Head-up display for a means of transport

Abstract

The present invention relates to a head-up display (1) for a means of transport. The invention also relates to a means of transport having such a head-up display (1). The head-up display (1) has an imaging unit (10) and projection optics (17). The imaging unit (10) has two display devices (11R, 11L) for generating a first image (BR) for the right eye of a viewer (3) and a second image (BL) for the left eye of the viewer (3). The two display devices (11R, 11L) can each be displaced in three spatial directions relative to an enlargement path of the head-up display (1). The projection optics (17) are designed to reproduce the first image (BR) in a first image plane and to reproduce the second image (BL) in a second image plane. The first image plane and the second image plane are located as free focal planes in a shaft (16) directly in the air.

Description

[0001]202207244 1 Description Head-up display for a means of transport The present invention relates to a head-up display for a means of transport. The invention also relates to a means of transport with such a head-up display. A head-up display, also referred to as HUD, is a display system in which the viewer can maintain his or her line of sight because the content to be displayed is superimposed into his or her field of vision. While such systems were originally used primarily in the aviation sector due to their complexity and cost, they are now also being installed in large series in the automotive sector. Head-up displays generally consist of an imaging unit or PGU (Picture Generating Unit), an optical unit, and a mirror unit. The imaging unit generates the image and uses at least one display element to do so. The optical unit directs the image to the mirror unit.The mirror unit is a partially reflective, translucent pane. The viewer therefore sees the content displayed by the imaging unit as a virtual image and, at the same time, the real world behind the pane. In the automotive sector, the windshield often serves as the mirror unit, and its curved shape must be taken into account in the display. Due to the interaction of the optical unit and the mirror unit, the virtual image is an enlarged representation of the image generated by the imaging unit. The viewer can only view the virtual image from the position of the so-called eyebox. The eyebox or viewer window is an area whose height and width correspond to a theoretical viewing window. As long as one eye of the viewer is within the eyebox, all 202207244 2 elements of the virtual image are visible to the eye.If, however, the eye is located outside the eyebox, the virtual image is only partially visible to the viewer or not at all. Currently available head-up displays use a single large eyebox within which the viewer's head can move, allowing the viewer to see the same flat, two-dimensional image with both eyes. A pseudo-3D effect can sometimes be achieved using autostereoscopic approaches. Against this background, DE 3712170 A1 describes a stereoscopic display system. The display system has at least two display elements, an imaging optics system with a number of imaging elements corresponding to the number of display elements for generating an equal number of real intermediate images, and at least one magnifying glass for generating a real image of the aperture stops of the imaging elements in the viewer's eye area.DE 102013218085 A1 describes a head-up display for use in a motor vehicle with an image generation device that generates a real image, wherein the light rays of the real image reach a combiner, thus forming a beam path, and from there are reflected toward an observer, so that the observer can perceive a virtual image behind the combiner outside the motor vehicle. The image generation device is designed as a 3D display. Furthermore, a device for detecting the observer's viewing direction and a device for pre-distorting the real image are provided. It is an object of the present invention to provide a head-up display capable of generating 3D content. This object is achieved by a head-up display having the features of claim 1 and by a means of transportation according to claim 9. Preferred embodiments of the invention are the subject of the dependent claims.202207244 3 According to a first aspect of the invention, a head-up display comprises an imaging unit and projection optics. The imaging unit has two display devices for generating a first image for a viewer's right eye and a second image for a viewer's left eye. The two display devices are each displaceable in three spatial directions relative to a magnification path of the head-up display. The projection optics are configured to project the first image into a first image plane and to project the second image into a second image plane. The first image plane and the second image plane lie as free focal planes in a shaft directly in the air. The shaft ensures that no stray light enters the beam path. The shaft is sometimes also referred to as a light tunnel.The images in the free focal planes are sometimes referred to as aerial photographs or - in reference to the terminology used in microscopes - as a real intermediate image. In the solution according to the invention, the images are generated separately for the viewer's left and right eye using two display devices, e.g., two microdisplays. The projection optics project the images from the display devices into a shaft directly into free focal planes in the air, where they are visible as objects in space. The display devices can be moved in all spatial directions relative to the magnification path of the head-up display. This makes it possible to project the aerial photographs into the air to suit the visibility based on the eye position in the shaft. The displacement of the images in the shaft itself makes it possible to display information as a real 3D object in the viewer's field of vision.According to one aspect of the invention, the first image and the second image are tiltable. For this purpose, for example, the display devices can be tiltable. By tilting the images, a varifocal projection can be realized. 202207244 4 According to one aspect of the invention, the head-up display has a calculation unit that is configured to compensate for distortions individually for the first image and the second image. In particular, the calculation unit can be configured to compensate for distortions caused by a geometry of a projection surface or by the projection optics or other optical components. Since the images are generated separately for both eyes, the image quality can be improved separately for the left and right eye by compensating for typical distortions. For example,Variations in the geometry of the windshield or deviations in the projection optics of the head-up display caused by production can be compensated for. According to one aspect of the invention, the calculation unit is configured to access calibration values ​​stored in a memory for the compensation. The use of calibration values ​​makes it possible to determine the appropriate compensation for distortions individually for each head-up display after it has been installed in a means of transport. During calibration, the deviation between the actual image representation and the data status of the head-up display design is determined. According to one aspect of the invention, the display devices are moved based at least on data from camera-based monitoring of the viewer. Cameras for driver monitoring are used, for example, in motor vehicles to track the eyebox according to the viewer's position.The head position and eye positions of the viewer can easily be determined from the data from such cameras. These positions can be used to move the display devices accordingly. 