RU127951U1 - OPTICAL SYSTEM OF THE PROJECTION ON-BOARD INDICATOR - Google Patents

Abstract

The optical system of the projection on-board indicator, containing a concave spherical beam splitter mirror with a radius of curvature R, a flat beam splitter mirror mounted obliquely to the optical axis, a spherical diffuse-scattering screen, a projection lens consisting of two components and an aperture diaphragm (AD), the first component is made in the form of a single meniscus with negative optical power φ, convex to a spherical diffuse-scattering screen with a radius of curvature R / 2, the second component made of a glued lens with negative optical power φ, and a two-lens element with positive optical power φ, containing a biconcave and biconvex lens, as well as a liquid crystal display and a condenser, characterized in that the aperture diaphragm (AD) is installed between the first and second components in front focus of the second component, a glued lens with a positive optical power φ inserted between the aperture diaphragm (AD) and a glued lens with a negative optical power φ, and a suit lens with a positive optical power φ, turned concave to a spherical diffuse-scattering screen, mounted behind a glued lens with a negative optical power φ, and a biconcave and biconvex lens of a two-lens element with a positive optical power φ are installed with an air gap, while the optical power of the lenses satisfy condition 0 , 2 <| φφ \ <0.30.4 <| φφ \ <0.50.1 <φφ <0.250.9 <φφ <1.10.45 <φφ <0.6, where φ is the total optical power of the lens .

Description

The proposed utility model relates to optical instrumentation and can be used in the aviation industry, in particular for aviation optical sights, display devices in front of the windshield of the cockpit, etc.

On-board display devices are an optical system that provides overlay on the real picture of the external space of various symbolic information perceived by the pilot due to the positive brightness contrast. The overlay effect is ensured by the use of optical beam splitters in the indicator, partially transmitting light rays from external space and reflecting light rays coming from a collimated imaginary image of the information picture. The image source for the information picture is high-brightness screens, the displays of which are aligned with the front focal surface of the optical system of the projection-based on-board indicator (OSBI).

The main requirements for OSPB are:

- A large output field of view of at least 30 ° horizontally and 20 ° vertically, which determines the informative capabilities of the indicator;

- Significant removal of the entrance pupil - the plane of the pilot’s eye from the reflecting beam splitter (combiner) at a distance of more than 300 mm;

- Significant size of the entrance pupil is not less than 160 mm horizontally and 100 mm vertically, providing the ability to observe information when the pilot's head moves within Δx = 80 mm horizontally and Δy = ± 50 mm vertically;

- Minimal distortion distortion of the image of objects; - The need to use as a display for the formation of the image of symbolic or other information - liquid crystal panels ZhSK displays;

- The constructive ability to withdraw the combiner from the path of rays to ensure the observation of objects only in the space of objects.

There are a number of OSPBI [1-2] installed in front of the windshield of the cockpit.

In known optical systems [1-2], flat surfaces are used as a reflecting beam splitting mirror (combiner), and OSPBI is collimator lenses with luminous screens installed in their focal planes.

The disadvantages of such optical systems are that they do not provide the required large angular fields of view due to the limited size of the lens. Indeed, the angular field 2 ° C is related to the diameter (D) of the lens by the ratio:

D = 2Stg (ω) × D _int.sp , where

S is the distance from the pilot’s eyes to the lens, D _{in sp} is the diameter of the entrance pupil.

Since the value is S = 300 mm, already at 2ω = 30 ° there should be a lens diameter D≥160-270 mm.

The optical system of the projection on-board indicator [3] is made in the form of a concave spherical beam splitting mirror, a flat beam splitting mirror mounted obliquely to the optical axis, a projection lens and a display containing a cathode ray tube (CRT).

The disadvantage of this OSPBI is the inability to use an LCD display to form an information image.

