Partial guarding for sensing devices

Abstract

To provide a method for operating a sensor electrode which reduces the effects of interference in a sensing device, a processing system, and an input device.SOLUTION: A method for operating sensor electrodes comprises: driving, during a first period, a first portion of the sensor electrodes with a sensing signal; driving a second portion of the sensor electrodes with a guarding signal; and electrically floating or driving a third portion of the sensor electrodes with a direct current signal. The second portion is adjacent to the first portion. The third portion is adjacent to the second portion but not adjacent to the first portion. The guarding signal and the sensing signal have at least one characteristic in common that is selected from a group consisting of amplitude, phase, and frequency.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates generally to electronic devices, and more particularly to reducing the effects of interference in sensing devices. [Background technology]

[0002] Input devices, including proximity sensor devices, may be used in a variety of electronic systems. Proximity sensor devices may include a surface-defined sensing area within which the proximity sensor device determines the presence, position, force, and / or movement of one or more input objects. Proximity sensor devices may be used to provide interfaces for electronic systems. For example, proximity sensor devices may be used as input devices for larger computer systems, such as touchpads integrated within or as peripherals in notebooks, desktops, automotive multimedia systems, or Internet of Things (IoT) devices. Proximity sensor devices may also be used in smaller computer systems, such as touchscreens integrated into mobile phones. Summary of the Invention

[0003] In one embodiment, a method for activating sensor electrodes includes driving a first portion of the sensor electrodes with a sense signal during a first time period. A second portion of the sensor electrodes is driven with a guarding signal during the first time period. The second portion is located adjacent to the first portion. The guarding signal and the sense signal have at least one common characteristic selected from the group consisting of amplitude, phase, and frequency. A third portion of the sensor electrodes is electrically floating or driven with a direct current (DC) signal during the first time period. The third portion is adjacent to the second portion but not adjacent to the first portion.

[0004] In one embodiment, the processing system includes sensor circuitry coupled to the sensor electrodes. The sensor circuitry is configured to drive a first portion of the sensor electrodes with a sense signal and a second portion of the sensor electrodes with a guarding signal during a first time period. The second portion is adjacent to the first portion. The guarding signal and the sense signal have at least one common characteristic selected from the group consisting of amplitude, phase, and frequency. The sensor circuitry electrically floats or drives a third portion of the sensor electrodes with a direct current (DC) signal during the first time period. The third portion is adjacent to the second portion but not adjacent to the first portion.

[0005] In one embodiment, the input device comprises sensor electrodes and a processing system coupled to the sensor electrodes. The processing system is further configured to drive a first portion of the sensor electrodes with a sense signal and a second portion of the sensor electrodes with a guarding signal during a first time period. The second portion is adjacent to the first portion. The guarding signal and the sense signal have at least one common characteristic selected from the group consisting of amplitude, phase, and frequency. The processing system is configured to electrically float or drive a third portion of the sensor electrodes with a direct current (DC) signal during the first time period. The third portion is adjacent to the second portion but not adjacent to the first portion. [Brief explanation of the drawings]

[0006] So that the above-listed features of the present disclosure may be understood in detail, a more particular description of the present disclosure may be had by reference to embodiments, some of which are illustrated in the accompanying drawings, briefly summarized above. However, the accompanying drawings depict only exemplary embodiments, and therefore should not be considered as limiting the scope of the invention, since the present disclosure may admit of other embodiments which are equally effective.

[0007] [Figure 1] FIG. 1 is a schematic block diagram of an input device according to one or more embodiments.

[0008] [Figure 2] FIG. 2 is a schematic block diagram of an input device and a display device according to one or more embodiments.

[0009] [Figure 3] FIG. 3 is a schematic side view of an input device according to one or more embodiments.

[0010] [Figure 4] FIG. 4 is a flowchart of a method for performing capacitive sensing according to one or more embodiments.

[0011] [Figure 5] FIG. 5 is a timing diagram of a capacity frame according to one or more embodiments.

[0012] [Figure 6A] FIG. 6A is a flowchart of a method for performing capacitive sensing according to one or more embodiments. [Figure 6B] FIG. 6B is a flowchart of a method for performing capacitive sensing according to one or more embodiments. [Figure 6C] FIG. 6C is a flowchart of a method for performing capacitive sensing according to one or more embodiments.

[0013] [Figure 7] FIG. 7 is a timing diagram of a capacity frame according to one or more embodiments.

[0014] For ease of understanding, the same reference numbers are used, where possible, to designate identical elements that are common to multiple figures. Elements disclosed in one embodiment are deemed to be usefully employed in other embodiments without specific description. The drawings referenced herein should not be understood to be drawn to scale unless otherwise specified. Furthermore, for clarity of presentation and explanation, the drawings are often simplified and details or components are omitted. The drawings and discussion serve to explain the principles discussed below, where like names refer to like elements. DETAILED DESCRIPTION OF THE INVENTION

[0015] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory expressed or implied in the preceding background, brief summary or the following detailed description.

[0016] In many input devices, a sensor electrode is disposed adjacent to a display device. In such input devices, a display electrode of the display device is capacitively coupled to the sensor electrode. This increases the capacitance of the sensor electrode, and increases the power required to activate the sensor electrode for capacitive sensing. However, by activating a first portion of the plurality of sensor electrodes for capacitive sensing and driving a second portion of the plurality of sensor electrodes with a guarding signal, the capacitive coupling between the sensor electrode and the display electrode is reduced, advantageously reducing the power required to activate the sensor electrode for capacitive sensing.

[0017] 1 shows an input device 100 configured to reduce capacitive coupling between a sensor electrode and a display electrode. Input device 100 may be configured to provide input to an electronic system (not shown). Some non-limiting examples of electronic systems include desktop computers, laptop computers, notebook computers, tablets, terminals, kiosks, mobile phones, automobile multimedia centers, and IoT devices, among others.

