RU2799661C1 - Optical combiner for displaying augmented reality with correction of user's vision impairment, method of operation of the mentioned optical combiner, augmented reality glasses for displaying augmented reality with correction of user vision impairment - Google Patents

Abstract

FIELD: augmented reality devices.

SUBSTANCE: optical combiner for displaying augmented reality with correction of user visual impairment contains a compensator, a waveguide having an input diffractive optical element (DOE) and an output DOE, a virtual image projector. The waveguide has such a thickness gradient along the first and second sides of the waveguide that as the rays that form the virtual image propagate inside the waveguide from the input DOE to the output DOE, the angle of incidence of said rays on the walls inside the waveguide increases. The output DOE is located opposite the user's eye and is configured to output rays that form a virtual image, incident on the output DOE at an angle equal to or greater than the smallest angle of the predetermined range of the output DOE angular selectivity, from the waveguide to the user's eye.

EFFECT: invention enables a user with vision problems to use augmented reality glasses and see both a virtual image and a real undistorted image of the external environment without using additional medical glasses.

27 cl, 5 dwg

Description

Technical field

The present invention relates to augmented reality devices, as well as to augmented reality glasses with correction of visual impairment of the user.

Description of the prior art

Wearable augmented reality (AR) glasses are a personal device that the user can use as a source of video information (image) projected directly into the user's eye in the form of a virtual image that complements the user's real environment. When designing augmented reality glasses, it is necessary to take into account consumers with visual impairments, that is, those with farsightedness, myopia, astigmatism and other visual aberrations. It is necessary to develop devices for augmented reality glasses with a wide field of view (FOV - angular characteristic, showing in what range of angles it is possible to observe virtual images that complement the real environment around the user), low weight and cost, compactness and high resolution, as well as with optical power for users with visual impairments. Such wearable devices can replace any source of video information for the user, such as TVs, smartphones, etc.

The following requirements are imposed on augmented reality glasses systems:

- a wide field of view to enable the virtual image to be superimposed over a large area of space that the human eye can see;

- good image quality, i.e. high resolution, high contrast, etc.;

- low weight;

- compactness;

- low cost.

A user who is forced to wear medical glasses, when using augmented reality glasses, is forced to wear them over their medical glasses in order to see both the virtual image and the surrounding real world clearly and not blurry. This is uncomfortable, especially when worn for a long time.

An optical device that combines a virtual image with the real environment surrounding the user is an optical combiner. Planar (flat) waveguides, on the surface of which there are diffractive optical elements (DOE) for input, conversion and output of optical radiation, are currently the most widely used as a combiner. A planar waveguide is a transparent plate of optical material with two plane-parallel surfaces. A beam of parallel rays inside such a waveguide can propagate without distortion to any distance. Augmented reality devices with such combiners are lightweight, small in size, low in cost, can provide a wide field of view, and have high transmission, that is, high transmission of a real image.

However, in such devices, the edges where the image projectors are located are located far from the temporal part of the user's head, so such glasses take up a large space during use. In addition, such combiners form a virtual image not only from the side where the user's eye is located, but also from the side opposite from the user. This may lead to the fact that an external observer, at a certain location, will be able, just like the user, to partially or completely see the virtual image generated for the user, which may be undesirable.

As an optical combiner, it is possible to use curved waveguides located on the user's head in such a way that they go around the oval of the user's head, glasses with such a combiner will be more compact and convenient, they will have smaller dimensions, a device with such a combiner will be more ergonomic and aesthetic. However, 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 falling on a curved waveguide. Let this beam be introduced into the waveguide using an introductory diffraction grating with a constant period. A beam of parallel rays incident on the waveguide will turn inside the waveguide into a non-parallel beam, the rays of which will propagate inside the waveguide at different angles. This effect must be taken into account and compensated for when designing augmented reality glasses with a curved combiner.

From the prior art document US 10,466,477 B2 (publication date 05.11.2019) is known, which discloses an augmented reality system containing a set of planar waveguides with optical power. The image is fed from the projector through waveguides to the user's eye. The virtual image, passing through the waveguides, undergoes a transformation in accordance with the user's vision. That is, the known system corrects the virtual image according to the user's vision. The disadvantages of the known device are a large number of waveguides, each of which has its own optical power, as well as the use of a large number of deformed optical elements, which complicates the manufacture of the system. The known system is cumbersome and cannot be used for daily wear of augmented reality glasses. In the known system, the real scene is not corrected for the user's vision.

The document US 9,632,312 B1 (publication date 04/25/2017) is known from the prior art, in which an optical device is disclosed, including an optical element having a surface facing the eyes and a surface facing the external space. The optical device also includes a diffractive optical element that follows the curvature of the surface facing the eye. The curvature of the eye-facing surface of the first optical element is configured to collimate the image light in an area the size of the width of the field of view. The known device corrects only the virtual image of the image, that is, the real image is not corrected.

