A near-eye display method and system based on retinal projection

Abstract

The application relates to a near-eye display method and system based on retina projection, and relates to the technical field of augmented reality, which comprises the following steps: generating a first spherical image wave based on a two-dimensional image; performing divergence angle conversion on the first spherical image wave; converting the first spherical image wave with a first divergence angle into a second spherical image wave with a second divergence angle; and converting the second spherical image wave into a third spherical image wave with a third divergence angle, wherein the first spherical image wave and the second spherical image wave are divergence waves, and the third spherical image wave is a convergence wave; the third spherical image wave converges at a retinal point, and a two-dimensional image can be observed at the retinal point; the two-dimensional images of at least two viewpoints of a same three-dimensional scene are converted in a one-dimensional direction twice to generate at least two retinal points into a single human eye, and a three-dimensional virtual image can be observed in the single human eye, so that the vergence-accommodation conflict is eliminated.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of augmented reality technology, and in particular to a near-eye display method and system based on retinal projection. BACKGROUND

[0002] In recent years, augmented reality (AR) technology has developed rapidly, but the mainstream technical solution still has deficiencies in three-dimensional display. The virtual image projected by the mainstream augmented reality optical display solution is on a fixed depth plane, and the three-dimensional stereoscopic effect perceived by the human eye is caused by the parallax of the images output to the left and right eyes. Such a way will cause the vergence accommodation conflict of the human eye, and long-term wearing of such products will cause discomfort and adverse reactions such as dizziness and nausea. To solve this problem, a monocular depth cue needs to be introduced.

[0003] Retinal projection display is based on Maxwell's observation method. Since the light beam entering the human eye is fine, the human eye can clearly see the image within a large depth of field. When the human eye focuses and the binocular convergence vergence observes natural real objects of different distances, the virtual image can be clearly displayed independently of the focusing of the lens, thereby avoiding the vergence accommodation conflict. However, the retinal projection technology still has two shortcomings. First, the convergence point of the fine light beam matches the pupil of the human eye, so the range of movement of the human eye is small. Second, the retinal projection technology can enable the virtual image to be clearly displayed independently of the focusing of the lens, but it does not provide a monocular depth cue.

[0004] The mainstream augmented reality optical display solution causes the vergence accommodation conflict of the human eye. The retinal projection display can solve the vergence accommodation conflict, but its eye movement range is small, and it does not provide a monocular depth cue.

[0005] Therefore, it is an urgent problem to be solved to realize image display, especially three-dimensional image display, on a monocular eye. SUMMARY

[0006] The purpose of the present application is to provide a near-eye display method and system based on retinal projection, which superimposes a two-dimensional image on a spherical wave light beam, then diffracts the spherical image light beam with a non-periodic fringe to change the divergence angle of the spherical image light beam, transmits the light beam through total reflection in a waveguide, emits the light beam from a coupling-out element with a non-periodic fringe, converts the divergent spherical light into convergent spherical light, converges at the retinal point, generates multiple retinal points corresponding to the two-dimensional images from multiple viewpoints of the same three-dimensional scene, and generates a three-dimensional virtual image from the two-dimensional images on the multiple retinal points, thereby realizing the observation of a three-dimensional scene on a monocular eye and eliminating the vergence accommodation conflict.

[0007] In a first aspect, the above-mentioned purpose of the present application is achieved by the following technical solution:

[0008] A near-eye display method based on retinal projection, comprising: generating a first spherical image wave based on a two-dimensional image; performing divergence angle conversion on the first spherical image wave; converting the first spherical image wave with a first divergence angle into a second spherical image wave with a second divergence angle; and converting the second spherical image wave into a third spherical image wave with a third divergence angle, wherein the first spherical image wave and the second spherical image wave are divergent waves, and the third spherical image wave is a convergent wave, and the third spherical image wave converges at a retinal point, and a two-dimensional image can be observed at the retinal point.

[0009] The application is further configured to convert the first spherical image wave into the second spherical image wave by using a first non-periodic interference fringe, and convert the second spherical image wave into the third spherical image wave by using a second non-periodic interference fringe.

