Abstract This invention relates to a retrofocus-type extreme wide-angle objective lens having an angle of field of over 108* and comprising a front group dispersing lens system and a rear group convergent lens system on both sides of the diaphragm, wherein the lens system is formed by the front group dispersing system comprising a cemented positive meniscus lens L1, negative meniscus lenses L2 and L3, and a cemented positive lens 4, and a negative meniscus lens lens l5, and the rear group convergent system comprising a cemented positive lens L6, a cemented negative lens L7, and positive meniscus lenses L8 and L9 having the concave surface faced to the direction of incoming light respectively, and the above mentioned two groups are arranged on both sides of the diaphragm, and the aberrations are balanced and the sagittal image surface which tends to become positive in the marginal region of the picture is well corrected by widening the position of inflecting point of the meridional image surface by giving the following conditions: R11 <R12 II d13>d12 III d14+d15>d16 Where R is a radius of curvature and d is the center thickness of a lens or lens spacing.
Inventors
👤 Ikuo Mori
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-29 17:41
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/04
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
215 words
A retrofocus type extreme wide-angle lens comprising a front group dispersing system comprising a positive component L1 formed with a negative meniscus lens and a positive meniscus lens cemented together, the cemented surface of said component L1 being convex toward the object, negative meniscus components L2 and L3 having surfaces convex towards the object respectively, a positive component L4 formed with two negative meniscus lenses cemented with a biconvex lens between them, and a negative meniscus component L5 having surfaces convex towards the object; a rear group converging system comprising a positive component L6 formed with a biconvex lens and a negative meniscus lens cemented together, a component L7 formed with a biconcave lens and a positive meniscus lens, and positive meniscus components L8 and L9, having surfaces concave towards the image respectively; and a diaphragm place in between said systems, the following conditions being met I R11 <R12 II d 13 >d12 III d14+ d15 >d16 where R11denotes the radius of curvature of rear surface of component L4, R12 denotes the radius of curvature of front surface of component L5, d12 denotes the thickness of component L5, d13 denotes the air space between components L5 and L6, d14+d15 denotes the thickness of components L6, d16 denotes the air space between components L6 and L7.
Claim 2
Dependent Claim
215 words
A retrofocus type extreme wide-angle lens comprising a front group dispersing system comprising a positive component L1 formed with a negative meniscus lens and a positive meniscus lens cemented together, the cemented surface of said component L1 being convex toward the object, negative meniscus components L2 and L3 having surfaces convex towards the object respectively, a positive component L4 formed with two negative meniscus lenses cemented with a biconvex lens between them, and a negative meniscus component L5 having surfaces convex towards the object; a rear group converging system comprising a positive component L6 formed with a biconvex lens and a negative meniscus lens cemented together, a component L7 formed with a biconcave lens and a positive meniscus lens, and positive meniscus components L8 and L9, having surfaces concave towards the image respectively; and a diaphragm place in between said systems, the following conditions being met I R11 <R12 II d 13 >d12 III d14+ d15 >d16 where R11denotes the radius of curvature of rear surface of component L4, R12 denotes the radius of curvature of front surface of component L5, d12 denotes the thickness of component L5, d13 denotes the air space between components L5 and L6, d14+d15 denotes the thickness of components L6, d16 denotes the air space between components L6 and L7.
Claim 3
Dependent Claim
18 words
A retrofocus-type extreme wide-angle lens according to claim 1, in which the lenses have the following numerical values: