RU2364901C1 - Ocular - Google Patents

Abstract

FIELD: physics, optics.

SUBSTANCE: ocular comprises two components, the first of which along with direction of rays is two-lens and glued of concavo-concave and convexo-convex lenses, the second component is a convexo-convex lens. In ocular between structural parametres the following ratios are obtained: 1.64 < n₁ < 1.78; 1.59 < n₂ = n₃ < 1.62; |R₄| < |R₅|, |R₂| = |R₃| = |R₄|, where: n₁, n₂, n₃ are indices of refraction of material in the first, second and third lenses for line e; R₂, R₃, R₄, R₅ are radiuses of the second, third, fourth ad fifth optic surfaces.

EFFECT: increased angular field in images space and removal of exit pupil with high quality of image and level of manufacturability.

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Description

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

Known three-lens eyepiece (US patent No. 5764418; G02B 25/00; 13/18; NCI 359/646; 359/717, publ. 1998), consisting of (in order from the subject) of two components, the first of which two-lens, glued from a biconcave lens and the first biconvex lens, the second component is the second biconvex lens with a steeper optical surface on the side of the subject. The condition is met:

1.40f <D <l, 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.

The eyepiece has low adaptability, since the radii of at least four 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 an eyepiece (Russian patent No. 2239213; G02В 25/00, publ. 2004), containing two components, the first of which, along the rays, is a two-lens one glued from a negative meniscus convex to the object, and the first biconvex lens, the second component is the second biconvex lens and, in addition, there are relations:

| R ₃ | = R ₄ = | R ₅ |,

1,1f ′ <D <1,4f ′,

1.64 <n ₁ <1.78,

1.59 <n ₂ = n ₃ <1.62,

where: R ₃ , R ₄ , R ₅ are the radii of curvature of the third, fourth and fifth optical surfaces;

n ₁ , n ₂ , n ₃ are the refractive indices of the material of the first, second and third lenses for the line e.

This eyepiece has an insufficient angular field in the image space of 46 degrees. and insufficient removal of the exit pupil of 20 mm.

The objective of the invention is the creation of an eyepiece with improved performance with high image quality.

The technical result is an increase in the angular field in the space of images and the removal of the exit pupil with high image quality and technological level.

This is achieved by the fact that in an eyepiece containing two components, the first of which along the beam is a two-lens lens glued from a negative and biconvex lens, the second component is a biconvex lens, and in which the following relations hold:

1.64 <n ₁ <1.78,

1.59 <n ₂ = n ₃ <1.62,

where: n ₁ , n ₂ , n ₃ are the refractive indices of the material of the first, second and third lenses along the beam for line e,

in contrast to the well-known negative lens is biconcave, and there are relations:

| R ₄ | <| R ₅ |,

| R ₂ | = | R ₃ | = | R ₄ |,

where: R ₂ , R ₃ , R ₄ , R ₅ are the radii of the second, third, fourth and fifth optical surfaces.

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 a biconcave lens 1 and a biconvex lens 2, the second is a single biconvex lens 3. The exit pupil is located behind the lens 3.

The eyepiece works as follows.

In front of the lens 1, in the front focus is the plane of objects, the image of which behind the eyepiece is at infinity and is examined by the observer's eye located behind the lens 3.

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

Table 1 Radius mm Thickness mm Glass mark Refractive index n _e Coeff. variances ν _e Light diameter mm R ₁ = -120.23 26 d ₁ = 2.1 TF5 1.761712 27.32 R ₂ = 26.55 27.6 d ₂ = 11 Tk16 1,615192 58.09 R ₃ = -26.55 28.8 d ₃ = 0.15 one R ₄ = 26.55 28 d ₄ = 7 Tk16 1,615192 58.09 R ₅ = -324.3 26.6

The calculated eyepiece has the following characteristics:

Eyepiece focal length f ' 24.85 mm Front focal length 15.16 mm Exit pupil diameter 5,6 mm Relative hole 1: 4.44 Angular field in image space 51 deg. Exit pupil removal 24 mm

Table 2 shows the aberrations of the calculated eyepiece in the reverse ray path for λ = 546 nm.

table 2 Type of aberration Suggested eyepiece (no more) Transverse spherical aberration for a point on the axis with a relative aperture of 1: 4.44 0.025 mm Transverse aberration of a wide inclined beam in the meridional section for a field of view of 2W-51 degrees. 0.157 mm Transverse aberration of a wide inclined beam in a sagittal section for a field of view of 2W-51 degrees. 0.116 mm The meridional astigmatic segment X _m for the field of view 2W = 51 degrees. 1.48 mm Sagittal astigmatic segment X _s for the field of view 2W = 51 deg. -0.803 mm Distortion for the field of view 2W = 51 degrees. -8.4%

Thus, as a result of the proposed solution, a technical result is obtained: an eyepiece with an angular field in the image space of 51 degrees is created. when removing the exit pupil of 24 mm, with high image quality and maintaining a high level of manufacturability.

Claims (1)

An eyepiece containing two components, the first of which is a two-lens lens, glued from a negative and biconvex lens, the second component is a biconvex lens, and the relations are:
1.64 <n ₁ <1.78,
1.59 <n ₂ = n ₃ <1.62,
where n ₁ , n ₂ , n ₃ are the refractive indices of the material of the first, second and third lenses for line e,
characterized in that the negative lens is biconcave and there are relations:
| R ₄ | <| R ₅ |,
| R ₂ | = | R ₃ | = | R ₄ |,
where R ₂ , R ₃ , R ₄ , R ₅ are the radii of the second, third, fourth and fifth optical surfaces.