Patent ID: 11947074
Assignee: CANON KABUSHIKI KAISHA
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 15:
16. An optical system comprising:
a first unit,
a second unit disposed on an image side of the first unit, and
diaphragm disposed on the image side of the first unit,
wherein the first unit includes a first substrate, and a first lens having a negative refractive power and disposed on the image side of the first substrate,
wherein the second unit includes a second substrate, and a second lens having a positive refractive power and disposed on the image side of the second substrate,
wherein an absolute value of the refractive power on an optical axis of the second lens is larger than that of the first lens,
wherein an image side surface of the first lens is an aspheric surface,
wherein in the aspheric surface of the first lens, a refractive power at an outermost peripheral portion in an effective area is smaller than a refractive power on the optical axis, and
wherein the following inequality is satisfied:

0.53<d0/R1<5.00  (6), where d0 is a distance on the optical axis from an object side surface of the first unit to the diaphragm, and R1 is a radius of curvature on the optical axis of the first lens.