PROJECTION ARRANGEMENT COMPRISING A COMPOSITE PANE AND P-POLARIZED RADIATION

Abstract

A projection arrangement includes a composite pane including transparent outer and inner panes, a thermoplastic intermediate layer, and a reflection layer, the outer pane having an outer side facing away from the thermoplastic intermediate layer and an inner side facing the thermoplastic intermediate layer and the inner pane has an outer side facing the thermoplastic intermediate layer and an inner side facing away from the thermoplastic intermediate layer, the reflection layer being arranged between the outer and inner panes and reflecting p-polarized light, the reflection layer being opaque or arranged spatially in front of an opaque background when viewed through the composite pane, and an image display device directed at the reflection layer and irradiates it with p-polarized light through the inner pane, wherein the reflection layer reflects the p-polarized light.

Claims

1. A projection arrangement comprising: a composite pane comprising a transparent outer pane, a thermoplastic intermediate layer, a reflection layer, and a transparent inner pane, wherein the outer pane has an outer side facing away from the thermoplastic intermediate layer and an inner side facing the thermoplastic intermediate layer and the inner pane has an outer side facing the thermoplastic intermediate layer and an inner side facing away from the thermoplastic intermediate layer, wherein the reflection layer is arranged between the outer pane and the inner pane and is adapted to reflect p-polarized light, wherein the reflection layer itself is opaque or is arranged spatially in front of an opaque background when viewed through the composite pane proceeding from the inner side of the inner pane, and an image display device that is directed at the reflection layer and irradiates it with p-polarized light through the inner pane, wherein the reflection layer reflects the p-polarized light.

2. The projection arrangement according to claim 1, wherein the reflection layer reflects 30% or more of the p-polarized light incident on the reflection layer.

3. The projection arrangement according to claim 1, wherein the image display device is an LCD display, LED display, OLED display, or an electroluminescent display.

4. The projection arrangement according to claim 1, wherein the opaque background is implemented as at least one masking strip and is arranged in an edge region of the outer pane.

5. The projection arrangement according to claim 4, wherein the at least one masking strip is arranged on the inner side of the outer pane.

6. The projection arrangement according to claim 4, wherein the reflection layer is arranged on the outer side of the inner pane.

7. The projection arrangement according to claim 5, wherein the reflection layer is arranged on the masking strip on the inner side of the outer pane.

8. The projection arrangement according to claim 4, wherein the at least one masking strip is implemented circumferentially in the edge region of the composite pane, and has, in a section that is in overlap with the reflection layer, a greater width than in sections different therefrom.

9. The projection arrangement according to claim 1, wherein the reflection layer is a coated or uncoated film and is arranged within the thermoplastic intermediate layer.

10. The projection arrangement according to claim 1, wherein the reflection layer contains at least one metal.

11. The projection arrangement according to claim 1, wherein the reflection layer consists of a metal-free, reflecting film.

12. The projection arrangement according to claim 10, wherein the reflection layer is applied to the outer pane, the opaque background, the inner pane, and/or a film by a vapor deposition process.

13. The projection arrangement according to claim 1, wherein a high-refractive-index coating with a refractive index of at least 1.7 is arranged at least in a region of the inner side of the inner pane that is in complete overlap with the reflection layer.

14. A method for producing a projection arrangement according to claim 1, comprising: (a) arranging a transparent outer pane, a thermoplastic intermediate layer, a reflection layer, and a transparent inner pane to form a layer stack, wherein the outer pane has an outer side facing away from the thermoplastic intermediate layer and an inner side facing the thermoplastic intermediate layer and the inner pane has an outer side facing the thermoplastic intermediate layer and an inner side facing away from the thermoplastic intermediate layer, wherein the reflection layer is arranged between the outer pane and the inner pane and is adapted to reflect p-polarized light, and wherein the reflection layer itself is opaque or is arranged spatially in front of an opaque background when viewed through the layer stack proceeding from the inner side of the inner pane, (b) laminating the layer stack to form a composite pane, and (c) arranging an image display device that is directed at the reflection layer and irradiates it with p-polarized light through the inner pane, wherein the reflection layer reflects the p-polarized light.

15. A method comprising providing a projection arrangement according to claim 1 in a vehicle for travel on land, in the air, or on water.

16. The projection arrangement according to claim 2, wherein the reflection layer reflects 50% or more of the p-polarized light incident on the reflection layer.

