Abstract A finite conjugation large-aperture lens with aspherical surfaces having aspherical first and second surfaces which meet the condition of the following formula (1) and satisfying the conditions of the following formulae (2) and (3): Z=[CiY.sup.2 /[1+ (1- (1 +Ki)Ci.sup.2 Y.sup.2).sup.1/2 ]]+EiY.sup.4 +FiY 6 +GiY 8 +HiY 10 (1) 2.0< (NAO/NAI)< 7.0 (2) 1.2< r.sub.1 /[(n- 1)f]< 2.1 (3) where, z: distance between aspherical surface and a plane which is perpendicular to optical axis and which passes apex Y: height from optical axis Ci: curvature of apex of i-th aspherical surface (1/r i ) Ki: conical constant of i-th surface Ei to Hi: 4th to 10th order aspherical coefficients of i-th surface NAO: numerical aperture (NA) at object side NAI: numerical aperture (NA) at image side f: focal length d: thickness at lens center n: refractive index of glass.
Inventors
👤 Isao Ishibai
👤 Yutaka Kawai
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-08 16:11
CPC Classifications
G; G02; G02B; G02B3/00; G02B3/02; G02B3/04
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
128 words
A finite conjugation large-aperture lens with aspherical surfaces having aspherical first and second surfaces which meet the condition of the following formula (1) and satisfying the conditions of the following formulae (2) and (3): Z=[CiY.sup.2 /[1+(1+Ki)Ci.sup.2 Y.sup.2).sup.1/2 ]]+EiY.sup.4 +FiY.sup.6 +GiY.sup.8 +HiY.sup.10 ( 1) 2.0<(NAO/NAI)<7.0 (2) 1.2<r.sub.1 /[(n-1)f]<2.1 (3) where, z: distance between aspherical surface and a plane which is perpendicular to optical axis and which passes apex Y: height from optical axis Ci: curvature of apex of i-th aspherical surface (1/r i ) Ki: conical constant of i-th surface Ei to Hi: 4th to 10th order aspherical coefficients of i-th surface NAO: numerical aperture (NA) at object side NAI: numerical aperture (NA) at image side f: focal length d: thickness at lens center n: refractive index of glass.
Claim 2
Dependent Claim
128 words
A finite conjugation large-aperture lens with aspherical surfaces having aspherical first and second surfaces which meet the condition of the following formula (1) and satisfying the conditions of the following formulae (2) and (3): Z=[CiY.sup.2 /[1+(1+Ki)Ci.sup.2 Y.sup.2).sup.1/2 ]]+EiY.sup.4 +FiY.sup.6 +GiY.sup.8 +HiY.sup.10 ( 1) 2.0<(NAO/NAI)<7.0 (2) 1.2<r.sub.1 /[(n-1)f]<2.1 (3) where, z: distance between aspherical surface and a plane which is perpendicular to optical axis and which passes apex Y: height from optical axis Ci: curvature of apex of i-th aspherical surface (1/r i ) Ki: conical constant of i-th surface Ei to Hi: 4th to 10th order aspherical coefficients of i-th surface NAO: numerical aperture (NA) at object side NAI: numerical aperture (NA) at image side f: focal length d: thickness at lens center n: refractive index of glass.
Claim 3
Dependent Claim
29 words
A lens according to claim 1, wherein the lens is made from a glass which has a high refractive index and a glass transformation temperature Tg exceeding 500° C.
Claim 4
Dependent Claim
13 words
A lens according to claim 2, wherein the lens is produced by molding.