CN115397785A - Composite glass pane having a selectively adjustable transmission in sections - Google Patents

Abstract

Composite glass pane with a segmentally adjustable selective transmission, comprising at least-a first substrate (1) and a second substrate (3) which are joined to one another by means of a thermoplastic interlayer (2), -a selectively polarizing layer (4 a) which is variable in such a way that it preferentially allows s-polarized or p-polarized light to pass through, and-a coating (4 b) which preferentially allows p-polarized light to pass through, wherein the selectively polarizing layer (4 a) and the coating (4 b) are superposed on one another in a planar fashion, and wherein the coating (4 b) has at least one silver layer.

Description

Composite glass pane having a selectively adjustable transmission in sections

The invention relates to a composite glass pane having a selectively adjustable transmission in sections.

It is known from vehicle construction to provide a colour band at the upper edge of the windscreen panel, for example a green-tinted PVB band on or in the windscreen panel, in order to prevent glare from the sun.

However, it has been shown that the harsh levels provided in this case are visually disturbing. Furthermore, glare protection is not required under all conditions of use. Depending on the position of the sun, glare protection may or may not be required. Especially when the sun is low, glare protection is important and it is therefore desirable to be switchable.

It is known that the transmission behavior of transparent substrates can be controlled by means of so-called PDLC (english: polymer dispersed liquid crystal, abbreviated PDLC). The active layer here contains liquid crystals embedded in a polymer matrix. If no voltage is applied, the liquid crystals are aligned in a disordered manner, which results in strong scattering of the light through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals are aligned in a common direction, and the light transmittance through the active layer increases. PDLC functions act less by reducing the overall transmission, but by increasing the scattering, to ensure glare protection. The use of PDLC functions in vehicle visors is disclosed for example in WO 2017/157626 A1. The combination of a PDLC element with a polarizing layer in the form of a plastic film is disclosed in WO2020/083561 A1.

However, simple PDLC is disadvantageous for various reasons. One reason is that PDLC is milky turbid in the voltage-free state. One disadvantage is the ability to switch only between two levels of opacity and transparency, and thus the ability to fine tune the transmission of light.

It is also known to use so-called electrochromic layers for switching the transmission properties of, for example, switchable building glazings. However, electrochromic solutions are more likely to be characterized by slow response behavior and high manufacturing costs.

It is an object of the present invention to provide a composite glass sheet that includes selected regions in which light transmittance can be controlled and in which light transmittance decreases according to the angle of incident light. At the same time, the composite glass pane should be able to be realized cost-effectively.

This object is achieved by a composite glass pane having a selectively adjustable transmission in sections. The composite glass sheet has a first substrate and a second substrate bonded to each other by a thermoplastic interlayer. In addition, the composite glass sheet has a selective polarizing layer and a coating, wherein the selective polarizing layer is variable such that it preferentially allows s-polarized or p-polarized light to pass through, and wherein the coating preferentially allows p-polarized light to pass through. This means that the coating allows more p-polarized light to pass than s-polarized light. The selective polarization layer and the coating are here placed on top of each other in the form of a surface. This means that they are arranged in the same area of the composite glass sheet.

Thus, the light transmittance in the area having the selective polarizing layer and the coating may be controlled by the interaction of the selective polarizing layer and the coating. The coating preferentially allows p-polarized light to pass through. Therefore, when the selective polarizing layer is switched to a higher transmittance for p-polarized light, the transmittance can be increased. When the selective polarizing layer is switched to a higher transmittance for s-polarized light, the transmittance may be reduced. In both states, the region remains transparent and therefore does not become milky turbid as in PDLC in the voltage-free state. Furthermore, a particular advantage of this arrangement is that coatings that selectively allow p-polarized light to pass through are particularly effective when the incident light has a large angle of incidence. This is the case in windshields when the sun is low, and thus the glare protection effect is most effective when it is needed.

The coating preferentially allowing p-polarized light to pass comprises at least one silver layer, preferably two, three, four or more silver layers. The coating is preferably a thin layer stack and includes one or more dielectric layers between each silver layer.

