Sensor sheet

• US 7,174,793 B2
• Filed: 09/19/2003
• Issued: 02/13/2007
• Est. Priority Date: 09/24/2002
• Status: Expired due to Fees

• Current Assignee: Nitta Corporation
• Original Assignee: Nitta Corporation
• Inventors: Morimoto, Hideo
• Primary Examiner(s): Cygan; Michael
• Assistant Examiner(s): DAVIS, OCTAVIA L
• Application Number:
  US10/665,278
• Publication Number:
  US 20040055396A1
• Time in Patent Office: 1,243 Days
• Field of Search: 738/620.45, 738/620.4, 738/620.46, 738/620.43, 735/143.2, 324/686, 324/681, 438/50
• US Class Current: 73/862.045
• CPC Class Codes: G01L 1/146 for measuring force distributions, e.g. using force arrays G01L1/148 takes precedence
• CPC Class Codes: G01L 1/148 using semiconductive material, e.g. silicon
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G01L 5/165 using variations in capacitance

Abstract

In a sensor sheet of the present invention, a large number of sensor cells, each having capacitance element electrodes corresponding to an X-axis direction, a Y-axis direction and a Z-axis direction and a displacement electrode arranged to form capacitance elements between the capacitance element electrodes and the displacement electrode, are arranged in matrix. This arrangement enables measurement of a distribution of three-dimensional components of the force applied from outside over the overall sensor sheet on the basis of the components of force detected in each of the large number of sensor cells.

Claims

1. A sensor sheet comprising:

a plurality of sensors arranged in a matrix;

an elastic supporting member configured to partition at least two of the plurality of sensors from each other; and

a cover layer configured to cover the plurality of sensors,

wherein at least one of the plurality of sensors comprises;

a plurality of first electrodes corresponding to a plurality of directions, respectively;

a second electrode supported by the elastic supporting member and facing the plurality of first electrodes such that capacitance elements are formed by the plurality of first electrodes and the second electrode, wherein the second electrode is configured to be displaceable toward the plurality of first electrodes when an external force is applied thereto; and

a core member is disposed between the cover layer and the second electrode and formed of rigid material arranged to permit independent movement thereof, wherein the core member is individual to the at least one of the plurality of sensors;

wherein the at least one of the plurality of sensors is capable of identifying the external force in a multidimensional direction based on detection of changes in capacitance of the capacitance elements caused by changes in distances between the plurality of first electrodes and the second electrode, and

wherein distribution of force applied to the cover layer is identified based on the forces identified by at least two of the plurality of the sensors.

2. The sensor sheet according to claim 1, wherein the at least one of the plurality sensors further comprises a third electrode grounded and arranged in a proximity of the first electrodes,

wherein the second electrode contacts the third electrode when the external force is applied thereto, and

wherein a signal is input to the plurality of first electrodes when the second electrode and the third electrode are in contact with each other.

3. The sensor sheet according to claim 1, wherein a surface of the cover layer to receive the external force applied is formed to have substantially no projections and depressions.

4. The sensor sheet according to claim 2, wherein a surface of the cover layer to receive the external force applied is formed to have substantially no projections and depressions.

5. The sensor sheet according to claim 2, wherein the second electrode comprises a protrusion to contact the third electrode.

6. The sensor sheet according to claim 2, wherein the at least one of the plurality of sensors comprises a insulating layer to cover the plurality of the first electrode.

7. The sensor sheet according to claim 2, wherein the changes in capacitance is detected using the signal that is input to the plurality of first electrodes when the second electrode contacts the third electrode.

8. A sensor sheet comprising:

a plurality of sensors arranged in a matrix;

an elastic supporting member configured to partition at least two of the plurality of sensors from each other; and

a cover layer configured to cover the plurality of sensors,

wherein at least one of the plurality of sensors comprises;

a plurality of first electrodes corresponding to a plurality of directions, respectively;

a second electrode supported by the elastic supporting member and facing the plurality of first electrodes and configured to be displaceable toward the plurality of first electrodes when an external force is applied thereto;

a pressure-sensitive resistance member arranged between the plurality of first electrodes and the second electrode; and

a core member is disposed between the cover layer and the second electrode and formed of rigid material arranged to permit independent movement thereof, wherein the core member is individual to the at least one of the plurality of sensors;

wherein the at least one of the plurality of sensors is capable of identifying the external force in a multidimensional direction based on detection of changes in resistance between the plurality of first electrodes and the second electrode, and

wherein distribution of force applied to the cover layer is identified based on the forces identified by at least two of the plurality of the sensors.

9. The sensor sheet according to claim 8, wherein a surface of the cover layer to receive the external force applied is formed to have substantially no projections and depressions.