Driving regime-dependent switchable hud display with a real or virtual hover image inside or outside a vehicle

Abstract

The invention relates to a method for operating a head-up display device (2) in a vehicle (1), which device is designed to produce a hover image in the field of view of a driver by reflection on a windshield (3) or a combiner screen, wherein - a projection unit (5) designed to output a light beam with desired display content is switchable between a normal and a relaxed position mode; - in the normal position mode, which is designed for a manually controlled driving regime with an associated normal position (NP) of the driver, a virtual hover image (V1) is produced outside the vehicle (1) at a predetermined first distance from the driver's eyes; and - in the relaxed position mode, which is designed for a (partially) autonomous driving regime with an associated relaxed position (RP) of the driver, a real or virtual hover image (V2) is produced inside or outside the vehicle (1) at a second, markedly shorter distance.

Description

[0001] Description

[0002] Trip-dependent switchable HUD display with a real or virtual floating image inside or outside a vehicle

[0003] The invention relates to methods for operating head-up display devices in motor vehicles or other land, air, or water vehicles, also known as head-up displays (HUDs). Such devices are designed to generate a virtual image projected into a driver's field of vision by reflection from an at least partially transparent reflective disk, which is configured as a windshield section or as a combiner disk provided specifically for this purpose in the driver's field of vision. The invention also relates to a correspondingly configured control unit, a projection unit configured to output a suitable light beam, a head-up display device containing the same, and a vehicle equipped therewith.

[0004] Head-up displays (HUDs) currently available for motor vehicles generally have a virtual image plane at a suitable distance in front of the vehicle, where driver information such as speed limits and current vehicle speed, warnings and navigation information, or even entertainment are displayed as a virtual image superimposed on the real image of the surroundings in front of the vehicle observed by the driver. The virtual image position and distance are usually selected to minimize distraction and strain for drivers while performing their driving tasks by focusing their eyes on the virtual image and without having to avert their gaze from the road.For this purpose, a field of vision display device comprises a projection unit, typically located in the instrument panel, which generates a light beam with the desired display content and projects it in a suitable shape and direction onto the windscreen of the vehicle or onto a combiner screen arranged in the driver's field of vision, from which it is reflected to his eyes.

[0005] The spatial position of the virtual image plane results from the optical interaction of the reflection screen (such as the windshield or combiner screen) and the components of the projection unit intended for beam generation, shaping, and steering, such as an image-generating display and beam-deflecting, imaging, and / or correcting optics in the form of one or more mirrors, etc. For future HUD technologies for road vehicles, one known approach is one in which the virtual image plane is not positioned vertically as usual, but almost parallel to the road. This can create a depth or 3D effect for the viewer. As described, for example, in DE 11 2019 003 420 T5, a virtual image can be constantly displayed while a vehicle is moving, which is perceived as being attached to the road surface.

[0006] Furthermore, DE 10 2019 206 956 A1, for example, proposes a display device designed as a head-up display for future vehicles, which additionally comprises a movable projection surface that is movable between a first, retracted position and a second, extended position, and rests with its surface on a windshield of the vehicle in the second, extended position. It is proposed that this projection surface be used only in an autonomous driving mode of the vehicle in its second, extended position to entertain the driver by displaying information from an entertainment system, such as films and / or images, directly on the projection surface, which can be non-transparent for this purpose.When the vehicle is in manual driving mode, this projection surface is in its first, retracted position to enable the HUD to function in its traditional way, displaying a visible image containing useful information about the vehicle's status, etc., on a virtual screen within the driver's field of vision. The virtual screen appears to float in the environment. This information is thus superimposed on the environment so that the driver can maintain an eye on the surroundings and quickly refocus on the road. When transitioning from autonomous to manual driving mode, the opaque projection surface must be moved out of the driver's field of vision, which can lead to additional distraction, especially when the driver urgently needs to take over.In addition, the display in autonomous driving mode is limited to this projection surface on the windshield, which must be retracted in its entirety into the interior of the instrument panel for manual driving mode.