In a preferred embodiment, the coating comprises at least two functional layers on top of each other and each functional layer comprises at least

-an anti-reflection layer,

-a first adaptation layer over the anti-reflection layer, and

-a silver layer over the first adaptation layer, wherein

At least one functional layer has an antireflection layer, at least

-comprises a layer of dielectric material having a refractive index of less than 2.1, and

-a layer of an optically high refractive index material having a refractive index greater than or equal to 2.1.

If the first layer is arranged above the second layer, this means that the first layer is arranged further away from the substrate than the second layer. If the first layer is arranged below the second layer, this means in the sense of the present invention that the second layer is arranged further away from the substrate than the first layer. The uppermost functional layer is the one having the greatest distance from the substrate. The lowermost functional layer is the one having the smallest distance to the substrate.

If the first layer is disposed above or below the second layer, this does not necessarily mean that the first and second layers are in direct contact with each other. One or more other layers may be disposed between the first layer and the second layer unless specifically excluded.

The refractive index values shown are measured at a wavelength of 550 nm. The refractive index can be determined, for example, by ellipsometry. Ellipsometers are commercially available, for example from Sentech corporation. The refractive index of the upper or lower dielectric layer is preferably determined by first depositing it as a monolayer on the substrate and then measuring the refractive index by ellipsometry. Dielectric layers having a refractive index of at least 2.1 and methods for their deposition are known to those skilled in the art of thin layers. Physical vapor deposition methods, in particular magnetron sputtering methods, are preferably used.

The silver layer preferably has a layer thickness of 8 nm to 25 nm, particularly preferably 13 nm to 19 nm. This is particularly advantageous for transparency and color neutrality of the coating and for a high transmission of p-polarized light compared to s-polarized light.

Each functional layer of the coating comprises an anti-reflective layer. In particular, antireflective layers result in a reduction in reflectivity and thus increase the transmission of the coating in the visible spectral range.

The layer of optically high refractive index material preferably comprises at least one silicon-metal-mixed nitride, particularly preferably a silicon-zirconium-mixed nitride. The silicon-zirconium mixed nitride preferably has a dopant. The layer of optically high refractive index material may for example comprise an aluminium-doped silicon-zirconium-mixed nitride (SiZrNx: al).

The layer of dielectric material preferably comprises at least one oxide, such as tin oxide, and/or a nitride, particularly preferably silicon nitride. The layer of dielectric material preferably has a layer thickness of 5 nm to 63 nm.

A cover layer is preferably arranged above the uppermost functional layer. The cover layer protects the layers arranged therebelow from corrosion. The cover layer is preferably dielectric. For example, the capping layer may comprise silicon nitride and/or tin oxide.

Each functional layer of the coating preferably comprises at least one smoothing layer. The smoothing layer is arranged below the first adaptation layer, preferably between the layer of optically high refractive index material and the first adaptation layer. The smoothing layer is preferably in direct contact with the first adaptation layer. The smoothing layer brings about an optimization, in particular a smoothing, of the surface for the subsequently applied, overlying conductive layer. The conductive layer deposited on the smoother surface has a higher transmittance.

For example, the smoothing layer may comprise at least one oxide of one or more of the elements tin, silicon, titanium, zirconium, hafnium, zinc, gallium, and indium. The layer thickness of the smoothing layer is preferably from 3 nm to 20 nm, particularly preferably from 4 nm to 12 nm. The refractive index of the smoothing layer is preferably less than 2.2.

The first adaptation layer and/or the second adaptation layer preferably contain 0<δ<0.01 Zinc oxide ZnO _1-δ . The first adaptation layer and/or the second adaptation layer further preferably comprise a dopant. For example, the first and/or second matching layer may comprise aluminum doped zinc oxide. The layer thickness of the first and second matching layers is preferably from 3 nm to 20 nm, particularly preferably from 4 nm to 12 nm.

The at least one functional layer preferably comprises at least one barrier layer. The barrier layer is in direct contact with the silver layer. The functional layer may also comprise two barrier layers, wherein preferably one barrier layer is arranged directly above the silver layer and one barrier layer is arranged directly below the silver layer. Each functional layer particularly preferably comprises at least one such barrier layer. The barrier layer preferably comprises niobium, titanium, nickel, chromium and/or alloys thereof, particularly preferably a nickel-chromium alloy. The layer thickness of the barrier layer is preferably from 0.1 nm to 2 nm. Thereby achieving good results. The barrier layer directly below the silver layer serves in particular to stabilize the electrically conductive layer during temperature treatment and to improve the optical quality of the electrically conductive coating. The barrier layer directly over the conductive layer prevents the sensitive conductive layer from coming into contact with the oxidizing reactive atmosphere during deposition of subsequent layers, for example a second adaptation layer preferably comprising zinc oxide, by reactive cathode sputtering.

