Compact head-up display having transmissive holographic deflection unit

Abstract

The invention relates to an imaging system for a driver's compartment, comprising: an optical projection unit which is configured to output image input as image output; a holographic deflection unit which is configured to deflect the image output relative to an output direction of the image output; and a substantially transparent decoupling unit which is configured to decouple the image output deflected by the holographic deflection unit to an eyebox of the imaging system; wherein the imaging system is configured for a working distance between the optical projection unit and the decoupling unit and / or between the decoupling unit and the eyebox of 50 cm or less.

Description

[0001] August 12, 2025 Carl Zeiss Jena GmbH Z175585WO ANE / Mak

[0002] Compact head-up display with transmissive holographic deflection unit

[0003] 1. Technical field

[0004] The present invention relates to imaging systems, driver's cabs with one or more imaging systems and vehicles, in particular aircraft, with a driver's cab with one or more imaging systems.

[0005] 2. State of the art

[0006] Typical designs of imaging systems, such as head-up displays (HUDs) for vehicles, especially aircraft, include two main types: an overhead installation on the cabin ceiling, where the imaging device and projection optics are generally located above the viewer's head; and an installation in or above / behind the glareshield (glareshield installation, as in the case of aircraft). For some applications, such as civil aviation, cabin ceiling installation is the primary option due to spatial constraints.

[0007] The desire for the largest possible field of view (FOV) combined with a certain minimum eyebox size typically results in a high light transmission value. This, coupled with the typically limited space in a cockpit, presents a significant challenge – especially when ceiling mounting is impossible or impractical due to space constraints. In smaller aircraft with cramped cockpits, such as business jets and regional planes, there is often insufficient space above the pilot's head. This problem is typically exacerbated when a second imaging system or HUD for the co-pilot is desired (a so-called dual-HUD configuration). Given these spatially induced difficulties, it is not always possible to simultaneously meet the installation space requirements and image quality demands in such situations.

[0008] The present invention is therefore based on the objective of at least partially improving corresponding imaging systems, driver's cabs and vehicles.

[0009] 3. Summary of the invention

[0010] This task is at least partially solved by the aspects described herein.

[0011] A first aspect of the present invention relates to an imaging system for a driver's cab, wherein the imaging system comprises a projection optic configured to output an image input; a holographic deflection unit configured to deflect the image output relative to an output direction; and a substantially transparent output coupling unit configured to couple the image output deflected by the holographic deflection unit to an eyebox of the imaging system. The imaging system is configured for a working distance between the projection optic and the output coupling unit and / or between the output coupling unit and the eyebox of 50 cm or less, preferably 40 cm or less or 30 cm or less.

[0012] Keeping the working distance between the projection optics, the output unit, and / or the eyebox short offers several advantages: A shorter distance results in a compact and / or lightweight imaging system, which is particularly beneficial in vehicles where space and / or weight are limited. Reducing the size of the imaging system's optical elements can help lower component manufacturing costs or even make economical production possible in the first place. In particular, the cost of optical elements with aspherical or freeform surfaces, which can significantly improve image quality and reduce the overall number of optical elements required, can be reduced by decreasing the required component volume. Furthermore, a shorter distance can help reduce the required apertures of optical elements for a given optical conductivity, thereby minimizing vignetting (i.e., blurring of the image surface).To avoid cropping of the field of view in parts of the eyebox, a more compact system can also be easier to adjust and calibrate, simplifying the manufacturing and maintenance of the imaging system. Therefore, by minimizing the distance between the projection optics, the output unit, and / or the eyebox, a more efficient, user-friendly, and higher-quality imaging system can be achieved.

[0013] However, conventional imaging systems have not been able to exploit these advantages to date, as the corresponding relative positioning of the projection optics, the output unit, and / or the eyebox was not possible due to space constraints. Specifically, this would require deflecting the image output emitted by the projection optics. However, especially at typical deflection angles, any reflective optics used for deflection would have to be so large that they would exacerbate the existing space problem in confined installation situations, such as in aircraft cockpits. The same applies to an alternative tilted arrangement of the projection optics, so that the image output is directed straight to the output unit of the imaging system. Deflection using transmissive, refractive elements would require bulky and heavy prisms to achieve relevant deflection angles, which would contradict the goal of a compact imaging system.The inventors of the present invention have now succeeded in resolving this conflict by using a holographic deflection unit for deflection, which can achieve high image quality in a very small volume. Thus, both the installation space and image quality requirements can be met simultaneously.

[0014] A second aspect of the present invention relates to an imaging system for a driver's cab, wherein the imaging system comprises a projection optic configured to output an image input as an image output. Furthermore, the imaging system comprises a holographic deflection unit configured to deflect the image output relative to an output direction; and a substantially transparent output coupling unit configured to couple the image output deflected by the holographic deflection unit to an eyebox of the imaging system.

[0015] For the output image, the deflected image, and the extracted image, a propagation direction can be defined for each. This direction can, for example, pass through the geometric centroid of at least the beam cross-section at at least two positions along the propagation direction of the image information, or it can essentially correspond to the propagation direction of the skin ray of the central field point. According to the second aspect, the propagation directions defined in this way for the output image, the deflected image, and the extracted image are not necessarily coplanar. In some examples, the output direction of the image can be at a non-zero angle, e.g., 3°. 0 or more, or out of 5 0 or more to a plane spanned by a direction of the redirected image output and a direction of the decoupled image output.