[0007] It is an object of the present invention to provide an alternative and / or improved method with regard to installation space, display options and / or other aspects, and a correspondingly designed projection unit and field of view display device for a vehicle.

[0008] This object is achieved by a method according to claim 1 for operating a visual field display device in a vehicle, as well as by a corresponding control unit, projection unit, a visual field display device containing the same, and a vehicle equipped therewith according to the independent claims. Further embodiments are specified in the dependent claims. All further features and effects mentioned in the claims and in the following description for the method also apply to the control unit, the projection unit, the visual field display device, and the vehicle, and vice versa.

[0009] According to a first aspect, a method is provided for operating a field of view display device in a vehicle, which can be designed, in particular, as a head-up display (HUD). The vehicle can be a motor vehicle, but also any other land, air, or water vehicle. The spatial orientation terms used herein, such as "vertical," "horizontal," "higher / lower," "lowering," "in front of / behind," "below / above," etc., always refer to the usual vehicle-fixed Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and vertical directions of the vehicle.

[0010] The field of view display device is designed to generate a real or virtual image floating in the air (hereinafter referred to as a "floating image") in the driver's field of vision via reflection from a windshield or a specially provided combiner screen. For this purpose, the field of view display device has a projection unit designed to generate and output a light beam in the required shape and direction and with the desired display content toward the windshield, and which is switchable between a normal position mode and at least one relaxed position mode. For this purpose, a switching device in the form of an electrically controllable actuator, etc., at least partially integrated into the projection unit, can be provided in the vehicle.

[0011] In the normal position mode, which is designed for a driving regime manually controlled by the driver with an associated predetermined normal position of the driver, a virtual floating image is generated outside the vehicle at a predetermined first distance from the driver's eyes, which is designed for simultaneous observation of the road or an environment in front of the vehicle. In particular, this virtual floating image can be generated in the present method in a virtual image plane inclined to the horizontal or even aligned ("lying") with it in order to create a sense of depth or a contact-analog effect, i.e., a representation aligned with real surrounding objects. For this purpose, an image generator contained in the projection unit, for example a display, can be oriented in a conventional manner at a corresponding angle of inclination to the beam propagation direction.In the case of an inclined, horizontal, or curved virtual image plane, the said first distance of the floating image from the driver's eyes can be defined, for example, for a predetermined point of the virtual image plane or for its upper or lower image edge, etc. However, it can also be a vertical virtual image plane.

[0012] When reference is made here to the “driver’s eyes”, this can also be understood as a two- or three-dimensional spatial area (eyebox) within the vehicle, which is usually predetermined for a field of view display device and from which the floating image is visible to the driver in the intended quality.

[0013] In one or more different relaxed position modes, each designed for a uniquely associated autonomous or semi-autonomous driving regime with a corresponding predetermined relaxed position of the driver, a real or virtual floating image is generated inside or outside the vehicle at a respective predetermined second distance from the driver's eyes. This floating image can also be generated in a nearly vertical display plane or in a display plane inclined to the horizontal or even lying flat, as described above for the normal position mode. Each of these predetermined second distances is significantly smaller than the above first distance, so that the driver can focus their eyes significantly more closely on this floating image, for example, to switch effortlessly to other displays or objects in the vehicle's passenger compartment.

[0014] One idea behind this method is a combination of a focus change of a virtual or real floating image generated by a visual display device such as a head-up display in the field of vision of a vehicle driver, and a change in the driver's position caused by a transition from manual to autonomous and / or semi-autonomous driving or vice versa. Since the driver no longer needs to keep an eye on the road and the surroundings ahead of the vehicle during (semi-)autonomous driving, the proposed focus change of the floating image can enable a more comfortable simultaneous use of other on-board entertainment and pastime offerings, such as other displays and catering options in the vehicle interior, during (semi-)autonomous driving, for example, in spatial areas directly on or inside the vehicle.For example, after a transition to (semi-)autonomous driving, the driver can continue to use the HUD system without having to significantly refocus his eyes when looking at the central display or the center console.

