WO2017084894A1

WO2017084894A1 - Cover element for covering a projection opening of a head-up display, head-up display, and method for guiding light through a cover element

Info

Publication number: WO2017084894A1
Application number: PCT/EP2016/076667
Authority: WO
Inventors: Reinhold Fiess; Tobias Werner
Original assignee: Robert Bosch Gmbh
Priority date: 2015-11-19
Filing date: 2016-11-04
Publication date: 2017-05-26
Also published as: EP3377933A1; DE102015222842A1; FR3044113A1; CN108292047A

Abstract

The invention relates to a cover element (506) for covering a projection opening (508) of a head-up display (500) for a vehicle (502), wherein the projection opening (508) is arranged in a beam path between an image generating unit (504) of the head-up display (500) and a deflecting element (510) of the vehicle (502). The cover element (506) comprises a polarisation changing element (516), which is designed in order to change a polarisation of a light beam (512) guided in the beam path between a first polarisation type and a second polarisation type, and a polarisation filter (514) which is transparent for a light beam (512) polarised in a predetermined polarisation direction in the second polarisation type, wherein said polarisation filter is or can be arranged between the polarisation changing element (516) and the windscreen (510).

Description

Description title

Cover element for covering a projection opening of a head-up display, head-up display and method for passing light through a cover

State of the art

The invention is based on a device or a method

Type of independent claims.

Modern vehicles may include head-up displays for projecting specific information into a field of view of a driver.

Disclosure of the invention

Against this background, the approach presented here is used

Covering for covering a projection opening of a head-up display for a vehicle, a head-up display for a vehicle and a method for guiding light through such a cover according to the main claims presented. The measures listed in the dependent claims advantageous refinements and improvements of the independent claim device are possible.

A cover element for covering a projection opening of a head-up display for a vehicle is presented, the projection opening being arranged in the mounted state of the head-up display in a beam path between an image generation unit of the head-up display and a deflecting element, the cover element having the following features: a polarization changing element configured to polarize a light beam guided in the beam path between a first polarization

Change polarization and a second polarization; and one for one in the second polarization mode in a predetermined one

Polarization direction polarized light beam permeable polarization filter, wherein the polarizing filter in the mounted state of the cover on a side facing away from the image forming unit

Polarization change element is arranged.

Under a cover can be understood a cover plate or other at least partially translucent element. The cover member may be formed to separate an interior of the head-up display from an exterior of the head-up display.

For example, the cover may be integrated into a dashboard of the vehicle and depending on the embodiment movable or rigidly connected thereto. For example, the cover member may have a flat or curved surface. Accordingly, the projection opening can be formed in the dashboard to fully accommodate the cover. Under a head-up display, a display device for

Showing information in the form of virtual images in a driver's field of view. The image generation unit can be designed, for example, to project a light beam through the projection opening onto the deflecting element, for example in the form of a windshield of the vehicle or a combiner disk. Under a

Polarization changing element may be understood as an optical device configured to change a polarization or phase of a light beam. The polarization changing element may be, for example, as

Delay plate or foil, also called retarder, be realized.

For example, the polarization changing element may be configured to convert between linear and circular polarization or between linear and elliptical polarization. A polarizing filter, also referred to as a polarizing filter, can be understood to mean an optical component which is designed to filter out a light beam with a specific polarization from non-partially or partially polarized light beams. For example For example, the polarizing filter may be configured to filter out a light beam by selective absorption. In particular, the polarization filter can be realized as a linear polarization filter. Depending on the embodiment, the

Polarization change element and the polarization filter in one

Layer composite, such as a composite film, be combined with each other. Thus, a retarder principle is used, in which according to one embodiment, an integration of polarizer and retarder is realized in a cover glass or glare trap of the head-up display. According to one embodiment, the second direction of polarization is that which passes through the polarization filter so that the display beam is first rotated in polarization and then passes through the filter in the second polarization.

The approach presented here is based on the knowledge that through the

Combination of a polarization changing element and a

Polarization filter in a cover for a head-up display, especially in a head-up display with mirrored directly on a windshield display surface, sunlight reflections in the head-up display in direct sunlight can be avoided. This can prevent a viewer from being dazzled while viewing the head-up display.

