CN110633025B - Position detection device and handwriting input system - Google Patents
Position detection device and handwriting input system Download PDFInfo
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- CN110633025B CN110633025B CN201910920770.0A CN201910920770A CN110633025B CN 110633025 B CN110633025 B CN 110633025B CN 201910920770 A CN201910920770 A CN 201910920770A CN 110633025 B CN110633025 B CN 110633025B
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- 238000001514 detection method Methods 0.000 title claims abstract description 47
- 238000000605 extraction Methods 0.000 claims abstract description 14
- 239000003990 capacitor Substances 0.000 claims description 43
- 238000006243 chemical reaction Methods 0.000 claims description 17
- 230000000087 stabilizing effect Effects 0.000 claims description 10
- 238000004804 winding Methods 0.000 claims description 3
- 229910000859 α-Fe Inorganic materials 0.000 claims description 3
- 230000001360 synchronised effect Effects 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 description 8
- 230000005540 biological transmission Effects 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 1
- 238000012905 input function Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000008054 signal transmission 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
- G06F3/0414—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using force sensing means to determine a position
-
- 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
- G06F3/0416—Control or interface arrangements specially adapted for digitisers
Abstract
The invention provides a position detection device and a handwriting input system. The position detection device comprises a resonance circuit, a power supply extraction circuit, a logic control unit, a pressure detection circuit and a key detection circuit, wherein the power supply extraction circuit is used for extracting power from the resonance circuit to provide power for the logic control unit, the pressure detection circuit and the key detection circuit; the pressure detection circuit and the key detection circuit are respectively connected with the logic control unit, the pressure detection circuit comprises a pressure sensor and an analog-to-digital converter connected with the pressure sensor, and the analog-to-digital converter is used for converting analog signals of the pressure sensor into digital signals. The handwriting input system comprises the position detection device. Compared with the related art, the position detection device provided by the invention has the advantages of high pressure sensing precision, simple circuit structure and low circuit power consumption.
Description
Technical Field
The present invention relates to the field of computer peripheral input devices, and in particular, to a position detection device and a handwriting input system.
Background
With technological advancement, digital electronic information devices already have track input functions, and the implementation of such functions usually adopts handwriting input. Handwriting input systems as digital electronic information devices are widely used, which can not only input characters by handwriting, but also realize drawing, point control operation and the like.
The handwriting input system in the related art is mainly divided into an electromagnetic type handwriting input system and a capacitive type handwriting input system, and the electromagnetic type handwriting input system generally comprises a digital board and a handwriting pen matched with the digital board, and the handwriting pen in the related art is mainly divided into an active technology and a passive technology, namely, a battery is required to be installed in the handwriting pen and a battery is not required to be installed in the handwriting pen. The handwriting pen of the passive technology has no battery, so that the user can save the trouble of replacing the battery, but the pressure sensing of the common passive technology is not easy to measure, in order to solve the problem, a digital pen technology is developed, namely, a pressure sensor is arranged at the handwriting pen end, and the obtained pressure sensing is sent to a digital board in a digital coding mode. However, as described in CN101174192B, CN1246681 and CN1983149B in the related art, the counter+data parallel-serial conversion and MCU are adopted, and these technologies have problems of low pressure sensing accuracy, complex circuit, and large circuit power consumption.
Therefore, it is necessary to provide a new position detecting device and handwriting input system to solve the above-mentioned problems.
Disclosure of Invention
The position detection device aiming at the related art has the technical problems of low pressure sensing precision, complex circuit, large circuit power consumption and the like. The invention provides a position detection device with high pressure sensing precision, simple circuit and small circuit power consumption.
The utility model provides a position detection device, its includes resonant circuit, power extraction circuit, logic control unit, pressure detection circuit and button detection circuit, wherein:
the power supply extraction circuit is used for extracting power supply from the resonance circuit to provide power supply for the logic control unit, the pressure detection circuit and the key detection circuit;
the pressure detection circuit and the key detection circuit are respectively connected with the logic control unit, the pressure detection circuit comprises a pressure sensor and an analog-to-digital converter connected with the pressure sensor, and the analog-to-digital converter is used for converting analog signals of the pressure sensor into digital signals.
Preferably, the pressure detection circuit further comprises an amplifier and a filter, wherein a non-inverting input end and an inverting input end of the amplifier are respectively connected with the pressure sensor, an output end of the amplifier is connected with the analog-to-digital converter, and the filter is positioned between the analog-to-digital converter and the logic control unit.
Preferably, the amplifier is an amplifier with adjustable gain, and the gain of the amplifier is determined by the resistance value of a first resistor externally connected with the amplifier.
