POINTING MEMBER, POSITION DETECTION APPARATUS AND POSITION DETECTION METHOD

• US 20110155479A1
• Filed: 08/24/2010
• Published: 06/30/2011
• Est. Priority Date: 12/25/2009
• Status: Active Grant

• Current Assignee: Wacom Co Limited (Wacom), Wacon Company Limited
• Original Assignee: Wacom Co Limited (Wacom)
• Inventors: Oda, Yasuo, Sugiyama, Yoshihisa
• Granted Patent: US 9,218,070 B2
• Time in Patent Office: Days
• US Class Current: 178/18.06
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

Methods and apparatus are provided to further facilitate detection not only of a position on a position detector pointed to by a pointing member, but also of information other than the position information such as pen pressure applied to the pointing member, in a position detection apparatus of the electrostatic coupling type. In one embodiment, a pointing member includes a first electrode substantially in the form of a rod, a substantially cylindrical second electrode disposed in such a manner as to surround the first electrode, and a transmission signal production section for producing a signal of a first frequency f1 and another signal of a second frequency f2 different from the first frequency f1 and controlling a phase difference between the signals in response to pressure applied to the pointing member. On a position detector side, the signal of the first frequency f1 is used for position detection of the pointing member, and the phase difference is used for detection of information other than the position information such as pen pressure on the pointing member. Alternatively, a pulse signal having a pulse width corresponding to pressure applied to the pointing member is produced, and on the position detector side, the position, pen pressure and so forth are detected from the pulse signal and the pulse width.

Claims

1. A position detection apparatus, comprising:

a pointing member for transmitting a signal for position pointing; and

a position detector including a sensor section that is configured to be pointed to at a position thereof by said pointing member and to receive the signal for position pointing transmitted from said pointing member;

wherein said position detector is configured to detect the position on said sensor section pointed to by said pointing member based on the signal for position pointing received by said sensor section; and

wherein said pointing member includes a transmission signal production section configured to produce a signal of a first frequency and a signal of a second frequency that is different from the first frequency and to control production timings of the signal of the first frequency and the signal of the second frequency in response to a pressing force applied to said pointing member when it points to a position on said sensor section, and wherein said position detector is configured to detect the position on said sensor section pointed to by said pointing member based on at least one of the signal of the first frequency and the signal of the second frequency and to detect the pressing force applied to said pointing member when it points to the position on said sensor section based on a phase difference between the signal of the first frequency and the signal of the second frequency.

2. The position detection apparatus according to claim 1, wherein said pointing member includes a pen tip projecting from a housing of said pointing member and used for position pointing, and said transmission signal production section controls the production timings of the signal of the first frequency and the signal of the second frequency in response to the pressing force to said pen tip.

3. The position detection apparatus according to claim 2, wherein said pointing member includes a pressure detection element for detecting the pressing force to said pen tip, and said transmission signal production section controls the production timings of the signal of the first frequency and the signal of the second frequency based on a signal from said pressure detection element.

4. The position detection apparatus according to claim 2, wherein said pen tip includes a conductive member, and at least one signal produced by said transmission signal production section is transmitted through said pen tip.

5. The position detection apparatus according to claim 1, wherein said sensor section includes an excitation coil, and said pointing member includes a power production circuit for receiving an excitation signal from said excitation coil to produce power for driving said transmission signal production section provided in said pointing member.

6. The position detection apparatus according to claim 1, wherein said position detector is configured to detect that said pointing member is in a touching state with said sensor section or in a hovering state with respect to said sensor section based on a phase difference between the signal of the first frequency and the signal of the second frequency or on the presence of the signal of the first frequency and the signal of the second frequency.

7. The position detection apparatus according to claim 1, wherein said pointing member has an operation switch provided on a side face thereof, and said transmission signal production section is further configured to produce a signal of a third frequency in response to an operation of said operation switch.

8. The position detection apparatus according to claim 1, wherein said sensor section includes a plurality of conductors disposed in a first direction and another plurality of conductors disposed in a second direction intersecting with the first direction, and wherein said position detector further includes:

a second transmission signal production section configured to produce signals of a predetermined frequency; and

a changeover section configured to selectively supply the signals produced by said second transmission signal production section to the plurality of conductors disposed in the first direction and to selectively receive signals produced in the plurality of conductors disposed in the second direction, wherein said changeover section is controlled to permit detection of a position on said sensor section pointed to by another pointing member that is different in type from said pointing member.

