RU2439631C1 - Eyepiece - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: eyepiece comprises a beam splitter prism installed in front of the first lens component, and the following components arranged along with the beam way: a plano-convex single lens facing the space of objects with flat surface, and a tape joint from convexo-convex and negative lenses facing the space of objects with the convexo-convex lens. The negative lens is made of material with dispersion ratio v_D of not more than 30. Positive lenses are made of material with dispersion ratio v_D of at least 60. The beam-splitter prism is made in the form of a cube prism. Optical forces of the single lens and a taped component are selected under the following conditions: φ₁=0.40…0.60φ_eyp, φ₂=0.40…0.60 φ _eyp, where φ _eyp - optical force of the eyepiece.

EFFECT: provision of the possibility of installation into the additional channel of the liquid-crystal eyepiece with simultaneous reduction of dimensions, weight and cost.

4 dwg, 1 tbl

Description

The invention relates to optical instrumentation, namely to high-aperture eyepieces with a remote front focal segment, and can be used in observation devices, including night vision devices with image formation on a CCD matrix. In particular, the invention relates to objects having, in addition to the main channel, an additional channel that is designed to display auxiliary information in the subject plane of the eyepiece.

Known eyepiece containing three components, the first of which is a positive bonding, consisting of a negative and biconvex positive lenses, the second and third are positive and negative lenses. The eyepiece also contains a beam splitting prism located in front of the first component [RU 2155980 - prototype]. The eyepiece is designed to work in the visible region of the spectrum and can be used in devices with an electron-optical converter (EOC).

The eyepiece has the ability to display supporting information in its subject plane through the aforementioned beam splitting prism. To enter auxiliary information (grid, index or other markup), a projection device is included in the additional channel of the beam splitting prism, which allows during operation to change the nature of the additional information entered, and a backlight device. In order to provide the possibility of installing a beam splitting prism, the eyepiece has an enlarged anterior focal length.

According to the description of the invention to patent RU 2155980 the prototype eyepiece has the following technical characteristics.

Angle of field of view in image space (for the main channel) 39.8 ° Front focal segment (without prism) 0.8 f Entrance pupil diameter 6 mm Distortion at the edge of the field of view 3.9% Relative hole 1: 4.3 Pupil discharge 0.9 f Focal length f 26.1 mm Angular aberration not marked Eyepiece consumption ± 4 diopters

The main disadvantage of the prototype is that it has a narrow field of view in an additional channel (only a few degrees) and a relatively short front segment, which does not allow you to install a liquid crystal display in an additional channel. Liquid crystal displays have recently become actively used in modern observational instruments.

In the prototype, it is recommended to use a projection device for the operation of auxiliary information, which requires illumination to work, and this is an additional set of lenses that increases the size, weight and cost of the eyepiece. The indicated parameters are currently of key importance in the design of observational instruments.

In addition, in the prototype for transmitting auxiliary information, the rays pass from the information source through the projection device and the beam splitter prism, fall into the image intensifier plane, and then go back through the prism into the eyepiece. The passage of rays through the projection system and then twice through the prism significantly reduces the efficiency of light transmission and makes it impossible to use modern LCD displays in the eyepiece, the brightness of which is limited by the specification (technology).

In addition, since the pixel size in LCD displays is a few microns (3-10 um), the diagonal of the emitting area is more than 16 mm, the eyepieces designed for use with such displays have increased requirements for correcting angular aberrations.

The objective of the invention is to create an eyepiece, in the additional channel of which an LCD can be installed, while reducing the size, weight and cost of the eyepiece, and thereby ensuring the possibility of using the eyepiece in modern observation devices.

The invention consists in the following.

In the eyepiece containing a bonding consisting of biconvex positive and negative lenses, the negative lens is made of material with a dispersion coefficient V _{D of} not more than 30, a single convex single positive lens and a beam-splitting prism mounted in front of the first component, these lens components are located along the beam in the following sequence: a plano-convex single positive lens facing the space of objects with a flat surface, and then gluing facing the space of DMetI biconvex positive lens, and the beam-splitting prism is designed as a cube prism, the positive lens made of a material having a dispersion coefficient of V _D is not less than 60, and the optical power of a single lens and a cemented component selected from the condition:

φ ₁ = 0.40 ... 0.60 φ _ok

φ ₂ = 0.40 ... 0.60 φ _ok ,

where φ _ok - the optical power of the eyepiece.

The eyepiece according to the invention has the following technical characteristics:

Angle of field of view in image space in both channels 45 ° Front focal segment (without prism) 0.85 f Entrance pupil diameter 6 mm Distortion at the edge of the field of view <5% Relative hole 1: 4 Pupil discharge 0.85 f Focal length 19 mm Angular aberration (for field edge) <1 diopters Eyepiece consumption ± 5 diopters

Due to the achieved optical characteristics (wide field of view and high image quality), the eyepiece can work with an LCD display in an additional channel.

