Патент USA US2405729код для вставки
bis-arch Room 2,405,729 Patented Aug. 13, 1946 UNITED STATES PATENT OFFICE 2,405,729 FOUR-COMPONENT OBJECTIVE Fred E. Altman. Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application November 20, 1943, Serial No. 511,060 1 14 Claims. (CI. 88-57) 2 This invention relates to four component ob jective lenses. thereby producing sharp de?nition on the axis. The improvement is far beyond anything pre viously thought to be obtainable, the nearest pre An object of my invention is to provide an objective with critically sharp de?nition at the axis, especially when used at ?nite conjugates, vious approach being with another type of lens as described in my Patent 1,880,394. Some of these features also further reduce the Petzval and with a reduced Petzval sum. A particular object of my invention is to pro sum. vide an objective suitable for use as a relay lens The zonal spherical aberration may be cor rected by the most preferred shape of compo in an optical sighting device. nents, without making any components compound An object of a preferred feature of my inven 10 or by making them compound and with less spe tion is to provide a relay lens with a negative ci?c designation of the shape, or again by mak Petzval sum and suitable for use in sighting de ing them compound and with the preferred fea vices according to my copending application, Se ture of high index elements and with still less rial No. 511,062, ?led concurrently herewith. speci?c designation of the shapes of the com By ?relay lens? is meant an objective lens with 15 ponents. real object and image at ?nite conjugates and The series of features relating to arrangement without any intermediate real images, the "real and shape, some of which include some or all object? being an image formed by another lens of the preceding features in the series, are as or other lenses in front of the relay lens. The follows: One, the two negative components are expression "real object and image" is used in a 20 between the two positive components. Two, the strictly technical sense meaning an object in front of the front surface and an image behind the rear surface of the relay lens, and may in clude an object or image which is virtual with respect to the adjacent part of the whole optical 25 system. Heretofore, relay lenses have usually been made of one or more cemented achromats, the larger the aperture ratio speci?ed, the greater the num ber of components required so as to keep the zonal spherical aberration within the tolerance per mitted by the requirement for a sharp image at the center of the ?eld of view. The demand for sighting devices with a ?atter image and less astigmatism in the ?eld zones away from the axis has led to the proposal of several expedients all of which have drawbacks which have kept them from being generally adopted. However, the present invention over comes all objections and provides a lens ideally suited to this purpose. The present invention is an improvement in the type of objective which is made up of two negative components and two positive compo nents in axial alignment forming two halves of the objective, each half consisting of a negative component and a positive component spaced apart by between 0.02)? and 0.5} where f is the focal length of the half. This arrangement reduces the Petzval sum of the objective in known man ner. When used at unit magni?cation, the sys outer surface of each component is of the same sign as that of the whole component, that is, concave in the negative and convex in the posi tive components. By outer surface is meant the surface farther from the other half of the ob jective. Three. the negative components are bi concave and the positive components biconvex. Four, the outer surface of each biconcave com ponent is more strongly curved than the inner And ?ve, the radius of curvature of the outer surface of each biconcave component is between 0.08 and 0.50 times that of the surface facing toward the other half of the objective. The necessity for these features depends on the 35 degree to which other features are present. The series of features relating to the compound ing of the components is similarly as follows: One, at least one component in each half is compound and consists of a negative element fac 40 ing toward the other half of the objective and a positive element cemented thereto. Two, the positive element has a higher index than the neg ative element. Three, at least one component in each half is compound and consists of a negative 45 element cemented to a positive element of higher refractive index in such a way