In another preferred embodiment of the present invention, the selective polarizing layer may have a liquid crystal layer, and the selective polarizing layer is preferably a PDLC layer.

The active layer of the PDLC layer contains liquid crystals embedded in a polymer matrix. If no voltage is applied to the planar electrodes, the liquid crystals are aligned in a disordered manner, which results in strong scattering of light transmitted through the active layer. If a voltage is applied to the planar electrodes, the liquid crystals are aligned in a common direction, and the transmittance through the active layer increases.

PDLC layers are commercially available as multilayer films and have two outer support films in addition to the active layer and planar electrodes. The PDLC layer may thus be incorporated as a laminate film into the composite glass sheet and embedded into the thermoplastic interlayer. The PDLC layer preferably has an edge seal. The edge seal covers the side edges of the PDLC layer circumferentially and prevents in particular the chemical components of the thermoplastic layer, for example plasticizers, from diffusing into the active layer.

In yet another embodiment of the present invention, the selective polarizing layer can adjust the proportion of p-polarized light or s-polarized light in a variable manner in at least two or more levels. This means that the proportion of p-polarized light or s-polarized light transmitted through the selective polarizing layer is variable in two or more levels.

The selective polarizing layer is joined to the first substrate by a region of the thermoplastic interlayer and is joined to the second substrate by a region of the thermoplastic interlayer. In general, the thermoplastic intermediate layer is formed from at least one first and one second thermoplastic layer, which are stacked on top of one another in a planar fashion and are laminated to one another, with the selective polarization layer being interposed between the two thermoplastic layers. The regions of these layers that overlap the selective polarization layer now form the regions that join the selective polarization layer to the glass sheet. In other areas of the glass sheet where the thermoplastic layers are in direct contact with each other, they may fuse upon lamination, so that the two original layers may no longer be identifiable, but rather a homogeneous thermoplastic interlayer is present.

The thermoplastic interlayer or thermoplastic layer preferably comprises at least polyvinyl butyral (PVB), ethylene Vinyl Acetate (EVA) and/or Polyurethane (PU), particularly preferably PVB.

The thickness of the or each thermoplastic layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, in particular from 0.3 mm to 0.5 mm, for example 0.38 mm.

The thermoplastic layer may be formed, for example, from a single thermoplastic film. The thermoplastic layer can also be formed by parts of different thermoplastic films whose side edges lie against one another.

In a preferred embodiment, the coating is disposed directly on one of the substrates. The coating is preferably applied to the surface of the glass plate by Physical Vapor Deposition (PVD), particularly preferably by sputtering ("sputtering"), very particularly preferably by magnetic field-assisted sputtering ("magnetron sputtering"). The advantage of direct application to the substrate is that no additional stresses are introduced into the glass sheet as a result of local thickening of the glass sheet when using the carrier film. Alternatively, the coating is preferably arranged on a carrier film, preferably made of PET, which can be joined to one of the substrates by means of an adhesive.

In a preferred embodiment, the coating is arranged on the surface of the transparent substrate facing the thermoplastic intermediate layer. The coating is thereby advantageously protected against damage and corrosion.

In a preferred embodiment, the composite glass sheet comprises two coatings, both coatings preferentially allowing p-polarized light to pass through. Thereby further enhancing the selective effect of p-polarized light relative to s-polarized light. The two coatings are preferably arranged between the first and second substrates, thereby protecting them from corrosion and damage. The two coatings may be identical or have different layer structures. One or both coatings may be disposed directly on the substrate, or one coating may be disposed on the substrate and one coating may be disposed on the carrier film. Particularly preferably, the first coating is arranged on a first substrate and the second coating is arranged on a second substrate.

The first and second substrates preferably comprise glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, aluminosilicate glass, soda-lime glass or clear plastic, preferably rigid clear plastic, in particular polycarbonate or polymethyl methacrylate. The substrate may be clear or colored or tinted.

