Display including light-guiding optical elements that involve two-dimensional scaling

Abstract

The display (10) includes a flat light-directing optical element (LOE) (100) having first and second progressive deflection configurations associated with first and second regions (110, 120) of the LOE. A support structure (106), such as an eyeglass frame, supports the LOE against the user's eyes. An image projector (200) injects a collimated image into the LOE via a reflective incoupling surface (131), which is preferably oriented obliquely with respect to both the primary horizontal and vertical axes of the LOE. A multi-component wedge (132) is preferably used to compensate for chromatic aberration.

Description

Technical Field

[0001] The present invention relates to an optical system, and more particularly to an optical system including a light guiding optical element (LOE) for achieving optical aperture expansion.

Background Art

[0002] Many near-eye display systems include a transparent light guiding optical element (LOE) or "waveguide" placed in front of the user's eye, which transmits an image within the LOE by internal reflection and then externally couples the image towards the user's eye by a suitable output coupling mechanism. The output coupling mechanism may be based on an embedded partial reflector or "facet", or may use a diffraction pattern. The following description mainly refers to facet-based outcoupling configurations, but it should be understood that various features of the present invention are also applicable to diffraction configurations.

[0003] To use a small image projector to provide a desired field of view (FOV), various systems employ two-dimensional aperture expansion either through two sets of embedded partial reflectors, each achieving a different-sized aperture expansion, or by two diffractive optical elements. Examples of such devices can be found in PCT Patent Application Publication No. 2020 / 049542A1 assigned concurrently with this application.

[0004] Compact head-mounted displays pose design challenges. The geometry of the waveguide itself imposes strict requirements. Preferably, the projector should be integrated to aesthetically follow the geometry of the eyeglass frame that supports the waveguide, but the requirements from the waveguide typically determine a preferred orientation of the projector that is not favorable for aesthetic requirements.

Summary of the Invention

[0005] The present invention is a display. According to the teaching of embodiments of the present invention, a display is provided for directing image illumination to an eye movement box for viewing by the user's eyes, the display comprising: (a) a light guide optical element (LOE) formed of a transparent material, having (i) a set of mutually parallel main outer surfaces, (ii) a first progressive deflection configuration associated with the LOE in a first region of the LOE, and (iii) a second progressive deflection configuration associated with the LOE in a second region of the LOE; (b) a support configuration configured to support the LOE with respect to the user's head, wherein one of the main outer surfaces faces and is oriented toward the user's eye, such that the X-axis parallel to the main outer surfaces is oriented horizontally, and the Y-axis is parallel to the main outer surfaces and perpendicular to the X-axis; and (c) a configuration for projecting a collimated image from a projector aperture. The configured image projector comprises (d) a reflective incoupling surface, wherein the collimated image includes a principal ray aligned with the optical axis of the image projector, and the LOE, image projector, and reflective incoupling surface are arranged such that the collimated image projected from the image projector is deflected by reflection from the reflective incoupling surface, incoupled in the LOE, propagated in a first direction within the LOE by internal reflection from the principal outer surface toward a first region, reoriented by a first progressive deflection configuration, propagated in a second direction within the LOE by internal reflection from the principal outer surface toward a second region, and reoriented by a second progressive deflection configuration to outcouple from the LOE toward the user's eyes, and the reflective incoupling surface is oriented obliquely with respect to both the X and Y axes.

[0006] According to further features of one embodiment of the present invention, the reflective incoupling surface intersects with one of the main outer surfaces and is partially within the thickness of the LOE and partially outside the thickness.

[0007] According to further features of one embodiment of the present invention, the reflective incoupling surface is at least partially provided by the surface of a prism attached to the edge of the LOE.

[0008] According to further features of one embodiment of the present invention, the reflective incoupling surface is provided at least partially by the surface of a prism attached to one of the main outer surfaces.

[0009] A further feature of one embodiment of the present invention also provides a transparent wedge element deployed in the optical path between an image projector and a reflective incoupling surface, wherein the transparent wedge provides an input surface associated with the projector aperture and an output surface parallel to one of the main outer surfaces of the LOE.

