RU2532959C1 - High-magnification plan-apochromatic high-aperture microlens - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: microlens comprises five components. The first component comprises a meniscus whose convex side faces the image space and a positive lens glued from a negative meniscus facing the image space with its convex side and placed in front of said first meniscus. The second component consists of two positive lenses, the first being glued from a positive and a negative meniscus, facing the image space with their convex sides, and the second being a biconvex lens and a negative meniscus, facing the image space with its convex side. The third component is glued from a negative meniscus, facing the image space with its concave side, and a biconvex lens, and an additional biconvex lens in front. The fourth component comprises a separate positive meniscus facing the image space with its concave side, and a lens glued from a positive and a negative lens. The fifth component includes a lens glued from two menisci facing the object space with their concave side, and in front of said lens, a separate meniscus facing the object space with its concave side.

EFFECT: larger linear image field and entrance numerical aperture, improved mono and chromatic aberrations of axial and off-axis beams.

2 cl, 1 dwg, 1 tbl, 1 app

Description

The present invention relates to optical instrumentation, namely, microscope lenses, and can be used for visual observation and photographing of low-contrast microscopic structures that are at the limit of the resolution of light microscopes in natural light, visible luminescence light, in polarized light by the bright field, dark field method , phase contrast, etc.

A known apochromatic microscope objective [1], containing five components, the first of which is a positive meniscus facing concavity into the space of the object, the second is a double-glued positive lens, the third component is a three-glued positive lens, the fourth component contains two glued positive lenses and the fifth is a negative meniscus .

The lens has an apochromatic correction for a point on the axis, a high input aperture, but an insufficient image field (20 mm), residual astigmatism and image curvature, which do not allow simultaneous observation of the entire image field, as well as a 160 mm tube.

The closest technical solution to the claimed invention is a high aperture achromatic micro lens of large magnification [2]. It contains five components, the first of which is a positive meniscus convex to the image space, the second is made in the form of two positive menisci convex to the image space, the third component is glued from the positive and negative lenses, the fourth contains a positive biconvex lens and gluing from the positive and negative lenses, the fifth - negative meniscus, facing concavity to the space of images, glued from the positive and negative lenses.

The lens has a rather high input aperture (63 × 1.15), but not sufficiently high point correction on the axis and in the field, large chromaticity of magnification (0.8%), residual astigmatism and curvature, and insufficient linear image field (20 mm).

Modern models of microscopes require a high-aperture plano-chromatic micro-lenses, which have improved correction of monochromatic and chromatic aberrations on the axis and the entire image field.

The main task to which the invention is directed is to increase the linear field of the image and the input numerical aperture, to improve the mono and chromatic aberrations of the axial and off-axis beams.

The problem is solved using the proposed planochromatic high-aperture micro lens of large magnification, which, like the prototype, contains five components in series, the first of which is made in the form of a meniscus, convex to the image space, the second, consisting of two positive lenses, the third, glued from two lenses, a fourth containing a single positive and glued from a positive and negative lens, and a fifth component including a double-glued lens, consisting of positive and negative lenses.

In contrast to the prototype, the first component is glued from a negative meniscus convex to the image space and an additional positive lens placed in front of the meniscus, the positive lenses of the second component are glued, the first from the positive and negative meniscuses convex into the image space, and the second - from a biconvex positive lens and a negative meniscus convex to the image space, the third glued component consists of a negative meniscus turned concave into the image space and a positive biconvex lens, and in front of it is placed a positive biconvex lens, in the fourth component a single positive lens is made in the form of a meniscus turned concavity into the image space, and the double-glued lens of the fifth component is made of two menisci, facing concavity into the space of the object, and in front of it is additionally placed a single meniscus facing concavity into the space of the object.

In addition, the refractive indices of the negative meniscus of the first component, negative menisci of the second component, the negative lens in the gluing of the fourth component and the negative meniscus of gluing the fifth component are 1.78≤n _d ≤1.85, and their dispersion coefficients are 40≤ν _d ≤47, the refractive indices of the negative the meniscus in gluing the third component and the positive meniscus in gluing the fifth component have values 1.8≤n _d ≤1.85, and their dispersion coefficients are 22≤n _d ≤25.

The essence of the invention lies in the fact that the implementation of the first and second components is bifurcated, the third - glued from a negative meniscus and a positive biconvex lens, and the placement of a positive biconvex lens in front of it, the placement of an additional negative meniscus before gluing in the fifth component, as well as the configuration of the lenses, allowed provide planned correction, and the choice of glasses with the above refractive indices and dispersion coefficients allowed us to achieve apochromatic orrektsii and increase the input numerical aperture from 1.15 to 1.2.

