Holographic diffraction optical coding system

Abstract

Holographic diffractive optical coding techniques for forming reflective or transmissive holograms are disclosed. An encoding device includes a substrate having an interference pattern capable of propagating light from one side of the substrate to the other side of the substrate along a light propagation path. In addition, optical elements can be used to propagate light according to a four-dimensional light field coordinate system.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is a divisional application of Chinese patent application 201980018338.0 (PCT / US2019 / 013523), whose international application date is January 14, 2019 and whose national phase entry date is September 11, 2020, and whose name is “Holographic Diffraction Optical Coding System”.

[0003] This application claims priority to U.S. Provisional Patent Application No. 62 / 617,284, filed on January 14, 2018, entitled “Holographic and Diffractive Optical Encoding Systems,” which is incorporated by reference in its entirety. Technical Field

[0004] The present disclosure relates generally to optical technology, and more particularly to holographic diffractive optical encoding systems for forming reflection or transmission holograms. Background Art

[0005] Holography is a technology that can record a light field and reconstruct it later without the original object. Holography can be thought of as somewhat similar to a sound recording, where a sound field produced by a vibrating substance such as a musical instrument or vocal cords is encoded in a way that it can be reproduced later without the original vibrating substance.

[0006] There are two basic types of holograms: reflection holograms and transmission holograms. Reflection holograms reflect light. When the light used for reconstruction reflects from the interference pattern within the photographic medium, a light field is formed. Transmission holograms transmit light. During reconstruction, the light is diffracted by the hologram. In general, reflection holograms provide the highest quality images, but are the most expensive to produce. Transmission holograms are the most common because they can be mass-produced at low cost in the form of embossed holograms. Credit cards often contain embossed holograms. It should be understood that the embodiments discussed herein can implement either type of hologram, and it should be understood that the techniques for encoding either type of hologram and converting reflection holograms to transmission holograms and converting transmission holograms to reflection holograms are well known in the art and need not be repeated here. Summary of the invention

[0007] Embodiments of the disclosed waveguide may include: a substrate comprising a photographic medium; and an interference pattern encoded in the photographic medium, the interference pattern defining an array of substrate sites in the substrate. The interference pattern is configured to propagate light along a light propagation path extending from a light position on a first side of the substrate toward a second side of the substrate. The light propagation path includes a plurality of groups of light propagation paths extending through a same substrate site and a same light position, wherein each group of light propagation paths is configured to extend substantially in a unique direction on the second side of the substrate and converge from the same substrate site to the same light position on the first side of the substrate, the unique direction being determined by the angular direction of the principal ray propagation paths in each group of light propagation paths. Thus, the array of substrate sites is configured to propagate light according to a four-dimensional light field coordinate system including spatial coordinates defined by the positions of the substrate sites and angular coordinates defined by the unique directions of the plurality of groups of light propagation paths for each substrate site.

[0008] In an embodiment, the light field is encoded as an interference pattern of the photographic medium. When properly illuminated, the interference pattern diffracts light into a reproduction of the original light field, and objects therein appear to still exist, thereby exhibiting visual depth cues such as parallax and perspective that realistically change with any change in the relative position of the observer. Photographic media including photographic emulsions may include dichromated gelatin, photoresists, photothermoplastics, photopolymers, and photorefractives, among others.

[0009] In another embodiment, a waveguide array may include: a substrate including a photographic medium; an interference pattern encoded in the photographic medium, the interference pattern defining an array of substrate sites in the substrate, each substrate site including a plurality of substrate subsites; and an optical element defining an array of optical element sites corresponding to respective substrate sites, each optical element site including a plurality of optical element subsite positions. The interference pattern is configured to propagate light along a light propagation path extending through the substrate subsite of each substrate site to an optical element subsite position of the respective optical element site, wherein the light propagation path includes a plurality of groups of light propagation paths extending through the same optical element site and the same substrate subsite of the respective substrate site. Each group of light propagation paths generally extends from the optical element away from the substrate in a unique direction and converges from different optical element subsite positions of the same optical element site to the same substrate subsite of the respective substrate site, the unique direction being determined by the angular direction of the principal ray propagation paths in each group of light propagation paths. Thus, the array of optical element sites is configured to propagate light according to a four-dimensional light field coordinate system that includes spatial coordinates defined by the positions of the optical sites and angular coordinates defined by the unique directions of the multiple sets of light propagation paths for each optical site. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram of a holographic microlens array ("HLA") locus;

[0011] Figure 2 is a diagram of the corresponding HLA and illumination source array ("ISA") sites;

[0012] Figure 3 is a graphical representation of the coordinate system of the HLA and ISA loci;

[0013] Figure 4 is a diagram of another coordinate system for HLA and ISA loci;

[0014] Figure 5 is a diagrammatic representation of the geometry of the HLA and ISA loci;

[0015] Figure 6 is a graphical representation of the coordinate system of the HLA and ISA loci;

[0016] Figure 7 is a graphic representation of the chief ray angle of the ISA subsite location;

[0017] Figure 8 is a diagram of the principal ray propagation paths of the HLA subsite locations;

[0018] Fig. 9 is a diagram of a common input reference beam angle for one ISA subsite position and multiple HLA subsite positions;

[0019] Fig.10 is a graphical representation of the object beam angle for one ISA subsite location and multiple HLA subsite locations;

[0020] Fig.11A and B are graphical representations of the reference beam angle and the object beam angle;

[0021] Fig.12 It is a perspective illustration of the reference beam angle and the object beam angle in three dimensions;

[0022] Fig.13 is a graphical representation of exemplary encoding parameters of an interference pattern of the present disclosure;

[0023] Fig.14 is a diagram of a first embodiment of encoding an interference pattern according to the present disclosure;

[0024] Fig.15 is a diagram of a second embodiment of encoding an interference pattern according to the present disclosure;

[0025] Fig.16 is a diagram of a third embodiment of encoding an interference pattern according to the present disclosure;

[0026] Fig.17 is a diagram of the direct HLA encoding hypothesis;

[0027] Fig.18 is a diagram of the convergence of light at the location of the ISA subsite;

[0028] Fig.19 is an illustration of the correct convergence at the virtual HLA element;

[0029] Fig. 20 is an illustration of an uncorrected virtual HLA playback;

[0030] Fig.21 is the icon of the virtual HLA to be played;

[0031] Fig. 22 is a graphical representation of a diffractive optical element ("DOE") correction;

[0032] Fig.23 is a graphic representation of the virtual HLA playback after DOE correction;

[0033] Fig.24 is a diagram of the encoding at the virtual HLA plane;

[0034] Fig.25 is a diagram of the ISA reference beam encoding;

[0035] Fig.26 is a diagram of the ISA illumination source reconstruction;

[0036] Fig. 27 is a diagrammatic representation of an embodiment of a DOE site;

[0037] Fig.28 is a graphic representation of the coding considerations for large ISA loci; and

[0038] Fig.29 is a diagram of a multi-element DOE HLA optical system. DETAILED DESCRIPTION

[0039] Embodiments according to principles of one aspect of the present disclosure may include two different planes - a holographic microlens array (referred to herein as "HLA"), which may include interference patterns encoded in a photographic medium and defining many different holographic elements; and an illumination source array (referred to herein as "ISA"), which may be positioned below the HLA. The HLA elements may be divided into NxM subsites at the locations of the HLA subsites, respectively. One aspect of the present disclosure describes encoding for these subsites, so the HLA elements generally act as a lens array. Embodiments according to principles of another aspect of the present disclosure may include encoded interference patterns configured to direct light to an optical element having optical element subsites similar to the HLA subsites, similar to the ISA.