[0010] The application is further configured to interfere the first spherical wave with the second spherical wave to generate a first holographic interference image, intercept an image including N fringes from the first holographic interference image as the first non-periodic interference fringe, totally reflect the second spherical wave to obtain a third spherical wave, interfere the third spherical wave with a fourth spherical wave to generate a second holographic interference image, and intercept an image including N fringes from the second holographic interference image as the second non-periodic interference fringe, wherein the first spherical wave and the second spherical wave are both divergent spherical waves, and the fourth spherical wave is a convergent spherical wave.

[0011] The application is further configured to totally reflect and transmit the second spherical image wave in a waveguide, and the angle between each light ray and the normal line of the waveguide incident surface must be greater than the critical angle of total reflection when the second spherical image wave enters the waveguide, and the angles between the two most edge light rays are a first angle d and a second angle e, respectively, as shown in the following formula:

[0012]

[0013] wherein m is the number of times of total reflection of the light ray in the waveguide, L is the thickness of the waveguide, A is the incident point of the most edge first light ray at the first non-periodic interference fringe, B is the incident point of the most edge second light ray at the first non-periodic interference fringe, C is the exit point of the most edge first light ray at the second non-periodic interference fringe, and D is the exit point of the most edge second light ray at the second non-periodic interference fringe.

[0014] The divergence angle b of the second spherical image wave is shown in the following formula:

[0015]

[0016] The application is further configured to include at least two two-dimensional images from different viewpoints of the same three-dimensional scene, the first spherical wave is a divergent wave, at least two sub-spherical waves are generated, each two-dimensional image is superimposed on a sub-spherical wave, a plurality of spherical sub-image waves are generated, each spherical sub-image wave is expanded along a one-dimensional direction, and each spherical sub-image wave generates a convergent spherical sub-image wave after two times of divergence angle conversion, converges at a view point, and at least two view points enter the human eye at the same time, forming a three-dimensional virtual image on a monocular.

[0017] The application is further configured to interfere the first spherical wave with different second divergent spherical waves to generate different first interference fringe images, cut sub-images including a certain number of fringes from each first interference fringe image as a coupling-in image for the first time of divergence angle conversion of each spherical sub-image wave, respectively perform total reflection on each second divergent spherical wave to obtain different third spherical waves, and interfere each third spherical wave with a fourth convergent spherical wave to generate a second interference fringe image, and cut sub-images including a certain number of fringes from each second interference fringe image as a coupling-out image for the second time of divergence angle conversion of each spherical sub-image wave.

[0018] The application is further configured to arrange all the coupling-in images in one dimension, and each coupling-in image is independent of each other, arrange all the coupling-out images in one dimension, and each coupling-out image overlaps at an adjacent position, and the overlapping part is used for simultaneously performing divergence angle conversion on adjacent spherical sub-image waves.

[0019] The application is further configured to, when the distance between two adjacent view points is less than or equal to a set value, at least two view points fall into a single pupil at the same time, and the view points not falling into the pupil are used to expand the eyebox.

[0020] In the second aspect, the above application purpose of the application is achieved by the following technical scheme.

[0021] A near-eye display system based on retinal projection includes an image projector and a light processing system; the image projector is used for superimposing a two-dimensional image light beam on a first spherical wave with a first divergence angle to form an image spherical light wave; and the light processing system is used for diffracting the image spherical light wave to convert it into a third spherical image light wave with a third divergence angle, wherein the third spherical image light wave is a convergent wave, and the third spherical image wave converges at a view point, and the two-dimensional image can be observed at the view point.

[0022] The application is further configured that the image projector comprises a laser image module and a two-dimensional or one-dimensional scanning galvanometer, the laser image module is used to generate at least two modulated light beams comprising two-dimensional image information according to two-dimensional images of at least two viewpoints of the same three-dimensional scene, and the two-dimensional or one-dimensional scanning galvanometer is used to convert the modulated light beams into spherical light beams; the light processing system comprises a total reflection waveguide, at least one in-coupling element and at least one out-coupling element, each in-coupling element is distributed on the surface of the waveguide in a one-dimensional manner and is independent of each other, and each out-coupling element is distributed on the surface of the waveguide in a one-dimensional manner, and adjacent two out-coupling elements overlap with each other.

