RU2364902C1 - Collimator indicator system - Google Patents

Abstract

FIELD: physics, optics.

SUBSTANCE: collimator indicator system is intended for display of flight information combined with conditions observed outside cabin. System comprises generator of two-dimensional image with radiator 2 in the form of liquid crystal panel, projection objective 3 with decentered optic elements and combiner 4. Optical system of projection objective 3 consists of three lens groups and optical wedge, optical axes of which are displaced and/or turned in meridional plane. Combiner 4 is made in the form of plano-convex lens 5 and plano-concave lens 6 glued along spherical surfaces with multilayer dielectric beam-splitter coating 7 applied on surface of gluing, which selectively reflects radiation of liquid crystal in narrow range of wave lengths and transmits passing light of visible wave range.

EFFECT: expansion of visual field and higher comfort of perception at considerable distance from output lens of projection objective.

3 cl, 5 dwg

Description

The invention relates to techniques for projection systems for displaying flight information and can be used primarily for cabin-based aircraft.

Current trends in the development of aviation technology, piloting tactics and the use of technical means in flight lead to an ever-increasing information saturation of the entire process, a constant increase in the requirements for speed and quality of decision-making, and an increase in the cost of error. This means the need to improve the delivery of information for the pilot, creating for him, with all the speed of changing the situation, the most comfortable conditions of perception, improving concentration, reducing fatigue and, as a consequence, reducing the likelihood of an incorrect decision.

Of paramount importance for solving this problem is the technical level of cab equipment. A special place is occupied by a collimator-type cabin indicator, that is, an indicator that is looked at with a raised head, without lowering the gaze to the dashboard.

The design of the collimator indicator systems significantly depends on the organization of the working space of the cabin. For the implementation of the indicator systems under consideration, various solutions are known based on one or more reflective / transmission surfaces (US 6567014 B1, 05.20.2003; US 5640275 06/17/1997; US 4669810, 06/02/1987; US 4407564, 10/04/1983). When optical rays pass through several reflecting / transmitting surfaces, additional image distortions occur, to compensate for which decentralized optical elements are included in the projection lens, that is, elements having off-axis displacement of lenses or groups of lenses, the inclination of some surfaces or lenses.

Closest to the present invention in essence and the achieved result is a collimator indicator system with decentralized optical elements according to the patent US 5640275, 06/17/1997. The use of a combiner (a beam-splitting optical element) using holographic elements in this invention is a significant drawback, since it requires the use of special expensive technology for its manufacture and special operating conditions on aircraft.

The problem to which this invention is directed, is to create a simple collimator display system cabin-based aircraft for general purposes with high image quality.

The technical result achieved by using the present invention is to expand the field of view of the indicator system with comfortable sensing conditions at a considerable distance from the output lens of the projection lens, as well as to reduce the cost of the system.

The problem is achieved with the achievement of the above technical result is solved by the fact that in the collimator indicator system containing a two-dimensional image generator with an emitter located in the focal plane of the projection lens with decentralized optical elements and a combiner, the emitter is made in the form of a liquid crystal (LCD) panel with a backlight system on LEDs with radiation in a narrow wavelength range, a two-dimensional image generator is configured to introduce distortion prediction In the image formed on the screen of the LCD panel, the combiner is inclined to the axis of sight and is configured to combine the image of the viewing space with the image from the projection lens, which is located along the axis of sight reflected from the combiner and is separated from it, the optical system of the projection lens consists of consecutively arranged with respect to the combiner of three lens groups and an optical wedge, the first lens group consists of a first biconvex lens and a second double a convex lens and a convex-concave lens, the second lens group is separated from the first lens group by an aperture diaphragm located in the middle of the air gap between them, and contains the first biconcave lens, a lens with a cylindrical surface and a gluing of the second biconcave lens and biconvex lens, the third lens group contains biconvex and convex-concave lenses, and the optical wedge is located in the gap between the third lens group and the emitter, while the optical axis of the first lens group is shifted to of the meridional plane parallel to the left with respect to the axis of sight reflected from the combiner, the optical axis of the second lens group is shifted in the meridional plane parallel to the left with respect to the optical axis of the first group, the optical axis of the biconvex lens of the third group is shifted in the meridional plane parallel to the right with respect to the optical axis of the second group, the optical axis is convex -concave lens of the third group is offset relative to the optical axis of the biconvex lens in the opposite direction to the same led the cause and is rotated clockwise relative to the axis perpendicular to the meridional plane and passing through the apex of the convex-concave lens, and the optical wedge is deployed clockwise relative to the axis perpendicular to the meridional plane and passing through the middle of the front surface of the optical wedge.

