Method and device scanning a two-dimensional brush through an acousto-optic deflector (AOD) having an extended field in a scanning direction
AssigneeMicronic AB
InventorsTorbjörn Sandström, Hans Martinsson
Life of this patent
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Abstract
The technology disclosed relates to improved acousto-optic deflectors (AODs). In particular, it relates to compensation for subtle effects not previously addressed by AOD designers. A shifting center of gravity is described and addressed using advanced power equalisation strategies. Denser writing brushes are provided by using a two-dimensional array of beams with corrections for factors such as angle of incidence at the AOD interface. The compensation and dense brush features can be used separately or in combination.
Claims7
A method of using an acousto-optic deflector (AOD), including:
- applying a variable frequency RF driving power to a transducer coupled to the AOD, wherein the RF driving power decreases as the variable frequency increases;
- and
- compensating for lesser diffraction efficiency at higher RF driving frequencies by varying base power of one or more flying spots deflected by the AOD onto a workpiece, wherein the base power increases as the variable frequency increases.
A method of improving writing quality in a pattern generator comprising at least one acousto-optic deflector (AOD) by using advanced equalisation, including:
- decreasing the RF power in the driving of the AOD with increasing RF frequency in order to reduce or eliminate the variation of the slope in the power profiles in the AOD, thereby improving writing quality by reducing or essentially eliminating at least one of telecentricity errors, aberrations and varying scan length.
Dependencies are inferred from the claim text.