Holographic display system for a motor vehicle and motor vehicle

Abstract

Holographic display system (100) for a motor vehicle (106), wherein the holographic display system (100) comprises the following: a light source (126) for generating a coherent beam of light; a spatial light modulator (102), SLM (102) comprising a two-dimensional pixel array (104) with SLM resolution, wherein the two-dimensional pixel array (104) is encoded with holograms to diffract the coherent light and modulate the beam of coherent light to generate a plurality of subframes (130), each of the subframes (130) being associated with one of a plurality of partial viewfields (132); a display area (122) with a multitude of sections (124) and a computer (144) with: a processor (146) connected to the light source (126) and the SLM (102); and a memory (148) containing instructions such that the processor (146) is programmed to control at least the two-dimensional pixel array (104) of the SLM (102) to generate the subframes (130) for displaying a reconstructed image (160) within a full field of view, the full field of view comprising each of the partial fields of view (132); wherein the reconstructed image (160) on the display area (122) has a total image resolution and the total image resolution is higher than the SLM resolution; wherein the processor (146) is further programmed to control the SLM (102) in such a way as to cause the subframes (130) on the sections (124) to oscillate angularly, so that each of the subframes (130) has an enlarged section (158) and the enlarged sections (158) of the subframes (130) overlap each other on the display surface (122), wherein the enlarged sections (158) of the associated subframes (130) have a perceived resolution which is higher than the SLM resolution.

Description

Technical field

[0001] The present disclosure relates to holographic display systems for motor vehicles and in particular to a holographic display system that controls a spatial light modulator to improve the resolution of reconstructed images and to enlarge an associated eyebox. Introduction

[0002] Automakers are continuously working to improve the resolution and eyebox size of augmented reality (AR) head-up displays (HUDs). The eyebox of AR HUDs is the area in which the driver can see the entire display. Modern luxury or premium vehicles may incorporate AR HUDs with spatial light modulators (SLMs), which modulate light according to a fixed resolution or spatial (pixel) pattern. SLMs are typically used to control incoming light in amplitude only, phase only, or a combination thereof. SLMs create images by diffraction or redistribution of light, rather than blocking it with conventional projection systems. SLMs operate in both reflection mode, such as liquid crystal on silicon (LCoS), and transmission mode, such as glass-on-glass. In other examples, the SLMs may be MEMS mirror SLMs or other suitable SLMs.SLMs can offer high-speed phase or amplitude modulation, highly efficient operation, and a user-friendly graphical software interface.

[0003] The conventional solution for increasing the resolution of AR HUDs and enlarging the associated eyebox is to increase the resolution of the SLM (silicon laser module). Based on the performance requirements for the field of view and eyebox, it may be desirable to have an SLM with a resolution higher than 4K to provide adequate resolution for the AR HUD. The use of multiple SLMs has also been proposed to increase the viewing angle and screen size of holographic display systems. However, increasing the SLM resolution and using multiple SLMs can increase the cost, weight, and complexity of the AR HUDs.

[0004] German patent DE 10 2020 105 992 A1 describes a system comprising a laser, a spatial light modulator with a display, and a control unit. The control unit includes a processing circuit configured to control the display of the spatial light modulator in such a way that the image speckles of a projected image reacting to the laser are reduced based on a time-sequential update of a multitude of phase holograms generated in response to an input image received by the control unit.

[0005] US 2020 / 0 183 079 A1 describes a display device, in particular a near-eye display device for a user. The display device comprises at least one illumination device, at least one spatial light modulator, at least one imaging element, at least one light guide, and at least two partially reflective output coupling elements. The at least one illumination device serves to emit sufficiently coherent light. The at least one imaging element serves to image light originating from the at least one light modulator. The at least two partially reflective output coupling elements, which are provided in the at least one light guide, serve to couple the light out of the light guide.

[0006] While existing holographic display systems fulfill their purpose, the object of the invention is to provide a new and improved holographic display system that addresses these problems. Description of the invention

[0007] The invention is defined by the claims.