[0023] Compared with the prior art, the application has the beneficial technical effects that:

[0024] 1. The application diffracts the divergent spherical light into the waveguide through the in-coupling element with non-periodic stripes, converges the divergent spherical light through the out-coupling element with non-periodic stripes, and realizes the convergence of the image of the eye point;

[0025] 2. Further, the application enables the three-dimensional image to be observed by one eye by overlapping the multiple out-coupling elements to enable at least two eye points to enter the pupil of the human eye;

[0026] 3. Further, the application changes the divergence angle of the light beam by adopting the non-periodic stripes to convert the divergent spherical light into convergent spherical light, and realizes the observation of the three-dimensional image by one eye;

[0027] 4. Further, the application forms multiple eye points, at least two of which converge on a single pupil to form a three-dimensional image, and the eye points not falling into the single pupil expand the eye box. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a two-dimensional image display light path schematic diagram of one specific embodiment of the application;

[0029] Figure 2 is a three-dimensional image display light path schematic diagram of one specific embodiment of the application;

[0030] Figure 3 is a three-dimensional image display light path schematic diagram of one specific embodiment of the application;

[0031] Figure 4 is a three-dimensional image display light path schematic diagram of one specific embodiment of the application;

[0032] Figure 5 is a three-dimensional image display light path schematic diagram of one specific embodiment of the application;

[0033] Figure 6 is an enlarged view of the coupling-out element of one embodiment of the present application;

[0034] Figure 7 is a schematic diagram of a three-dimensional virtual image path of one embodiment of the present application;

[0035] Figure 8 is a schematic diagram of a spherical wave generation of one embodiment of the present application;

[0036] Figure 9 is a schematic diagram of a coupling-in element stripe of one embodiment of the present application;

[0037] Figure 10 is a schematic diagram of a coupling-out element stripe of one embodiment of the present application. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the attached drawings.

[0039] A near-eye display method based on retinal projection of the present application.

[0040] Near-eye display of a two-dimensional image:

[0041] The two-dimensional image is coupled after being superimposed on a spherical wave and converges at a retinal point, and the two-dimensional image can be observed from the retinal point.

[0042] The two-dimensional image is superimposed on a first spherical wave to obtain a first spherical image signal, the divergence angle of the first spherical wave is a, the first spherical image signal is a light beam with a divergence angle of a, the first spherical image is shot into a coupling-in element provided with a first aperiodic stripe, a second spherical image signal with a second divergence angle b is obtained, the second spherical image signal is transmitted in the waveguide by total reflection, and the second spherical image signal is shot out from the coupling-in element provided with a second aperiodic stripe to become a third spherical image signal with a convergence angle c. The third spherical image signal converges at a retinal point, and the two-dimensional image can be observed from the retinal point.

[0043] The first spherical wave and the second spherical wave interfere to generate a first holographic interference stripe, an image including K stripes is intercepted from the first holographic interference stripe as the first aperiodic stripe, and the first spherical wave and the second spherical wave are both divergent spherical waves.

[0044] The second spherical wave is totally reflected to obtain a third spherical wave, the third spherical wave and a fourth spherical wave interfere to generate a second holographic interference stripe, an image including K stripes is intercepted from the second holographic interference stripe as the second aperiodic stripe, and the fourth spherical wave is a convergent spherical wave.

[0045] As shown in FIG. 1, a two-dimensional image is superimposed on a first spherical wave to obtain a first spherical image signal, the divergence angle of the first spherical wave is a, the first spherical image signal is a light beam with a divergence angle of a, the first spherical image is shot into a coupling-in element provided with a first aperiodic stripe, a second spherical image signal with a second divergence angle b is obtained, the second spherical image signal is transmitted in the waveguide by total reflection, and the second spherical image signal is shot out from the coupling-in element provided with a second aperiodic stripe to become a third spherical image signal with a convergence angle c. The third spherical image signal converges at a retinal point, and the two-dimensional image can be observed from the retinal point. Figure 1As shown, the two marginal rays of the second spherical image signal 501 are marked as 5011 and 5012 respectively, the angle between ray 5011 and the normal of the waveguide incident surface is d, the angle between ray 5012 and the normal of the waveguide incident surface is e, and the second spherical image signal 501 propagates in the waveguide by total reflection, so the incident angle of each ray in the second spherical image signal 501 should be greater than the critical angle of total reflection. As shown in the figure,