The document US 9,389,422 B1 is known from the prior art (publication date 07/12/2016). The head-worn display device includes an intricately shaped light guide component for guiding light received at a display peripheral position offset from the viewing area and emitting light into the viewing area. Light is introduced into the light guide component such that the light propagates within the light component by total internal reflection. Due to the shape of the prism, the light propagating inside changes its angle of reflection, and thus, after several reflections, some of the light ceases to experience total internal reflection and exits the light guide component. To equalize the brightness of the displayed image, partially reflective coatings are applied in the region of the user's eyes, which is a drawback of the solution, since the partial reflective coating reduces the brightness of the light from the real scene. That is, in the known solution, the image of the real scene is not corrected.

The closest analogue of the present invention is the solution disclosed in the document US 2021/0389592 A1 (publication date 12/16/2021). The known solution uses a free-form waveguide through which a virtual image is transmitted. An additional optical element is glued to the waveguide using a viscous or liquid substance. The device corrects the image of both the virtual scene and the real scene depending on the user's vision problems. The main disadvantages of the known solution is that the waveguide and the additional optical element are glued together, which imposes restrictions on the conditions of total internal reflection inside the waveguide, since it is the contrast between the refractive index of the waveguide and the environment that is the key factor for expanding the range of angles at which the image is transmitted. virtual reality, that is, the field of view. In the case of a well-known solution, part of the rays will propagate in the substance with which an additional optical element is glued to the waveguide, which means that the field of view is limited and the quality of the virtual reality display deteriorates.

Thus, it is necessary to create augmented reality glasses devices with a wide field of view, low weight and cost, compactness and high resolution, as well as with optical power for users with visual impairments.

The essence of the invention

An optical combiner is proposed for displaying augmented reality with correction of visual impairment of the user, containing:

compensator;

waveguide;

virtual image projector;

moreover, the compensator is configured to pass the image of the external environment through its first side, located opposite the external environment, and its second side, opposite to the first side,

moreover, the waveguide has a first side located on the side of the user and a second side opposite the first side, on one of the said sides there are an input diffractive optical element (DOE) and an output DOE, the first side of the waveguide has a curvature, the center of which is located on the side of the user's eye;

moreover, between the second side of the compensator and the second side of the waveguide, a gap is provided, configured to pass the image of the external environment that has passed the compensator into the waveguide;

moreover, the waveguide is configured to transmit an image of the external environment, and output it through the output DOE to the user's eye;

moreover, the compensator, the gap and the waveguide are configured to correct visual impairment of the user when the user views the image of the external environment;

moreover, the projector of the virtual image is located with the possibility of introducing beams that form a virtual image through the input DOE into the waveguide;

moreover, the waveguide is configured to propagate the virtual image-forming beams from the input DOE to the output DOE by means of total internal reflection from the walls inside the waveguide, and to output the virtual image through the output DOE to the user's eye,

moreover, the waveguide has a thickness gradient along the first and second sides of the waveguide such that as the rays that form the virtual image propagate inside the waveguide from the input DOE to the output DOE, the angle of incidence of said rays on the walls inside the waveguide increases;

moreover, the output DOE is located opposite the user's eye, and is configured to output rays that form a virtual image, incident on the output DOE at an angle equal to or greater than the smallest angle of the predetermined range of the output DOE angular selectivity, from the waveguide to the user's eye.

The gap may have the same thickness along its entire length. The gap may have a thickness gradient along the compensator and waveguide. The gap may have a thickness gradient in the direction from the compensator to the waveguide. The gap may have a thickness gradient in the direction from the waveguide to the compensator. The compensator may be shaped such that the gap is curved. The waveguide may be shaped such that the gap is curved. The compensator and waveguide may be shaped such that the gap is straight. The compensator, gap, and waveguide may be configured to function as a divergent lens. The compensator, gap, and waveguide may be configured to function as a converging lens. The compensator, gap, and waveguide may be configured to function as a cylindrical lens. The compensator, gap, and waveguide may be configured to function as a toric lens. The compensator and the waveguide can be fixed in the frame in such a way that they are separated by a gap. The gap may be air. The gap may be filled with liquid. The liquid may be a photochromic liquid. The gap may be a layer of liquid crystals. The output DOE can be formed by a layer of liquid crystals. The output DOE can be written as a holographic diffraction grating. The output DOE can be a relief-phase selective diffraction grating. The output DOE can be recorded as a multiplex hologram. The output DOE may be a volumetric Bragg grating with angle-selective diffraction. The output DOE may be located on the first surface of the waveguide. The output DOE may be located on the second surface of the waveguide. The diffraction efficiency of the output DOE can be over 90%.