[0016] In contrast, conventional systems are based on symmetrical beam paths where the propagation directions lie coplanarly in a vertically oriented plane of symmetry, as is the case, for example, with the conventional mounting of the projection optics in the glareshield or above the pilot's head in the driver's cab. This symmetry, which in the prior art was maintained with corresponding installation space requirements, was circumvented by the inventors in that the holographic deflection unit can deflect the image information efficiently and without significantly impairing the achievable image quality. The ability to eliminate the coplanarity of the propagation directions opens up a new degree of freedom, making it possible to utilize the limited space in a driver's cab even more efficiently.

[0017] It is emphasized that the aspects described herein are primarily aimed at applications in imaging systems for driver cabins, particularly in aircraft, but are not limited to this application. They can also be applied to imaging systems for other applications, especially those with tight installation space requirements. The first and second aspects allow for the achievement of the largest possible field of view (FOV) (e.g., a horizontal FOV of 20° or more) in conjunction with a certain minimum eyebox size. These requirements typically result in a high light transmission coefficient, which limits both the minimum volume of the projection optics and the maximum distance between the projection optics and the output unit. The design of the imaging system with the holographic deflection unit described herein makes it possible to resolve this highly complex installation situation even under space constraints.

[0018] In one exemplary embodiment, the imaging system can be configured for a working distance of 50 cm or less between the projection optics and the output unit and / or between the output unit and the eyebox. This is particularly advantageous for the aerospace industry.

[0019] These short working distances can be achieved through the efficient use of the limited space in the driver's cab as described herein, for example, if the propagation directions of the output image, the deflected image, and the decoupled image do not lie in one plane and / or each have significant angles to each other.

[0020] Another aspect that can acquire independent significance is that, in some embodiments, the plane spanned by the direction of the deflected image output and the direction of the coupled-out image output is tilted relative to a vertical plane running in the direction of travel, e.g., by at least 10°, at least 20°, or at least 30°. According to this aspect, the output direction of the image output can be coplanar to the plane or at a non-zero angle to this plane (as described herein). Furthermore, according to this aspect, an imaging system can be configured for a working distance of 50 cm or less between the projection optics and the coupling unit and / or between the coupling unit and the eyebox.By tilting the plane from the vertical plane running in the direction of travel, an additional degree of freedom can be provided, which can be used to optimize the imaging system, especially for compact installation spaces. The image input can be provided in an image plane. In other examples, the image input can be provided in a non-planar, e.g., curved, surface. It is emphasized that the image output from the projection optics and / or the image output deflected by the deflection unit does not necessarily have to be a final image. Rather, these image outputs can each only comprise an intermediate image, with the final image only resulting from the interaction of the projection optics, deflection unit, and / or output unit. This is because, as described herein, the output unit and / or the deflection unit can also have an imaging function, e.g.,The system may be equipped with refractive power and / or wavefront-correcting properties. For example, image errors, such as aberrations, which may be introduced by one of these three elements, can be corrected using the projection optics, the deflection unit, and / or the output unit. In some examples, the system consisting of the deflection unit and the output unit may have a combined refractive power in the range of 2 to 8 diopters. This can be provided, for example, by a curvature of the output unit and / or one or more holograms of the output unit and / or the deflection unit.

[0021] The projection optics can, for example, comprise a system with one or more lenses and / or one or more mirrors. The projection optics can be used, for example, to provide and / or shape the image generated by the imaging system. The projection optics can capture, magnify, align, etc., the images generated by an imaging device. A deflection unit then deflects the image to the output coupling unit. The projection optics can have an optical axis in the form of a straight line that passes through the center of all optical elements, or at least some or more of the optical elements of the projection optics, such as lenses and / or mirrors. The optical components of the projection optics can, for example, be arranged substantially along the optical axis, symmetrically around it. The optical axis can serve as a reference for aligning and / or adjusting the projection optics.

[0022] The optical axis can be the axis of symmetry of the projection optics, along which the optical elements such as lenses and / or mirrors can be aligned. Furthermore, in addition to components arranged symmetrically to the optical axis, the projection optics can also include tilted, decentered, and / or wedge-shaped elements. Besides planar and spherical surfaces, the components can also have aspherical or freeform surfaces.

[0023] The task of the projection unit, in conjunction with the deflection unit and the coupling unit, is to minimize aberration across the field of view and the eyebox so that the projected image is finally clearly and sharply visible in the eyebox.

[0024] The projection optics and the deflection unit can differ in that the components of the projection optics essentially guide light along an optical axis, which may correspond to the output direction of the projection optics, while the deflection unit deflects the image output relative to an output direction (i.e., along the optical axis) of the image output.

[0025] The main advantages of the (e.g., transmissive) holographic deflection unit compared to alternative technical solutions are a significantly smaller area or volume than a deflection mirror with the same function and a considerably smaller volume and weight compared to a deflection prism.

