Multi-depth plane head-up display system

Abstract

The invention relates to the field of photoelectric display, in particular to a multi-depth plane head-up display system, which comprises a light source, a projection system, a composite holographic compensator and a composite holographic image synthesizer, and is characterized in that the light source is used for illuminating the projection system; the projection system is used for editing original three-dimensional image information to generate image information with more than two depths, and projecting the image information with more than two depths to the composite holographic compensator; the composite holographic compensator is used for performing error compensation on the image information of more than two depths, and the error compensation comprises one or more of aberration compensation, speckle error compensation and dispersion error compensation; and the composite holographic image synthesizer is used for receiving the light transmitted by the projection system and the composite holographic compensator and projecting image information to more than two depth planes of a three-dimensional space to obtain more than two depth display images. And a multi-depth plane image with high resolution, no speckle and large depth of field can be formed.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic display, and particularly to a multi-depth planar head-up display system. Background Art

[0002] The head-up display system combines optoelectronic display and optical imaging technologies to project auxiliary driving information into the field of view in front of the driver, which can reduce the driver's perspective switching and contribute to improving driving safety, and is widely used in transportation tools such as airplanes and automobiles. Currently, commercially available head-up display systems can only provide the driver with image information of a single depth plane. This display method cannot meet the requirements of complex traffic environments. The traffic environment is a three-dimensional space, and auxiliary driving information may need to be projected to any depth position in the three-dimensional space. Currently, three-dimensional head-up displays have problems such as large computational load, speckle contamination, limited resolution, complex systems, and slow dynamic response speed. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to overcome the shortcomings in the background art and provide a multi-depth planar head-up display system with high resolution, no speckle, and large depth of field.

[0004] The purpose of the present invention is achieved through the following technical solutions: A multi-depth planar head-up display system includes a light source, a projection system, a composite holographic compensator, and a composite holographic image synthesizer. The light source is used to illuminate the projection system; the projection system is used to edit the original three-dimensional image information to generate image information with two or more depths, and project the image information with two or more depths onto the composite holographic compensator; the composite holographic compensator is used to perform error compensation on the image information with two or more depths respectively, and the error compensation includes one or several of aberration compensation, speckle error compensation, and chromatic dispersion error compensation; the composite holographic image synthesizer is used to receive the light rays transmitted by the projection system and the composite holographic compensator, and project the image information onto two or more depth planes in the three-dimensional space to obtain planar display images with two or more depths.

[0005] In the multi-depth planar head-up display system according to the embodiment of the present invention, the light source illuminates the projection system, and the projection system generates driving assistance information. The driving assistance information is first projected onto the composite holographic compensator, and the composite holographic compensator performs error compensation on the driving assistance information at different depths respectively. The compensation includes compensating for one or more errors such as aberration, speckle, and chromatic dispersion. The light rays reflected or transmitted by the composite holographic compensator enter the composite holographic image synthesizer, and the composite holographic image synthesizer projects the image onto multiple depth planes in the three-dimensional space. The driver can see a real-time multi-depth planar head-up display image with high resolution, no speckle, and large depth of field through the composite holographic image synthesizer.

[0006] Among them, the composite holographic compensator is used to reflect or transmit light and make the light enter the composite holographic image synthesizer.

[0007] Among them, the composite holographic compensator includes a composite holographic element, and the composite holographic element includes more than two sub-compensation parts. One sub-compensation part is used to compensate for the error of the wavefront carrying the depth plane image information of one depth, and the other sub-compensation part is used to compensate for the error of the wavefront carrying the depth plane image information of another depth. Different sub-compensation parts are used for compensation at different depths. That is to say, one sub-compensation part can compensate for the error of the wavefront of one depth. Each compensation part is encoded with wavefront information conjugate to the error of the wavefront corresponding to the depth plane image information, so as to achieve the effect of compensating for the error of the wavefront of the plane image information at different depths, and can achieve the compensation of speckle, aberration, and chromatic dispersion, so that the obtained plane display images at multiple depths are free of speckle, have high resolution, and are free of chromatic dispersion or have weak chromatic dispersion. In the embodiment of the present invention, the composite holographic element of the composite holographic compensator is divided into more than two regions, and each region respectively compensates for the error of the wavefront carrying the depth plane image information of different depths, so that the obtained plane display images at multiple depths are free of speckle, have high resolution, and are free of chromatic dispersion or have weak chromatic dispersion.

[0008] Among them, the composite holographic element includes one or several of a hologram, a phase plate, and a holographic grating. The composite holographic element is encoded with wavefront information conjugate to the wavefront error of the specific depth plane image information. The conjugate wavefront information can cancel out the original wavefront information with errors to achieve the compensation effect.

[0009] Among them, the composite holographic compensator further includes a scattering screen, and the scattering screen is used to receive the light transmitted by the composite holographic element and transmit it to the composite holographic image synthesizer. By setting the scattering screen in the embodiment of the present application, scattering can be increased, which is beneficial to increasing the viewing angle of the plane display images at more than two depths.

[0010] Among them, the composite holographic image synthesizer is divided into more than two sub-holographic image synthesizers. One of the sub-holographic image synthesizers is used to receive the light transmitted by one sub-compensation part and synthesize a plane display image of one depth; the other sub-holographic image synthesizer is used to receive the light transmitted by another sub-compensation part and synthesize a plane display image of another depth. The composite holographic image synthesizer in the embodiment of the present invention is divided into more than two regions, and each region corresponds to a sub-compensation part (a region of the composite holographic element) and is used to synthesize a plane display image of one depth respectively.

[0011] Among them, the sub-holographic image synthesizer includes one or more of a holographic optical lens imaging synthesizer, a holographic optical mirror reflection synthesizer, and a holographic optical scattering imaging synthesizer. Each region of the embodiment of the present invention has different optical imaging functions, and the optical imaging functions include but are not limited to holographic optical lens imaging functions, holographic optical mirror reflection functions, and holographic optical scattering imaging functions.