A method is proposed for the operation of the mentioned optical combiner for displaying augmented reality with correction of visual impairment of the user, containing the steps at which:

A) display a virtual image in the user's eye as follows:

generating a virtual image by means of a virtual image projector;

by means of an introductory DOE, rays forming a virtual image are introduced into the waveguide,

moreover, the rays that form the virtual image propagate from the input DOE to the output DOE in the waveguide mode by means of total internal reflection from the walls inside the waveguide,

moreover, as the rays that form a virtual image propagate inside the waveguide from the input DOE to the output DOE, the angle of incidence of said rays on the walls inside the waveguide increases;

outputting the virtual image forming beams to the user's eye by means of the output DOE in such a way that only the rays incident on the output DOE at an angle equal to or greater than the smallest angle of the predetermined range of output DOE angular selectivity are output,

in this case, the remaining beams propagate further along the waveguide, increasing their angle of incidence on the waveguide walls, and are output at the point of the output DOE, where their angle of incidence on the output DOE becomes equal to or greater than the smallest angle of the predetermined range of angular selectivity of the output DOE;

B) display an image of the external environment in the user's eye as follows:

passing the image of the external environment through the compensator, the gap, the waveguide containing the input DOE and the output DOE, correcting the image of the external environment in accordance with the impairment of the user's vision, while the DOE does not affect the transmitted radiation from the environment and only passes it;

steps (A) and (B) are carried out simultaneously, forming on the user's retina an image of the external environment, corrected to compensate for the user's visual impairment, supplemented by a virtual image.

Augmented reality glasses are provided comprising a left eye element and a right eye element, wherein each of the left and right eye elements is an inventive optical combiner for displaying augmented reality with correction of a user's visual impairment.

Brief description of the drawings

The above and other features and advantages of the present invention are explained in the following description, illustrated by drawings, in which the following is presented:

Fig. 1 illustrates an optical combiner according to the present invention.

Fig. 2 illustrates the operation of the input diffractive optical element (DOE), as well as the operation of the output DOE.

Fig. 3 illustrates two forms of gaps.

Fig. 4 illustrates the shapes of the optical combiner, a) with myopia, b) with hyperopia, c) with astigmatism.

Fig. 5 illustrates the location of the output DOE, a) on the waveguide surface closest to the user's eye, b) on the opposite waveguide surface adjacent to the gap.

Detailed description of the invention

The proposed invention enables a user with vision problems to use augmented reality glasses and see without distortion both a virtual image and a real image of the external environment without the use of additional medical glasses. The proposed device also allows you to increase the field of view, has a low weight and cost, compactness and high resolution.

The following terms are used in describing the present invention:

A virtual image is an imaginary image obtained by the continuation of rays that do not converge in the space of objects. The essence of a virtual image for use in augmented reality devices is that such an image must be imaginary, otherwise the user will not see it. A real image is a real image of physically existing objects.

An optical combiner is an optical device that provides the formation of a virtual image in front of the user that complements the real environment around the user, while not interfering with the user's observation of the real environment. As an optical combiner in this application, a waveguide with a thickness gradient is used, having an input DOE (diffractive optical element) and an output DOE, the centers of which are located in the same plane with the normals to the surface of the waveguide at these points.

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

Eye motion box (EMB) is an area within which the eye, moving, can see the entire field of view formed by the augmented reality device without loss and with a given quality, that is, the entire field of view falls into the pupil of the eye, namely , rays from anywhere in the image. Outside this area, part of the field of view is lost partially or completely, i.e. outside this area, the rays from all or from some part of the virtual image do not enter the entrance pupil of the eye. The eye is constantly moving, rotating and at the same time the pupil of the eye is constantly shifting. The eye movement field of the optical combiner of the augmented reality device must correspond to the range of possible eye movement of the user.

The exit pupil (or the pupil of the optical system) is a paraxial image of the aperture stop in image space, formed by the next part of the optical system in the forward path of the rays. This term is well-established in optics. The main property of the exit pupil is that at any point there are rays that form the entire field of view. In waveguide optics, technical solutions are known for multiplying the exit pupil, that is, increasing its size, without increasing the size of the optical system in the direction of the optical axis. Classical optics allows you to increase the size of the exit pupil, but at the same time, the size of the optical system increases significantly, waveguide optics, due to the multiple reflection of beams of rays inside the waveguide, allows you to do this without increasing the dimensions in the direction of the optical axis of the optical system.

On FIG. 1 shows an optical combiner. According to the invention, an optical combiner is manufactured for a specific user with vision problems.