[0026] In another configuration, it would also be conceivable that the deflection unit could include a (not necessarily holographic) reflective or transmissive deflection unit instead of or in addition to a holographic deflection unit.

[0027] The output unit can comprise a (semi-transparent) mirror, a hologram, and / or a special surface that receives the image generated by the projection optics and redirects it so that it becomes visible to the viewer. In addition to redirecting properties, the output unit can also have imaging and / or wavefront-correcting optical properties, so that the final projected image in the eyebox is formed by the interaction of the output unit, the projection optics, and, if applicable, the redirection unit. The output unit can, for example, be equipped with a wavelength-selective coating. The output unit can, for example, reflect the projected image (usually green) or selected wavelengths and / or output them in another way. The output unit can, for example, be transparent to the rest of the spectrum. This allows the projected virtual image and the real image of the outside world to be superimposed when looking through the output unit.This allows information such as flight attitude and path, image data from external sensors (EFVS, enhanced flight vision system), and / or information like speed, altitude, navigation instructions, and / or warning signals to be projected into the pilot's field of vision, for example, so that these (or other displays) appear to float in the distance. The pilot can take in this information without having to look away to view a display on the instrument panel. The projected information is typically displayed in conformity with (i.e., correctly scaled and aligned) the real world. The projection unit can be integrated into a windshield or other cockpit window, or it can be a separate element, such as a visor.

[0028] The eyebox can describe the area within which the driver or user can move their head while still seeing a clear and at least partial image of the imaging system in or through the output unit. The eyebox can define the space in which the viewer's eyes must be positioned to see the projected image substantially correctly. The distances to the eyebox specified herein may refer to distances from the center of the eyebox. A larger eyebox allows more freedom of movement for the user's head without the image becoming distorted or falling outside the field of vision. A "correct" view of the projected image may be defined herein by at least one of the following features:

[0029] Sharpness and clarity: The projected image should be sharp and clear, without blurring or distortion. This means that the optical elements of the system must be correctly aligned and calibrated. Minimum and / or maximum values ​​for sharpness and / or clarity can be determined using conventional metrics (e.g., Modulation Transfer Function, Point Spread Function, Strehl Ratio, Root Mean Square Wavefront Error, Contrast Transfer Function, and / or Edge Spread Function).

[0030] Color fidelity: The colors of the projected image, provided the projected image is not monochromatic, should be true to life and consistent, without color distortion or shifts. An image can be considered color-accurate if spectral shifts of 10 nm or less occur across the eyebox and / or field of view.

[0031] Contrast: A high contrast between the projected image and the background brightness of a projected dark image is important to ensure the legibility and visibility of the information. For example, a contrast ratio of at least 1:50 can be considered sufficiently high to guarantee good visibility and legibility of the projected information.

[0032] Brightness: The projected image should be sufficiently bright to be clearly visible against the real world even under varying lighting conditions, such as daylight. Sufficient brightness can be achieved at 10,000 cd / m². 2 or more.

[0033] Geometric accuracy / freedom from distortion: The projected image should be free of geometric distortion. Lines and shapes should be displayed correctly and proportionally. Sufficient geometric accuracy can be achieved, for example, by a deviation of 10% or less, preferably 5% or less, between the actual image coordinates ((x', y')) and the ideal image coordinates ((x, y)), expressed, for example, as max(\x — x'\ / x , |y — y'\ / y ■ 100%). Electronic pre-distortion of the projected image can be used to improve geometric accuracy.

[0034] Parallax-free: The projected image should appear as if it were in the real world, without parallax errors. This means that the image remains in the correct position regardless of the viewer's head position. Binocular parallax-free: The horizontal and vertical deviations between the directions of a field point perceived by the right and left eye should not exceed 10-15 arcminutes to avoid strain and discomfort when viewing the projected image with both eyes.

[0035] Taking these factors into account ensures a correct view of the projected image in the eyebox, leading to a better user experience and / or higher efficiency of the imaging system.

[0036] In an exemplary embodiment, the holographic redirection unit can comprise a first hologram and a second hologram. The first hologram can be configured to redirect the image output to the second hologram. The second hologram can be configured to redirect the image output to the output coupling unit.

[0037] A corresponding exemplary deflection unit is described herein with reference to Fig. 2. The use of two holograms can achieve a particularly efficient deflection.

[0038] For example, the first and second holograms can comprise a reflection hologram, preferably a reflection relief hologram and / or a reflection volume hologram. Reflection holograms can offer higher efficiency and / or a wider acceptance angle than, for example, transmission holograms, because they reflect light in a way that is efficient over a larger angular range. With the design of the first and second holograms described herein, the deflection unit (as described, for example, with reference to Fig. 2) as a whole can have a transmissive effect, leading to optimization in terms of installation space, while still allowing the advantages of using reflection holograms described herein to be exploited.

[0039] For example, the average distance between the first and second holograms can be 20 mm or less, preferably 10 mm or less, or 1 mm or less. This allows for significant space savings, resulting in a more material- and cost-efficient imaging system and meeting the space requirements in confined installation situations.

[0040] In an exemplary embodiment, the deflection unit can have an interaction surface which can be configured to interact with the image output, wherein the area of ​​the interaction surface can be 145% or less, preferably 120% or less, of a beam cross-section of the image output.

