TWI854634B - Frequency adjustment method of touch display device - Google Patents

Abstract

A frequency adjustment method of a touch display device includes a following step. When a frequency of a horizontal scanning synchronization signal of a data driving circuit of the touch display device changes, calculate whether is greater than a value according to a frequency f _h of the horizontal scanning synchronous signal and a frequency f _tx of a driving signal of a touch sensing electrode of the touch display device. When is less than the value, adjust a difference between the frequency f _tx of the driving signal of the touch sensing electrode and the frequency f _h of the horizontal scanning synchronization signal of the data driving circuit.

Description

Frequency adjustment method for touch display device

The present invention relates to a frequency adjustment method for an optoelectronic device, and in particular to a frequency adjustment method for a touch display device.

To facilitate user operation, touch sensing electrodes are often provided on display panels. Specifically, after the display panel is completed, a packaging layer is formed on the display panel, and then a touch sensing electrode is formed on the packaging layer. Generally speaking, the thinner the packaging layer, the thinner the display panel can be. However, an overly thin packaging layer makes the distance between the touch sensing electrode and the display panel too close, resulting in excessive parasitic capacitance between the touch sensing electrode and the display panel. The noise of the touch sensing electrode will be coupled to the common electrode and data line of the display panel through the parasitic capacitance between the touch sensing electrode and the display panel, causing the data level written into the storage capacitor to shift during the programming stage, resulting in pixel brightness shift, and thus abnormal water ripples.

The present invention provides a frequency adjustment method for a touch display device, which can improve the water ripple problem.

The frequency adjustment method of the touch display device of the present invention comprises the following steps: when the frequency _fh of the horizontal scanning synchronization signal of the data driving circuit of the touch display device changes, the frequency _fh of the horizontal scanning synchronization signal and the frequency _ftx of the driving signal of the touch sensing electrode of the touch display device are adjusted. Is it greater than a value? When the above value is reached, the difference between the frequency f _tx of the driving signal of the touch sensing electrode and the frequency f _h of the horizontal scanning synchronization signal of the data driving circuit is adjusted.

In one embodiment of the present invention, when When the value is reached, the frequency f _tx of the driving signal of the touch sensing electrode is adjusted.

In one embodiment of the present invention, the frequency f _tx of the driving signal of the touch sensing electrode is adjusted, preferably selected from the range of f _h < f _tx .

In one embodiment of the present invention, the above values are , where f _h is the frequency of the horizontal scanning synchronization signal of the data driving circuit, P is the display pixel pitch of the touch display device, φ is 0.00147 rad , and D is a viewing distance of the touch display device.

In one embodiment of the present invention, when the value .

In an embodiment of the present invention, the viewing distance is obtained by using a distance sensing device to obtain the distance between a human eye and the touch display device.

In an embodiment of the present invention, the frequency adjustment method of the touch display device further includes: when the screen update frequency of the touch display device changes, determining whether the frequency _fh of the horizontal scanning synchronization signal changes.

In an embodiment of the present invention, the frequency adjustment method of the touch display device further includes: when the resolution setting of the touch display device is changed, determining whether the frequency _fh of the horizontal scanning synchronization signal is changed.

In an embodiment of the present invention, the frequency _fh of the horizontal scanning synchronization signal of the data driving circuit and the frequency _ftx of the driving signal of the touch sensing electrode satisfy: _0.5fh < _ftx < _1.5fh .

In one embodiment of the present invention, When the value is greater than the above value, normal human eyes cannot distinguish the water ripples generated by the touch display device.

FIG. 1 is a schematic diagram of a touch display device in an embodiment of the present invention from a top view. FIG. 2 is a schematic diagram of a partial enlargement of a touch display device in an embodiment of the present invention. FIG. 2 corresponds to the partial R of FIG. 1. FIG. 3 is a schematic diagram of a cross-section of a touch display device in an embodiment of the present invention. FIG. 4 is a schematic diagram of the timing of the horizontal scanning synchronization signal of the data drive circuit and the drive signal of the touch sensing electrode in an embodiment of the present invention.

