LAMINATED GLAZING

Abstract

A laminated glazing includes first and second sheets of glazing material joined by an interlayer structure including a first sheet of adhesive interlayer material having a first (window) region for positioning a (LIDAR) sensor thereon and a second region that is a through-vision region. The first region comprises a first portion and the second region comprises a second portion of a major surface of the first sheet of glazing material. The laminated glazing has a first transmittance of electromagnetic radiation transmitted by the sensor at the first portion that is higher than a second transmittance at the second portion. It also has a visible light transmission greater than 70% at the second portion. The separation of the first and second glazing material sheets varies in at least one direction and/or the first sheet of adhesive comprises heat absorbing particles such as lanthanum hexaboride particles or certain metal-doped metal oxide particles.

Claims

1. A laminated glazing comprising a first sheet of glazing material joined to a second sheet of glazing material by an interlayer structure therebetween, the interlayer structure comprising at least a first sheet of adhesive interlayer material, each of the first and second sheets of glazing material having a respective first major surface and second opposing major surface; the laminated glazing being arranged such that the second major surface of the first sheet of glazing material faces the first major surface of the second sheet of glazing; the laminated glazing having a first region for positioning a sensor thereon and a second region being a through-vision region, the first region of the laminated glazing comprising a first portion of the first major surface of the first sheet of glazing material and the second region of the laminated glazing comprising a second portion of the first major surface of the first sheet of glazing material; the sensor being arranged to transmit a beam of electromagnetic radiation having at least a first wavelength towards the first portion of the first major surface of the first sheet of glazing material for transmission through the laminated glazing and out of the second major surface of the second sheet of glazing material; wherein at normal incidence to the first portion of the first major surface of the first sheet of glazing material, the laminated glazing has a first transmittance at the first wavelength and at normal incidence to the second portion of the first major surface of the first sheet of glazing material, the laminated glazing has a second transmittance at the first wavelength, the first transmittance of the laminated glazing being higher than the second transmittance of the laminated glazing; and wherein at normal incidence to the second portion of the first major surface of the first sheet of glazing material, the second region of the laminated glazing has a visible light transmission (CIE Illuminant A) of greater than 70%; further wherein the separation of the first major surface of first sheet of glazing material and the second major surface of the second sheet of glazing material in at least the second region of the laminated glazing varies in at least a first direction, and/or the first sheet of adhesive interlayer material comprises heat absorbing particles selected from the group consisting of aluminium-doped tin oxide particles, gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminium-doped zinc oxide particles (AZO particles), niobium-doped titanium oxide particles, sodium-doped tungsten oxide particles, caesium-doped tungsten oxide particles (CWO particles), thallium-doped tungsten oxide particles, rubidium-doped tungsten oxide particles, tin-doped zinc oxide particles and silicon-doped zinc oxide particles, lanthanum hexaboride (LaB.sub.6) particles, metal-doped tungsten oxide particles.

2. A laminated glazing according to claim 1, wherein the first sheet of adhesive interlayer material is wedge shaped and contains heat absorbing particles selected from the group consisting aluminium-doped tin oxide particles, indium-doped tin oxide particles, antimony-doped tin oxide particles (ATO particles), gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminium-doped zinc oxide particles (AZO particles), niobium-doped titanium oxide particles, sodium-doped tungsten oxide particles, caesium-doped tungsten oxide particles (CWO particles), thallium-doped tungsten oxide particles, rubidium-doped tungsten oxide particles, tin-doped indium oxide particles, tin-doped zinc oxide particles and silicon-doped zinc oxide particles, lanthanum hexaboride (LaB.sub.6) particles and metal-doped tungsten oxide particles.

3. A laminated glazing according to claim 1, wherein the first sheet of adhesive interlayer material comprises heat absorbing particles being lanthanum hexaboride (LaB.sub.6) particles and/or metal-doped tungsten oxide particles.

4. A laminated glazing according to claim 1, wherein the first and/or second sheet of glazing material comprises less than 0.1% by weight Fe.sub.2O.sub.3.

