CN114647082A - Pupil expanding device, binocular display method and image display method - Google Patents

Abstract

The invention discloses a pupil expanding device, a binocular display method and an image display method, wherein the pupil expanding device comprises at least one layer of optical waveguide plate, a first entrance pupil unit, a second entrance pupil unit and an exit pupil unit are arranged on the optical waveguide plate, and the first entrance pupil unit and the second entrance pupil unit are symmetrically distributed on two sides of the exit pupil unit; the first entrance pupil unit is used for diffracting first input light incident at a first angle into first transmission light, the second entrance pupil unit is used for diffracting second input light incident at a second angle into second transmission light, and the exit pupil unit is used for diffracting the first transmission light and the second transmission light into output light. The binocular display device disclosed by the invention nearly doubles the angular width of a virtual image which can be presented by the existing optical waveguide technology, realizes simultaneous binocular imaging through single-layer waveguide integration, greatly improves the immersion experience of a user, and simultaneously considers key parameters such as cost, weight, volume and the like.

Description

Pupil expanding device, binocular display method and image display method

Technical Field

The invention relates to the technical field of virtual display, in particular to a pupil expanding device, a binocular display method and an image display method.

Background

In the prior art, multiple projectors and multiple layers of waveguides are usually used to realize large-angle virtual image display, that is, multiple projectors are paired with multiple waveguides one by one, each pair of projector and waveguide realizes virtual image presentation in a partial angle range, and partial images presented by each pair of projector and waveguide are spliced to realize a virtual image in a large angle range. The scheme adopts multilayer waveguides, so that the overall weight of the waveguides is increased, and the cost is doubled. Meanwhile, the scheme is monocular imaging, so that the number of the light engines is doubled when binocular imaging is performed, and the plurality of light engines are not favorable for wearing comfort and have the defects of high cost, high power consumption and the like.

Therefore, in the current technology, the existing pupil expanding device is limited by the refractive index of the material of the optical waveguide plate, and the angle broadening of the virtual image which can be realized by the pupil expanding device is small, which is not enough to satisfy the immersive display experience.

Disclosure of Invention

The embodiment of the invention provides a pupil expanding device, a binocular display method and an image display method, and aims to realize large-angle broadened virtual image display so as to improve the immersion experience of a user and simultaneously give consideration to key parameters such as cost, weight, volume and the like of the display device.

In a first aspect, an embodiment of the present invention provides a pupil expanding device, including at least one optical waveguide plate, where the optical waveguide plate is provided with a first entrance pupil unit, a second entrance pupil unit, and an exit pupil unit, and the first entrance pupil unit and the second entrance pupil unit are symmetrically distributed on two sides of the exit pupil unit; the first entrance pupil unit is used for diffracting first input light incident at a first angle into first transmission light, the second entrance pupil unit is used for diffracting second input light incident at a second angle into second transmission light, and the exit pupil unit is used for diffracting the first transmission light and the second transmission light into output light.

In a second aspect, an embodiment of the present invention provides a binocular display device, including the pupil expanding device according to the first aspect, and a light engine module, where the light engine module includes a first light engine and a second light engine;

the first light engine provides light to the first entrance pupil unit along a direction making a third angle with a normal vector to the light exit surface of the light guide plate; the second light engine provides light to the second entrance pupil unit along a direction forming a fourth angle with a normal vector of the light-emitting surface of the light guide plate.

In a third aspect, a binocular displaying method according to an embodiment of the present invention is implemented by using the binocular displaying apparatus according to the second aspect.

In a fourth aspect, an image display method according to an embodiment of the present invention is implemented by using the binocular display apparatus according to the second aspect.

The embodiment of the invention provides a pupil expanding device, a binocular display method and an image display method, wherein the pupil expanding device comprises at least one layer of optical waveguide plate, a first entrance pupil unit, a second entrance pupil unit and an exit pupil unit are arranged on the optical waveguide plate, and the first entrance pupil unit and the second entrance pupil unit are symmetrically distributed on two sides of the exit pupil unit; the first entrance pupil unit is used for diffracting first input light incident at a first angle into first transmission light, the second entrance pupil unit is used for diffracting second input light incident at a second angle into second transmission light, and the exit pupil unit is used for diffracting the first transmission light and the second transmission light into output light. The embodiment of the invention divides a virtual image with large angle broadening into two virtual images with small angle broadening in half, the two virtual images with small angle broadening are projected and output through two light engines respectively, two entrance pupil units constructed on a single-layer light guide plate are coupled into a light guide plate respectively, and the two virtual images with small angle broadening are coupled out by the same exit pupil unit after passing through an expanding pupil in the light guide plate, spliced and fused into an initial virtual image with large angle broadening, and are received by two eyes for imaging. The binocular display device disclosed by the embodiment of the invention almost doubles the angular width of the virtual image which can be presented by the existing optical waveguide technology, realizes binocular simultaneous imaging through single-layer waveguide integration, greatly improves the immersion experience of a user, and simultaneously considers key parameters such as cost, weight, volume and the like.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

