Holographic projector including size correction and alignment of light beams with different light wavelengths

Abstract

The holographic projection system includes a first, second and third light source, an SLM, a lens, a combiner and a control module. The first, second and third light sources generate corresponding light beams. The light beams have corresponding wavelengths. The SLMs diffract the light beams respectively. The lens is configured to adjust the divergence angle of one of the light beams so that the diffracted light leaving each of the SLMs is at the same diffraction angle. The SLM encodes a phase hologram including a corresponding version of a graphic image based on the light generated by the light source, including the light output from the lens, to provide a phase hologram beam. The combiner combines the phase hologram beams to provide a combined phase hologram beam, which is projected for viewing the combined graphic image. The control module encodes a prismatic hologram on one of the SLMs to align the output of the SLM.

Description

Technical Field

[0001] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. To the extent described in this section, the work of the presently named inventors and aspects of this specification that may not otherwise be recognized as prior art at the time of filing are neither explicitly nor implicitly admitted as prior art with respect to the present disclosure.

[0002] The present disclosure relates to a projection holographic display system and a head-up display system of a vehicle. Background Art

[0003] Display devices are used in a variety of applications. Some exemplary display devices are flat panel displays, projection displays, and heads-up displays. Display devices can be transmissive or reflective.

[0004] Traditionally, the driver of a vehicle views the surroundings of the vehicle through windows, windshields, and other glass of the vehicle. The driver can control the acceleration, deceleration, and steering of the vehicle based on the driver's visual observation of the surroundings of the vehicle. The vehicle may include one or more displays that display various information to the driver. For example, some vehicles include an infotainment system that includes a display that displays various infotainment and other vehicle information. The vehicle may also include a head-up display (HUD) that displays information by forming a virtual image at a distance using reflections from the windshield. For example, the HUD may display vehicle speed and other vehicle information (e.g., warnings, such as lane departure warnings and collision avoidance warnings). Summary of the invention

[0005] The holographic projection system includes a first light source, a second light source, a third light source, a spatial light modulator, a first lens, a combiner, and a control module. The first light source is configured to generate a first light beam. The second light source is configured to generate a second light beam. The third light source is configured to generate a third light beam. The first light beam, the second light beam, and the third light beam have corresponding wavelengths. The spatial light modulator is configured to diffract the first light beam, the second light beam, and the third light beam, respectively. The first lens is configured to adjust the divergence angle of one of the first light beam, the second light beam, or the third light beam so that the diffracted light leaving each of the spatial light modulators is at the same diffraction angle. The spatial light modulator is configured to encode a phase hologram including a corresponding version of a graphic image based on the light generated by the first light source, the second light source, and the third light source, including the light output from the first lens, to provide a phase hologram beam. The combiner is configured to combine the phase hologram beams to provide a combined phase hologram beam, which is projected for viewing the combined graphic image. The control module is configured to encode a prismatic hologram on one of the spatial light modulators to align an output of the spatial light modulator.

[0006] In other features, the first light beam is a red laser beam. The second light beam is a green laser beam. The third light beam is a blue laser beam.

[0007] In other features, the holographic projection system further includes a second lens. The first lens adjusts the divergence angle of the green laser beam to match the divergence angle of the red laser beam diffracted by one of the spatial light modulators. The second lens adjusts the divergence angle of the blue laser beam to match the divergence angle of the red laser beam diffracted by one of the spatial light modulators.

[0008] In other features, the first lens adjusts the divergence angle of the red laser beam to match the divergence angle of the green laser beam diffracted by one of the spatial light modulators.

[0009] Among other features, the holographic projection system lacks a lens for adjusting the divergence angle of the blue laser beam.

[0010] In other features, one or more of the spatial light modulators includes a non-periodic photon sieve layer to adjust a divergence angle of one or more of the first light beam, the second light beam, and the third light beam.

[0011] In other features, the control module is configured to encode a lens hologram on one or more of the spatial light modulators to adjust a size of one or more of the first light beam, the second light beam, and the third light beam.

[0012] In other features, the control module is configured to encode two prismatic holograms on two of the spatial light modulators, respectively, to shift positions of two of the first light beam, the second light beam, and the third light beam.

[0013] In other features, the control module is configured to size the first beam, the second beam, and the third beam to not fill an available image area, and to adjust a position of one or more of the first beam, the second beam, and the third beam to align the first beam, the second beam, and the third beam.

[0014] In other features, a holographic projection system is provided, and the holographic projection system includes a first light source, a second light source, a third light source, a spatial light modulator, a combiner, and a control module. The first light source is configured to generate a first light beam. The second light source is configured to generate a second light beam. The third light source is configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths. The spatial light modulator is configured to encode a phase hologram including a corresponding version of a graphic image based on the light generated by the first light source, the second light source, and the third light source to provide a phase hologram beam. The first of the spatial light modulators includes a first non-periodic photon sieve layer. The first non-periodic photon sieve layer is configured to adjust the divergence angle of one of the first light beam, the second light beam, or the third light beam so that the diffracted light leaving each of the spatial light modulators is at the same diffraction angle. The combiner is configured to combine the phase hologram beams to provide a combined phase hologram beam, which is projected for viewing the combined graphic image. The control module is configured to encode a prismatic hologram on one of the spatial light modulators to align an output of the spatial light modulator.

[0015] In other features, the first of the spatial light modulators that includes the first non-periodic photon sieve layer is the same spatial light modulator for which the control module encodes the prismatic hologram.

[0016] In other features, a first one of the spatial light modulators that includes a first non-periodic photon sieve layer is a different spatial light modulator for which the control module encodes a prismatic hologram.

[0017] In other features, the first light beam is a red laser beam. The second light beam is a green laser beam. The third light beam is a blue laser beam.

[0018] In other features, a first of the spatial light modulators receives a green laser beam. A second of the spatial light modulators receives a blue laser beam and includes a second non-periodic photon sieve layer. The first non-periodic photon sieve layer adjusts the divergence angle of the green laser beam to match the divergence angle of the red laser beam diffracted by the third of the spatial light modulators. The second non-periodic photon sieve layer adjusts the divergence angle of the blue laser beam to match the divergence angle of the red laser beam diffracted by the third of the spatial light modulators.

[0019] In other features, the first non-periodic photon sieve layer adjusts the divergence angle of the red laser beam to match the divergence angle of the green laser beam diffracted by the first one of the spatial light modulators.

[0020] Among other features, the holographic projection system lacks a non-periodic photon sieve layer for adjusting the divergence angle of the blue laser beam.

