Head-up display device which can be switched depending on driving state and which has real or virtual floating image inside or outside vehicle

Abstract

The invention relates to a method for operating a field-of-view display device (2) in a vehicle (1), which field-of-view display device is designed to generate an aerial-suspended image in the field of view of a driver by reflection on a windscreen (3) or a combination mirror, a projection unit (5) designed to output a light beam with desired display content can be switched between a normal position mode and a relaxed position mode; a normal position mode, which is designed for a manually controlled driving state in which the driver is in a corresponding predetermined normal position (NP), in which a virtual floating image (V1) is generated outside the vehicle (1) at a predetermined first distance from the driver's eyes, the predetermined first distance design is used for observing the road or the surrounding environment in front of the vehicle (1) at the same time; and-the relaxed position pattern is designed for a (semi) automatic driving state in which the driver is in a respective predetermined relaxed position (RP), in which a real or virtual floating image (V2) is generated inside or outside the vehicle (1) at a second significantly smaller distance.

Description

Technical Field

[0001] The present invention relates to a method for operating a visual field display device, also known as a head-up display (HUD), in a motor vehicle or other land, air, or water vehicle. Such a device is designed to generate a virtual image for display in the driver's field of view by reflection on an at least partially transparent reflector, which is designed as a windshield segment or as a specially designed combined mirror located in the driver's field of view. The invention also relates to a correspondingly configured control unit, a projection unit designed to output a suitable light beam, a visual field display device including the projection unit, and a vehicle equipped with the visual field display device. Background Art

[0002] Currently available head-up displays (HUDs) in motor vehicles typically feature a virtual image plane at an appropriate distance in front of the vehicle. Driver information, such as speed limits and current vehicle speed, warnings and navigation instructions, or entertainment content, is displayed on this image plane in the form of a virtual image, superimposed on the driver's view of the real environment in front of the vehicle. The virtual image position and distance are typically selected so that the driver minimizes distraction and visual fatigue caused by focusing on the virtual image while performing their driving tasks, without having to take their eyes off the road. To this end, the field of view display device includes a projection unit, typically mounted in the instrument panel, that generates a light beam with the desired display content and projects it in an appropriate shape and direction onto the vehicle's windshield or a combination mirror positioned in the driver's field of view, where it is reflected to the driver's eyes.

[0003] Here, the spatial position of the virtual image plane is determined by the optical interaction between the reflector (such as the windshield or combined mirror) and the components of the projection unit for beam generation, shaping and guidance (such as the image-generating display and the optical devices for beam deflection, imaging and / or correction in the form of one or more reflectors). For future head-up display technology for road vehicles, there is also a known solution in which the virtual image plane is not set vertically as usual, but is almost parallel to the road surface. This can give the observer a sense of depth or a 3D effect. For example, as described in DE 11 2019 003 420 T5, when the vehicle is driving, a virtual image can be continuously displayed, which is perceived as being attached to the road surface.

[0004] Furthermore, for example, DE 10 2019 206 956 A1 proposes a display device designed as a head-up display for future vehicles. The display device also includes a movable projection surface that is movable between a first retracted position and a second extended position. In the second extended position, the projection surface rests against the vehicle's windshield. It is proposed that the projection surface be positioned in the second extended position only when the vehicle is in autonomous driving mode, in order to entertain the driver by displaying information from an entertainment system (such as movies and / or images) directly on the projection surface. For this purpose, the projection surface can be opaque. In manual driving mode, the projection surface is in its first retracted position, allowing the head-up display to function in its conventional manner, displaying images visible to the driver, including useful information such as the vehicle status, on a virtual screen in the driver's field of view. The virtual screen appears to float above the surroundings. This information is displayed superimposed on the surroundings, allowing the driver to maintain their attention or quickly refocus on road traffic. When transitioning from automated to manual driving mode, the opaque projection surface must be removed from the driver's field of view, which can cause additional distraction if the driver urgently takes over. Furthermore, the display in automated driving mode is limited to the projection surface resting on the windshield, while in manual driving mode, the projection surface must be retracted to its full size within the instrument panel. Summary of the Invention

[0005] The object of the present invention is to provide an alternative and / or improved method with respect to installation space, display possibilities and / or other aspects, as well as a correspondingly designed projection unit and field display device for a vehicle.

