Touch display device and operating method thereof

Abstract

The present invention provides a touch display device and an operating method thereof. The touch display device includes a signal receiver, an analog-to-digital converter, a signal transmitter, and a processor. The signal receiver receives a downlink signal from an active stylus. The downlink signal includes an analog touch signal. The analog-to-digital converter converts the analog touch signal into sampled data. When the touch display device is in a low-frequency operating mode, the processor reduces the carrier frequency of the downlink signal provided by the active stylus via the signal transmitter and an uplink signal. The processor reduces the sampling frequency of the analog-to-digital converter and performs touch sensing based on the sampled data.

Description

Technical Field

[0001] This invention relates to a touch display technology and a stylus application technology, and more particularly to a touch display device and its operation method. Background Technology

[0002] Integrating display panels and touch panels into touch display devices is a common application. On the other hand, the touch display device communicates with a supported active stylus and obtains touch signals from the stylus's downlink to determine the stylus's touch position on the touch display device. However, when an active stylus is enabled, both the touch display device and the active stylus consume significant power due to constant communication. Summary of the Invention

[0003] This invention relates to a touch display device and its operating method, which reduces the power consumption of the touch display device and active stylus by adjusting the signal carrier frequency and the sampling frequency of the analog-to-digital converter, thereby saving power.

[0004] According to an embodiment of the present invention, a touch display device includes a signal receiver, an analog-to-digital converter (ADC), a signal transmitter, and a processor. The signal receiver receives a downlink signal from an active stylus, wherein the downlink signal includes an analog touch signal. An analog-to-digital converter (ADC) is coupled to the signal receiver. The ADC converts the analog touch signal into sampled data. The signal transmitter sends an uplink signal to the active stylus. The carrier frequency of the downlink signal provided by the active stylus is adjusted based on the uplink signal. The processor is coupled to the ADC and the signal transmitter. In a low-frequency operating mode of the touch display device, the processor reduces the carrier frequency of the downlink signal provided by the active stylus via the signal transmitter and the uplink signal. The processor reduces the sampling frequency of the ADC and performs touch sensing based on the sampled data.

[0005] According to an embodiment of the present invention, an operation method of a touch display device includes the following steps: obtaining a downlink signal from the active stylus, wherein the downlink signal includes an analog touch signal; converting the analog touch signal into sampled data using an analog-to-digital converter, and performing touch sensing based on the sampled data; in a low-frequency operating mode of the touch display device, reducing the carrier frequency of the downlink signal provided by the active stylus via an uplink signal; and reducing the sampling frequency of the analog-to-digital converter, and performing touch sensing based on the sampled data.

[0006] Based on the above, the touch display device, touch display system, and operating method described in this embodiment of the invention, when the touch display device switches from a high-frequency operating mode to a low-frequency operating mode, the processor in the touch display device first reduces the carrier frequency of the downlink signal provided by the active stylus via the uplink signal, thereby reducing the power consumption of the active stylus. On the other hand, the processor also dynamically adjusts the sampling frequency of the ADC and determines whether the signal-to-noise ratio (SNR) in the sampled data provided by the ADC is suitable or higher than that required by the touch display system, thereby selectively reducing the sampling frequency of the ADC to save power consumption of the ADC and subsequent digital circuits, thus making the touch display device more power-efficient overall. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a touch display system according to an embodiment of the present invention;

[0008] Figure 2A and Figure 2B It is a waveform diagram of each signal in the touch display system;

[0009] Figure 3 This is a flowchart of an operation method of a touch display device according to an embodiment of the present invention. Detailed Implementation

[0010] 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 element references are used in the drawings and description to denote the same or similar parts.

[0011] Figure 1 This is a schematic diagram of a touch display system according to an embodiment of the present invention. The touch display system includes a touch display device 100 and an active stylus 105. The touch display device 100 mainly includes a signal receiver 110 (e.g., an analog front-end circuit), an analog-to-digital converter (ADC) 120, a processor 130, and a signal transmitter 140. The active stylus 105 includes a receiving circuit 106 and a transmitting circuit 107.

[0012] The receiving circuit 106 can obtain the uplink signal in the uplink 104 from the signal transmitter 140 of the touch display device 100. When the touch display device 100 is first started, the processor 130 can send an uplink signal through the signal transmitter 140 to set the carrier frequency of the downlink signal of the active stylus 105 to a first carrier frequency value (e.g., 400kHz) as the default carrier frequency of the downlink signal. Alternatively, the transmission circuit 107 in the active stylus 105 already has the default carrier frequency of the downlink signal in the downlink 102 when it is started. In this embodiment, the communication protocol of the active stylus 105 is usually the highest carrier frequency in the downlink signal as the default carrier frequency (here assumed to be 400kHz).