[0021] In other features, a holographic projection system is provided, and the holographic projection system includes a first light source, a second light source, a third light source, a spatial light modulator, and a control module. The first light source is configured to generate a first light beam. The second light source is configured to generate a second light beam. The third light source is configured to generate a third light beam. The first light beam, the second light beam, and the third light beam have corresponding wavelengths. The spatial light modulator is configured to encode a phase hologram including a graphic image, and the graphic image is generated based on a combination of light from the first light beam, the second light beam, and the third light beam. The control module is configured to: encode one or more lens holograms on the first or more of the spatial light modulators to adjust the size of another of the first light beam, the second light beam, or the third light beam relative to one of the first light beam, the second light beam, or the third light beam; and encode one or more prism holograms on the second or more of the spatial light modulators to align the first light beam, the second light beam, and the third light beam.

[0022] In other features, the holographic projection system further includes a combiner for: combining the outputs of three of the spatial light modulators to provide a combined phase hologram beam, which is projected for viewing a combined graphic image; or combining the outputs of the first light source, the second light source, and the third light source before the first light beam, the second light beam, and the third light beam are received at the spatial light modulator.

[0023] In other features, the spatial light modulator includes: a first spatial light modulator; and a second spatial light modulator downstream of the first spatial light modulator. The control module is configured to: encode at least one of a lens hologram or a prismatic hologram on the first spatial light modulator; and encode a graphic image on the second spatial light modulator.

[0024] In other features, the spatial light modulator includes: a third spatial light modulator; and a fourth spatial light modulator downstream of the first spatial light modulator. The first spatial light modulator receives the first light beam. The third spatial light modulator receives the second light beam. The control module is configured to: encode at least one of a lens hologram or a prismatic hologram on the third spatial light modulator; and encode a graphic image on the second spatial light modulator and the fourth spatial light modulator.

[0025] The present disclosure also proposes the following technical solutions.

[0026] 1. Holographic projection system, including:

[0027] a first light source configured to generate a first light beam;

[0028] a second light source configured to generate a second light beam;

[0029] a third light source configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths;

[0030] a plurality of spatial light modulators configured to diffract the first light beam, the second light beam, and the third light beam, respectively;

[0031] a first lens configured to adjust a divergence angle of one of the first light beam, the second light beam, or the third light beam so that diffracted light exiting from each of the plurality of spatial light modulators is at the same diffraction angle,

[0032] wherein the plurality of spatial light modulators are configured to encode a phase hologram including a corresponding version of a graphic image based on light generated by the first light source, the second light source, and the third light source, including light output from the first lens, to provide a phase hologram light beam;

[0033] a combiner configured to combine the phase hologram beams to provide a combined phase hologram beam, the combined phase hologram beam being projected for viewing a combined graphic image; and

[0034] A control module is configured to encode a prismatic hologram on one of the plurality of spatial light modulators to align outputs of the plurality of spatial light modulators.

[0035] 2. The holographic projection system according to technical solution 1, wherein:

[0036] The first light beam is a red laser beam;

[0037] The second light beam is a green laser light beam; and

[0038] The third light beam is a blue laser light beam.

[0039] 3. The holographic projection system according to technical solution 2 further comprises a second lens, wherein:

[0040] The first lens adjusts a divergence angle of the green laser beam to match a divergence angle of the red laser beam diffracted by one of the plurality of spatial light modulators; and

[0041] The second lens adjusts a divergence angle of the blue laser beam to match a divergence angle of the red laser beam diffracted by one of the plurality of spatial light modulators.

[0042] 4. A holographic projection system according to technical solution 2, wherein the first lens adjusts the divergence angle of the red laser beam to match the divergence angle of the green laser beam diffracted by one of the multiple spatial light modulators.

[0043] 5. The holographic projection system according to Technical Solution 4, wherein the holographic projection system lacks a lens for adjusting the divergence angle of the blue laser light beam.

[0044] 6. A holographic projection system according to technical solution 1, wherein one or more of the multiple spatial light modulators includes a non-periodic photon sieve layer to adjust the divergence angle of one or more of the first light beam, the second light beam and the third light beam.

[0045] 7. A holographic projection system according to technical solution 1, wherein the control module is configured to encode a lens hologram on one or more of the multiple spatial light modulators to adjust the size of one or more of the first light beam, the second light beam, and the third light beam.

[0046] 8. A holographic projection system according to technical solution 1, wherein the control module is configured to encode two prismatic holograms on two of the multiple spatial light modulators, respectively, to shift the positions of two of the first light beam, the second light beam, and the third light beam.

[0047] 9. A holographic projection system according to technical solution 1, wherein the control module is configured to size the first beam, the second beam, and the third beam so as not to fill the available image area, and adjust the position of one or more of the first beam, the second beam, and the third beam to align the first beam, the second beam, and the third beam.

[0048] 10. Holographic projection system, including:

[0049] a first light source configured to generate a first light beam;

[0050] a second light source configured to generate a second light beam;

[0051] a third light source configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths;

[0052] a plurality of spatial light modulators configured to encode a phase hologram including a corresponding version of a graphic image based on light generated by the first light source, the second light source, and the third light source to provide a phase hologram light beam, wherein a first one of the spatial light modulators includes a first non-periodic photon sieve layer, and wherein the first non-periodic photon sieve layer is configured to adjust a divergence angle of one of the first light beam, the second light beam, or the third light beam so that diffracted light exiting from each of the plurality of spatial light modulators is at a same diffraction angle;

[0053] a combiner configured to combine the phase hologram beams to provide a combined phase hologram beam, the combined phase hologram beam being projected for viewing a combined graphic image; and

[0054] A control module is configured to encode a prismatic hologram on one of the plurality of spatial light modulators to align outputs of the plurality of spatial light modulators.

[0055] 11. A holographic projection system according to technical solution 10, wherein the first of the multiple spatial light modulators that includes the first non-periodic photon sieve layer is the same spatial light modulator for which the control module encodes the prismatic hologram.

[0056] 12. A holographic projection system according to technical solution 10, wherein the first one of the multiple spatial light modulators that includes the first non-periodic photon sieve layer is a different spatial light modulator for which the control module encodes the prism hologram.

[0057] 13. The holographic projection system according to technical solution 10, wherein:

[0058] The first light beam is a red laser beam;

[0059] The second light beam is a green laser light beam; and

[0060] The third light beam is a blue laser light beam.

[0061] 14. The holographic projection system according to technical solution 13, wherein:

[0062] The first one of the plurality of spatial light modulators receives the green laser beam;

[0063] A second one of the plurality of spatial light modulators receives the blue laser beam and includes a second non-periodic photon sieve layer;

[0064] The first non-periodic photon sieve layer adjusts a divergence angle of the green laser beam to match a divergence angle of the red laser beam diffracted by a third of the plurality of spatial light modulators; and

[0065] The second non-periodic photon sieve layer adjusts a divergence angle of the blue laser beam to match a divergence angle of the red laser beam diffracted by the third of the plurality of spatial light modulators.

