Device for varying capacitance

• US 7,696,444 B2
• Filed: 01/25/2007
• Issued: 04/13/2010
• Est. Priority Date: 01/26/2006
• Status: Active Grant

• Current Assignee: Hanvon Pentech Co., Ltd.
• Original Assignee: Hanwang Technology Co Limited (Hanwang Technology)
• Inventors: Zhao, Liang, Song, Bojun, Liu, Yingjian, Wang, Honggang
• Primary Examiner(s): Hjerpe; Richard
• Assistant Examiner(s): Okebato; Sahlu
• Application Number:
  US11/657,724
• Publication Number:
  US 20070180923A1
• Time in Patent Office: 1,174 Days
• Field of Search: 178 1901- 1907, 345/179
• US Class Current: 178/19.03
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: H01G 5/011 Electrodes
• CPC Class Codes: H01G 5/0136 with movable electrodes
• CPC Class Codes: H01G 5/014 Housing; Encapsulation

Abstract

Disclosed is a device for varying capacitance which pertains to the field of application of electronic devices and components. The technical essentials of the present invention lie in that: two dielectrics are disposed in parallel with an isolation layer interposed therebetween; the two dielectrics each are connected to an electrode at the same one end face thereof; the other end face of each of the two dielectrics is provided with an elastic conductive pad; a gasket is provided between the two dielectrics and the elastic conductive pads. The relative position and compressed area between the elastic conductive pads and the dielectrics vary according to the magnitude of the external force so that the capacitance between the electrodes of the dielectrics is varied accordingly within a certain range. Therefore, once the value and the variation of the capacitance between the electrodes are measured, the magnitude and the status of the external force which brings about the variation of the capacitance can be obtained. The device of the present invention has a simple structure and high sensitivity. Also, it has a definite zero initial value and a maximum value of the capacitance, and therefore is easy for handing and measurement.

Claims

1. A device for varying capacitance, comprising:

a first dielectric (54) and a second dielectric (55), the first dielectric (54) and the second dielectric (55) being arranged in parallel and spaced apart from each other to form an isolation layer (58) therebetween;

a first electrode (56) and a second electrode (57), the first electrode (56) and the second electrode are connected to the first dielectric (54) and the second dielectric (55) at the same one end face of the first dielectric (54) and the second dielectric (55), respectively,

an elastic conductive pad (52) being disposed at the other end face opposite to the one end face; and

a gasket (53) being disposed between the first dielectric (54) and the second dielectric (55) and the elastic conductive pad (52).

2. The device according to claim 1, further comprising:

a contact probe (51), the contact probe (51) being configured to apply an acting force on the elastic conductive pad (52) when an external force is applied on it.

3. The device according to claim 1, wherein:

the first dielectric (54) and the second dielectric (55) are disposed in a mirror-symmetrical manner.

4. The device according to claim 1, further comprising:

a housing (59), wherein the first dielectric (54) and the second dielectric (55) being disposed in the housing (59) abutting against the inner wall of the housing.

5. The device according to claim 1, wherein:

the shape of the first electrode (56) and the second electrode (57) is substantially identical with that of the first dielectric (54) and the second dielectric (55) respectively, and the first electrode (56) and the second electrode (57) being tightly attached to the same one end face of the first dielectric (54) and the second dielectric (55) respectively.

6. The device according to claim 1, wherein:

the isolation layer (58) is filled with material of low dielectric constant.

7. The device according to claim 1, wherein:

the isolation layer (58) is filled with air.

8. The device according to claim 1, wherein:

the elastic conductive pad (52) is made of elastic conductive material.

9. The device according to claim 1, wherein:

the gasket (53) is made of a material of low dielectric constant.

10. The device according to claim 1, wherein:

the gasket (53) is configured to have an annular shape.

11. The device according to claim 2, wherein:

the contact probe (51) has an end face configured to have a convex shape which is higher in the middle and lower in the periphery.

12. The device according to claim 2, wherein:

an elastic conductive body (522) is further disposed between the contact probe (51) and the elastic conductive pad (52).

13. The device according to claim 2, wherein:

an elastic conductive body (533) is further disposed between the elastic conductive pad (52) and the gasket (53).

14. The device according to claim 1, wherein:

the first dielectric (54) and the second dielectric (55) are made of a material of relatively high dielectric constant.

15. The device according to claim 3, wherein:

the first dielectric (54) and the second dielectric (55) constitute a circular shape.

16. The device according to claim 11, wherein:

the convex shape of the contact probe (51) is a conical shape or a shape of spherical cap.

17. A handwriting inputting device, comprising the device for varying capacitance according to claim 1.

18. The handwriting inputting device according to claim 17, further comprising:

a contact probe (51), the contact probe (51) being configured to apply an acting force on the elastic conductive pad (52) when an external force is applied on it.

19. The handwriting inputting device according to claim 17, wherein:

the first dielectric (54) and the second dielectric 955) are disposed in a mirror-symmetrical manner.

20. The handwriting inputting device according to claim 17, further comprising:

A housing (59), wherein the first dielectric (54) and the second dielectric (55) being disposed in the housing (59) abutting the inner wall of the housing.