[0046]

[0047]

[0048] where m is the number of times of total reflection of the ray in the waveguide, L is the thickness of the waveguide, A is the incident point of ray 5011 on the coupling-in element 401, B is the incident point of ray 5012 on the coupling-in element 401, C is the exit point of ray 5011 on the coupling-out element 601, and D is the exit point of ray 5012 on the coupling-out element 601.

[0049] Here, both angles d and e should be greater than the critical angle of total reflection.

[0050] The angle b between ray 5011 and ray 5012 is e-d, i.e. the divergence angle b of the light beam 501:

[0051]

[0052] Properly setting the positions of the coupling-in element and the coupling-out element enables the observation of a two-dimensional image at the view point.

[0053] Near-eye display of a three-dimensional image, comprising:

[0054] Obtaining a three-dimensional image, selecting at least two view points, and taking a photograph of a three-dimensional scene at each view point to obtain at least two two-dimensional images, which are used to fuse the two-dimensional images of different view points to obtain a three-dimensional image of the three-dimensional scene.

[0055] Coupling the two-dimensional images of each view point to a spherical wave after superposition, converging on the corresponding view point of each view point, and reversely extending the rays of all view point images to form a three-dimensional virtual image at a certain position in front of the view point. When at least two view points enter the pupil of the human eye, the human eye can observe a three-dimensional scene.

[0056] The two-dimensional image of the ith view point is superimposed on the ith spherical sub-wave of the 5th spherical wave, and the divergence angle of the ith spherical sub-wave is ai, to obtain the 20th ith spherical sub-image signal. After the 20th ith spherical sub-image signal is injected into the 40th ith coupling-in element, it is diffracted into the 50th ith divergent spherical light with a divergence angle of bi, which is transmitted by total reflection in the waveguide, and at the 60th ith coupling-out element, the divergent spherical light with a divergence angle of bi is diffracted into the 70th ith convergent spherical light beam with a convergence angle of ci, which converges at the 80th ith view point. The value of i corresponds to the number of view points.

[0057] The 3rd ith non-periodic holographic image is generated by interference of the 5th spherical wave and the 6th ith spherical wave, both of which are divergent waves. A sub-image including Q interference fringes is cut from the 3rd ith non-periodic holographic image as the holographic fringe of the 40th ith coupling-in element.

[0058] The 7th ith spherical wave is generated by total reflection of the 6th ith spherical wave, and the 4th ith non-periodic holographic image is formed by interference of the 7th ith spherical wave and the 8th ith spherical wave, which is a convergent wave. A sub-image including Q interference fringes is cut from the 4th ith non-periodic holographic image as the holographic fringe of the 60th ith coupling-out element.

[0059] For different view points i, different i corresponds to different 6th ith spherical waves and different 8th ith spherical waves.

[0060] The two edges of the 50th ith divergent spherical light beam are marked as 50i1 and 50i2, respectively. When the 50i1 light enters the waveguide, the angle between the 50i1 light and the normal of the waveguide surface is di1, which is marked as the incident angle di1. When the 30i2 light enters the waveguide, the angle between the 30i2 light and the normal of the waveguide surface is ei1, which is marked as the incident angle ei1. The calculation method of the incident angle is as follows:

[0061]

[0062] Where m is the number of total reflections of the light in the waveguide, L is the thickness of the waveguide. Ai is the incident point of the light 50i1 on the coupling-in element 40i, Bi is the incident point of the light 50i2 on the coupling-in element 40i, Ci is the exit point of the light 50i1 on the coupling-out element 60i, and Di is the exit point of the light 50i2 on the coupling-out element 60i.

