SEGMENTED MULTILAYER FILM WITH ELECTRICALLY CONTROLLABLE OPTICAL PROPERTIES

Abstract

A multilayer film having electrically controllable optical properties. The multilayer film has a first carrier film, a first planar electrode, an active layer having one or more layers in sequence, a second planar electrode, and a second carrier film, arranged one above the other in a planar manner. The first planar electrode and the active layer and optionally the second planar electrode are divided by at least one insulation line into at least two segments that are electrically insulated from one another. The insulation line is introduced with a laser through one of the carrier films and into the first planar electrode and the active layer and optionally the second planar electrode.

Claims

1.-15. (canceled)

16. A multilayer film having electrically controllable optical properties, comprising in the order specified and arranged one above the other in a planar manner: a) a first carrier film, b) a first planar electrode, c) an active layer comprising one or more layers in sequence, the active layer having electrically controllable optical properties, d) a second planar electrode, and e) a second carrier film, wherein the first planar electrode and the active layer are divided by at least one insulation line into at least two segments that are electrically insulated from one another, wherein the at least one insulation line is laser machined through one of the first carrier film or second carrier film and into the first planar electrode and the active layer.

17. The multilayer film according to claim 16, wherein the multilayer film is an electrochromic multilayer film having electrochromic active layers, the electrochromic active layers comprising in the order specified and arranged one above the other in a planar manner: c1) an ion storage layer, c2) an electrolyte layer, and c3) an electrochromic layer.

18. The multilayer film according to claim 16, wherein the multilayer film is a polymer-dispersed liquid crystal multilayer film, wherein the active layer is a polymer-dispersed liquid crystal layer that contains liquid crystals embedded in a polymer matrix, and wherein the second planar electrode is divided by the at least one insulation line into at least two segments that are electrically insulated from one another.

19. The multilayer film according to claim 16, wherein the at least one insulation line extends through the first planar electrode and the active layer, wherein material of the first planar electrode is completely removed or chemically modified in a first region of the at least one insulation line such that a resulting at least two first planar electrode segments are electrically insulated from one another, and wherein material of the active layer is completely removed or chemically modified in a second region of the at least one insulation line such that a resulting at least two active layer segments are electrically insulated from one another.

20. The multilayer film according to claim 16, wherein a line width of the at least one insulation line is less than or equal to 500 ?m.

21. The multilayer film according to claim 20, wherein the line width of the at least one insulation line is between 10 ?m and 150 ?m.

22. The multilayer film according to claim 21, wherein the line width of the at least one insulation line is between 20 ?m and 100 ?m.

23. The multilayer film according to claim 16, wherein the first carrier film and the second carrier film comprise polyethylene terephthalate and have a thickness of 0.1 mm to 0.5 mm.

24. The multilayer film according to claim 16, wherein the first planar electrode and the second planar electrode comprise silver or indium tin oxide and have a thickness of 20 nm to 1 ?m.

25. A laminated pane comprising a first pane, a second pane, and a multilayer film according to claim 16, wherein the multilayer film is arranged between the first pane and the second pane and is connected to the first pane via a first thermoplastic bonding film and the second pane via a second thermoplastic bonding film.

26. The laminated pane according to claim 25, wherein the first pane and the second pane are glass panes.

27. A method for fabricating a multilayer film having electrically switchable optical properties, the method comprising: (A) providing a multilayer film having electrically controllable optical properties, the multilayer film comprising in the order specified and arranged one above the other in a planar manner: a) a first carrier film, b) a first planar electrode, c) an active layer comprising one or more layers in sequence, the active layer having electrically controllable optical properties, d) a second planar electrode, and e) a second carrier film, (B) directing laser radiation through the first carrier film or second carrier film to the first planar electrode, the active layer and the second planar electrode, and (C) moving the laser radiation along at least one line to introduce at least one insulation line into the first planar electrode and the active layer such that the first planar electrode is divided into at least two first planar electrode segments that are electrically insulated from one another and the active layer is divided into at least two active layer segments that are electrically insulated from one another.

28. The method according to claim 27, wherein the laser radiation is moved exactly once along the at least one line, and wherein a first insulation line is simultaneously introduced into the first planar electrode and the active layer.

29. The method according to claim 28, wherein the first insulation line is further simultaneously introduced into the second planar electrode.

30. The method according to claim 27, wherein a wavelength of the laser radiation is from 200 nm to 1200 nm.

31. The method according to claim 30, wherein the wavelength of the radiation is from 300 nm to 400 nm.

32. The method according to claim 27, wherein the laser radiation is moved at a speed of 100 mm/s to 10000 mm/s.

33. The method according to claim 27, wherein the laser is operated in pulsed mode.

34. The method according to claim 33, wherein a pulse length is less than or equal to 50 ns.

35. A structure comprising the multilayer film according to claim 16, the structure being selected from the group consisting of: i) a glazing, ii) a laminated pane, iii) an access or a window region in a building, and iv) a rear pane, side pane, or roof panel on a train, ship, aircraft or motor vehicle.