[0066] 15. A holographic projection system according to technical solution 13, wherein the first non-periodic photon sieve layer adjusts the divergence angle of the red laser beam to match the divergence angle of the green laser beam diffracted by the first one of the multiple spatial light modulators.

[0067] 16. A holographic projection system according to technical solution 15, wherein the holographic projection system lacks a non-periodic photon sieve layer for adjusting the divergence angle of the blue laser light beam.

[0068] 17. Holographic projection system, including:

[0069] a first light source configured to generate a first light beam;

[0070] a second light source configured to generate a second light beam;

[0071] a third light source configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths;

[0072] a plurality of spatial light modulators configured to encode a phase hologram comprising a graphical image generated based on a combination of light from the first light beam, the second light beam, and the third light beam; and

[0073] The control module is configured as

[0074] encoding one or more lens holograms on a first one or more of the plurality of spatial light modulators to adjust a size of another of the first, second, or third light beams relative to one of the first, second, or third light beams, and

[0075] One or more prismatic holograms are encoded on a second one or more of the plurality of spatial light modulators to align the first light beam, the second light beam, and the third light beam.

[0076] 18. The holographic projection system according to technical solution 17 further comprises a combiner for:

[0077] combining the outputs of three of the plurality of spatial light modulators to provide a combined phase hologram beam, the combined phase hologram beam being projected for viewing a combined graphic image; or

[0078] The outputs of the first, second, and third light sources are combined before the first, second, and third light beams are received at the plurality of spatial light modulators.

[0079] 19. The holographic projection system according to technical solution 17, wherein the plurality of spatial light modulators include:

[0080] a first spatial light modulator; and

[0081] a second spatial light modulator, downstream of said first spatial light modulator,

[0082] Wherein, the control module is configured as

[0083] encoding at least one of a lens hologram or a prismatic hologram on the first spatial light modulator, and

[0084] The graphical image is encoded on the second spatial light modulator.

[0085] 20. The holographic projection system according to technical solution 19, wherein the plurality of spatial light modulators include:

[0086] a third spatial light modulator; and

[0087] a fourth spatial light modulator, downstream of the first spatial light modulator,

[0088] in,

[0089] The first spatial light modulator receives the first light beam,

[0090] The third spatial light modulator receives the second light beam, and

[0091] The control module is configured to

[0092] encoding at least one of a lens hologram or a prismatic hologram on the third spatial light modulator, and

[0093] The graphical image is encoded on the second spatial light modulator and the fourth spatial light modulator.

[0094] Other areas of applicability of the present disclosure will become apparent from the detailed description, claims and drawings.The detailed description and specific examples are intended for illustrative purposes only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0095] The present disclosure will become more fully understood based on the detailed description and accompanying drawings, in which:

[0096] Figure 1 is an exemplary diagram showing diffraction angles for a spatial light modulator (SLM);

[0097] Figure 2 is a graph of exemplary intensity versus diffraction angle showing the difference in diffraction angle for red light and blue light;

[0098] Figure 3 is an exemplary bar graph showing differences in alignment and size of blue, green, and red light beams due to different diffraction angles;

[0099] Figure 4is an exemplary diagram showing misalignment of different red, green and blue (RGB) images due to a difference in diffraction angles and the resulting images after correcting the misalignment according to the present disclosure;

[0100] Figure 5 is a functional block diagram of an example of a holographic projection system including an RGB SLM and an X-cube combiner according to the present disclosure;

[0101] Fig. 6A is a side view of a red laser and SLM showing laser divergence of red light according to the present disclosure;

[0102] Figure 6B is a side view of a green laser, lens, and SLM showing laser divergence of green light according to the present disclosure;

[0103] Figure 6C is a side view of a blue laser, lens, and SLM showing laser divergence of blue light according to the present disclosure;

[0104] Fig. 7A is an exemplary diagram showing diffraction angle and viewing area size without using a non-periodic photon sieve;

[0105] Figure 7B is an exemplary diagram showing diffraction angle and viewing area size when using a non-periodic photon sieve according to the present disclosure;

[0106] Figure 8 is an exemplary hologram showing the introduction of prism and lens holograms for position and size adjustment of RGB images via software and SLM(s) according to the present disclosure;

[0107] Fig. 9 is a functional block diagram of an example of a holographic projection system incorporating dual SLMs and introducing prism and lens holograms and focal plane distance compensation according to the present disclosure;

[0108] Fig.10 is a perspective view of an exemplary interior of a vehicle including a HUD;

[0109] Fig.11 yes Fig. 9 A functional block diagram of an exemplary embodiment of a holographic projection system;

[0110] Fig.12 An exemplary holographic projection method according to the present disclosure is shown;

[0111] Fig.13 is a cross-sectional view of an example of a liquid crystal on silicon (LCoS) SLM according to the present disclosure; and

[0112] Fig.14is a functional block diagram of an example of parts and control modules of an LCoS SLM according to the present disclosure.

[0113] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0114] A vehicle may include a holographic HUD that includes an SLM and a coherent or partially coherent light source. A phase hologram is encoded on the SLM. Light from the coherent or partially coherent light source illuminates the SLM encoded with the phase hologram, and the light is diffracted in a manner specified by the hologram. The diffracted light is reflected by the vehicle's windshield and forms a real image on the driver's retina.

[0115] Holographic display systems typically employ a coherent light source (e.g., laser) in conjunction with other display components. Coherent light may refer to light that is in phase in space and time. When coherent light reflects from a surface, each point on the surface is seen as a secondary light wave. When separate RGB channels are used, such as in a 3-LCoS holographic HUD, it is necessary to provide three spatially aligned RGB images at the eye box, otherwise the viewer will see three misaligned images. The eye box may refer to a rectangular planar area in which the viewer is able to see the image.

[0116] Figure 1 and Figure 2 A graph showing the diffraction angle θ for the SLM 100 and a graph of intensity versus diffraction angle curves 206, 208 for red and blue light, respectively, for the SLM 100 are shown. As shown, an incident light beam 102 is directed at the SLM 100 and reflected from the SLM 100. The reflection of the incident light beam 102 provides: (i) a central maximum at a peak of 0 along the central axis; and (ii) an additional reduction in the maximum size symmetrically about the central axis of the central maximum in the order of diffraction. The maximum can be represented by Equation 1, where Λ is the pitch of the SLM 100, m is an integer, and λ is the wavelength of light. The pitch Λ refers to the distance between the grooves 110 of the SLM 100:

[0117] Λsinθ = mλ

[0118] The resulting diffracted light distribution for different wavelengths RGB depends on the diffraction angle according to the wavelength at the SLM 100 and the misalignment of the optical components of the corresponding holographic projection system. The misalignment of the optical components may refer to the misalignment of any optical component of the holographic projection system. The misalignment may be due to, for example, the windshield angle, the lens angle, the angle and / or position of the SLM, the angle of the beam expander, etc. The different reflection spectra of the light associated with the first (-1 and 1) maximum are represented by the "pie" shapes 112, 114. The intensity modulation is Figure 22 is represented by dashed curves 216, 218 for red and blue light respectively. A first minimum 220, 222 is shown between the central maximum and the first maximum.

