RU2772076C2 - Light guide optical element with multi-axis expansion of internal aperture - Google Patents

Abstract

FIELD: optical devices.

SUBSTANCE: optical device contains a light guide having a first pair of outer surfaces parallel to one another, and at least two sets of faces, each of which includes a plurality of partially reflecting faces parallel to one another, and is located between the first pair of outer surfaces. In each of the sets of faces, the corresponding faces are located at an oblique angle with respect to the first pair of outer surfaces and non-parallel with respect to the other of the said sets of faces. In this case, if there is a first set of lines of intersection between the planes of the first set of faces with the plane of the outer surface of the light guide and if there is a second set of lines of intersection between the planes of the second set of faces with the same plane of the outer surface of the light guide, the first and second sets of lines are non-parallel.

EFFECT: expanding the internal aperture in at least two dimensions.

29 cl, 51 dwg

Description

Technical field

The present invention generally relates to optical aperture expansion.

Prerequisites for the creation of the invention

An AR head-mounted display uses a projector having a small aperture and a light guide that enlarges (expands) that small aperture to project a larger aperture to illuminate the desired focal area. If the projected aperture is wide, then the expansion occurs in one dimension. If the projected aperture is small (for example, in the case of a two-dimensional (2D) light guide), then the expansion of the light guide occurs in two dimensions.

The essence of the invention

In some embodiments, the implementation of the present invention provides a light guide optical element with the expansion of the internal aperture of at least two dimensions. Thus, in accordance with one embodiment of the present invention, an optical device is provided, comprising (a) a light guide having: (i) a first pair of outer surfaces parallel to one another, and (ii) at least two sets of faces, each of the sets: (A) includes a plurality of partially reflecting faces parallel to one another, and (B) is located between said first pair of outer surfaces, and (b) wherein in each of said sets of faces, the respective faces are located (i) under the oblique an angle with respect to said first pair of outer surfaces, and (ii) non-parallel with respect to another of said sets of faces.

According to another feature of one of the embodiments of the present invention, said light guide comprises two of said facet sets in total.

In accordance with another feature of one of the embodiments of the present invention, the light guide contains all three of the said sets of faces.

In accordance with another feature of one of the embodiments of the present invention, at least a first set of said sets of facets provides a continuous overlap when viewed in the direction of view of the corresponding location of the said first set of faces, so that at least part of the light in the mentioned direction of view passes through at least one face from at least two sets of faces in said light guide.

In accordance with another feature of one of the embodiments of the present invention, each of said sets of faces fills the area of overlap, while said filling is the location of each of the mentioned sets of faces, and at the same time, said areas of overlap of two of the mentioned sets of faces at least partially overlap.

In accordance with another feature of one of the embodiments of the present invention, the light guide is a single-section light guide, including: (a) the first set of said sets of faces, and

(b) a second set of said sets of facets, wherein said first and second sets overlap in the same plane along the thickness of said light guide, said thickness being defined between said first pair of outer surfaces.

In accordance with another feature of one of the embodiments of the present invention (a) said light guide has a thickness defined between said first pair of outer surfaces, (b) faces of the first of said sets of faces extend through said thickness so as to enclose the first layer from the first value thickness to the second thickness value, and

(c) the faces of the second of said sets of faces extend through said thickness so as to enclose the second layer from a third thickness value to a fourth thickness value.

According to another feature of one embodiment of the present invention, said first layer and said second layer encompass overlapping layers.

According to another feature of one of the embodiments of the present invention, said first layer and said second layer cover the same thickness of the layers.

According to another feature of one embodiment of the present invention, said first layer and said second layer do not overlap.

In accordance with another feature of one of the embodiments of the present invention, the section of faces is limited by a bounding pair of surfaces parallel to or coinciding with said first pair of external surfaces, while said section contains at least one of the mentioned sets of faces.

According to another feature of one embodiment of the present invention, said light guide is a single section light guide including a first section of said facet section, said first section comprising two of said facet sets.

In accordance with another feature of one of the embodiments of the present invention, said light guide is a two-section light guide, including: (a) a first section of said facet section containing a first bounding pair of surfaces, and (b) a second section of said facet section containing a second bounding pair of surfaces, wherein one surface of said first bounding pair of surfaces is adjacent to one surface of said second bounding pair of surfaces, wherein said first and second bounding pairs of surfaces are parallel.

In accordance with another feature of one of the embodiments of the present invention, said light guide is a three-section light guide, also including a third section of said edge section, containing a third bounding pair of surfaces, wherein one surface of said third bounding pair of surfaces is adjacent to one surface or said a first bounding pair of surfaces, or said second bounding pair of surfaces, wherein said third bounding pair of bounding surfaces is parallel to said first and second bounding pairs of surfaces.

According to another feature of one of the embodiments of the present invention, said light guide includes (a) a first section of said edge section, comprising a first boundary pair of surfaces, and (b) a second section of said edge section, comprising a second boundary pair of surfaces, (c) wherein said first and second boundary pairs of surfaces are parallel; and (d) at least one contact surface, wherein each said contact surface (i) is at least partially between the two sections, and (ii) is parallel to said first pair of outer surfaces, (e) wherein said contact surface is at least one surface selected from the group consisting of: (i) a partially reflective surface, (ii) a partially reflective optical coating, (iii) a transitional area from the material of one of the sections to another material of the other of the said sections, (iv) a coating, polarization-changing; and (v) a flexible interlayer.

According to another feature of one of the embodiments of the present invention, the second of said sets of facets is configured to output light from said light guide, wherein said second set of faces, having a fixed number of faces, overlaps along the optical axis in the direction of a predetermined viewpoint of the output. light from said light guide through one of said first pair of outer surfaces.

According to another feature of one embodiment of the present invention, there is also provided (a) an input device configured to direct light into said light guide so that said light propagates by internal reflection from said first pair of outer surfaces through said light guide in the direction of propagation of the first component in the plane, and (b) wherein in each of said sets of faces, the corresponding faces are oriented to refract a part of said light directed by internal reflection of said light guide to propagate along said light guide in the direction of propagation of the second component in a plane not parallel to said first component in planes.

According to another feature of one embodiment of the present invention, said input device is a second light guide including: (a) a second pair of outer surfaces parallel to one another, and (b) a set of facets.

In accordance with another distinctive feature of one of the embodiments of the present invention, in at least one of the mentioned sets of faces, the distance between each of the mentioned partially reflecting faces is made such that in the field of view of the image reflected by the mentioned one of the mentioned sets of faces, the step with which double reflection propagates along said fiber, did not coincide with the integer value of said distance.

According to another feature of one of the embodiments of the present invention, the first angle of said partially reflective faces in the first set of said at least two sets of faces is different from the second angle of said partially reflective faces in the second set of said at least two sets of faces, wherein said angles are given relative to said first pair of outer surfaces.

According to another feature of one of the embodiments of the present invention, the first angle of said partially reflective faces in the first set of said at least two sets of faces is substantially the same as the second angle of said partially reflective faces in the second set of said at least two sets of faces, wherein said angles are given relative to said first pair of outer surfaces, and said first set is rotated relative to said second set.

In accordance with another aspect of one embodiment of the present invention, there is also provided (a) a light source for introducing illumination into said light guide, and (b) an image modulator reflecting the propagated light generated by said light guide from said introduced illumination, wherein the reflection produces reflected image light that crosses said light guide.

In accordance with the ideas of one of the embodiments of the present invention, a method for manufacturing an optical device is provided, wherein said optical device comprises a light guide having: (i) at least two sets of faces between a first pair of outer surfaces, (ii) said outer surfaces are parallel to one another , (iii) each of said sets of faces contains a plurality of partially reflecting faces parallel to one another, and in each of said sets of faces, said corresponding faces are located: at an oblique angle with respect to said first pair of outer surfaces, and not parallel with respect to the other of said sets faces, wherein the method includes: (a) providing a first array of partially reflective faces, (b) providing a second array of partially reflective faces, and (c) optically connecting said first array and said second array so that the faces of said first array and facets said second array were at an oblique angle with respect to said first pair of outer surfaces, and were not parallel to one another.

According to another feature of one of the embodiments of the present invention, said optical connection is made by pressing one against the other said first and second arrays with a mastic-like adhesive between said first and second arrays.

In accordance with another feature of one embodiment of the present invention, the first angle of said partially reflective faces in said first array is different from the second angle of said partially reflective faces in said second array, wherein said angles are given relative to the respective outer surfaces of said arrays.

According to another feature of one of the embodiments of the present invention, the first angle of said partially reflective faces in said first array is substantially the same as the second angle of said partially reflective faces in said second array, wherein said angles are given relative to the respective outer surfaces of said arrays, and said first array is rotated with respect to said second array before the optical connection of said arrays.

Also in accordance with the teachings of one of the embodiments of the present invention, there is provided a method for manufacturing an optical device that comprises a light guide having: (i) at least two sets of edges between a first pair of outer surfaces, (ii) said outer surfaces are parallel to one another, (iii) ) each of said sets of faces contains a plurality of partially reflecting faces parallel to one another, and in each of said sets of faces, said corresponding faces are located at an oblique angle relative to said first pair of outer surfaces, and not parallel to the other of said sets of faces, while said method includes: (a) providing a plurality of transparent flat windows having partially reflective surfaces; (b) optically connecting said windows to each other so as to form a first package, (c) cutting said first package to form a plurality of first flat arrays, wherein said cutting is performed through a plurality of said windows and at an oblique angle relative to at least two pairs of opposite sides of said first stack, (d) optically interconnecting a plurality of said first flat arrays so as to form a stack of arrays, and (e) cutting said stack of arrays to form at least one said fiber, wherein said cutting is performed through a plurality of said first flat arrays and at an oblique angle with respect to at least two pairs of opposite sides of said stack of arrays.

According to another feature of one embodiment of the present invention, said first planar arrays are polished and coated before the optical connection to form said array stack.

Also in accordance with the ideas of one of the embodiments of the present invention, there is provided a method for expanding an optical aperture in two dimensions by obtaining an image by introducing light into the above optical device.

Brief description of the figures

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying figures, in which:

Fig. 1 is an exemplary schematic diagram illustrating the effect of beam broadening in a light guide having two overlapping sets of partially reflective inner facets;

Fig. 2 is a schematic representation of an exemplary embodiment of a light guide;

Fig. 3 is a side view of a scheme for the propagation of light in a light guide;

Fig. 4 is a plot of reflectivity versus angle for various coatings having different reflectivity ranges;

Fig. 5 - geometric optical properties of the light guide depending on the angular position;

Fig. 6 - angular arrangement of the faces of the light guide;

Fig. 7 - geometric optical properties of the second set of faces;

Fig. 8 is a diagram of the angular arrangement of faces and boundaries of coatings in an alternative embodiment;

Fig. 9 shows another embodiment of the light guide, in which parts of the first section and the second section overlap along the thickness of the light guide to form a single-section light guide having intersecting edges;

Fig. 10 - a method for the production of a two-section light guide;

Fig. 11 is an exemplary method for manufacturing a single-section light guide;

Fig. 12A - lighting from the sides;

Fig. 12V - lighting from above, this version reduces the darkening of the side peripheral view;

Fig. 12C - lighting from the center (between two light guides), where the hardware parts of the projectors (right and left) can be combined to reduce size and weight;

Fig. 12D - lighting from above, which provides an almost complete peripheral unobscured view;

Fig. 12E - illumination at an angle below the location of the eye;

Fig. 13 is a variant of the structures shown above;

Fig. 14A and FIG. 14B are schematic representations of a light guide arrangement using the construction shown in FIG. thirteen;

Fig. 15 is a schematic representation of the propagation of light in a light guide;

Fig. 16A is a plot of the reflectivity (reflective profile) of a facet coating designed to reflect light rays incident at a high angle;

Fig. 16B shows the angular arrangement of the structure in the exemplary solution;

Fig. 17 is a schematic representation of the light propagation of an inverted image;

Fig. 18A is a schematic representation of the directions of reflections during the propagation of light rays in the light guide 173;

Fig. 18B is a schematic front view of a combined light guide 173 in which three facet sections are combined;

Fig. 18C is a schematic representation of the directions of reflections during the propagation of light rays in the light guide 173 in another embodiment of the three facet sections;

Fig. 19A is a pie chart of an alternative direction for introducing light into the light guide;

Fig. 19B is a schematic view of a light guide using the circle pattern shown in FIG. 19A;

Fig. 19C is a diagram of the propagation of rays in the said light guide;

Fig. 20 is a circle diagram of an alternative embodiment with facets on the other side of the image;

Fig. 21 shows a hybrid system in which reflective facets are combined with diffraction gratings;

Fig. 22A - sections separated by a coating with partial reflection;

Fig. 22V - alternative compact optical device;

Fig. 22C - an alternative version with a translucent reflector;

Fig. 23 is a schematic representation of the propagation of light in a light guide with a non-optimal expansion;

Fig. 24A are exemplary two identical intersecting facet sections having a connecting prism used to introduce the input beam into the light guide;

Fig. 24B shows an embodiment in which the light guide is polished at an angle and a prism is attached to the polished plane from above;

Fig. 24C - version with prism attached to the vertical end of the light guide;

Fig. 24D illustrates the combination of a prism with an image generator using a polarizing beam splitter;

Fig. 25 - safety connecting element between sections;

Fig. 26A and FIG. 26B are side and front views, respectively, of a two-dimensional (2D) light guide providing entry into a two-section light guide;

Fig. 27A and FIG. 27B are side and front views, respectively, of a one-dimensional (1D) light guide with an insertion into a two-section light guide;

Fig. 28 is a pie chart of an unwanted image overlapping a virtual image;

Fig. 29A - a visor that prevents light falling at a large angle from entering the light guide;

On FIG. 29B shows a coating with angle dependent properties to prevent high angle light from entering the fiber;

Fig. 30 - alternative arrangement of sections;

Fig. 31 is a side view of an exemplary light guide optical element (LOE) configured for use in said embodiment;

Fig. 32A is a schematic side view of an exemplary lighting system;

in FIG. 32B is a schematic front view of an exemplary lighting system.

A detailed description of the first embodiment of the present invention shown in FIG. 1-32V

The constituent parts and operation of the system in accordance with the present embodiment of the present invention can be better understood with reference to the figures and their accompanying description. The present invention is a system for expanding an optical aperture. In general, a small aperture image projector projects an input beam that is expanded by a light guide having more than one set of parallel partially reflective surfaces, or "facets", preferably having optimized coatings. Alternative versions use a combination of facets and diffractive elements. This reduces the need to expand the aperture beyond the transparent fiber, and reduces the size and weight of the system.

The optical device includes a light guide having a first pair of outer surfaces parallel to one another and at least two sets of faces. Each of the sets includes a plurality of partially reflective faces, parallel to each other, located between the first pair of outer surfaces. In each of the face sets, the corresponding faces are at an oblique angle with respect to the first pair of outer surfaces and are non-parallel with respect to the other of the face sets.

On FIG. 31 is a side view of an exemplary light guide optical element (LOE) 903 configured for use in the above embodiment. The first reflective surface 916 is illuminated by an incoming directional light beam 4 (input beam) emanating from the light source 2. In the context of the present description, the light source 2 is also referred to as a "projector". For clarity, the accompanying figures generally show only one light beam, the incoming light beam, incoming beam 4, also referred to as "beam" or "incoming beam". In general, wherever an image is represented herein by a light beam, it should be noted that a beam is a discrete image beam, usually formed by a plurality of divergent beams, each corresponding to a dot or pixel in the image. With the exception of the specific designation of the edge of the image, the depicted beams usually represent the midpoint of the image. In other words, the light corresponds to the image, and the center ray is the center ray from the center of the image or the center pixel of the image.

The first zone 954 is close to the input beam 4 where the image illumination is introduced into the light guide 920. The reflective surface 916 at least partially reflects the incident light of the input beam 4 from the source 2 such that the light is captured within the light guide 920 by internal reflection, typically total internal reflection. reflection (TIR). The light guide 920 is typically a transparent substrate, and is referred to as "flat substrate", "light-transmitting substrate", and waveguide. Light guide 920 includes at least two (main, outer) surfaces, typically parallel to one another, shown in the figure as back (main) surface 926 and front (main) surface 926A. It should be noted that the designations "front" and "rear" in relation to the main surfaces (926, 926A) are given for ease of reference. Input to the light guide 920 may be through various surfaces such as front, back, side edges, or any other desired input surface.