[0008] According to a first aspect of the invention, a holographic display system for a motor vehicle is provided. The system comprises a light source for generating a beam of coherent light and a spatial light modulator (SLM) comprising a two-dimensional pixel array with an SLM resolution encoded with holograms that diffracts the coherent light. The two-dimensional pixel array modulates the beam of coherent light to generate a plurality of subframes, each of the subframes being associated with one of a plurality of partial fields of view. The system further comprises a display surface with a plurality of sections. The system also includes a computer with a processor connected to the light source and the SLM.The computer further includes a memory containing instructions such that the processor is programmed to control at least the two-dimensional pixel array of the SLM to generate the subframes for displaying a reconstructed image within a complete field of view, the complete field of view encompassing each of the partial fields of view. The reconstructed image has an overall image resolution on the display surface that is higher than the SLM resolution. The processor is further programmed to control the SLM to angularly oscillate the subframes on the sections, such that each subframe has a magnified section, and the magnified sections of the subframes overlap on the display surface, the magnified sections of the associated subframes having a perceived resolution that is higher than the SLM resolution.

[0009] According to a second aspect of the invention, a motor vehicle comprises a body, which defines a passenger compartment, and a plurality of glass panes surrounding the passenger compartment. The glass panes include at least a windshield, a rear window, a sunroof, and a plurality of windows surrounding the passenger compartment. The motor vehicle further comprises a holographic display system according to one of the embodiments described herein, which is connected to the body. According to one embodiment, the display surface is part of the front windshield, the rear windshield, the sunroof, or the windows.

[0010] According to another embodiment, the system also includes a combiner glass located in the passenger cabin, and the display area is part of the combiner glass.

[0011] According to another embodiment, the light source is a LASER and the SLM is a liquid crystal on silicon (LCOS) SLM or a MEMS mirror SLM.

[0012] Further areas of application will become apparent from the present description. It should be understood that the description and specific examples serve only for illustration and are not intended to limit the scope of this disclosure. Brief description of the drawings

[0013] The drawings described here are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. Fig. Figure 1 is a schematic view of an example of a motor vehicle with a holographic display system. Fig. Figure 2 is a schematic view of a passenger compartment of the motor vehicle of Fig. Figure 1 shows an example of the system with a spatial light modulator (SLM) with a partial field of view, an SLM resolution and an SLM eyebox. Fig. Figure 3 is a schematic view of the system of Fig. Figure 2 shows an example of the system for merging the subframes to provide a frame with a full field of view, a higher resolution than the SLM resolution, and a larger eyebox size than the SLM eyebox size. Fig. Figure 4 is a schematic view of the system of Fig. 2, which shows another example of the system for dithering subframes with partial fields of view to obtain a frame with a full field of view and a higher resolution than the SLM resolution. Fig. Figure 5 is a schematic view of a passenger compartment of the motor vehicle made of Fig. 1, which shows another example of a holographic display system. Fig. Figure 6 is a flowchart of an exemplary procedure for operating the holographic display system of Fig. 1. Detailed description

[0014] The following description is merely exemplary and is not intended to limit the present disclosure, application or use.

[0015] The present disclosure describes an example of a motor vehicle with a holographic display system (System) 100. A non-restrictive example of the System includes an augmented reality (AR) head-up display (HUD) that can blend holographic display elements with other display elements or environmental features to make holographic images appear relative to the physical world. As detailed below, the System 100 includes a spatial light modulator (SLM) 102 with a two-dimensional pixel array 104. The two-dimensional pixel array 104 has an associated resolution, eyebox, and pitch, and uses an encoded hologram to generate subframes for associated partial fields of view.The system further includes a computer to control the SLM to display a reconstructed image formed from each of the subframes, with a maximum field of view based on the SLM's pitch. The reconstructed image has a resolution higher than the SLM's resolution and an eyebox size larger than the SLM's eyebox size. As described in a non-restrictive example below, the subframes can be stitched together, with the subframes displayed and / or positioned side-by-side on the display area to form complete frames encompassing the entire field of view. The perceived overall image would be the result of stitching the subframes together to increase the overall resolution. In another example, the subframes are angularly dithered so that portions of the subframes overlap on common sections of the display area.The perceived resolution of the overlapping parts on the common section is higher than the resolution of the SLM. The system can be used as part of any land, sea, or air vehicle. In other, non-restrictive examples, the system can be used as part of a stationary or mobile power plant, a robot, or a platform. For illustration, an application of the system as an integral part of a motor vehicle is described below, without limiting the present disclosure to such an implementation.

