DE202021004160U1 - Projection arrangement for a head-up display - Google Patents

Abstract

Comprising a projection arrangement for a head-up display (HUD).
• a substrate (GS1, GS2) with a HUD area (B), and
• a projector (4) aimed at the HUD area (B),
• where the radiation of the projector (4) is predominantly p-polarized,
• wherein the substrate (GS1, GS2) is provided with a reflective coating (20) which is suitable for reflecting p-polarized radiation,
• wherein a foil (F) which is suitable for reflecting p-polarized radiation is arranged adjacent to the reflective coating (20) at a distance of less than 0.85 mm, and
• an intermediate layer (ZS) being arranged between the film (F) and the reflective coating (20).

Description

The invention relates to a projection arrangement for a head-up display.

Modern automobiles are increasingly being equipped with so-called head-up displays (HUDs). With a projector, typically in the area of the dashboard, images are projected onto the windshield, reflected there and perceived by the driver as a virtual image (seen from the driver) behind the windshield. In this way, important information can be projected into the driver's field of vision, for example the current driving speed, navigation or warning information, which the driver can perceive without having to take his eyes off the road. Head-up displays can thus make a significant contribution to increasing traffic safety.

HUD projectors operate predominantly with s-polarized radiation and illuminate the windshield at an angle of incidence of approximately 65%, which is close to Brewster's angle for an air-to-glass transition (57.2° for soda-lime glass). The problem arises that the projector image is reflected on both external surfaces of the windshield. As a result, in addition to the desired main image, a slightly offset secondary image also appears, the so-called ghost image (“ghost”). The problem is usually alleviated by angling the surfaces, particularly by using a wedge-type interlayer to laminate the laminated windshields so that the main image and ghost image can overlay one another. For example, laminated glasses with wedge foils for HUDs are out WO2009/071135A1 , EP1800855B1 or EP1880243A2 known.

Wedge foils are expensive, so producing such a composite panel for a HUD is quite costly. There is therefore a need for HUD projection arrangements that make do with windshields without wedge foils. For example, it is possible to operate the HUD projector with p-polarized radiation, which is not significantly reflected on the pane surfaces. Instead, the windshield has a reflective coating as a reflective surface for the p-polarized radiation. the DE102014220189A1 discloses such a HUD projection arrangement which is operated with p-polarized radiation. Among other things, a single metallic layer with a thickness of 5 nm to 9 nm, for example made of silver or aluminum, is proposed as the reflective structure. Also the WO2019046157A1 discloses a HUD with p-polarized radiation using a reflective coating with at least two metallic layers.

US2017242247A1 discloses another HUD projection arrangement with a reflective coating for p-polarized radiation. The reflective coating can contain one or more conductive silver layers, but can also have dielectric layers. However, the reflection spectrum has a clearly curved shape in the relevant spectral range, so that the degree of reflection is relatively strongly dependent on wavelength. This is disadvantageous with regard to a color-neutral representation of the HUD projection.

CN 204 143 067 U discloses a HUD system comprising a laminated glass consisting of two panes of glass which are connected to one another via an intermediate layer. The laminated glass has a transparent nanolayer that includes a number of dielectric layers and at least one metallic layer.

There is a need for projection arrangements for HUDs with reflective coatings that ensure high transmission in the visible spectral range and have high reflectivity for p-polarized radiation and allow a color-neutral display. The object of the present invention is to provide such an improved projection arrangement.

The object of the present invention is achieved according to the invention by a projection arrangement according to claim 1. Preferred embodiments emerge from the dependent claims.

According to one embodiment of the invention, a projection arrangement for a head-up display is provided. The projection assembly includes a substrate having a HUD area and a projector directed at the HUD area. The radiation from the projector is predominantly p-polarized and the substrate is provided with a reflective coating that is suitable for reflecting p-polarized radiation. Furthermore, adjacent to the reflective coating is a foil at a distance of less than 0.85 mm (e.g. 0.7 mm, 0.84 mm, 0.78 mm, 0.7 mm, 0.55 mm, 0.51 mm, 038 mm or 100 µm) which is also suitable for reflecting p-polarized radiation.