Description

[0079] The invention is explained in more detail with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and is not true to scale. The drawing does not limit the invention in any way. Shown are:

[0080] FIG. 1 shows a plan view of an embodiment of a laminated pane according to the invention, comprising a multilayer film according to the invention;

[0081] FIG. 2 shows a cross-section along X-X through the laminated pane according to FIG. 1;

[0082] FIG. 3 shows a plan view of the multilayer film before the production of the laminated pane according to FIG. 1;

[0083] FIG. 4 shows a cross-section along Y-Y through the multilayer film of FIG. 3;

[0084] FIG. 5 shows a cross-section along Y-Y of a further embodiment of the multilayer film according to the invention;

[0085] FIG. 6 shows a cross-section along Y-Y of a further embodiment of the multilayer film according to the invention;

[0086] FIG. 7 shows a cross-section through the multilayer film according to FIG. 3 during the method according to the invention;

[0087] FIG. 8 shows a plan view of a further embodiment of the multilayer film according to the invention; and

[0088] FIG. 9 shows a plan view of a further embodiment of the multilayer film according to the invention,

[0089] FIGS. 1 and 2 each show a detail of a laminated pane according to the invention having electrically controllable optical properties. The laminated pane is provided, for example, as a roof panel of a passenger vehicle, the light transmission of which can be electrically controlled in regions. The laminated pane comprises a first pane 12 (outer pane) and a second pane 13 (inner pane), which are connected to one another by a thermoplastic intermediate layer. The first pane 12 and the second pane 13 consist of soda lime glass, which can optionally be tinted. For example, the first pane 12 has a thickness of 2.1 mm, and the second pane 13 has a thickness of 1.6 mm.

[0090] The intermediate layer comprises a total of three thermoplastic layers 14a, 14b, 14c which are each formed by a thermoplastic film having a thickness of 0.38 mm and made of PVB. The first thermoplastic layer 14a is connected to the first pane 12, and the second thermoplastic layer 14b is connected to the second pane 13. The third thermoplastic layer 14c located in between has a cutout in which a multilayer film 1 having electrically controllable optical properties is inserted essentially in a precise fit, i.e., approximately flush on all sides. The third thermoplastic layer 14c thus forms quasi some kind of mount or frame for the approximately 0.3 mm thick multilayer film 1, which is thickened to approximately 0.4 mm in the edge region by the busbars used for electrical contacting. The multilayer film 1 is thus completely encapsulated in the thermoplastic material and protected thereby. The multilayer film 1 is, for example, an electrochromic multilayer film which can be switched from a transparent, uncolored state into a colored state with reduced light transmission.

[0091] The laminated pane has, for example, four independent switching regions S1, S2, S3, S4 in which the switching state of the multilayer film 1 can be set independently of one another. The switching regions S1, S2, S3, S4 are arranged one behind the other in the direction from the front edge to the rear edge of the roof panel, wherein the terms front edge and rear edge relate to the direction of travel of the vehicle. With the switching regions S1, S2, S3, S4, the driver of the vehicle can choose (for example as a function of the position of the sun) to darken only one region of the laminated pane instead of the entire laminated pane, while the other regions remain transparent.

[0092] The laminated pane has a circumferential edge region which is provided with an opaque cover printing 15. The said cover printing 15 is typically formed from a black enamel. It is imprinted as printing ink with a black pigment and glass frits in a screen-printing method and is burned into the pane surface. The cover printing 15 is applied, for example, on the interior-side surface of the first pane 12 and also on the interior-side surface of the second pane 13. The side edges of the multilayer film 1 are covered by this cover printing 15.

[0093] FIGS. 3 and 4 each show a detail of the multilayer film 1 before it has been laminated into the laminated pane according to FIG. 1. The multilayer film 1 is delimited by a first carrier film 5 and a second carrier film 6. The carrier films 5, 6 are made of PET and have a thickness of, for example, 0.125 mm. The carrier films 5, 6 are provided with a coating made of ITO with a thickness of about 100 nm and form a first planar electrode 3 and a second planar electrode 4. An active layer sequence 2 is arranged between the planar electrodes 3, 4. The layer sequence 2 is an electrochromic layer sequence and consists of an ion storage layer 2a, an electrolyte layer 2b and an electrochromic layer 2c. By means of a DC voltage applied to the planar electrodes 3, 4, ions can be excited to migrate from the ion storage layer 2a through the electrolyte layer 2b and into the electrochromic layer 2c, and vice versa. The amount of ions in the electrochromic layer 2c determines its optical properties, in particular the degree of light transmission and the color.