[0040] Turning to the embodiment of the HLA 100, Figure 1 , HLA 100 may include a plurality of HLA elements 102, each of which includes a separate digital hologram encoded to substantially reproduce the properties of a theoretically perfect lens. These holograms may have a digitally constructed optical profile whose functionality is not subject to the limitations associated with microscopic optical elements.

[0041] Turning to the embodiment of ISA 200, Figure 2 , the ISA includes multiple light sources that direct light to corresponding locations on the HLA site 102.

[0042] In an embodiment, the HLA and ISA planes are each subdivided into a plurality of positions, referred to as sites. In an embodiment, each site can be independently encoded. The HLA and ISA sites can have regular, irregular or overlapping configurations. Figure 1 A diagram showing the HLA locus 102 is shown.

[0043] In an embodiment, the HLA and ISA sites may be packed into regular rectangles with overlapping regions between the ISA sites, such as Figure 2 It should be appreciated that other designs according to the principles disclosed herein can be used and are contemplated in the present disclosure.

[0044] The desired number of HLA and ISA sites per display defines the visual resolution of the display and the size of each physical site, as defined by:

[0045]

[0046] I w =H W *(1+O X ),I H =H H *(1+O Y )

[0047] Among them, H WH and I WH are the physical width and height measurements of each HLA and ISA locus, respectively, and D WH is the total width and height of the entire display surface, DN XY is the total number of individual HLA loci in the vertical and horizontal dimensions relative to the overall HLA display surface, and XY is the overlap factor that takes into account the fact that each ISA region may be larger than its corresponding HLA region. Figure 1 and 2 For non-zero O XY, an illumination source located in the overlapping region of an ISA may act not only on the HLA directly above it, but also on at least one adjacent HLA.

[0048] Irregular configurations can be determined using more advanced calculations.

[0049] Place the locations of the HLA and ISA loci pairs containing the cocenter in a canonical coordinate system that can be indexed by the variable i in the x-direction and j in the y-direction:

[0050] HLAH ij <=>ISAI ij

[0051] like Figure 3 As shown, the origin i,j=0,0 is located at the center of the display. The range of values ​​of i and j is

[0052]

[0053] For simplicity, HLAH ij and ISAI ij The pair will be collectively referred to as HI ij .

[0054] H ij &I ij Yes <=>H ij

[0055] HI ij Each position represents a W xD H A single optical element 300 within the overall display system includes corresponding HLA and ISA loci.

[0056] D W xD H Different W, H values ​​can be presented across the surface of the display system and can be expressed as a function of index position.

[0057] Proper consideration is given to even, odd, and non-integer DNs XY Value, where HI 00 Not in the center of the HLA locus, HI ij The coordinates can be obtained by considering Figure 4 HI′ shown in ij To establish, where HI′ 00 Starting from the lower left HLA position on the display surface and incrementing such that

[0058] i′=0→(DN X -1),j′=0→(DN Y -1)

[0059] These two coordinate systems HI ij and HI′ ij The indices are related to each other by simple offsets:

[0060]

[0061] Taking into account the optical center of each HLA, it is possible to calculate each HI with reference to the display origin. ij The exact location of the center of the component.

[0062] HI ij x c =i*HLA w

[0063] HI ij y c =j*HLA H

[0064] Considering the coordinates of the holographic lens array, each HI in the coordinate system ij Site 300 may now contain an additional subsite coordinate system defined by N subdivisions on the x-axis and M subdivisions on the y-axis. ij Both the ISA and HLA loci of site 300 are subdivided into NxM individual regions. To completely specify a set of coordinates for the HI element, the following notation is used:

[0065] HI ij n H m H n I m I

[0066] Here, ij is the index of the ISA and HLA locus of the HLA element, and n H m H represents the index of the HLA sublocus of the HLA locus, and n I m I Represents the index of the ISA subsite of the ISA site.

[0067] like Figure 5 As shown, by making HI ij The size of each HLA subsite is determined by dividing the width of the HLA site 502 of the HLA optical element 500 by N on the x-axis and dividing the height of the HLA site 502 by M on the y-axis. ij The width and height of the ISA site 504 of the HLA optical element 500 define the size of the ISA subsite.

[0068]

[0069]

[0070] Each HLA and ISA sublocus may exhibit different values ​​for different loci and may be expressed as a function of the index position.

[0071] HLA and ISA can have different sizes, but share the same ij The common (0,0) point at the center of the HLA optical element. H m H n I m I Subsite indexing can be processed in the same way as ij HLA element indexing above, such that

[0072]

[0073] Each HI ij The HLA and ISA subsites at the positions share the same N x M coordinate system, but may have different physical locations between planes outside the central axis, where n I =m I =n H =m H =0.

[0074] The physical position of a particular HLA subsite in units of length is given by:

[0075]

[0076] Similarly, the physical position of a particular ISA subsite in units of length is given by:

[0077]

[0078] Each index can be constrained to be an integer or an integer -.5. We find that another coordinate system can be defined, where (n H ,m H )=(0,0) is not located at the center of the HLA subsite. This coordinate system is Figure 6 As shown, represented by HI′ ij n H m H n I m I , where (0,0) is at the lower left corner of the subsite. In this coordinate system, the subsite position index has the following range.

[0079] n′ H =0→(N-1),m′ H =0→(M-1)

[0080] n I′=0→(N-1),m I ′=0→(M-1)

[0081] in

[0082]

[0083] It should be noted that all of the above assumes that the configuration of the HLA and ISA sites is uniform and regular, but such a configuration should not be understood as required. It should be understood that the principles of the present disclosure can be applied to other configurations of the HLA and ISA sites, as contemplated herein.