Such a covering element for suppression of sunlight reflections for head-up displays offers the advantage that, depending on the embodiment, elements such as microlens arrays that have a superficial

Have residual reflection, for example due to a curved surface that can reflect light scattered in a small amount of sunlight in different directions, can be used in an optical system of the head-up display. By virtue of the fact that by means of the cover element in particular sunlight reflections can be avoided in the case of a directly mirrored display surface onto which sunlight radiates from wide angular ranges, it is possible, for example, to realize the head-up display as an autostereoscopic display based on microlens arrays.

According to one embodiment, the polarization changing element may be configured to detect the polarization between a circular polarization as first polarization type and a linear polarization to change as a second polarization. In this case, the polarization filter for a linearly polarized light beam can be transmissive. According to one embodiment, the light rays radiating from the display are initially circularly polarized, are then linearly polarized by the retarder and then pass the linear one

Polarizing filter. By means of this embodiment it can be achieved that only linearly polarized light beams reach the field of view of the observer.

According to a further embodiment, the

Polarization change element and, additionally or alternatively, the

Polarization filter may be formed to polarize a light beam originating from the imaging unit such that the linear polarization when hitting another optical element has both oscillation components perpendicular and parallel to the plane passing through the light beam incident on the optical element and the surface normal of the optical element optical element is clamped at the point of impact. The optical element may be, for example, the windshield of the vehicle or a combiner disc.

Thus, the polarization changing element and / or the polarizing filter may be formed to polarize the light beam substantially perpendicular, parallel or at a defined angle obliquely to the plane of incidence of a radiation direction of the light beam. According to one embodiment, the system allows one degree of freedom in the orientation of the linear polarization of the image beams on the windshield or a combiner for the same mode of operation of the sun-reflex suppression. For example, this linear polarization may be oriented completely perpendicular to the plane of incidence to allow high reflection even at angles close to the Brewster angle. Alternatively, an orientation with portions perpendicular and parallel to the plane of incidence can be realized by a polarization direction rotated in comparison thereto. Linearly polarizing sunglasses often completely out-polarized polarized light, therefore, the system can be deliberately designed with a parallel portion. By this embodiment, the reflection of the light beam at the Windshield be improved. Furthermore, this makes it possible to use the head-up display with special, linearly polarizing sunglasses.

It is advantageous if the cover element is formed in order to direct a light beam striking a surface of the cover element facing the deflecting element into a light trap. A light trap may be understood to mean an element for absorbing light rays. For this purpose, the light trap can be realized for example with a black, matte surface. As a result, disturbing light reflections in the field of view of the observer can be prevented.

Furthermore, the polarization changing element may be realized as a h / A retardation film. The λ / 4 retardation film may be configured to polarize beams of light polarized parallel to a component-specific axis by a quarter wavelength relative thereto

To delay light rays. Thus, it is possible, for example, to convert linearly polarized light beams into circular or elliptically polarized light beams or vice versa. According to a further embodiment, the

Polarization change element and the polarization filter can be realized as a layer composite. This allows a simple and inexpensive production of the cover. The approach proposed here also creates a head-up display for

A vehicle, the head-up display comprising: an image forming unit; a projection opening arranged in a beam path between the image forming unit and a deflecting element of the vehicle; and a cover member according to any one of the above embodiments for covering the projection opening. According to one embodiment, the head-up display can be realized with a light trap. In this case, the cover element may be formed in order to direct a light beam striking a surface of the cover element which faces the deflecting element into the light trap. As a result, disturbing light reflections in the field of view of the observer can be effectively prevented.

According to a further embodiment, the light trap on the

Cover be arranged. This allows a particularly effective suppression of light reflections.

The approach described herein further provides a method of directing light through a cover member according to any one of the preceding embodiments, the method comprising the steps of:

Changing a polarization of one in the beam path between the

Image forming unit and the deflecting element guided light beam between the first polarization and the second polarization; and

Passing a polarized in the second polarization in a predetermined polarization direction of light beam through the polarizing filter.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. It shows:

Fig. 1 is a schematic representation of a head-up display;

FIG. 2 shows a schematic illustration of an autostereoscopic head-up display; FIG.

3 is a schematic representation of an autostereoscopic head-up display based on a parallax barrier;

4 is a schematic representation of an autostereoscopic head-up display based on a microlens array; 5 is a schematic representation of a head-up display according to an embodiment;

FIG. 6 shows a schematic illustration of a head-up display from FIG. 5; FIG.

FIG. 7 shows a schematic representation of a head-up display from FIG. 5; FIG.

Fig. 8 is a schematic representation of a head-up display with

Slatted cover;

FIG. 9 shows a schematic illustration of a head-up display from FIG. 8; FIG.

