RU2848686C1 - Device (variations) for displaying augmented reality, method (variations) of operation of aforementioned device, augmented reality glasses (variations) based on aforementioned device - Google Patents

Abstract

FIELD: information technology.

SUBSTANCE: invention relates to waveguide-based augmented reality devices. The augmented reality display device comprises: a projector, an optical combiner comprising a curved waveguide, wherein the crossed DOE comprises a first diffraction sub-lattice and a second diffraction sub-lattice superimposed on each other so that they form a single diffraction structure, wherein the period of the first diffraction sub-lattice is equal to the period of the second diffraction sub-lattice, wherein the projector is designed to project beams onto the crossed DOE.

EFFECT: reduction of distortion and improvement of virtual image quality.

64 cl, 21 dwg

Description

Field of technology

The present invention relates to augmented reality devices, including augmented reality glasses and augmented reality helmets.

Description of the prior art

Interest is growing in augmented reality (AR) devices such as HMDs (head-mounted displays) or HUDs (head-up displays) designed for specific applications and offering high image quality. Planar (flat) waveguides, which have diffractive optical elements (DOEs) on their surface for input, conversion, and output of optical radiation, are the most widely used combiners. A planar waveguide is a transparent plate made of optical material with two plane-parallel surfaces. A beam of parallel rays within such a waveguide can propagate without distortion over any distance. Augmented reality devices with such combiners are lightweight, small in size, and inexpensive, can provide a wide field of view, and have high light transmittance (i.e., high transmission of the real image). However, such combiners generate a virtual image not only from the side where the user's eye is located but also from the side opposite the user. This may result in an external observer, from a certain position, being able to see partially or completely the virtual image being generated for the user, just like the user, which may be undesirable. Furthermore, the use of a flat optical combiner is not always feasible, as, for example, car windshields, motorcycle helmet lenses, sports glasses, or eyeglass lenses are cylindrical or spherical.

To solve these problems, a curved waveguide can be used as an optical combiner. For example, in a motorcycle helmet or augmented reality glasses, such a combiner would curve around the user's head, making it more compact and comfortable. A device with such a combiner would be more ergonomic and aesthetically pleasing, while the virtual image would be clearly and distinctly visible only to the user; for an outside observer, the beams would be out of focus, resulting in a distorted and indistinguishable image.

An important characteristic of such devices is the field of view (FOV)—the angular space in which virtual images are observed, complementing the user's real environment. The field of view can vary horizontally and vertically. Two-dimensional pupil dilation of the optical system (horizontally and vertically) provides a large field of view (FOV) and a large eye movement field (EMB) in both directions. Solutions for two-dimensional pupil dilation for planar waveguides are well known in the art.

The use of a curved waveguide as a combiner is associated with significant difficulties in converting and transmitting optical radiation through it.

For example, consider the case of a parallel beam of rays incident on a curved waveguide, which is a concentric cylindrical meniscus. Let's say this beam is introduced into the waveguide using an input diffractive element with a constant period. The beam of parallel rays incident on the waveguide will transform inside the waveguide into a non-parallel beam, whose rays will propagate within the waveguide at different angles. This effect must be taken into account when designing augmented reality glasses with a curved combiner.

When using either flat or curved waveguides with one input and one output DOE, the user has a limited field of view in the direction perpendicular to the transmission direction. Increasing the field of view in two directions in prior art devices is achieved by using additional diffractive optical elements, called multipliers, or by increasing the projector pupil size, or by using multiple projectors. Using additional or larger projectors increases the device's dimensions.

Document WO 2020/232170 A1 (published November 19, 2020) is known in the prior art. This document discloses an optical imager that includes a curved waveguide body supplemented with holographic layers positioned on the surface of the waveguide body to transmit light into the waveguide body and redirect it as needed. At least one of the holographic layers is configured to function as a lens element with a non-zero optical power. A disadvantage of this known device is the small field of view of the optical system and poor image quality.

Prior art includes document US 11385465 B2 (published July 16, 2020), which discloses a curved waveguide that can be used as an optical imaging unit or as part of an optical imaging unit for a HMD. The waveguide is positioned in front of at least one eye and has a concave shape when viewed from the eye. The waveguide comprises: a rear surface facing the eye; and a front surface facing away from the eye. Light is directed through the waveguide, reflecting on one or both of the front surface and the rear surface. The waveguide includes a diverging structure whose absolute focal length is less than or equal to the radius of curvature of the waveguide. A disadvantage of this prior art device is the inability to two-dimensionally dilate the pupil of the optical system.

Document US 9733475 B1 (published August 15, 2017) discloses a head-up display (HUD) or head-up display (HMD). The display includes a cylindrical, elliptical, or curved optical combiner that can be used with a projector providing pre-aberrated light. A drawback of this known device is the inability to perform two-dimensional pupil dilation of the optical system.

Document GB 2608908 A (published January 18, 2023) is known in the prior art, and discloses an optical system that includes a waveguide, input optics, and an image source. The waveguide can be cylindrical, and the first and second opposing surfaces of the waveguide can be concentric opposing surfaces defining a common axis of the cylinder. Another drawback of this known device is the inability to two-dimensionally dilate the pupil of the optical system.

The prior art also includes the Orion augmented reality glasses device (“The evolution of display materials and processes for full augmented reality”, Nihar Mohanty, Conference Optical Architectures for Displays and Sensing in Augmented, Virtual, and Mixed Reality (AR, VR, MR) VI, published 01/27/2025 https://www.spiedigitallibrary.org/conference-proceedings-of-spie/PC13414/PC1341409/The-evolution-of-display-materials-and-processes-for-full-augmented/10.1117/12.3041338.short), in which flat waveguides are used as optical combiners for the left and right eyes, which form a virtual image with a diagonal field of view of about 70°. A large field of view is achieved thanks to the high refractive index of the waveguide material, which is silicon carbide (SiC), with a refractive index of n=2.6 and is very expensive. However, a parasitic virtual image still forms on the outside of the optical combiner and can be observed by an unauthorized person. Furthermore, the high cost of the product and the difficulty of manufacturing waveguides from this material have delayed its market entry.

Thus, existing devices and methods cannot simultaneously offer the achievement of the required characteristics of an augmented reality device: the curved configuration of the combiner and the two-dimensional pupil dilation of the optical system.

The technical problem solved by the present invention is the need to overcome the disadvantages inherent in the above devices by creating an augmented reality device with a curved combiner that forms a high-quality virtual image with the pupil of the optical system dilated in two directions.

The essence of the invention

A device for displaying augmented reality is proposed, containing:

- a projector that forms the original image;

- an optical combiner, which is a curved waveguide in the form of a concentric cylindrical or concentric spherical meniscus, containing a crossed diffractive optical element (DOE) and an output DOE;

wherein the crossed DOE consists of a first diffraction subgrating and a second diffraction subgrating superimposed on each other so that they represent a single diffraction structure,

where the period of the first diffraction subgrating is equal to the period of the second diffraction subgrating,

wherein the projector is designed with the ability to project rays forming the original image onto the crossed DOE in such a way that the rays emanating from one point of the original image fall at the same angle relative to the normal to the surface of the curved waveguide at the points of incidence,

wherein the vector of the first diffraction subgrating and the vector of the second diffraction subgrating in the coordinate system associated with the normal to the surface of the curved waveguide at each point of the DOE have equal length and are rotated relative to each other by an angle of 120°,

wherein the crossed DOE is designed with the possibility of:

- input of radiation from the projector into a curved waveguide,

- radiation propagation inside a curved waveguide,

wherein the curved waveguide is configured to propagate the rays of the original image from the input diffractive optical element to the output diffractive optical element by means of total internal reflection from the surfaces of the curved waveguide,

Moreover, the output DOE has a variable period, due to which a virtual image is formed from the side of the concave surface of the curved waveguide.

A method for operating a device for displaying augmented reality is also proposed, comprising the steps of:

form the original image using a projector;

the rays of the original image are introduced into the curved waveguide by means of one of the first or second diffraction subgratings of the crossed diffractive optical element (DOE);

injected rays:

propagate inside a curved waveguide at angles of total internal reflection,

fall again onto the crossed DOE,

undergo diffraction on one of the second or first diffraction subgratings,

propagate inside the curved waveguide at angles of total internal reflection, without interacting with the crossed DOE, fall on the output DOE, and, undergoing diffraction, are removed from the waveguide, forming a virtual image.

A device for displaying augmented reality is also proposed, containing

- a projector that forms the original image;

- an optical combiner, which is a curved waveguide in the form of a concentric cylindrical or concentric spherical meniscus, containing an input diffractive optical element (DOE), a crossed DOE and an output DOE;

wherein the input DOE is designed with the possibility of introducing radiation from the projector into the waveguide and has a constant period;

where the vector of the input DOE in the coordinate system associated with the normal to the surface of the curved waveguide is the same at each point of the input DOE;

wherein the crossed DOE consists of a first diffraction subgrating and a second diffraction subgrating superimposed on each other so that they represent a single diffraction structure,

wherein the strokes of the first diffraction subgrating and the second diffraction subgrating are located symmetrically relative to the direction of transmission of the field of view along the curved waveguide,

where the period of the first diffraction subgrating is equal to the period of the second diffraction subgrating;

wherein the crossed DOE is designed with the possibility of multiplying radiation inside the curved waveguide;

wherein the curved waveguide is configured to propagate the rays of the original image from the input diffractive optical element to the output diffractive optical element by means of total internal reflection from the surfaces of the curved waveguide;

Moreover, the output DOE has a variable period, due to which a virtual image is formed from the side of the concave surface of the curved waveguide.