[0006] This object is achieved by a method for operating a visual display device in a vehicle according to claim 1, and by a corresponding control unit, a projection unit, a visual display device including the projection unit, and a vehicle equipped with the visual display device according to the independent claims. Further embodiments are provided in the dependent claims. All other features and effects mentioned in the claims and the following description with respect to the method also apply to the control unit, the projection unit, the visual display device, and the vehicle, and vice versa.

[0007] According to a first aspect, a method for operating a field of view display device in a vehicle is provided, wherein the field of view display device can be configured as a head-up display (HUD). The vehicle can be a motor vehicle or any other land, air, or water vehicle. Spatial direction terms used herein, such as "vertical," "horizontal," "higher / lower," "lower," "front / rear," "below / above," etc., always refer to a fixed Cartesian coordinate system of the vehicle, having mutually perpendicular longitudinal, transverse, and height directions.

[0008] Here, the visual field display device is configured to generate a real or virtual image suspended in mid-air (hereinafter referred to as a "suspended image") in the driver's field of view by reflection on the windshield or a specially configured combination mirror. To this end, the visual field display device includes a projection unit configured to generate and output a light beam with desired display content in a desired shape and direction to the windshield, and is switchable between a normal position mode and at least one relaxed position mode. To this end, a switching device at least partially integrated into the projection unit can be provided in the vehicle, the switching device being in the form of an electrically controllable actuator or the like.

[0009] In the normal position mode (which is applicable to driving conditions in which the driver is manually controlling the vehicle in a relevant predetermined normal position), a virtual suspended image is generated outside the vehicle at a predetermined first distance from the driver's eyes, the first distance being designed for simultaneous observation of the road or the surrounding environment in front of the vehicle. In particular, in the present method, the virtual suspended image can be generated in a virtual image plane that is tilted or even parallel ("flat") relative to the horizontal plane to produce a depth effect or a contact simulation effect, that is, a display effect that is aligned with objects in the real environment. To this end, the image generator (e.g. a display) contained in the projection unit can be oriented at a corresponding tilt angle relative to the direction of propagation of the light beam in a manner known per se. In the case of an inclined, horizontal or curved virtual image plane, the above-mentioned first distance of the suspended image from the driver's eyes can be determined, for example, for a predetermined point of the virtual image plane or for the image edge of its upper and lower parts, etc. However, it can also be a vertical virtual image plane.

[0010] When referring to "driver's eyes" here, it can also be understood as a two-dimensional or three-dimensional spatial area (eye box) inside the vehicle, which is usually predetermined by the field of view display device, from which the driver can see the floating image with a predetermined quality.

[0011] In one or more different relaxed position modes (each designed for a unique, corresponding autonomous or semi-autonomous driving state with the driver in a corresponding predetermined relaxed position), a real or virtual floating image is generated inside or outside the vehicle at a predetermined second distance from the driver's eyes. As described above for the normal position mode, the floating image can also be generated on a display surface that is nearly vertical, tilted relative to the horizontal, or even flat. Each predetermined second distance is significantly smaller than the first distance, allowing the driver to focus their eyes significantly more closely on the floating image, for example, to easily switch to other displays or objects in the vehicle's passenger compartment.

[0012] One concept of this method is to combine the focus shift of a virtual or real floating image generated by a field of view display device (such as a head-up display) in the vehicle driver's field of view with the driver's position shift caused by the transition from manual driving to automated and / or semi-automated driving, or vice versa. Because the driver no longer needs to pay attention to the road and the surrounding environment in front of the vehicle during (semi-)automated driving, the proposed floating image focus shift can, for example, allow the driver to more comfortably use other entertainment and leisure facilities in the vehicle during (semi-)automated driving, such as other displays and dining facilities in the passenger compartment. For example, after the transition to (semi-)automated driving, the driver can continue to use the head-up display system without having to significantly adjust their eye focus when viewing the central display or center console.