[0012] Among them, two or more sub-holographic image synthesizers include two holographic optical lens imaging synthesizers, and the optical power of one holographic optical lens synthesizer is different from that of the other holographic optical lens synthesizer. In the embodiment of the present invention, the optical imaging lenses of the holographic optical imaging lens synthesizer have different optical powers, which is convenient for synthesizing images with different depths.

[0013] Among them, two or more sub-holographic image synthesizers include a combination of two or more of a holographic optical lens imaging synthesizer, a holographic optical mirror reflection synthesizer, and a holographic optical scattering imaging synthesizer.

[0014] Preferably, the holographic optical scattering imaging synthesizer has the characteristics of band-limited and directional scattering. The holographic optical scattering imaging synthesizer having the characteristics of band-limited and directional scattering can improve the light energy utilization rate, thereby enhancing the display brightness and contrast.

[0015] Among them, the light source includes a coherent light source and / or an incoherent light source. The coherent light source includes a solid laser and / or a laser diode. The incoherent light source includes an LED and / or a super-radiant tube. The light source of the multi-depth plane head-up display system in the embodiment of the present invention can be a coherent light source, an incoherent light source, or both a coherent light source and an incoherent light source at the same time, and there is no limitation on the light source.

[0016] Among them, the projection system includes one or more of a projection system with Fourier transform function, a non-focal projection system, and a large-depth-of-field projection system.

[0017] In this application, the large-depth-of-field projection system refers to a projection system with a depth of field greater than or equal to 50 mm.

[0018] Among them, the projection system includes a polarization beam splitter, a liquid crystal on silicon (LCOS) spatial light modulator, and a projection lens. The polarization beam splitter is used to receive the light from the light source and reflect the light to the LCOS spatial light modulator. The light reflected from the LCOS spatial light modulator passes through the polarization beam splitter, and the light passing through the polarization beam splitter is transformed and projected onto the composite holographic compensator by the projection lens. Or, the projection system includes a total reflection prism, a digital micromirror device (DMD), and a projection lens. The light emitted by the light source is reflected to the DMD by the total reflection prism, and the light is reflected from the DMD to the total reflection prism and then transmitted to the projection lens. The projection lens transforms and projects the light onto the composite holographic compensator. Or, the projection system includes a digital galvanometer with two-dimensional vibration and a control system.

[0019] In the embodiments of the present invention, editing and generating image information with more than two depths includes encoded driving assistance information. The image information with more than two depths includes two or more depth information and image information.

[0020] Due to the application of the above technical solutions, the present invention has the following beneficial effects compared with the prior art:

[0021] 1. The present invention breaks through the limitation of the huge computational amount of traditional holographic head-up displays, realizes multi-depth head-up display by using a simple image source, avoids the complex diffraction calculation process in the holographic encoding process of depth information, and has a small computational amount.

[0022] 2. The present invention solves the aberration problem of the holographic image synthesizer and realizes high-resolution multi-depth head-up display.

[0023] 3. The present invention breaks through the limitation of coherent light sources, solves the speckle problem under coherent light illumination conditions, and realizes high-resolution speckle-free multi-depth head-up display.

[0024] 4. The present invention breaks through the limitation of incoherent light sources, solves the chromatic dispersion problem under incoherent light illumination conditions, and realizes high-resolution multi-depth head-up display.

[0025] 5. The multi-depth planar head-up display system of the present invention can form display images with more than two depth planes with high resolution and no speckle, and has a large depth of field. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the first embodiment of the multi-depth planar head-up display system of the present application.

[0027] Figure 2 is a schematic structural diagram of the second embodiment of the multi-depth planar head-up display system of the present application.

[0028] Figure 3It is a schematic structural diagram of the third embodiment of the multi-depth plane head-up display system of the present application.

[0029] Figure 4 It is a schematic structural diagram of the fourth embodiment of the multi-depth plane head-up display system of the present application.

[0030] Figure 5 It is a schematic structural diagram of the fifth embodiment of the multi-depth plane head-up display system of the present application.

[0031] Figure 6 It is a schematic structural diagram of the sixth embodiment of the multi-depth plane head-up display system of the present application.

[0032] Embodiment

[0033] Hereinafter, embodiments of the multi-depth plane head-up display system of the present invention are specifically disclosed in detail with appropriate reference to the accompanying drawings. However, there may be cases where unnecessary detailed descriptions are omitted. For example, there are cases where detailed descriptions of well-known matters and repeated descriptions of actually identical structures are omitted. This is to avoid the following descriptions from becoming unnecessarily lengthy and to facilitate the understanding of those skilled in the art. In addition, the accompanying drawings and the following descriptions are provided for those skilled in the art to fully understand the present invention and are not intended to limit the subject matter recited in the claims.

[0034] If there is no special description, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0035] If there is no special description, all technical features and optional technical features of the present invention can be combined with each other to form new technical solutions.

[0036] If there is no special description, the terms "comprising" and "including" mentioned in the present invention mean open-ended and can also be closed-ended. For example, "comprising" and "including" can mean that other structural members not listed can also be included or contained, or can only include or contain the listed structural members.

[0037] If there is no special description, in the present invention, the term "or" is inclusive. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, any of the following conditions satisfies the condition "A or B": A is true (or exists) and B is false (or does not exist); A is false (or does not exist) while B is true (or exists); or both A and B are true (or exist).

[0038] To make the technical problems, technical solutions and beneficial effects solved by the embodiments of the present invention clearer, the following will further elaborate in detail in combination with the embodiments and the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way constitutes any limitation to the present invention and its application. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0039] In the related art, the methods that can achieve three-dimensional head-up display include holographic head-up display, light field head-up display, zoom projection, etc. However, holographic head-up displays have problems such as large computational load, speckle contamination, and laser safety. The resolution of light field head-up displays is limited. Zoom projection systems have problems such as complexity and slow dynamic response speed. The existence of these problems is an important bottleneck for the application of multi-depth plane head-up display systems.