The optical combiner consists of two parts, in Fig. 1 shows a first optical combiner part 1 and a second optical combiner part 2. The first part 1 of the optical combiner is a waveguide 1 for delivering a virtual image to the user's eye. The waveguide 1 has a first side located on the side of the user's face and a second side opposite the first side. On one of the first or second sides there are inlet 3 DOE and output 4 DOE. Moreover, the DOE output 4 is located opposite the user's eye 5 and displays a virtual image in the user's eye in parts, as will be described below. The first side of the waveguide has a curvature centered on the side of the user's eye 5, and the waveguide 1 also has a thickness gradient along the first and second sides of the waveguide. The curvature of the waveguide is necessary so that the rays that come out of the waveguide using the output 4 DOE propagate at different angles and thereby form an image at the exit from the waveguide corresponding to the image supplied to the input 3 DOE. That is, the rays emerging from the waveguide in the part of the output 4 DOE located closer to the user's temple, and corresponding to one edge of the image, will have a maximum angle of incidence on the eye. The rays emerging from the waveguide in the part of the output 4 DOE, located closer to the user's nose, and corresponding to the second, opposite, edge of the image, will have a minimum angle of incidence on the eye. In this case, rays corresponding to the center of the image will emerge from the center of the output 4 DOE.

The projector 6 of the virtual image is located with the possibility of supplying a virtual image through the inlet 3 of the DOE to the waveguide 1.

The second part of the optical combiner is the compensator 2. The compensator 2 together with the waveguide 1 are used to compensate for the vision of a user with vision problems. The compensator 2 passes the real image of the external environment to the waveguide, which is transparent for the image of the external environment, then the image of the external environment, compensated for the user's vision, enters the user's eye. The compensator 2 has a first side and a second side opposite the first side. The first side of the compensator 2 is located opposite the external environment. The second side of the compensator 2 is located opposite the second side of the waveguide 1. The length of the second side of the waveguide 1 is equal to the length of the second side of the compensator 2. A gap 7 is provided between the second side of the compensator 2 and the second side of the waveguide 1.

It should be noted that the radiation that makes up the virtual image does not leave the waveguide in the direction of the gap, but propagates in the waveguide through total internal reflection from the walls of the waveguide. Light from the external environment passes through the compensator, gap, waveguide and enters the eye. The compensator 2, the gap 7 and the waveguide 1 form a conventional corrective eyeglass lens that corrects visual impairments of the user. The user's vision is compensated as in normal corrective glasses (see, for example, https://studfile.net/preview/10641980/page:2/). The gap, made in the form of a plane-parallel plate, does not introduce any distortion into the transmitted radiation, which makes up the real image. For example, when it is necessary to correct myopia, the structure consisting of the waveguide, the gap, and the compensator is made such that it has the properties of a lens with a negative optical power, and when it is necessary to correct farsightedness, the structure consisting of the waveguide, the gap, and the compensator is made such that it has the properties positive lens.

The gap 7 may have the same thickness along the second side of the waveguide and the second side of the compensator. Also, the gap 7 may have a different thickness along the second side of the waveguide and the second side of the compensator, that is, the gap may have a thickness gradient along the second side of the waveguide and the second side of the compensator.

The compensator 2 may or may not have a thickness gradient along the first and second sides of the compensator.

The optical combiner may be of any shape suitable for the wearer, such as the same shape as a spectacle lens.

Radiation from the external environment does not enter the waveguide regime in waveguide 1, but passes through waveguide 1, experiencing only refraction in the waveguide. The radiation that forms the virtual image propagates along the waveguide 1 in the waveguide mode, that is, experiencing TIR (total internal reflection) from the walls of the waveguide. The compensator 2 and the waveguide 1 are fixed, for example, in the frame, so that a gap is formed between them.

Fig. 2 illustrates the waveguide 1 and the arrangement and operation of the DOE inlet 3 and DOE out 4. As described above, the input 3 DOE and the output 4 DOE are located either on the first side of the waveguide 1 or on the second side of the waveguide 1. The output 4 DOE is located opposite the user's eye 5 and displays a virtual image in the user's eye 5.