[0013] Compared to existing technologies, by displaying a real or virtual floating image in the relaxed position mode, the windshield is not physically obstructed, allowing the driver to always see through it and quickly take over driving when necessary. Furthermore, no additional projection screen is required, while retaining the full flexibility of head-up display technology, such as eye-tracking-based projection direction tracking. Furthermore, this makes it possible to grade between multiple different relaxed position modes, for example, gradually bringing the floating image into the vehicle interior and the spatial area around the driver, depending on the level of automation.

[0014] By setting a number of different relaxed positions for the driver and the associated relaxed position modes for the projection unit, different levels of automated driving can be considered, or the possibility of the driver being asked to take over vehicle control or taking over at their own discretion. The different levels can range from an almost upright sitting position (ready to take over manually at any time) to a completely relaxed ("relaxed") lying position (including a position suitable for sleeping). In the following text, the normal position mode of the projection unit and one or more different relaxed position modes will be collectively referred to as a "mode."

[0015] In particular, the automatic switching of the projection unit between its normal position mode and one or more relaxed position modes can be triggered by automatically detecting changes between the driver's positions uniquely associated with the different modes and / or changes between the driving states uniquely associated with the different modes. For example, the sensor system mentioned in the next paragraph may be suitable for this purpose. Alternatively or additionally, the driver can also perform manual switching, for example, so that these and other position or situation variations not covered by the automatic switching can be taken into account and adjusted to their personal needs by manually selecting the appropriate mode.

[0016] According to one embodiment, the driver's transition from a normal position to one of their relaxed positions causes a corresponding predetermined lowering of their torso, head, or eye height, respectively. This can be achieved, for example, by adjusting the tilt angle of the backrest and / or lowering the entire driver's seat. When switching between different modes, the floating image is displayed at correspondingly different heights, which in particular correspond to the driver's typical predetermined gaze direction or gaze height in the respective mode, or to the driver's current gaze direction as determined by eye tracking. To this end, at least one driver position sensor and / or eye tracking unit can be provided in the vehicle, which is constructed and configured to detect and identify the driver's current sitting position and / or gaze direction and output corresponding driver position sensor signals and / or eye tracking signals to the projection unit. This sensor can, for example, include one or more suitable cameras, particularly infrared cameras (to avoid any interference with the driver), or a seat occupancy sensor. 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 for driver monitoring.

[0017] According to one embodiment, two or more different optical paths for the light beam are provided inside the projection unit, and switching between the normal position mode and the at least one relaxed position mode is achieved by transforming (switching) between these optical paths. Switching between these optical paths can be achieved, for example, by at least one electrically switchable and / or mechanically movable polarization switching element, which changes the polarization characteristics of the light beam. The polarization switching element can, for example, be constructed as a λ / 2 or λ / 4 retarder, or alternatively as a liquid crystal (LC)-based one. The individual optical paths are correspondingly constructed according to the polarization, so that the light beam can only propagate through the optical path determined for the corresponding mode.

[0018] Here, the optical path for the normal position mode and at least one optical path for at least one relaxed position mode can, for example, each include an optical imaging element (such as a concave mirror and / or lens system) having different predetermined beam focusing intensities, so that in the at least one relaxed position mode, the second distance of the suspended image from the driver's eyes is significantly smaller than in the normal position mode. For example, a conventional concave mirror for beam shaping and image magnification can be used in the normal optical path, while a concave mirror with a significantly greater curvature can be used in one of the relaxed optical paths, resulting in the generation of a real (intermediate) suspended image on the path of the light beam from the projection unit to the windshield / combination mirror or between the windshield / combination mirror and the eye box. If a real intermediate suspended image is generated on the path of the light beam from the projection unit to the windshield / combination mirror, the intermediate suspended image is converted into a virtual image that is suspended very closely on the other side of the windshield / combination mirror through subsequent reflection on the windshield / combination mirror. If a true floating image is generated between the windshield / combination mirror and the eye box, the driver will only see this true floating image at a correspondingly shorter distance in front of the driver's eyes. Alternatively, the focus intensity can also be achieved by appropriately controlling an optical imaging element with variable focus intensity in a single optical path.

