CN101957706A

CN101957706A - Electromagnetic handwritten device

Info

Publication number: CN101957706A
Application number: CN 201010298295
Authority: CN
Inventors: 尹航
Original assignee: Hanwang Technology Co Ltd
Current assignee: Hanwang Technology Co Ltd
Priority date: 2010-09-30
Filing date: 2010-09-30
Publication date: 2011-01-26
Anticipated expiration: 2030-09-30
Also published as: CN101957706B

Abstract

The invention provides an electromagnetic handwritten device, comprising an electromagnetic input pen, an electromagnetic plate, a control part, a receiving unit and a transmitting unit. The electromagnetic plate is provided with a receiving coil and a transmitting coil; the receiving unit receives signals from the receiving coil to process and transmits the processed signals to the control part; and the transmitting unit processes the signals output by the control part and transmits the signals to the transmitting coil, wherein the control part transmits a control signal to the transmitting unit according to the strength of the signals received by the receiving unit, and the transmitting unit regulates the power of signals transmitted to the transmitting coil according to the control signal. The invention can reduce the power consumption of the electromagnetic handwritten device when a user carries out the input operation, meet the requirements of a mobile device and reduce the interference on other devices as smaller as possible.

Description

Electromagnetic handwriting equipment

Technical Field

The invention relates to a handwriting device, in particular to an electromagnetic handwriting device.

Background

In the prior art, electromagnetic handwriting devices generally comprise: a stylus pen having an electromagnetic oscillation circuit; a plurality of sets of transmitting coils; a transmission unit for supplying power to the transmission coil and transmitting electromagnetic waves; a plurality of sets of receiving coils arranged perpendicular to the plurality of sets of transmitting coils; and a control unit for controlling the scanning operation of the receiving coil. The control part controls the scanning of the multiple groups of receiving coils and the multiple groups of sending coils so as to determine that the power of the signals sent by the multiple groups of sending coils is constant no matter the size of the received signals when the electromagnetic handwriting equipment works.

However, when the electromagnetic pen approaches or contacts the handwriting board provided with the receiving coil, since the electromagnetic pen is close to the handwriting board and the intensity of the induced electromagnetic wave generated by the electromagnetic pen in the receiving coil is high, the received signal is strong, and therefore, the handwriting pen can be positioned without actually needing the transmitting unit to transmit a strong signal. Therefore, sending unnecessary strong signals at this time causes energy waste, and is not beneficial to reducing the power consumption of the whole device, especially when the electromagnetic handwriting device is applied to a mobile device, the power consumption of the device needs to be reduced as much as possible. In addition, the transmission power of the transmitting unit is constant regardless of the size of the received signal, that is, the radiation to the outside of the whole electromagnetic handwriting system is constant, so that interference to other devices is caused.

Disclosure of Invention

The invention aims to provide an electromagnetic handwriting device with low power consumption and low interference.

The electromagnetic handwriting device of the present invention includes: an electromagnetic input pen; an electromagnetic plate having a receiving coil and a transmitting coil; a control unit; a receiving unit that receives a signal from the receiving coil, processes the signal, and transmits the processed signal to the control unit; and a transmission unit that processes a signal output from the control unit and transmits the signal to the transmission coil, wherein the control unit transmits a control signal to the transmission unit according to the intensity of the signal received by the reception unit, and the transmission unit adjusts the power of the signal transmitted to the transmission coil according to the control signal.

The electromagnetic handwriting equipment of the invention utilizes the control part to adjust the power of the sending unit for supplying power to the sending coil, so that the sending unit sends a signal with low power when the electromagnetic pen is close to or in contact with the electromagnetic plate, and sends electromagnetic waves with high power when the electromagnetic pen is far away from the electromagnetic plate, thereby reducing the power consumption of the electromagnetic handwriting equipment when a user carries out input operation, being suitable for the requirements of mobile equipment, and reducing the interference to other equipment.

Drawings

Fig. 1 is a schematic structural diagram of an electromagnetic handwriting apparatus of an embodiment of the invention.

Fig. 2 is a block diagram of a receiving unit according to an embodiment of the present invention.

Fig. 3 is a configuration diagram of a transmission unit according to an embodiment of the present invention.

