IMMERSION MICROSCOPE OBJECTIVE

• US 20190324256A1
• Filed: 04/08/2019
• Published: 10/24/2019
• Est. Priority Date: 04/19/2018
• Status: Active Grant

• Current Assignee: Evident Corporation
• Original Assignee: Olympus Corporation
• Inventors: KUWANO, Makoto, ARASHI, Bunryu
• Granted Patent: US 10,884,229 B2
• Time in Patent Office: Days
• CPC Class Codes: G02B 21/0072 details concerning resolution or correction, including general design of CSOM objectives
• CPC Class Codes: G02B 21/0076 arrangements using fluorescence or luminescence
• CPC Class Codes: G02B 21/02 Objectives
• CPC Class Codes: G02B 21/33 Immersion oils , or microscope systems or objectives for use with immersion fluids

Abstract

An immersion microscope objective includes: a first lens group that includes a meniscus lens component that is the closest to an image in the first lens group, the meniscus lens component having a convex surface facing an object; and a second lens group, the objective satisfying the following conditional expressions:

1.4<NA_ob≤1.51  (1)

1.30 mm≤Y_reso×NA_ob⁸  (2)

L_total≤65 mm  (10)

• • where NA_ob indicates the numerical aperture of the objective; Y_reso a maximum object height within a region on a plane orthogonal to an optical axis that crosses a position on the optical axis at which an RMS wave aberration in a d line is minimized, the region having an RMS wave aberration in the d line that is 0.1λ_d or less provided therewithin; λ_d, the wavelength of the d line; L_total, a distance on the optical axis from an object surface to the lens surface that is the closest to the image.

Claims

1. An immersion microscope objective comprising:

a first lens group that includes a meniscus lens component that is the closest to an image among lens components of the first lens group, the meniscus lens component having a convex surface facing an object; and

a second lens group that is closer to the image than the first lens group is, wherein

the immersion microscope objective satisfies the following conditional expressions;

1.4<

NA_ob≤

1.51 

 

(1)

1.30 mm≤

Y_reso×

NA_ob⁸ 

 

(2)

L_total≤

65 mm 

 

(10)

where NA_ob indicates a numerical aperture of an object side of the immersion microscope objective, Y_reso indicates a maximum object height within a region on a plane orthogonal to an optical axis that crosses a position on the optical axis at which an RMS wave aberration in a d line is minimized, the region having an RMS wave aberration in the d line that is 0.1λ

_d or less provided therewithin, λ

_d indicates a wavelength of the d line, and L_total indicates a distance on the optical axis from an object surface to a lens surface that is closest to the image among lens surfaces of the immersion microscope objective.

2. The immersion microscope objective of claim 1, having a 40-fold magnification or higher.

3. The immersion microscope objective of claim 1, satisfying the following conditional expression:

−

2≤

Δ

z₁/DOF_d≤

2 

 

(3)

where Δ

z₁ indicates a difference between a position on the optical axis at which an RMS wave aberration in an h line is minimized and the position on the optical axis at which an RMS wave aberration in the d line is minimized, and DOF_d indicates a depth of focus for the d line.

4. The immersion microscope objective of claim 2, satisfying the following conditional expression:

−

2≤

Δ

z₁/DOF_d≤

2 

 

(3)

where Δ

z₁ indicates a difference between a position on the optical axis at which an RMS wave aberration in an h line is minimized and the position on the optical axis at which an RMS wave aberration in the d line is minimized, and DOF_d indicates a depth of focus for the d line.

5. The immersion microscope objective of claim 1, wherein

the first lens group includes a first cemented lens that is closest to the object among lenses of the first lens group,

the first cemented lens consists of

a planoconvex lens having a plane surface facing the object, and

a meniscus lens with a negative refractive power that has a concave surface facing the object, and

the object, the planoconvex lens, and the meniscus lens are arranged in this order.

6. The immersion microscope objective of claim 2, wherein

the first lens group includes a first cemented lens that is closest to the object among lenses of the first lens group,

the first cemented lens consists of

a planoconvex lens having a plane surface facing the object, and

a meniscus lens with a negative refractive power that has a concave surface facing the object, and

the object, the planoconvex lens, and the meniscus lens are arranged in this order.

