Touch signal detection circuit, touch signal detection method and touch position positioning method

Abstract

The embodiment of the invention provides a touch signal detection circuit, a touch signal detection method and a touch position positioning method, and the touch signal detection circuit comprises an interference detection module, a touch detection module, a current copying module and signal channels corresponding to sensing units. The interference detection module is connected with the reference signal channel and is used for carrying out current detection on the reference signal channel to obtain interference current; the input end of the current copying module is connected with the interference detection module, the output end of the current copying module is connected with the touch detection module, the current copying module is used for copying interference current and injecting copied current obtained through copying into the touch detection module, and the direction of the copied current is opposite to that of the interference current; and the touch detection module is also connected with other signal channels except the reference signal channel and is used for carrying out touch signal detection on the connected signal channels. Active compensation of display interference is achieved, the anti-interference capacity and the signal sensitivity are both considered, and high-reliability and high-precision touch interaction experience is achieved.

Description

Technical Field

[0001] The embodiments in this specification relate to the field of electronic technology, and in particular to touch signal detection circuits, touch signal detection methods, and touch position positioning methods. Background Technology

[0002] With the widespread application of flexible OLED display technology in devices such as smartphones, tablets, and laptops, its advantages of being thin, flexible, and having high image quality have significantly improved the user experience of end products. However, the ultra-thin structure of flexible OLEDs also brings new challenges, especially since the display driving signal generates strong common-mode interference through the parasitic capacitance between the OLED cathode and the touch sensor, which seriously affects the detection accuracy of capacitive touch and active pen signals.

[0003] Currently, the common approach to suppress interference is to reduce the signal gain of the touch detection circuit to avoid circuit saturation. However, this approach often weakens the effective touch signal while suppressing noise, resulting in a decrease in the signal-to-noise ratio, which makes it difficult to meet the requirements of high-precision touch interaction, especially under complex display screens. Summary of the Invention

[0004] In view of this, embodiments of this specification provide a touch signal detection circuit. One or more embodiments of this specification also relate to a touch signal detection method, a touch position positioning method, a touch device, and another touch device, to address the technical deficiencies existing in the prior art.

[0005] According to a first aspect of the embodiments of this specification, a touch signal detection circuit is provided, including an interference detection module, a touch detection module, a current replication module, and signal channels corresponding to each sensing unit; The interference detection module is connected to the reference signal channel and is used to detect the current in the reference signal channel to obtain the interference current. The reference signal channel can be any signal channel. The input end of the current replication module is connected to the interference detection module, and the output end is connected to the touch detection module. It is used to replicate the interference current and inject the replicated current into the touch detection module. The replicated current is in the opposite direction to the interference current. The touch detection module is also connected to other signal channels besides the reference signal channel for touch signal detection on the connected signal channels.

[0006] According to a second aspect of the embodiments of this specification, a touch signal detection method is provided, applied to a touch signal detection circuit. The touch signal detection circuit includes an interference detection module, a touch detection module, a current replication module, and signal channels corresponding to each sensing unit. The interference detection module is connected to a reference signal channel. The input terminal of the current replication module is connected to the interference detection module, and the output terminal is connected to the touch detection module. The touch detection module is also connected to other signal channels besides the reference signal channel. The method includes: The interference detection module detects the current in the reference signal channel to obtain the interference current; and sends the interference current to the current replication module, wherein the reference signal channel can be any signal channel. The current replication module replicates the interference current and injects the replicated current into the touch detection module. The replicated current is in the opposite direction to the interference current. The touch detection module detects touch signals on the connected signal channel based on the replicated current.

[0007] According to a third aspect of the embodiments of this specification, a touch position positioning method is provided, comprising: The touch signal detection result is obtained by the touch signal detection circuit based on the touch signal detection method. Based on the touch signal detection results, the touch position is located.

[0008] According to a fourth aspect of the embodiments of this specification, a touch device is provided, including a touch panel and a touch signal detection circuit.

[0009] According to a fifth aspect of the embodiments of this specification, another touch device is provided, including a touch component, a touch panel, and a touch signal detection circuit.

[0010] The touch signal detection circuit provided in one embodiment of this specification effectively suppresses the impact of common-mode display interference on the touch signal by introducing a collaborative mechanism between the interference detection module, the current replication module, and the touch detection module. Specifically, the interference detection module detects the interference current coupled from the OLED cathode in the reference signal channel; the current replication module accurately replicates this interference current and injects it into the touch detection module in the opposite direction. Since the interference current has high common-mode characteristics in each signal channel, the reverse-injected replicated current can approximately cancel out the interference current carried by the other signal channels in the touch detection module, thereby significantly reducing the common-mode noise component. At the same time, the touch detection module can still normally collect the effective touch signal in each connected signal channel (which is a differential-mode signal and is not affected by common-mode cancellation), ultimately improving the signal-to-noise ratio and detection accuracy of the touch signal without saturating the front-end charge amplifier. In summary, this solution achieves active compensation for display interference, balancing anti-interference capability and signal sensitivity, and realizing a highly reliable and high-precision touch interaction experience. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of a touch signal detection circuit provided in one embodiment of this specification; Figure 2 This is a schematic diagram illustrating the process of determining a reference signal channel according to one embodiment of this specification; Figure 3 This is a circuit diagram of a touch signal detection circuit provided in one embodiment of this specification; Figure 4 This is a circuit diagram of an interference detection module provided in one embodiment of this specification; Figure 5 This is a schematic diagram of a touch panel model provided in one embodiment of this specification; Figure 6 This is a circuit diagram of a touch detection module provided in one embodiment of this specification; Figure 7 This is a flowchart illustrating a touch signal detection method according to one embodiment of this specification; Figure 8 This is a flowchart illustrating a touch position positioning method according to one embodiment of this specification; Figure 9 This is a schematic diagram of the structure of a touch device provided in one embodiment of this specification; Figure 10 This is a schematic diagram of the structure of another touch device provided in one embodiment of this specification. Detailed Implementation

[0012] Many specific details are set forth in the following description to provide a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this specification. Therefore, this specification is not limited to the specific implementations disclosed below.

[0013] The terminology used in one or more embodiments of this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of one or more embodiments of this specification. The singular forms “a,” “described,” and “the” as used in one or more embodiments of this specification and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items. The term “at least one” as used in one or more embodiments of this specification means “one or more,” and “a plurality of” means “two or more.” The term “comprising” is an open-ended description and should be understood as “including but not limiting,” and may include other content in addition to what has been described.

[0014] It should be understood that although the terms first, second, etc., may be used to describe various information in one or more embodiments of this specification, such information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, first may also be referred to as second without departing from the scope of one or more embodiments of this specification, and similarly, second may also be referred to as first. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to a determination."

[0015] First, the terms and concepts used in one or more embodiments of this specification will be explained.

[0016] Flexible organic light-emitting diode (OLED): a self-emissive display device made using a flexible substrate (such as polyimide instead of traditional glass), whose structure can be bent, folded or even rolled up.

[0017] Active pen: A smart stylus with built-in power and electronic circuitry that can actively emit specific signals or communicate bidirectionally with the screen. It supports high-precision positioning, pressure sensitivity, tilt angle detection, and low-latency writing, and is widely used in professional drawing and note-taking scenarios.

