CN117435080A - Active pen receiving circuit and touch panel system using active pen - Google Patents
Active pen receiving circuit and touch panel system using active pen Download PDFInfo
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- CN117435080A CN117435080A CN202210816323.2A CN202210816323A CN117435080A CN 117435080 A CN117435080 A CN 117435080A CN 202210816323 A CN202210816323 A CN 202210816323A CN 117435080 A CN117435080 A CN 117435080A
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- digital signal
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- active pen
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- 238000003780 insertion Methods 0.000 claims abstract description 33
- 230000037431 insertion Effects 0.000 claims abstract description 33
- 238000005070 sampling Methods 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims description 8
- 230000005540 biological transmission Effects 0.000 claims 2
- 238000010586 diagram Methods 0.000 description 6
- 239000007787 solid Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
Classifications
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/044—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means
- G06F3/0441—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means by capacitive means using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
- G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
- G06F3/03545—Pens or stylus
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
- G06F3/0412—Digitisers structurally integrated in a display
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Human Computer Interaction (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Position Input By Displaying (AREA)
Abstract
An active pen receiving circuit receives a vector data signal sent by an active pen, wherein the vector data signal carries vector data, the vector data comprises in-phase data and quadrature data, and the active pen receiving circuit comprises an analog-digital converter, an insertion point circuit and a demodulation circuit. The analog-to-digital converter samples the vector data signal and converts the sampled vector data signal into a digital signal having a plurality of sampling points. The insertion point circuit performs insertion point operation on the digital signal to increase the number of sampling points representing the digital signal and generate the digital signal after insertion point. The demodulation circuit demodulates the digital signal after the insertion point to generate demodulated in-phase data and demodulated quadrature data, thereby obtaining demodulated vector data.
Description
Technical Field
The present invention relates to the technical field of active pens, and more particularly, to an active pen receiving circuit and a touch panel system using the same.
Background
Active pens (Active stylus) have been widely used to cooperate with electronic devices having touch panels to provide input effects, wherein the Active pen has a transmitting circuit therein for transmitting modulated (modulated) vector data signals for receiving by the touch panel to detect the coordinates of the Active pen. In order to correctly receive and demodulate (demodulate) the vector data signal sent by the active pen, a plurality of sensors are arranged on the touch panel to sense the vector data signal, and a corresponding receiving circuit is used for receiving the vector data signal to demodulate to obtain vector data.
In the process of modulating, transmitting, receiving and demodulating the vector data, the active pen modulates the vector data with carrier wave, for example, wherein the vector data comprises in-phase data and quadrature data, the modulated vector data signals are sent out by the active pen to be received by corresponding receiving circuits, the receiving circuits convert the received vector data signals into digital signals by analog-to-digital converters (ADC), and then demodulate the digital signals by the in-phase carrier wave and the quadrature carrier wave respectively, so as to demodulate the in-phase data and the quadrature data, and obtain the original vector data.
In the operation process of the touch panel using the active pen, one of the main reasons for influencing the performance of the active pen is the data sampling rate of the analog-to-digital converter of the receiving circuit, and the active pen is more excellent in noise resistance performance when the sampled data is more, whereas the active pen is easily interfered by noise when the sampled data is less. Therefore, under the condition of limited sampling rate of the analog-digital converter, a lot of hardware area is required to meet the specification of the active pen, and the actual requirement cannot be met.
Therefore, there are many drawbacks in the design of the existing active pen receiving circuit, and there is still a need for improvement.
Disclosure of Invention
The invention mainly aims at providing an active pen receiving circuit and a touch panel system using the same, which can effectively improve the efficiency of an active pen, increase the anti-interference and anti-noise capacity and reduce the area of a front-end analog circuit by using an active pen insertion point technology.
According to an aspect of the present invention, an active pen receiving circuit is provided for receiving a vector data signal sent by an active pen, the vector data signal carrying vector data, the vector data including in-phase data and quadrature data, the active pen receiving circuit comprising: an analog-to-digital converter for sampling the vector data signal and converting the vector data signal into a digital signal with a plurality of sampling points; the inserting point circuit is used for carrying out inserting point operation on the digital signal so as to increase the number of sampling points representing the digital signal and generate a digital signal after inserting point; and a demodulation circuit for demodulating the digital signal after the insertion point to generate demodulated in-phase data and demodulated quadrature data, thereby obtaining demodulated vector data.