1, 2 and 3, the touch display device 10 includes a display panel 100. The display panel 100 includes a data driving circuit IC and a plurality of pixels PX. In one embodiment, each pixel PX may include a data line 110, a scanning line 120, a pixel driving circuit (not shown), a pixel electrode 130, a display medium 140 and a common electrode 150, wherein the pixel driving circuit has at least one active element, a first end and a control end of the at least one active element (e.g., at least one thin film transistor) are electrically connected to the data line 110 and the scanning line 120, respectively, the pixel electrode 130 is electrically connected to the second end of the at least one active element, and the display medium 140 is disposed between the pixel electrode 130 and the common electrode 150. In one embodiment, a storage capacitor _Cst of the pixel PX may be provided between the data line 110 and the common electrode 150. The data driving circuit IC is electrically connected to a plurality of data lines 110 of a plurality of pixels PX. Referring to FIG. 1 and FIG. 4 , the data driving circuit IC has a horizontal scanning synchronization signal Hsync.

For example, in one embodiment, the display medium 140 may be an organic light emitting diode pattern, and the display panel 100 may be an organic light emitting diode display panel. However, the present invention is not limited thereto, and in other embodiments, the display panel 100 may also be other types of display panels, such as a liquid crystal display panel, micro light emitting diode (μLED), etc.

3 , the touch sensing electrode 200 and the pixel PX at least partially overlap. 3 and 4 , the touch sensing electrode 200 has a driving signal Tx. In detail, in one embodiment, the touch portion of the touch display device 10 may adopt a mutual capacitance design, and the touch sensing electrode 200 may include a transmitting electrode and a receiving electrode, wherein the transmitting electrode has the driving signal Tx.

1, 2 and 3, the noise of the touch sensing electrode 200 is coupled to the common electrode 150 and the data line 110 of the display panel 100 through the parasitic capacitor C _TC between the touch sensing electrode 200 and the display panel 100, so that the data level of the storage capacitor C _st written into the pixel PX in the programming stage is shifted, resulting in the brightness shift of the pixel PX, and thus causing abnormal water ripples M to appear on the 128 grayscale screen. A plurality of scanning lines 120 are arranged in the direction y. The water ripple M includes a plurality of darkest lines Mb1, Mb2 and a plurality of brightest lines Mw arranged alternately in the direction y, wherein the same row of pixels PX shares the same scanning line 120, and each of the plurality of darkest lines Mb1, Mb2 and the plurality of brightest lines Mw corresponds to the same row of pixels PX. Two adjacent darkest lines Mb1, Mb2 of the water ripple M have a distance D _M in the direction y. Once the distance D _M is less than the minimum resolvable distance of the normal human eye, the human eye cannot distinguish the difference between the darkest line and the brightest line, that is, the water ripple M is invisible.

Please refer to FIG. 1, FIG. 2 and FIG. 4. The distance DM between the two adjacent darkest lines Mb1 and Mb2 of the water ripple _M is related to the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 and the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC. In other words, the water ripple M can be made invisible by properly adjusting/setting the frequency _ftx of the driving signal Tx and/or the frequency _fh of the horizontal scanning synchronization signal Hsync, which is explained below with reference to FIG. 1, FIG. 2, FIG. 3, FIG. 4 and FIG. 5.

Referring to FIG. 1, FIG. 2, FIG. 3 and FIG. 4, in one embodiment, when the driving signal Tx of the touch sensing electrode 200 changes from a low level to a high level and the time point _tb1 , _tb2 of the change is close to the next activation time _tonb1 , _tonb2 of the horizontal scanning synchronization signal Hsync, the data level of the storage capacitor _Cst of the corresponding row of pixels PX will be affected by the driving signal Tx and shifted, causing the row of pixels PX to present abnormal darkest lines Mb1, Mb2; when the driving signal Tx changes from a high level to a low level and the time point tw of the change is close to the next activation time tonw of the horizontal scanning synchronization signal Hsync, the storage capacitor Cst of the corresponding row of pixels PX will be affected by the driving signal Tx and shifted, causing the row of pixels PX to present abnormal darkest lines Mb1, Mb2; when the driving signal Tx changes from a high level to a low level and the time point tw of the change _is close to the next activation time _tonw of the horizontal scanning synchronization signal Hsync, the storage capacitor Cst of the corresponding row of pixels PX will be shifted. The data level of _st will be shifted by the driving signal Tx, causing the row of pixels PX to present an abnormal brightest line Mw.