[0084] The distance 706 between the parallel HLA plane 702 and the ISA plane 704 is denoted as f. This parameter is designed to provide a ij The field of view (“FOV”) and chief ray angle (“CRA”) of any ISA subsite are controlled. CRA is the I ,m I Connect to HLA element H ij The centers of the HLA loci are equally indexed (n H ,m H )=(0,0) limit, such as Figure 7 as shown in .

[0085] The maximum full FOV angle for each HLA is determined by:

[0086]

[0087] The CRA half angle formed between the center of the HLA locus and the ISA subsite position is the ISA subsite position coordinate and a function of parameter f.

[0088]

[0089] It should be noted that for n I ,m I For each ISA subsite position defined, there are different CRAs, such as Figure 8 As shown in this figure, this figure illustrates a set of CRA angles for the corresponding HLA locus H ij Each ISA subsite position (n I ,m I ) shows a CRA angle. H ,m H ) = (0,0), the input reference beam angle equals the output object beam angle (assuming a system in which there is an equal step between each of the formed CRA angles, uniformly sized HLA subsites, and uniformly sized ISA subsites).

[0090] Both CRA angles and HLA / ISA sites may be defined by irregular intervals or angles of more complex optical configurations, and it will be appreciated that the principles of the present disclosure may be applied to these configurations as contemplated herein.

[0091] In an embodiment, each individual HLA locus H ij The code is as follows:

[0092] A) For each ISA subsite position The associated CRA defines a central ray that sets the HLA locus H ij A single common input reference beam angle for each of the NxM HLA subsite locations, such as Fig. 9 In other words, for a given (n I ,m I ), all input reference beam angles are the same.

[0093] B) from each HLA sublocus position Each ray should converge at the ISA subsite position On, such as Fig.10 This set of rays forms the output object beam angle for each of the NxM HLA subsite locations.

[0094] C) The angle of each ray between the ISA and HLA planes is the ISA coordinate HLA coordinates and the distance f between the HLA and ISA planes.

[0095]

[0096] D) For a I ,m I ), there will be NxM output reference beam angles for each ISA subsite position. Since there are NxM ISA subsite positions, each HLA-ISA pair requires N 2 xM 2 An input reference-output object angle encoding pair.

[0097] E) has DN x xD y The entire display of HLA elements will require a x xD y xN 2 xM 2 The θ coordinate system encodes an input reference-output object angle pair.

[0098] Fig.11A and11B It can be shown that the coordinates I ij The two different ISA subsite positions 1102 and 1104 of the same ISA site 1106 may have coordinates H ij Encoding pairs of different subsite positions of HLA locus 1108. Fig.12 A three-dimensional view of an encoded pair showing a single ISA subsite position 1206 and a single HLA site 1204. The ISA subsite position 1206 may have a CRA defined by a principal ray propagation path 1208.

[0099] exist Fig.13 An embodiment is provided as Example A to illustrate the principles of the present disclosure. In Example A, the illumination source assumptions to be considered may include the following:

[0100] ● Bayer RGB, non-laser, diffuse illumination source plane

[0101] ●Diffusing surface for HOE focusing

[0102] ●Must be visible white light

[0103] ● Transmissive element between the observer and the illumination source

[0104] In Example A, the single HOE encoding exceeds the current state-of-the-art (SOTA) HOE encoding method. The SOTA process limitations include:

[0105] ●100um 2 The minimum subsite encoding size of

[0106] ●One reference angle every 10 degrees The maximum value of the multiplexing effective transmission is reduced (Please confirm assumption)

[0107] 1 / L effective transmission (or less), where L = number of multiplexed lambdas

[0108] Given the above discussion of the structural relationship of HLA and ISA sites and subsites and the encoding of the HLA site for multiple ISA subsite locations in the ISA site, one of ordinary skill in the art will appreciate that the principles of aspects of the present disclosure may be implemented into waveguides.

[0109] In an embodiment, a waveguide of the present disclosure may include: a substrate comprising a photographic medium; and an interference pattern encoded in the photographic medium such that the interference pattern defines an array of substrate sites in the substrate. In an embodiment, the interference pattern includes a hologram encoded to guide light as an array of microlenses, thereby forming a holographic microlens array ("HLA"), as discussed above. The HLA may include a plane subdivided into sites, such as the sites Hij discussed above. The HLA sites correspond to substrate sites. In addition, the interference pattern of the substrate may be configured to propagate light along a light propagation path extending from a light position (e.g., an ISA sub-site position) on a first side of the substrate (e.g., an HLA site Hij) toward a second side of the substrate (e.g., an HLA site Hij). As discussed above, Figure 10-12 An example of a light propagation path is shown in FIG.

[0110] In an embodiment, the light propagation paths include multiple groups extending through the same substrate site (e.g., Fig.11A and 11B HLA locus 1108 in, or Fig.12 HLA locus 1204 in the same optical position (e.g., Fig.11A and 11B ISA subsite positions 1102 and 1104 in or Fig.12 ISA subsite locations 1206 in the substrate, wherein each set of light propagation paths is configured to extend substantially in a unique direction on the second side of the substrate, such as Fig.10 As shown in , and converges from the same substrate site to the same light position on the first side of the substrate. Fig.10 As shown in , a unique direction is determined by the angular direction of the principal ray propagation path in each set of light propagation paths.

[0111] In an embodiment, as described above with respect to Figure 7-9 As discussed, principal ray propagation paths include light propagation paths between one of the ISA subsite locations and the center of the corresponding subsite of the HLA. The unique direction of each set of light propagation paths is determined by the principal ray angle ("CRA") of the corresponding principal ray propagation path. Thus, the array of substrate sites is configured to propagate light according to a four-dimensional light field coordinate system including spatial coordinates and angular coordinates, wherein the spatial coordinates are determined by the substrate sites (e.g., Fig.11A and 11B HLA locus 1108 in, or Fig.12 The angular coordinates are defined by the locations of the HLA sites 1204 in the substrate, and the angular coordinates are defined by the unique directions (e.g., CRA) of the multiple sets of light propagation paths for each substrate site location.

[0112] In such Figure 10-12In the illustrated embodiment, for each ISA sub-site position of the first site of the ISA, the corresponding site of the HLA in the interference pattern is encoded with a common input reference beam angle or an output object beam angle, wherein the common input reference beam angle is determined by the CRA of the corresponding principal light propagation path of each ISA sub-site position, and the output object beam angle is determined by the light propagation path that converges from the HLA sub-site position in the corresponding site of the HLA to each ISA sub-site position of the first site of the ISA.

[0113] In an embodiment, the encoding method for encoding the HLA loci assumes that for each N x M input reference angle, there are associated N x M output object angles as defined in the discussion above, where a single beam is split into reference and object beams as is typically performed with holographic encoding methods. Fig.14 As shown, for the first site 1402 of the ISA and the corresponding site of the HLA 1404, one of the corresponding HLA sub-site positions 1406 is simultaneously encoded with a pair of common input reference beam angles 1410 of a single corresponding ISA sub-site position 1408 and one of the output object beam angles 1412 of the single corresponding ISA sub-site position 1408.