Figure 1 is a first structural schematic diagram of a pupil expanding device according to an embodiment of the present invention;

figure 2 is an expanded view of a complete wide-angle stretched image by a pupil expansion device according to an embodiment of the present invention;

FIG. 3 is an expanded view of the image of the portion A in FIG. 2;

FIG. 4 is an expanded view of the B partial image of FIG. 2;

FIG. 5 is a schematic diagram showing a large angle spread image of FIG. 2;

figure 6 is a second schematic structural diagram of a pupil expansion device according to an embodiment of the present invention;

FIG. 7 is an expanded view of the image of the portion A of FIG. 6;

FIG. 8 is an expanded view of the B-portion image of FIG. 6;

FIG. 9 is a schematic diagram showing the wide angle stretched image of FIG. 6;

figure 10 is a first structural schematic diagram of another angle of a pupil expanding device according to an embodiment of the present invention;

figure 11 is a second structural diagram of another angle of a pupil expansion device according to an embodiment of the present invention;

figure 12 is a wave vector diagram of a pupil expanding device according to an embodiment of the present invention;

figure 13 is another wave vector diagram of a pupil expanding device according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to any and all possible combinations of one or more of the associated listed items and includes such combinations.

Referring to fig. 1, an embodiment of the present invention provides a pupil expanding device EPE1, which includes at least one layer of optical waveguide plate SUB1, where a first entrance pupil unit DOE1a, a second entrance pupil unit DOE1b, and an exit pupil unit DOE3 are disposed on the optical waveguide plate SUB1, and the first entrance pupil unit DOE1a and the second entrance pupil unit DOE1b are symmetrically distributed on two sides of the exit pupil unit DOE 3; the first entrance pupil unit DOE1a is configured to diffract first input light incident at a first angle into first transmission light B1a, the second entrance pupil unit DOE1B is configured to diffract second input light incident at a second angle into second transmission light B1B, and the exit pupil unit DOE3 is configured to diffract the first transmission light B1a and the second transmission light B1B into output light.

The pupil expanding device EPE1 according to this embodiment includes at least one layer of optical waveguide plate SUB1, including at least one layer of optical waveguide plate SUB1, two entrance pupil units (i.e., a first entrance pupil unit DOE1a, a second entrance pupil unit DOE1b) are symmetrically constructed on the optical waveguide plate SUB1, the first entrance pupil unit DOE1a and the second entrance pupil unit DOE1b are each used for coupling an image output by the ENG1 (i.e., a first light engine for projecting an image) and the ENG2 (i.e., a second light engine for projecting an image) into the optical waveguide plate SUB1, respectively, and expanding the image in an approximately first direction (e.g., SY axis direction), the first entrance pupil unit DOE1a and the second entrance pupil unit DOE1b are symmetrically distributed on both sides of a region of the common exit pupil unit DOE3, the exit pupil unit DOE3 realizes that an image display region expands the image in a second direction (e.g., SX axis direction) approximately perpendicular to the first direction, and couples the two light rays out of the optical waveguide plate SUB1 to realize the light splicing of the two projected images, and further, the final large-angle expanded image display is realized.

The pupil expanding device EPE1 described in this embodiment has the function of implementing image stitching and binocular imaging by using a single-layer optical waveguide plate SUB1, and takes the wearing comfort and the production cost into consideration while implementing wide-angle image widening imaging.

In an embodiment, the exit pupil element DOE3 is a one-dimensional grating, and the one-dimensional grating is used for realizing image expansion and image coupling output in a corresponding direction, and the one-dimensional grating direction is ± 10 ° from the SY axis direction.

