Lens device comprising a displaceable lens and laser scanning system
Shown is a lens device 16 comprising a displaceable lens 18 and a guide 42 , by means of which the lens is guided so as to be capable of being displaced. The lens device 16 comprises a first and a second galvanometric motor 46 a , 46 b and a first and a second force transmission device 54 a , 56 a ; 54 b , 56 b , which is coupled to the rotor of the first and second galvanometric motor 46 a , 46 b , respectively, and which is coupled to the lens 18 at a first and second junction 58 a , 58 b , respectively. The force transmission device is suitable to convert a rotary motion of the rotor of the first and second galvanometric motor 46 a , 46 b , respectively, into a displacement motion of the lens 18 . The first and the second junction 58 a , 58 b are thereby spaced apart from one another in a direction at right angles to the displacement direction of the lens 18.
1. A lens device having an adjustable lens, comprising:
a guide for guiding a displacement of said lens;
a first and a second galvanometric motors; and
a first and a second force transmission devices which are coupled to a rotor of said first and second galvanometric motors, respectively, and which are coupled to said lens at a first and second junctions, respectively,
wherein said first and second force transmission devices convert a rotary motion of the rotors of said first and second galvanometric motors, respectively, into a displacement motion of said lens, and
wherein said first and second junctions are spaced apart from one another in a direction having at least a component at right angles to the displacement direction of said lens.
2. The lens device according to claim 1 , wherein said first force transmission device comprises an arm which is rotationally fixed to the rotor of said first galvanometric motor and comprises a link having a first end connected to said arm in an articulated manner and a second end connected to said first junction.
3. The lens device according to claim 1 wherein said first and second galvanometric motors are arranged next to one another and parallel to one another below or above a displacement plane in which said lens is displaced, and wherein a respective free end of the rotors of said first and second galvanometric motors point in different directions.
4. The lens device according to claim 3 wherein said guide comprises at least two parallel guide rods or rails and the displacement plane is a plane in which said guide rods or rails are arranged.
5. The lens device according to claim 1 wherein said guide is fixed to a housing of at least one of said first and second galvanometric motors.
6. The lens device according to claim 1 wherein said lens is held in a lens holder which comprises at least two sliding elements which are spaced apart from one another at right angles to a displacement direction of said lens and which are slideably connected to said guide.
7. The lens device according to claim 6 , wherein said sliding elements comprise linear roll bearings.
8. The lens device according to claim 6 wherein a center of said lens is displaced in a direction away from said first and second galvanometric motors with reference to an imaginary connecting line between said sliding elements.
9. The lens device according to claim 1 wherein said lens, said guide and said first and second galvanometric motors are arranged in a housing.
10. The lens device according to claim 1 further comprising a control for controlling said first and second galvanometric motors in such a manner that a first coil current, which leads to a desired position of said lens, is generated in said first galvanometric motor and a second coil current, which is inverted with respect to said first coil current, is applied to said second galvanometric motor.
11. A laser scanning system comprising: a deflection unit for scanning a laser beam across a target surface, said deflection unit comprising said lens device according to claim 1 and a control device for displacing said lens device as a function of an impact point of the laser beam on the target surface in such a manner that the laser beam is focused on the impact point.
12. A method of illuminating a target with a laser beam, the method comprising:
(a) passing a laser beam through a lens coupled to a sliding element such that said laser beam reflects off at least one displacement mirror and illuminates a first point on a target such that said laser beam is focused on said first point;
(b) moving said at least one displacement mirror to thereby illuminate a second point on said target; and
(c) focusing said laser beam on said second point by:
(i) rotating at least one of a first rotor of a first galvanometric motor and a second rotor of a second galvanometric motor;
(ii) converting the rotary motion of said first and second rotors into linear motion of said lens, wherein said lens is displaced in a plane different than a plane containing said first and second rotors; and
(iii) controlling the rotary motion of said first and second rotors so that said laser beam is focused on said second point.
13. The method of claim 12 wherein the step of converting the rotary motion of said first and second rotors into linear motion of said lens is accomplished via a first and a second force transmission device, wherein said first and second force transmission devices are coupled to said first and second rotors, respectively, and coupled to said sliding element at a first and a second junction, respectively, wherein said first and second junctions are spaced apart from one another in a direction having at least a component at right angles to said linear motion of said lens.