Point detecting device and method of same

• US 5,646,377 A
• Filed: 02/16/1995
• Issued: 07/08/1997
• Est. Priority Date: 04/08/1994
• Status: Expired due to Term

• Current Assignee: Wacom Co Limited (Wacom)
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Oda, Yasuo
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): Shankar, Vijay
• Application Number:
  US08/394,791
• Time in Patent Office: 873 Days
• Field of Search: 178/18, 178/19, 178/20, 345/156, 345/173, 345/179
• US Class Current: 178/18.07
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

The invention relates to a point detecting device and a method for providing coordinate information which is indicated by a pointing device. This point detecting device is adapted for a large scaled system which is required to be operated at a low cost and at high accuracy. The point detecting device transmits signals from both ends of the loop coil arrangement towards the pointing device, and/or receives at both ends the signals generated by the electromagnetic function between the loop coil arrangement and the pointing device. The errors owing to the variations caused in the signal level and phase in response to the propagation constant of the loop coil arrangement can be reduced by adding the received signal pair.

Claims

1. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising;

a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

a pair of signal receivers each of which is arranged at either end of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction so that the signal receiver can receive the signal generated by the electromagnetic function between the electromagnetic coupling means and the pointing device located above the electromagnetic coupling means; and

a signal processor including an adder for adding the received signals by the receivers and means for arithmetically operating the coordinate values of the pointing device.

2. The point detecting device as set forth in claim 1, wherein the electromagnetic coupling means comprises a pair of loop coils arranged close to each other, each one of which is connected to either one of the receiver pair.

3. The point detecting device as set forth in claim 1 further comprising a plurality of selecting switches arranged at both ends of the second axial direction of the electromagnetic coupling means for switching between one of the loop coil connected to one of the receivers and the other loop coil connected to the other receiver to establish the electromagnetic coupling means.

23. The point detecting device as set forth in claim 1, wherein the above described electromagnetic coupling means includes a pair of loop coils arranged close to each other and having reverse winding directions with each other, or a loop coil which is switched between the reverse winding directions by a switching means;

the above described received signal pair are the reverse of each other; and

the above described adding means is a differential amplifier to which the above described signal pair are input as two input signals.

24. The point detecting device as set forth in claim 1, wherein the above described one transmitter and the other transmitter form a common transmitter having respective transmission lines to both ends of the above described electromagnetic coupling means;

or the above described one receiver and the other receiver form a common receiver having respective transmission lines from both ends of the above described electromagnetic coupling means.

27. The point detecting device as set forth in claim 1, wherein the above described electromagnetic coupling means includes at least one of the loop coils and the turning end of each loop coil is provided on the substrate.

28. The point detecting device as set forth in claim 1, wherein the above described electromagnetic coupling means includes at least one of the loop coils and the turning end of each loop coil is covered with or arranged near effective magnetic shielding material or grounded conductive material.

4. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

a pair of signal transmitters each of which is arranged at either end of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction so that the transmitter can transmit signal to the electromagnetic coupling means; and

a signal processor for signal processing the signal generated by the electromagnetic function between the transmitted signal pair and the pointing device to obtain the coordinate values of the pointing device.

5. The point detecting device as set forth in claim 4, wherein the above described electromagnetic coupling means comprises a pair of loop coils arranged close to each other, each one of which is connected to either one of the transmitter pair.

6. The point detecting device as set forth in claim 4 further comprising a plurality of selecting switches arranged at both ends of the second axial direction of the electromagnetic coupling means for switching between one of the loop coil connected to one of the transmitter and the other loop coil connected to the other transmitter to establish the electromagnetic coupling means.

7. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

a pair of signal transmitters each of which is arranged at either end of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction;

a pair of signal receivers each of which is arranged at either end of the second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction so that the signal receiver can receive the signal generated by the electromagnetic function between the electromagnetic coupling means and the pointing device located above the electromagnetic coupling means;

a selecting means for selecting either the transmitter or receiver arranged at each end of the electromagnetic coupling means; and

a signal processor including an adder for adding the received signals by the receivers and means for operating arithmetically the coordinate values of the pointing device.