The disadvantage of OSPBI [4], containing a beam-splitting concave spherical mirror and a flat beam-splitting mirror mounted obliquely to the optical axis, diffusely scattering screen, projection lens and ZhSK display, is a small angular field of view.

The disadvantage of OSPBI [5], containing a beam-splitting concave spherical mirror and a flat beam-splitting mirror mounted obliquely to the optical axis, diffusely scattering screen, projection lens and display, is a small angular field of view and the size of the incoming pupil.

The disadvantage of OSPBI [6], which contains a beam-splitting concave spherical mirror and a flat mirror mounted obliquely to the optical axis, a projection lens, and an ZhSK display, is the small size of the entrance pupil.

The closest technical solution to the proposed utility model is OSPBI [7]. "

The optical system of the projection on-board indicator contains a concave spherical beam splitting mirror with a radius of curvature R, a flat beam splitting mirror mounted obliquely to the optical axis, a spherical diffuse-scattering screen, a projection lens, a liquid crystal display, and a condenser.

The projection lens consists of two components and an aperture diaphragm (AD), the first of the components is a single meniscus with negative optical power φ _I convex to a spherical diffuse scattering screen with a radius of curvature R / 2, the second component is made of a glued lens with a negative optical with a power of φ _{II, 1} and a two-lens element with a positive optical power of φ _{II, 2} containing biconcave and biconvex lenses glued together.

The disadvantages of OSPBI are the possibility of its use only for small distances from the pilot’s eyes to the beam splitting mirror, i.e. for values of S <50 mm; the inability to move the pilot’s head during the observation of symbolic information due to the strictly fixed position of the OSPB relative to the pilot’s head.

The main task, which the utility model is aimed at, is to ensure flight safety by eliminating the loss of information from the display when the pilot’s head moves along the optical axis and perpendicular to it due to the large size of the OSBI entrance pupil and the distance from it to the combiner.

To solve this problem, we propose an optical system for the projection on-board indicator, which, like the prototype, contains a concave spherical beam splitter with a radius of curvature R, a flat beam splitter mounted obliquely to the optical axis, a spherical diffuse-scattering screen, a projection lens consisting of two components and an aperture diaphragm (AD), the first component is configured as a single meniscus negative refractive power φ _I, to the spherical convexity facing diff znorasseivayuschemu screen with a curvature radius R / 2, the second component is made of a glued lens with negative refractive power φ _{II, 1,} and two-lens element with positive optical power φ _{II, 2} containing biconcave and biconvex lenses, as well as a liquid crystal display and a condenser ,.

Unlike the prototype, in the proposed optical system of the projection on-board indicator, an aperture diaphragm (AD) is installed between the first and second components in the front focus of the second component, a glued lens with a positive optical power φ _{II, 3} installed between the aperture diaphragm (AD) is introduced into the second component and a glued lens with negative optical power φ _{II, 1} , and a meniscus lens with positive optical power φ _{II, 4} , facing concavity to a spherical diffuse-scattering screen mounted behind the glue a lens with negative optical power φ _{II, 1} , and biconcave and biconvex lenses of a two-lens element with positive optical power φ _{II, 2 are} installed with an air gap, while the optical forces of the lenses satisfy the condition:

0.2 <| φ _{I /} φ _equiv | <0.3 _|

0.4 <| φ _{II, 1 /} φ _equiv | <0.5

0.1 <φ _{II, 2 /} φ _equiv <0.25

0.9 <φ _{II, 3 /} φ _equiv <1.1

0.45 <φ _{II, 4 /} φ _equiv <0.6

where φ _eq is the equivalent optical power of the lens as a whole.

The essence of the proposed optical system for the projection on-board indicator is as follows.

Installing an aperture diaphragm (AD) between the first and second components in the front focus of the second component provides a telecentric path of the main rays in the space of the liquid crystal display.

Polarized radiation from the source after the parallel-beam condenser illuminates the liquid crystal display and, after reflection from its surface, fills the aperture diaphragm (AD) of the projection lens, creating the greatest and most uniform brightness of the liquid crystal display.

