RU2586097C1 - Helmet-mounted wide-angle collimating optical display system - Google Patents

Abstract

FIELD: optics.

SUBSTANCE: helmet-mounted wide-angle collimating optical system comprises display projector, including liquid crystal display, lens projection system consisting of three components, two-mirror component and splitting collimating concave mirror, connecting image from outer space and from liquid crystal display. Projection lens system made with telecentric stroke of main beams in space of liquid crystal display. At that, first component comprises biconvex lens and positive meniscus, second component is made of positive and negative meniscus and negative hyperbolic biconcave lens. Third component is made from positive meniscus and biconvex lens.

EFFECT: technical result consists in simplifying design of protective glass helmet-mounted system, providing telecentric main beams in space of liquid crystal display, increase brightness due to illuminate liquid crystal display reflected polarised beams, normal to display surface, and provision of high quality on entire field of entrance to pupil diameter of not less than 14 mm.

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Description

The present invention relates to optical instrumentation and can be used, for example, in the aviation industry, in particular for display devices on a pilot helmet, etc.

The helmet-mounted wide-angle collimator display optical system (NSKDOK) is a system that allows the pilot to simultaneously observe the real space and the information picture from the display, visible through the optical system with a beam-splitting concave collimating mirror (combiner), while the sighting axis of the observer (pilot) and the optical axis of the system from the display combined. At the same time, the combiner is at the same time part of the safety glass of the pilot's helmet.

Thus, NShKDOK works on the principle of a magnifier or an eyepiece, i.e. forms a display image for practical infinity. As imaging devices, miniature cathode ray tubes (CRTs) or more promising matrix displays based on LCOS technology (liguid Crystal on Silicon) - a liquid crystal display - are used.

The main requirements for NShKDOK are:

- a large angular field in the space of the object: at least 21 ° in the horizontal direction and 18 ° in the vertical direction;

- significant removal of the entrance pupil — the observer’s eyes from the object — at least 70 mm from the sight glass — the combiner, and the diameter of the entrance pupil is ≥ 12-14 mm;

- minimized weight of the entire device, (less than 150 g);

- high resolution throughout the field: 1280 pixels or more per line;

- high transmittance and the same color of the observed external space;

- the absence of distortion distortion of the image of the object on the liquid crystal display;

- telecentric ray path in the space of the liquid crystal display and a large rear segment for the placement of elements of the lighting system;

- lack of optical components in the space between the eye of the observer and the combiner;

- the implementation of the combiner spherical shape as part of a protective spherical glass.

A number of helmet-mounted wide-angle display optical systems (NSHDOS) are known.

NShDOS [1] contains a liquid crystal display (LCD), a projector and a beam-splitting collimating mirror - a combiner, which is part of the protective shut-off glass of the crest.

The disadvantages of such NShDOS are a small rear segment, which does not allow to establish a polarizing prism and a reflective reflective LCD system, the presence of an optical component between the observer's eye and the combiner.

In NShDOS [1], only a passing LCD is used, whose energy brightness is lower than in reflecting LCDs. The beam-splitting collimating concave mirror (combiner) has a complex aspherical shape, which is not technologically advanced to manufacture and requires precise adjustment according to the following projection system. In addition, the layout of the NShDOS is such that its dimensions are quite large.

The closest technical solution to the claimed invention is NShDOS [2].

NShDOS consists of a projector, which includes a liquid crystal display arranged sequentially along the light rays, a lens projection system consisting of three components, the first of which is single-lens, and the second and third components are double-lens, a two-mirror component with a Z-shaped central beam, made of meniscus lenses with concave and convex surfaces, respectively, with internal mirror surfaces, and a beam-splitting collimating concave mirror (comb HEPA) connecting the image from the outside space and from the LCD.

The disadvantages of NShDOS are:

- the lack of telecentric rays in the space of the liquid crystal display, which does not allow to establish a polarizing prism, and the lighting system limits the energy brightness of the LCD;

- a complex aspherical (elliptical) form of the combiner, which causes increased requirements for the accuracy of the installation of the projector and its non-upsetting during operation.

The main objective of the invention is to simplify the design of the protective glass of the helmet-mounted system, ensure the telecentric path of the main rays in the space of the liquid crystal display, increase the brightness by illuminating the liquid crystal display with reflected polarizing rays normal to the display surface, and ensure high quality throughout the field with an entrance pupil diameter of at least 14 mm.

To solve this problem, a helmet-mounted wide-angle collimator display optical system is proposed, which, like the prototype, contains a projector that includes a liquid crystal display arranged in series along the light rays, a lens projection system consisting of three components, a two-mirror component made of meniscus lenses with concave and convex surfaces, respectively, with internal mirror surfaces with a Z-shaped stroke of the central beam, and a beam splitting collie iruyuschee concave mirror connecting the image from the external space and to liquid crystal display.