The thickness of the substrate can vary widely and is therefore adapted to the requirements of the respective case. The substrate preferably has a thickness of 0.5 mm to 5 mm, particularly preferably 1 mm to 3 mm.

In a preferred embodiment, the composite glass pane is a vehicle glass pane for a land, water and air vehicle, preferably a motor vehicle glass pane, particularly preferably a windshield pane or a roof pane or side panes.

The vehicle glazing is provided for isolating the interior space from the external environment in a window opening of the vehicle. The inner glass sheet refers to a glass sheet of the glass sheet facing the interior space (vehicle interior space). The outer glass sheet refers to the glass sheet facing the outside environment.

In a particularly preferred embodiment, the composite glass sheet is a windshield glass sheet and the selective polarizing layer is disposed only in a sub-region of the composite glass sheet above the central field of view.

In a particularly preferred embodiment, the composite glass sheet is a windshield sheet and the coating is disposed only in a sub-region of the composite glass sheet above the central field of view (B). This saves material and can therefore be realized cost-effectively.

The windshield panel has an upper edge and a lower edge and two side edges extending between the upper edge and the lower edge. The top edge denotes that edge which is arranged to point upwards in the mounted position. The lower edge denotes that edge which is arranged to point downwards in the mounted position. The upper edge is commonly referred to as the top edge and the lower edge is referred to as the engine edge. The top glass plate has corresponding edges. Here, the upper edge corresponds to the edge directed toward the windshield panel, and the lower edge corresponds to the edge directed toward the rear glass panel.

The windscreen panels have a central field of view, which puts high demands on their optical quality. The central field of view must have a high light transmission (typically greater than 70%). The central field of view is in particular that field of view which is known to the person skilled in the art as B-field of view, B-field of view or B-field of view. The B field and its technical requirements are specified in european union economic commission (UN/ECE) No. 43 regulation (ECE-R43, "uniform conditions for approval of safety glazing materials and their installation in vehicles"). There, the B-field is defined in appendix 18.

The selective polarizing layer is preferably arranged above the central viewing field (B viewing field). This means that the selective polarization layer is arranged in the region between the central field of view and the top edge of the windscreen panel. The selective polarizing layer need not cover the entire area, but is located completely within this area and does not protrude into the central field of view. In other words, the selective polarizing layer has a smaller distance from the upper edge of the windscreen panel than the central viewing zone. Thus, the transmission of the central field of view is not affected by the selective polarizing layer being located at a similar position as when a conventional mechanical sun visor is in a flipped down state. The selective polarizing layer together with the coating thus assumes the function of a sun visor.

The top and side edges of the selective polarizing layer are preferably covered by an opaque cover print when viewed transparently through the windshield or top glass panel. The windscreen panel usually has a circumferential covering print made of opaque enamel, which serves in particular to protect the adhesive used for mounting the windscreen panel from uv radiation and to visually conceal it. The perimeter cover print preferably also serves to cover the top and side edges of the selective polarizing layer as well as the required electrical connections. At this point, the selective polarizing layer is advantageously integrated into the appearance of the vehicle glazing, and only the lower edge may be visible to an observer. Preferably, both the outer and inner glass plates have cover printing to prevent two-sided perspective.

The selective polarizing layer and the coating may also have indentations or holes, for example in the area of a so-called sensor window or camera window. These areas are arranged to be equipped with sensors or cameras whose function may be impaired by selectively polarizing layers and/or coatings in the beam path, such as rain sensors.

The selective polarization layer is preferably arranged over the entire width of the windscreen or roof glass pane, minus the edge regions of the two sides, which have a width of, for example, 2 mm to 20 mm. The selective polarization layer also preferably has a distance of, for example, 2 mm to 20 mm from the upper edge. The selective polarizing layer is thus encapsulated within the intermediate layer and protected from contact with the surrounding atmosphere and from corrosion.

The glass sheet and thermoplastic interlayer may be clear or tinted or dyed as long as the windshield has sufficient light transmission in the central viewing zone, preferably at least 70% in the main a see-through zone according to ECE-R43. These limitations do not apply to the top glass plate.