A method for operating a device for displaying augmented reality is also proposed, comprising the steps of:

form the original image using a projector;

the rays of the original image are introduced into a curved waveguide by means of an input diffractive optical element (DOE),

injected rays:

hit the crossed DOE, undergo diffraction on one of the first or second diffraction subgratings of the crossed DOE, propagate further at angles of total internal reflection inside the curved waveguide, and undergo diffraction again on one of the second or first diffraction subgratings of the crossed DOE;

propagate inside the curved waveguide at angles of total internal reflection, without interacting with the crossed DOE, fall on the output DOE, and, undergoing diffraction, are removed from the waveguide, forming a virtual image.

A device for displaying augmented reality is also proposed, containing

- a projector that forms the original image;

- an optical combiner, which is a curved waveguide having the shape of a concentric cylindrical or concentric spherical meniscus, containing a crossed diffractive optical element (DOE), a first multiplying DOE, a second multiplying DOE and an output DOE;

wherein the crossed DOE consists of a first diffraction subgrating and a second diffraction subgrating superimposed on each other so that they represent a single diffraction structure,

where the period of the first diffraction subgrating is equal to the period of the second diffraction subgrating,

wherein the projector is designed with the ability to project rays forming the original image onto the crossed DOE in such a way that the rays emanating from one point of the original image fall at the same angle relative to the normal to the surface of the curved waveguide at the points of incidence,

wherein the vector of the first diffraction subgrating and the vector of the second diffraction subgrating in the coordinate system associated with the normal to the surface of the curved waveguide at each point of the DOE have equal length and are rotated relative to each other by an angle of 120°,

wherein the crossed DOE is designed with the possibility of introducing radiation from the projector into the curved waveguide;

wherein the first multiplying DOE has the same structure as the first diffraction subgrating;

wherein the second multiplying DOE has the same structure as the second diffraction subgrating;

wherein the first and second multiplying DOEs are located one above the other relative to the direction of transmission of the field of view, close to each other, wherein the strokes of the first multiplying DOE and the second multiplying DOE have the same period, equal to the period of the diffraction subgratings of the crossed DOE, are symmetrical relative to the plane perpendicular to the axis of the cylindrical surfaces of the waveguide, and have an inclination to this plane equal to 30°;

wherein the crossed DOE is located in the area of the exit pupil of the projector at the junction of the first multiplying DOE and the second multiplying DOE opposite the projector;

wherein the curved waveguide is designed with the possibility of propagating the rays of the original image from the input diffractive optical element to the output diffractive optical element by means of total internal reflection from the surfaces of the curved waveguide, wherein the output DOE has a variable period, due to which a virtual image is formed from the side of the concave surface of the curved waveguide.

A method for operating a device for displaying augmented reality is also proposed, comprising the steps of:

form the original image using a projector;

the rays of the original image are introduced into a curved waveguide by means of a crossed diffractive optical element (DOE),

beams introduced into one of the first or second diffraction subgratings of the crossed DOE:

propagate inside a curved waveguide at angles of total internal reflection;

undergo diffraction at each of the first multiplying DOE and the second multiplying DOE,

propagate inside the curved waveguide at angles of total internal reflection towards the output DOE;

fall on the output DOE and, undergoing diffraction, are removed from the waveguide, forming a virtual image.

Moreover, for each version of the device:

The variable period of the output DOE can be designed such that rays emanating from a single point of the original image, passing through a curved waveguide and incident on the output DOE are transformed into parallel beams of rays. The DOEs can be arranged on the curved waveguide one after another transversely to the axis of the concentric cylindrical meniscus surfaces. The DOEs can be arranged on the curved waveguide one after another along the axis of the concentric cylindrical meniscus surfaces. The variable period of the output DOE can be designed such that rays emanating from a single point of the original image, passing through a curved waveguide and incident on the output DOE are transformed into diverging beams of rays. The DOEs can be arranged on the curved waveguide one after another transversely to the axis of the concentric cylindrical meniscus surfaces. The DOEs can be arranged on the curved waveguide one after another along the axis of the concentric cylindrical meniscus surfaces. Moreover, the period of the output DOE at the point corresponding to the center of the eye movement field can be equal to the period of the subgratings of the crossed DOE. All DOEs can be positioned symmetrically to the axis in the direction of the visual field translation. The output DOE can be designed such that the diffraction efficiency of the output DOE in the region located closer to the crossed DOE is lower than in the region located further from the crossed DOE.

If the curved waveguide has the shape of a concentric cylindrical meniscus, the DOEs are located on the curved waveguide one after the other across the axis of the surfaces of the concentric cylindrical meniscus, the rays emerging from one point of the original image, passing through the curved waveguide and falling on the output DOE, are transformed into parallel beams of rays, the period output DOE at each point with coordinates equals:

Where

- offset and rotation angle to transition to a rotated coordinate system,

- the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system,

- the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system,

- wavelength of the original image beam,

- the angle between the center of the input and output DOEs,

- period of introductory DOE.

If the curved waveguide has the shape of a concentric spherical meniscus, the DOEs are located on the curved waveguide one after the other across the axis of the surfaces of the concentric cylindrical meniscus, the rays emerging from one point of the original image, passing through the curved waveguide and falling on the output DOE, are transformed into parallel beams of rays, the period output DOE at each point with coordinates equals:

Where

Where

rotation angles for transition to a rotated coordinate system,

- the component of the grid vector of the output DOE in the direction of the X-axis in the rotated coordinate system,

- the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system,

- wavelength of the original image,

- the angle between the center of the input and output DOEs,

- the period of the sublattices of the crossed DOE.

If the curved waveguide has the shape of a concentric cylindrical meniscus, the DOEs are located on the curved waveguide one after the other across the axis of the surfaces of the concentric cylindrical meniscus, the rays emerging from one point of the original image, passing through the curved waveguide and falling on the output DOE, are transformed into diverging beams of rays, the period output DOE at each point with coordinates equals:

Where

Where

- offset and rotation angle to transition to a rotated coordinate system,

- the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system,

- is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image,

- normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation,

- the angle between the center of the input and output DOEs,

- radius of curvature of the concave surface of the waveguide,

- period of introductory DOE.

If the curved waveguide has the shape of a concentric spherical meniscus, the DOEs are located on the curved waveguide one after the other across the axis of the surfaces of the concentric cylindrical meniscus, the rays emerging from one point of the original image, passing through the curved waveguide and falling on the output DOE, are transformed into diverging beams of rays, the period output DOE at each point with coordinates equals:

Where

Where - rotation angles for transition to a rotated coordinate system,

- the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image,

- normalizing coefficient of the beam vector at the output of the output DOE,

- wavelength of radiation,

- the angle between the center of the input and output DOEs,

- radius of curvature of the concave surface of the waveguide,

- period of introductory DOE.

If the curved waveguide has the shape of a concentric spherical meniscus, an additional optical compensator may be used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a spherical negative lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. If the curved waveguide has the shape of a concentric cylindrical meniscus, an additional optical compensator may be used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a cylindrical lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. Moreover, the curved waveguide may have the same thickness and the same curvature, at least in the working region.

Augmented reality glasses are provided, comprising a left-eye element and a right-eye element, wherein each left-eye and right-eye element comprises an augmented reality display device according to any embodiment. Moreover, the curved waveguide contained in the left-eye element and the curved waveguide contained in the right-eye element have the same radius of curvature. Moreover, when the curved waveguide of each element is shaped like a concentric cylindrical meniscus, both curved waveguides share a common axis. Moreover, when the curved waveguide of each element is shaped like a concentric spherical meniscus, both curved waveguides share a common center of curvature.

Brief description of the drawings

The above and other features and advantages of the present invention will become clearer in the following description taken in conjunction with the drawings, which show the following:

Fig. 1A illustrates the propagation of a beam inside a planar waveguide in the plane of beam propagation, Fig. 1B illustrates the propagation of a beam inside a concentric spherical meniscus in the plane of beam propagation, Fig. 1C illustrates an isometric view of the ray path inside a concentric spherical meniscus.

Fig. 2 illustrates a system for specifying coordinates of points on the surface of a waveguide in the form of a concentric spherical meniscus.

Fig. 3 illustrates the trajectory of an arbitrary ray inside a concentric cylindrical meniscus and its projections onto planes in a cylindrical coordinate system.

Fig. 4 illustrates a system for specifying coordinates of points on the surface of a waveguide in the form of a concentric cylindrical meniscus.

Fig. 5 illustrates the symmetrical arrangement of the eye movement field relative to the output DOE.

Fig. 6 illustrates the path of rays inside an optical combiner in the form of a curved waveguide, which is a concentric spherical meniscus, in which a crossed DOE performs the function of an input and multiplying DOE.

Fig. 7 illustrates the path of rays inside an optical combiner in the form of a curved waveguide, which is a concentric cylindrical meniscus, in which a crossed DOE performs the function of an input and multiplying DOE.

Fig. 8 illustrates the path of rays inside an optical combiner in the form of a curved waveguide, which is a concentric cylindrical meniscus, in which the crossed DOE performs the function of only a multiplying DOE.

Fig. 9 illustrates the design of an optical combiner in the form of a curved waveguide for an embodiment in which the crossed DOE performs the function of an input DOE, the first multiplying DOE and the second multiplying DOE act as the multiplying DOE, and the surface of the curved waveguide is turned into the plane of the drawing.