[0018] Input device 100 includes a processing system 110 and sensor electrodes 105. Processing system 110 activates sensor electrodes 105 to detect one or more input objects 140 within a sensing area of input device 100. Exemplary input objects 140 include a finger and a stylus, as shown in FIG.

[0019] The sensing area of the input device 100 encompasses any space within which the input device 100 can detect user input (e.g., user input provided by one or more input objects 140), such as above, around, inside, and / or near the input device 100.

[0020] The sensor electrodes 105 are connected to the processing system 110 via traces 150. The exemplary pattern of the sensor electrodes 105 shown in FIG. 1 comprises an array of the sensor electrodes 105 arranged in a plurality of rows and columns. In one example, the sensor electrodes 105 are arranged in rows 170-181. It is contemplated that the sensor electrodes 105 may be arranged in other patterns, such as a polar array, a repeating pattern, a non-repeating pattern, a non-uniform array, or other suitable arrangements. The sensor electrodes 105 may have a shape such as a circle, a rectangle, a diamond, a star, a square, a non-convex, a convex, a concave, a non-concave, or any other suitable geometry.

[0021] The sensor electrodes 105 may be disposed on a common layer. For example, the sensor electrodes 105 may be disposed on a first side of a common substrate. In other embodiments, the sensor electrodes 105 may be disposed on two or more layers. For example, some of the sensor electrodes 105 may be disposed on a first layer and other parts of the sensor electrodes may be disposed on a second layer. The first and second layers may be disposed on different sides of the common substrate or may be disposed on different substrates.

[0022] The sensor electrodes 105 may be made of a metal mesh or a conductive material such as indium tin oxide (ITO), etc. Furthermore, the sensor electrodes 105 are ohmically isolated from one another, i.e., one or more insulators separate the sensor electrodes and prevent them from electrically shorting to one another.

[0023] The processing system 110 includes sensor circuitry 104. Additionally, the processing system 110 may include a determination module 106. The processing system 110 is configured to activate the sensor electrodes 105 to detect one or more input objects 140 within a sensing area of the input device 100. The processing system 110 resides, in whole or in part, within one or more integrated circuits (ICs). For example, the processing system 110 may include a single IC chip. Alternatively, the processing system 110 may include multiple IC chips.

[0024] The sensor circuitry 104 is connected to the sensor electrodes 105 via routing traces 150 and is configured to drive the sensor electrodes 105 with sensing signals to detect one or more input objects 140 within a sensing area of the input device 100.

[0025] The sensor circuitry 104 may include digital and / or analog circuitry. For example, the sensor circuitry 104 may include transmitter (or driver) circuitry configured to apply sense signals to the sensor electrodes 105 and receiver circuitry that receives result signals from the sensor circuitry 104. The transmitter circuitry may include one or more amplifiers and / or one or more modules configured to apply the sense signals to the sensor electrodes 105. The receiver circuitry may include an analog front end (AFE) with an integrator configured to receive result signals from the sensor electrodes 105.

[0026] In one embodiment, sensor circuitry 104 drives one or more first sensor electrodes 105 with a transcapacitive sensing signal and receives a resulting signal at one or more second sensor electrodes 105 to activate the sensor electrodes 105 for transcapacitive sensing. Activating the sensor electrodes 105 for transcapacitive sensing detects a change in capacitive coupling between the sensor electrodes driven with the transcapacitive sensing signal and the sensor electrodes activated as receiver electrodes. The capacitive coupling may decrease when an input object (e.g., input object 140) connected to system ground approaches the sensor electrodes. Driving the sensor electrodes 105 with the transcapacitive sensing signal includes modulating the sensor electrodes 105 relative to a reference voltage (e.g., system ground).

[0027] The transformer capacitance sensing signal may be a periodic or non-periodic signal that fluctuates between two or more voltages. Furthermore, the transformer capacitance sensing signal has a frequency between 100 kHz and 1 MHz. In other embodiments, other frequencies may be used. The transformer capacitance sensing signal may have a peak-to-peak amplitude ranging from about 1 V to about 10 V. However, in other embodiments, the transformer capacitance sensing signal may have a peak-to-peak amplitude greater than about 10 V. Additionally, the transformer capacitance sensing signal may have a square waveform, a sinusoidal waveform, a triangular waveform, a trapezoidal waveform, or a sawtooth waveform, among others.

[0028] In some embodiments, activating the sensor electrodes 105 and receiving the resultant signals includes holding the sensor electrodes 105 at a substantially constant voltage or modulating the sensor electrodes 105 with respect to the trans-capacitive sensing signals. The resultant signals include effects corresponding to one or more trans-capacitive sensing signals and / or corresponding to one or more sources of environmental interference (e.g., other electromagnetic signals).

[0029] In one embodiment, sensor circuitry 104 activates one or more first sensor electrodes 105 for absolute capacitive sensing by driving the first sensor electrodes 105 with an absolute capacitive sensing signal and receiving a resulting signal at the driven sensor electrodes. Activating the sensor electrodes 105 for absolute capacitive sensing detects a change in capacitive coupling between the electrodes driven with the absolute capacitive sensing signal and an input object (e.g., input object 140). The capacitive coupling of the sensor electrodes 105 driven with the absolute capacitive sensing signal varies when an input object (e.g., input object 140) connected to system ground approaches the sensor electrodes.