[0010] According to the teaching of one embodiment of the present invention, a display is provided for directing image illumination to an eye movement box for viewing by the user's eye, the display comprising: (a) a light guide optical element (LOE) formed of a transparent material, having (i) a set of mutually parallel main outer surfaces, (ii) a first progressive deflection configuration associated with the LOE in a first region of the LOE, and (iii) a second progressive deflection configuration associated with the LOE in a second region of the LOE; (b) a support configuration configured to support the LOE with respect to the user's head, wherein one of the main outer surfaces faces and is oriented toward the user's eye, with the X-axis parallel to the main outer surfaces oriented horizontally, and the Y-axis parallel to the main outer surfaces and perpendicular to the X-axis; and (c) an image projector configured to project a collimated image from a projector aperture, wherein the collimated image is positioned relative to the optical axis of the image projector. The LOE, image projector, and reflective incoupling surface are arranged such that a collimated image projected from the image projector passes through the transparent wedge, is deflected by reflection at the reflective incoupling surface, propagates in a first direction within the LOE by internal reflection at the main outer surface toward a first region, is redirected by a first progressive deflection configuration, propagates in a second direction within the LOE by internal reflection at the main outer surface toward a second region, and is redirected by a second progressive deflection configuration to outcouple from the LOE toward the user's eye.

[0011] According to further features of one embodiment of the present invention, the transparent wedge is formed from at least two wedge components made of materials having different dispersion properties.

[0012] According to further features of one embodiment of the present invention, at least two wedge components include a first wedge element having two non-parallel surfaces converging toward a first intersection line and a second wedge element having two non-parallel surfaces converging toward a second intersection line, wherein the first wedge element and the second wedge element are oriented such that the first intersection line and the second intersection line are non-parallel.

[0013] According to further features of one embodiment of the present invention, the input plane is perpendicular to the principal ray of the collimated image.

[0014] According to further features of one embodiment of the present invention, the output surface is associated with one of the main outer surfaces via a void or a low refractive index adhesive.

[0015] A further feature of one embodiment of the present invention comprises a first progressive deflection configuration comprising a first set of mutually parallel planar partial reflectors located between the main outer surfaces in a first region of the LOE and having a first orientation, and a second progressive deflection configuration comprising a second set of mutually parallel planar partial reflectors located between the main outer surfaces in a second region of the LOE and having a second orientation that is non-parallel to the first orientation and oblique to the main outer surfaces.

[0016] According to further features of one embodiment of the present invention, a first progressive deflection configuration and a second progressive deflection configuration are implemented as a first diffractive optical element and a second diffractive optical element. [Brief explanation of the drawing]

