US 12,449,652 B2
Light deflection device and optical device
Yukito Saitoh, Minamiashigara (JP); and Hiroshi Sato, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Feb. 25, 2022, as Appl. No. 17/681,183.
Application 17/681,183 is a continuation of application No. PCT/JP2020/032865, filed on Aug. 31, 2020.
Claims priority of application No. 2019-156855 (JP), filed on Aug. 29, 2019.
Prior Publication US 2022/0179194 A1, Jun. 9, 2022
Int. Cl. G02B 26/08 (2006.01); G02B 5/18 (2006.01); G02B 26/10 (2006.01)
CPC G02B 26/0833 (2013.01) [G02B 5/18 (2013.01); G02B 26/10 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A light deflection device comprising:
a MEMS light deflection element that comprises a reflection plate and a drive mechanism for the reflection plate and drives the reflection plate by the drive mechanism, whereby incident light is one-dimensionally or two-dimensionally deflected by the reflection plate to be emitted; and
an angle increasing optical element that is disposed downstream of the MEMS light deflection element in a light traveling direction and increases an angle range of a deflection angle of the light emitted from the MEMS light deflection element,
wherein the reflection plate of the MEMS light deflection element has a function of collecting and emitting the incident light,
the angle increasing optical element includes a diffraction element having different periodic structure pitches in a plane,
the diffraction element in the angle increasing optical element is a liquid crystal diffraction element,
the liquid crystal diffraction element includes an optically-anisotropic layer formed of a composition including a liquid crystal compound, the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one direction, and in a case where, in the liquid crystal alignment pattern, a length over which the direction of the optical axis derived from the liquid crystal compound rotates by 180° in the one direction in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating is set as a single period, a length of the single period gradually decreases from an inner side toward an outer side, and
the optically-anisotropic layer has a liquid crystal alignment pattern in a radial shape from an inner side toward an outer side, the liquid crystal alignment pattern being a pattern in which the direction of the optical axis derived from the liquid crystal compound changes while continuously rotating in the one direction.