In a preferred embodiment, a pigmented intermediate layer may be used in the area of the selective polarizing layer to assist the glare protection function. The intermediate layer may be formed from a single thermoplastic film, wherein the coloured or dyed areas are produced by local colouring or dyeing. Such a film can be obtained, for example, by coextrusion. Alternatively, uncolored film portions and colored or dyed film portions may be combined to form the thermoplastic layer.

The colored or dyed areas may be uniformly colored or dyed, i.e. have a position-independent transmittance. However, the coloring or dyeing may also be non-uniform, in particular a transmittance distribution may be achieved. In one embodiment, the transmittance in the colored or dyed area decreases at least in sections with increasing distance from the upper edge. This avoids sharp edges of the coloured or tinted areas, so that the transition from the sun visor to the transparent area of the windscreen panel is gradual, which appears more aesthetically appealing.

Brief Description of Drawings

Embodiments of the present invention are described by way of example with reference to the accompanying drawings, in which:

figure 1 is a schematic view of an aspect of the present invention,

figure 2 is a schematic cross-sectional view of an arrangement for an embodiment of the invention,

figure 3 is a graph of transmittance according to a first exemplary embodiment of the present invention,

FIG. 4 is a graph of transmittance according to another exemplary embodiment of the present invention, an

Fig. 5 is a graph of transmittance according to still another exemplary embodiment of the present invention.

The invention is explained in more detail below with reference to the drawings. It should be noted here that different aspects are described, which can be used individually or in combination. That is, various aspects may be used with different embodiments of the invention, unless explicitly indicated as a mere alternative.

Furthermore, for the sake of simplicity, in the following, reference is generally always made to only one entity. However, the invention may also have a plurality of entities involved, respectively, unless explicitly stated otherwise. In this regard, use of the words "a" and "an" should only be taken to imply that at least one entity is used in a simple embodiment.

If methods are described below, the various steps of the methods can be arranged in any order and/or combined unless otherwise indicated by context. Furthermore, these methods may be combined with each other unless explicitly indicated otherwise.

Descriptions with numerical values should not generally be understood as precise values, but include tolerances of +/-1% to +/-10%.

A reference to a standard or specification or guideline should be understood as a reference to a standard or specification or guideline which applies at the time of filing and/or-whenever priority is claimed-also applies at the time of priority filing. However, this should not be construed as a general exclusion of the availability of subsequent or alternative standards or specifications or guidelines.

FIG. 1 shows a composite glass sheet having a first substrate.

For the sake of understanding below, one of the two substrates 1 and 3 in fig. 1 may be referred to.

The composite glass sheet has a selectively adjustable transmittance in sections.

To this end, the substrate has at least one selective polarizing layer 4a and a coating 4b.

The order of the layers can be selected appropriately here. It is assumed below that the layer sequence is chosen such that the selective polarization layer 4a is arranged closer to the light source S, for example the sun, than to the user U. In contrast, the coating 4b is arranged closer to the user U than to the light source S. Of course, this can also be used in reverse without thereby changing the inventive idea. The coating 4b and the selective polarizing layer 4a are stacked on each other in a surface form. They are therefore arranged in the same region on the glass plate, so that the light which strikes the selective polarization layer also strikes the coating. The coating 4b may also be arranged in a larger area than in the area of the selective polarizing layer alone.

In fig. 1, the coating 4b is applied directly onto the second substrate 3, for example by means of a PVD (physical vapor deposition) method. Alternatively, the coating 4b and the selective polarization layer 4a can also be made directly adjacent to one another, as shown in fig. 2, and then embedded as a common layer 4 in the thermoplastic intermediate layer 2. In this case, for example, a coated PET film is suitable for the coating 4b.

The selective polarizing layer 4a is variable such that it preferentially allows s-polarized or p-polarized light to pass through. Intermediate steps or smooth transitions may also be implemented here.

In contrast, the coating 4b preferentially allows p-polarized light to pass through.

The thermoplastic interlayer 2 joins the first substrate 1 to the second substrate 3 and is arranged over the entire face between the two substrates 1 and 3. The thermoplastic intermediate layer 2 is also arranged in the region of the selective polarization layer 4 a. The thermoplastic intermediate layer 2 may consist of one or more separate sub-layers.

