CN1206886A - Digital boards using wireless indicator devices - Google Patents

Abstract

The invention relates to a digital board using a wireless pointer device, which comprises a sensing grid capable of emitting or sensing an intermittent alternating current signal, a movable pointer device and a movable pointer device, wherein the movable pointer device is internally provided with a regulating circuit and can receive the alternating current signal or emit received energy, so that the sensing grid can receive a sensing signal, the position of a pointer device, usually a pen, in the grid formed by a specific wire can be converted into a digital message, and meanwhile, the operating state on the pen is transmitted to the sensed digital board.

Description

Digital boards using wireless indicator devices

The present invention relates to a digital board using a wireless indicator device, in particular to a digital board using a passive wireless indicating device, and the wireless indicating device does not need to use a battery in the digital board using a wireless indicating device.

Referring to the traditional production methods in the past, a digital board that usually uses electromagnetic induction will place a coil on the indicator device, and add a capacitor to form a tuning circuit. In an active indicator device, there will be a battery to supply the tuning circuit to generate an AC signal, which can be transmitted through the coil, and there is a set of parallel sensing wires in the digital board below it, which can receive and sense the signal. The precise location of the indicator device.

Taking the No. 5247138 patent as an example, it has a logic circuit on the pen, which can encode the switch state on the pen into a 9-digit number. There is also a control circuit, which can control the aforementioned tuning circuit to temporarily stop transmitting AC signals. Through this circuit, a data modulation action can be performed. For example, "1" will continue to transmit for a fixed time, "0" "Then launch for half a fixed time and stop launching for half a fixed time. In this way, the above-mentioned 9-digit numbers can be modulated and transmitted in sequence, and the digital board below it can receive the signal and demodulate it, then decode and convert it into a value representing the switch state, and then make the value Relative processing.

In the traditional production method in the past, if a passive indicator device is used, a coil is also placed in it, and a capacitor is added to form a tuning circuit, but no battery is placed in it. The first group of parallel wires is placed in the digital board and emits an AC signal. After the tuning circuit in the indicator device generates harmonic resonance with it, the energy generated by it can be emitted again, and the digital board below it is placed again. A second group of induction wires parallel but perpendicular to the emission wire is provided, which can receive and sense the signal emitted by the tuning circuit in the indicator device to know the precise position of the indicator device, because the second group of parallel wires is connected to the first A group of parallel wires is arranged in parallel, so the AC signal emitted by the first group of parallel wires will not be received.

In U.S. Patent No. 5,220,324, in the passive indicator device, a resistor and a capacitor are connected in series. On the capacitance of the tuning circuit, the aforementioned resistance-capacitance combined circuit is connected in parallel. In addition, there is a set of switches, which can choose to connect some specific resistors in parallel with the aforementioned resistors to change the resistance value in the line. In this way, when the tuning circuit receives an AC signal, the resonant frequency will be changed due to the change of the resistance value, and the phase will change when it is transmitted again. Therefore, on the digital board, a phase detection circuit can be used to know the phase difference between the transmitted AC signal and the received AC signal. The phase difference represents how many resistors are connected in parallel, that is, how many switches are pressed by the user.

Taking a comprehensive view of the above multiple methods, for the No. 5247138 patent, it has a number of disadvantages:

1. There must be a battery in the indicator device to operate. Such a weight is bound to be heavy, and there is a limit to the service life.

2. There must be a more complex modulation coding circuit, especially when the switch input is an analog signal, such as the pressure sensor of the pen tip, there must be an analog/digital conversion circuit on it, so that the battery power consumption will be higher and the lifespan will be higher. will decrease further.

3. Because the time and speed of data transmission on the indicator device cannot be synchronized with the scanning rate of the digital board, when the digital board is scanning the sensing signal, the transmitting signal will be turned off for a short period of time from time to time. As a result, the received signal is unstable, and of course the obtained position of the indicator device will also be unstable.

Taking the No. 5247138 patent as an example, it also has a shortcoming - usually a metal plate is placed under the sensing surface of the digital board to shield some external noise interference. However, when the indicator device is used on the digital board, it will also approach the metal plate, but once the coil is close to the metal plate, its inductance value will change, so even if the switch is not pressed, as long as it is close to the metal plate, The phase of the received signal will change, and it will change with the distance. Although it is also mentioned in the patent that it can be calibrated according to the strength of the received induction signal according to a calibration table, but in actual production, the material of the metal sheet, the material of the coil and the tightness of the winding all have a great influence, and must be mutually Matching is required to conform to the calibration table of the original design. Therefore, there will be many variable factors during production, and multiple correction actions will be required during production, so the defective rate will be high.

