Magnetically drivable micromirror

#The present invention relates to a magnetically drivable micromirror, to a method for producing a magnetically drivable micromirror, and to a 2D scanner having a first magnetically drivable micromirror and a second drivable mirror.

#German Patent Application No. DE 102010062591 describes various approaches to the design of magnetically driven micromirrors. The German patent application proposes a design in which unidirectionality of the magnetic field in the chip plane is done without. In contrast, tilting of a micromirror is possible through a Lorentz force, on the basis of an axially symmetrical B field 30. The magnetic system described there is made up of a U-shaped rail 1 made of a material that conducts magnetic flux and a hard magnet 2 situated in this rail and whose direction of magnetization is perpendicular to the rail opening. The main direction of extension of the magnetic system is in the longitudinal direction of the rail. The magnetic system is referred to as a magnetic bracket. In order to produce a torque that rotates the micromirror out of the plane, two printed conductor loops 11 are implemented on the halves of the plate situated opposite one another relative to the axis of rotation, and are supplied with current in the opposite direction of rotation. In this way, the two conductor loops respectively produce a force upward and—opposite the axis of rotation—downward. The magnetic micro-mirror drive shown in German Patent Application No. DE 102010062591 based on a magnetic bracket is particularly suitable for realizing 1D mirrors. The drive structure is described there in detail.

#The present invention relates to a magnetically drivable micromirror having an outer frame, a coil former, and torsion springs situated in a first plane, the torsion springs having an axis of rotation and the coil former being connected to the outer frame by the torsion springs so as to be capable of rotational movement about the axis of rotation, and having a mirror element that is situated in a second plane parallel to the first plane, the mirror element being connected to the coil former by an intermediate layer. Advantageously, the shape of the coil former and the micromirror and their disposition relative to one another are largely independent of one another, because these elements are situated in different planes.

#FIG. 1 schematically shows a plate that can be rotated in an axis, having two conductor loops.

#FIGS. 2a and 2b schematically show a magnetic actuator having a magnetic bracket and a plate rotatable in an axis.

#FIGS. 3 and 4 show an exemplary embodiment of a magnetically drivable micromirror according to the present invention.

#FIG. 1 schematically shows a plate rotatable in an axis having two conductor loops as described in German Patent Application No. DE 102010062591.

#In order to produce a torque that rotates plate 3 out of the plane, two printed conductor loops are implemented on halves of the plate that are situated opposite one another relative to the axis of rotation and are provided with current in opposite directions of rotation. In this way, the two conductor loops 10a, 10b respectively produce a force upward and—opposite axis of rotation 4—downward.

#Here, end faces 20 of loops 10a and 10b do not exert any normal forces on the plate, because here the magnetic field and the current direction run parallel. The printed conductors leading back in the center of the plate exert a force that counteracts the desired force acting normally on the plate. Due to the small distance to the axis of rotation and the significantly smaller magnetic field in the xy plane, the contribution is however negligible. Overall, exactly as in the case of a conductor loop and a unidirectional B field, in the proposed system of an axially symmetrical B field and two conductor loops a torque is obtained on the plate about axis 4 that is equally large, to a first approximation. If, in contrast, the two conductor loops are provided with current in the same direction of rotation, end faces 20 bring about an overall torque that acts on the plate about second axis of rotation 30.