AU628448B2

AU628448B2 - Laminated glass structure

Info

Publication number: AU628448B2
Application number: AU46994/89A
Authority: AU
Inventors: Eiichi Ando; Junichi Ebisawa; Yasuo Hayashi; Akira Hirano; Koichi Osada
Original assignee: Asahi Glass Co Ltd
Current assignee: AGC Inc
Priority date: 1988-12-21
Filing date: 1989-12-20
Publication date: 1992-09-17
Anticipated expiration: 2009-12-20
Also published as: KR900009269A; KR960004373B1; CA2006179A1; AU4699489A

Description

6 2 COMMONWEALTH OF IVUSTP ALIA PATENTS ACT 1952 COMPLETE SPECIFICATION NAME ADDRESS OF APPLICANT: Asahi Glass Company Ltd.

No. 1-2, Marunouchi 2-chome Chiyoda-ku Tokyo Japan NAME(S) OF INVENTOR(S): Eiiclbi ANDO Yasuo HAYASHI Koichi OSADA Akira HIRANO Junichi EBISAWA ADDRESS FOR SERVICE: DAVIES COLLISON Pateit Attorneys 4 4 1 Little Collins Street, Melbourne, 3000.

a 4 COMPLETE SPE iIATION I OR THE INVENTION ENTITLED: Laminated glass structure The following statement is a full description of this invention, including the best method 4 Qof performing it known to Inc/us:- 4 44I 1 Our Ref.: AA-556 (F89-43) la- The present invention relates to a laminated glass structure, more particularly, relates to a laminated glass structure suppressing turbidity arising along with a lapse of time. Laminated glass assemblies have been widely used for windows and sun roofs for automobiles, windows for airplanes, ships and buildings and so on as so-called safety glass because pieces of glass do not scatter at the time of the breakage of a glass sheet and i S 10 the penetration resistance is high. At present, the laminated glass assemblies have been widely used for a S049 wind shield glass for automobiles from the viewpoint of assuring safety. There has been also proposed a type of laminated glass of which the bonding surface side is 15 coated with a transparent conductive film so that the laminated glass has both deogging function and solar SI radiation reflecting function. As the transparent conductive film, a single-layered metal film such as an Au film or an Ag film, a single-layered metal oxide film 20 such as an ITO film or a SnO 2 film or a multi-layered t8 I 81> 8, II

I

2 film wherein an Ag film is interposed between dielectric films of metal oxide such as ITO (Indium-Tin-Oxide), TiOx, SnOx, ZnOx have been used. Since the singlelayered metal film and the single-layered metal oxide film have drawbacks in color tone, durability and electric resistance, the multi-layered film wherein the Ag film is interposed between the metal oxide films of dielectric substances such as ZnO has been widely used.

Figure 3 shows an example of a conventional laminated glass structure in which a transparent conductive film is formed by a multi-layered film having an Ag film between dielectric films in order to give a defogging function and a solar radiation-reflecting function.

The above-mentioned laminated glass has a plastic interlayer 13 made of polyvinyl butyral (PVB) at the bonding surface between a glass sheet 11 arranged at the exterior side of a vehicle and a glass sheet 12 arranged ,at the interior side, and an Ag film :i is interposed o.F between dielectric films 15, 17 such as ZnOx films as a dielectric substance which are arranged between the glass sheet 11 at the exterior side of the vehicle and the plastic interlayer 13, whereby a transparent conductive film 14 consisting of three-layered films is interposed between the glass sheet 11 and the plastic interlayer 13 25 so as to perform the both functions of defogging and solar radiation reflecting. The dielectric films 15, 17 are to increase visible light transmittance by an optical 3interference effect with the metal film 16.

As the plastic interlayer 13, PVB (polyvinyl butyral), EVA (ethylene-vinyl acetate copolymer), urethane or the like may be used. Especially, the PVB has been generally used as laminated glass assemblies for vehicles which require especially safety because it has excellent penetration resistance, and is chemically and optically stable for a long period of time. In this case, a PVB film containing a predetermined amount of moisture is used in order to provide excellent penetration resistance.

In the conventional laminated glass structure as shown in Figure 3, it-is possible to impart a defogging function by heating the transparent conductive film 14 15 arranged at the bonding surface by supplying an electric rt current. Further, since the transparent conductive film 4', 14 possesses a solar radiation reflecting function t,4r 4 itself, a cooling load of air-condition can be reduced, 44.4 so that it effectively functions to save energy.

However, it was found that a phenomenon of turbidity has partially occurred upon expiration of a long period o Oo of time in a case that a laminated glass is formed by 0 0 arranging the above-mentioned transparent conductive film 14 consisting of a multi-layered film including therein the Ag film 16 between the dielectric films 15, 17 made of a metal oxide.

he inventors of this application have found that the t -4turbidity has occurred due to photo-chemical reduction of the layer contacting the interlayer, and the present invention have been achieved on the basis of the abovementioned finding. Namely, the phenomenon of turbidity is avoidable by using a layer having an energy gap of 4 e V (electron volts) or higher as a layer in contact with the interlayer.

