Auto focus and optical image stabilization in a compact folded camera
Compact folded camera modules having auto-focus (AF) and optical image stabilization (OIS) capabilities and multi-aperture cameras including such modules. In an embodiment, a folded camera module includes an optical path folding element (OPFE) for folding light from a first optical path with a first optical axis to a second optical path with a second optical axis perpendicular to the first optical axis, an image sensor and a lens module carrying a lens with a symmetry axis parallel to the second optical axis. The lens module can be actuated to move in first and second orthogonal directions in a plane perpendicular to the first optical axis, the movement in the first direction being for auto-focus and the movement in the second direction being for OIS. The OPFE can be actuated to tilt for OIS.
1. An optical path folding element (OPFE) actuation sub-assembly, comprising:
a voice coil motor (VCM) actuator for actuating the OPFE to tilt around a virtual hinge axis positioned externally to the OPFE, the VCM actuator including a magnet rigidly coupled to the OPFE and a coil rigidly coupled to a base; and
a Hall-bar located in proximity of the coil or located within a vacant area in the middle of the coil and used for measuring a magnetic field in the Hall-bar correlated with an amount of tilt of the OPFE,
wherein the OPFE has an OPFE object-facing surface and an OPFE height H OPFE measured along a height axis perpendicular to the OPFE object-facing surface,
wherein the virtual hinge axis is located at a distance D from the Hall-bar, the distance D measured along the height axis,
and wherein D>H OPFE to increase a relative motion between the magnet and the Hall-bar for a given tilt angle of the OPFE.
2. The OPFE actuation sub-assembly of claim 1 , wherein D>1.25×H OPFE .
3. The OPFE actuation sub-assembly of claim 1 , wherein the relative motion between the magnet and the Hall-bar is in a tilt range of ±1° from a rest position of the OPFE.
4. The OPFE actuation sub-assembly of claim 1 , wherein the OPFE actuation sub-assembly includes one or more springs.
5. The OPFE actuation sub-assembly of claim 1 , further comprising a hanging structure with a plurality of flexible tilted hanging members that hang the OPFE over the base.
6. The OPFE actuation sub-assembly of claim 5 , wherein the plurality of flexible tilted hanging members includes 4 flexible tilted hanging members.
7. The OPFE actuation sub-assembly of claim 5 , wherein the hanging structure is designed to prevent the OPFE from tilts or translations other than the tilt around the virtual hinge.
8. The OPFE actuation sub-assembly of claim 1 , wherein the OPFE is a prism.
9. The OPFE actuation sub-assembly of claim 1 , wherein the OPFE is a mirror.
10. A folded camera, comprising:
an optical path folding element (OPFE) for folding an optical path from a first direction to a second direction, the OPFE having a height H OPFE measured along the first direction;
a lens;
an image sensor; and
an optical path folding element (OPFE) actuation sub-assembly, comprising:
a voice coil motor (VCM) actuator for actuating the OPFE to tilt around a virtual hinge axis positioned externally to the OPFE, the VCM actuator including a magnet rigidly coupled to the OPFE and a coil rigidly coupled to a base; and
a Hall-bar located in proximity of the coil or located within a vacant area in the middle of the coil and used for measuring a magnetic field in the Hall-bar correlated with an amount of tilt of the OPFE,
wherein the virtual hinge axis is located at a distance D from the Hall-bar, the distance D measured along the first direction,
and wherein D>H OPFE to increase a relative motion between the magnet and the Hall-bar for a given tilt angle of the OPFE.
11. The folded camera of claim 10 , wherein D>1.25×H OPFE .
12. The folded camera of claim 10 , wherein the relative motion between the magnet and the Hall-bar is in a tilt range of ±1° from a rest position of the OPFE.
13. The folded camera of claim 10 , wherein the OPFE actuation sub-assembly includes one or more springs.
14. The folded camera of claim 10 , further comprising a hanging structure with a plurality of flexible tilted hanging members that hang the OPFE over the base.
15. The folded camera of claim 14 , wherein the plurality of flexible tilted hanging members includes 4 flexible tilted hanging members.
16. The folded camera of claim 14 , wherein the hanging structure is designed to prevent the OPFE from tilts or translations other than the tilt around the virtual hinge.
17. The folded camera of claim 10 , wherein the OPFE is a prism.
18. The folded camera of claim 10 , wherein the OPFE is a mirror.
19. The folded camera of claim 10 , included together with a non-folded camera in a dual-aperture camera, and wherein the dual-aperture camera is included in a mobile device.
20. The folded camera of claim 19 , wherein the mobile device is a smartphone.