According to another aspect of the present invention, a touch panel system is provided, which includes: an active pen for emitting vector data signal carrying vector data, wherein the vector data comprises in-phase data and quadrature data; a touch panel having a plurality of sensors for sensing the vector data signal emitted from the active pen; and a receiving device having a plurality of active pen receiving circuits, each of the active pen receiving circuits corresponding to at least one sensor and comprising: an analog-to-digital converter for sampling the vector data signal and converting the vector data signal into a digital signal with a plurality of sampling points; an inserting point circuit for carrying out inserting point operation on the digital signal to increase the number of sampling points representing the digital signal so as to generate a digital signal after inserting point; and a demodulation circuit for demodulating the digital signal after the insertion point to generate demodulated in-phase data and demodulated quadrature data, thereby obtaining demodulated vector data.
The foregoing summary and the following detailed description are exemplary in nature and are intended to provide further explanation of the invention as well as additional objects and advantages of the invention as set forth in the following description and drawings.
Drawings
Fig. 1 shows a touch panel system using an active pen according to the present invention.
Fig. 2 shows a schematic diagram of the active pen transmitting vector data signals.
Fig. 3 is a schematic diagram of an active pen receiving circuit.
Fig. 4 is a schematic diagram of the demodulation circuit after demodulating the digital signal at the insertion point.
Symbol description:
tip 11 of active pen 10
Touch panel 20 of pen ring 13
Receiving device 30 active pen receiving circuit 31
Sensor Sx microcontroller 50
Analog-to-digital converter 311 of integrated circuit 60
The add-point circuit 313 demodulates the circuit 315
Sampling points 35, 351, 352
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific examples described herein are for purposes of illustration only and are not intended to limit the scope of the present invention.
Fig. 1 shows a touch panel system using an active pen according to the present invention, which includes an active pen 10, a touch panel 20, and a receiving device 30, wherein the receiving device 30 is disposed in an Integrated Circuit (IC) 60, and the integrated circuit 60 further has a Micro Controller (MCU) 50. The active pen 10 has a pen Tip (Tip) 11 and a pen Ring (Ring) 13, and emits a vector data signal at an emission frequency fin, the touch panel 20 has a plurality of sensors Sx, and senses the vector data signal emitted from the pen Tip 11 or pen Ring 13 of the active pen 10, and the receiving device 30 has a plurality of active pen receiving circuits 31 for receiving the vector data signal X (t) and processing the received vector data signal X (t) to obtain vector data emitted from the active pen. It should be noted that the touch panel 20 in the present embodiment may be an in-cell touch display panel, a stand-alone touch panel, or other electronic devices with similar functions.
Fig. 2 shows a schematic diagram of the active pen 10 transmitting a vector data signal X (t), where the active pen 10 modulates (modulates) the vector data X (t) with, for example, a carrier signal cos (ωt) +sin (ωt) having an in-phase modulated carrier signal cos (ωt) and a quadrature modulated carrier signal sin (ωt) so that the vector data X (t) carries the vector data X (t), and the vector data X (t) includes in-phase data xi (t) and quadrature data xq (t), and the modulated vector data X (t) =xi (t) ×cos (ωt) +xq (t) sin (ωt) is emitted from the pen tip 11 or the pen ring 13 of the active pen 10.
Referring to fig. 1 and 2 together, the sensor Sx of the touch panel 20 can sense the vector data signal X (t) sent by the pen tip 11 or the pen ring 13 of the active pen 10 and is received by the corresponding active pen receiving circuit 31 of the receiving device 30, wherein each active pen receiving circuit 31 corresponds to at least one sensor Sx, and one active pen receiving circuit 31 can receive the vector data signals X (t) sensed by a plurality of sensors Sx in a multitasking manner.