According to the present invention, there is provided a laminated glass structure which comprises at least one glass sheet, a plastic layer arranged at the bonding surface of said glass sheet, and a functioning film which comprises single or 15 multiple layers provided between said glass sheet and oi said plastic layer, wherein the functioning film contains a layer having an energy gap of 4 electron volts or 0 6 higher which is in contact with the plastic layer.

0 a0 .A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained by reference to the following detailed p o: description when considered in connection with the accompanying drawings, wherein: SFigures 1 and 2 are respectively enlarged longitudinal cross-sectional view partly omitted of 0 oembodirments of the laminated glass structure according to 0. the present invention; *pppppmoirnt fte aiae gassrutr ccrigt 920616,dbdatL127,46994.res,4 L L g Figure 3 is an enlarged longitudinal cross-sectional view partly omitted of a conventional laminated glass structure; and Figures 4a and 4b are respectively diagrams showing test results by ESCA on surface conditions of a ZnO film and a Ti0 2 film which are respectively in contact with an interlayer before and after the irradiation of ultraviolet rays for 1,000 hours and 100 hours.

Referring to the drawings, wherein the same reference numerals designate the same or corresponding parts, and more particularly to Figure 1 thereof, there is shown an enlarged longitudinal cross-sectional view of 15 an embodiment of the laminated glass structure in the present invention. In Figure 1, a laminated glass has a plurality of, for instance, two glass sheets 1, 2 a plastic interlayer 3 arranged at the bonding surface of the glass sheets 1, 2, and a functioning film 4 20 consisting of one or plural layers arrange at the bonding surface of, for instance, the glass sheet 1 at "'00 the exterior side of a vehicle, wherein the functioning 0 o "00 film 4 comprises a layer having an energy gap of 4 e V or higher as a layer 8 in contact with the plastic interlayer 3.

As the functioning film 4 in the present invention, .various films having various kinds of function can be utilized, such as an optical function wherein light of a predetermined range of wavelength is selectively T T-N11 920616,dbdatl ?7,46994res,5

I

reflected, interrupted or transmitted, an electric function such as electrical heating for melting snow and for defogging, electromagnetic shielding or as an antenna for receiving or radiating electromagnetic waves, a photo-voltaic function such as a solar cell, an electrically light control function such as light control by liquid crystal or an electrochromic material and so on.

Figure 1 shows an example of the functioning film 4 wherein a metal layer 6 made of Ag or Au or the like is sandwiched between dielectric layers 5, 7 such as ZnO, SnO 2 or the like to form a multi-layered film and a layer 8 having an energy gap of 4 e V or higher is formed at the bonding surface of the multi-layered film to an interlayer 3. The functioning film 4 has a solar radiation reflecting function and an electric conductive afunction by the metal such as Ag, Au or the like. The ooa 20 electric layers 5, 7 are to increase the visible transmittance of the functioning film as a whole by an a*a0 optical interference effect with the metal layer 6.

The reason that the layer having an energy gap of 4 e V or higher is used in contact with the interlayer is as follows.

a aThe inventors of this application have found that ZnO, TiO 2 SnOx, ITO and so on, which were used as the dielectric layer 15 as shown in Figure 3, have an energy gap (Eg) of less than 4 e V. The wave length range of 9206 6,dbdat.127,46994.res,6 \r A r DI n/rv

__I

-7solar radiation at the ground level is about 310 nm 2 pm, which corresponds to an amount of energy of about 4 e V 0.06 e V. It was confirmed that when a layer having an energy gap (Eg) of less than 4 e V, for instance, a ZnO layer (Eg 2.47 e V) was in contact with the interlayer 3, it absorbed ultraviolet (UV) light having energy corresponding to the Eg and photo-induced reduction (Zn 2 Zn) took place in the presence of moisture containing in the interlayer.

Figure 4a shows a result of measurement by ESCA which shows the surface condition of the ZnO layer to which the interlayer contacts, before and after the 1,000 So 15 hour irradiation of the ultraviolet light. It shows that there is a reduced product of ZnO after the irradiation oo o .of the UV.

0 e Figure 4b shows a result of measurement by the ESCA of a TiO 2 film (Eg 3.27 e V) (which is conventionally o04 20 used as a dielectric layer instead of the ZnO layer) which is in contact with the interlayer, before and after 100 hour irradiation of the UV light. It is found that there is a reduced product of Ti02 in the same manner as S° o in Figure 4a.

