DE1901154A1 - Translucent window material - Google Patents

Description

DA-3150

B ee ο h r β i ta u η g to the patent application

of the company

POLAROID CORPORATION 730, Main Street Cambridge, Cheese », USA

concerning

Translucent? Eneter material priority? tu January Λ968, Hr, 697 U3,

The invention relates to the use of τοη light polarizers in conjunction with load-bearing or tensioned synthetic plastics materials in a ruaam set penstructure. In particular, the invention relates to the use of high-wave coatings "to separate out the interference spectra resulting from the polariscopic effect that is generated" when a strained translucent material is viewed between two light polarizers.

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It is a primary object of the present invention to eliminate the undesirable interferences associated with the polaj? Iekopis (? Hen I effect) when viewing a stretched translucent material between two sources of polarized Iiioht , "■ ■" ■ ·.. ·; ■ '--ν.'V.:-.'■-■■■■"; ■ '.' ■ · - -. ■, ■ '.

Another object of the invention is ea, a compound To indicate penöter construction »which is particularly suitable for pressurized plug cabins and which contains a stretched transparent part and a light polarizer », whereby light passing through is free is of chromatic aberration, the occurs together with the polariscopic effect.

Another object of the invention is to produce synthetic Specify existing plastic shaft linings or plates that lead to a delay or lag of at least 7 wavelengths are capable.

Another object of the invention is to provide windows with to indicate variable density, which contain several light-polarizing elements as well as means assigned to them, to control the light let through.

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Other objects of the invention are partly self-evident, some of which can be found in the following statements.

To better understand the essence and nature of the Invention is referred to the following detailed description, together with the accompanying drawings.

Flg. 1 is a graph plotting wavelengths versus the relative transmittance of white light passing through the various delay zones * where ^ _ΛΛχ and T ₁ ^ _{n are} the maximum and minimum optical transmittance for a given system βInd.

Pig. 2 and 5 are sectional side views of FIG Äueanimengeaetaten? Ensterkonatruktiohen in the area of present invention.

Fig * 4. 5 and 6 are sectional side views of window constructions, the sub-combinations in Represent the scope of the present invention.

Flg. Fig. 7 is a sectional side view of a window part on which a high undulating laminate is formed Covering "is located.

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Ee is very often called for, light that enters a room or a moving vehicle enters «by using to attenuate light polarizing material. Basically, it may be desirable, and in fact, it is well known to employ a technique in which one light polarizer is rotated relative to another in order to If you wish, a complete service every week of any incident light. to reach. The need for such a damping is particularly important in the case of mobile drivers' eyes and in particular in aircraft, which often receive direct radiation without the Advantage of natural damping, e.g. exposed to cloud formation

Sunlight is by its nature rather highly polarized, ie there is a preferential direction for the oscillations of the light waves due to partial ohena scattering and the like, which leads to a more or less oriented waveform in contrast to the random waveform. This effect can easily be demonstrated by rotating a polarizer held against the light entering from the sky and by voting the differences in the intensity of the light passing through. If the absorption axis of the polarizer is parallel to the primary plane of oscillation of the incident light,

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If the polarizer is aligned with the axis of passage of the polarizer, a partial cutout takes place to a greater extent than this would be achieved.

A high degree of bridge * and security for the inside of a modern aircraft. »The outer penster construction piles are made of a very high tension synthetic plastic material, usually polymethyl acrylate (Plexiglas, Lucite)» but can also polycarbonates such as Lexan, the condensation products from the reaction of bisphenol A with phosgene and Bi ** ethylene glycol to allyl carbonate, commercially available from Pittsburg Plate Glass Company under the trade designation CR-39 » or use other suitable clear materials. As an emergency or safety measure, a «wide synthetic plastic window construction material, which ever contains a tensioned or non-tensioned material, on the inside of the outer tensioned (part appropriate. If a light polarizer is attached to the inside of the clamped part or parts is brought, one can notice a polariscopic effect. This means that this is outside the window incident polarized light and the polarizer attached to the inside of the Penster form an analyzer

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The one who depicts the tension roughness of the synthetic plastic window parts in a strong and colorful way.The maximum effect occurs when the polarizer absorption axis is at an angle of 90 ° to the axis of the incident polarized light * This polar copy phenomenon is right from an aesthetic point of view undesirable and often frightening the passengers of the aircraft unnecessarily, auraal the coughs change with pressure fluctuations.

Those on airplane windows with a light polarizing probe Element au observing stress patterns are due to the birefringence occurring in the stressed material occurs. In polymethylacrylate and similar windows, the maximum retardation produced by this birefringence is up to about 3 wavelengths, which is a powerful ^ colored area results.