5. A laminated glazing according to claim 1, wherein the sensor comprises a LIDAR.

6. A laminated glazing according to claim 1, wherein the first wavelength is between 750 nm and 1650 nm.

7. A laminated glazing according to claim 1, wherein the first sheet of adhesive interlayer material is monolithic or has a multi-layer construction.

8. A laminated glazing according to claim 1, wherein the first sheet of adhesive interlayer material and/or the interlayer structure is wedge shaped.

9. A laminated glazing according to claim 1, wherein the first sheet of adhesive interlayer material or the interlayer structure has a thickness between 0.3 mm and 2.3 mm.

10. A laminated glazing according to claim 1, wherein the first sheet of adhesive interlayer material comprises polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), poly vinyl chloride (PVC), polyurethane (PU), acoustic modified PVB or a liquid curable acrylic resin.

11. A laminated glazing according to claim 1, wherein the first and/or second sheet of glazing material has a thickness less than 5 mm and/or a thickness greater than 0.3 mm.

12. A laminated glazing according to claim 1, wherein the first transmittance is greater than 80%.

13. A laminated glazing according to claim 1, wherein the first portion of the first major surface of the first sheet of glazing material comprises an anti-reflective coating thereon.

14. A laminated glazing according to claim 13, wherein the anti-reflective coating covers the entire first portion of the first major surface of the first sheet of glazing material.

15. A laminated glazing according to claim 13, wherein the anti-reflective coating covers at least a part of the second portion of the first major surface of the first sheet of glazing material.

16. A laminated glazing according to claim 13, wherein the anti-reflective coating increases the first transmittance and/or transmittance at normal incidence to the first portion of the first sheet of glazing material at one or more wavelength.

17. A laminated glazing according to claim 13, wherein the anti-reflective coating increases the first transmittance by at least 1%.

18. A laminated glazing according to claim 13, wherein the first transmittance is between 80% and 95%.

19. A laminated glazing according to claim 1, wherein at normal incidence to the second portion of the first major surface of the first sheet of glazing material, the second region of the laminated glazing has a total transmitted solar (TTS %) measured using ISO 13837:2008 Convention A (with outside surface wind velocity v.sub.1 of approximately 4 m/s) of less than 65%.

20. A laminated glazing according to claim 1, wherein at normal incidence to the first portion of the first major surface of the first sheet of glazing material, the first region of the laminated glazing has a visible light transmission (CIE Illuminant A) greater than the visible light transmission (CIE Illuminant A) of the second region of the laminated glazing when measured at normal incidence to the second portion of the first major surface of the first sheet of glazing material.

21. A laminated glazing according to claim 1, wherein the interlayer structure facing at least part of a first portion of the second major surface of the first sheet of glazing material, the first portion of the second major surface of the first sheet of glazing material being opposite the first portion of the first major surface of the first sheet of glazing material, comprises a second sheet of interlayer material different to the first sheet of adhesive interlayer material such that the first sheet of adhesive interlayer material is part of the second region and the second sheet of interlayer material is part of the first region and wherein the second sheet of interlayer material having a higher transmittance at the first wavelength compared to the transmittance at the first wavelength of the first sheet of adhesive interlayer material.

22. A laminated glazing according to claim 21, wherein the second sheet of interlayer material is positioned in an opening in the first sheet of adhesive interlayer material.

23. A laminated glazing according to claim 21, wherein the second sheet of interlayer material has first and second opposing major surfaces, the first major surface of the second sheet of interlayer material facing the first sheet of glazing material and the second major surface of the second sheet of interlayer material facing the second sheet of glazing material and wherein the first and/or second major surface of the second sheet of interlayer material is provided with an adhesive.

24. A laminated glazing according to claim 21, wherein the second sheet of interlayer material is an adhesive sheet of interlayer material.