Fig. 10A illustrates the arrangement of the DOE on the inner surface of the concentric spherical meniscus for an embodiment comprising a crossed DOE and a lead-out DOE; 10B illustrates the arrangement of the DOE on the inner surface of the concentric spherical meniscus for an embodiment comprising an input DOE, a crossed DOE, and a lead-out DOE; 10C illustrates the arrangement of the DOE on the inner surface of the concentric spherical meniscus for an embodiment comprising a crossed DOE, a first multiplying DOE, a second multiplying DOE, and a lead-out DOE.

Fig. 11A illustrates the arrangement of the DOE across the axis of the concentric cylindrical meniscus for an embodiment comprising a crossed DOE, a lead-out DOE; 11B illustrates the arrangement of the DOE across the axis of the concentric cylindrical meniscus for an embodiment comprising an inlet DOE, a crossed DOE, a lead-out DOE; 11C illustrates the arrangement of the DOE across the axis of the concentric cylindrical meniscus for an embodiment comprising a crossed DOE, a first multiplying DOE, a second multiplying DOE, a lead-out DOE; 11D illustrates the arrangement of the DOE along the axis of the concentric cylindrical meniscus for an embodiment comprising a crossed DOE, a lead-out DOE; 11E illustrates the arrangement of the DOE along the axis of the concentric cylindrical meniscus for an embodiment comprising an inlet DOE, a crossed DOE, a lead-out DOE; 11F illustrates the arrangement of the DOE along the axis of the concentric cylindrical meniscus for an embodiment comprising a crossed DOE, a first multiplying DOE, a second multiplying DOE, and a lead DOE.

Fig. 12 illustrates the design of augmented reality glasses.

Detailed description of the invention

A curved waveguide-based optical combiner for displaying augmented reality, as well as augmented reality glasses based on said optical combiner, are proposed. The proposed invention provides a wide field of view for the user, with an increased field of view both horizontally and vertically. The proposed invention provides improved virtual image quality, which is maintained over a wide range of the user's eye position relative to the optical combiner, as well as high virtual image brightness and uniform brightness distribution throughout the virtual image.

The following terms are used in describing the proposed invention:

A virtual image is a virtual image obtained by extending rays that do not converge in image space (from the user's perspective). The key to using a virtual image in augmented reality devices is that it must be virtual, otherwise the user will not see it.

An optical combiner is an optical device that creates a virtual image in front of the user that complements the user's real environment without interfering with the user's ability to observe the surrounding real environment.

The field of view (FOV) of an optical system (angular field) is the angular range within which the user can observe the virtual image formed by the optical combiner. The center of the FOV corresponds to the center of the virtual image, and the edge of the FOV corresponds to the edge of the maximum possible size of the virtual image.

The eye motion box (EMB) is the area within which the eye, while moving, can view the entire field of view generated by an augmented reality device without loss and with a given quality. The eye motion box is a linear region in space within which the eye observes the entire field of view, meaning rays from any point in the virtual image enter the pupil of the eye. Outside this region, part of the field of view is partially or completely lost; i.e., outside this region, rays from all or some part of the virtual image do not enter the entrance pupil of the eye. The user's eye constantly moves and rotates, and the augmented reality device on the user's head may also shift slightly, and the pupil of the eye will constantly change its position relative to the augmented reality device. The eye motion box of the augmented reality device's optical combiner must correspond to the range of possible eye movement of the user.

The exit pupil (or pupil of an optical system) is the paraxial image of the aperture diaphragm in image space, formed by the subsequent part of the optical system along the forward ray path. The fundamental property of the exit pupil is that at any point within it, rays exist that form the entire field of view. Waveguide optics offers technical solutions for multiplying the exit pupil, that is, increasing its size without increasing the optical system's dimensions in the direction of the optical axis. Classic optics allow for increasing the exit pupil size, but this significantly increases the optical system's dimensions. Waveguide optics, through multiple reflections of ray beams within the waveguide, allows this to be achieved without increasing the optical system's dimensions in the direction of the optical axis.

Collimated light (or collimated beam) is defined as light whose rays are parallel or have a slight divergence.

A concentric spherical meniscus is an optical component formed by two spherical surfaces whose centers of curvature are located at the same point.

A concentric cylindrical meniscus is an optical component formed by two cylindrical surfaces whose axes coincide. This curved waveguide has an inner (concave) surface facing the user's eye and an outer (convex) surface facing away from the user's eye and toward the external world.

Optical axis is the axis (line) on which the centers of curvature of the optical components of an optical system lie.

Diffraction grating vector - is a vector at a selected point on the surface of the diffraction grating, equal in magnitude to , Where - is the period of the diffraction grating, and lies in the plane perpendicular to the surface normal at the selected point, and perpendicular to the direction of the diffraction grating lines at the selected point.

Let us consider the propagation of a ray inside a planar waveguide 1, the surfaces of which are parallel (Fig. 1A). The trajectory of any ray propagating at angles of total internal reflection inside the planar waveguide 1 will lie in the same plane. This follows from the fact that the normals at any point on the surfaces of the planar waveguide 1 for both sides will be parallel to each other and from the law of reflection (the equality of the angles of incidence and reflection, and the incident ray, the reflected ray, and the normal at the point of incidence lie in the same plane). The angles of incidence of any ray propagating inside the planar waveguide at angles of total internal reflection relative to the normal at the point of incidence on both surfaces of the waveguide will be equal, i.e. β1=β2=β3=β4=β5=β6=β7=β8

Let us consider the propagation of a ray inside a waveguide in the form of a concentric spherical meniscus 2 with an inner radius of curvature R1 and an outer radius of curvature R2. Fig. 1B illustrates the ray trajectory inside the concentric spherical meniscus 2 (a curved waveguide) in the plane of its propagation; for clarity, Fig. 1C shows an isometric view of the ray trajectory inside a curved waveguide in the form of a concentric spherical meniscus 2. The trajectory of any ray propagating at TIR angles inside such a waveguide will, as in the case shown in Fig. 1A, lie in the same plane. This follows from the fact that the normals at any point on the surface of the waveguide in the form of a concentric spherical meniscus 2 for both of its surfaces intersect at one point (at the center of curvature of the surfaces of the curved waveguide) and from the law of reflection. The angles of incidence of any ray relative to the normal at the point of incidence on the convex (external) surface of the curved waveguide 2 will be equal and will be repeated with each reflection, and on the concave (internal) surface of the curved waveguide they will also be equal and will be repeated with each reflection, i.e. β1=β2=β5=β6 … and β3=β4=β7=β8 ….

Let us adopt the following system of specifying coordinates of points on the surface of a curved waveguide in the form of a concentric spherical meniscus 2, shown for clarity in Fig. 2. Let us select as the starting point a point C on the inner surface of the concentric spherical meniscus 2, as shown in Fig. 2. Let us adopt the initial rectangular coordinate system XcYcZcO1, such that the origin of coordinates O1 lies in the center of the spherical surfaces of the concentric spherical meniscus 2, the Zc axis passes through point C, the Yc axis is plotted in the vertical plane, and the Xc axis complements the XcYcZcO1 coordinate system to the right.

Let us define the coordinates of an arbitrary point D through two rotations, the first rotation around the Xc axis, the second rotation around the Yc axis. Obtained from the XcYcZcO1 coordinate system through rotations the coordinate system XDYDZDO1 will be such that the origin point O1 coincides with the center of curvature of the spherical surfaces of the concentric spherical meniscus 2, and the ZD axis passes through point D.

In order to transmit beams of rays that form a virtual image without distortion through a waveguide in the form of a concentric spherical meniscus, it is necessary that the rays incident at point C and at point D, and forming the same element of the virtual image, have coordinates of the wave vector of the ray incident at point C in the XcYcZcО1 coordinate system equal to the coordinates of the wave vector of the ray incident at point D in the XDYDZDO1 coordinate system.

Let us consider the propagation of an arbitrary ray inside a concentric cylindrical meniscus 3 (a curved waveguide) with an internal radius of curvature R1 and an external radius of curvature R2. The curved waveguide is shown in isometry in Fig. 3. The path of an arbitrary ray in the cylindrical concentric meniscus 3 and its projections onto planes in a cylindrical coordinate system are also shown.

In the general case, as shown in Fig. 3, the trajectory of a ray propagating at angles of total internal reflection inside the cylindrical concentric meniscus 3 will lie in a set of non-parallel planes O2A1A3, O3A2A4, O4A3A5, O5A4A6, etc., in which the incident and reflected rays and the normal at the corresponding point of incidence lie (for example, the incident ray A1A2, the reflected ray A2A3 and the normal A2O2 for the point of incidence A2 lie in the plane O2A1A3, etc.), as shown in Fig. 3, except for two exceptions.

The first exception is when the plane formed by the incident ray and the normal at the point of incidence lies along the axis of the cylindrical surfaces of the waveguide. In this case, the ray path, as in the case of a planar waveguide (Fig. 1A), will lie in the same plane, and the angles of incidence for each re-reflection will be the same for the convex and concave surfaces of the curved waveguide.

The second exception is when the plane formed by the incident ray and the normal at the point of incidence is perpendicular to the axis of the cylindrical surfaces of the waveguide. In this case, the ray path, as in the case of a waveguide in the form of a spherical concentric meniscus (Fig. 1B), will lie in the same plane, and the angles of incidence of the ray upon re-reflection from the outer (convex) surface of the waveguide will be equal to each other, and upon re-reflection from the inner (concave) surface of the waveguide, they will be equal to each other.

