Sensor electrode for capacitive sensor device in a keyboard having a width decreasing towards its center

• US 10,461,745 B2
• Filed: 09/21/2015
• Issued: 10/29/2019
• Est. Priority Date: 02/27/2013
• Status: Active Grant

• Current Assignee: Microchip Technology Germany GmbH (Microchip Technology Incorporated)
• Original Assignee: Microchip Technology Germany GmbH (Microchip Technology Incorporated)
• Inventors: Heim, Axel
• Primary Examiner(s): Hopkins, Brandi N
• Application Number:
  US14/860,270
• Publication Number:
  US 20160013790A1
• Time in Patent Office: 1,499 Days
• CPC Class Codes: H01H 1/06 characterised by the shape or structure of the contact-making surface, e.g. grooved
• CPC Class Codes: H01H 11/04 of switch contacts
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 17/98 having a plurality of control members, e.g. keyboard
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes
• CPC Class Codes: H03K 2217/96078 Sensor being a wire or a strip, e.g. used in automobile door handles or bumpers
• CPC Class Codes: H05K 1/0296 Conductive pattern lay-out details not covered by sub groups H05K1/02 - H05K1/0295 H05K1/11 takes precedence; lay-out adapted to mounted component configuration H05K1/18
• CPC Class Codes: Y10T 29/49105 Switch making

Abstract

A sensor electrode (SE) for a capacitive sensor device is designed such that the width of the sensor electrode decreases towards the center such that the capacity between the sensor electrode and an object (F) with constant distance between the sensor electrode and the object (F) substantially is equal in size for each position of the object (F) relative to the sensor electrode along a longitudinal axis of the sensor electrode. The sensor electrode may consist of a plurality of segments arranged in a strip with decreasing width towards the center of the electrode.

Claims

1. A sensor electrode (SE) for a capacitive sensor device, comprising a plurality of sensor segments separated by insulating spaces and distributed along a line, wherein each sensor segment has a width extending along the line, wherein the width of a sensor segment arranged at a longitudinal center area of the line is smaller than the width of a sensor segment arranged at a beginning or an end of the line defining the sensor electrode, wherein the width of each sensor element is chosen such that the capacity between the sensor electrode and an object (F) with constant distance between the sensor electrode and the object (F) substantially is equal in size for each position of the object (F) relative to the sensor electrode along a longitudinal axis of the sensor electrode and wherein the plurality of sensor segments are electrically short-circuited to one another.

2. A keyboard comprising keys and a plurality of sensor electrodes according to claim 1 wherein each sensor electrode is arranged between a plurality of said keys and surrounds at least one key.

3. The keyboard of claim 2, wherein each sensor electrode has a strip-type shape.

4. The keyboard of claim 2, wherein each sensor electrode has a rectangular shape.

5. The keyboard according to claim 2, further comprising a plurality of keys being separate from said at least one sensor electrode.

6. The keyboard according to claim 5, wherein the at least one sensor electrode is configured to provide for a touchless proximity detection.

7. The keyboard according to claim 2, further comprising a plurality of keys wherein the at least one sensor electrode is arranged between the plurality of keys.

8. A keyboard comprising keys and at least one sensor electrode according to claim 1.

9. A keyboard comprising keys and at least one sensor electrode being arranged between a plurality of said keys and comprising a rectangular shaped electrode having recesses in an inner region of the sensor electrode segmenting said sensor electrode wherein sensor segments of the sensor electrode are electrically short-circuited to one another, wherein recesses in said electrode are formed such that a width of a recess in a center region of the sensor electrode is greater than a width of a recess adjacent an edge of the electrode.

10. The keyboard according to claim 9, wherein the recesses are designed to form separate electrode segments in an inner area of the sensor electrode.

11. The keyboard according to claim 10, wherein the recesses are arranged inside an inner area of the sensor electrode comprising a first and second horizontal recess adjacent a top and bottom edge of the sensor electrode, respectively and a first and second vertical recess adjacent a left and right edge of the sensor electrode, respectively.

12. The keyboard according to claim 9, wherein sensor values that can be obtained from said sensor electrode substantially remain constant at substantially constant distance between finger and sensor electrode independent of a position of the finger relative to the sensor electrode.

13. The keyboard according to claim 9, wherein the recesses are arranged in an area between adjacent keys.

14. The keyboard according to claim 9, wherein the recesses are designed to form a plurality of electrode segments in an inner area of the sensor electrode.

15. The keyboard according to claim 14, wherein the recesses comprise a first and second horizontal recess adjacent a top and bottom edge of the sensor electrode, respectively and a first and second vertical recess adjacent a left and right edge of the sensor electrode, respectively.

16. The keyboard according to claim 9, wherein sensor values that can be obtained from said sensor electrode substantially remain constant at substantially constant distance between finger and sensor electrode independent of the position of the finger relative to the sensor electrode.

17. The keyboard according to claim 9, further comprising a plurality of keys being separate from said at least one sensor electrode.

18. The keyboard according to claim 17, wherein the at least one sensor electrode is configured to provide for a touchless proximity detection.

19. The keyboard according to claim 9, further comprising a plurality of keys wherein the at least one sensor electrode is arranged between the plurality of keys.