[0041] The interaction surface of the deflection unit can be defined as the portion of the surface onto which the output image from the imaging system strikes. In other words, this is the part of the surface illuminated by the output image. The deflection unit therefore requires a corresponding free aperture. Essentially, an optimal orientation of the deflection unit's surface between the output direction and the deflected direction can minimize the installation space required by the deflection unit. In some examples, the deflection unit can preferably be positioned symmetrically between the output direction and the deflected direction. This can minimize the deflection unit's aperture.

[0042] For example, the projection optics can have an optical axis that is essentially parallel (e.g., with deviations of ± 20°) to a direction of travel of the driver's cabin. It can also have a deviation of at least 5°. 0, or at least 10° should be provided.

[0043] This orientation can be particularly useful for mounting the projector in a way that is especially advantageous for getting in and out of the vehicle, as well as for the driver, pilot, or other user. Furthermore, arranging the projection optics along the direction of travel reduces the lateral installation space required, thus enabling a dual-HUD configuration, i.e., the integration of two imaging systems—one for the pilot and one for the co-pilot. In an example imaging system, the overall deflection of the image output from the projection optics to the eyebox can achieve a total angle of 150° to 210°. 0 , preferably from 160° to 200° or from 170° to 190°.

[0044] The total angle CXG can, for example, be calculated from normalized vectors pointing in the direction of the image output from the projection optics. P or in the direction of the image output coupled out by the coupling unit eA show: a G = arccos (e P ■ e A ~) with the scalar product For two vectors e P and e A , which point in exactly opposite directions, results in: a G = 180°. Total angles in the aforementioned areas can lead to particularly space-saving designs with high image quality. If, for example, the optical axis of the projection optics is arranged in the direction of travel, a total deflection of 180° results in the extracted image output pointing against the direction of travel (i.e., parallel to the typical viewing direction of a driver, pilot, or user). However, in some designs, it can be advantageous to slightly reduce the total deflection by 180°. 0 to deviate, and to use this angular deviation as a further degree of freedom for optimization, e.g. compactification by taking into account inclined and curved surfaces in the vehicle cabin.

[0045] In an exemplary imaging system, the total deflection of the image output from an imaging device to the eyebox can have a total angle of 150° to 210°. 0 preferably from 160° to 200° or from 170° to 190°. The corresponding overall angle can be defined analogously to the above description (e.g., based on a normalized vector in the direction of the image output from the imaging device). B instead of the vector e P .

[0046] For example, the projection optics can be offset perpendicular to the direction of movement relative to the eyebox and / or the projection optics can be positioned at the same height as the eyebox or above it.

[0047] Assuming a right-handed coordinate system with its origin at the center of the eyebox, the x-axis opposite to the direction of movement, and the z-axis along the vertical direction, the displacement perpendicular to the direction of movement can define such that the point where the longitudinal axis of the projection optics (e.g., output direction) intersects the YZ plane lies within the projection optics and can be offset from the center of the eyebox in both the y- and z-directions. For example, the displacement in the z- and / or y-direction can be approximately 10–30 cm or 20–30 cm. The point of intersection can be located near the exit aperture of the projection optics, such that the exit aperture of the projection optics is approximately at the level of the eyebox in the direction of movement. Particularly preferably, the distance of the point of intersection from the exit aperture of the projection optics can be less than 20 cm, e.g., 5–15 cm.

[0048] Examples of such arrangements are shown, for example, in Fig. ic.

[0049] However, it is also possible that the projection optics may be offset from the eyebox in the direction of movement.

[0050] The holographic deflection unit can, for example, be configured to deflect the image output relative to the output direction at an angle of 20° or more, preferably more than 40° or more than 60°. This allows for a particularly favorable positioning of the projection optics, the deflection unit, and the output coupling unit relative to the eyebox.

[0051] Furthermore, it can be advantageous for the angle between the deflected image output and the extracted image output to be 20° or more, 40° or more, or 60° or more.

[0052] In particular, a double (significant) deflection by means of a deflection unit and a coupling unit makes it possible to laterally offset the projection optics and align them favorably from a space-saving perspective. It is emphasized that such a double significant deflection also has independent significance, without necessarily requiring the small working distance and / or the non-coplanarity of the first or second aspect.

[0053] The output unit can, for example, be configured to generate a virtual image for a viewer within the eyebox. The distance of the image plane of the virtual image from the center of the eyebox can be at least 15 m, preferably more than 30 m.

[0054] The virtual image can have a field of view (FOV) with a horizontal opening angle of 20° or more and / or a vertical opening angle of 15°. 0 or include more.

[0055] A large field of view (FV) can allow the user to see more information simultaneously. This is particularly useful in aviation applications, where a variety of information can be displayed in the user's field of view, thereby improving situational awareness.

[0056] A large field of view (FOV) allows for a more realistic and immersive presentation of content, as it better covers the user's field of vision. This is particularly beneficial for enhanced vision and synthetic vision applications, where a larger FOV provides more environmental context and can improve situational awareness.

[0057] In an exemplary embodiment, the decoupling unit can, in a first state, be positioned at least partially on a line of sight between a window of the driver's cabin and the eyebox.