It was also confirmed that a reduction took place on 0 "other type of dielectric layer having the energy gap of less than 4 e V, for instance, CrOx (Eg SnO2, ITO or the like which was used as the dielectric layer 15 as shown in Figure 3.

I920616,dbdat.l ?,46994.res,7 I (i 8 The reduction seems to occur due to a photochemical reaction as follows.

hv ZnO 2e- 2P 2P+ i 02 2H Reaction (1) (Moisture in interlayer) ZnO 2H 2e- Zn H 2 0 If there is a metal layer 16 such as Ag which is easily oxidized as shown, for instance, in Figure 3, oxygen produced by the above-mentioned reaction (1) (ky-er passes through the dielectricA4ilm 15 to reach the metal layer 16, and oxidizes the metal of the metal layer, hence turbidity occurs due to the light scattering by the oxidized metal. For instance, it is considered that Ag is oxidized to form silver oxide, which scatters light, hence turbidity occurs.

Accordingly, when a layer contacting to the interlayer has an energy qap of 4 e V or higher, no reaction occurs, hence the oxidation of the metal located at the opposite side does not take place.

The value of the energy gap in the present invention is obtained as follows. A film having a thickness of about 1 Ipm is formed on quartz glass, and the reflectance and the transmittance are measured to thereby obtain the wavelength dependency of an absorbing coefficient.

From the above-mentioned reason, it is necessary that the layer 8 contacting the interlayer has an energy gap 440 0*44 0 s 0 00 4 I: 00 4 0 40 9 *0 4 0 t 4.- 4 g 4 4 4~ 44~P a';i) /1 a lj 2^ -~r

I--

C.

9 of 4 e V or higher. As examples of such layer 8, there are layers comprising oxide containing at least one member selected from the group consisting of Zr, Ti, Hf, Sn, Ta and In and at least one member selected from the group consisting of B and Si, for example, an oxide containing zirconium and silicon ZrSixOy (when x 2, Eq 5.6 e oxide containing zirconium and boron ZrBxOy (when x 2, Eg 5.2 e SiOx [Eg 8 e oxide containing zirconium, boron, silicon ZrBxSiyOz, or a film made of a material or Ta 2 0 5 (Eg 4.2 e NiO (Eg 4.2 e Ga 2 0 3 (Eg 4.6 e Sb 2 0 3 (Eg 4.1 e MgF 2 (Eg 5.9 e LiF (Eg 11.3 e CaF 2 (Eg 8.3 e V), LaF 3 5.6 e GeF 3 (Eg 4.1 e V) or the like, and laye r aA f-iRo composed essentially of SiO 2 and having additives of Ti, Ta, Hf, Mo, W, Nb, Sn, La, Cr or the like added a«* thereto.

o 4 In SiOx films, the value x is not particularly o limited. However, when x is about 2, a dense amorphous 0000 film can be obtained and i exhibits a good barrier 0 performance to moisture and oxygen from the interlayer.

Accordingly, the SiOxA.fi 4 ms- wherein x is about 2 is Soo. preferably used in particular. When a SiOxn -is o formed from a Si target or a Si0 2 target, it is necessary to use a RF sputtering method because such targets have 4 t no substantial electric conductivity. However, such RF sputtering method is slow in a film-forming speed and t productivity is not good. Further, RF sputtering is not 4, 1 ;V'l jk sr z suitable for forming a uniform layer for a large surface area.

On the other hand, layers composed essentially of an oxide containing at least one member selected from the group consisting of Zr, Ti, Hf, Sn, Ta and In and at least one member selected from the group consisting of B and Si, for example, layers comprising ZrSixOy, ZrBxOy, or ZrSixByOz are advantageous in that these films are amorphous, whereby the grain boundaries disappear and the superior barrier effect to block moisture and oxygen from the interlayer can be obtained, and also advantageous in that a DC sputtering method can be adopted.

oo 15 The composition of ZrBxOy layers is not limited in :oo particular so long as the layers have an energy gap of 4 e V or higher. However, there is a tendency that the resistance to humidity decreases when the atomic ratio x of boron to zirconium is larger than 3, i.e. x 3. On o. 20 the other hand, when x 0.05, the layers are amorphous, whereby the grain boundaries disappear. Accordingly, in o cconsideration of a further improvement of function of the 00 barrier (to block moisture and oxygen from the 0 o interlayer), it is preferable to determine 0.05 5 x 5 3.

On the other hand, when the atomic ratio y of oxygen to zirconium is too large, the layer becomes coarse, i.e. a porous film is produced. When the atomic ratio is too small, the layer becomes metallic and the transmittance is decreases. Accordingly, it is 970616,dbdatl27,46994,res,10 11 preferable to determine a range of 2 y Similarly, the composition of ZrSixOy layers is not in particular limited so long as the layers have an energy gap of 4 e V or higher. In this case, when the atom.i ratio x of silicon to zirconium is in a range of x 0C.O, the layers are amorphous whereby the grain boundaries disappear, denseness is increased, namely, teIre is obtainable a further improvement of a barrier function. In consideration that when x 19, stability of glow discharge in use of the DC sputtering method can be obtained, it is preferable to determine a range of 0.05 5 x 5 19.

