Force sensing touchpad
AssigneeSynaptics Incorporated
InventorsJosef C. Frisch, Gregory E. Leyh, John C. Platt, Timothy P. Allen, Richard R. Schediwy, Federico Faggin
Life of this patent
Estimating the term…
Abstract
A force sensing touchpad comprises a substantially rigid touch surface; a substantially rigid frame; a plurality of spring structures formed integrally with the touch surface and mechanically connected to the reference frame; and a circuit for deriving force information from capacitances proportional to the distances between predetermined portions of the touch surface and portions of the frame in response to a force applied to the touch surfaces.
Claims21
A force sensing touchpad comprising:
- a substantially rigid touch surface, force to be sensed being applied thereto;
- a substantially rigid frame member;
- a plurality of spring means disposed between said touch surface and said frame member, said spring means mechanically connected to said touch surface and said frame member;
- and
- a plurality of variable capacitors associated with said touchpad, each variable capacitor having a capacitance which is a monotonic function of the distance between selected portions of said touch surface and said frame member, each said variable capacitor having sense outputs.
A force sensing touchpad comprising:
- a substantially rigid touch surface having a rectangular shape;
- a substantially rigid frame member;
- a plurality of spring means disposed between said touch surface and said frame member, said spring means mechanically connected to said touch surface and said frame member;
- and
- a plurality of variable capacitors associated with said touchpad, each variable capacitor having a capacitance which is a monotonic function of the distance between selected portions of said touch surface and said frame member, each said variable capacitor having sense outputs,
- wherein said plurality of variable capacitors comprises four variable capacitors, each of said variable capacitors located symmetrically at corners of a rectangle centered on said touch surface.
A method for sensing the magnitude and point of application of a force applied to a touchpad comprising the steps of:
- providing a substantially rigid touch surface, force to be sensed being applied thereto;
- providing a substantially rigid frame member;
- providing a plurality of spring means disposed between said touch surface and said frame member, said spring means mechanically connected to said touch surface and said frame member;
- providing a plurality of variable capacitors associated with said touchpad, each variable capacitor having a capacitance which is a monotonic function of the distance between selected portions of said touch surface and said frame member, each said variable capacitor having sense outputs;
- providing force determining means coupled to said sense outputs of said plurality of variable capacitors to determine the magnitude and location of a force applied to said touch surface.
Dependencies are inferred from the claim text.