The object of the present invention is to provide a digital panel using a wireless indicator device, which does not need to use a battery in the wireless indicator device.

The present invention uses a digital board of a wireless indicator device, which includes: a sensing device with a sensing grid on it, which can emit or sense an intermittent AC signal, and can determine the presence of the aforementioned wireless activity indicator on the sensing grid The position on the grid; and a movable indicator, which has a tuning circuit, which can receive the AC signal transmitted on the aforementioned sensing grid, and the received energy can be re-emitted, so that the sensing grid can be re-transmitted. Receiving a specific induction signal, the activity indicator contains a timing device inside, which starts timing after receiving the aforementioned AC signal, and generates a control signal output after an adjustable time; the activity indicator The device includes a control switch device, which can turn on the switch after receiving the control signal sent by the timing device, and then stop the aforementioned tuning circuit from transmitting signals; wherein the movable indicator device includes a group of key switch devices, the device is It is composed of one or more switches. According to the state of each switch, the counting time length of the timer can be adjusted; the sensing device includes: a set of emitting wires arranged in parallel, which can be used to emit a specific or multiple frequencies AC signal; a set of receiving parallel conductors, which overlap with the above-mentioned first group of parallel conductors at right angles to each other, can receive and sense the frequency emitted by the aforementioned movable indicator; the first multiplex selection device can be used from the above Select any wire in the transmitting parallel wire group to perform the above-mentioned action of transmitting signals; the second multiplex selection device can select any wire from the above-mentioned receiving parallel wire group, and it can select any wire from the above-mentioned receiving parallel wire group. A wire to do the aforementioned action of receiving the sensing signal; a signal processing circuit that can process the aforementioned sensing signal and convert it into a specific value; a timer that can receive the aforementioned sensing signal and count the sensing The duration of the signal; and an operation and control unit, which can be used to control the aforementioned multiplexing selection device to complete a scanning process, and receive the specific value of the aforementioned conversion, and perform calculations to obtain the position of the aforementioned active indicator, and Receive the output of the aforementioned timer, and calculate the usage status of the specific device on the activity indicator; it can further include a group of analog sensing devices, which are composed of one or more sensors. Applying pressure or changing environmental conditions can change its own physical characteristics such as resistance value, capacitance or inductance value, and then change the counting time length of the aforementioned timer.

In order to enable a further understanding of the features and technical content of the present invention, please refer to the following drawings and detailed descriptions of the present invention. However, the accompanying drawings are only for reference and description, and are not intended to limit the present invention, wherein:

Figure 1 is an implementation of a digital pad using a wireless passive pointer pen.

FIG. 2 is a simplified diagram of FIG. 1, which is used to illustrate the transmission and reception of AC signals by the wire set.

FIG. 3A is an example of the operation of a digital tablet using a wireless passive pointing stylus.

FIG. 3B shows the situation of the coil of the pointer pen on the wire grid in FIG. 1 and the situation of the AC signal strength induced by each wire.

FIG. 4 is a diagram showing the relationship between signals generated when using the present invention.

FIG. 5 is a block diagram of a wireless pointer device.

FIG. 6 and FIG. 7 are diagrams showing the relationship between signals generated when using the present invention.

Fig. 8 is a circuit diagram of the present invention.

FIG. 9 is another implementation circuit of the wireless pointer pen in the present invention.

FIG. 10 is another implementation circuit of the wireless pointer pen in the present invention.

Shown in Fig. 1 is the implementation mode and working situation of a digital board with a wireless passive pointer pen. On the sensing surface of the digital board 20, there are two sets of wires arranged in parallel at right angles to overlap each other to form an induction network 21, and two sets of multiplexers 22, 23 are respectively connected to the aforementioned two sets of wires. Among the two groups of wires, only one wire can be selected at the same time, which is used for transmitting or receiving signals. In addition, there are two sets of switches 221, 231, which are respectively used to switch the aforementioned two sets of parallel wires, whether to transmit signals or to receive signals. The actions of the two groups of wires arranged in parallel are opposite, one group is for transmitting signals, and the other group is for receiving signals. In addition, there is a transmitting signal generating circuit 24 to generate an intermittent predetermined frequency (intermittent predetermined frequency) AC signal, which is connected to the aforementioned wire group through the multiplexers 22 and 23 for transmission. The aforementioned specific frequency may be a single fixed frequency or multiple composite frequencies.

