Bi-directional stiffness for optical image stabilization in a dual-aperture digital camera
Mechanisms for providing optical image stabilization in at least one direction as well as auto-focus in a digital camera comprise a plurality of springs mechanically coupled to at least a lens module carrying a lens of the digital camera, wherein the plurality of springs provides overall low stiffness to movement of the lens in two, first and second directions orthogonal to each other, and provides high stiffness to torsion of the lens module.
1. A mechanism for providing optical image stabilization (OIS) in at least one direction in a digital camera, comprising: a plurality of springs mechanically coupled to at least a lens module carrying a lens of the digital camera, wherein the plurality of springs provides overall low stiffness to movement of the lens module in two, first and second directions orthogonal to each other and high stiffness to torsion of the lens module such that a ratio between natural frequencies arising from the high stiffness and the low stiffness is greater than 2.
2. The mechanism of claim 1 , wherein the plurality of springs includes a first plurality of springs with low stiffness in the first direction and high stiffness in the second direction; and a second plurality of springs with high stiffness in the first direction and low stiffness in the second direction.
3. The mechanism of claim 2 , wherein the first plurality of springs includes two pairs of leaf springs and wherein the second plurality of springs includes a pair of cross springs.
4. The mechanism of claim 2 , wherein the first plurality of springs includes a pair of leaf springs and one cross spring and wherein the second plurality of springs includes a pair of cross springs.
5. The mechanism of claim 2 , wherein each of the first and second pluralities of springs includes a pair of cross springs.
6. The mechanism of claim 1 , wherein the ratio between natural frequencies arising from the high stiffness and the low stiffness is greater than 3.
7. The mechanism of claim 1 , wherein the ratio between natural frequencies arising from the high stiffness and the low stiffness is greater than 5.
8. The mechanism of claim 1 , wherein the ratio between natural frequencies arising from the high stiffness and the low stiffness is greater than 10.
9. The mechanism of claim 1 , wherein the mechanism is dimensioned to accommodate the lens module without obstructing an optical path passing through the lens.
10. The mechanism of claim 1 , wherein the plurality of springs includes a pair of cross springs.
11. The mechanism of claim 1 , wherein the plurality of springs includes a mix of leaf springs and cross springs.
12. The mechanism of claim 1 , wherein the digital camera is a dual-optical module camera.
13. The mechanism of claim 1 , wherein the lens module is a folded lens module.
14. The mechanism of claim 1 , adapted to perform auto-focus.