SU1682962A1 - Achromatic objective of microscope - Google Patents

Abstract

The invention relates to optical instrument making, namely to the achromatic lenses of microscopes designed to observe transparent preparations in transmitted light in a bright field. The purpose of the invention is to improve the image quality. The lens contains a positive meniscus 1, negative menisci 2, 4 and two convex lenses 3, 5 Magnification 40x, numerical aperture 0.65, field of view 20 mm. 1 il.

Description

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The invention relates to optical instrumentation, namely to the achromatic lenses of microscopes, intended to observe transparent preparations in transmitted light in a bright field.

The purpose of the invention is to improve the image quality.

The drawing shows the principal optical layout of the microscope objective.

The lens is made of three components. The first component is the positive meniscus 1, facing the concavity to the object, the second is the negative meniscus 2 facing the concavity to the image, and the two-convex lens 3, the third is the negative meniscus 4 facing the concavity to the image, and the double-convex lens 5.

The lens has the following main characteristics: Linear magnificationV 40 Aperture A 0.65 Focal length, mmf 5.41 Chromatism of magnification,% HrU -0.74 Lens length, mm, 44 Image size, mm2y 20 Distance from the last surface of the object to the image plane , mm S 212.5 The first positive lens 1 in the form of a meniscus with a concavity facing the object serves to correct spherical and spherochromatic aberrations for a point on the axis.

Installing a negative meniscus 2 behind the first lens 1 provides correction for coma and chromatism.

Installing a second negative meniscus 3 between the two convex lenses 3 and 5 helps to reduce chromatism of magnification, image curvature, and astigmatism.

By placing successively a negative meniscus 4 and a two-convex lens 5, we are able to correct the crying of the image, astigmatism and transverse aberrations of wide inclined beams.

For correction of coma, chromatic aberrations and curvature of the image, positive lenses 1, 3, 5 should be made from the same glass brand with a refractive index of not more than 1.55 and the average dispersion coefficient more than 63, and negative lenses 2, 4 - from the same glass brand a refractive index of more than 1.7 and an average dispersion coefficient of less than 35.

In the above version of the calculation, all positive lenses are made of K8 glass, and all negative lenses are made of TF4 glass. In this case, the coma in the lens only at the edge of the pupil is equal to 0.14%, and at the zone - 0.02%, the image curvature does not exceed 4 mm (in the sagittal section), and 1.26 mm (in the meridional section), the chromatism of magnification over the entire field is 0.7%.

In the calculation variant, the lens objective-achromate microscope has the following aberrations.

The transverse spherical aberration for the main wavelength for a point on the axis is: pupil edge — 0.084 mm, area — 0.0014 mm.

Wave pupil aberration for the main wavelength does not exceed -0.11 A, and in the whole spectral range -0.45 A.

The coefficient of non-isoplanasia: the edge of the pupil is 0.14%, the zone is 0.02%. Increases chromatism across the field.

equal to 0.74%.

Image Curvature and Astigmatism

equal: the edge of the floor at 0.25 mm; zl -1.26 mm;

Zs -3.93 mm; - zl -2.67 mm; area at 0.17 mm; z -0.95 mm; zl -2.02 mm;

zl - zi -1.07 mm.

The mean square wave aberration in terms of spectral interval, field, and pupil is: without defocusing, without distortion - 0.249 A; without defocusing, distortion and curvature of the image 0,244 A.

Claims (1)

Invention Formula five five The achromatic microscope objective, which contains three positive components, the first of which is a single frontal lens, the second contains a negative and two convex lenses, the third contains a negative meniscus facing the concavity of the image, and a two convex lens, characterized in that , the front lens is made in the form of a meniscus with a concavity facing the object, in the second component the negative lens is made in the form of a meniscus turned in concavity to the image, the second and the third component is made of single lenses, while all the positive objective lenses are made of a material with a refractive index of not more than 1.55 and 516829626 the dispersion coefficient is more than 63, and all with a refractive index more than 1.7 and the coefficient-negative lenses are made of a material with dispersion index less than 35.