Because in a wire group, we will select a certain wire to be adjacent to the wireless indicator device 10 through the multiplexer 22, 23, and can induce mutual induction to generate resonance, so when explaining the circuit here, we will use the wire The group is simplified to a single wire view, as shown in Figure 2. After the above-mentioned AC signal of a specific frequency is emitted through the first wire 232, because the second wire 222 and the first wire 232 are arranged vertically to each other, there will be no mutual induction between the two wires. The tuning circuit 11 in the wireless indicator device 10 can generate mutual inductance with the signal emitted by the first wire 232, and the second wire 222 and the coil in the tuning circuit 11 in the wireless indicator device can generate a second inductance. Mutual induction.

What is shown in FIG. 3A is a working situation of a passive pointer pen 10 using wireless on a digital board 20 .

What is shown in FIG. 3B is the situation of the aforementioned tuning circuit 11 inside the indicator pen 10 on the wire network 20, and each wire is formed by combining at least one outgoing wire and at least one incoming wire. If the signal sensed by each wire is scanned sequentially on the network, it can be found that the wires (Ln-1 and Ln) closer to the center of the tuning line have stronger signals sensed.

Looking back at Fig. 1, the induction AC signal generated by the aforementioned second wire group 222 will be input into a signal amplifier circuit (Signal amplifier) 30, and its output will then be input into a rectifier and filter circuit (rectifier and filter circuit) 40. A voltage corresponding to the amplitude of the induced AC signal is obtained, and the voltage is then input into an analog/digital conversion circuit 50 to obtain a value representing the amplitude of the induced AC signal. In addition, there is a micro-processing unit 60 whose responsibility is to sequentially select each wire to transmit a signal to the aforementioned first wire group 231 through a control logic circuit 70, and also to transmit signals in the second wire group. Step 222 selects each wire in order to sense the signal, and obtains the amplitude of each sensed signal, and finds the one with the largest amplitude among them, which means that the wireless indicator device 10 is near the wire. If you go further to obtain the signal amplitudes on several wires before and after the position, you can obtain a matching multi-time mathematical function based on the obtained several signal amplitude values, and then obtain the Y of the mathematical function The X coordinate at the maximum value of the coordinate is the position of the peak point, which is the position of the wireless indicator device, and the obtained coordinate value is sent to the host computer through the RS232 interface 80, as shown in Figure 3 .

In the aforementioned actions, please refer to FIG. 4 for the signals during the process. The signal (Sig) A is a basic scanning cycle frequency, which is used to control a control logic circuit 70, and then through the multiplexers 22, 23, to select each of the aforementioned second wire groups 222 in sequence. Conductor, for the action of receiving signals. The second signal B is the transmitting signal generating circuit 24 , which generates an intermittent AC signal synchronous with the scanning period, that is, the signal transmitted by the aforementioned first wire group 232 . The signal C is a signal generated by the tuning circuit 11 on the indicator device 10 resonating with the aforementioned signal B. Signal D is the signal induced by the second resonance between each wire on the second wire group 222 and the tuning circuit 11 on the indicator device 10. From this signal, we can see the amplitude of the signal, which is related to the position of the wire. Correspondingly, the wire adjacent to the indicator device 10 will sense the largest signal amplitude. Signal E and signal F are signal amplitude strengths obtained after signal D is amplified, rectified and filtered. This signal can be input into the analog/digital conversion circuit 50 , and a smoother section of the signal is converted into a numerical value, which is then processed by the micro-processing unit 60 to obtain the precise position of the indicator device 10 .

Through the above steps, we can obtain the position of the wireless indicator device 10 on the sensing grid 20, but we still need to further know the state of a group of switches on the wireless indicator device 10, or the position of the nib on the wireless pen 10. The intensity of pressure sensed. Please refer to FIG. 5, which is a block diagram of a wireless indicator device 10, which is mainly the middle tuning circuit 11. When it interacts with the aforementioned wire for transmitting signals, the received energy can be converted through the rectification and filtering circuit 12. It forms a DC voltage VCC and stores it on the capacitor C to supply the power required by other lines in the line. In addition, there is a timer 13 with a variable time, which can generate a pulse after a delay of an adjustable time after receiving a trigger signal. The length of the delay time can be determined according to the state of the key switch 131 being pressed. In the previous description, we have mentioned that the emission signal is an intermittent signal, and the intermittent frequency is the rate at which the sensing wire is scanned and switched. That is to say, each time a sensing wire is selected, an AC signal will be emitted from the transmitting signal wire, and the transmission will stop after a period of time, and then after a period of time, switch to another wire and start transmitting again Signal, such an action will continue to loop.