[0119] The size and position of the image in a holographic display varies with wavelength. Figure 3 and Figure 4 Shown in. Figure 3 A bar graph is shown showing the differences in alignment and size of blue, green, and red light due to the different diffraction angles of the respective colored light beams. For example, first strips 300a, 300b, 302a, 302b, 304a, 304b of respective blue, green, and red light are shown with different positions relative to the central axis 310 and different widths (or sizes). Figure 4 Shown are: (i) the misalignment of the red image 400, the green image 402, and the blue image 404 due to differences in the respective diffraction angles; and (ii) the resulting image 410 after the misalignment is corrected using the techniques disclosed herein. The resulting image 410 may be a white image provided by combining the RGB images 400, 402, 404 of the same size.

[0120] In a holographic display system, alignment of the three primary color picture generating units is challenging. Misalignment can be: (i) due to different diffraction angles of light beams of different colors reflected from the corresponding SLMs; (ii) due to misalignment of the optical components of the corresponding holographic imaging system; and / or (iii) caused by a diffractive optical expander. Misalignment due to optical components can involve the SLM, the distance between the light beams leaving the SLM and the optical expander, and the distance between the optical expander and the viewer's eyes.

[0121] In addition, the picture generation hardware of the holographic imaging system controls the diffraction of light, which is based on wavelength. The projected image size is proportional to the diffraction angle of the light of the projected image. The diffraction angle is directly related to the wavelength of the light. If the hologram is illuminated with different wavelengths, a single output image will be seen as three images of different sizes and different positions. As the distance between the picture generation hardware and the viewer's eyes increases, the misalignment and size differences of different color images can become more obvious to the viewer. For near-eye displays (e.g., those in virtual reality or augmented reality head-mounted machines) where the image is projected near the viewer's eyes, the color misalignment problem is minimal. For example, in a vehicle, in the case of a HUD, when the holographic system optics are scaled and projected at a large distance before the hologram reaches the viewer's eyes, the problem of misalignment and size differences for different colors is aggravated. Moreover, in different vehicles, the distance between the picture generation hardware and the viewer's eyes is different.

[0122] Examples disclosed herein correct for and account for color misalignment and image size differences. Examples include a projection holographic display system that adjusts the size and position of RGB images to provide overlapping images of the same size. When the size of a monochromatic light beam is adjusted, the divergence angle and / or cross-sectional area of ​​the light beam intercepted perpendicular to the emission direction of the light beam (or the path of the light beam) is adjusted. When the position of the monochromatic image, and therefore the position of the corresponding light beam, is adjusted, the vertical and / or horizontal position relative to the eye box is adjusted. For example, the image may be moved vertically or horizontally in the image plane at the viewer's eye. The RGB images are aligned so that the images have the same overlapping center point and are aligned vertically and horizontally to provide a single image in which none of the images overhangs any other image. This example is in Figure 4 4. Therein, images 400, 402, 404 have respective center points 412, 414, 416 that overlap, as indicated by point 418.

[0123] Several different examples are provided for eliminating color misalignment. Some of them include diffraction angle matching for image resizing and software prism encoding for spatial alignment. As an example, one of the holographic display systems uses an RGB LCoS SLM to adjust the RGB laser divergence to compensate for the diffraction angle differences to form RGB images of the same size using a solid lens, an electrically tunable lens and / or an SLM with a pinhole layer. Then, one or more prism function holograms are used to adjust the alignment of one or more of the RGB images so that the RGB images are aligned relative to each other at the eye box. The example allows for accounting for varying virtual image distances to maintain alignment of different color images.

[0124] Figure 5 An example of a holographic projection system 500 is shown, which includes a control module 502, a red light source 504, a green light source 506, a blue light source 508, an RGB SLM 510, 512, 514, an X-cube combiner 516, and an optical expander 518. The light sources 502, 504, 506 may be lasers or other suitable light sources. In one embodiment, the RGB SLM 510, 512, 514 is implemented as an LCoS SLM. The light beams generated by the light sources 502, 504, 506 are provided to the RGB SLM 510, 512, 514.

[0125] During operation, the RGB SLMs 510, 512, 514 receive control signals from the control module 502, which provides a phase hologram of the pattern to be projected. The phase hologram beams 520, 522, 524 exiting the RGB SLMs 510, 512, 514 are the product of the wavefront of the pattern to be projected in the frequency domain and the phase hologram. The outputs of the RGB SLMs 510, 512, 514 are combined by an X-cube combiner 516. The output of the X-cube combiner 516 is provided to an optical expander 518, which expands the beam received from the X-cube combiner 516 (before being reflected from the windshield 530 and received at the viewer's retina 532). The viewer perceives an image 534 of an object in front of the windshield 530.

[0126] Can Figure 5 The example is modified to include the following relative to Figure 6A-Figure 8 The features described and / or other disclosed features may be Figure 5 The example is modified to include Figure 6A-Figure 8 More than one feature and / or other disclosed features.

[0127] As a first example, Figure 6A-6C (collectively FIG. 6 ) shows a red light source 600, a green light source 602, and a blue light source 604, lenses 606, 608, and SLMs 610, 612, 614. The light sources 600, 602, 604, and the SLMs 610, 612, 614 may represent Figure 5 In one embodiment, the light sources 504, 506, 508 and the RGB SLMs 510, 512, 514 are Figure 5 The system 500 is modified to include lenses 606, 608. The system 500 can be modified to include one or more lenses for corresponding one or more of the light sources 504 (or 600), 506 (or 602), 508 (or 604).

[0128] Provided Figure 6A-6C As an example of an implementation, the diffraction angle of the light beam is adjusted to provide the resulting light beams 620, 622, 624 having the same size. Fig. 6A An example of red light divergence is shown. Figure 6B An example of green light divergence is shown. Figure 6C An example of blue light divergence is shown. As used herein, the term divergence refers to the divergence of a beam, which is an angular measure of the increase in beam diameter or radius with distance. Although lenses 606, 608 are shown for green and blue beams, lenses may be included for any of the red, green, and blue beams. The lenses may be solid fixed lenses or electrically tunable lenses. If electrically tunable, then Figure 5The control module 502 can be connected to the lens and control the state of the lens. Figure 6B and Figure 6C As shown in , a lens may be disposed between the light source and the corresponding SLM. The lens is included and / or controlled to tune the beam divergence and therefore the beam size. The lens changes the divergence of the received light beam. In the example shown, lenses are provided for the green and blue light sources to further diverge the output of the light sources to match the divergence of the red light. In this example, to maximize the field of view, the longest of the three wavelengths of the RGB light is red and is designated as the baseline (or reference), and a compensating component (e.g., a lens as described above and / or an SLM with a pinhole layer and / or a lens hologram as described below) is applied to the green and blue light beams.

