Optically Enhanced Waveguide

Abstract

An optical expansion waveguide is disclosed, which includes a first waveguide base (1) and a second waveguide base (2). The first waveguide base (1) expands the light entering therein along a first dimension, the first waveguide base (1) includes a plurality of first reflecting surfaces (101) arranged in sequence, and the second waveguide base (2) expands the light inside therein along a second dimension, the second waveguide base (2) includes a plurality of second reflecting surfaces (201) arranged in sequence. At least one of the first reflecting surface (101) and the second reflecting surface (201) is curved at least locally, thereby changing the exit angle of the light, and the image distance formed from the light emitted by the second waveguide base (2) meets a predetermined requirement.

Description

cross reference

[0001] This application claims priority from a Chinese patent application filed with the China Patent Office on January 20, 2022, bearing application number 202210065286.6 and entitled "Optical Extended Waveguide," the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present invention relates to the field of optical devices, and more particularly to optically enhanced waveguides. [Background technology]

[0003] Near-eye display is a hot technology field, and its optical system includes microdisplays and optical elements. Currently, there are many optical solutions for near-eye display on the market.

[0004] Furthermore, the arrayed waveguide solution uses semi-transparent and semi-reflective optical surfaces to achieve light expansion and exit pupil, and follows the law of reflection that the angle of incidence is equal to the angle of reflection, so there is no dispersion effect on the incident light of the three primary colors forming a full-color display, and the formed image can be guaranteed to have no obvious color shift, meeting the most basic requirements of a display device and providing obvious advantages for optimizing the design of head-mounted devices and improving aesthetics.

[0005] However, due to the characteristic of this solution that focuses an image at infinity, the display device according to this solution is applicable to people with visual acuity of about 1.2, while the visual acuity of an average person (including visual correction) is about 1.0, so when using such a display device, the wearer cannot see a clear and good image, which causes great inconvenience to the user. To solve this problem, the mainstream solution uses an external device for assistance and adjustment, which not only increases the volume and weight of the display device but also reduces the comfort and perception experience of the user. Summary of the Invention [Problem to be solved by the invention]

[0006] In view of this, an object of the present invention is to provide an optical extension waveguide that can be applied to an optical display device to change the image distance, is suitable for users with visual impairments, and has a thin and lightweight structure. [Means for solving the problem]

[0007] To achieve the above objectives, the present invention provides the following technical solutions: an optically extended waveguide, the optically extended waveguide including a first waveguide base and a second waveguide base; the first waveguide base expands the beam entering the first waveguide base along a first dimension, the first waveguide base includes a plurality of sequentially arranged first reflecting surfaces, the first reflecting surfaces at least partially reflect the light incident on the first reflecting surfaces, and couple at least a portion of the light into the second waveguide base; the second waveguide base expands the beam entering the second waveguide base along a second dimension, the second waveguide base includes a plurality of second reflective surfaces arranged in sequence, the second reflective surfaces at least partially reflect the light entering the second reflective surfaces, and emit at least a portion of the light to the outside of the second waveguide base; By making at least one of the first reflecting surface and the second reflecting surface at least locally curved, the image distance formed from the light emitted from the second waveguide base satisfies a predetermined requirement.

[0008] Preferably, at least a portion of the first reflecting surface is a curved surface, and the first reflecting surface diverges the light reflected by the first reflecting surface. Alternatively, at least a local portion of the second reflecting surface is a curved surface, and the second reflecting surface diverges the light reflected by the second reflecting surface.

[0009] Preferably, each of the first reflecting surfaces forms an inclination angle with respect to the first dimension.

[0010] Preferably, the first waveguide base further includes at least a first set of opposing surfaces, and light entering the first waveguide base is reflected by each of the first set of opposing surfaces and propagates forward.

[0011] Preferably, at least one of the first set of opposing surfaces is curved at least locally to change the angle at which light reflected from that surface strikes the first reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the second waveguide base meets a predetermined requirement.