[0019] In particular, in the at least one relaxed position mode, a real or virtual floating image can be generated in a spatial region which extends inside the vehicle at or above the dashboard and / or between the windshield and the driver's seat or outside the vehicle above the hood.

[0020] According to another aspect, a control unit is provided, which is constructed and configured to automatically perform the method proposed herein. For this purpose, for example, a corresponding computer program (software) can be loaded into a processor of the control unit and executed when the visual field display device is running.

[0021] According to another aspect, a projection unit for a field of view display device for use in a vehicle is provided. For example, the projection unit may be enclosed by a protective housing with a transparent cover. The projection unit includes an image generator configured to generate a light beam with desired display content and at least a portion of the aforementioned switching device configured to switch between a normal position mode and at least one relaxed position mode of the projection unit. The projection unit is configured to output a light beam in a predetermined shape and direction, such that the light beam is subsequently reflected by the vehicle's windshield or a combination mirror disposed in the driver's field of view toward the driver's eyes, thereby causing the display content to appear in the driver's field of view as an image suspended in mid-air (a suspended image).

[0022] According to another aspect, a field of view display device for a vehicle is provided. The field of view display device includes the aforementioned projection unit and a reflector (particularly, an at least partially transparent reflector) disposed in the path of light output by the projection unit. The reflector is arranged and configured in the driver's field of view so as to reflect a light beam toward the driver's eyes, thereby enabling display content to be displayed as a virtual or real floating image in the driver's field of view. The field of view display device also includes the aforementioned control unit.

[0023] According to another aspect, a vehicle, in particular a motor vehicle, is provided, having a vehicle-stationary Cartesian coordinate system with mutually perpendicular longitudinal, transverse, and height directions. The vehicle comprises a windshield, which at least partially delimits a passenger compartment, and a field of view display device, wherein the projection unit of the field of view display device is located in the passenger compartment, in particular within an instrument panel arranged below the windshield, and the reflector is designed as a section of the windshield or as a combination mirror arranged in the passenger compartment. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above aspects of the present invention and their implementation and specific configurations will be explained in more detail below with reference to the examples shown in the accompanying drawings. These drawings should be understood as purely schematic illustrations of the basic optical functional principles and are not drawn to scale. In the drawings:

[0025] Figure 1 is a longitudinal sectional view of a motor vehicle having a field of view display device according to an embodiment of the present invention, wherein a projection unit of the field of view display device operates in a normal position mode;

[0026] Figure 2 yes Figure 1 The same longitudinal section of the vehicle in FIG, showing only the driver's Figure 1 transition from the normal position to the relaxed position; and

[0027] Figure 3 yes Figure 1 and Figure 2 Same longitudinal section of a vehicle with the projection unit operating in the relaxed position mode. DETAILED DESCRIPTION

[0028] exist Figures 1 to 3 In the example shown, all the different embodiments, variants and specific configuration features of the method, control unit, projection unit, field display device and vehicle according to the above aspects of the invention mentioned in the above description and the following claims can be implemented, in particular as an alternative to or in addition to the features shown in the drawings. Therefore, all of these will not be repeated below. Similarly, the above-mentioned Figures 1 to 3 The term definitions and effects of the individual features shown in also apply accordingly.

