Variable frictional feedback device for a digital crown of an electronic watch
An electronic device, such as a watch, has a variable friction mechanism for providing variable frictional feedback as an input mechanism, such as a crown, is rotated. The variable frictional feedback may correspond to operational states, events, or other conditions at the electronic watch. The variable frictional feedback may be provided by changing a frictional force between the crown and the variable friction mechanism. The variable friction mechanism may include a friction element adapted to contact a shaft of the crown and an actuator adapted to change a frictional force between the friction element and the shaft.
1. An electronic watch, comprising:
an enclosure defining an opening;
a processing unit positioned within the enclosure;
a crown operably coupled to the processing unit and configured to receive a rotational input, the crown comprising:
a user-rotatable crown body; and
a shaft assembly coupled to the user-rotatable crown body and extending through the opening;
a rotation sensor positioned within the enclosure and operably coupled to the processing unit, the rotation sensor configured to detect the rotational input; and
a variable friction mechanism operably coupled to the processing unit and configured to produce a variable frictional feedback as the crown is rotated by the rotational input, the variable friction mechanism comprising:
a friction element positioned at least partially around a peripheral surface of the shaft assembly; and
an actuator configured to change a friction between the friction element and the peripheral surface of the shaft assembly to produce the variable frictional feedback.
2. The electronic watch of claim 1 , wherein the processing unit is configured to:
determine a characteristic of the rotational input;
determine an amount of the variable frictional feedback to be produced based, at least in part, on the determined characteristic; and
output a signal to the variable friction mechanism causing the variable friction mechanism to produce the variable frictional feedback.
3. The electronic watch of claim 1 , wherein the electronic watch further comprises a touch-sensitive display operably coupled to the processing unit and at least partially surrounded by the enclosure, the touch-sensitive display configured to:
receive a touch input; and
provide a graphical output that is responsive to each of:
the touch input; and
the rotational input.
4. The electronic watch of claim 1 , wherein producing the variable frictional feedback comprises varying a resistive torque associated with rotating the crown.
5. The electronic watch of claim 4 , wherein the variable friction mechanism is configured to:
in response to receiving a first signal from the processing unit, increase the resistive torque for a first portion of the rotational input; and
in response to receiving a second signal from the processing unit, decrease the resistive torque for a second portion of the rotational input.
6. The electronic watch of claim 4 , wherein the variable friction mechanism is configured to alternately increase and decrease the resistive torque in accordance with at least one of:
a predetermined number of times per complete rotation of the crown; or
at predetermined intervals of time.
7. The electronic watch of claim 4 , wherein:
the electronic watch has a first graphical output mode and a second graphical output mode; and
the variable friction mechanism is configured to:
in the first graphical output mode, alternately increase and decrease the resistive torque in accordance with at least one of:
a first predetermined number of times per complete rotation of the crown; or
at first predetermined intervals of time having a first duration; and
in the second graphical output mode, alternately increase and decrease the resistive torque in accordance with at least one of:
a second predetermined number of times per complete rotation of the crown; or
at second predetermined intervals of time having a second duration.
8. The electronic watch of claim 1 , wherein the friction element is an elastomeric polymer material.
9. The electronic watch of claim 1 , wherein:
the actuator is configured to apply a first force to the friction element, thereby changing a shape of the friction element; and
the change in the shape of the friction element increases a second force applied by the friction element on the peripheral surface of the shaft assembly.
10. An electronic device, comprising:
an enclosure;
a processing unit positioned within the enclosure;
a touch-sensitive display operably coupled to the processing unit and positioned at least partially within the enclosure, the touch-sensitive display configured to receive a touch input and provide a graphical output;
a crown configured to receive a rotational input and defining a shaft assembly extending through an opening of the enclosure; and
a variable friction mechanism configured to provide a variable frictional feedback at the crown in response to a signal received from the processing unit, the variable friction mechanism comprising:
a friction element positioned at least partially around a peripheral surface of the shaft assembly; and
an actuator configured to change a friction between the friction element and the peripheral surface of the shaft assembly to produce the variable frictional feedback;
wherein:
the variable frictional feedback corresponds to at least one of:
the graphical output; or
the rotational input.
11. The electronic device of claim 10 , wherein:
the graphical output comprises a first selectable element and a second selectable element;
in a first state, the first selectable element is selected;
in a second state, the second selectable element is selected;
the rotational input causes a transition from the first state to the second state; and
the variable frictional feedback is produced during the transition from the first state to the second state.
12. The electronic device of claim 10 , wherein:
the variable frictional feedback is a first variable frictional feedback;
the signal is a first signal;
in a first mode, the variable friction mechanism is configured to provide the first variable frictional feedback in response to the signal received from the processing unit; and
in a second mode, the variable friction mechanism is configured to provide a second variable frictional feedback in response to a second signal received from the processing unit.
13. The electronic device of claim 12 , wherein:
in the first mode:
the graphical output comprises a first scrollable list of graphical elements, the first scrollable list having a first length; and
the variable friction mechanism exerts a first force on the crown; and
in the second mode:
the graphical output comprises a second scrollable list of graphical elements, the second scrollable list having a second length shorter than the first length; and
the variable friction mechanism exerts a second force greater than the first force on the crown.
14. The electronic device of claim 12 , wherein:
the graphical output comprises a scrollable list of selectable elements;
in the first mode:
a first selectable element that is not a last item of the scrollable list is selected; and
the variable friction mechanism allows rotation of the crown in a first direction and a second direction; and
in the second mode:
a second selectable element that is the last item of the scrollable list is selected; and
the variable friction mechanism prevents the crown from being rotated in at least one of the first direction or the second direction.
15. The electronic device of claim 10 , wherein providing the variable frictional feedback comprises:
continuously increasing a frictional force between the variable friction mechanism and the crown as the crown is rotated in a first direction; and
continuously decreasing the frictional force between the variable friction mechanism and the crown as the crown is rotated in a second direction.
16. The electronic device of claim 15 , wherein:
rotating the crown in the first direction increases at least one of:
a volume level;
a display brightness; or
a zoom; and
rotating the crown in the second direction decreases the at least one of:
the volume level;
the display brightness; or
the zoom.
17. A method for producing variable frictional feedback as a crown of an electronic watch is rotated, the method comprising:
detecting a rotational input at the crown;
determining, by a processing unit of the electronic watch, a variable frictional feedback to produce as the crown rotates;
outputting, by the processing unit, a signal to provide the variable frictional feedback; and
varying, by a variable friction mechanism, a resistive torque associated with rotating the crown to produce the variable frictional feedback, the varying comprising:
causing an actuator to vary a force applied to a friction element that at least partially surrounds a peripheral surface of a shaft assembly of the crown, thereby varying a friction between the friction element and the peripheral surface of the shaft assembly.
18. The method of claim 17 , wherein varying the friction comprises at least one of continuously increasing or decreasing the friction as the crown is rotated.
19. The method of claim 17 , wherein determining the variable frictional feedback corresponding to the detected rotational input comprises detecting at least one of:
an input received by the electronic watch;
an output provided by the electronic watch; or
a user interface command.
20. The method of claim 17 , wherein:
the force applied to the friction element is a first force and acts in a first direction; and
the first force causes the friction element to apply a second force on the peripheral surface of the surface of the shaft assembly, the second force acting in a second direction different from the first direction.