[0063] Here, the angles di1 and ei1 are both greater than the critical angle of total reflection. The angle between the light 50i1 and the light 50i2 is bi1 = ei1 - di1, that is, the divergence angle bi1 of the light beam 50i, which is calculated by the following formula:

[0064]

[0065] The 40i coupling-in element diffracts the spherical light beam 20i with divergence angle ai into a spherical light beam 50i with divergence angle bi, and the coupling-out optical element 60i diffracts the spherical light beam 50i with divergence angle bi into a spherical light beam 70i with convergence angle ci.

[0066] When the i values are different, the 40i coupling-in elements corresponding to the i values are independently arranged on the waveguide surface.

[0067] At each 80i view point, the human eye can observe the image signal carried by the convergent light beam. The distance between the view points is controlled to be less than or equal to a set value, so that at least two view points enter the monocular pupil range. The light rays on all the view points are reversely extended and converge into a three-dimensional image at a certain distance in front of the monocular pupil, so that the monocular pupil can see a true three-dimensional image, and the vergence accommodation conflict is eliminated. The view points that do not enter the monocular pupil are used to expand the eye box, and the movement of the human eye will not affect the viewing of the image.

[0068] In order to make all the view points enter the monocular pupil range, two adjacent coupling-out elements are arranged to overlap at the edge portion. The angle of incidence of the 50i light beam on the overlapping portion 600i is different from the angle of incidence of the 50(i+1) light beam on the overlapping portion 600i. By using the angle selectivity of the holographic optical element, the coupling-out element of the overlapping portion 600i diffracts the 50i light beam into the 70i light beam and also diffracts the 50(i+1) light beam into the 70(i+1) light beam.

[0069] In this application, three view points are described. For multiple view points, the same principle applies and will not be described again.

[0070] As shown in FIG. 1, Figure 2 The image projector 10 superimposes the two-dimensional images of each view point on the fifth spherical wave with different emission angles to generate spherical image light beams with different divergence angles, which are marked as 201, 202 and 203 respectively. In order to clearly describe the paths of the light beams, the spherical image light beams are split into Figure 2 , Figure 3 , Figure 4 , Figure 5 and are described respectively.

[0071] The image projector 10 projects the spherical image light beam 201 onto the coupling-in element 401. After the diffraction of the coupling-in element 401, the spherical image light beam 501 is generated in the waveguide 30. The spherical image light beam 501 is transmitted by total reflection in the waveguide and is emitted from the coupling-out element 601 to form a convergent light beam 701 that converges at the view point 801.

[0072] The 5th spherical wave and the 61st spherical wave interfere to generate the 31st aperiodic holographic image, both the 5th spherical wave and the 61st spherical wave are divergent waves, a sub-image including Q interference fringes is intercepted from the 31st aperiodic holographic image as the holographic fringes of the 401st in-coupling element.

[0073] The 61st spherical wave is totally reflected to generate the 71st spherical wave, the 71st spherical wave and the 81st spherical wave interfere to form the 41st aperiodic holographic image, the 81st spherical wave is a convergent wave, a sub-image including Q interference fringes is intercepted from the 41st aperiodic holographic image as the holographic fringes of the 601st out-coupling element.

[0074] Similarly, the image projector 10 projects the spherical image beam 202 onto the in-coupling element 402, after diffraction of the in-coupling element 402, the spherical image beam 202 enters the waveguide 30 to generate the spherical image beam 502, the spherical image beam 502 is totally reflected in the waveguide and exits from the out-coupling element 602 to form the convergent beam 702 converging at the eyebox 802.

[0075] The 5th spherical wave and the 62nd spherical wave interfere to generate the 32nd aperiodic holographic image, both the 5th spherical wave and the 62nd spherical wave are divergent waves, a sub-image including W interference fringes is intercepted from the 32nd aperiodic holographic image as the holographic fringes of the 402nd in-coupling element.

[0076] The 62nd spherical wave is totally reflected to generate the 72nd spherical wave, the 72nd spherical wave and the 82nd spherical wave interfere to form the 42nd aperiodic holographic image, the 82nd spherical wave is a convergent wave, a sub-image including W interference fringes is intercepted from the 42nd aperiodic holographic image as the holographic fringes of the 602nd out-coupling element.

