Vehicle window pane having a composite comprising a liquid crystal arrangement

Abstract

A vehicle window pane having a plate-like window pane body which has an outer side which faces the surroundings of the vehicle and an inner side which faces away from the outer side and to which a composite is connected, the composite having a layer structure which may have multiple layers disposed one on top of the other, one of the layers having a liquid crystal arrangement having two films and a liquid crystal cell disposed between the two films, and another one of the layers being a polarizer layer. At least one layer of the layer structure can be a compensation layer whose area is smaller than the area of the liquid crystal arrangement, the liquid crystal cell thus having an edge portion which is thicker than a central portion covered by the compensation layer.

Claims

1. A vehicle window pane comprising: a plate-like window pane body which has an outer side which faces the surroundings of the vehicle and an inner side which faces away tram the outer side and to which a composite is connected, the composite having a layer structure which comprises multiple layers disposed one on top of the other, one of the layers comprising a liquid crystal arrangement which comprises two films and a liquid crystal cell disposed between the two films, and another one of the layers being a polarizer layer, wherein at least one layer of the layer structure is a displacement layer whose area is smaller than the area of the liquid crystal arrangement, the liquid crystal cell thus having an edge portion which is thicker than a central portion covered by the displacement layer due to the pressure applied to the central portion by the displacement layer, and the edge portion is not covered by the displacement layer.

2. The vehicle window pane of claim 1, wherein the displacement layer is formed by the polarizer layer.

3. The vehicle window pane of claim 1, wherein the displacement layer is formed by an additional film.

4. The vehicle window pane of claim 3, wherein the additional layer is adjacent to the liquid crystal arrangement.

5. The vehicle window pane of claim 3, wherein the additional layer is adjacent to the polarizer layer.

6. The vehicle window pane of claim 3, wherein the additional layer is disposed between the liquid crystal arrangement and the polarizer layer.

7. The vehicle window pane of claim 3, wherein the additional layer has a thickness between 10 μm and 500 μm.

8. The vehicle window pane of claim 3, wherein a window pane inner body is glued to the layer structure.

9. The vehicle window pane of claim 8, wherein the additional layer is adjacent to the window pane inner body.

10. The vehicle window pane of claim 1, wherein the layer structure comprises an adhesive layer for being connected to the window pane body.

11. The vehicle window pane of claim 1, wherein the layer structure comprises an adhesive layer between the liquid crystal arrangement and the polarizer layer.

12. The vehicle window pane of claim 10, wherein the adhesive layer is made of at least one of a layer selected from the group consisting of an acrylate layer, a layer of thermo-plastic polyurethane, an epoxy layer, a silicone layer, a polyethylene layer and a layer of a cross-linking material, such as ethylene-vinyl acetate (EVA) or polyvinyl butyral (PVB).

13. The vehicle window pane of claim 3, wherein the additional layer is made of at least one of a layer selected from the group consisting of an acrylate layer, a layer of thermoplastic polyurethane, an epoxy layer, a silicone layer, a polyethylene layer, a layer of a cross-linking material such as ethylene-vinyl acetate (EVA) or polyvinyl butyral (PVB), and a transparent plastic film, which consists of one of a polyethylene terephthalate (PET), polycarbonate (PC) or a cyclic olefin copolymer (COC).

14. The vehicle window pane of claim 1, wherein the edge portion of the liquid crystal cell has a width between 5 mm and 40 mm.

15. The vehicle window pane of claim 1, wherein the layer structure has a circumferential edge which is surrounded by an edge sealing, which consists a film structure.

Description

(1) Embodiments of a vehicle window pane according to the invention are illustrated in a schematically simplified manner in the drawing and will be explained in more detail in the following description.