[0030] The absolute capacitance sensing signal is a periodic or non-periodic signal that fluctuates between two or more voltages. Furthermore, the absolute capacitance sensing signal has a frequency between 100 kHz and 1 MHz. In other embodiments, other frequencies may be used. Additionally, the absolute capacitance sensing signal may have a square waveform, a sinusoidal waveform, a triangular waveform, a trapezoidal waveform, or a sawtooth waveform, among others. The absolute capacitance sensing signal may have a peak-to-peak amplitude ranging from about 1 V to about 10 V. However, in other embodiments, the absolute capacitance sensing signal may have a peak-to-peak amplitude greater than about 10 V. In various embodiments, driving the sensor electrode 105 with the absolute capacitance sensing signal includes modulating the sensor electrode 105. The resulting signal received during absolute capacitive sensing corresponds to one or more absolute capacitance sensing signals and / or includes effects corresponding to one or more environmental interference sources (e.g., other electromagnetic signals). The absolute capacitance sensing signal may be the same as or different from the transcapacitive sensing signal used for transcapacitive sensing.

[0031] The sensor circuitry 104 activates a first portion of the sensor electrodes 105 for absolute capacitive sensing. The first portion of the sensor electrodes 105 corresponds to one or more of the sensor electrodes 105. The first portion of the sensor electrodes 105 corresponds to a first subset of the sensor electrodes 105. In one embodiment, the first portion of the sensor electrodes 105 corresponds to one or more of the rows 170-181. The first portion of the sensor electrodes may correspond to two or more of the rows 170-181.

[0032] The sensor circuitry 104 may simultaneously activate two or more of the sensor electrodes 105 for absolute capacitive sensing. For example, the sensor circuitry 104 simultaneously activates each of the sensor electrodes 105 of a first portion of the sensor electrodes 105 for absolute capacitive sensing. The sensor circuitry 104 may simultaneously activate each of the sensor electrodes 105 of a common row (e.g., rows 170-181) for absolute capacitive sensing. Furthermore, the sensor circuitry 104 may simultaneously activate each of the sensor electrodes of two or more rows (e.g., two or more of rows 170-181) for absolute capacitive sensing.

[0033] The sensor circuitry 104 drives a second portion of the sensor electrodes 105 with a guarding signal. The second portion of the sensor electrodes 105 corresponds to one or more sensor electrodes 105. The second portion of the sensor electrodes 105 corresponds to a second subset of the sensor electrodes 105. In one embodiment, the second portion of the sensor electrodes 105 corresponds to two or more sensor electrodes 105. The second portion of the sensor electrodes 105 corresponds to one or more of the rows 170-181. In one embodiment, the second portion of the sensor electrodes 105 corresponds to two or more of the rows 170-181. The second portion of the sensor electrodes 105 corresponds to more sensor electrodes than the first portion of the sensor electrodes 105. Alternatively, the second portion of the sensor electrodes 105 corresponds to fewer sensor electrodes than the first portion of the sensor electrodes 105. In one embodiment, the first and second portions of the sensor electrodes 105 correspond to the same number of sensor electrodes.

[0034] The sensor circuitry drives the sensor electrodes in one or more rows (e.g., rows 170-181) of the sensor electrodes 105 with the guarding signal. Driving the sensor electrodes in one or more rows (e.g., rows 170-181) of the sensor electrodes 105 simultaneously with the guarding signal includes driving each sensor electrode in the one or more rows (e.g., rows 170-181) of the sensor electrodes 105 with the guarding signal.

[0035] A sensor electrode driven with a guarding signal may be referred to as a guarded sensor electrode. Driving the sensor electrode with the guarding signal reduces the voltage difference between the guarded sensor electrode and a sensor electrode driven in parallel with an absolute capacitive sense signal. Accordingly, driving one or more first sensor electrodes with a guarding signal while applying a sense signal to one or more second sensor electrodes results in little or no change in capacitance between the guarded sensor electrode and the sensor electrode driven with the absolute capacitive sense signal.

[0036] The guarding signal has at least one characteristic selected from the group consisting of amplitude, phase, and frequency in common with the absolute capacitance sensing signal. In one embodiment, the guarding signal has an amplitude, phase, and frequency in common with the absolute capacitance sensing signal. In one embodiment, one of the amplitude, phase, and frequency is common with the absolute capacitance sensing signal. In another embodiment, the guarding signal has an amplitude, phase, or frequency in common with the absolute capacitance sensing signal. In one embodiment, the guarding signal has a phase, amplitude, or frequency in common with the absolute capacitance sensing signal. Alternatively, the guarding signal has a frequency, amplitude, or phase in common with the absolute capacitance sensing signal.

[0037] Additionally, the guarding signal and the absolute capacitive sensing signal may have a common waveform. In one embodiment, the guarding signal may be the same as the absolute capacitive sensing signal.

[0038] The sensor circuitry 104 drives a third portion of the sensor electrodes 105 with a reference signal. The third portion of the sensor electrodes 105 corresponds to a third subset of the sensor electrodes 105. The sensor circuitry 104 may drive the sensor electrodes in one or more rows (e.g., rows 170-181) of the sensor electrodes 105 with the reference signal. Driving the sensor electrodes in one or more rows (e.g., rows 170-181) of the sensor electrodes 105 with the reference signal includes sequentially driving each sensor electrode in the one or more rows (e.g., rows 170-181) of the sensor electrodes 105 with the reference signal. The reference signal may be a direct current (DC) signal. In one embodiment, the reference signal is a ground signal of the input device 100.

[0039] The sensor circuitry 104 electrically floats a third portion of the sensor electrodes 105. In one embodiment, the sensor circuitry 104 electrically floats one or more of the sensor electrodes 105. An electrically floating sensor electrode is not actively driven by the sensor circuitry 104. For example, the sensor circuitry 104 may be decoupled from one or more of the sensor electrodes 105 to electrically float the one or more sensor electrodes. Additionally, the sensor circuitry 104 may electrically float one or more of the sensor electrodes by holding the sensor electrodes in a high impedance state.

