US 12,321,041 B2
Objective lens
Takao Tanabe, Kanagawa (JP)
Assigned to KYOCERA SOC Corporation, Yokohama (JP)
Filed by KYOCERA SOC Corporation, Kanagawa (JP)
Filed on Oct. 19, 2022, as Appl. No. 17/969,225.
Claims priority of application No. 2022-035127 (JP), filed on Mar. 8, 2022.
Prior Publication US 2023/0288670 A1, Sep. 14, 2023
Int. Cl. G02B 9/64 (2006.01); G02B 1/02 (2006.01)
CPC G02B 9/64 (2013.01) [G02B 1/02 (2013.01)] 4 Claims
OG exemplary drawing
 
1. A nine-element objective lens that includes no cemented lens, has a numerical aperture greater than or equal to 0.75, and has a half-angle of field of view ω greater than or equal to 2.5 degrees, the objective lens comprising, arranged in order from a magnification side:
a first lens consisting of a meniscus lens that has a convex surface facing the magnification side and has a negative refractive power;
a second lens consisting of a biconcave lens;
a third lens consisting of a meniscus lens that has a concave surface facing the magnification side and has a positive refractive power;
a fourth lens consisting of a biconvex lens;
a fifth lens consisting of a meniscus lens that has a convex surface facing the magnification side and has a negative refractive power;
a sixth lens consisting of a biconvex lens;
a seventh lens consisting of a lens that has an arbitrary shape and has a positive refractive power;
an eighth lens consisting of a meniscus lens that has a convex surface facing the magnification side and has a positive refractive power; and
a ninth lens consisting of a meniscus lens that has a convex surface facing the magnification side and has a positive refractive power,
wherein the ninth lens, which is closest to a sample surface, has a thickness 1.5 times to 3 times a focal length of the objective lens.