In FIG. 2 shows a virtual image of a locomotive, which from the projector enters the waveguide through the input 3 of the DOE. As you know, the projector transforms a linear image into an angular one, that is, the virtual image projected by the projector consists of rays, the angles of incidence of which on the input DOE decrease sequentially from one edge of the image to the opposite edge of the image. That is, the input angle of the rays constituting the virtual image increases along the length of the image, if the image is viewed, for example, from left to right, then the beam constituting the image to the right of the previous beam is entered at an angle smaller than the input angle of this previous beam. For example, in FIG. 2, the image in the form of a train projected by the projector consists of rays, the angles of incidence of which on the introductory DOE decrease from the leftmost car to the rightmost one. In other words, the angles of incidence on the input DOE of the rays that make up the image of the leftmost car are greater than the angles of incidence on the input DOE of the rays that make up the image of the rightmost car. When propagating inside the waveguide, the angles of incidence/reflection (hereinafter, only the term "angle of incidence" will be referred to, since the angle of incidence is equal to the angle of reflection) of the beams that make up the image to/from the wall of the waveguide increase linearly as the beam travels inside the waveguide, since the thickness of the waveguide increases along direction from the input DOE to the output DOE (waveguide thickness gradient). The dotted rectangular frame shows the change in the angle of incidence of the beam on the walls inside the waveguide between two adjacent incidences of the same beam, on the same wall of the waveguide as the rays move inside the waveguide (for clarity, an image of a locomotive is shown, which consists of rays moving inside waveguide). It can be clearly seen that the angle of incidence of each beam that makes up the image increases as it passes through the waveguide by a certain amount (the value of δ in the graph in the box).

The present invention uses diffraction angle selective output of a virtual image to the user's eye. From each area of the output 4 DOE, for example, in FIG. 2 shows areas (a), (b), (c), only a part of the radiation incident on the output DOE at an angle range determined during manufacture, called the output DOE angular selectivity range, is output due to diffraction, to output the rays constituting the virtual image . To do this, the output 4 DOE is selective in terms of the angle of incidence of radiation on it, that is, it has a different diffraction efficiency for different angles of incidence of radiation on the output DOE. As shown in FIG. 2 in a circular frame, the angle of incidence of the beam at the output DOE is the angle between the beam and the normal to the output DOE at the point of incidence. For a certain range of angles of incidence, which is the selectivity range of the output DOE, the diffraction efficiency of the output DOE must be high, then the beam incident on the output DOE at an angle equal to or greater than the smallest angle of the predetermined range of the output DOE angular selectivity will be output from waveguide into the user's eye. For all other angles of incidence smaller than the values of the angles included in the mentioned range of the angular selectivity of the output DOE, the diffraction efficiency of the output DOE must be low so that such radiation does not leave the waveguide, but passes further along the waveguide. The selectivity range of the output DOE is selected and calculated at the manufacturing stage and depends on the initial requirements for the virtual image, such as size, contrast, resolution, uniformity, etc. The selectivity range limits the removal from the waveguide of the rays incident on the output DOE at an angle smaller than the angle specified during the output DOE manufacturing, while all the rays incident on the output DOE at an angle greater than the angle specified during the output DOE manufacturing are output to the user's eye.

As a selective output DOE, for example, a holographic diffraction grating, a relief-phase selective grating, a volumetric Bragg grating with angle-selective diffraction can be used. For example, diffraction gratings known from the prior art with an angular selectivity contour width at half maximum of less than 10° can be used, the condition depends on the specific implementation and requirements for the optical system.

Preferably, the diffraction efficiency of the output 4 DOE is more than 90%. To implement such an output DOE, it is possible to use a DOE with a constant period along the propagation of radiation along the waveguide. Due to the fact that the waveguide 1 has a thickness gradient from the input DOE to the output DOE, when radiation passes along the waveguide by means of TIR, the angle of incidence of radiation on the walls inside the waveguide changes, namely, it increases. The radiation that makes up the virtual image propagating in the waveguide is a set of beams of rays with different angles of incidence. Moreover, each beam of rays, when output to the user's eye, forms one of the parts (in the form of a point) of the virtual image. In the course of radiation propagation in the waveguide at the beginning of the output DOE (zone (a) in Fig. 2), rays are output, the angles of incidence of which correspond to the selectivity range of the output DOE specified during manufacture, as described above, that is, the rays with the largest angles of incidence on output DOE that correspond to the edge of the virtual image, that is, in FIG. 2, left car. Radiation incident on the output DOE with smaller angles than the angles of incidence from the mentioned range propagates further along the waveguide. After re-reflection in the waveguide, the angle of incidence of the rays that did not leave the waveguide in zone (a) will increase due to the thickness gradient of the waveguide. Those beams, the angles of incidence of which on the output DOE will correspond to the selectivity range of the output DOE, will be output from the waveguide to the user's eye (zone (b) in Fig. 2). Radiation incident on the output DOE with smaller angles than the angles of incidence from the mentioned range will again propagate further along the waveguide. Further, after re-reflection in the waveguide, the angle of incidence of the rays that did not leave the waveguide in zone (b) will increase due to the gradient of the waveguide thickness. And again, those beams whose angles of incidence on the output DOE will correspond to the selectivity range of the output DOE will be output from the waveguide to the user's eye (zone (c) in Fig. 2). And this will happen until all the radiation that makes up the virtual image is displayed in the user's eye. Division into zones (a), (b), (c) in Fig. 2 is conditional and is given for clarity. Thus, the rays constituting the virtual image are output from the waveguide as the angle of incidence of the beam at the output DOE becomes corresponding to the selectivity range of the output DOE.

