Capacitive motion detection device and input device using the same

• US 8,194,049 B2
• Filed: 07/29/2009
• Issued: 06/05/2012
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Oki, Toshiyuki
• Primary Examiner(s): Lao, Lun-Yi
• Assistant Examiner(s): Siddiqui, Md Saiful A
• Application Number:
  US12/511,984
• Publication Number:
  US 20090284496A1
• Time in Patent Office: 1,042 Days
• Field of Search: 345174-178, 178 1801- 1805, 463 37- 38
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors
• 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

Abstract

When a motion in the X-axis direction is detected, first electrodes are set as drive electrodes, and second electrodes are set as detection electrodes. A switching circuit performs switching so as to electrically connect a drive circuit to the first electrodes, electrically connect a first detection circuit to one of the second electrodes, and electrically connect a second detection circuit to the other second electrode. In a motion detection circuit in which connections are established in this manner, the drive circuit drives the drive electrodes, and then the position of an object to be detected in the X-axis direction is obtained from the difference between capacitances detected by the first and second detection circuits at this time.

Claims

1. A capacitive motion detection device comprising:

a device main body;

two or more detection electrode/drive electrode pairs in each of which a capacitance is formed between a detection electrode and a drive electrode, the detection electrode/drive electrode pairs being provided at detection positions of the device main body;

a motion detection circuit configured to detect motions of an object to be detected in two or more axis directions from a variation in a capacitance obtained in each of the detection electrode/drive electrode pairs, the motion detection circuit including a drive circuit and a detection circuit; and

a switching circuit configured to selectively coupling the drive circuit and the detection circuit to the detection electrode/drive electrode pairs,

wherein the device main body includes a substantially rectangular first area having four sides, the detection electrode/drive electrode pairs including;

first and second electrodes disposed on first two opposing sides of the first area;

third and fourth electrodes disposed on second two opposing sides of the first area; and

a fifth electrode disposed outside the first area,

and wherein the switching circuit is configured to;

connect the third and fourth electrodes to the drive circuit and the first and second electrodes to the detection circuit such that the motion detection circuit detects a motion of the object in a first axis direction;

connect the first and second electrodes to the drive circuit and the third and fourth electrodes to the detection circuit such that the motion detection circuit detects a motion of the object in a second axis direction crossing the first axis direction; and

connect the first, second, and fifth electrodes, or the third, forth, and fifth electrodes, to the motion detection circuit such that the motion detection circuit detects a motion of the object in a third axis direction crossing the first axis direction and the second axis direction.

2. The capacitive motion detection device according to claim 1, wherein at least one electrode of the detection electrode/drive electrode pairs is connected to the drive circuit when a motion in one axis direction is detected and is connected to the detection circuit when a motion in another axis direction is detected, in an alternate manner in a time sharing mode, using the switching means.

3. The capacitive motion detection device according to claim 1, wherein the detecting means detects a motion of the object to be detected from a difference value between capacitances detected by a plurality of electrodes connected to the detection circuit.

4. The capacitive motion detection device according to claim 1, wherein a display unit is provided in the first area.

5. The capacitive motion detection device according to claim 1, wherein the device main body further includes a second area different from the first area.

6. The capacitive motion detection device according to claim 5, wherein a display unit is provided in one of the first area and the second area.

7. The capacitive motion detection device according to claim 6, wherein an input unit is provided in the other of the first area and the second area, in which the display unit is not provided.

8. The capacitive motion detection device according to claim 7, wherein a capacitive sensor that detects approach of an object to be detected is provided near the input unit, and when a capacitance detected by the capacitive sensor is equal to or more than a threshold value, no motion is detected.

9. The capacitive motion detection device according to claim 5, wherein the device main body includes:

an angle measuring unit configured to measure an angle between the first area and the second area, and when a motion in the third axis direction is detected, correction is made using the angle measured by the angle measuring unit.

10. The capacitive motion detection device according to claim 1, wherein the device main body further includes a second area that is different from the first area, the fifth electrode being provided in the second area.

11. The capacitive motion detection device according to claim 10, wherein a display unit is provided in the first area or the second area.

