RU2178903C2 - Fast planapochromatic microscope objective - Google Patents

Abstract

FIELD: microscope objectives. SUBSTANCE: the microscope objective has the first single positive component, the second positive component, the third triple-cemented component containing a biconcave lens enclosed between two biconvex lenses, the fourth component cemented of a positive and negative lenses, and the fifth negative component in the form of a meniscus cemented of a positive and negative lenses. The second component is made in the form of a single meniscus facing the object space with the concavity. EFFECT: enhanced lens speed and approved correction of polychromatic aberrations due to correction of spherochromatic aberration. 1 dwg, 1 tbl

Description

 The invention relates to the field of microscopy - to planochromatic lenses of a microscope and can be used to complete laboratory and research models of biological, polarizing, luminescent and other microscopes.

 Planochromats are designed for observing and photographing particularly fine microscopic structures that require high resolution and high image contrast.

 A well-known micro-lens / 1 / containing five components, in which the first component is a positive meniscus facing concavity to the space of objects, the second is a positive component glued from negative and positive lenses, the third is a three-glued component consisting of two negative lenses, between which a positive lens, the fourth is a negative double-glued lens, consisting of a biconvex and biconcave lenses, and the fifth component is a positive double-glued meniscus, consisting of a biconcave and biconvex lenses.

 However, in such a micro lens, it is impossible to increase the aperture ratio and achieve a planochromatic correction, because its design does not allow to efficiently correct polychromatic aberrations (in particular, HRD), as well as the image curvature (residual curvature is 4-5λ).

 Also known is a micro lens / 2 / containing a five-component system in which the first and second components are single menisci, the third is a three-glued component consisting of two negative lenses, between which a positive lens is enclosed, the fourth is a biconvex lens and the fifth component is glued of two negative lenses.

 The specified micro lens does not eliminate the polychromatic aberration of off-axis bundles, which leads to the impossibility of increasing the aperture ratio.

 A well-known micro-lens / 3 / containing five components, in which the first and fifth components are menisci, the first of them facing concavity to the space of objects, and the fifth to the space of images, the second component is a positive lens, glued from negative and positive lenses, and the third and fourth components are triple-bonded lenses consisting of two positive lenses with a negative lens enclosed between them.

 In such a micro lens, it is impossible to correct the polychromatic aberrations of off-axis bundles, there are colored coma, astigmatism, residual CRI is 2%, i.e. in this lens it is impossible to achieve planochromatic correction and increase aperture ratio.

 The closest in technical essence to the proposed solution is a planochromatic microscope objective of a large magnification / 4 / containing a five-component system in which the front positive single meniscus faces the concavity of the space of objects, the second - the positive component is glued from the negative and positive lenses, the third - the three-glued component a biconcave lens enclosed between two biconvex lenses, the fourth component is glued from the positive and negative lenses and The Fifth - negative component in the form of a meniscus, paste of the positive and negative lenses.

 Such a lens has a low output aperture, as a result of which it is impossible to increase the aperture ratio. In addition, it is impossible to achieve planochromatic correction over the entire working field of view due to significant spherochromatic aberrations.

 The objective of the invention is to increase the luminosity while improving the correction of polychromatic aberrations due to the correction of spherochromatic aberration, the solution of which corresponds to the proposed fast plan planochromatic micro-lens, which contains the first single positive component sequentially located along the optical axis, the second positive component, the third component contains a biconcave lens, enclosed between two biconvex lenses, fourth compo ent glued from the positive and negative lens and a negative fifth component in the form of a meniscus, paste of the positive and negative lenses, however, unlike the prototype of the second component is in the form of a single meniscus facing concavity to the object space.

 The essence of the invention lies in the fact that, using the lens made in this way as the second component, we do not use glued surfaces on which (in the frontal part) it is difficult to correct spherochromatic aberrations with increasing aperture.

 The essence of the proposed solution is illustrated by the drawing, which shows a schematic diagram of the lens, as well as table. 1, which presents the design parameters, and table. 2-6 image quality characteristics of one example of a specific implementation.

 The inventive micro lens contains five components located along the optical axis. The first component 1 is a positive single lens, the second component 2 is a single meniscus facing concavity to the space of objects, the third component is a three-glued lens 3, consisting of two biconvex lenses 4 and 6 and a negative lens 5 enclosed between them, the fourth component 7 is glued from a biconvex lens 8 and a negative lens 9, and the fifth component 10 is a negative meniscus glued from a biconvex lens 11 and a negative lens 12.

As an example of a specific design, the calculation of the lens 40 * 0.75 was made, the calculation was made for a standardized tube length, infinity F ' _TL = 160 mm.

 The proposed lens works as follows.

Frontal single menisci of 1 and 2 of finite thickness build an enlarged imaginary image of the lens with a corrected image curvature and moderate values of residual aberrations. The three-lens bonded component 3, operating with an increase in V ₃ = 1-5 ^x , compensates for the chromatic difference in positions introduced by components 1, 2, 10 at moderate values of spherical aberration. Component 7 projects the image of the object into the object plane of the meniscus 10, compensating for the secondary spectrum introduced by the three-glued lens 3. Meniscus 10 constructs the image of the object at infinity. In this case, meniscus aberrations 10 (image curvature, astigmatism, secondary spectrum) are opposite in sign to the aberrations of the positive elements of the lens.

 From the materials presented in the “Appendix”, it follows that the implementation of the second component in this way allowed us to achieve optimal correction of spherochromatic aberrations, which allowed us to increase the input aperture and aperture of the micro lens by 1.3 times, achieving a plan-chromatic correction over the entire field of view.

Sources of information
1. US patent 4,540.248, M. cl. G 02 B 9/62, 1985

 2. Japan patent 54-10.496, M. cl. G 02 B, 1979

 3. Copyright certificate of the USSR 200807, M. cl. G 02 B, 1966

 4. Copyright certificate of the USSR 1.485.184 (prototype), M. cl. G 02 B 21/02, 1989

Claims (1)

 A fast plan-chromatic micro-lens that contains the first single positive component sequentially located along the optical axis, the second positive component, the third three-glued component contains a biconcave lens enclosed between two biconvex lenses, the fourth component is glued from the positive and negative lenses, and the fifth negative component in the form of a meniscus, glued from positive and negative lenses, characterized in that the second component is made in the form of a single m Niska facing concavity to space objects.

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