that the cemented surface is convex toward the other half and has positive power. It will be noted that the third feature includes the ?rst two necessarily, that is since the negative element has lower index it must face toward the other half if the cemented tem is preferably symmetrical. surface is to be convex toward the other half and The invention includes features relating to the have positive power. Four, the component which arrangement and shape of the components, oth is compounded in this manner is speci?cally the ers relating to the compounding of components, negative component in each half. Five, all four and still others relating to the indices of refrac components are compound, at least one in each tion of the elements, all of these features oper half of the objective being according to the ?rst ating to reduce the zonal spherical aberration and 30 surface. two features of this series. And six, all four 2,405,720 3 , components are compound, at least one in each half being according to the third feature of this series. As with the shape features, the necessity Hamymm? for these depends on whether or not certain other Len, elements ND v Imdw_____ __ 1,611 574 features are present. '4 Example 3, Fig. 1 5 The features relating to the indices of refrac- EF'm? "7'0 Rad? tion of the elements of compound components are: One, the positive element has an index greater than 1.64. This index can be as high as H and m ?? " 1' m 33'8 glasses are available. At present this is about 10 2.1. Two, all the elements of the objective have refractive indices greater than 1.6. And three, BB1! mm!? the positive elements in components according to at least the first feature relating to the manner Lem elements of compounding have refractive indices greater 15 I dm Pt?+'鞍�Thickness +R,__ 15-29;, ?H-415 -g1-+R1-51.a 81-81-35 5.3:335533 ?$217,238 Example 4, F193} ?M14 "-100; "7-0 Pip-11� m ND v 1,? 45 8 Rm R__R ?40 T we? ht do, than 1.7. The most preferred embodiment, of lllgnd vnIIIII 11720 2013 iRz?ii-?areii-lg� course, has all features of all three sets just listed. m and VI_____ 1_ 617 3? _R?_+fe,_29 3 ;,-t:-3j3 1v sndV .... -_ +R|??R0-29.3 awn-4.1 +R"_R"75?2 S"12'2 By means of the feature of positive elements 1.020 00.3 with index greater than 1.?? combined with at least the second feature of each of the other se- 20 sie-A'g-glg . ries, I have succeeded in designing an objective Example 51 Flg- 3 with Petzval sum reduced to a negative value. Such a lens is particularly suitable for use in H], mm a m sighting systems according to my copending ap- Lens elements EF-m. ' ND "m v Radii plication mentioned above. 25 It is advantageous that the two halves of the land 1.744 45.8 objective be spaced apart by between 0.04 F and F 11 and VII----- 1- 12� 29-3 where F is the focal length of the whole objecm and 1.017 30.0 tive. Observing the lower limit aidsin ?attening IV "I"---- -- W0 60-3 the ?eld, while an upper limit is necessary if 30 vignetting is to be avoided. If a prism 01- ?lter glass is to be included in the system, the central space of this relay lens is a convenient place for it because the bundles of rays are parallel or Half system: nearly parallel. If a prism or ?lter is included, 85 Le!? eliiments Pt __m26 z Thickness +R\-?Ru-33.0 n-a-za jglf?gfm? 51-5113; ?R4-+Ro'29.3 $333133 awe-3.1 "5:53;: Example 6? Figs? 5 and 6 00.7 Ptz??.0007 EF-lOO; ND V Rad? Thickm? the effective separation is taken as the path length in the prism or ?lter divided by the refrac- 1 "1d V1 ----- -- 1- 617 55-0 tlj閍jllgjg-g tive index plus the sum of the air-spaces. 11 andV_____ __ 1.007 50.1 -R.-+R.-z0'0 a-n-1I7 n1end1v~~~ 1- ?17 3&5 Qi??j?Lj�-� ?521-031 It is preferred that the objective be symmetrical and corrected for unit magni?cation, but 40 gfgf-szg ' the invention is not limited to this form. ' . In the accompanying drawings: Example 7, Fig. 5 Figs. 1 and 2 show a relay lens consisting of Halfsystem: four simple components. Figs. 3 and 4 show a relay lens consisting of 45 Lemelemen" four compound components. Figs. 5 and 6 show a relay lens consisting of two simple and two compound components. Figs. 7 and 8 show a symmetrical relay lens with a prism in the central space. 50 The data shown in Figs. 2, 4, 6, and 8 is re- v5.0 N� Ptz--.0Ol4 v Rad? ?adv!----- -- L611 5? nmdv _____ __ 1,697 Tum?! +Ё-?R""3皛7 """m 50.1 ? "Ha-72.3 ?R|-+R|-2l.7 s,-s,-11.7 a-il-eo mmd 1v~---- ?17 3? +?R?R?_?_?*;�'1;&� "El-?g i Example 8? F 98' 7 ?I 8 peated here along with additional examples In each case the unit of length may be taken to be a EF-lOO; Half system: EF-IOO; fl7.8 Ptz?