Optical objective
(proclar)
An optical objective, usable for reproduction as well as for photographic and cinematographic purposes, consists of five components--two on the object side and three on the image side of a diaphragm space--constituted by a total of seven meniscus-shaped lenses all of whose surfaces are concave toward the diaphragm space, the first object-side component and the middle image-side component being negatively refracting doublets. The objective is bodily movable for focusing purposes and its two object-side components are correlatedly axially shiftable to minimize aberrations over a wide range of magnification ratios.
1. An optical objective consisting of a negatively refracting first component, a positively refracting second component, a positively refracting third components, a negatively refracting fourth component and a positively refracting fifth component, said second and third components being separated by a diaphragm space, said first and second components being coupled for correlated codirectional axial shifts at a relatively slow and a relatively fast rate, respectively, to minimize optical aberrations with different magnification ratios.
2. An optical objective consisting of a negatively refracting first component, a positively refracting second component, a positively refracting third component, a negatively refracting fourth component and a positively refracting fifth component, said components being constituted by meniscus-shaped lenses which are bounded by spherically curved surfaces all concave toward an intervening space separating said second and third components,
said first, second, third, fourth and fifth components having respective individual focal lengths whose absolute magnitudes are related to one another in the ratio of substantially 7.5:1.1:2.7:9.7:1.6.
3. An objective as defined in claim 1 or 2 wherein said first component is a doublet consisting of a positive lens L1 and a negative lens L2, said second and third components being single lenses L3 and L4, said fourth component being a doublet consisting of a negative lens L5 and a positive lens L6, said first component being a single lens L7.
4. An objective as defined in claim 3 wherein said lenses L1 to L7 have radii r1 to r12 and thicknesses and separations d1 to d11 whose numerical values, based upon a value of unity for the overall focal length of the objective, together with their refractive indices ne and their Abbe numbers νe are substantially as given in the following table:
| ______________________________________ |
| thicknesses lenses radii and separations ne ν e |
| ______________________________________ |
r1 = +0.31 L1 d1 = 0.11 1.63 57 r2 = +7.78 L2 d2 = 0.08 1.58 41 r3 = +0.21 d3 = 0.03 r4 = +0.31 L3 d4 = 0.03 1.69 48 r5 = +0.50 d5 = 0.12 r6 = -0.91 L4 d6 = 0.02 1.69 48 r7 = -0.62 d7 = 0.03 r8 = -0.18 L5 d8 = 0.03 1.63 35 r9 = -1.24 L6 d9 = 0.06 1.67 48 r10 = -0.23 d10 = 0.03 r11 = -1.10 L7 d11 = 0.03 1.62 60 r12 = -0.54 |
| ______________________________________ |
.
5. An objective as defined in claim 2, usable for photographic reproductions, wherein said first and second components are coupled for correlated codirectional axial shifts at a relatively slow and a relatively fast rate, respectively, to minimize optical aberrations with different magnification ratios.
6. An objective as defined in claim 4 wherein said first and second components are correlatedly shiftable to vary their air spaces d3 and d5 in opposite senses by up to about 0.015 times said overall focal length.
My present invention relates to an optical objective adapted to be used for reproduction of documents or the like as well as for photographic and cinematographic purposes.
A known reproduction objective consists of two front components and three rear components separated by an intervening diaphragm space, i.e. a negatively refracting first component and a positively refracting second component on the object side and a positively refracting third component, a negatively refracting fourth component and a positively refracting fifth component on the image side of that space. The two negatively refracting components may be doublets, each composed of two lenses of opposite refractivity, while the others are singlets.
In such an objective it is important to provide satisfactory correction of optical abberrations over the entire field of view, at least for a particular magnification ratio with which it is to be used. When this ratio is subject to variation, the requirements become more stringent.
The object of my present invention, therefore, is to provide an optical objective of this type which can be used over a wide range of magnification ratios with a relatively large aperture, preferably as high as 1:3.5.
In accordance with one aspect of my present invention, the constituent lenses of a five-component objective as described above are so dimensioned that their individual focal lengths have absolute magnitudes which, progressing from the first to the fifth component, are related to one another in the ratio of substantially 7.5:1.1:2.7:9.7:1.6, each lens being bounded by spherically curved surfaces which are concave toward the diaphragm space. These individual focal lengths may also be expressed, in terms of the overall focal length F of the objective, by f I ≉-7.5F, f II ≉+1.1F, f III ≉+2.7F, f IV ≉-9.7F, f V ≉+1.6F.
I have found that such an objective, which is bodily movable for focusing purposes between the object plane and the image plane of a reproduction camera, is well corrected for a certain magnification ratio, e.g. of about 1:5, as determined by the positions of these planes in relation to the focal points of the objective. With other magnification ratios above and below this value, however, distortions are encountered which can be corrected, pursuant to a further feature of my invention, by axially shifting the first and second components at different rates but in a correlated manner. More particularly, these components are to be displaced codirectionally, with the first component moving more slowly than the second. Such correlated shifting, pursuant to my invention, could also be used in a differently dimensioned objective of this general type.
No comments:
Post a Comment
The most important thing to remember about the Comment Rules is this:
The determination of whether any comment is in compliance is at the sole discretion of this blog’s owner.
Comments on this blog may be blocked or deleted at any time.
Fair people are getting fair reply. Spam and useless crap and filthy comments / scrapers / observations goes all directly to My Private HELL without even appearing in public !!!
The fact that a comment is permitted in no way constitutes an endorsement of any view expressed, fact alleged, or link provided in that comment by the administrator of this site.
This means that there may be a delay between the submission and the eventual appearance of your comment.
Requiring blog comments to obey well-defined rules does not infringe on the free speech of commenters.
Resisting the tide of post-modernity may be difficult, but I will attempt it anyway.
Your choice.........Live or DIE.
That indeed is where your liberty lies.
Note: Only a member of this blog may post a comment.