[0012] Preferably, at least one surface of the first set of opposing surfaces is divergent in the light reflected therefrom.

[0013] Preferably, the second waveguide base further includes at least a third set of opposing surfaces, and light entering the second waveguide base at each of the third set of opposing surfaces is reflected and propagated forward.

[0014] Preferably, each of the second reflecting surfaces forms an inclined angle with respect to one of the opposing surfaces of the third set.

[0015] Preferably, the inclination angle formed by the second reflecting surface with respect to one surface of the third set of opposing surfaces as a coupling output surface is greater than 0° and less than 45°, and when the second reflecting surface rotates counterclockwise with respect to the one surface, the inclination angle formed by the second reflecting surface with respect to the surface is positive.

[0016] Preferably, at least one of the third set of opposing surfaces is curved at least locally to change the angle at which light reflected from that surface strikes the second reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the second waveguide base meets a predetermined requirement.

[0017] Preferably, at least one surface of the third set of opposing surfaces diverges light reflected by that surface.

[0018] Preferably, the first waveguide base further includes a first coupling output surface that causes the reflected light from the first reflecting surface to be emitted outside the first waveguide base, and the second waveguide base further includes a second coupling input surface that causes the light emitted from the first waveguide base to enter the second waveguide base, and the first coupling output surface and the second coupling input surface are optically coaxial.

[0019] Preferably, the first coupling output surface is a flat surface, an inclined surface, a sawtooth surface or a curved surface, and the second coupling input surface is a flat surface, an inclined surface, a sawtooth surface or a curved surface.

[0020] Preferably, the first waveguide base is provided in front of, behind or above the second waveguide base. [Effects of the Invention]

[0021]

[0013] As can be seen from the above technical solutions, the optical expansion waveguide provided by the present invention includes a first waveguide base and a second waveguide base, wherein the first waveguide base expands a beam incident thereon along a first dimension, the first waveguide base includes a plurality of sequentially arranged first reflective surfaces, the first reflective surfaces at least partially reflect the light incident thereon to couple at least a portion of the light into the second waveguide base, the second waveguide base expands the beam incident thereon along a second dimension, the second waveguide base includes a plurality of sequentially arranged second reflective surfaces, the second reflective surfaces at least partially reflect the light incident thereon to couple at least a portion of the light out of the second waveguide base. At least one of the first and second reflective surfaces is curved at least locally, thereby changing the light emission angle by the first reflective surface and / or the second reflective surface, so that the image distance formed from the light emitted by the second waveguide base meets a predetermined requirement. Therefore, when the optical expansion waveguide of the present invention is applied to an optical display device, it can change the focused image distance, is suitable for users with visual impairments, and has a thin and light structure. [Brief explanation of the drawings]

[0022] In order to more clearly explain the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings necessary for the description of the embodiments or the prior art, and the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings on the premise that they do not make efforts worthy of inventive step. [Figure 1] FIG. 2 is a schematic diagram of light propagation on a first reflecting surface in one embodiment of the present invention. [Figure 2-1] FIG. 2-3 is a left side view of the optical extension waveguide of FIG. 2-2. [Figure 2-2] 1 is a front view of an optical extension waveguide provided by one embodiment of the present invention. [Figure 3] FIG. 2 is a schematic diagram of a first waveguide-based ray propagation in one embodiment of the present invention. [Figure 4] 3 is a schematic diagram of ray propagation at one surface of the first set of opposing surfaces and at the first reflecting surface in one embodiment of the present invention. [Figure 5] FIG. 10 is a schematic diagram of a second waveguide-based ray propagation in one embodiment of the present invention. [Figure 6] FIG. 10 is a schematic diagram illustrating the propagation of light rays at the second waveguide base to form a corresponding effective light passage aperture in one embodiment of the present invention. [Figure 7] 1 is a schematic diagram of a waveguide-based, curved reflecting surface and surface structure parameters in one embodiment of the present invention; FIG. [Figure 8-1] 10 is a schematic diagram of a curved surface used for one of the opposing surfaces of the waveguide base in one of the embodiments of the present invention. FIG. [Figure 8-2] 10A and 10B are schematic diagrams of other curved surfaces used on either of the opposing surfaces of the waveguide base in any of the embodiments of the present invention. [Figure 9-1-9-4] 3A-3C are schematic diagrams of four embodiments of a first waveguide-based first coupling output surface and a second waveguide-based second coupling input surface according to an embodiment of the present invention; [Figure 10-1-10-3] 3A to 3C are schematic diagrams of three embodiments of the arrangement positions of the first waveguide base and the second waveguide base in an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] In order to allow those skilled in the art to better understand the technical solutions of the present invention, the following clearly and completely describes the technical solutions of the embodiments of the present invention in combination with the drawings of the embodiments of the present invention, and the described embodiments are not all embodiments but only some embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without any inventive efforts are also within the protection scope of the present invention.