[0040] Therefore, the present invention provides a multi-depth plane head-up display system. For the convenience of understanding, the following specific embodiments are provided by the present invention for easy understanding.

[0041] Embodiment 1

[0042] See Figure 1 , which is a schematic structural diagram of a multi-depth plane head-up display system in this embodiment. The multi-depth plane head-up display system in this embodiment includes a light source 1, a projection system 2, a composite holographic compensator 3, and a composite holographic image synthesizer 4. The light source includes a solid-state laser 11 and a beam expander collimator 12.

[0043] In the embodiments of the present application, the projection system 2 has a Fourier transform function. The projection system 2 includes a liquid crystal on silicon spatial light modulator 21, a polarization beam splitter 22, and a projection lens 23. The liquid crystal on silicon spatial light modulator 21 is located near the focal length of the projection lens 23. In the embodiments of the present application, the projection system 2 is used to edit the original three-dimensional image information to generate image information with three depths, and project the image information with three depths onto the composite holographic compensator 3.

[0044] In the embodiments of the present application, the composite holographic compensator 3 is composed of a composite holographic element 31 and a scattering screen 32. The composite holographic element 31 includes three sub-compensation parts. For the convenience of distinction, the three different sub-compensation parts are the first sub-compensation part 311, the second sub-compensation part 312, and the third sub-compensation part 313 respectively. The three sub-compensation parts can compensate for the aberration and speckle of images with three different depths. In the embodiments of the present application, the three sub-compensation parts are located in three different regions of the composite holographic element 31.

[0045] In the embodiments of the present application, the composite holographic image synthesizer 4 includes three sub-holographic image synthesizers. For the convenience of distinction, the three sub-holographic image synthesizers are the first sub-holographic image synthesizer 41, the second sub-holographic image synthesizer 42, and the third sub-holographic image synthesizer 43 respectively. In the embodiments of the present application, the three sub-holographic image synthesizers can be integrated into one body, and the three sub-holographic images are in different regions. In other embodiments, the three sub-holographic image synthesizers can also be of a split structure.

[0046] In the embodiments of the present application, the first sub-holographic image synthesizer 41 has the function of an optical imaging lens and is a holographic optical lens imaging synthesizer; the second sub-holographic image synthesizer 42 has the function of an optical mirror surface and is a holographic optical mirror surface reflection synthesizer; the third sub-holographic image synthesizer 43 has the function of optical scattering imaging and is a holographic optical scattering imaging synthesizer. The first sub-holographic image synthesizer 41 is responsible for forming the far image 63, the second sub-holographic image synthesizer 42 is responsible for forming the middle image 62, and the third sub-holographic image synthesizer 43 is responsible for forming the near image 63.

[0047] The first sub-compensation part 311 in the composite holographic element 31 is a hologram, which is composed of micro-nano scale holographic fringes located inside the first sub-compensation part 311. The holographic fringes are formed by the interference of a reference light and a wavefront encoded with speckle noise negatively correlated with that formed by the third sub-holographic image synthesizer 43 during the scattering imaging process and recorded. The second sub-compensation part 312 in the composite holographic element 31 is a holographic grating, which is composed of micro-nano scale grating fringes located inside the second sub-compensation part 312. The grating fringes are formed by the interference of a reference light and a wavefront encoded with the aberration conjugate of that in the optical mirror surface imaging process of the second sub-holographic image synthesizer 42 and recorded. The third sub-compensation part 313 in the composite holographic element 31 is a phase plate, which is composed of a micro-nano scale surface relief structure. The surface relief structure encodes the wavefront information conjugate to the aberration in the optical imaging process of the first sub-holographic image synthesizer 41.

[0048] The first sub-compensation part 311 compensates for the aberration, speckle or chromatic dispersion of the third sub-holographic image synthesizer 43 in the subsequent composite holographic image synthesizer 4. The second sub-compensation part 312 compensates for the aberration, speckle or chromatic dispersion of the second sub-holographic image synthesizer 42 in the subsequent composite holographic image synthesizer 4. The third sub-compensation part 313 compensates for the aberration, speckle or chromatic dispersion of the first sub-holographic image synthesizer 41 in the subsequent composite holographic image synthesizer 4. That is, the sub-compensation parts 311, 312 and 313 compensate for the aberration, speckle or chromatic dispersion in different regions corresponding to the sub-holographic image synthesizers 43, 42 and 41 in the subsequent composite holographic image synthesizer 4.

[0049] In the embodiment of the present application, the first sub-holographic image synthesizer 41 includes a holographic optical lens imaging synthesizer, which is an optical lens composed of a micro-nano structure formed by the interference of a plane wave and a spherical wave and stored in the first sub-holographic image synthesizer 41.

[0050] In the embodiment of the present application, the second sub-holographic image synthesizer 42 includes a holographic optical mirror reflection synthesizer, which is an optical mirror composed of a micro-nano structure formed by the interference of two plane waves and stored in the first sub-holographic image synthesizer 41.

[0051] In the embodiment of the present application, the third sub-holographic image synthesizer 43 includes a holographic optical scattering imaging synthesizer, which is a holographic scatter mirror composed of a micro-nano structure formed by the interference of a scattered wavefront and a plane wave and stored in the third sub-holographic image synthesizer 43.

[0052] The optical path principle of the multi-depth plane head-up display system according to the embodiment of the present application: The solid-state laser 11 emits a laser, which is reflected and then enters the collimating and beam-expanding device 12 to form a collimated illumination wide beam. The collimated illumination wide beam enters the projection system 2. The collimated wide beam is first reflected by the polarization beam splitter 22 to the liquid crystal on silicon spatial light modulator 21, and the light reflected from the spatial light modulator 21 passes through the polarization beam splitter 22 and is transformed and projected by the projection lens 23 onto the first sub-compensation part 311, the second sub-compensation part 312, and the third sub-compensation part 313 of the composite holographic optical element 3. The reflected light on the composite holographic optical element passes through the scattering screen 32 and its periphery and then illuminates the third sub-holographic image synthesizer 43, the second sub-holographic image synthesizer 42, and the first sub-holographic image synthesizer 41 of the composite holographic image synthesizer 4, forming images 61, 62, and 63 with different depths. And it is received by the observer's eyes 5.