[0040] The third portion of the sensor electrodes 105 corresponds to more sensor electrodes than the first and / or second portion of the sensor electrodes 105. Alternatively, the third portion of the sensor electrodes 105 corresponds to fewer sensor electrodes than the first and / or second portion of the sensor electrodes 105. In one embodiment, the first, second, and third portions of the sensor electrodes 105 correspond to the same number of sensor electrodes.

[0041] The determination module 106 receives the resultant signals from the sensor circuitry 104 and processes the resultant signals to determine changes in the capacitive coupling of the sensor electrodes 105. The determination module 106 uses the changes in the capacitive coupling of the sensor electrodes 105 to determine position information of one or more input objects (e.g., input object 140).

[0042] In one or more embodiments, measurements of changes in capacitive coupling determined from resultant signals received from the sensor electrodes 105 may be used by the determination module 106 to form a capacitance image. The resultant signals used to detect changes in capacitive coupling are received during a capacitance frame. A capacitance frame may correspond to one or more capacitance images. Multiple capacitance images may be acquired over multiple time periods, and differences between the images may be used to derive information about an input object 140 within a sensing area of the input device 100. For example, successive capacitance images acquired over successive time periods may be used to track the movement of one or more input objects entering, present in, and within the sensing area.

[0043] As used herein, "position information" broadly encompasses absolute position, relative position, velocity, acceleration, and other types of spatial information. Exemplary "zero-dimensional" position information includes near / far or contact / no-contact information. Exemplary "one-dimensional" position information includes position along an axis. Exemplary "two-dimensional" position information includes motion in a plane. Exemplary "three-dimensional" position information includes instantaneous or average velocity in space. Further examples include other representations of spatial information. Historical information regarding one or more types of position information (e.g., including historical data tracking position, motion, and instantaneous velocity over time) may also be determined and / or stored.

[0044] In some embodiments, input device 100 is a touchscreen interface that overlaps at least a portion of a display of a display device. For example, as shown in Figure 2, input device 100 is shown overlapping the display of display device 200. Display device 200 includes a display panel 210 communicatively connected to a display driver 208 and gate selection circuitry 230. Display panel 210 includes display electrodes that are driven to update subpixel electrodes 226 of display panel 210. The display electrodes include, among other things, data lines 222, gate lines 224, and / or emission control lines 223.

[0045] The data lines 222 are connected to the display driver 208, and the gate lines 224 are connected to the gate selection circuitry 230. Furthermore, the light emission control lines 223 are connected to the light emission control circuitry. Each of the sub-pixel electrodes 226 is connected to one of the gate lines 224 and one of the data lines 222. Furthermore, in one or more embodiments, each of the sub-pixel electrodes 226 is connected to the light emission control line 223.

[0046] The gate selection circuitry 230 is configured to apply gate select and gate deselect signals to the gate lines 224 to select (activate) and deselect (deactivate) the corresponding sub-pixels for updating. Furthermore, the emission control lines 223 are driven by the emission control circuitry to control the brightness of the sub-pixels 26.

[0047] The display driver 208 comprises display driver circuitry configured to drive the data lines 222 with subpixel data signals to update selected subpixel electrodes 226 and update the display of the display device 200. For example, the display driver 208 may apply display update signals to the data lines 222 during a display update period.

[0048] The display driver 208 is configured to update the subpixel electrodes 226 to update the image displayed on the display panel 210 during a display period. The display frame is updated or refreshed approximately once every 16 ms, producing a display refresh rate of approximately 60 Hz. In other embodiments, other display refresh rates may be employed. For example, the display refresh rate may be 90 Hz, 120 Hz, 140 Hz, or greater.

[0049] The display driver 208, the sensor circuitry 104, and the decision module 106 may be part of a common processing system (e.g., processing system 211). Alternatively, the display driver 208 may be part of a first processing system, and the sensor circuitry 104 and the decision module 106 may be part of a second processing system. Furthermore, the display driver 208, the sensor circuitry 104, and the decision module 106 may be part of a common IC chip. Alternatively, one or more of the display driver 208, the sensor circuitry 104, and the decision module 106 may be located on a first IC chip, and one or more of the display driver 208, the sensor circuitry 104, and the decision module 106 may be located on a second IC chip.

[0050] In various embodiments, the sensor circuitry 104 is configured to drive the sensor electrodes for capacitive sensing at a capacitive frame rate during the capacitive frames. In one embodiment, each sensor electrode 105 is activated for absolute capacitive sensing during each capacitive frame. Furthermore, each of the multiple capacitive frames may include multiple periods during which a different sensor electrode 105 is activated for absolute capacitive sensing.

[0051] The "volume frame rate" (the rate at which successive volume images are acquired) may be the same as or different from the "display frame rate" (the rate at which the display image is updated, including refreshing the screen to redisplay the same image). In various embodiments, the volume frame rate is an integer multiple of the display frame rate. In other embodiments, the volume frame rate is a fractional multiple of the display frame rate. In yet other embodiments, the volume frame rate may be any fraction or multiple of the display frame rate. Furthermore, the volume frame rate may be a rational fractional multiple of the display rate (e.g., 1 / 2, 2 / 3, 1, 3 / 2, 2). In one or more embodiments, the volume frame rate may remain constant while the display frame rate is changed. In other embodiments, the volume frame rate may be increased or decreased while the display frame rate remains constant. Alternatively, the volume frame rate may not be synchronized with the display refresh rate, or the volume frame rate may be a non-rational fractional multiple of the display rate to minimize interfering "beat frequencies" between display updates and input sensing.