8. The point detecting device as set forth in claim 7, wherein the above described electromagnetic coupling means comprises a pair of loop coils arranged close to each other, each of which is connected to either of the transmitter and receiver through the selecting means.

9. The point detecting device as set forth in claim 7 further comprising a plurality of selecting switches arranged at both ends of the second axial direction of the electromagnetic coupling means for switching between one of the loop coil connected to one of the transmitter or receiver and the other loop coil connected to the other transmitter or receiver to establish the electromagnetic coupling means.

10. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising;

a plurality of first loop coil pairs each pair of which includes two loop coils arranged close to each other and pairs are arranged in parallel in a first axial direction within the point sensing area;

a plurality of second loop coil pairs each pair of which includes two loop coils arranged close to each other and pairs are arranged in parallel in a second axial direction intersected perpendicularly to the first axial direction;

a pair of signal transmitters each of which is arranged at either end of the second axial direction of the second loop coil pairs to transmit signal towards the above portion with respect to each coil of the second loop coil pairs;

a pair of signal receivers each of which is arranged at either end of the second axial direction of the first loop coil pairs to receive the signal generated by the electromagnetic function between the pointing device and each loop coil; and

a signal processor including an adder for adding the received signal pair with the receiver pair and means for operating arithmetically the coordinate values of the pointing device.

11. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising;

a plurality of loop coil pairs each pair of which includes two loop coils arranged close to each other and which are arranged in parallel in a first axial direction within the point sensing area;

a plurality of loop coil pairs each pair of which includes two loop coils arranged close to each other and pairs are arranged in parallel in a second axial direction intersected perpendicularly to the first axial direction;

a pair of signal transmitters each of which is arranged at either end of the second axial direction of the above described loop coil pair to transmit a signal towards the above portion with respect to each coil of the above described loop coil pair;

a pair of signal receivers each of which is arranged at either end of the first axial direction of the above described loop coil pair to receive the signal generated by the electromagnetic function between the pointing device and each loop coil; and

a signal processor including an adder for adding the received signal pair with the receiver pair and means for operating arithmetically the coordinate values of the pointing device.

12. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

a plurality of loop coil pairs each pair of which includes two loop coils arranged close to each other and which pairs are arranged in parallel in a first axial direction within the point sensing area;

a plurality of loop coils arranged in parallel in a second axial direction intersected perpendicularly to the first axial direction;

a signal transmitter arranged at one end of the first axial direction of the above described loop coil to transmit the signal towards the above portion with respect to the above described loop coil;

a pair of signal receivers each of which is arranged at either end of the second axial direction of the above described loop coil pair to receive the signal generated by the electromagnetic function between the pointing device and each loop coil of the loop coil pair; and

a signal processor including an adder for adding the received signal pair with the receiver pair and means for operating arithmetically the coordinate values of the pointing device.

13. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

a signal transmitter arranged at one end of the second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction;

a signal receiver arranged at the other end of the second axial direction of the electromagnetic coupling means so that the signal receiver can receive the signal generated by the electromagnetic function between the electromagnetic coupling means and the pointing device located above the electromagnetic coupling means; and

a signal processor for operating arithmetically the coordinate values of the pointing device.

14. The point detecting device as set forth in claim 13, wherein the above described electromagnetic coupling means comprises a pair of loop coils arranged close to each other;

the above described signal transmitter transmits signal to one of loop coil of the loop coil pair; and

the above described signal receiver receives signal from the other loop coil of the loop coil pair.

15. The point detecting device as set forth in claim 13 further comprising a plurality of selecting switches arranged at both ends of the second axial direction of the electromagnetic coupling means for switching between one of the loop coil connected to the transmitter and the other loop coil connected to the receiver to establish the electromagnetic coupling means.

16. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

a first amplifier which oscillates when a positive feedback loop is formed by the first amplifier, the pointing device, the above first electromagnetic coupling means one end of which is connected to an input terminal, and the second electromagnetic coupling means one end of which is connected to an output terminal;

a second amplifier which oscillates when a positive feedback loop is formed by the second amplifier, the pointing device, the above first electromagnetic coupling means the other end of which is connected to an input terminal, and the second electromagnetic coupling means the other end of which is connected to an output terminal;

a signal processor including an adder for adding the oscillated signal pair from the input terminals of the first and second amplifiers and means for operating arithmetically the coordinate values of the pointing device;

the above described first electromagnetic coupling means including a pair of loop coils arranged close to each other one of which is connected to the input terminal of the first amplifier and the other loop coil is connected to the input terminal of the second amplifier; and

the above described second electromagnetic coupling means including a pair of loop coils arranged close to each other one of which is connected to the output terminal of the first amplifier and the other loop coil is connected to the output terminal of the second amplifier.

17. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising;

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

an amplifier which oscillates when a positive feedback loop is formed by the amplifier, the pointing device, and the above first and second electromagnetic coupling means;

an adding means for adding the signals from both ends of the first electromagnetic coupling means and inputting the added signal to the above described amplifier;

an outputting means for outputting the output from the above described amplifier to both ends of the electromagnetic coupling means;

a signal processor for operating arithmetically the oscillated signal from the input terminal of the above described amplifier to provide the coordinate values of the pointing device;

the above described first electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the input terminal of the above described adder; and

the above described second electromagnetic coupling means including a pair of loop coils arranged close to each other opposite ends of which are respectively connected to the output terminal of the above described amplifier.

18. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

an amplifier which oscillates when a positive feedback loop is formed by the amplifier, the pointing device, the above described first and second electromagnetic coupling means;

a first switching means for selecting either signal from either end of the first electromagnetic coupling means to input the selected signal to the above described amplifier;

a second switching means for selecting either end of the second electromagnetic coupling means to output the signal from the above described amplifier;

a signal processor including an adding means for adding first and second oscillated signals through the input terminal of the above described amplifier and means for operating arithmetically the coordinate values of the pointing device, the first oscillated signal being fed to the adding means when the first switching means selects one end of the first electromagnetic coupling means and the second switching means selects one end of the second electromagnetic coupling means, and the second oscillated signal being fed to the adding means when the first switching means selects the other end of the first electromagnetic coupling means and the second switching means selects the other end of the second electromagnetic coupling means;

the above described first electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the switching terminal of the above described first switching means; and

the above described second electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the switching terminal of the second switching means.

19. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

an amplifier which oscillates when a positive feedback loop is formed by the amplifier, the pointing device, and the above first and second electromagnetic coupling means, one end of the second electromagnetic coupling means of which is connected to an output terminal of the amplifier;

an adding means for adding the signals from both ends of the first electromagnetic coupling means and inputting the added signal to the above described amplifier;

a signal processor for operating arithmetically the oscillated signal from the input terminal of the above described amplifier to provide the coordinate values of the pointing device;

the above described first electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the input terminal of the above described adder; and

the above described second electromagnetic coupling means including a loop coil.

20. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

an amplifier which oscillates when a positive feedback loop is formed by the amplifier, the pointing device, and the above first and second electromagnetic coupling means, one end of the second electromagnetic coupling means of which is connected to an output terminal of the amplifier;

a switching means for selecting either signal from either end of the first electromagnetic coupling means to input the selected signal to the above described amplifier;

a signal processor including an adding means for adding first and second oscillated signals through the input terminal of the above described amplifier and means for operating arithmetically the coordinate values of the pointing device, the first oscillated signal being fed to the adding means when the switching means selects one end of the first electromagnetic coupling means and the second oscillated signal being fed to the adding means when the switching means selects the other end of the first electromagnetic coupling means;

the above described first electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the selecting terminal of the above described switching means; and

the above described second electromagnetic coupling means including a loop coil.

21. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

an amplifier which oscillates when a positive feedback loop is formed by the amplifier, the pointing device, and the above first and second electromagnetic coupling means, one end of the first electromagnetic coupling means of which is connected to an input terminal of the amplifier;

an outputting means for outputting the output from the amplifier to both ends of the second electromagnetic coupling means;

a signal processor for operating arithmetically the oscillated signal from the input terminal of the above described amplifier to provide the coordinate values of the pointing device;

the above described first electromagnetic coupling means including a loop coil; and

the above described second electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the output terminal of the above described amplifier.

22. A point detecting device including a point sensing area and a pointing device capable of moving over the point sensing area, further comprising:

first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

an amplifier which oscillates when a positive feedback loop is formed by the amplifier, the pointing device, and the above first and second electromagnetic coupling means, one end of the first electromagnetic coupling means of which is connected to an input terminal of the amplifier;

a switching means for selecting either end of the second electromagnetic coupling means to output the selected signal from the above described amplifier;

a signal processor including an adding means for adding first and second oscillated signals through the input terminal of the above described amplifier and means for operating arithmetically the coordinate values of the pointing device, the first oscillated signal being fed to the adding means when the switching means selects one end of the second electromagnetic coupling means and the second oscillated signal being fed to the adding means when the switching means selects the other end of the second electromagnetic coupling means;

the above described first electromagnetic coupling means including a loop coil; and

the above described second electromagnetic coupling means including a pair of loop coils arranged close to each other, opposite ends of which are respectively connected to the switching terminal of the above described switching means.

25. A point detecting device which detects and processes the signal generated by an electromagnetic function between a pointing device and a plurality of electromagnetic coupling means arranged in the point detecting direction so as to obtain the coordinate values of the pointing device, wherein one of the above described electromagnetic coupling means includes a pair of loop coils arranged close to each other, each one of which has at least one of connection end for transmitting or receiving the signal and at least one turning end, or a loop coil having a switching means to switch the positions of the connection end and the turning end;

and

the above described point detecting device further comprising a decision means for deciding the substantial position of the pointing device according to the detected signal generated in transmitting or receiving mode which employs both loop coils of the above described loop coil pair or both switching positions of the above switching means, or according to the detected position of at least one of the cross loop coils arranged perpendicularly to the loop coil pair or the single loop coil, which are selectively used for transmitting or receiving signals; and

receiving means or transmitting means, when the pointing device is located above the region including one loop coil of the above described loop coil pair or at least the turning end of one switching position, the above receiving means receiving at least one of the signals generated by the other loop coil or the other switching position, and the above transmitting means transmitting an actuating signal to generate the signal by the other loop coil or the other switching position.

26. The point detecting device as set forth in claim 25, wherein the above described region including at least the turning end is defined from the centre of the above described electromagnetic coupling means to the above described turning end.

29. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for:

providing a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

receiving alternately or simultaneously signals generated by the electromagnetic function between the electromagnetic coupling means and the pointing device located above the electromagnetic coupling means, at both or either end of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction; and

performing a signal processing step including an adding operation for adding the received signal pair for arithmetically operating the coordinate values of the pointing device.

30. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for:

providing a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

transmitting alternately or simultaneously a pair of signals to the above space of the electromagnetic coupling means from both ends of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction; and

processing the signals generated by the electromagnetic function between the pointing device and the transmitted signal pairs to arithmetically operate the coordinate values of the pointing device.

31. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for;

providing a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

simultaneously transmitting and receiving signals to the above space of the electromagnetic coupling means from both ends of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction, or transmitting and receiving a signal from one end of the above described both ends of the second axial direction of the electromagnetic coupling means and then transmitting and receiving another signal from the other end of the above described both ends so as to receive the signals generated by the electromagnetic function between the electromagnetic coupling means and the pointing device located above the electromagnetic coupling means; and

performing a signal processing step including an adding operation for adding the received signal pair for arithmetically operating the coordinate values of the pointing device.

32. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for;

providing a plurality of electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

transmitting a signal to the above space of the electromagnetic coupling means from one end of a second axial direction of the electromagnetic coupling means intersected perpendicularly to the first axial direction;

receiving the signal generated by the electromagnetic function between the pointing device and the electromagnetic coupling means; and

processing the received signal to arithmetically operate the coordinate values of the pointing device.

33. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for:

providing a plurality of first electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

providing a plurality of second electromagnetic coupling means arranged in parallel in a second axial direction intersected perpendicularly to the first axial direction;

simultaneously transmitting a pair of signals to the above space of the electromagnetic coupling means from both ends of the first axial direction of the second electromagnetic coupling means;

simultaneously receiving the signal pair generated by the electromagnetic function between the pointing device and the electromagnetic coupling means at both ends of the second axial direction of the first electromagnetic coupling means; and

performing a signal processing step including an adding operation for adding the received signal pair for arithmetically operating the coordinate values of the pointing device.

34. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for providing a plurality of first electromagnetic coupling means arranged in parallel in a first axial direction within the point sensing area;

providing a plurality of second electromagnetic coupling means arranged in parallel in a second axial direction intersected perpendicularly to the first axial direction;

transmitting a signal to the above space of the electromagnetic coupling means from one of both ends of the first axial direction of the second electromagnetic coupling means;

simultaneously receiving the signal generated by the electromagnetic function between the pointing device and the electromagnetic coupling means at both ends of the second axial direction of the first electromagnetic coupling means; and

performing a signal processing step including an adding operation for adding the received signal pair for arithmetically operating the coordinate values of the pointing device.

35. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for providing first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

connecting an input terminal of a first amplifier to one end of the above first electromagnetic coupling means;

connecting an output terminal of the first amplifier to one end of the above second electromagnetic coupling means;

oscillating the first amplifier when a positive feedback loop is formed by the first amplifier, the pointing device, and the above described first and second electromagnetic coupling means;

connecting an input terminal of a second amplifier to the other end of the above first electromagnetic coupling means;

connecting an output terminal of the second amplifier to the other end of the above second electromagnetic coupling means;

oscillating the second amplifier when a positive feedback loop is formed by the second amplifier, the pointing device, and the above described first and second electromagnetic coupling means; and

performing a signal processing step including an adding operation for adding the oscillated signal pair from the input terminals of the first and second amplifiers for arithmetically operating the coordinate values of the pointing device signal.

36. A point detecting method employing a point sensing area and a pointing device capable of moving over the point sensing area, further comprising steps for:

providing first and second electromagnetic coupling means which are prevented from electromagnetic coupling with each other;

connecting an input terminal of an amplifier to both ends of the first electromagnetic coupling means through an adder and an output terminal of the amplifier to both ends of the second electromagnetic coupling means;

oscillating the amplifier when a positive feedback loop is formed by the amplifier, the pointing device, and the above described first and second electromagnetic coupling means; and

processing the oscillated signal from the input terminal of the above described amplifier to arithmetically operate the coordinate values of the pointing device.

37. A point detecting method which detects and processes the signal generated by electromagnetic function between a pointing device and a plurality of electromagnetic coupling means arranged in the point detecting direction so as to obtain the coordinate values of the pointing device, further comprising steps for:

providing one of the above described electromagnetic coupling means which includes a pair of loop coils arranged close to each other, each one of which has at least one connection end for transmitting or receiving the signal and at least one turning end, or a loop coil having a switching means to switch the positions of the connection end and the turning end;

when the pointing device is located above the region including one loop coil of the above described loop coil pair or at least the turning end of one switching position, receiving at least one of signals generated by the other loop coil or the other switching position, or transmitting an actuating signal to generate the signal by the other loop coil or the other switching position.

38. The point detecting method as set forth in claim 37, wherein the above described region including at least the turning end is defined from the centre of the above described electromagnetic coupling means to the above described turning end.