The retardation can be viewed as the product of birefringence and the thickness of a given material. Accordingly, if the two refractive indices of a given birefringent material are given as η and n ,, the birefringence as (nn ^) = Δη and the thickness of the material as t, the delay is represented by the equation:

r-

BATH 00881 Q / 038 t

Since the thickness range and the birefringence of the part used for the window according to the invention are such that a delay in the order of magnitude of approximately 3 wavelengths is achieved, a method can be found which causes a depolarization and thus an essentially white Creates light. ■

At this point it can be "waking up" to briefly mention the theory with which the various ohromatiaohen Effects are generated * that are obtained with stretched synthetic Kuneteto material of the type that is shown here in a polarcopy arrangement is used »

For example, assuming that an at one point in this material the stress causes its birefringence, which is roughly its delay or shift by 1/4 wavelength compared to 575 mu Causes light, which is about in the middle of the visible spectrum, one gets a delay of 144 mu. According to Fig. 2, the polarizer attached to the inside is arranged in such a way that it provides maximum extinction of the incident sky light, i.e. that the absorption axis of the Folarisatore is parallel to the primary plane of vibration of the incident light

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lies. It can be seen, as shown in FIG. 1, that for the mean Lloht spectrum an effect on the transmittance is achieved with a delay of a quarter wavelength, this means for light of wavelength 400 τψ 144/400 or approximately a third of a wavelength delay ; for light with a wavelength of 750 mu, this means about a fifth of a wavelength delay. It is evident that the resulting light is colored faintly blue. If a wavelength delay of approximately three-quarter waves is produced in 575% of light, it can be seen from FIG. 1 that the resulting light should be approximately amber. A delay of half a wavelength compared to 575 au light produces a greenish-yellow light. Furthermore, the effect of 1.25 and 3.0 wavelengths delay at 575 .mu.m light on light that could be incident on the system according to the invention is indicated in the graph. For demands of up to about 3.5 wavelengths of delay, very strong simple colors become progressively visible, beyond 3 * 5 wavelengths the colors are so fluid that they cannot be individually distinguished from one another and appear as less colorful oeniseh or as white light. These phenomena can be graphically represented as curves that have many Ma xi "» * and Hiniaa.

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It is known that a light-polarizing toilet does not causes substantial extinction of polarized light when its absorption surface is parallel to the plane of vibration of a birefringent material, the »wipe the polarizer and the polarizing Light is arranged because the double refracting Kate * rial changes the linearity of the polarizing light waves passing through and causes the Boiesion waves, which are circular or elliptical »If a stress axis is at an angle of 45 ° ssu of the permeability- or absorption axis of the crossed folarizers is located, it has also been found that a maximum intensity of the interference spectrum is reached. If the stress axis corresponds to the permeability or the absorption axis of the polarizer coincides, no effect can be observed. The resulting pattern, which is therefore presented to a viewer, appears as 4 clear circular arcs with a maximum Intensity at the center of each sector and with a minimum intensity along the polarizer axes

If now there is a wave coating or a wave plate with a delay of about 10 to 15 wavelengths in a combination? .Us a tensioned window and light polarizer, is used on the outside of the polarizer, so

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has been shown that an effective depolarization of incident light, i.e. that the polariscopic effect is avoided of the window material is additive, it is easy to see that a shaft coating has a delay of about 4 wavelengths is sufficient to produce essentially white light. However, if the wavelengths of the delay possible due to the wave coating are subtractive in relation to that of the stretched window, about 7 or 8 wavelengths of delay would be required to be required. In order to achieve maximum effectiveness and to take the delay into account which could be imparted to the system by inadequate laminates, the use of retarders must be used in the On the order of 10-15 wavelengths delay as Ideally to be considered · For practical purposes, however, any material that has about 7 or more waves can be used long delays can be used, e.g. oriented polyvinyl alcohol, various oriented Polyester and the like. It has now come as a surprise shown that the best results are obtained when polyethylene terephthalate (Mylar, Melinex) is used, that has been uniaxially oriented. With such a material, delays and up to 20 wavelengths can be achieved

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maybe even more can be achieved. Bich has an additional advantage with uniaxially oriented polyethyleneterephthalate compared to other materials, since the optical axes of this material are not visible to the observer, regardless of the position he is in! because the critical angle is an inner or acute angle. There is therefore no possibility for the viewer to look at an optical axis of the material and only see a black surface that is surrounded by a colored environment.

In all execution forms of the invention, the greatest effectiveness is achieved when the plane of the optical axes of the shaft covering is located at an angle of 45 ° on the axes of the rigid light-polarizing elements. When the plane of the optical axes of the wave coating reaches an axis of the light polarizing element , effectiveness is lost until the foliar satorachae and the plane of the wave coating axis coincide, a point at which the wave coating can no longer produce the intended results .