[0017] The present invention is described herein as an example with reference to the accompanying drawings. [Figure 1] This is a schematic isometric view of an optical system implemented using a light guide element (LOE), constructed and operable according to the teachings of the present invention, for providing a user with an augmented reality near-eye display. [Figure 2A] Figure 1 is a schematic top view of the near-eye display on the user's face, illustrating the angular offset resulting from the device's facial curvature. [Figure 2B] Figure 1 is a side view of the near-eye display on the user's face, illustrating the angular offset resulting from the wide-angle tilt of the device. [Figure 3A] This is a schematic side view of an LOE structure for use in the display of the present invention. [Figure 3B] This is a front view of the LOE structure for use in the display of the present invention. [Figure 3C] This is a top view of the LOE structure for use in the display of the present invention. [Figure 3D] This is a cross-sectional view taken along plane DD in Figure 3B, perpendicular to the second set of partial reflective surfaces. [Figure 4A] This is a side view of an optical assembly (without an image projector) from a first exemplary embodiment of a display, constructed and operable according to the teachings of the present invention. [Figure 4B] This is an isometric view of an optical assembly (without an image projector) from a first exemplary embodiment of a display, constructed and operable according to the teachings of the present invention. [Figure 5A] This is a side view of an optical assembly from an exemplary embodiment of a display alternative, constructed and operable according to the teachings of the present invention. [Figure 5B] This is an isometric view of an optical assembly from an exemplary embodiment of a display alternative, constructed and operable according to the teachings of the present invention. [Figure 6A] This is a side view of an optical assembly from a further exemplary embodiment of a display, constructed and operable according to the teachings of the present invention. [Figure 6B] This is an isometric view of an optical assembly from a further exemplary embodiment of a display, constructed and operable according to the teachings of the present invention. [Figure 6C] This is a side view of an optical assembly from a further exemplary embodiment of a display, constructed and operable in accordance with the teachings of the present invention. [Figure 7A]A schematic side view of an input wedge prism for compensating chromatic aberration, according to one aspect of the present invention. [Figure 7B] A schematic side view of an input wedge prism for compensating chromatic aberration, according to one aspect of the present invention. [Figure 7C] A schematic side view of an input wedge prism for compensating chromatic aberration, according to one aspect of the present invention. [Figure 7D] A view similar to FIG. 4A illustrating a preferred unfolding of the input wedge prism of FIGS. 7A - 7C. [Figure 8A] A first cross-sectional view of a further preferred implementation of an input wedge prism for compensating chromatic aberration, according to one aspect of the present invention, where FIG. 8A is a cross-sectional view taken along line A - A in FIG. 8C. [Figure 8B] A second cross-sectional view of a further preferred implementation of an input wedge prism for compensating chromatic aberration, according to one aspect of the present invention, where FIG. 8B is a cross-sectional view taken along line B - B in FIG. 8C. [Figure 8C] A plan view of a further preferred implementation of an input wedge prism for compensating chromatic aberration, according to one aspect of the present invention, where FIGS. 8A and 8B are cross-sectional views taken along lines A - A and B - B in FIG. 8C, respectively.

Mode for Carrying Out the Invention

[0018] Certain embodiments of the present invention typically provide a display for directing image illumination to an eyebox for viewing by a user's eye, as a head-up display, most preferably a near-eye display, which can be a virtual reality display, or more preferably an augmented reality display.

[0019] Illustrative implementations of a device in the form of a near-eye display, shown overall in 10, according to the teachings of a particular embodiment of the present invention, are schematically illustrated in Figures 1 to 6B. The display uses a light guide optical element (LOE) 100 (interchangeably referred to as a "waveguide," "substrate," or "slab") formed from a transparent material, the transparent material having a set of mutually parallel main outer surfaces 102 and 104 (Figures 2A and 2B), a first progressive deflection configuration associated with the LOE in a first region 110 of the LOE, and a second progressive deflection configuration associated with the LOE in a second region 120 of the LOE.

[0020] LOE100, and more preferably a pair of LOEs for each eye, are supported by a support configuration 106 against the user's head, with one of the main outer surfaces 102 facing the user's eye and oriented relative to the user's eye such that the X-axis parallel to the main outer surface is oriented horizontally. The Y-axis is defined as a direction parallel to the main outer surface 102 and perpendicular to the X-axis.

[0021] The near-eye display 10 also includes an image projector 200 (also referred to herein as “POD”) configured to project a collimated image from the projector aperture. The collimated image includes principal rays (typically the central field of the image’s FOV) that are position-aligned with the optical axis of the image projector.

[0022] To couple the image projected from the image projector 200 to the LOE, a reflective incoupling surface 131 (also referred to as a “mirror”) is provided, as illustrated in the various modifications shown in Figures 4A to 6B. The LOE 100, the image projector 200, and the reflective incoupling surface 131 are arranged such that the collimated image projected from the image projector 200 is deflected by reflection at the reflective incoupling surface 131, incoupled into the LOE 100, and propagated in a first direction within the LOE by internal reflection on the main outer surface toward a first region 110. The image is then reoriented by a first progressive deflection configuration and propagated in a second direction within the LOE by internal reflection on the main outer surface toward a second region 120, and reoriented by a second progressive deflection configuration to outcouple from the LOE toward the user’s eye in the eye movement box 140. Although the device is illustrated in Figure 1 to perform Y-axis scaling first, followed by X-axis scaling, this structure can also be implemented to perform X-axis scaling first, followed by Y-axis scaling, as will be apparent to those skilled in the art.