[0013] The signal receiver 110 of the touch display device 100 receives downlink signals from the active stylus 105. These downlink signals include analog touch signals. An analog-to-digital converter (ADC) 120 is coupled to the signal receiver 110. The ADC 120 converts the analog touch signals into sampled data.

[0014] Signal transmitter 140 is controlled by processor 130. Signal transmitter 140 sends uplink signals to active stylus 105. The carrier frequency of the downlink signal provided by active stylus 105 can be adjusted based on the uplink signal.

[0015] Processor 130 is coupled to ADC 120 and signal transmitter 140. Processor 130 includes touch signal processor 132, signal-to-noise ratio adjuster 134, and timing controller 136. Touch signal processor 132 is coupled to ADC 120. Touch signal processor 132 receives sampled data provided by ADC 120 and performs touch sensing. In this embodiment, "touch sensing" refers to determining the position of active stylus 105 on the touch screen of touch display device 100 by using touch signals in the sampled data.

[0016] A signal-to-noise ratio (SNR) adjuster 134 is coupled to a touch signal processor 132. The SNR adjuster 134 calculates the SNR of the sampled data based on the sampled data and compares the SNR with an initial SNR range to generate a comparison result. A timing controller 136 is coupled to the SNR adjuster 134. Based on the aforementioned comparison result, the timing controller 136 provides an uplink carrier frequency adjustment signal to the signal transmitter 140 and adjusts the sampling frequency of the ADC 120. Figure 1 The operation of each component in the touch display system can be referred to the description in other embodiments.

[0017] Figure 2A and Figure 2B These are waveform diagrams of various signals in the touch display system. Please also refer to... Figure 1 and Figure 2AIn part (a), in the high-frequency operation mode of the touch display device 100, the processor 130 can send an uplink signal through the signal transmitter 140 to set the carrier frequency of the downlink signal of the active stylus 105 to a first carrier frequency value (e.g., 400kHz), and set the sampling frequency of the ADC 120 to the first sampling frequency value, that is, Figure 2A The sampling frequency of part (a) is 1.6MHz. Specifically, assuming the carrier frequency is 400kHz and the number of sampling points sampled by ADC 120 in unit time period TP1 is greater than or equal to 4 (e.g., there are 4 enabled sampling pulses in time period SH1), the signal-to-noise ratio (SNR) requirement of the overall touch display system for touch sensing can be met. If this SNR is set as the initial SNR, then the sampling frequency of ADC 120 needs to be set to greater than or equal to 1.6MHz.

[0018] In this embodiment of the invention, when the processor 130 sends an uplink signal through the signal transmitter 140 to reduce the carrier frequency of the downlink signal of the active stylus 105, the sampling frequency or sampling data processing of the ADC 120 is dynamically adjusted. In addition to saving power consumption of the touch display system, it is also necessary to consider whether the signal-to-noise ratio of the sampling data sampled by the ADC 120 meets the SNR requirements of the overall touch display system.

[0019] See also Figure 1 and Figure 2A In part (b), when the touch display device 100 transitions from a high-frequency operating mode to a low-frequency operating mode, the processor 130 sends an uplink signal via the signal transmitter 140 to adjust the carrier frequency of the downlink signal of the active stylus 105 from a first carrier frequency value (e.g., 400 kHz) to a second carrier frequency value (e.g., 200 kHz). In this embodiment, the first carrier frequency value (400 kHz) is higher than the second carrier frequency value (200 kHz). After adjusting the carrier frequency of the downlink signal, the processor 130 obtains sampled data based on the ADC 120.

[0020] The processor 130 can dynamically reduce the sampling frequency of the ADC 120. For example, when the carrier frequency of the downlink signal of the active stylus 105 is set to a second carrier frequency value (200kHz), if the sampling frequency of the ADC 120 remains unchanged, also at 1.6MHz as in the first carrier frequency value (e.g., 400kHz), the number of sampling points sampled per unit time period TP2 will increase to 8. However, when the processor 130 dynamically reduces the sampling frequency of the ADC 120, the number of sampling points sampled per unit time period TP2 is greater than or equal to 4 (e.g., 6 sampling points), which allows the signal-to-noise ratio of the sampled data to meet the SNR requirements of the overall touch display system. In this embodiment, the processor 130 can set the sampling frequency of the sampled signal in the ADC 120 to a second sampling frequency value (e.g., 800kHz). The number of sampling points sampled per unit time period TP2 is still equal to 4. Time periods SH1 and SH2 also have 4 enabled sampling pulses, which can also make the signal-to-noise ratio of the sampled data meet the SNR requirements of the overall touch display system. In this way, while the SNR after reducing the sampling frequency of the ADC 120 still meets the SNR requirements of the overall touch display system, the power consumption of the ADC 120 can be reduced, and the power consumption of the back-end digital circuits can also be reduced accordingly. That is to say, the processor 130 in this embodiment dynamically reduces the sampling frequency of the ADC 120 according to the signal-to-noise ratio of the sampled data provided by the ADC 120, and performs touch sensing based on this sampled data.