The frequency of the horizontal scanning synchronization signal Hsync is f _h . The period of the horizontal scanning synchronization signal Hsync is 1/ f _h . The frequency of the driving signal Tx of the touch sensing electrode 200 is f _tx . The period of the driving signal Tx is 1/ f _tx . ---Formula (1), wherein P is the display pixel pitch of the plurality of pixels PX of the touch display device 10 in the direction y, _fh is the frequency of the horizontal scanning synchronization signal Hsync of the data driving circuit IC, and _ftx is the frequency of the driving signal Tx of the touch sensing electrode 200. In this embodiment, _DM in formula (1) may refer to the distance between the two adjacent darkest lines Mb1 and Mb2 of the water ripple M. However, the present invention is not limited thereto, and in another embodiment, _DM in formula (1) may also refer to the distance between the two adjacent brightest lines Mw of the water ripple M.

FIG5 shows the angular resolution of a normal human eye and a touch display device of an embodiment of the present invention. Referring to FIG5 , according to the Snellen chart, the naked eye vision of a normal human eye E is 1.0, and the normal human eye E can see an image of 8.8 mm at least at a distance of 6 m. In other words, the angular resolution φ of the normal human eye E is 0.00147 rad. When the viewing distance of the touch display device 10 (i.e., the distance from the human eye E to the touch display device 10) is D, the minimum resolvable distance of the normal human eye is ---Formula (2).

When the distance D _M between the two adjacent darkest lines Mb1 and Mb2 of the water ripple M in the direction y is less than the minimum resolvable distance _De of the normal human eye E, the water ripple M is invisible. In other words, D _M and _De satisfy equation (3): When D _M < _De , the water ripple M is invisible. Substituting equations (1) and (2) into equation (3), we can obtain equation (4): From formula (4), we can derive formula (5): , where P is the display pixel pitch of the multiple pixels PX of the touch display device 10 in the direction y, f _h is the frequency of the horizontal scanning synchronization signal Hsync of the data driving circuit IC, D is the viewing distance of the touch display device 10 (i.e., the distance from the human eye E to the touch display device 10), φ is the angular resolution of the normal human eye E (i.e., 0.00147 rad), and f _tx is the frequency of the driving signal Tx of the touch sensing electrode 200. It can be seen from formula (5) that if the absolute value of the difference between the frequency f _h of the horizontal scanning synchronization signal Hsync and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 is less than Then the water ripples M can be made invisible.

For example, in one embodiment, the touch display device 10 can be applied to a mobile phone. Assuming that the viewing distance D of the mobile phone is about 30 cm, the absolute value of the difference between the frequency f _h of the horizontal scanning synchronization signal Hsync and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 that can make the water ripple M invisible under various display sizes, various frame rates, and various resolutions is The minimum value of is shown in Table 1 below. From the data in Table 1, it can be seen that at a viewing distance D of about 30 cm, in most mobile phone applications, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driver IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 meet: 34KHz＜| f _h - f _tx |, which can make the water ripple M invisible. Specifically, at a viewing distance D of about 30 cm, in most mobile phone applications, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 can satisfy: f _h +34KHz < f _tx or f _tx < f _h -34KHz. Furthermore, in one embodiment, the driving signal Tx of the touch sensing electrode 200 has a better touch experience in the range of 0.5 _fh < _ftx <1.5 _fh , and the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 can satisfy: _fh +34KHz < _ftx < _1.5fh or 0.5fh < _{ftx < fh} -34KHz. Display size(inch) 6.7 6.4 6.16 6.7 Frame refresh rate (Hz) 120 90 120 144 Resolution(PPI) (KHz) 47 34 43 57 [Table 1]

In another embodiment, the touch display device 10 can be applied to a mobile phone and the viewing distance D is about 50 cm. The frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 satisfy: 20KHz＜| f _h - f _tx |, so that the water ripple M can be invisible. More specifically, in the mobile phone application with a viewing distance D of about 50 cm, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 satisfy: f _h +20KHz＜ f _tx or f _tx ＜ f _h -20KHz. Furthermore, in one embodiment, the driving signal Tx of the touch sensing electrode 200 has a better touch experience in the range of 0.5 _fh < _ftx <1.5 _fh , and the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 satisfy: _fh +20KHz < _ftx < _1.5fh or 0.5fh < ftx < _{fh -20KHz .}