The input beam 4 enters the fiber substrate at the near end of the substrate (right side of the figure). Light propagates through the light guide 920 and one or more edges, usually through at least a plurality of edges and usually through several edges, towards the distal end of the light guide 920 (left side of the figure). The light guide 920 typically guides rays of propagating light into the substrate via internal reflection from outer surfaces.

Optionally, upon reflection from the interior surfaces of the substrate 920, the trapped waves reach a set of selectively reflective surfaces (facets) 922 that project light from the substrate into the viewer's eye 10. In the above exemplary figure, the captured beam is sequentially output from the substrate 920 by two different partially reflective surfaces 922 at points 944.

Internal partially reflective surfaces, such as a set of selectively reflective surfaces 922, are generally referred to as "edges" in the context of the present description. For augmented reality applications, the facets are partially reflective, allowing light from the environment to pass through the front surface 926A, pass through the facet-containing substrate, and exit the backing surface 926 into the viewer's eye 10. Exemplary beam 942 shows light from input beam 4 partially reflected from reflective surface 916, and exemplary beam 941 shows light from input beam 4 partially transmitted through reflective surface 916.

Internal partially reflective surfaces 922 generally at least partially intersect light guide 920 at an oblique angle (i.e., non-parallel—neither parallel nor perpendicular) to the direction of extension of light guide 920. Partial reflection may be accomplished by a variety of techniques, including but not limited to , transmitting part of the light or using polarization.

The light guide 920 optionally has a second pair of outer surfaces (not shown in said side view) parallel to each other and non-parallel to the first pair of outer surfaces. In some embodiments, the second pair of outer surfaces is perpendicular to the first pair of outer surfaces. Usually, each of the faces is located at an oblique angle to the second pair of outer surfaces. In other cases where reflections from the outer surfaces of the fiber are not desired, said outer surfaces are generally left unpolished and/or coated with a light absorbing (eg black) coating to minimize unwanted reflections.

On FIG. 1 is an exemplary schematic diagram illustrating the effect of beam expansion in a light guide 3 comprising two overlapping, differently directed sets of partially reflective inner facets, in which the beam propagates in two ways with the facets within the light guide 3. The projector 2 projects an image into the light guide 3 as of the incoming beam 4. One set of facets (the first set of faces shown in the attached figures) continuously deflects part of the input beam (projected image) 4 into the first guided beams (projected image) 6. In accordance with some most preferred embodiments, this set of first faces is located at an angle such that both the incident image beams of the incoming beam 4 and the reflected image beams of the first guided beams 6 are within the ranges of angles that are captured by the internal reflection on the major surfaces of the substrate (external surfaces) of the light guide 3 and hence are guided by the light guide (also called "substrate" or "waveguide") of the light guide 3. More preferably, in terms of overlapping with the first set of edges, is another second set of edges embedded in the same light guide at an angle different from the angle of the first set of edges. The second set of facets deflects part of the first guided beams 6 (projected image) into the second guided beams 8 (projected image) 8. The second guided beams 8 are output from the light guide 3 typically into the eye 10 of the observer.

On FIG. 2 shows a schematic representation of an exemplary embodiment of the light guide 3. In the first group of non-limiting designs, the light guide 3 comprises two layers with different arrangements of inner faces. Each of the first section 14 and the second section 12 may be a LOE 903 as described above. Therefore, the first and second sections are referred to in the context of the present description as the first and second LOE, or the first and second layers, or the first and second facet sections, respectively. Each section contains a corresponding set of faces. The first section 14 contains the first set of 32 faces, and the second section 12 contains the second set of 36 faces. The first and second sections (14, 12) are deployed in accordance with the overlap with respect to the viewing direction of the user (user's eye 10). In this example, the second layer 12 overlaps the first layer 14 to form a matrix of overlapping faces at the output of the light guide 16. It should be noted that the orientations depicted in the accompanying figure are shown simply and schematically for ease of description. Because the light guide 16 has at least two sets of edges that at least partially overlap in the user's viewing direction, the light guide 16 is also referred to as an "overlapping light guide".

Each set of faces provides visibility to a specific area of the placement of the section containing the set of faces. At least the first set of faces provides constant visibility when viewed in the viewing direction of the corresponding area of the first set of faces. The area for placing a set of faces includes the area (space) between the faces. The preferred facet configuration can be represented by extrapolating the lines of intersection of the facets with the fiber surface. If there is a first set of intersection lines between the planes of the first set of faces with the plane of the outer surface and if there is a second set of lines of intersection between the planes of the second set of faces with the same plane (the outer surface of the light guide), the first and second sets of lines are non-parallel.

Consideration of factors to determine facet orientations in these layers is described below. It should be noted that in Fig. 1 initially shows the light guide 3 in a general view, and FIG. 2 shows a light guide 16 with internal structure elements (first and second sections). A light guide 16 with two sets of (parallel) facets can be characterized as having "two axes" and a light guide with an arbitrary number of sets of edges (more than one) can be characterized as a "multi-axis" light guide. In this context, each "axis" is the beam expansion direction in the light guide 3, the direction in the light guide 3 in which the array of facets is located.

On FIG. 3 shows a side view of the light guide pattern 16. First layer 14 includes a first set of edges 32 (also referred to as first section edges or first edges). Likewise, second layer 12 includes a second set of facets 36 (also referred to as second section faces or second faces). The light guide 16 has a thickness of 16T between the first outer face (surface) 22 and the second outer face (surface) 24 (respectively, similarly between the rear surface 926 and the front surface 926A). Typically, the first layer 14 and the second layer 12 are optically coupled so that light passes between these layers without being reflected. The direction of the light internal in each layer is achieved by internal reflection, usually by means of a total internal reflection (TIR) mechanism, from the outer edges of the light guide 16. In this figure, the projector 2 is made using an optical device 20. The prism 16P is part of the light guide input device 16 Optical device 20 illuminates light guide 16 with an input image (input beam 4) collimated to infinity (eg as described in WO 2015/162611 by LUMUS Ltd.). When light 5 propagates inside the light guide 3, the propagating light 5 is internally reflected from the first outer face 22 and the second outer face 24 of the light guide 16. The first outer face 22 and the second outer face 24 of the light guide 16 shown in the accompanying figure are respectively similar to those shown in FIG. 31 front face 926A and back face 926 LOE 903.

The first section 14 of the light guide 16 includes the inner edges reflecting the propagating light 5 in the transverse direction (change of direction not shown in the side view in the attached figure) as the first guided beams 6. The second section 12 includes the edges reflecting the propagating light 4A as the second directed beams 8 in the direction of the eye 10 of the observer. The edges in each section preferably overlap (as defined in LUMUS Ltd.'s patent application PCT/IL2018/050025, which is incorporated herein in its entirety) and light in the direction of the viewer's eye 10 passes through more than one edge in each sequence of faces to improve the uniformity of the illumination of the image.

The light is directed into the light guide 16, typically by means of an input device such as an optical device 20 and a prism 16P. The input device and/or the image projector is designed to direct light into the light guide 16 so that the propagating light 5 propagates by internal reflection from the outer surfaces (22, 24) along the light guide 16 in the direction of propagation with the first component in the plane. (The out-of-plane component changes direction with each internal reflection from the main outer surfaces of the fiber). At least the first set of facets 32 is directed to deflect a portion of the light guided by the internal reflection of the light guide 16 to propagate through the light guide 16 with a propagation direction with a second in-plane component not parallel to the first in-plane component. This redirection of the image light by partial reflection in the facet sequence results in an increase in the aperture in the first dimension within the light guide. The output device is typically designed to output at least a portion of the light propagating with the second component in the plane. The output device is typically a second (or third) set of partially reflective facets 36 resulting in an additional increase in the aperture in the second in-plane direction.

The second section 12 (with exit edges) is preferably closer to the observer's eye 10, so will not obstruct the outgoing light (the second directional beam 8), although the reversed embodiment is also included in the scope of the present invention, and may be preferred in some applications of the present invention.

