Display method and display structure based on asymmetric effective reflection surface optical waveguide

Abstract

The present invention discloses a display method and display device based on an asymmetric effective reflective surface optical waveguide. The display structure includes a projection optical engine, an optical waveguide with two effective reflective surfaces, an output coupling device, and a control device. The display method guides a light beam composed of fine light rays into the optical waveguide structure in a divergent state. A positive integer K is designed to guide the light emitted by each fine light ray after the Kth reflection in the optical waveguide. The light emitted is modulated by the output coupling device and converged toward the corresponding eyebox, thereby projecting the image information carried by the light beam to the observer's eye. Furthermore, by projecting multiple divergent light beams, a three-dimensional display is ultimately achieved based on Maxwell projection or monocular multi-image technology, overcoming focus-convergence conflicts. The present invention improves display quality by suppressing noise caused by fine light rays exceeding the Kth reflection. Furthermore, combined with the two-dimensional transmission of the divergent light beams within the optical waveguide, the two-dimensional image is projected toward the eyebox corresponding to the observer's pupil.

Description

Technical Field

[0001] The present invention relates to the field of three-dimensional display technology, and more particularly to a display method based on an asymmetric effective reflection surface light waveguide. Background Art

[0002] Compared to two-dimensional displays, three-dimensional displays are gaining increasing attention due to their ability to provide information in the third dimension. Existing three-dimensional displays based on stereoscopic technology rely on binocular parallax. By projecting a corresponding two-dimensional image to each eye of the observer, the intersection of the binocular vision directions with the real scene triggers the brain's depth perception, achieving a three-dimensional visual presentation. During this process, in order to clearly see each corresponding two-dimensional projected image, the observer's eyes must focus on the display surface. This monocular focusing distance differs from the binocular convergence distance corresponding to the intersection of the binocular vision directions (the displayed off-screen scene), resulting in a focus-convergence conflict. In contrast, in a natural environment, when an observer observes a real spatial scene, the monocular focusing distance and binocular convergence distance coincide with the spatial depth of interest. Therefore, the inherent focus-convergence conflict of traditional optical devices that rely solely on binocular parallax for three-dimensional display goes against the naturally evolved physiological habits of the human body, causing visual discomfort for the observer and currently hindering the widespread application of three-dimensional display technology.

[0003] Monocular multi-image (PCT / CN2017 / 080874, THREE-DIMENTIONAL DISPLAY SYSTEM BASEDON DIVISION MULTIPLEXING OF VIEWER'SENTRANCE-PUPIL AND DISPLAY METHOD) and Maxwellian view (US2019 / 0204600, AUGMENTED REALITY OPTICS SYSTEM WITH PINPOINT MIRROR) are two display methods that can solve the focus-convergence conflict problem. They are also called super-multi-view display and retinal projection display, respectively. The former involves projecting at least two two-dimensional projections of the scene to be displayed onto each eye of the observer, so that at least two light beams passing through each display point, along different sagittal directions, impinge on any pupil of the observer. These at least two light beams with different sagittal directions superimpose in space to form a superimposed light spot. When the light intensity distribution at this superimposed light spot has a sufficient pulling advantage relative to the light intensity distributions of the individual light beams on the two-dimensional image display surface, the observer's eyes are naturally drawn to focus on the superimposed light spot, thereby overcoming the focus-convergence conflict. The latter involves projecting only one light beam with a small divergence angle onto each eye of the observer through any display point. This light beam has a small intensity gradient along the transmission direction, so that, through the coupled driving effect of binocular convergence on monocular focus, each eye of the observer is drawn to focus on the displayed scene in space, thereby overcoming the focus-convergence conflict and achieving consistency between the monocular and binocular focus depths. Summary of the Invention

[0004] The present invention proposes a display method based on an asymmetric effective reflective surface optical waveguide. Based on a corresponding thin and lightweight optical structure, this method achieves a three-dimensional display system without focusing-convergence conflicts. This method uses a projection engine to project at least one divergent light beam, constructed from thin light rays carrying optical information, that diverges along at least one dimension. The two asymmetric effective reflective surfaces of the optical waveguide are then used to guide each divergent light beam from the projection engine into an outcoupling device, where it is modulated and converged by the outcoupling device toward the eyebox corresponding to the observer's pupil. In this process, a plane containing at least one incident thin light ray and at least one normal to the optical waveguide's effective reflective surface is designated a vertical plane. A positive integer value K, greater than zero, is designed and selected to guide each thin light ray, after the Kth reflection within the optical waveguide, into the outcoupling device, where it is then modulated and converged toward the corresponding eyebox. A control device sets the optical information carried by each thin light ray to be the projection information of the scene to be displayed along the propagation path of the light ray when it enters the corresponding eyebox. The obvious feature of this display method is that, by designing to suppress the noise caused by more than K reflections of each thin light ray, at least one two-dimensional image is projected to the corresponding pupil of the observer based on an optical waveguide that does not require a light transmission direction deflection structure, so as to achieve a three-dimensional display based on Maxwell projection and / or monocular multi-image to overcome the focus-convergence conflict.

[0005] The present invention provides the following solutions:

[0006] A display method based on an asymmetric effective reflective surface optical waveguide uses a display structure comprising a projection optical engine, an optical waveguide comprising two effective reflective surfaces, an output coupling device, and a control device, including:

[0007] S1. The projection light machine is constructed to be capable of projecting at least one beam of light constructed from thin rays, which is a divergent light beam that is divergent in at least one dimension;

[0008] S2 guides the divergent light beam from the projection light machine to enter the optical waveguide with two effective reflection surfaces as the upper and lower surfaces;

[0009] S3. Select a positive integer K greater than zero and design each thin light line to reflect only K times on the effective reflection surface of the optical waveguide:

[0010] In any vertical section, the area covered by the reflection points where the Kth reflection occurs for all light rays, along the outer edge in the propagation direction of the light rays within the optical waveguide, is designed to be exactly covered by the effective reflection surface where the Kth reflection occurs. The area covered by the reflection points where the K-1th reflection occurs for all light rays, along the outer edge in the propagation direction of the light rays within the optical waveguide, is designed to be exactly covered by the effective reflection surface where the K-1th reflection occurs, where K ≥ 1. The vertical section refers to a surface containing at least one incident light ray and at least one normal to the effective reflection surface of the optical waveguide.

[0011] S4. The thin light emitted by the K-th reflection enters the outcoupling device and is regulated by the outcoupling device and projected into the corresponding eye box;

[0012] S5. The control device controls the projection optical engine to configure each thin light beam to carry information about the projection of the scene to be displayed along the path of the light beam when it enters the corresponding eye box. Furthermore, the thin light beam entering the pupil of the observer within the eye box is designed so that its reverse extension covers the scene to be displayed.

[0013] Each fine light ray undergoes only K+1 reflections at most, or at least some of the fine light rays undergo more than K+1 reflections, but the fine light rays emitted after more than K+1 reflections ultimately do not enter the corresponding eye box, where the pupil of the observer in the eye box can receive at least one light beam passing through any displayed object point.

[0014] In the above scheme, by designing to suppress the noise caused by more than K reflections of each thin light ray, based on the optical waveguide without the need for a light transmission direction deflection structure, at least one two-dimensional image is projected to the corresponding pupil of the observer, so as to achieve a three-dimensional display based on Maxwell projection and / or monocular multi-image to overcome the focus-convergence conflict.

[0015] Furthermore, the display method based on the asymmetric effective reflection surface light waveguide further comprises: extending the light waveguide surface on the surface where the effective reflection surface where the K-1th reflection occurs is located;

[0016] Each fine light ray undergoes at most K+1 reflections, or at least some fine light rays undergo more than K+1 reflections, but the fine light rays emitted after more than K+1 reflections ultimately do not enter the corresponding eye box.

[0017] Furthermore, the display method based on the asymmetric effective reflection surface light waveguide further includes: extending the light waveguide surface on the surface where the effective reflection surface where the K-th reflection occurs is located;

[0018] Each fine light ray undergoes at most K+1 reflections, or at least some of the fine light rays undergo more than K+1 reflections, but the fine light rays emitted after more than K+1 reflections ultimately do not enter the corresponding eye box.

[0019] Furthermore, the display method based on the asymmetric effective reflection surface optical waveguide also includes: providing an auxiliary waveguide body coplanarly connected to the optical waveguide, and reducing the reflectivity of the fine light in the auxiliary waveguide body greater than the Kth reflection by designing the auxiliary waveguide body to have a smaller refractive index value than the optical waveguide.

[0020] Furthermore, the display method based on the asymmetric effective reflection surface light waveguide also includes: designing a coupling-out device with an angle-selective characteristic, wherein for the thin light rays emitted after more than the K+1th reflection, the coupling-out device with the angle-selective characteristic prevents the incident coupling-out, or regulates and guides the light rays to bypass the eye box and propagate.

[0021] Furthermore, the display method based on the asymmetric effective reflection surface light waveguide also includes: when any thin light ray emitted after the K+K'th reflection finally enters the eye box, the reflectivity of this reflection and / or the previous reflection is controlled by coating to reduce the incident light intensity of the thin light ray when it finally enters the corresponding eye box, where K'≧1.

[0022] Furthermore, the display method based on the asymmetric effective reflection surface light waveguide also includes: when any thin light ray emitted after the K+K'th reflection finally enters the eye box, the reflectivity of this reflection and / or the previous reflection is controlled by coating to reduce the incident light intensity of the thin light ray when it finally enters the corresponding eye box, where K'≧1.

[0023] Furthermore, the display method based on the asymmetric effective reflection surface light waveguide also includes: a divergent light beam projected by the projection optical machine, when entering the light waveguide, its each fine light beam or the reverse extension line of each fine light beam intersects at a corresponding spatial point, and the spatial point is named as the equivalent exit point corresponding to the divergent light beam.

[0024] Furthermore, the display structure also includes a pupil tracking unit connected to the control device, and the display method also includes: using the pupil tracking unit to determine the corresponding pupil position in real time, and the control device controls the projection light engine to only activate the projection of part of the divergent light beam according to the real-time position of the corresponding pupil to implement display.

[0025] The present invention also provides the following technical solutions:

[0026] A display structure for implementing the above-mentioned display method based on an asymmetric effective reflection surface optical waveguide is characterized by comprising a projection optical engine, an optical waveguide comprising two effective reflection surfaces, a coupling device and a control device connected to the projection optical engine signal.

[0027] Furthermore, the display structure includes an auxiliary support structure attached to the optical waveguide.

[0028] Furthermore, the connection area between the auxiliary support structure and the waveguide is the surface area before the first reflection occurs in the opposite direction of the reflection and transmission direction of the fine light, or the extended area included in the optical waveguide surface where the fine light undergoes the K-1th reflection and where the K+1th reflection does not occur.

[0029] Furthermore, the projection optical engine includes a display device and a sequential light source group consisting of T light sources that can be turned on sequentially under the control of a control device, wherein the display device that can load information under the control of the control device includes a plurality of pixels or sub-pixels, and the T light sources of the sequential light source group sequentially provide backlight to the display device at T time points in any time period, where T≧2;

[0030] The display device is placed between the sequential light source group and the optical waveguide, that is, before the optical waveguide, or after the optical waveguide.

[0031] Furthermore, the projection light engine includes a display device, a light source providing backlight, and a controllable deflection device capable of deflecting the outgoing direction of incident light under the drive of a control device, and the controllable deflection device sequentially deflects the incident light or outgoing light of the display device to sequentially project multiple divergent light beams;

[0032] The display device is placed between the sequential light source group and the optical waveguide, that is, before the optical waveguide, or after the optical waveguide.

[0033] Furthermore, the display structure includes a phase device and an aperture group consisting of T apertures, wherein the T sequential light sources are respectively converged to the T apertures in the aperture group through the phase device.

[0034] Furthermore, a projection device is provided along the light transmission direction to form an enlarged virtual image for the display device.

[0035] Furthermore, the pixels or sub-pixels of the display device are divided into O pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups modulate O backlights with different characteristics in a one-to-one correspondence and emit corresponding modulated light beams. Each pixel group or sub-pixel group blocks the emission of backlights with other (O-1) non-corresponding characteristics, and each light source is correspondingly composed of O sub-light sources, and the O sub-light sources project backlights with the O orthogonal characteristics, where O≧2;

[0036] The projection light machine turns on O sub-light sources of the light source at each time point, and projects O divergent light beams respectively.