25. A method of making a laminated glazing, the laminated glazing having a first region for a window for a sensor, the sensor being operable at at least a first wavelength, the method comprising: (i) providing a first sheet of glazing material and a second sheet of glazing material and an interlayer structure for positioning between the first and second sheets of glazing material, the interlayer structure comprising a first sheet of adhesive interlayer material and a second sheet of interlayer material, the second sheet of interlayer material having a higher transmittance at the first wavelength compared to the transmittance of the first sheet of adhesive interlayer material at the first wavelength; the interlayer structure having a wedge shape and/or containing heat absorbing particles, the heat absorbing particles being selected from the group consisting of aluminium-doped tin oxide particles, gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminium-doped zinc oxide particles (AZO particles), niobium-doped titanium oxide particles, sodium-doped tungsten oxide particles, caesium-doped tungsten oxide particles (CWO particles), thallium-doped tungsten oxide particles, rubidium-doped tungsten oxide particles, tin-doped zinc oxide particles and silicon-doped zinc oxide particles, lanthanum hexaboride (LaB.sub.6) particles, metal-doped tungsten oxide particles; (ii) arranging the interlayer structure between the first and second sheets of glazing material such that at least a portion of the second sheet of interlayer material forms part of the window for the sensor; and (iii) using suitable lamination conditions to join the first sheet of glazing material to the second sheet of glazing material by the interlayer structure.

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Description

[0103] The invention will now be described with reference to the following figures (not to scale) in which,

[0104] FIG. 1 shows a schematic isometric representation of a vehicle windscreen incorporating a laminated glazing according to the present invention; and

[0105] FIG. 2 shows a schematic cross-sectional view of the vehicle windscreen of FIG. 1 through the line A-A′;

[0106] FIG. 3 shows a schematic exploded cross-sectional view of the windscreen of FIG. 1 through the line A-A′ with the head up display projector included.

[0107] With reference to the figures, FIG. 1 shows a schematic isometric representation of a vehicle windscreen 1 when installed in a vehicle (not shown). The vehicle windscreen 1 has a sensor mounted on the inner facing surface 10 thereof. The sensor 3 is included in a suitable housing 4 that is suitably mounted on the inner facing surface 10. The sensor faces the inner facing surface 10 to define a first region of the windscreen 1 because this region of the windscreen acts as a window for the sensor 3. The preferred sensor 3 comprises a LIDAR. In an alternative embodiment to that shown in FIG. 1, the sensor 3 is in mechanical communication with a mount assembly (not shown), the mount being attached directly to the inner facing surface 10 of the windscreen. The mount assembly may have one or more functional element connected or mounted thereto, for example a rear view mirror or rain sensor.

[0108] The sensor 3 emits a sensing beam 15 through the vehicle windscreen 1 to strike an object 17 remote from the vehicle. A beam 19 is reflected off the object 17 to pass through the windscreen 1 for detection by the sensor 3. In this example the sensing beam 15 and the reflected beam are both infrared beams having a wavelength between 750 nm and 1650 nm, for example 905 nm.

[0109] Mounted below the vehicle windscreen 1 is a head up projector system 5. The head up projector system 5 is arranged to direct a beam of light 7 towards the inner facing surface 10 of the windscreen 1.

[0110] The beam of light 7 reflects off the inner facing surface 10 as reflected beam 9 towards an observer 13. The observer 13 sees a virtual image 14 (represented by the letters “abc”) beyond the outer surface of the vehicle windscreen 1.

[0111] The observer 13 also sees the road ahead through the windscreen 1 and this part of the windscreen acts as a window for the observer and is a second region of the windscreen 1. The second region of the windscreen 1 is a through-vision region.

[0112] With particular reference to FIGS. 2 and 3, the vehicle windscreen 1 comprises a first sheet of glass 11 joined to a second sheet of glass 21 by means of interlayer structure 31.

[0113] The first sheet of glass 11 has a first major surface 10 and an opposing second major surface 12. The second sheet of glass 21 has a first major surface 20 and an opposing second major surface 22.

[0114] The interlayer structure 31 has a first major surface 30 and an opposing second major surface 32.