BRIEF DESCRIPTIONS OF THE DRAWINGS

(2) FIG. 1 is a plan view of a vehicle roof having a vehicle window pane according to the invention;

(3) FIG. 2 is a section through the vehicle window pane showing the layer structure of the vehicle window pane;

(4) FIG. 3 is a section through a second embodiment of a vehicle window pane;

(5) FIG. 4 is a section through a third embodiment of a vehicle window pane;

(6) FIG. 5 is a section through a fourth embodiment of a vehicle window pane;

(7) FIG. 6 is a section through a fifth embodiment of a vehicle window pane;

(8) FIG. 7 is a section through a sixth embodiment of a vehicle window pane;

(9) FIG. 8 is a section through a seventh embodiment of a vehicle window pane;

(10) FIG. 9 is a section through an eighth embodiment of a vehicle window pane;

(11) FIG. 10 is a section through a ninth embodiment of a vehicle window pane;

(12) FIG. 11 is a section through a tenth embodiment of a vehicle window pane;

(13) FIG. 12 is a section through an eleventh embodiment of a vehicle window pane;

(14) FIG. 13 is a section through a twelfth embodiment of a vehicle window pane; and

(15) FIG. 14 is a section through a thirteenth embodiment of a vehicle window pane.

DETAILED DESCRIPTION

(16) FIG. 1 shows a vehicle roof 10 of a motor vehicle (not shown in detail). Vehicle roof 10 is a panoramic sunroof, which is provided with a displaceable lid element 12 and a fixed roof element 14, which is immobile relative to the vehicle body. Lid element 12 and fixed roof element 14 are each realized as a glass element and thus each form a vehicle window pane. Moreover, lid element 12 and fixed roof element 14 each have the same layer structure, which is provided with a shading arrangement and illustrated in detail in FIG. 2.

(17) Roof elements 12 and 14, which each form a vehicle window pane, each comprise a window pane body 16 made of a glass plate which is curved in a longitudinal direction and in a transverse direction of the roof and which foil is the outer skin of the vehicle window pane in question, the outer skin being exposed to the surroundings of the vehicle. At the inner side, each vehicle window pane comprises a window pane inner body 18, which is also made of a curved glass plate. Window pane body 16 and window pane inner body 18 each have a thickness of about 2.0 mm.

(18) A composite 20, which is connected to window pane body 16 via a TPU adhesive film 22 and to window pane inner body 18 via a TPU adhesive film 24, is disposed between window pane body 16 and window pane inner body 18. Moreover, composite 20 comprises a shading arrangement 26, which is formed by a liquid crystal arrangement 28 and a polarizer layer 30. Liquid crystal arrangement 28 comprises two transparent films 32 and 34 of PET or polycarbonate, between which a single liquid crystal cell 36 is disposed. The two transparent films 32 and 34 each have a thickness of about 100 μm. In order to be able to switch liquid crystal cell 36 between a transmission state and a blocking state, conductive layers are integrated in liquid crystal arrangement 28 on the inner sides of films 32 and 34, the conductive layers being connected to an onboard electrical system of the vehicle in question via corresponding contacts (not shown). Respective alignment layers are preferably disposed on the conductive layers, the alignment layers delimiting liquid crystal cell 26. The alignment layers serve to pre-align the crystals of liquid crystal cell 26 in the switched-off state and may each be made of a polyimide or a UV-curing acrylate.

(19) An adhesive layer 38 made of TPU is disposed between polarizer layer 30 and liquid crystal arrangement 28.

(20) An additional layer 40 is connected to liquid crystal arrangement 28 on the side facing away from window pane body 16, the side of additional layer 40 that faces away from window pane body 16 being adjacent to adhesive film 24 and forming a displacement layer. Additional layer 40 is an additional film, which is made of thermoplastic polyurethane (TPU) and has a thickness of about 100 μm. As can be seen further in FIG. 2, additional layer 40 has an area that is smaller than the areas of liquid crystal arrangement 28, polarizer layer 30, adhesive films 22 and 24 and adhesive layer 38. Thus, a circumferential empty space 42 is formed below a circumferential edge portion of liquid crystal arrangement 28 during joining of composite 20, circumferential empty space 42 having the effect that the pressure exerted on liquid crystal arrangement 28 by additional layer 40 causes liquid crystal cell 36 to be thicker in the edge portion disposed above empty space 42 than in a central portion covered by additional layer 40. This means that a liquid crystal reservoir 44 forms in the edge portions of liquid crystal cell 36 because the liquid crystal material accumulates there. Empty space 42 has a width of about 30 mm and is located outside of the transparent area of the vehicle window pane.