This ensures high transmission in the visible spectral range, which has both high reflectivity for p-polarized radiation and allows a color-neutral display.

According to the invention, an intermediate layer is arranged between the film and the reflective coating. Such an arrangement can be incorporated into common manufacturing processes—for example for composite panes—so that they can be implemented cost-effectively.

According to a development of the invention, the distance between the reflective coating and the film is 25 μm or less.

This has advantages for typical angles of the projector to the projection surface, since the possible formation of ghost images is kept to a minimum.

According to a development of the invention, the radiation from the projector is essentially purely p-polarized.

As a result, the radiation provided by the projector can be used advantageously for reflection.

According to a development of the invention, the radiation from the projector strikes the substrate at an angle of incidence of 55° to 70°.

As a result, the area around the Brewster angle can be used particularly well.

According to a development of the invention, the reflective coating has a geometric thickness of 5 nm to 700 nm (e.g. also 10 nm to 14 nm).

According to a development of the invention, the reflective coating is arranged between the first substrate and a second substrate.

That is, the invention can also be used with laminated glass panes.

In a further embodiment of the invention, a substrate arrangement for use in a projection arrangement for a head-up display is provided. The substrate assembly includes a substrate having a HUD area, the substrate being provided with a reflective coating capable of reflecting p-polarized radiation; a foil suitable for reflecting p-polarized radiation being arranged adjacent to the reflective coating at a distance of less than 0.85 mm (e.g. 0.7 mm or 100 µm).

This ensures high transmission in the visible spectral range, which has both high reflectivity for p-polarized radiation and allows a color-neutral display.

According to a development of the invention, the reflective coating is arranged between the first substrate and a second substrate.

That is, the invention can also be used with laminated glass panes, in particular vehicle windshields.

character list

The invention is explained in more detail below with reference to drawings and exemplary embodiments. The drawings are schematic representations and not to scale. The drawings do not limit the invention in any way.

• 1 eine Draufsicht auf eine Substratanordnung einer beispielhaften Ausführungsform der Erfindung,
• 2 einen Querschnitt durch eine erfindungsgemäße Projektionsanordnung, und
• 3 eine schematische Schnittdarstellung durch Schichten einer erfindungsgemäßen Substratanordnung zur Verwendung in einer erfindungsgemäßen Projektionsanordnung, und
• 4 eine weitere beispielhafte Schnittdarstellung durch Schichten einer erfindungsgemäßen Substratanordnung zur Verwendung in einer erfindungsgemäßen Projektionsanordnung.

Show it:

• 1 a plan view of a substrate arrangement of an exemplary embodiment of the invention,
• 2 a cross section through a projection arrangement according to the invention, and
• 3 a schematic sectional view through layers of a substrate arrangement according to the invention for use in a projection arrangement according to the invention, and
• 4 a further exemplary sectional view through layers of a substrate arrangement according to the invention for use in a projection arrangement according to the invention.

Detailed presentation of the invention

In the following the invention will be illustrated in more detail with reference to the figures. It should be noted that different aspects are described, which can be used individually or in combination. That is, each aspect can be used with different embodiments of the invention unless explicitly presented as purely alternative.

Insofar as standards, specifications or the like are named in this application, at least the standards, specifications or the like applicable on the filing date are referred to. This means that if a standard/specification etc. is updated or replaced by a successor, the invention can also be applied to this.

Various embodiments are shown in the figures.

An embodiment of the invention relates to a projection arrangement for a head-up display HUD. Such is an example in 1 and 2 sketched.