[0023] According to one aspect of the present invention, the reflective incoupling surface 131 is oriented obliquely with respect to both the X and Y axes. This provides design freedom to achieve a desired initial propagation direction of the incoupled image within the LOE without requiring the image projector to be deployed in a direction that is highly specific to the overall form factor of the device and potentially problematic.

[0024] Therefore, the proposed design, using a high-reflectivity mirror 131, helps to harmonize the waveguide requirements for the angular orientation of the projector with the aesthetically pleasing orientation of the projector. To better understand these requirements, we refer again to Figure 1, which presents a head-mounted display based on a two-dimensional image magnification design. The waveguide 100 consists of two sections 110 and 120, each magnifying the image along a different dimension. The projector 200 projects illumination corresponding to the collimated image that must be coupled into the waveguide. Since the projector has a size that cannot be ignored, especially when a large field of view is required, it is advantageous that the projector may be oriented so that it can be conveniently positioned behind the frame and integrated within the frame.

[0025] The vertical and horizontal tilt of the waveguide 100 imposes additional complexity on the optical mounting requirements, forming a face curvature angle and a wide-angle tilt angle (Figures 2A and 2B). As a result, the waveguide is tilted relative to the line of sight. This tends to induce chromatic aberration due to dispersion. A second aspect of the present invention, complementary to the first aspect, relates to the features of an incoupling configuration that minimizes chromatic aberration, as will be further discussed below.

[0026] Figures 3A-3D show an exemplary structure of a refractive optical element (LOE) waveguide 100 with two-dimensional image magnification based on a partially reflective inner surface. This structure comprises two sets of parallel partially reflective mirrors (facets) embedded in waveguides 111 and 121, located in different regions of waveguides 110 and 120. The angular orientation of each facet can be fully described by its azimuth and elevation angles. The azimuth angle, e.g., angle 112, is the angle between the normal to the facet and the normal to a vector projected onto the waveguide plane that is perpendicular to both the normal to the waveguide and the horizontal line; the elevation angle is the angle between the normal to the facet and the normal to the waveguide (its main outer surface). In an alternative definition, the azimuth angle can be identified as the angle between the intersection of the facet's plane and its main outer surface and the Y-axis. In this specification, the term "azimuth angle" is used to refer to a rotation or orientation about an axis perpendicular to the plane of the main outer surface of the LOE.

[0027] Figures 4A and 4B illustrate a first particularly preferred but non-limiting embodiment of the present invention, in which light projected from the projector 200 (omitted here but shown earlier in Figure 1) enters the aperture 133 of the prism 130, propagates through the input wedge 132, is reflected by the high-reflectivity mirror 131 and coupled into the waveguide. The light is then captured into the waveguide by total internal reflection, propagates through region 110 until it is progressively partially reflected by facet 111 and redirected toward section 120, and finally, the light is progressively partially reflected by facet 121 and projected toward the eye movement box 140 in which the user's eye is positioned.

[0028] It is advantageous to design the angular orientation of the input surface of the input wedge 132 such that the normal to the outer surface is parallel to the central principal ray. In this way, the projector can be directly bonded to the input surface of the input wedge 132. In certain preferred cases, the input wedge 132 is separated from the waveguide by an air gap to eliminate ghosting and enhance aperture filling (ultimately leading to high image uniformity). This can be achieved, for example, by placing 132 directly on the waveguide 100 without adhesive (and if polishing is not exceptionally smooth), or by using an adhesive with a sufficiently low refractive index to maintain internal reflection of the incoupled image at the interface.

[0029] Typically, the elevation angle of mirror 131 is approximately equal to the elevation angle of facet 111, but this is not necessarily required.