[0021] Figure 2A Part (b) is achieved by reducing the frequency of the sampling signal in the ADC 120. Another embodiment... Figure 2B This reduces the number of sampling data processing operations. For example, processor 130 performs sampling data processing only once between two sampling points, as shown by arrow 205. When the carrier frequency of the downlink signal in the active stylus 105 is set to the second carrier frequency value (200kHz) and the sampling frequency sampled in the unit time period TP3 remains unchanged, with 8 sampling points, processor 130 can be adjusted to perform sampling data processing 4 times.

[0022] Figure 3 This is a flowchart illustrating the operation method of a touch display device 100 according to an embodiment of the present invention. Please also refer to... Figure 1 and Figure 3 In step S302, this operation method begins. In step S305, Figure 1The processor 130 determines the initial downlink signal transmission carrier frequency (e.g., first carrier frequency value / 400kHz) and the sampling frequency of the ADC 120 (e.g., first sampling frequency value / 1.6MHz) to obtain sampled data and perform touch sensing. In step S310, the processor 130 determines whether to enter a low-frequency operating mode. The low-frequency operating mode can be set by the user through the touch display device 100, or the touch display device 100 can automatically enter it after running for a preset period of time, or it can be entered by other situations that require frequency reduction. By applying this embodiment, it is possible to determine how to make the touch display device 100 switch from a high-frequency operating mode to a low-frequency operating mode according to its needs.

[0023] In step S320, the processor 130 reduces the carrier frequency of the downlink signal of the active stylus 105 via the uplink signal. For example, it adjusts the carrier frequency from a first carrier frequency value (e.g., 400 kHz) to a second carrier frequency value (e.g., 200 kHz).

[0024] In steps S330 to S360, the processor 130 determines whether to reduce the sampling frequency of the ADC 120 based on the signal-to-noise ratio of the sampled data, and performs touch sensing based on the sampled data.

[0025] In step S330, ADC 120 samples the touch signal in the downlink signal to obtain sampled data, and processor 130 obtains the signal-to-noise ratio of the sampled data.

[0026] In step S340, the processor 130 determines whether the signal-to-noise ratio (SNR) of the sampled data is higher than the SNR of the initial sampled data. This initial SNR can be a single initial SNR value or an initial SNR range with upper and lower limits.

[0027] When the signal-to-noise ratio (SNR) of the sampled data is higher than the SNR range of the initial sampled data, step S340 is enabled, indicating that the SNR of the sampled data is higher than that required for using the touch display system. Therefore, the process proceeds from step S340 to step S350. In this embodiment, the sampling frequency of the ADC 120 is reduced, for example, from the first sampling frequency value (1.6MHz) to the second sampling frequency value (800kHz). After reducing the sampling frequency of the ADC 120, the process returns from step S350 to step S330.

[0028] When the signal-to-noise ratio of the sampled data is within the initial signal-to-noise ratio range, it indicates that step S340 is not true, and then proceeds to step S360. The ADC 120 does not adjust the sampling frequency and samples the downlink signal to provide sampled data, and the processor 130 performs touch sensing based on this sampled data.

[0029] In summary, the touch display device, touch display system, and operating method described in this embodiment of the invention involve the processor in the touch display device first reducing the carrier frequency of the downlink signal of the active stylus by using an uplink signal when the touch display device transitions from a high-frequency operating mode to a low-frequency operating mode. The processor dynamically adjusts the sampling frequency of the ADC and determines whether the signal-to-noise ratio (SNR) in the sampled data provided by the ADC is higher than that required by the touch display system. This reduces the sampling frequency or the number of sampling data of the ADC to save power consumption of the ADC and subsequent digital circuits, thereby making the touch display device more energy-efficient overall.

