Balanced mirror unit for laser deflection device and related balancing method

A mirror unit for a laser deflection device comprising:

• a mirror for deflecting a laser beam, wherein the mirror extends in a mirror plane parallel to a first direction and to a second direction perpendicular to the first direction;
• a rotor for rotating the mirror around a rotation axis parallel to the first direction;
• a mirror holder holding the mirror to the rotor;
• and
• one or more balancing weights attached to the mirror unit, wherein a centre of mass of the one or more balancing weights is arranged in said mirror plane or in a balance plane parallel containing said rotation axis;
• wherein the one or more balancing weights are configured such that when a laser beam is deflected with the mirror upon a laser beam position sensor registering a position of the deflected laser beam on the laser beam position sensor as a position signal and the mirror unit is rotated around the rotation axis thereby causing a translation of the position signal in a first sensing direction corresponding to said rotation, a deviation of the position signal in a second sensing direction perpendicular to the first sensing direction is smaller than in absence of the one or more balancing weights;
• wherein the one or more balancing weights comprise only balancing weights extending in the mirror plane or in the balance plane and/or only balancing weights extending pairwise symmetric with respect to the mirror plane or to the balance plane;
• wherein the mirror unit is free of balancing weights that are not arranged extending in the mirror plane or in the balance plane or extending pairwise symmetric with respect to the mirror plane or to the balance plane.

A mirror unit for a laser deflection device comprising:

• a mirror for deflecting a laser beam, wherein the mirror extends in a mirror plane parallel to a first direction and to a second direction perpendicular to the first direction;
• a rotor for rotating the mirror around a rotation axis parallel to the first direction;
• a mirror holder holding the mirror to the rotor;
• and
• at least two balancing weights attached to the mirror unit, wherein a centre of mass of the at least two balancing weights is arranged in said mirror plane;
• wherein the at least two balancing weights are configured such that when a laser beam is deflected with the mirror upon a laser beam position sensor registering a position of the deflected laser beam on the laser beam position sensor as a position signal and the mirror unit is rotated around the rotation axis thereby causing a translation of the position signal in a first sensing direction corresponding to said rotation, a deviation of the position signal in a second sensing direction perpendicular to the first sensing direction is smaller than in absence of the at least two balancing weights.