[0129] In another embodiment, to minimize the number of compensating components, the center wavelength (green) is selected as the baseline (or reference). Blue is not compensated because the diffraction angle of blue is close to the diffraction angle of green. Compensating components (e.g., a lens as described above and / or an SLM with a pinhole layer and / or a lens hologram as described below) are applied to red. In an embodiment, a control module (e.g., one of the control modules disclosed herein) selects the color light source (or wavelength) that is actually used as the baseline, and then adjusts the divergence angle of one or more of the other light sources.

[0130] As an alternative or in addition to using a lens, one or more of the SLMs 610, 612, 614 may include a pinhole layer (or a non-periodic photon sieve) comprising "pin" holes for broadening the diffraction of light passing through the SLM. Fig. 7A and Figure 7B Shown. Fig. 7A The diffraction angle φ1 of SLM 700 and the corresponding viewing area size at observation plane 702 are shown. SLM 700 does not include a non-periodic photon sieve (or pinhole layer). Figure 7B The diffraction angle φ2 of the SLM 710 and the corresponding viewing area size at the observation plane 711 are shown in the case of using a non-periodic photon sieve (or pinhole layer) 712. The pinhole layer 712 is disposed on a substrate 714 and includes pinholes 716 for passing light. Figure 7B The dotted lines 720, 722 and Fig. 7A The solid lines 724, 726 correspond (match) and are provided to illustrate the difference in the divergence and viewing area sizes. Fig. 7A and Figure 7B The focal points of the example are indicated as z1 and z2. Pinhole 716 allows light to pass through and diffracts light. The rest of the pinhole layer 712 is absorptive and prevents the passage of light. Pinhole 716 changes the divergence of the received light.

[0131] Figure 8 The introduction of a prismatic hologram 800 and a lenticular hologram 802 via software and one or more SLMs is shown for position and size adjustment of the RGB image, respectively. Figure 8 Examples may be used as alternatives and / or in conjunction with those described herein, including those described above with respect to Figure 5-7B The control module 502 may encode a prismatic hologram and / or a lens hologram on one or more of the SLMs 510, 512, 514, 610, 612, and 614. This may be in addition to a graphic hologram (e.g., graphic holograms 804, 806), which may also be encoded on one or more of the SLMs 510, 512, 514, 610, 612, and 614 via the control module 502. Prismatic holograms cause corresponding images to shift upward, downward, left, and / or right. Lens holograms change the size of the image. As shown, prismatic holograms and lens holograms are actually multiplied with the graphic hologram to provide the resulting image. Different prism and lens functions may be included to remove and / or compensate for different misalignments and / or position errors.

[0132] Fig. 9 A holographic projection system 910 is shown, which includes one or more light (or laser) sources 912, a beam expander 914, a reflective device 916, an LCoS SLM 918, and a control module 920. The laser 912 generates a laser beam 922, which is received at the beam expander 914. The beam expander 914 expands the width of the laser beam 922 to provide an expanded beam 924. The reflective device 916 receives the expanded beam 924 and provides a reflected expanded beam 928, which is received at the LCoS SLM 918. The SLM 918 is encoded with a graphic hologram via the control module 920 and provides a projection beam 930, which is seen by the retina 932 of the viewer's eye 934. The control module 920 may include a display driver 940 for controlling the state of the reflective device 916 and / or the LCoS SLM 918. The LCoS SLM 118 may include a limiting aperture 950 to mitigate stray light. The limiting aperture 950 may be implemented as a frame that holds the LCoS SLM 918.

[0133] The reflective device 916 may be a reflective SLM or a micro-mirror array. When it is an SLM, the reflective device 916 is used to adjust the divergence angle and / or image size of the light source 912. In one embodiment, the reflective device (or SLM) 916 is used to fine-tune the beam size and position. This includes using the reflective device 916 to: (i) adjust the divergence angle of the beam using a lens hologram encoded on the reflective device 916 by the control module 920; (ii) shift (up, down, left and / or right) the projected image using a prism hologram encoded on the reflective device 916 by the control module 920; and / or (iii) compensate for the focal plane difference caused by the software lens phase hologram encoding. An exemplary focal plane 921 is shown. The reflective device 916 reflects and diffracts the received expanded beam at the LCoS SLM 918.

[0134] In one embodiment, the reflective means provided for each RGB light beam may be provided with a lens function to maintain the appropriate (same) size of the RGB light beams. The lens function may be used to compensate for the virtual image distance to maintain the same focal plane at the viewer's eye. Compensation may be provided for size errors occurring at the LCoS SLM downstream of the reflective means. The LCoS SLM may have different focal planes and a lens function implemented at the reflective means may be used to adjust the focal planes to be at the same position relative to the viewer's eye and / or a reference plane.

[0135] In one embodiment, for each of the three RGB light sources, Fig. 9 A configuration in which the divergence and position are controlled individually for each of the three RGB light sources. In this example, three light sources (red, green and blue light sources) are provided, such as Figure 5 , and includes 6 SLMs. A pair of SLMs is provided for each light source. Each pair of SLMs includes a first SLM (reflecting device) similar to reflecting device 916 and a second SLM similar to SLM 918. The second SLM in the pair may be an LCoS SLM, and its output may be provided to an X-cube combiner, for example, Figure 5 Displayed in.

[0136] The number of SLMs included depends on the speed of the SLMs. In one embodiment, 6 SLMs are included. In another embodiment, 4 SLMs are included. In yet another embodiment, 2 SLMs are included. In the 4 SLM embodiment, the configuration shown is for one light source and another version of the same configuration is used for two light sources, where the outputs of the two light sources are provided to the same beam expander via, for example, a combiner. In the 2 SLM embodiment, a single version of the configuration shown is used for all three light sources, where the outputs of the three light sources are provided to the same beam expander via, for example, a combiner.

[0137] Fig.10 An exemplary perspective view from a driver's seat of a vehicle 1000 is shown. The vehicle 1000 includes a windshield 1004 located in a front opening of the vehicle 1000. Passengers in a passenger compartment 1008 of the vehicle 1000 can see the front of the vehicle 1000 through the windshield 1004. Although examples of land-based vehicles are described, the present application is also applicable to air-based vehicles (e.g., airplanes, helicopters, etc.) and water-based vehicles (e.g., boats, etc.). Moreover, although some examples are disclosed herein with respect to vehicle embodiments, the examples are also applicable to non-vehicle embodiments.