[0053] Taking the formation of three images 61, 62, and 63 with different depths as an example in the embodiment of the present application, in other embodiments, the number of sub-compensators and sub-holographic image synthesizers can also be adjusted to form four or more than five images with different depths.

[0054] Embodiment 2

[0055] See Figure 2 , which is a schematic structural diagram of a multi-depth plane head-up display system in this embodiment. The multi-depth plane head-up display system in this embodiment includes a light source 1, a projection system 2, a composite holographic compensator 3, and a composite holographic image synthesizer 4. The light source includes a light-emitting diode (LED) 13 and a collimating mirror group 14.

[0056] In the embodiment of the present application, the projection system 2 has a large depth of field projection function. The projection system includes a digital micromirror device 24, a total reflection prism 25, and a large depth of field projection lens 26. The projection system 2 is used to edit the original three-dimensional image information to generate image information with three depths, and project the image information with three depths onto the composite holographic compensator 3.

[0057] In the embodiment of the present application, the composite holographic compensator 3 includes a composite holographic element 31 and a scattering screen 32. The composite holographic element 31 includes three sub-compensation parts. For the convenience of distinction, the three different sub-compensation parts are respectively a first sub-compensation part 311, a second sub-compensation part 312, and a third sub-compensation part 313. The three sub-compensation parts can compensate for the aberration and speckle of images with three different depths. In the embodiment of the present application, the three sub-compensation parts are located in three different regions of the composite holographic element 31.

[0058] In the embodiment of the present application, the composite holographic image synthesizer 4 includes three sub-holographic image synthesizers. For the convenience of distinction, the three sub-holographic image synthesizers are respectively a first sub-holographic image synthesizer 41, a second sub-holographic image synthesizer 42, and a third sub-holographic image synthesizer 43. In the embodiment of the present application, the three sub-holographic image synthesizers can be integrated into one body, and the three sub-holographic images are in different regions. In other embodiments, the three sub-holographic image synthesizers can also be in a split structure.

[0059] In the embodiment of the present application, the first sub-holographic image synthesizer 41 has an optical imaging lens function and is a holographic optical lens imaging synthesizer; the second sub-holographic image synthesizer 42 has an optical mirror surface function and is a holographic optical mirror surface reflection synthesizer; the third sub-holographic image synthesizer 43 has an optical scattering imaging function and is a holographic optical scattering imaging synthesizer. The first sub-holographic image synthesizer 41 forms a far image 63, the second sub-holographic image synthesizer 42 forms a middle image 62, and the third sub-holographic image synthesizer 43 forms a near image 61.

[0060] The first sub-compensation part 311 in the composite holographic element 31 is a hologram, which is composed of micro-nano scale holographic fringes located inside the first sub-compensation part 311. The holographic fringes are formed by interfering and recording a reference light and a wavefront encoded with speckle noise negatively correlated with that formed during the scattering imaging process by the third sub-holographic image synthesizer 43. The second sub-compensation part 312 in the composite holographic element 31 is a holographic grating, which is composed of micro-nano scale grating fringes located inside the second sub-compensation part 312. The grating fringes are formed by interfering and recording a reference light and a wavefront encoded with the dispersion conjugate during the optical mirror imaging process by the second sub-holographic image synthesizer 42. The third sub-compensation part 313 in the composite holographic element 31 is a phase plate, which is composed of a micro-nano scale surface relief structure. The surface relief structure encodes wavefront information conjugate to the aberration and dispersion during the optical imaging process by the first sub-holographic image synthesizer 41.

[0061] The first sub-compensation part 311 compensates for the aberration, speckle or dispersion of the third sub-holographic image synthesizer 43 in the subsequent composite holographic image synthesizer 4. The second sub-compensation part 312 compensates for the aberration, speckle or dispersion of the second sub-holographic image synthesizer 42 in the subsequent composite holographic image synthesizer 4. The third sub-compensation part 313 compensates for the aberration, speckle or dispersion of the first sub-holographic image synthesizer 41 in the subsequent composite holographic image synthesizer 4. That is, the sub-compensation parts 311, 312 and 313 compensate for the aberration, speckle or dispersion in different regions corresponding to the sub-holographic image synthesizers 43, 42 and 41 in the subsequent composite holographic image synthesizer 4.

[0062] The first sub-holographic image synthesizer 41 includes a holographic optical lens imaging synthesizer, which is an optical lens composed of a micro-nano structure formed by the interference of a plane wave and a spherical wave stored in the first sub-holographic image synthesizer 41.

[0063] The second sub-holographic image synthesizer 42 includes a holographic optical mirror reflection synthesizer, which is an optical mirror composed of a micro-nano structure formed by the interference of two plane waves stored in the first sub-holographic image synthesizer 41.

[0064] The third sub-holographic image synthesizer 43 includes a holographic optical scattering imaging synthesizer, which is a holographic scatter mirror composed of a micro-nano structure formed by the interference of a scattered wavefront and a plane wave stored in the third sub-holographic image synthesizer 43.

[0065] The light emitted by the light-emitting diode (LED) 13 forms a collimated illumination wide beam after passing through the collimating lens group 14. The collimated illumination wide beam enters the projection system 2. The collimated wide beam is first reflected by the total reflection prism 25 and then illuminates the digital micromirror device 24. The light is reflected from the digital micromirror device 24, passes through the total reflection prism 25, and is then transformed by the projection lens 26 and projected onto the first sub-compensation part 311, the second sub-compensation part 312, and the third sub-compensation part 313 of the composite holographic element 31. The reflected light of the composite holographic element 31 illuminates the third sub-holographic image synthesizer 43, the second sub-holographic image synthesizer 42, and the first sub-holographic image synthesizer 41 of the composite holographic image synthesizer 4 through the scattering screen 32 and its periphery, forming images 61, 62, and 63 with different depths. And it is received by the observer's eye 5.