10 a schematic representation of a head-up display with a lamellar structure lying on a display surface; and

11 is a flowchart of a method for passing light through a cover according to an embodiment.

In the following description of favorable embodiments of the present invention are for the in the various figures

represented and similar elements acting the same or similar

Reference numeral used, wherein a repeated description of these elements is omitted.

1 shows a schematic representation of a head-up display 100. The head-up display 100 is installed in a vehicle 102 and comprises an imaging unit 104 and a head-up display optics 106 for projecting one of the imaging unit 104 generated light beam in a driver's eye 108 of a driver of the vehicle 102nd

Current head-up displays can be designed to image an image plane of the image generator unit 104, or PGU, by means of a corresponding head-up display optics 106 onto a virtual image located in front of the vehicle 102. As a result, the driver increases the image generated by the imaging unit 104. This picture can with be superimposed on a driving scene and are located at a defined distance to a serving as a screen front screen on a virtual screen 110. As an imaging element in the imaging unit 104 can

For example, an LCD module can be used.

As already mentioned, the illustrated virtual image is an enlarged image of the image generated by the imaging unit 104. Therefore, the head-up display optics 106 should have a certain magnification. The required magnification increases with the distance of the virtual screen 110, i. That is, the image generated by the imaging unit 104 should be increased in size so as to be able to occupy the desired field of view of the driver at a greater distance. The distance of the virtual screen 110 in current head-up displays is for example about 15 m.

In an autostereoscopic head-up display system, separate partial images for the left and right eyes and thereby a 3-D effect are generated, as described below with reference to FIG. 2.

FIG. 2 shows a schematic representation of an autostereoscopic head-up display 100. Shown is a basic mode of operation of the

autostereoscopic head-up displays 100. In contrast to the head-up display described with reference to FIG. 1, the head-up display 100 according to FIG. 2 is designed to have separate partial images for a left eye 200 and a right eye 202 to create. For example, the two partial images are already generated by the imaging unit 104. Via the head-up display optics 106, the light of the partial images is then made available to the respective eye in a smaller eyebox.

In such an autostereoscopic approach, it is necessary for the two left and right eye partial images to be emitted in different directions on the display of the imaging unit 104 in order to be able to be supplied to the respective eye via the head-up display optics 106.

To separate the image information, the display can be divided, for example, into different areas for both eyes. Every eye then sees only on certain parts of the display, which are distributed, for example, strip-shaped on the display axis. Such a division can be realized for example by means of a so-called parallax barrier, as described below with reference to FIG. 3.

FIG. 3 shows a schematic representation of an autostereoscopic head-up display 100 based on a parallax barrier. Here, an LCD display 300 is provided at a short distance with a strip-shaped barrier layer 302, which shields certain display areas for one eye. Through the barriers, the two eyes look at different strip-shaped areas of the

Displays 300. These areas are now used to represent different partial images for the two eyes. The eyes can be offered so different partial images. A similar approach is to mount an array of cylindrical microlenses on an LCD module. The principle is illustrated in FIG. 4 and operates similarly to the principle shown in FIG. The respective eye sees only certain strip-shaped areas of the display via the microlenses. Due to this spatial separation, different partial images for both eyes can be displayed.

4 shows a schematic representation of an autostereoscopic head-up display 100 based on a microlens array 400. Shown is a

Functional principle of a head-up display 100, in which the microlens array 400 is arranged in front of a flat LCD screen 402. Due to the microlenses, the respective eye sees only certain areas of the display 402, which then represent the respective partial image. The microlenses are placed as cylindrical lenses over the entire display surface, resulting in strip-shaped areas for each field.

5 shows a schematic representation of a head-up display 500 according to an exemplary embodiment. The head-up display 500 is installed in a vehicle 502 and comprises an image generation unit 504, here a display, and a cover element 506 for covering a projection opening 508 of the head-up display 500. The projection opening 508 is in an optical path between the image forming unit 504 and a deflecting element 510 of the vehicle 502. The deflecting element may be, for example, the windscreen of the vehicle or a

Combiner disc act. For example, the projection opening 508 is formed in a dashboard of the vehicle 502. The

Image forming unit 504 is designed to irradiate a light beam 512 in the beam path.

