Apparatus and method for controlling the spatial beam position of laser beams and an actuator for use with this apparatus and method
OwnerThomas Mueller-Wirtsinventor
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Abstract
Apparatus and method are disclosed for controlling the spatial beam position of laser beams, e.g., in a laser exposure device, using a position detector for determining the current (actual), beam position and a control element for determining the control quantity based on the difference between the actual and the desired beam position. An actuator that moves an optical element, which in turn guides the laser beam, is provided for changing the beam position. The actuator includes a controllable heating element that is connected to a position-determining actuator element, for moving the actuator element and, thus, the optical element, through thermal expansion due to heating of the actuator element.
Claims23
Apparatus for controlling the spatial beam position of laser beams comprising, in combination:
- (a) a position detector for determining the current, actual beam position;
- (b) a control element for determining a control quantity based on the actual and the desired beam position;
- (c) a movable optical element for changing the beam position;
- (d) an actuator element, coupled to the optical element, for adjusting the position of the optical element;
- and
- (e) a controllable heating element coupled to the position-adjusting actuator element, for moving the actuator element by means of thermal expansion due to the heating of the actuator element.
In a method for controlling the spatial beam position of a laser beam, wherein the current, actual beam position is determined using a position detector, a control quantity is determined based on the actual and the desired beam position, and the beam position is changed according to the control quantity using an optical element that is moved by an actuator having at least one position-adjusting actuator element, the improvement comprising the step of changing the beam position by controlled thermal expansion of said at least one position-adjusting actuator element.
An actuator for moving optical elements for influencing the spatial beam position of laser beams comprising in combination:
- (a) a carrier element for optical elements;
- (b) at least one position-determining, thermal actuator element that is connected to the carrier element and whose expansion can be changed through heating;
- (c) at least one static actuator element that is connected to the carrier element;
- and
- (d) a controllable heating element for heating the position-determining thermal actuator element.
Dependencies are inferred from the claim text.