+.0009 millimeter, and each example is given on the scale of 100 units focal length to facilitate comparisons. 55 Lem element! Example 1? F 198' 1 am? mm? Lensolemeuts - H ?鞍' No m V Ptz=+00008 ' Radii Thickness 60 N� V Rid" Thick?! rendrv ..... -- 1.611 57.2 +R1-?Rn-+28.15 a-a-aos lIandIII P... 1.040 ass :g::I�:-:&g Here-+12? 822731?; Sea-s: _______ n . ' \ , The following table shows details of the ex Imdw----- -- 1- 611 57-? 11 and 1. 040 33.8 iggggggg 53-3333; amples embodying features of the invention. ?R;-+Re-24.4 17-11-10 Other features are obvious from the drawings and +R?"R"m-5 8"?? 65 the above tables. Example 2, Fig. 1 Half system: lenselements EF-lOO; Np? . 117.0 V . Example N0. Ptz-+0.00191 RBI!!! R -?R -27.1 1v Thidmw 7-1-4 7 70 F ___________ __ 131 genpgn .... -- 0.43 2 no 0.25 3 4 6 6 7 355 0.20 109 0.11 105 0.13 m 0.20 108 0.15 8 m 0.44 . Imdw 1 611 57 2 ig;-+R;-g�.3 sf-gLgg on?? ----- -- 0.20 0.30 0.10 2.: 8.; 0;: (to: 0.20 nmd L617 36.6 1821-2127911 t15:11:11 Evian-1:131? ifiii' i.'6ii'1.t17 1.017 1:017 1:011 'ifBii vvulvll nuw? 2,405,729 In this table ?F? is the focal length of the whole relay lens, ?Separ." designates the e?'ective sep aration of the two halves as previously de?ned, 6 ponents in axial alignment forming two halves which are effectively spaced apart by between "Inner R and Outer R" mean the absolute values 0.04 F and F where F is the focal length of the objective, each half consisting of a biconcave of the radii of curvature of inner and outer glass air surfaces respectively of the biconcave com ponents, ?Np? and "NN? are the respective refrac tive and a biconvex component spaced therefrom tive indices of a positive element and a negative element which are cemented together, the largest component facing the other half of the objec by between 0.02 f and 0.5 f where j is the focal length of the half, characterized by the radius of curvature of that surface of each biconcave such difference in index being indicated, and the 10 component which faces the biconvex component lowest N is shown to indicate the preferred fea being less than that of the surface which faces ture of all the refractive indices being greater the other half of the objective and by one com than 1.60. ponent in each half being compound and consist The half system focal length is given in the ing of a negative element facing toward the other drawings for more accurate comparison with the 15 half of the objective and a positive element with prior art and between examples. It will be noted higher refractive index cemented thereto. that except for Example 2, the whole lens has 5. A lens according to claim 4 in which the larger focal length, i. e., less power than either refractive index of said positive element is greater half alone. The fact that these examples are than 1.64. , symmetrical and work at unit magni?cation 20 6. A lens according to claim 4 in which all means that the light between the halves is col four components are compound. limated and hence that the center space is not 7. A symmetrical objective lens consisting of very critical and in turn that the whole lens focal four components in axial alignment forming two length may be varied (by changing the central equal halves which are effectively spaced apart space) without materially affecting the correc 25 by between 0.04 F and F where F is the focal tions. Hence, the half system focal length is the length of the objective, each of the equal halves critical one relative to correction of aberrations. consisting of a biconcave component and a bi convex component, the biconcave component be of the invention, I wish to point out that correc ing nearer the other half, characterized by at tion, and ultimately over-correction, of Petzval 30 least one component in each half being compound sum in a lens of this type is best obtained by and consisting of a negative element cemented to - separating the elements or components as much a positive element of higher refractive index and as possible in each half consistent, of course, with by the cemented surface being convex toward the tolerable vignetting of the oblique pencils of light. other half and having positive power. Secondly, the collective components should have 8. An objective lens consisting of four com as high an index of refraction as possible, and the ponents in axial alignment forming two halves negative components should have as low an index which are effectively spaced apart by between as is permissible consistent with the correction 0.04 F and F where F is the focal length of the of spherical aberration. To assist in the correc objective, each half consisting of a