Further, as shown in fig. 1, a first pupil expanding unit DOE2a and a second pupil expanding unit DOE2b are further disposed on the optical waveguide SUB1, the first pupil expanding unit DOE2a and the second pupil expanding unit DOE2b are symmetrically distributed on two sides of the exit pupil unit DOE3, the first pupil expanding unit DOE2a is located below the first entrance pupil unit DOE1a, and the second pupil expanding unit DOE2b is located below the second entrance pupil unit DOE1 b;

the first pupil expanding unit DOE2a is configured to diffract the first light guiding light B1a into third light guiding light B2a, and the second pupil expanding unit DOE2B is configured to diffract the second light guiding light B1B into fourth light guiding light B2B.

In this embodiment, when the exit pupil unit DOE3 is a one-dimensional grating, the pupil expanding device EPE1 further includes two pupil expanding units corresponding to the two entrance pupil units (i.e. the first pupil expanding unit DOE2a and the second pupil expanding unit DOE2B), the first pupil expanding unit DOE2a and the second pupil expanding unit DOE2B respectively receive the light beams coupled into the optical waveguide plate SUB1 by the two entrance pupil units, i.e. the first pupil expanding unit DOE2a is used to diffract the first transmitted light B1a into the third transmitted light B2a, the second pupil expanding unit 632B is used to diffract the second transmitted light B1B into the fourth transmitted light B2B and to perform the first direction expansion on the light beams and change the propagation direction, the exit pupil unit DOE3 receives the image light beams processed by the first pupil expanding unit DOE a and the second pupil expanding unit DOE B and performs the first direction expansion on the light beams, and outputs the light beams 92 in the same time, is observed by human eyes. In a specific embodiment, the first angle and the second angle are different, and the first angle and the second angle are symmetrical with respect to a normal of the optical waveguide plate SUB 1.

As shown in fig. 2, a complete large-angle-spread image is divided into A, B two parts, A, B two parts of the image are loaded onto display panels DISP1 and DISP2 of the light engines ENG1 and ENG2, respectively, and projected and imaged by ENG1 and ENG2, respectively, to form output light beams OB0a and OB0b, respectively. The pupil expanding device EPE1 includes 2 entrance pupil units DOE1a and DOE1B, wherein the first entrance pupil unit DOE1a and the second entrance pupil unit DOE1B respectively receive the projected images of ENG1 (first light engine for projecting the projected image) and ENG2 (second light engine for projecting the projected image), and couple the image light into the light guide plate SUB1 to form the first light guide B1a and the second light guide B1B, and transmit in the light guide plate in a manner satisfying the total internal reflection condition. The first and second pupil expanding units DOE2a and DOE2B respectively corresponding to the first and second entrance pupil units DOE1a and DOE1B receive the first and second light transmission beams B1a and B1B, respectively, expand the light beams in the direction similar to the SY axis, change the propagation direction of the light beams, and form third and fourth light transmission beams B2a and B2B, respectively. The exit pupil unit DOE3 is located between the first pupil expanding unit DOE2a and the second pupil expanding unit DOE2B, and is configured to receive the third light transmission light B2a and the fourth light transmission light B2B, expand the light beam in an approximate SX axis direction, and couple the third light transmission light B2a and the fourth light transmission light B2B out of the light waveguide SUB1 to form free space transmission light OB3a and OB3B, where the transmission directions of OB3a and OB3B are the same as the light engine output lights OB0a and OB0B, respectively. Here, the exit pupil element DOE3 area covers the binocular viewing range of human eyes, and the output light beams OB3a and OB3b contain A, B two-part image information, and by controlling the position angles of the light engines ENG1 and ENG2 relative to the optical waveguide plate, aligned splicing of the output images can be achieved, thereby achieving the display of a complete large-angle-broadened image.

Fig. 3 and 4 show the light transmission when only a single light engine ENG1 or ENG2 is operated, respectively, and fig. 5 illustrates the light transmission of the image and the stitching of the final image to form a complete image in a top view.

In an embodiment, in connection with fig. 6, the exit pupil unit DOE3 is a two-dimensional grating formed by two crosswise arranged one-dimensional gratings, which provide two directional grating vectors, and the sum of the two directional grating vectors and the grating vector of the first or second entrance pupil unit DOE1a or DOE1b is 0.