It should be noted that other layers for different purposes, such as heating layers, antennas, anti-reflection coatings or thermal barriers, etc. may also be applied on the substrate.

The invention thus solves the technical problem. In particular, the transmission can now be controlled in a targeted and cost-effective manner. This is possible in particular when the substrate is, for example, a glass plate in a vehicle and the light, the light source S, impinges on the substrate at a non-perpendicular angle. This is schematically illustrated in fig. 1, where incident light from a light source S impinges on the substrate arrangement. Depending on the control of the selective polarization layer 4a, it is now possible to control whether (or how much) p-polarized light still impinges on the coating 4b and can thus also penetrate in front of the user U. The effect of the coating 4b is particularly effective at larger angles of incidence. The angle α represents the angle between the normal to the surface of the glass sheet (90 ° to the plane of the surface of the glass sheet) and the solar radiation S. The coating 4b works best at an angle α of 10 ° to 80 °, particularly well at 50 ° to 75 °, very particularly well at 40 ° to 70 °. This describes the situation when the vehicle driver U is in the low position of the sun.

For example, effective glare protection against solar radiation can be provided and thus the safety of the traffic participants is increased.

In particular, the substrate arrangement can be used, for example, as a glare shield (shadow band) in a windshield or other glass pane, for example a glass roof, wherein the glare shield effect can be improved for passengers at the rear of the vehicle. The glare protection effect of the display (display) in the area of the dashboard can also be improved by the substrate arrangement according to the invention.

Unlike the consideration of using PDLC so far, where switching to a turbid state is necessary in order to reduce the transmittance of the PDLC element, by the present invention the turbid state can be avoided to reduce the transmittance, since the selective polarizing layer 4a can be switched from a particular transparent state with high transmittance to (at least one) other transparent state with lower transmittance.

In a preferred embodiment of the invention, the coating 4b has at least one silver layer. The coating 4b preferably has two, three, four or more silver layers.

In another preferred embodiment of the present invention, the selective polarizing layer 4a may have a liquid crystal layer, and the selective polarizing layer 4a is preferably a PDLC layer.

In yet another embodiment of the present invention, the selective polarization layer 4a can adjust the proportion of transmitted p-polarized light or s-polarized light in a variable manner in at least two or more levels.

The above-described solution can be used here in a diverse manner. It is known that visual comfort is a major aspect of glazing. Visual comfort here includes, together, aspects of light reflectance, light transmittance, color fidelity, and aesthetics. However, visual comfort also includes aspects such as privacy, i.e. the possibility of being able to (selectively) look through in only one direction.

It is important here that such a visual comfort function can be switched.

With the proposed solution, a coating 4b is proposed which allows more p-polarized light to pass than s-polarized light. Furthermore, the device has a selective polarization layer 4a, which makes the polarization of the incident light selectable. By the combination of the selective polarizing layer 4a and the coating 4b, in particular on or in a glazing, in particular a composite (vitreous) glass pane, the light transmission can be adjusted by a factor of up to 3 by selecting the direction of polarization in the selective polarizing layer 4 a.

Without limiting the generality, the coating 4b can be understood to refer not only to a direct coating but also to a polarizing film.

Without limiting the generality, the invention can be used for sub-areas as well as for the entire glass sheet. The invention can of course also be used in other fields than vehicle technology, for example for architectural glazing.

For example, coating 4b can also be a coating manufactured by the applicant under the name Climacoat, whose optical properties relating to p-polarization and s-polarization are shown in FIG. 3 (when illuminated at an angle of 66 deg.). This results in a ratio of the transmission of p-polarized light to the transmission of s-polarized light (at 66 ° incidence relative to normal) of about 1.9.

The angle of 66 deg. with respect to the normal corresponds approximately to what may occur in a windscreen panel. In this case, the transmittance of p-polarized light is about 72.2%, and the transmittance of s-polarized light is about 38.6%. If one of these polarizations is selected by the selective polarizing layer 4a ", i.e. for example if the liquid crystal particles are aligned approximately parallel to the s-or p-polarization and then rotated by 90 ° into the respective other polarization by applying a voltage, the transmission can be abruptly switched by a factor of 1.9. By adding colored regions, the transmittance can be additionally reduced.

