Display device for a motor vehicle

Abstract

The present invention relates to a display device (10) for a motor vehicle comprising a housing (200) and a transparent cover (300) closing the housing (200), wherein the housing (200) includes an image generation unit (100) and an optical unit (120). The cover (300) has a transparent, removable protective layer (400).

Description

[0001] The present invention relates to a display device for a motor vehicle comprising a housing and a transparent cover closing the housing. The housing includes an image generation unit and an optical unit. Such display devices are used today in almost every motor vehicle, for example, to generate a virtual image for a driver.

[0002] Such a display device projects a virtual image, for example, onto the windshield of a motor vehicle. A display device is understood to be a head-up display, also known as a HUD, which allows the viewer to maintain their line of sight, as the displayed content is superimposed onto their virtual image within their field of vision. To prevent the image projected by the display device from being affected, for example, by dirt or scratches, the transparent cover of the housing, through which the virtual image is projected into the interior of the motor vehicle, has a protective layer, with the surface of the cover usually being coated with a hard coating material (referred to as a hard coating). Display devices with such a coating on the cover are well known to those skilled in the art.

[0003] These are transparent protective films, held in place by an adhesive, designed to protect the surface of an electronic device, specifically the display. The protective film serves to shield the display from scratches, ensuring consistently good readability and functionality. If the protective film becomes scratched over time, it can be peeled off and removed, then replaced with a new self-adhesive protective film.

[0004] Furthermore, devices for protecting surfaces in motor vehicles are known in various embodiments. For example, it is known to apply an adhesive transparent protective film to a vehicle's windshield to effectively protect it against dirt and damage. If the protective film is damaged, it is removed and replaced with a new self-adhesive protective film.

[0005] The disadvantage is that if a protective layer of the cover, in the form of hard coating, is damaged, it cannot be repaired or replaced and the entire display device must be replaced, which results in high costs, especially in complex installation situations.

[0006] The present invention is based on the objective of providing an improved solution for a protective layer of the transparent cover of the housing for the display device, which can be easily and quickly replaced in case of damage.

[0007] This problem is solved according to the invention by a display device according to the preamble of independent claim 1 together with the features of the characterizing part of independent claim 1. Advantageous embodiments can be found in the dependent claims.

[0008] The invention provides for a transparent, removable protective layer instead of a hard coating or a firmly bonded protective layer.

[0009] A particular advantage of the display device according to the invention is that the transparent, removable protective layer protects a surface of the cover while simultaneously preserving the cover's functionality, thanks to the layer's transparency. The protective layer shields the cover from external influences, especially dirt and damage such as impacts and scratches, thus increasing the display device's durability. A further advantage is that the protective layer provides protection against UV rays, the sun's ultraviolet rays. The protective layer prevents surface damage such as fading, including discoloration, and thus extends the cover's lifespan. Furthermore, the transparent, removable protective layer is easy to maintain.

[0010] According to an advantageous embodiment of the invention, the protective layer is a tear-off protection film.

[0011] One advantage is that a tear-off protective film is inexpensive to manufacture and easy to process, allowing it to be easily adapted to the geometry of the display device's surface. The film is also flexible due to its thinness. Another advantage is its unobtrusive appearance, ensuring that the design and function of the display device remain unaffected. Furthermore, a tear-off protective film provides effective protection against damage and helps preserve the original surface of the cover, maintaining the display device's aesthetic appearance over time.In case of damage, such as scratches, to the tear-off protective film, it can be removed and replaced particularly easily and quickly, without incurring further expensive costs for repairing the surface of the cover or even having to replace it completely.

[0012] According to an advantageous embodiment of the invention, the protective layer is a protective glass.

[0013] One advantage is that the protective glass has a higher hardness and therefore greater impact resistance than conventional protective coatings, such as hard coatings, thus protecting against damage. The protective glass also offers the advantage of being removable from the cover for cleaning and then reinstalled, allowing for multiple uses. This makes it possible, for example, to perform complex cleaning processes in an ultrasonic bath. Another advantage is that the surface finish of the protective glass, such as a frosted surface, reduces reflection from incident sunlight.

[0014] According to an advantageous embodiment of the invention, several transparent protective layers are arranged one above the other.

[0015] One advantage is that, due to the multiple layers of protective coating arranged on top of each other, if the surface is damaged, a protective layer can be easily and quickly removed, thus restoring a new, undamaged surface without having to replace the entire display device or individual parts of the display device, or having to painstakingly refinish the damaged surface.

[0016] It has been found that ten protective layers can be arranged particularly well on top of each other and adapted to the geometry of a cover's surface without impairing any function of the display device, such as the cover's transparency. With such a maximum arrangement of protective layers, the optical boundary layer is not affected, and none of the generated light rays used to display the virtual image are lost.

[0017] According to an advantageous embodiment of the invention, a transparent protective layer has a material thickness in a range between 15 µm and 2000 µm, preferably a material thickness of 20 µm.