[0024] The optical extension waveguide provided in this embodiment includes a first waveguide base and a second waveguide base; the first waveguide base expands the beam entering the first waveguide base along a first dimension, the first waveguide base includes a plurality of first reflective surfaces arranged in sequence, the first reflective surfaces at least partially reflect the light incident on the first reflective surfaces, and couple at least a portion of the light into the second waveguide base; the second waveguide base expands the beam entering the second waveguide base along a second dimension, the second waveguide base includes a plurality of second reflective surfaces arranged in sequence, the second reflective surfaces at least partially reflect the light entering the second reflective surfaces, and emit at least a portion of the light to the outside of the second waveguide base; By making at least one of the first reflecting surface and the second reflecting surface at least locally curved, the image distance formed from the light emitted by the second waveguide base satisfies a predetermined requirement.

[0025] The beam entering the first waveguide base propagates through the first waveguide base, with each portion of the beam incident on a respective first reflecting surface, which at least partially reflects the incident light and couples at least a portion of the light into the second waveguide base, thereby expanding the beam entering the first waveguide base in a first dimension.

[0026] The beam entering the second waveguide base propagates through the second waveguide base, and each portion of the beam is incident on each second reflective surface, which at least partially reflects the incident light and causes at least a portion of the light to exit the second waveguide base, thereby expanding the beam entering the second waveguide base in the second dimension.

[0027] The image distance formed from the light emitted by the second waveguide base is the distance from the viewing position to a corresponding virtual image of the image formed from the light emitted by the second waveguide base.

[0028] If the first reflecting surface of the first waveguide base is at least partially curved, the curved surface can change the reflection angle of the light at the first reflecting surface, the incident angle at which the light couples with the second waveguide base, and the exit angle at which the light exits the second waveguide base. If the second reflecting surface of the second waveguide base is at least partially curved, the curved surface can change the reflection angle of the light at the second reflecting surface and the exit angle at which the light exits the second waveguide base. Therefore, by using a curved surface for at least one of the first reflecting surface and the second reflecting surface, the optical expansion waveguide can change the exit angle of the output light and the image distance formed from the output light of the optical expansion waveguide, and the image distance can meet a predetermined requirement.

[0029] Therefore, when the optical extension waveguide of this embodiment is applied to an optical display device, the image distance can be changed, which is suitable for users with visual impairments, allowing them to see clear and sharp images. Furthermore, the structure of the optical extension waveguide of this embodiment is thin and light.

[0030] In this embodiment, as long as at least a portion of the first reflecting surface of the first waveguide base is curved, the shape and size of the curved surface included in the first reflecting surface are not specifically limited, as long as the exit angle of the light emitted by the second waveguide base can be changed and the image distance formed from the light emitted by the second waveguide base meets a predetermined requirement. The curved surface included in the first reflecting surface may be a curved surface with a constant curvature or a free-form surface. Preferably, the curved surface is used for the first reflecting surface to diverge or converge the light reflected by the first reflecting surface.