15 The atomic ratio y of oxygen to zirconium is preferably in a range of 2.1 s y 40 by the same reason o 0a as the ZrBxOy layers.

The composition of ZrBxSiyOz layers is not limited in particular in the same as mentioned above so long as S. 20 the film have an eiergy gap of 4 e V or higher. However, it is preferable that the atomic ratios x, y and z of 0 00 boron, silicon and oxygen to zirconium are respectively 0 in a range of 0.05 x v 5 19 (wherein x y 3 0 S and x 3y 1 0 are excluded). It is because when 0.05 x y, the film is amorphous so that the grain S. boundaries disappear and the denseness is improved, hence a barrier effect can be further improved, and when x y 19, stable layer forming can be attained by a DC sputtering method. When the layer is considered as a composite 9206 16,dbdat. 127,46994,res, t -12system of Zr0 2

B

2 0 3 and SiO 2

B

2 0 3 is relatively poor in durability to chemicals. Accordingl-, ;Lt is not preferable to employ a composition containing an amount of B 2 0 3 such that ZrO 2 25 mol% and Si0 2 25 mol%, balanced by B 2 0 3 in the layer (namely, when Zr:B:Si (atomic ratio) in a ZrBxSiyOz layer is l:x:y 1/(1 x y) 0.25 and y/(l x y) 0.25, in other words, x y -3 0 and x 3y 1 0) because the durability to chemicals is inferior. The atomic ratio z of oxygen to zirconium is preferably in a range of 2 z 40 for the same reason as the ZrBxOy layer.

It is also preferable to employ the layer composes essentially of SiO 2 and having Ti, Ta, Hf, Mo, W, Nb, Sn, Q0 0 La, Cr or the like added thereto as the layer with the "0 0 energy gap of 4 e V or higher, because such layer is S00 amorphous and can be formed by a DC sputtering method.

0. ;o An amount of the additive element is not limited in 20 particular so long as the layer has an energy gap of 4 e V or higher. However, it is more preferable that the 0 00 0, amount of the additive elements contained in the layer is at least 4 atomic to the total amount of Si and the 0.:0.0 additives because stable Dc sputtering can be conducted by using such an alloy target.

S0 It is also preferable to use the tantalum oxide o*o (Ta 2 0 5 layer which is also amorphous and constitutlts a dense layer, whereby it exhibits a varied to moistue and oxygen from the interlayer. The Ta 2 0 5 film can be formed M S 926i6,dbdal27.6994.rl 2 F -i9- I-aai -13by a DC sputtering method, however it is more or less difficult to get stable discharge with high deposition rate by DC sputtering. Accordingly, the Ta 2 0 5 layer is disadvantageous with this suspect.

NiO layer is also preferable for the layer (Eg 4 e and can be formed by DC sputtering, using Ni target.

However, as Ni is a magnetic material, magnetron DC sputtering, which is the most popular sputtering method which a high film-forming rate, cannot be employed, and is disadvantageous in productivity.

Other materials for the layer (Eg 4 e such as Gag0 3 Sb20 3 MgF 2 LiF, CaF 2 LaF 3 CeF 3 are expensive and are preferable to be formed by vacuum vapour deposition.

Other components may be added to the layer 8 00 contacting to the interlayer in order to adjust an 54 J optical properties, to obtain stability at the time of 20 forming a film, to improve the film-iorming speed and so oi, A desired refractive index can be imparted to a layer made of ZrBxOy, ZrSiOy or ZrBxSiyOz by controlling the film composition because the refractive index of I o, layer is reduced from 2.1 to 1.5 as the amount of B or Si 25 to ZrOx is increased. Similarly, a desired refractive 0 index can be obtained by using a layer made essentially of SiO 2 and having additives; Ti, Ta, Hf or the like added thereto and by controlling the amount of the additives.

It is preferable that the layer 8 with Eg 4 e V 920616,dbdat.l127,46'94,'es ,13 /,IP -14contacting the interlayer has a thickness of 10A or higher. When it is thinner than this, an island-like layer is formed and a unif.rm layer cannot be formed.

Thus, there is produced a portion where no layer 8 is formed.

As the functioning film of the present invention, there are following functioning layers, for instance, although the layers are not limited herein.