[0115] The first sheet of glass 11 has a soda-lime-silica composition with an iron oxide content of 0.005% by weight expressed as Fe.sub.2O.sub.3. The thickness of the first sheet of glass 11 is 2.1 mm but may be in the range 1.6 mm to 5 mm.

[0116] The second sheet of glass 21 also has a soda-lime-silica composition with an iron oxide content of 0.005% by weight expressed as Fe.sub.2O.sub.3. The thickness of the second sheet of glass is also 2.1 mm but may be in the range 1.6 mm to 5 mm. It is preferred that the second sheet of glass 21 is thicker than the first sheet of glass 11.

[0117] The interlayer structure 31 is wedge shaped, being thicker at the upper region 35 compared to the lower region 37. As is known in the art, the use of such wedged interlayer structures is useful to reduce the double image that may occur with head up display systems as light can reflect off the air/glass interface defined by the first major surface 10 of the first sheet of glass 11 and the glass/air interface defined by the second major surface 22 of the second sheet of glass 21. In this example the wedge extends in a first direction from the upper edge of the vehicle windscreen 1 to the lower edge of the vehicle windscreen 1. When the laminated glazing 1 is installed in a vehicle, the first direction is parallel to the vertical i.e. as determined using a plumb line.

[0118] The first sheet of PVB 31′ has a wedge angle 36.

[0119] The interlayer structure 31 comprises a sheet of PVB 31′ including heat absorbing particles, the heat absorbing particles in this example caesium doped tungsten oxide particles (CWO particles). Only one composition of heat absorbing particle may be in the sheet of PVB 31′, or there may be heat absorbing particles having two or more different compositions.

[0120] In accordance with an embodiment of the present invention, the sheet of PVB 31′ has an opening therein such that the sensor 3 faces the opening. Positioned in the opening is a sheet of PVB 33 that does not contain heat absorbing particles. The sheet of PVB 33 may be sized to have the same degree of wedge as the sheet of PVB 31′. That is, the sheet of PVB has a wedge angle 38 that is same as the wedge angle 36. A suitable material for the sheet of PVB 33 is a conventional clear PVB.

[0121] Both sheets of PVB 33, 31′ may comprise other materials conventionally found in such interlayers, such as ultra-violet ray shielding agents, oxidation inhibitors, heat absorbing dyes and plasticizers.

[0122] In operation, the sensor 3 transmits the sensing beam 15 through the first sheet of glass 11, the sheet of PVB 33 and the second sheet of glass 21.

[0123] Since the sheet of PVB 33 does not contain heat absorbing particles, the infrared transparency of the sheet of PVB 33 is much higher than the infrared transparency of the sheet of PVB 31′. This ensures the sensing beam 15 and/or the reflected beam 19 are not significantly attenuated upon passing through the interlayer structure 31.

[0124] The transmittance of the laminated glazing 1 in different regions thereof at the wavelength (or wavelengths) of the sensing beam 15 may be determined using a conventional double beam spectrophotometer.

[0125] Furthermore, by using first and second glass sheets that have an iron oxide content of 0.005% by weight expressed as Fe.sub.2O.sub.3, the glass sheets have high transparency in the infrared region at wavelengths where the optical sensor 3 operates i.e. between 750 nm and 1650 nm.

[0126] Using a low content of iron oxide provides a convenient way to adjust the amount of ferrous iron in the first and second sheets of glass, although similar effects may be obtained using glass having higher iron content and lower ferrous iron content.

[0127] A further improvement to the transmittance through the laminated glazing 1 is to include an anti-reflection coating on the first major surface 10 of the first sheet of glass 11. Such an anti-reflection coating may be used to increase the transmittance at wavelengths at which the optical sensor 3 is operable. Suitable coatings are known in the art, see for example US 2015/0037570A1.

[0128] Such anti-reflective coatings may cover the entire first major surface 10 of the first sheet of glass 11 or a selected portion thereof. As shown in FIG. 3, an antireflective coating 40 is provided to cover at least a portion of the sheet of PVB 33 to improve transmittance at the wavelength of the sensing beam 15.