negative com tion of spherical aberration and to permit a cer 40 ponent facing the other half of the objective and tain amount of the color correction to be pro a positive component spaced therefrom by be vided in each component separately. the prefer tween 0.02 I and 0.5 f where f is the focal length able form of the invention has each component of the half, that surface of each component which compound. That is, the correction of color be faces away from the other half being of the same came increasingly dimcult with increased spac sign as the whole component, characterized by ing and the lowering of the index in the nega each negative component being compound and tive component, but this was best solved by mak consisting of a negative element facing the other ing the negative components compound and hy half and a positive element with higher refrac perchromatic. tive index cemented thereto. The characteristic features of my invention are 9. A lens according to claim 8 in which the By way of review of the fundamental theory best described by the accompanying claims. said positive element of each negative component ' What I claim and desire to secure by Letters Patent of the United States is: 1. An objective lens consisting of four com has a refractive index greater than 1.64. 10. An objective lens comprising four com ponents in axial alignment forming two halves which are optically spaced apart by between 0.04 F and F where F is the focal length of the objec ponents in axial alignment forming two halves which are effectively spaced apart by between 0.04 F and F where F is the focal length of the objec tive, each half consisting of a negative com tive, each half consisting of a biconcave com ponent facing the other half and a positive com ponent and a biconvex component spaced apart ponent spaced therefrom by between 0.02 f and by between 0.02 f and 0.5 f where f is the focal 0.5 f where f is the focal length of the half, that length of the half, the biconcave component fac surface of each component which faces away from ing the other half of the lens, characterized by the other half being of the same sign as the the radius of curvature of that surface of each whole component, characterized by having all biconcave component which faces the biconvex the four components compound each including a component being between 0.08 and 0.50 times positive and a negative element and by two com that of the surface which faces the other half ponents of like sign being cemented doublets, of the objective. each consisting of a negative element facing the 2. A lens according to claim 1 which is sym other half of the objective and a positive element metrical with respect to the central space. of higher index cemented thereto. 3. A lens according to claim 1 in which at least 70 11. An objective according to claim 10 in which one component in each half is compound and the positive element of each of the said two consists of a negative element facing toward the cemented doublets has a refractive index greater other half of the objective and a positive element than 1.7 and a dispersive index greater than 35. with higher refractive index cemented thereto. 12. An objective lens comprising two dispersive 4. An objective lens consisting of four com doublets spaced between two collective doublets, 8,405,729 7 the central space being less than F and the outer two spaces being less than 0.5 F, where F is the focal length of the objective, each doublet con sisting of a negative element cemented to a posi tive element, in which the positive elements of the outer components are biconvex, face outward, and have a higher refractive index than that of 8 tween 0.02 I and 0.5 f where f is the focal length of the half, that surface of each component which faces away from the other half being of the same sign as the whole component, characterized by at least one component in each half being a cement ed doublet consisting of a positive element with refractive index greater than 1.7 facing away from the other half of the ?objective and a nega 13. An objective lens consisting of four com tive element with refractive index less than that ponents in axial alignment forming two halves 10 of the positive element. which are effectively spaced apart by between 14. A lens according to claim 13 for use as a 0.04 F and F where F is the focal length of the relay lens in a sighting device and having a nega objective, each half consisting of a negative com tive Petzval sum. ponent facing the other half of the objective and a positive component spaced therefrom by be 15 the negative components cemented thereto.