In this embodiment, when the exit pupil unit DOE3 is a two-dimensional grating, the exit pupil unit DOE3 directly receives the light beams coupled into the optical waveguide plate SUB1 by the two entrance pupil unit regions, expands the light beams in two directions, and couples the light beams out of the optical waveguide plate to be observed by human eyes. The pupil expanding device EPE1 has the function of realizing image splicing and binocular imaging by adopting a single-layer waveguide plate, realizes wide-angle image widening and gives consideration to wearing comfort and production cost.

As shown in fig. 6, a complete large-angle-spread image is divided into A, B two parts, A, B two parts of the image are loaded onto display panels DISP1 and DISP2 of the light engines ENG1 and ENG2, respectively, and projected and imaged by ENG1 and ENG2, respectively, to form output light beams OB0a and OB0b, respectively. The pupil expanding device EPE1 comprises a first entrance pupil unit DOE1a and a second entrance pupil unit DOE1B, which first entrance pupil unit DOE1a and second entrance pupil unit DOE1B receive the projected images of ENG1 and ENG2, respectively, and couple the image light rays into the light guide plate SUB1, form a first light transmission B1a and a second light transmission B1B, and transmit in the light guide plate SUB1 in a manner that the total internal reflection condition is satisfied. The exit pupil unit DOE3 is located between said first and second entrance pupil units DOE1a and DOE1B for accepting first and second light guiding B1a and B1B. The exit pupil unit DOE3 is a two-dimensional grating formed by two one-dimensional gratings in a crossed arrangement, and can realize beam expansion of a light beam in two directions of an SX-SY plane, and couple the first light transmission light B1a and the second light transmission light B1B out of the light waveguide plate SUB1 to form free space transmission light OB3a and OB3B, and the transmission directions of OB3a and OB3B are respectively the same as those of the light engine output light OB0a and OB 0B. The exit pupil unit DOE3 region covers the binocular viewing range of human eyes, and the output light beams OB3a and OB3b contain A, B two parts of image information, and by controlling the position angles of the light engines ENG1 and ENG2 relative to the optical waveguide plate SUB1, the aligned splicing of the output images can be realized, and the display of a complete large-angle expanded image can be realized.

Fig. 7 and 8 show the light transmission when only a single light engine ENG1 or ENG2 is operating, respectively, and fig. 9 is a front view of the pupil expanding device EPE1 according to the present embodiment.

In one embodiment, the optical waveguide plate SUB1 has a thickness of 0.1mm to 3 mm; the length of the exit pupil unit DOE3 is 60-150 mm; the geometric center distances between the first entrance pupil unit DOE1a, the second entrance pupil unit DOE1b and the exit pupil unit DOE3 are all 40mm to 100 mm.

In this embodiment, as shown in fig. 10, the optical waveguide plate SUB1 is an optical waveguide plate that can confine light therein and transmit the light in a total internal reflection manner, and the thickness of the optical waveguide plate SUB1 may be between 0.1mm and 3 mm. The exit pupil DOE3 is a rectangular area, and has a length long enough to cover most of the binocular viewing area of human eyes, and specifically, the length of the exit pupil DOE3 may be 60mm to 150 mm. The first entrance pupil unit DOE1a and the second entrance pupil unit DOE1b are symmetrically distributed on both sides of the exit pupil unit, and a typical shape thereof is circular, square or other shapes, and a typical size thereof may be between 1mm and 15 mm. The first and second pupil expanding units DOE2a and DOE2b correspond to the first and second entrance pupil units DOE1a and DOE1b, respectively, and are used for receiving the image light beams coupled into the optical waveguide plate SUB1 by the first and second entrance pupil units DOE1a and DOE1b, and expanding the light beams to transmit the expanded light beams through the exit pupil unit DOE 3.

As shown in fig. 11, the exit pupil element DOE3 is a two-dimensional grating, and the expansion of the light beam in two directions in the SX-SY plane can be realized. The first and second entrance pupil units DOE1a and DOE1b are symmetrically distributed on both sides of the exit pupil unit DOE3, and the distance between the first and second entrance pupil units DOE1a and DOE1 and b and the geometric center of the exit pupil unit DOE3 may be 40mm to 100 mm.

In a specific embodiment, the first entrance pupil unit DOE1a and the second entrance pupil unit DOE1b have the same grating period and grating direction.