[0030] Accordingly, Figures 4A and 4B are examples of embodiments in which the reflective incoupling surface 131 is at least partially provided by the surface of a prism 130 attached to the edge of the LOE. In some cases, as shown herein, the edge surface to which the prism 130 is attached is ground to an entry angle that is non-parallel to the X and Y axes, thereby simplifying the structure of the prism 130 required to produce a correctly oriented incoupling surface 131 that is inclined with respect to both the X and Y axes. In other cases, a more complex prism structure may be used, bonded to an edge surface that is parallel to one of the axes. In alternative implementations, the reflective incoupling surface may be at least partially provided by the surface of a prism optically bonded to one of the main outer surfaces of the waveguide.

[0031] Regarding the size of the image projector aperture and incoupling mirror 131, they can be implemented to be large enough to "fill" the applicant's thickness with image illumination, typically requiring an aperture approximately twice the size of the waveguide aperture. However, in order to minimize the dimensions of the image projector and coupling configuration, it may be preferable to provide a reduced-size projector aperture and coupling configuration that does not achieve waveguide filling. In this case, waveguide filling (and the resulting high uniformity of the output image) can be achieved by including an optical aperture multiplier 138, preferably in the form of a partial reflector deployed between and parallel to the main outer surfaces. An optimal multiplier structure is considered to be a central flat plate partial reflector with 50% reflectivity and 50% transmittance, or a pair of parallel partial reflectors with 33% reflectivity that subdivide the waveguide thickness into three layers of the same thickness. The aperture multiplier may be deployed in the optical path immediately after incoupling, or between the first region 110 and the second region 120, or both, as illustrated herein.

[0032] According to the more particularly preferred features illustrated in the embodiments of Figures 4A and 4B, the reflective incoupling surface 131 intersects with one of the main outer surfaces and is partially within the thickness of the LOE and partially outside the thickness. This allows for a compact design in terms of waveguide thickness dimensions while providing design flexibility to increase the size of the incoupling surface.

[0033] Figures 5A and 5B show modifications of the embodiments of Figures 4A and 4B in which the mirror 131 is limited to the thickness of the waveguide and does not protrude beyond the waveguide. In some cases, this configuration is preferred due to its compact form factor. The structure and operation of this modification are similar to those of Figures 4A and 4B, but it results in incomplete filling of the waveguide, and as a result the aperture multiplier 138 takes on a greater importance.

[0034] Figures 6A and 6B disclose embodiments that are structurally similar to those in Figures 5A and 5B, but here the mirror 131 is integrated into the waveguide structure and generated as a separate facet.

[0035] Figure 6C schematically illustrates a further option in which the reflective incoupling surface 131 is at least partially provided by the surface of a prism 130 mounted on one of the main outer surfaces of the LOE, preferably opposite the input wedge element 132. The first portion of the exemplary input coupled image ray is illustrated here by a line with an arrow.

[0036] As described above, in many preferred implementations, the waveguide 100 has a wide-angle tilt and / or face-curve tilt, as illustrated in Figures 2A and 2B. As a result, the light rays of the image illumination typically enter and exit the waveguide at various angles, and consequently, the image suffers from chromatic aberration due to dispersion at the surface of the substrate glass. According to a further aspect of the present invention, Figures 7A-8C relate to the design of an input wedge prism 132 that reduces these chromatic aberrations. For this purpose, the transparent wedge element 132 is preferably deployed in the optical path between the image projector 200 and the reflective incoupling surface 131, and provides an input surface 134 associated with the projector aperture and an output surface 135 parallel to one of the main outer surfaces of the LOE. The material of the input wedge 132 is selected according to the chromatic aberration in a manner that reduces chromatic aberration. In some cases, to provide an additional degree of freedom for correcting chromatic aberration, the structure 132 includes two or more wedge components made of materials with different dispersion characteristics. By selecting appropriate materials and optimizing the surface angles between materials in 132 (for example, the surface between 132a and 132b), chromatic aberration can be substantially eliminated. Figures 7A-7C illustrate implementations using one, two, and three wedge components 132a, 132b, and 132c, while Figure 7D illustrates an exemplary context in which the input wedge 132 is deployed equivalently to that in Figure 4A, although all of the above embodiments are equally applicable.

