Touch display device and operating method thereof
By introducing a sample-and-hold circuit and an analog-to-digital converter into the touch display device, and adjusting the pulse width and sampling frequency of the sample-and-hold signal, the problems of limited carrier frequency selection and low noise ratio are solved, resulting in a better human-computer interaction effect.
Patent Information
- Application Number
- CN202511058426.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-30
- Publication Date
- 2025-10-31
AI Technical Summary
Existing touch display devices suffer from limited carrier frequency selection and low noise ratio, which restricts communication between active styluses and touch display devices, affecting the human-computer interaction effect.
By introducing sample-and-hold circuitry, analog-to-digital converters, and processing circuitry into touch display devices, the pulse width and sampling frequency of the sample-and-hold signal are adjusted to expand the frequency selectivity of the carrier frequency and suppress the effects of noise.
It improved the noise ratio of the sampled data, expanded the carrier frequency selection of the downlink signal, and realized diverse and accurate human-computer interaction functions.
Smart Images
Figure CN120872183A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a touch display device, and more particularly to a touch display device using an active stylus and its operating method. Background Technology
[0002] Touch display devices can perform touch operations based on downlink signals output by an active stylus, enabling human-computer interaction. Specifically, the active stylus carries various information via different carriers in the downlink signal, such as different touch information from the tip electrode and ring electrode. The touch display device processes the received downlink signal (including sampling) to generate corresponding touch data and executes the touch operation accordingly.
[0003] refer to Figure 1 , Figure 1 This is a schematic diagram of the operation of a current touch display device. Due to transmission interference and sampling frequency limitations, current touch data has a low noise ratio due to phenomena such as downlink jitter and aliasing. Figure 1 As shown, the carrier frequency and noise have multiple peaks, expressed as standard deviation, relative to different carrier frequencies, such as P1, P2, and P3. Thus, the current carrier frequency selection is limited to the frequency bands corresponding to these peaks P1 to P3. Furthermore, the current carrier frequencies must comply with the communication specifications between active styluses and touch display devices, further restricting the choice of carrier frequency. Summary of the Invention
[0004] This invention provides a touch display device suitable for active styluses, which can expand the frequency selection of carrier frequencies and improve the noise ratio of sampled data.
[0005] The touch display device of this invention includes a sample-and-hold circuit, an analog-to-digital converter (ADC), and a processing circuit. The sample-and-hold circuit receives a downlink signal from an active stylus. The ADC is coupled to the sample-and-hold circuit. The ADC samples the downlink signal based on the sample-and-hold signal to generate sampled data. The ADC converts the sampled data into digital data. The processing circuit is coupled to the sample-and-hold circuit and the ADC. The processing circuit performs touch operations on the active stylus based on the digital data. The processing circuit adjusts the sampling frequency of the sample-and-hold signal according to a set value of the carrier frequency of the downlink signal.
[0006] This invention also provides an operation method for a touch display device. The method includes the following steps: receiving a downlink signal from an active stylus via a sample-and-hold circuit; sampling the downlink signal according to the sample-and-hold signal using an analog-to-digital converter to generate sampled data; converting the sampled data into digital data using the analog-to-digital converter; performing a touch operation of the active stylus based on the digital data using a processing circuit; and adjusting the sampling frequency of the sample-and-hold signal according to a set value for the carrier frequency of the downlink signal using the processing circuit.
[0007] Based on the above, the touch display device and its operating method according to embodiments of the present invention adjust the pulse width of the sample-and-hold signal of the analog-to-digital converter according to various carrier frequencies through a processing circuit, thereby modulating the downlink signal to suppress the frequency band affected by noise in the sampled data. In this way, the touch display device can improve the noise ratio of the sampled data and also expand the frequency selection of the carrier frequency of the downlink signal.