202207244 5 According to one aspect of the invention, the head-up display is configured to display content as contact-analog augmentations in a road plane or as objects oriented perpendicular to the road plane. The head-up display according to the invention allows content to be displayed both according to a Scheimpflug projection, in which the content is located in the road, for example, as a contact-analog augmentation, and as objects oriented perpendicular to the road. In both cases, the content is available as true 3D information. A head-up display according to the invention is preferably used in a means of transport.The means of transport can be a motor vehicle, for example, but alternatively also an aircraft, a rail vehicle or a watercraft. Further features of the present invention will become apparent from the following description and the appended claims in conjunction with the figures. Overview of the figures Fig. 1 shows a schematic representation of a head-up display according to the prior art for a motor vehicle; Fig. 2 shows a schematic representation of a head-up display according to the invention; Fig. 3 shows a schematic representation of a displacement of display devices relative to a projection optics and to a magnification path of the head-up display; Fig. 4 shows a schematic representation of a displacement of an aerial image in a shaft of the head-up display; 202207244 6 Fig. 4 shows a schematic representation of a displacement of the aerial image relative to a light path of the head-up display; and Fig. 6 shows a schematic representation of a means of transport that uses a display system according to the invention.Description of the figures For a better understanding of the principles of the present invention, embodiments of the invention are explained in more detail below with reference to the figures. The same reference numerals are used in the figures for the same or similarly acting elements and are not necessarily described again for each figure. It is understood that the invention is not limited to the embodiments shown and that the described features can also be combined or modified without departing from the scope of the invention as defined in the appended claims. Fig. 1 shows a schematic diagram of a head-up display 1 according to the prior art for a motor vehicle. The head-up display 1 has an imaging unit 10 and an optical unit 12.Light SB emanates from a display element 11, is reflected by a folding mirror 21 onto a curved mirror 22, which reflects it towards a mirror unit 2. The mirror unit 2 is depicted here as the windshield 20 of the motor vehicle. From there, the light SB' travels towards the eye of an observer 3. The observer 3 sees a virtual image VB, which is located outside the motor vehicle above the hood or even in front of the motor vehicle. Due to the interaction of the optical unit 12 and the mirror unit 2, the virtual image VB is an enlarged representation of the image displayed by the display element 11. Here, a speed limit, the current vehicle speed, and navigation instructions are symbolically depicted. As long as the eye of the observer 3 is within an eyebox 4 indicated by a rectangle, all elements of the virtual image VB are visible to the observer 3.If the eye of the viewer 3 is located outside the eyebox 4, the virtual image VB is only partially visible or not visible at all to the viewer 3. The larger the eyebox 4, the less restricted the viewer is in choosing their seating position. The curvature of the curved mirror 22 is adapted to the curvature of the windshield 20 and ensures that the image distortion is stable across the entire eyebox 4. The curved mirror 22 is rotatably mounted by means of a bearing 23. The resulting rotation of the curved mirror 22 enables the eyebox 4 to be moved and thus the position of the eyebox 4 to be adjusted to the position of the viewer 3. The folding mirror 21 ensures that the path traveled by the light SB between the display element 11 and the curved mirror 22 is long, while at the same time the optical unit 12 remains compact.The imaging unit 10 and the optical unit 12 are separated from the environment by a housing 13 with a transparent cover plate 24. The optical elements of the optical unit 12 are thus protected, for example, against dust present in the interior of the vehicle. A cover arrangement 26 arranged on the cover plate 24 serves to reliably absorb the light reflected across the boundary surface of the cover plate 24, so that the viewer is not dazzled. In addition to sunlight SL, the light from another interfering light source 5 can also reach the display element 11. A polarization filter 25 arranged on the cover plate 24 can be used to reduce incident sunlight SL or interfering light. Fig. 2 schematically shows a head-up display 1 according to the invention. The head-up display 1 is largely identical to the head-up display 1 shown in Fig. 1.However, at the output of the imaging unit 10 202207244 8 there is now a shaft 16 in which the image is suspended in the air. In addition, the imaging unit 10 has two display devices 11R, 11L, e.g., two microdisplays. The two display devices 11R, 11L can each be moved in three spatial directions. The movement of the display devices 11R, 11L can be based, for example, on data from a monitoring system of the viewer 3, which evaluates images from an interior camera 18. Furthermore, the display devices 11R, 11L can also be tilted. The head-up display 1 has a calculation unit 14 that is configured to compensate for distortions individually for the two images of the display devices 11R, 11L. In particular, the calculation unit 14 can be configured to compensate for distortions caused by a geometry of the windshield 20 or by the projection optics 17 or other optical components 21, 22.Since the images are generated separately for each eye of the viewer 3, the image quality can be improved separately for the left and right eyes by compensating for typical distortions. For example, the calculation unit 14 can be configured to access calibration values ​​stored in a memory 15 for compensation. This allows the appropriate compensation for distortions to be determined individually for each head-up display 1 after installation in a means of transport. Fig. 3 schematically shows the displacement of the two display devices 11R, 11L relative to the projection optics and the magnification path of the head-up display. As can be seen, the two display devices 11R, 11L are displaceable in three spatial directions x, y, z. This makes it possible to project the images BR, BL of the display devices 11R, 11L into the air using the projection optics to match the visibility corresponding to the eye position in the shaft 16.This imaging is also referred to as generating an aerial image or intermediate image. 202207244 9 Fig. 4 schematically shows the displacement of an aerial image L in the shaft 16 of the head-up display. The projection optics are indicated here by an output projection lens 19. Fig. 5 schematically shows the displacement of the aerial image L relative to a light path of the head-up display. The displacement of the images in the shaft 16 itself makes it possible to display information as a real 3D object in the viewer's field of vision. The aerial image L is tracked in the shaft 16 to match the driver's head movement. Fig. 6 schematically shows a means of transport 30 that uses a head-up display 1 according to the invention. In this example, the means of transport 30 is a motor vehicle. The motor vehicle has a head-up display 1 according to the invention that uses a windshield 20 of the motor vehicle as a projection surface.A sensor system 31 can capture data on the vehicle's surroundings. The sensor system 31 can, in particular, comprise sensors for environmental detection, e.g., ultrasonic sensors, laser scanners, radar sensors, lidar sensors, or cameras. The information captured by the sensor system 31 can be used to generate content to be displayed on the head-up display 1. Further components of the motor vehicle in this example are a navigation system 32, which can provide position information, and a data transmission unit 33. Using the data transmission unit 33, a connection to a backend can be established, for example, to obtain updated software for components of the motor vehicle. A memory 34 is provided for storing data. Data is exchanged between the various components of the motor vehicle via a network 35.202207244 10 List of reference symbols 1 Head-up display 2 Mirror unit 3 Viewer 4 Eyebox 5 Stray light source 10' Imaging unit 11, Display element 11R, 11L 12 Optical unit 13 Housing 14 Calculation unit 15 Memory 16 Shaft 17 Projection optics 18 Camera 19 Output projection lens 20 Windshield 21 Folding mirror 22 Curved mirror 23 Bearing 24 Cover plate 25 Polarization filter 26 Cover arrangement 30 Means of transport 31 Sensor system 32 Navigation system 33 Data transmission unit 202207244 11 34 Memory 35 Network BR, BL Image L Aerial image SB, SB' Beam SL Sunlight VB Virtual image.