[0129] By selection of the interlayer structure 31 the vehicle windscreen 1 may have a second region thereof with a total transmitted solar (TTS %) measured using ISO 13837:2008 Convention A (with outside surface wind velocity v.sub.1 of approximately 4 m/s) of less than 65%, preferably less than 60%, more preferably less than 55%, even more preferably less than 50%. Such a measurement may be made at normal incidence to the first major surface 10 of the first sheet of glass 11 in the same region where the head up display directs light onto the first major surface 10. Such a normal is shown as line 2 in FIG. 3.

[0130] In an alternative embodiment to that shown, the interlayer structure has parallel major surfaces (instead on non-parallel major surfaces 30, 32). The sheet of PVB 33 may be replaced by a sheet of polycarbonate or glass having a higher transmittance at the wavelength of the sensor beam compared to the transmittance of the sheet of PVB 33 at the wavelength of the sensor beam. In such an embodiment the major surface of the polycarbonate sheet or glass sheet are provided with a layer of adhesive such that the polycarbonate sheet or glass sheet can adhere to the first and second glass sheets 11, 21. Furthermore, the adhesive prevents a small gap between the major surfaces of the polycarbonate sheet or glass sheet and the first and second glass sheets. Such a small gap may act as a further interface for the passage of the sensing beam 15, thereby reducing the intensity of the sensing beam.

[0131] In another alternative embodiment, the second sheet of PVB 33 is not located in an opening in the first sheet of PVB 31′, but instead covers the entire upper region of the laminated glazing 1 (similar to how a shade band is configured, except the transmittance at the wavelength of the sensing beam is higher than the transmittance of the lower through-vision region at the wavelength of the sensing beam). In such an embodiment the first and second sheets of PVB are coplanar with edge regions aligned.

[0132] Although in the figures the laminated glazing 1 is shown as being flat, the laminated glazing may be suitably curved by bending the first and second glass sheets. Preferably the laminated glazing is curved in at least one direction. Preferably the radius of curvature in the at least one direction is between 500 mm and 20000 mm, more preferably between 1000 mm and 8000 mm.

[0133] Laminated glass samples were prepared using first and second sheets of 2.25 mm soda-lime-silica glass, each containing less than about 0.01% by weight Fe.sub.2O.sub.3 joined together by a sheet of adhesive interlayer material such as solar-absorbing PVB containing heat-absorbing particles such as CWO or LaB.sub.6. The content of Fe.sub.2O.sub.3 in the glass sheets is sufficiently low to maintain high transmission in the 750 nm-1650 nm region (in particular between 750 nm and 1050 nm and/or between 1500 nm and 1600 nm) through the glass sheets. The content of the heat absorbing particles in the sheet of adhesive interlayer material is such that the laminated sample is provided with suitably low direct solar transmittance whilst having sufficiently high visibly light transmittance in order for the laminated glass to be used as a vehicle windscreen.

[0134] Glass sheets having such a suitably low content of Fe.sub.2O.sub.3 are commercially available from Pilkington Group Limited and are known as Pilkington Optiwhite™. Such glass sheets at a thickness of 2.25 mm were used to prepare the samples in Table 1 below.

[0135] Examples of sheets of such an adhesive interlayer material containing heat absorbing particles are available from Eastman Chemical Company, USA, for example the “Saflex®” type (i.e. S-Series, Q-Series), or from Sekisui Chemical Co., Ltd, Japan, as S-LEC Solar Control Film. Such sheets of adhesive interlayer material may have acoustic performance as desired and may be in wedge form.

[0136] Conventional lamination conditions were used to prepare the laminated glass samples in Table 1. The samples were each made using the same type of solar-absorbing PVB as discussed above except at a different thickness. The thickness used were 0.86 mm, 1.12 mm and 1.29 mm.

[0137] Table 1 shows the various optical properties of the three samples.

[0138] In Table 1, Illuminant A Visible Light Transmittance (%) is measured using Illuminant A according to CIE Publ. 15.2 ANSI Z26.1 in the wavelength range 380-720 nm, inclusive.

