Patent ID: 11921235
Assignee: KAWASAKI JUKOGYO KABUSHIKI KAISHA
Field: Optics (Instruments)
Classification: CPC B  G | IPC G

Claim 10:
11. An optical scanning device, comprising:
a rotation mirror;
a drive unit for rotating the rotation mirror; and
an irradiation device that irradiates light onto the rotation mirror,
wherein the rotation mirror comprises:
a first regular polygon pyramid; and
a second regular polygon pyramid arranged facing the first regular polygon pyramid with an axis coincident with the first regular polygon pyramid,

wherein side surfaces of each of the first regular polygon pyramid and the second regular polygon pyramid are light reflection surfaces each of which is formed in a planar shape,
wherein the number of sides of regular polygons is equal in a first base surface that the first regular polygon pyramid has and a second base surface that the second regular polygon pyramid has,
wherein the first base surface and the second base surface are both arranged perpendicular to the axis,
wherein the first regular polygon pyramid and the second regular polygon pyramid are rotated integrally with each other around the axis as a rotation axis by the drive unit while a phase of the regular polygon of the first base surface and a phase of the regular polygon of the second base surface are matched with each other,
wherein a base angle of the first regular polygon pyramid is α° when the first regular polygon pyramid is cut along a plane that includes the axis and a midpoint of one of the sides of the regular polygon of the first base surface,
wherein a base angle of the second regular polygon pyramid is (90−α°) when the second regular polygon pyramid is cut along a plane that includes the axis and a midpoint of one of the sides of the regular polygon of the second base surface,
wherein a distance between the first base surface and the second base surface is equal to the sum of a distance between the midpoint of one side of the regular polygon of the first base surface and the rotation axis multiplied by tan α and a distance between the midpoint of one side of the regular polygon of the second base surface and the rotation axis multiplied by tan(90−α), and
wherein the irradiation device irradiates the light toward a position so that the light intersects the rotation axis of the rotation mirror.