Hybrid sensor including electrostatic capacitance sensor

• US 20050257628A1
• Filed: 05/05/2005
• Published: 11/24/2005
• Est. Priority Date: 05/10/2004
• Status: Active Grant

• Current Assignee: Fujikura Limited
• Original Assignee: Fujikura Limited
• Inventors: Nakamura, Yasushi, Nikaido, Shinichi, Misaki, Nobumasa, Kamijima, Akira
• Granted Patent: US 7,337,681 B2
• Time in Patent Office: Days
• US Class Current: 73/862.541
• CPC Class Codes: B60N 2/002 Seats provided with an occupancy detection means mounted therein or thereon detection means responsive to presence or absence of children B60N2/266
• CPC Class Codes: B60N 2/58 Seat coverings
• CPC Class Codes: B60N 2210/12 Capacitive; Electric field
• CPC Class Codes: B60N 2210/40 Force or pressure sensors
• CPC Class Codes: H01H 2203/02 Interspersed fingers
• CPC Class Codes: H01H 2239/006 Containing a capacitive switch or usable as such
• CPC Class Codes: H01H 3/141 Cushion or mat switches

Abstract

A hybrid sensor is formed by stacking a plurality of flexible sheets each provided with electrode patterns. The hybrid sensor includes a contact pressure sensor which has switches turning on or off by a pressure load, and an electrostatic capacitance sensor which detects a nearby object without contacting the object. The electrode patterns include a switching electrode pattern as the switch of the contact pressure sensor and a detecting electrode pattern as the detecting electrode of the electrostatic capacitance sensor. The detecting electrode is formed to cover substantially the entire area other than the area on which the switching electrode pattern is formed.

Claims

1. A hybrid sensor, comprising:

a plurality of stacked, flexible sheets;

wherein a first sheet of the plurality of flexible sheets comprises;

a switching electrode pattern, and

a detecting electrode pattern,

wherein the detecting electrode pattern substantially covers the entire area of the first sheet.

2. The hybrid sensor as recited in claim 1, wherein:

a second sheet of the plurality of flexible sheets comprises an insulating sheet having a plurality of holes therein;

a third sheet of the plurality of flexible sheets comprises a ground electrode pattern, and

the location of the holes in the second sheet and the location of the ground electrode pattern on the third sheet correspond to the location of the switching electrode pattern on the first sheet.

3. The hybrid sensor as recited in claim 2, wherein:

the switching electrode pattern is formed on an underside of the first sheet, facing the second and third sheets; and

the ground electrode pattern is formed on a topside of the third sheet, facing the second and first sheets, such that when pressure is applied to the first and third sheets, the switching electrode pattern contacts the ground electrode pattern through the holes in the second sheet.

4. The hybrid sensor as recited in claim 1, wherein the first sheet further comprises:

a guard electrode pattern, supplied with the same electric potential as supplied to the detecting electrode pattern and positioned on the first sheet in order to block parasitic capacitance between the detecting electrode pattern and the switching electrode pattern.

5. An electrostatic capacitance sensor, comprising:

a plurality of stacked, flexible sheets

wherein a first sheet of the plurality of flexible sheets comprises;

a detecting electrode pattern;

a second circuit pattern; and

a guard electrode pattern supplied with the same electric potential as supplied to the detecting electrode pattern and positioned on the first sheet in order to block parasitic capacitance between the detecting electrode pattern and the second circuit pattern; and

a detecting circuit connected to the detecting electrode pattern, which detects an electrostatic capacitance of said detecting electrode pattern.

6. The electrostatic capacitance sensor according to claim 5, wherein:

a second sheet of the plurality of flexible sheets comprises a ground electrode pattern.

7. The electrostatic capacitance sensor as recited in claim 6, wherein the detecting electrode pattern, the second circuit pattern, and the guard electrode pattern are formed on the same surface of the first sheet.

8. A hybrid sensor comprising:

a plurality of stacked, flexible sheets;

wherein a first sheet of the plurality of flexible sheets comprises;

a switching electrode pattern and a ground electrode pattern, together forming a plurality of land portions, and

a detecting electrode pattern;

wherein the detecting electrode pattern substantially covers the entire area of the first sheet.

9. The hybrid sensor according to claim 8, wherein the first sheet further comprises a plurality of slits surrounding the land portions and separating the land portions from the detecting electrode pattern.

10. The hybrid sensor according to claim 8, wherein:

a second sheet of the plurality of flexible sheets comprises a insulating sheet having a plurality of holes therein;

a third sheet of the plurality of flexible sheets comprises a conductive short circuit pattern; and

wherein the location of the holes in the second sheet and the location of the short circuit pattern on the third sheet correspond to the location of the land portions of the switching electrode pattern and the ground electrode pattern on the first sheet.

11. The hybrid sensor according to claim 10, wherein:

the first sheet further comprises a first plurality of slits surrounding the land portions and separating the land portions from the detecting electrode pattern;

the second sheet further comprises a second plurality of slits surrounding the holes;

the third sheet further comprises a third plurality of slits surrounding the short circuit pattern; and

the locations of the first, second, and third slits correspond such that when the first, second, and third sheets are stacked together, the first, second, and third slits form through slits.

12. The hybrid sensor according to claim 10, wherein:

the switching electrode pattern and the ground electrode pattern are formed on an underside of the first sheet, facing the second and third sheets, and the short circuit pattern is formed on a topside of the third sheet, facing the second and first sheets, such that when pressure is applied to the first and third sheets, the switching electrode pattern and the ground electrode pattern contact the short circuit pattern through the holes in the second sheet.

13. The hybrid sensor according to claim 8, wherein the first sheet further comprises:

a guard electrode pattern, supplied with the same electric potential as supplied to the detecting electrode pattern and positioned on the first sheet in order to block parasitic capacitance between the detecting electrode pattern and the switching electrode pattern.

14. The hybrid sensor according to claim 13, wherein:

the first sheet further comprises a first plurality of slits surrounding the land portions and the guard electrode pattern and separating the land portions and the guard electrode pattern from the detecting electrode pattern;

the second sheet further comprises a second plurality of slits surrounding the holes;

the third sheet further comprises a third plurality of slits surrounding the short circuit pattern; and

the locations of the first, second, and third slits correspond such that when the first, second, and third sheets are stacked together, the first, second, and third slits form through slits.