[0018] Display interference refers to electromagnetic noise or voltage fluctuations (such as changes in cathode current, drive signal switching noise, etc.) generated during the operation of flexible OLED touch screens. These noises enter the touch sensor through parasitic capacitance or electromagnetic coupling, forming common-mode or differential-mode noise, which affects the accuracy of the touch signal and leads to problems such as decreased signal-to-noise ratio, false touches, or missed touches.

[0019] Touch electrodes (sensors): These are transparent electrode arrays integrated into touch panels to detect changes in capacitance caused by touch objects, such as fingers or styluses. They are typically made of conductive materials such as indium tin oxide or metal mesh. By crossing the transmitting (TX) and receiving (RX) electrodes to form sensing nodes, they convert external touch actions into electrical signals, thus realizing the core sensing element for position, pressure, and gesture recognition.

[0020] Parasitic capacitance refers to capacitance that exists naturally in electronic circuits or devices due to their physical structure and material properties, rather than being intentionally designed. It is not functionally required, but it can significantly impact circuit performance, especially in high-frequency, high-sensitivity, or highly integrated systems (such as flexible OLED touchscreens).

[0021] Common-mode noise refers to redundant interference signals that appear simultaneously and in phase at both input terminals of a circuit (or between a signal line and a reference ground). It does not carry effective information but raises the reference level of the entire signal. In capacitive touch systems, the driving noise of the OLED cathode is coupled to the touch electrode through parasitic capacitance. Since all channels are subjected to the same interference almost simultaneously, common-mode noise is formed, which can easily lead to saturation of the front-end amplifier, reduce the signal-to-noise ratio, and thus affect touch accuracy and stability.

[0022] A charge amplifier (CA) is a high-gain preamplifier circuit that converts weak charge signals into voltage signals, widely used in capacitive touch systems. Its core principle utilizes an operational amplifier and a feedback capacitor to form a transimpedance structure, integrating the input charge across the feedback capacitor and outputting a voltage proportional to it. Since the signals generated by touch sensors are extremely weak (typically femtocoulomb level), a CA can effectively amplify these signals for subsequent processing. However, when strong common-mode noise (such as interference from the OLED cathode) couples to the input, it can easily lead to output saturation, causing signal distortion and a decrease in the signal-to-noise ratio.

[0023] Signal-to-noise ratio (SNR) is a key indicator that measures the ratio of the strength of the useful signal to the level of background noise, usually expressed in decibels (dB). In touch systems, the higher the SNR, the clearer the effective touch signal generated by the touch, the less likely it is to be masked by interference, and the more stable and reliable the system response. Conversely, a lower SNR can easily lead to problems such as accidental touches, missed touches, or decreased sensitivity.

[0024] Signal gain refers to the amplification factor by which the front-end detection circuit (such as CA) amplifies the weak effective signal output from the touch electrodes. Its function is to boost the raw touch signal, which is in the microvolt to millivolt range, to a voltage range suitable for subsequent analog-to-digital conversion and digital processing. Higher signal gain helps improve system sensitivity and signal-to-noise ratio.

[0025] Common Electrode: This is a conductive layer shared by all pixels in a display panel, typically serving as the cathode in OLEDs. Its main function is to provide a uniform reference potential for each pixel to complete the current loop or electric field control. In OLEDs, when a data voltage is applied to the pixel anode, current flows from the anode through the light-emitting layer to the common cathode, thereby driving light emission. Because this electrode covers the display area and is extremely close to the touch sensor, it is susceptible to voltage fluctuations caused by rapid voltage jumps in the source line during display driving, becoming a major noise source coupled to the touch system.

[0026] Display Driver Integrated Circuit (DDIC): A special-purpose integrated circuit used to receive image data signals from a processor or graphics controller and convert them into timing and level signals required to control the brightness and color of the display screen pixels, thereby driving the screen to display images correctly.

[0027] Indium tin oxide (ITO) is a transparent conductive oxide material, typically composed of approximately 90% indium oxide and 10% tin oxide. Due to its excellent optical transparency and electrical conductivity, ITO is widely used in optoelectronic devices such as OLED displays, liquid crystal displays (LCDs), and touchscreens, serving as a transparent electrode or conductive layer. In OLEDs, ITO is often fabricated into a mesh structure to balance conductivity and light transmittance, while also reducing reliability issues caused by material brittleness.

[0028] An N-type metal-oxide-semiconductor (NMOS) is a type of metal-oxide-semiconductor field-effect transistor (MOSFET) based on an N-type semiconductor as the source and drain and a P-type substrate. When a sufficiently high positive voltage is applied to the gate, a conductive channel is formed on the surface of the P-type substrate, allowing electrons to flow from the source to the drain, thus conducting current. NMOS is commonly used in digital circuits as a pull-down network, offering advantages such as high carrier mobility and fast switching speed.

[0029] A P-type metal-oxide-semiconductor field-effect transistor (PMOS) is a MOSFET based on a P-type semiconductor as the source and drain, and an N-type substrate (or N-well). When a sufficiently low negative voltage is applied to the gate (relative to the source), a hole-conducting channel is formed on the surface of the N-type substrate, allowing current to flow from the source to the drain. PMOS is commonly used in pull-up networks in digital circuits, complementing NMOS to form a complementary metal-oxide-semiconductor (CMOS) structure, which features low static power consumption and strong noise immunity.

[0030] With the rapid development of flexible OLED display technology, it has been widely used in devices such as smartphones and tablets (PADs) due to its significant advantages such as thinness, flexibility, and high contrast. This new display structure not only enhances the appearance and interactive experience of terminal products, but also lays the foundation for future form innovations such as foldable and rollable displays.

[0031] However, while the ultra-thin physical structure of flexible OLEDs offers greater design freedom, it also poses significant challenges to integrated capacitive touch systems. Due to the substantial reduction in the overall thickness of the flexible OLED screen, the distance between the touch electrodes and the OLED cathode is significantly shortened, resulting in a larger parasitic capacitance between the two electrodes. This leads to a significant increase in the amount of display interference coupled from the OLED cathode through this parasitic capacitance. This increased parasitic capacitance makes it easier for high-frequency, high-amplitude voltage signals generated on the cathode during OLED display driving to "leak" to the touch sensing electrodes through capacitive coupling paths. The interference introduced by this coupling manifests as common-mode noise, directly superimposed on the weak touch signal. Current mainstream touch front-end detection circuits typically use charge converters (CAs) to extract charge changes on the sensor. When the common-mode noise amplitude is too large, the CA is prone to output saturation, causing its operating point to deviate from the linear region. Once saturation occurs, not only is the effective touch signal clipped or distorted, but subsequent demodulation and processing stages cannot accurately restore the original information, ultimately leading to a significant decrease in SNR and affecting touch accuracy and stability.

[0032] The aforementioned issues are not limited to finger touch control; they also severely impact the performance of capacitive active pens. As styluses become increasingly prevalent in drawing, annotation, and other scenarios, their requirements for signal purity and positioning accuracy are even higher. Noise coupling in OLED displays can cause handwriting jitter, response delays, and even false triggers, especially noticeable under high refresh rates or complex dynamic scenes.