In another specific embodiment, the first and second pupil expanding units DOE2a and DOE2b have the same grating period, and the grating directions of the first and second pupil expanding units DOE2a and DOE2b are mirror-symmetrical.

In one embodiment, the direction of the light beam is analyzed by analyzing the wave vector of the image light beam and the reciprocal lattice vector of the grating.

With reference to figure 12, figure 12 is a wave vector diagram corresponding to a first configuration of the pupil expanding device EPE1 shown in figure 2. The wave vector diagram reflects the angular spectrum information of the image, the change of the grating to the angular spectrum information of the image and the range of the angular spectrum information of the light rays which can be carried by the optical waveguide plate. BND1 denotes a first boundary for meeting the criterion of Total Internal Reflection (TIR) in the optical waveguide plate SUB 1. BND2 denotes the second boundary of the maximum wavevector in the optical waveguide plate SUB 1. The maximum wavevector can be determined by the refractive index of the optical waveguide plate. Light can be guided in the optical waveguide plate SUB1 only if the wave vector of said light is in the region ZONE1 between the first boundary BND1 and the second boundary BND 2. If the wave-vector of the light is outside the ZONE1, the light may leak out of the optical waveguide plate SUB1 or not propagate at all.

Since the ZONE1 region is limited by the finite refractive index and width of the optical waveguide plate SUB1, when the angular spread of the image is too large, the ZONE1 region is insufficient to accommodate the transmission of light throughout the image, and the rectangular region appearing on the wave-vector diagram to represent angular spectral information of the image falls outside the ZONE1 region. The present embodiment solves this problem by splitting the large-angle-broadened image into two small-angle-broadened images and transmitting them separately. As shown in fig. 12 (a) and (B), the wide-angle-spread image is essentially split A, B into two parts, which are transmitted through path a and path B, respectively, and stitched again into a complete image output.

The different-region diffraction gratings affect the propagation of light beams by loading grating vectors on an image angular spectrum even if the image angular spectrum information is translated in a wave vector diagram. The diffraction grating vector V is determined by the grating period (d) and the grating direction (θ) of the area grating. The direction of the grating vector V is vertical to the stripe direction of the diffraction grating, and the amplitude value is 2 pi/d.

As shown in fig. 12, said first entrance pupil unit DOE1a has a grating vector V1a in the negative direction of the SY axis, having a direction θ 1a and a magnitude 2 pi/d 1 a. The second entrance pupil unit DOE1b has a grating vector V1b in the negative direction of the SY axis, with a direction θ 1b and a magnitude of 2 pi/d 1 b. The exit pupil element DOE3 has a grating vector V3 in the positive direction of the SX axis, with a direction θ 3 and a magnitude of 2 pi/d 3. The first pupil expanding element DOE2a has a grating vector V2a in a certain direction θ 2a, with a magnitude of 2 pi/d 2 a. The second pupil expanding element DOE2b has a grating vector V2b in a certain direction θ 2b, with a magnitude of 2 pi/d 2 b. The grating area distribution and the grating vector on the pupil expanding device EPE1 are mirror symmetric about the SY axis. For the path a and the path B shown in fig. 12, the grating vectors satisfy V1a + V2a-V3 being 0 and V1B + V2B + V3 being 0, i.e. the light beam is coupled out from the incoupling optical waveguide plate SUB1 to the incoupling optical waveguide plate SUB1, and the sum of the grating wave vectors in the different regions experienced is 0, i.e. a closed path is formed.

In addition, the grating period d1a and the grating direction of the first entrance pupil unit DOE1a may also be selected such that half of the image angular spectrum information BOX1a diffracted by the grating falls within the ZONE1 area through the first entrance pupil unit DOE1a area, and likewise, the grating period d2a and the grating direction of the first expanded pupil unit DOE2a may also be selected such that half of the image angular spectrum information BOX2a diffracted by the grating falls within the ZONE1 area through the first expanded pupil unit DOE2a area. The grating period d3 and the grating orientation of the exit pupil unit DOE3 may also be chosen such that half of the image angular spectrum information BOX3a that is diffracted by the grating through the area of the exit pupil unit DOE3 returns to the original position, being identical to the image angular spectrum information of the original incident information. Accordingly, the grating period d1b and the grating direction of the second entrance pupil unit DOE1b may be selected such that half of the image angular spectrum information BOX1b, which is grating-diffracted through the area of the second entrance pupil unit DOE1b, falls within the ZONE1 area, the grating period d2b and the grating direction of the second pupil unit DOE2b may be selected such that half of the image angular spectrum information BOX2b, which is grating-diffracted through the area of the second pupil unit DOE2b, falls within the ZONE1 area, and the grating period d3 and the grating direction of the light exit pupil unit DOE3 may be selected such that half of the image angular spectrum information BOX3b, which is grating-diffracted through the area of the exit pupil unit DOE3, returns to the initial position, being the same as the image angular spectrum information of the initial incident information.