As shown in Fig. 3 in projection along the axis of the cylindrical surfaces of the concentric cylindrical meniscus, that is, when projecting the ray trajectory onto a plane perpendicular to the axis of the cylindrical surfaces of the waveguide - A1''A2'', A2''A3'', A3''A4'', A4''A5'', A5''A6'', the ray trajectory is similar to the ray trajectory for a concentric spherical meniscus (Fig. 1B, 1C). It can be shown that for the concentric cylindrical meniscus 3, as in the case of the concentric spherical meniscus 2, the angles of incidence of any ray relative to the normal at the point of incidence on the convex surface of the waveguide will be equal and will be repeated with each re-reflection, and on the concave surface of the waveguide they will also be equal and will be repeated with each re-reflection, i.e. (see Fig. 3) β1=β2=β5=β6 … and β3=β4=β7=β8….

Let us adopt the following system of specifying coordinates of points on the surface of a waveguide in the form of a cylindrical concentric meniscus 3, shown for clarity in Fig. 4. Let us select as the starting point a point C on the inner surface of the cylindrical concentric meniscus 3, as shown in Fig. 4. Let us adopt the initial rectangular coordinate system XcYcZсО1, such that the origin of coordinates О1 lies on the axis of the cylindrical surfaces of the cylindrical concentric meniscus 3, the Zc axis passes through point C and coincides with the normal to the surface of the waveguide at point C, the Yc axis is plotted along the axis of the cylindrical surfaces of the waveguide, and the Xc axis complements the coordinate system XcYcZcО1 to the right.

Let us define the coordinates of an arbitrary point D through rotation around the Yc-axis and the y-shift along the Yc-axis. Obtained from the XcYcZcO1 coordinate system through the shift and rotation the coordinate system XDYDZDO2 will be such that the origin point O2 lies on the axis of the cylindrical surfaces of the cylindrical concentric meniscus 3, and the axis ZD passes through point D and coincides with the normal to the surface of the cylindrical concentric meniscus 3 at point D.

In order to transmit through a waveguide in the form of a concentric cylindrical meniscus 3 (concentric spherical meniscus 2), beams of rays that form a virtual image without distortion, it is necessary that the rays that form the same element of the virtual image, propagating inside the waveguide and falling at point C and at point D, have coordinates of the wave vector of the ray falling at point C in the coordinate system XcYcZcО1, equal to the coordinates of the wave vector of the ray falling at point D in the coordinate system XDYDZDО2 (XDYDZDО1).

Optical combiners of cylindrical or spherical shape, according to the proposed invention, are created taking into account the above-described properties of rays propagating inside a curved waveguide in the form of a concentric spherical meniscus 2 or a concentric cylindrical meniscus 3, while when calculating the parameters of the DOE, the following conditions must be taken into account and met:

1) rays emitted from one point of the projected image must enter the waveguide at the same angles relative to the normal at each point of incidence; in this case, a one-to-one correspondence between the rays propagating inside the waveguide and the points of the virtual image is achieved.

2) the rays that form the entire field of view must be redistributed within the waveguide in such a way as to ensure uniform brightness of all elements of the virtual image at all points in the eye movement fields,

3) the rays emerging from the waveguide, corresponding to each point of the projected image, must emerge as parallel or diverging beams, forming a virtual image at infinity (if parallel) or at a finite distance (if diverging).

For this purpose, an optical combiner is proposed. This combiner is a curved waveguide shaped like a concentric cylindrical meniscus 2 or a concentric spherical meniscus 3, on which diffractive optical elements (DOEs) are positioned. It is possible to use volumetric phase holographic optical elements (HOEs) or surface relief DOEs. DOEs can be deposited on the waveguide using any suitable method. The following technologies for producing DOEs on waveguides are the most widely used:

- recording of volumetric phase holographic elements HOE on a film of the Bayfol Covectro type and lamination of this film onto a waveguide;

- photo nanoimprint lithography of surface relief DOEs, when a layer of UV-curable photopolymer is applied to the waveguide, a matrix with an imprint of the DOE with the desired profile is pressed against the waveguide, and the polymer is cured by exposing it to UV radiation;

- formation of the DOE relief directly on the surface of the waveguide material, for example, using ion-plasma etching or thermoplastic molding for plastics.

The curved waveguide may be made of any suitable material, such as glass or plastic, such as polymethyl methacrylate (PMMA), which has a refractive index of n=1.5 and provides a field of view (FOV) of 30°, or any other suitable materials.

DOEs located on a curved waveguide are:

A) A crossed DOE, which functions as an input and multiplying diffractive element, is a single diffractive structure consisting of two superimposed diffraction subgratings: the first subgrating and the second subgrating. The periods of the subgratings are identical and equal to T0. The period T0 is selected such that rays incident from the projector on the DOE, within an angular range corresponding to the projector's field of view, are diffracted into the curved waveguide within the range of angles of total internal reflection of the rays within the curved waveguide. That is, the parameters of the crossed DOE are selected in accordance with the geometry of the curved waveguide such that the first condition mentioned above is met. In this case, the crossed DOE functions as an input DOE, transforming rays from the projector into rays propagating within the curved waveguide while maintaining a one-to-one correspondence between these rays.

The lines of the subgratings are arranged symmetrically relative to the direction of transmission of the field of view, and the angle between the direction of transmission of the field of view and the lines of the first and second subgratings is 30 ⁰ .

A projector is generally a radiation source with an optical system. The projector's optical system constructs an image of the radiation source at some distance from the projector, typically at infinity. The radiation source (projector), which forms the original image, can be broken down into point radiation sources, which the projector's optical system transports some distance away from a curved waveguide.

After the beam from the projector enters the curved waveguide through the crossed DOE, it propagates within the curved waveguide at TIR angles, re-incides with the crossed DOE, undergoes further diffraction, and is redirected toward the output DOE. This sequence of beam propagation within the curved waveguide ensures pupil multiplication in a direction perpendicular to the direction of field of view transfer with high uniformity, thereby fulfilling the second condition for creating an optical combiner, described above.

The first and second subarrays may be elements of a single crossed DOE, i.e., they may be formed as a single unit, such as the diamond-shaped structure disclosed in WO 2008081070 A1 (publication date July 10, 2008). To increase the efficiency of the optical combiner, it is possible to manufacture a crossed DOE, as disclosed, for example, in US 10061124 B2 (publication date August 28, 2018), or by any other suitable means.

The crossed DOE is located on the inner (opposite the user's eye) surface of the waveguide.

B) An output DOE, which is located downstream of the crossed DOE along the ray path. A description of the structure of the output DOE with a variable period used in the present invention for a waveguide in the form of a concentric cylindrical meniscus is disclosed in document RU 2801055 C1 (publication date 01.08.2023). The output DOE has a variable period such that the virtual image on the user's retina is formed by converting rays corresponding to a single point of the original image, passing through the curved waveguide and incident on the output diffractive optical element, into parallel (or diverging) beams of rays. This fulfills the third condition for creating an optical combiner, described above. For a curved waveguide, the output DOE must have a variable period and conform to a specific period variation law.

The variable period of the output DOE solves the problem of forming the correct beam structure during radiation extraction. When radiation is extracted from the waveguide by diffraction on the output diffractive optical element, the variable period allows rays corresponding to a single point in the original image to emerge from the curved waveguide toward the user's eye, parallel to each other for a single image element, or diverging from a single point for a single image element. All points must lie in the same plane—the virtual image plane. Thus, the output of the curved optical combiner is a virtual image free of aberrations and distortions such as ghosting.

Fig. 5 shows a section of a curved waveguide (this can be either a concentric spherical meniscus or a concentric cylindrical meniscus) with a radius of curvature of the inner surface of the waveguide R1 and a center of curvature at point O1. To minimize aberrations, it is necessary that the period of the crossed DOE 4 be equal to the period in the central part Cout of the output DOE 5, then the eye movement field 5a (Ceb is the center of the eye movement field) will be located symmetrically relative to the output DOE 5, as shown in Fig. 5. In this case, the beam (designation of the wave vector of the beam) incident normally on the input DOE at its center Cin, will correspond to the same point of the original image as the beam , emerging at the center Cout of the output DOE 5, as shown in Fig. 5. In this case, the center of the eye movement field 5a Ceb, the center Cout of the output DOE 5, and the center of curvature of the waveguide O1 will lie on the same straight line, corresponding to the normal to the inner surface of the curved waveguide at point Cout. The period at the remaining points of the output DOE 5 should be such as to form a parallel (or diverging) beam of rays for the rays corresponding to each point of the original image.

Figure 6 illustrates the trajectory of a beam propagating inside a curved waveguide in the form of a concentric spherical meniscus 2 with a crossed DOE 4 and an output DOE 5. As shown in Fig. 6, for example, the beam incident from the center of the projector's exit pupil onto a curved waveguide along the normal O1Cin at point Cin. At point Cin, the incident beam's energy is split into two components, forming two beams. The first beam is formed due to diffraction of the incident beam. on the first subarray of the crossed DOE 4, is introduced into the curved waveguide 2, is reflected from the outer surface of the curved waveguide 2, falls at point D1, undergoes diffraction on the second subarray of the crossed DOE 4, after which, having been repeatedly reflected from the surfaces of the curved waveguide 2, reaches point D2, diffracts at this point on the output DOE 5 and is output from the curved waveguide 2, forming a beam , as shown in Fig. 6. The second beam is formed due to diffraction of the incident beam on the second subarray of the input and multiplying DOE, is introduced into the curved waveguide 2, is reflected from the outer surface of the waveguide, falls at point D3, undergoes diffraction on the first subarray of the crossed DOE 4, after which, having been repeatedly reflected, reaches point D4, diffracts at this point with the output DOE 5 and is removed from the waveguide, forming a beam , as shown in Fig. 6. The rays formed by the ray falling on the crossed DOE 4 along the normal, after multiplication at points D1 and D3, will propagate in planes intersecting along the line O1C1.

