Retractable and/or variable depression force key assemblies and methods for using the same

Patent metadata

Field	Value
Publication number	US-10574233-B2
Application number	US-201715418232-A
Country	US
Kind code	B2
Filing date	Jan 27, 2017
Priority date	Jan 27, 2017
Publication date	Feb 25, 2020
Grant date	Feb 25, 2020

Abstract

Key assemblies are disclosed herein that are retractable and/or that present a variable key assembly depression force to a user. In one example, one or more key assemblies may be provided that each employ one or more electro-permanent magnets (EPMs) together with permanent magnet and/or magnetically permeable (e.g., ferromagnetic) key assembly components to control key retraction and extension, and/or to control peak depression force (e.g., typing force) required to depress and displace a key assembly from an extended position to a lower position that causes the key assembly to produce a digital or analog output signal.

First claim

What is claimed is:

1. A key assembly, comprising:
at least one key assembly component comprising at least one permanent magnet material or magnetically permeable material and coupled to move toward and away from a base; and
at least one electro-permanent magnet (EPM) coupled in fixed relationship to the base, the EPM being positioned to emit an external magnetic field that acts on the permanent magnet material or magnetically permeable material of the key assembly component;
where the at least one EPM comprises first and second permanent magnets having different intrinsic coercivities disposed side by side with their polarities in parallel direction, a first end of the first permanent magnet disposed adjacent a first end of the second permanent magnet and a second end of the first permanent magnet disposed adjacent a second end of the second permanent magnet; a first shunt of the magnetically permeable material coupled between the first end of the first permanent magnet and the first end of the second permanent magnet; a second shunt of the magnetically permeable material coupled between the second end of the first permanent magnet and the second end of the second permanent magnet; and a conductive coil wrapped around at least one of the first and second permanent magnets and receiving a temporary current pulse of a first polarity to reverse a direction of a magnetic polarity of the at least one of the first and second permanent magnets from a first magnetic polarity to a second magnetic polarity that is held after the temporary current pulse ends with no further application of electrical current and until another temporary current pulse of a second opposite polarity is received by the coil to reverse the magnetic polarity of the at least one of the first and second permanent magnets.

2. The key assembly of claim 1 , where the at least one EPM comprises multiple EPMs; where the key assembly component comprises a keycap coupled to move with the key assembly component relative to the base; where the base comprises a baseplate; where the key assembly component comprises opposing first and second angled support arms, the first angled support arm being coupled to the baseplate by a first fulcrum between a first portion and a second portion of the first angled support arm, and the second angled support arm being coupled to the baseplate by a second fulcrum between a first portion and a second portion of the second angled support arm, the first and second fulcrums being spaced apart; where the first portion of each of the first and second angled support arms is coupled to the keycap; and where the permanent magnet material or magnetically permeable material of the key assembly is fixedly coupled to the opposing first and second angled support arms so that the multiple EPMs are positioned to emit the external magnetic field that acts on the permanent magnet material or magnetically permeable material on same side of the first fulcrum.

3. The key assembly of claim 1 , where the key assembly component comprises a keycap coupled to move with the key assembly component relative to the base; where the base comprises a baseplate; where the key assembly component comprises opposing first and second angled support arms, the first angled support arm being coupled to the baseplate by a first fulcrum between a first portion and a second portion of the first angled support arm, and the second angled support arm being coupled to the baseplate by a second fulcrum between a first portion and a second portion of the second angled support arm, the first and second fulcrums being spaced apart; where the first portion of each of the first and second angled support arms is coupled to the keycap; and where the permanent magnet material or magnetically permeable material of the key assembly is fixedly coupled to at least one of the opposing first and second angled support arms so that the EPM is positioned to emit the external magnetic field that acts on the permanent magnet material or magnetically permeable material on same side of the first fulcrum.

4. The key assembly of claim 3 , where the second portions of the first and second angled support arms are coupled together in movable relationship between the first and second fulcrums; and where the permanent magnet material or magnetically permeable material is coupled to the second portion of the at least one of the opposing first and second angled support arms so that the EPM is positioned to emit the external magnetic field that acts on the permanent magnet material or magnetically permeable material.

5. The key assembly of claim 3 , where the second portions of the opposing first and second angled support arms are coupled together in movable relationship between the first and second fulcrums; where the permanent magnet material or magnetically permeable material comprises a first magnetically permeable material having a first end fixedly coupled to the first portion of the opposing first angled support arm, and a second end that extends past the first fulcrum so that the first fulcrum is positioned between the first end of the first magnetically permeable material and the second end of the first magnetically permeable material; and where the at least one EPM is positioned to emit the external magnetic field that acts on one of the first end or second end of the first magnetically permeable material.

6. The key assembly of claim 5 , further comprising at least two EPMs coupled in fixed relationship to the baseplate, a first one of the two EPMs being positioned to emit a first external magnetic field that acts on the first end of the first magnetically permeable material; and a second one of the two EPMs being positioned to emit a second external magnetic field that acts on the second end of the first magnetically permeable material.

7. The key assembly of claim 5 , further comprising a resilient material coupled to bias the key assembly component either toward or away from the baseplate; and where the at least one EPM is positioned to emit the external magnetic field that acts on the second end of the first magnetically permeable material.

8. The key assembly of claim 1 , where the key assembly component is either a button for a peripheral device or is a keyboard key of a keyboard matrix for an information handling system that includes multiple key assemblies.

9. A method, comprising:
moving at least one key assembly component toward a base in response to a depression force applied to the key assembly component by a user, the key assembly component comprising at least one permanent magnet material or magnetically permeable material; and
applying at least one temporary current pulse to at least one electro-permanent magnet (EPM) coupled in fixed relationship to the base;
where the at least one temporary current pulse is applied to establish a state of an external magnetic field of the EPM that acts on the permanent magnet material or magnetically permeable material of the key assembly component, the established state of the external magnetic field of the EPM being maintained after the temporary current pulse has ended with no further application of electrical current of the temporary current pulse;
where the applying of the at least one temporary current pulse to the at least one EPM coupled in the fixed relationship to the base comprises a first applying the at least one temporary current pulse with an amplitude selected to establish a controlled strength state of the external magnetic field of the EPM that acts on the permanent magnet material or magnetically permeable material of the key assembly component to produce a selected peak key depression force required to depress the key assembly component from an extended position towa

Assignees

• Dell Products Lp

Inventors

• Casparian Mark A
• Olmsted Joe A
• Grossmann Philip J
• Morrison Jason
• Azor Frank C

Classifications

• H03K2217/96023

  Details of electro-mechanic connections between different elements, e.g.: sensing plate and integrated circuit containing electronics · CPC title

• H01H2227/034

  Regulation of operating force · CPC title

• H01F7/204

  Circuits for energising or de-energising · CPC title

• H03K17/972 Primary

  having a plurality of control members, e.g. keyboard · CPC title

• H01F7/0273

  Magnetic circuits with PM for magnetic field generation · CPC title