[0077] The image projector 10 projects the spherical image beam 203 onto the in-coupling element 403, after diffraction of the in-coupling element 403, the spherical image beam 203 enters the waveguide 30 to generate the spherical image beam 503, the spherical image beam 503 is totally reflected in the waveguide and exits from the out-coupling element 603 to form the convergent beam 703 converging at the eyebox 803.

[0078] The 5th spherical wave and the 63rd spherical wave interfere to generate the 33rd aperiodic holographic image, both the 5th spherical wave and the 63rd spherical wave are divergent waves, a sub-image including R interference fringes is intercepted from the 33rd aperiodic holographic image as the holographic fringes of the 403rd in-coupling element.

[0079] The 63th spherical wave is totally reflected to generate the 73th spherical wave, the 73th spherical wave interferes with the 83th spherical wave to form the 43th non-periodic holographic image, the 83th spherical wave is a convergent wave, a sub-image including R interference fringes is cut from the 43th non-periodic holographic image to be a holographic fringe of the 603th coupling-out element.

[0080] The spherical waves 61, 62, 63 are mutually different spherical waves, and the spherical waves 81, 82, 83 are mutually different spherical waves.

[0081] The coupling-in elements 401, 402, 403 are independently arranged in one dimension, and two adjacent coupling-out elements are partially overlapped at the edge, as shown in the figure. Figure 6 As shown in the figure, the overlapped part of the coupling-out elements 601, 602 is a coupling-out optical element 6001, and the overlapped part of the coupling-out elements 602, 603 is a coupling-out optical element 6002.

[0082] The coupling-out element 601 diffracts the light beam 501 into a convergent light beam 701, the coupling-out element 602 diffracts the light beam 502 into a convergent light beam 702, and the coupling-out element 603 diffracts the light beam 503 into a convergent light beam 703. The coupling-out element 601 and the coupling-out element 602 have an overlapped area, which is a coupling-out optical element 6001, and the coupling-out element 602 and the coupling-out element 603 have an overlapped area, which is a coupling-out optical element 6002. In the coupling-out optical element 6001 in the overlapped area, there are interference fringes capable of being used for coupling-out the light beam 501 and interference fringes capable of being used for coupling-out the light beam 502. In the coupling-out optical element 6002 in the overlapped area, there are interference fringes capable of being used for coupling-out the light beam 502 and interference fringes capable of being used for coupling-out the light beam 503.

[0083] The angle at which the light beam 501 is incident on the coupling-out optical element 6001 is different from the angle at which the light beam 502 is incident on the coupling-out optical element 6001, and the coupling-out optical element 6001 diffracts the light beam 501 into the convergent light beam 701 and diffracts the light beam 502 into the convergent light beam 702 by using the angle selectivity of the holographic optical element. The angle at which the light beam 502 is incident on the coupling-out optical element 6002 is different from the angle at which the light beam 503 is incident on the coupling-out optical element 6002, and the coupling-out optical element 6002 diffracts the light beam 502 into the convergent light beam 702 and diffracts the light beam 503 into the convergent light beam 703 by using the angle selectivity of the holographic optical element.

[0084] When the distance between two adjacent view points is less than a set value, at least two view points enter the range of the monocular pupil at the same time, and the human eye sees a true three-dimensional image, and the vergence accommodation conflict is eliminated.

[0085] In a specific embodiment of the present application, the set value is 3 mm.

[0086] As shown in the figure, the coupling-out element 601 diffracts the light beam 501 into a convergent light beam 701, the coupling-out element 602 diffracts the light beam 502 into a convergent light beam 702, and the coupling-out element 603 diffracts the light beam 503 into a convergent light beam 703.Figure 7 As shown, the light rays of each eye point are reversely extended to form a three-dimensional virtual image 120 at a certain position in front of the pupil, and the line connecting each image point 1201, 1202, 1203 on the three-dimensional virtual image 120 and the eye point 801 intersects with the coupling-out element 60, i.e. the pixel point of the light beam 1301. The light beam 1301 carries the two-dimensional image information of the three-dimensional image 120 observed by the eye point 801.