[0058] Furthermore, the output unit can be positioned in a second state outside the line of sight, and the imaging system can also include a means of switching between the first and second states.

[0059] This allows the decoupling unit to be switched to the first (e.g., active) position when needed and to the second (e.g., passive) position when not required, which is particularly advantageous. This can improve safety and user comfort by ensuring the decoupling unit does not obstruct the driver's view when not in use. The switching mechanism can, for example, include a device for moving and / or tilting the decoupling unit relative to the driver's cab. This device can be attached to another element of the driver's cab (e.g., the floor, ceiling, glareshield, etc.).

[0060] For example, the output unit can comprise an essentially transparent and spherically curved plane. In other examples, a planar or aspherically curved plane is also possible.

[0061] This allows the user's field of view to be covered by the output unit in a particularly space- and material-saving manner, while simultaneously providing refractive power, which can improve image quality. For example, to enable a large field of view, it is advantageous for the output unit to have optical refractive power and imaging properties.

[0062] For example, the output unit may have an optical refractive power and / or include a hologram that can be configured to output the image from the holographic deflection unit to an eyebox. Similarly, the projection optics and / or the deflection unit may have a refractive power. The projection optics, the deflection unit, and / or the output unit may be coordinated in their refractive power and / or the exposure of any holograms they may contain.

[0063] For example, the optically effective surface of the output unit can have a spherically curved surface, optionally with an additional hologram. The refractive power provided by the output unit allows for an increase in the field of view (FOV) for a given volume of the rest of the projection optics. Furthermore, the design of the hologram's phase function allows for the correction of aberrations. When using a suitable hologram, the hologram can be exposed with aberrated wavefronts to correct aberrations and thus improve image quality. The reflective surface of the output unit can, for example, be embedded between planar surfaces and / or have a spectrally selective reflectance layer. In a technical implementation, the hologram of the output unit can be designed as a volume hologram.In an alternative implementation, the hologram of the output unit can be designed as a relief hologram, e.g., with a spectrally selective dielectric coating. The phase function of the hologram of the output unit can either be defined by the interference of plane or spherical waves, or alternatively correspond to a free-form phase function, which can be determined by a complex holographic exposure setup.

[0064] For example, the eyebox can have a volume of 100 cm³ 3 or more, preferably 250 cm 3 or more, especially 390 cm 3 or more. For example, the eyebox can have a height and / or width of 5 cm or more. A depth of 7.5 cm or more is possible.

[0065] A large eyebox is desirable because it allows the user a greater range of motion while keeping the display visible. Providing a large eyebox for a wide field of view (FOV) with minimized vignetting is made possible primarily by the reduced working distance between the projection optics and the output unit. Particularly in the aerospace industry, a significantly larger eyebox may be necessary than, for example, in the automotive sector.

[0066] The imaging system may, for example, further include an imaging device configured to provide an image input to the projection optics. To improve image quality, the image input plane may be tilted, rotated, and / or shifted relative to the axis of the projection optics (e.g., the output direction), which can be used to optimize the imaging system as a whole.

[0067] In some examples, the imaging means may include, for example, means for laser projection onto a diffuser in the image plane, and / or a DMD, LCD, (O)LED, and / or Micro(O)LED display in the image plane or mapped onto a diffuser in the image plane. The imaging means or imaging system may include, for example, a light or radiation source to generate light or radiation. The projection optics may include optics (e.g., one or more lenses, mirrors or reflective surfaces, filters, and / or apertures) to direct and / or focus the light or radiation from the light or radiation source to the deflection unit. In some implementations, the imaging system may include a data processor and a storage medium. The data processor in the imaging system may, for example, be configured to control the imaging means to display a time-varying representation of the imaging system—e.g.,at least partially based on one or more external factors, such as the position and / or movement of the (air)craft. The storage medium can, for example, store relevant data, information, logs, and / or computer programs. In some implementations, the mapping system may include one or more computers containing one or more data processors configured to execute one or more programs containing a variety of instructions according to the principles described above. Each data processor may contain one or more processor cores, and each processor core may include logic circuits for data processing. For example, a data processor may include an arithmetic logic unit (ALU), a control unit, and various registers. Each data processor may include a cache memory.Each data processor can comprise a system-on-a-chip (SoC) containing multiple processor cores, random access memory (RAM), graphics processors, one or more controllers, and one or more communication modules. Each data processor can contain millions or billions of transistors.

[0068] The data processing described in this document, such as controlling the display of the imaging system, can be performed using one or more computers containing one or more data processors for data processing, one or more storage media for data storage, and / or one or more computer programs containing instructions that, when executed by the one or more computers, cause the processes to be carried out. The one or more computers may include one or more input devices, such as a keyboard, a mouse, a touchpad, and / or a voice command module, as well as one or more output devices, such as a display and / or a speaker.

[0069] In some implementations, the one or more computing devices may comprise digital electronic circuits, computer hardware, firmware, software, or a combination thereof. The data processing features may be implemented in a computer program product materially embodied in an information carrier, such as a machine-readable storage medium, for execution by a programmable processor; and procedural steps may be executed by a programmable processor that executes a program of instructions to fulfill the functions of the described implementations. Alternatively or additionally, the program instructions may be encoded in a propagated signal, which is an artificially generated signal, such as a signal from a computer.A machine-generated electrical, optical or electromagnetic signal that is produced to encode information for transmission to a suitable receiving device to be executed by a programmable processor.