[0066] Embodiment 3

[0067] See Figure 3 , which is a schematic structural diagram of a multi-depth planar head-up display system in this embodiment. The multi-depth planar head-up display system in this embodiment includes a light source 1, a projection system 2, a composite holographic compensator 3, and a composite holographic image synthesizer 4. The light source 1 includes a laser, a color combiner 18, and a shaping mirror 19. The laser includes a red laser 15, a green laser 16, and a blue laser 17.

[0068] In the embodiment of the present application, the projection system 2 is a afocal projection system. The projection system includes a digital galvanometer 27 that can vibrate two-dimensionally and a control system 28. The control system 28 coordinates the switching of the three-color lasers 15, 16, and 17 and the vibration of the digital galvanometer 27.

[0069] In the embodiment of the present application, the composite holographic compensator 3 includes a composite holographic element 31 and a scattering screen 32. The composite holographic element 31 includes three sub-compensation parts. For the convenience of distinction, the three different sub-compensation parts are the first sub-compensation part 311, the second sub-compensation part 312, and the third sub-compensation part 313 respectively. The three sub-compensation parts can compensate for the aberration and speckle of the images with three different depths. In the embodiment of the present application, the three sub-compensation parts are located in three different regions of the composite holographic element 31.

[0070] In the embodiment of the present application, the composite holographic image synthesizer 4 includes three sub-holographic image synthesizers. For the convenience of distinction, the three sub-holographic image synthesizers are the first sub-holographic image synthesizer 41, the fourth sub-holographic image synthesizer 44, and the fifth sub-holographic image synthesizer 45 respectively. The first sub-holographic image synthesizer 41, the fourth sub-holographic image synthesizer 44, and the fifth sub-holographic image synthesizer 45 are all holographic optical lens imaging synthesizers, and their focal lengths are different. The first sub-holographic image synthesizer 41 has the function of an optical imaging lens, and its focal length is F1; the fourth sub-holographic image synthesizer 44 has the function of an optical imaging lens, and its focal length is F2; the fifth sub-holographic image synthesizer 45 has the function of an optical imaging lens, and its focal length is F3. The first sub-holographic image synthesizer 41 is used to form a far image 63, the fourth sub-holographic image synthesizer 44 is used to form a middle image 62, and the fifth sub-holographic image synthesizer 45 is used to form a near image 61.

[0071] In the embodiment of the present application, the first sub-compensation part 311 in the composite holographic element 31 is a hologram, and this hologram is composed of micro-nano scale holographic fringes located inside the first sub-compensation part 311. The holographic fringes are formed by the interference and recording of a reference light and a wavefront encoded with the aberration conjugate of the fifth sub-holographic image synthesizer 45 during the imaging process. The second sub-compensation part 312 in the composite holographic element 31 is a hologram, and this holographic light pattern is composed of micro-nano scale holographic fringes located inside the second sub-compensation part 312. The grating fringes are formed by the interference and recording of a reference light and a wavefront encoded with the aberration and dispersion conjugate of the fourth sub-holographic image synthesizer 44 during the optical lens imaging process. The third sub-compensation part 313 in the composite holographic element 31 is a phase plate, and this phase plate is composed of a micro-nano scale surface relief structure. The surface relief structure encodes the wavefront information conjugate to the aberration and dispersion of the first sub-holographic image synthesizer 41 during the optical lens imaging process.

[0072] In the embodiment of the present application, the first sub-compensation part 311 compensates for the aberration and speckle of the fifth sub-holographic image synthesizer 45 in the subsequent composite holographic image synthesizer 4. The second sub-compensation part 312 compensates for the aberration and speckle of the fourth sub-holographic image synthesizer 44 in the subsequent composite holographic image synthesizer 4. The third sub-compensation part 313 compensates for the aberration and speckle of the first sub-holographic image synthesizer 41 in the subsequent composite holographic image synthesizer 4. That is, the sub-compensation parts 311, 312, and 313 compensate for the aberration and speckle in different regions corresponding to the fifth sub-holographic image synthesizer 45, the fourth sub-holographic image synthesizer 44, and the first sub-holographic image synthesizer 41 in the subsequent composite holographic image synthesizer 4.

[0073] The first sub-holographic image synthesizer 41 includes a holographic optical lens imaging synthesizer, which is composed of a micro-nano structure formed by the interference of a plane wave and a spherical wave stored in the first sub-holographic image synthesizer 41, and has a focal length of F1.

[0074] In the embodiment of the present application, the fourth sub-holographic image synthesizer 44 includes a holographic optical lens imaging synthesizer, which is composed of a micro-nano structure formed by the interference of a spherical wave and a spherical wave stored in the fourth sub-holographic image synthesizer 44, and has a focal length of F2.

[0075] In the embodiment of the present application, the fifth sub-holographic image synthesizer 45 includes a holographic optical lens imaging synthesizer, which is a holographic lens, and is composed of a micro-nano structure formed by the interference of a spherical wave and a spherical wave stored in the fifth sub-holographic image synthesizer 45, and has a focal length of F3.

[0076] Lasers such as the red laser 15, the green laser 16, and the blue laser 17 emit laser light, which is combined into a beam of laser light by the beam combiner 18. The laser light passes through the shaping mirror 19 to compress the divergence angle and then illuminates the digital galvanometer 27 through the reflecting mirror. The control system 28 of the digital galvanometer 27 realizes the projection of the image by coordinating the scanning of the digital galvanometer 27 and the switching of the lasers. The light carrying the image is projected onto the composite holographic optical element 3. The reflected light on the composite holographic optical element 31 illuminates the three sub-compensation parts of the composite holographic image synthesizer 4 through the scattering screen 32 and the space around it, forming images 61, 62, and 63 with different depths, and is received by the observer's eyes 5.