[0087] Similarly, the light beam 1302 carries the two-dimensional image information of the three-dimensional image 120 observed by the eye point 802, and the light beam 1303 carries the two-dimensional image information of the three-dimensional image 120 observed by the eye point 803.

[0088] In one specific embodiment of the present application, as shown in Figure 8 The laser image module 101 outputs a fine light beam 102, which is modulated by red, green and blue lasers and includes two-dimensional image information. The two-dimensional scanning galvanometer 103 can rotate in two directions, and only one direction of rotation is shown in the figure. The fine light beam 102 is reflected by the two-dimensional scanning galvanometer to form a divergent spherical light beam 104.

[0089] The two-dimensional scanning galvanometer can be realized by two one-dimensional scanning galvanometers.

[0090] In one specific embodiment of the present application, the image of the coupling-in element is as shown in Figure 9 The incident spherical light 201 is diffracted by the interference fringes on the coupling-in element 401 to generate a spherical light 501.

[0091] In one specific embodiment of the present application, the image of the coupling-out element is as shown in Figure 10 The spherical light 501 is diffracted by the interference fringes on the coupling-out element 601 to generate a spherical light 701.

[0092] A near-eye display system based on retinal projection according to the present application comprises an image projector and a light processing system. The image projector is used to superimpose a two-dimensional image on a first divergent spherical wave with a first divergence angle to form an image spherical light wave. The light processing system is used to convert the image spherical light wave into a third spherical image wave with a third divergence angle after diffraction. The third spherical image wave is convergent light, which is further converged on an eye point. From the eye point, the two-dimensional image signal carried by the convergent light beam can be observed.

[0093] The light processing system comprises a total reflection waveguide, at least one coupling-in element and at least one coupling-out element. The coupling-in elements are distributed in a one-dimensional manner on the surface of the waveguide and are independent of each other. The coupling-out elements are distributed in a one-dimensional manner on the surface of the waveguide, and adjacent two coupling-out elements overlap with each other. The coupling-in elements and the coupling-out elements are distributed on the same surface of the waveguide, and are tightly attached to the surface of the waveguide without gaps.

[0094] For the same three-dimensional scene, N two-dimensional images are obtained by shooting from N viewpoints, each two-dimensional image is superimposed on a spherical wave, and N image spherical light waves with different divergence angles are generated correspondingly. After passing through the light processing system, N view points are generated. The N view points are simultaneously dropped into the pupil range of the human eye. The light rays on each view point are reversely extended to form a three-dimensional virtual image at a certain position in front of the human eye. The human eye observes the three-dimensional scene.

[0095] Correspondingly, the light processing system includes N coupling-in elements, a waveguide, and N coupling-out elements. Each coupling-in element and each coupling-out element are arranged on the same surface of the waveguide and have no gap between them.

[0096] Each coupling-in element is arranged in a one-dimensional manner, and each coupling-in element is independent of each other. Each coupling-out element is also arranged in a one-dimensional manner, and adjacent coupling-out elements partially overlap. The overlapping area is used to diffract adjacent light beams simultaneously.

[0097] The above are preferred embodiments of the present application, which do not limit the protection scope of the present application. Therefore, any equivalent changes made in accordance with the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A near-eye display method based on retinal projection, characterized by: The method comprises the following steps: generating a first spherical image wave based on a two-dimensional image; performing a divergence angle conversion on the first spherical image wave; converting the first spherical image wave with a first divergence angle into a second spherical image wave with a second divergence angle; and converting the second spherical image wave into a third spherical image wave with a third divergence angle, wherein the first spherical image wave and the second spherical image wave are divergent waves, the third spherical image wave is a convergent wave, and the third spherical image wave converges at a single view point, and the two-dimensional image can be observed at the view point. The first spherical image wave is converted into the second spherical image wave by using a first non-periodic interference fringe, and the second spherical image wave is converted into the third spherical image wave by using a second non-periodic interference fringe. The first spherical wave and the second spherical wave interfere to generate a first holographic interference image, an image including N fringes is cut from the first holographic interference image as a first non-periodic interference fringe, the second spherical wave is totally reflected to obtain a third spherical wave, the third spherical wave and a fourth spherical wave interfere to generate a second holographic interference image, an image including N fringes is cut from the second holographic interference image as a second non-periodic interference fringe, wherein the first spherical wave and the second spherical wave are both divergent spherical waves, and the fourth spherical wave is a convergent spherical wave.