[0037] According to certain particularly preferred implementations, the input wedge 132 may use two or more wedge components 132a and 132b oriented at different azimuthal angles, as illustrated in Figures 8A-8C. In other words, at least two wedge components include a first wedge element 132a having two non-parallel surfaces converging toward a first intersection line 137a, and a second wedge element 132b having two non-parallel surfaces converging toward a second intersection line 137b. In this case, the first wedge element 132a and the second wedge element 132b are oriented such that the first intersection line 137a and the second intersection line 137b are non-parallel. This provides an additional degree of freedom for correcting chromatic aberration and is particularly effective for correcting oblique chromatic aberration caused by a combination of face-curve tilt and wide-angle tilt.

[0038] The material selection, the wedge angle of the wedge elements, and the orientation of each wedge element are preferably derived using an optimization process included in standard optical simulation software, as is known in the art. Intersection lines 137a and 137b are illustrated here to simplify the presentation as the edges of the wedges, but it should be noted that in actual implementations, the wedges do not have sharp edges, so the intersection lines between their surfaces are geometric configurations that exist outside the body of the wedge. Furthermore, although two wedges of similar dimensions are illustrated in Figure 8C, for mechanical reasons it is preferable to avoid unsupported protruding corners of the outer wedge. Such overhangs can be avoided by truncating the outer wedge or by making the lower wedge larger.

[0039] In all of the above cases of composite input wedge structures, the structure may be assembled by attaching two well-formed wedge elements, or it may be formed by joining two blocks of corresponding material together and then polishing the outer surfaces to the required angles.

[0040] Alternative methods for reducing chromatic aberration can be used to complement or replace the aforementioned input wedge structure. These include, for example, geometric-phase elements along with high-efficiency color filters (see SPIE conference paper 'Chromatic-aberration correction in geometric-phase lenses, for red, green and blue operation', J. Kim et al, Liquid Crystals XXI (2017)).

[0041] It should be noted that the structure in this embodiment can be applied to either a refractive waveguide or a diffracting waveguide. Accordingly, in a first set of implementations, the first progressive deflection configuration is implemented as a first set of mutually parallel planar partial reflectors 111 located between the main outer surfaces in a first region 110 of the LOE and having a first orientation, and the second progressive deflection configuration comprises a second set of mutually parallel planar partial reflectors 121 located between the main outer surfaces in a second region 120 of the LOE and having a second orientation that is non-parallel to the first orientation and oblique to the main outer surfaces. These configurations are generally similar to those disclosed in the aforementioned PCT Patent Application Publication WO2020 / 049542A1, where further details of preferred implementations of such structures can be found.

[0042] Alternatively, and as is known in the art, the first progressive deflection configuration and the second progressive deflection configuration are implemented as the first diffractive optical element and the second diffractive optical element.

[0043] In one particularly preferred option, as illustrated here, the support configuration 106 is implemented as an eyeglass frame having sides for supporting the device against the user's ears. Other forms of support configurations may also be used, including but not limited to devices suspended from a headband, sun visor, or helmet.

[0044] As described above, the image projector 200 used in the device of the present invention is configured to generate a collimated image, that is, in a collimated image, the light from each image pixel is a parallel beam collimated to infinity in the angular direction corresponding to the pixel's position. Therefore, the image illumination extends to an angular range corresponding to the two-dimensional field of view.

[0045] The image projector 200 can be implemented in various ways, as is known in the art. The image projector typically includes at least one light source deployed to illuminate a spatial light modulator, such as an LCOS chip. The spatial light modulator modulates the projection intensity of each pixel in the image, thereby generating an image. Alternatively, the image projector may include a scanning configuration, typically implemented using a high-speed scanning mirror, in which the intensity of the beam changes pixel by pixel in sync with the motion, while scanning illumination from a laser light source across the image plane of the projector, thereby projecting the desired intensity onto each pixel. In either case, a collimating optical system is provided to produce an output projected image collimated to infinity. Some or all of the above components can be arranged on the surface of one or more polarizing beam splitter (PBS) cubes or other prism configurations, as is known in the art.