In order to form a parallel beam of rays from one point of the original image when outputting a ray at any point of the output DOE 5 vector,rays must coincide with the vectorin the center of the Cout of the output DOE 5, that is, they should be equal to it and have the same direction. For this periodoutput DOE 5 at each point with coordinates, in the rotated coordinate system according to Fig. 2, must correspond to the following expressions:

Where - rotation angles for transition to the rotated coordinate system according to Fig. 2, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image beam, - the angle between the center of the input and output DOEs, - period of introductory DOE.

Fig. 7 shows the trajectory of a beam propagating inside a curved waveguide in the form of a concentric cylindrical meniscus 3. The trajectory of the beam in this case will be similar to the trajectory of the beam for the case of a spherical concentric meniscus, with the difference that after diffraction on the multiplying DOE, the rays formed by the beam incident on the input DOE along the normal propagate in parallel planes D1D2O2, D3D4O3.

As described in document RU 2801055 C1 (publication date 01.08.2023), in the case of a curved waveguide in the form of a concentric cylindrical meniscus, in order to form a virtual image at infinity, the period of the output DOE must be variable.

Period The output DOE 5, located on a concentric cylindrical meniscus, transforming rays emanating from one point of the original image into parallel beams of rays, in the case of image transfer in a direction perpendicular to the common axis of the cylindrical surfaces of the waveguide can be described as follows:

Where - displacement and rotation angle for transition to the rotated coordinate system according to Fig. 4, - the component of the diffraction grating vector of the output DOE in the direction of the x-axis in the rotated coordinate system,- the component of the diffraction grating vector of the output DOE in the direction of the y-axis in the rotated coordinate system,- wavelength of the original image beam,- the angle between the center of the input and output DOEs,- period of introductory DOE.

The strokes of the output DOE for forming a virtual image at infinity must be parallel to the common axis of the cylindrical surfaces of the curved waveguide, since for any coordinates the component of the diffraction grating vector in the direction of the Y axis is equal to 0.

The upper and lower portions of the field of view, both for the concentric cylindrical meniscus and the concentric spherical meniscus, are equal in brightness due to the symmetrical arrangement of all DOEs relative to the field of view transfer direction CinCout (in Figures 6 and 7). Brightness equalization of the virtual image in the horizontal direction can be achieved by varying the diffraction efficiency of the output DOE in the field of view transfer direction in all embodiments of the proposed invention. To achieve this, the output DOE is designed such that the diffraction efficiency of the output DOE is lower in the region located closer to the crossed DOE than in the region located further from the crossed DOE. This allows for highly uniform virtual image brightness without modulating the diffraction efficiency of the crossed DOE.

To satisfy condition 1) mentioned above, the projector's optical system for a waveguide in the form of a concentric cylindrical meniscus must transfer the original image to the axis of the waveguide's cylindrical surfaces in a cross-section perpendicular to this axis (sagittal cross-section) and to infinity in a cross-section passing through the axis of the waveguide's cylindrical surfaces (meridional cross-section). When using a projector with an optical system that forms an image at infinity, this problem can be solved by using an input optical compensator, which is a cylindrical lens located between the projector and the waveguide, as described in RU 2801055 C1 (publication date 01.08.2023).

To satisfy condition 1) mentioned above, for a waveguide shaped like a concentric spherical meniscus, the projector's optical system must transfer the original image to a plane passing through the center of the waveguide's surfaces. In this case, the compensator lens for the projector, with an optical system that forms an image at infinity, must be a spherical negative lens with a focal length equal to the radius of curvature of the waveguide's inner surface.

As shown in Fig. 8, in one embodiment of the proposed invention, the crossed DOE 4 serves only as a multiplying DOE. An input DOE 6, located separately from the crossed DOE 4, is used to couple radiation into the waveguide. That is, the input DOE 6, the crossed DOE 4, which serves as a multiplying DOE, and the output DOE 5 are separately located on the curved waveguide. The input DOE 6 has a constant period T0, and the lines of the diffraction grating of the input DOE 6 must be parallel to the axis of the cylindrical surfaces of the curved waveguide 3. The period and slope of the lines of the crossed DOE 4 can be selected based on the requirements for the optical combiner.

The lines of the first diffraction subgrating and the second diffraction subgrating of the crossed DOE 4 are arranged symmetrically with respect to the direction of field of view transmission along the curved waveguide 3. The period of the first diffraction subgrating is equal to the period of the second diffraction subgrating. The crossed DOE 4 is designed to multiply radiation within the curved waveguide 3. The lines of the crossed DOE 4 must be symmetrical with respect to the plane perpendicular to the axis of the cylindrical surfaces of the curved waveguide 3 .

Fig. 8 shows the path of one beam through a curved waveguide in the form of a cylindrical concentric meniscus 3 with a separate input DOE 6, a crossed DOE 4 and an output DOE 5. Let, for example, the beam is incident from the center O1 of the projector's exit pupil onto curved waveguide 3 along the normal. This beam undergoes diffraction on input DOE 6 at point Cin and is introduced into curved waveguide 3, reflected from the outer surface of curved waveguide 3, and incident at point D1 on crossed DOE 4. At point D1, the energy of the incident beam is split into three components, forming three beams. The first beam at point D1 is formed by the reflection of the beam incident at point D1, which does not interact with crossed DOE 4, will propagate further along curved waveguide 3 at TIR angles to point D6, diffract at point D6 on output DOE 5 and will be output from curved waveguide 3, forming beam . The second beam at point D1 is formed due to the diffraction of the beam incident at point D1 on the first subarray of the crossed multiplying DOE. This beam, having reflected from the outer surface of the waveguide, will again fall on the crossed multiplying DOE at point D2, will diffract at point D2 on the second subarray of the crossed DOE 4, will be repeatedly reflected, will reach point D3, will diffract at this point on the output DOE 5 and will be output from the curved waveguide 3, forming a beam. , as shown in Fig. 8. The third beam at point D1 is formed due to the diffraction of the incident beam on the second subarray of the crossed multiplying DOE, this beam, having reflected from the outer surface of the curved waveguide 3, will again fall on the crossed DOE 4 at point D4, will diffract at point D4 on the first subarray of the crossed DOE 4, will be repeatedly reflected and reach point D5, will diffract at this point on the output DOE 5 and will be output from the curved waveguide 3, forming a beam , as shown in Fig. 8.

A similar ray path will be observed when using a curved waveguide in the form of a concentric spherical meniscus 2.

When using input DOE 6 separately from crossed DOE 4, which functions as a multiplying DOE, the central part of the field of view will appear brighter to the user, meaning that the brightness unevenness of the virtual image will be clearly visible. This is due to the fact that the rays forming the central part of the virtual image will undergo diffraction only twice (at input DOE 6 and at output DOE 5, as the beam in Fig. 8), and the rays that form the peripheral part of the virtual image will undergo diffraction four times (like the rays And in Fig. 8).

In another embodiment of the proposed invention, the input DOE is a crossed DOE 4, the multiplying DOE is a first multiplying DOE 7a and a second multiplying DOE 7b, and the output DOE 5 is used to output the radiation. Fig. 9 illustrates the arrangement and design of the DOE for this embodiment; this figure shows the surface of the waveguide unfolded into the plane of the drawing.

In this embodiment, the crossed DOE 4 has the structure described above.

The first multiplying DOE 7a has the same structure as the first diffraction subgrating of the crossed DOE 4, and the second multiplying DOE 7b has the same structure as the second diffraction subgrating of the crossed DOE 4. The multiplying DOEs 7a and 7b are arranged as shown in Fig. 9, namely, one above the other relative to the direction of transmission of the field of view and close to one another.

The strokes of the first multiplying DOE 7a and the second multiplying DOE 7b have the same period, equal to the period of the crossed DOE 4, are symmetrical with respect to the plane perpendicular to the axis of the cylindrical surfaces of the waveguide, and have an inclination to this plane equal to 30°.

The crossed DOE is located in the area of the exit pupil of the projector (opposite the projector) at the junction of the first multiplying DOE 7a and the second multiplying DOE 7b.

As in the previous embodiments, the output DOE 5 has a variable period, due to which it is designed with the possibility of forming a virtual image on the retina of the user's eye by converting rays emerging from one point of the original image, passing through a curved waveguide and hitting the output diffractive optical element, into parallel or diverging beams of rays.

In this embodiment (Fig. 9), the augmented reality display device will operate as follows. A projector generates an initial image. A crossed diffractive optical element (DOE) introduces the rays of the initial image into a curved waveguide, thereby

The input rays: undergo diffraction on the first sub-array of the crossed DOE 4 and on the second sub-array of the crossed DOE 4, wherein the rays emanating from one point of the original image undergo diffraction on the crossed DOE 4 at the same angle relative to the normal to the surface of the curved waveguide at the point of incidence; are reflected from the outer surface of the curved waveguide, undergo diffraction on the second multiplying DOE 7b and on the first multiplying DOE 7a, are repeatedly reflected by means of total internal reflection from the surfaces of the curved waveguide, and reach the output DOE 5. On the output DOE 5, the rays emanating from one point of the original image are transformed into parallel or diverging beams of rays, forming a virtual image on the retina of the user's eye.