[0031] In this embodiment, as long as at least a portion of the second reflecting surface of the second waveguide base is curved, the shape and area of ​​the curved surface included in the second reflecting surface are not specifically limited, as long as the exit angle of the light emitted from the second waveguide base can be changed and the image distance formed from the light emitted from the second waveguide base meets a predetermined requirement. The curved surface included in the second reflecting surface may be a curved surface with a constant curvature or a free-form surface. Preferably, the curved surface is used for the second reflecting surface to diverge or converge the light reflected by the second reflecting surface.

[0032] For example, refer to FIG. 1, which is a schematic diagram of ray propagation at a first reflecting surface in one embodiment. As shown in the drawing, rays L1 and L2 reflected by the surface 100 of the first waveguide base are incident on a first reflecting surface 101, which is a curved surface. They form reflected rays L1′ and L2′ through the first reflecting surface 101. The rays L1 and L2 are reflected by a reference flat surface 102 of the first reflecting surface 101, forming reflected rays L1″ and L2″ through the reference flat surface 102 of the first reflecting surface 101. The reflected rays L1′ and L2′ diverge. This reduces the distance of the image formed from the light emitted by the second waveguide base. For a visually impaired user, the image can be focused on the retina of the visually impaired user.

[0033] Based on Figure 1, taking the propagation of light on the first reflecting surface of the first waveguide base as an example, the principle of image distance change is realized by using a curved surface for the first reflecting surface. Similarly, for the second waveguide base, the principle of image distance change is also based on the above principle by using a curved surface for its second reflecting surface.

[0034] In the first waveguide base, each of the first reflecting surfaces forms an inclination angle with respect to the first-dimensional direction. The inclination angle of the first reflecting surface with respect to the first-dimensional direction means that the chord of the first reflecting surface and the first-dimensional direction are neither parallel nor perpendicular. Correspondingly, the inclination angle formed by the first reflecting surface with respect to the first-dimensional direction is the included angle between the chord of the first reflecting surface and the first-dimensional direction. When light propagated through the first waveguide base is incident on a first reflecting surface, a portion of the light energy is transmitted through the first reflecting surface and continues to propagate, and another portion of the light energy is reflected and coupled into the second waveguide base.

[0035] In this embodiment, the magnitude of the inclination angle formed by each of the first reflecting surfaces with respect to the first direction is not limited, as long as at least a portion of the light propagating within the first waveguide base is reflected and coupled into the second waveguide base when the light is incident on the first reflecting surface. In practical application, the size of the first waveguide base and the size of the second waveguide base are used to determine the expansion requirement of the light in the first direction, and preferably, the structure of the optical expansion waveguide is thin and light while meeting the expansion requirement of the light.

[0036] For the projection plane of the first reflecting surface on a plane parallel to the first-dimensional direction, the plane parallel to the first-dimensional direction is located on the light-reflecting side of the first reflecting surface and determines the light passing aperture of the output light of the optical expansion waveguide in the first-dimensional direction. When applied to an optical display device, the light passing aperture of the output light of the optical expansion waveguide in the first-dimensional direction must ensure that the image from the image source is fully expanded, i.e., the image formed by the output light of the optical expansion waveguide contains the complete information of the image in the first-dimensional direction.

[0037] The first waveguide base further includes at least a first set of opposing surfaces, and light entering the first waveguide base is reflected by each of the first set of opposing surfaces and propagates forward. Specifically, when light is incident on each of the first set of opposing surfaces, the total internal reflection condition is satisfied. The first set of opposing surfaces may or may not be parallel to each other, as long as the light is reflected by each of the first set of opposing surfaces and propagates forward.

[0038] Preferably, the first waveguide base further includes a second set of opposing surfaces, the second set of opposing surfaces and the first set of opposing surfaces forming a closed cross section, and light entering the first waveguide base is reflected by each of the first set of opposing surfaces and the second set of opposing surfaces to propagate forward. Specifically, when light is incident on each of the second set of opposing surfaces, the total internal reflection condition is satisfied. The second set of opposing surfaces may or may not be parallel to each other, as long as the light is reflected by each of the second set of opposing surfaces to propagate forward.

