CN104077004B - Motion detection method and pointer - Google Patents
Motion detection method and pointer Download PDFInfo
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- CN104077004B CN104077004B CN201310122732.3A CN201310122732A CN104077004B CN 104077004 B CN104077004 B CN 104077004B CN 201310122732 A CN201310122732 A CN 201310122732A CN 104077004 B CN104077004 B CN 104077004B
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Abstract
The invention relates to a motion detection method and a pointer of a digitizer, a point reader, a hand mark and the like, which realize the simultaneous incoherent detection of the Q value and the frequency of a pointer resonance circuit.
Description
The technical field is as follows:
the invention relates to a motion detection method and a pointer for a digital board, a point-reading machine, a hand mark and the like.
Background art:
for simplicity of description, a tablet, a pen in a point-and-read machine, a mouse (a mouse-like position indicator different from a general mouse), and the like are called a pointer; the position (including x, y and z axes), posture (including included angle with x, y and z axes and pointer spin angle), pressure (including contact force between the pen tip and the panel and grip force of fingers holding the pointer), key state and the like of the pointer respectively correspond to different actions of the handheld pen, and the detected quantities related to the characteristics of the pointer and detected by an electromagnetic coupling mode are collectively called action variables, the detection of these variables is called action variable detection, and the device for detecting action variables associated with the pointer is called action detection device, and the action detection device also includes antenna matrix and action detection circuit, the antenna matrix is formed from several sub-antennas, and the pointer and action detection device are called action sensor together, and the action sensor can detect all the above-mentioned action variables, also can detect one or several of them, or has no other action variables mentioned above.
The sensors have a common characteristic that the motion of the pointer is detected by means of electromagnetic coupling of the pointer and the antenna matrix, and are practically used in the technologies of patents 200420003299.8 and 200910075485x, wherein 200420003299.8 is a motion detection technology in which the pointer has a battery, the pointer has only an electromagnetic emission state and no electromagnetic receiving state, and 200910075485x is a motion detection technology in which the pointer has both an electromagnetic emission state and an electromagnetic receiving state. The principle is that the sub-antennas to be detected are sequentially accessed and sampled in a scanning mode, and the action variable is calculated according to the sampled data.
The patent "CN 88104538" discloses a closest technical solution to the present invention, and a detection period includes a position detection device of a transmission period and a reception period, and the time sequence of one detection period is shown in fig. 7.
The device detects the motion of the pointer in a magnetic coupling mode, wherein one scheme is to detect the motion of the hand by detecting the change of the resonant frequency in the pointer, for example, a pressure sensor is used for converting pressure into the change of resonant capacitance so as to influence the resonant frequency, for example, a key is used for converting the motion of a key into the change of the resonant capacitance so as to influence the resonant frequency, and then the motion is distinguished according to the change of the resonant frequency. However, when multiple variables to be examined are sometimes required, interference between the variables can affect the overall system function.
The invention content is as follows:
in order to solve the above problems, the present invention aims to:
implementing a motion sensor;
detecting the frequency of a resonant circuit
Detecting the Q value of the resonant circuit;
detecting pressure;
detecting a key;
distinguishing different electromagnetic pens;
the electromagnetic pen is used for communicating with the detection device;
the detection speed is improved.
In order to realize the purpose of the invention, the following technical scheme is configured:
a motion detection method comprises configuring a pointer and a sensor; an LC resonance circuit is configured in the pointer, and the LC resonance circuit is configured with variable impedance; the sensor is configured with an antenna coil; the antenna coil is magnetically coupled with the LC resonant circuit, and one detection period comprises a transmitting period and a receiving period; the receiving period is used for receiving the signal of the LC resonant circuit by an antenna coil of the sensor; comprises calculating the physical quantity of motion detection according to the sampling data of the receiving period;
the receiving period comprises a first receiving period and a second receiving period;
ceasing transmission during the receive period;
the starting time or the ending time of the first receiving period is different from that of the second receiving period or the starting time and the ending time are different;
is further configured to
The method comprises the steps of calculating the sampling amplitude of a first receiving period, and calculating the sampling amplitude of a second receiving period;
the sampled amplitude value of the first reception period and the sampled amplitude value of the second reception period are used as raw data for calculating the detection of the motion.