There, by way of example, a substrate arrangement 10 (eg a windshield of a land vehicle, sea vehicle, air vehicle or spacecraft) with a HUD area B of the substrate arrangement 10 is shown. The windshield as an example of a substrate arrangement according to the invention has an upper edge O and a lower edge U. The substrate arrangement can have one substrate GS1 or several substrates GS1, GS2.

The projection arrangement also includes a projector 4, which is directed onto an area of the substrate arrangement. In this area, which is usually referred to as HUD area B, images can be generated by the projector 4, which are perceived by a viewer 5 (vehicle driver) as virtual images on the side of the substrate arrangement facing away from him when his eyes are inside the so-called Eyebox E.

The substrate arrangement 10 is made up of an optional second substrate GS2, which is an outer pane in a laminated glass pane, for example, and a first substrate GS1, which is an inner pane in a laminated glass pane, for example, which are connected to one another via a thermoplastic intermediate layer 3. The bottom edge U of the substrate assembly 10 is positioned downward toward the engine of the passenger car, the top edge O of the substrate assembly 10 upward toward the roof. In the installed position, the substrate GS2 faces the outside environment, and the substrate GS1 faces the vehicle interior.

The substrate GS2 and the substrate GS1 are made of soda-lime glass, for example. Of course, the substrates GS1, GS2 can also be formed from other glass or polymeric plastic materials, in particular from different materials.

The substrate GS2 has a thickness of 2.1 mm, for example, and the substrate GS1 has a thickness of 1.6 mm or 2.1 mm. The intermediate layer 3 can be formed from a PVB film, for example. Typical thicknesses for the intermediate layer 3 are in the range of approximately 0.76 mm-0.85 mm, or less than 0.55 mm, in particular in the range of 0.38 mm-0.51 mm, or in particular even thinner thinner than <100 µm. The intermediate layer 3 has an essentially constant thickness, apart from any surface roughness that is customary in the art—it is not designed as a so-called wedge film.

That is, a HUD area B is formed on a substrate GS1, onto which a projector 4 is directed during operation.

According to the invention, the radiation of the projector 4 is predominantly p-polarized, in particular essentially purely p-polarized.

Since the projector 4 irradiates the substrate arrangement 10 at an angle of incidence of approximately 55°-70°, which is close to Brewster's angle of 57.2°, the radiation from the projector is reflected only insignificantly at the external surfaces I, IV of the substrate arrangement 10 . P-polarized radiation has the advantage over s-polarized radiation that the reflection coefficient is almost 0 in the Brewster angle range (e.g. 45°-73°).

The reflective coating 20 ( 3 ) on the other hand is optimized for the reflection of p-polarized radiation. It serves as a reflection surface for the radiation from the projector 4 for generating the HUD projection. Furthermore, the reflection coating according to the invention can possibly additionally serve as an IR-reflecting coating.

Furthermore, adjacent to the reflective coating 20 is a foil F at a distance of less than 0.85 mm (e.g. 0.84 mm, 0.78 mm, 0.7 mm, 0.55 mm, 0.51 mm, 038 mm or 100 µm) arranged, which is suitable for reflecting p-polarized radiation. The only important thing is that the thickness is so small that it is below the resolving power for the human eye. Typical HUD systems have an image range of more than one meter, typically in the range of 1.8 m to 15 m. In this range it can be assumed that the angular resolution corresponds to 1'. 1' is equivalent to 0.29 mrad (0.58 mm for a 2 m image distance, 1.45 mm for a 5 m image distance and 2.90 mm for a 10 m image distance).

This ensures high transmission in the visible spectral range, which has both high reflectivity for p-polarized radiation and allows a color-neutral display.

In other words, unlike in the prior art, both a reflective coating 20 and a film F are used here, each of which reflects p-polarized radiation particularly well.

Advantageously, when the layers are close together, the joint image produced by reflection from the foil F and by reflection from the reflective coating 20 appears as a joint image. This is always the case when the superimposed images have a deviation in the eye of the viewer 5 that is less than the resolving power of the eye.