As an example of the functioning film having a transparent film including a metal layer, Figure 1 shows a functioning film having the construction of (glass/) dielectric layer 7/metal 6/dielectric layer 5/laye' 8 (Eg 4 e V)(/interl.ayer). Ag, Au, Pd, Cu, Pt or the like or an alloy of these elements, e.g. an Ag-Pd alloy may be used for the metal 6. As the dielectric layers 5, 7, ZnO, TiO 2 SnO 2 Al doped ZnO or SnO 2 in which F or Sb is *doped, or ITO (tin-doped indium oxide) may be used. In the functioning layer having the above-mentioned construction, since the metal layer is a transparent conductive layer which is transparent and has electric .o o4 conductivity, it can be used as an electrically heated Sglass or windshield by attaching an electric heating means such as a bus bar or the like which is formed by printing a conductive material, for example. Since the metal dyer has solar radiation shielding property as well as transparency, it can be used as a heat radiation shielding glass in a case when no electric heating means.

920616,dbda, 127,46994,res,14 r is attached thereof. As described before, the dielectric layers sandwiching the metal layer 6 is to improve the visible transmittance by utilizing the optical interference.

Figure 2 is a longitudinal cross-sectional view showing another embodiment of a laminated glass structure according to the present invention wherein a solar cell thin film is used for a functioning film. Namely, an alkali barrier layer 21 composed of Si0 2 A1 2 0 3 or the like, a first transparent electrode 22 composed of SnO?, ITO or the like, an photo-voltaic layer 23 such as amorphcos silicone layer, and a rear side electrode (a transparent conductive layer) 26 are sequentially formed in this order on a glass sheet 1 at the exterior side of 0 00 a vehicle wherein the layer 8 of Eg 4 e V is interposed Stherein when the glass sheet 1 and a glass sheet 2 at the 0 interior side are laminated with a plastic interlayer 3 therebatween. Thus, a functioning film 4 comprises the multi-layered layers 21 26 and 8.

The transparent conductive film 26 as the rear side electrode may be composed of two or three or more layers such as a metal layer 24 and other layer 25, or may be 25 composed solely of one layer of the metal film 24, or may be composed solely of one layer of transparent conductive material such as ITO, F or Sb doped SnO 2 and so on.

The metal layer 24 may be a layer made of Ag, Au, Pd or Al or an alloy film made of at least two different S920616,dbdat 27,46994.res,15 -16kinds of these materials. Further, said other layer may be a dielectric layer such as ZnO, ZnS, Ti0 2

ITO,

SnO 2 or the like, or a layer composed of a semiconductor material such as Si or the like.

Further, the functioning film 4 may have such construction of (glass/) dielectric layer metal/dielectric layer (Eg 4 e V) (/interlayer) wherein the dielectric layer 5 as shown in Figure 1 is formed by a layer having Eg 4 e V. For instance, it may have the construction of (glass/) ZrSixOy/Ag/ZrSixOy (/interlayer). It is not always necessary to use the layer having Eg S 4 e V for the dielectric layer 15 contacting the glass sheet.

Further, as another example of the construction of the functioning film 4, there are proposed such O" construction of (glass/) absorbing layer/layer 8 (Eg 4 e V) (/interlayer), or (glass/) dielectric layer 20 absorbing layer/dielectric layer/layer 8 (Eg 4 e V) (/interlayer) in order to utilize the solar radiation 0 shielding function of the absorbing layer. As the absorbing layer, a layer composed of a nitride, a boride, a carbide or a mixture thereof may be used. The S 25 dielectric layer is to increase the visible transmittance 0 by optical interference, which may be the same dielectric layer as described with reference to Figure 1. As concrete examples, there are (glass/) TiN/ZrBxOy (/interlayer) or (glass/) TiO 2 /TiN/TiO 2 /ZrBxOy (/interlayer). The absorbing layer may increase the visible transmittance by 920616,dbdal 27,46994.rcs,16 17oxidization (for instance, TiN is partially changed to Ti02). However, in accordance with the present invention, the oxidization of such absorbing layer can be avoided.

As another example of the functioning film 4 wherein a transparent conductive film without any metal layer is used, there are (glass/) transparent conductive film/layer 8 (Eg 4) (/interlayer) or (glass/) alkali barrier layer/transparent conductive film/film 8 (Eg 1 4 e V) (/interlayer). As the transparent conductive film there are ITO (tin-doped indium oxide), F- or Sb-doped SnO 2 or Al-doped ZnO. As the alkali barrier layer, there are SiO 2 or A120 3 The alkali barrier layer is to prevent the diffusion of alkali ions from glass into the transparent conductive film to thereby increase the oo:4 resistance of the conductive film. A laminated glass in which such transparent conductive film is formed can be used as electromagnetic shielding glass or a glass antenna.

In the laminated glass structure having the abovementioned films, another kind of film can be interposed between adjacent films or between a film and a glass 25 sheet in order to improve bonding property and to adjust Soptical properties.