Based on the foregoing, we can conclude that the new set of essential features of the claimed invention allowed us to obtain a technical result consisting in achieving planochromatic correction, due to which the entire field of view with high contrast is simultaneously observed, to increase the linear field of the image by 1.25 times and the input aperture to 1.2.

The proposed planochromatic high-aperture micro lens of large magnification is illustrated by the drawing, in which Fig. 1 shows its optical scheme, as well as by the Appendix, which gives the design parameters and aberration releases.

The inventive planachromatic high-aperture high-magnification micro lens contains five components.

The first component I contains a negative meniscus 1, convex in the image space, in front of which is additionally placed a positive lens 2, which is glued to the meniscus 1.

The second component II consists of two positive lenses, the first of which is the gluing of the positive 3 and negative 4 menisci convex into the image space, the second is glued from the positive biconvex lens 5 and the negative meniscus 6 convex into the image space.

The third component III contains a negative meniscus 7, turned concavity into the image space, glued with a positive biconvex lens 8, and in front of it is additionally placed a positive biconvex lens 9.

The fourth component IV contains a single positive lens 10 made in the form of a meniscus facing concavity into the image space, and glued from a positive biconvex 11 and negative biconcave 12 lenses, the meniscus facing concavity into the image space.

The fifth component V consists of glued positive 13 and negative 14 menisci facing concavity into the space of the object, in front of which is placed a negative meniscus 15 facing the concavity into the space of the object.

The proposed lens works as follows.

The lens works with a tube lens f '= 200 mm.

Rays from the object of observation, located in the front focal plane of the micro-lens, pass through the first component I - glued the positive lens 2 and the negative meniscus 1, forming an imaginary enlarged image, introducing a positive spherical aberration, chromaticity of position and magnification.

Component II of lens 3, 4, 5, and 6 also constructs an enlarged imaginary image of the object, introducing astigmatism, curvature and a large coma, correcting spherical aberration, chromaticity of position and magnification.

Further, the component III of the lens 9, 7 and 8 forms a real enlarged image, reducing astigmatism and curvature, spherical aberration, chromaticity of position and magnification, compensating for the coma.

Component IV of the lens 10, 11 and 12 builds a real image of the object in the focal plane of component V, correcting astigmatism and curvature.

Component V of the lens 15, 13 and 14 transfers the image of the object to infinity, forming a planochromatic high-contrast image of the object.

According to the proposed scheme, micro lenses with an increase of 63 ^x , a numerical aperture of 1.2 water immersion and 1.25 oil immersion, and a linear image field of 25 mm are realized.

Table 1 presents the Strehl number, which characterizes the image quality of the micro-lens for the relative values of the image values for the lens of water immersion.

Table 1 Rel image value Strehl number one 0.61 0.866 0.75 0.707 0.83 0.5 0.88 0 0.94

INFORMATION SOURCES

1. The lens 63 × 1.2 of water immersion p.11 "Appendix to the dissertation" Theory, design methods and calculation of microscope optics ", 1985

2. RU, utility model No. 36535 U1, G02B 21/02, 2003 - prototype.

Claims (2)

1. Plano-chromatic high-aperture micro lens of large magnification, containing five components in series, the first of which is made in the form of a meniscus convex to the image space, the second, consisting of two positive lenses, the third, glued from two lenses, the fourth, containing a single positive and glued from a positive and negative lens, and a fifth component, comprising a double-bonded lens from a positive and negative lenses, characterized in that the first component made of glued from a negative meniscus convex to the image space and an additional positive lens located in front of the meniscus, the positive lenses of the second component are glued, the first of the positive and negative menisci convex into the image space, and the second of a biconvex positive lens and negative meniscus convex to the image space, the third glued component consists of a negative meniscus facing in the fourth component, the single positive lens is made in the form of a meniscus turned concavity into the image space, and the double-glued lens of the fifth component is made of two menisci turned concavity into the space of the object , and in front of it is additionally placed a single meniscus facing concavity into the space of the object. 2. Plano-chromatic high-aperture micro lens of large magnification according to claim 1, characterized in that the refractive indices of the negative meniscus of the first component, the negative menisci of the second component, the negative lens in the gluing of the fourth component and the negative meniscus of gluing the fifth component have the values 1.78≤n _d ≤1.85, and their dispersion coefficients are 40≤ν _d ≤47, the refractive indices of the negative meniscus in the gluing of the third component and the positive meniscus in the gluing of the fifth component are 1.8≤n _d ≤1.85, and their dispersion coefficients are 22≤ν _d ≤25.

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