The introduction into the second component between the aperture diaphragm (AD) and the negative lens optical power φ _{II, 1 of the} positive lens AF _{II, 3} , and behind the negative optical lens φ _{II, 1 of the} positive meniscus lens φ _{II, 4} , facing concavity to the spherical diffuse screen, allowed to increase the aperture of the lens in the space of the liquid crystal display and thereby increase the illumination of the image on the spherical diffuse screen, introduced There were positive aberrations to whom, astigmatism, increase chromatism and negative position chromatism, which made it possible to compensate for the aberrations introduced by the other projection lenses.

The installation of a biconcave and biconvex lens of a two-lens element with a positive optical power of φ _{II, 2} s, and an air gap made it possible to eliminate the chromaticity of position and magnification, as well as astigmatism.

The implementation of lenses with optical powers that satisfy the condition:

0.2 <| φ _{I /} φ _equiv | <0.3 _|

0.4 <| φ _{II, 1 /} φ _equiv | <0.5

0.1 <φ _{II, 2 /} φ _equiv <0.25

0.9 <φ _{II, 3 /} φ _equiv <1.1

0.45 <φ _{II, 4 /} φ _equiv <0.6

where φ _equiv is the equivalent optical power of the lens as a whole, it was possible to obtain the specified surface curvature of the spherical diffuse-scattering screen equal to the focal length (f) of the concave spherical beam splitter mirror, f = R / 2, where R is the radius of curvature of the concave spherical beam splitter mirror and compensate for the distortion of the projection a lens on a spherical diffuser.

The essence of the proposed utility model is illustrated by the drawing, where Fig. 1 shows a diagram of the optical system of the projection on-board indicator, and the Appendix, which shows the design parameters and optical characteristics of a particular sample.

The proposed optical system for the projection on-board indicator consists of a concave spherical beam splitter mirror 1, with a beam splitter reflective surface 2 of radius R, a plane beam splitter mirror 3 with a beam splitter reflective surface 4, a spherical diffuse diffusion screen 5 with a radius R / 2, a projection lens consisting of the first component made in the form of a single meniscus 6 with negative optical power φ _I convex to a spherical diffuse-scattering screen 5, and aperture diaphragm (AD) 7 and a second component containing a glued lens 8 with negative optical power φ _{II, 1} , a two-lens element 9 with positive optical power φ _{II, 2} , made in the form of a biconcave and biconvex lenses mounted with an air gap, a glued lens 10 with a positive optical power φ _{II, 3} , a meniscus lens 11 with a positive optical power φ _{II, 4} , facing a concavity to a spherical diffuse-scattering screen 5.

The liquid crystal display 12 is illuminated by a source 13 using a capacitor 14 and a polarizing prism 15.

The pupil of the eye 16 can move horizontally by ± Δx and vertically (in the plane of the drawing) ± Δy in the plane of the entrance pupil 17, observing the object 18 and simultaneously displaying symbol information from the liquid crystal display 12 on a spherical diffusely scattering screen 5.

The optical system of the projection on-board indicator is as follows.

In the reverse course of the rays, parallel beams of light from each pilot’s eye, with a diameter equal to the diameter of the entrance pupil of the eye (2-4 mm), after reflection from a concave spherical mirror 1 and a flat beam splitter mirror 3, focuses on the spherical surface of the diffusely scattering screen 5 located at the focus of the concave spherical mirror 1.

The projection lens 6-11 mates the surface of the liquid crystal display 12 with the surface of the diffusely scattering screen 5. Thus, the optical system of the projection on-board indicator is a monocular wide-angle magnifier, in the focus of which a diffusely scattering screen 5 is mounted, onto which information from the liquid crystal display 12 is projected. The pilot simultaneously observes the surface of the diffusely scattering screen 5 against the background of an external object 18.

