US 12,189,229 B2
Liquid crystal diffraction element comprising an optical axis derived from a liquid crystal compound that continuously rotates in at least one in-plane direction, image display apparatus, and head mounted display
Takashi Yonemoto, Minamiashigara (JP); Masaaki Suzuki, Minamiashigara (JP); Koji Iijima, Minamiashigara (JP); Hiroshi Sato, Minamiashigara (JP); and Ayato Sekine, Minamiashigara (JP)
Assigned to FUJIFILM Corporation, Tokyo (JP)
Filed by FUJIFILM Corporation, Tokyo (JP)
Filed on May 31, 2024, as Appl. No. 18/679,967.
Application 18/679,967 is a continuation of application No. PCT/JP2022/044513, filed on Dec. 2, 2022.
Claims priority of application No. 2021-197022 (JP), filed on Dec. 3, 2021; and application No. 2022-122076 (JP), filed on Jul. 29, 2022.
Prior Publication US 2024/0319532 A1, Sep. 26, 2024
Int. Cl. G02F 1/1335 (2006.01); G02B 27/01 (2006.01); G02F 1/13363 (2006.01)
CPC G02F 1/133504 (2013.01) [G02B 27/0172 (2013.01); G02F 1/13363 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A liquid crystal diffraction element comprising:
at least an optically-anisotropic layer that is formed of a liquid crystal composition including a liquid crystal compound,
wherein the optically-anisotropic layer has a liquid crystal alignment pattern in which an orientation of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction,
in a case where a length over which the optical axis rotates by 180 degrees in the one direction is set as a single period, the single period gradually changes in the one direction, and
in a case where an average period of 50 periods in the one direction from a period having a longest length of the single period is represented by Λa and a main surface of the optically-anisotropic layer in a region having a period shorter than or equal to the average period Λa is observed with an optical microscope, both of a ratio between a maximum value and a minimum value among widths of 30 continuous bright lines and a ratio between a maximum value and a minimum value among widths of 30 continuous dark lines in the region are 1.2 or less.