[0114] It should be understood that although the illustrations of the present disclosure, e.g. Fig.14 , the opposite side of the object beam or reference beam from below can be illustrated, thereby representing a reflection hologram, etc., but it can be easily understood by those skilled in the art that the illustrations provided herein are intended only to illustrate the principles of the present disclosure and are not intended to be limiting. Based on the principles disclosed or demonstrated in the present disclosure, it should be easily understood by those skilled in the art that the embodiments in the present disclosure do not necessarily have the explicit orientation illustrated, and the encoding method of the present disclosure can be implemented using the same / similar side, edge, off-axis embodiments that implement transmission, volume, edge lit, grating, diffraction, refraction, etc.

[0115] Those skilled in the art will appreciate the additional optics, motor control systems, and photons involved in encoding photosensitive polymers, as mentioned in this disclosure.

[0116] Fig.14 The encoding method may include associated hardware known in the art for reflective, transmissive and / or stereo holographic photopolymer media, etc., and provides the most flexible but also the most time-consuming optical digital encoding configuration when there is a one-to-one mapping between input and output light rays.

[0117] In this system, the reference and object beams are directed so that they pass through The light spot size is H Wijnm ,H Hijnm, where the beam and / or optical device rotates about an axis, as depicted in the above-mentioned figures, but not limited to this.

[0118] However, given the exemplary 1.731 x 1.731 mm 2 The HLA element size above the SOTA limit will achieve 33% transmittance per color and about 289 (17 2 ) encoded HLA subsites with a single reference beam per wavelength.

[0119] In comparison, Example A provides a 27 x 40.5 um subsite encoding size and 2,741.3 (64.125 x 42.75) encoded HLA subsites.

[0120] In addition, each HLA subsite can be configured to provide a unique output angle for each of the N x M reference angles. However, SOTA only provides up to 36 (6 2 ) reference angles, at the expense of 1 / 36 effective transmission times 1 / 3 the multiplexed RGB transmission reduction, so that each observed sub-site has only approximately 1% transmitted illumination for a portion of the desired encoded information.

[0121] Alternatively, for a more efficient encoding method, multiple HLA or ISA subsite positions can be encoded simultaneously by creating an offset optical system that produces the desired effect of HLA encoding. Due to the functionality of the encoding system, this can be performed in one of two different ways.

[0122] In an embodiment, Fig.15 For each possible ISA subsite position 1506, Multiple HLA subsite locations 1504 of the HLA locus 1502 are encoded using a common input reference beam angle 1512 and a corresponding plurality of output object beam angles 1510. This operation is repeated for the other ISA subsite locations 1506 in the ISA locus 1508. This method may rely on manufacturing methods to appropriately direct the beam to each HLA subsite. ij n H m H n I m I Optical devices for subsite locations. This encoding process is repeated for each of the NxM ISA subsite locations possible given the photopolymer angular response and / or the encoding system minimum subsite size. This method can be implemented with an optics system having an orientation that aligns the optical CRA with the encoded CRA, or alternatively an off-axis optical path, where the optics remain parallel to the HLA plane and the rays are oriented so that they are offset from within the larger entrance pupil and focused according to the focal point of the optical system, which produces the same beam steering required for the encoding process without the keystoning associated with converged optics.

[0123] In an embodiment, Fig.16 , one of the HLA subsite locations 1602 of the HLA locus 1604 is simultaneously encoded with a plurality of common input reference beam angles 1610 of a plurality of ISA subsite locations 1606 of the ISA locus 1608 and a corresponding plurality of output object beam angles 1612 of the corresponding plurality of ISA subsite locations 1606. This process is repeated for the other HLA subsite locations 1602 with corresponding focused object beam rays. This method can be implemented using offset optics designed to focus at a single subsite location, wherein the resulting angles accurately reconstruct the angles at the specified HLA subsite location, ISA n H 、m H The desired angle formed between the subsite positions and the desired reference angle defining the desired HLA subsite FOV. For exemplary purposes only, the optical elements are shown here as folded. The reference beam angle may be further defined or limited by the photosensitive polymer response.

[0124] It should be understood that although the illustrations of the present disclosure, e.g. Fig.15 and 16 , the opposite side of the object beam or reference beam from below can be illustrated, thereby representing a reflection hologram, etc., but it can be easily understood by those skilled in the art that the illustrations provided herein are intended only to illustrate the principles of the present disclosure and are not intended to be limiting. Based on the principles disclosed or demonstrated in the present disclosure, it should be easily understood by those skilled in the art that the embodiments in the present disclosure do not necessarily have the explicit orientation illustrated, and the encoding method of the present disclosure can be implemented using the same / similar side, edge, off-axis embodiments that implement transmission, stereo, edge light, grating, diffraction, refraction, etc.

[0125] Use actual optics instead of the ones described Fig.14 The brute-force method of will not only limit the accuracy of the encoding process to the accuracy of the motion control hardware, but also to the accuracy of the optical system itself. However, the brute-force method involves up to N 2 x M2 Code exposure, and Fig.15 and 16 The offset optics methods in all involve only N x M coded exposures, since the input and output angles are paired for each exposure. Fig.15 In , all HLA sublocus are encoded simultaneously for each CRA, and in Fig.16 In , all angles are encoded simultaneously for each HLA sublocus.

[0126] Each of these embodiments provides conversion to an appropriate transmissive and / or stereoscopic hologram to produce the desired optic effect.

[0127] The above encoding methods may be limited by the maximum density of encoding sites in the photopolymer.

[0128] Virtual HLA code:

[0129] In addition, it is possible to decouple the ISA and HLA planes by encoding for a virtual plane. This can be considered either the HLA or ISA plane, and the following disclosure will focus on the virtual HLA plane and the physical ISA encoding process, which is for exemplary purposes only.

[0130] In the previous discussion, it was assumed that the HLA loci were encoded for both input and output angles, thus forming a pair N 2 x M 2 The requirement to encode the positions of the individual HLA sublocus locations.

[0131] However, this assumes that for each H ij n H m H n I m I The HLA subsite positions, the input reference rays converge, and the output object rays are paired from the HLA ij n H m H n I m I Coordinate pair diffraction, such as Fig.17 as shown in .

[0132] When repeated for all subsite positions, this forms all the H required for each optical element. ij n H m H n I m I Input reference angle and output object angle. However, the disadvantage of this is that each HLA subsite requires N 2 x M 2This complicates the replication process by requiring multiple reference beam angles. Direct encoding is the most straightforward approach because this plane is the convergence point required for the optical element and can directly replace almost any other form of optical element.

