Optical device production method

An optical device comprising:

• a support portion;
• a movable portion;
• and
• a pair of first torsion bars disposed on both sides of the movable portion on a first axis and supporting the movable portion so that the movable portion is swingable with respect to the support portion around the first axis,
• wherein an optical function portion is provided on one surface of the movable portion and a rib portion is provided on the other surface of the movable portion,
• the rib portion includes eight extending portions of a first extending portion, a second extending portion, a third extending portion, a fourth extending portion, a fifth extending portion, a sixth extending portion, a seventh extending portion, and an eighth extending portion extending from a side of a center of the movable portion to a side of an outer edge of the movable portion respectively when viewed from a predetermined direction perpendicular to the first axis,
• when setting a direction parallel to the first axis as a first axis direction, setting an axis that passes through the center of the movable portion and is perpendicular to the first axis and the predetermined direction as a second axis, and setting a direction parallel to the second axis as a second axis direction, the first extending portion and the second extending portion extend from the side of the center of the movable portion toward one side in the first axis direction so as to interpose the first axis therebetween, the third extending portion and the fourth extending portion extend from the side of the center of the movable portion toward the other side in the first axis direction so as to interpose the first axis therebetween, the fifth extending portion and the sixth extending portion extend from the side of the center of the movable portion toward one side in the second axis direction so as to interpose the second axis therebetween, and the seventh extending portion and the eighth extending portion extend from the side of the center of the movable portion toward the other side in the second axis direction so as to interpose the second axis therebetween,
• when setting directions in which the first extending portion, the second extending portion, the third extending portion, the fourth extending portion, the fifth extending portion, the sixth extending portion, the seventh extending portion, and the eighth extending portion extend as a first extending direction, a second extending direction, a third extending direction, a fourth extending direction, a fifth extending direction, a sixth extending direction, a seventh extending direction, and an eighth extending direction, respectively, and setting an angle between the first extending direction and the second extending direction as a first angle, an angle between the third extending direction and the fourth extending direction as a second angle, an angle between the fifth extending direction and the sixth extending direction as a third angle, and an angle between the seventh extending direction and the eighth extending direction as a fourth angle, each of the first angle and the second angle is larger than each of the third angle and the fourth angle.