[0077] Embodiment 4

[0078] See Figure 4 , which is a schematic structural diagram of a multi-depth planar head-up display system in this embodiment. The multi-depth planar head-up display system in this embodiment includes: a light source 1, a projection system 2, a composite holographic compensator 3, and a composite holographic image synthesizer 4. The holographic image synthesizer 4 is attached to the automotive windshield. The light source includes a laser, a color combiner 18, and a shaping mirror 19, where the laser includes a red laser 15, a green laser 16, and a blue laser 17.

[0079] The projection system 2 is a non-focal projection system. The projection system 2 includes a digitally vibratable galvanometer 27 and a control system 28. The control system 28 coordinates the switching of the three-color laser and the vibration of the digital galvanometer 27.

[0080] The described composite holographic compensator 3 includes a composite holographic element 31 and a scattering screen 32. The composite holographic element 31 includes three sub-compensation parts. For the convenience of distinction, the three different sub-compensation parts are respectively a first sub-compensation part 311, a second sub-compensation part 312, and a third sub-compensation part 313. The three sub-compensation parts can compensate for the aberration and speckle of images at three different depths. In the embodiment of the present application, the three sub-compensation parts are located in three different regions of the composite holographic element 31. The scattering screen 32 is placed obliquely so that the inclination angle of the scattering screen 32 with the holographic image synthesizer 4 or the automobile windshield is approximate or the same, so as to improve the scattering effect of the scattering screen 32 on light and better increase the viewing angle of the image.

[0081] In the embodiment of the present application, the composite holographic image synthesizer 4 includes three sub-holographic image synthesizers. For the convenience of distinction, the three sub-holographic image synthesizers are respectively a first sub-holographic image synthesizer 41, a fourth sub-holographic image synthesizer 44, and a fifth sub-holographic image synthesizer 45. The first sub-holographic image synthesizer 41, the fourth sub-holographic image synthesizer 44, and the fifth sub-holographic image synthesizer 45 are all holographic optical lens imaging synthesizers, and their focal lengths are different. The first sub-holographic image synthesizer 41 is a holographic lens, which is composed of a micro-nano structure formed by the interference of a plane wave and a spherical wave stored in the first sub-holographic image synthesizer 41, and the focal length is F1; the fourth sub-holographic image synthesizer 44 is a holographic lens, which is composed of a micro-nano structure formed by the interference of a spherical wave and a spherical wave stored in the fourth sub-holographic image synthesizer 44, and the focal length is F2; the fifth sub-holographic image synthesizer 45 is a holographic lens, which is composed of a micro-nano structure formed by the interference of a spherical wave and a spherical wave stored in the fifth sub-holographic image synthesizer 45, and the focal length is F3. The first sub-holographic image synthesizer 41 is used to form a far image 63, the fourth sub-holographic image synthesizer 44 is used to form a middle image 62, and the fifth sub-holographic image synthesizer 45 is used to form a near image 61.

[0082] The first sub-compensation part 311 in the composite holographic element 31 is a hologram, which is composed of micro-nano scale holographic fringes located inside the first sub-compensation part 311. The holographic fringes are formed by the interference and recording of a reference light and a wavefront encoded with the aberration and dispersion conjugate of the fifth sub-holographic image synthesizer 45 during the imaging process. The second sub-compensation part 312 in the composite holographic element 31 is a hologram, which is composed of micro-nano scale holographic fringes located inside the second sub-compensation part 312. The holographic fringes are formed by the interference and recording of a reference light and a wavefront encoded with the aberration and dispersion conjugate of the fourth sub-holographic image synthesizer 44 during the optical lens imaging process. The third sub-compensation part 313 in the composite holographic element 31 is a phase plate, which is composed of a micro-nano scale surface relief structure. The surface relief structure is encoded with the wavefront information of the aberration and dispersion conjugate of the first sub-holographic image synthesizer 41 during the optical lens imaging process.

[0083] In the embodiment of the present application, the first sub-compensation part 311 compensates for the aberration and speckle of the fifth sub-holographic image synthesizer 45 in the subsequent composite holographic image synthesizer 4. The second sub-compensation part 312 compensates for the aberration and speckle of the fourth sub-holographic image synthesizer 44 in the subsequent composite holographic image synthesizer 4. The third sub-compensation part 313 compensates for the aberration and speckle of the first sub-holographic image synthesizer 41 in the subsequent composite holographic image synthesizer 4. That is, the sub-compensation parts 311, 312, and 313 compensate for the aberration and speckle in different regions corresponding to the sub-holographic image synthesizers 45, 44, and 41 in the subsequent composite holographic image synthesizer 4.

[0084] The red laser 15, green laser 16, and blue laser 17 emit lasers, which are combined into a beam of laser by the beam combiner 18. The laser passes through the shaping mirror 19 to compress the divergence angle and then illuminates the digital galvanometer 27 through a reflecting mirror (not labeled in the figure). The control system 28 of the digital galvanometer 27 realizes the projection of the image by coordinating the scanning of the digital galvanometer 27 and the switching of the red laser 15, green laser 16, and blue laser 17. The light carrying the image is projected onto the composite holographic optical element 3. The reflected light on the composite holographic optical element 31 illuminates the sub-holographic image synthesizers 45, 44, and 41 of the composite holographic image synthesizer 4 through the scattering screen 32 and the surrounding space, forming images 61, 62, and 63 at different depths. And it is received by the observer's eye 5.

[0085] Embodiment 5

[0086] See Figure 5, which is a schematic structural diagram of a multi-depth planar head-up display system in this embodiment. The multi-depth planar head-up display system in this embodiment includes: a light source 1, a projection system 2, a composite holographic compensator 3, and a composite holographic image synthesizer 4. The holographic image synthesizer 4 is attached to the automotive windshield. The light source includes a laser, a color combiner 18, and a shaping mirror 19. The laser includes a red laser 15, a green laser 16, and a blue laser 17.