Is further configured to
Comprising the step of calculating a ratio of the sampled amplitude of the first receive period to the sampled amplitude of the second receive period.
Is further configured to
The identity of the pointer is specified in accordance with a ratio of the sampled magnitude of the first receive cycle to the sampled magnitude of the second receive cycle falling within a different specified range.
Can be configured into
The data transmission bit is specified according to a ratio of the sampling amplitude of the first reception period and the sampling amplitude of the second reception period falling within a different specified range.
Can be configured into
Solving a Q value according to the ratio of the detection amplitude of the first receiving period to the detection amplitude of the second receiving period and the time difference of sampling;
using different said Q values to transfer more than one bit of data in a detection period.
Can be configured into
Comprising the step of calculating a ratio of the sampled amplitude of the first receive period to the sampled amplitude of the second receive period.
Solving a Q value according to the ratio of the detection amplitude of the first receiving period to the detection amplitude of the second receiving period and the time difference of sampling;
using different values of said Q0, Q1, Q2, Q3 to convey 2 bits of data.
Can be configured into
The method comprises the steps of calculating the sampling phase of a first receiving period and calculating the sampling phase of a second receiving period;
the sampling phase of the first reception cycle and the sampling phase of the second reception cycle are used as raw data detected by the calculation operation.
Can be configured into
Comprising the step of calculating the difference between the sampling phase of the first reception period and the sampling phase of the second reception period.
Can be configured into
The first receiving period in different detection periods is compared with the first receiving period, and the second receiving period in different detection periods is compared with the second receiving period, and the starting time or the ending time or both the starting time and the ending time are different.
Can be configured into
Including a third receive period.
Can be configured into
The pointer configuration variable resistance changes the Q value of the LC resonant circuit.
Can be configured into
The variable resistor is connected with the inductor in series and then connected into the LC resonance circuit.
Can be configured into
The variable resistor is connected with the capacitor in series and then connected into the LC resonance circuit.
Can be configured into
The variable resistor is connected to a middle tap of an inductor in the LC resonance circuit.
Can be configured into
The variable resistor is connected to a middle tap of a capacitor in the LC resonance circuit.
Can be configured into
The pointer configuration variable capacitance changes the resonant frequency of the LC resonant circuit.
Can be configured into
The pointer is provided with a variable resistor to change the Q value of the LC resonance circuit, and is provided with a variable capacitor to change the resonance frequency of the LC resonance circuit.
Can be configured into
The pointer configuration inductance loss changes the Q value of the LC resonant circuit.
The inductance coil to be detected is an open inductance coil and can transmit and receive electromagnetic induction for indicating position.