[0033] To address these issues, traditional solutions typically employ a strategy of reducing the gain of the front-end signal. While this strategy can prevent output saturation to some extent and maintain the linear operating range of the circuit, it also compresses the amplitude of the effective touch signal, further deteriorating the overall signal-to-noise ratio. This is especially true in weak signal scenarios (such as fine pen tip operation or long-distance hovering), where touch sensitivity and reliability are significantly reduced.

[0034] To address the aforementioned issues, this specification provides an embodiment of a touch signal detection circuit applicable to an active pen touch system. The touch signal detection circuit includes an interference detection module, a touch detection module, a current replication module, and signal channels corresponding to each sensing unit. The interference detection module is connected to a reference signal channel and is used to detect the current in the reference signal channel to obtain an interference current. The reference signal channel can be any signal channel. The input terminal of the current replication module is connected to the interference detection module, and the output terminal is connected to the touch detection module. It is used to replicate the interference current and inject the replicated current into the touch detection module, wherein the replicated current is in the opposite direction to the interference current. The touch detection module is also connected to other signal channels besides the reference signal channel for touch signal detection on the connected signal channels.

[0035] It is worth noting that when this circuit is used in an active pen touch system, it utilizes one or more touch electrodes as reference signal channels. The interference detection module extracts the display interference current coupled to the reference signal channel from the OLED cathode via parasitic capacitance. This interference current is fed into the current replication module, generating a replication current in the opposite direction, which is then synchronously injected into the front-end detection nodes (i.e., the touch detection modules) of all other signal channels. Since the display noise caused by the flexible OLED exhibits high common-mode characteristics on each touch electrode, the reverse-injected replication current can effectively and approximately cancel out the common-mode interference at the input of the touch detection module, thereby significantly reducing the impact of the display driving signal on the touch front end. Thanks to this, the output of the touch detection module avoids saturation and nonlinear distortion caused by strong common-mode interference while retaining a sufficiently large effective active pen signal. The subsequent demodulation circuit can also accurately recover key information such as the active pen's position, pressure, and hovering based on this, significantly improving the signal-to-noise ratio and accuracy of active pen detection. In summary, by employing a hardware-level active interference cancellation mechanism, the electromagnetic compatibility challenges posed by the ultra-thin structure of flexible OLEDs are fundamentally alleviated, achieving a highly reliable and precise active pen interaction experience without sacrificing gain and sensitivity.

[0036] This specification provides a touch signal detection circuit, and also relates to a touch signal detection method, a touch position positioning method, a touch device, and another touch device, which will be described in detail in the following embodiments.

[0037] See Figure 1 , Figure 1 This specification shows a schematic diagram of a touch signal detection circuit according to an embodiment of the present specification. The touch signal detection circuit includes an interference detection module 100, a touch detection module 200, a current replication module 300, and a signal channel 400 corresponding to each sensing unit. The interference detection module 100 is connected to the reference signal channel 402 and is used to detect the current in the reference signal channel 402 to obtain the interference current. The reference signal channel 402 can be any signal channel. The input terminal of the current copying module 300 is connected to the interference detection module 100, and the output terminal is connected to the touch detection module 200. It is used to copy the interference current and inject the copied current into the touch detection module 200. The direction of the copied current is opposite to that of the interference current. The touch detection module 200 is also connected to other signal channels 404 besides the reference signal channel 402, and is used to detect touch signals on the connected signal channels 404.

[0038] It should be noted that a touch signal detection circuit refers to an analog front-end circuit system used to detect capacitance changes caused by a user's finger or stylus operating on the touchscreen and convert them into a processable electrical signal. Through a touch signal detection circuit, high-precision, high signal-to-noise ratio touch signal acquisition can be achieved. For example, the touch signal detection circuit can be an analog front-end module integrated into the main control chip of the touch device; or it can be a capacitance detection front-end within a separate touch chip.

[0039] An interference detection module is a sub-circuit used to extract interference current caused by display noise from a reference signal channel. The interference detection module can sense the common-mode interference components coupled from the OLED cathode to the touch electrodes and convert the interference voltage signal into a current signal. For example, the interference detection module can be a high-bandwidth current-sense amplifier connected to the reference signal channel; or it can be a dedicated transimpedance amplifier connected to an RX signal channel at the edge of the screen to sample the OLED noise current.

[0040] A touch detection module is a core detection unit (usually including a charge amplifier) ​​used to effectively acquire and amplify touch signals from all signal channels except the reference signal channel. The touch detection module is a key module in the touch signal detection circuit; its linearity and dynamic range affect touch performance. Through the touch detection module, weak capacitance change signals caused by touch operations can be extracted and output for subsequent demodulation processing. For example, the touch detection module can be an integrated multi-input charge amplifier array, each corresponding to an RX signal channel; or it can be a CA architecture supporting differential input, where one end receives the sensing signal and the other end receives a replica current for cancellation.

[0041] A current replication module is a circuit unit that receives the interference current signal output by the interference detection module and generates a replicated current with the same amplitude but opposite direction. Current replication modules are typically based on current mirror units or transconductance amplifier structures, possessing high matching accuracy and bandwidth. They can achieve mirror-image inversion of the interference current, preparing for cancellation. For example, a current replication module can be a wideband current mirror array; it can also be a multi-signal channel parallel replication structure, generating a corresponding replicated current for each RX signal channel to achieve channel-level cancellation.

[0042] A sensing unit is a physical or electrical functional unit in a touch panel used to sense changes in capacitance. It typically consists of an electrode structure made of transparent conductive materials (such as indium tin oxide, silver nanowires, or metal mesh). As the sensing front end for interaction between the touch system and the user, the sensing unit changes the electric field distribution around it when a finger or stylus approaches, causing a change in its capacitance to ground or to the driving electrode. This minute change in capacitance can be detected by subsequent circuitry and converted into position or pressure information.

[0043] A signal channel refers to an independent analog signal path corresponding to each sensing unit. It is used to transmit current / charge signals from a single sensing unit to an interference detection module or touch detection module, or to transmit excitation signals to the sensing unit. In practical applications, the same signal channel can be reused in different operating phases (such as the display refresh phase and the touch scanning phase). For example, it can be used as a reference signal channel to extract interference current for a portion of the time, and as a normal signal channel for normal touch or pen signal detection for the rest of the time. A touchscreen typically has dozens to hundreds of signal channels, corresponding to horizontal or vertical electrodes. For example, a 10×15 touch panel has 15 RX signal channels and 10 TX signal channels.

[0044] A reference signal channel refers to one or more signal channels used for monitoring interference rather than main touch detection. The reference signal channel shares the same display noise environment as other signal channels, and therefore can serve as a sampling source for providing interference current. In practical applications, any normally functioning signal channel can be dynamically selected temporarily as the reference signal channel; for example, a signal channel not covered by a finger or stylus can be randomly selected as the reference signal channel to improve robustness. Alternatively, an edge or dedicated signal channel can be fixed as the reference signal channel; for example, the outermost RX electrode can be fixed as the reference signal channel, as it is far from the user's operating area and less affected by touch.