[0029] Figures 1 to 3 A portion of a vehicle 1 is shown in each case in a highly simplified schematic longitudinal sectional view, which has a field of view display device 2 according to an embodiment of the present invention, which is configured to generate a virtual or real floating image V1 or V2 in the driver's field of view by reflection on a windshield 3. In this example, the vehicle 1 is a motor vehicle. Figure 1 The motor vehicle is shown schematically only by its windshield 3, an instrument panel 4 located below the windshield, and a steering wheel 5. The windshield 3 serves as the aforementioned reflector for the visual field display device 2, which is exemplarily a head-up display (HUD).

[0030] A projection unit 6 (also shown schematically) of the visual field display device 2 is installed inside the instrument panel. The projection unit is configured to generate a light beam (not shown) with desired display content and output it to the windshield 3. In this example, two different light paths are set inside the projection unit 6 for the light beam to be output. These light paths contain concave mirrors (not shown) with significantly different curvatures, so that the projection unit 6 can switch between the two light paths. Figure 1 Normal position mode shown and Figure 2 Switch between the relaxation position modes shown.

[0031] according to Figure 1 The normal position mode is designed for a driving state in which the driver is actively and manually controlled, wherein the driver is in a corresponding predetermined normal position NP in his driver's seat (not shown), Figure 1 This normal position is illustrated by the corresponding position of the driver's 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 the environment in front of the vehicle 1. In this example, the virtual floating image V1 is displayed in an image plane that is significantly tilted relative to the horizontal plane, with the lower image edge of the image plane approximately 3 meters from the driver's eyes and the upper image edge of the image plane approximately 6 meters from the driver's eyes.

[0032] like Figure 2 As shown by the rotating arrow in FIG, when changing to the automatic driving state (when the driver is no longer involved in the vehicle control), the driver is transferred to a more comfortable relaxation position RP, for example by automatic adjustment of his backrest (not shown), which is a (semi-) reclining position in this example and Figure 2 The center is visible through a correspondingly significantly lower position of the driver's eyes.

[0033] Figure 3A corresponding relaxed position mode is shown, which is designed for the described automated driving state and, in this example, generates a realistic floating image V2 within the vehicle interior at a corresponding predetermined second distance (which is significantly smaller) of approximately 0.8 meters in front of the driver's eyes. The realistic floating image V2 is suspended approximately above the instrument panel 4 in the spatial region between the windshield 3 and the steering wheel 5, so that the driver can observe it when looking toward the lower portion of the windshield. In particular, by using an eye-tracking device, the realistic floating image V2 can track the driver's respective current gaze direction, so that the driver can always see the realistic floating image V2 even when the driver's body or head moves (which can often occur, especially in the relaxed position).

[0034] Here, the position or focus change from the virtual levitation image V1 to the real levitation image V2 can be achieved by changing the polarization of the image generator (not shown) integrated in the projection unit 6 and the corresponding polarization correlation of the two sight paths / light paths. Alternatively, this can be achieved by independent sight paths. In this example, Figure 1 Normal position mode and Figure 3 The change between the relaxed position modes is automatically performed by a control unit 8, which is constructed and configured to perform the method proposed herein. For example, the control unit 8 can detect the following based on signals from suitable sensors in the vehicle 1 (such as a camera system, a seat position sensor or a seat occupancy sensor, etc.). Figure 2 The position changes shown in .

[0035] List of reference numerals:

[0036] 1 vehicle

[0037] 2-field display device

[0038] 3 Windshield

[0039] 4 Instrument panel

[0040] 5. Steering wheel

[0041] 6 projection units

[0042] 8 Control Unit

[0043] V1 Virtual Levitation Image

[0044] V2 Real Levitation Image

[0045] NP Driver's Normal Position

[0046] RP Driver's relaxed position.