In another embodiment, the touch display device 10 can be applied to a tablet. Assuming that the viewing distance D of the tablet is about 30 cm, the absolute value of the difference between the frequency f _h of the horizontal scanning synchronization signal Hsync and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 that can make the water ripple M invisible under various display sizes, various frame update rates and various resolutions is The minimum value is shown in Table 2 below. Based on the data in Table 2, it can be seen that when the viewing distance D is about 30 cm, in most tablet applications, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driver IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 meet: 30KHz＜| f _h - f _tx |, which can make the water ripple M invisible. Specifically, in most tablet applications where the viewing distance D is about 30 cm, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driver IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 can satisfy: f _h +30KHz < f _tx or f _tx < f _h -30KHz. Furthermore, in one embodiment, the driving signal Tx of the touch sensing electrode 200 has a better touch experience in the range of 0.5 _fh < _ftx <1.5 _fh , and the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 can satisfy: _fh +30KHz < _ftx < _1.5fh or 0.5fh < _{ftx < fh} -30KHz. Display size(inch) 12.4 12.6 12.6 Frame refresh rate (Hz) 120 60 120 Resolution(PPI) (KHz) 60 30 61 [Table 2]

In another embodiment, the touch display device 10 can be applied as a tablet and the viewing distance D is about 50 cm. The frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 satisfy: 18KHz＜| _fh - _ftx |, so that the water ripples M can be invisible. Specifically, in most tablet applications where the viewing distance D is about 50 cm, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driver IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 can satisfy: f _h +18KHz＜ f _tx or f _tx ＜ f _h -18KHz. Furthermore, in one embodiment, the driving signal Tx of the touch sensing electrode 200 has a better touch experience in the range of 0.5 _fh < _ftx <1.5 _fh , and the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 can satisfy: _fh +18KHz < _ftx < _1.5fh or 0.5fh < _{ftx < fh} -18KHz.

When the screen update frequency, resolution setting or viewing distance D of the touch display device 10 changes, the water ripples M may become invisible. At this time, it can be determined whether the frequency of the touch display device 10 needs to be adjusted to avoid the water ripple M problem. The following is an example of the adjustment method with reference to FIG. 6 , FIG. 7 and FIG. 8 .

FIG6 is a flowchart of a frequency adjustment method for a touch display device according to an embodiment of the present invention. Referring to FIG3, FIG4, FIG5 and FIG6, when the screen update frequency of the touch display device 10 is switched (i.e., the screen update frequency changes), first, step S11 is performed: determining whether the frequency _fh of the horizontal scanning synchronization signal Hsync changes; if it is determined that the frequency _fh of the horizontal scanning synchronization signal Hsync changes, then the frequency _fh of the horizontal scanning synchronization signal Hsync and a frequency _ftx of the driving signal Tx of the touch sensing electrode 200 of the touch display device 10 are adjusted. Is it greater than a value? When the value is set, the difference between the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 and the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC is adjusted. Specifically, in this embodiment, the value can be , where f _h is the frequency of the horizontal scanning synchronization signal Hsync of the data driving circuit IC, P is the display pixel pitch of the touch display device 10, φ is 0.00147rad , and D is the viewing distance of the touch display device 10. When performing step S11, if it is determined that the frequency f _h of the horizontal scanning synchronization signal Hsync changes, then step S12 is performed: according to whether the changed frequency f _h of the horizontal scanning synchronization signal Hsync and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 do not meet , to determine whether to adjust the difference between the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 and the frequency f _h of the horizontal scanning synchronization signal Hsync of the changed data driving circuit IC; in this embodiment, if it is determined that the frequency f _h of the horizontal scanning synchronization signal Hsync of the changed data driving circuit IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 do not satisfy , then proceed to step S13: adjust the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 so that the changed frequency f _h of the horizontal scanning synchronization signal Hsync and the adjusted frequency f _tx of the driving signal Tx satisfy Thus, when the screen update frequency of the touch display device 10 is switched, the water ripples M can be ensured to be invisible (ie, the normal human eye E cannot distinguish the water ripples M generated by the touch display device 10). In one embodiment, the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 can be preferentially selected from the range of f _h < f _tx . In one embodiment, the driving signal Tx of the touch sensing electrode 200 has a better touch experience in the range of 0.5 _fh < _ftx <1.5 _fh , and the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 can satisfy: 0.5 _fh < _ftx <1.5 _fh .

