Touch display devices and sensing methods with active pens

Abstract

This invention proposes a touch display device for use with an active pen. During touch sensing, the touch position is detected. During active pen sensing, an uplink signal is transmitted and a downlink signal is detected. When a downlink signal is detected, it is determined whether the distance between the active pen position and the touch position is less than or equal to a first preset distance; if so, the device does not enter active pen mode.

Description

[Technical Field]

[0001] This invention relates to a touch display device that can avoid misinterpreting downstream signals. [Background Technology]

[0002] Recently, active pens have become widely used as human-interface devices (HIDs) for smartphones and tablets. Active pens include passive active pens and active pens. In typical active pen operation, the touchscreen sends uplink signals to the active pen, while the active pen sends downlink signals to the touchscreen. However, sometimes the device is connected to noisy sources (such as a charger). If the noise is mistaken for a downlink signal, operational errors can occur. [Summary of the Invention]

[0003] This invention provides a touch display device for use with an active pen, comprising a touch display panel and circuitry. The touch display panel includes multiple sensing electrodes, and the circuitry is electrically connected to the sensing electrodes via multiple sensing lines. During touch sensing, the circuitry detects the touch position based on a first signal on the sensing lines. During active pen sensing, the circuitry transmits an uplink signal to the sensing electrodes and detects a downlink signal from the active pen and the active pen position based on multiple second signals on the sensing lines. When a downlink signal is detected, the circuitry determines whether the distance between the active pen position and the touch position is less than or equal to a first preset distance. If the distance between the active pen position and the touch position is greater than the first preset distance, the circuitry enters an active pen mode, in which the touch position is not detected. If the distance between the active pen position and the touch position is less than or equal to the first preset distance, the circuitry does not enter active pen mode.

[0004] In some embodiments, the circuit includes a demodulator, an analog-to-digital converter, and a computing circuit. The demodulator is electrically connected to a sensing line to output multiple demodulated signals based on a second signal. The analog-to-digital converter is electrically connected to the demodulator and outputs active pen values ​​corresponding to the sensing electrodes based on the demodulated signals. The computing circuit is electrically connected to the analog-to-digital converter and is used to determine the active pen position based on the active pen values ​​and to determine whether the active pen values ​​are greater than a first threshold. If the active pen values ​​are greater than the first threshold, the computing circuit determines that a downstream signal has been detected.

[0005] In some embodiments, the computing circuit calculates the weighted sum of the positions of the sensing electrodes as the active pen position, wherein the weight of each sensing electrode is proportional to the corresponding active pen value.

[0006] In some embodiments, if the distance between the active pen position and the touch position is less than or equal to a first preset distance, the circuit determines whether the active pen value is greater than a second threshold value, wherein the second threshold value is greater than the first threshold value. If the active pen value is less than or equal to the second threshold value, the circuit ignores the downstream signal and does not enter the active pen mode.

[0007] In some embodiments, if the active pen value is greater than a second threshold value, the circuit enters active pen mode.

[0008] In some embodiments, if the active pen position is the same as the touch position, the circuit does not enter active pen mode.

[0009] In some embodiments, if the circuit does not detect a downstream signal within a preset time, the circuit terminates the active pen mode and re-detects the touch position.

[0010] In some embodiments, the touch display device is connected to a charger.

[0011] From another perspective, embodiments of the present invention propose a sensing method for an active pen, applicable to a touch display panel. The touch display panel includes multiple sensing electrodes, and multiple sensing lines are respectively connected to the sensing electrodes. The sensing method includes: during touch sensing, detecting a touch position based on a first signal on the sensing lines; during active pen sensing, transmitting an uplink signal to the sensing electrodes, and detecting a downlink signal from the active pen and the active pen position based on multiple second signals on the sensing lines; when the downlink signal is detected, determining whether the distance between the active pen position and the touch position is less than or equal to a first preset distance; if the distance between the active pen position and the touch position is greater than or equal to the first preset distance, entering an active pen mode, in which the touch position is not detected; and if the distance between the active pen position and the touch position is less than or equal to the first preset distance, not entering the active pen mode.