12. The capacitive motion detection device according to claim 11, wherein an input unit is provided in the other of the first area and the second area, in which the display unit is not provided.

13. The capacitive motion detection device according to claim 10, wherein the device main body includes:

an angle measuring unit configured to measure an angle between the first area and the second area, and when a motion in the third axis direction is detected, correction is made using the angle measured by the angle measuring unit.

14. The capacitive motion detection device according to claim 1, wherein a capacitive sensor that detects approach of an object to be detected is provided, and when a capacitance detected by the capacitive sensor is equal to or more than a threshold value, no motion is detected.

15. An input device comprising:

the capacitive motion detection device according to claim 1; and

control means for operating the device main body on the basis of detection of a motion of the object to be detected, the detection being performed by the capacitive motion detection device, the control means being included in the device main body.

16. A capacitive motion detection device comprising:

a device main body including a first area and a second area different from the first area;

two or more detection electrode/drive electrode pairs in each of which a capacitance is formed between a detection electrode and a drive electrode, the detection electrode/drive electrode pairs being provided at detection positions of the device main body;

a motion detection circuit configured to detect motions of an object to be detected in two or more axis directions from a variation in a capacitance obtained in each of the detection electrode/drive electrode pairs, the motion detection circuit including a drive circuit and a detection circuit; and

a switching circuit configured to selectively coupling the drive circuit and the detection circuit to the detection electrode/drive electrode pairs,

wherein at least one electrode of the detection electrode/drive electrode pairs is provided in the first area, at least one electrode of the detection electrode/drive electrode pairs is provided in the second area, the motion detection circuit detecting motions in three axis directions,

and wherein the first area is substantially rectangular, a direction of a surface of the first area is an area to be operated for the object to be detected, detection electrode/drive electrode pairs formed by electrodes provided on two opposing sides of the first area are detection electrode/drive electrode pairs that detect motions in a first axis direction and a second axis direction, and detection electrode/drive electrode pairs formed by electrodes provided on two opposing sides of the first area and an electrode provided in the second area are detection electrode/drive electrode pairs that detect a motion in a third axis direction.

17. A capacitive motion detection method for detecting motions of an object to be detected in two or more axis directions from a variation in a capacitance obtained in each of two or more detection electrode/drive electrode pairs in each of which a capacitance is formed between a detection electrode and a drive electrode, using a motion detection circuit including a drive circuit and a detection circuit, the detection electrode/drive electrode pairs including:

first and second electrodes disposed on first two opposing sides of a substantially rectangular first area third and fourth electrodes disposed on second two opposing sides of the first area; and

a fifth electrode disposed outside the first area, the method comprising;

detecting a motion of the object in a first axis direction by connecting the third and fourth electrodes to a drive circuit and connecting the first and second electrodes to a detection circuit;

detecting a motion of the object in a second axis direction crossing the first axis direction by connecting the first and second electrodes to the drive circuit and connecting the third and fourth electrodes to the detection circuit; and

detecting a motion of the object in a third axis direction crossing the first axis direction and the second axis direction, by connecting the first, second, and fifth electrodes to the motion detection circuit, or connecting the third, forth, and fifth electrodes to the motion detection circuit.

18. The capacitive motion detection method according to claim 17, wherein a motion of the object to be detected is detected from a difference value between capacitances detected by a plurality of electrodes connected to the detection circuit.

19. The capacitive motion detection method according to claim 17, further comprising, when detecting the motion of the object in the third axis direction:

measuring an angle between the first area and the second area, and making a correction to the detected motion using the angle measured by the angle measuring unit.

20. The capacitive motion detection method according to claim 17, further comprising:

switching the connection of the electrodes of the detection electrode/drive electrode pairs to the drive circuit and the detection circuit in an alternate manner in a time sharing mode so as to detect the motion of the object in different axis directions.

21. The capacitive motion detection method according to claim 17, wherein at least one detection electrode/drive electrode pair is provided in a second area different from the first area, the method further comprising:

determining if an object is on or in a vicinity of the second area by detecting a motion of the object by connecting one electrode of the at least one detection electrode/drive electrode pair to the detection circuit and connecting another electrode of the at least one detection electrode/drive electrode pair to the drive circuit.