Therefore, we can use the starting point of the signal transmission as the trigger signal to trigger the aforementioned timer 13, generate a pulse signal after a period of time, and control an analog switch 15, and switch 15 is short-circuited so that the energy of the tuning circuit 11 is instantaneously Released, and can no longer generate mutual inductance with the wire that transmits the signal, so of course the wire at the inductive receiving end can no longer sense any signal. Using the above-mentioned characteristics, when we sense the receiving wire group, the sensed AC signal received not only changes in the intensity of the amplitude, but also has a change in duration. Therefore, at the induction receiving end, in addition to knowing the position of the indicator device 10 from the amplitude, we can also know the use status of the switch 131 on the indicator device 10 from the length of the duration.

Next, please refer to FIG. 6 , which illustrates the above-mentioned actions. The signal G is the same as the aforementioned signal A, that is, the basic scan cycle frequency, and the signal H is also the same as the aforementioned signal B, that is, an intermittent AC signal that is transmitted synchronously with the scan cycle. The signal I is the induction signal generated by the tuning circuit 11 on the wireless indicator device 10 , what is seen here is the induction signal assumed to be generated naturally, and the analog switch 15 is not used for energy release. The signal J is the DC voltage generated by filtering the induction signal after passing through the rectifier 12 in FIG. 5 , which can be supplied to other parts of the circuit as a power supply voltage. The signal K is a timer 13 that can change the time. After receiving the transmission signal, according to the state of use of the switch 131 on the indicator device 10, it starts to count the time by using the charging characteristics of the resistance and capacitance. When it is charged to a specific critical voltage , a high potential will be generated, as shown by the signal L, and the high potential will trigger and turn on an analog switch 15, and then the energy in the tuning circuit 11 will be released instantly, as shown by the signal M . Since the energy in the tuning circuit 11 has been released, the timer 13 has no input signal, so the timing capacitor starts to discharge until fully discharged. And in its discharging process, when being put into another specific critical voltage, can output a low electric potential, and make timer 13 output return to zero.

Next, please refer to Figure 7. The signal N is the AC signal received by the wire at the induction receiving end. Its D' point is that after the counting time is up, the energy in the tuning circuit 11 is released and can no longer be received. signal. The signal O and the signal P are signals received by the induction after passing through the rectification and filtering circuit 40 , and then compared with a threshold voltage of a specific level through a comparator to obtain a signal such as the signal Q. The signal Q is used to control a counter to count at a specific frequency, and the obtained value represents the status of the switch 15 on the wireless indicator device 10 or the pressure status on the pen tip of the wireless pen 10 .

FIG. 8 is an implementation circuit of a wireless indicator pen 10 in the present invention, wherein VR is a device that can accept pressure to change the resistance value. When pressure is applied, the resistance will decrease as the pressure increases. SWr1-SWrn is composed of several switches, and the total resistance value becomes smaller when more switches are pressed. SWc1-SWcn is also composed of several switches, and the more switches are pressed, the greater the total capacitance will be. In this way, the charging time of the timer 13 can be changed according to the pressure and the state of the switch, and the analog switch 15 is implemented by a transistor.

Fig. 9 is then among the present invention, another kind of action circuit of a wireless indicator pen 10, and its circuit is roughly all similar with Fig. 8, just timer 13 changes digital timer into. OSC is a generator of a specific frequency, and the specific frequency will be input into a counter 132 that can be divided by N and can be counted up/down. When the tuning circuit 11 receives the signal, it will generate a high potential to the counter 132, so that the counter 132 starts to count up, and Qx to Qx+m are respective overflow outputs that divide the aforementioned specific frequency by N, and are high potential outputs. For example, Qx is divided by 256, Qx+1 is divided by 266, Qx+2 is divided by 276...and so on. In this way, if the user does not press the button, the OR gate will output a high potential after the longest Qx+m is generated, so that the analog switch 15 is turned on, and then the energy of the tuning circuit 11 is released. After the energy in the tuning circuit 11 is released, a low potential is generated for the counter 132, so that the counter 132 starts counting down, stops until it returns to zero, and starts to wait for the next cycle. In this way, if the user presses a button, the analog switch 15 will be turned on ahead of time, and a function similar to that of the circuit in FIG. 8 can be produced.