(21) Furthermore, the vehicle window pane is provided with an edge sealing 46 which protects liquid crystal arrangement 28 and composite 20 against environmental conditions.

(22) After a lamination process for producing the vehicle window pane, empty space 42 may be filled at least partially by the material of adhesive film 24 and, if present, additional layer 40 as a result of the pressures and temperatures acting during that process.

(23) FIG. 3 shows an alternative embodiment of a window pane arrangement 50, which substantially corresponds to the window pane arrangement of FIG. 2, but differs from it in that a decoupling layer 52 is connected to lower film 34 of liquid crystal arrangement 28 in the area of empty space 42, decoupling layer 52 having the task of preventing the polyurethane of adhesive film 24 from adhering to liquid crystal arrangement 28.

(24) Otherwise, window pane arrangement 50 corresponds to the window pane arrangement of FIG. 2.

(25) FIG. 4 shows a window pane arrangement 60, which again corresponds largely to the window pane arrangement of FIG. 2 but differs from it in that polarizer layer 30 has an area or dimensions corresponding to the dimensions of additional layer 40. Thus, polarizer layer 30 is also surrounded by an empty space 62, which means that polarizer layer 30 also acts as a displacement layer and that liquid crystal reservoir 44 forms in the edge portion of liquid crystal cell 36.

(26) FIG. 5 shows another embodiment of a window pane arrangement 70, which substantially corresponds to the window pane arrangement of FIG. 2 but differs from it in that additional layer 40, which forms a displacement layer, is disposed on top of liquid crystal arrangement 28. That is, additional layer 40 is disposed between polarizer layer 30 and liquid crystal arrangement 28. Otherwise, window pane arrangement 70 corresponds to the window pane arrangement of FIG. 2.

(27) FIG. 6 shows another embodiment of a window pane arrangement 80, which substantially corresponds to the window pane arrangement of FIG. 5 but differs from it in that no additional adhesive layer is disposed between additional layer 40 disposed on top of liquid crystal arrangement 28 and polarizer layer 30. Instead, additional layer 40, whose area is smaller than that of polarizer layer 30 and of liquid crystal arrangement 28, forms a coupling layer between these two functional layers.

(28) FIG. 7 shows another embodiment of a window pane arrangement 90, which largely corresponds to the window pane arrangement of FIG. 4 but differs from it in that it has no additional layer. Instead, polarizer layer 30 alone forms a displacement layer which causes the formation of liquid crystal reservoir 44.

(29) FIG. 8 shows a window pane arrangement 100 which largely corresponds to the window pane arrangement of FIG. 2 but differs from it in that additional layer 40 is adjacent to window pane inner body 18 instead of being directly adjacent to liquid crystal arrangement 28. Moreover, an adhesive layer 102 of thermoplastic polyurethane is disposed between additional layer 40 and liquid crystal arrangement 28. Similar to the embodiments described above, additional layer 40, which forms the displacement layer, is delimited by an empty space 42 which causes a liquid crystal reservoir 44 to form in the edge portion of liquid crystal cell 36 when composite 20 is joined. Otherwise, window pane arrangement 100 corresponds to the window pane arrangement of FIG. 2.

(30) FIG. 9 shows a window pane arrangement 110 which is a combination of the window pane arrangements illustrated in FIGS. 2 and 5 and which has an additional layer 40 both underneath and on top of liquid crystal arrangement 28, additional layer 40 forming a displacement layer and being delimited by an empty space 42 which facilitates the formation of a thickened liquid crystal cell 36 in its edge portions, i.e., the formation of a liquid crystal reservoir 44 in the edge portions of liquid crystal cell 36 due to the pressure applied to a central portion by additional layers 40.

(31) Otherwise, window pane arrangement 110 corresponds to the window pane arrangements of FIGS. 2 and 5.