In this description, an embodiment of the light guide 16 is considered, which uses glass having a refractive index of 1.5955, and which outputs (transmits) a rectangular image with an opening angle of 40 degrees.

On FIG. 4 shows a plot of reflectivity versus angle for various coatings having different reflectivity ranges. Preferably, the coating of the facets should be done so as to obtain maximum efficiency and minimum energy associated with spurious images. In preferred embodiments of the present invention, image reflection occurs at angles of incidence of 0-55 degrees from normal to the surface, and the coating is substantially transparent at angles of incidence of 55-87 degrees (except for the highly reflective coating, which is transparent up to 72 degrees) from the normal to the surface. These characteristics of the coatings determine the angle of inclination of the face. This characteristic of the coatings is almost the same across the entire visible spectrum, hence a single light guide will transmit all colors (commonly referred to as RGB, or red, green and blue). Edges that are at a greater distance (toward the far end of the light guide) from the entry of light into the light guide (proximal end of the light guide) are preferably provided with higher reflectivity coatings.

On FIG. 5 shows the geometrical optical properties of the light guide 16 depending on the angular position. The critical angle limits TIR of both outer surfaces (first outer surface 22 and second outer surface 24) are represented as circles A30, where rays directed inside these circles will exit the substrate, and rays directed outside these circles will remain trapped inside substrates. The image light introduced into the light guide 16, the input beam 4, has a rectangular angular distribution. The input beam 4 is reflected back and forth between the outer surfaces (the first outer surface 22 and the second outer surface 24) and is shown as squares 4L and 4R (conjugated images reflected by the main surfaces of the substrate, which is equivalent to the input beam 4 shown in Fig. 1).

On FIG. 6 shows the orientation of the facets of the light guide 16. The input image light beam 4 first encounters the first set of facets 32 of the first section 14 of the light guide 16. The orientation of the first set of facets 32 is shown as a plane indicated by circle A32. These faces 32 of the first section have a coating having an angular reflectivity as shown in FIG. 4. The angle at which the coating is transparent (55 degrees in this example) is indicated by circles A34. Therefore, any image shown (outside) between these circles (i.e., with angles greater than 55 degrees relative to the face normal, such as 4L in the accompanying figure) will pass through the coated face with minimal reflection. Images that fall within these circles (i.e., with angles less than 55 degrees from the normal to these faces, such as 4R in the attached figure) will be partially reflected. The reflection angle will be inverse of the A32 face angle. Therefore, the 4R image is reflected (as indicated by arrow 600) to generate a conjugate 6L image (which corresponds to the first directed beams 6). As the image propagates in the light guide 16, some of the light will be reflected back and forth between 4R and 6L, thereby improving the illumination uniformity of the final image.

On FIG. 7 shows the geometric optical properties of the second set of facets 36. Image light 6L is reflected from the outer surfaces (22, 24) of light guide 16 to generate a conjugate image 6R. The images 6L and 6R propagate by reflecting off said surfaces (22, 24) and meeting faces (faces 36 of the second section) of the second section 12, for which the orientation is indicated as A36 in this description. The coating on the edges 36 of the second section also has a transparent range (as A34 in Fig. 6), and the boundaries of the transparent range are shown as circles A38.

The images 6L, 4L and 4R are within the transparent range (between the circles A38) and therefore will not be significantly reflected by the second faces 36 of the second section 12. However, the image 6R is within 55 degrees and therefore will be partially reflected by the second facets 36 falling within the range of angles based on the internal reflection of the main surfaces of the substrate, and is displayed (as shown by arrow 700) outside the light guide 16 in the form of an image 8 (second guided beams 8) in the direction of the eye 10 of the observer.

On FIG. 8 shows a diagram of the angle of dissolution of an alternative facet design and facet coverage. The images 4L and 4R are not reflected by the second faces 36 of the second section 12 (within the boundary A38 representing an angle of >55 degrees). In this case, the images 4L and 6R are not reflected by the first faces 32 of the first section 14 (within the boundaries of A34).

In the exemplary embodiment, assuming that the first image input to the light guide 16 is a 4L image, the images are combined in the following order:

1. Image 4L: is introduced into the light guide 16 by the optical system 20 of the projector.

2. 4R image: generated as conjugate to the 4L image by internal reflection in the light guide 16.

3. Image 6L: generated by reflecting the image 4R with the first faces 32.

4. Image 6R: generated as conjugate to the image 6L by internal reflection in the light guide 16.

5. Image 8: generated by reflecting the image 6R with the second faces 36.

Various angulations may be used having the same basic connection properties of the same sequence of images as described above. It should be noted that both the incoming 4R images hitting the first faces 32 and the 6L reflected images coming from the second faces 36 are within the reflection angles of the inner major surfaces [outer surfaces (22, 24)] of the substrate, and are therefore guided by the substrate. . The internal reflection through the outer surfaces (22, 24) of the light guide 16 is similar to the internal reflection through the main surfaces (926, 926A) of the substrate 920 LOE 903.

Although the preferred embodiments of the present invention shown in this specification are designed to optimize the angles of each image with respect to each facet so that the images are selectively partially reflected or transmitted with minimal reflection according to the angle-dependent selective properties of the facet coatings, it should be noted that such optimization is not necessary. In some cases, it may be acceptable to use non-optimized angles and/or non-optimized coverages that result in the generation of various unwanted modes (corresponding to spurious images), provided that the spurious images are either relatively low energy modes or fall outside the field of view of the desired output. Images.

On FIG. 9 shows another embodiment of the light guide 16, where portions of the first section 14 and the second section 12 overlap through the thickness of the light guide to form a single section light guide 40 with intersecting edges. In other words, the sets of faces, in this case the first set of faces 32 and the second set of faces 36, overlap and form (create) an array in the same plane of the light guide. The single-section light guide 40 has a thickness of 40T between the first outer surface 22 and the second outer surface 24. A method for producing such a light guide is described below. The angles of the edges in the single-section light guide 40 are similar to those described above for the two-section light guide 16 shown in FIG. 4 and FIG. eight.

On FIG. 10 as well as FIG. 2 and FIG. 3, a method for manufacturing a two-section light guide 16 is shown. The windows 50 of the first first set are coated, stacked, and sealed together to form the first stack 51. In this context, the term "window" refers to a transparent flat plate. The first stack 51 is cut at an angle to form a first array of reflective surfaces 52. Similarly, windows 54 of a second set (a different set than the first set of windows 50) are coated, stacked, and bonded together to form a second stack 55. Second the stack 55 is cut at a second angle (another angle than that used to cut the first stack 51) to form a second array of reflective surfaces 56. The two arrays (the first array 52 and the second array 56) are joined together 60 at an appropriate relative angle (e.g., fastened or glued together at a given angle). The overlapping arrays are trimmed 61 to shape the light guide 16. In some embodiments, optional coatings 62 are bonded as the outer surfaces of the finished two-piece light guide 64. Each step may include the optional cutting, grinding, and polishing of one or more surfaces. More than one array can be made from each package according to the actual size of the windows and the desired size of the fiber 64.

Significant cost savings can be achieved by using the same arrays (face plates) for both sections of the light guide 16. For example, BK7 glass is used to obtain two arrays (first array 52), each of which has edges located at an angle of 26 degrees. This is different from the above description of the production of two arrays (the first array 52 and the second array 56, each of which has faces located at different angles). The two arrays are then joined at 60 with a rotation of 115 degrees from one another. This exemplary layout allows an image having 38 degrees with a 16:9 field ratio to be transmitted.

On FIG. 11 shows an exemplary method for manufacturing a single-section light guide 40. Similar to that shown in FIG. 10 for the production method of the two-section light guide 16, the windows 50 of the first set are coated and stacked to form the first package 51. The package is cut into a plurality of first arrays 52. The slices of the first array 52 are ground, coated and stacked to form the package 70 arrays. This array package 70 may be similar to the first package 51, however, in this case, the array package 70 has additional coated layers. The array stack 70 is now cut to produce slices of the array 71 having two sets of parallel faces within the same light guide. Optionally, outer windows 62 may be added to provide a complete single-section light guide 72 (single-section light guide 40 shown in FIG. 9). The angles of each cut and the angles of each stacking can be the same or different from each other and are determined by the requirements for the finished light guide 16.