Fig. 4 is a circuit diagram of an embodiment of the present invention in which an analog switch is used in the transmitting section.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of an electromagnetic handwriting apparatus according to an embodiment of the invention. As shown in fig. 1, the electromagnetic handwriting apparatus 10 includes: a stylus 110 having an electromagnetic resonant circuit; an electromagnetic plate 120 having a transmission coil 121 and a reception coil 122 provided therein; a transmission unit 130 for driving a transmission coil 121 provided in the electromagnetic plate 120 to emit an electromagnetic wave; a receiving unit 140 connected to the receiving coil 122 and receiving the electromagnetic wave from the transmitting coil 121; and a control section 150. In the electromagnetic plate 120 of fig. 1, a plurality of sets of the transmission coil 121 and the reception coil 122 are provided, respectively, and are arranged perpendicular to each other in a grid shape.

As in the conventional electromagnetic handwriting device, in the present embodiment, when the transmitter is energized and an electromagnetic field is formed externally, the controller 150 controls the receiver 140 so as to scan the plurality of sets of receiver coils 122 one by one. When the stylus pen approaches/touches, the resonant circuit in the stylus pen 110 also receives the electromagnetic signal emitted from the transmitting coil 121 to generate electromagnetic induction and radiate the induced electromagnetic wave, thereby accurately detecting the approaching/touching position of the electromagnetic pen 110 by scanning the receiving coil one by one.

However, in the conventional electromagnetic handwriting device, the control unit 150 controls only the reception unit 140 so as to sequentially scan the reception coil 121. However, since the transmission coil 122 is always in an energized state, power consumption of the device becomes a major problem, and particularly in a mobile device, power needs to be obtained by the mobile device, and the transmission coil is not suitable for mobile applications.

Unlike the conventional electromagnetic handwriting apparatus, as shown in fig. 1, in the electromagnetic handwriting apparatus 10 according to the present embodiment, the control unit 150 receives the reception signal from the reception unit 140, obtains intensity information of the reception signal, and controls the transmission unit 130 to supply power of the transmission signal to the transmission coil 121 based on the intensity information of the reception signal. The details will be described below.

Fig. 2 is a block diagram of the receiving unit 140. The receiving coil 122 of the electromagnetic plate 120 senses the secondary electromagnetic wave generated by the electromagnetic pen, converts the electromagnetic wave signal into an electric signal, and inputs the electric signal to the receiving unit 140. As shown in fig. 2, the receiving section 140 includes an amplifier 141, an automatic gain controller 142, a quadrature decomposition circuit 143, an integration circuit 144, and an AD (Analog-Digital) conversion circuit 145. The amplifier 141 amplifies the received signal and outputs the amplified signal to the automatic gain control circuit 142. The automatic gain control circuit 142 performs automatic gain control and sends signals to the quadrature decomposition circuit 143 and the integration circuit 144 to detect the position of the electromagnetic pen 110, and the AD conversion circuit 145 converts an analog signal into a digital signal and sends the digital signal to the control unit 150 to perform corresponding processing. The receiving unit 140 simultaneously transmits the strength information indicating the received electromagnetic signal to the control unit 150.

When the intensity of the received electromagnetic signal is large, it means that the electromagnetic pen 110 is close to the electromagnetic plate 120, and conversely, it means that the electromagnetic pen 110 is far from the electromagnetic plate 120. Accordingly, the control unit 150 controls the transmission unit 130 to transmit with low power when the intensity of the received electromagnetic signal is high, and to transmit with high power on the contrary. When a user performs an input using the electromagnetic pen 110, there are operations of bringing the electromagnetic pen 110 close to and into contact with the electromagnetic plate 120 and operations of temporarily separating the electromagnetic pen 110 from the electromagnetic plate 120, and when the electromagnetic pen 110 is brought into contact with the electromagnetic plate 120, the user is generally inputting information, and when the electromagnetic pen 110 is separated from the electromagnetic plate 120, the interval between inputting information is generally set. The control part 150 controls the transmission power of the transmission part 130 such that the transmission part 130 transmits the electromagnetic wave with a small power when the electromagnetic pen 110 contacts the electromagnetic plate 120 when the user inputs information. At this time, since the distance between the electromagnetic pen 110 and the electromagnetic plate 120 is close enough, the detection of the position of the electromagnetic pen 110 is not affected. When the user stops inputting and leaves the electromagnetic pen 110 from the electromagnetic plate 120 temporarily, the control unit 150 controls the transmission unit 130 to transmit the electromagnetic wave with a large power, so that the position of the electromagnetic pen 110 can be detected quickly when the user starts inputting again, the continuity of the input operation of the user is not affected, and the power consumption of the electromagnetic handwriting device 10 can be reduced while maintaining its function.

