RU2239213C2 - Ocular - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: device has two components, first of which along beams path is two-lens, glued together of negative meniscus directed by convex portion to object and first biconvex lens, second component - second biconvex lens. Between radiuses of optical surfaces, refraction coefficients and focus distance of ocular certain relations are true, which are presented in invention formula.

EFFECT: higher adaptability to manufacture with high image quality.

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Description

The present invention relates to optical instrumentation and can be used in various telescopic systems and microscopes.

A known optical system of a three-lens eyepiece [1], consisting of (in order from the observer’s eye) the first component - a biconvex lens and the second component - glued, consisting of a biconvex lens and a negative lens, and the following condition is satisfied:

-5.3 <{Rc / (n’-n)} / f ’<- 3.8,

where Rc is the radius of curvature of the glued surface;

n and n ’are the refractive index of the lens elements located respectively before and after the glued surface;

f ’is the focal length of the entire eyepiece.

But this eyepiece has low adaptability, since all the radii of the optical surfaces are different, which requires the use of its own test glass and a processing tool on each optical surface.

The closest analogue to the claimed technical solution is the eyepiece [2], which consists of (in order from the object) two components, the first of which is a two-lens glued from the negative meniscus convex to the object and the first biconvex lens, the second component the second biconvex lens with a more strongly convex surface on the side of the subject. Moreover, the specified eyepiece satisfies the following condition:

1.40f ’<D <1.48f’,

where D is the distance from the anterior focal point of the eyepiece to the top of the second surface along the rays of the second biconvex lens;

f ’is the focal length of the entire eyepiece.

This eyepiece has low adaptability, since all the radii of the optical surfaces are different, which requires the use of its own test glass and a processing tool on each optical surface.

The task of the invention is the creation of an eyepiece with higher adaptability with high image quality.

The technical result is an increase in the manufacturability of the eyepiece with high image quality.

This is achieved by the fact that in an eyepiece containing two components, the first of which along the rays is a two-lens glued from a negative meniscus convex to the object and a biconvex lens, the second component is a single biconvex lens, in which, unlike the known one, the relation :

| R ₃ | = R ₄ = | R ₅ |,

1,1f ’<D <1,4f’,

1.64 <n ₁ <1.78,

n ₂ = n ₃ ,

1.59 <n ₂ = n ₃ <1.62,

where R ₃ is the radius of the third optical surface;

R ₄ is the radius of the fourth optical surface;

R ₅ is the radius of the fifth optical surface;

D is the distance from the anterior focal point of the eyepiece to the top of the second surface along the rays of the second biconvex lens;

f ’is the focal length of the entire eyepiece;

n ₁ is the refractive index of the material of the first lens along the beam;

n ₂ is the refractive index of the material of the second lens along the beam;

n ₃ is the refractive index of the material of the third lens along the beam.

The drawing shows an optical diagram of the eyepiece. The eyepiece consists of two components sequentially located along the beam from the object, the first of which is a two-lens glued from the negative meniscus 1, convex to the object, and a biconvex lens 2, the second is a single biconvex lens 3. The exit pupil is located behind lens 3.

The eyepiece works as follows:

In front of part 1 is the plane of objects, which is depicted by the eyepiece at infinity and is viewed by the eye of the observer located behind the lens 3.

As a specific example of the invention, an eyepiece with the following structural data is calculated:

The calculated eyepiece has the following characteristics:

The eyepiece focal length f 'is 24.8 mm.

The diameter of the exit pupil is 5.6 mm.

The angular field in the image space is 46 degrees.

20 mm exit pupil removal.

The eyepiece has aberrations for λ = 0.54607 μm:

- longitudinal spherical aberration of 0.164 mm

- meridional image curvature 0.843 mm

- sagittal image curvature 0.764 mm

- distortion with an angular field of 46 degrees. 8.8%

Thus, as a result of the proposed solution, a technical result is obtained: a more technological eyepiece with a high image quality, with an angular field in the image space of up to 46 degrees is created. when removing the exit pupil of 20 mm.

Sources of information

1. US patent No. 5731905, G 02 In 25/00; NCI 359/646; 359/744, publ. 1998 year

2. US Patent No. 5764418, G 02 B 25/00, G 02 B 13/18; NCI 359/646; 359/717, publ. 1998 year

Claims (1)

An eyepiece containing two components, the first of which along the rays is a two-lens one, glued from the negative meniscus convex to the object and the first biconvex lens, the second component is the second biconvex lens, characterized in that there are relations | R ₃ | = R ₄ = | R ₅ |; 1,1f ’<D <1,4f’; 1.64 <n ₁ <1.78; n ₂ = n ₃ ; 1.59 <n ₂ = n ₃ <1.62, where R ₃ is the radius of the third optical surface; R ₄ is the radius of the fourth optical surface; R ₅ is the radius of the fifth optical surface; D is the distance from the anterior focal point of the eyepiece to the top of the second surface along the rays of the second biconvex lens; f ’is the focal length of the entire eyepiece; n ₁ is the refractive index of the material of the first lens along the beam; n ₂ is the refractive index of the material of the second lens along the beam; n ₃ is the refractive index of the material of the third lens along the beam.