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

Claim 0:
1. An optical system comprising: a first unit,
a second unit disposed on an image side of the first unit, and
a 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:

1.00<R1e/d1<30.00, where R1e is a radius of a curvature of the outermost peripheral portion in the effective area of the first lens, and d1 is a distance on the optical axis from the image side surface of the first lens to the diaphragm.