[0037] Furthermore, the projection optical engine includes a display device, a phase device for converging light projected by the display device, and a sequential aperture group consisting of T sequential apertures that can be opened sequentially under the drive of the control device to allow the light beam projected by the display device to pass through, wherein T≧2;

[0038] The T sequential apertures of the sequential aperture group are sequentially opened at T time points in any time period, and the projection light engine sequentially projects divergent light beams using the T sequential apertures as equivalent exit points.

[0039] Furthermore, the projection optical machine includes a display device, a phase device that converges the light projected by the display device, a timing aperture that allows the light projected by the display device to pass through, and a controllable deflection device that can temporally deflect the light emitted from the timing aperture under the drive of a control device. By temporally deflecting the light emitted from the timing aperture through the controllable deflection device, multiple divergent light beams are projected in time.

[0040] Furthermore, the pixels or sub-pixels of the display device are divided into O pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups emit O kinds of light with different characteristics one by one, and any timing aperture is composed of O sub-apertures, and the O sub-apertures allow the O kinds of light with characteristics to pass through one by one, and each sub-aperture blocks the other (O-1) kinds of light with non-corresponding characteristics from passing through, where O≧2.

[0041] Furthermore, the projection optical machine includes a display device constructed by pixels or sub-pixels, a microstructure control device, and an aperture group composed of S apertures. The pixels or sub-pixels of the display device are divided into S pixel groups or sub-pixel groups. The microstructure control device controls the incident light or outgoing light of the display device so that the S pixel groups or sub-pixel groups of the display device project light information to the S apertures respectively, one by one, where S≧2.

[0042] Furthermore, adjacent apertures only allow light with different characteristics to pass through, and the characteristics of the light projected by the pixel group or sub-pixel group corresponding to each aperture are consistent with the characteristics of the light allowed to pass through the corresponding aperture.

[0043] Furthermore, the projection optical machine is a scanning projection unit composed of a scanning device and a modulated light beam generating unit, wherein the light beam emitted by the modulated light beam generating unit is deflected in time by the scanning device to project the light beam in different directions, and the light beam emitted by the modulated light beam generating unit carries corresponding light information under the control of the control device.

[0044] Furthermore, the projection optical engine includes more than one scanning projection unit.

[0045] Furthermore, more than one optical waveguide is stacked and placed, and each optical waveguide corresponds to a corresponding projection optical engine and an outcoupling device.

[0046] Furthermore, each optical waveguide corresponds to a corresponding auxiliary waveguide body.

[0047] The present invention also provides the following technical solutions:

[0048] A display structure for implementing the above-mentioned display method based on an asymmetric effective reflection surface optical waveguide is characterized in that it includes a projection optical engine, an optical waveguide with two effective reflection surfaces as surfaces, a coupling device, a control device connected to the projection optical engine signal, and a one-way converging device, wherein the one-way converging device reduces the divergence of each divergent light beam along the vertical direction of the effective reflection surface before each divergent light beam enters the optical waveguide.

[0049] Furthermore, the display structure includes an auxiliary support structure attached to the optical waveguide.

[0050] Furthermore, the connection area between the auxiliary support structure and the waveguide is the surface area before the first reflection occurs in the opposite direction of the reflection and transmission direction of the fine light, or the extended area included in the optical waveguide surface where the fine light undergoes the K-1th reflection and where the K+1th reflection does not occur.

[0051] Furthermore, the projection optical engine includes a display device and a sequential light source group consisting of T light sources that can be turned on sequentially under the control of a control device, wherein the display device that can load information under the control of the control device includes a plurality of pixels or sub-pixels, and the T light sources of the sequential light source group sequentially provide backlight to the display device at T time points in any time period, where T≧2;

[0052] The display device is placed between the sequential light source group and the optical waveguide, that is, before the optical waveguide, or after the optical waveguide.

[0053] Furthermore, the projection light engine includes a display device, a light source providing backlight, and a controllable deflection device capable of deflecting the outgoing direction of incident light under the drive of a control device, and the controllable deflection device sequentially deflects the incident light or outgoing light of the display device to sequentially project multiple divergent light beams;

[0054] The display device is placed between the sequential light source group and the optical waveguide, that is, before the optical waveguide, or after the optical waveguide.

[0055] Furthermore, the display structure includes a phase device and an aperture group consisting of T apertures, wherein the T sequential light sources are respectively converged to the T apertures in the aperture group through the phase device.

[0056] Furthermore, a projection device is provided along the light transmission direction to form an enlarged virtual image for the display device.

[0057] Furthermore, the pixels or sub-pixels of the display device are divided into O pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups modulate O backlights with different characteristics in a one-to-one correspondence and emit corresponding modulated light beams. Each pixel group or sub-pixel group blocks the emission of backlights with other (O-1) non-corresponding characteristics, and each light source is correspondingly composed of O sub-light sources, and the O sub-light sources project backlights with the O orthogonal characteristics, where O≧2;

[0058] The projection light machine turns on O sub-light sources of the light source at each time point, and projects O divergent light beams respectively.

[0059] Furthermore, the projection optical engine includes a display device, a phase device for converging light projected by the display device, and a sequential aperture group consisting of T sequential apertures that can be opened sequentially under the drive of the control device to allow the light beam projected by the display device to pass through, wherein T≧2;

[0060] The T sequential apertures of the sequential aperture group are sequentially opened at T time points in any time period, and the projection light engine sequentially projects divergent light beams using the T sequential apertures as equivalent exit points.

[0061] Furthermore, the projection optical machine includes a display device, a phase device that converges the light projected by the display device, a timing aperture that allows the light projected by the display device to pass through, and a controllable deflection device that can temporally deflect the light emitted from the timing aperture under the drive of a control device. By temporally deflecting the light emitted from the timing aperture through the controllable deflection device, multiple divergent light beams are projected in time.

[0062] Furthermore, the pixels or sub-pixels of the display device are divided into O pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups emit O kinds of light with different characteristics one by one, and any timing aperture is composed of O sub-apertures, and the O sub-apertures allow the O kinds of light with characteristics to pass through one by one, and each sub-aperture blocks the other (O-1) kinds of light with non-corresponding characteristics from passing through, where O≧2.

[0063] Furthermore, the projection optical machine includes a display device constructed by pixels or sub-pixels, a microstructure control device, and an aperture group composed of S apertures. The pixels or sub-pixels of the display device are divided into S pixel groups or sub-pixel groups. The microstructure control device controls the incident light or outgoing light of the display device so that the S pixel groups or sub-pixel groups of the display device project light information to the S apertures respectively, one by one, where S≧2.

[0064] Furthermore, adjacent apertures only allow light with different characteristics to pass through, and the characteristics of the light projected by the pixel group or sub-pixel group corresponding to each aperture are consistent with the characteristics of the light allowed to pass through the corresponding aperture.

[0065] Furthermore, the projection optical machine is a scanning projection unit composed of a scanning device and a modulated light beam generating unit, wherein the light beam emitted by the modulated light beam generating unit is deflected in time by the scanning device to project the light beam in different directions, and the light beam emitted by the modulated light beam generating unit carries corresponding light information under the control of the control device.

[0066] Furthermore, the projection optical engine includes more than one scanning projection unit.

[0067] Furthermore, more than one optical waveguide is stacked and placed, and each optical waveguide corresponds to a corresponding projection optical engine and an outcoupling device.

[0068] Furthermore, each optical waveguide corresponds to a corresponding auxiliary waveguide body.

[0069] The present invention has the following beneficial effects: It utilizes a waveguide to reflect and propagate a diverging light beam in two dimensions, converging the two-dimensionally distributed light beam onto the eyebox. The waveguide does not require a pupil expansion structure or a light transmission direction deflection structure, potentially enabling scene presentation with monocular depth cues. Light rays that have been reflected more than the designed K times are designed not to enter the corresponding eyebox, thereby suppressing display noise introduced by reflections exceeding K times.

[0070] The details of the embodiments of the present invention are shown in the accompanying drawings and the following description. Other features, objectives and advantages of the present invention will become more apparent through the following description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] The accompanying drawings are used to help better understand the present invention and are also part of this specification. These drawings illustrate the embodiments and together with the description serve to explain the principles of the present invention.

[0072] Figure 1 It is a structural schematic diagram of a display structure based on an asymmetric effective reflection surface light waveguide in Example 1 of the present invention.

[0073] Figure 2 Schematic diagram of a design scheme for optical waveguide surface dimensions in a vertical section in Example 1 of the present invention.

[0074] Figure 3 Schematic diagram of the structure of the concave reflective outcoupling device in Example 1 of the present invention.

[0075] Figure 4 This is a schematic diagram of an example of preparing a holographic grating type outcoupling device in Example 1 of the present invention.

[0076] Figure 5 Schematic diagram of another optical waveguide surface dimension design scheme illustrated in a vertical section in embodiment 2 of the present invention.

[0077] Figure 6 Schematic diagram of another optical waveguide surface dimension design scheme illustrated in a vertical section in embodiment 2 of the present invention.

[0078] Figure 7 It is a schematic diagram of a surface dimension design scheme of the auxiliary waveguide body in Example 2 of the present invention.

[0079] Figure 8 Schematic diagram of another surface dimension design scheme of the auxiliary waveguide body in embodiment 2 of the present invention.

[0080] Figure 9 Schematic diagram of the structure of a one-way converging device taking a cylindrical lens as an example in Example 2 of the present invention.

[0081] Figure 10 Schematic diagram of the reflection and propagation of parallel thin light rays in the optical waveguide in Example 2 of the present invention.

[0082] Figure 11 2 is a structural diagram of a projection optical machine using a sequential light source group in Example 3 of the present invention.

[0083] Figure 12 Schematic diagram of the optical structure of the projection optical machine of the sequential light source group combined with the filtering structure in Example 3 of the present invention.

[0084] Figure 13 Schematic diagram of the projection optical machine structure using a single light source and a controllable deflection device in Example 3 of the present invention.

[0085] Figure 14 Schematic diagram of the projection optical machine structure after the display device is placed in the optical waveguide in Example 3 of the present invention.

[0086] Figure 15 Schematic diagram of the projection optical machine structure using orthogonal characteristic sub-light sources in Example 3 of the present invention.

[0087] Figure 16 Schematic diagram of the projection optical machine structure using a sequential aperture group in Example 3 of the present invention.

[0088] Figure 17 Schematic diagram of the projection optical machine structure using a single timing aperture and a controllable deflection device in Example 3 of the present invention.

[0089] Figure 18 Schematic diagram of the projection optical machine structure using orthogonal characteristic sub-apertures in Example 3 of the present invention.

[0090] Figure 19 Schematic diagram of the projection optical machine structure using a microstructure control device and an aperture group in Example 3 of the present invention.

[0091] Figure 20Schematic diagram of the optical structure of a projection optical machine using a scanning projection unit in Example 3 of the present invention.

[0092] Figure 21 Schematic diagram of the projection optical machine structure using two scanning projection units in Example 3 of the present invention.

[0093] Figure 22 2 is a schematic diagram of an exemplary projection optical machine structure with more than one optical waveguide stack in embodiment 3 of the present invention. DETAILED DESCRIPTION

[0094] The present invention is based on a display method using an asymmetric effective reflective surface optical waveguide. The optical waveguide guides a divergent light beam composed of fine light rays to project a two-dimensional image toward the observer's pupil, thereby realizing the presentation of a freely focusable three-dimensional scene based on a monocular multi-image or / and Maxwell projection method. Furthermore, each fine light ray is designed to be reflected and guided by the optical waveguide and modulated by an outcoupling device so as to enter the observer's pupil along only one path, thereby suppressing and overcoming display noise caused by some fine light rays entering the observer's pupil along more than one path due to more than one reflection.