[0094] The multilayer film 1 has three insulation lines 7 which extend parallel to one another from one side edge to the opposite side edge. The insulation lines 7 separate the first planar electrodes 3 and the active layer sequence 2 into segments electrically insulated from one another. These segments form the four independent switching regions S1, S2, S3, S4 of the multilayer film 1 or later of the laminated pane. The second planar electrode 4 is not completely separated into segments by the insulation lines 7the insulation lines 7 extend only over a part of the layer thickness of the second planar electrode 4, for example approximately 10%. The segments of the first planar electrode 3 are electrically contacted independently of one another and connected to a voltage source, so that the optical properties of the switching regions S1, S2, S3, S4 can be controlled independently of one another. The non-segmented second planar electrode 4 provides a reference potential for all segments of the first planar electrode 3.

[0095] FIG. 5 shows a cross-section through a further embodiment of the multilayer film 1 according to the invention. The multilayer film 1 is an electrochromic multilayer film which is basically designed as in FIG. 4. In contrast, the insulation lines 7 extend not only through the first planar electrode 3 and the active layer sequence 2, but also through the second planar electrode 4. The second planar electrode 4 is thus also divided by the insulation lines 7 into segments electrically insulated from one another, which are electrically contacted independently of one another.

[0096] FIG. 6 shows a cross-section through a further embodiment of the multilayer film 1 according to the invention. It is a PDLC multilayer film. It also comprises two carrier layers 5, 6 and two planar electrodes 3, 4, which are designed in the same way as in the case of the electrochromic multilayer film of FIG. 4. An active layer 2 is arranged between the planar electrodes 3, 4. The active layer 2 is a PDLC layer and contains liquid crystals in a polymer matrix which can be aligned by an alternating voltage applied to the planar electrodes 3, 4. The active layer 2 is then transparent. Without voltage, the liquid crystals are present in an unaligned manner, leading to a state of strong light scattering. Both planar electrodes 3, 4 and the active layer 2 are divided into four segments by three insulation lines 7, which segments form independent switching regions S1, S2, S3, S4.

[0097] FIG. 7 shows a cross-section through the electrochromic multilayer film 1 of FIG. 3 during the method according to the invention. For the sake of simplicity, the electrochromic layer sequence 2 is shown as a single layer. The multilayer film 1 is cut, for example, from a purchased film. By means of a f-theta lens as focusing element 10, the radiation 9 of a laser 8 is directed through the first carrier film 5 at position x.sub.0 and to the planar electrodes 3, 4 and the layer sequence 2 located in between, for example focused on the first planar electrode 3 (FIG. 7a). The radiation 9 can be moved along direction x over the multilayer film 1 by means of a movable mirror 11. The movement of the radiation 9 leads to a laser-induced degeneration of the first planar electrode 3 and all layers 2a, 2b, 2c of the layer sequence 2. At a later point in time (FIG. 7b), the radiation 9 has been moved from position x.sub.0 to position x.sub.1, resulting in an insulation line 7 within the first planar electrode 3 and all layers 2a, 2b, 2c of the layer sequence 2 between positions x.sub.0 and x.sub.1. The insulation line 7 is an electrically non-conductive linear region which extends over the entire thickness of the first planar electrode 3 and the electrochromic layer sequence 2 and the course of which depends on movement direction x. The second planar electrode 4 is only slightly influenced, in particular not completely severed, by the laser. The carrier film 5 is not damaged when the insulation line 7 is introduced.

[0098] The figure is to be understood merely as an example to illustrate the principle according to the invention. In order to produce the insulation lines 7 according to FIG. 3, it is expedient to move the radiation 9 from one side edge of the multilayer film 1 (position x.sub.0) to the opposite side edge (position x.sub.1).

[0099] Proper process control makes it possible also to cut through the second planar electrode 4 in addition to the first planar electrode 3 and the active layer sequence 2. This can be achieved by suitably adapting the parameters of the laser radiation and/or by repeatedly moving over the line to be cut.

[0100] FIG. 8 shows a further embodiment of the multilayer film 1 according to the invention, again, by way of example, an electrochromic multilayer film. The insulation line 7 describes a closed shape which for the sake of simplicity is shown as a square. The planar electrodes 3, 4 and the active layer sequence 2 are severed by the insulation line 7, whereby the enclosed region is electrically insulated from the surrounding region. The surrounding region is provided as a switching region S1 the optical properties of which can be electrically controlled. In principle, the enclosed region can also be provided as a switching region, which, however, would require electrical contacting in the viewing area of the laminated pane into which the multilayer film 1 is to be laminated. This is disadvantageous because it is visually noticeable. The embodiment is therefore particularly suitable for electrically insulating the enclosed region and thereby exempting it from the control of the optical properties. The enclosed region therefore retains its optical properties, irrespective of the switching state of the surrounding region. The insulation line 7 can, for example, have the shape of a symbol or company logo, which is thus made visible in an aesthetically appealing manner.