[0045] Interference current refers to the undesirable current coupled from the OLED common electrode (such as the cathode) to the touch electrode through parasitic capacitance, mainly caused by the display drive signal. Interference current does not contain valid touch information, but it is superimposed on the real touch signal, causing detection distortion, and therefore needs to be canceled. For example, when the OLED refresh rate is 120Hz, the current sensed on the touch electrode at 120Hz and its harmonic components is interference current.

[0046] The replicated current refers to a compensation current generated by the current replication module, which has the same amplitude as the interference current but opposite direction. The replicated current is injected into the touch detection module to cancel out the interference current. For example, if the interference current is +10nA, the replicated current will be -10nA.

[0047] The solution described in this specification effectively suppresses the impact of common-mode display interference on touch signals by introducing a collaborative mechanism between the interference detection module, the current replication module, and the touch detection module. The interference detection module detects the interference current coupled from the OLED cathode in the reference signal channel; the current replication module accurately replicates this interference current and injects it into the touch detection module in the opposite direction. Since the interference current has high common-mode characteristics in each signal channel, this reverse-injected replicated current can approximately cancel out the interference current carried by the other signal channels in the touch detection module, thereby significantly reducing common-mode noise components. Simultaneously, the touch detection module can still normally acquire the effective touch signals in each connected signal channel, ultimately improving the signal-to-noise ratio and detection accuracy of the touch signal while avoiding saturation of the front-end charge amplifier.

[0048] In one optional embodiment of this specification, the touch signal detection circuit further includes a switching module; The input terminal of the switching module is connected to the signal channel, the first output terminal is connected to the interference detection module, and the second output terminal is connected to the touch detection module. The switching module is used to connect the signal channel to the interference detection module or the touch detection module.

[0049] It should be noted that the switching module is a programmable or time-controlled analog switch circuit used to dynamically select whether to connect a signal channel to the interference detection module or the touch detection module. For example, the switching module can be a circuit unit composed of a set of controlled analog switches, with each sensing unit corresponding to two independent switches, controlling the signal flow to either the touch detection module or the interference detection module respectively. The switching module ensures that only one switch is active at any given time, enabling flexible switching between "noise sampling mode" and "touch detection mode" for the sensing unit, improving resource utilization efficiency and anti-interference capabilities.

[0050] The first output terminal refers to the switch output terminal in the switching module connected to the interference signal detection module. The second output terminal refers to the switch output terminal in the switching module connected to the touch detection module. The first and second output terminals will not be turned on simultaneously to avoid the input of the touch detection module being loaded by the interference detection path. The first and second output terminals will also not be turned off simultaneously (usually designed for seamless switching) to prevent the touch electrodes from floating and introducing additional noise. Based on this, when the switching module connects the interference detection module to the reference signal channel, the interference detection module can sample the interference current; when the switching module disconnects the touch detection module from the reference signal channel, the interference current in the reference signal channel will not affect the main signal path in the touch detection module.

[0051] For example, each touch electrode is connected to two switches, one of which is connected to the touch detection module, and the other is connected to the interference detection module. The two switches are not turned on at the same time. Assume that the touch electrode RX[M] is connected to the interference detection module, and RX[M] is defined as the reference signal channel. The interference voltage signal of the common electrode is Vc. The interference current Ic generated by the interference signal through the parasitic capacitance Cp can be calculated by the following formula (1), where s represents the Laplace variable, which is obtained based on the complex frequency j and the angular frequency ω: (1) The current replication module replicates the interference current Ic and sends the replicated current Ic' to the touch detection module of each touch electrode. For signal channels other than the reference signal channel, the interference current Ip caused by the common electrode through Cp and the replicated current Ic' cancel each other out at the input of the touch detection module. The interference current of the common electrode does not flow into the touch detection module; only the touch signal enters the touch detection module, thereby improving the sensitivity of the touch signal. For the reference signal channel, since the touch detection module only connects to the replicated current Ic', the reference signal channel detects the interference signal. The detection value of the reference signal channel can be used as a screen noise detection signal, providing screen noise interference signal information and auxiliary information for software processing.

[0052] The solution implemented in this specification, through the introduction of a switching module, achieves dynamic switching between the interference detection module and the touch detection module. During a specific timing window (such as a display driving time slot), the switching module temporarily connects one or more reference signal channels to the interference detection module, accurately capturing the interference current in the current OLED operating state. Subsequently, the current replication module generates a reversed replication current and injects it into the front end of the touch detection module, actively canceling out similar interference in other signal channels. Because the reference signal channels can be dynamically rotated, it accurately tracks display noise that changes with the screen content while avoiding the need for dedicated reference electrodes to occupy valuable screen space. Ultimately, without reducing the front-end gain, it effectively prevents charge amplifier saturation, ensuring the integrity and linearity of the weak downward signal from the active pen, and significantly improving the signal-to-noise ratio and detection accuracy of pen touch.

[0053] In one optional embodiment of this specification, the touch signal detection circuit further includes a control module; The output of the control module is connected to the switching module, which is used to control the switching module to connect the reference signal channel to the interference detection module when an interference signal is detected.

[0054] It should be noted that the control module refers to a digital or mixed-signal logic unit used to monitor the system status and generate control signals for the switching module. When strong display interference is detected or noise needs to be updated, the control module can dynamically trigger the control signal of the switching module, controlling the switching module to connect the reference signal channel to the interference detection module to collect the current interference current. The control module can operate based on various signals, such as OLED frame synchronization signals, screen content change indicators, CA output near saturation warnings, or specific time slots in the active pen communication protocol. The control module can ensure that interference sampling is performed within an effective time window to avoid affecting normal touch performance. For example, the control module can initiate an interference sampling process once the CA output amplitude exceeds a threshold; it can also reserve a "noise calibration slot" before the active pen downlink communication cycle, with the control module controlling the switching module to connect the reference signal channel to the interference detection module. The switching module receives control signals from the control module and performs physical switch on / off operations to achieve dynamic switching between the interference detection module and the touch detection module.

[0055] The solution implemented in this specification, through the introduction of a control module, achieves intelligent scheduling of the interference signal sampling process: when interference signals are detected, OLED display interference increases (such as high-brightness screen switching, frame rate changes), or the touch front end approaches saturation, the control module immediately drives the switching module to temporarily connect the reference signal channel to the interference detection module, accurately capturing the current common-mode interference current. The entire process is triggered on demand and time-division multiplexed by the control module, avoiding resource waste from continuous sampling and ensuring that the noise model always matches the current display state. Ultimately, without sacrificing gain and bandwidth, CA saturation is effectively prevented, ensuring linear transmission and high-fidelity demodulation of the weak downlink signal from the active pen, significantly improving the signal-to-noise ratio, positioning accuracy, and anti-interference robustness of pen touch control.

[0056] In one optional embodiment of this specification, the input terminal of the control module is connected to the sensing unit and is further configured to determine a reference signal channel from a pre-set candidate signal channel in response to a touch signal from the sensing unit, wherein the sensing unit corresponding to the reference signal channel is different from the sensing unit corresponding to the touch signal.