The technical result is also achieved by the fact that:

the combiner is made in the form of plane-convex and plane-concave lenses glued over spherical surfaces with a multilayer dielectric beam splitting coating applied to the gluing surface, which selectively reflects the radiation of the LCD panel in a narrow wavelength range and transmits transmitted light of the visible wavelength range;

the two-dimensional image generator comprises a series-connected display data receiving unit, a combined image forming unit, a predistorted image forming unit, and an LCD panel.

The expansion of the field of view of the indicator system with comfortable perception conditions, that is, with slight aberrations of the observed image, at a considerable distance from the output lens of the projection lens, is provided by the proposed design of the optical system with decentralized optical elements, the design of the combiner and the use of electronic distortion compensation. The decrease in the cost of the system is due to the possibility of using standard technologies for the production of optical elements of the projection system and the combiner.

The invention is illustrated by drawings, which depict:

figure 1 - geometry of the collimator indicator system;

figure 2 - the design of the optical system;

figure 3 is a view of the distortion of the indicator system before correction;

figure 4 - the course of some light rays in the indicator system;

figure 5 is a structural electrical diagram of a two-dimensional image generator.

In the drawings are indicated:

1 - two-dimensional image generator;

1-1 - block receiving the displayed data;

1-2 - block forming a combined image,

1-3 - unit for generating a predistorted image;

1-4 - LCD panel;

2 - emitter;

3 - projection lens;

4 - combiner;

5 - plano-convex lens of the combiner;

6 - flat-concave lens of the combiner;

7 - the inner beam splitting surface of the combiner;

8 - the first lens group;

9 - the second lens group;

10 - the third lens group;

11 - the first biconvex lens of the first group;

12 - the second biconvex lens of the first group;

13 - convex-concave lens of the first group;

14 - aperture diaphragm;

15 - the first biconcave lens of the second group;

16 - a lens with a cylindrical surface of the second group;

17 - the second biconcave lens of the second group;

18 - biconvex lens of the second group,

19 - biconvex lens of the third group;

20 - convex-concave lens of the third group;

21 - an optical wedge;

22 - axis of sight;

23 - axis of sight reflected from the combiner;

24 - pupil observation area.

The collimator indicator system (see Fig. 1) comprises a two-dimensional image generator 1 with an emitter 2 located in the focal plane of the projection lens 3, and a combiner 4. The projection lens 3 is located along the axis of sight 23, which is the axis of sight 22, broken in accordance with reflection of light from the flat surface of a plano-convex lens 5 of the combiner 4, and is carried away from it by a distance A1. The combiner 4 is inclined to the axis of sight 22 by an angle θ1 and is made in the form of a plano-convex lens 5 and a plane-concave lens 6 coated with a multilayer dielectric beam splitting coating that selectively reflects the radiation of the LCD panel in a narrow wavelength range and transmits transmitted light visible wavelength range.

The combiner 4 provides the ability to offset the projection lens 3 relative to the axis of sight 22 by angle 02, and to combine the observable situation through the combiner with the image from the projection lens 3 without blocking the visibility of the situation with the structural elements of the system outside the field of view of the display channel.

The optical system of the projection lens 3 consists (see FIG. 2) of three lens groups 8, 9 and 10 sequentially arranged relative to the combiner 4 and the optical wedge 21. The first lens group 8 consists of a first biconvex lens 11 and a second biconvex lens 12 assigned therefrom and a convex-concave lens 13. The second lens group 9 is separated from the first lens group by an aperture diaphragm 14 located in the middle of the air gap between them, and contains the first biconcave lens 15 of the second group, the lens 16 with a cylindrical lens rhnostyu and gluing of a biconcave second lens 17 and a biconvex lens 18. The first lens 15 has a biconcave negative force. The generatrix of the cylindrical surface of the lens 16 having negative optical power is oriented perpendicular to the meridional plane. The third lens group 10 contains a biconvex lens 19 and a convex-concave lens 20. An optical wedge 21 is located in the gap between the third lens group 10 and the emitter 2.