[0052] In one or more embodiments, capacitive sensing (or input sensing) and display updating may occur during at least partially overlapping time periods. For example, sensor circuitry 104 may be configured to activate sensor electrodes 105 for capacitive sensing while display driver 208 activates gate lines 224 and data lines 222 to update the image displayed by display panel 210. For example, updating display panel 210 and activating sensor electrodes 105 for capacitive sensing may be asynchronous with one another. Furthermore, updating display panel 210 and activating sensor electrodes 105 for capacitive sensing may or may not be synchronized with one another.

[0053] In one or more embodiments, updating the display panel 210 and activating the sensor electrodes 105 for capacitive sensing may occur in non-overlapping periods. For example, updating the display panel 210 may occur during a display update period, and activating the sensor electrodes 105 for capacitive sensing may occur during a non-display update period. A non-display update period may be a blanking period (e.g., during a vertical blanking period) occurring between the last line of a display frame and the first line of the next display frame. Furthermore, a non-display update period may occur between display line update periods for two consecutive display lines of a display frame, with the non-display update period having a temporal length at least equal to the display line update periods. In such embodiments, the non-display update period may be referred to as a long horizontal blanking period, or long h-blanking period, where the blanking period occurs between two display line update periods in a display frame and has a temporal length at least equal to the display line update periods.

[0054] 3 illustrates a partial side view of input device 100 and display device 200 according to one or more embodiments. In the embodiment of FIG. 3, display panel 210 is an organic light emitting diode (OLED) display panel. However, in other embodiments, other display types (e.g., liquid crystal display (LCD), etc.) may be used.

[0055] As shown, the display panel 210 includes a substrate 328, a subpixel electrode 226, an organic material layer 330, a cathode electrode 340, a display layer 350, and a sealing layer 360. The cathode electrode 340 may be a sheet of resistive material configured to overlap the subpixel electrode 226. The cathode electrode 340 may be connected to the display driver 208 and driven by the display driver 208 to provide a low-impedance reference voltage. In an embodiment where the display panel 210 is an LCD panel, the cathode electrode 340 is replaced with a common voltage (Vcom) electrode layer. Furthermore, the cathode electrode 340 (or Vcom electrode layer) may also be referred to as a reference electrode layer.

[0056] The substrate 328 may be a flexible substrate. Alternatively, the substrate 328 may be a rigid substrate. The display layer 350 may include, for example, one or more polarizers, color filters, etc. As shown, the sensor electrodes 105 are disposed on the sealing layer 360. In an embodiment including a lens, instead of the sealing layer 360, the sensor electrodes 105 are disposed on the lens. The lens may be disposed on the sealing layer 360 or may be included instead of the sealing layer 360.

[0057] The traces 150 may be disposed on a layer between the sensor electrodes 105 and the display panel 210. Alternatively, the traces 150 may be disposed on a layer of the display panel 210 between the substrate 328 and the sealing layer 360.

[0058] As discussed above, because the sensor electrodes 105 are disposed above the display panel 210, the display electrodes of the display panel 210 undesirably capacitively couple with the sensor electrodes 105. This capacitive coupling, sometimes referred to as background capacitance, increases the capacitance of the sensor electrodes 105. Furthermore, interference may be introduced into the sensor electrodes 105 via the background capacitance. However, by driving some of the sensor electrodes with a guarding signal while driving other portions of the sensor electrodes for capacitive sensing, the interference is reduced. Furthermore, by driving a second portion of the sensor electrodes with a reference signal or electrically floating a second portion of the sensor electrodes, the background capacitance is reduced. Advantageously, the power used to drive the sensor electrodes is reduced while facilitating detection of an input object.

[0059] FIG. 4 is a flowchart of a method 400 for reducing background capacitance and interference when performing capacitive sensing, according to one or more embodiments. Method 400 is described with reference to FIGS. 2 and 5. In operation 410, sensor circuitry 104 drives a first portion of the sensor electrodes with a sense signal during a first time period. The sense signal may be an absolute capacitive sense signal. Furthermore, sensor circuitry 104 obtains a corresponding result signal from each driven sensor electrode. For example, sensor circuitry 104 drives each sensor electrode in row 176 with an absolute capacitive sense signal during the first time period and obtains a corresponding result signal from each driven sensor electrode. The first time period may correspond to a first portion of a first capacitive frame. FIG. 5 illustrates a portion of a capacitive frame 500 (e.g., the first capacitive frame). As illustrated, capacitive frame 500 includes at least three time periods during which capacitive sensing is performed. For example, capacitive frame 500 includes at least a first time period, a second time period, and a third time period. In various embodiments, the capacitive frame 500 may include additional periods such that each of the sensor electrodes 105 is activated for absolute capacitive sensing prior to the completion of the capacitive frame. The additional periods may occur before the first period, after the third period, and / or between the first, second, and third periods.

[0060] In operation 420, each sensor electrode of the second portion of the sensor electrodes is driven with a guarding signal during a first time period. For example, sensor circuitry 104 drives each sensor electrode of row 177 with a guarding signal during the first time period. In this example, the row selected to obtain a result signal (e.g., row 176) is adjacent to the guarded row (e.g., row 177). In various embodiments, during the first time period, display electrodes (e.g., data lines 222, gate lines 224, and emission control lines 223) are activated for display updating. For example, in one embodiment, display driver 208 drives data lines 222, and gate selection circuitry 230 drives gate lines 224 to update sub-pixel electrodes 226 during the first time period.

[0061] In one or more embodiments, sensor circuitry 104 driving a second portion of sensor electrodes 105 with a guarding signal additionally includes driving sensor electrodes in one or more of rows 170-175 and 179-181 with the guarding signal during the first time period. For example, sensor electrodes in row 175 may be driven with the guarding signal during the first time period. In such embodiments, the row selected to obtain the result signal (e.g., row 176) is between two guarded rows (e.g., rows 174 and 177).