[0015] By displaying a real or virtual floating image in the relaxed position mode, unlike the current state of the art, the windshield is not physically obscured, allowing the driver to see through it in an emergency and quickly take over. Furthermore, no additional projection screen is required; instead, the full flexibility of HUD technology, such as eye-tracking-based adjustment of the projection direction, is maintained. Furthermore, this allows for gradations between several different relaxed position modes, for example, to gradually bring the floating image closer to the vehicle interior and an area around the driver, depending on the level of automation.

[0016] By providing several different relaxed positions for the driver and corresponding relaxed position modes for the projection unit, different levels of autonomous driving, or the likelihood that the driver will be prompted to take over control of the vehicle or decide to do so on their own, can be accommodated. The different levels can range from a nearly upright sitting position with constant readiness to take over manually to a completely relaxed reclining position, intended for sleeping, among other things. Hereinafter, both the normal position mode and the one or more different relaxed position modes of the projection unit are collectively referred to as "modes."In particular, automatic switching of the projection unit between its normal position mode and its one or more relaxed position modes can be triggered by automatically detecting a change between the aforementioned driver positions, each clearly assigned to the various modes, and / or between the aforementioned driving regimes, each clearly assigned to the various modes. A sensor system, as described in the following paragraph, may be suitable for this purpose. Alternatively or additionally, manual switching by the driver is also possible, whereby, for example, this and other position or situation variants not covered by the automatic switching function can be taken into account and adapted by the driver to their individual needs by manually selecting the appropriate mode.

[0017] According to one embodiment, the transition from the driver's normal position to each of their relaxed positions is accompanied by a corresponding predetermined lowering of their torso or their head or eye height, which can be achieved, for example, by adjusting the angle of the backrest and / or lowering the entire driver's seat. The floating image is also displayed at correspondingly different heights when switching between the associated modes, which can, in particular, correspond to a predetermined typical viewing direction or viewing height of the driver in the respective mode or to their current viewing direction determined by eye tracking.For this purpose, at least one driver position sensor and / or eye-tracking unit can be provided in the vehicle, for example, which is designed and configured to detect and recognize the driver's current seating position and / or line of sight and to output a corresponding driver position sensor and / or eye-tracking signal to the projection unit. The sensor can, for example, comprise one or more suitable cameras, in particular infrared cameras to avoid any distraction of the driver, or seat occupancy sensors. Suitable sensors and / or eye-tracking units do not necessarily have to be part of the field of view display device, but can also be installed in the vehicle anyway for driver monitoring.

[0018] According to one embodiment, two or more different beam paths for the light beam are provided within the projection unit, between which beam paths a change (switch) is made for switching between the normal and the at least one relaxed position mode. Switching between these beam paths can be effected, for example, by at least one electrically switchable and / or mechanically movable polarization switching element that changes the polarization properties of the light beam. The polarization switching element can be designed, for example, as an X / 2 or X / 4 retarder or, alternatively, also on a liquid crystal (LC) basis. The individual beam paths are then designed to be polarization-dependent, so that the light beam can only propagate through a beam path intended for the respective mode.

[0019] In this case, a beam path provided for the normal position mode and at least one beam path provided for the at least one relaxed position mode can, for example, each comprise an optical imaging element (such as a concave mirror and / or a lens system) with a different predetermined strength of focusing of the light beam, whereby in the at least one relaxed position mode the said significantly smaller second distance of the floating image from the driver's eyes is effected compared to the normal position mode.For example, a conventional beam-shaping and image-magnifying concave mirror can be used in the normal beam path, while a significantly more curved concave mirror can be used in one of the relaxed beam paths. This creates a real (intermediate) floating image on the path of the light beam from the projection unit to the windshield / combiner screen or between the windshield / combiner screen and the eyebox. If a real intermediate floating image is created on the path of the light beam from the projection unit to the windshield / combiner screen, it is converted into a virtual image floating very close to the windshield / combiner screen by subsequent reflection. If a real floating image is created between the windshield / combiner screen and the eyebox, the driver only sees this real floating image at a correspondingly shorter distance in front of their eyes.Alternatively, the focusing strength can also be achieved by suitable manipulation of an optical imaging element with a variable focusing strength in a single beam path.