(32) FIG. 10 shows another window pane arrangement 120, which largely corresponds to the embodiment of FIG. 7 but differs from it in that polarizer layer 30 is in direct contact with upper film 32 of liquid crystal arrangement 28. Again, polarizer layer 30 forms a displacement layer which, because its area is smaller than that of liquid crystal arrangement 28, is surrounded by an empty space 62 which causes a liquid crystal reservoir 44 to form in the edge portions of liquid crystal cell 36. Otherwise, window pane arrangement 120 corresponds to the window pane arrangement of FIG. 7.

(33) FIG. 11 shows a window pane arrangement 130 which largely corresponds to the embodiment of FIG. 8 but differs from it in that polarizer layer 30 has an area that is equal to the area of additional layer 40. A TPU adhesive film 132 is also disposed in the composite portions that are laterally adjacent to polarizer layer 30 and which are flush with empty space 42, which is adjacent to additional layer 40, in the direction of the normal. Moreover, liquid crystal arrangement 28 does not reach edge sealing 46. Instead, a circumferential strip 134 of TPU film is disposed between the lateral edges of liquid crystal arrangement 28 and edge sealing 46. Otherwise, window pane arrangement 130 corresponds to the window pane arrangement of FIG. 8, which is why reference is made to the description of the latter.

(34) FIG. 12 shows a window pane arrangement 140 which largely corresponds to the window pane arrangement of FIG. 11 but differs from it in that an adhesive film 24 is additionally disposed between adhesive layer 102 and window pane inner body 18, adhesive film 24 again being made of TPU. Otherwise, window pane arrangement 140 corresponds to the window pane arrangement of FIG. 11. That is, polarizer layer 30 has an area that is equal to the area of additional layer 40.

(35) FIG. 13 shows a window pane arrangement 150 which largely corresponds to the window pane arrangement of FIG. 11 but differs from it in that, like the embodiment of FIG. 9, it has a second additional layer 40, which, however, is disposed between adhesive film 22 (upper adhesive film in the drawing) and outer window pane body 16. Correspondingly, a lower or inner additional layer 40 is disposed between adhesive layer 102 and window pane inner body 18 and is directly adjacent to them. Upper/outer additional layer 40 is circumferentially delimited by an empty space 42 and has an area that is equal to the area of lower additional layer 40. Polarizer layer 30 has an area that is equal to the area of liquid crystal arrangement 28. Correspondingly, the circumferential edge of polarizer layer 30 is delimited by a TPU film 132. Otherwise, window pane arrangement 150 corresponds to the window pane arrangement of FIG. 11.

(36) FIG. 14 shows a window pane arrangement 160 which largely corresponds to the embodiment of FIG. 13 but differs from it in that composite 20 has additional adhesive films 24 and 162 adjacent to outer window pane body 16 and adjacent to window pane inner body 18, respectively, adhesive films 24 and 162 being made of TPU and the inner sides of adhesive films 24 and 162, which face liquid crystal arrangement 28, being directly adjacent to respective additional layers 40, which are displacement layers. Otherwise, the structure of window pane arrangement 160 corresponds to the structure of FIG. 13.

REFERENCE SIGNS

(37) 10 vehicle roof 12 lid 14 fixed roof element 16 window pane body 18 window pane inner body 20 composite 22 adhesive film 24 adhesive film 26 shading arrangement 28 liquid crystal arrangement 30 polarizer layer 32 film 34 film 36 liquid crystal cell 38 adhesive layer 40 additional layer 42 empty space 44 liquid crystal reservoir 46 edge sealing 50 window pane arrangement 52 decoupling layer 60 window pane arrangement 62 empty space 70 window pane arrangement 80 window pane arrangement 90 window pane arrangement 100 window pane arrangement 102 adhesive layer 110 window pane arrangement 120 window pane arrangement 130 window pane arrangement 132 TPU film 134 strip 140 window pane arrangement 150 window pane arrangement 160 window pane arrangement 162 adhesive film