Description of the drawings:
FIG. 1 is a schematic diagram of a pointer of a prior art scheme
FIG. 2 is a schematic diagram of a stylus with a pressure-capacitance sensor tip and a resistive button according to the present invention
FIG. 3 is a schematic diagram of a stylus with a piezo-resistive sensor tip and capacitive buttons according to the present invention
FIG. 4 pointer schematic of the present invention
FIG. 5 is a schematic diagram of the detection circuit
FIG. 6 is a schematic diagram of a signal conditioning circuit
FIG. 7 is a waveform diagram of a detection period of a prior art scheme detection circuit
FIG. 8 is a waveform diagram of a detection cycle of the detection circuit of the present invention
FIG. 9 is a schematic diagram of a resistance series resonant circuit
FIG. 10 is a schematic diagram of a resistance parallel resonant circuit
FIG. 11 is a schematic diagram of a resistor access method
The figures and the reference numbers in the drawings represent the meanings:
r1, R11, R12: equivalent resistance
R2, R21, R22, R23, R24: pressure-resistance sensor
C2: pressure-capacitance sensor
L1, L11, L12, L13, L14: coil to be tested
C1, C3, C11, C12, C13, C14, C15: capacitor with a capacitor element
R3: resistance (RC)
S1: push-button switch
S2: analog switch
S3: transmitting-receiving control analog switch
1; pointer with a movable finger
2: antenna array
21: sub-antenna
22: sub-antenna
41: amplifying circuit
42: filter circuit
43: synchronous detection circuit
44: A/D converter
5: calculating part
PS 1: test point at analog switch S3 control line
P41: test points at the input of the amplifier 41
P42: test point at detector 43 input
P43: test point at output Q term of synchronous detector 43
P44: test point at output I of synchronous detector 43
P11: pointer for testing point at position
P12: pointer for testing point at position
P11-P12: point difference between test points P11 and P12
The specific implementation mode is as follows:
as shown in fig. 1, the passive pointer (an electromagnetic pen) is a schematic diagram, and the pointer is composed of a resonant circuit composed of a coil L1 to be detected and a capacitor C1, wherein R1 is an equivalent resistance of all losses including a conductor resistance loss, a dielectric loss and an emission loss, and a resonant frequency of the resonant circuit is determined by values of L1 and C1; the L1 is an open type inductor, when the changed magnetic line passes through the coil of the inductor L1, voltage can be generated, when the changed current flows through the inductor L1, the inductor L1 can emit electromagnetic signals, when the electromagnetic signals with the same resonant frequency as that of the resonant circuit consisting of the L1 and the C1 are excited, the resonant circuit consisting of the L1 and the C1 in the pointer resonates, and when the excitation signals are cancelled, the attenuation oscillation, namely echo, is kept continuously. C2 is a nib pressure-capacitance sensor, when the pressure increases, the capacitance increases, thus the resonance frequency of the pointer decreases, the frequency change can detect the pressure change of the nib, the key S1 is connected with the capacitance C3, the C3 is larger than the maximum value of the variable capacitance C2, therefore the resonance frequency when the key is pressed is lower than the frequency under any pressure, all can distinguish whether the key is pressed, but the key is difficult to detect the nib pressure correctly in the key pressing process due to the chattering effect of the key, and the key and the nib pressure detection have conflict.
As shown in FIG. 2, the pointer with pressure-capacitance sensor pen tip and resistance key, the key S1 is connected with the resistance R3 to change the Q value of the resonance circuit, and the Q value only has no influence on the frequency when the key is pressed or not pressed, so that the interference between the key and the pen tip pressure detection can be eliminated in principle. Only one key is shown in the figure, although the configuration of multiple keys is not a problem.
As shown in the position pointer with the pressure-resistance sensor pen point and the capacitance key of the figure 3, the key S1 is connected with the capacitance C3 and is used for changing the frequency of the resonance circuit, the frequency value which is influenced by whether the key is pressed or not has no influence on the Q value, and the pen point pressure is changed by the Q value of the resonance circuit, so the interference between the key and the pen point pressure detection can be eliminated in principle.
Referring to fig. 4, which shows a pointer with a pressure-capacitance sensor pen tip and a pressure-resistance sensor key, the change in resistance when the key R2 is pressed changes the Q value of the resonant circuit, and the pressing pressure of the key affects only the Q value and has no effect on the frequency, so that the interference between the key pressure and the pen tip pressure detection can be eliminated in principle. This has the advantage of providing a total of two pressure measurements.
Fig. 5 is a schematic block diagram of a pointer motion detection scheme in an electromagnetic coupling manner, where the entire system includes a pointer and a motion detection device, the motion detection device includes an antenna matrix and a signal conditioning circuit, the antenna matrix includes a plurality of sub-antennas arranged along x-axis and y-axis, the motion detection circuit includes a sub-antenna selection switch, an amplification filter circuit, a synchronous detector, an analog-to-digital converter, a cpu, and an AC signal generator, and the amplification filter circuit, the synchronous detector, and the analog-to-digital converter are referred to as the signal conditioning circuit as a whole.