[0095] Example 1

[0096] Figure 1 The figure shows a basic display structure for implementing a display method based on an asymmetric effective reflective surface optical waveguide, comprising a projection optical engine 10, an optical waveguide 20, a coupling device 30, and a control device 40, wherein the control device 40 is signal-connected to the projection optical engine 10. The projection optical engine 10 projects a divergent light beam composed of thin light rays, such as Figure 1 The example shows two diverging light beams exiting through points S1 and S2. Points S1 and S2 are referred to as equivalent exit points. Any light beam projected by a projection machine may or may not correspond to an equivalent exit point. When an equivalent exit point exists, each fine light ray in the corresponding diverging light beam passes through the equivalent exit point upon entering the optical waveguide 20, or the reverse extensions of each fine light ray in the corresponding diverging light beam pass through the equivalent exit point upon entering the optical waveguide 20. Figure 1 For example, each divergent light beam projected by the optical projection engine 10 has its own corresponding equivalent exit point. Specifically, taking the divergent light beam exiting from the equivalent exit point S1 as an example, it enters the optical waveguide 20, which has two upper and lower effective reflection surfaces: effective reflection surface 201 and effective reflection surface 202. The refractive index n1 of the medium in the optical waveguide 20 is greater than the refractive index n0 of the external medium, allowing each fine light beam to propagate within the optical waveguide 20 by total internal reflection. In fact, if the K value is not too large, the fine light beam can also propagate entirely or partially by non-total internal reflection. Figure 1For example, each light ray propagates by total reflection on the equivalent reflection surface of the optical waveguide 20. A plane including at least one incident light ray and at least one normal line of the effective reflection surface of the optical waveguide is defined as a vertical section, such as Figure 1 The vertical section P containing the thin rays 1 and 2 is shaded with diagonal lines. θ , which is consistent with the reference direction V re The angle is θ. Figure 1 The effective reflection surface of the optical waveguide 20 is taken as a plane, and the reference direction V re Plane P ∥ The plane P is parallel to the effective reflection surface of the optical waveguide 20. ∥ It also includes the equivalent exit point S1. Plane P ∥ It can also coincide with the effective reflection surface 202. The effective reflection surface of the optical waveguide 20 can also be a curved surface in other specific implementation scenarios. θ In the thin light rays incident on the optical waveguide 20 through the equivalent exit point S1, the thin light ray 1 has the minimum reflection angle θ mi Reflection propagation, thin light 2 with the maximum reflection angle θ ma Reflection propagation. Figure 1 In the figure, thin ray 1, thin ray 2 and plane P ∥ The angles are shown as α ma and α mi According to the geometric relationship θ mi +α ma =θ ma +α mi =π / 2. Figure 1 Middle, click P r1 Point P on thin ray 1 r2 Point P on thin ray 2 r3 is a point on the effective reflection surface 202, point P r4 For the straight line P r1 P r2 P r3 On plane P ∥ If P ∥ Coincident with the effective reflecting surface 202, point P r3 and point P r4 After the first reflection of ray 1, the ray is represented as 11, after the second reflection, the ray is represented as 12, and so on; after the second reflection of ray 2, the ray is represented as 21, after the third reflection, the ray is represented as 22, and so on.

[0097] The design selects a positive integer value K greater than zero, and the area occupied by each light ray on a surface of the optical waveguide 20 where the Kth reflection occurs and the area within it is the effective reflection surface area. That is, in any vertical section, the linear area covered by the reflection points where the Kth reflection occurs for all light ray in that vertical section, along the propagation direction of the light ray in that vertical section within the optical waveguide, is exactly covered by the effective reflection surface where the Kth reflection occurs. For simplicity and clarity of the diagram, Figure 1 Taking K=1 as an example, the maximum reflection angle θ on the effective reflection surface 201 where the K=1th reflection occurs is ma The reflection point when the K=1th reflection of the corresponding thin light ray 2 is point P 21 , which is the effective reflection surface 201 at the vertical section P θ Inward, along the light transmission direction x θ The outermost point M θK Similarly, all such outermost points in each vertical section form the outer edge of the effective reflection surface 201 along the light reflection transmission direction, such as Figure 1 The outer edge M u2 P 21 M u3 In other words, the point where the outer edge of the effective reflecting surface where the K-th reflection occurs is within any vertical section is the outermost point of all the fine light rays within the vertical section when the K-th reflection occurs. In the embodiment, such an edge of the effective reflecting surface can be a straight line or a curve. Then the boundary line of the effective reflecting surface 201 where the K-th reflection occurs is at Figure 1 Shown in The outer edge of another effective reflection surface is based on a similar method: in any vertical section, the outermost reflection point of all the fine light rays when the (K-1)th reflection occurs is the outer edge point of the effective reflection surface in the vertical section. Figure 1 In the equation, K=1 corresponds to K-1=0. At this time, any vertical section P θ The maximum reflection angle corresponds to the reflection point when the thin light ray has (K-1)=0 reflections, which is meaningless. In this special case, the area with an effective reflection surface of 202 is designated as the area where no reflection occurs (or where 0 reflections occur), for example Figure 1 As shown, the vertical section P θ The outer edge point of the inner effective reflection surface 202 is point P 12 Among them, point P 12 The point where the thin light ray with the minimum reflection angle first reaches the effective reflection surface. The outer edge of the effective reflection surface 202 can be determined based on the same principle. Correspondingly, the boundary line of the effective reflection surface 202 is Figure 1 Shown in The more general case is K>1, in which case K-1 is not zero. The effective reflection surface where the K-1th reflection occurs has its outer edge at a point within any vertical section, which is the outermost point of all fine light rays within the vertical section when the K-1th reflection occurs. All fine light rays entering the optical waveguide 20 through the equivalent exit point S1, after the Kth reflection, enter the coupling device 30 and are regulated by the coupling device 30 to converge to the convergence point S'1. Similarly, all fine light rays of any other divergent light beam projected by the projection optical machine 10, after the Kth reflection on the effective reflection surface of the optical waveguide 20, are regulated by the coupling device 30 to converge to other corresponding convergence points. The light beam emitted after the K-th reflection, which enters the outcoupling device 30 and is regulated by the outcoupling device 30 to converge to the corresponding convergence point, is called the effective light beam; the other light beams from the light beam projected by the projection light engine 10 and exiting the optical waveguide 20 after no less than the K-th reflection are called invalid light beams. There may also be more than one invalid light beam from the same light beam projected by the projection light engine 10. For example Figure 1 All the fine rays of the divergent light beam emitted through the equivalent exit point S2 converge to another corresponding convergence point S'2. The area occupied by all the convergence points forms an eye box. The characteristic of the eye box is that the pupil of the observer located in the eye box can receive at least one effective light beam passing through any display object point. The "fine rays" described in this patent are not "lines" in the strict sense. The characteristic of each "fine ray" is that it guides and modulates the corresponding effective light beam incident on the eye box through the optical waveguide 20 and the coupling device 30. On the pupil, its light intensity is not less than 1 / 2 of the maximum light intensity value of the light distribution linearity, and is not greater than 1 / 2 of the observer's pupil diameter. The control device 40 controls the projection optical machine 10 to load light information to any fine ray: the projection information of the effective light beam incident on the corresponding eye box along which the scene to be displayed is incident. Then, with Figure 1 The display structure shown is used as a single eyepiece, and two such eyepieces are used to build a binocular display structure. Based on the above method, a three-dimensional display that overcomes the focusing-convergence conflict can be achieved based on Maxwell projection and / or monocular multi-images. Figure 1 If the structure shown is designed to project a display scene to the observer's two eyes separately, multiple convergence points are required to form two eye boxes corresponding to the observer's two eyes.

[0098] It should be pointed out that Figure 1 The area of the effective reflection surface of the optical waveguide 20 shown in the figure is only the area corresponding to the divergent light beam emitted from the equivalent exit point S1. In the case where the projection optical engine 10 projects multiple divergent light beams, the area of each effective reflection surface of the optical waveguide 20 should be the union of the areas determined by the above method for all the divergent light beams projected by the projection optical engine 10. At the same time, Figure 1 The coupling device 30 in FIG. 1 is shown only in FIG. 1 and FIG. 1 is shown in FIG. 1 . θThe intersection lines of all vertical sections can be used to construct the distribution area of the outcoupling device. It is also worth noting that Figure 1 The coupling device 30 shown also only considers the incident light rays emitted from the equivalent exit point S1 and then emitted after the K-th reflection. When the projection optical engine 10 projects multiple diverging light beams, the size of the coupling device 30 should allow the incidence of all fine light rays emitted from each diverging light beam after the K-th reflection. Figure 1 In the example, the thin rays of each divergent beam are illustrated as passing through their respective corresponding equivalent exit points (such as Figure 1 The incident light enters the optical waveguide 20 and is reflected by the effective reflection surface of the optical waveguide 20 for the Kth time, and then is converged by the outcoupling device to the corresponding convergence points (such as Figure 1 Points S'1 and S'2 in the figure). In fact, the fine light rays of each divergent light beam may not have a corresponding equivalent exit point before entering the optical waveguide 20, or / and the fine light rays emitted after the K-th reflection from the effective reflection surface of the optical waveguide 20 do not have a corresponding convergence point after being modulated by the outcoupling device. At this time, the fine light beam emitted after the K-th reflection, which is regulated by the outcoupling device 30 along a unique target direction to enter the corresponding eye box, is a valid light beam; the other light beams from the fine light beam projected by the projection optical engine 10, which exit the optical waveguide 20 after no less than the K-th reflection, are invalid light beams. As long as the "observer pupil located in the eye box can receive at least one valid light beam passing through any display object point" is satisfied, display can be implemented. Among them, if there is only one effective light beam incident on any pupil of the observer through each display object point, it will be displayed based on the principle of Maxwell projection; if there is more than one effective light beam incident on any pupil of the observer through each display object point, it will be displayed based on the principle of monocular multiple images; if for any pupil of the observer, there is only one effective light beam incident on some display object points, and more than one effective light beam incident on the remaining display object points, it will be displayed based on a hybrid mechanism of Maxwell projection and monocular multiple images.