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Any suitable material which will produce the desired light-polarizing effect can be used for the purpose of the present invention can be used. However, it has been shown that polymeric, light-polarizing layered material easiest this funk * tion can take over. The preferred material is a clear layer of polyvinyl alcohol, which is essential oriented molecules of dehydrated It contains vinyl alcohol and its light-polarizing properties essentially differ from those of dehydration Molecules. The manufacture and use of such layered material is described in US Pat U.S. Patents 2,173,304, 2,255,940, 2,306,108, 2,397,231, 2,445,555, 2,453,186, and 2,674,159.

As a general rule, it can be assumed that neither the polarizer nor the wave coating are structurally so rigid that they can be used as such. Therefore, in most of the preferred embodiments According to the present invention, both the polarator and the wave coating become one rigid synthetic plastic material, e.g. on polymethyl methacryl & t before the struc- ture is assembled. In the case of the V / ellenplatte it has been shown that that it is preferable to use them with the

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Eetite light-polarizing blemishes "u!" Be it should be pointed out, however, that the wave plate may also be placed on a stretched or non-stretched synthetic plastic nucieuefenaterbeatandteil can be laainiert. Fall on a clamped part be laminated »oll, that in a standard execution represents the outermost & window component, ee is preferably attached to the inside of the cabin, like this is indicated in Pig, 4. Technically speaking, that is Wave plate for the purpose intended for Bie workable if they are outermost on the outside dee is laminated. Passing constant auesetaen of the elements speaks against such a thing

aq £ inner or · ^^ nkaiiit »4 + ab>» Minit «4> a ν« »«! ■ - t

the wave plate either on the inside or on the outside

this window component attached or laminated j

be like this in the pig. 5 and 6 is indicated. The J

main criteria for the mediation of the pacification |

The position of the wave plate is that it is awisohen; the sources of polarized light, i.e. the sky

and the light-polarizing element must be arranged · i

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Fig. 2 describes an embodiment according to the invention, in which a V / ellenplatte on the outside of a borrowed

- · ■ ■; ■■ - ■. ■: ■ ■ j.-

polarizing element and on the inside of a stretched penate part in a plug stuff window is used ^. . · '

• ♦ ■ · ι

Pig. 3, which is described in more detail below, leigt a preferred Ausihrungsforra according to the invention, with a first light polarizing material between

t & etiachee Kunit ^ tofiMrägeriJiiiteirlai eötfa ^ te »* where a wave plate on the outside of the Bueamraengeset «- th light polarizing unit is laminated. On the Inside this! Dent is a second light polarizer between clear synthetic plastic embossed construction material laminated, whereby the assembled rope can be rotated so that the axes of the second Lishtpolarisatore at different angles the most light polarizer can be brought to thereby to achieve changing degrees of exposure or changing transparency of incident light * Everyone for laminating the wave plate polarizer substrate Suitable adhesive can be used, as long as the adhesive has the transmittance of light does not prevent. Adhesives that can be used for the purpose of Suitable invention, generally contain low molecular weight polyesters in situ with a suitable crosslinking agent networked ^ are examples of such materials are Adcote 1069 from Morton Chemical Company; it is a low molecular weight polyethylene terephthalate, probably with terminal hydroxyl

- »he

groups, in connection with a polyisocyanate agent. Other polyesters suitable for this purpose are the duPont adhesive Br 46960 and the Atlonal 8 taroh adhesives Kr. 76-2575. 50-9057 and 30-9066. These adhesives are typically polyesters which are used in conjunction with a suitable crosslinking agent such as a polyisocyanate. The adhesives can be used alone or in conjunction with other adhesives. The most preferred embodiment of the present invention makes use of a uniaxially oriented polyethylene terephthalate corrugated plate which is bonded directly to a polymethyl methacrylate carrier part Polyisocyanate crosslinking agent. A thin layer of a cellulose acetate butyrate from solution is applied over this coating. This is followed by a thin layer of Adcote 1069 »see above, with a polyisocyanate crosslinking agent. This provided with upper trains structure is then laminated using conventional Druokwalzenteehnik with the polymethyl methacrylate-support part by using an adhesive consisting of about 4 # nitrocellulose having a viscosity of about 600-1000 seconds ^"!, Dissolved in methyl methacrylate and comparable

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applies with a diisopropyl percarbonate catalyst, present in an amount of about 1 wt.

In order to achieve optimal properties in terms of shrinkage and to achieve cracking of the light-polarizing material, it has been found to be desirable Laminating polarizer between layers of cellulose acetate butyrate or similar materials (see U.S. Patent 2,674,159). Laminating the cellulose acetate butyrate layers with the light-polarizing material can be done, for example, by clicking on the Cellulose acetate butyrate material is a suitable compound as a coating, e.g. cellulose nitrate, whereupon this coated material with the polyvinyl alcohol light polarizing layer using the known pressure roller technology with a typical adhesive for such Material is laminated, e.g. with a 2 # polyvinyl alcohol solution. However, lamination can also be used by converting the surface of the cellulose acetate butyrate into cellulose, the surface coated with polyvinyl alcohol and the coated cellulose acetate butyrate with the light-polarizing Laminated material under pressure.