[0062] Guarding a second portion of the sensor electrodes adjacent to a first portion of the sensor electrodes activated for absolute capacitive sensing reduces the effect of display interference caused by activating the display electrodes for display updating. For example, driving the sensor electrodes of row 177 with a guarding signal at least partially reduces the effect on the sensor electrodes of row 176 of interference caused by the display electrodes driven for display updating (e.g., data lines 222, gate lines 224, and / or cathode electrodes 340). Reducing the effect of interference caused by driving the display electrodes for display updating reduces the effect of interference in the resultant signal received at the sensor electrodes activated for absolute capacitive sensing. Accordingly, the effect corresponding to input object 140 becomes a larger portion of the resultant signal, improving the ease of detection of input object 140.

[0063] In operation 430, a third portion of the sensor electrodes 105 are electrically floated or driven with a DC signal during the first time period. The third portion of the sensor electrodes 105 are adjacent to the second portion of the sensor electrodes but not adjacent to the first portion of the sensor electrodes. Operation 430 may include driving each sensor electrode in the third row of sensor electrodes with a reference signal or electrically floating each sensor electrode in the third row of sensor electrodes during the first time period. For example, in one embodiment, sensor electrodes in row 178 are driven with a reference signal by sensor circuitry 104 during the first time period. Sensor circuitry 104 additionally drives sensor electrodes in one or more of rows 170-175 and 179-181 with a reference signal during the first time period. The reference signal may be a constant voltage signal. For example, the reference signal may be a DC signal. In another embodiment, in operation 430, sensor circuitry 104 electrically floats the sensor electrodes in row 178 during the first time period. For example, sensor circuitry 104 may be isolated from the sensor electrodes of row 178 during the first time period so that the sensor electrodes are not actively driven by sensor circuitry 104. Alternatively, sensor circuitry 104 may place the sensor electrodes of row 178 in a high impedance state. In one or more embodiments, sensor circuitry 104 may additionally electrically float the sensor electrodes of one or more of rows 170-175 and 179-181 during the first time period. Driving sensor electrode rows 170-175 and 179-181 with a reference voltage or electrically floating these rows reduces background capacitance between sensor electrodes 105 and the display electrodes of display panel 210.

[0064] As shown in FIG. 5 , during a first time period, a first portion of the sensor electrodes 105 are driven with an absolute capacitive sensing signal for absolute capacitive sensing, a second portion of the sensor electrodes 105 are driven with a guarding signal, and a third portion of the sensor electrodes 105 are electrically floating or driven with a DC signal. For example, each of the rows 170-181 is either activated for absolute capacitive sensing, driven with a guard signal, or driven with a reference signal or electrically floating. The number of rows 170-181 activated for absolute capacitive sensing may be more or less than two. For example, one or more of rows 170-174 and 177-181 may be activated for absolute capacitive sensing. Alternatively, the rows 170-181 activated for absolute capacitive sensing may be adjacent to each other or spatially separated from each other. Furthermore, the number of rows 170-181 of sensor electrodes 105 that are activated for absolute capacitive sensing is less than the total number of rows. In one embodiment, the number of rows 170-181 that are driven with guarding signals during the first time period may be more or less than two. For example, one or more of rows 170-173 and 178-181 may additionally be driven with guarding signals. Furthermore, the number of rows 170-181 that are driven with guarding signals is less than the total number of rows 170-181 that are not activated for absolute capacitive sensing.

[0065] The first portion of the sensor electrodes 105 and the fifth and / or sixth portion of the sensor electrodes 105 include one or more common sensor electrodes. The second portion of the sensor electrodes 105 and the sixth portion of the sensor electrodes include one or more common sensor electrodes. The third portion of the sensor electrodes 105 and the sixth portion of the sensor electrodes 105 include one or more common sensor electrodes.

[0066] 5 , during a second time period, a fourth portion of the sensor electrodes 105 are driven with an absolute capacitance sensing signal for absolute capacitive sensing, a fifth portion of the sensor electrodes 105 are driven with a guarding signal, and a sixth portion of the sensor electrodes 105 are either electrically floating or driven with a DC voltage. For example, one or more of rows 177 and 178 are driven for capacitive sensing, and at least rows 176 and 179 are driven with a guarding signal. The remaining rows are either applied with a reference voltage or electrically floating. Furthermore, during a third time period, a seventh portion of the sensor electrodes 105 are driven with an absolute capacitance sensing signal for absolute capacitive sensing, an eighth portion of the sensor electrodes 105 are driven with a guarding signal, and a ninth portion of the sensor electrodes 105 are either electrically floating or driven with a DC voltage. For example, during the third time period, one or more of rows 179 and 180 are driven for capacitive sensing, and at least rows 178 and 181 are driven with a guarding signal. Additionally, the remaining rows are either driven with a reference voltage or are electrically floating.

[0067] The fourth portion of the sensor electrodes 105 and the eighth and / or ninth portions of the sensor electrodes 105 include one or more common sensor electrodes. The fifth portion of the sensor electrodes 105 and the ninth portion of the sensor electrodes include one or more common sensor electrodes. The sixth portion of the sensor electrodes 105 and the ninth portion of the sensor electrodes 105 include one or more common sensor electrodes.

[0068] 6A, 6B, and 6C illustrate a method 600 for performing capacitive sensing according to one or more embodiments. Method 600 is described with reference to FIGS. 1 and 5. Additionally, operations 610, 612, and 614 of method 600 are similar to operations 410, 420, and 430 of method 400 of FIG. 4. For example, in operation 610, sensor circuitry 104 drives each sensor electrode in row 176 with an absolute capacitive sensing signal during a first period of a first capacitive frame (e.g., capacitive frame 500) and obtains a resulting signal from each driven sensor electrode.