On FIG. 12A-12E show various exemplary lighting designs using projectors 2 to illuminate light guide 16. FIG. 12A shows illumination from the sides. The illumination spread, indicated by arrows 800A1 and 800A2, shows the most downward expansion, and part of the expansion is upward caused by cross-feedback from 6L to 4R (see FIG. 6).

On FIG. 12B shows illumination from above, this embodiment reduces shadowing of the peripheral field of view.

On FIG. 12C shows illumination from the center (between two light guides) where the projector hardware (right and left) can be combined to reduce size and weight.

On FIG. 12D shows illumination from above, which provides an almost complete unobscured peripheral field of view.

On FIG. 12E shows illumination at an angle below the position of the eye. In this way, the image projector is positioned outside the peripheral field of view for convenience.

On FIG. 13 shows variants of the structures described above. Options include various facet and image angles. Compare the attached figure with Fig. 8. In the accompanying figure, the corner A32 of the first set of facets 32 is such that the corner A32 is located on the opposite side of the corners of the image 6R, thereby providing a larger image. Circles A39 show the internal reflection angles of the two outer surfaces where an image projected within these circles would exit the light guide. For example, image 8 is displayed outside of the circles and will be reflected inside the light guide as a conjugate image, where the image conjugation is the image reflected from the outside of the light guide. Multiple reflections from the outer edges along the fiber create two conjugated images.

On FIG. 14A and FIG. 14B shows schematic representations of the location of the light guide using the structures shown in FIG. 13. In FIG. 14A shows a projector 2 that inputs image light into a light guide 16. The width of the input light is determined by the aperture of the projector. The two arrows indicate the width of the projected light beams 100 (4L and/or 4R in FIG. 13) for a particular point in the field of view (ie, in a particular direction). Preferably, this description refers to the center of the field of the projected image. Facets 102 (shown as orientation A32 in Fig. 13) reflect light in vertical directions 104 and 106. Vertical reflection 104 and vertical reflection 106 have the same direction (6R and/or 6L in Fig. 13) but different locations along beam 100. Obviously, vertical reflection beams 104 are reflected by three facets 102, while vertical reflection beams 106 are reflected by only two facets 102. Therefore, the reflected image will not have a uniform intensity distribution.

On FIG. 14B, facets 109 are arranged such that along the reflection directions (reflection direction 108 and reflection direction 110) there will be a constant number of reflections (two in this case) from the injected beam 100. The number of facets in facets 109 made for reflection may be one , two or more faces. The geometric criteria for obtaining a given number of facets contributing to the reflected beam are determined by the distance between the facets, the angle of the facets relative to the beam of the projected image, and the width of the aperture using simple trigonometry.

The second set of edges 36 of the second section 12 (see FIG. 3 and angle A36 in FIG. 13) preferably overlap to improve image uniformity.

On FIG. 15 shows a schematic representation of the propagation of light within the light guide 16. The required size of the combined light guide is determined by the direction of light propagation within the light guide and in open space in the direction of the observer's eye. In the accompanying figure, guided light propagation is shown with dotted lines, and light propagation in open space is shown with solid lines. Both propagations of light are not in the same plane, but are shown schematically in the same plane in the attached figure for clarity. For clarity, the change in the angle during refraction is also not shown.

The projector 2 inputs an image having a field width (different beam angles). The boundaries of this field are represented by beams 115 and 116 (size 4R in Fig. 13). Beams 115 and 116 are reflected at points 118 by first faces 32 (angle A32 in FIG. 13) into beams 117A and 117B in the other direction (downward in the accompanying figure, 6L in FIG. 13).

The two beams 117A and 117B propagate other distances in a new direction before being reflected at points 120 by second faces 36 (angle A36 in FIG. 13) in directions 122 (originally 116) and 124 (originally 115) into the viewer's eye 10.

Obviously, the height 126 of the light guide 16 cannot be less than the expansion 115 with 116 and 122 with 124

In the embodiment shown, the second exit edges 36 (corner A36 in FIG. 13) will only start at the top point 120 (as shown in the accompanying figure). The second faces 36 should not be higher than the top point 120, because the observer (observer's eye 10) will not see the entire projected field.

On FIG. 16A, FIG. 16B and FIG. 17 shows an approach that also makes it possible to reduce the height of the fiber compared to the embodiments described above.

On FIG. 16A is a plot of the reflectance (reflective profile) of a facet coating designed to reflect light rays incident at a high angle (compared to the reflectances shown in FIG. 4). This reflective profile is used to reverse the propagation angle of the light beam when the propagating light exits the light guide.

On FIG. 16B shows an angled design of an exemplary approach mentioned. The image enters as 130L, exits 1600 through the outer surface at 130R, then the angle of the bevels A132 (from the set of bezels A132 described below) coated as shown in FIG. 16A, an image is output 1602 to 134R. The outer facet then reflects 1604 the propagating light as an image 134L reflected 1606 by the angle of the similarly coated facets A136 (from the set of facets 136 described below) from the light guide to the viewer as an inverted image 138. Obviously, the bottom of the image 130L and 130R becomes the top part of the inverted image 138, i. e. the image is inverted.

On FIG. 17 shows a schematic representation of the light propagation of an inverted image 138. Projector 2 inputs an image having a field of view defined by beams 140 and 142 (angles 130L and/or 130R). Reflection at points 144 is carried out by a set of faces 132 into the corresponding rays 146 and 148 (images 134L and/or 134R). Reflection points 150 represent reflection by a set of facets 136 into respective beams 152 and 154. Obviously, the direction in the vertical plane of beams 152 and 154 is opposite to that of beams 140 and 142. Therefore, the overall height 156 of the light guide is less than height 126 in FIG. fifteen.

On FIG. 18A, FIG. 18B and FIG. 18C shows another embodiment of the present invention in which three sets of facets are combined to form a light guide 16. FIG. 18A is a schematic representation of the reflection directions of the propagation of light rays in the light guide 173. FIG. 18B is a schematic front view of a combined light guide 173 in which three facet sections are combined. Facet set 174 has a predetermined orientation different from facets 176 and different from output faces 178. Projector 2 inserts beam 180 into light guide 173. At point 182, facet set 174 partially reflects beam 180 in direction 184. It should be noted that all points represent processes reflections (through the corresponding sets of faces) distributed along the fiber. At some point 186, the propagating beam 184 is reflected by one of the sets of edges 174 in the direction of the original beam 180. At point 191, the beam is output by the set of edges 178 as a beam 193 in the direction of the eye 10 of the observer. Another expansion path is created by edges 176. The beam from projector 2 is reflected at point 187 by a set of edges 176 in direction 188. At some point 190, beam 188 is reflected back in direction 180 and at point 192 is output by a set of edges 178 as a beam 195 in the direction of the observer's eye 10 .

On FIG. 18C shows a schematic representation of the directions of reflections of propagation of light rays in the light guide 173 in yet another embodiment of the three facet sections. The attached figure shows another way of combining three facet sections into a single fiber to obtain an aperture extension.

On FIG. 19A shows a circle diagram of an alternative direction for introducing light into a light guide. In general, it is possible to introduce the light rays of the input image into any of the conjugated propagating images to obtain an aperture expansion. For example, the angle diagram shown in FIG. 8 may be modified in the accompanying figure to introduce 1900 image illumination into 6L or 6R (where the images are reflected 1902 as conjugate images). Light is also reflected back and forth 1908 to 4L, i.e. mates 1906 with 4R. These images propagate in the other direction (thereby expanding the distribution of rays in the light guide) until 1908 returns to the original direction, and finally outputs 1904 at 8, as shown in the accompanying figure.

On FIG. 19B shows a schematic representation of a light guide using the angle diagram shown in FIG. 19A. The image projector 2 inputs an image into a combination of diagonal edges 202 (shown diagonally in the attached figure, operating similarly to the first set of edges 32) and connecting edges 203 (drawn vertically in the attached figure, operating similarly to the second set of edges 36).

