Track pad with force sensing and haptic features
AssigneeAzoteq Holdings Limited
InventorsFrederick Johannes Bruwer, Dieter Sydney-Charles Mellet
Life of this patent
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Abstract
A capacitive track pad using force sensing to determine the approximate position of touch on the track pad and to use this position as a check against a capacitive touch determined position in order to disqualify potential noise generated signals. The position resolved from the inductive force sensing measurements can also be used to assist in generating a uniform haptic experience for the user. The force sensing measurements are also used to determine if the threshold for a “click” has been met.
Claims22
Apparatus for determining the position and level of a force exerted by a user on a capacitive sensing track pad which has four corners, the apparatus including at or near each corner a respective inductive force sensor which produces a respective signal which is dependent on the level of force measured by such sensor, and a processor, responsive to said signals, which is configured to determine said position and level of force exerted on the track pad by using the information from all the inductive force sensors, the apparatus further including at least one haptic generator responsive to said signals, whereby a driving force of the at least one haptic generator is adjusted according to said position of force to achieve a more uniform haptic sensation anywhere on the track pad, wherein the processor is configured, when said capacitive track pad measurements detect multiple contact points on the track pad, to vary the magnitude of said force level which is required for a “click” event to be recognized.
Apparatus for determining the position and level of a force exerted by a user on a capacitive sensing track pad which has four corners, the apparatus including at or near each corner a respective inductive force sensor which produces a respective signal which is dependent on the level of force measured by such sensor, and a processor, responsive to said signals, which is configured to determine said position and level of force exerted on the track pad by using the information from all the inductive force sensors, the apparatus further including at least one haptic generator responsive to said signals, whereby a driving force of the at least one haptic generator is adjusted according to said position of force to achieve a more uniform haptic sensation anywhere on the track pad, wherein each inductive force sensor comprises an inductor with a core and an interfering member which is movable into the core, in response to force applied to the track pad, in order to affect the inductance of the inductor.
A method of using inductive force sensors in or near at least four corners of a capacitive sensing track pad, wherein the force sensing measurements of the inductive sensors are used to resolve an approximate position and level of force exerted by a user on said track pad, the method further comprising the step of using adaptive software to automatically calibrate for mechanical variations that happen over time, said calibrations based on correlation between information relating to said force sensing measurements and information relating to capacitive track pad measurements.
Dependencies are inferred from the claim text.