[0069] In operation 612, sensor circuitry 104 drives each sensor electrode in row 177 with a guarding signal during a first time period. Row 177 is adjacent to row 176.

[0070] In operation 614, sensor circuitry 104 drives the sensor electrodes of row 178 to a reference voltage or electrically floats them during a first time period. Row 178 is adjacent to row 177, and row 177 is between rows 176 and 178.

[0071] In operation 616, each sensor electrode in a fourth row of sensor electrodes is driven with a sense signal during a first time period. For example, sensor circuitry 104 drives each sensor electrode in row 175 with an absolute capacitive sense signal during the first time period and obtains a resultant signal from each driven sensor electrode. The driving of the sensor electrodes in rows 175 and 176 with the absolute capacitive sense signals may at least partially overlap in time. Furthermore, the sensor electrodes in rows 175 and 176 are driven simultaneously with the absolute capacitive sense signals by sensor circuitry 104.

[0072] In operation 618, each sensor electrode in the fifth row of sensor electrodes is driven with a guarding signal during the first time period. For example, sensor circuitry 104 drives each sensor electrode in row 174 with a guarding signal during the first time period. Furthermore, row 174 is adjacent to row 175.

[0073] In operation 620, each sensor electrode in the sixth row of sensor electrodes is driven with a reference signal or electrically floated during a first time period. For example, in one embodiment, during the first time period, the sensor electrodes in row 173 are driven with the reference signal by sensor circuitry 104. In one or more embodiments, sensor circuitry 104 additionally drives the sensor electrodes in one or more of rows 170-172 and 179-181 with the reference signal. Alternatively, in operation 620, sensor circuitry 104 electrically floats the sensor electrodes in row 173 during the first time period. In one or more embodiments, sensor circuitry 104 additionally electrically floats the sensor electrodes in one or more of rows 170-172 and 179-181.

[0074] In operation 622, each sensor electrode in a second row of sensor electrodes is driven with a sense signal during a second time period of the first capacitive frame. For example, sensor circuitry 104 drives each sensor electrode in row 177 with an absolute capacitive sense signal during a second time period of the first capacitive frame (e.g., capacitive frame 500) and obtains a resultant signal from each driven sensor electrode. The second time period corresponds to a second portion of the first capacitive frame and may be contiguous with the first time period.

[0075] In operation 624, sensor circuitry 104 drives each sensor electrode in row 176 with a guarding signal for a second time period.

[0076] In operation 626, each sensor electrode in the fourth row of sensor electrodes is driven with the reference signal during the second time period, or each sensor electrode in the fourth row of sensor electrodes is allowed to electrically float during the second time period. In one embodiment, sensor circuitry 104 drives the sensor electrodes in row 175 with the reference signal during the second time period. Alternatively, in operation 626, sensor circuitry 104 allows the sensor electrodes in row 175 to electrically float.

[0077] Further, during the second time period, sensor circuitry 104 drives the sensor electrodes of row 178 with an absolute capacitive sensing signal. Additionally, during the second time period, sensor circuitry 104 drives the sensor electrodes of row 180 with a reference signal, or sensor circuitry 104 electrically floats the sensor electrodes of row 180. Sensor circuitry 104 may also drive the sensor electrodes of rows 170-174 and 181 with a reference signal, or may electrically float the sensor electrodes of rows 170-174 and 181 during the second time period.

[0078] In operation 628, each sensor electrode in a seventh row of sensor electrodes is driven with a sense signal during a third time period of the first capacitive frame. For example, sensor circuitry 104 drives sensor electrodes in row 179 with absolute capacitive sense signals during the third time period and obtains resultant signals from the sensor electrodes in the driven row 179. The third time period corresponds to a third portion of the first capacitive frame (e.g., frame 500) and may be contiguous with the second time period. Furthermore, the first, second, and third time periods do not overlap with one another.

[0079] In operation 630, each sensor electrode in the third row is driven with a guarding signal during a third time period. For example, sensor circuitry 104 drives each sensor electrode in row 178 with a guarding signal during a third time period.

[0080] In operation 632, each sensor electrode in the second row of sensor electrodes is driven with the reference signal during a third time period or each sensor electrode in the second row of sensor electrodes is allowed to electrically float during the third time period. For example, in one embodiment, sensor circuitry 104 drives each sensor electrode in row 177 with the reference signal or allows each electrode in row 177 to electrically float during the third time period.

[0081] Additionally, during the third time period, sensor circuitry 104 drives the sensor electrodes of row 180 with the absolute capacitance sensing signal. Additionally, during the third time period, sensor circuitry 104 drives the sensor electrodes of row 181 with the guarding signal. Furthermore, during the third time period, sensor circuitry 104 drives each of the sensor electrodes of rows 170-177 with the reference signal. Alternatively, during the third time period, sensor circuitry 104 electrically floats each of the sensor electrodes of rows 170-177.

[0082] 7 illustrates a period of a capacitive frame 700, according to one or more embodiments. As shown in FIG. 7, during a first period, sensor circuitry 104 activates rows 170-172 for absolute capacitive sensing. Additionally, during the first period, sensor circuitry 104 applies guarding signals to rows 173-174 and applies reference signals to rows 175-181, or electrically floats rows 175-181.

[0083] 7 , sensor circuitry 104 either activates a subset of rows 170-181 for absolute capacitive sensing, drives a subset of rows 170-181 with a guarding signal, drives a subset of rows 170-181 with a reference signal, or electrically floats a subset of rows 170-181. For example, during a first period of capacitive frame 700, sensor circuitry 104 drives sensor electrodes 105 in rows 170-172 for absolute capacitive sensing and applies guarding signals to sensor electrodes 105 in rows 173-174. Additionally, during the first period, sensor circuitry 104 applies a reference signal to or electrically floats sensor electrodes 105 in rows 175-181.