7. The immersion microscope objective of claim 3, wherein

the first lens group includes a first cemented lens that is closest to the object among lenses of the first lens group,

the first cemented lens consists of

a planoconvex lens having a plane surface facing the object, and

a meniscus lens with a negative refractive power that has a concave surface facing the object, and

the object, the planoconvex lens, and the meniscus lens are arranged in this order.

8. The immersion microscope objective of claim 4, wherein

the first lens group includes a first cemented lens that is closest to the object among lenses of the first lens group,

the first cemented lens consists of

a planoconvex lens having a plane surface facing the object, and

a meniscus lens with a negative refractive power that has a concave surface facing the object, and

the object, the planoconvex lens, and the meniscus lens are arranged in this order.

9. The immersion microscope objective of claim 5, wherein

the first lens group further includes a biconvex lens,

the biconvex lens is included in a lens component that is closest, second closest, or third closest to the object among lens components of the immersion microscope objective, and

the immersion microscope objective satisfies the following conditional expression:

1.4≤

n13≤

1.85 

 

(4)

where n13 indicates a refractive index that the biconvex lens has for the d line.

10. The immersion microscope objective of claim 6, wherein

the first lens group further includes a biconvex lens,

the biconvex lens is included in a lens component that is closest, second closest, or third closest to the object among lens components of the immersion microscope objective, and

the immersion microscope objective satisfies the following conditional expression:

1.4≤

n13≤

1.85 

 

(4)

where n13 indicates a refractive index that the biconvex lens has for the d line.

11. The immersion microscope objective of claim 7, wherein

the first lens group further includes a biconvex lens,

the biconvex lens is included in a lens component that is closest, second closest, or third closest to the object among lens components of the immersion microscope objective, and

the immersion microscope objective satisfies the following conditional expression:

1.4≤

n13≤

1.85 

 

(4)

where n13 indicates a refractive index that the biconvex lens has for the d line.

12. The immersion microscope objective of claim 8, wherein

the first lens group further includes a biconvex lens,

the biconvex lens is included in a lens component that is closest, second closest, or third closest to the object among lens components of the immersion microscope objective, and

the immersion microscope objective satisfies the following conditional expression:

1.4≤

n13≤

1.85 

 

(4)

where n13 indicates a refractive index that the biconvex lens has for the d line.

13. The immersion microscope objective of claim 9, satisfying the following conditional expression:

0≤

|R1|/|R2|≤

1 

 

(5)

where R1 indicates a radius of curvature of a lens surface on an object side of the biconvex lens, and R2 indicates a radius of curvature of a lens surface on an image side of the biconvex lens.

14. The immersion microscope objective of claim 10, satisfying the following conditional expression:

0≤

|R1|/|R2|≤

1 

 

(5)

where R1 indicates a radius of curvature of a lens surface on an object side of the biconvex lens, and R2 indicates a radius of curvature of a lens surface on an image side of the biconvex lens.

15. The immersion microscope objective of claim 11, satisfying the following conditional expression:

0≤

|R1|/|R2|≤

1 

 

(5)

where R1 indicates a radius of curvature of a lens surface on an object side of the biconvex lens, and R2 indicates a radius of curvature of a lens surface on an image side of the biconvex lens.

16. The immersion microscope objective of claim 9, wherein

the second lens group includes

a lens component that is closest to the object among lens components of the second lens group, the lens component having a concave surface facing the object, and

at least one lens component.

17. The immersion microscope objective of claim 9, satisfying the following conditional expressions:

2.4≤

f1/fob 

 

(6)

1.8≤

n12≤

1.85 

 

(7)

where f1 indicates a focal length that the first cemented lens has for the d line, fob indicates a focal length that the immersion microscope objective has for the d line, and n12 indicates a refractive index that the meniscus lens has for the d line.

18. The immersion microscope objective of claim 9, satisfying the following conditional expression:

0.095≤

d12/L_total 

 

(8)

where d12 indicates a thickness that the meniscus lens has on the optical axis, and L_total indicates the distance on the optical axis from the object surface to the lens surface that is the closest to the image among the lens surfaces of the immersion microscope objective.

19. The immersion microscope objective of claim 9, satisfying the following conditional expression:

2≤

h1/h2≤

3 

 

(9)

where h1 indicates a height of an axial marginal ray at a lens surface on an object side of the meniscus lens component, and h2 indicates a height of the axial marginal ray at a lens surface on an image side of the meniscus lens component.