[0057] It should be noted that the control module responds to touch signals from the sensing unit (such as capacitance changes caused by a finger or stylus). Based on the touch position information, it excludes touch-occupied signal channels from a preset set of candidate signal channels and intelligently selects one or more unaffected candidate signal channels as reference signal channels for interference current sampling. For example, when a stylus signal is detected in RX signal channels 5 to 8, it automatically selects one signal channel from the edge signal channels {1, 2, 15, 16} as the reference signal channel.

[0058] Touch signals are electrical signals corresponding to changes in effective capacitance caused by the proximity of a finger or stylus, reflecting the user's interaction intent. Touch signals are typically manifested as differential-mode signals at a specific frequency or encoding, distinct from the common-mode interference generated by OLEDs. For example, a touch signal could be a weak current induced at the RX terminal by a 200kHz sine wave emitted by the stylus.

[0059] A candidate signal channel refers to a pre-configured set of signal channels that can be used as a reference signal channel. Candidate signal channels provide the control module with a range of selectable reference signal channels. In practical applications, candidate signal channels that are at the edge, have low usage, or no touch signals are typically selected as reference signal channels to reduce the probability of being covered by touch.

[0060] By applying the scheme of the embodiments in this specification, the control module monitors the touch signals of the sensing units and realizes intelligent and obstacle-avoiding selection of the reference signal channel: when the user is detected to be operating with a finger or pen in certain areas, the control module immediately identifies these occupied sensing units and excludes them from the pre-set candidate signal channels, and instead selects a candidate signal channel that is far away from the touch area and is not contaminated by effective signals as the reference signal channel, so as to ensure accurate noise estimation of the reference signal channel and significant cancellation effect.

[0061] For example, the reference signal channel is preferably a signal channel for which no active pen signal is currently detected. Specifically, the selection of the reference signal channel is not limited by the electrode orientation; it can be selected from sensing electrodes in the touch detection direction (e.g., the RX signal channel used to receive signals in a mutual capacitance architecture) or driving electrodes in the non-detection direction (e.g., the TX signal channel used to transmit excitation signals). That is, one or more signal channels not activated by the pen signal can be dynamically selected as reference signal channels from all available TX and RX sensing units. Furthermore, the reference signal channel is not fixed but updated as the active pen moves: when the active pen moves to different areas of the screen, the control module can automatically avoid signal channels covered or adjacent to the pen based on the latest touch / pen signal distribution, and reselect a TX or RX signal channel that is far from the pen tip and has a clean signal as the new reference signal channel. This dynamic switching mechanism ensures the accuracy and robustness of interference sampling, effectively avoids the pen signal being mistakenly introduced into noise estimation, thereby improving the accuracy of common-mode interference cancellation and the overall signal-to-noise ratio of the system.

[0062] See Figure 2 , Figure 2 This specification illustrates a process for determining a reference signal channel according to an embodiment, specifically including the following steps: Step 202: Pre-set multiple candidate signal channels, such as setting RX10 and RX20 as candidate signal channels.

[0063] Step 204: Randomly select any candidate signal channel as the reference signal channel, such as selecting RX10 as the reference signal channel.

[0064] Step 206: Detect the position coordinates of the active pen to determine whether the position of the active pen falls on RX10.

[0065] If not, proceed to step 208; if yes, proceed to step 210.

[0066] Step 208: Continue to use RX10 as the reference signal channel.

[0067] Step 210: Switch the reference signal channel to RX20.

[0068] Applying the scheme of the embodiments in this specification, after randomly selecting a candidate signal channel (such as RX10) as the reference signal channel, the position coordinates of the active pen are detected. If the active pen is located in the coverage area of ​​the reference signal channel, it is determined that it may contaminate the reference signal channel, thereby triggering the reference signal channel to switch to another candidate signal channel (such as RX20). Conversely, if the active pen is not in the area, the current reference signal channel is used for interference sampling. This intelligent decision-making mechanism based on the active pen position avoids the noise estimation distortion problem caused by the reference signal channel being occupied by touch, ensuring that the interference current always comes from a "clean" signal channel, thereby achieving more accurate common-mode interference cancellation. Ultimately, without increasing hardware complexity, the signal-to-noise ratio, positioning accuracy, and system robustness of the active pen signal in flexible OLED devices are significantly improved.

[0069] In one optional embodiment of this specification, the current replication module includes multiple current mirror units connected in parallel, and the touch detection module includes multiple touch detection sub-modules, with different touch detection sub-modules connected to different signal channels. Each current mirror unit has its input connected to a reference signal channel and its output connected to any touch detection submodule. Different current mirror units are connected to different touch detection submodules.

[0070] It should be noted that the touch detection module consists of multiple independent touch detection sub-modules. This modular design facilitates channel-level optimization and parallel processing of the touch detection module, making it particularly suitable for active pen systems with a high number of channels. The number of touch detection sub-modules typically corresponds to the number of signal channels. For example, assuming there is one reference signal channel and three other signal channels, there would be four touch detection sub-modules, each corresponding to one reference signal channel and one of the three other signal channels.

[0071] The touch detection submodule is an independent detection unit in the touch detection module. It corresponds to a specific signal channel (such as a certain RX electrode), and can receive touch signals from the corresponding sensing unit and superimpose the replicated current from the corresponding current mirror unit to achieve common-mode cancellation at the input.

[0072] A current mirror unit is a basic functional unit in the current replication module, consisting of at least two matched transistors, which can mirror the input current proportionally (e.g., 1:1). Each current mirror unit in the current replication module operates independently, and a parallel structure supports synchronous compensation for multiple signal channels. Multiple current mirror units share the interference current of the reference signal channel, but each drives a different touch detection submodule.

[0073] Using the scheme in the embodiments of this specification, although the noise generated by the OLED cathode is essentially common-mode, the parasitic capacitance between the sensing electrodes (such as TX or RX) and the cathode is not exactly the same due to differences in the position, trace length, and surrounding structure of each sensing electrode in the screen. Therefore, the actual interference current coupled to each signal channel will have slight deviations in amplitude and phase. If a single replicated current is used to uniformly cancel all signal channels, it is difficult to achieve high-precision compensation. To this end, in the embodiments of this specification, multiple parallel current mirror units are set up. They share the interference current extracted from the same reference signal channel as input, but each current mirror unit independently outputs a replicated current and accurately injects it into the front end of the touch detection submodule paired with it. In this way, each signal channel corresponds to a reverse compensation current that highly matches its own interference characteristics, thereby achieving efficient common-mode cancellation at the analog front end. This "one channel, one mirror" architecture utilizes the common-mode characteristics of interference while taking into account the individual differences between signal channels. It effectively prevents CA saturation without sacrificing gain, significantly improving the linearity, integrity, and signal-to-noise ratio of the active pen signal. It is particularly suitable for flexible OLED devices with high refresh rates and high-precision handwriting interaction.

[0074] In one optional embodiment of this specification, the signal channel includes parasitic capacitance. Different signal channels have parasitic capacitances connected to different current mirror units. The parasitic capacitance of the reference signal channel is connected to a first current mirror unit, and the parasitic capacitances in other signal channels besides the reference signal channel are connected to a second current mirror unit. The first current mirror unit is any one of the current mirror units, and the second current mirror unit is any current mirror unit other than the first current mirror unit. The current replication module is used to replicate the interference current based on the parasitic capacitance to obtain the replicated current.

