CAPACITIVE MOTION DETECTION DEVICE AND INPUT DEVICE USING THE SAME

• US 20090284496A1
• Filed: 07/29/2009
• Published: 11/19/2009
• 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
• Granted Patent: US 8,194,049 B2
• Time in Patent Office: Days
• 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;

detecting means 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 the detection electrode/drive electrode pairs, the detecting means including a drive circuit and a detection circuit; and

switching means for changing connections to the detection electrode/drive electrode pairs,

wherein the switching means can change a connection of at least one electrode of the detection electrode/drive electrode pairs to the drive circuit and the detection circuit.

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 detection electrode/drive electrode pairs include first and second electrodes disposed in a first axis direction with a space between the first and second electrodes and third and fourth electrodes disposed in a second axis direction that crosses the first axis direction with a space between the third and fourth electrodes,

the switching means connects the third and fourth electrodes to the drive circuit and connects the first and second electrodes to the detection circuit, and the detecting means detects a motion of the object to be detected in the first axis direction, and

the switching means connects the first and second electrodes to the drive circuit and connects the third and fourth electrodes to the detection circuit, and the detecting means detects a motion of the object to be detected in the second axis direction.

4. The capacitive motion detection device according to claim 3, 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.

5. The capacitive motion detection device according to claim 3, wherein the first, second, third, and fourth electrodes are disposed on four sides of a rectangular first area, the first and second electrodes are disposed on two opposing sides of the first area, and the third and fourth electrodes are disposed on the other two sides of the first area.

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

7. The capacitive motion detection device according to claim 5, wherein the device main body includes a second area in which at least one electrode of the detection electrode/drive electrode pairs is provided, the second area being different from the first area, and the detecting means detects motions in three axis directions.

8. The capacitive motion detection device according to claim 7, wherein detection electrode/drive electrode pairs constituted 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 that crosses the first axis direction and the second axis direction.

9. The capacitive motion detection device according to claim 7, wherein a display unit is provided in one area of the first area and the second area.

10. The capacitive motion detection device according to claim 9, wherein input means is provided in one area of the first area and the second area, the display unit being not provided in the one area.

11. The capacitive motion detection device according to claim 8, wherein the device main body includes angle measuring means for measuring 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 means.

12. The capacitive motion detection device according to claim 1, wherein the device main body includes a first area and a second area that is different from the first area, at least one electrode of the detection electrode/drive electrode pairs being provided in the first area, at least one electrode of the detection electrode/drive electrode pairs being provided in the second area, and the detecting means detects motions in three axis directions.

13. The capacitive motion detection device according to claim 12, wherein the first area is 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 constituted 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 constituted 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.

14. The capacitive motion detection device according to claim 12, wherein a display unit is provided in the first area or the second area.

15. The capacitive motion detection device according to claim 14, wherein input means is provided in one area of the first area and the second area, the display unit being not provided in the one area.

16. The capacitive motion detection device according to claim 12, wherein the device main body includes angle measuring means for measuring an angle between the first area and the second area, and when a motion in three axis directions is detected, correction is made using the angle measured by the angle measuring means.

17. 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.

18. The capacitive motion detection device according to claim 10, wherein a capacitive sensor that detects approach of an object to be detected is provided near the input means, and when a capacitance detected by the capacitive sensor is equal to or more than a threshold value, no motion is detected.

19. An input device comprising:

a device main body that includes 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.

20. 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 the detection electrode/drive electrode pairs, switching means for changing connections to the detection electrode/drive electrode pairs, and detecting means configured to include a drive circuit and a detection circuit,

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.

21. The capacitive motion detection method according to claim 20, wherein the detection electrode/drive electrode pairs include first and second electrodes disposed in a first axis direction with a space between the first and second electrodes and third and fourth electrodes disposed in a second axis direction that crosses the first axis direction with a space between the third and fourth electrodes,

in a state in which the switching means is switched so as to connect the third and fourth electrodes to the drive circuit and connect the first and second electrodes to the detection circuit, a motion of the object to be detected in the first axis direction is detected, and

in a state in which the switching means is switched so as to connect the first and second electrodes to the drive circuit and connect the third and fourth electrodes to the detection circuit, a motion of the object to be detected in the second axis direction is detected.

22. The capacitive motion detection method according to claim 21, 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.