[0087] The projection system 2 is a afocal projection system. The projection system 2 includes a digitally controllable mirror 27 that can vibrate two-dimensionally and a control system 28. The control system 28 coordinates the switching of the three-color lasers 15, 16, and 17 and the vibration of the two-dimensional mirror 27.

[0088] The composite holographic compensator 3 is composed of a transmissive composite holographic element 33 and a diffuser screen 32. The composite holographic element 33 includes three sub-compensation parts. For the convenience of distinction, in the embodiments of this application, the three sub-compensation parts are the fourth sub-compensation part 331, the fifth sub-compensation part 332, and the sixth sub-compensation part 333 respectively. The three sub-compensation parts compensate for the aberration and speckle of images at different depths respectively. The diffuser screen 32 is placed obliquely.

[0089] The composite holographic image synthesizer 4 is divided into three sub-holographic image synthesizers, all of which are holographic optical lens imaging synthesizers. For the convenience of distinction, the three sub-holographic image synthesizers are the first sub-holographic image synthesizer 41, the fourth sub-holographic image synthesizer 44, and the fifth sub-holographic image synthesizer 45 respectively. The first sub-holographic image synthesizer 41 is a holographic lens, which is composed of a micro-nano structure formed by the interference of a plane wave and a spherical wave stored in the first sub-holographic image synthesizer 41, and the focal length is F1; the fourth sub-holographic image synthesizer 44 is a holographic lens, which is composed of a micro-nano structure formed by the interference of a spherical wave and a spherical wave stored in the fourth sub-holographic image synthesizer 44, and the focal length is F2; the fifth sub-holographic image synthesizer 45 is a holographic lens, which is composed of a micro-nano structure formed by the interference of a spherical wave and a spherical wave stored in the fifth sub-holographic image synthesizer 45, and the focal length is F3. The first sub-holographic image synthesizer 41 is used to form a far image 63, the fourth sub-holographic image synthesizer 44 is used to form a middle image 62, and the fifth sub-holographic image synthesizer 45 is used to form a near image 61.

[0090] The sixth sub-compensation part 333 in the composite holographic element 33 is a hologram, which is composed of micro-nano scale holographic fringes located inside the sixth sub-compensation part 333. The holographic fringes are formed by the interference and recording of a reference light and a wavefront encoded with the aberration and dispersion conjugate to that of the fifth sub-holographic image synthesizer 45 during the imaging process. The fifth sub-compensation part 332 in the composite holographic element 33 is a hologram, which is composed of micro-nano scale holographic fringes located inside the fifth sub-compensation part 332; the holographic fringes are formed by the interference and recording of a reference light and a wavefront encoded with the aberration and dispersion conjugate to that of the fourth sub-holographic image synthesizer 44 during the optical lens imaging process. The fourth sub-compensation part 331 in the composite holographic element 33 is a phase plate, which is composed of a micro-nano scale surface relief structure. The surface relief structure encodes the wavefront information conjugate to the aberration and dispersion of the first sub-holographic image synthesizer 41 during the optical imaging process.

[0091] In the embodiments of the present application, the sub-compensation parts 331, 332 and 333 respectively compensate for the aberration and speckle of different regions corresponding to 45, 44 and 41 in the subsequent composite holographic image synthesizer 4.

[0092] Lasers 15, 16, and 17 emit lasers, which are combined into a single laser beam by a beam combiner 18. The laser beam passes through a shaping mirror 19 to compress the divergence angle and then illuminates a digital galvanometer 27 through a reflecting mirror. The control system 28 of the digital galvanometer 27 realizes the projection of an image by coordinating the scanning of the digital galvanometer 27 and the switching of the lasers 15, 16, and 17. The light beam carrying the image is projected onto the composite holographic optical element 3. The transmitted light on the composite holographic optical element 3 illuminates different sub-holographic image synthesizers of the composite holographic image synthesizer 4 after passing through the scattering screen 32 and the surrounding space, forming images 61, 62 and 63 at different depths. And it is received by the observer's eyes 5.

[0093] In the embodiments of the present application, the composite holographic element 33 includes three sub-compensation parts. In other embodiments, the composite holographic element 33 may also include two sub-compensation parts or more than four sub-compensation parts. The sub-compensation parts are correspondingly arranged with the sub-holographic image synthesizers so as to form images at two or more than four depths.

[0094] Embodiment 6

[0095] See Figure 6 , which is a schematic structural diagram of a multi-depth planar head-up display system in this embodiment. The multi-depth planar head-up display system in this embodiment includes: a light source 1, a projection system 2, a composite holographic compensator 3, and a composite holographic image synthesizer 4. The light source includes a light-emitting diode (LED) 13 and a collimating lens group 14.

[0096] The projection system 2 has a large depth of field projection function. The projection system includes a digital micromirror device 24, a total reflection prism 25, and a large depth of field projection lens 26.

[0097] The composite holographic compensator 3 includes a composite holographic element 31 and a scattering screen 32. The composite holographic element 31 includes two sub-compensation parts. For the convenience of distinction, they are the first sub-compensation part 311 and the second sub-compensation part 312 respectively. The first sub-compensation part 311 and the second sub-compensation part 312 respectively compensate for the aberration, speckle, and chromatic dispersion of images at different depths.

[0098] The composite holographic image synthesizer 4 includes two sub-holographic image synthesizers. For the convenience of distinction, they are the second sub-holographic image synthesizer 42 and the third sub-holographic image synthesizer 43 respectively. Among them, the second sub-holographic image synthesizer 42 has an optical mirror surface function and is a holographic optical mirror reflection synthesizer; the third sub-holographic image synthesizer 43 has an optical scattering imaging function and is a holographic optical scattering imaging synthesizer. The second sub-holographic image synthesizer 42 forms an intermediate image 62 (Middle image), and the third sub-holographic image synthesizer 43 forms a near image 61 (Near image).