In connection with fig. 13, fig. 13 is a wave vector diagram under the proposed second configuration corresponding to the pupil expanding device EPE1 shown in fig. 6. The exit pupil element DOE3 in the pupil expanding device EPE1 shown in fig. 6 is a two-dimensional grating that can provide grating vectors in two directions. As shown in (a) and (b) in fig. 13, for the path a, there are two loops whose grating wave vectors both satisfy V1a-V3a-V3b ═ 0. For path B, there are also two loops symmetrical to path a, and the grating wave vectors of both loops satisfy V1B + V3a + V3B ═ 0. The grating vector size and orientation of the entrance and exit pupil units DOE3 can be chosen such that half of the image angular spectrum information after being processed by a single grating vector in the two entrance and exit pupil units DOE3 falls within the ZONE1 area, i.e. light rays can propagate in the optical waveguide plate SUB1 by total internal reflection, while half of the image angular spectrum information after being processed by two directional grating vectors in said first and second entrance pupil units DOE1a and DOE1b and exit pupil unit DOE3 is returned to the original position.

That is, the sum of all optical element grating vectors experienced by the light from entering the optical waveguide plate SUB1 to exiting from the optical waveguide plate SUB1 is zero.

An embodiment of the present invention further provides a binocular display device, including the pupil expanding device EPE1 and a light engine module as described above, where the light engine module includes a first light engine ENG1 and a second light engine ENG 2;

the first light engine ENG1 provides light to the first entrance pupil unit DOE1a in a direction making a third angle with the normal to the light exit surface of the optical waveguide plate SUB 1; the second light engine ENG2 provides light to the second entrance pupil unit DOE1b along a direction making a fourth angle with the normal to the light exit surface of the optical waveguide plate SUB 1.

The binocular display device provided by the embodiment divides a virtual image with large angle broadening into two virtual images with small angle broadening in half, the two virtual images with small angle broadening are projected and output through two light engines respectively, and are constructed on a single-layer light guide plate, two entrance pupil units are coupled into a light guide plate SUB1 respectively, and the two virtual images with small angle broadening are coupled out by the same exit pupil unit after passing through a pupil expanding in the light guide plate, spliced and fused into an initial virtual image with large angle broadening, and are received by two eyes for imaging. This novel binocular display device nearly twice has expanded the virtual image angular width that current optical waveguide technique can present to realize the binocular simultaneous imaging through the integration of individual layer waveguide, greatly improved the user and immersed the sense and experienced and compromise key parameter such as cost, weight, volume simultaneously.

With reference to fig. 2, the binocular display device implements binocular display of the wide-angle expanded images by splitting, splicing and fusing the wide-angle expanded images, the binocular display device specifically includes two light engines (i.e., the first light engine ENG1 and the second light engine ENG2) and a pupil expanding device EPE1, the first light engine and the second light engine implement projection output of half of the images respectively, and the pupil expanding device EPE1 receives output images of the two light engines and expands and splices the images to implement wide-angle expanded image display covering both eyes. The pupil expanding device EPE1 includes two entrance pupil units and one exit pupil unit, the two entrance pupil units are respectively used for receiving the images projected by the two light engines and respectively forming the first light-conducting light B1a and the second light-conducting light B1B which are transmitted in the waveguide. Both of the entrance pupil cells, which are one-dimensional gratings with grating groove lines along the SX axis direction, grating periods d1a and d1b, respectively, and d1a being equal to d1b, may provide grating vectors V1a and V1b, respectively, of magnitude 2 pi/d 1a (or 2 pi/d 1b) along the SY negative direction. The exit pupil unit is a one-dimensional grating, the area size can cover a binocular eye observation area of human eyes, grating groove lines are along the SY axis direction, the grating period is d3, and a grating vector V3 with the size of 2 pi/d 3 along the SX positive direction can be provided. The pupil expanding device EPE1 further includes two pupil expanding units, and the two pupil expanding units receive the first light transmission guide B1a and the second light transmission guide B1B of the two pupil entering units coupled into the light guide plate respectively, and form a third light transmission guide B2a and a fourth light transmission guide B2B respectively, and the third light transmission guide B2a and the fourth light transmission guide B2B transmit to the region of the pupil exiting unit in opposite directions. The two pupil expanding units are symmetrically distributed on two sides of the exit pupil unit, and grating vectors of the two pupil expanding units are symmetrical about an SY axis. The two pupil expanding units are one-dimensional gratings, the grating periods are d2a and d2b respectively, and d2a is equal to d2b, and the two pupil expanding units can respectively provide grating vectors V2a and V2b with the size of 2 pi/d 2a (or 2 pi/d 2b) and forming a certain included angle theta with the SY axis. And the sum of the wave vectors of the ring-shaped grating is zero when the light rays pass through the entrance pupil, the expanding pupil and the exit pupil. The grating periods d1a, d1b, d2a, d2b, d3, and θ satisfy the relationship:

to obtain

d2a＝d3×sinθ。

Taking path a in fig. 12 as an example to describe the image light propagation process, the incident light OB0a is incident to the first entrance pupil unit DOE1a in an angular spectrum BOX0, the first entrance pupil unit DOE1a area grating couples the incident light OB0a into the optical waveguide by diffraction to form a first light-transmitting light B1a, the first light-transmitting light B1a is transmitted in the optical waveguide plate to the first pupil expanding unit DOE2a by total internal reflection, the first pupil expanding unit DOE2a area grating expands and turns the first light-transmitting light B1a by diffraction to form a third light-transmitting light B2a, and the third light-transmitting light B2a is transmitted in the optical waveguide plate to the exit pupil unit DOE3 by total internal reflection; the third light guide B2a is partially coupled out of the light guide plate by the grating of the exit pupil unit in a grating diffraction mode while being totally internally reflected and propagated in the exit pupil unit area to form a free space light beam OB3a, and is observed by human eyes, the propagation direction of OB3a is the same as that of incident light OB0a, and OB3a can cover the binocular observation range of human eyes after being expanded by the pupil expanding device EPE1, so that binocular imaging of human eyes is realized. ,

as shown in fig. 6, the binocular display device includes two light engines each of which implements a half image projection output, and a pupil expanding device EPE1 which receives the output images of the two light engines and expands and splices the images to implement a large-angle-broadened image display covering both eyes. The pupil expanding device EPE1 includes two entrance pupil units and one exit pupil unit, the two entrance pupil units are respectively used for receiving images projected and output by the two light engines and respectively forming a first light transmission light B1a and a second light transmission light B1B transmitted in the waveguide. The two entrance pupil units are one-dimensional gratings, the grating groove lines are along the SY axis direction, the grating periods are d1a and d1b respectively, and d1a is equal to d1b, and the two entrance pupil units can provide a grating vector V1a with the size of 2 pi/d 1a along the positive direction of SX and a grating vector V1b with the size of 2 pi/d 1b along the negative direction of SX respectively. The exit pupil unit is a two-dimensional grating formed by crossing two-dimensional gratings in two directions, the area size can cover a binocular viewing area of human eyes, the groove line directions of the two one-dimensional gratings are respectively 60 degrees and 120 degrees from the positive direction of the SY axis, the grating periods are respectively d3a and d3b, and d3a, d3b, d1a and d1b are equal. The two one-dimensional gratings may provide a grating vector V3a of magnitude 2 pi/d 3a at 120 deg. from the positive direction of the SY axis and a grating vector V3b of magnitude 2 pi/d 3b at 60 deg. from the positive direction of the SX axis, respectively.