Claims

1. A method for operating a field of view display device (2) in a vehicle (1), wherein the field of view display device is configured to generate an image suspended in the driver's field of view by reflection on a windshield (3) or a combination mirror, wherein: a projection unit (6) configured to generate a light beam with desired display content and output it to the windshield (3) and capable of switching between a normal position mode and at least one relaxed position mode; - the normal position mode is designed for a manually controlled driving state in which the driver is in a corresponding predetermined normal position (NP), in which a virtual floating image (V1) is generated outside the vehicle (1) at a predetermined first distance from the driver's eyes, the predetermined first distance being designed for simultaneously observing the road or the surrounding environment in front of the vehicle (1); and - The at least one relaxation position mode is designed for at least one automatic or semi-automatic driving state when the driver is in a respectively corresponding predetermined relaxation position (RP), and in the at least one relaxation position mode, a real or virtual floating image (V2) is generated inside or outside the vehicle (1) at a respectively corresponding significantly smaller predetermined second distance from the driver's eyes.

2. The method according to claim 1, wherein The automatic switching of the projection unit (6) between its normal position mode and one or more different relaxed position modes thereof is triggered by automatically identifying a change between the driver positions (NP, RP) respectively corresponding to different modes and / or a change between the driving states respectively corresponding to different modes.

3. The method according to claim 1 or 2, wherein: - the transition of the driver from the normal position (NP) to any of his / her relaxed positions (RP) causes a corresponding predetermined decrease in the driver's torso or head height or eye height; and -When switching between relevant modes, the floating images (V1, V2) are displayed at corresponding different heights, which in particular correspond to the driver's typical predetermined viewing direction or viewing height in the corresponding mode, or to the driver's current viewing direction determined by eye tracking.

4. A method according to any one of the preceding claims, wherein - two or more different optical paths for the light beam are provided inside the projection unit (6), and switching between the normal position mode and the at least one relaxed position mode is achieved by switching between these optical paths; The switching between the 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 The optical path set for the normal position mode and at least one optical path set for the at least one relaxed position mode respectively include an optical imaging element, and the optical imaging elements have predetermined light beam focusing intensities that are different from each other, so that in the at least one relaxed position mode, the second distance of the suspended image (V2) from the driver's eyes is significantly smaller than that in the normal position mode.

6. A method according to any one of the preceding claims, wherein In the at least one relaxation position mode, a real or virtual floating image (V2) is generated in a spatial region which extends inside the vehicle (1) at or above the vehicle's dashboard (4) and / or between the windshield (3) and the driver's seat or outside the vehicle (1) above the vehicle's hood.

7. A control unit (8) designed and configured to automatically carry out the method according to any one of the preceding claims.

8. A projection unit (6) for a field of view display device (2) for use in a vehicle (1), the projection unit comprising: an image generator configured to generate a light beam with a desired display content; as well as a switching device designed to switch the projection unit (6) between its normal position mode and at least one relaxed position mode; - wherein the projection unit (6) is configured to output a light beam in a predetermined shape and direction, so that the light beam is then reflected by the windshield (3) or a combination mirror arranged in the driver's field of view to the driver's eyes, thereby making the display content appear to the driver as an image (V1, V2) suspended in the air in the driver's field of view.

9. A field of view display device (2) for a vehicle (1), the field of view display device comprising: - The 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 any one of claims 1 to 6; as well as - a reflector, in particular an at least partially transparent reflector, arranged in the optical path of the light beam output by the projection unit (6), the reflector being arranged and constructed in the driver's field of view so that it reflects the light beam to the driver's eyes, thereby making the display content visible to the driver as a virtual or real floating image (V1, V2) in the driver's field of view.

10. A vehicle (1), in particular a motor vehicle, having a longitudinal direction, a transverse direction and a height direction of a vehicle-fixed Cartesian coordinate system perpendicular to one another, the vehicle comprising: - a windshield (3) which at least partially delimits the passenger compartment; as well as - A field of view display device (2) according to claim 9, wherein the projection unit (6) of the field of view display device is located in the passenger compartment, in particular inside the instrument panel (4) arranged below the windshield (3), and the reflector of the field of view display device is constructed as a section of the windshield (1) or as a combination mirror arranged in the passenger compartment.

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