[0099] In the above process, after the K value is determined, it is required that all the light rays emitted by the light rays after the Kth reflection enter the outcoupling device 30. Figure 1 As shown in the figure, when K=1, the thin light ray 1 with a smaller reflection angle is emitted after K=1 reflections. The thin light ray 11 is emitted at point P. 12 The effective light beam 1'1 is coupled out through the coupling device 30. Then the thin light beam 11 corresponds to the light information, which is the projection information of the scene to be displayed along the path of the effective light beam 1'1. But at the same time, the thin light beam 11 at point P 12 It may also be further reflected. That is, through the point P on the outcoupling device 30 12 The K+1=2nd reflection and point P on the effective reflection surface 201 13After the K+2=3rd reflection, the effective light beam 1'1 is incident on the outcoupling device 30 again as a thin light beam 13, and is coupled out as an invalid light beam 1'3 by the outcoupling device 30. When the invalid light beam 1'3 enters the eye box, the projection information of the scene to be displayed along the path of the effective light beam 1'1 carried by the invalid light beam 1'3 will exist as a noise light beam 1'3. Figure 1 In the figure, l1 is the value at point P after K=1 reflections. 14 The thin light beam incident on outcoupling device 30 is modulated by outcoupling device 30, and the outgoing effective beam l'1, carrying the correct optical information, propagates to convergence point S'1. If the angle β between outcoupled beam 1'3 and effective beam l'1 is designed to be sufficiently large, the outcoupled beam can bypass the eyebox without affecting display quality, thus avoiding the formation of a noise beam. Figure 1In the figure, the outcoupling device 30 is exemplified as a transmissive device, that is, the effective light beam coupled out by the outcoupling device 30 and the incident light corresponding to the effective light beam are located on both sides of the outcoupling device 30. The outcoupling device 30 may also be a reflective device, that is, the effective light beam coupled out by the outcoupling device 30 and the incident light corresponding to the effective light beam are located on the same side of the outcoupling device 30. When a fine light beam enters the outcoupling device 30, the light emitted from the outcoupling device 30 includes a light beam that is ultimately emitted as an effective light beam, and may also include a light beam that is ultimately emitted as an invalid light beam; wherein the light beam that ultimately exits the optical waveguide 20 as an invalid light beam may be emitted through reflection from the outcoupling device 30, or may be emitted through diffraction from the outcoupling device 30. Among them, the incident light at a certain point on the outcoupling device 30 may emit more than one outgoing light beam that ultimately forms a noise light beam through the outcoupling device 30. It should be noted that for a fine light beam emitted from a point on the outcoupling device 30 after reflection, which ultimately forms a noise beam, that point is considered its reflection point. For a fine light beam emitted from a point on the outcoupling device 30 after diffraction modulation, which ultimately forms a noise beam, that point is not considered its reflection point, but is referred to as a pseudo-reflection point for ease of description. For this type of noise beam caused by the (K+K')th reflection, the following three treatment options are provided to suppress the noise beam, where K' ≥ 1. ①. Redesign the relevant parameters of the optical structure, including the K value, the reflection angle of each fine light ray, the thickness e of the optical waveguide, the distance a between the equivalent exit point and the effective reflection surface where the first reflection occurs, etc., to avoid each fine light ray from experiencing more than the Kth reflection, or even if more than the Kth reflection occurs, the light emitted by the reflection greater than the Kth will not enter the eye box after being coupled out by the coupling device 30; or even if more than the Kth reflection occurs, and the light emitted by the reflection greater than the Kth will partially or completely enter the eye box after being coupled out by the coupling device 30, the light intensity entering the eye box is not sufficient to cause an impact on the display quality beyond the allowable range. ②. Design an outcoupling device 30 with angular selectivity. Light emitted after more than the Kth reflection is not allowed to be coupled out through the outcoupling device 30. Alternatively, although it is allowed to be coupled out through the outcoupling device 30, the coupled light bypasses the corresponding eyebox and propagates. Alternatively, although it is allowed to be coupled out through the outcoupling device 30 and the coupled light eventually enters the corresponding eyebox, its incident intensity is insufficient to affect the display quality beyond the allowable range. ③. Coating the surface of the optical waveguide 20 and / or the outcoupling device 30. When the fine light beam emitted after the K+K'th reflection eventually forms a noise beam, the coating is designed to reduce the intensity of the noise beam by designing the reflectivity of the K+K'th reflection and / or the previous reflection. In this patent, when a thin light ray emitted by a certain reflection greater than the Kth time enters the corresponding eye box through the coupling device 30, but its intensity entering the eye box is not sufficient to cause an impact on the display quality beyond the allowable range, it is equivalently considered that the thin light ray emitted by this reflection "ultimately does not enter the corresponding eye box."The design objective of this patent is to require that each fine light ray projected by the projection optical engine 10, through reflection and guidance by the asymmetric effective reflection surface of the optical waveguide 20, enter the observer's pupil only once at most (wherein, if a fine light ray emitted after a certain reflection greater than the Kth time enters the observer's pupil through the coupling device 30, but its intensity entering the eye box is not sufficient to cause an impact beyond the allowable range on the display quality, it is equivalently considered that the fine light ray emitted after this reflection "ultimately does not enter the observer's pupil"). This also means that when each fine light ray undergoes greater than the designed K reflections, not all fine light rays from any divergent light beam projected by the projection optical engine 10 ultimately enter the corresponding eye box. Instead, only the fine light rays emitted after the Kth reflection are modulated and guided to the corresponding eye box. Figure 1 In the example, the divergent light beams projected by the optical projection engine 10 have corresponding equivalent exit points. When each divergent light beam does not have a corresponding equivalent exit point, the outermost reflection point where a thin light ray from the same divergent light beam undergoes the Kth reflection within each vertical section may not have the maximum reflection angle corresponding to the thin light ray.

[0100] Figure 1 Only the case of K=1 is given as an example. In this case, the maximum reflection angle θ corresponding to each light ray in a vertical section is ma and the minimum reflection angle θ mi When the difference is large, reflections greater than the Kth may occur on both the outcoupling device 30 and the effective reflection surface. When K>1, reflections greater than the Kth may also occur. At the same time, the outcoupling device 30 requires a carrier to be fixedly placed relative to the optical waveguide 20. On the premise of designing the carrier, it is necessary to further consider the possible reflections greater than the Kth of each fine light ray introduced by the carrier. The following describes, based on a specific example of the outcoupling device 30 carrier, a method for suppressing the noise beam caused by the fine light rays emitted after greater than the Kth reflection of each fine light ray, and then modulated by the outcoupling device 30 to enter the eye box.

[0101] Figure 2 Take K = 2 and a divergent beam from an equivalent exit point S1 as an example, at the vertical section P θ In FIG. 1 , a light waveguide structure for implementing the display method is shown. θ In the thin light beam that enters the optical waveguide 20 through the equivalent exit point S1, 1 is the corresponding minimum reflection angle θ mi The incident light ray, 2 is the corresponding maximum reflection angle θ ma The effective reflection surface 201 of the optical waveguide 20 where the K-1=1st reflection occurs is along the light transmission direction x θ The outcoupling device 30 is prepared or placed on the surface of the optical waveguide including the effective reflection surface 201 and the extension surface. The effective reflection surface 202 of the optical waveguide 20 where the K=2nd reflection occurs is not extended. Figure 1 The optical waveguide structure shown is similar to Figure 2 The optical waveguide shown (where the effective reflection surface for the K-1=1st reflection is extended) is different in that Figure 1 Corresponding to K=1. Figure 2 The following example illustrates the re-reflection of a light ray incident on the outcoupling device 30 after ≥K reflections. The outcoupling device 30 may have a different reflection angle than the reflection angle (which may be the total reflection angle) of the incident light ray on the effective reflection surface. 11 、P 12 、P 13 ,…, respectively refer to the reflection points where the thin light 1 undergoes the first, second, third,… reflections; point P 21 、P 22 ,... respectively refer to the reflection points where the 1st, 2nd,... reflections of the fine light ray 2 occur. The first subscript of each reflection point corresponds to the name of the fine light ray, and the second subscript corresponds to the serial number of the reflection times. The fine light rays emitted by the fine light ray 1 after the 1st, 2nd, 3rd,... reflections are respectively identified as 11, 12, 13,...; the fine light rays emitted by the fine light ray 2 after the 1st, 2nd, 3rd,... reflections are respectively identified as 21, 22, 23,.... In the names of the fine light rays emitted after each reflection, the first subscript corresponds to the name of the fine light ray (for example, incident fine light rays 1, 2), and the second subscript corresponds to the serial number of the reflection times. The above naming method is applicable to the following part of this embodiment and will not be repeated here. Under this naming rule, if only the incident light of a beam of divergent light is considered, at the vertical section P θ Inside, the outer edge points of the two effective reflection surfaces of the optical waveguide 20 are P 2K and P 2(K-1) For example, when K=2, Figure 2 Median vertical section P θ The outer edge points P of the two effective reflection surfaces 22 and P 21 The two effective reflection surfaces of the optical waveguide 20 have different sizes, which is also referred to as the "asymmetric effective reflection surface optical waveguide" in this patent. At the same time, the surface of the optical waveguide 20 carrying the outcoupling device 30 is different from the surface of the optical waveguide 20 in the vertical section P. θ The outer edge points inside are marked with M θK- Indicates that the outer edge of another face is represented by M θK Indicated by. Where the subscripts θ and K represent the vertical section P θ The outer edge point of the optical waveguide surface where the Kth reflection occurs, the subscript θK- represents the vertical section P θThe outer edge point of the optical waveguide surface where the K-1th reflection occurs. It should be noted that, considering the incidence of more than one divergent light beam, the outer edge point of each effective reflection surface in a vertical section needs to be determined by the outermost reflection point when all fine light rays in the vertical section occur the Kth or K-1th reflection. When each effective reflection surface of the optical waveguide 20 is extended, the reflection occurring on each extended area needs to be suppressed, or the outgoing fine light rays need to be designed to bypass the corresponding eye box after being emitted through the coupling device 30. In contrast, each reflection that occurs on the effective reflection surface is no more than the Kth, and optimally it is a reflection with high reflectivity, such as total reflection. According to the aforementioned principle for determining the effective reflection surface area, in the case of the incidence of a divergent light beam that only passes through the equivalent exit point S1, the vertical section P θ The effective reflection surface 201 is along the light transmission direction x θ The edge point of the direction corresponds to the maximum reflection angle θ ma The reflection point P where the thin light ray 2 undergoes K-1=1 reflections 21 ; The effective reflection surface 202 along the light transmission direction x θ The edge point of the direction corresponds to the maximum reflection angle θ ma The reflection point P where the thin light ray 2 undergoes K=2 reflections 22 In order to modulate all incident light rays after the K=2th reflection, the two edge points of the outcoupling device 30 correspond to the minimum reflection angle θ mi The thin light 1 and the corresponding maximum reflection angle θ ma The reflection point P when the thin light ray 2 undergoes the K+1=3rd reflection 13 and P 23 If the extension surface of the effective reflection surface 201 is designed to include the outcoupling device 30, the outer edge point M of the optical waveguide surface with the extension surface θK - and an outer edge point P of the outcoupling device 30 prepared on the surface 23 Coincident, no extension surface of the optical waveguide surface outer point M θK and the edge point P of the effective reflector on the surface 22Overlap. When the projector 10 projects more divergent light beams, the edge points of the above-mentioned coupling device 30 may change accordingly to ensure that the fine light rays projected by the projector 10 after the K-th reflection all enter the corresponding coupling device 30. In the following part of the embodiment, only the case where a beam of divergent light beam is incident on the optical waveguide 20 is used as an example for explanation, and the edge points of the effective reflection surface and the edge points of the coupling device 30 are determined only based on the fine light rays of the divergent light beam, and no similar additional explanation is given for the case where more than one divergent light beam is incident. It should be noted that in the above process, the same K value is taken in different vertical sections. In fact, in order to obtain a regularly shaped beam exit area on the coupling device 30, the maximum reflection angle and the minimum reflection angle corresponding to the fine light rays of the same divergent light beam in each vertical section may be different; different K values may also be selected for the fine light rays of the divergent light beam in different vertical sections. At this time, the surface of the optical waveguide can be divided into different areas, each area corresponds to the same K times, and each area can be processed according to the above rules based on its own K value. Figure 2 In the example, the light beam that enters the outcoupling device 30 after ≧K reflections may also be emitted by diffraction (rather than reflection) and eventually form an invalid light beam. Figure 2 In (c), point P 13 The emitted thin light ray 13 may also be emitted based on the diffraction of the outcoupling device 30. In this case, point P 13 It is no longer the K+1=3rd actual reflection point, but point P 14 This is the K+1=3rd actual reflection point, that is, the thin light ray I4 is formed after the K+K'=2+1=3rd reflection. But for the convenience of explanation, point P 13 is the pseudo-reflection point P 13 The outgoing fine light ray 13 is called the fine light beam emitted after the third pseudo-reflection. The subscripts of the outgoing fine light rays 13 and 14 represent the corresponding number of reflections including the pseudo-reflection. Figure 1 In the figure, the coupling device 30 is exemplified as a transmission-type device, in which the incident fine light beam is modulated after the K-th reflection and is emitted from the other side of the corresponding effective light beam; the coupling device 30 can also be a reflection-type device, in which the incident fine light beam is modulated after the K-th reflection and is emitted from the same side of the corresponding effective light beam. When a reflection-type coupling device 30 is used, similarly, an incident fine light beam may eventually form a fine light beam of noise based on reflection emission, or may eventually form a light beam of noise based on diffraction emission. The coupling device 30 can be various micro-nanostructure devices, such as metasurface structures, holographic gratings, Wiener grating structures and other devices. In the various figures of this patent, the coupling device 30 is shown as a surface structure, which is placed coplanar with the surface of the optical waveguide 20. If possible, it may not be placed coplanar with the optical waveguide 20. For example, the coupling device 30 can also be designed as a concave structure that reflects and controls the incident light, such as Figure 3 shown. Figure 3 The situations shown in (a) and (b) are similar to Figure 2 (a) and (b), only the outcoupling device 30 is changed. The outcoupling device with the concave structure modulates the thin rays from each divergent beam and converges them toward the corresponding eye box along their respective corresponding directions, for example Figure 3 The fine light rays from the equivalent diverging point S1 are modulated by the outcoupling device 30 and converged to the convergence point S'1. Obviously, in this case, the equivalent reflection surface 201 is extended along the curved surface. Similarly, in this case, the reflection of each fine light ray greater than the Kth time also causes the appearance of noise, which needs to be suppressed. For example Figure 3 In (b), the thin ray 1 is at point P 13 After the fourth reflection with a value greater than K=2, the emitted light 14 is modulated by the outcoupling device 30 and is reflected at point P. 15 A noise beam is emitted at this location. However, compared to an outcoupling device placed parallel to the optical waveguide, the viewing angle of the modulated output region of this type of curved outcoupling device may be smaller than that of an outcoupling device placed parallel to the optical waveguide. The following example structures all use a planar outcoupling device as an example, but curved outcoupling devices can also be used.