Fig. 6 shows a signal conditioning circuit for detecting the resonant frequency of the pointer, the conventional circuit structure is substantially the same as the circuit structure of the present invention, except that the waveform control in each component is different, as shown in fig. 7, in one detection period, the signal generator in the conventional method first transmits an electromagnetic signal to the antenna, then stops transmitting to end the transmission period, and then provides a local oscillator signal of one reception period to the synchronous detector (shown by the waveform of the test point P32); as shown in fig. 8, in one detection period of the present invention, after the transmission period from the signal generator to the antenna is completed, the local oscillator signals of the first receiving period and the second receiving period are provided to the synchronous detector, and the ADC samples the synchronous detection data twice respectively at the end of the first receiving period and the end of the second receiving period.
In the following, the Q value detection principle is considered, and since the Q values of the resonant circuits are different, the amplitude attenuation multiples are different within the same time; the different initial amplitude magnitudes in the resonant circuit at constant Q, with the amplitude decay times constant over the same time, are a fundamental property of the resonant circuit. In view of this property, since the amplitudes detected by the synchronous detectors of the first reception period and the second reception period represent the amplitude of oscillation in the oscillation circuit, the Q value can be found using the ratio of the detected amplitude of the first reception period to the detected amplitude of the second reception period, and the time difference of sampling. It is to be noted that the gains of the amplifying circuits in the first receiving period and the second receiving period may be set to different values, and the correct Q value can be calculated as long as the values of the gains are known. In addition, the process of calculating the Q value can be omitted, for example, the amplitude ratio is directly used as raw data corresponding to the pressure, the correct pressure value can be detected through calibration and linear transformation by using the calibration data, and other specified physical quantities can be detected if the pressure-resistance sensor is replaced by other X-resistance sensors.
On the other hand, in the conventional frequency detection method, the phase value of the second receiving period is not used, but the local oscillator of the transmitting period is assumed to be synchronous with the oscillation of the resonant circuit in the pointer at the end of the transmitting period, and the frequency of the resonant circuit in the pointer is directly calculated by using the phase in the receiving period and the frequency of the local oscillator; however, considering that the resonance of the pointer and the transmission waveform in the transmission period need more transmission signal time, when the transmission signal time is shorter, especially when the transmission signal frequency and the resonance frequency of the pointer have deviation, the local oscillator and the pointer resonance often have phase difference, which causes a larger error in frequency detection; the present invention solves this problem by using the frequency of the phase difference calculation for the two receive cycles because the detected phase difference for the two receive cycles is not changed regardless of whether the transmit signal is synchronized with the resonance in the hand at the end of the transmit cycle.
Other embodiments related to the application of Q value detection are considered below after the method for detecting Q value.
If different attenuation resistors are set in different pointers, resulting in different Q values, the identity of the currently operating pointer can be distinguished by detecting the Q value of the pointer, such as specifying whether it is a pencil or an eraser. Of course, other methods may be used to set the Q value, such as using eddy currents to change the loss of the inductor, using capacitors with different losses, etc.
If data is transferred between the pointer and the sensing circuit, different values of Q may be used to transfer more than one bit of data in a sensing cycle. For example, when the detection device needs to receive the data transmitted by the pointer, the detection device sets different Q values Q0, Q1, Q2 and Q3, at the end of the transmission period, the analog switch in the pointer is controlled by the cpu in the pointer, the specified resistor is connected to the resonant circuit in the pointer, and the Q value of the resonant circuit is one of Q0, Q1, Q2 and Q3, respectively, so that the detection device can judge which of 0, 1, 2 and 3 the data transmitted by the pointer is based on the detected Q value and the Q value falls in the vicinity of which of Q0, Q1, Q2 and Q3, thereby realizing 2-bit data transmission, and if more levels are used, more bits can be transmitted at a time.