Fig. 3 is a schematic diagram of the active pen receiving circuits 31, as shown in the drawing, each active pen receiving circuit 31 has an analog-to-digital converter (ADC) 311, an inserting point circuit 313 and a demodulating circuit 315, wherein the ADC 311 samples and converts the received vector data signal X (t) into an n-bit digital signal X (n) =xi (n) ×cos ((2pi×n×fin)/fs) +xq (n) ×sin ((2pi×n×fin)/fs), where fs is the sampling frequency of the ADC 311, fin is the transmitting frequency of the vector data signal X (t) transmitted by the active pen 10, and the sampled and converted digital signal has a plurality of sampling points 35.
In order to increase the performance of the active pen 10 and increase the anti-noise capability and reduce the circuit area, the insertion point circuit 313 is further used to perform the insertion point operation on the digital signal X (n) in the active pen receiving circuit 31, so that the number of the sampling points 35 representing the digital signal X (n) is increased, as shown in fig. 3, the sampling points 351 originally representing the digital signal X (n) are shown by solid circles, and since the solid circles have sparse distribution of the sampling points 351, the digital signal X (t) may not be fully represented, the insertion point circuit 313 is used to perform the insertion point operation on the digital signal X (n), so that the sampling points 352 represented by open circles are inserted between the sampling points 351 of the solid circles, so that the distribution of the whole sampling points 35 becomes compact, and thus the digital signal X (t) after the insertion point operation on the digital signal X (n) can be fully represented by the solid circles in one embodiment of the invention:
where Y () represents the digital signal after the insertion point, X () represents the digital signal output by the digitizer 311, and floor () represents the floor function. For example, Y (1) =x (1), Y (2) = (X (1) +x (2))/2, Y (3) =x (2), Y (4) = (X (3) +x (4))/2, and so on.
The foregoing inserting point circuit 313 may use any inserting point operation technique to perform inserting point on the digital signal X (n), for example, the two-point interpolation method described in the foregoing embodiment, but the present invention is not limited thereto, and the inserting point operation adopted by the inserting point circuit 313 may be various inserting point methods such as a polynomial interpolation method or an original value interpolation method, and the implementation manner thereof is known to those skilled in the art, so that the description is omitted.
Referring to fig. 3 again, the digital signal Y (m) after the insertion point is demodulated by the demodulation circuit 315 to generate demodulated vector data x_rx, fig. 4 shows a schematic diagram of the demodulation circuit 315 demodulating the digital signal Y (m) after the insertion point, wherein the demodulation circuit 315 demodulates the digital signal Y (m) after the insertion point by the in-phase modulated carrier signal cos (ωt) to generate demodulated in-phase data xi_rx, and demodulates the digital signal Y (m) after the insertion point by the quadrature modulated carrier signal sin (ωt) to generate demodulated quadrature data xq_rx, so as to obtain demodulated vector data x_rx=xi_rx+xq_rx, and the demodulated vector data x_rx=xi_rx+xq_rx is transmitted to the microcontroller 50 as shown in fig. 1 for operation to obtain active pen coordinate data.
Therefore, the invention can carry out the insertion point operation on the digital signal output by the analog-digital converter by the insertion point circuit, so that the number of sampling points representing the digital signal is increased, and the vector data signal can be completely represented, thereby effectively improving the efficiency of the active pen, enhancing the anti-interference and anti-noise capability and reducing the circuit area.
The above embodiments are merely illustrative, and the scope of the invention is defined by the claims and not limited to the above embodiments.
Claims (12)
1. An active pen receiving circuit for receiving a vector data signal from an active pen, the vector data signal carrying vector data comprising in-phase data and quadrature data, the active pen receiving circuit comprising:
an analog-to-digital converter for sampling the vector data signal and converting the vector data signal into a digital signal with a plurality of sampling points;
the inserting point circuit is used for carrying out inserting point operation on the digital signal so as to increase the number of sampling points representing the digital signal and generate a digital signal after inserting point; and
and a demodulation circuit for demodulating the digital signal after the insertion point to generate demodulated in-phase data and demodulated quadrature data, thereby obtaining demodulated vector data.
2. The active pen receiving circuit of claim 1, wherein the vector data signal is: xi (t) cos (pi ωt) +xq (t) sin (ωt), wherein xi (t) represents in-phase data, xq (t) represents quadrature data, cos (ωt) represents in-phase modulated carrier signal, and sin (ωt) represents quadrature modulated carrier signal.