9. The position detection apparatus according to claim 8, wherein said changeover section is configured to control conductor selection in a predetermined period so that said position detector detects signals produced in the conductors disposed in both the first direction and the second direction to detect a position pointed to by said pointing member, while the signals produced by said second transmission signal production section are supplied to said conductors disposed in the first direction and signals produced in said conductors disposed in the second direction are detected by said position detector to detect a position on said sensor section pointed to by the other pointing member that is different in type from said pointing member.

10. The position detection apparatus according to claim 9, wherein the other pointing member that is different in type is a finger.

11. The position detection apparatus according to claim 8, wherein said second transmission signal production section is configured to produce a plurality of different kinds of signals such that the produced plural different kinds of signals are supplied to the plurality of conductors disposed in said first direction.

12. The position detection apparatus according to claim 8, wherein said second transmission signal production section is configured to produce a signal having a frequency that is different from the first frequency and the second frequency, which is different from the first frequency, both of which being produced by said transmission signal production section provided in said pointing member.

13. A pointing member which includes a pen tip projecting from a housing and is used for position pointing, comprising:

a transmission signal production section that is configured to produce a transmission signal corresponding to a pressing force applied to said pen tip, wherein said transmission signal production section is configured to produce a signal of a first frequency and another signal of a second frequency different from the first frequency and to control production timings of the signal of the first frequency and the signal of the second frequency in response to a pressing force applied to said pen tip.

14. The pointing member according to claim 13, further comprising a pressure detection element for detecting the pressing force applied to said pen tip, wherein the transmission signal production section is configured to control the production timings of the signal of the first frequency and the signal of the second frequency based on a signal from said pressure detection element.

15. The pointing member according to claim 13, further comprising an operation switch provided on a side face of the housing thereof, wherein the transmission signal production section is further configured to produce a signal of a third frequency in response to an operation of said operation switch.

16. The pointing member according to claim 13, wherein said pen tip includes a conductive member, and at least one signal produced by said transmission signal production section is transmitted through said pen tip.

17. A position detection apparatus, comprising:

a pointing member for transmitting a signal for position pointing; and

a position detector including a sensor section that is configured to be pointed to at a position thereof by said pointing member and to receive the signal for position pointing transmitted from said pointing member;

wherein said position detector is configured to detect the position on said sensor section pointed to by said pointing member based on the signal for position pointing received by said sensor section; and

wherein said pointing member includes a transmission signal production section configured to produce a predetermined pulse signal and to control a pulse width of the predetermined pulse signal in response to a pressing force applied to said pointing member when it points to a position on said sensor section, and wherein said position detector is configured to detect the position on said sensor section pointed to by said pointing member based on the presence of the predetermined pulse signal and to detect the pressing force applied to said pointing member when it points to the position on said sensor section based on a pulse width of the predetermined pulse signal.

18. A pointing member which includes a pen tip projecting from a housing and used for position pointing, comprising:

a transmission signal production section configured to produce a transmission signal corresponding to a pressing force applied to said pen tip, wherein said transmission signal production section is configured to produce a predetermined pulse signal with a pulse width that is variable in response to the pressing force applied to said pen tip.

19. A position detection method to detect a position on a sensor section pointed to by a pointing member and to detect pen pressure on the pointing member, comprising:

receiving a signal of a first frequency and a signal of a second frequency different from the first frequency from the pointing member wherein production timings of the signal of the first frequency and the signal of the second frequency is related to a pressing force applied to the pointing member when it points to a position on the sensor section;

detecting a position on the sensor section pointed to by the pointing member based on at least one of the signal of the first frequency and the signal of the second frequency; and

detecting the pressing force applied to the pointing member when it points to the position on the sensor section based on a phase difference between the signal of the first frequency and the signal of the second frequency.

20. A method of operating a pointing member to transmit an indication of a pressing force on a pen tip of the pointing member, comprising:

transmitting a signal of a first frequency and a signal of a second frequency different from the first frequency, and

controlling production timings of the signal of the first frequency and the signal of the second frequency in response to a pressing force to the pen tip.