[0102] Figure 2 (a) to (c), corresponding to θ ma -θ mi Gradually increase. Figure 2 (a) Under the designed conditions, the minimum reflection angle θ mi and the maximum reflection angle θ ma The difference is small, satisfying (a+(K+1)e)tan(θ mi )>(a+(K-1)e)tan(θ ma ), each fine light ray does not diverge on the effective reflection surface for more than the Kth reflection. Where e is the thickness of the optical waveguide 20, and a is the distance between the equivalent exit point and the effective reflection surface where the first reflection occurs. In other words, by designing a, e, θ ma -θ mi The value of (a+(K+1)e)tan(θ mi )>(a+(K-1)e)tan(θ ma ) to avoid more than K reflections on the effective reflection surface. ma -θ mi The value increases, when (a+(K+1)e)tan(θ mi )≦(a+(K-1)e)tan(θ ma ), the thin light beam may be reflected more than K times, and the light emitted by the reflection may enter the outcoupling device 30. Figure 2 (b) In the example, the coupling device 30 is connected to the point P 13The thin light ray 13 emitted by the K+1=3rd reflection passes through point P on the effective reflection surface 202. 14 The K+2=4th reflection emits a thin light ray 14. The thin light ray 14 is at point P 15 If the optical structure parameter design can ensure that the light ray 14 modulated by the outcoupling device 30 does not enter the eye box, then the light ray 14 that is reflected and emitted after the K+2=4th time will not introduce noise. Otherwise, it will introduce noise. Similar situations exist for other light beams that are emitted after more than the designed Kth reflection. When the minimum reflection angle θ mi and the maximum reflection angle θ ma The difference is relatively large, that is, (a+(K-1)e)tan(θ ma ) is much larger than (a+(K+1)e)tan(θ mi ) Figure 2 As shown in (c), some of the thin light rays will be reflected more than K times on the outcoupling device 30 and the effective reflection surface 202. For example, the thin light 1 passes through point P on the outcoupling device 30. 13 The light ray 13 emitted by the K+1=3rd reflection passes through point P on the effective reflection surface 202. 14 The light ray 14 emitted by the K+2=4th reflection passes through point P on the outcoupling device 30. 15 The light ray 15 emitted by the K+3=5th reflection passes through point P on the effective reflection surface 202. 16 The light ray 16 emitted by the K+4=6th reflection passes through point P on the outcoupling device 30. 17 The light ray 17 emitted by the K+5=7th reflection passes through point P on the effective reflection surface 202. 18 The fine light ray 18 emitted by the K+6=8th reflection. At this time, at a certain point on the outcoupling device 30, the fine light ray emitted after the Kth reflection and the fine light ray emitted after more than the Kth reflection are incident at the same time. If the angle between them is not large enough, the fine light ray emitted after more than the Kth reflection and the light beam coupled out by the outcoupling device 30 will enter the eye box as a noise beam. Here, Figure 2 (c) Midpoint P 15Taking the incident fine light 14 as an example, when the angle between it and the fine light 32 incident on this point after the K=2th reflection is less than a certain value, the fine light 14 is modulated and coupled out by the coupling device 30 again, and will enter the eye box as a noise beam. To suppress this type of noise beam, the modulation characteristics of the coupling device 30 can be designed, and the coupling efficiency of the incident fine light beam after more than the Kth reflection is zero, or very low, so that the noise beam finally formed by the fine light beam emitted by this reflection has an impact on the target display quality within an allowable range; or for the incident fine light beam after more than the Kth reflection, guide its corresponding invalid beam not to enter the corresponding eye box. Another method is to suppress this type of noise by coating the surface of the optical waveguide. Regarding the coating of the surface of the optical waveguide, specifically Figure 2 The optical structure shown is illustrated as follows.

[0103] For any light beam emitted after the K+K'th reflection, if a noise beam is eventually formed, the reflectivity of the light beam after the K+K'th reflection or / and the previous reflection can be designed by coating to suppress the corresponding noise, where K'≧1. Figure 2 In the figure, the thin ray 12 is at point P 13 The light is coupled out through the outcoupling device 30, but some of its energy is simultaneously reflected as a thin light ray 13. If this thin light ray 13 is reflected with minimal energy loss or totally reflected without energy loss by the effective reflective surface 202, it enters the outcoupling device 30 as a thin light ray 14 with a certain energy. At this point, if the light ray 14 is modulated and coupled out by the outcoupling device 30 as a noise beam and enters the eyebox, and its energy impact on the display quality exceeds the allowable range of the target display quality, it will have a destructive effect on the display. This type of noise beam can be suppressed by coating the surface of the optical waveguide 20. Taking the transmissive outcoupling device 30 as an example, for the K+K'=2+2=4th reflection corresponding to the thin light ray 14, at least one of the fourth and third reflections needs to be avoided (with zero reflectivity) to prevent the occurrence of the thin light ray 14; or the reflectivity of at least one of the reflections needs to be reduced to reduce the intensity of the thin light ray 14, thereby ensuring that the noise introduced by the light ray 14 coupled out of the outcoupling device 30 is within the allowable range of the display quality. Here, the reflectivity of the third and / or fourth reflections is reduced, which can be achieved by coating. For other larger-order reflections, if a noise beam is eventually formed, its reflectivity on the coupling device is expected to have a larger value (optimally, total reflection), and its reflectivity on the reflection surface of the optical waveguide 20 where K reflections occur is expected to have a smaller value, which can be achieved by coating. In this process, the outgoing fine light beam that eventually forms a noise beam emitted from the coupling device 30 is exemplified as reflected emission. The outgoing fine light beam that eventually forms a noise beam emitted from the coupling device 30 may also be diffracted emission. For example, if Figure 2The thin ray 13 in (c) is the diffracted light of the thin ray 12, which then passes through point P. 14 The K+K'=2+1=3th reflection emits a fine light beam 14. If the fine light beam 14 is coupled out of the noise beam by the coupling device 30, the fine light beam 13 can be reduced at point P by coating. 14 The reflectivity at the point of reflection (increasing its transmittance) is used to suppress the noise coupled out of the fine light beam 14 through the outcoupling device 30. If each fine light beam ultimately forms a noise beam after a greater number of reflections, its reflectivity on the outcoupling device is desirably higher, while its reflectivity on the reflective surface of the optical waveguide 20, where the Kth reflection occurs, is desirably lower. The corresponding coating is performed based on this requirement. Similar requirements apply to all fine light beams that ultimately form noise beams and enter the corresponding eyebox after more than the Kth reflection, provided that their corresponding noise beams cause noise exceeding the allowable range. In fact, when a transmissive outcoupling device is used, if the reflectivity of a fine light beam at its K+1st and / or K+2nd reflections is effectively suppressed, the influence of the K+3rd or more reflections (if any) can be disregarded as the outcoupling beam of the outcoupling device, provided that the K+3rd or more reflections no longer introduce noise or the introduced noise is within the allowable range for the target display quality. However, if this is not the case, for the K+3, K+5, K+7, ... reflections occurring on the outcoupling device 30, if the corresponding areas on the outcoupling device 30 are coated, the reflectivity of these reflections not less than the K+3 reflection needs to be increased. For the K+4, K+6, K+8, ... reflections occurring on the effective reflecting surface 202, if the corresponding areas on the effective reflecting surface 202 are coated, the reflectivity of these reflections greater than the K+3 reflection needs to be reduced.

[0104] Differently, when a reflective outcoupling device 30 is used, if any thin light beam undergoes more than the Kth reflection on the outcoupling device 30, and the light beam emitted by the reflection ultimately forms a noise beam, the coating needs to reduce the reflectivity of the reflection, and the reflections greater than the Kth on the other optical waveguide surface are designed to have a higher reflectivity. If the outcoupling device 30 diffracts the outgoing light beam, ultimately forming a noise beam, the diffracted outgoing light beam needs to be reflected with a high reflectivity when it enters the other optical waveguide surface, and the outgoing light reflected with a high reflectivity when it enters the outcoupling device 30 again, is designed to have a low reflectivity, or / and is regulated by the outcoupling device 30 to emit an invalid light beam that does not form a noise beam.

[0105] In the area where the Kth reflection and the reflection greater than the Kth reflection occur simultaneously, such as Figure 2 (c) The coating layer design should be optimized to not significantly affect the reflectivity of reflections no greater than the Kth within this region. Specifically, if the reflectivity of the thin light ray 4 that undergoes the K-1=1th reflection is significantly reduced, some of its energy will be emitted through the outcoupling device 30. If this outgoing light beam enters the eyebox, it will also introduce noise. Therefore, it needs to be designed to bypass the eyebox, or, even if it enters the eyebox, the noise introduced is within the acceptable range of display quality. Similarly, a coating can be applied to the optical waveguide surface that undergoes the Kth reflection to reduce the reflectivity of reflections greater than the Kth on this optical waveguide surface. However, the coating layer design should also be optimized to not significantly affect, or even improve, the reflectivity of reflections no greater than the Kth on this optical waveguide surface, to avoid excessive loss of display brightness or the introduction of noise. Due to the different conditions of the incident fine light rays at each reflection point (for example, the reflection angles corresponding to the incident fine light rays at different reflection points are different; for another example, on the coupling device 30, the first incidence of each fine light ray is optimally designed to be a small reflectivity reflection to improve the coupling efficiency; incidence greater than the first incidence optimally requires a large reflectivity when a transmission-type coupling device 30 is used, and optimally requires a small reflectivity when a reflection-type coupling device 30 is used), the design requirements for the coating film layer are also different; ray tracing can be combined to design the film layer based on the different characteristics of the incident fine light rays at each reflection point, even for film layers whose characteristics vary significantly with the region. On the surface of the optical waveguide 20, reflections no greater than the Kth are optimally designed to be total reflections. Figure 2 In the vertical section shown, M θK- Mark the outer edge of the optical waveguide surface where the K-1th reflection occurs, with M θK Mark the outer edge point of the optical waveguide surface where the Kth reflection occurs. That is, The optical waveguide 20 is cut in the vertical plane P θ A vertical edge within the , which is optimally designed to have high transmittance to avoid noise caused by its reflection. At Figure 2 It is shown as a straight line, but it can also be a broken line, a curve, etc. In the optical structures shown below, there are such vertical edges in each vertical section, and no further discussion will be given.