[0020] In particular, in the at least one relaxed position mode, a real or virtual floating image can be generated in a spatial area that extends inside the vehicle on or above an instrument panel and / or between the windscreen and a driver's seat or outside the vehicle above a hood.

[0021] According to a further aspect, a control unit is provided that is designed and configured to automatically execute the method presented herein. For this purpose, a corresponding computer program (software) can be loaded into a processor of the control unit, for example, and run during operation of the field-of-view display device.

[0022] According to a further aspect, a projection unit for a field-of-view display device for use in a vehicle is provided. The projection unit can, for example, be enclosed by a protective housing with a transparent cover plate. It comprises an image generator designed to generate a light beam with the desired display content, as well as at least partially the above-mentioned switching device, which is designed to switch the projection unit between its normal position mode and its at least one relaxed position mode. The projection unit is designed to output the light beam in a predetermined shape and direction such that it is subsequently reflected from a windshield or a combiner plate of the vehicle arranged in the driver's field of vision to the driver's eyes, thereby superimposing the display content into the driver's field of vision as an image floating in the air (floating image).

[0023] According to a further aspect, a field-of-view display device for a vehicle is provided, which comprises the above projection unit and a reflection disc, in particular a partially transparent one, arranged in the beam path of the light beam emitted by it. The reflection disc is arranged and configured in the driver's field of vision such that it reflects the light beam toward their eyes, thereby allowing the display content to be presented to them as a virtual or real floating image in their field of vision. Furthermore, the field-of-view display device comprises the above control unit.

[0024] According to a further aspect, the above vehicle, in particular a motor vehicle, is provided with mutually perpendicular longitudinal, transverse, and vertical directions of a vehicle-fixed Cartesian coordinate system. The vehicle comprises a windshield that at least partially defines a passenger compartment, as well as the above-mentioned field of view display device, whose projection unit is arranged in the passenger compartment, in particular inside an instrument panel arranged beneath the windshield, and whose reflection disc is designed as a section of the windshield or as a combiner disc arranged in the passenger compartment.

[0025] The above aspects of the invention and their embodiments and specific configurations are explained in more detail below with reference to the examples shown in the accompanying drawings. The drawings are to be understood as a purely schematic illustration of the basic optical functional principle, i.e., not to scale. They show:

[0026] Figure 1 is a longitudinal sectional view of a motor vehicle with a field of view display device according to an embodiment of the invention, the projection unit of which is operated in a normal position mode;

[0027] Figure 2 shows the vehicle of Figure 1 in the same longitudinal section, showing only the transition from a normal position of the driver according to Figure 1 to a relaxed position; and

[0028] Figure 3 shows the vehicle of Figures 1 and 2 in the same longitudinal section, with the projection unit operated in a relaxed position mode.

[0029] All of the various embodiments, variants, and specific design features of the method, the control unit, the projection unit, the field of view display device, and the vehicle according to the above aspects of the invention mentioned above in the description and in the subsequent claims can be implemented in the examples shown in Figures 1 to 3, in particular also alternatively or in addition to the features shown therein. Therefore, they will not all be repeated below. The same applies accordingly to the definitions and effects already given above with regard to individual features shown in Figures 1-3.