Fig. 4 shows an embodiment similar to that of fig. 3. The silver layer(s) is now increased, unlike the sequence of steps in fig. 3. In this case, the transmittance of p-polarized light is about 32.1%, and the transmittance of s-polarized light is about 10.3%. This results in a ratio of the transmission of p-polarized light to the transmission of s-polarized light (at 66 ° incidence with respect to the normal) of about 3.1.

Such a structure may be advantageously used in areas where the total transmission (in terms of legislation) is not important, for example in vehicle roofs/skylights, so that for example passengers in rear seats are not dazzled by sunlight. It can also be used effectively in the upper region of the windscreen panel to thus avoid glare due to reflections on the dashboard or on the meters/displays in the dashboard region, which may occur under non-vertical solar radiation.

In fig. 5 an embodiment similar to that of fig. 3 and 4 is shown. For example, coating 4b can also be a coating manufactured by the applicant under the name of Climacoat, whose optical properties related to p-polarization and s-polarization are shown in FIG. 5 (when illuminated at an angle of 66 deg.). This results in a ratio of the transmission of p-polarized light to the transmission of s-polarized light (at 66 ° incidence with respect to the normal) of about 1.8. The coating had 4 silver layers.

The following illustrates an exemplary layer structure of the drawings in a table format.

As mentioned before, the transition between s-polarization and p-polarization can be achieved smoothly or stepwise by appropriate control, so that the transmission can be changed in steps or steplessly between the two extremes.

Advantageously, the invention can also be used with p-polarized sunglasses of eyeglasses, since the sunglasses transmit p-polarized light more strongly than s-polarized light.

List of reference numerals

1. A first substrate

2. Intermediate layer

3. Second substrate

4a selective polarizing layer

4b coating

S light source

And U, users.

Claims (12)

1. Composite glass pane having a segmentally adjustable selective transmission, comprising at least

-a first substrate (1) and a second substrate (3) mutually joined by a thermoplastic intermediate layer (2),

-a selective polarizing layer (4 a) which is variable such that it preferentially allows s-polarized or p-polarized light to pass through, and

-a coating (4 b) preferentially allowing p-polarized light to pass, wherein

The selectively polarizing layer (4 a) and the coating (4 b) are arranged on top of each other in a surface-shaped manner, and the coating (4 b) has at least one silver layer.

2. Composite glass pane according to claim 1, characterised in that the coating (4 b) has at least two silver layers, preferably three, four or more silver layers.

3. Composite glass pane according to claim 1 or 2, characterised in that the selective polarisation layer (4 a) is a liquid crystal layer, preferably a PDLC (polymer dispersed liquid crystal) layer.

4. Composite glass pane according to any one of the preceding claims, characterised in that the selective polarisation layer (4 a) can adjust the proportion of p-polarised or s-polarised light in a variable manner in at least two or more levels.

5. Composite glass pane according to any one of the preceding claims, characterised in that the selective polarisation layer (4 a) is embedded in the thermoplastic interlayer (2).

6. Composite glass pane according to any one of the preceding claims, wherein the coating (4 b) is arranged directly on the substrate (1, 3).

7. Composite glass pane according to claim 6, wherein the coating is applied to the substrate (1, 3) by Physical Vapour Deposition (PVD), preferably by magnetic field assisted cathode sputtering.

8. Composite glass pane according to any one of the preceding claims, wherein the composite glass pane comprises two coatings (4 b) preferentially allowing p-polarized light to pass, which are arranged between the first substrate (1) and the second substrate (3).

9. Composite glass pane according to claim 8, wherein the first coating (4 b) is arranged on the first substrate (1) and the second coating (4 b) is arranged on the second substrate (3).

10. The composite glass pane according to any one of the preceding claims, characterised in that the composite glass pane is a vehicle glass pane, preferably an automotive glass pane, particularly preferably a windscreen pane, a side glass pane or a roof glass pane.

11. Composite glass pane according to the preceding claim, characterised in that it is a windscreen pane and in that the selective polarizing layer (4 a) is arranged only in a sub-region above a central field of view (B) of the composite glass pane.

12. A composite glass pane according to claim 11, characterised in that the composite glass pane is a windscreen pane and the coating (4B) is arranged only in a sub-region above a central field of view (B) of the composite glass pane.

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