The cover member 506 is realized with a polarizing filter 514 and a polarization changing element 516 disposed between the polarizing filter 514 and the image forming unit 504. Shown is an exemplary system configuration of the head-up display 500 with the retarder integrated in the cover element 506 as the polarization-changing element 516

Polarization change element 516 is designed to allow a polarization of the light beam 512 coming from the image generation unit between a first polarization mode, in this case a circular polarization, and a second polarization

Polarization, here a linear polarization to change. The polarizing filter 514 is designed to pass only those light beams that are in the second polarization in a predetermined polarization direction, according to FIG. 5 so linearly polarized with a defined orientation direction. The

Polarization types and polarization directions of the light beam 512 are indicated by arrows.

The polarizing filter 514 and the polarization changing element 516 are combined, for example, in a layer composite.

According to an embodiment, the cover member 506 includes a retardation layer as a polarization changing element 516 in combination with a linear polarizing filter 514

for example, sunlight on the way back from the head-up

Display 500 come out to be filtered out. This leads among other things to the following. With a display polarization adapted to the system, the sunlight can be filtered out without influencing the useful light of the imaging unit 504, ie, without affecting the system efficiency. By a corresponding design of the cover 506, the concept can be advantageously integrated into existing systems, so that a basic adaptation of a design process can be omitted.

For example, the linear polarization direction of the light beam 512 directed to the viewer is freely selectable in the system structure. For example, after passing through the polarizing filter 514, the light beam 512 may have a diagonal polarization direction that is substantially at 45 degrees to the plane of incidence of the light beam 512, that of the incident beam 512 and that of the reflected beam on the axis 518 is stretched towards the eye 520. As a result, a displayed virtual image 522 can be prevented from being filtered out by a pair of sunglasses having a horizontal linear polarizing filter.

Important here is the orientation of the linear polarization to the plane of incidence. So that the light beam 512 has equally parallel and vertical components, it should be oriented 45 ° to the plane of incidence. Thus, the double arrows in Fig. 5 according to one embodiment to be understood such that the linear

Polarization points into the drawing plane. In this case, that would be a pure s-polarization, which is not adapted to the polarizing sunglasses.

Provided that the head-up display 500 for reasons of sealing a head-up display space has a cover anyway, such as a cover plate, no additional space is required to implement the approach described here.

In particular, the cover element 506 is suitable for integration into a system with a display mirrored directly over the deflecting element 510. Thus, a structure with a greatly reduced space is made possible. According to one embodiment, the head-up display 500 is realized with a retarder concept in which the head-up display 500

final cover member 506, a linear polarizing filter 514 and a λ / 4 retardation film are integrated as a polarization changing element 516. In Fig. 5, the operation of such a system is illustrated. Shown is a variant with directly above the windshield 510 mirrored display. The display of the imaging unit 504 radiates in circular polarization. The circular polarization is indicated in Fig. 5 with a round arrow. After the passage of the useful light in the form of the light beam 512 through the polarization changing element 516, the useful light is linearly polarized and thus can pass through the polarizing filter 514 unhindered. The linear polarization of the light beam 512 is characterized by oblique double arrows.

The polarization filter 514 and the polarization-changing element 516, which are implemented as layers, for example, are positioned so that the continuous useful light has a freely defined linear polarization direction. This makes it possible, for example, a perpendicular with respect to the plane of incidence linear polarization to maximize reflection at the

Windscreen 510 or to realize a diagonally lying in space linear polarization direction, by the filtering of the image 522 is prevented by a linearly polarized sunglasses.

FIG. 6 shows a schematic representation of a head-up display 500 from FIG. 5. Shown is a function of a special, in this case concave form of the FIG

Covering element 506, through which out of the range of a head position of

Observers outgoing light rays via a reflection on a windshield 510 facing surface of the cover 506 are directed into a light trap 600. The shape of the cover member 506 is designed, for example, such that surface reflections on the

Covering element 506 itself be avoided by the coming of the area of the viewer light beams on the reflection on the

Cover 506 are passed into the light trap 600. The viewer thus looks indirectly into the light trap 600, for example, a dull black

Surface has. This will be dazzling in the reverse beam path Sun rays excluded, ie, it prevents the

Sun rays on the cover 506 reach the eye 520 of the viewer.

According to this embodiment, the light trap 600 is at one of

Viewer facing away edge of the cover 506 attached.