[0008] 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. Attached Figure Description
[0009] Figure 1 This is a schematic diagram of the operation of a current touch display device;
[0010] Figure 2 This is a circuit block diagram of a touch display device according to an embodiment of the present invention;
[0011] Figure 3 This is a flowchart illustrating an operation method of a touch display device according to an embodiment of the present invention;
[0012] Figure 4A as well as Figure 4B This is a schematic diagram of the operation of a touch display device according to another embodiment of the present invention;
[0013] Figure 5 Based on the present invention Figure 4A as well as Figure 4B The example illustrates the relationship between the standard deviation of carrier frequency and noise and carrier frequency.
[0014] Explanation of icon numbers
[0015] 200: Touch display device;
[0016] 210: Processing circuit;
[0017] 220: Analog-to-digital converter;
[0018] 230: Sample and hold circuit;
[0019] 300: Active stylus;
[0020] D1, D1(a): Sample data;
[0021] DL: Downlink signal;
[0022] P1~P3: Peak values;
[0023] S310~S330: Steps;
[0024] S / H, S / H(a), S / H(b), S / H(c), S / H(d): Sample and hold signals;
[0025] UL: Uplink signal;
[0026] V1~V2: Voltage values;
[0027] W1, W11~w13: Positive pulse width;
[0028] W2, W21~w23: Negative pulse width. Detailed Implementation
[0029] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same component reference numerals are used in the drawings and description to denote the same or similar parts.
[0030] Figure 2 This is a circuit block diagram of a touch display device according to an embodiment of the present invention. (Reference) Figure 2 The touch display device 200 is compatible with an active stylus 300. The tip electrode and ring electrode in the active stylus 300 transmit the touch information carried by the downlink signal DL at different carrier frequencies. These different carrier frequencies need to be spaced a certain difference to be distinguishable by the touch display device 200. For example, the tip electrode can be selected from... Figure 1 The 160 kHz shown is used as the first carrier frequency. When the difference between the first carrier frequency of the head electrode and the second carrier frequency of the ring electrode falls within the range shown... Figure 1 At the peak value P2 (i.e., 200 kHz), the touch display device 200 will reselect the carrier frequencies of the head electrode and the ring electrode respectively.
[0031] The touch display device 200 can change the high-noise frequency band by modifying the pulse width of the sample-and-hold signal through the modulation sample-and-hold circuit 230, thereby expanding the frequency selection of the carrier frequency of the downlink signal DL. This frequency band is used to perform touch operations by the active stylus 300. In this way, the touch display device 200 and the active stylus 300 can achieve diverse and accurate human-computer interaction functions.
[0032] exist Figure 2 In this embodiment, the touch display device 200 includes a processing circuit 210, an analog-to-digital converter 220, and a sample-and-hold circuit 230. The sample-and-hold circuit 230 is coupled to both the analog-to-digital converter 220 and the processing circuit 210. The analog-to-digital converter 220 is coupled to both the sample-and-hold circuit 230 and the processing circuit 210. The sample-and-hold circuit 230 receives a downlink signal DL from the active stylus 300. The analog-to-digital converter 220 converts the analog signal (e.g., sampled data) provided by the sample-and-hold circuit 230 into digital data to perform touch operations on the active stylus 300.
[0033] The processing circuit 210 may include, for example, a timing controller, a signal converter, a field programmable gate array (FPGA), a central processing unit (CPU), or other programmable general-purpose or special-purpose microprocessor, digital signal processor (DSP), programmable controller, application-specific integrated circuit (ASIC), programmable logic device (PLD), or other similar devices or combinations thereof, which can load and execute computer program-related firmware or software to perform control and various calculation functions.
[0034] Figure 3 This is a flowchart illustrating an operation method of a touch display device according to an embodiment of the present invention. (See reference) Figure 2 as well as Figure 3 The touch display device 200 executes steps S310 to S330 to implement the application of touch operation frequency. The order of these steps S310 to S330 is only an example and is not limited thereto.
[0035] The touch display device 200 sets the sample and hold signal S / H to a plurality of pulse signals with a sampling frequency. The touch display device 200 sends an uplink signal UL to the active stylus 300. The uplink signal UL includes at least one carrier wave to indicate setting information. The setting information includes a set value for the carrier frequency of the downlink signal DL. The set value for the carrier frequency can be one or more frequencies. The downlink signal DL includes a plurality of carrier frequencies. When the noise ratio of the set value of any of the plurality of carrier frequencies is lower than a threshold, the touch display device 200 executes step S310.