[0016] Referring to Fig. 1 includes an example of a motor vehicle 106, a body 108, which has a passenger compartment 110 ( Fig. 2) and a plurality of glass panes 112 surrounding the passenger compartment 110. The glass panes 112 may comprise at least one front windshield 114, a rear windshield 116, a sunroof 118, and a plurality of windows 120 surrounding the passenger compartment 110.

[0017] As in the Fig. 2 and Fig. As best illustrated in Figure 3, the system 100 also includes a display area 122 with a multitude of sections 124 ( Fig. 3) A non-restrictive example of the display area could be an integral part of the front windscreen 114. In other non-restrictive examples, the display area could be part of the rear windscreen 116 ( Fig. 1), the sunroof 118, the windows 120 or other suitable parts of the vehicle 106.

[0018] Referring to Fig. 1: The motor vehicle 106 further comprises a holographic display system 100 (system) connected to the body 108. The system 100 comprises a light source 126 for generating a beam of coherent light or a coded hologram. A non-restrictive example of the light source 126 may include a laser 128. While in Fig. Figure 1 shows a single LASER 128, but the system can also contain two or more LASERS, such as separate red, green and blue LASERS.

[0019] System 100 further comprises the spatial light modulator (SLM) 102 with the two-dimensional pixel array 104 with SLM resolution and an SLM eyebox. The two-dimensional pixel array 104 modulates the beam of coherent light to create a multitude of subframes 130 ( Fig. 3) or to generate input frames, each of the subframes 130 being associated with one of a plurality of partial fields of view 132. In the illustrated, unlimited example, the two-dimensional pixel array 104 can modulate the light beam to generate subframes 130 that are associated with nine partial fields of view, which can be displayed to create a complete field of view. However, it is conceivable that the two-dimensional pixel array could modulate the light beam to generate subframes that are associated with partial fields of view, so that each subframe forms a fraction of the total field of view. The SLM is a fast-switching spatial light modulator (SLM) with high pixel density and a drive circuit that enables a high frame rate.The high refresh rate can be 60 Hz, allowing the SLM to display a sequence of subframes sequentially at a speed at which the human eye does not perceive flicker when viewing the entire field of view. However, it is conceivable that the refresh rate could be higher or lower than 60 Hz. In a non-restrictive example, the two-dimensional pixel array 104 is a two-dimensional liquid crystal on silicon (LCoS) pixel array 104, providing diffractive phase elements to support holographic projection. In other examples, the spatial light modulators could be MEMS shutter displays or DLP DMD arrays. The spatial light modulators can be controlled independently to block, transmit, or reflect various high-resolution beams.

[0020] In the Fig. In the non-restrictive example shown, the LASER 128 can project a laser beam 134 onto the two-dimensional pixel array 104 of the SLM 102, with corresponding diffracted images 136, 138 passing through a Fourier transform lens 140, which performs beam shaping to focus the resulting perceived image on the display surface 122. The diffracted images 136, 138 can result from the LASER beam projected onto the two-dimensional pixel array 104 and change over time into images that are output to the two-dimensional pixel array 104. In other examples, the system may not include the Fourier transform lens.

[0021] As in Fig. As shown in Figure 3, the system 100 also includes a scanner 142 to direct the subframes 130 to one of the associated sections 124 of the display area 122. Non-restrictive examples of the scanner may include a screen scanning system, a view-zone scanning system, and a 360-degree scanning system. It is considered that other examples of the system with other suitable SLMs may not include the scanner, with the direction of the beam being encoded in the holograms of the subframes of an SLM.