[0075] In practical applications, since the parasitic capacitance Cp of each touch electrode to the common electrode is not consistent, the replication current of each signal channel can be adjusted by adjusting the replication ratio to match the size of the parasitic capacitance Cp, so that interference currents are canceled out as much as possible. For example, assuming that the Cp of the reference signal channel RX10 is 300pF and the Cp of the signal channel RX1 is 280pF, then the current replication ratio of the current mirror unit corresponding to the signal channel RX1 in the current replication module is 280 / 300; assuming that the Cp of RX2 is 250pF, then the current replication ratio of the current mirror unit corresponding to the signal channel RX2 in the current replication module is 250 / 300, and so on. This ensures that the touch detection module only responds to the real touch signal, greatly improving touch sensitivity and stability.

[0076] By applying the scheme of the embodiments in this specification, the parasitic capacitance of each signal channel is precisely matched with the replication ratio of the corresponding current mirror unit, so that the amplitude of the generated replication current is highly consistent with the actual interference current coupled in by its local parasitic capacitance. Since the magnitude of the interference current is proportional to the parasitic capacitance of each signal channel, this scaling mechanism ensures that the reverse-injected replication current can accurately cancel the common-mode noise of each signal channel, thereby achieving efficient and balanced interference suppression.

[0077] See Figure 3 , Figure 3This specification illustrates a circuit diagram of a touch signal detection circuit according to one embodiment. This touch signal detection circuit is an active interference cancellation capacitive touch front-end architecture for flexible OLED display environments. Its core function is to suppress common-mode interference current coupled from a common electrode (such as an OLED cathode) to each signal channel, thereby improving the signal-to-noise ratio and detection accuracy of the touch signal. The touch signal detection circuit mainly includes the following parts: On the left side are multiple sensing units (RX1 to RXN) in the touch panel (Pannel). Each RX is coupled to the common electrode Vc through parasitic capacitances (Cp1 to CpN). At the same time, each RX switches the signal path through two switches (e.g., RX1 is connected to the touch detection module or interference detection module through SW1_1 and SW1_2; RX2 is connected to the touch detection module or interference detection module through SW2_1 and SW2_2; RXN is connected to the touch detection module or interference detection module through SWN_1 and SWN_2, etc.). Any RX signal channel can be used as a reference signal channel, and its coupled interference current Ic is sent to the interference detection module for sampling via a dedicated path. The interference detection module is implemented using a bias amplifier consisting of a reference voltage (VR) and a direct current (DC) voltage source. After acquiring the interference current, the interference detection module inputs it to the current replication module (composed of multiple parallel current mirror units). The current replication module replicates the interference current to obtain a replicated current, which is then injected into the input terminals of their respective touch detection submodules. Simultaneously, the RX signal of the non-reference signal channel is connected to the corresponding touch detection submodule via SW_N_2 to acquire valid touch signals. Because the interference current has common-mode characteristics in all signal channels, and the replicated current is in the opposite direction to the interference current, efficient cancellation can be achieved at the analog front end. This avoids the sensitivity reduction problem caused by gain reduction in traditional solutions, significantly improving the system's anti-interference capability and positioning stability on high-brightness, high-refresh-rate OLED screens.

[0078] See Figure 4 , Figure 4The circuit diagram of an interference detection module provided in one embodiment of this specification is shown. The core function of the interference detection module is to perform high-precision sampling and amplification of the OLED common-mode interference current coupled from the reference signal channel (such as a certain RX electrode), and to provide a stable reference input for the subsequent current replication module. The interference detection module uses a differential input, common-source, common-gate transconductance amplifier (OTA) as the main amplification unit. Its input terminal is connected to the interference current path of the reference signal channel, and current-to-voltage conversion is achieved through a differential pair composed of NMOS and PMOS. The tail current source or bias branch of the differential pair is set by the reference current provided by the reference (REF) node. The input bias is provided by the VR source on the left to ensure that the amplifier operates in a suitable linear region. The output terminal replicates the amplified interference signal into multiple equal-amplitude, in-phase output currents IOUT[1] to IOUT[N] through a multi-stage common-source, common-gate current mirror structure, which are respectively sent to the current mirror unit of each touch detection submodule. The entire circuit design features high gain, low noise, and high common-mode rejection ratio. It can accurately extract weak interference currents in the context of strong display noise, providing a high-quality reference signal for the subsequent active cancellation mechanism, thereby effectively improving the anti-interference capability and positioning accuracy of the touch system in flexible OLED devices.

[0079] See Figure 5 , Figure 5 This diagram illustrates a 4x4 touch panel model provided in one embodiment of this specification. The model consists of a grid structure formed by four horizontal electrodes (TX1 to TX4) and four vertical electrodes (RX1 to RX4), with each intersection forming a mutual capacitance unit. When the stylus approaches a certain area, the signal emitted by the stylus is transmitted to the touch electrodes through the parasitic capacitance between the stylus and the panel. The signals emitted by the stylus include those emitted from the stylus tip, stylus ring, and stylus tail. The touch electrodes include TX touch electrodes in the X direction and RX touch electrodes in the Y direction. The stylus conductor tip can alter the local electric field distribution, causing a change in the mutual capacitance between adjacent TX and RX electrodes, thereby generating a detectable signal response. Simultaneously, each TX and RX electrode has a parasitic capacitance Cp to the common ground, representing the coupling path of the OLED cathode or other interference sources, which may introduce common-mode noise in high refresh rate display environments. By measuring the capacitance changes between each TX-RX signal channel and combining the signal strength with spatial distribution, the touch panel model can achieve precise positioning of the stylus.

[0080] See Figure 6 , Figure 6This specification illustrates a circuit diagram of a touch detection module according to one embodiment, used to receive and process downlink signals from an active pen. Here, Vtx_pen represents the pen signal (typically a square wave or sine wave) emitted by the active pen, coupled to the sensing node of the touch panel via capacitor Cpen; Cp represents the parasitic capacitance between this node and a common electrode (such as an OLED cathode), which introduces display driving noise; VREF is the internal reference voltage of the touch detection module, applied to the non-inverting input of the operational amplifier as a virtual ground reference point. The touch detection module includes resistor Rf and capacitor Cf for integrating the charge signal and suppressing low-frequency drift; when the active pen approaches, the charge change on Cpen is injected into the input of the operational amplifier, amplified, and forms a voltage response proportional to the pen signal at the output Vout. The touch detection module achieves high gain and high linearity detection of weak pen signals, while also possessing a certain common-mode interference suppression capability, making it a key front-end circuit for achieving high-precision active pen positioning.

[0081] For example, Vtx_pen is converted into current after passing through Cpen. The current flows through Rf and Cf, and the resulting voltage Vout can be calculated using the following formulas (2) and (3): (2) (3) At the frequency of the active pen's transmitted signal, take Rf such that Rf*Cf*ω 1.