The optical axis of the first lens group 8 is offset in the meridional XOY plane by Δ1 parallel to the left with respect to the axis 23. The optical axis of the second lens group 9 is shifted in the meridional XOY plane by Δ2 parallel to the left with respect to the optical axis of the first lens group 8. The optical axis of the biconvex lens 19 of the third the lens group 10 is displaced in the XOY meridional plane by Δ3 parallel to the right relative to the optical axis of the second lens group 9. The optical axis of the convex-concave spherical lens 20 is third th lens group 10 is shifted relative to the optical axis of the second biconvex spherical lens 19 in the opposite direction by the same value Δ3 and rotated clockwise at an angle α1 relative to the axis perpendicular to the meridional plane and passing through the apex of the convex-concave lens 20. The optical wedge 21 is allocated from the third lens group 10 and is rotated clockwise at an angle α2 relative to the axis perpendicular to the meridional plane and passing through the middle of the front surface of the optical wedge.

The course of some rays in the optical system of the projection lens 3 and the combiner 4 is shown in Fig.4. The first lens group 8 provides the development of the field of view within the given dimensions of the combiner 4 and its distance from the projection lens 3. Aperture diaphragm 14 ensures the minimization of flare due to cutting off spurious beams of rays. The second lens group 9 provides correction of the aberration of a wide inclined beam of rays, astigmatism and distortion, while the first biconcave spherical lens 15 together with the biconcave lens 17 corrects the curvature of the field, the lens 16 with a cylindrical surface corrects astigmatism, and the gluing of the biconcave and biconvex lenses 17 and 18 minimizes coma aberration and spherical aberration. The third lens group 10 ensures the development of the relative aperture of the system, reducing, together with the wedge 21, the tilt of the image, as well as correcting astigmatism, distortion and coma.

The set of elements of the indicator system focuses on infinity the image transmitted to the pilot, and ensures its overlap on the cockpit environment visible to the pilot. The design of the proposed indicator system provides image formation with the necessary level of correction of all aberrations, except distortion. The distortion of the optical system is an aberration, which does not affect the sharpness of the image, but distorts its shape. For the proposed indicator system, distortion to compensation is shown in Fig. 3, which shows the transformation of a uniform grid in the pupil observation zone 24 into a grid on the surface of the emitter 2. The dimensions of the field of view are normalized to its maximum value along the Z axis. The values of the angles of the field of view are shown in brackets at the entrance for extreme rays. Additional distortion compensation is carried out electronically due to the formation of a predistorted image in the generator 1.

The two-dimensional image generator 1 contains (see FIG. 5) a series-connected display data receiving unit 1-1, a combined image forming unit 1-2, a predistorted image forming unit 1-3, and an LCD panel 1-4.

The LCD panel 1-4 has an LED backlight system that provides sufficient brightness and uniformity of the image on the LCD panel screen (see, for example, RU 46865 U, June 27, 2005). For indicator systems on aircraft, as a rule, LEDs with radiation in a narrow wavelength band of the green part of the spectrum are used.

The displayed data receiving unit 1-1 is an interface unit and provides data reception from environmental sensors, for example, an airborne radar, a television camera, as well as airborne position sensors and flight parameters of an aircraft, aircraft collision avoidance systems, or other aircraft. Block 1-2 provides the formation of an image signal containing data from one of the sensors or any combination thereof. Block 1-3 contains a memory block of distortion compensation coefficients and a computer that, taking into account these coefficients, generates a predistorted image that is displayed on the LCD panel 1-4. After the predistorted image passes through the optical system 3 and the combiner 4, an undistorted image is formed in the pilot's field of view.

Collimator indicator system operates as follows.

