Variable-conductance sensor

• US 5,999,084 A
• Filed: 06/29/1998
• Issued: 12/07/1999
• Est. Priority Date: 06/29/1998
• Status: Expired due to Fees

• Current Assignee: Anascape, Ltd.
• Original Assignee: Brad A. Armstrong
• Inventors: Armstrong, Brad A.
• Primary Examiner(s): Gellner, Michael L.
• Assistant Examiner(s): EASTHOM, KARL D
• Application Number:
  US09/106,825
• Time in Patent Office: 526 Days
• Field of Search: 338/2, 338/5, 338/47, 338/92, 338/93, 338/96, 338/99, 338/112, 338/114, 73/862.629, 73/862.637, 200/406, 200/511, 200/516, 29/613, 29/621.1, 29/622
• US Class Current: 338/114
• CPC Class Codes: H01C 10/106 on resistive material dispersed in an elastic material H01C10/103 and H01C10/12 take precedence; for electric switches H01H1/029
• CPC Class Codes: H01H 13/48 using buckling of disc springs
• CPC Class Codes: H01H 13/785 characterised by the material of the contacts, e.g. conductive polymers
• CPC Class Codes: H01H 2201/036 Variable resistance
• CPC Class Codes: Y10T 29/49087 with envelope or housing

Abstract

A sensor having a housing; two highly conductive elements fixed in-part within the housing and in-part exposed external of the housing; the conductive elements separated from one another within the housing in a normally open arrangement. A resilient dome-cap is positioned within the housing, and in some embodiments is conductive and in constant contact with one of the conductive elements, and in other embodiments the dome-cap need not be conductive. A depressible actuator is movably retained by the housing with a portion thereof external of the housing to be accessible for depressive force to be applied thereto by a mechanical device or human finger/thumb. The actuator also includes a portion positioned to allow depressive force applied thereto to be applied to the dome-cap. Pressure-sensitive variable-conductance material is contained within the housing and electrically positioned as a variably conductive element in a current flow path between the two conductive elements. Depression of the actuator causes the dome-cap to bow downward, causing a user discernable tactile sensation indicating actuation of the sensor, and transferring force through the dome-cap into the pressure-sensitive variable-conductance material for providing variable electrical flow between the two conductive elements dependant upon the applied pressure. The resilient dome-cap returns to a raised position and the flow path is again rendered open when the actuator is no longer depressed. Methods of manufacturing the variable electrical output tactile-feedback sensor are also disclosed.

Claims

1. A pressure-sensitive variable-conductance analog sensor with tactile feedback, comprising;

a housing;

at least two conductive elements fixed to said housing and in-part within said housing;

a depressible actuator retained by said housing and in-part exposed external to said housing;

a resilient snap-through dome-cap positioned within said housing and depressible with force from said actuator applied to said dome-cap to cause said dome-cap to snap-through and create a tactile feedback;

pressure-sensitive variable-conductance material within said housing and positioned as a variably conductive element electrically between said two conductive elements, and further positioned for receiving force applied to said dome-cap, whereby electrical conductivity of said pressure-sensitive variable-conductance material is altered relative to received force and electrical output of said sensor is variable.

2. A pressure-sensitive variable-conductance analog sensor with tactile feedback in accordance with claim 1 wherein said two conductive elements are of high and relatively constant conductivity.

3. A pressure-sensitive variable-conductance analog sensor with tactile feedback in accordance with claim 2 wherein said pressure-sensitive variable-conductance material is variable in terms of electrical resistivity, the electrical resistivity of said pressure-sensitive variable-conductance material lowering with received force thereon.

4. A pressure-sensitive variable-conductance analog sensor with tactile feedback in accordance with claim 3 wherein said housing is formed of non-conductive plastics.

5. An improved pressure-sensitive variable-conductance analog sensor of the type having at least two electrically conductive elements operationally connected to pressure-sensitive variable-conductance material;

a depressible actuator retained relative to said pressure-sensitive variable-conductance material;

said actuator depressible toward said pressure-sensitive variable-conductance material for transferring force into said pressure-sensitive variable-conductance material;

wherein the improvement comprises;

a resilient snap-through dome-cap positioned to provide tactile feedback to a user upon actuation of said pressure-sensitive variable-conductance material.

6. An improved pressure-sensitive variable-conductance analog sensor in accordance with claim 5 wherein said snap-through dome-cap is positioned between said actuator and said pressure-sensitive variable-conductance material.

7. An improved momentary-On snap-through switch package of the type having a housing;

at least two conductive elements fixed to said housing and in-part within said housing and at least in-part exposed external of said housing;

a resilient snap-through dome-cap positioned within said housing;

a depressible actuator retained by said housing and in-part exposed external to said housing;

said actuator depressible for depressing said dome-cap and creating a highly conductive electrical path between said two conductive elements;

wherein the improvement comprises;

pressure-sensitive analog variable-conductance material within said housing and positioned for creating a variably conductive electrical path between said two conductive elements upon variable depression of said dome-cap.

8. A pressure-sensitive analog variable-conductance sensor with tactile feedback in accordance with claim 7 wherein said pressure-sensitive variable-conductance material is variable in terms of electrical resistivity, the electrical resistivity of said pressure-sensitive analog variable-conductance material lowering with received force thereon.

9. A method of manufacturing a pressure-sensitive analog variable-conductance sensor with tactile feedback, comprising the steps of:

a) forming two conductive elements;

b) forming a housing engaging said two conductive elements, and leaving a portion of said two conductive elements exposed external of said housing;

c) installing pressure-sensitive analog variable-conductance material positioned as a variably conductive element electrically between said two conductive elements;

d) installing a resilient tactile feedback dome-cap positioned within said housing and operationally associated with said pressure-sensitive variable-conductance material;

e) installing an actuator in-part within said housing and in-part exposed external of said housing and positioned for transferring externally applied force onto said actuator through said dome-cap and onto said pressure-sensitive variable-conductance material.

10. An improved method of manufacturing a sensor of the type comprising the steps of:

forming two conductive elements;

forming a housing engaging said two conductive elements, and leaving a portion of said two conductive elements exposed external of said housing;

installing an actuator in-part within said housing and in-part exposed external of said housing;

installing a resilient snap-through dome-cap positioned within said housing;

wherein the improvement comprises the step of;

installing pressure-sensitive analog variable-conductance material positioned as a variably conductive element electrically between said two conductive elements.

11. An improved method of manufacturing a pressure-sensitive analog variable-conductance sensor, comprising the steps of:

forming two conductive elements;

locating pressure-sensitive variable-conductance material positioned as a variably conductive element electrically between said two conductive elements;

positioning an actuator for transferring externally applied force onto said pressure-sensitive analog variable-conductance material;

wherein the improvement comprises the step of;

positioning a resilient tactile feedback dome-cap operationally associated with said pressure-sensitive variable-conductance material.