17. The projection arrangement according to claim 3, wherein the image display device is an LCD display.

18. The projection arrangement according to claim 10, wherein the at least one metal is silver.

19. The projection arrangement according to claim 12, wherein the reflection layer is applied to the outer pane, the opaque background, the inner pane, and/or a film by CVD process or PVD process.

20. The method according to claim 15, wherein the composite pane is a windshield.

Description

[0075] The invention is explained in greater detail in the following using exemplary embodiments with reference to the accompanying figures. They depict, in simplified representation, not to scale:

[0076] FIG. 1 a cross-sectional view of an exemplary embodiment of the projection arrangement according to the invention,

[0077] FIG. 2 a plan view of the composite pane of FIG. 1,

[0078] FIG. 3-7 enlarged cross-sectional views of various embodiments of the projection arrangement according to the invention,

[0079] FIG. 8 a diagram showing the measured reflectivity R as a function of the wavelength WL in two different composite panes, and

[0080] FIG. 9 a flow chart illustrating the method according to the invention.

[0081] FIG. 1 depicts a cross-sectional view of an exemplary embodiment of the projection arrangement 100 according to the invention in a vehicle in a highly simplified, schematic representation. A plan view of the composite pane 1 of the projection arrangement 100 is depicted in FIG. 2. The cross-sectional view of FIG. 1 corresponds to the section line A-A of the composite pane 1, as indicated in FIG. 2.

[0082] The composite pane 1 is implemented in the form of a composite pane (cf. FIG. 3 through 4) and comprises an outer pane 2 and an inner pane 3 with a thermoplastic intermediate layer 4, which is arranged between the panes. The composite pane 1 is, for example, installed in a vehicle and separates a vehicle interior 12 from external surroundings 13. The composite pane 1 is, for example, the windshield of a motor vehicle.

[0083] The outer pane 2 and the inner pane 3 are made in each case of glass, preferably thermally toughened soda lime glass and are transparent to visible light. The thermoplastic intermediate layer 4 consists of a thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and/or polyethylene terephthalate (PET). The outer side I of the outer pane 2 faces away from the thermoplastic intermediate layer 4 and is, at the same time, the outer surface of the composite pane 1. The inner side II of the outer pane 2 and the outer side III of the inner pane 3 face the intermediate layer 4 in each case. The inner side IV of the inner pane 3 faces away from the thermoplastic intermediate layer 4 and is, at the same time, the inner side of the composite pane 1. It goes without saying that the composite pane 1 can have any suitable geometric shape and/or curvature. As a composite pane 1, it typically has convex curvature.

[0084] In an edge region 11 of the composite pane 1, there is a frame-like circumferential first masking strip 5 on the inner side II of the outer pane 2. The first masking strip 5 is opaque and prevents the view of structures arranged to the inside of the composite pane 1, for example, an adhesive bead for gluing the composite pane 1 into a vehicle body. The first masking strip 5 is preferably black. The first masking strip 5 is made of an electrically nonconductive material conventionally used for masking strips, for example, a black colored screen printing ink that is baked.

[0085] Furthermore, the composite pane 1 has, in the edge region 11 on the inner side IV of the inner pane 3, a second masking strip 6. The second masking strip 6 is implemented circumferentially in a frame-like manner. Like the first masking strip 5, the second masking strip 6 is made of an electrically nonconductive material conventionally used for masking strips, for example, a black colored screen printing ink that is baked.

[0086] On the first masking strip 5, there is a reflection layer 9 that is vapor deposited by means of a PVD method. When viewed through the composite pane 1, the reflection layer 9 does not coincide with the second masking strip 6. The reflection layer 9 is, for example, a metal coating that contains at least one thin-layer stack with at least one silver layer and one dielectric layer. Alternatively, the reflection layer 9 can also be implemented as a reflecting film and be arranged on the first masking strip 5. The reflecting film can include a metal coating or, however, be made of dielectric polymer layers in a layer sequence. Combinations of these variants are also possible.

[0087] When viewed through the composite pane 1, the reflection layer 9 is arranged in overlap with the first masking strip 5, with the first masking strip 5 completely overlapping the reflection layer 9, i.e., the reflection layer 9 has no section that is not in overlap with the first masking strip 5. Here, the reflection layer 9 is, for example, arranged only in the lower (engine-side) section 11 of the edge region 11 of the composite pane 1. However, it would also be possible to arrange the reflection layer 9 in the upper (roof-side) section 11 or in a lateral section of the edge region 11. Furthermore, a plurality of reflection layers 9 can be provided, arranged, for example, in the lower (engine-side) section 11 and in the upper (roof-side) section 11 of the edge region 11. For example, the reflection layers 9 could be arranged such that a (partially) circumferential image is generated.