[0138] like Fig.10 , a windshield 1004 is visually located above a dashboard 1006 of the vehicle 1000. The vehicle 1000 may include a steering wheel 1010. The vehicle 1000 may be an autonomous vehicle, a semi-autonomous vehicle, or a non-autonomous vehicle.

[0139] HUD systems (e.g., Figure 5-Figure 9 described) through the orifice 1016 in the instrument panel 1006 Fig.10 1004 is projected onto a portion of the windshield 1004. The hologram 1012 shown in FIG. 1004 is projected onto a portion of the windshield 1004. The hologram 1012 includes various vehicle information, such as the current speed of the vehicle 1000, the current gear of the transmission of the vehicle 1000, the engine speed, the directional heading of the vehicle 1000, the current infotainment system settings, and / or other vehicle information. The hologram 1012 presents the data to the driver of the vehicle without the driver having to look away from the object in front of the vehicle. As further discussed below, the hologram 1012 includes different color overlapping images that have the same size and are spatially aligned to provide a single image seen by the viewer, as described herein.

[0140] Fig.11 A HUD system 1100 is shown including a reflector 1102 of a vehicle and a control module 920 having a modified version thereof (identified as control module 920'). Fig. 9holographic projection system 910. In the example shown, the reflector is implemented as a windshield, but it can also be a different reflector. The control module 920' can perform the operations described above and additional operations, such as determining the vehicle information to be displayed via the reflector (or windshield 1102). The holographic projection system 910 includes one or more light sources (a laser 912 is shown), a beam expander 914, a reflection device 916, an LCoS SLM 918, and a control module 920'. The laser 912 generates a laser beam 922, which is received at the beam expander 914. The beam expander 914 expands the width of the laser beam 922 to provide an expanded beam 924. The reflection device 916 reflects the expanded beam 924 to provide a beam 928, which is received at the LCoS SLM 918. The LCoS SLM 918 provides a projection beam 930.

[0141] The control module 920' may include Fig. 9 The display driver 940 may be used to control the state of the reflective device 916 and / or the LCoS SLM 118. The display driver 940 may be implemented at the control module 920' and / or at the switching SLM 916 and / or the LCoS SLM 918. The LCoS SLM 918 may include a limiting aperture 950 to mitigate stray light. The limiting aperture 950 may be implemented as a frame to hold the LCoS SLM 918.

[0142] Fig.12 A holographic projection method is shown, which can be implemented by one of the holographic projection systems and corresponding control modules disclosed above. Figure 5-Figure 9 The following operations are described in the embodiment of the present disclosure, but the operations can be easily modified to apply to other embodiments of the present disclosure. The operations are provided as examples, and one or more of the operations may not be performed and / or skipped. The operations may be performed iteratively.

[0143] The method may start at 1200. At 1202, a control module (eg, one of control modules 502, 920, 920') activates an RGB light source to generate an RGB light (or laser) beam. As shown above, the beam may be directed to a lens, SLM, beam (or optical) expander.

[0144] At 1204, the control module may determine whether a single SLM is included for each of the RGB light sources. If so, operation 1206 may be performed, otherwise operation 1224 may be performed.

[0145] At 1206, the control module may determine whether to adjust the size of one or more of the generated light beams using one or more lenses, as described above. If so, operation 1208 may be performed, otherwise operation 1216 may be performed. At 1208, the control module may adjust the divergence angle of one or more of the RGB light beams via one or more lenses, as described above.

[0146] At 1210, the control module may determine whether to adjust the size of one or more of the RGB light beams via one or more SLMs. This may be done at one or more of the SLMs, LCoS SLMs, and / or reflective devices mentioned above. If yes, operation 1212 may be performed, otherwise operation 1214 may be performed.

[0147] At 1212, the control module may: (i) adjust the size of one or more of the RGB light beams using one or more lens holograms; and (ii) adjust the position of one or more of the RGB light beams using one or more prism holograms. One or more of the RGB light beams whose size is adjusted may be the same as or different from one or more of the RGB light beams whose position is adjusted. The position may be adjusted relative to a reference (e.g., a reference point) and / or relative to one or more of the other RGB light beams whose position is not adjusted.

[0148] At 1214, the control module can adjust the position of one or more of the RGB light beams using one or more prismatic holograms. The position can be adjusted relative to a reference (eg, a reference point) and / or relative to one or more of the other RGB light beams whose positions are not adjusted.

[0149] At 1216, the control module may determine whether to adjust the size using the pinhole layer of the SLM, as described above. If so, operation 1218 is performed, otherwise operation 1210 may be performed.

[0150] At 1218, the control module may determine whether to adjust the size via the SLM. If so, operation 1220 may be performed, otherwise operation 1222 may be performed. This may be done at one or more of any of the SLMs, LCoS SLMs, and / or reflective devices mentioned above. If so, operation 1220 may be performed, otherwise operation 1222 may be performed.

[0151] At 1220, the control module may: (i) adjust the divergence angle of one or more of the RGB beams via one or more pinhole layers of the corresponding SLM for one or more corresponding RGB beams; and (ii) adjust the size of one or more of the RGB beams via one or more corresponding lens holograms.

[0152] At 1222, the control module may adjust the divergence angle of one or more of the RGB light beams via one or more pinhole layers of the corresponding SLM for the one or more corresponding RGB light beams.

[0153] At 1224, for example, in the above relative Fig. 9 and Fig.11 In the depicted example, the control module may determine whether dual SLMs are used for each of the RGB light sources. If so, operation 1226 may be performed, otherwise operation 1228 may be performed.

[0154] At 1226, the control module may adjust the size(s) of one or more of the RGB light beams using one or more corresponding lens holograms and adjust the position(s) of one or more of the RGB light beams via one or more corresponding prism holograms at the first SLM (e.g., at the reflector 916). Fig.12 Not shown, but additional lens and / or prism holograms may be encoded on the second SLM after operation 1226.

[0155] At 1228, the control module may proceed to operation 1206 for a single SLM path and to operation 1226 for a dual SLM path. Operation 1230 may be performed after operations 1212, 1214, 1220, 1222, and 1226.

[0156] At 1230, the control module controls the operation of one or more LCoS SLMs to display a phase hologram of the graphic to be projected. Operation 1230 may be performed when operation 1212 and / or operation 1220 are performed. Each of the LCoS SLMs (which is encoded with a phase hologram of the graphic) is illuminated with a corresponding extended laser beam, and an encoded phase hologram beam is generated. If more than one beam is projected, the projected beams may be combined via a combiner. This may occur before operation 1232. One or more of the display drivers 940 may be used to generate a drive voltage to control the state of one or more LCoS SLMs.

