Single actuator configuration for a camera module
View Patent ↗Systems and methods for camera modules having a movable lens barrel, allowing a maximum lens diameter with minimal outside dimensions are disclosed. At least one single linear actuator is moving the lens barrel. Each actuator is deployed in an own corner of the camera module. The moving lens barrel is guided by rolling elements bearings. The actuator comprises a stator, comprising one or more coils wrapped around a rod of magnetic metal and an anchor comprising one or more permanent magnets, which are tightly attached to the lens barrel. An offset between the longitudinal center line of magnets of the anchor and the center of the stator generates a permanent force pushing the lens barrel in direction of the stator of the motor and consequently pushes protrusions on the lens barrel onto the rolling elements bearings, thus preventing the bearings to fall apart in case of a mechanical shock.
1. A camera comprising: an image sensor; a movable lens barrel; at least one linear actuator to move said lens barrel, wherein said at least one linear actuator is deployed in a corner of the camera, wherein the at least one linear actuator generates a pre-load force on rolling element bearings; wherein at least two rolling element bearings are provided at a circumferential surface of the barrel wherein one of said at least two rolling element bearings is tangentially oriented and an other of said at least two rolling element bearings is radially oriented, and wherein the pre-load force of the at least one linear actuator comprises a tangential component so that the tangentially oriented rolling element bearing is pressed against a corresponding abutting surface.
2. A camera according to claim 1 , comprising a shutter with an aperture function driven by a linear motor; said linear motor driving the shutter, wherein the linear motor has an integrated position sensing system.
3. A camera according to claim 2 comprising an integrated circuit controlling the linear motor driving the shutter and the at least one linear actuator moving the lens barrel; and said rolling elements bearings wherein rolling elements of each rolling element bearing are moving between the lens barrel and a fixed part of the camera.
4. A camera according to claim 1 , wherein an offset is implemented between a longitudinal center line of magnets of an anchor of the at least one linear actuator and a longitudinal center line of a stator of the at least one linear actuator, wherein the offset generates permanent force in a tangential direction.
5. The camera according to claim 1 , wherein said rolling element bearings are ball bearings.
6. The camera according to claim 1 , wherein said rolling element bearings are roller bearings.
7. The camera according to claim 1 , wherein protrusions of the lens barrel are used to apply a pre-load force on the rolling element bearings.
8. The camera according to claim 1 , wherein at least one of said linear actuators has an integrated position sensing system.