[0088] The first masking strip 5 is widened in the lower (engine-side) section 11 of the edge region 11, i.e., the first masking strip 5 has in the lower (engine-side) section 11 of the edge region 11 a greater width than in the upper (roof-side) section 11 of the edge region 11 (as also in the lateral sections of the edge region 11, not visible in FIG. 1) of the composite pane 1. Width means the dimension of the first masking strip 5 perpendicular to its extension. Here, the reflection layer 9 is arranged, for example, above the second masking strip 6 (in other words, not in overlap).

[0089] The projection arrangement 100 further has an image display device 8 as an image generator arranged in the dashboard 7. The image display device 8 is used to generate p-polarized light 10 (image information) that is directed at the reflection layer 9 and is reflected by the reflection layer 9 as reflected light 10 into the vehicle interior 12, where it can be seen by a viewer, e.g., driver. The reflection layer 9 is suitably designed to reflect the p-polarized light 10 of the image display device 8, i.e., an image from the image display device 8. The p-polarized light 10 of the image display device 8 preferably strikes the composite pane 1 at an angle of incidence of 50 to 80, in particular of 60 to 70 1, typically approx. 65, as is customary with HUD projection arrangements. It would also, for example, be possible to arrange the image display device 8 in the A pillar of a motor vehicle or on the roof (on the vehicle-interior side, in each case), if the reflection layer 9 is suitably positioned for this. When multiple reflection layers 9 are provided, a separate image display device 8 can be associated with each reflection layer 9, i.e., multiple image display devices 8 can be arranged. The image display device 8 is, for example, a display, such as an LCD display, OLED display, EL display, or LED display. It would also be possible, for example, for the composite pane 1 to be a roof panel, side pane, or rear pane.

[0090] The plan view of FIG. 2 shows the reflection layer 9 extending along the lower section 11 of the edge region 11 of the composite pane 1.

[0091] Reference is now made to FIG. 3 through 7, wherein enlarged cross-sectional views of various embodiments of the composite pane 1 are depicted. The cross-sectional views of FIG. 3 through 7 correspond to the section line A-A in the lower section 11 of the edge region 11 of the composite panel, as indicated in FIG. 2.

[0092] In the variants of the composite pane 1 depicted in FIG. 3, the first (opaque) masking strip 5 is situated on the inner side II of the outer pane 2. The reflection layer 9 is applied directly on the first masking strip 5. The p-polarized light 10 from the image display device 8 is reflected by the reflection layer 9 as reflected light 10 into the vehicle interior 12. The p-polarization of the light 10, 10 is schematically illustrated. Due to the angle of incidence of the p-polarized light 10 on the composite pane 1 close to Brewster's angle, the p-polarized light 10 is hardly impeded in transmittance through the inner pane 3. This variant has the advantage that a relatively large share of the incident p-polarized light 10 is reflected; and, then, due to the fact that the angle of incidence is equal to the angle of reflection (depicted in FIGS. 3 and 4 by ), is transmitted, largely unimpeded, through the inner pane 3 into the vehicle interior 12. In addition, the image is readily recognizable against the background of the opaque (first) masking layer 5 with high contrast.

[0093] The variant of the composite pane 1 depicted in FIG. 4 differs from the variant of FIG. 3 only in that the reflection layer 9 is implemented as a reflecting film that reflects p-polarized light 10 into the vehicle interior 12. This variant represents a viable alternative to the reflection layer 9 shown in FIGS. 1 and 3, which is, for example, vapor deposited onto the masking strip 5 using the PVD technique.

[0094] As a further difference from the variant of FIG. 3, the reflection layer 9 in FIG. 4 is laminated between two thermoplastic intermediate layers 4, 4 (e.g., PVB films) in the composite pane 1. In order to compensate for height differences (thickness jump) caused by the reflection layer 9 relative to the rest of the composite pane 1, it is advantageous for the thermoplastic intermediate layers 4, 4 to have a correspondingly smaller thickness than outside the region, where the reflection layer 9 is not provided. Thus, a uniform distance (i.e., constant total thickness) between the outer pane 2 and the inner pane 3 can be achieved such that any glass breakage during lamination is reliably and safely avoided. When, for example, PVB films are used, they have a smaller thickness in the region of the reflection layer 9 than where no reflection layer 9 is provided. In addition, the image is easily recognizable against the background of the opaque (first) masking layer 5 with high contrast. In the interior of the composite pane 1, the reflection layer 9 is well protected against external influences.