In addition, while in the prior art small fluctuations in the thickness of elements of the substrate arrangement can be perceived as waviness, this waviness becomes less noticeable if images of the reflective coating 20 and the film F are superimposed. The reason for this is that the reflective coating 20 and the film F generally have different ripples or because the difference in brightness that can be perceived as ripples is less pronounced as a result of the superimposition of two images.

This ensures high transmission in the visible spectral range, which has both high reflectivity for p-polarized radiation and allows a color-neutral display.

According to the invention, an intermediate layer ZS is arranged between the foil F and the reflection coating 20 .

The intermediate layer ZS between the film F and the reflection coating 20 contains at least one substance selected from the group comprising polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyvinyl chloride (PVC), polyvinyl fluoride (PVF), Polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyacrylate (PA), polymethyl methacrylate (PMMA), polyurethane (PUR), and/or mixtures and copolymers thereof.

Such an arrangement can be integrated into common manufacturing processes - e.g. for composite panes - so that they can be implemented cost-effectively.

According to a development of the invention, the distance between the reflective coating 20 and the film F is 25 μm or less. The thickness depends on the projection distance. As the projection distance increases, so can the thickness.

This has advantages for typical angles of the projector to the projection surface, since the possible formation of ghost images is kept to a minimum.

According to a development of the invention, the radiation of the projector 4 is essentially purely p-polarized.

As a result, the radiation provided by the projector can be used advantageously for reflection.

According to a development of the invention, the radiation from the projector 4 strikes the substrate GS1 at an angle of incidence of 55° to 70°.

As a result, the area around the Brewster angle can be used particularly well.

According to a development of the invention, the reflective coating 20 has a geometric thickness of 5 nm to 700 nm (e.g. also 10 nm to 14 nm). If a non-metallic coating is used in the wet-coating process, the geometric thickness can also be greater.

According to a development of the invention, the reflective coating is arranged between the first substrate GS1 and a second substrate GS2. As in 3 shown, either the reflective coating 20 can be arranged first in the beam path, then the film (F), or the other way around as in 4 shown, first the film (F) and then the reflective coating 20. Between the second substrate GS1 and the film F, an intermediate layer ZS can also be arranged.

The second substrate GS2 can be made from the same material as the first substrate GS1.

The first substrate GS1 and the second substrate GS2 can be a glass substrate or a plastic substrate, for example. In principle, all electrically insulating substrates that are thermally and chemically stable under the conditions of manufacture and use of the vehicle pane according to the invention are suitable as the substrate.

The glass pane preferably contains glass substrates, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and/or mixtures from that.

An intermediate layer ZS can also be arranged between the second substrate GS2 and the film F.

The intermediate layer ZS between the film F and the second substrate GS2 contains at least one substance selected from the group comprising polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyvinyl chloride (PVC), polyvinyl fluoride (PVF) , polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyacrylate (PA), polymethyl methacrylate (PMMA), polyurethane (PUR), and/or mixtures and copolymers thereof.

That is, the invention can also be used with laminated glass panes, in particular vehicle windshields.

In another embodiment of the invention, a substrate assembly for use in a head-up display (HUD) projection assembly is provided.

The substrate arrangement comprises a substrate GS1 with a HUD area B, the substrate GS1 being provided with a reflective coating 20 which is suitable for reflecting p-polarized radiation; adjacent to the reflective coating 20 at a distance of less than 0.85 mm (e.g. 100 µm) is a foil F suitable for reflecting p-polarized radiation.

This ensures high transmission in the visible spectral range, which has both high reflectivity for p-polarized radiation and allows a color-neutral display.

According to a development of the invention, the reflective coating 20 is arranged between the first substrate GS1 and a second substrate GS2.

That is, the invention can also be used with laminated glass panes, in particular vehicle windshields.

Of course, the layer sequence can also be selected differently depending on the direction of illumination, without loss of generality. It is preferred that the reflective coating 20 is illuminated first and then the film F ( 3 ).