The combiner 4 is placed in front of the windshield of the aircraft cockpit, and the projection lens 3 on the ceiling above the helmet of the pilot in accordance with the placement geometry shown in Fig. 1. The angle θ2 is selected from the condition of maximum removal of the output lens 11 of the projection lens 3 from the helmet of the pilot when the desired image quality is achieved.

The flight information selected by the pilot for display is generated on the screen of the LCD panel 1-4 and is emitted in a narrow wavelength band of the green part of the spectrum, determined by the type of LED, for example from 515 to 535 nm. The screen is located in the focal plane of the projection lens 3, which projects the image through the combiner 4 in the field of view of the pilot. The light rays forming the image are reflected from the inner beam splitter surface 7 of the combiner, and due to its inclination at an angle of 01 with respect to line of sight 22, they fall into the pilot’s field of vision, where the image formed on the LCD panel screen is combined with the image of the cockpit environment, observed through the combiner 4. Combiner 4 provides an integrated reflection coefficient of the image in the wavelength range from 500 to 550 nm of not less than 0.7 and transmits transmitted light of the visible wave range with an integral coefficient ohm transmission of not less than 0.85. The pilot can simultaneously observe the cockpit situation and the selected flight information.

A prototype helicopter-based system has been developed, which with a 2.5-inch LCD panel matrix size and a projection lens length of not more than 240 mm provides:

field of view - not less than ± 12 ° horizontally and ± 8 ° vertically;

the size of the pupil observation zone is at least 110 mm horizontally and 90 mm vertically;

the distance from the projection lens to the combiner A1 is not less than 350 mm;

removal of the observer's eyes from the combiner A2 - up to 400 mm;

distortion no more than 5%;

resolution - no more than 3 arc minutes in the center and no more than 10 arc minutes at the edge of the field of view.

Thus, the proposed collimator indicator system provides the possibility of observing in the field of view of the system of high-quality images of flight information against the background of the observable cockpit space.

The production of optical elements for the projection lens and the combiner of the proposed system is possible using standard technologies. The proposed system can be used in other avionics products, as well as in sea and land based products.

Claims (3)

1. A collimator indicator system containing a two-dimensional image generator with an emitter located in the focal plane of the projection lens with decentralized optical elements, and a combiner, characterized in that the emitter is made in the form of a liquid crystal (LCD) panel with a backlight system on LEDs with radiation in a narrow range wavelengths, a two-dimensional image generator is configured to introduce distortion predistortions into the image formed on the LCD panel screen, the combiner is inclined to about and sighting and is configured to combine the image of the surveyed space with the image from the projection lens, which is located along the axis of sight reflected from the combiner, and is separated from it, the optical system of the projection lens consists of three lens groups and an optical wedge arranged in series relative to the combiner, the first lens the group consists of a first biconvex lens and a second biconvex lens and a convex-concave lens assigned therefrom, the second lens group is separated t of the first lens group with an aperture diaphragm located in the middle of the air gap between them, and contains the first biconcave lens, a lens with a cylindrical surface and a gluing of the second biconcave lens and biconvex lens, the third lens group contains a biconvex and convex-concave lens, and the optical wedge is located in the gap between the third lens group and the emitter, while the optical axis of the first lens group is shifted in the meridional plane parallel to the left relative to the axis I, reflected from the combiner, the optical axis of the second lens group is offset in the meridional plane parallel to the left relative to the optical axis of the first group, the optical axis of the biconvex lens of the third group is offset parallel to the right in relation to the optical axis of the second group, the optical axis of the convex-concave lens of the third group is offset relative to the optical axis of the biconvex lens in the opposite direction by the same amount and rotated clockwise relative to the axis, perpendicular of the meridional plane and passing through the apex of the convex-concave lens, and the optical wedge is rotated clockwise relative to the axis perpendicular to the meridional plane and passing through the middle of the front surface of the optical wedge. 2. The system according to claim 1, characterized in that the combiner is made in the form of plane-convex and plano-concave lenses glued on spherical surfaces with a multilayer dielectric beam splitting coating that selectively reflects the radiation of the LCD panel in a narrow wavelength range and transmits visible light range of waves. 3. The system according to claim 1, characterized in that the two-dimensional image generator comprises serially connected display data receiving unit, a combined image forming unit, a predistorted image forming unit, and an LCD panel.

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