[0039] 2-1, 2-2, and 3 are combined for illustrative purposes. FIG. 2-1 is a left-side view of the optical extension waveguide of FIG. 2-2, FIG. 2-2 is a front view of the optical extension waveguide provided in one embodiment, and FIG. 3 is a schematic diagram of light propagation in a first waveguide base in one embodiment. As shown in the drawings, within the cross section formed by four surfaces 1-A, 1-B, 1-C, and 1-D of the first waveguide base 1, light entering the first waveguide base 1 is reflected by each surface and propagates forward. During the propagation process, when the light encounters the first reflecting surface 101, it reflects a portion of the light energy at a certain energy ratio, thereby coupling the light into the second waveguide base 2.

[0040] In the first waveguide base 1 of Figure 3, the first set of opposing surfaces 1-A and 1-B are parallel to each other, and the second set of opposing surfaces 1-C and 1-D are parallel to each other, and Figure 3 is described for illustrative purposes only. In other embodiments, the first set of opposing surfaces may not be parallel, and the second set of opposing surfaces may not be parallel.

[0041] In one preferred embodiment, at least one surface of the first set of opposing surfaces is curved at least locally to change the angle of incidence of light reflected from that surface onto the first reflecting surface, thereby helping to ensure that the image distance formed from the light emitted from the second waveguide base meets a predetermined requirement. At least one surface of the first set of opposing surfaces is curved at least locally to change the angle of reflection of light after passing through that surface, and to change the angle of incidence of light reflected from that surface onto the first reflecting surface, thereby helping to change the image distance formed from the light emitted from the optical expansion waveguide.

[0042] In this embodiment, the shape and area of ​​the curved surface included in any of the first set of opposing surfaces are not specifically limited, as long as the emission angle of the light emitted from the second waveguide base can be changed and the image distance formed from the light emitted from the second waveguide base meets a predetermined requirement. The curved surface included in any of the first set of opposing surfaces may be a curved surface with a constant curvature or a free-form surface. Preferably, the curved surface included in any of the first set of opposing surfaces diverges or converges the reflected light from that surface.

[0043] For example, as shown in FIG. 4, FIG. 4 is a schematic diagram of ray propagation on one surface of the first set of opposing surfaces and the first reflecting surface in one embodiment, as shown in the drawing, surface 100 is one surface of the first set of opposing surfaces of the first waveguide base 1, by making surface 100 a curved surface (its reference plane is surface 103), the reflected rays of incident light L3, L4 on surface 100 become divergent, and the reflected rays L3', L4' after the light rays are reflected by the first reflecting surface 101 become divergent, as a result, the image distance formed from the light emitted by the second waveguide base 2 becomes smaller.

[0044] The second waveguide base further includes at least a third set of opposing surfaces, and light entering the second waveguide base is reflected by each of the third set of opposing surfaces and propagates forward. Specifically, when light is incident on each of the third set of opposing surfaces, the total internal reflection condition is satisfied. The third set of opposing surfaces may or may not be parallel to each other, as long as the light is reflected by each of the third set of opposing surfaces and propagates forward.

[0045] Preferably, each second reflecting surface forms an inclined angle with one of the third set of opposing surfaces. The inclination angle of the second reflecting surface with a surface means that the chord of the second reflecting surface is neither parallel nor perpendicular to the surface. Correspondingly, the inclination angle of the second reflecting surface with a surface is the included angle between the chord of the second reflecting surface and the surface. If the surface is curved, the inclination angle of the second reflecting surface with the surface is the included angle between the chord of the second reflecting surface and the surface. When light propagated through the second waveguide base is incident on the second reflecting surface, a portion of the light energy is transmitted through the second reflecting surface and continues to propagate, and another portion of the light energy is reflected and exits the second waveguide base.

[0046] 2-1, 2-2, and 5, which are combined for illustrative purposes, and FIG. 5 is a schematic diagram of light propagation in a second waveguide base in one embodiment. As shown in the drawing, light coupled from the first waveguide base 1 to the second waveguide base 2 is reflected by surfaces 2-A and 2-B of the second waveguide base 2 and propagates forward. During propagation, when the light encounters the second reflecting surface 201, a portion of the light energy is reflected at a certain energy ratio, causing a portion of the light to exit the second waveguide base 2.

[0047] In this embodiment, the magnitude of the inclination angle formed by each second reflecting surface with respect to any of the third set of opposing surfaces is not limited, as long as at least a portion of the light propagating within the second waveguide base is reflected and emitted out of the second reflecting surface when the light is incident on the second reflecting surface. In practical application, the size of the first waveguide base and the size of the second waveguide base may be determined to determine the requirement for expanding the light in the second dimension.

[0048] For example, as shown in FIG. 6, in one embodiment, a schematic diagram of light propagating through the second waveguide base 2 to form a corresponding effective light aperture is shown. When the light propagating through the second waveguide base 2 encounters each of the second reflective surfaces S1, S2, S3, S4, and S5, it is reflected, causing at least a portion of the light to exit the second waveguide base 2. The total projection area S of each of the second reflective surfaces S1, S2, S3, S4, and S5 on surface 2-A determines the effective light aperture of the optical expansion waveguide. When applied to an optical display device, the effective light aperture of the optical expansion waveguide must fully expand the image from the image source, i.e., ensure that the image formed by the output light of the optical expansion waveguide contains complete image information in both the first and second dimensional directions.

[0049] Preferably, the tilt angle formed by the second reflecting surface with respect to one of the surfaces of the third set as the coupling output surface is greater than 0° and less than 45°, where β is 0°<β≦45°, and when the second reflecting surface rotates counterclockwise with respect to the one surface, the tilt angle formed by the second reflecting surface with respect to the one surface is positive. With respect to one of the surfaces of the third set as the coupling output surface, the light reflected by the second reflecting surface exits the second waveguide base through the surface. In this way, the light is expanded by the second reflecting surface, and the thickness of the second waveguide base can be reduced, making the entire waveguide thinner and lighter.

[0050] In one preferred embodiment, at least one surface of the third set of opposing surfaces is curved at least partially to change the angle of incidence of the light reflected from that surface onto the second reflecting surface, thereby helping to ensure that the image distance formed from the light emitted from the second waveguide base meets a predetermined requirement. By curved at least one surface of the third set of opposing surfaces, the angle of reflection of the light after passing through that surface can be changed, and the angle of incidence of the light reflected from that surface onto the second reflecting surface can be changed, thereby, in combination with the first reflecting surface using a curved surface or the second reflecting surface using a curved surface, realizing the change in the image distance formed from the light emitted from the optical expansion waveguide.

[0051] In this embodiment, the shape and area of ​​the curved surface included in any of the third set of opposing surfaces are not specifically limited, as long as the emission angle of the light emitted from the second waveguide base can be changed and the image distance formed from the light emitted from the second waveguide base meets a predetermined requirement. The curved surface included in any of the third set of opposing surfaces may be a curved surface with a constant curvature or a free-form surface. Preferably, the curved surface included in any of the third set of opposing surfaces diverges or converges the reflected light from that surface.