[0030] Fig. 1 to Fig. 3 each show, in the same highly simplified schematic longitudinal sectional view, a section of a vehicle 1 with a field of vision display device 2 according to an exemplary embodiment of the invention, which is designed to generate a virtual or real floating image V1 or V2 in the field of vision of a driver via reflection on a windshield 3. In this example, the vehicle 1 is a motor vehicle, which is indicated in Fig. 1 only by its windshield 3, an underlying instrument panel 4, and a steering wheel 5. The windshield 3 serves as the above-mentioned reflection plate of the field of vision display device 2, which is purely an example of a head-up display (HUD).

[0031] Inside the instrument panel, a projection unit 6 of the field of view display device 2 is housed, again only schematically indicated, which is designed to generate and output a light beam (not shown) with the desired display content toward the windshield 3. In this example, inside the projection unit 6, two different beam paths are provided for the light beam to be output, which contain concave mirrors (not shown) with different degrees of curvature, so that the projection unit 6 can be switched between a normal position mode shown in Fig. 1 and a relaxed position mode shown in Fig. 2 by switching between these two beam paths.

[0032] The normal position mode according to Fig. 1 is designed for a driving regime actively and manually controlled by the driver with an associated predetermined normal position NP of the driver in his driver's seat (not shown), which is illustrated in Fig. 1 by a corresponding position of his eyes. In this normal position mode, a virtual floating image V1 is generated outside the vehicle 1 at a predetermined first distance from the driver's eyes, which is well suited for simultaneously observing the road and an environment in front of the vehicle 1. In this example, the virtual floating image V1 is displayed in an image plane that is strongly inclined to the horizontal, the lower edge of which image is at a distance of approximately 3 m from the driver's eyes and the upper edge of which image is at a distance of approximately 6 m from the driver's eyes.

[0033] As indicated in Fig. 2 by a rotation arrow, when the driver changes to an autonomous driving regime in which he no longer participates in the vehicle control, for example by automatically adjusting his backrest (not shown) he moves into a more comfortable relaxed position RP, which in this example is a (semi-)reclining position and is recognizable in Fig. 2 by a correspondingly significantly lower position of his eyes.

[0034] Fig. 3 shows the associated relaxed position mode, which is designed for this autonomous driving regime and in which, in this example, a real floating image V2 is generated within the vehicle at a corresponding predetermined second, significantly smaller distance of approximately 0.8 m in front of the driver's eyes. The real floating image V2 floats in a spatial area slightly above the instrument panel 4 between the windshield 3 and the steering wheel 5, so that the driver views it while looking towards a lower section of the windshield. In particular, by using an eye-tracking device, the real floating image V2 can be tracked to the driver's current line of sight, so that the driver always has the real floating image V2 in view, even during movements of their body or head, which can often occur in a relaxed position.

[0035] The change of position or focus from the virtual floating image V1 to the real floating image V2 can be achieved by changing the polarization of an image generator (not shown) integrated in the projection unit 6 and a corresponding polarization dependence of the two

[0036] Visual ray paths / beam paths can be implemented. Alternatively, this can be done via independent visual ray paths. In this example, the change between the normal position mode of Fig. 1 and the relaxed position mode of Fig. 3 is performed automatically by a control unit 8, which is designed and configured to carry out the method presented herein. For example, the control unit 8 can detect position changes as in Fig. 2 based on signals from suitable sensors in the vehicle 1, such as camera systems, seat position or seat occupancy sensors, etc.