The grating vectors provided by the areas of the pupil expanding device EPE1 are shown in fig. 13, and the grating vectors of the areas are superimposed to present a regular triangular loop. Taking path a as an example, the incident light OB0a enters the first entrance pupil unit DOE1a in the form of an angular spectrum BOX0, the grating in the area of the first entrance pupil unit DOE1a couples the incident light OB0a into the optical waveguide by diffraction to form first transmission light B1a, the first transmission light B1a is transmitted in the optical waveguide plate to the exit pupil unit DOE3 by means of total internal reflection, because the exit pupil unit DOE3 is a two-dimensional grating formed by overlapping two one-dimensional gratings, two-dimensional grating vectors can be provided, one of the two-dimensional gratings of the exit pupil unit DOE3 changes the propagation direction of the first transmission light B1a by means of grating diffraction to form third transmission light B2a, the other one of the two-dimensional gratings of the exit pupil unit DOE3 acts on the third transmission light B2a by means of grating diffraction to form a free-space output light beam OB3a, and is observed by the human eye, the propagation direction of the output light beam OB3a is the same as that of the incident light OB0a, and OB3a can cover the binocular observation range of human eyes after being expanded by the pupil expanding device EPE1, thereby realizing binocular imaging of human eyes.

The embodiment of the invention also provides a binocular display method which is realized by adopting the binocular display device.

The embodiment of the invention also provides an image display method which is realized by adopting the binocular display device.

Since the embodiment of the method portion corresponds to the embodiment of the apparatus portion, please refer to the description of the embodiment of the apparatus portion for the embodiment of the method portion, which is not repeated here.

The embodiments are described in a progressive manner in the specification, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. For the system disclosed by the embodiment, the description is relatively simple because the system corresponds to the method disclosed by the embodiment, and the relevant points can be referred to the method part for description. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.

It is further noted that, in the present specification, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.

Claims (12)

1. The pupil expanding device is characterized by comprising at least one layer of optical waveguide plate, wherein a first entrance pupil unit, a second entrance pupil unit and an exit pupil unit are arranged on the optical waveguide plate, and the first entrance pupil unit and the second entrance pupil unit are symmetrically distributed at two sides of the exit pupil unit; the first entrance pupil unit is used for diffracting first input light incident at a first angle into first transmission light, the second entrance pupil unit is used for diffracting second input light incident at a second angle into second transmission light, and the exit pupil unit is used for diffracting the first transmission light and the second transmission light into output light.

2. The pupil expanding device according to claim 1, characterized in that the exit pupil element is a one-dimensional grating for image expansion and image outcoupling in the corresponding direction, the one-dimensional grating direction being the SY-axis direction ± 10 °.

3. The pupil expanding device according to claim 2, wherein the optical waveguide plate further comprises a first pupil expanding unit and a second pupil expanding unit, the first pupil expanding unit and the second pupil expanding unit are symmetrically disposed on two sides of the exit pupil unit, the first pupil expanding unit is located below the first entrance pupil unit, and the second pupil expanding unit is located below the second entrance pupil unit;

the first pupil expanding unit is used for diffracting the first transmitted light into third transmitted light, and the second pupil expanding unit is used for diffracting the second transmitted light into fourth transmitted light.

4. The pupil expansion device according to claim 1, characterized in that the exit pupil unit is a two-dimensional grating formed by two crosswise arranged one-dimensional gratings providing grating vectors of two directions which sum to 0 the grating vectors of the first or second entrance pupil unit.

5. The pupil expanding device according to claim 1, wherein the first and second angles are different and are symmetrical with respect to the normal to the optical waveguide plate.

6. The pupil expansion device according to claim 1, characterized in that the first and second entrance pupil units have the same grating period and grating direction.

7. The pupil expansion device according to claim 3, characterized in that the first and second pupil expansion units have the same grating period and the grating directions of the first and second pupil expansion units are mirror symmetric.

8. The pupil expanding device according to claim 1, wherein the optical waveguide plate has a thickness of 0.1 to 3 mm; the length of the exit pupil unit is 60 mm-150 mm; the geometric center distances among the first entrance pupil unit, the second entrance pupil unit and the exit pupil unit are all 40-100 mm.

9. The pupil expanding device according to claim 1, wherein the sum of the grating vectors of all optical elements experienced by the light from the entrance to the exit of the light guide plate is zero.

10. A binocular display apparatus comprising the pupil expanding device of any one of claims 1 to 9 and a light engine module comprising a first light engine and a second light engine;

the first light engine provides light to the first entrance pupil unit along a direction making a third angle with a normal vector to the light exit surface of the light guide plate; the second light engine provides light to the second entrance pupil unit along a direction forming a fourth angle with a normal vector of the light-emitting surface of the light guide plate.

11. A binocular displaying method, characterized in that it is implemented using the binocular displaying apparatus of claim 10.

12. An image display method, characterized by being implemented using the binocular display apparatus of claim 10.

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