[0036] In step S310, when the noise ratio of a set value of one of the carrier frequencies set for the downlink signal DL is lower than a threshold, the processing circuit 210 adjusts the frequency or pulse width of the sample-and-hold signal S / H. That is, the processing circuit 210 adjusts the data sampling and holding period of the downlink signal DL according to the set values of one or more carrier frequencies, thereby changing the sampling frequency of the sample-and-hold signal S / H. In this way, the downlink signal DL can change to a frequency band with a low noise ratio based on the adjusted sample-and-hold signal S / H, thereby improving the noise ratio of the set value of the downlink signal DL carrier frequency to perform subsequent touch operations.
[0037] In step S320, the sample-and-hold circuit 230 receives a downlink signal DL from the active stylus 300. The sample-and-hold circuit 230 transmits the downlink signal DL to the analog-to-digital converter 220. The downlink signal DL may include multiple carriers with different frequencies to indicate various information. The multiple carriers include a first carrier frequency corresponding to the tip electrode of the active stylus 300 and a second carrier frequency corresponding to the ring electrode of the active stylus 300. The information includes touch information corresponding to the tip electrode of the active stylus 300 based on the first carrier frequency and touch information corresponding to the ring electrode of the active stylus 300 based on the second carrier frequency.
[0038] In step S330, the analog-to-digital converter 220 samples the downlink signal DL according to the sample-and-hold signal S / H to generate sampled data. The analog-to-digital converter 220 converts the sampled data into digital data and outputs the digital data to the processing circuit 210.
[0039] In step S340, the processing circuit 210 executes the touch operation of the active stylus 300 according to the digital data. The touch operation includes determining the position of the active stylus 300 on the touch screen of the touch display device 200 and determining the operating state of the active stylus 300, so as to realize the touch function.
[0040] It is worth mentioning that by adjusting the pulse width of the sample-and-hold signal S / H according to multiple carrier frequencies of the downlink signal DL (e.g., extending the pulse high-level time), the sampling frequency of the sample-and-hold signal S / H can be changed. Provided that the minimum number of samples meets system requirements, the frequency band with the low noise ratio of the downlink signal DL can be changed. Thus, the touch display device 200 can use more frequency bands of the downlink signal DL to expand the frequency selection of carrier frequencies.
[0041] Figure 4A as well as Figure 4B This is a schematic diagram illustrating the operation of a touch display device according to another embodiment of the present invention. (See reference) Figure 4A as well as Figure 4B The touch display device samples the downlink signal DL through a sample-and-hold circuit and an analog-to-digital converter to generate corresponding digital data D1(a) or D1. Figure 4A as well as Figure 4B In the diagram, the horizontal axis represents the operation time of the touch display device, and the vertical axis represents the voltage value.
[0042] exist Figure 4A In this embodiment, the touch display device may be operating in an initial stage before the sample-and-hold signal S / H(a) has been adjusted. The sample-and-hold signal S / H(a) may be, for example, a default sample-and-hold signal with a default sampling frequency. The analog-to-digital converter samples the downlink signal DL with the sample-and-hold signal S / H(a), and generates corresponding digital data D1(a). The processing circuit receives the digital data D1(a) and performs touch operation processing accordingly.
[0043] The sample-and-hold signal S / H(a) can be, for example, a series of pulse signals that alternate between voltage values V1 and V2. Voltage value V1 is greater than voltage value V2. The pulse width of voltage value V1 is a positive pulse width W1. The pulse width of voltage value V2 is a negative pulse width W2. The positive pulse width W1 is less than the negative pulse width W2.
[0044] exist Figure 4B In this embodiment, the touch display device may adjust, for example, based on the sample-and-hold signal S / H(a), to illustrate the implementation details of step S310. The touch display device uses processing circuitry (e.g., Figure 2 The processing circuit 210 shown adjusts the pulse width of the sample-and-hold signal S / H(a) to achieve the frequency conversion effect.