[0095] The variant of the composite pane 1 depicted in FIG. 5 differs from the variant of FIG. 4 only in that the first (opaque) masking strip 5 is implemented as a thermoplastic intermediate layer impermeable to light that is arranged on the inner side II of the outer pane 2. The first masking strip 5 is formed, for example, based on a colored PVB, EVA, or PET film. In this case, the reflection layer 9 is laminated between the thermoplastic intermediate layer 4 and the first masking strip 5.

[0096] The variant of the composite pane 1 depicted in FIG. 6 differs from the variant of FIG. 4 only in that no (opaque) masking strip 5 is arranged on the outer or inner side I, II of the outer pane 2 and the reflection layer 9 itself is opaque. The reflection layer 9 is, for example, a reflecting film impermeable to light that is arranged within innerhalb the thermoplastic intermediate layer 4, 4. Due to the opacity of the reflection layer 9, the reflectivity for p-polarized light 10 is above 90%. The reflected, projected image is thus well recognizable for the viewer.

[0097] The variant of the composite pane 1 depicted in FIG. 7 differs from the variant of FIG. 3 only in that a high-refractive-index coating 14 is arranged on the inner side IV of the inner pane 3. The high-refractive-index coating 14 is applied, for example, by means of the sol-gel method and consists of a titanium oxide coating. Due to the higher refractive index (for example, 1.7) of the high-refractive-index coating 14 compared to the inner pane 3, the Brewster angle, normally at approx. 56.5 (for soda lime glass) can be enlarged, which simplifies the application and reduces the effect of disruptive double images due to reflection at the inner side IV of the inner pane 3.

[0098] In all exemplary embodiments, the reflection layer 9 is arranged on the vehicle-interior side of the first masking strip 5, i.e., when viewed from the inner side of the composite pane 1, the reflection layer 9 is arranged in front of the first masking strip 5.

[0099] FIG. 8 shows, using a diagram, the measured reflectivity R (in % of the incident p-polarized light 10) as a function of the wavelength (nm) with different angles of incidence of the p-polarized light 10 on the composite pane 1. The measurements were made at an angle of 50 (PL1), 55 (PL2), and 65 (PL3) relative to the normal. The curves relate to a composite pane 1 with a reflection layer 9 that is arranged on the masking strip 5. In this case, the masking strip 5 is arranged on the inner side II of the outer pane 2.

[0100] It can be seen that the reflectivity at all angles is from 90% to 100% for wavelengths >395 nm.

[0101] FIG. 9 illustrates the method according to the invention by means of a flow chart.

[0102] A: A thermoplastic intermediate layer 4 and a reflection layer 9 are arranged between a transparent outer pane 2 and a transparent inner pane 3 to form a layer stack. The reflection layer 9 is itself opaque or is arranged spatially farther from the outer side I of the outer pane 2 than an opaque background, for example, a masking strip 5 that is arranged on the outer side I or inner side II of the outer pane 2 or between the outer pane 2 and the inner pane 3.

[0103] B: The layer stack is laminated to form a composite pane 1.

[0104] C: An image display device 8 is arranged on the composite pane 1, wherein the emitting element of the image display device 8 is associated with the reflection layer 9 and the reflection layer 9 is irradiated through the inner pane 3 with a p-polarized light 10, with the reflection layer 9 reflecting the p-polarized light 10.

[0105] It follows from the above statements that the invention makes available an improved projection arrangement that enables a good image display with high contrast. Unwanted secondary images can be avoided. The projection arrangement according to the invention can be produced simply and economically using known production methods. [0106] 1 composite pane [0107] 2 outer pane [0108] 3 inner pane [0109] 4, 4, 4 thermoplastic intermediate layer [0110] 5 first masking strip [0111] 6 second masking strip [0112] 7 dashboard [0113] 8 image display device [0114] 9 reflection layer [0115] 10,10 p-polarized Licht [0116] 11, 11, 11 edge region [0117] 12 vehicle interior [0118] 13 external surroundings [0119] 14 high-refractive-index coating [0120] 100 projection arrangement [0121] I outer side of the outer pane 2 [0122] II inner side of the outer pane 2 [0123] III outer side of the inner pane 3 [0124] IV inner side of the inner pane 3 [0125] A-A section line