As a film-forming method for the functioning film 4, a spraying method, a vacuum vapour deposition method, a DC sputtering method, or a chemical vapour deposition method may be used. However, in view of the productivity and 920616,dbdatl27,46994.res,17 I 18 the film thickness uniformity for large area coating, it is preferred to form films by the DC sputtering method.

In preparing a laminated glass having such functioning film and having a curved surface, glass sheets may be shaped to have a desired form before the films are formed on either of the glass sheets, or the films may be previously formed on a glass sheet and then, the glass sheets may be shaped to have a desired form.

In the present invention, sodalime silicate glass sheets, aluminosilicate glas sLheets, borosilicate glass sheets, lithium aluminosilicate glass sheets or the like may be used for the glass sheets 1, 2 although the present invention is -not limited thereto. It is especially preferable to use the sodalimesilicate glass sheets because they are available at a low cost.

Further, a solar absorbing glass sheet having Ni, Cr, Co, i' Fe, Se or the like as additives may be used.

As the plastic interlayer used for bonding the 0o glass sheets 1, 2, PVB (polyvinyl butyral), EVA 20 (ethylene-vinyl acetate copolymer), urethane or the like t may be used. However, when a laminated glass for a vehicle is to be prepared, it is preferred to use PVB having excellent resistance to penetration and It durability.

Description has been made as to laminated glass structures wherein two glass sheets are used. However, the present invention may also be applied to a laminated tit <4 1 04 i 0 -19glass structure wherein three or more glass sheets are used. In a case that such a laminated glass structure is used for a vehicle, it is preferable that the functioning film 4 is formed at the bonding surface of the glass sheet located at the outermost side.

Since the layer 8 having Eg 4 e V is formed on the contacting surface to the interlayer 3 in the laminated glass having the above-mentioned construction of the present invention, turbidity can be effectively suppressed in such a case that a material which causes oi 0 0 the turbidity through oxidation is contained in the functioning layer.

In a case that the functioning film includes a material which invites increase of visible transmittance by oxidation, such as an absorbing layer, such increase of transmittance can be prevented according to the present invention.

S 20 As an advantage other than the above-mentioned advantages of the present invention, it was found that the bonding strength between the functioning film 4 and the interlayer 3 did not change for a long period of time because the laminated glass structure of the present 25 invention has such construction that the layer 8 having 0 0 Eg 4 e V is in contact with the interlayer. The reason seems to be as follows. Let's take ZnO having Eg 4 e V as an example. Hydrogen atoms at the surface of the interlayer and oxygen atoms in ZnO are bonded in a Z A920616,dbdatl27,46994.res,19 relation of (interlayer) with a hydrogen bonding strength between ZnO and the interlayer such as a PVB film. However, when the Zn-O bond is broken by the reduction of ZnO due to moisture and ultraviolet radiation as in the above-mentioned reaction, there is a possibility that the above-mentioned hydrogen bond does not contribute to the bonding strength to the interlayer.

Let's take another example of ITO (tin-doped indium oxide). In this case, it is considered that a hydrogen bond is formed in a relation of (interlayer), which is broken when indium is reduced and In-O bond is separated, whereby the hydrogen bond does not contribute a o Q 15 to the bonding strength.

The above-mentioned explanation can be applied to a 0::o case of using SnO 2 or other materials with Eg 4 e V.

In the present invention, however, since a layer having an energy gap of Eg 4 e V is used as the layer 20 contacting with the interlayer, such layer is not reduced °0 by the ultraviolet light and does not cause any change.

0 Accordingly, it is considered that the bonding strength can be maintained for a long period of time.

The laminated structure of the present invention can S 25 be applied to a bi-layer type laminated structure of a glass sheet and a plastic layer, namely, glass/functioning film/plastic layer, wherein the functioning film has a layer (Eg 4 e V) in contact with the plastic layer. The plastic layer may be a 9206 16,dbdaLj27,46994.res,20 -21 single layered plastic made of the same material as mentioned for above interlayer, or may be a multi-layered plastic, for example, (glass/functioning layer/) energy absorbing layer/self-healing layer. Said energy absorbing layer and self-healing layer may be made of various kinds of urethane, for example. Said energy absorbing layer is employed to absorb the shock in case of an accident, and it is preferable to contain certain amount of moisture in order to provide good penetration resistance. Said self-healing layer may be replaced by a plastic layer, such as a polyethlene terephthalate layer, or a nylon layer.

Now, the present invention will be described in detail with reference to Examples and Comparative Examples.

EXAMPLES

Various types of functioning film were formed on S 20 glass sheets by a sputtering method, laminated glass .°°00o structures were prepared by bonding other glass sheets Swith PVB films therebetween. Thus, prepared laminated glass structures were subjected to radiation of ultraviolet light for 100 hours. Table 1 shows film 0 25 structures of the functioning film of the laminated glass and the appearance after the radiation.

