Apparatus for correcting scanning rate deviation of a galvanometer and correcting method thereof
AssigneeFuji Photo Film Co., Ltd.
InventorsKatsumi Asanuma, Hidetoshi Shinada
Life of this patent
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Abstract
A method and apparatus for correcting deviation from a constant scanning speed of a galvanometer driven by a linear drive signal, characterized in that the linear drive signal for driving the galvanometer is converted into a non-linear drive signal in accordance with predetermined correction data to thereby reduce the deviation to zero.
Claims7
An apparatus for correcting deviation from a constant scanning speed of a galvanometer driven by a linear drive signal, comprising:
- memory means for storing correction data for zeroing the deviation from a constant scanning speed, means for reading out the correction data in response to an input address signal;
- first digital-to-analog converting means for converting the correction data into an analog correction signal;
- second digital-to-analog converting means for converting the input address signal into the linear drive signal;
- and
- adder means for summing the linear drive signal and the analog correction signal to derive a non-linear drive signal for the galvanometer which reduces the deviation to zero.
An apparatus for correcting deviation from a constant scanning speed of a galvanometer driven by a linear drive signal, comprising:
- memory means for storing correction data for a linear drive signal;
- means for reading out the stored correction data in response to an input address signal;
- digital-to-analog converting means for converting the correction data into an analog non-linear drive signal which reduces the speed deviation to zero;
- reference data generating means for generating reference data indicative of any differences between an actual scanning speed of the galvanometer and the constant scanning speed;
- and
- means for updating the correction data stored in the memory means in accordance with the reference data;
- wherein the reference data generating means includes an optical mark signal generator, an optical mark signal counter responsive to the output of said optical mark signal generator, a reference value setter for setting a reference value and a comparator for comparing the output of said optical mark signal counter with said reference value.
An apparatus for correcting deviation from a constant scanning speed of a galvanometer driven by a linear drive signal, comprising:
- random access memory means for storing correction data for a linear drive signal;
- means for reading out the stored correction data in response to an input address signal;
- digital-to-analog converting means for converting the correction data into an analog non-linear drive signal which reduces the speed deviation to zero;
- reference data generating means for generating reference data indicative of any difference between an actual scanning speed of the galvanometer and the constant scanning speed,;
- and
- means for updating the correction data stored in the memory means in accordance with the reference data.
Dependencies are inferred from the claim text.