Haptic button with SMA
Broadly speaking, embodiments of the present techniques provide haptic button assemblies in which the haptic button has a low profile while still providing a satisfying tactile response or sensation to a user. Advantageously, the haptic button assemblies may have a profile that, for example, enables the assembly to be incorporated into the free space along an edge of a portable computing device. The haptic assemblies may, for example, be arranged to move the button perpendicularly with respect to the edge of the device.
1. An apparatus comprising:
a static component;
a moveable component that is moveable along a first axis relative to the static component;
at least one assembly arranged to move the moveable component, the assembly comprising:
at least one intermediate moveable element moveable along a second axis that is inclined relative to the first axis or perpendicular to the first axis, wherein the at least one intermediate moveable element is arranged in contact with the moveable component so as to drive movement of the moveable component; and
at least one shape memory alloy (SMA) actuator wire coupled to the at least one intermediate moveable element and arranged to, on contraction, drive movement of the intermediate moveable component.
2. The apparatus of claim 1 , comprising a bearing provided between the intermediate moveable element and the moveable component and arranged to move the moveable component along the first axis when the intermediate moveable element moves along the second axis.
3. The apparatus of claim 2 , wherein the bearing comprises at least one ramp.
4. The apparatus of claim 3 , wherein the bearing further comprises at least one ball bearing arranged to roll along the at least one ramp.
5. The apparatus of claim 3 , wherein the at least one ramp is provided by an inclined surface of the intermediate moveable element and/or of the static component.
6. The apparatus of claim 3 , wherein the at least one ramp is a localised ramp provided on a surface of the intermediate moveable element and/or on the surface of the static component.
7. The apparatus of claim 3 , wherein the at least one ramp has a constant gradient.
8. The apparatus of claim 3 , wherein the at least one ramp has a variable, non-constant gradient.
9. The apparatus of claim 1 , comprising a bearing provided between the intermediate moveable element and the static component and arranged to bear movement of the intermediate moveable element along the second axis.
10. The apparatus of claim 9 , wherein the bearing comprises at least one ramp.
11. The apparatus of claim 10 , comprising at least one ball bearing arranged to roll along the at least one ramp.
12. The apparatus of claim 10 , wherein the at least one ramp has a constant gradient.
13. The apparatus of claim 10 , wherein the at least one ramp has a variable, non-constant gradient.
14. The apparatus of claim 1 , comprising a bearing provided between the moveable component and the static component and arranged to constrain movement of the moveable component along the second axis.
15. The apparatus of claim 1 , wherein the moveable component is a button, and wherein the apparatus further comprises a sensor to detect a button press and control circuitry coupled to the sensor and the at least one SMA actuator wire and arranged to:
receive data from the sensor indicating that the button has been pressed; and
send a signal to drive the at least one SMA actuator wire.
16. The apparatus of claim 1 , comprising a plurality of SMA actuator wires arranged to move the intermediate moveable element in the same direction along the second axis.
17. The apparatus of claim 1 , comprising a plurality of SMA actuator wires, wherein the plurality of SMA actuator wires comprises a first group of wires and a second group of wires, where the first group of wires are arranged to move the intermediate moveable element in a first direction along the second axis, and the second group of wires are arranged to move the intermediate moveable element in a second direction along the second axis.
18. The apparatus of claim 1 , further comprising a resilient biasing element coupled to the intermediate moveable element and arranged to oppose the movement of the intermediate moveable element caused by contraction of the at least one SMA actuator wire.
19. The apparatus of claim 1 , wherein each SMA actuator wire is coupled to the at least one intermediate moveable element via a crimp connector.
20. An apparatus comprising:
a static component;
a moveable component that is moveable along a first axis relative to the static component;
at least one assembly arranged to move the moveable component, the assembly comprising:
at least one intermediate moveable element rotatable about a second axis that is parallel to the first axis and arranged in contact with the moveable component so as to drive movement of the moveable component; and
at least one shape memory alloy (SMA) actuator wire coupled to the at least one intermediate moveable element and arranged to, on contraction, drive movement of the intermediate moveable component.