[0133] However, when given H ij n I m I When coordinate tracing the converging rays from the ISA plane to the HLA plane, the required input reference angles defined by the CRA can be considered as identical parallel rays, rather than as Fig.18 The different converged and diffracted rays shown, Fig.18 Show that for Fig.17 Showing the same n,m coordinates but now converging on the ISA plane, the optimized input reference rays are now all considered as parallel rays on the virtual HLA plane rather than converging and diffracted rays.

[0134] Therefore, the encoding process can be simplified to allow a single reference beam angle to encode the necessary angle required for proper focusing on the virtual HLA plane.

[0135] Example encoding method

[0136] If encoded with respect to the destination convergence position at the ISA plane, it is possible to use only a single reference beam steering and offset optics to converge the light at the desired HLA subsite location to form a virtual HLA plane.

[0137] It should also be noted that each ISA site can exhibit a greater I Wijnm ,I Hijnn The physical size of the subsite. If the OXOY over-scan value is 1,1, then it is the corresponding coordinate position H Wijnm ,H Hijnm Given in Fig.13 According to the example values ​​provided in , each ISA subsite is approximately 54x81um, while the HLA subsite size is 27x 40.5um. Using the virtual HLA encoding method on the ISA plane, the SOTA encoding technology can almost produce the desired encoding density.

[0138] Using this method, it is possible to Fig.19 All rays converge at the HLA plane exactly as shown, but will no longer be diffracted to the correct Enter the reference angle, because when the rays converge exactly on the HLA plane, they are unconstrained and no longer diffract, as Fig. 20 shown.

[0139] For some applications, Fig. 20The above uncorrected result highlighted in may be sufficient, and taking into account possible visual distortions, it can be compensated using the originating image source.

[0140] However, for most applications, it is desirable to closely maintain the ij n H m H n I m i The accurate angle formed to ensure proper observation image quality, such as Fig.21 as shown in .

[0141] In order not to increase N 2 x M 2 To achieve this without having an encoded HLA correction angle, an optical element such as a lens or a relatively simple diffractive optical element ("DOE") can be added that exhibits multiple angular variances across the optical surface in order to more accurately diffract light to the desired angle outside the HLA plane. The manufacture of these DOEs can be performed by several different DOE manufacturing methods known in the art. It should be understood that although the embodiments herein may be discussed with reference to DOEs, it should be understood that the present disclosure contemplates embodiments in which the DOE can be replaced by other optical elements such as lenses to achieve the same optical effect.

[0142] Using this simplest approach, the DOE has a diffraction value specified for each of the virtual N x M HLA subsite positions. ij n H m H Subsite positions are simultaneously corrected from ISAI ij All N xM output object corners.

[0143] For each H ij n H m H Subsite location structure of a single Correction value, φ diffraction element for all n I m I Position to achieve almost uniform Input the reference angle. While this simplistic approach (with only a single diffraction value per subsite position) cannot correct for every angle conceivable within the specified optical requirements, the accuracy achieved through this approach is significantly improved to a more ideal state.

[0144] For the given value to be corrected The correction applied at each subsite position can be formed by generating an angle that divides the angle between ±(n I m I ) and from nI m I to-n I -m I n H m H The angle formed between them, where for each virtual n H m H The corrected optical prescription for the subsite location calculation is

[0145]

[0146] in φ′ represents the angle that will be applied to each defined when calculating the resulting angle between the two optical elements. The correction angle is applied to each H ij n H m H subsite, and the resulting diffraction angle produced is φ″ is calculated by the following formula

[0147]

[0148] Throughout this discussion, it is often easier to refer to each ±(n HI m HI ) position, where

[0149] n″ H =-1→1,m″ H =-1→1

[0150] n″ I =-1→1,m″ I =-1→1

[0151] as well as

[0152]

[0153] In general, choose a A DOE correction target midway between the maximum and minimum positions on the surface will minimize the negative impact of compensation at 0 and maximum angles, while n″ H =0,m″ H A DOE correction at n″ = 0 will produce the most accurate results at angles observed perpendicular to the optic surface, but will produce the most accurate results at angles observed perpendicular to the optic surface. H = ±1,m″ H = ±1, the deviation from the prescription is greater, and vice versa. H = ±.5,m″ H = ±.5, the correction applied is within the entire The range is generally the most acceptable. This is not always the expected result and will vary depending on the specific application, and any combination of correction factors may be applied as required.

[0154] To help further clarify these corrections, given the particular complexity of this DOE design, given all H ij n′ H m′ H In the specified single I ij n I m I Position pair n″ H = ±.5,m″ H = ±.5, the following table helps to illustrate the uncorrected angle, the "perfect" lens prescription envisioned in the above HLA disclosure, and each H ij n H m H Subsite location DOE correction factors and corrected angles taking into account the individual subsite correction elements.

[0155] Fig. 22 is an exemplary table to help illustrate the uncorrected virtual HLA angles that would be formed when generating a HOE of the ISA plane (e.g., a photographic medium encoded with an interference pattern), the angles specified as a perfect lens, the DOE correction factors applied to each subsite position, and the resulting angles formed when the DOE correction is applied. It is hopefully clear that while these angles are not perfect, they are close to the ideal goal even when only a single correction prescription is applied. All of the above values ​​should be considered exemplary only, as each specific application requires different considerations. Consider and solve Fig.13 The value stated in for n″ H = ±.5 target DOE correction, these values ​​represent the ISA plane n I ′=48, and produces Fig. 22 The following data matrix

[0156] Fig.23 is a diagram showing the virtual HLA playback after correction using the DOE correction element at the virtual HLA plane. In the case where each n, m virtual HLA subsite position has only a single DOE correction optical value, it is possible to correct the virtual HLA to approximately HLA ij n H m H n I m I The exact angle specified. Fig. 20 The uncorrected virtual HLA rays shown in the figure are compared to the corrected The light rays show the CRA formed by the system The accuracy of defined parallel rays has been significantly increased and is very close to Fig.21 The optical prescription of the system shown in .

[0157] In an embodiment, Fig.23 The correction shown in FIG. 1 can be implemented with an interference pattern encoded into the guided light and an optical element configured to guide the light, the interference pattern being similar to that of the reference Figures 8 to 12 The ISA discussed above has optical components similar to those of reference Figure 8-12 In an embodiment, the interference pattern may define a region in the substrate similar to the reference region. Figure 1-12 An array of substrate sites of the ISA sites discussed, each substrate site comprising a plurality of substrate sub-sites (similar to the ISA sub-sites). The optical element may define a substrate sub-site similar to the reference Figure 1-12 An array of optical element sites of the HLA sites discussed, each optical element site corresponding to a respective substrate site, each optical element site comprising a plurality of optical element sub-site positions (similar to the HLA sub-site positions), the optical element and the interference pattern being configured such that each set of light propagation paths extending through the same optical element site and the same substrate sub-site of the corresponding substrate site generally extends from the optical element away from the substrate in a unique direction and converges from different optical element sub-site positions of the same optical element site to the same substrate sub-site of the corresponding substrate site, the unique direction being determined by the angular direction of the principal ray propagation paths in each set of light propagation paths.

