US 12,072,604 B2
Control method of optical deflector, and optical deflection device
Takashi Sakamoto, Tokyo (JP); Yuichi Akage, Tokyo (JP); Tadayuki Imai, Tokyo (JP); Masahiro Ueno, Tokyo (JP); Sohan Kawamura, Tokyo (JP); and Soichi Oka, Tokyo (JP)
Assigned to Nippon Telegraph and Telephone Corporation, Tokyo (JP)
Appl. No. 17/605,049
Filed by Nippon Telegraph and Telephone Corporation, Tokyo (JP)
PCT Filed Apr. 8, 2020, PCT No. PCT/JP2020/015811
§ 371(c)(1), (2) Date Oct. 20, 2021,
PCT Pub. No. WO2020/217991, PCT Pub. Date Oct. 29, 2020.
Claims priority of application No. 2019-082041 (JP), filed on Apr. 23, 2019.
Prior Publication US 2022/0187678 A1, Jun. 16, 2022
Int. Cl. G02F 1/31 (2006.01)
CPC G02F 1/31 (2013.01) 6 Claims
OG exemplary drawing
 
1. 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.