US 2003/0197945 A1 · Objective lens

Abstract

An objective lens includes a first lens group, a second lens group having a lens pair, a third lens group having a lens pair, a fourth lens group having a lens pair, a fifth lens group having a lens pair, and a sixth lens group. The objective lens is configured so as to satisfy the following conditional expressions: d/L<0.025 0.58<Rp/Rn<1.65 where L(mm) is the overall length of the objective lens; d(mm) is the air gap of each of the lens pair; Rp is the radius of curvature of each of positive refractive power surfaces opposing each other with the air gap therebetween; and Rn is the radius of curvature of a negative refractive power surface. Whereby, chromatic aberration can be corrected and resolution is exponentially improved without using a cemented lens, providing a deep ultra-violet objective lens with a high NA capable of auto focussing instantaneously.

Drawings

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Drawings

Claims15

Dependent claims

An objective lens having an NA of at least 0.7 and being constituted by combining a plurality of single lenses as a whole, the objective lens comprising:

a first lens group having a positive meniscus lens with a convex surface facing an image side and a negative biconcave lens, which are arranged in the sequential order from the image side, so as to have negative refractive power as a whole;
a second lens group having at least one couple of a lens pair so as to have positive refractive power as a whole, said lens pair having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a third lens group having four couples of lens pairs so as to have positive refractive power as a whole, each couple of said lens pairs having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a fourth lens group having two couples of lens pairs, each couple of said lens pairs having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a fifth lens group having one couple of a lens pair so as to have positive refractive power as a whole, said lens pair having a positive lens and a negative lens including a negative meniscus lens with a concave surface facing an object side, which are made of media different from each other and are arranged to have an air gap therebetween;
and
a sixth lens group having at least one positive lens and a positive meniscus lens with a concave surface facing the object side so as to have positive refractive power as a whole,
wherein the objective lens satisfies the following conditional expressions:
d/L<0.025 0.58<Rp/Rn<1.65,
where L(mm) is the overall length of the objective lens;
d(mm) is the air gap of the lens pair;
Rp is the radius of curvature of each of positive refractive power surfaces opposing each other with the air gap therebetween;
and Rn is the radius of curvature of a negative refractive power surface.

10 more elements

An objective lens having an NA of at least 0.7 and being constituted by combining a plurality of single lenses as a whole, the objective lens comprising:

a first lens group having a positive meniscus lens with a convex surface facing an image side and a negative biconcave lens, which are arranged in the sequential order from the image side, so as to have negative refractive power as a whole;
a second lens group having at least one couple of a lens pair so as to have positive refractive power as a whole, said lens pair having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a third lens group having two units, each unit comprising three lenses including a positive lens and a negative lens which are made of media different from each other and are arranged to have an air gap therebetween, so as to have positive refractive power as a whole;
a fourth lens group having two couples of lens pairs, each couple of said lens pairs having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a fifth lens group having one couple of a lens pair so as to have positive refractive power as a whole, said lens pair having a positive lens and a negative lens including a negative meniscus lens with a concave surface facing an object side, which are made of media different from each other and are arranged to have an air gap therebetween;
and
a sixth lens group having at least one positive lens and a positive meniscus lens with a concave surface facing the object side so as to have positive refractive power as a whole,
wherein the objective lens satisfies the following conditional expressions:
d/L<0.025 0.58<Rp/Rn<1.65,
where L(mm) is the overall length of the objective lens;
d(mm) is the air gap of the lens pair;
Rp is the radius of curvature of each of positive refractive power surfaces opposing each other with the air gap therebetween;
and Rn is the radius of curvature of a negative refractive power surface.

10 more elements

An optical apparatus comprising:

an objective lens;
a first illumination unit comprising a light source generating ultra-violet light and an illumination optical system leading the ultra-violet light to the objective lens;
and
a second illumination unit comprising a light source generating infrared light and an illumination optical system leading the infrared light to the objective lens,
wherein a specimen is illuminated with the ultra-violet light and the infrared light through the objective lens,
wherein in the objective lens having an NA of at least 0.7 and being constituted by combining a plurality of single lenses as a whole, the objective lens comprises:
a first lens group having a positive meniscus lens with a convex surface facing an image side and a negative biconcave lens, which are arranged in the sequential order from the image side, so as to have negative refractive power as a whole;
a second lens group having at least one couple of a lens pair so as to have positive refractive power as a whole, said lens pair having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a third lens group having four couples of lens pairs so as to have positive refractive power as a whole, each couple of said lens pairs having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a fourth lens group having two couples of lens pairs, each couple of said lens paris having a positive lens and a negative lens, which are made of media different from each other and are arranged to have an air gap therebetween;
a fifth lens group having one couple of a lens pair so as to have positive refractive power as a whole, said lens pair having a positive lens and a negative lens including a negative meniscus lens with a concave surface facing an object side, which are made of media different from each other and are arranged to have an air gap therebetween;
and
a sixth lens group having at least one positive lens and a positive meniscus lens with a concave surface facing the object side so as to have positive refractive power as a whole, and
wherein the objective lens satisfies the following conditional expressions:
d/L<0.025 0.58<Rp/Rn<1.65,
where L(mm) is the overall length of the objective lens;
d(mm) is the air gap of the lens pair;
Rp is the radius of curvature of each of positive refractive power surfaces opposing each other with the air gap therebetween;
and Rn is the radius of curvature of a negative refractive power surface.

16 more elements

Dependencies are inferred from the claim text.

Description10,446 words

Summary4,866 words

#1. Field of the Invention

#The present invention relates to objective lenses, and in particular relates to an objective lens used in a deep ultraviolet-wavelength region around a wavelength of 250 nm for a high-NA (numerical aperture), high-power, and infinity-correction type microscope.

#2. Description of the Related Art

Brief description of the drawings14 figures

#FIG. 1 is a schematic structural drawing showing an optical path relating to AF of a general microscope.

#FIG. 2 is a schematic structural drawing of an objective lens according to a first embodiment of the present invention.

#FIG. 3(a), FIG. 3(b), and FIG. 3(c) are drawings showing spherical aberration, curvature of field, and distortion of the objective lens according to the first embodiment, respectively.

Detailed description5,257 words

#Embodiments according to the present invention will be described below with reference to FIGS. 2 to 14. According to all the embodiments of the present invention, the focal length of an objective lens is 1.8 mm and a correction wavelength band in a deep ultra-violet region is 248±5 nm, and when combined with an image-formation lens having a focal length of 180 mm, the objective lens has a field number of φ5.5 mm and the magnification becomes 100 times as. The chromatic aberration is corrected in a range of 248±5 nm so as to enable the lens to be used in combination with a KrF excimer laser not reduced in a wavelength band. Also, because an adhesive is not used therein, the lens has a sufficient resistance against a laser with high energy. Furthermore, combining the lens with a band pass filter having a full width at half maximum of about 7 nm also enables a specimen to be observed by illuminating it with a mercury lamp as a preliminary stage of laser irradiation. Also, suppressing the displacement in the image formation in a deep ultra-violet region and infrared region enables the AF to be performed.

#In each embodiment, aberration shown in an aberration chart indicates aberration on an object plane when the simple objective lens is inversely followed, and their units are mm and %. As for spherical aberration, a dotted line indicates the aberration employing a wavelength of 248 nm; a dotted chain line indicates that of 243 nm; and a solid line indicates that of 253 nm.

#First Embodiment

Facts

Application

10/295,821Filed 18 Nov 2002

Priority

JP 2001-2081259 Jul 2001

Published

23 Oct 2003

Term ends

Not estimatedThe source records don’t support an estimate.

Classification4 codes

G02B 13/143
For use with infrared or ultraviolet radiation: for use with ultraviolet radiation
G02B 21/02
Microscopes: objectives
G02B 21/16
Microscopes: adapted for ultraviolet illumination ; Fluorescence microscopes
G02B
Optical elements, systems or apparatus

Timeline

9 Jul 2001Priority claimedJP 2001-208125
18 Nov 2002Application filedUS 10/295,821
18 Nov 2002Assigned to Olympus Optical Co., Ltd.assignment of assignor's interest
23 Oct 2003PublishedUS 2003/0133198 A1
11 May 2004Assigned to Olympus Corporationassignment of assignor's interest
11 May 2004Assigned to Olympus Corporationchange of name
18 May 2005Assigned to Olympus Corporationre-record to correct assignee address previously recorded at reel/frame 015397/0950
27 Jun 2016Assigned to Olympus Corporationchange of address
27 Jun 2022Assigned to Evident Corporationassignment of assignor's interest

Objective lens

Life of this patent

Objective lens

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims15

Description10,446 words

Drawings

Classification4 codes

Life of this patent

Description10,446 words