[0158] Fig.24 is a diagram of an embodiment of a method for encoding an ISA site 2402, wherein n of the ISA site 2402 is I The subsite positions are encoded using a reference beam from below and an object beam of angled collimated light based on the desired CRA angle defined by the ISA subsite positions. The reference optics may or may not exhibit an angle and may or may not include offset coded light.

[0159] As previously discussed, it should be understood that although the illustrations of the present disclosure, e.g. Fig.23 and 24 , the opposite side of the object beam or reference beam from below can be illustrated, thereby representing a reflection hologram, etc., but it can be easily understood by those skilled in the art that the illustrations provided herein are intended only to illustrate the principles of the present disclosure and are not intended to be limiting. Based on the principles disclosed or demonstrated in the present disclosure, it should be easily understood by those skilled in the art that the embodiments in the present disclosure do not necessarily have the explicit orientation illustrated, and the encoding method of the present disclosure can be implemented using the same / similar side, edge, off-axis embodiments that implement transmission, stereo, edge light, grating, diffraction, refraction, etc.

[0160] Using this encoding method, the mechanical and optical processes are much simpler, where the object beam (now located above the HLA plane) relies on only one element to accurately focus and converge the light on the desired ISA plane based on the CRA and using parallel rays that can fill the entrance pupil of the optical element to produce the specified required angle. The optics do not necessarily need to be moved, but the collimated beam can be accurately oriented to meet the angle required by the CRA. The reference beam optics (now below the ISA plane) are much simpler and do not necessarily need to be tilted in any particular way, as these positions now represent the illumination plane as a diffusely illuminated surface. Depending on the characteristics of the encoding system, these beams can be offset, perpendicular and / or tilted.

[0161] Considering the illumination surface for playback, it is possible to generate a set of divergent light rays that simulate the behavior of a given light source. In one embodiment, when the light rays pass through the focal point of the converging optical assembly and generate a holographic optical element sub-site H, the holographic optical element sub-site H is confined to the holographic optical element. Wijnm ,I Hijnm When a range of illumination angles are applied, the coded reference optics (or the object beam of all previous disclosures) can intentionally generate a range of angles, such as Fig.25 As discussed elsewhere in this disclosure, a holographic optical element may include a substrate comprising a photographic medium encoded with an interference pattern and Fig.25 In an embodiment of the present invention, the encoded interference pattern includes a substrate site 2502 having sub-sites 2504.

[0162] On a display with a given illumination source 2602, the encoded angles will now accurately reconstruct the encoded object beam without the need for Fig.26 Laser illumination source shown.

[0163] Other optical configurations are included depending on the profile of the illumination pixel and may include multiple smaller elements, different focal lengths, apertures, offsets and / or various other optical reconfigurations to precisely reduce the requirement for collimated light to appropriately use the HOE element.

[0164] Additionally, other DOE elements may be utilized at the illumination source to more accurately produce nearly collimated light from an incoherent / non-collimated illumination source. For example, a micro-Fresnel or kinoform element may be utilized.

[0165] It is possible to divide each DOE subsite position into d x d y This is used to pass the n-based H m HAdditional functions of coordinates modify the above DOE correction mathematics and / or add additional DOE optical elements before or after the virtual HLA plane to further improve the accuracy and bring it closer to the original optical prescription.

[0166] Assuming that the virtual HLA spot size is smaller than the HLA subsite itself, we can also use d x d y Subdivision correction method, where individual DOE elements are offset below or above the virtual HLA plane. With this offset, it is possible to diffract light that is not yet converged (below) or just beyond convergence (above) at the desired HLA plane, producing light that is now distributed in the HLA plane. ij n H m H The light is then distributed over a larger spatial distribution within the subsite location and encoded by a DOE plane with only a single element or a multi-element DOE. x d y Subdivisions provide additional control.

[0167] The most straightforward approach is to place the HOE above the virtual HLA plane to handle potential diffraction errors, where the resulting subdivision can be expressed as

[0168] HI ij n H m H d x d y

[0169] Each of d x d y The coordinates represent the local coordinate system of each nH, mH subsite, resulting in an offset position that is roughly the position where the converging rays from the virtual HLA plane first intersect the adjacent subsite rays, such as Fig. 27 Described in. Fig. 27 An exemplary multi-element DOE correction element is shown, where the first element 2702 and the second element 2704 are separated by a distance H. D , showing that the second element DOE subdivisions of Ox and Oy are co-located at the distance, where each n H Light converges between adjacent subsite locations.Alternative locations 2706 for the second element DOE are also shown.

[0170] Using similar considerations as performed with a single DOE correction recipe, the same logic can be applied to the multi-element design described above, where the correction factor can be obtained by adding d x d y Subsite positions were used to optimize additional corrections.

[0171] Other correction opportunities include using the latest SOTA angle reuse method to convert each virtual Hij n H m H The subsite locations are holographically encoded as subdivided exit angles. In this way, the correction application can be varied based on the entrance angle (as defined from the ISA plane to the DOE element) and different corrections applied based on the entrance angle. This can be performed as a single element with a DOE element, or as a different multi-element optical design.

[0172] ISA>HLA Regional Considerations

[0173] Furthermore, it should be noted that the complexity of encoding the ISA HOE is higher when encoding an ISA region that is larger than the HLA region. In this case, some illumination plane subsites will act on more than one HLA at the same time. For example, if the ISA overlap factor is non-zero on only one axis (e.g., OX=1 and OY=0), then each ISA source will act on two different HLA elements. More specifically for this example, for any one HLA site H ij , ISAI must be performed simultaneously ij Encoding, where 1) all subsites have an effect on H ij output, 2) negative n I The subsite acts on its neighbors in the negative X direction, and 3) the positive n I The subsites act on their neighbors in the positive X direction. The encoding process for this example arrangement would require three different coherent light sources and lens sources. Fig.28 The figure shows three planar HLA lenses, taking into account the O X =1 overscan.

[0174] There are many ways to adapt this element, the most straightforward of which is lens multiplication, such as Figure 14-16 As shown, in order to calculate the number of HLA lenses involved in the final ISA subsite encoding region. In addition, this also requires splitting the multiple beams into different optical areas in order to accommodate the CRA required for each lens during the entire encoding process of each n, m subsite.