Unlike the prototype, in the present invention, the lens projection system is made with a telecentric path of the main rays in the space of the liquid crystal display, while its first component is made with optical power φ ₁ and contains a biconvex lens and a positive meniscus convex to the liquid crystal display, is shifted by δ _y1 to the central axis, the second component having an optical power φ ₂ is made of a positive meniscus hyperbolic, concave facing to the liquid crystal display, the offset axis of the first component at δ _y21 and negative hyperbolic biconcave lens offset from the axis of the positive hyperbolic meniscus at δ _V22, and is inclined at an angle α _22, a third component having an optical power φ ₃ is made of a positive meniscus facing concavity to the liquid crystal display, and a biconvex lens, tilted by an angle α ₃ relative to the vertex of the concave surface of the negative hyperbolic biconcave lens of the second component and offset from the axis of the negative hyperbolic biconcave lens by δ _y3 moreover, the two-mirror component with a Z-shaped path of the central beam with an optical power of φ _{4 is} set at an angle α ₄₁ and α ₄₂ to the central axis, and the beam-splitting collimating concave mirror is made spherical with the radius of the reflecting surface R ₀ inclined at an angle α ₀ to the central axis while the optical forces, tilt angles and displacement of the components satisfy the conditions:

where φ is the equivalent optical power of the helmet-mounted wide-angle collimator display optical system.

In addition, a polarizing beam splitting prism is installed between the liquid crystal display and the projector, which reflects one of the polarizations of the radiation and transmits the other, and an LED lighting collimator.

The essence of the invention lies in the fact that the addition of the lens of the projection system with telemetry swing principal rays in the space of a liquid crystal display, made in the form of three two lens components with optical powers φ _1, φ _2, φ _3, offset by δ _y1, δ _y21, δ _V22 , δ _y3 and inclined at angles α ₂₁ , α ₃ , respectively, the implementation of a two-mirror component with optical power φ ₄ , each of the mirrors of which is a meniscus lens with concave and convex surfaces, respectively, with internal mirror surfaces mounted at an angle of α ₄₁ and α ₄₂ to the central axis, a beam-splitting collimating concave spherical mirror with a radius R ₀ and inclined at an angle α ₀ to the central axis, and the installation of a polarizing beam-splitting prism reflecting one of the polarizations of the radiation normal to the LCD and transmitting other polarizing radiation reflected from the LCD and the LED lighting collimator, it was possible to provide correction of aberrations by introducing an inclined spherical collimating mirror (combiner) and increase LCD brightness.

A spherical mirror operating at an angle α ₀ introduces asymmetric aberrations such as coma and astigmatism throughout the image field, as well as a form of distortion.

Astigmatism ΔZ is proportional to

,

- астигматические отрезки в меридиональной и сагиттальной плоскостях, ω - угол отклонения луча от α₀ - угловое поле.Where

,

- astigmatic segments in the meridional and sagittal planes, ω is the beam deviation angle from α ₀ is the angular field.

For the central beam, the angle i = 0. When the observer’s eye position is shifted in vertical and horizontal positions by ΔX, ΔY, and also when the angular field ω changes, astigmatism takes different values.

Another aberration that occurs in this decentralized system is a form of distortion (parallax).

Parallax ΔX ′, ΔY ′ is determined for each fixed field angle - ω as the difference of coordinates on the display.

where X ′ _{ΔX, ΔY} , Y ′ _{ΔX, ΔY} is the coordinate value on the display with an angular field ω, for the coordinates of the position of the eye on the pupil ΔX, ΔY; X ′ _{ΔX = 0, ΔY = 0} , Y ′ _{ΔX = 0 ΔY = 0} - coordinate values on the display at an angular field ω, for the eye position coordinate ΔX = ΔY = 0, i.e. the eye is located in the center of the pupil.

It is important for the optimal operation of NSKDOS that the value of the angular parallax in the space of the observer's eye did not exceed values more than 12 ′.

The implementation of the projection lens system of three components with the optical forces φ ₁ , φ ₂ , φ ₃ made it possible to correct the curvature of the image, to ensure the telecentric path of the main rays in the LCD space and a large rear segment for installing a polarizing prism.

The offset δ _y1 , δ _y21 , δ _y22 , δ _y3 and the tilts of the second lens of the second component at an angle of α ₂₂ and the third component at an angle of α ₃ made it possible to eliminate decentering and minimize parallax.

The implementation of a two-mirror component with an optical power of φ ₄ , its implementation from meniscus lenses with concave and convex surfaces with internal mirror surfaces, its construction in a Z-shaped pattern with angles α ₄₁ , α ₄₂ eliminated the astigmatism of a spherical beam splitting collimating mirror (combiner).

The execution of the first component from the biconvex lens and the positive meniscus convex to the LCD, the second component from the positive meniscus convex to the LCD, and the negative meniscus convex to the LCD, the third component from the positive concave to LCD, and the biconvex eliminate spherical aberration and residual field aberrations of coma and astigmatism.