[0046] It will be understood that the near-eye display 10 includes various additional components, typically including a controller (not shown) for operating an image projector 200, typically using power from a small onboard battery (not shown) or some other suitable power source. It will be understood that the controller includes all the necessary electronic components, such as at least one processor or processing circuit for driving the image projector, as is all known in the art. These components are applicable to all near-eye displays and are therefore not discussed further herein.

[0047] The above description is intended to serve only as an example, and it will be understood that many other embodiments are possible within the scope of the invention as defined in the attached claims.

Claims

1. A display for directing image illumination to an eye movement box for viewing by the user's eyes, (a) A light guide optical element (LOE) formed from a transparent material, (i) A set of main outer surfaces parallel to each other, (ii) Configuration of a first reflective or diffracting element in a first region of the LOE, which is associated with the LOE and is deployed to progressively deflect light propagating within the LOE, and (iii) A LOE having a configuration of a second reflective or diffracting element in a second region of the LOE that is associated with the LOE and is deployed to progressively deflect light propagating within the LOE, (b) A support configuration configured to support the LOE with respect to the user's head, wherein the X-axis parallel to the main outer surface is oriented horizontally, and the Y-axis is parallel to the main outer surface and perpendicular to the X-axis, such that one of the main outer surfaces faces and is oriented toward the user's eye, (c) An image projector configured to project a collimated image from a projector aperture, wherein the collimated image includes a principal ray aligned with the optical axis of the image projector, (d) Reflective incoupling surface and (e) A transparent wedge element deployed in the optical path between the image projector and the reflective incoupling surface, wherein the transparent wedge element provides an input surface associated with the projector aperture and an output surface parallel to one of the main outer surfaces of the LOE, Equipped with, The LOE, the image projector, and the reflective incoupling surface are arranged such that the collimated image projected from the image projector passes through the transparent wedge element, is deflected by reflection at the reflective incoupling surface, is coupled to the LOE, propagates in a first direction within the LOE by internal reflection at the main outer surface toward the first region, is redirected by the configuration of the first reflecting or diffracting element, propagates in a second direction within the LOE by internal reflection at the main outer surface toward the second region, and is redirected by the configuration of the second reflecting or diffracting element, and is outcoupled from the LOE toward the user's eye. A display in which the transparent wedge element is formed from at least two wedge components made of materials having different dispersion properties, and the collimated image projected from the image projector is transmitted through the at least two wedge components.

2. The display according to claim 1, wherein the reflective incoupling surface is oriented obliquely with respect to both the X axis and the Y axis.

3. The display according to claim 1, wherein the reflective incoupling surface intersects with one of the main outer surfaces and is partially within the thickness of the LOE and partially outside the thickness.

4. The display according to claim 1, wherein the reflective incoupling surface is located between planes defined by the mutually parallel main outer surfaces of the LOE.

5. The display according to claim 1, wherein the at least two wedge components include a first wedge element having two nonparallel surfaces converging toward a first intersection line and a second wedge element having two nonparallel surfaces converging toward a second intersection line, and the first wedge element and the second wedge element are oriented such that the first intersection line and the second intersection line are nonparallel.

6. The display according to claim 1, wherein the input surface is perpendicular to the principal ray of the collimated image.

7. The display according to claim 1, wherein the output surface is associated with one of the main outer surfaces via a void or a low refractive index adhesive.

8. The display according to claim 1, wherein the configuration of the first reflective element comprises a first set of mutually parallel planar partial reflective surfaces located between the main outer surfaces in the first region of the LOE and having a first orientation, and the configuration of the second reflective element comprises a second set of mutually parallel planar partial reflective surfaces located between the main outer surfaces in the second region of the LOE and having a second orientation that is not parallel to the first orientation and oblique to the main outer surfaces.

9. The display according to claim 1, wherein the configuration of the first diffractive element and the configuration of the second diffractive element are implemented as the first diffractive optical element and the second diffractive optical element.

Images