[0070] A computer program can be written in any form of a programming language, including compiled or interpreted languages, and it can be provided in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computer environment.

[0071] For example, one or more computers can be configured to run a computer program, and they can include general-purpose and specialized microprocessors, as well as any processor of any type of digital computer. Generally, a processor receives instructions and data from read-only memory, random-access memory, or both. Elements of a computer system include one or more processors for executing instructions and one or more storage devices for storing instructions and data. Generally, a computer system also includes, or is operationally coupled to, a device for receiving or transmitting data from one or more machine-readable storage media, or both, such as hard disks, magnetic disks, solid-state drives, magneto-optical disks, or optical disks.Machine-readable storage media suitable for embodying computer program instructions and data include various forms of non-volatile memory, including, for example, semiconductor storage devices such as EPROM, EEPROM, flash memory devices and solid-state drives; magnetic disks such as internal hard disks or removable disks; magneto-optical disks; and CD-ROM, DVD-ROM and / or Blu-ray discs.

[0072] In some implementations, the processes described above can be performed using software running on one or more mobile computing devices, one or more local computing devices, and / or one or more remote computing devices (which may be, for example, cloud computing devices).For example, software procedures consist of one or more computer programs that are executed on one or more programmed or programmable computer systems, either on mobile computing devices, local computing devices or remote computing systems (which may include various architectures such as distributed systems, client / server systems, grid systems or cloud systems), each comprising at least one processor, at least one data storage system (including volatile and non-volatile memory and / or storage elements), at least one wired or wireless input device or port and at least one wired or wireless output device or port.

[0073] In some implementations, the software can be provided on a medium, such as a CD-ROM, DVD-ROM, Blu-ray Disc, solid-state drive, or hard disk, that can be read by a general-purpose or dedicated programmable computer, or it can be transmitted over a network (encoded in a propagated signal) to the computer where it is executed. The functions can be performed on a dedicated computer or using dedicated hardware, such as coprocessors. The software can be implemented in a distributed manner, with different parts of the computations specified by the software being performed by different computers. Each such computer program is preferably stored on a storage medium or device (e.g., a USB drive).The system according to the invention can also be considered a computer-readable storage medium configured with a computer program, wherein the storage medium so configured causes the computer system to perform the functions described herein in a specific and predefined manner.

[0074] A third aspect of the present invention relates to a driver's cab with one or more imaging systems as described herein.

[0075] A fourth aspect of the present invention relates to a vehicle with a driver's cab (or several driver's cabs), each with one or more imaging systems as described herein. The vehicle may, for example, be a road vehicle such as a passenger car, a commercial vehicle (e.g., a truck, van, semi-trailer truck, construction vehicle, bus, etc.), a two-wheeler (e.g., a motorcycle, scooter, moped, bicycle (including e-bikes), etc.), a rail vehicle (e.g., a passenger train, freight train, tram, subway, etc.), a watercraft (e.g., a ship, sailboat, motorboat, etc.), an aircraft (e.g., a passenger aircraft, cargo aircraft, light aircraft, sports aircraft, helicopter, spacecraft, etc.), and / or a special-purpose vehicle (e.g., an agricultural vehicle, construction machine, rescue vehicle, military vehicle, etc.).

[0076] Corresponding driver cabins and vehicles essentially exhibit the advantages described herein with regard to imaging systems.

[0077] The embodiments of the present invention described herein, and the optional features and properties mentioned in this regard, should also be understood as being disclosed in all combinations with one another. In particular, in the present case, the description of a feature encompassed by an embodiment should not be understood—unless expressly stated otherwise—to mean that the feature is essential or indispensable for the function of the embodiment.

[0078] 4. Description of the figures

[0079] Fig. ta shows a left-hand view of an exemplary imaging system for a driver's cab.

[0080] Fig. ib shows a top view of an exemplary imaging system for a driver's cab.

[0081] Fig. ic shows a view of an exemplary imaging system for a driver's cab from the rear, from the left and from above in relation to an exemplary seating position of a user.

[0082] Fig. 2 shows an exemplary deflection unit of an exemplary imaging system.

[0083] 5. Detailed description of preferred embodiments

[0084] Fig. a1a shows a left-hand view of an exemplary imaging system 1 for a driver's cab.

[0085] Fig. ib shows a top view of an exemplary imaging system 1 for a driver's cab.

[0086] The imaging system 1 of the views from Figs. a1a and b1b comprises an image plane 10, a projection optic 20, a holographic deflection unit 30, an output coupling unit 40, an exit pupil 50 and an eyebox 60. The exit pupil 50 is designed such that the projected virtual image is perceptible within the volume of the eyebox 60.

[0087] The projection optics 20 can comprise one or more optical elements, such as one or more lenses and / or one or more mirrors. The deflection unit 30 can, as described herein, comprise, for example, two reflection holograms (e.g., as shown in Fig. 2). The output unit 40 can, for example, comprise a transparent sight and / or a transparent disc, such as a sight and / or a corresponding disc that can be pivoted and / or moved between a first and second state as described herein, and / or be integrated into a windshield. Furthermore, the output unit 40 can be reflective for light that can be provided, for example, by an imaging device (not shown) in the image plane 10.

