Abstract: An optically transparent force sensor that may compensate for environmental effects, including, for example, variations in temperature of the device or the surroundings. In some examples, two force-sensitive layers are separated by a compliant layer. The relative electrical response of the two force-sensitive layers may be used to compute an estimate of the force of a touch that reduces the effect of variations in temperature. In some examples, piezoelectric films having anisotropic strain properties are used to reduce the effects of temperature.

Abstract: A haptic feedback assembly includes interconnections for mechanically and electrically securing a haptic actuator in a track pad assembly so as to securely and efficiently provide haptic feedback to a user.

Abstract: An electronic device including a processor, a display screen in communication with the processor, a track pad in communication with the processor including a movable surface that is selectively movable in at least one direction to provide feedback to a user, and a feedback system in communication with the processor including a feedback sensor. The feedback sensor determines a movement characteristic of the movable surface and the processor selectively adjusts at least one setting of the track pad based on the movement characteristic.

Abstract: A haptic electromagnetic actuator for track pad is provided. The actuator includes an array of electromagnets with alternating South and North poles on a first end, each magnet comprising a metal core and an electrical wire around the metal core. The array of magnets is coupled to a base plate on a second end opposite to the first end. The actuator also includes an attraction plate at a distance from the first end of the array of the magnets such that the attraction plate moves toward the magnets when an electrical current flows through the electrical wire around the metal core and moves away from the magnets when the current becomes zero. The array of magnets is configured to form a uniform gap from the attraction plate.