Control Method of Optical Deflector, and Optical Deflection Device

A method for controlling an optical deflector that changes a deflection angle depending on a voltage to be applied, the method for controlling the optical deflector deriving a goal voltage V=ggoal(t) for providing a deflection angle θ with goal time dependency θ=θgoal(t) when time is denoted by t, the method comprising:

• an initial step comprising:
• setting a period of a periodic function of time as T when θ is the periodic function of time, a period is denoted by T;
• setting a duration as T and setting a start time of the deflection angle θ with the goal time dependency θ=θgoal(t) as t=0 when θ is not a periodic function of time;
• and
• setting a number of repetitions as n=0 when time in a period 0≤t<T is considered;
• an increment step of setting n=n+1;
• a step An of applying a voltage gn(t) with the period T or the duration T to the optical deflector;
• a step Bn of checking whether θ=θgoal(t) is satisfied with a goal accuracy, adjacent to the step An;
• a step Cn of setting gn(t) as the goal voltage V=ggoal(t);
• a step Dn of deriving a relationship of voltage dependency θ=fn(V) of the deflection angle;
• a step En of setting gn+1(t)=fn−1 {θgoal(t)}, next to the step Dn;
• and
• a step Fn of performing the increment step next to the step En,
• wherein the step An is subsequent to the increment step,
• wherein in the step Bn, in a case where θ=θgoal(t) is not satisfied with the goal accuracy, the step Dn is performed following the step Bn,
• wherein in the step Bn, in a case where θ=θgoal(t) is satisfied with the goal accuracy, the step Cn is performed following the step Bn and a process is ended, and
• wherein the voltage dependency θ=fn(V) of the deflection angle depends on a time dependency of an applied voltage.

An optical deflection device comprising:

• an optical deflector configured to change a deflection angle depending on a voltage to be applied;
• a voltage controller configured to apply the voltage to the optical deflector;
• and
• a storage device configured to store a value of a voltage output by the voltage controller,
• wherein the storage device is configured to store a goal voltage V=ggoal(t) for providing a deflection angle θ with goal time dependency θ=θgoal(t) when time is denoted by t, and
• the goal voltage V=ggoal(t) is determined by a method, the method comprising:
• an initial step comprising:
• setting a period of a periodic function of time as T when θ is the periodic function of time, a period is denoted by T;
• setting a duration as T and setting a start time of the deflection angle θ with the goal time dependency θ=θgoal(t) as t=0 when θ is not a periodic function of time;
• and
• setting a number of repetitions as n=0 when time in a period 0≤t<T is considered;
• an increment step of setting n=n+1;
• a step An of applying a voltage gn(t) with the period T or the duration T to the optical deflector;
• a step Bn of checking whether θ=θgoal(t) is satisfied with a goal accuracy, adjacent to the step An;
• a step Cn of setting gn(t) as the goal voltage V=ggoal(t);
• a step Dn of deriving a relationship of voltage dependency θ=fn(V) of the deflection angle;
• a step En of setting gn+1(t)=fn−1{θgoal(t)}, next to the step Dn;
• and
• a step Fn of performing the increment step next to the step En,
• wherein the step An is subsequent to the increment step,
• wherein in the step Bn, in a case where θ=θgoal(t) is not satisfied with the goal accuracy, the step Dn is performed following the step Bn,
• wherein in the step Bn, in a case where θ=θgoal(t) is satisfied with the goal accuracy, the step Cn is performed following the step Bn and a process is ended, and
• wherein the voltage dependency θ=fn(V) of the deflection angle depends on a time dependency of an applied voltage.