CN2400808Y

CN2400808Y - Large field achromatic microscope objective

Info

Publication number: CN2400808Y
Application number: CN 99252126
Authority: CN
Inventors: 徐文东; 林强
Original assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Current assignee: Shanghai Institute of Optics and Fine Mechanics of CAS
Priority date: 1999-12-16
Filing date: 1999-12-16
Publication date: 2000-10-11
Anticipated expiration: 2009-12-16

Abstract

An object lens barrel with an incident light hole at the front end and an exit light hole at the rear end comprises an object lens barrel, wherein a meniscus thick lens, a biconvex single positive lens, a diaphragm, a first double cemented lens, a second double cemented lens containing a rear thick biconvex lens and a meniscus positive lens which have a larger distance with the first double cemented lens are sequentially arranged in the object lens barrel from the incident light hole to the exit light hole along the same central axis. The utility model discloses have big visual field, image space visual field diameter reaches 25 mm. Field curvature, spherical aberration, coma, axial chromatic aberration, and other aberrations are better corrected.

Description

Big visual field flat field achromatism micro objective

The utility model relates to a kind of big visual field flat field achromatism micro objective, and it is the 40 * flat field achromatism biology microscope endoscope objective lens of a kind of picture side field number greater than 25mm specifically.

In the prior art, flat field achromatism micro objective usually requires the calibration curvature of field well on than the basis of positive spherical aberration, coma, axial chromatic aberration and astigmatism." a kind of micro objective that provides in the optical technology handbook (referring to " the optical technology handbook, China Machine Press, in November, 1987, the first volume, p987, β=40 *) mainly exist the visual field little, the shortcoming that aberration is big.

The purpose of this utility model is in order to remedy the shortcoming of the micro objective in the above-mentioned prior art, to provide a kind of picture side field number greater than 25mm, and numerical aperture is 0.65, the 40 * big visual field flat field achromatism micro objectives that various aberration corrections are good.

The utility model micro objective comprises: front end has entrance pupil 2 rear ends that the objective tube 9 of exit pupil 10 is arranged, in

objective tube

9,10 be equipped with successively: thick meniscus lens 3 from entrance pupil 2 to exit pupil, single-positive-lens 4, diaphragm 5, first cemented doublet, 6, the second cemented doublets 7 and falcate positive lens 8; Outside objective tube 9, be equipped with Cover Glass 1 (see figure 1) before the entrance pupil 2.

The central axis OO of the central axis of above-mentioned each lens and objective tube 9 coincides.That is to say that the optical axis of each lens is all on central axis OO.The concrete structure of each lens and position each other are as follows:

The concave surface of said thick meniscus lens 3 is towards entrance pupil 2.As refractive index N _D1=1.6204, chromatic dispersion ν _D1=60.29 o'clock, its concave curvature radius R ₁=1.4249～1.4353, the convex curvature radius R ₂=2.0852～2.0901, center thickness T ₁=2.4629～2.4714.

Said single-positive-lens 4 is biconvex lens.One side towards entrance pupil 2 is called convex front surface, and the one side of carrying entrance pupil 2 is called the back convex surface.As refractive index N _D2=1.48746, chromatic dispersion ν _D2=70.04 o'clock, the convex front surface radius of curvature R ₃=-16.6474～-16.5923, back convex curvature radius R ₄=4.8491～4.8555, center thickness T ₂=2.3964～2.4125.

Said first cemented doublet 6 is glued together by a concave-convex lens and a biconvex lens and constitutes.Wherein concave-convex lens is called the front in the direction towards entrance pupil 2, and biconvex lens in the back.The convex front surface of the concave surface of the concave-convex lens of front and the biconvex lens of the back centre cemented surface that is called glued together.The front concave-convex lens is as refractive index N _D3=1.80627, chromatic dispersion ν _D3=25.37 o'clock, the convex curvature radius R ₅=185.1434～202.5144, center thickness T ₃=0.7986～0.8690; The back biconvex lens is as refractive index N _D4=1.48746, chromatic dispersion ν _D4=70.04 o'clock, back convex curvature radius R ₇=15.0100～15.0813, center thickness T ₄=2.0432～2.0532; The cemented surface radius of curvature R of two lens ₆=-4.9548～-4.9514.