For example, as seen from FIG. 2, the beam constituting one of the points of the virtual image, shown as a solid line inside the waveguide 1, at points (a), (b), (c) of the output DOE has a different, increasing angle of incidence on the output DOE. Due to the selectivity of the output DOE, the beam shown, hitting the output DOE at point (a), is not output from the waveguide, since its angle of incidence is smaller than the angles of incidence included in the selectivity range of the output DOE, so the beam diffracts into the zero order of diffraction and passes further along waveguide through air defense. As soon as the angle of incidence of the beam under consideration satisfies the selectivity conditions of the output DOE, then diffraction will occur, in which the first order of diffraction will prevail, and the radiation will exit the waveguide, in this example from point (c). That is, for angles of incidence smaller than the angles of incidence included in the selectivity range of the output DOE, the diffraction efficiency is low and the radiation diffracts into the zero order of diffraction and is not output from the waveguide. For angles of incidence within the selectivity range of the output DOE, the diffraction efficiency reaches values close to 100%, i.e., the radiation diffracts into the first order of diffraction and will be extracted from the waveguide.

The image of the external environment, corrected in accordance with the visual impairment of the user, with the help of a compensator, a gap and a waveguide, enters the user's retina simultaneously with the virtual image, so the user with visual impairments clearly sees the image of the external environment, which is complemented by a virtual image.

The proposed augmented reality glasses are a left eye element and a right eye element, with each of the left and right eye elements being an optical combiner for displaying augmented reality with correction of the user's visual impairment as described above. The use of planar waveguides for augmented reality glasses is not energy efficient, in addition, when using planar waveguides, there is a loss of radiation, since not all radiation enters the user's eye directly. When using curved waveguides, radiation is also lost, and the virtual image is fuzzy and has aberrations. Therefore, the shape of the waveguide must be such that the virtual image is output at the same angles at which it entered the waveguide. In this case, the selective output DOE outputs parts of the field of view that are known to fall within the field of eye movement. The combination of the shape of the waveguide, the thickness of which increases from the beginning of the input DOE to the end of the output DOE, and the highly selective output DOE compensates for aberrations by reducing the area through which the radiation exits, that is, due to vignetting, while the user sees a clear image focused in his eye.

The gap shape can be either constant or varying from left to right and/or top to bottom in such a way that the gap shape provides an increase in the thickness of the waveguide from the input DOE to the end of the output DOE, that is, the gap can have a thickness gradient along its length or in the direction from the compensator to the waveguide or from the waveguide to the compensator. This is necessary when using the system for users with visual impairments such as strabismus.

In FIG. 3 shows examples of gap shapes - a curved gap (a) and a straight gap (b). If the compensator and/or waveguide have a curved shape of the second surface, then the gap will be curved. An optical combiner with a curved gap is more difficult to manufacture, but this shape of the gap provides an additional correction parameter.

In FIG. 4 shows the shapes of the optical combiner that can be used:

a) in case of myopia, the optical combiner is made in such a way that it performs the function of a concave lens (diffusing lens);

b) with farsightedness, the optical combiner is made in such a way that it performs the function of a convex lens (converging lens);

c) with astigmatism, the optical combiner is made in such a way that it performs the function of a cylindrical or toric lens.

It should be noted that for the correction of various visual defects, only the shapes of the compensator differ, while the shapes of the waveguide can remain the same in all cases.

The proposed augmented reality glasses that correct the user's vision are made, like ordinary medical glasses, individually after measuring the user's vision, eye and head parameters, that is, according to the parameters of each specific user. According to the individual parameters of the user, optical combiners for the right and left eyes are made by choosing the shape of the compensator, for example, one of those shown in Fig. 4, and by calculating the optical combiner system (compensator-gap-waveguide) depending on the individual parameters of the user's vision. Elements for the right and left eyes, which are manufactured optical combiners, are enclosed in a frame selected by the user, and the distance between the centers of the output DOEs corresponds to the interpupillary distance of the user.

The gap may be filled with a liquid, in particular a photochromic liquid, which darkens with increasing sunlight.