[0018] It has been found that a transparent protective layer, in particular a tear-off protective film with a material thickness of 20 µm, is particularly easy to manufacture and can be applied to the surface of the cover with exceptional ease, conforming to the surface geometry. At this low material thickness of 20 µm, the protective layer also blends seamlessly into the environment of the display device, making it virtually invisible to the observer. Furthermore, the coating does not impair the functionality of the display device. Protective films with this material thickness are commercially available.

[0019] According to an advantageous embodiment of the invention, the protective layer is attached by means of adhesion.

[0020] Adhesion refers to the adhesion (also known as self-adhesion) of one substance to another without additional adhesive agents.

[0021] One advantage is that the protective layer adheres to the surface of the cover via adhesion, without the use of adhesive. This prevents discoloration or hardening, as can occur with adhesives, which can cause stains on the protective layer or make it impossible to remove the layer from the surface of the cover. Another advantage is that removing and replacing the self-adhesive protective layer from the surface of the cover leaves no residue, such as adhesive residue, that would otherwise need to be removed.

[0022] According to an advantageous embodiment of the invention, the protective layer has a tab.

[0023] One advantage is that the protective layer can be easily and quickly loosened and removed using the tab, especially when the tab is facing the driver.

[0024] It has been found that it is particularly advantageous if the protective layer has a tab in one corner, facing the driver's compartment, towards the center console, making it particularly easy to grip.

[0025] The display device according to the invention is used in the automotive sector. Alternatively, the display instrument according to the invention can also be used in motorcycles, aircraft or ships.

[0026] Further features of the present invention will become apparent from the following description and the attached claims in conjunction with the figures. Advantageous embodiments of the invention will also become apparent from the features of the following description and the figures.

[0027] To better understand 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 identical or equivalently 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 protection of the invention as defined in the appended claims. Figure overview

[0028] They show, in a schematic, sketch-like representation: Fig. 1 a schematic diagram of a display device according to the invention, Fig. 2 a cutaway side view through an embodiment of a display device according to the invention with a protective layer Fig. 3 a cutaway side view through an embodiment of a display device according to the invention with multiple protective layers Fig. 4 An oblique view of an embodiment of several stacked protective layers Character description

[0029] Fig. Figure 1 shows a schematic diagram of a display device 10 according to the invention for a motor vehicle. The display device 10 comprises a housing 200 and a cover 300 closing the housing 200, as well as a mirror unit 500. The housing 200 has an image generation unit 100 and an optical unit 120 arranged inside it.

[0030] A beam of light SB1 originates from an imaging unit 110 and is reflected by a projection surface 111 onto a first mirror 121, and from there onto a second, curved mirror 122. The second, curved mirror 122 reflects the beam of light SB1 again towards the mirror unit 500. The mirror unit 500 is represented here as the windshield 700 of the motor vehicle (not shown). From the mirror unit 500, the beam of light SB2 travels towards the eye 61 of an observer.

[0031] The viewer sees a virtual image VB, which is located outside the vehicle, above the hood or even in front of the vehicle. Through the interaction of optical unit 120 and mirror unit 500, the virtual image VB is a magnified representation of the image coming from the projection surface 111. The virtual image VB symbolically displays a speed limit, the current vehicle speed, and navigation instructions.

[0032] As long as the viewer's eye (800) is within the field of view (600) indicated by a rectangle (eyebox), all elements of the projected virtual image (VB) are visible to the eye. If the eye is outside the field of view (600), the virtual image (VB) is only partially visible or not visible at all. The larger the field of view (600), the less restricted the viewer is in choosing their seating position in the vehicle.

[0033] The second, curved mirror 122 is adapted to the curvature of the windshield 700 and ensures that the image distortion is as stable as possible across the entire field of view 600. The second, curved mirror 122 is rotatably mounted by means of a bearing 123. This rotation of the second, curved mirror 122 allows the field of view 600 to be shifted, thus adjusting its position to the position of the viewer's eye 800.

[0034] The first mirror 121 serves to ensure that the path traveled by the beam SB1 between the projection surface 111 and the second, curved mirror 32 is long, while at the same time the optical unit 120 remains compact.

[0035] The housing 200, in which the image generation unit 100 with the imaging unit 110 and the projection surface 111, as well as the optical unit 120 with the first mirror 121, the second curved mirror 122, and the rotatable bearing 123 are arranged, is separated from the environment and sealed by the cover 300. The elements of the image generation unit 100 and the elements of the optical unit 120 are thus protected, for example, against dust present in the interior of the vehicle.

[0036] The cover 300 also has a transparent, removable protective layer 400 on its upper side facing the mirror unit 500, the windshield 700, to protect against damage, for example scratches, whereby the protective layer 400 can be a tear-off protective film 410 or a protective glass 420.