[0052] When the optically enhanced waveguide is applied to an optical display device, in order to meet the requirements of resolution, contrast, clarity, etc. of the generated image, if a curved surface is used for the first reflective surface of the first waveguide base and at least one surface of the first set of opposing surfaces, the curved surface parameters of the first reflective surface of the first waveguide base and any surface of the first set of opposing surfaces should satisfy a certain relationship. If a curved surface is used for the second reflective surface of the second waveguide base and at least one surface of the third set of opposing surfaces, the curved surface parameters of the second reflective surface of the second waveguide base and any surface of the third set of opposing surfaces should satisfy a certain relationship. Referring to FIG. 7 in conjunction, FIG. 7 is a schematic diagram of the structural parameters of a reflective surface and surface using a curved surface of any waveguide base in one embodiment. The optical design is performed based on a collimated main axis beam emitted from an on-axis object point. When the main axis beam is perpendicularly incident on the coupling input surface of the waveguide base, the corresponding relationships of each parameter are as follows: α R2 =α R1 -β o ; α R1 =π / 2-β i ; β i is the angle between the coupling input plane and the horizontal reference plane of the waveguide base surface, and β o is the angle between the plane on which the chord of the curved reflecting surface is located and the horizontal reference plane of the waveguide base surface, and α R1 is the angle between the principal axis ray and the horizontal reference plane normal of the waveguide base surface, and α R2 is the angle between the principal axis ray and the reference surface normal of the coupling output surface.

[0053] h s =h r =N*(λ / 2); H r =H / (sin(β o )); H s =H / (tan(β o )); h s is the local curved arrow height of the curved waveguide corresponding to a single reflecting surface, and H sis the local chord length of the curved waveguide corresponding to a single reflecting surface, and h r is the local curved arrow height corresponding to the curved reflecting surface itself, and H r is the local chord length corresponding to the curved reflective surface itself; N is the number of apertures according to the image distance adjustment needs; λ is the reference wavelength selected during optical design. Based on the specific image distance adjustment needs, the required local curvature of the curved reflective surface and the local curvature radius of the waveguide-based curved surface can be calculated using the corresponding arrow height and chord length.

[0054] For example, refer to Figures 8-1 and 8-2, which are schematic diagrams illustrating the use of a curved surface for one of the opposing surfaces of one of the waveguide bases in this embodiment, and as shown in the drawings, one of the opposing surfaces of the waveguide base may be a free-form surface, a concave surface, or a convex surface.

[0055] The first waveguide base further includes a first coupling output surface that causes the reflected light from the first reflecting surface to radiate out of the first waveguide base, and the second waveguide base further includes a second coupling input surface that causes the light radiated from the first waveguide base to enter the second waveguide base, and the first coupling output surface and the second coupling input surface are optically coaxial. The first coupling output surface and the second coupling input surface being optically coaxial means that the first coupling output surface and the second coupling input surface are parallel to each other corresponding to a local optical axis.

[0056] In this embodiment, the shape of the first coupling output surface of the first waveguide base and the shape of the second coupling input surface of the second waveguide base are not limited, as long as the first coupling output surface and the second coupling input surface are optically coaxial. The first coupling output surface may be, but is not limited to, a flat surface, an inclined surface, a sawtooth surface, or a curved surface, and the second coupling input surface may be, but is not limited to, a flat surface, an inclined surface, a sawtooth surface, or a curved surface. As an example, refer to Figures 9-1 to 9-4, which respectively show four embodiments of the first coupling output surface of the first waveguide base and the second coupling input surface of the second waveguide base in this embodiment.

[0057] In this embodiment, the relative positions of the first waveguide base and the second waveguide base are not limited, as long as the light coupled out from the first waveguide base enters the second waveguide base. For example, see Figures 10-1 to 10-3, which respectively show three embodiments of the arrangement positions of the first waveguide base and the second waveguide base in this embodiment. As shown in the drawings, the first waveguide base 1 is provided in front of, behind, or above the second waveguide base 2.

[0058] The optical extension waveguide of this embodiment is applicable to near-eye display devices, such as head-mounted devices, and can change the image distance, making it suitable for users with visual impairments. Its thin and light structure improves the user's comfort and perception experience.