In the proposed design, the image from the LCD displays directly into the eyepiece through the beam-splitting face of the cube-prism without the use of any additional devices (without the projection system and backlight used in the prototype).

LCD displays make it possible to display a large amount of visual information in the observer’s field of view; therefore, LCD displays are increasingly used in the creation of modern observing instruments.

To establish a cube-prism became possible due to the fact that the front focal segment is increased in comparison with the prototype in the inventive eyepiece. An increase in the anterior focal length by 0.05 f increased the diopter consumption of the eyepiece (sharpening) by 25%: from ± 4 diopters to ± 5 dpt.

The use of a cube-prism made it possible to increase the angle of the field of view in the additional channel and make the angle of the field of view in the main and additional channels the same and equal to 45 °.

The proposed eyepiece has a simple design and contains only two components, the first is a positive lens, the second is glued, consisting of positive and negative lenses, in contrast to the prototype, which additionally contains another lens.

Due to the fact that in the proposed eyepiece, the image in the additional channel is transmitted without the use of any intermediate devices, the efficiency of light transmission and the image quality of the auxiliary information have significantly increased, the dimensions, weight and cost of the eyepiece have decreased.

The increase in the anterior segment, the expansion of the field of view in the additional channel and the increase in diopter consumption made it possible to use the inventive eyepiece in conjunction with modern liquid crystal (LCD) displays. The output of a large amount of visual information from LCD displays greatly expands the consumer properties of observation devices.

The invention is illustrated by drawings.

Figure 1 presents the optical scheme of the proposed eyepiece,

figure 2 shows graphs of curvature and astigmatism,

figure 3 is a graph of relative distortion,

figure 4 is a graph of spherical aberrations for a point on the axis.

The linear field of the eyepiece m = 16 mm, indicated on the ordinate scale in the graphs of FIGS. 2 and 3 corresponds to an angular field of the eyepiece of 45 degrees (for both channels).

The scale value of 0.4 mm in the graph of figure 2 corresponds to ~ 1 diopters.

All curves are presented for a wavelength of 587.6 nm.

The optical scheme of the proposed eyepiece (figure 1) consists of a beam-splitting cube-prism 1 and two lens components. The first component is a single positive lens 2, which faces the space of objects with a flat surface, the second is gluing, consisting of a biconvex positive lens 3 and a negative lens 4. Gluing 3, 4 is directed to the space of objects with a biconvex positive lens 3. The eye of the observer is placed in the exit pupil 5.

The following is a table of the design parameters of the eyepiece components.

Surface Radius of curvature Distance between surfaces Glass Diameter Refractive Index (Nd) Dispersion (Vd) An object ∞ one ∞ 1.6 2 ∞ twenty 1.516 64.2 twenty 3 ∞ 1.75 twenty four ∞ 5 1.620 60.3 22 5 -25.63 0.3 22 6 17.79 7 1.589 61.2 twenty 7 -21.82 2.2 1.805 25.4 twenty 8 -380.9 fifteen twenty Image plane ∞ 5.1

Tests and the practice of working with prototypes of the eyepiece made according to these design parameters confirmed the specified technical characteristics and technical result.

The eyepiece works as follows.

The luminous flux from object plane A passes through a beam-splitting cube-prism 1 and lens 2-4 and enters the eye of an observer located in the exit pupil 5 of the eyepiece. Auxiliary information coming from an LCD display located in plane B passes through a beam-splitting cube-prism 1, lens 2-4 and enters the exit pupil 5 simultaneously with the main image from the subject plane A.

To ensure image sharpness when working with the eye, diopter movement is ensured by the entire eyepiece by ± 5 diopters.

Claims (1)

An eyepiece containing a bonding consisting of biconvex positive and negative lenses, wherein the negative lens is made of material with a dispersion coefficient v _{D of} not more than 30, a plano-convex single positive lens and a beam-splitting prism mounted in front of the first lens component, characterized in that said lens components are located along the beam in the following sequence: a flat convex single positive lens facing the space of objects with a flat surface, then gluing, about aschennaya to space objects biconvex positive lens, the beam-splitting prism is designed as a cube prism, the positive lens made of a material having a dispersion coefficient v _D at least 60, and the optical power of a single lens and a cemented component selected from the condition:
φ ₁ = 0.40 ... 0.60 φ _ok
φ ₂ = 0.40 ... 0.60 φ _ok
where φ _ok - the optical power of the eyepiece.

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