[0139] In Table 1, Direct Solar Transmittance (%) is the Direct Solar Transmittance (TDS) according to ISO 13837-2008, Parry Moon Air Mass=1.5 in the wavelength region 300-2500 nm, inclusive.

[0140] In Table 1, Direct Solar Reflectance (%) is the Direct Solar Reflectance (RDS) according to ISO 13837-2008, Parry Moon Air Mass=1.5 in the wavelength region 300-2500 nm, inclusive.

[0141] In Table 1, Total Solar Transmittance (%) is the total solar transmittance (TTS %) measured using ISO 13837-2008 Convention A (with outside surface wind velocity v.sub.1 of approximately 4 m/s).

[0142] In Table 1, IR Solar Transmittance (%) is the IR Solar Transmittance according to ISO 13837-2008, Parry Moon Air Mass=1.5 in the wavelength region 800-2500 nm, inclusive.

[0143] In Table 1, UV Solar Transmittance (%) is the UV Solar Transmittance (TUV) according to ISO 13837-2008, Convention A in the wavelength region 300-400 nm, inclusive.

[0144] In Table 1, % T @ 880 nm is the transmittance through the sample at 880 nm.

[0145] In Table 1, Transmitted Color (L*, a*, b*) is the Transmitted Color according to CIE Publ. 15.2 ASTM Publ. 308, Illuminant D65/10° Observer.

[0146] As the data in Table 1 shows, even the thickest laminated glass sample (Sample 3) has an Illuminant A Visible Light Transmittance (%) greater than 70%.

[0147] The data for the three Samples 1, 2 and 3 are indicative of the properties that may be obtained in a sheet of solar-absorbing PVB having a wedged profile, for example having a thicker upper region having a thickness about 1.29 mm (which may be about 1.3 mm-1.4 mm), a central region having a thickness of about 1.12 mm and a lower region having a thickness of about 0.86 mm (which may be about 0.8 mm) The wedge profile may have a continuous wedge angle to go from the upper region, through the central region to the lower region. Having such a wedge profile is useful in applications where the laminated glazing is to be used as a combiner in a HUD. Typically, in the HUD region the interlayer has a thickness that varies from about 1.15 mm to about 0.95 mm to reduce double image.

[0148] In accordance with the present invention to provide the three samples with a window for a sensor such as a LIDAR, a portion of the solar-absorbing PVB was removed prior to lamination and replaced by a piece of conventional clear PVB, or other material having high transmittance at the wavelength or wavelengths at which the sensor operates. The laminated samples produced had the same properties as in Table 1 except in the region where the solar-absorbing PVB had been removed. In this region, the transmittance at the wavelength or wavelengths at which the sensor is operable was higher because the solar-absorbing PVB was not present.

[0149] The present invention has the advantage that the laminated glazing is provided with two regions having different transmittance to wavelengths at which an optical sensor is operable, thereby improving the performance of the optical sensor. The laminated glazing also may also be useful as a combiner in a head up display in a vehicle.

TABLE-US-00001 TABLE 1 Solar Absorbing Thickness of PVB (with Illuminant first and CWO heat Total A Visible Direct Direct Total IR second sheets absorbing laminated Light Solar Solar Solar Solar UV Solar of Pilkington particles) glass Transmit- Transmit- Reflec- Transmit- Transmit- Transmit- Sample Optiwhite Thickness thickness tance tance tance tance tance tance % T @ No. glass (mm) (mm) (mm) (%) (%) (%) (%) (%) (%) 880 nm L* a* b* 1 2.25 0.86 5.36 80.86 49.26 5.73 61.68 22.89 0.75 29.31 92.47 −3.51 0.52 2 2.25 1.12 5.62 77.62 43.61 5.71 57.59 15.2 0.35 20.45 91.13 −4.49 0.51 3 2.25 1.29 5.79 74.96 39.73 5.4 54.87 10.63 0.19 14.62 90.01 −5.3 0.41