[0022] Referring to Fig. 1: The system 100 further comprises a computer 144 with a processor 146, which is connected to the light source 126, the SLM 102, and the scanner 142. The processor 146 can be used to calculate image data in real time, which is to be output on the two-dimensional pixel array 104 of the SLM 102. The processor 146 can include a processing circuit, which may comprise an application-specific integrated circuit (ASIC), an electronic circuit, and a processor (common, dedicated, or as a group). The computer 144 can further include a memory 148, which executes one or more software or firmware programs, a combinational logic circuit, and / or other suitable components that provide the described functionality. The processor 146 can include an input / output interface 150 for communication with various components, such as an input image source 152 and the SLM 102.The input image source 152 can provide subframes representing associated partial fields of view, which are to be projected as holographic images onto the display surface 122. In this non-restrictive example, the processor 146 can use known image processing techniques to determine a phase hologram to be output on the two-dimensional pixel array 104, resulting in the diffracted images 136, 138 that respond to the laser 128 and, upon beam shaping by the Fourier transform lens 140, produce the desired projected subframes 130 on the display surface 122. In other examples, however, the system may not include the Fourier transform lens. For example, if the system 100 is installed in a vehicle, the input image source 152 could be a vehicle control unit to display measurements, logos, information, entertainment content, or other such image-based data.

[0023] The processor 146 can be communicatively connected, for example via the vehicle communication module, to more than one local processor, such as electronic control units (ECUs) or similar devices contained in the vehicle 100 for monitoring and / or controlling various vehicle components. The processor 146 is generally configured to communicate with the vehicle communication module via an internal wired and / or wireless network, such as a bus or similar within the vehicle 106, like a Controller Area Network (CAN) or similar, and / or other wired and / or wireless mechanisms. Through the vehicle communication module, the processor 146 can send messages to and / or receive messages from various devices within the vehicle 106, such as vehicle sensors, actuators, vehicle components, a human-machine interface (HMI), etc.Alternatively or additionally, in cases where the processor comprises a multitude of devices, the vehicle communication network can be used for communication between the devices, which are represented in this disclosure as Computer 144. Furthermore, as mentioned below, various processors and / or vehicle sensors can supply data to Computer 144. Processor 146 can receive and evaluate data from sensors essentially continuously and / or periodically. In addition, object classification or identification procedures can be used, for example, in Processor 146 based on lidar sensor, camera sensor, etc., data to identify lane markings, a type of object (e.g., vehicle, person, rock, pothole, bicycle, motorcycle, etc.), and physical characteristics of objects.

[0024] The Computer 144 further has a memory 148, which contains one or more forms of computer-readable media and stores instructions that can be executed by the Processor 146 to perform various operations, including those disclosed here. The memory 148 contains instructions such that the Processor 146 is programmed to control the two-dimensional pixel array 104 of the SLM 102 to process the subframes 130 ( Fig. 3) to generate for associated partial fields of view. The processor 146 is further programmed to control the scanner 142 to direct the subframes 130 to one of the associated sections 124 of the display area 122 in order to display a reconstructed image within a complete field of view, the complete field of view encompassing each of the partial fields of view. The reconstructed image on the display area 122 has an overall image resolution, and the overall image resolution is higher than the SLM resolution.

[0025] Referring to Fig. In section 3, the processor 146 is programmed to control the scanner 142 to direct the subframes 130 onto the sections 124 of the display area 122, such that the subframes 130 are arranged side by side without overlapping. The processor 146 is further programmed to control the scanner 142 to direct the subframes 130 onto the sections 124, the sections 124 being arranged in a plurality of rows 154 and a plurality of columns 156 on the display area 122. In this example, the overall image resolution is equal to the SLM resolution multiplied by the number of sections displaying the subframes 130. Furthermore, the display area 122 has a field of view of the display area which is equal to the size of the SLM field of view multiplied by the reciprocal of the ratio between the partial field of view of one of the sections and the complete field of view 130.