S920616,dbdat.27,46994.res,21 (0 ft Al -e 000 44 V. 4 *0 0 4* 44 44 44 44 4, 4444 44 444 0 44 *44 44 9 44 44 0 44 C 9 44 44 9' 044 9 440 44 44 44 44 44 44 0 044 44 Table 1 Sample Film structure (Numerical values in Table show Eg Appearance No Ifilm thickness after UV radiation for 100 hrs.

Example 1l PVB/Zr'BxOy/ZnO/Ag /ZnO/Glass x =2 5.24 No change 450 100 450 y 2 PVB/ZrSixoy/ZnQ/Ag /ZnO/Glass x 2 5.59 1 450 100 450 y =6 j3 PVB/ZrBxSiyOz/ZnO/Ag /ZnO,/Glass x 1 5.30 1 45(' 100 450 y =1 z 4 PVB/Ta 2

O

5 ,/ZnO/Ag /ZnO/Glass 4.2 1 PVB/SiO 2 /ZnO/Ag /ZnO/Glass 8 450 100 450 6 PVB/SiO 2 :Ti/Zno/Ag /a-Si/Sn0 2 /SiO 2 /Glass 7 400 200 4000 6000 800 7 PVB/ZrBxOy/Ag /a-Si/SnQ 2 /Si0 2 /Glass x 2 5.24 400 200 4000 6000 800 y 8 PVB/ZrSix~y/TiN/Glass x =2 5.59 1 20 y 6 9 PVB/ZrBxOy/CrNx/Glass x 2 5.24 20 y PVB/ZrBxSiyOz/TiO 2 /TiN/TiO 2 /Glass X 1 5.30 400 80 400 y =l 1 z 55 0 S a

S

S a a S Table 1 -(co-nt-iued) Film structure (Numerical values in Table show film thickness A) Eg (eV)* Appearance after UV radiation for 100 hrs.

N

I.-

Cowrparati ye Example PVB/ZnO/Ag /a-Si/SnO 2 /Si0 2 /Glass 400 200 4000 6000 800 PVB/SnO 2 /Ag /SnO 2 /Glass 450 100 450 PVB/TiO 2 /Z no/Ag /ZnO/Glass 450 100 450 PVB/CrOx/ZnO/Ag /ZnO/Glass 450 100 450 2.47 3.33 3 .27 <1 Turbid

T

I d I A mark in Table 1 indicates energy gap (Eg) of the layer contacting with PVB.

As is clear from Table 1, no change of the appearance was found in the case that the energy gap Eg of the layer contacting with the interlayer is 4 e V or higher. On the other hand, turbidity was found in the case that the layer having an energy gap in a relation of Eg 4 e V is in contact with the interlayer.

Further, in Examples 1 10 (sample numbers 1 there was no substantial change in the initial bonding astrength even after ultraviolet light was irradiated for 1,000 hours. On the other hand, a slight change was found ir' bonding strength in Comparative Examples 11 14 a a (samplc numbers 11 14) after 1,000 hours radiation of ultraviolet light.

As described above, in the laminated glass structure of the present invention in which a functioning film is I Ia 20 formed between an interlayer and a glass sheet, a layer .1 having Eg 4 4 e V is used for the layer contacting with "6 the interlayer. Accordingly, such layer can not be reduced by ultraviolet light and moisture containing in the interlayer. Further, turbidity and an increase in 25 transmittance can be avoided even in a case that the functioning film includes metal which causes turbidity due to oxidation and an absorbing layer which causes an increase of transmittance. Accordingly, a stable laminated glass structure without any change in \A S] 920616,dbdat.127,4694,reS,24 appearance for a long period of time can be provided.

Further, in the laminated glass structure of the present invention, there is no change of a bonding strength for a long period of time and it has a high reliability.

The laminated glass structure of the present invention realizes a laminated glass having a functioning layer having various function and reliable for a long period of time. Further, it can be preferably used not only for buildings but also for vehicles to which higher reliability is required.

9 O Obv iouy, ni-m-n'e-reus- -fd-i-f at-,-l o and vari at-fts-e---rro. the present invention-are possible i:i light ofe above teachings. It is therefore to be erstood that within 15 the scope of the ap claims, the invention may be practic herwise than as specifically described rin. OO 0 0 9 o 4* L 0 9 I t 9 4f j V 4;

Claims

1. A laminated glass structure which comprises at least one glass sheet, a plastic layer arranged at the bonding surfacre of said glass sheet, and a functioning film which comprises single or multiple layers provided Letween said glass sheet and said plastic layer, wherein the functioning film contains a layer having an energy gap of 4 electron volts or higher which is in contact with the plastic layer.