[0157] At 1232, the RGB scene of the encoded phase hologram can be directed at the viewer's eyes so that the viewer sees a single graphic image. The phase hologram can be generated based on a signal from a vehicle control module. The control module can be implemented as a vehicle control module, or can communicate with a vehicle control module. The control module generates the phase hologram based on vehicle data. The control module can obtain the vehicle data, for example, from a communication bus of the vehicle. The vehicle data may include, for example, the current speed of the vehicle, the current gear of the vehicle's transmission, the current engine speed, the current direction heading of the vehicle, the current infotainment system settings, and / or other vehicle information. The method can end at 1234.

[0158] The operations described above are intended to be illustrative examples. Depending on the application, the operations may be performed sequentially, synchronously, simultaneously, continuously, during overlapping time periods, or in a different order. Moreover, depending on the implementation and / or sequence of events, any of the operations may not be performed or skipped.

[0159] The examples disclosed herein provide display assembly flexibility that allows for inaccurate alignment of optical components and accommodates wavelength-dependent optical properties of the components. Inaccurate alignment is compensated for by adjusting the size and position of the RGB light beams. The examples eliminate color misalignment associated with inaccurate overlap of images from separate RGB color channels in the eye box of the HUD. By selecting and adjusting the divergence angle of one or more RGB light beams to compensate for differences in wavelength for diffraction angle compensation, the examples achieve image size matching by resizing the RGB graphic images. An encoded software lens (e.g., a prismatic hologram) may be used for each of one or more of the RGB graphic holograms to spatially align size-matched images at the HUD eye box.

[0160] The control module disclosed herein may include graphics software to generate an image graphic via the LCoS SLM to align the image at the HUD eye box. This may be done, for example, at the LCoS SLM, which is encoded with a graphic hologram and includes using a reduced set of pixels or available image area for the corresponding beam generated. For example, the beam may be projected onto a portion of the available image area, and then the position of the beam may be moved within the available image area. This may be used for one or more of the RGB beams.

[0161] Fig.13 Shows Fig. 913. An example of an LCoS SLM 918 of FIG. 13. The LCoS SLM 918 may be used in any of the embodiments disclosed herein. The LCoS SLM 918 may include: a silicon backplane layer 1302; an LCoS SLM (or phase modulator) layer including a circuit (or pixelated electrode) layer 1304, a first alignment layer 1308, a liquid crystal layer 1310, a second alignment layer 1312, and a transparent electrode layer 1314; and a glass substrate layer 1316.

[0162] The circuit layer 1304 includes a control circuit system and / or a pixel driver for controlling the liquid crystal layer 1310. The circuit layer 1304 may include a transistor for each pixel. Each pixel individually modulates the phase of the light leaving the LCoS SLM. As an example, if the voltages provided to the pixels are different, the phases of the light rays leaving the corresponding parts of the LCoS SLM have different phases. Each of the pixels may have an associated voltage set. The voltage range provided to each pixel may, for example, change the phase of the corresponding part of the phase hologram beam 930 between 0-2π to advance or delay the corresponding part of the light wave leaving the LCoS SLM 918.

[0163] Circuit layer 1304 controls the amount and phase of light emitted from liquid crystal layer 1310. The orientation of molecules in liquid crystal layer 1310 and associated with the pixels of LCoS SLM 918 varies with voltage. The orientation of the molecules according to voltage induces a spatially varying phase distribution on LCoS SLM 918. Depending on the physical properties of the liquid crystal, the relationship between the modulated phase amount and the applied voltage can be positively or negatively correlated. Fig.14 The LCoS SLM layers are further described.When implemented as a reflective holographic projector, the LCoS SLM 918 may include a reflective film layer.

[0164] Fig.14 Shows the available Fig. 91400 and control module 920 of an LCoS SLM layer implemented in an embodiment of the present invention. The LCoS SLM layer may include pixels 1404 arranged in an array and connected to drive circuits 1406, 1408. The LCoS SLM layer may also include an SLM control module 1410, which may control the driver circuits 1406 and 1408. The driver circuits 1406, 1408 may receive power from the SLM control module 1410 or the control module 920 via switches 1407, 1409. The SLM control module 1410 may receive signals directly from the wavefront sensor and / or receive control signals from the control module 920. The control module 920 may receive the phase detection signal and control the operation of the SLM control module 1410 to adjust the voltage provided to the pixels 1404. In another embodiment, the SLM control module 1410 receives the phase detection signal directly and controls the drive circuits 1406 , 1408 to generate appropriate voltages applied at the pixels 1404 .

[0165] The foregoing description is merely illustrative in nature and is not intended to limit the present disclosure, its application or use in any way. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because other modifications will become apparent when studying the drawings, the specification and the following claims. It should be understood that one or more steps within the method may be performed in a different order (or simultaneously) without changing the principles of the present disclosure. In addition, although each of the embodiments is described above as having certain features, any one or more of those features described with respect to any embodiment of the present disclosure may be implemented and / or combined with any of the features in other embodiments, even if the combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and the permutation of one or more embodiments with each other remains within the scope of the present disclosure.

[0166] Various terms are used to describe the spatial and functional relationships between elements (e.g., between modules, circuit elements, layers, etc.) including "connected," "engaged," "coupled," "adjacent," "immediately adjacent," "on top," "above," "below," and "disposed." When describing the relationship between a first and a second element in the disclosure above, unless explicitly described as "directly," the relationship may be a direct relationship in which no other intermediate elements exist between the first and second elements, but may also be an indirect relationship in which one or more intermediate elements exist (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be interpreted to mean a logical (A or B or C) using a non-exclusive logical "or," and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C."

[0167] In the drawings, the direction of the arrows (as indicated by the arrows) generally represents the flow of information (e.g., data or instructions) that the illustration is concerned with. For example, when element A and element B exchange various information but the information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. In addition, for information sent from element A to element B, element B may send a request for the information or an acknowledgement of receipt of the information to element A.

[0168] In this application (including the definitions below), the term "circuit" may be used instead of the term "module" or the term "controller". The term "module" may refer to, be part of, or include: an application specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, for example, in a system on a chip.

Claims

1. Holographic projection system, including: a first light source configured to generate a first light beam; a second light source configured to generate a second light beam; a third light source configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths; a plurality of spatial light modulators configured to diffract the first light beam, the second light beam, and the third light beam, respectively; a first lens configured to adjust a divergence angle of one of the first light beam, the second light beam, or the third light beam so that diffracted light exiting from each of the plurality of spatial light modulators is at the same diffraction angle, wherein the first lens adjusts the divergence angle of one of the first light beam, the second light beam, or the third light beam before one of the first light beam, the second light beam, or the third light beam is received at one of the plurality of spatial light modulators, wherein the plurality of spatial light modulators are configured to encode a phase hologram including a corresponding version of a graphic image based on light generated by the first light source, the second light source, and the third light source, including light output from the first lens, to provide a phase hologram light beam; a combiner configured to combine the phase hologram beams to provide a combined phase hologram beam, the combined phase hologram beam being projected for viewing a combined graphic image; and A control module is configured to encode a prismatic hologram on one of the plurality of spatial light modulators to align outputs of the plurality of spatial light modulators.