[0106] The angle-selective outcoupling device 30 does not allow the incident outcoupling of a fine light ray emitted by the K-th reflection to be greater than; or although it allows the incident outcoupling of a fine light ray emitted by the K-th reflection, it can control the emission direction of the outcoupling light beam to ensure that the outcoupling light beam bypasses the corresponding eye box, or reduce the outcoupling efficiency of the fine light ray emitted by the K-th reflection to ensure that the noise it brings does not exceed the range allowed by the target display quality. Specifically, for example, a volume holographic grating prepared based on optical holography has angle selectivity in its diffraction. When the incident angle of the incident light beam deviates to a certain extent relative to the designed incident angle, its outcoupling efficiency drops rapidly, and it can be used as an angle-selective outcoupling device 30. Specifically, Figure 2 Taking the outcoupling grating 30 corresponding to the optical structure shown in (b) as an example, the preparation method based on optical holography is as follows: Figure 4 As shown: From point I S12 The divergent light that starts out and the convergent light that converges to the convergent point S'1 corresponding to the equivalent exit point S1 intersect and interfere with the optical recording medium placed in the spatial area occupied by the outcoupling device 30, and the recorded volume grating serves as the outcoupling device 30. In the case of K = 2, the mirror image of the equivalent divergent point S1 with respect to the effective reflection surface 201 where the first reflection occurs is point I S11 , point I S11 The mirror image of the effective reflection surface 202 where the second reflection occurs is point I S12 During this recording process, from point I S12 The divergent light cannot be replaced by the light distribution emitted from the equivalent exit point S1 and transmitted through the optical waveguide 20 after reflection. If the light distribution emitted from the equivalent exit point S1 and transmitted through the optical waveguide 20 and the light distribution converging to the convergence point S'1 are recorded, the light emitted from the equivalent exit point S1 that undergoes more than K-th reflection is also recorded to form a corresponding grating distribution. Then, during the display process, in the divergent light beam projected by the projection optical engine 10 and passing through the equivalent exit point S1, the fine light rays that undergo more than K reflections, the fine light rays emitted after the K-th, K+1-th, ... reflections, are modulated by the prepared coupling device 30 and converge to the convergence point S'1, thereby forming the noise that this patent is intended to suppress. Another exemplary noise suppression solution is to coat the surface of the optical waveguide 20 with a film. The film layer design can reduce the reflectivity of each thin light ray at the K+1st and / or K+2nd reflections, and even reduce the reflectivity of other reflections greater than the K+3rd (if any) reflections occurring at the outcoupling device 30. To reduce the above noise, it is also desirable that the K+3rd, K+5th, K+7th, ... reflections occurring at the outcoupling device 30 have a higher reflectivity. Specifically, Figure 2Taking (c) as an example, based on ray tracing, the reflection occurrence area that causes the noise is determined on the surface of the optical waveguide 20, and the film structure is designed according to the specific requirements of reflectivity. The film structure may change its characteristics with changes in position.

[0107] Example 2

[0108] Figure 5 Take K = 2 and a divergent beam from an equivalent exit point S1 as an example, at the vertical section P θ Another example of an optical structure for implementing the display method is shown in FIG. θ In the thin light beam that enters the optical waveguide 20 through the equivalent exit point S1, 1 is the corresponding minimum reflection angle θ mi Thin light, 2 is the corresponding maximum reflection angle θ ma The structure includes an auxiliary support structure 60, which is fixed to the optical waveguide through a connection, and the coupling device 30 is fabricated on the auxiliary support structure 60. In the case where the coupling device 30 needs to cover part of the effective reflection surface, the coupling device 30 can be partially fabricated on the effective reflection surface and the other part fabricated on the auxiliary support structure 60. Figure 5 (a) to (c), θ ma -θ mi Gradually increase. Figure 2 The point is, Figure 5 In (a) and (b), the effective reflection surface that produces K-1 reflections can also be along the light transmission direction x θ The optical waveguide 20 is extended, but no more than K reflections occur in the extended area, and the extended area serves as the connection area between the optical waveguide 20 and the auxiliary support structure 60. Figure 4 In (c), both effective reflection surfaces of the optical waveguide are not extended. Figure 5 In (a), design (a+(K+1)e)tan(θ mi )>(a+(K-1)e)tan(θ ma ), no more than K reflections occur on the reflecting surface. Similar to Figure 2 , e is the thickness of the optical waveguide 20, and a is the distance between the equivalent exit point and the effective reflection surface where the first reflection occurs. ma -θ mi As (a+(K+1)e)tan(θ mi )≦(a+(K-1)e)tan(θ ma ), there are thin rays that undergo more than K reflections. mi ) <atan(θ ma ), the outcoupling device 30 will occupy part of the effective reflection surface, such as Figure 4 (c) In this case, the outcoupling device 30 can be connected through the area before the first reflection occurs on the effective reflection surface. Figure 2 Related discussions: Figure 5 In the case shown, the outcoupling device 30 with angle selectivity can be similarly designed, or the noise caused by the reflection of each thin light beam greater than the Kth time can be avoided or suppressed by coating the surface of the optical waveguide and / or coating the outcoupling device.

[0109] Figure 6 Take K = 2 and a divergent beam from an equivalent exit point S1 as an example, at the vertical section P θ In FIG. 1 , another optical structure for implementing the display method is shown. θ In the thin light beam that enters the optical waveguide 20 through the equivalent exit point S1, 1 is the corresponding minimum reflection angle θ mi Thin light, 2 is the corresponding maximum reflection angle θ ma Thin rays of light. And Figure 2 The structure shown differs in that Figure 6 In the structure shown, both effective reflection surfaces of the optical waveguide 20 are extended, and the outcoupling device 30 is prepared on the surface of the optical waveguide 20 where the thin light beam undergoes the K-1th reflection. Figure 6 (a) to (c), θ ma -θ mi Gradually increase. Figure 6 (a) The vertical section P θ On, (a+(K+1)e)tan(θ mi )>(a+(K-1)e)tan(θ ma ), respectively, with P 21 and P 22 On the effective reflection surface of the outer point, no reflection greater than the Kth occurs, but reflection greater than the Kth occurs on each extended surface. Figure 2 , e is the thickness of the optical waveguide 20, and a is the distance between the equivalent exit point and the effective reflection surface where the first reflection occurs. ma -θ mi As (a+(K+1)e)tan(θ mi )≦(a+(K-1)e)tan(θ ma ), more than K-th reflection occurs on the effective reflection surface, such as Figure 6 (b) and Figure 6 (c) is shown. In (a+Ke)tan(θ mi ) <atan(θ ma ), the outcoupling device 30 will occupy part of the effective reflection surface, such as Figure 4 (c) Region. Similar to Figure 2 Related discussions: Figure 6 In the case shown, the outcoupling device 30 with angle selectivity can be similarly designed, or the noise caused by reflections greater than the Kth time of each fine light ray can be avoided or suppressed by coating the optical waveguide surface (including the effective reflection surface and the extension surface).

[0110] Figure 7 The optical structure shown is Figure 2 The optical structure shown is based on the introduction of an auxiliary waveguide body 70, which is coplanarly connected to the upper and lower surfaces of the optical waveguide 20, and the refractive index of the auxiliary waveguide body 70 is smaller than that of the optical waveguide 20, so as to reduce the reflectivity of reflections greater than the Kth order occurring in the auxiliary waveguide body 70. Figure 7 (a) to (c), θ ma -θ mi Gradually increasing, similar to Figure 2 Situations (a) to (c). Figure 7 In (a), (a+(K+1)e)tan(θ mi )>(a+(K-1)e)tan(θ ma ), no more than Kth reflection occurs on the effective reflection surface of the optical waveguide 20. ma -θ mi As (a+(K+1)e)tan(θ mi )≦(a+(K-1)e)tan(θ ma ), more than K reflections may occur on the effective reflection surface. mi ) <atan(θ ma ), the outcoupling device 30 will occupy part of the effective reflection surface, such as Figure 4 (c) Region. Similar to Figure 2 Related discussions: Figure 7 In the illustrated case, a coupling device 30 with angle selectivity can be similarly designed, or a coating can be applied to the surface of the optical waveguide to avoid or suppress noise caused by reflections greater than the Kth time of each thin light ray. Furthermore, each of the coatings can also be further applied to the surface of each auxiliary waveguide. Figure 7 In FIG, the refractive index of the optical waveguide 20 is shown as the same value n1, and the refractive index of the auxiliary waveguide body 70 is shown as the same value n2. In fact, the refractive index of the auxiliary waveguide body 70 can be gradually changed or non-uniform with the spatial position; even the refractive index of the optical waveguide 20 can be gradually changed or non-uniform with the spatial position. For example, Figure 6 The optical waveguide structure shown has a refractive index at the vertical section P θ Inner edge x θThe distribution of the refractive index change can be a step-by-step change of the refractive index, a continuous gradual change of the refractive index, or a combination of the two. The optical waveguide 20 or the auxiliary waveguide body 70 can be made of optical glass, resin, plastic, polymer and other materials, or a combination of these materials. The design of the optical waveguide whose refractive index changes with the spatial position meets the following requirements: when any thin light emitted by the K+K'th reflection eventually forms a noise beam, the reflectivity of this reflection and / or the previous reflection is regulated by coating to reduce the incident light intensity of the thin light on the corresponding eye box. Figure 7 The optical structure shown, Figure 8 In the illustrated optical structure, the effective reflective surfaces are not extended. The two surfaces of the auxiliary waveguide body 70 are directly and coplanarly connected to the two effective reflective surfaces of the optical waveguide 20. This connection can be achieved by gluing, bonding, or any other method. The optimal connection is one that does not affect the incidence of ambient light.

[0111] In the above optical structures, the divergent light beams projected by the projection light machine may also first pass through Figure 9 After passing through the unidirectional converging device 50, the light then enters the optical waveguide 20. The unidirectional converging device 50 compresses the divergence of the divergent light beam in a vertical direction parallel to the effective reflection surface. Figure 8 A cylindrical lens with a long axis O'O" parallel to the effective reflection surface of the optical waveguide 20 is used as a one-way converging device 50. A diverging light beam projected by the projection optical machine 10 through the spatial point S1 is taken as an example, and the O'O" axis is defined as the diverging direction. Due to the introduction of the one-way converging device 50, Figure 9 When the fine rays of the divergent light beam shown in the figure enter the optical waveguide 20 through the one-way converging device 50, the reverse extension lines of the fine rays no longer converge at a certain spatial point, that is, the divergent light beam no longer has a corresponding equivalent exit point. For a divergent light beam without a corresponding equivalent exit point, the effective reflection surface can also be determined as an edge line based on the above rules. After passing through the one-way converging device 50, the fine rays in each vertical section, due to the converging function of the one-way converging device 50 in the vertical direction, enter the optical waveguide 20 with the corresponding maximum reflection angle and minimum reflection angle becoming smaller. In the most extreme case, there is a vertical section, such as Figure 8As shown in the vertical section P0, each fine light ray exits the one-way converging device 50 in parallel within the vertical section. The introduction of the one-way converging device 50 ensures that each divergent light beam projected by the projection optical engine 10 propagates in a two-dimensional direction within the optical waveguide 20. Furthermore, by reducing the divergence of each divergent light beam from the projection optical engine 10 in the vertical direction (vertical to the effective reflection surface of the optical waveguide), the following objectives are achieved: the fine light rays of the same divergent light beam, after the Kth reflection, have a more uniform spacing at the modulated emission point on the outcoupling device 30 along the light transmission direction. In this patent, each fine light ray from the same divergent light beam, after the Kth reflection, at each emission point on the outcoupling device 30, functions as a display pixel, and it is desirable that the fine light rays have relatively good uniformity. The uniformity of the spacing between the emission points of the fine rays of the same divergent light beam on the outcoupling device 30 after the Kth reflection can also be improved by designing different angular spacings between the fine rays in the same divergent light beam, and the corresponding maximum reflection angle and minimum reflection angle in each vertical section, and even the position of the first reflection point of each fine ray on the equivalent reflection surface.

[0112] Figure 10 yes Figure 9 In the vertical section P0 shown, the thin light rays that enter the optical waveguide 20 in parallel after passing through the unidirectional converging device 50 are reflected in the optical waveguide 20 at a reflection angle θ m The outcoupling device 30 just completely receives all the fine light rays emitted by the K-th reflection. At this time, the fine light rays emitted by the K-th reflection do not enter the outcoupling device. However, considering that the projection light engine 10 projects multiple divergent light beams, the size of the outcoupling device 30 needs to be enlarged to receive all the fine light rays emitted by the K-th reflection from all the divergent light beams. At this time, the fine light rays emitted by the K-th reflection may enter the outcoupling device, especially the θ corresponding to each divergent light beam projected by the projection light engine 10. m Let b / cos(θ m ) is close to or even equal to 2etan(θ m ). At this time, it is also necessary to pay attention to the corresponding noise suppression. Where b is the vertical section P0, the reflection angle θ m When the parallel thin light rays enter the optical waveguide 20, the vertical dimension of the light beam formed by the parallel thin light rays along the propagation direction.