[0037] List of reference symbols

[0038] 1 vehicle

[0039] 2 Field of view display device

[0040] 3 Windscreen

[0041] 4 Instrument panel

[0042] 5 Steering wheel

[0043] 6 Projection unit

[0044] 8 Control unit

[0045] V1 virtual floating image

[0046] V2 real floating image

[0047] NP Normal position of the driver

[0048] RP Relaxed position of the driver

Claims

Claims 1. A method for operating a field of vision display device (2) in a vehicle (1), which is designed to generate an image floating in the air in the field of vision of a driver via reflection on a windshield (3) or a combiner screen, wherein a projection unit (6) designed to generate and output a light beam with the desired display content towards the windshield (3) is switchable between a normal position mode and at least one relaxed position mode; in the normal position mode, which is designed for a manually controlled driving regime with an associated predetermined normal position (NP) of the driver, a virtual floating image (V1) is generated outside the vehicle (1) at a predetermined first distance from the driver's eyes, which is designed for simultaneous observation of the road or an environment in front of the vehicle (1);and in the at least one relaxed position mode, which is designed for at least one autonomous or semi-autonomous driving regime with a respectively associated predetermined relaxed position (RP) of the driver, a real or virtual floating image (V2) is generated inside or outside the vehicle (1) at a respectively associated predetermined second, significantly smaller distance from the driver's eyes; 2. The method according to claim 1, wherein an automatic switching of the projection unit (6) between its normal position mode and its one or more different relaxed position modes is triggered by an automatic detection of a change between the said driver positions (NP, RP) which are each clearly assigned to the different modes and / or between the said driving regimes which are each clearly assigned to the different modes.

3. Method according to claim 1 or 2, wherein the transition from the normal position (NP) of the driver to each of his relaxed positions (RP) is accompanied by a respective associated predetermined lowering of his torso or his head or eye height; and when changing between the associated modes, the floating image (V1, V2) is displayed at correspondingly different heights, which in particular each correspond to a predetermined typical viewing direction or viewing height of the driver in the respective mode or his current viewing direction determined by eye tracking.

4. Method according to one of the preceding claims, wherein two or more different beam paths for the light beam are provided within the projection unit (6), between which beam paths switching is carried out for switching between the normal and the at least one relaxed position mode; wherein the switching between these beam paths is preferably effected by at least one electrically switchable and / or mechanically movable polarization switching element.

5. The method according to claim 4, wherein a beam path provided for the normal position mode and at least one beam path provided for the at least one relaxed position mode each comprise an optical imaging element with a mutually different predetermined strength of focusing of the light beam, whereby in the at least one relaxed position mode the said significantly smaller second distance of the floating image (V2) from the driver's eyes is effected compared to the normal position mode.

6. Method according to one of the preceding claims, wherein in the at least one relaxed position mode a real or virtual floating image (V2) is generated in a spatial region which extends inside the vehicle (1) on or above its instrument panel (4) and / or between the windscreen (3) and a driver's seat or outside the vehicle (1) above its bonnet.

7. Control unit (8) which is designed and configured to automatically execute the method according to one of the preceding claims.

8. Projection unit (6) for a field of view display device (2) for use in a vehicle (1), comprising: an image generator designed to generate a light beam with the desired display content; and a switching device designed to switch the projection unit (6) between its normal position mode and its at least one relaxed position mode; wherein the projection unit (6) is designed to output the light beam in such a predetermined form and Direction is designed so that it is then reflected from a windscreen (3) or a combiner disc arranged in the driver's field of vision to his eyes and the display content is thereby displayed in his field of vision as an image (V1, V2) floating in the air.

9. A field of vision display device (2) for a vehicle (1), comprising: a projection unit (6) according to claim 8; a control unit (8) according to claim 7, which is designed to control the switching device in order to carry out the method according to one of claims 1 to 6; and a reflection plate, in particular one which is at least partially transparent, arranged in the beam path of the light beam emitted by the projection unit (6), which is arranged and designed in the driver's field of vision in such a way that it reflects the light beam towards his eyes, whereby the display content can be presented to him as a virtual or real floating image (V1, V2) in his field of vision.

10. A vehicle (1), in particular a motor vehicle, with mutually perpendicular longitudinal, transverse and vertical directions of a vehicle-fixed Cartesian coordinate system, comprising: a windscreen (3) which at least partially delimits a passenger compartment; and a field of view display device (2) according to claim 9, whose projection unit (6) is arranged in the passenger compartment, in particular inside an instrument panel (4) arranged below the windscreen (3), and whose reflection disc is designed as a section of the windscreen (1) or as a combiner disc arranged in the passenger compartment.

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