With such an arrangement of the DOE, the brightness of the resulting virtual image will be higher compared to previous embodiments, since during multiplication there will be no losses during input on the first diffraction subgrating of the crossed DOE 4 and diffraction on the first diffraction subgrating of the crossed DOE 4 during multiplication, as well as during input on the second diffraction subgrating of the crossed DOE 4 and diffraction on the second diffraction subgrating of the crossed DOE 4 during multiplication.

In one embodiment of the proposed invention, a virtual image can be formed not only at infinity, but also at a finite distance. This may be useful for people with myopia, or for situations where the user is indoors without a distant background. For this An output DOE 5 is used that will form a virtual image at a finite distance. In this case, the output DOE 5 must form a diverging beam of rays (rather than a parallel one) for each element of the original image from the projector, with the virtual image being constructed in a certain plane located at a finite distance from the user.

For a concentric spherical meniscus, the period output DOE 5, which forms a virtual image at a finite distance , must correspond to the expression

Where

Where - rotation angles for transition to the rotated coordinate system according to Fig. 2, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE.

For a concentric cylindrical meniscus, the structure of the output DOE 5, which forms a virtual image at a finite distance, is described in document RU 2801055 C1 (publication date 01.08.2023), and is also described below. For a concentric cylindrical meniscus, the period output DOE 5, which forms a virtual image at a finite distance , must correspond to the expression:

Where

Where

- offset and rotation angle to transition to a rotated coordinate system,

- the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system,

- is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image,

- normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation,

- the angle between the center of the input and output DOEs,

- radius of curvature of the concave surface of the waveguide,

- period of introductory DOE.

Below are described the options for placing the DOE on a curved waveguide.

For a curved waveguide in the form of a concentric spherical meniscus 2:

Fig. 10A illustrates the arrangement of the DOE on the inner surface of the concentric spherical meniscus 2 for an embodiment containing a crossed DOE 4 and a lead DOE 5;

Fig. 10B illustrates the arrangement of the DOE on the inner surface of the concentric spherical meniscus 2 for an embodiment comprising a separate input DOE 6, a crossed DOE 4 and an output DOE 5;

Fig. 10C illustrates the arrangement of the DOE on the inner surface of the concentric spherical meniscus for an embodiment comprising a crossed DOE 4, a first multiplying DOE 7a, a second multiplying DOE 7b, and a lead DOE 5.

Figures 10A-10C show the eye movement field 5a, with point Ceb marking the center of the eye movement field.

For a curved waveguide in the form of a concentric cylindrical meniscus 3:

Fig. 11A illustrates the arrangement of the DOE across the axis of the concentric cylindrical meniscus 3 for an embodiment containing a crossed DOE 5 performing the function of an input and multiplying DOE and an output DOE 5;

Fig. 11B illustrates the path of rays inside the concentric cylindrical meniscus 3 for an embodiment with the DOE positioned across the axis of the concentric cylindrical meniscus 3 and containing a separate input DOE 6, a crossed DOE 4, which performs the function of a multiplying DOE, and an output DOE 5;

Fig. 11C illustrates the arrangement of the DOE across the axis of the concentric cylindrical meniscus 3 for an embodiment comprising a crossed DOE 4, performing the function of an input DOE, a first multiplying DOE 7a, a second multiplying DOE 7b, an output DOE 5;

Fig. 11D illustrates the arrangement of the DOE along the axis of the concentric cylindrical meniscus 3 for an embodiment containing a crossed DOE 4, which performs the function of an input and multiplying DOE, and an output DOE 5;

Fig. 11E illustrates the arrangement of the DOE along the axis of the concentric cylindrical meniscus 3 for an embodiment containing a separate input DOE 6, a crossed DOE 4 that performs the function of a multiplying DOE, and an output DOE 5;

Fig. 11F illustrates the arrangement of the DOE along the axis of the concentric cylindrical meniscus 3 for an embodiment comprising a crossed DOE 4, which performs the function of an input DOE, a first multiplying DOE 7a, a second multiplying DOE 7b, and an output DOE 5.

Figures 11A-11F show the eye movement field 5a, with point Ceb marking the center of the eye movement field.

It should be noted that in figures 9-11F the DOE strokes are shown conditionally; the DOE periods for visible light are in the range from 300 to 600 nm, and it is impossible to see them on the surface of the waveguide with the naked eye.

The projector is always positioned opposite the DOE, which couples the radiation into the curved waveguide. In Figures 10A-11F, the CinCout arrow indicates the direction of field of view transmission in each configuration.

A curved waveguide can be bent as follows:

only along the direction of transmission of the visual field;

only in the direction perpendicular to the direction of transmission of the field of view;

in any direction by the same radius of curvature.

For the proposed invention to be functional, the curved waveguide in all embodiments must have the same thickness and the same curvature, at least in the working region, which includes the sections where the DOEs are located and the sections between them. If this condition is met, the rays propagating within the curved waveguide maintain their angles relative to the normal to the incident surface. If this condition is not met, the resulting image will exhibit aberrations, as well as distortions such as ghosting, aliasing, and so on. The remainder of the curved waveguide can have any shape.

It should be noted that if the DOE is fabricated not directly on the curved waveguide but from a separate material, the refractive index of the materials from which the curved waveguide and DOE are made affects the field of view of the entire system. The higher the refractive index of both the DOE and the waveguide, the larger the possible field of view (FOV) of the virtual image transferred by the optical combiner. This phenomenon is well known in the prior art; for example, for a curved waveguide, this is described in the paper by EDWARD DEHOOG, JASON HOLMSTEDT, and TIN AYE, "Field of View of Limitations in See-Through HMDs Using Geometric Waveguides," Applied Optics, August 1, 2016.

That is, when designing an optical combiner, specifying a specific field of view size clearly determines the list of materials that can be used.

Augmented reality glasses are similar in design to the HMD helmet, containing an element for the left eye and an element for the right eye, with each of the elements for the left and right eyes being a device for displaying augmented reality in the various versions described above.

Fig. 12 shows one example of a device for augmented reality glasses, in the design of which the devices for displaying augmented reality proposed in the present application are used. When using the proposed technical solutions for a curved waveguide in an HMD or in augmented reality glasses, the optical combiner for the left and right eyes can have a common shape, as shown in Fig. 12. In this case, the field of view for the left eye, formed by the left optical combiner 8a, and the field of view for the right eye, formed by the right optical combiner 8b, will partially intersect with each other or not intersect at all. Then, the projector 9a, forming an image for the left eye, and the projector 9b, forming an image for the right eye, will form source images that are partially or completely (as shown in Fig. 12) not intersecting with each other. An augmented reality display device for the left (right) eye, manufactured according to one of the described embodiments, transfers the original image generated by the left 9a (right 9b) projector into the corresponding eye's field of view. When using such an augmented reality display device, thanks to the human binocular vision system, the user will observe a single virtual image, composed of two separate virtual images generated for the left and right eyes.

Fig. 12 shows an embodiment in which the surfaces of optical combiners 8a and 8b for the left and right eyes have a common center of curvature. In the illustrated example, the center of the eye movement field for the user's left eye and the center of the eye movement field for the user's right eye are separated by 62 mm. The horizontal field of view of each optical combiner is 26°, the distance from the user's eyes to the surface of each optical combiner is 15 mm, and the radius of curvature of the curved waveguides is 150 mm. In this case, the rotation angle of the field of view for each eye relative to the axis of symmetry is 13°. Thus, the virtual image formed for the user's left eye does not intersect with the virtual image formed for the user's right eye, and these virtual images adjoin each other, forming a common virtual image with a horizontal angular size of 52°.

A prototype of a curved PMMA waveguide for augmented reality glasses, manufactured based on the proposed technical solutions, weighs 2.18 g and has a diagonal field of view of 36.2 ^o .

In one embodiment, the augmented reality glasses may comprise a left-eye-only element or a right-eye-only element, wherein the left-eye or right-eye element is a device for displaying augmented reality in the various embodiments described above.

Modeling in the Zemax software package has demonstrated the possibility of creating optical combiners with a curved waveguide, for example, of the following shapes:

- in the form of a concentric cylindrical meniscus with a transfer of the field of view in a plane perpendicular to the axis of the cylindrical surfaces of the waveguide, with the following parameters: operating wavelength 525 nm, field of view 26.3°x15°, eye movement field 12x10 mm, distance from the waveguide to the eye 15 mm, period of the crossed input and multiplying DOE 412 nm, waveguide thickness 1 mm, waveguide material PMMA with a refractive index of 1.495, internal radius of curvature of the waveguide 150 mm, distance between the center of the exit pupil of the projector and the center of the eye movement field 32.5 mm;

- in the form of a cylindrical concentric meniscus with a transfer of the field of view in the direction parallel to the axis of the cylindrical surfaces of the waveguide, with the following parameters: operating wavelength 525 nm, field of view 26.3°x15°, eye movement field 12x10 mm, distance from the waveguide to the eye 15 mm, period of the crossed input and multiplying DOE 412 nm, waveguide thickness 1 mm, waveguide material PMMA with a refractive index of 1.495, internal radius of curvature of the waveguide 270 mm, distance between the center of the exit pupil of the projector and the center of the field of eye movement 32.5 mm;

- in the form of a spherical concentric meniscus with the following parameters: operating wavelength 525 nm, field of view 26.3°x15°, eye movement field 12x10 mm, distance from the waveguide to the eye 15 mm, period of the crossed input and multiplying DOE 412 nm, waveguide thickness 1 mm, waveguide material PMMA with a refractive index of 1.495, internal radius of curvature of the waveguide 270 mm, distance between the center of the exit pupil of the projector and the center of the eye movement field 32.5 mm.