Fig. 10 is another implementation circuit of the wireless indicator pen in the present invention. This circuit is to improve the circuit of the foregoing Fig. 9, wherein an RC-controlled oscillator 133 is used to generate a counting frequency, and the oscillation In the circuit, there is a set of external switch groups that can control the total resistance and capacitance, and then control the counting frequency generated by the oscillator 133 . Among them, VR is a device that can change the resistance value by accepting pressure. In FIG. 3A , it shows the working situation of a wireless passive indicator pen 10 in the sensing network 21 .

What is shown in FIG. 3B is the situation of the aforementioned tuning circuit 11 inside the indicator pen 10 on the wire grid 20, and each wire is formed by combining at least one outgoing wire and at least one incoming wire. If the signal sensed by each wire is scanned sequentially on the grid, it can be found that the wires (Ln-1 and Ln) closer to the center of the tuning line have stronger signals sensed. Can also affect the sum resistor value. The subsequent counter 134 is fixedly divided by N to generate an overflow output, which is at a high potential and turns on the analog switch 15 . In addition, when the tuning circuit 11 receives the signal, it will generate a high potential to the counter 134, so that the counter 134 leaves the reset state, and then starts counting according to the aforementioned counting frequency, until the overflow signal is generated, the analog switch 15 is turned on, and the The energy of the tuned line 11 is released. When the energy of the tuning circuit 11 is released, the counter 134 will get a low potential, so that the counter 134 is always in the reset state, and the overflow output is cleared, and the waiting state is maintained until the next cycle starts again. In this way, when the user presses the button or changes the pressure of the pen tip, he can also control when to release the energy of the tuning circuit 11 to achieve the same function as the circuit shown in FIG. 8 .

The specific embodiments above are used to describe the purpose, features and effects of the present invention in detail. For those who are familiar with this type of technology, according to the above description, some changes and modifications may be made to the specific embodiments without departing from Out of the spirit category of the present invention.

Claims (5)

1. A digital board using a wireless indicator device, characterized in that its composition comprises: A sensing device with a sensing grid on it, which can emit or sense an intermittent AC signal, and can determine the position of the aforementioned wireless activity indicator on the sensing grid; and A movable indicator, which has a tuning circuit, can receive the AC signal transmitted on the aforementioned sensing grid, and the received energy can be re-emitted, so that a specific signal can be sensed on the sensing grid. Induction signal, the activity indicator contains a timing device inside, which starts timing after receiving the aforementioned AC signal, and generates a control signal output after an adjustable time. 2. The digital board using the wireless indicator device according to claim 1, wherein the movable indicator includes a control switch device, which can make the switch conduct after receiving the control signal sent by the timing device, Further, the aforementioned tuning circuit stops transmitting signals. 3. The digital board using the wireless indicator device according to claim 1, wherein the movable indicator device includes a group of key switch devices, the device is composed of one or more switches, according to each switch state, the counting time length of the timer can be adjusted. 4. The digital board using the wireless indicator device according to claim 1, wherein the sensing device comprises: A set of transmitting wires arranged in parallel, which can be used to transmit AC signals of a specific or multiple frequencies; A group of receiving wires arranged in parallel, which are placed at right angles to the first group of parallel wires and overlapped with each other, can receive and sense the frequency emitted by the aforementioned movable indicator; The first multiplexing selection device, which can select any one wire from the above-mentioned transmitting parallel wire group, and perform the above-mentioned action of transmitting signals; The second multiplexing selection device, which can select any one wire from the above-mentioned receiving parallel wire group, and perform the aforementioned action of receiving the induction signal; A signal processing circuit, which can process the aforementioned induction signal and convert it into a specific value; A timer, which can receive the sensing signal and count the duration of the sensing signal; and An operation and control unit, which can be used to control the aforementioned multiplexing selection device to complete a scanning procedure, and receive the specific value of the aforementioned conversion, perform calculations to obtain the position of the aforementioned activity indicator, and receive the aforementioned timer value Output, which is calculated to know the usage status of the specific device on the activity indicator. 5. The digital board using a wireless indicator device according to claim 1, characterized in that, it can further include a group of analog sensing devices, which are composed of one or more sensors, which can receive external pressure Or when the environmental conditions change, the physical characteristics such as resistance value, capacitance or inductance value can be changed, and then the counting time length of the aforementioned timer can be changed.

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