[0037] Fig. Figure 2 shows a cutaway side view through an embodiment of a display device 10 according to the invention with a protective layer 400, wherein the protective layer 400 in the exemplary embodiment is a tear-off film 410. In an alternative embodiment, the protective layer 400 can also be a protective glass 420. The tear-off film 410 adheres to a surface on the top of the cover 300 by means of adhesion, without adhesive. In an alternative embodiment not shown, the tear-off film 410 is held on the surface of the cover 300 by an electrostatic charge. After being placed on the surface of the cover 300, the tear-off film 410 conforms to the shape of the surface of the cover 300. Thus, no unwanted gaps are formed between the tear-off film 410 and the surface, which would prevent the tear-off film from adhering properly. The same principle applies to a sufficiently thin protective glass 420.

[0038] Fig. Figure 3 shows a cutaway side view through an embodiment of a display device 10 according to the invention with a protective layer 400, wherein the protective layer 400 consists of several stacked protective layers 400. In the preferred embodiment, the stack 900 of protective layers consists of several stacked tear-off protective films 410. In an alternative embodiment, the stack 900 of protective layers can also consist of several stacked protective glass sheets 420. The tear-off protective films 410 are applied as a stack 900 directly onto a surface of the top of a cover 300 of the display device 10.

[0039] The individual tear-off protection films 410 adhere to each other and to the surface of the cover 300 by means of adhesion. In an alternative embodiment not shown, the tear-off protection films 410 adhere to each other and to the surface of the cover 300 by means of an electrostatic charge. The stack of 900 tear-off protection films 410, after being placed on the surface of the cover 300, conforms to a shape of the surface of the cover 300.

[0040] Fig. Figure 4 shows an oblique view of an embodiment of several stacked protective layers 400, wherein the protective layers 400 form a stack 900 with thickness D. In the preferred embodiment, the stack 900 consists of several stacked tear-off protective films 410. In an alternative embodiment, the stack 900 can also consist of several stacked protective glasses 420. It is particularly advantageous if the stack 900 consists of a maximum of ten individual stacked protective layers 400, so that the function of a display device 10, in particular a projection of a virtual image VB, as shown in Figure 4, is possible. Fig. 1 shown, is not affected.

[0041] Polyester is preferably used as the material for the tear-off protection film. The surface of the tear-off protection film 410 is scratch-resistant. This means that the individual tear-off protection films 410 in the stack 900 have a hard surface. The surface hardness of a tear-off protection film 410 is specified using the so-called scratch hardness (pencil hardness) (according to ISO 15184), where, for example, 0H means that the surface is not scratch-resistant, and 5H means that the surface is particularly scratch-resistant. In the preferred embodiment, the tear-off protection film 410 has a surface hardness of 5H.

[0042] A single tear-off protective film 410 typically has a material thickness between 15 µm and 2000 µm, with the tear-off protective film having a material thickness of 20 µm in the preferred embodiment. In an alternative embodiment, not shown, a protective glass has a material thickness of 500 µm.

[0043] Each of the individual tear-off protective films 410 has a tab 430 with a perforation 431, allowing a single tear-off protective film 410 to be detached from the stack D and thus easily removed in case of damage, such as a scratch, without dislodging other tear-off protective films 410 from the stack or even the entire stack D. The tab 430 is preferably triangular in a corner of the tear-off protective film. The perforation makes the tab 430 particularly easy to grasp and the tear-off protective film to be detached. The same principle applies to a protective glass 420.

[0044] Overall, the exemplary embodiment shows how, according to the invention, a display device can be designed in a simple manner with a protective layer according to the invention, so that the display device is protected against, for example, scratching and the display device acquires an additional property without the properties of the display device being restricted by damage in the form of scratching of the surface or even having to be completely replaced. Reference symbol list 10 Display device 100 image generation units 110 Imaging Unit 111 projection surface 120 optical units 121 first mirror 122 second, curved mirror 123 warehouses 200 cases 300 Coverage 400 protective layer 410 Tear-off protection film 420 protective glass 430 tab 431 Perforation 500 mirror units 600 viewing area 700 Windscreen 800 eye 900 stacks SB1 beam bundle SB2 beam bundle VB Virtual Image MS material thickness D thickness of the stack

Claims

[1] Display device (10) for a motor vehicle comprising a housing (200) and a transparent cover (300) closing the housing (200), wherein the housing (200) comprises an image generation unit (100) and an optical unit (120), characterized by , that the cover (300) has a transparent removable protective layer (400). [2] Display device (10) according to claim 1, characterized by , that the protective layer (400) is a tear-off protection film (410). [3] Display device (10) according to claim 1, characterized by , that the protective layer (400) is a protective glass (420). [4] Display device (10) according to any one of the preceding claims 1 to 3, characterized by , that several transparent protective layers (410, 420) are arranged on top of each other. [5] Display device (10) according to any one of the preceding claims 1 to 4, characterized by, that a transparent protective layer (410, 420) has a material thickness (MS) between 15 µm and 2000 µm, preferably a material thickness (MS) of 20 µm. [6] Display device (10) according to any one of the preceding claims 1 to 5, characterized by , that the protective layer (410, 420) is attached by means of adhesion. [7] Display device (10) according to any one of the preceding claims 1 to 6, characterized by , that the protective layer (410, 420) has a tab (420).

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