[0113] In the figures of Examples 1 and 2 above, the divergent light beam projected by the projection optical engine 10 is shown as directly incident on the optical waveguide 20, or entering the optical waveguide 20 only through the unidirectional converging device 50. In practice, the light beam can also enter the optical waveguide 20 through various guiding optical devices, such as reflectors and prisms that deflect the propagation direction of the incident light. Furthermore, after entering the optical waveguide 20, the light beam can also be guided along a specific reflection angle by the optical waveguide 20's coupling structure (not shown in this patent), such as a reflective surface or diffraction device structure fabricated within the optical waveguide that deflects the transmission direction of the incident light. These are conventional methods in optical waveguide display technology. Although not shown in this patent, those skilled in the art will readily recognize these devices or structures, and their introduction does not create new innovations based on the present invention. It should be noted that the reflections of each fine light beam before the first reflection on the surface of the optical waveguide 20 are not counted as the K reflections described in this patent.

[0114] In the above embodiments, a pupil tracking unit 80 may be further introduced, such as Figure 1 The pupil tracking unit 80 is used to determine the position of the corresponding pupil in real time. The control device 40 controls the projection light engine 10 to activate only part of the corresponding divergent light beam for display based on the real-time position of the corresponding pupil, thereby reducing the requirements for the time division multiplexing of the display structure or the data volume requirements in the case of spatial multiplexing.

[0115] Example 3

[0116] Figure 11 The figure shows an example of a projection light engine 10, which includes a display device 101 and a sequential light source group 102. The sequential light source group 102 is composed of T≧2 light sources, wherein the T light sources can be turned on sequentially under the control of the control device 40. Figure 11 For example, with T = 3 light sources, S1, S2, and S3, the display device 101 includes multiple pixels or sub-pixels, which can be loaded with light information under the control of the control device 40. At T time points in each time period, the T light sources of the sequential light source group 102 are sequentially turned on, and the display device 101 is synchronously loaded with the corresponding light information, thereby achieving the sequential projection of three divergent light beams with the three light sources as the equivalent emission points. Figure 11 Taking a transmissive display device as an example, it can also be a reflective display device. After being reflected by the reflective display device 101, the light from each light source enters the optical waveguide, and the incident light waveguide process can also be guided by a coupling device (common in conventional optical waveguides). Figure 11 The structure shown may further include a phase device 104 and an aperture group 106 consisting of T apertures, such as Figure 12The phase device 104 can form images of T=3 light sources S1, S2, and S3, such as a lens. The T light sources are respectively converged to the T apertures of the aperture group 106 through the phase device 104. The T apertures then play a filtering role, which can constrain the divergence of each thin light beam incident on the optical waveguide 20. The functions of multiple light sources can also be achieved by a controllable deflection device 102. Figure 13 The projector 10 includes a display device 101 and a light source 1020 for projecting backlight. Driven by a control device 40, a controllable deflection device 103 can deflect the direction of incident light. This device is used to sequentially deflect the backlight from the light source 1020, effectively projecting multiple divergent light beams. Figure 13 The display device 101 in the embodiment may be an active light emitting device or a passive light emitting device with a backlight source. Figures 11 to 13 In the embodiment, the display device 101 is placed between the light source and the optical waveguide 20, that is, placed in front of the optical waveguide 20. It can also be placed after the optical waveguide, with the light emitted by the light source, guided by the optical waveguide, and modulated by the outcoupling device 30 as the backlight, as shown in FIG. Figure 14 In this case, the information corresponding to each light beam is loaded by the display device 101 placed after the optical waveguide 20 under the control of the control device 40. Figure 14 The display device 101 shown is a transmissive device, which can also be a reflective device. In addition, a projection device 90 can be further introduced along the light transmission direction to form an enlarged virtual image of the display device 101. Figures 11 to 14 In the optical structure shown, the pixels or sub-pixels of the display device 101 can be divided into O≧2 pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups modulate O backlights with different characteristics one by one, and emit their corresponding modulated light beams. Each pixel group or sub-pixel group prevents the emission of backlights with other (O-1) non-corresponding characteristics. In this case, each light source is designed to be composed of O sub-light sources, and the O sub-light sources project backlights with the O characteristics. The pixels or sub-pixels of the O≧2 pixel groups or sub-pixel groups are optimally arranged intermittently. The O different characteristics should be distinguishable from each other. For example, the pixel corresponding to one characteristic only modulates and emits the incident light with the corresponding characteristic; for the other (O-1) non-corresponding characteristics, the pixel does not allow them to be incident and does not emit modulated light. Linear deflections with mutually perpendicular polarization directions, timing characteristics that are activated at different times, or a combination of the two can be used as the different characteristics. Figure 15 For example, O=2 different characteristics with mutually perpendicular polarization directions are represented by “·” and “-” respectively. Each light source is composed of sub-light sources that emit light of these two characteristics respectively. For example, the sub-light source OS of light source S1 11 and OS 12, respectively emitting “·” light and “-” light. The pixels of the display 101 are divided into O=2 groups, each modulating and emitting only “·” light and “-” light. Specifically, the pixel p nm ,p nm+2 ,…;p n+1m+1 ,p n+1m+3 ,…;…the pixel group only allows the incident “-” light to be modulated and emitted, and blocks the emission of “·”; the pixel p nm+1 ,p nm+3 ,…;p n+1m ,p n+1m+2 ,… The pixel group formed by only allows the incident “·” light to be modulated and emitted, and blocks the “-” light from being emitted. The attached polarizer can be used to realize the “·” and “-” characteristics of each sub-light source, or each pixel, or each sub-pixel. Then, the sub-light sources OS turned on at the same time 11 and OS 12 , its outgoing backlight is modulated by its corresponding pixel group, projecting O = 2 divergent light beams. The sub-light sources corresponding to the other light sources are designed similarly. At T time points, the O = 2 sub-light sources, which are sequentially turned on, can project T × O divergent light beams. This also allows for the case where the projection optical engine 10 only includes O sub-light sources of a sequential light source, corresponding to the case where there is no sequential multiplexing.

[0117] Figure 16 The illustrated projection optical engine 10 includes a display device 101, a phase device 104 that converges the light projected by the display device 101, and a sequential aperture group 105 consisting of T≧2 sequential apertures that can be sequentially opened under the control of a control device 40 to allow the light beam projected by the display device 101 to pass through. As the T sequential apertures are sequentially opened, the display device 101 synchronously loads the light information corresponding to the diverging light beams of the opened sequential apertures, thereby achieving the sequential projection of the T diverging light beams. Figure 16 A lens is used as the phase device 104 , and the sequential aperture group 105 is placed on its focal plane. The sequential aperture group 105 can also be placed on a non-focal plane of the phase device 104 . Figure 16 The display device 101 can be an active light emitting device or a passive light emitting device with its own backlight source. The function of the timing aperture group 105 can also be realized by a timing aperture 1050 and a controllable deflection device 103 for deflecting the propagation direction of the light emitted from the timing aperture 1050, such as Figure 17 The control device 40 drives the controllable deflection device 103 to sequentially deflect the light emitted from the timing aperture 1050 . Under the control of the control device 40 , the display device 101 synchronously loads light information, thereby realizing the projection of multiple divergent light beams to the optical waveguide 20 . Figures 16 and 17In the optical structure shown, the pixels or sub-pixels of the display device 101 can be divided into O≧2 pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups emit O kinds of light with different characteristics one by one. At this time, each timing aperture is designed to be composed of O sub-apertures respectively, and the O sub-apertures respectively have the O characteristics, and each sub-aperture only allows the light of the corresponding characteristics to pass through, and blocks the other (O-1) kinds of light with non-corresponding characteristics. The pixels or sub-pixels of the O≧2 pixel groups or sub-pixel groups are arranged optimally. The O different characteristics should be distinguishable from each other. Linear deflections with mutually perpendicular polarization directions, timing characteristics that are activated at different times, a combination of the two, etc. can be used as the different characteristics. Figure 18 Taking O=2 different characteristics with mutually perpendicular polarization directions as an example, they are represented by “·” and “-” respectively. Each sequential aperture is composed of sub-apertures that allow light of these two characteristics respectively. For example, the sub-aperture A of the sequential aperture A1 11 and A 12 , allowing "·" light and "-" light to pass through respectively. The pixels of the display 101 are divided into O=2 groups, which emit "·" light and "-" light respectively. Specifically, the pixel p nm ,p nm+2 ,…;p n+1m+1 ,p n+1m+3 ,…;…the pixel group composed of them emits “-” light; pixel p nm+1 ,p nm+3 ,…;p n+1m ,p n+1m+2 ,…the pixel group emits “·”. Blocks the emission of “-”. Then, the sub-apertures A opened at the same time 11 and A 12 , allowing the light information projected by two pixel groups to pass through. The subapertures corresponding to the other sequential apertures are designed similarly. Thus, at T time points, O = 2 subapertures sequentially opened can project T × O divergent light beams. This also allows for the case where the projection optical engine 10 only includes O subapertures of a single sequential aperture, corresponding to the case where no sequential multiplexing is used.

[0118] Figure 19 In the embodiment, the microstructure control device 107 is placed corresponding to the display device 101, modulating the propagation direction of the outgoing light or incident light of each pixel or sub-pixel of the display device 101, so that the S≧2 pixel groups or sub-pixel groups of the display device 101 project light information to the S apertures respectively. Figure 19 The projector 10 shown can project S divergent light beams based on spatial multiplexing. Furthermore, adjacent apertures can be designed to allow only light with different characteristics to pass through, and the characteristics of the light projected by the pixel group or sub-pixel group corresponding to each aperture are consistent with the characteristics of the light allowed to pass through the corresponding aperture, so as to reduce information crosstalk between adjacent apertures. Obviously, Figure 19In the structure of the projection optical machine 10 shown, if its display device 101 adopts a backlight device, and its corresponding backlight structure can sequentially incident T beams of backlight along T different directions, the projection of more T×S divergent light beams can be achieved through the combination of spatial multiplexing and temporal multiplexing.

[0119] The function of the projection light engine 10 can also be implemented by the scanning projection unit 108. Figure 20 The scanning projection unit 108 includes a scanning device 1081 and a modulated light beam generating unit 1082. The modulated light beam generating unit 1082 includes R (red), G (green), and B (blue) light sources 1082R, 1082G, and 1082B as an example. The fine light rays projected by them are collectively referred to as a beam of fine light rays through the reflector 1082MR, the half-reflective half-mirror 1082G, and the half-reflective half-mirror 1082B. The synthesized fine light rays are two-dimensionally scanned by the scanning device 1081 to form a divergent light beam projection. Each light source is controlled by the control device 40 and synchronously loads its corresponding information. The scanning projection unit 108 can flexibly adjust the reflection angle corresponding to each fine light ray in any vertical section, including the angular spacing between adjacent fine light rays, which is beneficial for improving the uniformity of the distribution of the exit points of each exit light beam on the coupling device 30 through the flexible adjustment of the angular spacing. The projection optical machine 10 may also further include more than one scanning projection unit, such as Figure 21 Scanning projection units 108 and 108'.

[0120] In addition, the display structure can also be stacked with more than one optical waveguide, such as Figure 22 Each optical waveguide 20 corresponds to a corresponding projection optical engine 10, 10' and an outcoupling device 30, 30'. Figure 22 In FIG. 1 , the optical waveguides 20 and 20 ′ are shown as being each designed with a corresponding auxiliary waveguide body 70 and 70 ′.

[0121] The core concept of this invention is to inject a diverging light beam into an optical waveguide, utilizing the optical waveguide's two-dimensional reflection propagation of fine light rays contained in the incident light beam. Each fine light ray is designed to undergo a preset K reflections, modulated by an output device, and emitted in a two-dimensional distribution from the output device, projecting a two-dimensional image onto the observer's pupil within the eye box. Each fine light ray is designed to have no more than K reflections, or the light beams emitted after more than K reflections are guided away from the eye box to suppress display noise introduced by more than K reflections. This display method, in a thin and lightweight optical structure, can achieve three-dimensional display that overcomes focus-convergence conflicts based on Maxwell projection or monocular multi-image technology. The optical waveguide employed does not require pupil expansion or steering structures, significantly reducing the requirements for the optical waveguide fabrication process.