The gap can be filled with a layer of liquid crystals. Such a layer can play the role of a diffractive optical element in order to make part of the system opaque, while a polarizer is placed in front of the LC layer, some of the LC molecules can be oriented into a periodic structure, on which part of the radiation from the real image will diffract beyond the aperture of the eye and thus will become invisible to the eye. The virtual image will propagate in the waveguide as before, but will appear to the user with more contrast in the shading region.

An output DOE can be made of a layer of liquid crystals, such an output DOE can turn on, that is, output a virtual image and turn off, that is, not output a virtual image, under the influence of an electric field, such DOEs are known from the prior art. Also, the output DOE can be made in the form of a holographic diffraction grating or a relief-phase diffraction grating. Such gratings can be made selective by thickness and pattern, as is known in the art.

The period of the output DOE can be both constant and variable along the length of the diffraction grating. In this case, the output DOE will work as a diffractive lens with optical power, directing radiation into the user's eye at such angles that the user will see a virtual image corrected for his vision, however, this option is not the subject of the present invention. From the prior art diffractive lenses are known, in which the periodicity of the structure changes, and at the same time they have optical power. Similarly, an output DOE with a variable period can have an optical power.

Fig. 5 illustrates the location of the output DOE a) on the waveguide surface closest to the user's eye (on the first waveguide surface), b) on the opposite waveguide surface adjacent to the gap, opposite the user's eye (on the second waveguide surface). In case a), an uncorrected virtual image enters the user's eye if the output DOE period is constant. In case b), the waveguide is a corrective lens for the virtual image. The parameters of the waveguide for myopia, hyperopia, astigmatism must be calculated for each specific case, such calculations are known from the prior art.

The output DOE can be a multiplex hologram, which is a more complex diffractive structure that includes several elementary diffractive elements.

For example, an output DOE can be formed by several multiplex holograms with the following parameters:

- diffraction efficiency, for example, 33%-50%-100%); 25%-

33%-50%-100% (for 4 holograms), etc.

- angular selectivity <10° for each hologram;

- unequal periods of holograms.

This leads to an increase in the field of eye movement and allows the user to observe the image at different eye positions.

The use of multiplex holograms with unequal periods makes it possible to correct chromatism and/or equalize color intensity for the virtual RGB image.

It is possible to use several output DOEs, each of which works with its own part of the image. The first output DOE, which should output the left side of the image, has the lowest diffraction efficiency, that is, when diffracted by the first output DOE, a zero order of diffraction is formed, which is not output from the waveguide. In this case, the zero order of diffraction allows the left part of the image to propagate further along the waveguide with an increase in the angle of incidence. The second DOE has selectivity in a different range of incidence angles adjacent to the first one, and the second DOE outputs that part of the radiation that diffracted into the zero order of diffraction on the first DOE and was not extracted from the waveguide, this part of the radiation is output and propagates towards the eye under that the same angle as from the first DOE and so on. Efficiency of the third DOE outputs only the right part of the image with maximum efficiency, since it works with the largest angles of incidence.

Thus, the present invention makes it possible to obtain high-quality virtual and real images without the use of additional prescription glasses for users with visual acuity problems, and reduces user eye fatigue. The invention is distinguished by a convenient design and ergonomics for use in augmented reality glasses. The invention also makes it possible to implement additional functions in augmented reality glasses, such as sun protection, to use occlusive, varifocal lenses for the manufacture of a waveguide, so that a virtual image can be rearranged along the distance.

The proposed invention can be used in any AR, HUD, HMD devices where it is necessary to have a compact design and high image quality for users with different visual acuity.

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

In addition, the invention includes all equivalents of the claimed invention, even if the claims are changed in the course of consideration.

Claims (49)