On FIG. 19C shows a diagram of beam propagation in said light guide. In the accompanying figure, dashed lines 1920 show the injected beam (equivalent to 6R and 6L) from image projector 2. Dash-dotted lines 1922 show the beams as they propagate laterally to widen the aperture (equivalent to 4R and 4L). Solid arrows 1924 show the outgoing beam (equivalent to 8). It should be noted that when using the above embodiment, the input of the image into the fiber in the form of images 6R or 6L is carried out at a steeper angle (shown as the angle of these images relative to the plane of internal reflection A39) relative to the images 4R and 4L. Therefore, to obtain filling along the thickness of the light guide, a smaller aperture of the projector is sufficient.

On FIG. 20 shows an angle diagram of an alternative embodiment of the present invention with facets on the other side of the image. In said diagram, the second set of faces 36 is on the other side of the image 6L (ie, both 6L and 6R are on the same side of the second set of faces 36). Double lines (1930A, 1930B) are an alternative for introducing an image into the light guide. The image is entered as 6L, 6R, 4L or 4R. Similar to previous embodiments of the present invention, the 4R and 4L images are conjugated 1936 images that are output 1938 back and forth to 6L, which conjugates 1932 to 6R. Image 6R is also reflected 1934 as image 8 in the direction of the observer.

In alternative embodiments of the present invention, various embodiments can be used to reflect faces, including:

images and conjugated images from different sides of the face (Fig. 13);

images and conjugated images on one side of the face (Fig. 20).

In alternative embodiments of the present invention, various coatings may be used, including:

reflection of the image at an angle close to the angle of the face (Fig. 16A);

reflection of the image at an angle different from the angle of the face (Fig. 4).

In alternative embodiments of the present invention, various options for introducing an image into a light guide can be used, including:

direction directly to the terminal (6R, 6L in Fig. 20);

the direction should be changed before withdrawal (4L, 4R in Fig. 20).

On FIG. 21 shows a hybrid system in which refractive edges are combined with diffraction gratings to enable aperture expansion in much the same way as shown in FIG. 1 and FIG. 2.

The use of diffraction gratings requires the use of at least two gratings with polar optical refraction so that chromatic dispersion can be neutralized. In the embodiment of the present invention shown in the accompanying figure, a diffraction grating 210 is used to input light into the light guide, while a diffraction grating 212 is used to output light from the light guide. The lateral expansion of the aperture is achieved by overlapping the diagonal facets 214 which output transversely propagating back and forth light without introducing chromatic aberration. In this case, a set of overlapping diagonal faces 214 is deployed to redirect the first guided mode (internal reflection at the major surfaces of the substrate) to the second directional mode (internal reflection at the major surfaces of the substrate).

On FIG. 22A-22C show various embodiments of the present invention for beam mixing during propagation. Mixing of the propagating beams within the light guide 16 can be achieved by various designs. For example, by introducing a partial reflection between the first set of faces 32 in the first section 14 and the second set of faces 36 in the second section 12.

On FIG. 22A shows sections separated by a partially reflective coating. The first section 14 and the second section 12 are separated along the contact surface 250 by a partially reflective coating. The input optical device 20 delivers the input beam 4 to the light guide 16. The contact surface 250, and hence the partially reflective coating, are parallel to the outer surfaces (first outer surface 22 and second outer surface 24). In this design, all beams will be kept in the original directions of the propagating light beams 5 (shown by dark arrows), despite multiple separations and reflections of the propagating beams 5. For clarity, the attached figure shows the division of only one beam. From this description, one skilled in the art will appreciate that the multiple splits that occur also improve the uniformity of the output image.

Alternatively, the first section 14 and the second section 12 may be made of different materials (e.g., glass and plastics or different types of glass), thereby causing Fresnel reflections on the contact surface 250. The contact surface 250 may alternatively and/or additionally induce polarization rotation (this effect will be caused by a dielectric change at the contact surface), which will also improve the uniformity of the output image.

On FIG. 22B shows an alternative 20V compact optical device. The cost of the system can be reduced by downsizing the image projector (optics 20 in FIG. 22A). However, uniform illumination of the image requires illumination of the entire entrance of the light guide 16 by the image projector. In the accompanying figure, the increased mating caused by the reflective surface of the contact 250 allows the compact image projector 252 for the optical device 20B to be used with smaller dimensions compared to the optical device 20.

On FIG. 22C shows an alternative embodiment of the present invention with a partial reflector. Maintaining parallel contact surface 250 with the outer surfaces (first outer surface 22 and second outer surface 24) can be technically difficult. The attached figure shows a small parallel reflector 254 in use. The small parallel reflector 254 is configured as a contact surface 250 only in part of the contact surface between the first section 14 and the second section 12. This small reflector 254 separates the input combined beams (input beam 4) so that the entire light guide 16 is evenly illuminated. Preferably, the reflectivity of the small reflector 254 (contact surface 250) gradually decreases along the light guide (from the near to the far end), thereby improving the uniformity of the output image. This gradual decrease in the reflectivity of the top section (first section 14) can be used to compensate for the increased reflectivity of the edges (the edges further away from the projector are more reflective to maintain a constant image brightness), thereby creating the illusion of constant transparency through the light guide.

On FIG. 23 is a schematic representation of the propagation of light in a light guide with a non-optimal expansion. Aperture expansion in the transverse direction can be accomplished by creating non-optimal beams (also referred to as "spurious images") and feedback from these spurious images. However, this method is less efficient and may cause image degradation compared to the optimal beam propagation methods described above. This method is carried out using crossed faces (as shown in Fig. 2), but without coverage optimization (as shown in Fig. 8). Therefore, 4L and 4R are also reflected by the second set of facets 36, thereby creating unwanted images. However, if the facet angles are chosen correctly (designing with the method of successive approximations in the angle of dissolution, as shown in Fig. 8), these spurious images will be outside the observer's field of view.

The attached figure shows how these "spurious images" are used to expand the image in yet another transverse direction. The projector 2 injects beams in direction 260. After reflection by the first set of edges 32 of the first section 14, the propagating light is deflected in the direction 262. After reflection by the second set of edges 36 of the second section 12, the propagating light is deflected from the light guide in the direction 264. The previous expansion was carried out in one transverse direction. Incoming rays in direction 260 may also be reflected by the faces of second section 12 in direction 266, which is opposite to direction 264. Re-interaction with the second set of faces 36 of second section 12 reflects propagating rays from direction 266 back to original direction 260, but offset sideways. Similar to the above description of direction 260, the propagating beam in direction 260 is reflected by the first set of edges 32 in direction 262 and the second set of edges 36 is reflected from the fiber in direction 264.

On FIG. 24A shows exemplary two identical intersecting facet sections having a connecting prism 270 used to introduce input beam 4 into light guide 16. A single main beam 2400 (center of field and center of aperture) is shown as a beam shared by the facets of the sections. This input to the fiber can be made in various ways.

On FIG. 24B and FIG. 24C are schematic cross sections of input devices. The cross section is taken along the plane of the main beam 2400 shown in FIG. 24A.

On FIG. 24B shows an embodiment in which the light guide 16 is angled and the prism 2410 is attached to the top of the ground plane. This embodiment allows full reflection from the lower part (as shown in the figure) of the light guide 16.

On FIG. 24C shows an embodiment with a prism 2420 attached to the vertical end of the light guide 16. This embodiment allows for a longer connection section (extending from the rectangular shape of the light guide 16). This embodiment also allows the use of different refractive indices for the prism 2420 and for the light guide 16.

On FIG. 24D shows an embodiment integrating a prism and an image generator using a polarizing beam splitter. This version of the design allows you to reduce the dimensions.

Different facet arrangements within the two sections will result in a change in the polarization of the rays in the light guide 16. Therefore, it may be preferable to introduce unpolarized light. Unpolarized light can be obtained from a substantially unpolarized projector (eg based on TI DLP, "Texas Instruments Digital Light Processing") or by placing a depolarizer in front of a polarized projector (monocrystalline quartz waveguide window).