FIG. 7 shows a schematic representation of a head-up display 500 from FIG. 5. FIG. 7 shows the mode of functioning of the filtering out of the sunlight by the cover element 506. In this case, an incoming unpolarized light beam 700 is polarized by the polarization filter 514, in this case a linear filter. After a first pass through the

Polarization changing element 516, the light beam 700 is circularly polarized. Upon reflection on a display surface of the image forming unit 504, the circularly polarized light beam 700 is rotated in its circulating direction so as to have a linear polarization crossed with respect to polarization in the first pass after a second pass through the polarization changing element 516. Thus, the light beam 700 is blocked by the polarizing filter 514.

The light beam 700 is, for example, irradiated, initially unpolarized sunlight, which is linearly polarized during the first pass through the polarizing filter 514. This linearly polarized sunlight is circularly polarized on the first pass through the polarization changing element 516 and then impinges on the display surface of the image forming unit 504.

When reflecting on the display surface, the direction becomes circular

Polarization reversed by a phase jump. After another pass through the polarization changing element 516, the sunlight is again linearly polarized. The linear polarization is now crossed to

Polarization direction of the polarizing filter 514, whereby the sunlight is finally filtered out. The cover 506 may design dependent in systems with

additional imaging mirrors are used and is suitable for stereoscopic and non-stereoscopic head-up displays. FIG. 8 shows a schematic illustration of a head-up display 500

Slatted cover. The head-up display 500 is constructed similarly to the head-up display described above with reference to FIGS. 5 to 7, with the difference that the cover element 506 has a lamellar structure 800 instead of the polarization filter and the polarization change element.

Due to the lamellae adapted to the transmitted image beams

Lamellar structure 800 will be light rays outside of one of the

Image unit 504 blocked angle range, whereby dazzling sunlight reflections are prevented. The shape of the

Blade-like cover member 506 may be similar to a conventional one

Cover be chosen so that the cover 506 itself causes no disturbing back reflections. Thereby, the image forming unit 504 may have any emission polarization. So can from the

Image forming unit 504 emitted light beams, for example

be unpolarized, creating negative effects, such as those in the

Considering a head-up display caused by polarizing sunglasses can be avoided.

FIG. 8 shows a system structure with integrated cover element 506

Slats are shown that are shaped to only a specific one

Transmit angular range in which the payload image the cover member 506 radiates. Beams outside this angular range hit the integrated blades and are thus blocked. According to one embodiment, the head-up display 500 is a

Lamella cover realized, in which the lamellas are formed, in order to let happen like with a Venetian blind only light from certain angles. FIG. 8 illustrates the principle analogous to FIG. 6. The lamellae are oriented in such a way that the angular range of the image beams generated by the head-up display 500 can pass through the cover element 506. The shape of the Cover member 506 is chosen so that surface reflections do not dazzle the viewer.

FIG. 9 shows a schematic illustration of a head-up display 500 from FIG. 8. The functional principle of a removal of a light beam 900 incident through the windshield 510 is shown by means of a

Cover element 506 with integrated lamellar structure 800. In this case, light beams are blocked directly outside of the angular range transmitted by the lamellae. Light rays within the angular range are reflected on the display surface of the image forming unit 504 and again hit outside of an acceptance angle on the cover member 506, whereby they are also blocked.

FIG. 9 shows, for example, a system behavior in the case of the irradiation of sunlight. Sunbeams that radiate outside the acceptance angle of the slats are blocked immediately. Sunbeams within the acceptance angle are reflected on the display surface and then meet outside the acceptance angle again on the lamellar structure 800, where they are also blocked.

10 shows a schematic representation of a head-up display 500 with a lamellar structure lying on a display surface. In contrast to a head-up display described above with reference to FIGS. 5 to 9, the head-up display 500 according to FIG. 10 is realized without a cover element. Instead, the display surface of the image forming unit 504 has a fin sheet 1000 having a louver structure.

Shown is a system structure of the head-up display 500 with a lying directly on a mirrored display surface lamellar structure. The

Functional principle of the suppression of sunlight resembles, for example, the operating principle shown in Fig. 9. To surface reflections on the

To avoid lamellar foil 1000, the lamellar foil 1000 is optionally provided with a comb structure 1002, which, for example, blackened on one side

Has structures. The display slats are realized for example as a freestanding grid with narrow webs or integrated in a film or a glass layer. Direct application of such a lamellar structure to the display surface offers the following advantages.

On the one hand, the display used can have any emission polarization and therefore also be unpolarized, for example, as a result of which negative effects, such as when wearing a polarizing sunglass in the

Connection with a head-up display can be avoided.