In this embodiment, a synchronous detector capable of detecting the amplitude and phase of a detected signal simultaneously is used, so as to detect the frequency and Q value simultaneously, if we want to obtain only one of the physical quantities, for example, the Q value can be detected by using the amplitudes of the first receiving period and the second receiving period output by the ordinary detector, and for example, the frequency can be detected by using the phases of the first receiving period and the second receiving period output by the phase detector to calculate the frequency; of course, a common detector and a phase detector can be arranged at the same time to detect the frequency and the Q value at the same time. The common detector comprises a diode detector, a zero-crossing detection detector and the like, and the phase discriminator comprises a phase-locked loop phase discriminator, a pulse phase discriminator and the like.
In addition, in some cases, the time difference between the first receiving period and the second receiving period in different detection periods needs to be controlled, if the receiving time difference is long and the Q value of the pointer resonant circuit is small, the amplitude of the signal in the first receiving period may be too large and the amplitude of the signal in the second receiving period may be too small, even if the programmable amplifier is used to specify that the gain of the second receiving period is maximum, the amplitude of the signal is too small, and then the time difference between the first receiving period and the second receiving period should be reduced; in addition, when detecting the frequency, if the difference between the local oscillator frequency and the pointer resonant frequency is large and the time difference between the first receiving period and the second receiving period is long, the actual phase difference may be larger than 360 degrees, and the synchronous detector can only detect the value of 0-360 degrees, so that an error may be generated, so that a small receiving time difference should be used in this case. More receiving cycles can be set to solve the above problem, multiple groups of amplitude and phase data are sampled in one detection cycle, optimal data are selected according to needs, the Q value and the frequency of the pointer are calculated, and three receiving cycles are preferably used.
In some cases, since the dynamic range of the value of the pressure-resistance sensor is not satisfactory, which is generally reflected in that the equivalent resistance is replaced with the sensor resistance in series as in fig. 9, the access resistance is too large so that the Q value of the resonance circuit is too small to be used in the pointer, and the equivalent resistance is replaced with the sensor resistance in parallel as in fig. 10, the access resistance is too small so that the Q value of the resonance circuit is too small to be used in the pointer; the solution to the problem is to need various connection methods as shown in fig. 11, and their common features are that when it is converted into an equivalent circuit as shown in fig. 9, the actually connected resistance is larger than the equivalent resistance R11, and when it is converted into an equivalent circuit as shown in fig. 10, the actually connected resistance is smaller than the equivalent resistance R12, and these connection methods can easily find a proper configuration by adjusting the related inductance and capacitance values. Such a connection form brings about a side effect that the sensor influences the frequency of the resonance circuit while adjusting the Q value of the resonance circuit, but considering that a change in the Q value has a definite influence on the resonance frequency, which influence can be defined in advance as a Q value frequency error, when there is another sensor in the resonance circuit that changes the frequency, it is possible to first detect the frequency of the resonance circuit and then subtract the true value that characterizes the Q value-frequency error to the sensor; the mutual influence of the Q value sensor and the frequency sensor is separated through calculation.
Note: the embodiments described in the present specification are preferred embodiments, and may be used to describe the objects and means of the invention as a whole, and are not intended to be exhaustive.
Claims (20)
1. A motion detection method comprises configuring a pointer and a sensor; an LC resonance circuit is configured in the pointer, and the LC resonance circuit is configured with variable impedance; the sensor is configured with an antenna coil; the antenna coil is magnetically coupled with the LC resonant circuit, and one detection period comprises a transmitting period and a receiving period; the receiving period is used for receiving the signal of the LC resonant circuit by an antenna coil of the sensor; comprises calculating the physical quantity of motion detection according to the sampling data of the receiving period; the method is characterized in that:
the receiving period comprises a first receiving period and a second receiving period;
ceasing transmission during the receive period;
the first receiving period and the second receiving period have different starting time or ending time or different starting time and ending time.
2. The motion detection method according to claim 1, wherein:
the method comprises the steps of calculating the sampling amplitude of a first receiving period, and calculating the sampling amplitude of a second receiving period;
the sampled amplitude value of the first reception period and the sampled amplitude value of the second reception period are used as raw data for calculating the detection of the motion.