[0012] In some embodiments, the sensing method further includes: outputting a plurality of demodulated signals by a demodulator based on a second signal; outputting active pen values ​​corresponding to sensing electrodes by an analog-to-digital converter based on the demodulated signals; determining the active pen position based on the active pen values ​​and determining whether the active pen values ​​are greater than a first threshold value; and determining that a downstream signal is detected if the active pen values ​​are greater than the first threshold value.

[0013] In some embodiments, the sensing method further includes: calculating the weights of the positions of the sensing electrodes as the active pen positions, wherein the weight of each sensing electrode is proportional to the corresponding active pen value.

[0014] In some embodiments, the sensing method further includes: if the distance between the active pen position and the touch position is less than or equal to a first preset distance, determining whether the active pen value is greater than a second threshold value, wherein the second threshold value is greater than the first threshold value; and if the active pen value is less than or equal to the second threshold value, ignoring the downlink signal and not entering the active pen mode.

[0015] In some embodiments, the sensing method further includes: if the active pen value is greater than a second threshold, entering active pen mode.

[0016] In some embodiments, the sensing method further includes: if the active pen position is the same as the touch position, not entering the active pen mode.

[0017] In some embodiments, the sensing method further includes: if no downstream signal is detected within a preset time, ending the active pen mode and re-detecting the touch position.

[0018] In the above-described apparatus and method, noise can be avoided from being mistaken for a downstream signal. [Attached Image Description]

[0019] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings.

[0020] Figure 1A and Figure 1B This is a schematic diagram illustrating a usage scenario of a sensing system according to an embodiment.

[0021] Figure 2 This is a schematic diagram of a touch display device 120 according to one embodiment.

[0022] Figure 3 This is a circuit diagram of a sensing circuit 210 according to one embodiment.

[0023] Figure 4 This is a flowchart illustrating a specific embodiment for determining whether to enter active pen mode.

[0024] Figure 5 This is a flowchart illustrating a specific embodiment for determining whether to enter active pen mode.

[0025] Figure 6 This is a schematic diagram illustrating the switching between general mode and active pen mode according to an embodiment.

[0026] [Symbol Explanation]

[0027] 100: Sensing System

[0028] 110: Active pen

[0029] 120: Touch display device

[0030] 130: Hand

[0031] DL: Downlink signal

[0032] UL: Uplink signal

[0033] 140: Charger

[0034] 210: Sensing Circuit

[0035] 220: Gate driver

[0036] 230: Source Driver

[0037] GL: Gate line

[0038] DL: Data cable

[0039] SL: Sensing line

[0040] SE: Sensing electrode

[0041] 201: Touch display panel

[0042] P: Pixel structure

[0043] Cf, Cs: Capacitance

[0044] 310: Demodulator

[0045] 311: Demodulated signal

[0046] 320: Analog-to-Digital Converter

[0047] 321: Digital signal

[0048] 330: Calculation Circuit

[0049] 340: Noise

[0050] 401-405, 501-503: Steps

[0051] 610: Display period

[0052] 620: During touch sensing

[0053] 630: Active pen sensing period

Detailed Implementation Methods

[0054] The terms "first," "second," etc., used in this article do not specifically refer to order or sequence; they are merely used to distinguish components or operations described using the same technical terms.

[0055] Figure 1A and Figure 1B This is a schematic diagram illustrating a usage scenario of a sensing system according to an embodiment. Please refer to... Figure 1AThe sensing system 100 includes an active pen 110 and a touch display device 120. The user holds the active pen 110 with their hand 130 and writes or draws on the touch display device 120. The touch display device 120 has display and touch sensing functions, used to perform corresponding operations in response to the movement trajectory of the active pen 110. The touch display device 120 sends an uplink signal UL to the active pen 110, and the active pen 110 sends a downlink signal DL to the touch display device 120. At this time, the touch display device 120 enters active pen mode. In this mode, the hand 130 is not detected because the user usually places their hand 130 on the touch display panel 201 while using the active pen 110, and the hand 130 at this time does not represent the user's desired operation. For example, the hand 130 may touch an icon, but the user does not intend to activate the target function of that icon.

[0056] exist Figure 1B In this usage scenario, the user is not holding the active stylus but only sliding their finger across the touch display device 120. Simultaneously, the touch display device 120 is connected to the charger 140 and charging. At this time, noise generated by the charger 140 might be mistaken for a downlink signal DL. If the touch display device 120 enters active stylus mode, it may fail to detect the hand 130. To avoid misjudgment, this embodiment checks whether the distance between the active stylus position and the touch position is less than a preset distance; if so, the corresponding downlink signal DL may be ignored.