Preferably, the position detecting device further includes a conversion circuit and a third capacitor, one end of the third capacitor is connected with the resonant circuit, the other end of the third capacitor is connected with one end of the conversion circuit, and the other end of the conversion circuit is connected with the logic control unit.
Preferably, the pressure sensor, the amplifier, the analog-to-digital converter, the filter, the logic control unit, and the conversion circuit are integrated on one IC chip.
Preferably, the resonant circuit comprises a first inductor and a first capacitor which are arranged in parallel, and the first inductor is formed by winding a multi-strand wire-wrapped wire on a ferrite core.
Preferably, the power supply extraction circuit comprises a diode and a fourth capacitor, and the sine wave generated by resonance of the first inductor and the first capacitor is rectified by the diode and then charges the fourth capacitor to form a power supply.
Preferably, the position detecting device further comprises a voltage stabilizing circuit, and the power extracted by the power extracting circuit forms a stable power supply through the voltage stabilizing circuit and outputs the stable power supply to each part on the IC chip.
Preferably, the voltage stabilizing circuit comprises an IC power management circuit and a fifth capacitor externally connected to the IC power management circuit.
A handwriting input system comprising a digitizer and a position detection device according to any one of the above.
Compared with the related art, the position detection device provided by the invention adopts the analog-to-digital converter and logic control circuit technology, the circuit structure is simple, high-precision data can be easily and rapidly sampled by using the analog-to-digital converter, and the power consumption is extremely low, so that the pressure sensing precision of the position detection device is improved and the circuit power consumption is reduced.
Drawings
FIG. 1 is a circuit block diagram of a position detecting device provided by the invention;
fig. 2 is a waveform timing chart of the handwriting input system provided by the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Please refer to fig. 1 in combination. The invention provides a handwriting input system, which comprises a digital board and a position detection device 100 matched with the digital board, wherein in the embodiment, the position detection device 100 is a digital pen.
The position detecting device 100 mainly comprises a resonant circuit, an analog-to-digital converter ADC, an amplifier PGA, a pressure sensor, a stylus button, power management, control timing generation, logic control, and the like.
Specifically, the position detecting device 100 includes a resonant circuit, a power extraction circuit, a logic control unit 10, a pressure detecting circuit, and a key detecting circuit. The power supply extraction circuit is used for extracting power from the resonance circuit to provide power supply work for each part, and the pressure detection circuit and the key detection circuit are respectively connected with the logic control unit.
The resonant circuit comprises a first inductor L1 and a first capacitor C1, wherein the first inductor L1 and the first capacitor C1 form a resonant circuit together, and the resonant frequency of the resonant circuit is the same as the frequency of the digital board transmitting signal. The first inductor L1 is formed by winding a plurality of filament-covered wires on a ferrite magnetic core, and is a receiving antenna and a transmitting antenna.
The power supply extraction circuit comprises a diode D1 and a fourth capacitor C4, and sine waves generated by resonance of the first inductor L1 and the first capacitor C1 are rectified by the diode D1 and then charge the fourth capacitor C4 to form a system power supply. Specifically, the fourth capacitor C4 may be a faraday capacitor with a large capacity.
The pressure detection circuit comprises a pressure sensor 20, an amplifier 30, an analog-to-digital converter 40 and a filter 50 which are sequentially connected, wherein the filter 50 is connected with the logic control unit 10. The non-inverting input and the inverting input of the amplifier 30 are respectively connected to the pressure sensor 20, and the output of the amplifier 30 is connected to the analog-to-digital converter 40.
The pressure sensor 20 is configured to detect pressure, and in this embodiment, the maximum sensing pressure of the pressure sensor 20 is 3N, which can meet the requirement of a general handwriting pressure. It will be appreciated that the pressure sensor 20 may be integrated with the analog-to-digital converter 40, or may be external, so that the pressure sensor 20 may be easily configured when external, and may be easily configured for different types of sensors.
Specifically, in the present embodiment, the pressure sensor 20, the amplifier 30, the analog-to-digital converter 40, the filter 50, and the logic control unit 10 are integrated on one IC chip.
The amplifier 30 is an amplifier with adjustable gain, and the gain of the amplifier 30 is determined by the resistance value of the external first resistor R1.
The analog-to-digital converter 40 is used to convert the analog signal of the pressure sensor 20 into a digital signal. In this embodiment, the analog-to-digital converter 40 is designed to be 13bit (or 14 bit), which can satisfy the 8192 level voltage sense currently popular.
The key detection circuit comprises a switch K1 and a switch K2, the switch K1 and the switch K2 are two key switches on the digital pen, and key information (switch on or switch off state) is encoded into 1 st and 2 nd bits or the last two bits of output serial data.