[0175] Similarly, when there is overlap in two dimensions (OX=1 and OY=1), if these overscan regions are encoded, then up to 9 separate lenses may need to be used simultaneously because each subsite may act on 9 real or virtual HLA subsite locations.

[0176] Design of optical system with only diffractive elements

[0177] Although coded HOEs have certain advantages, optical system designs dictated by single-element or multi-element diffractive optical device array designs are possible.

[0178] Diffractive optical elements (DOEs) have the advantage of utilizing well-established and well-established manufacturing methods. These elements, such as multilayer phased zone plates (PZPs), can be fabricated in thin sheets less than 1 mm thick, and multiple planes of these elements can be used to create lens functions. Fig.29 The illustration in illustrates the ray trajectories of such a design, which contains three diffractive optical elements, where each element and each subsite position has unique diffraction characteristics.

[0179] Additionally, the DOE system can also be manufactured taking into account a virtual HLA, or manufactured with diffractive optics at the ISA plane.

[0180] DOE elements often suffer from a degradation in overall imaging quality due to the large negative chromatic aberration introduced by the DOE element. This can be addressed by implementing the lens function using a hybrid between refractive and diffractive elements. A simple refractive lens can be attached to a thin DOE element so that the large negative chromatic aberration of the DOE is compensated by the positive chromatic aberration of the lens. This hybrid combination can reduce distortion and produce a more uniform point spread function (PSV) across the image plane, thereby improving the off-axis performance of a single simple lens.

[0181] Additional considerations:

[0182] Other options have been considered to reduce the required HOE resolution requirements, including:

[0183] Multiplexing each subsite to form a pattern with different encoding wavelengths similar to the Bayer pattern;

[0184] ● Layering multiple HOEs together to form a more complex optical system from a larger overall holographic pixel; and

[0185] ● Simply temporarily abandon the concept of replicating the lens aperture characteristics and provide independent input reference angles and output object angles for each illuminated pixel, but the resulting visible illumination is significantly reduced.

[0186] Given the limitations of photopolymers, to limit transmission losses, it would be ideal to further divide each subsite into a series of additional N x M subsites (or some larger or smaller value depending on the variables that are multiplexed or removed), each of which exhibits a single, a series of, and / or multiplexed RGB features.

[0187] In the simplest form, each sub-site is divided into N x M "sub-sub-sites", each sub-sub-site having only a single input reference angle and output object angle, which are encoded separately (at the expense of lower visible transmittance, as each sub-site now only exhibits 1 / (N xM) of the total illumination previously envisioned), and are encoded with only a single color (a repeating pattern of RGB with a 1 / 3 loss in angular coding resolution for each sub-site, or some other similar pattern, or multiplexing for RGB), each resulting sub-sub-coding site is now roughly (27.4um / 60x 41.1um / 40).456um x1.0275um.

[0188] Alternative solutions:

[0189] Considering that the input reference angle should ideally be a single beam (compared to N x M), and that a single reference beam may produce complex output angles, it is possible to directly encode the ISA plane with the HLA plate to form a virtual HOE plane.

[0190] If this approach makes sense in some embodiments, additional considerations may be included.

[0191] 1. Through a similar process as suggested above, instead of encoding the input reference directly, we encode the ISA coordinates directly.

[0192] 2. Each ISA site can produce a near-collimated illumination source even though the illumination source is not naturally collimated, with simple diffractive elements (e.g., phase-knifing, etc.) and / or pinhole mask arrays, and / or with the HOE placed directly on the ISA surface as close to the illumination plane as possible using appropriate refractive matching adhesives and / or materials. All of the above discussion can also be discussed in this regard.

[0193] 3. Now that the input reference beam comes from a single angle (ideally perpendicular to the normal to the HOE surface, or another direction compensated by the diffractive optical element), the object beam utilizes a series of optical elements to expand and focus the beam to the same ISA coordinates as the reference beam.

[0194] 4. Form the object beam to match:

[0195] a. Size of the HLA optical element wxh at a virtual distance f from the ISA coding site

[0196] b. Tilt appropriately so that the CRA passes through rays that intersect the virtual HLA center and the ISA encoded coordinates respectively

[0197] c. The appropriate aperture and focal length are considered so that the light rays focused at the ISA appropriately match the diagram provided above.

[0198] d. When considered a reflection (or another) hologram.

[0199] Note: The ISA wxh may now need to match the HLA, or the HLA may be larger (much larger) in the virtual coordinate system. This may not be a problem, and the specified ISA overlap region may have multiple encoding angles that may be offset by some amount, or greater than 10°.

[0200] Alternatively, by masking portions of the object beam, each ISA subsite is encoded with partial coverage per exposure, so that a "pie-shaped" segment from the entire beam is focused only at the HOE and provides a portion of the total lens. In the current embodiment, there is a 200% overlap between the HLA and ISA, respectively, allowing each ISA coordinate to have up to four shared HLAs. This results in one-quarter of the interference pattern being exposed to maintain this relationship, which is possible using this approach or some combination of segmentation and multiplexing.

[0201] Since all light passes through the HLA coordinate system (when viewed as a transmission / stereo or similar replicating hologram), the challenge may be that the light is no longer collimated by the reference beam and the coded pattern of the associated diffracted object beam as originally envisioned, and the light from the illumination source will pass through the virtual HLA plane and continue to move in space without further changing angles as needed to properly observe each HLA subsite. Depending on the ideal viewing distance and subsite FOV, this may or may not be a big problem (currently believed to be detrimental to viewable image quality).

[0202] However, adding a second (or more) HOEs at or near the location of the virtual HLA plane can encode corrective action for rays passing through each of these virtual HLA subsite coordinates.

[0203] Each coordinate at the virtual HLA now has a convergent portion of the rays from all ISA subsites. It is now possible to design the addition of diffraction elements (e.g., kinematics, gratings, Fresnel arrays, etc.) to correct the CRA from each HLA subsite, where the central ray from the ISA ray bundle set can be calculated and corrected to meet the desired HLA specification.

[0204] In this way, it is also possible to form simple digital holographic pixels to perform this correction using the same method explained above, where the CRA from the object beam (now with its position reversed from the previous reference beam) is formed to match the required correction factors so that the incorrectly divergent light is diffracted into the correct orientation by changing the focus, aperture, position and rotation angle according to the most ideal configuration given the reference beam.