[0082] The amplitude of the Vout signal can be calculated using the following formula (4): (4) When the stylus approaches the panel, the size of Cpen changes. Since the amplitude of Vout is linearly related to the size of Cpen, the size of Cpen can be detected by detecting the amplitude of Vout. When Cpen increases, it indicates that a stylus is approaching this touch electrode; when Cpen is 0, it indicates that no stylus is approaching this touch electrode. By detecting the size of Cpen on each touch electrode, the position of the stylus can be located.

[0083] Because the touch electrodes and the common electrode of the display on the panel form a relatively large parasitic capacitance Cp, when the DDIC drives the panel to display the image, the pixel driving signal source line affects the OLED cathode, causing voltage fluctuations on the OLED cathode. These voltage fluctuations are conducted to the receiver of the touch detection module through the parasitic capacitance Cp, interfering with the detection of the pen signal. This results in inaccurate pen position coordinates, and the interference signal can even cause the CA output to saturate, making it impossible to detect the pen signal. The touch signal detection circuit proposed in the embodiments of this specification can eliminate the influence of display interference on the touch electrodes, thereby improving the detection accuracy of the pen signal.

[0084] See Figure 7 , Figure 7 This document illustrates a flowchart of a touch signal detection method according to an embodiment of this specification. The method is applied to a touch signal detection circuit, which includes an interference detection module, a touch detection module, a current replication module, and signal channels corresponding to each sensing unit. The interference detection module is connected to a reference signal channel. The input terminal of the current replication module is connected to the interference detection module, and its output terminal is connected to the touch detection module. The touch detection module is also connected to other signal channels besides the reference signal channel. The method specifically includes the following steps: Step 702: The interference detection module performs current detection on the reference signal channel to obtain the interference current; and sends the interference current to the current replication module, wherein the reference signal channel is any signal channel.

[0085] Step 704: The current copying module copies the interference current and injects the copied current into the touch detection module, wherein the copied current is in the opposite direction to the interference current.

[0086] Step 706: The touch detection module performs touch signal detection on the connected signal channel based on the replicated current.

[0087] It should be noted that the implementation methods of steps 702 to 706 are the same as those of each module in the above-mentioned touch signal detection circuit, and will not be described again in the embodiments of this specification.

[0088] Applying the scheme of the embodiments in this specification, firstly, the interference detection module samples the interference current coupled from the OLED common electrode through parasitic capacitance in the reference signal channel; then, the current replication module accurately replicates the interference current and generates a replicated current in the opposite direction, injecting it into the input terminal of the touch detection module; since OLED interference has high common-mode characteristics in each signal channel, this replicated current can approximately cancel out the interference current coupled from other signal channels at the front end of the touch detection module, thereby significantly reducing the common-mode noise component; based on this, the touch detection module performs high-gain, linearized detection on the remaining effective touch signal, which avoids the signal-to-noise ratio degradation caused by reduced gain in traditional schemes, and also prevents the charge amplifier from saturating and distorting due to strong interference. Ultimately, this method can significantly improve the signal-to-noise ratio, detection sensitivity, and anti-display interference capability of touch, especially high-precision active pen interaction, without increasing system complexity.

[0089] See Figure 8 , Figure 8 This specification shows a flowchart of a touch position positioning method according to an embodiment, which specifically includes the following steps: Step 802: Obtain the touch signal detection result, wherein the touch signal detection result is obtained by the touch signal detection circuit based on the touch signal detection method.

[0090] Step 804: Locate the touch position based on the touch signal detection results.

[0091] It should be noted that the touch signal detection result refers to the signal data output after suppressing common-mode noise following the application of the aforementioned touch signal detection method. The touch signal detection result can serve as the raw input to the positioning algorithm, reflecting the net capacitance change on each sensing unit (such as the RX electrode) caused by touch. Ideally, the touch signal detection result contains only valid touch / pen signals, without any spurious components introduced by the OLED driver, ensuring reliable subsequent positioning.

[0092] Touch position refers to the specific location of the operation point in the screen coordinate system when a user operates on the touch panel with their finger or stylus, usually represented by two-dimensional coordinates (X, Y). Further, Z-axis (pressure / hover height) or angle information can also be provided. Touch position serves as core input data for human-computer interaction, driving operations such as cursor movement, clicking, writing, and gesture recognition, acting as a bridge between the operating system, applications, and user intent. In the embodiments of this specification, the touch position is not directly measured, but calculated based on the touch signal detection results determined by the touch signal detection circuit and then processed by a positioning algorithm (such as the centroid method, interpolation method, neural network regression method, etc.). For example, when a user clicks the "send" button on a smartphone, the identified touch position is (X=320, Y=680) (unit: pixels); when a user draws a line on a tablet with a stylus, a series of high-precision coordinate points are continuously output, such as (150.3, 420.7), (152.1, 421.5), etc.

[0093] In practical applications, there are multiple ways to locate the touch position based on the touch signal detection results. The specific method chosen depends on the actual situation, and this specification does not impose any limitations on this approach. One possible implementation of this specification is to determine the touch position by calculating the weighted average position of the touch signal detection results on multiple adjacent signal channels using the centroid method. For example, the signal amplitude can be used as the weight to perform a weighted summation and normalization of the signal channel indices to obtain the touch position coordinates. Another possible implementation of this specification is to use a neural network regression method. A regression model (such as a multilayer perceptron, convolutional neural network, or lightweight decision tree) is trained using a large amount of labeled data (touch position and corresponding touch signal detection results). The obtained touch signal detection results are then input into the trained regression model to obtain the touch position coordinates output by the trained regression model.

[0094] The solution implemented in this specification first obtains a high-quality touch signal detection result after active cancellation of common-mode interference. This touch signal detection result significantly suppresses the coupling noise of the flexible OLED cathode due to the front-end current replication and reverse injection mechanism, avoiding charge amplifier saturation and signal distortion. Subsequently, based on the touch signal detection result, the true physical position of the finger or active pen is accurately reconstructed. Because the signal-to-noise ratio and linearity of the touch signal detection result are greatly improved, stable, low-jitter, and high-resolution touch position output can still be achieved even under high refresh rates and complex dynamic scenes. This is particularly suitable for high-end active pen applications such as drawing tablets and 2-in-1 laptops where writing accuracy is critical.

[0095] See Figure 9 , Figure 9This specification shows a schematic diagram of a touch device 900 provided in one embodiment, which includes a touch panel 902 and a touch signal detection circuit 904.

[0096] It should be noted that touch devices are electronic devices that can sense a user's touch or proximity to a surface using their finger or a stylus, and convert this action into electrical signals or digital commands. Touch devices serve as the core input interface for human-computer interaction and are widely used in scenarios such as information input, gesture control, and handwritten annotation. Examples of touch devices include smartphones, tablets, 2-in-1 laptops, graphics displays, and in-vehicle infotainment screens.

[0097] A touch panel is a sensor layer integrating multiple sensing units (such as TX / RX electrodes) to sense changes in electric field or capacitance caused by an external conductor (finger / active pen). The touch panel acts as the "sensory skin" of a touch device, directly interacting with the user and generating raw analog signals. Touch panels can be implemented using different technologies, such as surface capacitive and projected capacitive. In flexible OLED devices, the touch panel is often integrated with the display pixel layer to achieve an ultra-thin structure. For example, the touch panel can be an ITO mesh layer covering the OLED display, containing 48 RX and 32 TX electrodes.