3. The active pen receiving circuit of claim 2, wherein the vector data signal is sampled by the digitizer and converted into the digital signal as follows: xi (n) ×cos ((2pi×n×fin)/fs) +xq (n) ×sin ((2pi×n×fin)/fs), where fs is the sampling frequency of the analog-to-digital converter and fin is the transmission frequency of the vector data signal transmitted by the active pen.
4. The active pen receiving circuit of claim 1, wherein the insertion point circuit performs an insertion point operation on the digital signal by a two-point interpolation method.
5. The active pen receiving circuit as claimed in claim 4, wherein the digital signal after the insertion point generated by the insertion point operation of the digital signal by the insertion point circuit is:
wherein Y () represents the digital signal after the insertion point, X () represents the digital signal output by the digitizer, and floor () represents the floor function.
6. The active pen receiving circuit as claimed in claim 1, wherein the demodulation circuit demodulates the digital signal after the add point with an in-phase modulated carrier signal to generate demodulated in-phase data, and demodulates the digital signal after the add point with a quadrature modulated carrier signal to generate demodulated quadrature data, thereby obtaining the demodulated vector data as: xi_rx+xq_rx, where xi_rx represents demodulated in-phase data and xq_rx represents demodulated quadrature data.
7. A touch panel system, comprising:
an active pen for emitting vector data signal carrying vector data, wherein the vector data comprises in-phase data and quadrature data;
a touch panel having a plurality of sensors for sensing the vector data signal emitted from the active pen; and
a receiving device having a plurality of active pen receiving circuits, each of the active pen receiving circuits corresponding to at least one sensor and comprising:
an analog-to-digital converter for sampling the vector data signal and converting the vector data signal into a digital signal with a plurality of sampling points;
an inserting point circuit for carrying out inserting point operation on the digital signal to increase the number of sampling points representing the digital signal so as to generate a digital signal after inserting point; and
and a demodulation circuit for demodulating the digital signal after the insertion point to generate demodulated in-phase data and demodulated quadrature data, thereby obtaining demodulated vector data.
8. The touch panel system of claim 7, wherein the active pen modulates vector data with a carrier signal to generate the vector data signal as: xi (t) cos (pi ωt) +xq (t) sin (ωt), wherein xi (t) represents in-phase data, xq (t) represents quadrature data, cos (ωt) represents in-phase modulated carrier signal, and sin (ωt) represents quadrature modulated carrier signal.
9. The touch panel system of claim 8, wherein the vector data signal is sampled by the digitizer and converted into the digital signal as follows: xi (n) ×cos ((2pi×n×fin)/fs) +xq (n) ×sin ((2pi×n×fin)/fs), where fs is the sampling frequency of the analog-to-digital converter and fin is the transmission frequency of the vector data signal transmitted by the active pen.
10. The touch panel system of claim 7, wherein the interpolation circuit performs interpolation on the digital signal.
11. The touch panel system of claim 10, wherein the digital signal after the insertion point generated by the insertion point operation of the digital signal by the insertion point circuit is:
wherein Y () represents the digital signal after the insertion point, X () represents the digital signal output by the digitizer, and floor () represents the floor function.
12. The touch panel system of claim 7, wherein the demodulation circuit demodulates the digital signal after the add point with an in-phase modulated carrier signal to generate demodulated in-phase data, and demodulates the digital signal after the add point with a quadrature modulated carrier signal to generate demodulated quadrature data, thereby obtaining the demodulated vector data as: xi_rx+xq_rx, where xi_rx represents demodulated in-phase data and xq_rx represents demodulated quadrature data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210816323.2A CN117435080A (en) | 2022-07-12 | 2022-07-12 | Active pen receiving circuit and touch panel system using active pen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210816323.2A CN117435080A (en) | 2022-07-12 | 2022-07-12 | Active pen receiving circuit and touch panel system using active pen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117435080A true CN117435080A (en) | 2024-01-23 |
Family
ID=89556942
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210816323.2A Pending CN117435080A (en) | 2022-07-12 | 2022-07-12 | Active pen receiving circuit and touch panel system using active pen |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117435080A (en) |
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2022
- 2022-07-12 CN CN202210816323.2A patent/CN117435080A/en active Pending
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