2. The holographic projection system according to claim 1, wherein: The first light beam is a red laser beam; The second light beam is a green laser light beam; and The third light beam is a blue laser light beam.

3. The holographic projection system according to claim 2, further comprising a second lens, wherein: The first lens adjusts a divergence angle of the green laser beam to match a divergence angle of the red laser beam diffracted by one of the plurality of spatial light modulators; as well as The second lens adjusts a divergence angle of the blue laser beam to match a divergence angle of the red laser beam diffracted by one of the plurality of spatial light modulators.

4. The holographic projection system according to claim 2, wherein: The first lens adjusts a divergence angle of the red laser beam to match a divergence angle of the green laser beam diffracted by one of the plurality of spatial light modulators.

5. The holographic projection system according to claim 4, wherein: The holographic projection system lacks a lens for adjusting the divergence angle of the blue laser light beam.

6. The holographic projection system according to claim 1, wherein: One or more of the plurality of spatial light modulators includes a non-periodic photon sieve layer to adjust a divergence angle of one or more of the first light beam, the second light beam, and the third light beam.

7. The holographic projection system according to claim 1, wherein: The control module is configured to encode a lens hologram on one or more of the plurality of spatial light modulators to adjust a size of one or more of the first light beam, the second light beam, and the third light beam.

8. The holographic projection system according to claim 1, wherein: The control module is configured to encode two prismatic holograms on two of the plurality of spatial light modulators, respectively, to shift positions of two of the first light beam, the second light beam, and the third light beam.

9. The holographic projection system according to claim 1, wherein: The control module is configured to (1) size the first beam, the second beam, and the third beam so as not to fill an available image area, and (2) adjust a position of one or more of the first beam, the second beam, and the third beam so as to align the first beam, the second beam, and the third beam.

10. Holographic projection system, including: a first light source configured to generate a first light beam; a second light source configured to generate a second light beam; a third light source configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths; a plurality of spatial light modulators configured to encode a phase hologram including a corresponding version of a graphic image based on light generated by the first light source, the second light source, and the third light source to provide a phase hologram light beam, wherein a first one of the spatial light modulators includes a first non-periodic photon sieve layer, and wherein the first non-periodic photon sieve layer is configured to adjust a divergence angle of one of the first light beam, the second light beam, or the third light beam so that diffracted light exiting from each of the plurality of spatial light modulators is at a same diffraction angle; a combiner configured to combine the phase hologram beams to provide a combined phase hologram beam, the combined phase hologram beam being projected for viewing a combined graphic image; and A control module is configured to encode a prismatic hologram on one of the plurality of spatial light modulators to align outputs of the plurality of spatial light modulators.

11. The holographic projection system according to claim 10, wherein: The first of the plurality of spatial light modulators that includes the first non-periodic photon sieve layer is the same spatial light modulator for which the control module encodes the prismatic hologram.

12. The holographic projection system according to claim 10, wherein: The first of the plurality of spatial light modulators that includes the first non-periodic photon sieve layer is a different spatial light modulator for which the control module encodes the prismatic hologram.

13. The holographic projection system according to claim 10, wherein: The first light beam is a red laser beam; The second light beam is a green laser light beam; and The third light beam is a blue laser light beam.

14. The holographic projection system according to claim 13, wherein: The first one of the plurality of spatial light modulators receives the green laser beam; A second one of the plurality of spatial light modulators receives the blue laser beam and includes a second non-periodic photon sieve layer; The first non-periodic photon sieve layer adjusts the divergence angle of the green laser beam to match the divergence angle of the red laser beam diffracted by a third one of the plurality of spatial light modulators; as well as The second non-periodic photon sieve layer adjusts a divergence angle of the blue laser beam to match a divergence angle of the red laser beam diffracted by the third of the plurality of spatial light modulators.

15. The holographic projection system according to claim 13, wherein: The first non-periodic photon sieve layer adjusts a divergence angle of the red laser beam to match a divergence angle of the green laser beam diffracted by the first of the plurality of spatial light modulators.

16. The holographic projection system according to claim 15, wherein: The holographic projection system lacks a non-periodic photon sieve layer for adjusting the divergence angle of the blue laser light beam.

17. Holographic projection system, including: a first light source configured to generate a first light beam; a second light source configured to generate a second light beam; a third light source configured to generate a third light beam, wherein the first light beam, the second light beam, and the third light beam have corresponding wavelengths; a plurality of spatial light modulators configured to encode a phase hologram comprising a graphical image, the graphical image being generated based on a combination of light from the first light beam, the second light beam, and the third light beam; as well as The control module is configured as encoding one or more lens holograms on a first one or more of the plurality of spatial light modulators to adjust a size of another of the first, second, or third light beams relative to one of the first, second, or third light beams, and One or more prismatic holograms are encoded on a second one or more of the plurality of spatial light modulators to align the first light beam, the second light beam, and the third light beam.

18. The holographic projection system according to claim 17, further comprising a combiner for: combining the outputs of three of the plurality of spatial light modulators to provide a combined phase hologram beam, the combined phase hologram beam being projected for viewing a combined graphic image; or The outputs of the first, second, and third light sources are combined before the first, second, and third light beams are received at the plurality of spatial light modulators.

19. The holographic projection system according to claim 17, wherein: The plurality of spatial light modulators comprises: a first spatial light modulator; and a second spatial light modulator, downstream of said first spatial light modulator, Wherein, the control module is configured as encoding at least one of a lens hologram or a prismatic hologram on the first spatial light modulator, and The graphical image is encoded on the second spatial light modulator.

20. The holographic projection system according to claim 19, wherein: The plurality of spatial light modulators comprises: a third spatial light modulator; and a fourth spatial light modulator, downstream of the first spatial light modulator, in, The first spatial light modulator receives the first light beam, The third spatial light modulator receives the second light beam, and The control module is configured to encoding at least one of a lens hologram or a prismatic hologram on the third spatial light modulator, and The graphical image is encoded on the second spatial light modulator and the fourth spatial light modulator.

21. The holographic projection system according to claim 17 further comprises a first lens, which is configured to adjust the divergence angle of one of the first light beam, the second light beam or the third light beam so that the diffracted light leaving each of the multiple spatial light modulators is at the same diffraction angle, wherein the first lens adjusts the divergence angle of one of the first light beam, the second light beam or the third light beam before the first light beam, the second light beam or the third light beam is received at one of the multiple spatial light modulators.

Images