In the proposed invention, the following types of projectors can be used as a projector: MicroLED projector, DMD projector, LCoS projector, laser projector, LED projector, LCD projector, DLP projector, as well as any other suitable projector.

Any suitable optical material can be used as a waveguide, in particular, for example, glass, plastic, polymer, diamond, etc.

A volume Bragg grating, relief diffraction gratings with different profiles, as well as any other suitable DOEs can be used as a multiplying diffractive optical element.

The coating of the optical combiner (waveguide) can be anti-reflective, or have high reflectivity, or be polarizing, or have spectral filtering, and can also be UV-protective, as well as any suitable one.

The periods of the diffraction optical elements that provide input of radiation into the waveguide, multiplication of rays inside the waveguide, and output of radiation from the waveguide must be selected in such a way as to ensure physical correspondence of the input sections of the fields of view for specific segments of the diffraction gratings to the fields of view at the output of the waveguide (entering the observer's eye).

The periods of all diffractive optical elements must be coordinated to effectively propagate a light wave with specified parameters. The proposed invention can be used to display a virtual image in a user's eye wearing augmented reality glasses, as well as to project a virtual image through a curved surface, such as a car windshield, a motorcycle helmet visor, or any other curved surface.

The proposed invention's high resolution, wide viewing angle, and high image uniformity provide a realistic virtual image. A virtual image of this quality provides the user with an immersive experience in which virtual elements complement the user's environment.

The proposed solution, namely the use of a curved waveguide, a crossed DOE, and an output DOE with a variable period, distorts the parasitic virtual image formed by the device and directed toward the external environment, ensuring the protection of the virtual image presented to the user from third-party observers.

The proposed solution allows for mounting an augmented reality display on a device using curved transparent surfaces, such as a motorcycle helmet lens or a car windshield. The curved waveguide allows for the creation of a wearable augmented reality device that looks like regular glasses and can easily be combined with prescription lenses.

The proposed solution can be used in any augmented reality device, HUD or HMD, where a compact design and high-quality virtual image are required.

Although the invention has been described with certain illustrative embodiments, it should be understood that the invention is not limited to these specific embodiments. Rather, it is intended that the invention include all alternatives, modifications, and equivalents that may be included within the spirit and scope of the claims.

Furthermore, the invention includes all equivalents of the claimed invention, even if the claims are changed during the review process.

Claims (256)