When using sufficiently stable display structures can on the

Can be dispensed cover, whereby the space required for the head-up display 500 space can be significantly reduced.

FIG. 10 illustrates by way of example a system in which the display of the imaging unit 504 is reflected directly over the windshield 510. The lamellar film 1000 is additionally coated with the comb structure 1002, whose segments are bevelled. The beveled segments on the display prevent light from being directed towards the driver's eye 520 by direct reflections on the surface. The segments of the comb structure 1002 are, for example, blacked out on one side.

The comb structure 1002 may have the same periodicity as the louvers applied over the display. Alternatively, the segments may be arranged at a smaller or greater distance than the slats to each other. The individual lamellae can be embedded in a foil or glass structure. As an alternative to the lamellae embedded in a substrate, the display may have a freestanding lamellar structure. In this case, no additional comb structure is required on the lamellar substrate. The lamellar structure can, for example, with a preceding with reference to the figures 5 to 7

described covering element to protect the lamellar structure from dust and direct mechanical influences. The freestanding lamellar structure can be realized for example from thin metallic webs, for example in combination with transversely stabilizing webs.

11 shows a flowchart of a method 1100 for conducting light through a cover element according to an exemplary embodiment. The method 1100 may be performed, for example, using a cover member described above with reference to FIGS. 5 to 7. Here, in a step 1110 by means of the polarization changing element, a polarization of a guided in the beam path between the image forming unit and the windshield between the first light beam

Polarization and the second polarization changed. In a further step 1120, a light beam polarized in the second polarization mode in a predetermined polarization direction is transmitted through the polarization filter.

If an exemplary embodiment comprises a "and / or" link between a first feature and a second feature, then this is to be read so that the embodiment according to one embodiment, both the first feature and the second feature and according to another embodiment either only first feature or only the second feature.

Claims

claims

A cover member (506) for covering a projection opening (508) of a head-up display (500) for a vehicle (502), wherein the

Projection opening (508) in the assembled state of the head-up display (500) in a beam path between an image forming unit (504) of the head-up display (500) and a deflecting element (510) is arranged, wherein the cover member (506) the following

Characterized by: a polarization changing element (516) configured to change a polarization of a light beam (512) guided in the beam path between a first polarization mode and a second polarization mode; and a polarizing filter (514) permeable to a light beam (512) polarized in the second polarization direction in a predetermined polarization direction, the polarization filter (514) being mounted in a mounted state of the cover member (506) on a side of the polarization change element (516) remote from the image generation unit (504) ) is arranged.

2. Covering element (506) according to claim 1, wherein the

Polarization changing element (516) is formed to the

Polarization between a circular polarization as the first

Polarization and a linear polarization as the second

Polarization type, wherein the polarizing filter (514) for a linearly polarized light beam (512) is permeable.

3. Covering element (506) according to one of the preceding claims, wherein the polarization changing element (516) and / or the Polarizing filter (514) is adapted to the light beam (512) substantially perpendicular or at a defined angle to

Plane of incidence of the light beam (512) to polarize.

A cover member (506) according to any one of the preceding claims, wherein the cover member (506) is formed so as to have a surface thereof facing the deflecting member (510)

Covering element (506) incident light beam in a light trap (600) to direct.

Cover element (506) according to one of the preceding claims, in which the polarization change element (516) is realized as a Κ / Λ retardation film.

A cover member (506) according to any one of the preceding claims, wherein the polarization changing element (516) and the

Polarization filter (514) are realized as a layer composite.

A head-up display (500) for a vehicle (502), the head-up display (500) comprising: an image generation unit (504); a projection aperture (508) disposed in an optical path between the image forming unit (504) and a deflecting element (510) of the vehicle (502); and a cover member (506) according to any one of the preceding

Claims for covering the projection opening (508).

A head-up display (500) according to claim 7, including a light trap (600), wherein the cover member (506) is formed to provide a surface of the body facing the deflecting member (510)

Covering element (506) incident light beam in the light trap (600) to direct. The head-up display (500) of claim 8, wherein the light trap (600) is disposed on the cover member (506).

A method (1100) for directing light through a cover member (506) according to any one of claims 1 to 6, wherein the method (1100) comprises the steps of:

Changing (1110) a polarization of a light beam (512) guided in the beam path between the image generation unit (504) and the deflecting element (510) between the first polarization mode and the second polarization mode; and

Passing (1120) a light beam (512) polarized in the second polarization mode in a predetermined polarization direction through the polarization filter (514).