Said second cemented doublet 7 is to be formed by the thick biconvex lens gummed of preceding thin concave-convex lens and back.The radius of curvature R of the cemented surface in the middle of both ₉=-61.1547～-59.3472.Preceding thin concave-convex lens is as refractive index N _D5=1.72340, chromatic dispersion ν _D5=37.99 o'clock, the convex curvature radius R ₈=-36.5562～-36.3867, center thickness T ₅=1.0801～1.1074; The thick biconvex lens in back is as refractive index N _D6=1.51478, chromatic dispersion ν _D6=60.63 o'clock, back convex curvature radius R ₁₀=11.1879～11.1977, center thickness T ₆=5.7164～5.7466.

The concave surface of said falcate positive lens 8 is towards exit pupil 10.As refractive index N _D7=1.72000, chromatic dispersion ν _D7=50.41 o'clock, its convex curvature radius R ₁₁=-8.4988～-8.4815, the concave curvature radius R ₁₂=-5.7149～-5.7046, center thickness T ₇=2.5601～2.5851.

Above said before with towards the direction of entrance pupil 2 be being divided into of back before, carry entrance pupil 2 and towards exit pupil 10 directions be after.

The distance of above-mentioned each lens on central axis OO is respectively: thick meniscus lens 3 and place entrance pupil outside the objective tube 92 before Cover Glass 1 between apart from S ₁=0.3950～0.4050, between single-positive-lens 4 and the thick meniscus lens 3 apart from S ₂=0.3977～0.4226, between single-positive-lens 4 and the diaphragm 5 apart from S ₃Between=-0.01153～0.008, first cemented doublet 6 and the diaphragm 5 apart from S ₄Between=0.3950～0.4050, second cemented doublet 7 and first cemented doublet 6 apart from S ₅=5.6773～5.7376, between the falcate positive lens 8 and second cemented doublet 7 apart from S ₆=5.5976～5.6308.Shown in Fig. 1 and table 1.

The radius of curvature R of above-mentioned each lens, center thickness T and the long measure apart from S between the two are millimeter (mm).When radius of curvature R was negative value, the centre of sphere of representing this sphere was in the picture side of this sphere one side.

The micro objective of said structure, its refractive index N _dWith chromatic dispersion ν _dFootmark d, be that expression is when the wavelength X of incident light _dDuring=0.58756 μ m, the refractive index N of each

lens

3,4,6,7,8 _dWith chromatic dispersion ν _dAs shown in table 1.

Table 1 is the radius of curvature R of each lens, and center thickness T is between the two apart from S and refractive index N _d, chromatic dispersion ν _dThe detailed data table:

The utility model has the advantages that: above-mentioned micro objective has big visual field and proofreaies and correct good aberration.Compare with the micro objective in the prior art, the single-positive-lens 4 of the utility model micro objective is a biconvex lens, the center thickness T of the back thick biconvex lens in second cemented doublet 7 ₆Increased, and between second cemented doublet 7 and first cemented doublet 6 apart from S ₅Strengthened etc., this all helps the correction of the curvature of field, aberration.So the utility model micro objective curvature of field has obtained better correction, the visual field is bigger, has also proofreaied and correct spherical aberration, coma better, axial chromatic aberration and other aberration.Compare with the micro objective in the prior art, reach 25mm as square field number, as can be seen from Figure 2, when the spatial modulation frequency is every millimeter 600 cycle, be that the degree of modulation of the meridian of 25mm (radius 12.5mm) and sagitta of arc optical modulation function is all greater than 0.4 as square field number.The maximum optical path difference of meridian direction (Y direction) is less than 1.2 wavelength when full visual field (object height 12.5mm), and sagitta of arc direction (directions X) maximum optical path difference is less than 0.5 wavelength (see figure 3).

Description of drawings:

Fig. 1 is the structural representation of the micro objective that provides in the utility model

Fig. 2 is the degree of modulation curve of the optical transfer function of the utility model micro objective

Fig. 3 is the wave aberration curve of the utility model micro objective when different object height

Embodiment: the structure of present embodiment micro objective as shown in Figure 1.When focal length equaled 4.359mm, each parameter of present embodiment micro objective saw Table 2.

Table 2 is the radius of curvature R of each lens among the embodiment, center thickness T, each other apart from S, refractive index N _dWith chromatic dispersion ν _dTables of data:

Best 0 visual field of realizing, 0.707 visual field (as square visual field radius 8.84mm), the degree of modulation curve of the optical transfer function of full visual field (as square visual field radius 12.5mm) the spatial modulation frequency during less than every millimeter 600 cycle all greater than 0.4 (see figure 2).At object height is 0.00mm (i.e. 0 visual field), 8.84mm the maximum optical path difference of meridian direction (directions X) and sagitta of arc direction (Y direction) is all less than 0.5 wavelength when (i.e. 0.707 visual field), the maximum optical path difference of meridian direction (Y direction) is less than 1.2 wavelength when object height 12.5mm (full visual field), and sagitta of arc direction (directions X) maximum optical path difference is less than 0.5 wavelength (see figure 3).So present embodiment has fully proved above-mentioned advantage of the present utility model.