[0059] The above is a detailed introduction to the optical extension waveguide provided by the present invention. Specific examples are used in this specification to describe the principles and embodiments of the present invention, and the description of the above examples is merely used to understand the method and spirit of the present invention. Those skilled in the art may make some improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. an optically extended waveguide, the optically extended waveguide including a first waveguide base and a second waveguide base; the first waveguide base expands the beam entering the first waveguide base along a first dimension, the first waveguide base includes a plurality of sequentially arranged first reflecting surfaces, the first reflecting surfaces at least partially reflect the light incident on the first reflecting surfaces, and couple at least a portion of the light into the second waveguide base; the second waveguide base expands the beam entering the second waveguide base along a second dimension, the second waveguide base includes a plurality of second reflective surfaces arranged in sequence, the second reflective surfaces at least partially reflect the light entering the second reflective surfaces, and emit at least a portion of the light to the outside of the second waveguide base; An optical extension waveguide characterized in that by making at least a local portion of the first reflecting surface a curved surface and at least a local portion of the second reflecting surface a curved surface, the image distance formed from the light emitted by the second waveguide base meets a specified requirement.

2. At least a portion of the first reflecting surface is a curved surface, and the first reflecting surface diverges the light reflected by the first reflecting surface; 2. The optical extension waveguide according to claim 1, wherein at least a portion of the second reflecting surface is curved, and the second reflecting surface diverges the light reflected by the second reflecting surface.

3. The optical expansion waveguide according to claim 1 , wherein each of the first reflecting surfaces forms an inclination angle with respect to the first dimension.

4. 2. The optical extension waveguide of claim 1, wherein the first waveguide base further comprises at least a first set of opposing surfaces, and light entering the first waveguide base is reflected by each of the first set of opposing surfaces and propagates forward.

5. 5. The optical expansion waveguide of claim 4, wherein at least one surface of the first set of opposing surfaces is curved at least locally, thereby changing the incident angle of the reflected light from that surface onto the first reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the second waveguide base meets a predetermined requirement.

6. 6. The optical enhancement waveguide of claim 5, wherein at least one surface of the first set of opposing surfaces diverges light reflected from that surface.

7. 2. The optical extension waveguide of claim 1, wherein the second waveguide base further comprises at least a third set of opposing surfaces, and light entering the second waveguide base is reflected by each of the third set of opposing surfaces and propagates forward.

8. 8. The optical extension waveguide of claim 7, wherein each of the second reflecting surfaces forms an inclined angle with respect to one of the opposing surfaces of the third set.

9. 9. The optical extension waveguide of claim 8, wherein the inclination angle formed by the second reflecting surface with respect to one surface of the third set of opposing surfaces as a coupling output surface is greater than 0° and less than 45°, and when the second reflecting surface rotates counterclockwise with respect to the one surface, the inclination angle formed by the second reflecting surface with respect to the surface is positive.

10. 8. The optical extension waveguide of claim 7, wherein at least one surface of the third set of opposing surfaces is curved at least partially, thereby changing the incident angle of the reflected light from that surface onto the second reflecting surface, thereby helping to ensure that the image distance formed from the light emitted by the second waveguide base meets a predetermined requirement.

11. 11. The optical enhancement waveguide of claim 10, wherein at least one surface of the third set of opposing surfaces diverges light reflected by that surface.

12. The optical extension waveguide according to any one of claims 1 to 11, characterized in that the first waveguide base further includes a first coupling output surface that radiates the reflected light of the first reflecting surface to the outside of the first waveguide base, and the second waveguide base further includes a second coupling input surface that causes the light emitted from the first waveguide base to enter the second waveguide base, and the first coupling output surface and the second coupling input surface are optically coaxial.

13. 13. The optical extension waveguide of claim 12, wherein the first coupling output surface is a flat surface, an inclined surface, a sawtooth surface, or a curved surface, and the second coupling input surface is a flat surface, an inclined surface, a sawtooth surface, or a curved surface.

14. 12. The optical extension waveguide according to claim 1, wherein the first waveguide base is disposed in front of, behind or above the second waveguide base.

Images