To illuminate the liquid crystal display 12, a lighting system is used consisting of a radiation source (LED) 13 located at the focus of the condenser 14. A parallel radiation beam after the condenser 14 is reflected from the polarizing surface of the prism 15, which reflects the P polarization and transmits S-polarization. The P radiation reflected from the liquid crystal display 12 is rotated 90 ° and is focused in the plane of the aperture diaphragm (AD) 7, filling its diameter. The projection lens 6-11 operates with a magnification of 5.7 ^x for the attached example in the direction of the diffusely scattering screen 5.

, например, при R=360 мм α≥24°, или апертура sinα≥0,4.The largest apertures at which the polarization of the prism 15 is provided does not exceed 0.13-0.15. With an increase of 5.7 ^x , the aperture in the image space on the diffusely scattering screen 5 is 0.02-, 025. To ensure the possibility of observing information when the pilot’s head is shifted by Δх = ± 80 mm, Δу = ± 50 mm, it is required that the diffusion-scattering screen 5 has a scattering aperture of at least

for example, at R = 360 mm α≥24 °, or the aperture sinα≥0.4.

To ensure the aperture sinα≥0.4-0-0.5, a diffusely scattering screen 5 is used, which converts the 0.025 aperture incident on it after radiation passes through it to 0.4-0.5.

As an example, the optical system of the projection on-board indicator is shown with the following parameters given in the Appendix.

1. Russian Federation, patent for invention No. 2358304, IPC: G02B 27/08, G02B 27/01, publ. 06/10/2009

2. Russian Federation, patent for invention No. 2358303, IPC: G02B 27/08, G02B 27/01, publ. 06/10/2009

3. USA, patent for invention No. 5907416, IPC: G02B 27/01, G09B 9/30, publ. 05/25/1999

4. France, patent for invention No. 2858068, IPC: G02B 27/01, publ. January 28, 2005

5. United States, patent for the invention No. 7391574, IPC: G02B 27/14, publ. September 20, 2007

6. United States, patent for the invention No. 8089568, IPC: G02B 27/01, G02F 1/1335, publ. 01/03/2012

7. USA, patent for invention No. 5483307, IPC: G02B 26/08, G02B 27/01, G02B 27/02, G02B 27/00, publ. 01/09/1996, the prototype.

Claims (1)

The optical system of the projection on-board indicator, containing a concave spherical beam splitter mirror with a radius of curvature R, a flat beam splitter mirror mounted obliquely to the optical axis, a spherical diffuse-scattering screen, a projection lens consisting of two components and an aperture diaphragm (AD), the first component is made in the form of a single meniscus with negative optical power φ _I , convex to a spherical diffuse-scattering screen with a radius of curvature R / 2, the second component in made of a glued lens with negative optical power φ _{II, 1} , and a two-lens element with positive optical power φ _{II, 2} , containing a biconcave and biconvex lens, as well as a liquid crystal display and a condenser, characterized in that the aperture diaphragm (AD) is installed between the first and the second components in the front focus of the second component, a glued lens with a positive optical power φ _{II, 3} inserted between the aperture diaphragm (AD) and a glued lens with a negative optical sludge φ _{II, 1} , and a meniscus lens with positive optical power φ _{II, 4} , turned concave to a spherical diffuse-scattering screen, mounted behind a glued lens with negative optical power φ _{II, 1} , with a biconcave and biconvex lens of a two-lens element with positive optical forces φ _{II, 2 are} installed with an air gap, while the optical forces of the lenses satisfy the condition 0.2 <| φ _{I /} φ _EQ \ <0.3 _\ 0.4 <| φ _{II, 1 /} φ _EQ \ <0.5 0.1 <φ _{II, 2 /} φ _EQ <0.25 0.9 <φ _{II, 3 /} φ _EQ <1.1 0.45 <φ _{II, 4 /} φ _EQ <0.6 where φ _eq is the equivalent optical power of the lens as a whole.

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