2. The laminated glass structure according to Claim 1, wherein the functioning film comprises a single or multiple layered transparent conducti'e film including a metal layer between the layer having an energy gap of 4 0.0 electron volts or higher and the glass sheet.

3. The lawinated glass structure according to Claim 1, 00 20 wherein the functioning film comprises a single or o000 o 0 multiple layered heat radiation shielding film including 0 0: a metal le-er between the layer having an energy gap of 4 electron volts or higher and the glass sheet.

4. The laminated glass structure according to Claim 2, wherein the transparent conductive film further comprises a first dielectric layer between the metal layer and the layer having an energy gap of 4 electron volts or higher, and a second dielectric layer between the metal layer and the glaso sheet.

The lavinated glass structure Ccnording to Claim 4, wherein the first and second dielectric layors are ZnO and the metal layer is Ag. 920616,dbdat.127,46994.res,26 I__ i~*i -27-

6. The laminated glass structure according to Claim 4, wherein the first and second dielectric layers are SnO 2 and the metal layer is Ag.

7. The laminated glass structure according to Claim 1, wherein the functioning film comprises a thin solar cell film including a first transparent electrode, a photovoltaic semiconductor layer and a second transparent electrode, said second transparent electrode having a metal layer between the layer having an energy gap of 4 electron volts or higher and the glass sheet.

8. The laminated glass structure according to Claim 1, Swherein the functioning film further comprises a solar radiation shielding layer between the layer having an energy gap of 4 electron volts or higher and the glass sheet.

9. The laminated glass structure according to Claim 8, S 20 wherein the solar radiation shielding layer is composed essentially of at least one member selected fron, thv group consisting of nitride, boride and carbide.

The laminated glass structure according to Claim 1, 25 wherein the functioning film further comprises a transparent conductive non-metal film.

11. The laminated glass structure according to any one of Claims 1 to 8, wherein ths layer having an energy gap of 4 electron volts or higher is amorphous.

12. The laminated glass structure according to Claim 1, wherein the layer having an energy gap of 4 electron volts or higher is essentially composed of one member selected from the group consisting of SiCG, Ta 2 05, NiO, Ga 2 0 3 Sb 2 0 3 MgF 2 LiF, CaF 2 LaF 3 and CeF 3 920616,dbdatI27,46994.res,27 28

13. The laminated glass structure according to Claim 1, wherein the layer having an energy gap of 4 electron volts or higher is essentially composed of SiO 2 and has at least one additive selected from the group consisting of Ti, Ta, Hf, Mo, W, Nb, Sn, La and Cr.

14. The laminated glass structure according to any one of Claims 8 to 10, wherein the layer having an energy gap of 4 electron volts or higher is essentially composed of an oxide containing at least one first member selected from the group consisting of Ti, Hf, Sn, Ta and In and at least one second member selected from the group consisting of B and Si. o 00 o "o 15

15. The laminated glass structure according to any one of Claims 8 to 10, wherein the layer having an energy gap of 4 eleotron volts or higher is essentially composed of an oxide containing Zr and B(ZrBxOy), wherein the atomic ratio x of B to Zr is 0,05 5 x 3, and the atomic ratio y of O to Zr is 2 y

16. The laminated glass structure according to any one of Claims 8 to 10, wherein the layer having an energy gap .of 4 electron volts or higher is essentially composed of an oxide containing Zr and Si (ZrSixOy), wherein the atomic ratio x of Si to Zr is 0.05 5 x 5 19, and the atomic ratio y of 0 to Zr is 2.1 y

17. The laminated glass structure according to any one of Claims 8 to 10, wherein the layer having an energy gap of 4 electron volts or higher is essentially composed of an oxide containing Zr, B and Si (ZrBxSi yOZ), wherein the atomic ratio x of B to Zr, the atomic ratio y of Si to Zr, and the atomic ratio Z of 0 to Zr are 0.05 x y 19 (except x y 3 0 and x 3y 1 0) and 2 z 920616,dbda 27,46994,res,28 I L~ L-l JC I -29-

18. The laminated glass structure according to Claim 1 wherein the layer having an energy gap of 4 electron volts or higher has a thickness of 10 A or more.

19. The laminated glass structure according to any one of Claims 1 to 12, wherein the plastic layer comprises polyvinyl butyral. The laminated glass structure substantially as hereinbefore described with reference to the drawings (excluding Figure 3) and/or Examples (excluding the Comparative Examples). DATED this 13th day of July, 1992 Asahi Glass Company Ltd. By Its Patent Attorneys DAVIES COLLISON CAVE n~oo iano oiil, o o a a R O a i) O a a OB UO no o a an a o ri J ,o a a o us u a u~ ~~J a Itr o a v o n o a ilo a D a B a 9207 l0,dbdat. 127,46994,res,29