily limited thereto. According to an embodiment, the host 11 may vary the amplitude of the vertical synchronization signal Vsync with a 1-frame period. Therefore, the touch driving circuit 400 may predetermine the noise level of the display panel 100 with 1-frame period and vary the number of activated noise sensing channels. According to the embodiment of the present disclosure described above, power consumption may be reduced while increasing touch sensing sensitivity.

FIG. 10 illustrates a method of driving a sensor unit in a multi-channel driving (MCD) method according to an embodiment.

Referring to FIG. 10, the touch driving circuit 400, according to an embodiment, may perform multi-channel driving (MCD), which groups the touch driving electrodes 130 into a plurality of driving electrodes 130 and supplies a driving signal for each group.

For example, the driving electrodes 130 (DE1 to Den) may be grouped in units of a plurality of driving electrodes 130 and driven simultaneously, which may be understood as multi-channel driving (MCD). In the embodiment of FIG. 10, the driving electrodes 130 (DE1 to Den) may be driven simultaneously (e.g., 2-MCD) in units of two driving electrodes 130. However, this is an example, and the number of driving electrodes 130 grouped is not necessarily limited thereto.

The touch driver 510 may supply driving signals Ts1 to Tsn to the respective driving electrodes 130 (DE1 to Den). The driving signals Ts1 to Tsn may be preset sinusoidal signals. The driving signal generator 200 may supply first and second driving signals Ts1 and Ts2 satisfying orthogonality to the first and second driving electrodes 130 (DE1 and DE2), respectively, during a first driving period DT1.

The touch driver 510 may supply n−1-th and n-th driving signals Tsn−1 and Tsn satisfying orthogonality to n−1-th and n-th driving electrodes 130 (Den−1 and Den) during a second driving period DT2 different from the first driving period DT1.

The touch detector 570 may receive sensing signals according to the driving signals Ts1 to Tsn from the sensing electrodes 120 (SE1 to Sem). The sensing signals may include mixed capacitance values. A touch processing unit 300 may detect (e.g., determine) a touch position based on sensing signals and a reference code.

According to an embodiment, the touch driving circuit 400 may receive a first noise signal using the noise sensing electrodes 150 adjacent to the touch driving electrodes 130 of the remaining group to which the driving signal is not supplied while supplying the driving signal to the touch driving electrodes 130 of a specific group. For example, the touch driving circuit 400 may obtain the first noise signal using the noise sensing electrodes 150 adjacent to the n−1 and n-th driving electrodes 130 (Den−1 and Den) during the first driving period DT1.

According to an embodiment, the touch driving circuit 400 may be configured to determine the noise level of the display panel 100 using the first noise signal. The touch driving circuit 400 may differentially set the noise level of the display panel 100, as will be described later with reference to FIGS. 12 to 15.

The touch driving circuit 400 selects at least some of the plurality of noise sensing channels according to the noise level of the display panel 100, and receives a second noise signal using the selected noise sensing channel.

The touch driving circuit 400 compensates for the touch sensing signal sensed from the touch sensing electrode 120 based on the second noise signal.

FIG. 11 is a waveform diagram illustrating a vertical blank period of a display panel 100 according to an embodiment.

Referring to FIG. 11, the touch driving circuit 400 according to an embodiment receives the first noise signal using all of the plurality of noise sensing channels during a vertical blank period V-blank of the display panel 100. For example, a period 1101 during which the touch driving circuit 400 senses the noise signal may be a vertical blank period V-blank of the display panel 100.

According to an embodiment, the touch driving circuit 400 may be configured to determine the noise level of the display panel 100 using the first noise signal. The touch driving circuit 400 may differentially set the noise level of the display panel 100, as will be described later with reference to FIGS. 12 to 15.

The touch driving circuit 400 selects at least some of the plurality of noise sensing channels according to the noise level of the display panel 100, and receives the second noise signal using the selected noise sensing channel.

The touch driving circuit 400 compensates for the touch sensing signal sensed from the touch sensing electrode 120 based on the second noise signal.

FIGS. 12 to 15 are views for describing noise in a display panel 100 according to an embodiment.

FIGS. 12 to 15 illustrate each sensing area of the touch sensor TSM in a matrix form. Each sensing area expresses the degree of change in mutual capacitance Vm sensed from the corresponding sensing area by darkening of a hatching.

For example, in FIGS. 12 to 15, each sensing area expressed as a first darkening indicates a first area 1201 in which the degree of change in mutual capacitance Vm is the lowest.

For example, in FIGS. 12 to 15, each sensing area expressed as a second darkening indicates a second area 1202 in which the degree of change in mutual capacitance Vm is higher than that of the first area 1201.

For example, in FIGS. 12 to 15, each sensing area expressed as a third darkening indicates a third area 1203 in which the degree of change in mutual capacitance Vm is higher than that of the second area 1202.

For example, in FIGS. 12 to 15, each sensing area expressed as a fourth darkening indicates a fourth area 1204 in which the degree of change in mutual capacitance Vm is higher than that of the third area 1203.

As illustrated in FIGS. 12 to 15, from FIG. 12 to FIG. 15, in the entire area of the touch sensor TSM, a proportion of the third area 1203 and the fourth area 1204 increases, and a proportion of the first area 1201 and the second area 1202 decreases. Therefore, FIG. 12 illustrates a first level with the lowest noise level, FIG. 13 illustrates a second level that is higher than the first level, FIG. 14 illustrates a third level that is higher than the second level, and FIG. 15 illustrates a fourth level that is higher than the third level.

In some embodiments, the noise levels as in FIGS. 12 to 15 are determined by an application that is the host 11. In addition, the host 11 may be configured to transmit a noise level signal corresponding to the noise level to the touch driving circuit 400.

In some embodiments, the noise levels as in