The position detecting device 100 further includes a voltage stabilizing circuit, a converting circuit 60, and a third capacitor C3, where the third capacitor C3 is connected to the resonant circuit, the converting circuit is connected to the logic control unit 10 and the third capacitor C3, and the voltage stabilizing circuit is connected to the power supply extraction circuit. Specifically, one end of the third capacitor C3 is connected to the resonant circuit, the other end is connected to one end of the conversion circuit 60, and the other end of the conversion circuit 60 is connected to the logic control unit 10. The transfer circuit 60 is integrated with the logic control unit 10, the filter 50, the analog-to-digital converter 40, the amplifier 30, and the pressure sensor 20 on the same IC chip.
The power supply extracted by the power supply extraction circuit forms a stable power supply through the voltage stabilizing circuit and then outputs the stable power supply to each part on the IC chip. The voltage stabilizing circuit comprises an IC power management circuit 70 and a fifth capacitor C5 externally connected to the IC power management circuit. The power supply voltage extracted by the power supply extraction circuit is relatively high and unstable, the power supply voltage to be sent to the IC power management circuit inside the IC chip is converted into stable 1.8V, and the fifth capacitor C5 is an external internal power supply filter capacitor.
Generation of control timing: the sine wave signals received by the first inductor L1 and the first capacitor C1 resonant circuit are coupled to the conversion circuit 60 inside the IC chip through the third capacitor C3, and the conversion circuit 60 filters out the fundamental wave to obtain an envelope signal with lower frequency, and the envelope signal is used as a synchronization signal for the internal operation of the IC chip.
Logic control: the logic control circuit 10 is controlled to synchronize with a control timing sequence, and controls the analog-to-digital converter 40 to sample the pressure sensing data, convert the pressure sensing data in parallel and serial, combine the pressure sensing data with the key information and send the data.
Please refer to fig. 2 in combination. The handwriting input system has the working principle that: the digitizer transmits the signal as a waveform in fig. 2, the first inductor L1 and the first capacitor C1 resonant circuit generate a waveform as B in fig. 2, and a fundamental wave (a portion with a fast pulse width in the front of the waveform A, B) of about 1ms is continuously transmitted in each pressure sensing transmission period, which is used for charging the fourth capacitor C4 and completing analog-to-digital conversion of the pressure sensing signal. When the digital pen is charged to 1.8V by the power supply of the digital pen through wireless power supply, the IC chip part enters into an operating state, a synchronous signal generated by control time sequence is like a C waveform in fig. 2, the analog-digital converter 40 completes analog-digital conversion of pressure sensing data in a front wide pulse part, and each narrow pulse falling edge sends out one bit data in a rear narrow pulse part, wherein data transmission is completed by controlling whether the second capacitor C2 is grounded during transmission. When the second capacitor C2 is grounded, the second capacitor C2 is integrated into a resonant circuit, and the resonant frequency is changed, so that the resonant signal cannot be received due to the fact that the frequency is inconsistent with the bandpass frequency of the digital board receiving circuit, and the information can be defined as binary information. The waveform of example data 1101101011001010 containing key information and pressure-sensitive data is as the D waveform in fig. 2. As can be seen from D, when the data is 1, the logic control unit 10 outputs a high resistance, the second capacitor C2 is not connected to the resonant circuit, and a free oscillation waveform with a longer duration is generated in the first capacitor C1 resonant circuit of the first inductor L1 after the signal transmission is finished; when the data is 0, the logic control unit 10 outputs a short circuit to ground, the second capacitor C2 is connected to the resonant circuit, the loss is increased, and a free oscillation waveform with a shorter duration is generated in the resonant circuit of the first capacitor C1 after the transmission signal is ended.
Compared with the related art, the position detection device provided by the invention adopts the analog-to-digital converter and logic control circuit technology, the circuit structure is simple, high-precision data can be easily and rapidly sampled by using the analog-to-digital converter, and the power consumption is extremely low, so that the pressure sensing precision of the position detection device is improved and the circuit power consumption is reduced.
The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the invention, and all equivalent structures or equivalent processes or direct or indirect application in other related technical fields are included in the scope of the present invention.