[0088] Figures ta and ib show that the projection optics 20 outputs the image approximately in the direction of movement (along the x-axis, from right to left). In the example shown in Figures 1a and ib, the projection optics 20 is also offset perpendicular to the direction of movement relative to the eyebox 60 (specifically along the y-axis, i.e., horizontally offset). Furthermore, the projection optics 20 is positioned slightly above the eyebox 60 along a vertical axis (z-axis). There is no significant displacement of the projection optics 20 along the direction of movement in the illustrated example. The projection optics 20 is essentially positioned at the same location along the direction of movement as the eyebox.

[0089] Figures ta and ib show, by way of example, the first working distance di between the projection optics 20 and the output unit 40, and the second working distance d2 between the output unit 40 and the eyebox 60. It is schematically illustrated that the working distance(s) described herein can be defined by the distance traveled by the image output between the components along its propagation direction. This path can be a straight line (as shown for d2), but does not have to be (as shown for di). In the example shown in Figures 1a and ib, the first working distance di between the projection optics 20 and the output unit 40 is approximately 30 cm, and the second working distance d2 between the output unit 40 and the eyebox 60 is approximately 25 cm. In other examples, distances in the range of 15 cm to 50 cm or 20 cm to 40 cm can be used.

[0090] In the example shown, the two vectors e P and e A They point in approximately opposite directions, and are therefore approximately antiparallel. The directions of the vectors are highlighted by dashed lines in Fig. ic (left view). However, they are not exactly antiparallel, but rather form an angle of approximately a. G “170°. The projections of the vectors in a horizontal plane are essentially parallel (as shown in Fig. ic, top view). As can be seen in Fig. ic (left view), the vector e A arranged almost in the horizontal plane (typically the viewing direction is slightly downwards, e.g. by 2° to 8° or approx. 5°), the vector e P However, it spans an angle of approximately 15°. 0 to the horizontal plane, which can also lie, for example, in the range of 10° to 20°. In other examples, a GFor example, as described herein, the angle can be selected within the range of 150° to 210°. The inventors recognized that it can be advantageous not to guide the beam path in a single plane, but rather to utilize the angular deviation from a plane as an additional degree of freedom.

[0091] In the example shown, due to the aforementioned angular deviation, the output direction is at an angle of 5°. 0or more precisely, the plane spanned by the direction of the deflected image output and the direction of the extracted image output. For illustration, the intersection line of this plane with the drawing plane is shown as a dashed line in Fig. ic (rear view). The angle is defined as the (acute) angle formed by the output direction and the plane. As can be seen in Fig. 1a (rear view), the direction of the projection optics 20 forms an angle relative to this plane. In the example shown, this angle is approximately 10°, but in other examples it can also be other values ​​in the range of 3. 0 and exhibit more, e.g. in the range of 5 0 up to 10°. However, it is also possible that the output direction is essentially coplanar to the aforementioned plane. This is because the tilting of the plane away from the vertical plane of symmetry (in Fig. ic by approximately 45°) already results in a certain degree of symmetry. 0) another degree of freedom can be provided for optimization.

[0092] Fig. ic shows a view of an exemplary imaging system 1 for a driver's cab from the rear, from the left, and from above in relation to an exemplary seating position of a user 2 (e.g., a pilot of an aircraft such as an airplane and / or helicopter). Essentially, Fig. ic shows the imaging system i of Figs. 1a and 1b, with the additional rear view and the depiction of the user 2 illustrating how the imaging system can be positioned in a particularly space-saving manner close to the user 2 but still outside their typical range of motion.

[0093] In some examples, the projection optics and the holographic deflection unit can follow each other along the optical path of an exemplary imaging system (e.g., imaging system 1) in the beam direction. For example, in some examples, no further element may be positioned between the projection optics and the holographic deflection unit. Similarly, the output coupling unit and the eyebox may follow each other along the optical path in the beam direction. For example, in some examples, no further element may be positioned between the output coupling optics and the eyebox.

[0094] Fig. 2 shows an exemplary deflection unit 30 of an exemplary imaging system (as shown, for example, in Figs. 1a-1ic).

[0095] The operation of the (transmissive) holographic deflection unit 30 is illustrated in Fig. 2. The holographic deflection unit 30 of Fig. 2 comprises two mutually facing reflective holograms or holographic optical elements (HOEs) 31, 32, which are positioned a short distance apart. The distance is typically 20 mm or less, preferably 10 mm or less, and in particular 1 mm or less. The holograms 31, 32 can be wavelength- and angle-selective, so that the incident beam 33 (hereinafter referred to as the image output from the projection optics) can pass through the first hologram 31 (undisturbed) at the projection wavelength, preferably in the green spectral range around 530 nm, and is deflected back by the second hologram 32 towards the first hologram 31. The deflected beam 34 now hits the first hologram 31 at a different angle and is reflected back by it and deflected or refracted again.Overall, the outgoing beam 35 (referred to here as the image output deflected by the deflection unit 30) is deflected relative to the incoming beam 33 in the transmission direction. Compared to a monolithic transmission hologram, the solution consisting of two reflection holograms has the advantage of supporting a larger angular range. Furthermore, this provides more degrees of freedom for image manipulation (e.g., refractive power, wavefront manipulation).