[0084] During a second period of the capacitive frame 700, the sensor circuitry 104 activates the sensor electrodes 105 in rows 173-175 for absolute capacitive sensing and applies guarding signals to the sensor electrodes 105 in rows 171-172 and 176-177. Additionally, during the second period, the sensor circuitry 104 applies reference signals to the sensor electrodes 105 in rows 170 and 178-181, or electrically floats them.

[0085] 7, sensor circuitry 104 activates rows 176-178 for absolute capacitive sensing and applies guarding signals to rows 174-175 and 179-180. Additionally, during the third period, sensor circuitry 104 applies reference signals to rows 170 and 178-181, or electrically floats rows 175-181.

[0086] 7, sensor circuitry 104 activates rows 179-181 for absolute capacitive sensing and applies guarding signals to rows 177-181. Additionally, during a third period, sensor circuitry 104 applies a reference signal to row 176, or electrically floats row 176.

[0087] In other embodiments, the number of rows 170-181 driven for absolute capacitive sensing during each period of a capacitive frame may differ from the number of rows shown in FIG. 7. For example, while FIG. 7 shows a subset of three rows being driven for absolute capacitive sensing during each period, in other embodiments, the subset may include more than three rows. Furthermore, the number of rows in one or more first periods of a capacitive frame may differ from the number of rows in the subset in one or more second periods of a capacitive frame. Furthermore, the number of rows in the subset may vary from capacitive frame to capacitive frame.

[0088] In various embodiments, the order of the periods may differ from that shown in Figure 7. For example, in one embodiment, the third period of the capacitance frame 700 may occur before the first period of the capacitance frame 700. In other embodiments, other orders of the periods are possible. Furthermore, each subset of rows 170-181 may include a contiguous grouping of rows, as shown in Figure 7. In other embodiments, at least two of the rows 170-181 included in each subset are spatially separated from one another.

[0089] Thus, the embodiments and examples set forth herein are presented to best explain embodiments and particular applications thereof in accordance with the present technology and to enable those skilled in the art to make and use the present disclosure. However, those skilled in the art will recognize that the foregoing description and examples have been presented for purposes of illustration and example only. The description set forth herein is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed.

[0090] In view of the above, the scope of the present disclosure is determined by the claims that follow.

Claims

1. a sensor circuit portion connected to the sensor electrodes; driving a first portion of the sensor electrodes with a sense signal during a first time period; driving a second portion of the sensor electrode adjacent to the first portion with a guarding signal during the first period; driving a third portion of the sensor electrode adjacent to the second portion but not adjacent to the first portion with a direct current (DC) signal during the first time period; a sensor circuit unit configured as follows: the guarding signal and the sensing signal have at least one common characteristic selected from the group consisting of amplitude, phase, and frequency; Processing system.

2. the sensor circuitry is further configured to drive a fourth portion of the sensor electrodes with the guarding signal during the first time period. The processing system of claim 1 .

3. the sensor circuitry is further configured to drive, during the first time period, a fifth portion of the sensor electrode adjacent to the fourth portion but not adjacent to the first portion with the DC signal. The processing system of claim 2 .

4. The sensor circuit unit driving a fourth portion of the sensor electrodes with the sense signal during a second time period; driving a fifth portion of the sensor electrodes with the guarding signal during the second time period; During the second time period, a sixth portion of the sensor electrode adjacent to the fifth portion but not adjacent to the fourth portion is driven with the DC signal. and further configured as follows: The processing system of claim 1 .

5. the first portion and the fifth portion include at least a first sensor electrode among the sensor electrodes in common, the second portion and the sixth portion include at least a second sensor electrode among the sensor electrodes in common, and the third portion and the sixth portion include at least a third sensor electrode among the sensor electrodes in common; The processing system of claim 4.

6. The sensor circuit unit driving a seventh portion of the sensor electrodes with the sense signal during a third time period; driving an eighth portion of the sensor electrodes with the guarding signal during the third time period; During the third time period, a ninth portion of the sensor electrode adjacent to the eighth portion but not adjacent to the seventh portion is driven with the DC signal. and further configured as follows: The processing system of claim 4.

7. the fourth portion and the eighth portion include at least a first sensor electrode among the sensor electrodes in common, the fifth portion and the ninth portion include at least a second sensor electrode among the sensor electrodes in common, and the sixth portion and the ninth portion include at least a third sensor electrode among the sensor electrodes in common; The processing system of claim 6.

8. A sensor electrode; a processing system connected to the sensor electrodes; driving a first portion of the sensor electrodes with a sense signal during a first time period; driving a second portion of the sensor electrode adjacent to the first portion with a guarding signal during the first period; driving a third portion of the sensor electrode adjacent to the second portion but not adjacent to the first portion with a direct current (DC) signal during the first time period; a processing system configured to Equipped with the guarding signal and the sensing signal have at least one common characteristic selected from the group consisting of amplitude, phase, and frequency; Input devices.

9. further comprising an organic light emitting diode (OLED) display device; the processing system is further configured to update the display of the display device during the first period of time.

9. The input device of claim 8.

10. 1. A method for activating a sensor electrode, comprising: driving a first portion of the sensor electrodes with a sense signal during a first time period; Driving a second portion of the sensor electrode disposed adjacent to the first portion with a guarding signal during the first time period; driving a third portion of the sensor electrode adjacent to the second portion but not adjacent to the first portion with a direct current (DC) signal during the first time period; Including, the guarding signal and the sensing signal have at least one common characteristic selected from the group consisting of amplitude, phase, and frequency; method.

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