That is, with a substrate GS1, depending on whether the substrate GS1 is to be penetrated by the light from the projector or whether the substrate GS1 is essentially the supporting surface for the film F and the reflection coating 20, the order of film F and the Reflective coating 20 be different.

Of course, without restricting generality, other layers can also be provided on or between the individual layers, or different functions can be integrated into layers already shown. For example, a heating function, sun protection, IR filter or the like can also be provided. In particular, the reflective coating can be provided as a heating layer, sun protection layer or IR filter.

The reflectivity of the coating for p-polarized light is between 2% and 25% (e.g. between 5% and 10%).

In particular, the invention makes it possible for users 5 who wear eyeglasses with a polarization filter, which are usually p-polarized, to be able to perceive the display of a HUD display without restrictions, since the contrast offered between the HUD image and the ambient light is increased by a higher light yield Overlay of two images can be improved.

That is, the invention can be used, for example, in windshields, particularly in laminated glass panes, as an example of a substrate arrangement.

According to a further embodiment of the invention, a vehicle with a projection arrangement according to the invention, in particular a land, sea, air or space vehicle, is provided.

reference list

HUD

Head Up Display (HUD)

GS1

(first) substrate

GS2

(second) substrate

B

HUD area

4

projector

5

viewer

E

eyebox

20

reflective coating

10

substrate arrangement

f

foil

ZS

intermediate layer

O

Above

u

Below

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2009071135 A1 [0003]
• EP 1800855 B1 [0003]
• EP 1880243 A2 [0003]
• DE 102014220189 A1 [0004]
• WO 2019046157 A1 [0004]
• US2017242247A1 [0005]
• CN 204143067 U [0006]

Claims (9)

Comprising a projection arrangement for a head-up display (HUD). • a substrate (GS1, GS2) with a HUD area (B), and • a projector (4) aimed at the HUD area (B), • where the radiation of the projector (4) is predominantly p-polarized, • wherein the substrate (GS1, GS2) is provided with a reflective coating (20) which is suitable for reflecting p-polarized radiation, • wherein a foil (F) which is suitable for reflecting p-polarized radiation is arranged adjacent to the reflective coating (20) at a distance of less than 0.85 mm, and • an intermediate layer (ZS) being arranged between the film (F) and the reflective coating (20). projection arrangement claim 1 , characterized in that the distance between the reflective coating (20) and the film (F) is preferably less than 0.55 mm, particularly preferably less than 100 µm or less than 25 µm. Projection arrangement according to one of the preceding Claims 1 or 2 , wherein the radiation of the projector (4) is essentially purely p-polarized. Projection arrangement according to one of Claims 1 until 3 , wherein the radiation of the projector (4) hits the substrate (GS1) at an angle of incidence of 55° to 70°. Projection arrangement according to one of Claims 1 until 4 , wherein the reflective coating (20) has a geometric thickness of 5 nm to 700 nm. Projection arrangement according to one of Claims 1 until 5 , wherein the reflective coating (20) between the first substrate (GS1) and a second substrate (GS2) is arranged. Projection arrangement according to one of Claims 1 until 6 , characterized in that an intermediate layer (ZS) is arranged between the film (F), the first substrate (GS1) and the second substrate (GS2). Projection arrangement according to one of Claims 1 until 7 , wherein either the reflection coating (20) and then the foil (F) is arranged first in the beam path, or the foil (F) first and then the reflection coating (20) is arranged. Projection arrangement according to one of Claims 1 until 8th , wherein the intermediate layer (ZS) between the film F and the reflective coating (20) comprises at least one substance selected from the group consisting of polybutylene terephthalate (PBT), polycarbonate (PC), polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyvinyl chloride (PVC), Contains polyvinyl fluoride (PVF), polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyacrylate (PA), polymethyl methacrylate (PMMA), polyurethane (PUR), and/or mixtures and copolymers thereof.

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