[0045] In the first adjustment method, the processing circuit adjusts the pulse width of the sample-and-hold signal S / H(a) by increasing the duty cycle of S / H(a) to generate an adjusted sample-and-hold signal S / H(b). That is, the positive pulse width W11 corresponding to the voltage value V1 of the adjusted sample-and-hold signal S / H(b) is different from (for example, greater than) the positive pulse width W1 of the sample-and-hold signal S / H(a). Similarly, the negative pulse width W21 corresponding to the voltage value V2 of the adjusted sample-and-hold signal S / H(b) is different from (for example, greater than) the negative pulse width W2 of the sample-and-hold signal S / H(a).
[0046] In the second adjustment method, the processing circuit adjusts the pulse width of the sample-and-hold signal S / H(a) by fixing the width of the negative pulse width W2 and adjusting (e.g., increasing) the width of the positive pulse width W1 of the sample-and-hold signal S / H(a), thereby generating an adjusted sample-and-hold signal S / H(c). That is, the positive pulse width W12 corresponding to the voltage value V1 of the adjusted sample-and-hold signal S / H(c) is greater than the positive pulse width W1 of the sample-and-hold signal S / H(a). The negative pulse width W22 corresponding to the voltage value V2 of the adjusted sample-and-hold signal S / H(c) is equal to the negative pulse width W2 of the sample-and-hold signal S / H(a).
[0047] In the third adjustment method, the processing circuit adjusts the pulse width of the sample-and-hold signal S / H(a) by fixing the width of the positive pulse width W1 and adjusting (e.g., increasing) the width of the negative pulse width W2 of the sample-and-hold signal S / H(a), thereby generating an adjusted sample-and-hold signal S / H(d). That is, the positive pulse width W13 corresponding to the voltage value V1 of the adjusted sample-and-hold signal S / H(d) is equal to the positive pulse width W1 of the sample-and-hold signal S / H(a). The negative pulse width W23 corresponding to the voltage value V2 of the adjusted sample-and-hold signal S / H(d) is greater than the negative pulse width W2 of the sample-and-hold signal S / H(a).
[0048] Based on the above adjustment methods, each of the adjusted sample-and-hold signals S / H(b) to S / H(d) has a sufficient data sampling and holding period to meet the minimum number of samples, and at the same time has a reduced sampling frequency.
[0049] Please refer to the above. Figure 5 , Figure 5 Based on the present invention Figure 4A as well as Figure 4B The example illustrates the relationship between the standard deviation of carrier frequency and noise and the carrier frequency. Figure 5 In the diagram, the horizontal axis represents the carrier frequency of the downlink signal DL, and the vertical axis represents the standard deviation of the carrier frequency from the noise level.
[0050] like Figure 5 As shown, the standard deviation of the carrier frequency from the noise has multiple peaks P1 to P2. That is to say, based on the sample-and-hold signal S / H(a), the carrier frequency that the downlink signal DL can use must avoid the carrier frequencies corresponding to these peaks P1 and P2.
[0051] On the other hand, the sample-and-hold signal S / H(b) with adjusted sampling frequency has different peak values P3 for the standard deviation of the carrier frequency and noise. Thus, the carrier frequency that the downlink signal DL can use is not limited by peak values P1 and P2. Therefore, touch display devices can increase the flexibility of the downlink signal DL in carrier frequency selection.
[0052] The sample-and-hold signal S / H(a) may, for example, have a default sampling frequency of 1040 kHz. The sample-and-hold signal S / H(b) may, for example, have a sampling frequency of 666 kHz.
[0053] In summary, the touch display device and its operating method according to embodiments of the present invention can change the sampling frequency of the sample-and-hold signal by adjusting the pulse width of the sample-and-hold signal in the sample-and-hold circuit. Thus, the touch display device can change the frequency band where the sampled data is affected by noise. The touch display device can increase the frequency selection possibilities of the downlink signal carrier frequency.