The implementation of the lighting system, consisting of an LED lighting collimator, i.e. from the radiation source of the LED and the lens collimator, which forms a parallel beam of radiation, a polarizing beam splitter that transmits P-polarization and reflects S-polarization, allowed the LCD to be illuminated by rays perpendicular to its surface, and to direct the radiation from the LCD through the optical system of the projector into the entrance pupil (observer’s eye ), providing the highest brightness LCD.

The essence of the claimed invention is illustrated by the drawing, which shows the helmet-mounted wide-angle collimator display optical system, and the Appendix, which shows the parameters and optical characteristics of a particular sample.

The proposed helmet-mounted wide-angle collimator display optical system consists of a projector 1, including a liquid crystal display (LCD) 2, a LED lens collimator 3, a polarizing beam-splitting prism 4, a lens projection system 5 made of the first component 6, containing a biconvex lens 7 and a positive meniscus 8, convex to the liquid crystal display 2, of the second component 9, containing a positive hyperbolic meniscus 10 and a negative hyperbolic two a concave lens 11, a third component 12 containing a positive meniscus 13 and a biconvex lens 14, a two-mirror component 15 containing a meniscus lens 16 with concave surfaces with a mirror surface 17 and a meniscus lens 18 with convex surfaces with a mirror surface 19 and a concave beam splitting collimating spherical mirror 20 with a beam splitting surface 21.

The pupil of the eye 22 can move horizontally by ± ΔX, and vertically by ± ΔY in the plane of the pupil of the system, observing the object 23 in the direction of the line of sight 24.

The operation of the helmet-mounted wide-angle collimator display optical system is as follows.

The lens LED collimator 3 through the beam-splitting surface of the polarization prism 4 of the P-component of the radiation illuminates the surface of the liquid crystal display 2. The liquid crystal display 2 rotates the plane of polarization and the S-radiation from the liquid crystal display 2 passes the beam-splitting surface of the polarizing prism 4.

The lens projection system 5, consisting of I, II and III components - 6, 9, 12 lenses 7, 8, 10, 11, 13, 14, and the two-mirror component 15, consisting of lenses 16 and 18, project the object onto the surface of the liquid crystal display 2 into the focal plane of the reflective surface 21 of the beam splitting collimating mirror 20.

After reflection from the surface 21, parallel beams from each point of the image field enter the pupil of the eye 22 of the observer.

Thus, the helmet-mounted wide-angle collimator display optical system is a monocular wide-angle magnifier, in the focus F ′ of which a liquid crystal display 2 is mounted.

The pilot observes at the same time the surface of the liquid crystal display 2 and the spatial object 23 in the direction of the sight axis 24, i.e. an image of the surface of the liquid crystal display 2 is superimposed on the background of the object 23 and thereby simultaneous observation of the spatial object and the image from the liquid crystal display 2 are provided without parallax with good quality.

INFORMATION SOURCES

1. WO No. 2009/018875, IPC: G02B 27/01, 02/12/2009.

2. WO No. 2009/136393, IPC: G02B 27/01, 12/12/2009 - prototype.

Claims (2)

1. A helmet-mounted wide-angle collimator display optical system mounted on an observer helmet, comprising a projector including a liquid crystal display arranged in series along the light rays, a three-component lens projection system, a two-mirror component made of meniscus lenses with concave and convex surfaces respectively, with internal mirror surfaces with a Z-shaped central beam and a beam-splitting collimating concave mirror, soy inyayuschee image from the outside space and from the liquid crystal display, wherein the lens projection system configured teletsetricheskim course of principal rays in the space of a liquid crystal display, with her first component is made with an optical power φ ₁ and comprises a biconvex lens and a positive meniscus convexity to liquid crystal display biased by

_y1 from the central axis, the second component with optical power

_{2 is} made of a positive hyperbolic meniscus, facing concavity to the liquid crystal display, is offset from the axis of the first component by

_y21 and a negative hyperbolic biconcave lens displaced from the axis of the positive hyperbolic meniscus by

_y22 , and tilted at an angle

₂₂ , and the third component with optical power

_{3 is} made of a positive meniscus, facing concavity to the liquid crystal display, and a biconvex lens, tilted at an angle

₃ relative to the apex of the concave surface of the negative hyperbolic biconcave lens of the second component and is offset from the axis of the negative hyperbolic biconcave lens by

_y3 , moreover, a two-mirror component with a Z-shaped path of the central beam with optical power

₄ mounted at an angle

₄₁ and

₄₂ to the central axis, and the beam-splitting collimating concave mirror is made spherical with a radius of the reflecting surface R ₀ , inclined at an angle

₀ to the central axis, while the optical forces, tilt angles and the displacement of the components satisfy the conditions:

Where

- equivalent optical power of the helmet-mounted wide-angle collimator display optical system. 2. A helmet-mounted wide-angle collimator display optical system according to claim 1, characterized in that a polarizing beam splitting prism is installed between the liquid crystal display and the projector, reflecting one of the polarizations of the radiation and transmitting the other, and an LED lighting collimator.

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