[0057] Figure 2 This is a schematic diagram of a touch display device 120 according to one embodiment. Please refer to... Figure 2The touch display device 120 includes a touch and display driver integration (TDDI) circuit and a touch display panel 201. The TDDI circuit includes a sensing circuit 210, a gate driver 220, and a source driver 230 in the non-display area. For simplicity, the source driver 230 is shown above the sensing circuit 210, but in some embodiments, the source driver 230 and the sensing circuit 210 may be integrated into the same circuit. The touch display panel 201 includes multiple sensing electrodes SE, pixel structures P, sensing lines SL, gate lines GL, and data lines DL. The sensing electrodes SE are electrically insulated from each other and electrically connected to the sensing circuit 210 via sensing lines SL. Each sensing electrode SE corresponds to multiple pixel structures P and serves as a common electrode for the corresponding pixel structures P. Each pixel structure P includes a thin-film transistor (not shown) and a pixel electrode (not shown). Each gate line GL is connected to the gate driver 220 and the gate of the thin-film transistor in the corresponding pixel structure P. Each data line DL is connected to the source driver 230 and the source of the thin-film transistor in the corresponding pixel structure P. The drain of the thin-film transistor is connected to the pixel electrode. For simplicity, Figure 2 Not all circuits (such as timing controllers) are shown in the diagram, so the above-mentioned integrated touch and display driver circuit may also include other components.

[0058] During display, gate driver 220 turns on the corresponding thin-film transistor via gate line GL, while source driver 230 transmits the corresponding pixel data to the corresponding pixel electrode via data line DL. Sensing circuit 210 applies a common voltage to sensing electrode SE via sensing line SL. The voltage difference between the pixel electrode and sensing electrode SE is used to rotate liquid crystal molecules (not shown) to determine the brightness of a pixel. In other embodiments, touch display panel 201 may also be an organic light-emitting diode panel or other suitable panel.

[0059] During touch sensing, a self-capacitance sensing method is used to determine whether each sensing electrode SE is touched. Specifically, a capacitor Cs is formed on each sensing electrode SE (for simplicity, ...). Figure 2Only one capacitor Cs is illustrated. When a finger touches a sensing electrode SE, another capacitor Cf is formed between the finger and the sensing electrode SE, causing a change in the total capacitance on the touched sensing electrode SE. The sensing circuit 210 can transmit a touch sensing signal to the sensing electrode SE via the sensing line SL. This touch sensing signal can have any suitable waveform such as a square wave, triangle wave, or sine wave, and the present invention is not limited thereto. The amount of charge accumulated on the sensing electrode SE reflects its capacitance value and generates a corresponding signal on the sensing line SL. The sensing circuit 210 can determine which sensing electrodes SE are touched based on these signals, thereby calculating a touch position. In other embodiments, the touch display panel 201 can also adopt a mutual capacitance touch sensing method, and the present invention is not limited thereto.

[0060] Figure 3 This is a circuit diagram of a sensing circuit 210 according to one embodiment. Please refer to... Figure 3 The sensing circuit 210 includes at least a demodulator 310, an analog-to-digital converter 320, and a computing circuit 330. The demodulator 310 is electrically connected to the sensing electrode SE via a sensing line SL, the analog-to-digital converter 320 is electrically connected to the demodulator 310, and the computing circuit 330 is electrically connected to the analog-to-digital converter 320. For simplicity, Figure 3 Not all components of the sensing circuit 210 are shown in the figure. For example, a multiplexer, integrator, etc. can also be set between the demodulator 310 and the sensing electrode SE.

