Patent ID: 9151949
Filing Date: 2015-10-06
Classification: G02B,G09G,H04N

Abstract:
1. A deflection device for a projection apparatus for projecting one or more Lissajous figures onto an observation field, which is configured to deflect a light beam about at least one first and one second deflection axes for generating one or more Lissajous figures, the deflection device comprising: a deflection unit, configured for producing oscillations about the deflection axes; and a control apparatus, configured for producing one or more control signals for the deflection unit, the control signals having a first and second control frequencies that substantially correspond to resonant frequencies of the deflection unit; and wherein the deflection unit has a quality factor of >3,000; and wherein the control apparatus includes a first feedback loop that is configured to regulate the first and/or second control frequencies in dependence on a measured phasing of the oscillations of the deflection unit so that a maximum amplitude of the oscillations remains in a resonant range of the deflection unit, such that the control frequencies do not have a substantially fixed integer number ratio.