2. The near-eye display method based on retinal projection of claim 1, wherein: The second spherical image wave is totally reflected and transmitted in a waveguide, when the second spherical image wave enters the waveguide, the included angle between each light ray and the normal line of the waveguide incidence plane must be greater than the critical angle of total reflection, the included angles of the two light rays at the edge are a first included angle d and a second included angle e, respectively as follows: Wherein, m is the number of times of total reflection of the light ray in the waveguide, L is the thickness of the waveguide; A is the incidence point of the first light ray at the edge in the first non-periodic interference fringe, B is the incidence point of the second light ray at the edge in the first non-periodic interference fringe, C is the emission point of the first light ray at the edge in the second non-periodic interference fringe, and D is the emission point of the second light ray at the edge in the second non-periodic interference fringe; The divergence angle b of the second spherical image wave is as follows:

3. The retinal projection based near-eye display method of claim 1, wherein: The method comprises the following steps: including at least two two-dimensional images from different view points of the same three-dimensional scene, the first spherical wave is a divergent wave, at least two sub-spherical waves are generated, each two-dimensional image is superimposed on a sub-spherical wave, a plurality of spherical sub-image waves are generated, each spherical sub-image wave is unfolded along a one-dimensional direction, and each spherical sub-image wave converges at a view point after two divergence angle conversions, at least two view points enter the human eye at the same time, and a three-dimensional virtual image is formed on the monocular eye.

4. The near-eye display method based on retinal projection of claim 3, wherein: The first spherical wave and different second divergent spherical waves interfere to generate different first interference fringe images, a sub-image including a certain number of fringes is cut from each first interference fringe image as a coupling-in image for the first divergence angle conversion of each spherical sub-image wave, each second divergent spherical wave is totally reflected to obtain a different third spherical wave, each third spherical wave interferes with a fourth convergent spherical wave to generate a second interference fringe image, a sub-image including a certain number of fringes is cut from each second interference fringe image as a coupling-out image for the second divergence angle conversion of each spherical sub-image wave.

5. A near-eye display method based on retinal projection according to claim 4, characterized in that: All the in-coupled images are arranged in one dimension and are independent of each other, all the out-coupled images are arranged in one dimension and overlap at adjacent positions, and the overlapping part is used for simultaneously performing the divergence angle conversion on the adjacent spherical sub-image waves.

6. A near-eye display method based on retinal projection according to claim 4, characterized in that: When the distance between two adjacent view points is less than or equal to a set value, at least two view points fall into a single pupil at the same time, and the view points not falling into the pupil are used to expand the eye box.

7. A near-eye display system based on retinal projection for performing the method of any one of claims 1 to 6. The image projector is used for superimposing a two-dimensional image light beam on a first spherical wave with a first divergence angle to form an image spherical light wave; and the light processing system is used for diffracting the image spherical light wave to convert it into a third spherical image light wave with a third divergence angle, wherein the third spherical image light wave is a converging wave, and the third spherical image wave converges at a view point, and the two-dimensional image can be observed at the view point.

8. The near-eye, retinal projection-based display system of claim 7, wherein: The image projector includes a laser image module and a two-dimensional or one-dimensional scanning galvanometer, the laser image module is used for generating at least two modulated light beams including two-dimensional image information according to two-dimensional images of at least two view points of the same three-dimensional scene, and the two-dimensional or one-dimensional scanning galvanometer is used for converting the modulated light beams into spherical light beams; and the light processing system includes a total reflection waveguide, at least one in-coupling element and at least one out-coupling element, each in-coupling element is arranged in one dimension on the surface of the waveguide and is independent of each other, each out-coupling element is arranged in one dimension on the surface of the waveguide, and adjacent two out-coupling elements overlap with each other, and each in-coupling element and each out-coupling element are arranged on the same surface of the waveguide.

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