[0030] 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; and these 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: A signal receiver receives downlink signals from an active stylus, wherein the downlink signals include analog touch signals; An analog-to-digital converter, coupled to the signal receiver, converts the analog touch signal into sampled data; A signal transmitter sends an uplink signal to the active stylus, wherein the carrier frequency of the downlink signal provided by the active stylus is adjusted based on the uplink signal; as well as The processor is coupled to the analog-to-digital converter and the signal transmitter. In the low-frequency operation mode of the touch display device, the processor reduces the carrier frequency of the downlink signal provided by the active stylus via the signal transmitter and the uplink signal. The processor reduces the sampling frequency of the analog-to-digital converter and performs touch sensing based on the sampled data. The processor includes: A touch signal processor, coupled to the analog-to-digital converter, receives the sampled data sampled by the analog-to-digital converter; A signal-to-noise ratio (SNR) adjuster, coupled to the touch signal processor, calculates the SNR of the sampled data based on the sampled data, and compares the SNR with an initial SNR range to generate a comparison result; and A timing controller, coupled to the signal-to-noise ratio adjuster, provides an uplink carrier frequency adjustment signal to the signal transmitter based on the comparison result, and adjusts the sampling frequency of the analog-to-digital converter.

2. The touch display device according to claim 1, characterized in that, In the high-frequency operation mode of the touch display device, the processor sets the carrier frequency of the downlink signal provided by the active stylus to a first carrier frequency value through the signal transmitter and the uplink signal, and sets the sampling frequency of the analog-to-digital converter to a first sampling frequency value.

3. The touch display device according to claim 2, characterized in that, When the touch display device enters the low-frequency operating mode from the high-frequency operating mode, the processor adjusts the carrier frequency of the downlink signal provided by the active stylus from the first carrier frequency value to the second carrier frequency value through the signal transmitter and the uplink signal, wherein the first carrier frequency value is higher than the second carrier frequency value.

4. The touch display device according to claim 1, characterized in that, The processor dynamically determines whether to adjust the sampling frequency of the analog-to-digital converter based on the signal-to-noise ratio of the sampled data.

5. The touch display device according to claim 1, characterized in that, The processor reduces the number of data processing operations of the analog-to-digital converter to lower the sampling frequency of the analog-to-digital converter.

6. The touch display device according to claim 1, characterized in that, The signal-to-noise ratio of the touch display device in the low-frequency operating mode is greater than or equal to the signal-to-noise ratio in the high-frequency operating mode.

7. A method for operating a touch display device, characterized in that, include: Obtain a downlink signal from an active stylus, wherein the downlink signal includes an analog touch signal; The analog touch signal is converted into sampled data using an analog-to-digital converter, and touch sensing is performed based on the sampled data. In the low-frequency operation mode of the touch display device, a processor uses an uplink signal to reduce the carrier frequency of the downlink signal provided by the active stylus; and The processor reduces the sampling frequency of the analog-to-digital converter and performs touch sensing based on the sampled data. The processor mentioned above includes: A touch signal processor, coupled to the analog-to-digital converter, receives the sampled data sampled by the analog-to-digital converter; A signal-to-noise ratio (SNR) adjuster, coupled to the touch signal processor, calculates the SNR of the sampled data based on the sampled data, and compares the SNR with an initial SNR range to generate a comparison result; and A timing controller, coupled to the signal-to-noise ratio adjuster, provides an uplink carrier frequency adjustment signal to the signal transmitter based on the comparison result, and adjusts the sampling frequency of the analog-to-digital converter.

8. The operating method according to claim 7, characterized in that, Also includes: In the high-frequency operation mode of the touch display device, the carrier frequency of the downlink signal provided by the active stylus is set to a first carrier frequency value by means of the uplink signal, and the sampling frequency of the analog-to-digital converter is set to a first sampling frequency value.

9. The operating method according to claim 8, characterized in that, In the low-frequency operation mode of the touch display device, the step of reducing the carrier frequency of the downlink signal provided by the active stylus via the uplink signal includes: The carrier frequency of the downlink signal provided by the active stylus is adjusted from a first carrier frequency value to a second carrier frequency value via the uplink signal, wherein the first carrier frequency value is higher than the second carrier frequency value.

10. The operating method according to claim 7, characterized in that, The step of reducing the sampling frequency of the analog-to-digital converter includes: The sampling frequency of the analog-to-digital converter is dynamically adjusted based on the signal-to-noise ratio of the sampled data.

11. The operating method according to claim 7, characterized in that, The signal-to-noise ratio of the touch display device in the low-frequency operating mode is greater than or equal to the signal-to-noise ratio in the high-frequency operating mode.

12. The operating method according to claim 7, characterized in that, The number of data processing operations of the analog-to-digital converter is reduced to decrease the sampling frequency of the analog-to-digital converter.

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