[0101] FIG. 9 shows a further embodiment of the multilayer film 1 according to the invention, again, by way of example, an electrochromic multilayer film. The two ends of the insulation line 7 are arranged on a side edge of the multilayer film 1, with a relatively small distance from one another. The insulation line 7 thus runs from the side edge toward the center of the multilayer film 1, where it describes a geometric figure and runs back to the same side edge. The two partial regions, which are insulated from one another, of the planar electrodes 3, 4 and the active layer sequence 2 can be designed as independent switching regions S1, S2. The switching region S2 enclosed by the insulation line 7 also extends to the side edge of the multilayer film 1, where it can be electrically contacted in a visually inconspicuous manner. The said geometric figure can be, for example, a symbol with which information is displayed to the user when the switching states of the switching regions S1, S2 are different.

EXAMPLES

[0102] Electrochromic multilayer films 1 as provided in FIG. 4 were provided. With the method according to the invention, insulation lines 7 were introduced into the first planar electrode 3 and the active layer sequence 2 to produce a plurality of independent switching regions. The multilayer films 1 were then assessed by visual inspection. In addition, the switching behavior was assessed, in particular in terms of whether switching states of switching regions cause an undesired change in the optical properties in adjacent, actually voltage-free switching regions (leakage).

[0103] The tests were carried out with laser radiation of various wavelengths and various pulse lengths. A Yb:YAG laser operated in pulsed mode was used in each case as laser 8, which was operated with its fundamental radiation (1064 nm), frequency-doubled (515 nm, second harmonic) and frequency-tripled (343 nm; third harmonic).

[0104] The laser radiation 9 was focused onto the multilayer film 1 by means of a f-theta lens having a focal length of 250 mm and moved over it. The output power of the laser radiation 9 was 10 W in each case, the movement speed was 1 m/s.

[0105] The observations at different wavelengths and pulse lengths are summarized in Table 1, wherein: [0106] [1] means optimal result: [0107] Segments are electrically insulated (no leakage), no burns or blistering in the multilayer film 1 [0108] [2] means less good result: [0109] Segments are electrically insulated (no leakage), no burns, but blistering in the multilayer film 1 [0110] [3] means unacceptable result: [0111] segments are not electrically insulated (leakage) and/or [0112] burns and blistering in the multilayer film 1

TABLE-US-00001 TABLE 1 Wavelength 343 nm 515 nm 1030 nm Pulse length 200 fs [3] [2] [3] 800 fs [3] [2] [2] 10 ps [3] [2] [3] 1.5 ns [1] 20 ns [1] [3] [3]

[0113] The best results were achieved with UV radiation (343 nm) and pulse lengths in the nanosecond range. Acceptable results with pulse lengths in the femtosecond and picosecond range were achieved with green laser radiation (515 nm). It can be assumed that the slight impairments of the multilayer film 1 (blistering) can be avoided by optimizing the laser parameters. With IR radiation (1030 nm), acceptable results were achieved only in a single example (pulse length 800 fs).

[0114] The results suggest that when using UV radiation (for example 200 nm to 400 nm), pulse lengths in the nanosecond range are preferred (for example 1 ns to 25 ns), while when using radiation in the visible and IR range (for example 500 nm to 600 nm and 950 nm to 1050 nm), pulse lengths in the femtosecond and picosecond range are preferred (for example 100 fs to 50 ps).

LIST OF REFERENCE SIGNS

[0115] (1) Multilayer film having electrically controllable optical properties [0116] (2) Active layer of the multilayer film 1 [0117] (2) Active layer sequence of the multilayer film 1 [0118] (2a) Ion storage layer of an electrochromic layer sequence 2 [0119] (2b) Electrolyte layer of an electrochromic layer sequence 2 [0120] (2c) Electrochromic layer of an electrochromic layer sequence 2 [0121] (3) First planar electrode of the multilayer film 1 [0122] (4) Second planar electrode of the multilayer film 1 [0123] (5) First carrier film of the multilayer film 1 [0124] (6) Second carrier film of the multilayer film 1 [0125] (7) Insulation line [0126] (8) Laser [0127] (9) Radiation of the laser 8 [0128] (10) Focusing element [0129] (11) Tiltable mirror [0130] (12) First pane [0131] (13) Second pane [0132] (14a) First thermoplastic bonding film [0133] (14b) Second thermoplastic bonding film [0134] (14c) Third thermoplastic bonding film [0135] (15) Cover printing

[0136] (V) Laminated pane [0137] (S1, S2, S3, S4) Independent switching regions of the multilayer film 1 or laminated pane V x Direction of movement of the radiation 9 [0138] x.sub.0, x.sub.1 Positions of the radiation 9 during the method according to the invention [0139] X-X Cutting line [0140] Y-Y Cutting line