FIG7 is a flowchart of a frequency adjustment method for a touch display device according to another embodiment of the present invention. Referring to FIG3, FIG4, FIG5 and FIG7, when the resolution of the touch display device 10 is switched (i.e., the resolution setting is changed), first, step S21 is performed: determining whether the frequency _fh of the horizontal scanning synchronization signal Hsync has changed. If it is determined that the frequency _fh of the horizontal scanning synchronization signal Hsync has changed, the frequency _fh of the horizontal scanning synchronization signal Hsync and a frequency _ftx of the driving signal Tx of the touch sensing electrode 200 of the touch display device 10 are adjusted. Is it greater than a value? When the value is set, the difference between the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 and the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC is adjusted. Specifically, in this embodiment, the value can be , wherein f _h is the frequency of the horizontal scanning synchronization signal Hsync of the data driving circuit IC, P is the display pixel pitch of the touch display device 10, φ is 0.00147rad , and D is the viewing distance of the touch display device 10. When performing step S21, if it is determined that the frequency f _h of the horizontal scanning synchronization signal Hsync changes, then step S22 is performed: according to whether the changed frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 do not meet , to determine whether to adjust the difference between the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 and the frequency f _h of the horizontal scanning synchronization signal Hsync of the changed data driving circuit IC; in this embodiment, if it is determined that the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 and the frequency f _h of the horizontal scanning synchronization signal Hsync of the changed data driving circuit IC do not meet , then proceed to step S23: adjust the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 so that the changed frequency f _h of the horizontal scanning synchronization signal Hsync and the adjusted frequency f _tx of the driving signal Tx satisfy Thereby, when the resolution of the touch display device 10 is switched, it can be ensured that the water ripples M are invisible. In this embodiment, the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 is adjusted, and can be preferentially selected from the range of f _h < f _tx .

FIG8 is a flowchart of a frequency adjustment method of a touch display device according to another embodiment of the present invention. Referring to FIG1, FIG3, FIG4, FIG5 and FIG8, when the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC of the touch display device 10 changes, the frequency _fh of the horizontal scanning synchronization signal Hsync and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 of the touch display device 10 are adjusted. Is it greater than a value? When the value is set, the difference between the frequency f _tx of the driving signal Tx of the touch sensing electrode 200 and the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC is adjusted. In this embodiment, the value can be , where f _h is the frequency of the horizontal scanning synchronization signal Hsync of the data drive circuit IC, P is the display pixel pitch of the touch display device 10, φ is 0.00147rad , and D is the viewing distance of the touch display device 10. .

Please refer to FIG. 3, FIG. 4, FIG. 5 and FIG. 8 for details. In this embodiment, when the viewing distance D of the touch display device 10 changes (ie, the value ), then proceed to step S31: determine whether the changed viewing distance D, the frequency _fh of the horizontal scanning synchronization signal Hsync of the data drive circuit IC, and the frequency _ftx of the drive signal Tx of the touch sensing electrode 200 do not satisfy (Right now ). In this embodiment, the viewing distance D can be obtained by a distance sensing device to obtain the distance between a human eye and the touch display device 10. If it is determined that the changed viewing distance D, the frequency _fh of the horizontal scanning synchronization signal Hsync of the data driving circuit IC and the frequency _ftx of the driving signal Tx of the touch sensing electrode 200 do not meet , then proceed to step S32: adjust the difference between the frequency f _h of the horizontal scanning synchronization signal Hsync of the data drive circuit IC and the frequency f _tx of the drive signal Tx of the touch sensing electrode 200 to satisfy Thus, when the viewing distance D of the touch display device 10 changes, the water ripples M can be ensured to be invisible. In this embodiment, the frequency f _h of the horizontal scanning synchronization signal Hsync of the data driving circuit IC, the frequency f _tx of the driving signal Tx of the touch sensing electrode 200, or both of them can be adjusted to meet .

