DD292552A5 - TWO-PIECE COLOR-ERROR-FREE PLANACHROMAT - Google Patents

Abstract

The invention comprises a two-part color defect-free planachrome for tube length infinite, which is corrected for the entire visible and adjacent IR spectral range. The invention is particularly suitable for Meszzwecke in optical precision tools with high-resolution recording materials. By Überberrezung of the front positive system part and Verknuepfung with a corresponding rear part of the system as an inverse achromatic Kittglied, as well as the use of a certain type of heavy shotguns in addition to the known use of Fluszspat or fluszspataehnlichen materials for the lenses, is a high-resolution, low producible lens . {realized optics; Lens; optical system; achromatic; Planachromat; Microscope objective; Meszobjektiv; Fluszspatobjektiv; CVD-free system; Tube length, infinite}

Description

field of use

The invention is a microscope objective for normal field for the entire visible and adjacent IR spectral range, in particular for measurement purposes with high-resolution recording materials.

Characteristic of the known state of the art

In the recent times, numerous plan apochromats and achromats have been developed that are CVD-free and calculated for tube length °° and whose secondary spectrum is low. However, these excellent corrections are only guaranteed for a limited range of wavelengths adapted to visual observation within the depth of field. The known stronger systems have residual chromatic aberrations over the entire field and the definition brightnesses of the field points are already decreasing at the border regions of the visible spectrum. In addition, these systems are complicated and expensive and extreme special glasses or crystals are used.

The following general construction principles for such extremely corrected optical systems are known:

By overcorrection of a front positive part of the system and linking with a corresponding rear part of the system as an inverse "achromatic" cemented glass with flint glass in the positive lens and crown glass in the negative lens, the difference in the angles for the blue and red color is eliminated.

- For the apochromatic correction two mirror-image cemented components have been used, each of which consists of cementing a collecting lens of high refractive power, for. Example of fluorspar or fluorspar material, and a diverging lens made of a glass with high dispersion.

For Bildfeldebung it is known to use in such optical systems as a front member a thick positive meniscus of high refractive heavy fluid.

Thereupon numerous Pflanapochromate and achromats are based, which are all afflicted with the disadvantages mentioned in the beginning.

Object of the invention

The invention has a plan achromatic target, which is simple in construction, consists of inexpensive materials and which is used and corrected in the entire visual and adjacent IR spectral region and is suitable for high-precision measurement purposes.

Explanation of the essence of the invention

The object of the invention is to provide a high-resolution Planachromaten, which has no color aberration in the wavelength range of 400 to 800nm. In addition, infinite image size, small diameter of the components, large object distance, and in conjunction with the tube lens telecentricity for the pupil position to ensure. This object is achieved according to the invention a two-part, chromatic aberration Planachromat for «tube length by object side the first part beginning with thick positive meniscus from hochbrennendem Schwerflint as a front lens and further containing two zweilinsige Kittgruppen, facing concatenation of CaF ₂ or Flußspatähnlichem glass and their diverging lenses made of heavy flint and with a final rear part of the system as an inverse achromatic cemented with Schwerflinkt in dsr condenser lens and crown glass in the diverging lens and further characterized in that between the converging lenses of the cemented a thick converging lens of CaF ₂ or flux-like glass is arranged and that the Front lens, the diverging lenses of the two cemented components and the converging lens of the rear part of the system consist of the same or similar Schwerflint whose value ΔΡ, g, F = +0,012 ± 0,002, the deviation of the relative partial dispersions ion from the normal line and that the rear system part final diverging lens has a value APg, F '= 0 ± 0.006, an η, value = 1.46 ± 0.03 and a V _e = 67 ± 2. The essence of the invention is that in addition to the favorable for apochromatic correction material combinations of fluorspar and heavy guns a compensation member is used, which is arranged with a larger air gap, which affects above all the chromatic magnification difference, according to the front system. The front system generates its exit pupil in front of the composer whose first frame edge can thus serve as an aperture diaphragm. With this diaphragm position can be corrected by the selected shape of the Kompensgliedes the distortion and exert favorable influence on coma and astigmatism correction.