[0205] Other methods are contemplated in this disclosure:

[0206] ● Encode the master HOE as an edge-lit hologram and include this illumination source as an element in the final display throughout the replication process

[0207] ● Convert the master from reflection / stereo / transmission to transmission / reflection / stereo holograms by offsetting the replica plane from the HLA position (or original placement, depending on the configuration implemented) to the ISA plane (or alternative plane) to convert between the master and various replicas

[0208] ●Converting an original or replica from a reflection / stereo / transmission hologram to a reflection or transmission edge-lit hologram to enable observation of the encoded optical properties using a laser illumination source optimized and controlled based on the encoding process, providing higher quality HOE without the use of white light.

[0209] Although various embodiments according to the principles disclosed herein have been described above, it should be understood that they are presented by way of example only and are not limiting. Therefore, the breadth and scope of the present disclosure should not be limited by any of the exemplary embodiments described above, but should only be defined in accordance with the claims issued by the present disclosure and their equivalents. In addition, the above advantages and features are provided in the described embodiments, and the application of such issued claims should not be limited to the process and structure that realize any or all of the above advantages.

[0210] It should be understood that the main features of the present disclosure may be employed in various embodiments without departing from the scope of the present disclosure. Those skilled in the art will recognize or be able to determine many equivalents to the specific methods described herein using no more than routine experiments. Such equivalents are considered to be within the scope of the present disclosure and are covered by the claims.

[0211] In addition, the section titles herein are provided for consistency with the recommendations of 37CFR 1.77, or otherwise provide organizational cues. These titles should not limit or characterize the inventions set forth in any claims that may be issued from this disclosure. Specifically and as an example, although the title mentions the "technical field", such claims should not be limited by the language describing the so-called technical field under this title. In addition, the description of the technology in the "background technology" section should not be understood as an admission that the technology is the prior art of any invention in this disclosure. "Summary of the invention" should also not be considered as a feature of the invention set forth in the issued claims. In addition, any reference to "invention" in the singular form in this disclosure should not be used to argue that there is only a single novel point in this disclosure. Multiple inventions may be set forth according to the limitations of multiple claims issued from this disclosure, and such claims accordingly define the inventions and their equivalents protected thereby. In all cases, the scope of such claims should be considered on their own merits in view of this disclosure, and should not be constrained by the titles set forth herein.

[0212] The word "a" when used in conjunction with the term "comprising" in the claims and / or specification may refer to "one", and it also complies with the meaning of "one or more", "at least one" and "one or more than one". Although the present disclosure supports reference to individual alternatives and the definition of "and / or", unless it is explicitly indicated that individual alternatives are referred to or the alternatives are mutually exclusive, the term "or" used in the claims is used to refer to "and / or". Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error of the device, method used to determine the value, or the variation that exists between research subjects. In general but consistent with the foregoing discussion, the numerical values ​​modified by approximate terms such as "about" herein may vary by at least ±1, 2, 3, 4, 5, 6, 7, 10, 12 or 15% from the stated value.

[0213] As used in this specification and claims, the words "comprise" (and any form of comprising, such as "comprises" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include"), or "contain" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended, and do not exclude additional unrecited elements or method steps.

[0214] Comparison, measurement, and timing terms such as "at," "equivalent to," "during," "completely," and the like should be understood to mean "substantially at," "substantially equivalent to," "substantially during," "substantially completely," and the like, where "substantially" means that such comparisons, measurements, and timing can be used to achieve the desired results either implicitly or explicitly stated. Terms such as "near," "close to," and "adjacent," relating to the relative position of elements, should mean close enough to have a substantial effect on the interaction of the corresponding system elements. Other approximate terms similarly refer to certain conditions that, when so modified, are understood not to be necessarily absolute or perfect, but would be considered close enough to warrant the existence of the specified conditions by one skilled in the art. The degree to which the description can vary will depend on how large a variation can be made and still allow one of ordinary skill in the art to recognize the modified feature as still having the desired properties and capabilities of the unmodified feature.

[0215] As used herein, the term "or combinations thereof" refers to all permutations and combinations of the listed items preceding the term. For example, A, B, C, or combinations thereof are intended to include at least one of A, B, C, AB, AC, BC, or ABC, and if order is important in a particular case, BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, combinations containing repetitions of one or more items or clauses are expressly included, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, etc. Those skilled in the art will appreciate that, unless otherwise apparent from the context, there is generally no limit to the number of items or clauses in any combination.

[0216] All compositions and / or methods disclosed and claimed herein can be made and performed without undue experimentation in accordance with the present disclosure. Although the compositions and methods of the present disclosure have been described in terms of preferred embodiments, it is apparent to those skilled in the art that changes may be made to the compositions and / or methods and in the steps or sequence of steps of the methods described herein without departing from the concept, spirit and scope of the present disclosure. All such similar substitutions and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the present disclosure as defined by the appended claims.

Claims

1. A waveguide comprising a substrate comprising a photographic medium; and an interference pattern encoded in said photographic medium, said interference pattern defining an array of substrate sites in said substrate; wherein the interference pattern is configured to propagate light along a light propagation path extending from a light location on a first side of the substrate toward a second side of the substrate; wherein the light propagation paths include a plurality of groups of light propagation paths extending through a same substrate site and a same light position, wherein each group of light propagation paths is configured to extend substantially in a unique direction on the second side of the substrate and converge from the same substrate site to the same light position on the first side of the substrate, the unique direction being determined by the angular directions of the principal ray propagation paths in each group of light propagation paths; Thereby, the array of substrate sites is configured to propagate light according to a four-dimensional light field coordinate system comprising spatial coordinates defined by the positions of the substrate sites and angular coordinates defined by the unique directions of the multiple sets of light propagation paths for each substrate site.

2. The waveguide of claim 1, wherein the photographic medium comprises at least one material selected from the group consisting of: photographic emulsion, dichromated gelatin, photoresist, photothermoplastic, photopolymer, and photorefractive material.

3. The waveguide of claim 1, wherein the interference pattern comprises a hologram encoded to guide light as a microlens array, thereby forming a holographic microlens array ("HLA").

4. The waveguide of claim 3, wherein the hologram comprises a reflection hologram.

5. The waveguide of claim 3, wherein the hologram comprises a transmission hologram.

6. The waveguide of claim 3, wherein the HLA comprises a plane subdivided into sites, and the substrate sites correspond to the sites of the HLA.

7. The waveguide of claim 6, wherein the sites of the HLAs are each configured to guide light as a microlens.

8. A holographic energy guiding system comprising a waveguide according to claim 1 and an illumination source array ("ISA") configured to provide illumination at the light locations on the first side of the substrate.

9. The holographic energy guiding system of claim 8, wherein the ISA comprises a plurality of light sources at the light locations on the first side of the substrate.

10. A holographic energy guiding system according to claim 8, wherein the ISA defines a plane subdivided into sites, and the sites of the ISA respectively correspond to at least one corresponding site of the HLA, and respectively include multiple ISA sub-site positions corresponding to the light positions on the first side of the substrate.

Images