Claims (6)
1. The utility model provides a position detection device which characterized in that includes resonant circuit, power extraction circuit, logic control unit, pressure detection circuit and button detection circuit, wherein:
the power supply extraction circuit is used for extracting power supply from the resonance circuit to provide power supply for the logic control unit, the pressure detection circuit and the key detection circuit;
the pressure detection circuit and the key detection circuit are respectively connected with the logic control unit, the pressure detection circuit comprises a pressure sensor and an analog-to-digital converter connected with the pressure sensor, and the analog-to-digital converter is used for converting an analog signal of the pressure sensor into a digital signal;
the position detection device further comprises a conversion circuit and a third capacitor, one end of the third capacitor is connected with the resonant circuit, the other end of the third capacitor is connected with one end of the conversion circuit, and the other end of the conversion circuit is connected with the logic control unit;
the pressure detection circuit further comprises an amplifier and a filter, wherein a non-inverting input end and an inverting input end of the amplifier are respectively connected with the pressure sensor, an output end of the amplifier is connected with the analog-to-digital converter, and the filter is positioned between the analog-to-digital converter and the logic control unit;
the pressure sensor, the amplifier, the analog-to-digital converter, the filter, the logic control unit and the conversion circuit are integrated on one IC chip;
the resonant circuit comprises a first inductor and a first capacitor which are arranged in parallel, wherein the first inductor is formed by winding a plurality of strands of wire covered wires on a ferrite magnetic core, sine wave signals received by the first inductor and the first capacitor on the resonant circuit are coupled to the conversion circuit through a third capacitor, fundamental waves are filtered out by the conversion circuit, an envelope signal is obtained, and the envelope signal is a synchronous signal running inside the IC chip.
2. The position detecting apparatus according to claim 1, wherein the amplifier is an amplifier with adjustable gain, and the gain of the amplifier is determined by a resistance value of a first resistor externally connected to the amplifier.
3. The position detecting device according to claim 1, wherein the power supply extraction circuit includes a diode and a fourth capacitor, and the sine wave generated by resonance between the first inductor and the first capacitor is rectified by the diode and then charges the fourth capacitor to form a power supply.
4. The position detecting apparatus according to claim 3, further comprising a voltage stabilizing circuit, wherein the power extracted by the power extracting circuit forms a stabilized power supply through the voltage stabilizing circuit and outputs the stabilized power supply to each part on the IC chip.
5. The position detecting device as claimed in claim 4, wherein the voltage stabilizing circuit includes an IC power management circuit and a fifth capacitor connected externally to the IC power management circuit.
6. A handwriting input system, comprising a digitizer and a position detection device according to any one of claims 1-5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910920770.0A CN110633025B (en) | 2019-09-26 | 2019-09-26 | Position detection device and handwriting input system |
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| CN201910920770.0A CN110633025B (en) | 2019-09-26 | 2019-09-26 | Position detection device and handwriting input system |
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| CN110633025A CN110633025A (en) | 2019-12-31 |
| CN110633025B true CN110633025B (en) | 2023-07-28 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1413975A1 (en) * | 2002-10-25 | 2004-04-28 | Aiptek International Inc. | Device and method for an electromagnetic digitizer tablet |
| CN103207711A (en) * | 2012-01-13 | 2013-07-17 | 深圳市汇春科技有限公司 | Self-capacitance touch detection circuit and method |
| CN103677337A (en) * | 2012-09-26 | 2014-03-26 | 株式会社和冠 | Position pointer and electronic ink cartridge |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170005286A (en) * | 2015-07-02 | 2017-01-12 | 삼성전자주식회사 | Touch processor circuit and touch screen system performing digital-to-analog conversion of two steps |
| CN107463288B (en) * | 2017-05-26 | 2021-01-26 | 深圳市合众力拓科技有限公司 | Digital input system and implementation method |
| CN109710094A (en) * | 2019-01-16 | 2019-05-03 | 深圳市绘王动漫科技有限公司 | Position detecting system and electronic handwriting pen |
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- 2019-09-26 CN CN201910920770.0A patent/CN110633025B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP1413975A1 (en) * | 2002-10-25 | 2004-04-28 | Aiptek International Inc. | Device and method for an electromagnetic digitizer tablet |
| CN103207711A (en) * | 2012-01-13 | 2013-07-17 | 深圳市汇春科技有限公司 | Self-capacitance touch detection circuit and method |
| CN103677337A (en) * | 2012-09-26 | 2014-03-26 | 株式会社和冠 | Position pointer and electronic ink cartridge |
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Address after: 518108 1st Floor, Building 1, Huiwang Science and Technology Park, Shiyan Street, Tangtou Community, Shiyan Street, Baoan District, Shenzhen, Guangdong Province Patentee after: Shenzhen Huewang Trend Technology Co.,Ltd. Address before: 518103 building 28, area 4, Huaide Cuigang Industrial Park, Fuyong street, Bao'an District, Shenzhen City, Guangdong Province Patentee before: SHENZHEN HUION ANIMATION TECHNOLOGY Co.,Ltd. |