This necessary form of Kompensgliedes, namely thick converging lens and thinnest diverging lens, according to the invention leads to a complete compensation of the secondary spectrum for all wavelengths from 400 to 800 nm, when the thick converging lens consists of the same material as the diverging lenses of the front part. In this case, the effects of partial dispersion of the material just cancel out, with the small partial dispersions of the flux latex of the front part, which produces the collecting effect of the entire system, being compensated by the greater partial dispersion of the dispersing lens of the compensating member. In this way, a super-achromatic correction is achieved, without having to resort to several complicated optical media, which would only produce several inflection points in the longitudinal color correction from 400 to 800 nm. Due to the main compensation of the remainder of the secondary spectrum with a simple heavy flint glass, this can be used with the highest possible refractive index (as far as the transmission permits), which is important for the correction of the Petzval sum (1st lens of the front part and 1st lens of the compensation element) Bildfcldebnung, while with the choice of a high basic dispersion (small Abbe number v) is done with little lenses or links of the overall system to obtain the smallest possible diameter, to ensure high transmission and to produce little stray light. According to the invention, the front system consists of a minimum number of lenses

by the consequence Einzellinse Kittglled from 2 lens single-lens cemented compound of 2 lenses, wherein the first lens from the above-mentioned sword lint for correcting the chromatic difference in magnification, the two cemented carbide components from Schwerflint and Flußspat or Flußspatähnlichem glass and the second Einzellinse also consist of fluorspar or flußspatähnlichem glass. The inventive design of the compensation element with the same heavy flint makes it possible to carry out the front part of the optical system as a combination of heavy flint and fluorspar, which thereby achieves the desired image performance with the stated lowest number of lenses. Since each optically acting outer surface has several functions to ei lullen, Rieh also results in a favorable shape design for reflections in reflected light illumination beam path by no surface is concentric or concentric with the optical path of the object or the pupil in approximation.

embodiment

The invention will be explained in more detail with two exemplary embodiment with reference to two drawings.

Figs. 1 and 2 show lens sectional images of the planachrome according to the invention.

The general, inventive structure of the two embodiments s. Figs. 1 and 2 are the same, the different construction data are included in the accompanying Tables 1 and 2. In addition to the lenses shown in FIGS. 1 and 2, the tables also indicate the parameters for a suitable 6-lens tube lens in the tables. The tube lenses are to be constructed in a manner known per se, in the table these lenses are marked T).

Corresponding to FIGS. 1 and 2, lenses L _t to L ₈ are arranged along an optical axis OO '. The lenses are uniquely identified according to the corresponding tables 1 + 2 with the design data by their radii of curvature r " their crest thicknesses d, and the indication of their materials. Air gaps between the lens vertices are denoted by I. The numbering takes place consecutively from the object side O to the image side 0 ', and the length specifications are given in mm.

Table 3 shows the essential performance parameters of the two embodiments 1 and 2. 3 shows the corresponding positions of the adjustment planes as a function of the wavelengths, where T = 0.000546 mm (aperture) ^{2 is} a measure of the depth of focus.

Appropriately, in the choice of the focal lengths of the individual lenses or members and the deflection of the residual error of the tube lens used for use, because only so the optical system lens tube lens can produce both the desired magnification between object and receiver as well as the distance The tube lens of the object, the pupillary center are made in correction of the off-axis image fields, the correction of the distance of the tube lens from the lens is affected.

The specified embodiments can be adapted to other Tubuslinsen by small changes in the radii and distances, also there is the possibility to perform the adaptation to a theoretically ideally corrected Tubuslinse. According to the requirements of the particular use of the lens type proposed, it can be used with a similar structure and optical media for lenses of apertures 0.3 and 0.6, with the image-side conditions being the same, i. same size image field and image error correction. As a result of the simple design of the objectives according to the invention and of the simple optical media, they are easy to reproduce and can be produced economically. Their performance parameters are widely used in many measuring instruments, some methods can only work effectively by the use of lenses in which all wavelengths between 400 and 800 nm are sharply imaged by automatic focusing, the field correction is adapted to electronic receivers and no detail distortion occur.