[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A touch display device, characterized in that, include: Sample and hold circuit, which receives downlink signals from active stylus; An analog-to-digital converter, coupled to the sample-and-hold circuit, samples the downlink signal according to the sample-and-hold signal to generate sampled data, and converts the sampled data into digital data; and The processing circuit is coupled to the sample-and-hold circuit and the analog-to-digital converter, and executes the touch operation of the active stylus based on the digital data. The processing circuit adjusts the sampling frequency of the sample-and-hold signal according to the set value of the carrier frequency of the downlink signal.
2. The touch display device according to claim 1, characterized in that, The processing circuit adjusts the data sampling and holding period of the downlink signal according to the set value of the carrier frequency of the downlink signal, so as to change the sampling frequency of the sample-and-hold signal.
3. The touch display device according to claim 2, characterized in that, The sample-and-hold circuit adjusts the sampling frequency of the sample-and-hold signal by adjusting the width of the positive pulse width of the sample-and-hold signal.
4. The touch display device according to claim 2, characterized in that, The processing circuit adjusts the sampling frequency of the sample-and-hold signal by adjusting the width of the negative pulse width of the sample-and-hold signal.
5. The touch display device according to claim 1, characterized in that, The downlink signal includes multiple carrier frequencies.
6. The touch display device according to claim 5, characterized in that, When the noise ratio of any of the set values of the plurality of carrier frequencies is lower than a threshold, the sample-and-hold circuit adjusts the sampling frequency of the sample-and-hold signal.
7. The touch display device according to claim 5, characterized in that, The plurality of carrier frequencies include a first carrier frequency corresponding to the tip electrode of the active stylus and a second carrier frequency corresponding to the ring electrode of the active stylus.
8. The touch display device according to claim 1, characterized in that, The sample-and-hold circuit sends an uplink signal to the active stylus, wherein the uplink signal includes at least one carrier wave to indicate setting information, and the setting information includes the set value of the carrier frequency of the downlink signal.
9. A method for operating a touch display device, characterized in that, include: The downlink signal from the active stylus is received through the sample-and-hold circuit. The downlink signal is sampled using an analog-to-digital converter based on the sample-and-hold signal to generate sampled data, and the sampled data is converted into digital data. The active stylus is used for touch operations based on the digital data via a processing circuit; and The processing circuit adjusts the sampling frequency of the sample-and-hold signal according to the set value of the carrier frequency of the downlink signal.
10. The operating method according to claim 9, characterized in that, The step of adjusting the sampling frequency of the sample-and-hold signal by the processing circuit according to the set value of the carrier frequency of the downlink signal includes: The processing circuit adjusts the data sampling and holding period of the downlink signal according to the set value of the carrier frequency of the downlink signal, thereby changing the sampling frequency of the sample-and-hold signal.
11. The operating method according to claim 10, characterized in that, The step of adjusting the sampling frequency of the sample-and-hold signal by the processing circuit according to the set value of the carrier frequency of the downlink signal includes: The processing circuit adjusts the width of the positive pulse of the sample-and-hold signal to adjust the sampling frequency of the sample-and-hold signal.
12. The operating method according to claim 10, characterized in that, The step of adjusting the sampling frequency of the sample-and-hold signal by the processing circuit according to the set value of the carrier frequency of the downlink signal includes: The processing circuit adjusts the width of the negative pulse of the sample-and-hold signal to adjust the sampling frequency of the sample-and-hold signal.
13. The operating method according to claim 9, characterized in that, The downlink signal includes multiple carrier frequencies.
14. The operating method according to claim 13, characterized in that, When the noise ratio of any of the set values of the plurality of carrier frequencies is lower than a threshold, the sample-and-hold circuit adjusts the sampling frequency of the sample-and-hold signal.
15. The operating method according to claim 13, characterized in that, The plurality of carrier frequencies include a first carrier frequency corresponding to the tip electrode of the active stylus and a second carrier frequency corresponding to the ring electrode of the active stylus.
16. The operating method according to claim 9, characterized in that, Also includes: The sample-and-hold circuit sends an uplink signal to the active stylus, wherein the uplink signal includes at least one carrier wave to indicate setting information, and the setting information includes the set value of the carrier frequency of the downlink signal.