Claims

1. one kind big visual field flat field achromatism micro objective comprises:

＜1〉front end has entrance pupil (2) rear end that the objective tube (9) of exit pupil (10) is arranged, in objective tube (9), upward be equipped with thick meniscus lens (3) successively to exit pupil (10) from entrance pupil (2) along same central axis (OO), single-positive-lens (4), diaphragm (5), first cemented doublet (6), second cemented doublet (7) and falcate positive lens (8), the preceding Cover Glass (1) that is equipped with of entrance pupil (2) outside lens barrel (9);

It is characterized in that:

＜2〉concave surface of thick meniscus lens (3) is towards entrance pupil (2), as refractive index N _D1=1.6204, chromatic dispersion ν _D1=60.29 o'clock, its concave curvature radius R ₁Be 1.4249 to 1.4353, the convex curvature radius R ₂Be 2.0852 to 2.0901, center thickness T ₁Be 2.4629 to 2.4714;

＜3〉single-positive-lens (4) is a biconvex lens, as refractive index N _D2=1.48746, chromatic dispersion ν _D2=70.04 o'clock, the convex front surface radius of curvature R ₃Be-16.6474 to-16.5923, back convex curvature radius R ₄Be 4.8491 to 4.8555, center thickness T ₂Be 2.3964 to 2.4125;

＜4〉first cemented doublet (6) is that convex front surface by the concave surface of front one concave-convex lens and back one biconvex lens composes cemented surface and constitutes, and the front concave-convex lens is as refractive index N _D3=1.80627, chromatic dispersion ν _D3=25.37 o'clock, its convex curvature radius R ₅Be 185.1434 to 202.5144, center thickness T ₃Be 0.7986 to 0.8690; The back biconvex lens is as refractive index N _D4=1.48767, chromatic dispersion ν _D4=70.04 o'clock, its back convex curvature radius R ₇Be 15.0100 to 15.0813, center thickness T ₄It is the cemented surface radius of curvature R of 2.0432 to 2.0532, two lens ₆Be-4.9548 to-4.9514;

＜5〉second cemented doublet (7) is to form the radius of curvature R of the cemented surface in the middle of both by the thick biconvex lens gummed of preceding thin concave-convex lens and back ₉Be-61.1547 to-59.3472, preceding thin concave-convex lens is as refractive index N _D5=1.72340, chromatic dispersion ν _D5=37.99 o'clock, the convex curvature radius R ₈Be-36.5562 to-36.3867, center thickness T ₅Be 1.0801 to 1.1074; The thick biconvex lens in back is as refractive index N _D6=1.51478, chromatic dispersion ν _D6=60.63 o'clock, back convex curvature radius R ₁₀Be 11.1879 to 11.1977, center thickness T ₆Be 5.7164 to 5.7466;

＜6〉concave surface of falcate positive lens (8) is towards exit pupil (10), as refractive index N _D7=1.72000, chromatic dispersion ν _D7=50.41 o'clock, its convex curvature radius R ₁₁Be-8.4988 to-8.4815, the concave curvature radius R ₁₂Be-5.7149 to-5.7046, center thickness T ₇Be 2.5601 to 2.5851;

＜7〉distance of above-mentioned each lens on central axis (OO) is respectively: thick meniscus lens (3) and place between the preceding Cover Glass (1) of entrance pupil (2) outside the objective tube (9) apart from S ₁Be 0.3950 to 0.4050, between single-positive-lens (4) and the thick meniscus lens (3) apart from S ₂Be 0.3977 to 0.4226, between single-positive-lens (4) and the diaphragm (5) apart from S ₃For between-0.0115 to 0.0083, the first cemented doublet (6) and the diaphragm (5) apart from S ₄Be between 0.3950 to 0.4050, the second cemented doublet (7) and first cemented doublet (6) apart from S ₅Be 5.6773 to 5.7376, between falcate positive lens (8) and second cemented doublet (7) apart from S ₆Be 5.5976 to 5.6308;

The radius of curvature R of above-mentioned each lens, center thickness T and the long measure apart from S between the two are millimeter.