[0099] The first sub-compensation part 311 in the composite holographic element 31 is a hologram, which is composed of micro-nano scale holographic fringes located inside the first sub-compensation part 311. The holographic fringes are formed by the interference of a reference light and a wavefront encoded with speckle noise negatively correlated with that formed by the third sub-holographic image synthesizer 43 during the scattering imaging process and recorded. The second sub-compensation part 312 in the composite holographic element 31 is a holographic grating, which is composed of micro-nano scale grating fringes located inside the second sub-compensation part 312. The grating fringes are formed by the interference of a reference light and a wavefront encoded with the conjugate of chromatic dispersion and aberration during the optical mirror surface imaging process of the second sub-holographic image synthesizer 42 and recorded. The different functional regions respectively compensate for the aberration, speckle, or chromatic dispersion of the corresponding different regions in 42 and 43 of the subsequent composite holographic image synthesizer 4.

[0100] The second sub-holographic image synthesizer 42 includes a holographic optical mirror reflection synthesizer. The holographic optical mirror reflection synthesizer is a holographic mirror, which is composed of a micro-nano structure formed by the interference of two plane waves stored in the first sub-holographic image synthesizer 42.

[0101] The holographic optical scattering imaging synthesizer of the third sub-holographic image synthesizer 43 has an optical scattering imaging function. The holographic optical scattering imaging synthesizer is a holographic scattering mirror composed of a micro-nano structure formed by the interference of a scattered wavefront and a plane wave stored in the third sub-holographic image synthesizer 43.

[0102] In an embodiment of the present application, the light emitted by the light-emitting diode (LED) 13 forms a collimated illumination wide beam after passing through the collimating lens group 14. The collimated illumination wide beam enters the projection system 2. The collimated wide beam is first reflected by the total reflection prism 25 to illuminate the digital micromirror device 24. The light is reflected from the digital micromirror device 24, passes through the total reflection prism 25, and then is transformed by the projection lens 26 and projected onto the composite holographic element 31. The reflected light of the composite holographic element 31 illuminates different parts of the composite holographic image synthesizer 4 after passing through the scattering screen 32 and its periphery, forming images 61 and 62 with different depths. And it is received by the observer's eye 5.

[0103] The above is only an implementation manner of the present invention, and does not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A multi-depth plane head-up display system, characterized in that, It includes a light source, a projection system, a composite holographic compensator, and a composite holographic image synthesizer. The light source is used to illuminate the projection system. The projection system is used to edit the original three-dimensional image information to generate image information with more than two depths, and project the image information with more than two depths onto the composite holographic compensator. The composite holographic compensator is used to perform error compensation on the image information with more than two depths respectively, and the error compensation includes one or several of aberration compensation, speckle error compensation, and chromatic dispersion error compensation. The composite holographic image synthesizer is used to receive the light transmitted by the projection system and the composite holographic compensator, and project the image information onto more than two depth planes in three-dimensional space to obtain display images with more than two depths.

2. The multi-depth planar head-up display system according to claim 1, wherein The composite holographic compensator is used to reflect or transmit light and make the light enter the composite holographic image synthesizer.

3. The multi-depth plane head-up display system according to claim 1, wherein The composite holographic compensator includes a composite holographic element, and the composite holographic element includes more than two sub-compensation parts. One sub-compensation part is used to compensate for the error of the wavefront carrying the image information of one depth plane, and the other sub-compensation part is used to compensate for the error of the wavefront carrying the image information of another depth plane. Optionally, the composite holographic element includes one or several of a hologram, a phase plate, and a holographic grating.

4. The multi-depth planar head-up display system according to claim 3, wherein The composite holographic compensator further includes a scattering screen, and the scattering screen is used to receive the light transmitted by the composite holographic element and transmit it to the composite holographic image synthesizer.

5. The multi-depth plane head-up display system according to claim 3, wherein, The composite holographic image synthesizer is divided into more than two sub-holographic image synthesizers. One sub-holographic image synthesizer is used to receive the light transmitted by one sub-compensation part and synthesize a planar display image of one depth; another sub-holographic image synthesizer is used to receive the light transmitted by another sub-compensation part and synthesize a planar display image of another depth.

6. The multi-depth planar head-up display system according to claim 5, wherein, The sub-holographic image synthesizer includes one or several of a holographic optical lens imaging synthesizer, a holographic optical mirror reflection synthesizer, and a holographic optical scattering imaging synthesizer.

7. The multi-depth plane head-up display system according to claim 6, wherein, The more than two sub-holographic image synthesizers include two holographic optical lens imaging synthesizers, and the optical power of one holographic optical lens synthesizer is different from that of the other holographic optical lens synthesizer; or / and, The more than two sub-holographic image synthesizers include a combination of two or more of a holographic optical lens imaging synthesizer, a holographic optical mirror reflection synthesizer, and a holographic optical scattering imaging synthesizer.

8. The multi-depth planar head-up display system according to any one of claims 1-7, characterized in that, The light source includes a coherent light source and / or an incoherent light source; Optionally, the coherent light source includes a solid laser and / or a laser diode; Optionally, the incoherent light source includes an LED and / or a super-radiant tube.

9. The multi-depth plane head-up display system according to any one of claims 1-7, characterized in that, The projection system includes one or several of a projection system with a Fourier transform function, a afocal projection system, and a large depth of field projection system.

10. The multi-depth plane head-up display system according to claim 9, wherein The projection system includes a polarization beam splitter, a liquid crystal on silicon (LCOS) spatial light modulator, and a projection lens. The polarization beam splitter is configured to receive the light from the light source and reflect the light to the LCOS spatial light modulator. The light reflected from the LCOS spatial light modulator passes through the polarization beam splitter, and the light passing through the polarization beam splitter is transformed and projected by the projection lens onto the composite holographic compensator; or, The projection system includes a total reflection prism, a digital micromirror device (DMD), and a projection lens. The light emitted by the light source is reflected by the total reflection prism to the DMD. The light is reflected from the DMD to the total reflection prism and then transmitted to the projection lens. The projection lens transforms and projects the light onto the composite holographic compensator; or, The projection system includes a digital galvanometer with two-dimensional vibration and a control system.

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