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Патент USA US2117252

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350-471
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May 10, 1938.
H. w. LEE
, ‘2,111,252
LENSES FOR PH‘OTOG-RAPHY' AND THE LIKE
Filed Dec. 17, .1936
T2565
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Inventor.
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- 2,117,252
UNITED. STATES PATENT OFFICE
2,117,252
LENS FOR. PHOTOGRAPHY AND THE LIKE
Horace William Lee, Chiswick, London, England,
assignor to Kapella Limited, Leicester, Eng
' land, a corporation of England
Application December 17, 1936, Serial No. 116,388
In Great Britain December 18, 1935
3 Claims.
' This invention relates to lenses of the kind
(Cl. 88-57)
comprising two compound meniscus dispersive
nent (that on the shorter conjugate side of the
system) is between 75% and 200% greater than
components with their concave exterior surfaces
that on the concave surface of the front meniscus
facing one another, said components being be
dispersive component.
tween two collective components having surfaces
of different curvatures and having their more
strongly curved surfaces turned outwards, and it
has for its object to provide lenses well corrected
for chromatic aberration, coma, astigmatism and
distortion and better corrected for spherical
aberration than hitherto.
In speci?cation 1,955,591 of patent granted to
me, lenses of the kind referred to‘ are described
in which the concave exterior surface of the rear
dispersive component has a radius greater than
0.3 the focal length of the system, and its convex
exterior surface has a radius greater than 0.4
4 such focal length.
The lens of Lee 1,955,591, while giving extreme
20 ly high de?nition, and, at the same time, being
corrected for distortion, can be improved in re
spect of the correction of residual ' spherical
aberration by the means herein described.
While the aim of lens designers is, for a num
25 ber of reasons, to use lens surfaces with as large
radii as possible consistent with securing the de
sired corrections, I have found in the present case
better results are obtained, especially so far as
'
(2) The point midway between the images of
the front and rear surfaces of the entire system,
in the space on the long conjugate side of the
system, divides the. space between the images of
the concave surfaces of the dispersive elements
in a ratio not exceeding 3:1, counting such spaces
in order from the long conjugate side of the sys
tern.
Three forms of lenses embodying the invention
are shown, by way of example, in the accompany
ing drawing. Figs. 1, 2 and 3 are axial sections of 15
the three forms of construction.
I now give data for the construction of the
three examples, Example I being that shown in
Fig. 1, and so on. The notation is that the suc
cessive radii of curvature, counting from the
front, are called R1, R2, etc., the sign + denoting
that the curve is convex toward the incident
light, and — that it is concave toward the same.
The axial thicknesses of the elements are denoted
by D1, Di, etc., and the separations of the com
ponents by S1, S2, etc.
~
The material is de?ned in terms of the meanv
spherical aberration is concerned, by decreasing refractive index “D, as conventionally employed,
followed by the type number in Messrs. Chance
30 the radii of the opposing concave surfaces of the
compound dispersive components and ‘at the same , Brothers’ optical glass catalogue.’ The Abbe V
number also is ‘given.
time increasing the refractive index of each con
vergent element of such dispersive components
Example I
with respect to its associated divergent element.
35 These changes do not cut down appreciably the.
de?nition of the lens. -
Aperture F/2
‘Equivalent focal length 1.0
In lenses according to the present invention,
the concave exterior surface of the rear dispersive
40 component may have a radius not greater than
0.3 or less than 0.2 the focal length of the system,
and its convex exterior surface may have a radius
not greater than 0.4 or less than 0.25 such focal
length, provided that I use, in each convergent
component of the compound divergent menisci,
glass of a refractive index greater than that in
the divergent component associated with it but
not exceeding it by more than .03.
In lenses according to this invention it is neces
50
sary, in order that they be corrected for dis
tortion, ‘that the following conditions shall be
observed:
(1') The spherical aberration on the concave
55 surface of the rear meniscus dispersive compo
.
Radii
.
Sepa
Thickness.
ration _
l\D
v V
No.
'40
RI + .644
D1 .08
1.61
53.3
610533
R; +2. 650
'
Si
. 005
R: + . 404
D! .146
R4 +2. 267
1.0234
56.2
623562
1.6083
39.6
608390
'
D| .040
45
R5 + . 247
S1
. 20
R0 — .289
-
D4 .040
1.6054
38.0
605880
D5 . 130
1. 6209
57.2
621572
R1 + . 464
'
Rs —- .374
_
S:
. 005
'
R. +1. 789
1
D. .081
R|o—1. 04
.
1.6234
'
50.2
623562
50
2,117,252
Example II
Aperture F/2
Equivalent local length 1.0
-
_ Radii
What is claimed is:
1. A lens system comprising two compound
meniscus dispersive members with their concave
exterior surfaces facing one another, said mem
bers being arranged between two collective mem
bers, all of said members being axially aligned
and air separated from each other, the dispersive
members each comprising a collective element and
a. dispersive element, the collective elements of
Thickness
Sepa-
,,
‘ration
D
V
No.
R1 + .6440
10
D1 .080
R: +2 534
1.61
53.3
610533
D2 .146
1. 6234
56. 2
623562
D; .040
1.6083
39.6
608396
D4 .040
1.6054
38.0
605380
D5
.
1.6209
57.2
621572
member having a radius not greater than 0.3 and
1. 6234
56.2
623562
and its convex exterior'surface a radius not great
er than 0.4 and not less than 0.25 such focal 20
the dispersive members being arranged between 10
their respective dispersive elements and the adja
S1 .005
R1 + . 4011
R4
-
cent collective members, one at least of the col
a
lective members having exterior surfaces of dif-_
ferent curvature and being arranged with the
more strongly curved surface facing outwards. 15
Rl + . 2477
S2
15
. 20
RI — . 2880
R1 + . 5840
'
R! -— .37w
. 130
the concave exterior surface of the rear dispersive '
notless than 0.2 the focal length of the system
S: .005
R9 +1. 670
Dr .081
20 Hui-1.040
length, the refractive index of each collective
element of the compound dispersive members ex
ceeding that of the dispersive element associated
with it but by not more than 0.03.
2. Lenses as claimed in claim 1, in which the 25
Example III
Aperture F/2
..
Radn
'
Equivalent focal length 1.0
Thickness
Sepa
ration
"D
V
spherical aberration ‘on the concave exterior sur
face of the rear meniscus dispersive member is
between ‘75% and 200% greater than that on
the concave surface of the front meniscus ‘dis
No.
R1 + . 6440
Di .08
1.61
53.3
610533
persive member.
R: +2. 421
S1 .005
R! + - 3933
'
D: .146
56. 2
623562
point midway between the images of the front
1. 6083
39. 6
1
608390
1.6054
38.0
605380
1.6209
57. 2
621572
and rear surfaces of the entire system,'in the
space on the long conjugate side of the system, 35
divides the space between the images of the con
cave surfaces of; the dispersive elements in a
ratio not exceeding 3:1, counting such spaces in
1. 6234
R4 —2. 222
D: . 040
3.5
'
R; + . 2469
S2 .20
B: — . 2891
D4 .040
R: + . 7937
'
D5 .130
Ru - .3818
order from the long conjugate side of the system.
S; .005
40 Re +1. 631
Rio —l.040
Do .081
30
3. Lenses as claimed in claim 1, in which the
1. 6234
56. 2
623562
.
40
' HORACE WILLIAM LEE.
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