[0061] During active pen sensing, sensing circuit 210 transmits an uplink signal UL to sensing electrode SE, which then transmits it to active pen 110. Upon receiving the uplink signal UL, active pen 110 transmits a downlink signal DL to sensing electrode SE. This downlink signal DL is modulated onto a carrier at a specific frequency (e.g., 285 kHz), therefore demodulator 310 must first demodulate the signal on sensing line SL to output demodulated signal 311. Analog-to-digital converter outputs digital signals 321 based on demodulated signal 311. These digital signals 321 represent an active pen value corresponding to sensing electrode SE; the larger the active pen value, the stronger the downlink signal DL. Calculation circuit 330 also determines whether these active pen values ​​are greater than a first threshold. If so, calculation circuit 330 determines that a downlink signal has been detected; if none of the active pen values ​​are greater than the first threshold, it indicates that no downlink signal has been detected. The calculation circuit 330 can also determine an active pen position based on these active pen values, for example, by calculating the weighted sum of the positions of the sensing electrodes SE, where the weights are proportional to the active pen values. This invention does not limit how the active pen position is calculated.

[0062] Noise 340 generated by charger 140 may also be transmitted to sensing electrode SE. If the frequency of this noise is the same as or similar to the downlink signal DL, the corresponding active pen value may be greater than the first threshold, resulting in a false judgment. In this embodiment, if the downlink signal is detected, the calculation circuit 330 will also determine whether the distance between the active pen position and the aforementioned touch position is less than or equal to a preset distance. If the distance between the active pen position and the aforementioned touch position is greater than the preset distance, the sensing circuit 210 will enter an active pen mode, in which the touch position will not be detected. In some embodiments, "not detecting the touch position" means that the aforementioned touch sensing signal will not be transmitted, but in some embodiments it may also mean that the touch sensing signal is transmitted, but after calculating the touch position, no corresponding operation will be performed on the touch display panel 201. On the other hand, if the distance between the active pen position and the touch position is less than the preset distance, it means that the active pen position may be generated by noise, and therefore the active pen mode may not be entered. There are two mechanisms to determine whether to enter the active pen mode, which will be explained below. Figure 4 and Figure 5 Detailed explanation.

[0063] Figure 4 This is a flowchart illustrating a specific embodiment for determining whether to enter active pen mode. Figure 4 In this embodiment, in step 401, it is first determined whether a downlink signal is detected (i.e., whether an active pen value is greater than a first threshold). If not, the process remains in normal mode in step 402. If a downlink signal is detected, in step 403, it is further determined whether the distance between the active pen position and the touch position is less than or equal to a preset distance. If not, the process enters active pen mode in step 404; otherwise, in step 405, the downlink signal is ignored and the process remains in normal mode (without entering active pen mode). In some embodiments, the preset distance can also be 0, meaning that the process remains in normal mode when the active pen position and the touch position are the same.

[0064] Figure 5 This is a flowchart illustrating a specific embodiment for determining whether to enter active pen mode. Figure 5 Steps 401 to 404 have been described above and will not be repeated here. If the result of step 403 is yes, in step 501, it is further determined whether the active pen value is greater than a second threshold value, which is greater than the first threshold value mentioned above. If the result of step 501 is no, then in step 502, the downstream signal is ignored and the system remains in normal mode. If the result of step 501 is yes, then in step 503, the system enters active pen mode. In other words, in Figure 5In some embodiments, a threshold value for the active pen value is increased to reduce the probability of misjudgment. In some embodiments, if the active pen position is the same as the touch position, the normal mode will still be maintained regardless of whether the active pen value is greater than the second threshold value.

[0065] Figure 6 This is a schematic diagram illustrating the switching between general mode and active pen mode according to an embodiment. Please refer to it. Figure 6 In normal mode, the display period 610, touch sensing period 620, and active pen sensing period 630 are executed repeatedly. However, in active pen mode, only the display period 610 and active pen sensing period 630 are executed alternately. If no downlink signal is detected within a preset time (e.g., the time of several frames), the active pen mode will end and the system will return to normal mode to re-detect the touch position.

[0066] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A touch display device for use with an active pen, comprising: The touch display panel includes multiple sensing electrodes; as well as The circuit is electrically connected to the multiple sensing electrodes via multiple sensing lines. During touch sensing, the circuit detects the touch position based on a first signal from the plurality of sensing lines. During active pen sensing, the circuit transmits an uplink signal to the plurality of sensing electrodes and detects a downlink signal from the active pen and the active pen position based on a plurality of second signals on the plurality of sensing lines. When the downstream signal is detected, the circuit determines whether the distance between the active pen position and the touch position is less than or equal to a first preset distance. If the distance between the active pen position and the touch position is greater than the first preset distance, the circuit enters active pen mode, in which the touch position is not detected. If the distance between the active pen position and the touch position is less than or equal to the first preset distance, the circuit will not enter the active pen mode.