On FIG. 25 shows the safety link between the sections. In the event of a break in the light guide 16 (glass or plastic light guide), the fragments must remain connected together and maintain the integrity of the structure to avoid injury to the observer. This preservation of the integrity of the light guide can be achieved in various ways, for example, by introducing a suitable adhesive or plastic film between the two sections (between the first section 14 and the second section 12), shown in the attached figure as the intermediate layer 280. Therefore, in the event of the destruction of one or more sections , the resulting fragments will remain attached to the light guide 16 rather than dissipate, thereby reducing the chance of injury to the user. The optical properties of the interlayer 280 may vary, including, but not limited to, those discussed above with respect to the interface 250. The interlayer 280 may be matched in refractive index with the refractive index of the sections, or the refractive index of the intermediate layer 280 may be different from the refractive index of the sections. to obtain reflections, as shown in Fig. 22.

On FIG. 26A and FIG. 26B are side and front views, respectively, of a two-dimensional (2D) light guide providing input to a two-section light guide 16. Lateral expansion of the aperture can be accomplished with a one-dimensional (1D) light guide on top of another one-dimensional (1D) light guide, with a two-dimensional (2D) a light guide on top of a one-dimensional (1D) light guide or with a one-dimensional (1D) overlapping (multi-axis) light guide described above. By combining these methods, it is possible to obtain a uniform intensity of the image produced by the light guide and the image projector with minimal dimensions.

On FIG. 26A shows a side view of a two-dimensional (2D) light guide 310 expanding the aperture laterally with a light guide 320 following it (overlapped waveguide 16 embodiment). As shown in the accompanying figure, the light guide 320 is a biaxial light guide that expands the aperture vertically, and as shown in FIG. 26 V, expands the aperture in the transverse direction.

Aperture expansion in the transverse direction using a two-dimensional (2D) light guide can be performed in various ways, as described in PCT/IL2017/051028, filed September 12, 2017, and in PCT/IL2005/000637 (US 7,643,214), both from Lumus Ltd." The biaxial light guide may have any of the above designs. Preferably, the subsequent alignment and joining is done by including overlapping edges as described in PCT/IL2018/050025 filed by "Lumus Ltd." January 8, 2018

On FIG. 27A and FIG. 27B shows side and front views, respectively, of a one-dimensional (1D) light guide providing input to a two-section light guide 16. FIG. 27A shows a side view of a one-dimensional (1D) light guide 410 that expands the aperture laterally with the light guide 320 following it.

The light guide of the head-mounted display transmits the light of the "virtual" image from the projector 2 into the eye 10 of the observer with an increase in the projected aperture. Said transmission through the light guide 16 includes reflections by built-in reflectors (facets) or grating diffraction.

The light guide 16 is transparent to the "outside world", and preferably should not introduce any reflections of the outside world in the direction of the observer's eye 10.

Many light guide designs introduce some reflections of high angle light towards the eye 10. Facet coverage (or grating diffraction efficiency) can be optimized to reduce reflectivity at these angles of incidence. However, high intensity light sources such as a lamp (in a dark environment) or the sun may reflect light of considerable intensity towards the observer.

On FIG. 28 shows a pie chart of an unwanted image overlapping a virtual image. The accompanying figure uses the diagram shown in FIG. 13, however, the attached figure shows only one dot in the field. Light from an external source enters the light guide and generates an unwanted image that overlaps the virtual image.

The external source is designated as 8Is (for example, the sun at a high angle above the observer). Light from an external source 8Is transmitted to the light guide 16 is reflected by the second set of edges 36 at an angle of 4Rs (4R overlap in Fig. 13), from this point the unwanted image follows the image path: 4Rs, 6Ls, 6R and to the viewer 8s.

Obviously, 4Rs is being sent, hence the image will be transmitted to the viewer. However, at other angles, light from an external 8Is source will arrive at 4Rs, which will not be guided by internal reflection, hence no unwanted image will be generated.

Spurious light can also enter the fiber through the 4Rs image when this image is outside the TIR (within one of the circles). This light (interference) penetrates from the other side of the fiber (from the side of the observer). To prevent stray light 8Is or 4Rs from entering, a shroud can be placed on top of the fiber as shown in FIG. 29A.

On FIG. 29A shows a shroud to prevent light entering the light guide at a high angle. The visor 1009 is positioned to advantageously block (from the light guide 16) high-angle stray light 2900 from the front and rear. Light incident at the smaller angle 1007A will not illuminate the focal area 1007B and therefore will not be visible.

On FIG. 29B shows a coating with angle dependent properties to prevent high angle light from entering the fiber. Coating 1011 is made with properties dependent on the angle. This coating 1011 reflects high angle light rays 2900 (relative to the zenith) while transmitting light 1007A at a lower angle as shown in the figure.

On FIG. 30 shows an alternative arrangement of sections. In the accompanying figure, two sections (first section 14 and second section 12) are combined into a single one-dimensional (1D) light guide 1020. This light guide 1020 has two sections adjacent using a different side surface compared to the adjacent surfaces of the overlapping light guide 16 shown in FIG. . 2. The light guide sections 1020 are combined as a superstructure where the propagating light being guided (the two images 4L and 4R shown in FIG. 13) is reflected first by the first set of edges 32 in the first section 14 (4R being the first set of edges 32 shown in FIG. Fig. 13) and then the second set of edges 36 in the second section 12 (6R - the second set of edges 36 shown in Fig. 13). It should be noted that according to this embodiment, the edges are not perpendicular to the outer surfaces of the light guide. Therefore, only one image is reflected in the main direction towards eye 10. For example, only 4R is reflected on 6L, and not 4R on 6R at the same time as 4L on 6L. This single focus alleviates the alignment accuracy requirements that exist in split beam designs.

On FIG. 32A is a schematic side view of an exemplary lighting system. The light guide 16 can be used for a lighting system providing uncolored uniform illumination of image projectors. Light source 3200 provides input illumination illuminating light guide 16. As light 3202 propagates in light guide 16, light 3202 is reflected by 3204 edges of light guide 16 onto image modulator 3215. For example, image modulator 3215 may be a liquid crystal on silicon (LCOS) basis. The reflected image light 3206 passes through the waveguide and is then typically displayed by the optical system 3220. Advantageously, the facet coating properties are polarization dependent, so the fiber 16 acts as a polarization beam splitter. For clarity, polarizers and rotators of the plane of polarization are omitted in this description and figure.

On FIG. 32B is a schematic front view of an exemplary lighting system showing a front view of light guide 16. Light source 3200 projects light 3202 directly (or through light guide) into light guide 16 where the intersection (overlapping) of the faces causes the source aperture to expand laterally within light guide 16 and projects light from light guide 16.

It should be noted that the examples described above, the numerical values used, and the calculation examples are intended to assist in describing embodiments of the present invention. Unintentional typographical errors, mathematical errors and/or the use of simplified calculations do not detract from the usefulness and essential advantages of the invention.

Since the appended claims have been drafted without multiple dependencies, it should be understood that this was done only to accommodate formal requirements in jurisdictions that do not allow such multiple dependencies. It should be noted that all possible combinations of features that will be implied when the claims are multiplied are expressly contemplated and should be considered part of the invention.

It should be understood that the above descriptions of the embodiments of the present invention are intended to serve as examples only, and that many other embodiments of the present invention are possible within the scope of the present invention as defined by the appended claims.

