Zoom lens apparatus with a piezoelectrically driven moveable platform
A camera having an optic axis and comprising: a lens having a lens optic axis; a platform to which the lens is mounted; a guide track to which the platform is mounted and along which the platform is moveable; wherein the guide track is rotatable between a first position in which the optic axis of the lens substantially coincides with the camera optic axis and a second position in which the lens optic axis does not coincide with the camera optic axis.
1. A zoom lens apparatus comprising:
a lens;
a moveable platform to which the lens is mounted;
ball bearings that move in a direction in which the platform moves when the platform moves;
linear grooves in which the ball bearings are disposed;
a piezoelectric motor having a friction nub and controllable to excite vibrations in the nub to generate force for moving the moveable platform;
a surface to which the friction nub applies the force;
and a resilient element, which generates a coupling force that presses the friction nub to the surface and operates to trap and maintain the ball bearings in the grooves.
2. The apparatus according to claim 1 wherein the grooves are V-grooves.
3. The apparatus according to claim 1 wherein a line of action of the coupling force is displaced from the direction along which the bearings move.
4. The apparatus according to claim 1 wherein the surface is a surface that moves with the platform.
5. The apparatus according to claim 1 wherein the surface is separate from the platform.
6. The apparatus according to claim 1 wherein the surface does not move when the platform moves.
7. The apparatus according to claim 1 wherein the motor is mounted to the platform and moves with the platform.
8. The apparatus according to claim 1 wherein the platform comprises a first elastic element that presses the motor to the platform and a second elastic element separate from the first element that presses the friction nub to the surface.
9. The apparatus according to claim 1 further comprising a second lens platform having a second lens, wherein the second lens platform is mechanically coupled to the first platform and adapted so that motion and position of the first platform along the optic axis can control motion and position of the first platform along the optic axis.
10. The apparatus according to claim 9 wherein the second lens platform comprises a cam that mechanically couples the second platform to the first platform.
11. The apparatus according to claim 10 wherein the cam is formed having first and second slots and the first and second platforms respectively comprise first and second parallel pins perpendicular to the optic axis that seat in the first and second slots and about which pins the cam is rotatable.
12. The apparatus according to claim 10 further comprising a fixed shaft having an axis about which the cam is rotatable.
13. The apparatus according to claim 11 wherein the first and second slots are straight slots.