An exemplary camera module includes a lens mount, a lens unit, a magnet unit, a printed circuit board (PCB)-based Rogowski coil and a blade spring. The PCB-based Rogowski coil is fixed around the lens unit. The PCB-based Rogowski coil establishes an induced magnetic field when an electric current is applied thereto. The induced magnetic field interacts with the magnet unit to generate a magnetic force moving the lens unit telescopically. The blade spring includes a plurality of ribs. Each rib includes a moveable end connected with the lens unit and an opposite fixed end. The moveable end moves together with the lens unit with respect to the fixed end to cause the ribs to distort and generate an elastic force. The lens unit stops at a focal position when the magnetic force and the elastic force come to a balance.
1. A camera module comprising:
a lens mount;
a lens unit received in the lens mount, the lens unit comprising a lens barrel and a lens received therein;
a magnet unit comprising at least one magnet mounted around the lens unit;
a printed circuit board-based Rogowski coil fixed around the lens barrel, establishing an induced magnetic field when an electric current is applied thereto, the induced magnetic field of the printed circuit board-based Rogowski coil interacting with a magnetic field of the at least one magnet of the magnet unit to generate a magnetic force telescoping the lens unit with the printed circuit board-based Rogowski coil; and
a blade spring fixed around the lens barrel, the blade spring comprising a first elastic element and a second elastic element spaced from each other, and at least two ribs, each of the first and the second elastic elements comprising an inner frame and an outer frame, the at least two ribs interconnected between the inner frames and the outer frames of the first and the second elastic elements respectively, the at least two ribs each comprising a moveable end connected with the lens unit and an opposite fixed end, the moveable ends moving together with the lens unit with respect to the fixed ends to cause the at least two ribs to distort and generate an elastic force during the telescopic movement of the lens unit, the lens unit stopping at a focal position when the magnetic force and the elastic force come to a balance;
wherein each of the first and the second elastic elements forms a connecting pin on the inner frame, and the printed circuit board-based Rogowski coil forms a first pad and a second pad thereon for electrically connecting with the connecting pins of the first and the second elastic elements respectively.
2. The camera module of claim 1 , wherein the inner frame of each of the first and the second elastic elements is connected with the printed circuit board-based Rogowski coil, and the outer frame of each of the first and the second elastic elements is connected with one of the lens mount and the magnet unit.
3. The camera module of claim 2 , wherein each of the ribs comprises a first end connected with the inner frame and a second end connected with the outer frame, the first end functions as the moveable end, and the second end functions as the fixed end.
4. The camera module of claim 1 , wherein the printed circuit board-based Rogowski coil comprises a plurality of series-wound imprinted coils to form a coil around a center thereof, the first pad and the second pad of the printed circuit board-based Rogowski coil are electrically connected with two opposite ends of the coil respectively.
5. The camera module of claim 1 , wherein the lens mount comprises a base and a cover, the outer frames of the first and the second elastic elements being sandwiched between the base and the cover of the lens mount.
6. The camera module of claim 5 , wherein the base comprises a bottom plate and a plurality of sidewalls extending from an outer periphery of the bottom plate toward the cover, a plurality of locking walls extending from the sidewalls of the base towards the cover, the cover comprising a top plate and a plurality of sidewalls extending from an outer periphery of the top plate toward the base, a plurality of grooves defined in the sidewalls of the cover for receiving the locking walls of the base therein.
7. The camera module of claim 1 , wherein each of the first elastic element and the second elastic element comprises a guiding pin extending from the outer frame towards a bottom surface of the lens mount adapted for electrically connecting a power supply arranged just under the lens mount.
8. The camera module of claim 1 , wherein each of the at least two ribs comprises a plurality of folded segments between the fixed end and the moveable end.
9. The camera module of claim 1 , wherein the at least one magnet unit comprises an upper magnet and a lower magnet mounted around a top side and a bottom side of the lens unit respectively, and a clearance is defined between an inner surface of each magnet and an outer surface of the lens unit.
10. The camera module of claim 9 , wherein a space is defined between the upper magnet and the lower magnet, with the blade spring and printed circuit board-based Rogowski coil received therein, the space being taller than the sum of heights of the blade spring and the printed circuit board.
11. The camera module of claim 1 , wherein a guiding tab outwardly extends from an outer surface of the lens barrel, and a groove is defined in an inner surface of the at least one magnet for receiving the tab therein.