[0122] The above are only preferred embodiments of the present invention, but the design concept of the present invention is not limited thereto, and any non-substantial modifications made to the present invention using this concept also fall within the scope of protection of the present invention. For example, various existing optical waveguide structures can be used as the optical waveguide of this patent; for example, an existing optical waveguide structure composed of three stacked monochromatic optical waveguides that can project colored light information can also be used. For example, various micro-nano structures that can modulate the emission direction of each pixel or sub-pixel of a display device can be used as the microstructure control device of this patent. For another example, countless other optical structures that can project at least one divergent light beam (including divergent light beams without corresponding equivalent emission points) can be used as the projection light machine of this patent. Accordingly, all relevant embodiments fall within the scope of protection of the present invention.

Claims

1. A display method based on an asymmetric effective reflection surface light waveguide, characterized in that: The display method uses a display structure comprising a projection optical engine (10), an optical waveguide (20) comprising two effective reflection surfaces, an output coupling device (30) and a control device (40), including: S1. The optical projection machine (10) is constructed to be capable of projecting at least one divergent light beam constructed of thin light rays, which is divergent in at least one dimension; S2. guiding the divergent light beam from the projection light machine to enter the optical waveguide (20) with two effective reflection surfaces as the upper and lower surfaces; S3. Select a positive integer K value greater than zero and design each thin light ray to be reflected only K times on the effective reflection surface of the optical waveguide (20): In any vertical section, the area covered by the reflection points where all the fine light rays undergo the Kth reflection is designed to be just covered by the effective reflection surface where the Kth reflection occurs, along the outer edge of the fine light rays in the propagation direction of the light guide (20), and the area covered by the reflection points where all the fine light rays undergo the K-1th reflection is designed to be just covered by the effective reflection surface where the K-1th reflection occurs, along the outer edge of the fine light rays in the propagation direction of the light guide (20), wherein K≧1, and the vertical section refers to a surface including at least one incident fine light ray and at least one normal line of the effective reflection surface of the light guide; S4. The thin light emitted by the K-th reflection enters the coupling device (30) and is regulated by the coupling device (30) and projected to the corresponding eye box; S5. The control device (40) controls the projection light engine (10) to set each thin light beam to carry light information as projection information of the scene to be displayed along the propagation path when the thin light beam enters the pupil of the observer in the eye box, and the thin light beam entering the pupil of the observer in the eye box is designed so that its reverse extension line can cover the scene to be displayed; Each fine light ray undergoes only K+1 reflections at most, or at least some of the fine light rays undergo more than K+1 reflections, but the fine light rays emitted after more than K+1 reflections ultimately do not enter the corresponding eye box, where the pupil of the observer in the eye box can receive at least one light beam passing through any displayed object point.

2. The display method based on an asymmetric effective reflection surface light waveguide according to claim 1, characterized in that: Also includes: The surface of the optical waveguide is extended on the surface where the effective reflection surface where the K-1th reflection occurs; Each fine light ray undergoes at most K+1 reflections, or at least some fine light rays undergo more than K+1 reflections, but the fine light rays emitted after more than K+1 reflections ultimately do not enter the corresponding eye box.

3. The display method based on an asymmetric effective reflection surface light waveguide according to claim 2, characterized in that: Also includes: Further extending the optical waveguide surface on the surface where the effective reflection surface where the K-th reflection occurs; Each fine light ray undergoes at most K+1 reflections, or at least some fine light rays undergo more than K+1 reflections, but the fine light rays emitted after more than K+1 reflections ultimately do not enter the corresponding eye box.

4. The display method based on an asymmetric effective reflection surface light waveguide according to any one of claims 1 to 2, characterized in that: Also includes: An auxiliary waveguide (70) is provided which is coplanarly connected to the optical waveguide (20). By designing the auxiliary waveguide (70) to have a smaller refractive index value than the optical waveguide (20), the reflectivity of the thin light in the auxiliary waveguide (70) that is greater than the Kth reflection is reduced.

5. The display method based on an asymmetric effective reflection surface light waveguide according to any one of claims 1 to 3, characterized in that: The invention also includes: designing a coupling device (30) with an angle selection characteristic, wherein for the fine light rays emitted after more than K+1 times of reflection, the coupling device (30) with the angle selection characteristic prevents the fine light rays from being incident and coupled out, or regulates and guides the fine light rays to bypass the eye box and propagate.

6. The display method based on an asymmetric effective reflection surface light waveguide according to claim 4, characterized in that: The invention also includes: designing a coupling device (30) with an angle selection characteristic, wherein for the fine light rays emitted after more than K+1 times of reflection, the coupling device (30) with the angle selection characteristic prevents the fine light rays from being incident and coupled out, or regulates and guides the fine light rays to bypass the eye box and propagate.

7. The display method based on an asymmetric effective reflection surface light waveguide according to any one of claims 1 to 3, characterized in that: Also includes: When any thin light ray emitted after the K+K'th reflection finally enters the eye box, the reflectivity of this reflection and / or the previous reflection is regulated by coating to reduce the incident light intensity of the thin light ray when it finally enters the corresponding eye box, where K'≧1.

8. The display method based on an asymmetric effective reflection surface light waveguide according to claim 4, characterized in that: Also includes: When any thin light ray emitted after the K+K'th reflection finally enters the eye box, the reflectivity of this reflection and / or the previous reflection is regulated by coating to reduce the incident light intensity of the thin light ray when it finally enters the corresponding eye box, where K'≧1.

9. The display method based on an asymmetric effective reflection surface light waveguide according to claim 1, characterized in that: Also includes: When a divergent light beam projected by a projection optical machine (10) enters an optical waveguide (20), each of its fine light rays or the reverse extension lines of each of the fine light rays intersect at a corresponding spatial point, and the spatial point is named as the equivalent exit point corresponding to the divergent light beam.

10. The display method based on an asymmetric effective reflection surface light waveguide according to claim 1, characterized in that: in, The display structure also includes a pupil tracking unit (80) connected to the control device (40), and the display method further includes: using the pupil tracking unit (80) to determine the corresponding pupil position in real time, and the control device (40) controls the projection light machine (10) to activate only the projection of a portion of the divergent light beam based on the real-time position of the corresponding pupil to implement display.

11. A display structure for implementing the display method based on an asymmetric effective reflection surface light waveguide according to any one of claims 1 to 10, characterized in that: The invention comprises a projection optical engine (10), an optical waveguide (20) comprising two effective reflection surfaces, an output coupling device (30), and a control device (40) connected to the projection optical engine (10) by signal.

12. A display structure for implementing the display method based on an asymmetric effective reflection surface light waveguide according to any one of claims 1 to 10, characterized in that: The invention comprises a projection optical engine (10), an optical waveguide (20) comprising two effective reflection surfaces, an output coupling device (30), a control device (40) connected to the projection optical engine (10) for signal signals, and a one-way converging device (50), wherein the one-way converging device (50) reduces the divergence of each divergent light beam in a direction perpendicular to the effective reflection surface before each divergent light beam enters the optical waveguide (20).

13. The display structure according to claim 11 or 12, characterized in that: It further includes an auxiliary support structure (60) attached to the optical waveguide (20).

14. The display structure according to claim 13, wherein: The connection area between the auxiliary support structure (60) and the optical waveguide (20) is a surface area before the first reflection occurs in the opposite direction of the reflection transmission direction of the fine light, or an extended area included in the surface of the optical waveguide (20) where the fine light undergoes the K-1th reflection and where the K+1th reflection does not occur.

15. The display structure according to claim 11 or 12, characterized in that: The projection optical machine (10) comprises a display device (101) and a sequential light source group (102) composed of T light sources that can be sequentially turned on under the drive of a control device (40), wherein the display device (101) that can load information under the drive of the control device (40) comprises a plurality of pixels or sub-pixels, and the T light sources of the sequential light source group (102) sequentially provide backlight to the display device (101) at T time points in any time period, where T≧2; The display device (101) is placed between the sequential light source group (102) and the optical waveguide (20), that is, before the optical waveguide (20), or after the optical waveguide (20).

16. The display structure according to claim 11 or 12, characterized in that: The projection optical machine (10) comprises a display device (101), a light source (1020) for providing backlight, and a controllable deflection device (103) capable of deflecting the outgoing direction of incident light under the drive of a control device (40), and the controllable deflection device (103) sequentially deflects the incident light or outgoing light of the display device (101) to sequentially project multiple divergent light beams; The display device (101) is placed between the sequential light source group (102) and the optical waveguide (20), that is, before the optical waveguide (20), or after the optical waveguide (20).

17. The display structure according to claim 16, wherein: It further comprises a phase device (104) and an aperture group (106) consisting of T apertures, wherein the T sequential light sources are respectively converged to the T apertures of the aperture group (106) via the phase device (104).

18. The display structure according to claim 16 or 17, characterized in that: A projection device (90) is provided along the light transmission direction to form an enlarged virtual image for the display device (101).

19. The display structure according to claim 16 or 17, characterized in that: The pixels or sub-pixels of the display device (101) are divided into O pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups modulate O backlights with different characteristics one by one and emit corresponding modulated light beams. Each pixel group or sub-pixel group prevents the emission of other (O-1) types of backlights with non-corresponding characteristics, and each light source is composed of O sub-light sources, and the O sub-light sources project backlights with the O orthogonal characteristics, wherein O≧2; The projection light machine (10) turns on O sub-light sources of the light source at each time point, and projects O divergent light beams respectively.

20. The display structure according to claim 11 or 12, characterized in that: The projection optical machine (10) includes a display device (101), a phase device (104) for converging light projected by the display device (101), and a sequential aperture group (105) composed of T sequential apertures that can be opened sequentially under the drive of a control device (40) to allow the light beam projected by the display device (101) to pass through, wherein T≧2; The T sequential apertures of the sequential aperture group (105) are sequentially opened at T time points in any time period, and the projection light engine (10) sequentially projects divergent light beams using the T sequential apertures as equivalent exit points.

21. The display structure according to claim 11 or 12, characterized in that: The projection optical machine (10) comprises a display device (101), a phase device (104) for converging light projected by the display device (101), a timing aperture (1050) for allowing light projected by the display device (101) to pass through, and a controllable deflection device (103) capable of sequentially deflecting light emitted from the timing aperture (1050) under the drive of a control device (40). The controllable deflection device (103) sequentially deflects light emitted from the timing aperture (1050) to sequentially project multiple divergent light beams.

22. The display structure according to claim 20 or 21, characterized in that: The pixels or sub-pixels of the display device (101) are divided into O pixel groups or sub-pixel groups, and the O pixel groups or sub-pixel groups emit O kinds of light with different characteristics in a one-to-one correspondence, and any sequential aperture is composed of O sub-apertures, and the O sub-apertures allow the O kinds of light with different characteristics to pass through in a one-to-one correspondence, and each sub-aperture blocks the other (O-1) kinds of light with non-corresponding characteristics from passing through, where O≧2.

23. The display structure according to claim 11 or 12, characterized in that: The projection optical machine (10) includes a display device (101) constructed by pixels or sub-pixels, a microstructure control device (107), and an aperture group (106) composed of S apertures, wherein the pixels or sub-pixels of the display device (101) are divided into S pixel groups or sub-pixel groups, and the microstructure control device (107) controls the incident light or the outgoing light of the display device (101) so that the S pixel groups or sub-pixel groups of the display device (101) project light information to the S apertures in a one-to-one correspondence, wherein S≧2.

24. The display structure according to claim 23, wherein: Adjacent apertures only allow light with different characteristics to pass through, and the characteristics of light projected by the pixel group or sub-pixel group corresponding to each aperture are consistent with the characteristics of light allowed to pass through the corresponding aperture.

25. The display structure according to claim 11 or 12, characterized in that: The projection optical machine (10) is a scanning projection unit (108) composed of a scanning device (1081) and a modulated light beam generating unit (1082), wherein the light beam emitted by the modulated light beam generating unit (1082) is deflected in time by the scanning device (1081) to project the light beam in different directions, and the light beam emitted by the modulated light beam generating unit (1082) carries corresponding light information under the control of a control device (40).

26. The display structure according to claim 25, characterized in that: The projection light engine (10) includes more than one scanning projection unit (108).

27. The display structure according to claim 11 or 12, characterized in that: More than one optical waveguide (20) is stacked and placed, and each optical waveguide (20) corresponds to a corresponding projection optical engine (10) and an output coupling device (30).

28. The display structure according to claim 27, wherein: Each optical waveguide (20) further corresponds to a corresponding auxiliary waveguide body (70).

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