Patent ID: 11942285
Assignee: APPLE INC.
Field: Measurement (Instruments)
Classification: CPC H  G  Y | IPC G  H

Claim 0:
1. A keyboard, comprising:
a base;
a keycap configured to translate relative to the base between a first position, a second position, and a third position; and
a membrane layer positioned between the keycap and the base, the membrane layer including:
a flexible sheet;
a first piezoresistor positioned on the flexible sheet between the keycap and the base and having a variable first resistance;
a second piezoresistor positioned on the flexible sheet between the keycap and the base and having a variable second resistance; and
a conductor connecting the first piezoresistor to the second piezoresistor;
wherein, in response to movement of the keycap between the first position and the second position, a voltage measured at the conductor, and influenced by a ratio of the variable first resistance and the variable second resistance, is less than a predetermined threshold value; and
wherein, in response to movement of the keycap between the second position and the third position, the voltage measured at the conductor, and influenced by the ratio of the variable first resistance to the variable second resistance, is greater than the predetermined threshold value due to deformation of at least the first piezoresistor.