2. The touch display device according to claim 1, wherein the circuit comprises: A demodulator, electrically connected to the plurality of sensing lines, outputs a plurality of demodulated signals according to the plurality of second signals; An analog-to-digital converter is electrically connected to the demodulator and outputs the number of active values ​​corresponding to each of the plurality of sensing electrodes based on the plurality of demodulated signals. as well as A computing circuit, electrically connected to the analog-to-digital converter, is used to determine the position of the active pen based on the plurality of active pen values, and to determine whether the plurality of active pen values ​​are greater than a first threshold value. If one of the plurality of active pen values ​​is greater than the first threshold value, the calculation circuit determines that the downstream signal has been detected.

3. The touch display device according to claim 2, wherein the computing circuit calculates the weighted sum of the positions of the plurality of sensing electrodes as the active pen position, wherein the weight of each of the plurality of sensing electrodes is proportional to the corresponding active pen value.

4. The touch display device according to claim 2, wherein if the distance between the active pen position and the touch position is less than or equal to the first preset distance, the circuit determines whether the values ​​of the plurality of active pens are greater than a second threshold value, wherein the second threshold value is greater than the first threshold value. If the values ​​of the plurality of active pens are less than or equal to the second threshold, the circuit ignores the downstream signal and does not enter the active pen mode.

5. The touch display device according to claim 4, wherein if one of the plurality of active pen values ​​is greater than the second threshold value, the circuit enters the active pen mode.

6. The touch display device according to claim 4, wherein if the active pen position is the same as the touch position, the circuit does not enter the active pen mode.

7. The touch display device according to claim 1, wherein if the circuit does not detect the downstream signal within a preset time, the circuit terminates the active pen mode and re-detects the touch position.

8. The touch display device according to claim 1, wherein the touch display device is connected to a charger.

9. A sensing method for an active pen, applicable to a touch display panel, the touch display panel including a plurality of sensing electrodes, and a plurality of sensing lines respectively connected to the plurality of sensing electrodes, the sensing method comprising: During touch sensing, the touch position is detected based on a first signal from the plurality of sensors that are online; During active pen sensing, an uplink signal is transmitted to the plurality of sensing electrodes, and a downlink signal from the active pen and the active pen position are detected based on a plurality of second signals on the plurality of sensing lines. When the downstream signal is detected, it is determined whether the distance between the active pen position and the touch position is less than or equal to a first preset distance; If the distance between the active pen position and the touch position is greater than or equal to the first preset distance, the active pen mode is entered, and the touch position is not detected in the active pen mode. as well as If the distance between the active pen position and the touch position is less than or equal to the first preset distance, the active pen mode will not be entered.

10. The sensing method according to claim 9, further comprising: The demodulator outputs multiple demodulated signals based on the multiple second signals; The analog-to-digital converter outputs active pen values ​​corresponding to each of the plurality of sensing electrodes based on the plurality of demodulated signals; The position of the active pen is determined based on the multiple active pen values, and it is determined whether the multiple active pen values ​​are greater than a first threshold value. as well as If one of the plurality of active pen values ​​is greater than the first threshold, it is determined that the downstream signal has been detected.

11. The sensing method according to claim 10, further comprising: The weighted sum of the positions of the plurality of sensing electrodes is calculated as the active pen position, wherein the weight of each of the plurality of sensing electrodes is proportional to the corresponding active pen value.

12. The sensing method according to claim 10, further comprising: If the distance between the active pen position and the touch position is less than or equal to the first preset distance, determine whether the multiple active pen values ​​are greater than a second threshold value, wherein the second threshold value is greater than the first threshold value; as well as If the values ​​of the multiple active pen strokes are less than or equal to the second threshold, the downstream signal is ignored and the active pen mode is not entered.

13. The sensing method according to claim 12, further comprising: If one of the multiple active pen values ​​is greater than the second threshold value, the active pen mode is entered.

14. The sensing method according to claim 12, further comprising: If the active pen position is the same as the touch position, the active pen mode will not be entered.

15. The sensing method according to claim 9, further comprising: If the downstream signal is not detected within a preset time, the active pen mode is terminated and the touch position is re-detected.

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