1. Optical combiner for displaying augmented reality with correction of visual impairment of the user, containing: compensator; waveguide; virtual image projector; moreover, the compensator is configured to pass the image of the external environment through its first side, located opposite the external environment, and its second side, opposite to the first side, moreover, the waveguide has a first side located on the side of the user and a second side opposite the first side, on one of the said sides are the input diffractive optical element (DOE) and the output DOE; moreover, between the second side of the compensator and the second side of the waveguide, a gap is provided, configured to pass the image of the external environment that has passed the compensator into the waveguide; moreover, the waveguide is configured to transmit an image of the external environment; moreover, the compensator, the gap and the waveguide are configured to correct visual impairment of the user when the user views the image of the external environment; moreover, the projector of the virtual image is located with the possibility of introducing beams that form a virtual image through the input DOE into the waveguide; moreover, the waveguide is configured to propagate the virtual image-forming beams from the input DOE to the output DOE by means of total internal reflection from the walls inside the waveguide, and to output the virtual image through the output DOE to the user's eye, moreover, the waveguide has a thickness gradient along the first and second sides of the waveguide such that as the rays that form the virtual image propagate inside the waveguide from the input DOE to the output DOE, the angle of incidence of the said rays on the walls inside the waveguide increases, the first side of the waveguide has a curvature, the center of which is located from the side of the user's eye; moreover, the output DOE is located opposite the user's eye and is configured to output rays that form a virtual image, incident on the output DOE at an angle equal to or greater than the smallest angle of the predetermined range of output DOE angular selectivity, from the waveguide to the user's eye. 2. An optical combiner according to claim 1, wherein the gap has the same thickness along its entire length. 3. An optical combiner according to claim 1, wherein the gap has a thickness gradient along the compensator and waveguide. 4. An optical combiner according to claim 1, wherein the gap has a thickness gradient in the direction from the compensator to the waveguide. 5. An optical combiner according to claim 1, wherein the gap has a thickness gradient in the direction from the waveguide to the compensator. 6. An optical combiner according to claim 1, wherein the compensator is shaped such that the gap is curved. 7. An optical combiner according to claim 1, wherein the waveguide is shaped such that the gap is curved. 8. The optical combiner of claim 1, wherein the compensator and waveguide are shaped such that the gap is straight. 9. An optical combiner according to claim 1, wherein the compensator, gap, and waveguide are configured to function as a diverging lens. 10. An optical combiner according to claim 1, wherein the compensator, gap, and waveguide are configured to function as a converging lens. 11. The optical combiner of claim 1, wherein the compensator, gap, and waveguide are configured to function as a cylindrical lens. 12. The optical combiner of claim 1, wherein the compensator, gap, and waveguide are configured to function as a toric lens. 13. Optical combiner according to any one of paragraphs. 1-12, in which the compensator and the waveguide are fixed in the frame in such a way that they are separated by a gap. 14. Optical combiner according to any one of paragraphs. 1-13, in which the gap is air. 15. Optical combiner according to any one of paragraphs. 1-13, in which the gap is filled with liquid. 16. The optical combiner of claim 15, wherein the liquid is a photochromic liquid. 17. Optical combiner according to any one of paragraphs. 1-13, in which the gap is formed by a layer of liquid crystals. 18. Optical combiner according to any one of paragraphs. 1-17, in which the output DOE is made of a layer of liquid crystals. 19. Optical combiner according to any one of paragraphs. 1-17, in which the output DOE is written as a holographic diffraction grating. 20. Optical combiner according to any one of paragraphs. 1-17, in which the output DOE is a relief-phase selective diffraction grating. 21. Optical combiner according to any one of paragraphs. 1-17, in which the output DOE is recorded as a multiplex hologram. 22. Optical combiner according to any one of paragraphs. 1-17, in which the output DOE is a volume Bragg diffraction grating with angle-selective diffraction. 23. Optical combiner according to any one of paragraphs. 1-22, in which the output DOE is located on the first surface of the waveguide. 24. Optical combiner according to any one of paragraphs. 1-22, in which the output DOE is located on the second surface of the waveguide. 25. Optical combiner according to any one of paragraphs. 1-24, in which the diffraction efficiency of the output DOE is more than 90%. 26. The method of operation of the optical combiner for displaying augmented reality with the correction of visual impairment of the user according to any one of paragraphs. 1-25, containing the steps in which: A) display a virtual image in the user's eye as follows: generating a virtual image by means of a virtual image projector; by means of an introductory DOE, rays forming a virtual image are introduced into the waveguide, moreover, the rays that form the virtual image propagate from the input DOE to the output DOE in the waveguide mode by means of total internal reflection from the walls inside the waveguide, moreover, as the rays that form a virtual image propagate inside the waveguide from the input DOE to the output DOE, the angle of incidence of said rays on the walls inside the waveguide increases; outputting the virtual image-forming beams to the user's eye by means of the output DOE, so that only the rays incident on the output DOE at an angle equal to or greater than the smallest angle of the predetermined angular selectivity range of the output DOE are output, in this case, the remaining beams propagate further along the waveguide, increasing their angle of incidence on the waveguide walls, and are output at the point of the output DOE, where their angle of incidence on the output DOE becomes equal to or greater than the smallest angle of the predetermined range of angular selectivity of the output DOE; B) display an image of the external environment in the user's eye as follows: passing the image of the external environment through the compensator, the gap and the waveguide, correcting the image of the external environment in accordance with the visual impairment of the user, steps (A) and (B) are carried out simultaneously, forming on the user's retina an image of the external environment, corrected to compensate for the user's visual impairment, supplemented by a virtual image. 27. Augmented reality glasses containing an element for the left eye and an element for the right eye, and each of the elements for the left and right eyes is an optical combiner for displaying augmented reality with correction of visual impairment of the user according to any one of paragraphs. 1-25.

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