Table 3

(all values are related to the same recording level)

λ / nm a (Figure 1 / Table 1) y '= 8 chr.V.Diff. b (Figure 2 / Table 2) y '= 8 chr.V.Diff. definition brightness 0.732 + 0.10% definition brightness 0.720 + 0.11% y '= 0 0.819 + 0.04% y '= 0 .8913 + 0.07% 404.7 0.885 0.848 +0.01% 0,792 0.918 + 0.02% 435.8 0.993 0,874 reference 0.982 0.956 reference 480.0 0.995 0.908 + 0.03% 0.978 0.960 -0.01% 546.1 0.995 0.914 + 0.06% 0.997 0.930 -0.008% 643.8 0.998 0,864 + 0.09% 0,975 0.929 0 706.5 0.996 0,794 + 0.12% 0.939 0.913 + 0.003% 768.2 0.960 0.931 825.0 0.897 0.910

Claims (3)

claims: 1. Two-part, chromatic aberration free plan achromat for °° tube length, object side the first part starting with a thick positive meniscus of high-refractive heavy flint as the front lens and further containing two zweilinsige Kittgrüppen whose facing converging lenses of CaF ₂ or Flußspatähnlichem glass and their diverging lenses made of heavy flint and with a final rear part of the system as an inverse achromatic cemented with Schwerflint in the condenser lens and crown glass in the diverging lens, characterized in that between the converging lenses (L ₃ , L ₅ ) of the cemented components a thick converging lens (U) of CaF ₂ or Flußspatähnlichem glass is arranged and that the front lens (L ₁ ), the diverging lenses (L ₂ , L ₆ ) of the two cemented members and the converging lens (L ₇ ) of the rear system part of the same or similar Schwerflint whose value APg, F '= +0.012 ± 0.002, the deviation of the relative partial dispersion of the straight line denotes, and in that the diverging lens (Le) e terminating the rear part of the system e values ΔP g, F '= 0 ± 0.006, a Πβ value = 1.46 ± 0.03 and a V _e value = 67 ± 2 plat. 2. Two-piece, color defect-free Planachromat according to claim 1, characterized by the following concrete design data: Table 1 (Figure 1) Planar Rozzle 13x / 0.3 lens surface 1.76861 26.31 L, 3 4 L ₂
L ₃ 29.5320 2.4900 CAF 2 1.79192
1.43496 L ₄ L ₅
L ₆ L ₇
L ₈ 6 7 8 9 10 11 12 13 14 1.43496
1.76861 1.76861
1.46619 1.43496 94.56 Continuation of Table 1 (Figure 1) Planar Roughness 13x / 0.3 Lens Area Radius j i Π Distances materials dj / l tube lens: 15 16 17 18 20 21 22 23 24 25 1,000 E + 20 1,000 E + 20 1,000 E + 20,863,1000 211.1100 -257.7300 257.7300 -211.1100 -863.1000 1,000 E + 1,000 E + = 50,0000 air 25.0000 SF 8 = 115.5700 air 4.7000 SF10 5,3000 BALF = 24.5600 air 5,3000 BALF 4.7000 SF10 1 = 10,0000 air 10,0000 BK 6 air 3. Two-piece, color defect-free plano-chromatograph according to claim 1, characterized by the following concrete design data: Continuation of Table 2 (Fig. 2) Plan achromat 26x / 0,6 ν Lens area radius j i Π Distances materials L ₇
L ₈ 8 9 11 12 13 14 T ₁ T ₂
T ₃ tube lens: 15 16 17 18 19 20 21 22 23 24 T ₆ 25,000 E + For this 2 pages drawings T ₄
T ₅ 10,000 BK 7 1.43496 94.56 1.43496 94.56 1.76861 26.31 1,76861 26,31 1,46619 65,47