[0098] By applying the solutions described in the embodiments of this specification, in touch devices, the severe impact of flexible OLED display noise on touch performance is effectively solved by tightly integrating the touch panel with a touch signal detection circuit that has active interference suppression capabilities. The touch panel is responsible for high-density acquisition of capacitance change signals caused by fingers or active pens, while the touch signal detection circuit uses a reference signal channel to extract the common-mode interference current coupled to the OLED cathode, and achieves channel-level noise cancellation at the front end of the touch detection module through current replication and reverse injection mechanisms. This allows for stable output of high signal-to-noise ratio touch signal detection results even under high refresh rates and complex dynamic scenes, significantly improving the user's interactive experience in scenarios such as writing, drawing, and multi-touch.

[0099] The above is a schematic representation of a touch device according to this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the touch signal detection circuit described above belong to the same concept. Details not described in detail in the technical solution of the touch device can be found in the description of the technical solution of the touch signal detection circuit described above.

[0100] See Figure 10 , Figure 10 This specification shows a schematic diagram of another touch device provided in one embodiment. The touch device 1000 includes a touch component 1002, a touch panel 1004, and a touch signal detection circuit 1006.

[0101] It's important to note that touch components refer to functional hardware units involved in the touch interaction process. They can emit downlink signals of specific frequencies, codes, or phases to the touch panel for identification, demodulation, and precise positioning. As active input devices, touch components can provide interactive capabilities far exceeding passive touch (such as fingers), including sub-millimeter-level positioning, multi-level pressure sensitivity, hover detection, tilt recognition, button commands, and low-latency writing. The emitted downlink signals typically operate in the hundreds of kHz to several MHz frequency band, can be captured by the sensor electrode array of the touch panel, and demodulated and restored by the back-end touch signal detection circuit, thereby achieving high-precision bidirectional collaborative human-computer interaction. Examples of touch components include universal active pens, active pens that can pair with touch devices via Bluetooth, and active pens with built-in resonant circuits or active driver chips.

[0102] Using the solutions described in this specification, the touch component can actively emit downlink signals of a specific frequency, encoding, or phase. These downlink signals are efficiently captured by the sensor electrode array of the touch panel and then amplified with low noise, suppressed by interference (such as OLED common-mode noise cancellation), and demodulated synchronously by the touch signal detection circuit. This accurately restores multi-dimensional information such as the position, pressure, tilt, hover, and button status of the touch component. Thanks to the high signal-to-noise ratio of the active signal and the advanced anti-interference capability of the touch signal detection circuit, the touch device can still achieve sub-millimeter-level positioning accuracy, ultra-low latency writing, and stable hover response even in harsh environments such as high refresh rates of flexible OLEDs and complex dynamic images. This significantly improves the user experience in scenarios such as professional drawing and note-taking, and meets the high-fidelity handwriting input requirements of high-end mobile computing devices.

[0103] The above is a schematic representation of a touch device according to this embodiment. It should be noted that the technical solution of this computing device and the technical solution of the touch signal detection circuit described above belong to the same concept. Details not described in detail in the technical solution of the touch device can be found in the description of the technical solution of the touch signal detection circuit described above.

[0104] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0105] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments in this specification are not limited to the described order of actions, because according to the embodiments in this specification, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in this specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the embodiments in this specification.

[0106] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0107] The preferred embodiments disclosed above are merely illustrative of this specification. The optional embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the embodiments described herein. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the embodiments, thereby enabling those skilled in the art to better understand and utilize this specification. This specification is limited only by the claims and their full scope and equivalents.

Claims

1. A touch signal detection circuit, characterized in that, This includes an interference detection module, a touch detection module, a current replication module, and signal channels corresponding to each sensing unit; The interference detection module is connected to the reference signal channel and is used to perform current detection on the reference signal channel to obtain the interference current. The reference signal channel can be any of the signal channels. The input terminal of the current replication module is connected to the interference detection module, and the output terminal is connected to the touch detection module. It is used to replicate the interference current and inject the replicated current into the touch detection module. The replicated current is in the opposite direction to the interference current. The touch detection module is also connected to other signal channels besides the reference signal channel, and is used to detect touch signals on the connected signal channels.

2. The circuit according to claim 1, characterized in that, It also includes a switching module; The input terminal of the switching module is connected to the signal channel, the first output terminal is connected to the interference detection module, and the second output terminal is connected to the touch detection module. The switching module is used to connect the signal channel to the interference detection module or the touch detection module.

3. The circuit according to claim 2, characterized in that, It also includes a control module; The output of the control module is connected to the switching module, and is used to control the switching module to connect the reference signal channel to the interference detection module when an interference signal is detected.

4. The circuit according to claim 3, characterized in that, The input terminal of the control module is connected to the sensing unit and is also used to determine the reference signal channel from a pre-set candidate signal channel in response to the touch signal of the sensing unit, wherein the sensing unit corresponding to the reference signal channel is different from the sensing unit corresponding to the touch signal.

5. The circuit according to claim 1, characterized in that, The current replication module includes multiple current mirror units connected in parallel, and the touch detection module includes multiple touch detection sub-modules, with different touch detection sub-modules connected to different signal channels; The input terminal of each current mirror unit is connected to the reference signal channel, and the output terminal is connected to any of the touch detection submodules. Different current mirror units are connected to different touch detection submodules.

6. The circuit according to claim 5, characterized in that, The signal channel includes parasitic capacitance. The parasitic capacitances of different signal channels are connected to different current mirror units. The parasitic capacitances of the reference signal channel are connected to a first current mirror unit. The parasitic capacitances of other signal channels besides the reference signal channel are connected to a second current mirror unit. The first current mirror unit is any one of the current mirror units, and the second current mirror unit is any current mirror unit other than the first current mirror unit. The current replication module is used to replicate the interference current based on the parasitic capacitance to obtain the replicated current.

7. A method for detecting touch signals, characterized in that, An application is made in a touch signal detection circuit, the touch signal detection circuit including an interference detection module, a touch detection module, a current replication module, and signal channels corresponding to each sensing unit; the interference detection module is connected to a reference signal channel, the input terminal of the current replication module is connected to the interference detection module, the output terminal is connected to the touch detection module, and the touch detection module is also connected to other signal channels besides the reference signal channel; the method includes: The interference detection module performs current detection on the reference signal channel to obtain the interference current; and sends the interference current to the current replication module, wherein the reference signal channel is any of the signal channels. The current replication module replicates the interference current and injects the replicated current into the touch detection module, wherein the replicated current is in the opposite direction to the interference current; The touch detection module detects touch signals on the connected signal channel based on the replicated current.

8. A touch position positioning method, characterized in that, include: Obtain the touch signal detection result, wherein the touch signal detection result is obtained by the touch signal detection circuit based on the method described in claim 7; Based on the touch signal detection results, the touch position is located.

9. A touch device, characterized in that, It includes a touch panel and a touch signal detection circuit as described in any one of claims 1 to 6.

10. A touch device, characterized in that, It includes a touch component, a touch panel, and a touch signal detection circuit as described in any one of claims 1 to 6.

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