[0026] Referring to Fig. 4 Another example of the processor 146 can be programmed to control the SLM 102 so that it dithers the subframes 130 angularly on the sections 124, i.e., makes them fluctuate, so that each of the subframes 130 has an enlarged part 158 ​​and the enlarged parts 158 of the subframes 130 overlap each other on the display surface 122.

[0027] The extended sections 158 of the associated subframes 130 have a perceived resolution that is higher than the SLM resolution.

[0028] Referring to Fig. Section 5 describes that another example of a holographic display system 200 is the system 100 of Fig. 2 is similar, with the example having the same components, characterized by the same numbers increased by 100. However, while the system 100 of Fig. 2 the display area 122 in the form of a surface of the windscreen 114 facing the cabin, the system 200 comprises a combination glass 262 which is separate from the windscreen 214 and arranged inside the passenger cabin 210, and the display area 222 is a part of the combination glass 262.

[0029] In Fig. Figure 6 shows a method 300 for operating the holographic display system 100 for the motor vehicle 106. The method 300 begins in block 302 with the light source 126, which generates the beam of coherent light.

[0030] In block 304, processor 146 generates an initial control signal to control the two-dimensional pixel array of the SLM 102 in order to generate the subframes 130. The two-dimensional pixel array 104 of the SLM 102 modulates the beam of coherent light to generate the subframes 130, such that each of the subframes 130 is assigned to one of several partial fields of view, in response to the SLM 102 receiving the initial activation signal from processor 146.

[0031] In block 306, processor 146 generates a second actuation signal that controls scanner 142 to direct the subframes 130 to one of the corresponding sections 124 of the display area 122. Scanner 142 directs the subframes 130 to the corresponding sections 124 of the display area 122 to display the reconstructed image within the full field of view, so that the full field of view includes each of the partial fields of view, in response to the scanner receiving the second actuation signal from processor 146. In a non-restrictive example where the processor is operating in a stitching mode, processor 146 controls scanner 142 to direct the subframes 130 to the sections 124 so that the subframes 130 are arranged side by side without overlapping.In another, non-restrictive example, where the processor activates a dithering mode, the processor 146 controls the scanner 142 to dither the subframes 130 at an angle to the sections 124, so that the subframes 130 overlap.

[0032] In block 308, the reconstructed image 160 is displayed on the display area 122, so that the reconstructed image has a total image resolution that is higher than the SLM resolution, and an eyebox size that is larger than the eyebox size of the SLM 102.

[0033] Computers and computing devices generally contain computer-executable instructions, which can be executed by one or more computing devices, such as those mentioned above. Computer-executable instructions can be compiled or interpreted from computer programs created using a wide variety of programming languages ​​and / or technologies, including, but not limited to, Java, C, C++, MATLAB, Simulink, Stateflow, Visual Basic, Java Script, Perl, HTML, Tenseorflow, Pytorch, Keras, and others, either alone or in combination. Some of these applications can be compiled and executed on a virtual machine, such as the Java Virtual Machine, the Dalvik Virtual Machine, or similar. Generally, a processor (e.g., a microprocessor) receives instructions, for example, from memory, a computer-readable medium, etc., and executes these instructions, thereby running one or more processes, including one or more of the processes described here. Such instructions and other data can be stored and transmitted using a variety of computer-readable media. A file in a data processing system is generally a collection of data stored on a computer-readable medium, such as a storage medium, random-access memory, etc.

[0034] Memory can include a computer-readable medium (also called a processor-readable medium), which contains any non-volatile (e.g., tangible) medium involved in providing data (e.g., instructions) that can be read by a computer (e.g., a computer's processor). Such a medium can take many forms, including, but not limited to, non-volatile and volatile media. Non-volatile media include, for example, optical or magnetic disks and other permanent storage devices. Volatile media include, for example, dynamic random-access memory (DRAM), which typically forms main memory. Such instructions can be transmitted over one or more transmission media, including coaxial cable, copper wire, and fiber optic cable, including the wires that form a system bus connected to a controller's processor.Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, a hard disk, a magnetic tape, any other magnetic medium, a CD-ROM, a DVD, any other optical medium, punched cards, a paper tape, any other physical medium with hole patterns, a RAM, a PROM, an EPROM, a FLASH EEPROM, any other memory chip, or a cassette, or any other medium that a computer can read from.