[0096] In a technical implementation, the two holograms 31, 32 can either be applied to the opposite outer surfaces of a common substrate (not shown). Alternatively, the holograms 31, 32 can be applied to the facing sides of two substrates that are connected to each other.

[0097] Furthermore, the holograms 31, 32 can be encapsulated in other ways, for example as a stack of foils between two substrates. Regardless of the arrangement, the holograms 31, 32 can be implemented either as volume holograms or as relief holograms with a spectrally selective dielectric coating.

[0098] Phase functions of the holograms 31, 32 can either be defined by the interference of plane and / or spherical waves and / or correspond to free-form phase functions, which can be determined by the holographic exposure setups used to expose the holograms 31, 32.

Claims

August 12, 2025 Carl Zeiss Jena GmbH Z175585 ANE / Mak Claims 1. Imaging system for a driver's cab, wherein the imaging system comprises: a projection optic configured to output an image input as an image output; a holographic deflection unit configured to deflect the image output relative to an output direction of the image output; and an substantially transparent coupling unit configured to couple the image output deflected by the holographic deflection unit to an eyebox of the imaging system; wherein the imaging system is configured for a working distance between the projection optic and the coupling unit and / or between the coupling unit and the eyebox of 50 cm or less.

2. Imaging system for a driver's cab, the imaging system comprising: a projection optic configured to output an image input as an image output; a holographic deflection unit configured to deflect the image output relative to an output direction of the image output; and an substantially transparent output coupling unit configured to couple the image output deflected by the holographic deflection unit to an eyebox of the imaging system; wherein the output direction is at a non-zero angle to a plane spanned by a direction of the deflected image output and a direction of the coupled-out image output.

3. Imaging system according to claim 2, wherein the imaging system is configured for a working distance between the projection optics and the output coupling unit and / or between the output coupling unit and the eyebox of 50 cm or less.

4. Imaging system according to one of the preceding claims, wherein the holographic deflection unit projects a first hologram and a second hologram. Hologram comprises; wherein the first hologram is configured to redirect the image output to the second hologram; and wherein the second hologram is configured to redirect the image output to the coupling unit.

5. Imaging system according to claim 4, wherein the first and the second hologram comprise a reflection hologram, preferably a reflection relief hologram and / or a reflection volume hologram.

6. Imaging system according to one of claims 4 or 5, wherein the mean distance between the first and the second hologram is 20 mm or less, preferably 10 mm or less, or 1 mm or less.

7. Imaging system according to one of the preceding claims, wherein the deflection unit has an interaction surface configured to interact with the image output, wherein an area of ​​the interaction surface is 145% or less, preferably 120% or less, of a beam cross-section of the image output.

8. Imaging system according to one of the preceding claims, wherein the projection optics have an optical axis which is arranged substantially parallel to a direction of movement of the driver's cabin.

9. Imaging system according to one of the preceding claims, wherein a total deflection of the image output from the projection optics to the eyebox comprises a total angle of 150° to 210°, preferably 160° to 200°, or 170° to 190°.

10. Imaging system according to one of the preceding claims, wherein the projection optics are offset perpendicular to the direction of movement of the driver's cabin relative to the eyebox; and / or wherein the projection optics are positioned at the level of the eyebox or above it.

11. Imaging system according to one of the preceding claims, wherein the holographic deflection unit is configured to deflect the image output relative to the output direction at an angle of 20° or more, preferably more than 40° or more than 60°.

12. Imaging system according to one of the preceding claims, wherein the output unit is configured to generate a virtual image for a viewer within the eyebox.

13. Imaging system according to claim 12, wherein the virtual image has a field of view with a horizontal opening angle of 20° or more and / or a vertical opening angle of 15°. 0 or more.

14. Imaging system according to one of claims 12 or 13, wherein the virtual image is scaled to overlay an image visible through a window of the driver's cabin.

15. Imaging system according to one of the preceding claims, wherein the decoupling unit in a first state is at least partially positioned on a line of sight between a window of the driver's cabin and the eyebox.

16. Imaging system according to claim 15, wherein the decoupling unit is positioned in a second state outside the line of sight; and wherein the imaging system further comprises a means for switching between the first and the second state.

17. Imaging system according to one of the preceding claims, wherein the output coupling unit comprises a substantially transparent and spherically curved plane.

18. Imaging system according to one of the preceding claims, wherein the output coupling unit has an optical refractive power and / or a The hologram is designed to decouple the image output redirected by the holographic deflection unit to an eyebox.

19. Imaging system according to one of the preceding claims, wherein the eyebox has a volume of 390 cm³ 3 or more, includes.

20. Imaging system according to one of the preceding claims, further comprising: an imaging means configured to provide an image input to the projection optics.

21. Driver's cab with one or more imaging systems according to one of the preceding claims.

22. Vehicle with a driver's cab having one or more imaging systems according to any of the preceding claims.

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