Lens driving device
A lens driving device includes a lens frame that holds a lens, a rack provided pivotally with respect to the lens frame around a pivot shaft along an optical axis of the lens, a lead screw provided along the optical axis, a spring that makes the rack pivot around the pivot shaft, pushes the rack against the lead screw, and engages a tooth of the rack with a tooth of the lead screw, a driving unit that rotates the lead screw, and a nut that includes an end surface facing the rack along the optical axis with a gap C being included therebetween, that engages with the lead screw with backlash being included therebetween, and that is provided un-rotatably with respect to the lens frame. In a case where a half pitch of the tooth of the lead screw is A and the backlash along the optical axis between the lead screw and the nut is B, A>B+C is satisfied.
1. A lens driving device comprising:
a lens frame that holds a lens;
a rack provided pivotally with respect to the lens frame around a pivot shaft along an optical axis of the lens;
a lead screw provided along the optical axis;
a spring that makes the rack pivot around the pivot shaft, pushes the rack against the lead screw, and engages a tooth of the rack with a tooth of the lead screw;
a driving unit that rotates the lead screw; and
a nut that includes an end surface facing the rack via a gap C along the optical axis, engages with the lead screw with backlash being included therebetween, and is provided un-rotatably with respect to the lens frame, wherein
in a case where a half pitch of the tooth of the lead screw is A, and the backlash along the optical axis between the lead screw and the nut is B,
A>B+C
is satisfied.
2. The lens driving device according to claim 1 , wherein
the nut is a whole-circumference nut including a tooth, which engages with the tooth of the lead screw, in whole circumference.
3. The lens driving device according to claim 1 , wherein
a coupling part of the nut and the lens frame includes
a groove provided along the optical axis in one of the nut and the lens frame, and
a projection provided slidably with respect to the groove and provided in another one of the nut and the lens frame.
4. A lens driving device comprising:
a lens frame that holds a lens;
a rack provided pivotally with respect to the lens frame around a pivot shaft along an optical axis of the lens;
a lead screw provided along the optical axis;
a spring that makes the rack pivot around the pivot shaft, pushes the rack against the lead screw, and engages a tooth of the rack with a tooth of the lead screw;
a driving unit that rotates the lead screw; and
a nut that includes an end surface facing the lens frame via a gap D along the optical axis, engages with the lead screw with backlash being included therebetween, and is provided un-rotatably with respect to the lens frame, wherein
in a case where a half pitch of the tooth of the lead screw is A, and the backlash along the optical axis between the lead screw and the nut is B,
A>B+D
is satisfied.
5. The lens driving device according to claim 4 , wherein
the nut is a whole-circumference nut including a tooth, which engages with the tooth of the lead screw, in whole circumference.
6. The lens driving device according to claim 4 , wherein
a coupling part of the nut and the lens frame includes
a groove provided along the optical axis in one of the nut and the lens frame, and
a projection provided slidably with respect to the groove and provided in another one of the nut and the lens frame.
7. A lens driving device comprising:
a lens frame that holds a lens;
a rack provided pivotally with respect to the lens frame around a pivot shaft along an optical axis of the lens;
a lead screw provided along the optical axis;
a spring that makes the rack pivot around the pivot shaft, pushes the rack against the lead screw, and engages a tooth of the rack with a tooth of the lead screw;
a driving unit that rotates the lead screw; and
a nut that includes one end surface facing the rack via a gap C along the optical axis and another end surface facing the lens frame via a gap D along the optical axis, engages with the lead screw with backlash being included therebetween, and is provided un-rotatably with respect to the lens frame, wherein
in a case where a half pitch of the tooth of the lead screw is A and the backlash along the optical axis between the lead screw and the nut is B,
A>B+C and
A>B+D
are satisfied.
8. The lens driving device according to claim 7 , wherein
the nut is a whole-circumference nut including a tooth, which engages with the tooth of the lead screw, in whole circumference.
9. The lens driving device according to claim 7 , wherein
a coupling part of the nut and the lens frame includes
a groove provided along the optical axis in one of the nut and the lens frame, and
a projection provided slidably with respect to the groove and provided in another one of the nut and the lens frame.