US 11,988,846 B2
Optical system and optical apparatus including the same
Tomohiko Ishibashi, Tochigi (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Oct. 16, 2020, as Appl. No. 17/073,170.
Claims priority of application No. 2019-192821 (JP), filed on Oct. 23, 2019.
Prior Publication US 2021/0124182 A1, Apr. 29, 2021
Int. Cl. G02B 27/58 (2006.01); G02B 5/00 (2006.01); G02B 9/12 (2006.01); G02B 13/18 (2006.01)
CPC G02B 27/58 (2013.01) [G02B 5/005 (2013.01); G02B 9/12 (2013.01); G02B 13/18 (2013.01)] 14 Claims
OG exemplary drawing
 
1. An optical system comprising:
an aperture stop;
a first optical element disposed on an object side of the aperture stop; and
a second optical element disposed on an image side of the aperture stop,
wherein each of the first optical element and the second optical element includes an area in which a transmittance changes in a direction perpendicular to an optical axis, and
wherein the following conditional expressions are satisfied:
0.60≤|m1/a1|<|m2/a2|≤1.20,
0.40≤T1(h1)/T2(h2)<0.98,
0.30≤2×h1/φ1≤0.70, and
0.80≤|m1/a1|/|m2/a2|<1.00
where a1 is a maximum height from the optical axis of an axial ray in the first optical element, a2 is a maximum height from the optical axis of an axial ray in the second optical element, m1 is a maximum height from the optical axis of an outermost off-axis ray in the first optical element, m2 is a maximum height from the optical axis of an outermost off-axis ray in the second optical element, T1(h) is a transmittance of the first optical element at a height h from the optical axis, T2(h) is a transmittance of the second optical element at the height h from the optical axis, φ1 is an effective diameter of the first optical element, φ2 is an effective diameter of the second optical element, and ray heights h1 and h2 satisfy h1/φ1=h2/φ2.