US 11,860,504 B2
Optical scanning device
Yukito Saitoh, Minamiashigara (JP); and Hiroshi Sato, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on Jun. 24, 2022, as Appl. No. 17/849,167.
Application 17/849,167 is a continuation of application No. PCT/JP2020/048962, filed on Dec. 25, 2020.
Claims priority of application No. 2019-236320 (JP), filed on Dec. 26, 2019.
Prior Publication US 2022/0326565 A1, Oct. 13, 2022
Int. Cl. G02F 1/29 (2006.01); G02F 1/1335 (2006.01)
CPC G02F 1/29 (2013.01) [G02F 1/133504 (2013.01)] 7 Claims
OG exemplary drawing
 
1. An optical scanning device comprising:
a light source; and
a light deflection element,
wherein the light deflection element includes a support and an optically anisotropic layer which is a cured layer of a liquid crystal composition,
an optical axis of a liquid crystal compound contained in the liquid crystal composition is parallel to a surface of the optically anisotropic layer, and the optically anisotropic layer has a liquid crystal alignment pattern which is arranged along at least one in-plane direction of the optically anisotropic layer and in which an orientation of the optical axis of the liquid crystal compound changes continuously and rotationally,
the support has anisotropy in a linear expansion coefficient, and a direction in which the linear expansion coefficient of the support is high is parallel to the one direction of the liquid crystal alignment pattern of the optically anisotropic layer, and
the support satisfies Conditional Expression (1),
|dλ/(dt×λ0)−α|2×10−4/° C.  (1)
here,
λ0: a central wavelength of the light source at 25° C. (nm),
dλ: an increment in central wavelength of the light source due to a temperature increase (room temperature from 25° C. to 65° C.) (nm),
dt: an increment in temperature (° C.: room temperature from 25° C. to 65° C.), and
α: the linear expansion coefficient of the support (1/° C.).