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The present invention can be further referenced Fig. 3 will be further described. She provides one preferred embodiment, in which a tensioned Window portion about 1.27 cm (0.5 in) thick on the outside of a tensioned or non-tensioned security window part of about 0.6? up to 1.27 cm (0.25-0.5 inch thick), which in turn is placed outside a rigid light polarizer ! Ceils, which contains a laminate. This laminate consists of the outside in the following order made of a wave plate with a thickness of about 38.1 to 125 microns (1.5-5 mils), and preferably 76.2 microns (3 mils); a clear synthetic Plastic backing member approximately 762 to 3175 microns (30-125 mils) thick and preferably about 152.6 microns (60 mils); a clear synthetic plastic protective material layer having a thickness of about 101.6 to 762 microns (4 30 mils), preferably about 125 microns (5 mils); one The light po3.arating part, as described above, having a thickness of about 19.05 to 38.1 microns (0.75-1.5 mils), and preferably about 19.05 microns (about 0,? 5 mil) j and made of a second synthetic plastic layer on a second transparent carrier layer the same dimension as the first carrier layer.

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Located on the inside of the part just described a rotatable part, which has a synthetic plastic carrier material, einaeyntheche Plastic protective layer, a light polarizing material, a second synthetic plastic protective layer and a second transparent support part. All these

■ Layers have the same dimensions as at

specified in the item above. With the preferred Embodiment contain the synthetic protective layers Cellulose acetate butyrate. The corresponding Components of the assembled window structure can be held together by suitable fasteners , including an opening matching the above

■ described translucent means transversely (i.e. in {of the opening), e.g. a cylindrical part j with suitable flat feet holding the elements.

4, 5 and 6 show sub-combinations of other forms of implementation according to the invention and give schematically the various positions which the wave plate in the device claimed here ' can take. The bonding methods and the particular adhesives used to bond the wave plate with a certain window part are identical to the ones above when laminating the wave plate with a Support part have been described.

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In the case of the invention. Device with alternating At will, density can have a second rigid, light-polarizing element with its axes parallel to attached to the first light polarizing element. By rotating the rotatable light polarizer Element one then obtains a more complete extinction of the incident light, whereby the efficiency of the system can be further improved Embodiment, it is preferable to place the rotatable element between the rigid light-polarizing elements *

The expressions "outside" or "on the outside" used in the present description are intended to denote the side from which the light can enter the device according to the invention, while "inneii" baw. "an der Vn.ue: 's ^ r. *: e" denotes that Sei-ce through which' the hinduro'igclasseno light emerges from the device again:

The orfir-.d \; r.jrg-? -Made device can be used not only in 3? Lug bodies, but also in railway wagons, ships and the like.

Patent entitlement

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Claims (10)

Claims 1. Translucent window that is fixed in an opening and contains several translucent parts, characterized in that in the window opening towards the outside there is a first transparent stretched plastic part, a wave plate with a delay of at least 4 wavelengths and a rigid light-polarizing one Part is located. 2. Window material naoh spoke 1, characterized in that the wave plate has a delay by at least 7 wavelengths. 3. Window material according to claim 1 or 2, characterized in that the wave plate is uniaxial contains oriented polyethylene terephthalate. 4. Window material according to Artspruch 1 to 3, characterized in that the wave plate on the Inside of the tensioned plastic part is laminated. - 20 - BATH 009810/0389 5. Window material according to claim. 1 to 4, characterized in that there is also a two * tee contains clear synthetic plastic rope on the inside of the first component and on the outside of the light-polarizing parts. 6. Window material according to claim 5, characterized in that the wave plate with the second synthetic plastic part is laminated. 7. Window material according to claims 1 to 6, characterized in that the wave plate and the light-polarizing part, a single assembly Form structure that hex from the outside? seen the wave plate, a clear synthetic one Plastic carrier part · a first transparent one Protective layer for the light-polarizing rope, the light-polarizing rope itself and a «wide, thermoset protective layer for the light-polarizing part exhibit. 8. Window material according to claim 7, characterized in that the composite structure is additionally a transparent synthetic Kunstetoff- - 21 - BATH ORIGINAL 009810/0389 ^: -.te. ^x : i * * a · 3 * j »tit • · · f »i ι It ♦ * * * * ti Support part on the inside of the outer transparent protective layer for the light-polarizing material and attached to this material contains 9. window material according to claim 1 to 8, characterized in that a rotatable, light-polarizing Part on the inside of the rigid, light-polarizing part eats. 10. Window material according to claim 1 to 9 »characterized by g e, that. the wave plate has a thickness of 38.1 to 125 microns « BATH ORIGINAL 00981Q / Q389 Blank page