10: Touch display device

100: Display panel

110: Data line

120: Scan line

130: Pixel electrode

140: Display media

150: Common electrode

200: Touch sensing electrode

C _st : Storage capacitor

C _TC : Parasitic capacitance

D: Viewing distance

_De : Minimum resolvable distance

D _M :Distance

E: Normal human eye

f _h , f _tx : frequency

Hsync: horizontal scanning synchronization signal

M: Water ripples

Mb1, Mb2: darkest line

Mw: Brightest line

P: Display pixel pitch

PX: Pixel

R: Local

S11, S12, S13, S21, S22, S23, S31, S32: Steps

Tx: driving signal

t _b1 , t _b2 , t _onb1 , t _onb2 , t _w : time points

t _onw : start time

IC: Data driver circuit

y: direction

φ: Angular resolution

FIG. 1 is a schematic diagram of a touch display device of an embodiment of the present invention from a top view. FIG. 2 is a schematic diagram of a partial enlargement of a touch display device of an embodiment of the present invention. FIG. 3 is a schematic diagram of a cross-section of a touch display device of an embodiment of the present invention. FIG. 4 is a schematic diagram of a timing sequence of a horizontal scanning synchronization signal of a data drive circuit and a drive signal of a touch sensing electrode of an embodiment of the present invention. FIG. 5 shows the angular resolution of a normal human eye and a touch display device of an embodiment of the present invention. FIG. 6 is a schematic diagram of a flow chart of a frequency adjustment method of a touch display device of an embodiment of the present invention. FIG. 7 is a schematic diagram of a flow chart of a frequency adjustment method of a touch display device of another embodiment of the present invention. FIG8 is a flow chart of a frequency adjustment method of a touch display device according to another embodiment of the present invention.

S11, S12, S13: Steps

Claims (9)

A frequency adjustment method for a touch display device includes: when a frequency fh of a horizontal scanning synchronization signal of a data driving circuit of a touch display device changes, calculating _whether | _fh - _{ftx| is greater than a value according to the frequency fh of the horizontal scanning synchronization signal and a frequency ftx of a} driving signal of a touch sensing electrode of the touch display device; when | fh - ftx | is less than the value, adjusting the frequency ftx of the driving signal of the touch sensing electrode to adjust _the frequency ftx _of the driving _signal of the touch sensing electrode . _tx and the _frequency fh of the horizontal scanning synchronization signal of the data driving circuit. In the frequency adjustment method of the touch display device as described in claim 1, the frequency f _tx of the driving signal of the touch sensing electrode is adjusted, and is preferentially selected from the range of f _h < f _tx . In the frequency adjustment method of the touch display device as described in claim 1, the value is

, wherein f _h is the frequency of the horizontal scanning synchronization signal of the data driving circuit, P is a display pixel pitch of the touch display device, φ is 0.00147 rad, and D is a viewing distance of the touch display device. In the frequency adjustment method of the touch display device as described in claim 3, when the value

When it changes, recalculate whether | f _h - f _tx | satisfies

<| f _h - f _tx |. In the frequency adjustment method of the touch display device as described in claim 3, the viewing distance is obtained by a distance sensing device to obtain the distance between a human eye and the touch display device. The frequency adjustment method of the touch display device as described in claim 1 further includes: when a frame update frequency of a touch display device changes, determining _whether the frequency fh of the horizontal scanning synchronization signal changes. The frequency adjustment method of the touch display device as described in claim 1 further includes: when a resolution setting of the touch display device is changed, determining whether the _frequency fh of the horizontal scanning synchronization signal is changed. The frequency adjustment method of the touch display device as described in claim 1, wherein the frequency fh of the horizontal scanning _{synchronization} signal of the _data driving circuit and the frequency ftx of the driving signal of the touch sensing electrode satisfy: _0.5fh < _ftx < 1.5fh _. In the frequency adjustment method of the touch display device as described in claim 1, when | fh _- ftx | is greater than the value, a normal human eye cannot distinguish a water ripple generated _by the touch display device.

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