Claims (89)

1. An optical device, comprising: a) a light guide having: (i) a first pair of outer surfaces parallel to each other, and (ii) at least two sets of faces, each of which: (A) includes a plurality of partially reflective faces parallel to one another, and (B) located between said first pair of outer surfaces, and b) in this case, in each of the mentioned sets of faces, the corresponding faces are located: (i) at an oblique angle with respect to said first pair of outer surfaces, and (ii) non-parallel with respect to another of said sets of faces, in this case, if there is a first set of lines of intersection between the planes of the first set of faces with the plane of the outer surface of the fiber and if there is a second set of lines of intersection between the planes of the second set of faces with the same plane of the outer surface of the fiber, the first and second sets of lines are non-parallel. 2. The device according to claim. 1, characterized in that said light guide contains two of the said sets of faces. 3. The device according to claim 1, characterized in that said light guide contains all three of said sets of faces. 4. The device according to claim. 1, characterized in that at least the first set of said sets of faces provides continuous overlap when viewed in the direction of view of the corresponding area of the location of the said first set of faces, so that at least part of the light in the said direction of view passes through at least one face from at least two sets of faces in said light guide. 5. The device according to claim. 1, characterized in that each of the mentioned sets of faces fills the overlap area, while the said filling is the area on which each of the mentioned sets of faces is placed, and at the same time, the said overlapping areas of two of the mentioned sets of faces overlap at least partially. 6. The device according to claim. 1, characterized in that the said light guide is a single-section light guide, including: (a) the first set of said facet sets, and (b) the second set of said facet sets, wherein said first and second sets overlap in the same plane along the thickness of said light guide, said thickness being defined between said first pair of outer surfaces. 7. Device according to claim 1, characterized in that (a) said light guide has a thickness defined between said first pair of outer surfaces, (b) the faces of the first of said sets of faces extend through said thickness so as to enclose the first layer from the first thickness value to the second thickness value, and (c) the faces of the second of said sets of faces extend through said thickness so as to enclose the second layer from a third thickness value to a fourth thickness value. 8. The device according to claim 7, characterized in that said first layer and said second layer encompass overlapping layers. 9. The device according to claim 7, characterized in that said first layer and said second layer cover the same thickness of the layers. 10. The device according to claim 7, characterized in that said first layer and said second layer do not overlap. 11. The device according to claim. 1, characterized in that the section of faces is limited by a bounding pair of surfaces parallel to or coinciding with said first pair of outer surfaces, while said section contains at least one of said sets of faces. 12. The device according to p. 11, characterized in that the said light guide is a single-section light guide, including: (a) a first section from said edge section, wherein said first section contains two of said edge sets. 13. The device according to claim. 11, characterized in that the said light guide is a two-section light guide, including: (a) a first section of said edge section containing a first bounding pair of surfaces, and (b) a second section of said edge section containing a second bounding pair of surfaces, wherein one surface of said first bounding pair of surfaces is adjacent to one surface of said second bounding pair of surfaces, wherein said first and second bounding pairs of surfaces are parallel. 14. The device according to claim 13, characterized in that the said light guide is three-section, also including: (a) a third section of said edge section comprising a third bounding pair of surfaces, wherein one surface of said third bounding pair of surfaces is adjacent to one surface of either said first bounding pair of surfaces or said second bounding pair of surfaces, and wherein said third boundary pair of surfaces is parallel to said first and second boundary pairs of surfaces. 15. The device according to claim 11, characterized in that said light guide includes: (a) a first section of said edge section containing a first bounding pair of surfaces, and (b) a second section of said edge section containing a second bounding pair of surfaces, (c) wherein said first and second boundary pairs of surfaces are parallel, and (d) at least one contact surface, each said contact surface: (i) is located at least partially between two sections, and (ii) parallel to said first pair of outer surfaces, (e) wherein said contact surface is at least one surface selected from the group consisting of: (i) a partially reflective surface, (ii) a partially reflective optical coating, (iii) a transitional section from the material of one of the said sections to another material of the other of the said sections, (iv) a polarization-changing coating, and (v) flexible intermediate layer. 16. The device according to claim. 1, characterized in that the second of the said sets of faces is made so as to carry out the removal of light from the said light guide, when therein, said second set of faces, having a fixed number of faces, overlaps along the optical axis in the direction of a predetermined point of observation of the output of light from said light guide through one of said first pair of outer surfaces. 17. The device according to claim 1, further comprising: (a) an input device configured to direct light into said light guide so that said light propagates by internal reflection from said first pair of outer surfaces through said light guide in the direction of propagation of the first component in the plane, and (b) wherein in each of said sets of faces, the respective faces are oriented to refract a portion of said light directed by internal reflection of said light guide to propagate along said light guide in the propagation direction of the second component in a plane not parallel to said first component in the plane. 18. The device according to claim 17, characterized in that said input device is a second light guide, including: (a) a second pair of outer surfaces parallel to one another, and (b) set of faces. 19. The device according to claim 1, characterized in that in at least one of the said sets of faces, the distance between each of the said partially reflecting faces is made such that in the field of view of the image reflected by the said one of the mentioned sets of faces, the step with which double reflection propagates along said fiber, did not coincide with the integer value of said distance. 20. The device according to claim 1, characterized in that the first angle of said partially reflective faces in the first set of said at least two sets of faces differs from the second angle of said partially reflective faces in the second set of said at least two sets of faces, when therein, said angles are given with respect to said first pair of outer surfaces. 21. The device according to claim 1, characterized in that the first angle of said partially reflective edges in the first set of said at least two sets of edges is substantially the same as the second angle of said partially reflective edges in the second set of at least mentioned two sets of faces, wherein said angles are given relative to said first pair of outer surfaces, and said first set is rotated relative to said second set. 22. The device according to claim 1, also containing: a) a light source (3200) for introducing illumination (3202) into said light guide (16), and b) an image modulator (3215) reflecting diffused light (3204) produced by said light guide from said input illumination, said reflection producing reflected image light (3206) which intersects said light guide. 23. Method for the production of an optical device that contains a light guide (16) having: (i) at least two sets of faces (32, 36) between the first pair of outer surfaces (22, 24), (ii) said outer surfaces (22, 24) are parallel to one another, (iii) each of said sets of faces (32, 36) contains a plurality of partially reflecting faces parallel to one another, and at the same time, in each of the mentioned sets of faces (32, 36) the mentioned corresponding faces are located at an oblique angle with respect to the mentioned first pair of outer surfaces (22, 24), and non-parallel with respect to the other of the mentioned sets of faces (32, 36), wherein the method includes: (a) providing a first array (52) of partially reflective faces, (b) providing a second array (56) of partially reflective faces, and (c) optical connection of said first array (52) and said second array (56) so that said faces of said first array (32) and said faces of said second array (36) are located at an oblique angle relative to said first pair of outer surfaces ( 22, 24), and not parallel to one another, in this case, if there is a first set of lines of intersection between the planes of the first set of faces with the plane of the outer surface of the fiber and if there is a second set of lines of intersection between the planes of the second set of faces with the same plane of the outer surface of the fiber, the first and second sets of lines are non-parallel. 24. The method according to claim 23, characterized in that said optical connection is made by pressing said first and second arrays with mastic glue between said first and second arrays. 25. The method according to claim 23, characterized in that the first angle of said partially reflective faces in said first array differs from the second angle of said partially reflective faces in said second array, wherein said angles are set relative to the respective outer surfaces of said arrays. 26. The method according to claim 23, characterized in that the first angle of said partially reflective faces in said first array is essentially the same as the second angle of said partially reflective faces in said second array, wherein said angles are given relative to the respective outer surfaces of said arrays, and said first array is rotated with respect to said second array before the optical connection of said arrays. 27. Method for the production of an optical device that contains a light guide (16) having: (i) at least two sets of faces (32, 36) between the first pair of outer surfaces (22, 24), (ii) said outer surfaces (22, 24) are parallel to one another, (iii) each of said sets of faces (32, 36) contains a plurality of partially reflective faces parallel to one another, and wherein in each of the said sets of faces (32, 36) the said respective faces are located at an oblique angle relative to the first pair of outer surfaces (22, 24), and not parallel to the other mentioned set of faces (32, 36), wherein the method includes: (a) providing a plurality of transparent flat windows (50) having partially reflective surfaces; (b) optical connection between said windows (50) so as to form the first package (51), (c) cutting said first package (51) to form a plurality of first flat arrays (52), wherein said cutting is performed through a plurality of windows (50) and at an oblique angle relative to at least two pairs of opposite sides of said first package (70), (d) optically interconnecting a plurality of said first planar arrays (52) so as to form a stack (70) of arrays, and (e) cutting said stack (70) of arrays to form at least one said light guide (71, 16), wherein said cutting is performed through a plurality of said first flat arrays (52) and at an oblique angle with respect to at least two pairs of opposite sides mentioned package (70) of arrays, in this case, if there is a first set of lines of intersection between the planes of the first set of faces with the plane of the outer surface of the fiber and if there is a second set of lines of intersection between the planes of the second set of faces with the same plane of the outer surface of the fiber, the first and second sets of lines are non-parallel. 28. The method according to claim 27, characterized in that said first planar arrays are polished and coated before the optical connection to form said array package. 29. A method for expanding an optical aperture in two dimensions by obtaining an image by introducing light into the said optical device according to claim 1.

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