The operation of the transmitter 130 when changing the transmission power will be described in detail below. Fig. 3 is a configuration diagram of the transmission unit 130. The transmission unit 130 is provided with a multiplexer 131. The multiplexer 131 switches the magnitude of the current supplied to the transmission coil 121 in accordance with a control signal from the control unit 150, so that the transmission power of the transmission unit 130 is reduced when the electromagnetic pen 110 comes into contact with or approaches the electromagnetic plate 120, and the transmission power of the transmission unit 130 is increased when the electromagnetic pen 110 is away from the electromagnetic plate 120.

Fig. 4 is a circuit configuration diagram of the multiplexer 131. In fig. 4, IC1 is a switch chip, and in this embodiment, an analog switch chip of type 74HC4051 is used, where X0 to X7 are output terminals, X is an input terminal, and three terminals GA, GB, and GC are used to receive signals sent from a controller, so as to select which channel of X0 to X7 is turned on. A plurality of load resistors having different resistance values are connected to X0 to X7, respectively, and the transmission power of the transmitter 130 can be switched so that the transmitter 130 can supply power to the transmission coil 121 at different powers, thereby switching the transmission power of the transmission coil 121.

In the present embodiment, since IC1 in transmission unit 130 employs an analog switch chip of 74HC4051, a 3-bit digital signal is transmitted from control unit 150 to terminals GA, GB, and GC, and the 8 types of transmission power of transmission unit 130 are switched. When the intensity of the electromagnetic signal received by the receiving coil 122 is high, the multi-way switch 131 is switched to a high-resistance path, and vice versa, so as to realize low power consumption of the electromagnetic handwriting device 10.

The present invention has been described above with reference to a specific example, and it will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment. For example, the analog switch IC1 shown in fig. 4 may not be used, and other control methods may be used. In the above-described embodiment, the control unit 150 outputs a digital signal to control the analog switch IC1 to supply power to the transmission coil 121 with 8 different types of power, but the number of transmission power may be set to be less than 8 to simplify the circuit configuration, or more than 8 types of transmission power may be used to continuously switch to ensure the reliability of position detection of the electromagnetic pen 110. Similarly, the control unit 150 may control the transmission power using an analog signal to adjust the power continuously variable.

According to the electromagnetic handwriting device 10, power consumption can be reduced when a user uses the electromagnetic handwriting device 10 for inputting, the electromagnetic handwriting device is suitable for the input requirement of a mobile device, and interference to other devices can be reduced.

Claims

1. An electromagnetic handwriting device, comprising:

an electromagnetic input pen;

an electromagnetic plate having a receiving coil and a transmitting coil;

a control unit;

a receiving unit that receives a signal from the receiving coil, processes the signal, and transmits the processed signal to the control unit; and

a transmission unit that processes a signal output from the control unit and transmits the signal to the transmission coil,

wherein,

the control unit transmits a control signal to the transmission unit based on the intensity of the signal received by the reception unit,

the transmitting unit adjusts power for transmitting a signal to the transmitting coil according to the control signal.

2. The electromagnetic handwriting device of claim 1, characterized in that:

the transmission unit has a multiplex switch for transmitting power of a signal to the transmission coil, and the power of the transmission signal is adjusted by gating different switches in the multiplex switch.

3. The electromagnetic handwriting device of claim 2, characterized in that: the multi-way selector switch is an analog switch.

4. The electromagnetic handwriting device of claim 1, characterized in that said receiving unit comprises:

an amplification circuit that amplifies a signal received from the reception coil;

an orthogonal processing circuit that performs orthogonal processing on the signal output from the amplification circuit; and

and an integrating circuit that integrates the signal output from the quadrature processing circuit and transmits the integrated signal to the control unit.