US 12,287,493 B2
Lens system and image observation apparatus
Manabu Ishioka, Tokyo (JP); Yasutoshi Katsuda, Kanagawa (JP); and Shotaro Tada, Tokyo (JP)
Assigned to Sony Interactive Entertainment Inc., Tokyo (JP)
Filed by Sony Interactive Entertainment Inc., Tokyo (JP)
Filed on Dec. 11, 2023, as Appl. No. 18/534,990.
Application 18/534,990 is a continuation of application No. 17/269,435, granted, now 11,874,448, previously published as PCT/JP2019/033760, filed on Aug. 28, 2019.
Claims priority of application No. 2018-159721 (JP), filed on Aug. 28, 2018; and application No. 2018-196914 (JP), filed on Oct. 18, 2018.
Prior Publication US 2024/0126053 A1, Apr. 18, 2024
Int. Cl. G02B 3/08 (2006.01); G02B 3/04 (2006.01); G02B 5/04 (2006.01); G02B 13/18 (2006.01); G02B 25/00 (2006.01); G02B 27/01 (2006.01); G02B 27/02 (2006.01)
CPC G02B 3/08 (2013.01) [G02B 3/04 (2013.01); G02B 5/04 (2013.01); G02B 13/18 (2013.01); G02B 25/00 (2013.01); G02B 27/0172 (2013.01); G02B 27/02 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A lens system, comprising:
a Fresnel lens, wherein:
a lens surface of the Fresnel lens has a plurality of grooves that is concentrically formed,
both a pitch that is a distance between two adjacent grooves and a depth of each of the plurality of grooves vary with a distance from an optical axis that passes through a center of the lens system,
the pitch in a position at a distance of 0 mm from the optical axis is 1.35 to 2.97 mm,
the pitch in a position at a distance of 5 mm from the optical axis is 0.37 to 0.80 mm, and
the pitch in a position at a distance of 10 mm from the optical axis is 0.30 to 0.66 mm.