3. The motion detection method according to claim 2, characterized in that:
comprising the step of calculating a ratio of the sampled amplitude of the first receive period to the sampled amplitude of the second receive period.
4. The motion detection method according to claim 3, characterized in that:
the identity of the pointer is specified in accordance with a ratio of the sampled magnitude of the first receive cycle to the sampled magnitude of the second receive cycle falling within a different specified range.
5. The motion detection method according to claim 3, characterized in that:
the data transmission bit is specified according to a ratio of the sampling amplitude of the first reception period and the sampling amplitude of the second reception period falling within a different specified range.
6. The motion detection method according to claim 1, wherein:
comprises the steps of calculating the ratio of the sampling amplitude of the first receiving period to the sampling amplitude of the second receiving period;
solving a Q value according to the ratio of the detection amplitude of the first receiving period to the detection amplitude of the second receiving period and the time difference of sampling;
using different said Q values to transfer more than one bit of data in a detection period.
7. The motion detection method according to claim 1, wherein:
comprises the steps of calculating the ratio of the sampling amplitude of the first receiving period to the sampling amplitude of the second receiving period;
solving a Q value according to the ratio of the detection amplitude of the first receiving period to the detection amplitude of the second receiving period and the time difference of sampling;
using different values of said Q0, Q1, Q2, Q3 to convey 2 bits of data.
8. The motion detection method according to claim 1, wherein:
the method comprises the steps of calculating the sampling phase of a first receiving period and calculating the sampling phase of a second receiving period;
the sampling phase of the first reception cycle and the sampling phase of the second reception cycle are used as raw data detected by the calculation operation.
9. The motion detection method according to claim 8, wherein:
comprising the step of calculating the difference between the sampling phase of the first reception period and the sampling phase of the second reception period.
10. The motion detection method according to claim 1, wherein:
the first receiving period in different detection periods is compared with the first receiving period, and the second receiving period in different detection periods is compared with the second receiving period, and the starting time or the ending time or both the starting time and the ending time are different.
11. The motion detection method according to claim 1, wherein:
including a third receive period.
12. The motion detection method according to claim 1, wherein:
the pointer configuration variable resistance changes the Q value of the LC resonant circuit.
13. The motion detection method according to claim 12, wherein:
the variable resistor is connected with the inductor in series and then connected into the LC resonance circuit.
14. The motion detection method according to claim 12, wherein:
the variable resistor is connected with the capacitor in series and then connected into the LC resonance circuit.
15. The motion detection method according to claim 12, wherein:
the variable resistor is connected to a middle tap of an inductor in the LC resonance circuit.
16. The motion detection method according to claim 12, wherein:
the variable resistor is connected to a middle tap of a capacitor in the LC resonance circuit.
17. The motion detection method according to claim 1, wherein:
the pointer configuration variable capacitance changes the resonant frequency of the LC resonant circuit.
18. The motion detection method according to claim 1, wherein:
the pointer is provided with a variable resistor to change the Q value of the LC resonance circuit, and is provided with a variable capacitor to change the resonance frequency of the LC resonance circuit.
19. The motion detection method according to claim 1, wherein:
the pointer configures a Q value;
the Q value changes the loss profile of the inductor using eddy currents.
20. The motion detection method according to claim 1, wherein:
the pointer configures a Q value;
the Q value uses a capacitance configuration of different losses.
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| CN101174192A (en) * | 2006-10-31 | 2008-05-07 | 株式会社华科姆 | Position-detecting apparatus and position-indicating device |
| CN101685366A (en) * | 2008-09-26 | 2010-03-31 | 汉王科技股份有限公司 | Electromagnetic induction device with multi-touch function |
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| JPH031213A (en) * | 1989-05-29 | 1991-01-07 | Pentel Kk | Information input device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101174192A (en) * | 2006-10-31 | 2008-05-07 | 株式会社华科姆 | Position-detecting apparatus and position-indicating device |
| CN101685366A (en) * | 2008-09-26 | 2010-03-31 | 汉王科技股份有限公司 | Electromagnetic induction device with multi-touch function |
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