1. A device for displaying augmented reality, comprising: - a projector that forms the original image; - an optical combiner, which is a curved waveguide in the form of a concentric cylindrical or concentric spherical meniscus, containing a crossed diffractive optical element (DOE) and an output DOE; wherein the crossed DOE consists of a first diffraction subgrating and a second diffraction subgrating superimposed on each other so that they represent a single diffraction structure, where the period of the first diffraction subgrating is equal to the period of the second diffraction subgrating, wherein the projector is designed with the ability to project rays forming the original image onto the crossed DOE in such a way that the rays emanating from one point of the original image fall at the same angle relative to the normal to the surface of the curved waveguide at the points of incidence, wherein the vector of the first diffraction subgrating and the vector of the second diffraction subgrating in the coordinate system associated with the normal to the surface of the curved waveguide at each point of the DOE have equal length and are rotated relative to each other by an angle of 120°, wherein the crossed DOE is designed with the possibility of: - input of radiation from the projector into a curved waveguide, - radiation propagation inside a curved waveguide, wherein the curved waveguide is configured to propagate the rays of the original image from the input diffractive optical element to the output diffractive optical element by means of total internal reflection from the surfaces of the curved waveguide, Moreover, the output DOE has a variable period, due to which a virtual image is formed from the side of the concave surface of the curved waveguide. 2. The device according to claim 1, in which the variable period of the output DOE is designed such that rays emerging from one point of the original image, passing through a curved waveguide and hitting the output DOE, are converted into parallel beams of rays. 3. The device according to claim 2, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other across the axis of the surfaces of the concentric cylindrical meniscus. 4. The device according to claim 2, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other along the axis of the surfaces of the concentric cylindrical meniscus. 5. The device according to claim 1, in which the variable period of the output DOE is designed such that rays emerging from one point of the original image, passing through a curved waveguide and hitting the output DOE, are converted into diverging beams of rays. 6. The device according to claim 5, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other across the axis of the surfaces of the concentric cylindrical meniscus. 7. The device according to claim 5, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other along the axis of the surfaces of the concentric cylindrical meniscus. 8. A device according to any one of claims 1-7, in which the period of the output DOE at the point corresponding to the center of the eye movement field is equal to the period of the subarrays of the crossed DOE. 9. A device according to any one of paragraphs 1-8, in which all the DOEs are located symmetrically to the axis in the direction of which the field of view is transferred. 10. A device according to any one of claims 1-9, in which the output DOE is designed in such a way that in the region located closer to the crossed DOE, the diffraction efficiency of the output DOE is lower than in the region located further from the crossed DOE. 11. The device according to paragraph 3, wherein the period output DOE at each point with coordinates equals: Where - offset and rotation angle to transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image beam, - the angle between the center of the input and output DOEs, - period of introductory DOE. 12. The device according to item 2, wherein if the curved waveguide has the shape of a concentric spherical meniscus, the period output DOE at each point with coordinates equals: Where Where - rotation angles for transition to a rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image, - the angle between the center of the input and output DOEs, - the period of the sublattices of the crossed DOE. 13. The device according to paragraph 6, wherein the period output DOE at each point with coordinates equals: Where Where - offset and rotation angle to transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE. 14. The device according to 5, wherein if the curved waveguide has the shape of a concentric spherical meniscus, the period output DOE at each point with coordinates equals: Where Where - rotation angles for transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE. 15. A device according to any one of paragraphs 1-14, wherein if the curved waveguide has the shape of a concentric spherical meniscus, an additional input optical compensator is used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a spherical negative lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. 16. A device according to any one of paragraphs 1-14, wherein if the curved waveguide has the shape of a concentric cylindrical meniscus, an additional input optical compensator is used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a cylindrical lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. 17. A device according to any one of claims 1-16, wherein the curved waveguide has the same thickness and the same curvature at least in the working region. 18. A method of operating a device for displaying augmented reality according to any of paragraphs 1-17, comprising the steps of: form the original image using a projector; the rays of the original image are introduced into the curved waveguide by means of one of the first or second diffraction subgratings of the crossed diffractive optical element (DOE); injected rays: propagate inside a curved waveguide at angles of total internal reflection, fall again onto the crossed DOE, undergo diffraction on one of the second or first diffraction subgratings, propagate inside the curved waveguide at angles of total internal reflection, without interacting with the crossed DOE, fall on the output DOE, and, undergoing diffraction, are removed from the waveguide, forming a virtual image. 19. A device for displaying augmented reality, comprising - a projector that forms the original image; - an optical combiner, which is a curved waveguide in the form of a concentric cylindrical or concentric spherical meniscus, containing an input diffractive optical element (DOE), a crossed DOE and an output DOE; wherein the input DOE is designed with the possibility of introducing radiation from the projector into the waveguide and has a constant period; where the vector of the input DOE in the coordinate system associated with the normal to the surface of the curved waveguide is the same at each point of the input DOE; wherein the crossed DOE consists of a first diffraction subgrating and a second diffraction subgrating superimposed on each other so that they represent a single diffraction structure, wherein the strokes of the first diffraction subgrating and the second diffraction subgrating are located symmetrically relative to the direction of transmission of the field of view along the curved waveguide, where the period of the first diffraction subgrating is equal to the period of the second diffraction subgrating; wherein the crossed DOE is designed with the possibility of multiplying radiation inside the curved waveguide; wherein the curved waveguide is configured to propagate the rays of the original image from the input diffractive optical element to the output diffractive optical element by means of total internal reflection from the surfaces of the curved waveguide; Moreover, the output DOE has a variable period, due to which a virtual image is formed from the side of the concave surface of the curved waveguide. 20. The device according to claim 19, in which the variable period of the output DOE is designed such that rays emerging from one point of the original image, passing through a curved waveguide and hitting the output DOE, are converted into parallel beams of rays. 21. The device according to claim 20, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other across the axis of the surfaces of the concentric cylindrical meniscus. 22. The device according to claim 20, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other along the axis of the surfaces of the concentric cylindrical meniscus. 23. The device according to claim 19, in which the variable period of the output DOE is designed such that rays emerging from one point of the original image, passing through a curved waveguide and hitting the output DOE, are converted into diverging beams of rays. 24. The device according to claim 23, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other across the axis of the surfaces of the concentric cylindrical meniscus. 25. The device according to claim 23, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other along the axis of the surfaces of the concentric cylindrical meniscus. 26. A device according to any one of paragraphs 19-25, in which the period of the output DOE at the point corresponding to the center of the eye movement field is equal to the period of the subarrays of the crossed DOE. 27. A device according to any one of paragraphs 19-26, in which all the DOEs are located symmetrically to the axis in the direction of which the transfer of the field of view occurs. 28. A device according to any one of claims 19-27, in which the output DOE is designed in such a way that in the region located closer to the crossed DOE, the diffraction efficiency of the output DOE is lower than in the region located further from the crossed DOE. 29. The device according to paragraph 21, wherein the period output DOE at each point with coordinates equals: Where - offset and rotation angle to transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image beam, - the angle between the center of the input and output DOEs, - period of introductory DOE. 30. The device according to claim 20, wherein if the curved waveguide has the shape of a concentric spherical meniscus, the period output DOE at each point with coordinates equals: Where Where - rotation angles for transition to a rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image, - the angle between the center of the input and output DOEs, - period of introductory DOE. 31. The device according to paragraph 24, wherein the period output DOE at each point with coordinates equals: Where Where - offset and rotation angle to transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE. 32. The device according to claim 23, wherein if the curved waveguide has the shape of a concentric spherical meniscus, the period output DOE at each point with coordinates equals: Where Where - rotation angles for transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE. 33. A device according to any one of paragraphs 19-32, wherein if the curved waveguide has the shape of a concentric spherical meniscus, an additional input optical compensator is used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a spherical negative lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. 34. A device according to any one of paragraphs 19-32, wherein if the curved waveguide has the shape of a concentric cylindrical meniscus, an additional input optical compensator is used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a cylindrical lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. 35. A device according to any one of paragraphs 19-34, in which the curved waveguide has the same thickness and the same curvature at least in the working region. 36. A method of operating a device for displaying augmented reality according to any of paragraphs 19-35, comprising the steps of: form the original image using a projector; the rays of the original image are introduced into a curved waveguide by means of an input diffractive optical element (DOE), injected rays: hit the crossed DOE, undergo diffraction on one of the first or second diffraction subgratings of the crossed DOE, propagate further at angles of total internal reflection inside the curved waveguide, undergo diffraction again on one of the second or first diffraction subgratings of the crossed DOE, propagate inside the curved waveguide at angles of total internal reflection without interacting with the crossed DOE, fall on the output DOE, and, undergoing diffraction, are output from the waveguide, forming a virtual image. 37. A device for displaying augmented reality, comprising - a projector that forms the original image; - an optical combiner, which is a curved waveguide having the shape of a concentric cylindrical or concentric spherical meniscus, containing a crossed diffractive optical element (DOE), a first multiplying DOE, a second multiplying DOE and an output DOE; wherein the crossed DOE consists of a first diffraction subgrating and a second diffraction subgrating superimposed on each other so that they represent a single diffraction structure, where the period of the first diffraction subgrating is equal to the period of the second diffraction subgrating, wherein the projector is designed with the ability to project rays forming the original image onto the crossed DOE in such a way that the rays emanating from one point of the original image fall at the same angle relative to the normal to the surface of the curved waveguide at the points of incidence, wherein the vector of the first diffraction subgrating and the vector of the second diffraction subgrating in the coordinate system associated with the normal to the surface of the curved waveguide at each point of the DOE have equal length and are rotated relative to each other by an angle of 120°, wherein the crossed DOE is designed with the possibility of introducing radiation from the projector into the curved waveguide; wherein the first multiplying DOE has the same structure as the first diffraction subgrating; wherein the second multiplying DOE has the same structure as the second diffraction subgrating; wherein the first and second multiplying DOEs are located one above the other relative to the direction of transmission of the field of view, close to each other, wherein the strokes of the first multiplying DOE and the second multiplying DOE have the same period, equal to the period of the diffraction subgratings of the crossed DOE, are symmetrical relative to the plane perpendicular to the axis of the cylindrical surfaces of the waveguide, and have an inclination to this plane equal to 30°; wherein the crossed DOE is located in the area of the exit pupil of the projector at the junction of the first multiplying DOE and the second multiplying DOE opposite the projector; wherein the curved waveguide is configured to propagate the rays of the original image from the input diffractive optical element to the output diffractive optical element by means of total internal reflection from the surfaces of the curved waveguide, Moreover, the output DOE has a variable period, due to which a virtual image is formed from the side of the concave surface of the curved waveguide. 38. The device according to claim 37, in which the variable period of the output DOE is designed such that rays emerging from one point of the original image, passing through a curved waveguide and hitting the output DOE, are converted into parallel beams of rays. 39. The device according to claim 38, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other across the axis of the surfaces of the concentric cylindrical meniscus. 40. The device according to claim 38, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other along the axis of the surfaces of the concentric cylindrical meniscus. 41. The device according to claim 37, in which the variable period of the output DOE is designed such that rays emerging from one point of the original image, passing through a curved waveguide and hitting the output DOE, are converted into diverging beams of rays. 42. The device according to claim 41, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other across the axis of the surfaces of the concentric cylindrical meniscus. 43. The device according to claim 41, in which the DOEs are located on a curved waveguide in the form of a concentric cylindrical meniscus one after the other along the axis of the surfaces of the concentric cylindrical meniscus. 44. A device according to any one of paragraphs 37-43, in which the period of the output DOE at the point corresponding to the center of the eye movement field is equal to the period of the subarrays of the crossed DOE. 45. A device according to any one of paragraphs 37-44, in which all the DOEs are located symmetrically to the axis in the direction of which the transfer of the field of view occurs. 46. A device according to any one of claims 37-45, in which the output DOE is designed in such a way that in the region located closer to the crossed DOE, the diffraction efficiency of the output DOE is lower than in the region located further from the crossed DOE. 47. The device according to paragraph 39, wherein the period output DOE at each point with coordinates equals: Where - offset and rotation angle to transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image beam, - the angle between the center of the input and output DOEs, - period of introductory DOE. 48. The device according to 38, wherein if the curved waveguide has the shape of a concentric spherical meniscus, the period output DOE at each point with coordinates equals: Where Where - rotation angles for transition to a rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - wavelength of the original image, - the angle between the center of the input and output DOEs, - the period of the sublattices of the crossed DOE. 49. The device according to paragraph 42, wherein the period output DOE at each point with coordinates equals: Where Where - offset and rotation angle to transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the grid vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE. 50. The device according to claim 41, wherein if the curved waveguide has the shape of a concentric spherical meniscus, the period output DOE at each point with coordinates equals: Where Where - rotation angles for transition to a rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the X-axis in the rotated coordinate system, - the component of the diffraction grating vector of the output DOE in the direction of the Y axis in the rotated coordinate system, - is the distance from the center of curvature of the waveguide surfaces to the plane of the virtual image, - normalizing coefficient of the beam vector at the output of the output DOE, - wavelength of radiation, - the angle between the center of the input and output DOEs, - radius of curvature of the concave surface of the waveguide, - period of introductory DOE. 51. A device according to any one of paragraphs 37-50, wherein if the curved waveguide has the shape of a concentric spherical meniscus, an additional input optical compensator is used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a spherical negative lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. 52. A device according to any one of paragraphs 37-50, wherein if the curved waveguide has the shape of a concentric cylindrical meniscus, an additional input optical compensator is used, located between the projector and the curved waveguide, to correct the radiation from the projector having an optical system that forms an image at infinity, wherein the compensator is a cylindrical lens with a focal length equal to the radius of curvature of the inner surface of the curved waveguide. 53. The device according to any one of paragraphs 37-52, in which the curved waveguide has the same thickness and the same curvature at least in the working region. 54. The method of operating the device according to paragraph 37 for displaying augmented reality, comprising the steps of: form the original image using a projector; the rays of the original image are introduced into a curved waveguide by means of a crossed diffractive optical element (DOE), beams introduced into one of the first or second diffraction subgratings of the crossed DOE: propagate inside a curved waveguide at angles of total internal reflection; undergo diffraction at each of the first multiplying DOE and the second multiplying DOE, propagate inside the curved waveguide at angles of total internal reflection towards the output DOE; fall on the output DOE and, undergoing diffraction, are removed from the waveguide, forming a virtual image. 55. Augmented reality glasses comprising an element for the left eye and an element for the right eye, wherein each of the elements for the left and right eyes is a device for displaying augmented reality according to any one of paragraphs 1-17. 56. The glasses of claim 55, wherein the curved waveguide contained in the left eye element and the curved waveguide contained in the right eye element have the same radius of curvature. 57. Glasses according to item 56, wherein in the case where the curved waveguide of each element has the shape of a concentric cylindrical meniscus, both curved waveguides have one common axis. 58. Glasses according to item 56, wherein in the case where the curved waveguide of each element has the shape of a concentric spherical meniscus, both curved waveguides have one common center of curvature. 59. Augmented reality glasses comprising a left eye element and a right eye element, wherein each of the left and right eye elements is a device for displaying augmented reality according to any one of paragraphs 19-35. 60. Glasses according to paragraph 59, wherein in the case where the curved waveguide of each element has the shape of a concentric cylindrical meniscus, both curved waveguides have one common axis. 61. Glasses according to paragraph 59, wherein in the case where the curved waveguide of each element has the shape of a concentric spherical meniscus, both curved waveguides have one common center of curvature. 62. Augmented reality glasses comprising an element for the left eye and an element for the right eye, wherein each of the elements for the left and right eyes is a device for displaying augmented reality according to any of paragraphs 37-53. 63. Glasses according to item 62, wherein in the case where the curved waveguide of each element has the shape of a concentric cylindrical meniscus, both curved waveguides have one common axis. 64. Glasses according to claim 62, wherein in the case where the curved waveguide of each element has the shape of a concentric spherical meniscus, both curved waveguides have one common center of curvature.