Claims

202207244 12 patent claims 1. Head-up display (1) for a means of transport (30), comprising: - an imaging unit (10) with two display devices (11R, 11L) for generating a first image (BR) for a right eye of a viewer (3) and a second image (BL) for a left eye of the viewer (3); and - projection optics (17) for projecting the first image (BR) into a first image plane and for projecting the second image (BL) into a second image plane; wherein the first image plane and the second image plane lie directly in the air as free focal planes in a shaft (16), and the two display devices (11R, 11L) are each displaceable in three spatial directions relative to a magnification path of the head-up display (1).

2. Head-up display (1) according to claim 1, wherein the first image (BR) and the second image (BL) are tiltable. 3.Head-up display (1) according to claim 2, wherein the display devices (11R, 11L) are tiltable to tilt the first image (BR) and the second image (BL).

4. Head-up display (1) according to one of the preceding claims, wherein the head-up display (1) has a calculation unit (14) configured to compensate for distortions individually for the first image (BR) and the second image (BL).

5. Head-up display (1) according to claim 4, wherein the calculation unit (14) is configured to compensate for distortions caused by a geometry of a projection surface (20) or by the optical unit (12). 202207244 13 6. Head-up display (1) according to claim 4 or 5, wherein the calculation unit (14) is configured to access calibration values stored in a memory (15) for the compensation.

7. Head-up display (1) according to one of the preceding claims, wherein the displacement of the display devices (11R, 11L) occurs based on at least data from camera-based monitoring of the viewer (3).

8. Head-up display (1) according to one of the preceding claims, wherein the head-up display (1) is configured to present content as contact-analog augmentation or as 3D information.

9. Means of transport (30) with a head-up display (1) according to one of the preceding claims.

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