[0035] Databases, data repositories, or other data storage devices described here can encompass various mechanisms for storing, accessing, and querying different types of data, including a hierarchical database, a set of files in a file system, an application database in a proprietary format, a relational database management system (RDBMS), and so on. Each of these data storage devices is typically contained within a computer device running a computer operating system such as one of those mentioned above, and access is via a network in one or more of the most varied ways. A file system can be accessed from a computer operating system and can contain files stored in various formats.An RDBMS generally uses the Structured Query Language (SQL) in addition to a language for creating, storing, editing and executing stored procedures, such as the PL / SQL language mentioned above.

[0036] In some examples, system elements can be implemented as computer-readable instructions (e.g., software) on one or more computer devices (e.g., servers, personal computers, etc.) stored on associated computer-readable media (e.g., floppy disks, memory, etc.). A computer program product can contain such instructions stored on computer-readable media to perform the functions described here.

[0037] With regard to the media, processes, systems, methods, heuristics, etc. described herein, it should be understood that although the steps of such processes, etc., have been described as proceeding in a certain ordered sequence, such processes with the described steps can be carried out in a different sequence than the one described here.

[0038] Furthermore, certain steps can be performed simultaneously, other steps can be added, or certain steps described herein can be omitted. In other words, the descriptions of methods contained herein serve to illustrate certain embodiments and are in no way to be interpreted as limiting the claims.

Claims

[1] Holographic display system (100) for a motor vehicle (106), wherein the holographic display system (100) comprises the following: a light source (126) for generating a coherent beam of light; a spatial light modulator (102), SLM (102) comprising a two-dimensional pixel array (104) with SLM resolution, wherein the two-dimensional pixel array (104) is encoded with holograms to diffract the coherent light and modulate the beam of coherent light to generate a plurality of subframes (130), each of the subframes (130) being associated with one of a plurality of partial viewfields (132); a display area (122) with a multitude of sections (124) and a computer (144) with: a processor (146) connected to the light source (126) and the SLM (102); and a memory (148) containing instructions such that the processor (146) is programmed to control at least the two-dimensional pixel array (104) of the SLM (102) to generate the subframes (130) for displaying a reconstructed image (160) within a full field of view, the full field of view comprising each of the subfields of view (132); wherein the reconstructed image (160) on the display area (122) has a total image resolution and the total image resolution is higher than the SLM resolution; wherein the processor (146) is further programmed to control the SLM (102) in such a way as to cause the subframes (130) on the sections (124) to oscillate angularly, so that each of the subframes (130) has an enlarged section (158) and the enlarged sections (158) of the subframes (130) overlap each other on the display surface (122), wherein the enlarged sections (158) of the associated subframes (130) have a perceived resolution which is higher than the SLM resolution. [2] Motor vehicle (106), comprising: a body (108) which defines a passenger cabin (110, 210); a plurality of glass panes (112) surrounding the passenger cabin (110, 210), wherein the glass panes (112) comprise at least a front window (114, 214), a rear window (116), a sunroof (118) and a plurality of windows (120) surrounding the passenger cabin (110, 210); and a holographic display system (100) according to claim 1, which is connected to the body (108). [3] Motor vehicle (106) according to claim 2, wherein the display area (122) comprises a part of the windscreen (114, 214), the rear window (116), the sunroof (118) and / or the windows (120). [4] Motor vehicle (106) according to claim 3, wherein the holographic display system (100) further comprises a combination glass (262) arranged in the passenger cabin (110, 210) and the display area (122) is a part of the combination glass (262).

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