NO135295B - - Google Patents

Description

The present invention relates to a sunglass lens for sunglasses of a type to be worn by a person, where the lens is arc-shaped around the wearer's face and with a lamellar structure designed to shield light from selected directions. Furthermore, the invention relates to a method for production

of the sunglass lens, using a preformed multi-layer lamellated, thermoplastic substrate which includes opaque lamellae or the like. arranged within the substrate and normally on the plane of the substrate.

In the past, different types of lamella sunglasses have been attempted where the lamellas in the lenses are arranged in a horizontal plane (when the wearer is standing). Sunglasses of this type have generally been too effective in masking away the sun from above and cutting light from below. Consequently, such sunglasses have been fraught with problems of the type where a driver operating a motor vehicle and wearing such sunglasses would have difficulty looking down to check the speedometer or other gauges which are normally located below the line of sight. Similarly, a cross-country skier would have difficulty seeing the tips of his skis when looking forward. The ski tips are completely masked, as the angle of view in a vertical plane is quite narrow in these normal types of lamella sunglasses.

Other attempts have been made to provide a suitable sunglass which will mask out direct rays from the sun and the cutting light of the reflected light from below^ simply by providing a heavy or fairly dense sunglass lens both above and below a narrow tyre slit through which the wearer views the field of vision. Glass of this • latter type has also been affected by various defects, mainly1 due to the fact that unless the fields above and below the viewing aperture or transverse slit are opaque or substantially opaque, the wearer is again exposed to significant glare from the reflected light through the lower field and significant direct sunlight through the upper field. If the fields are opaque, the wearer is then limited to seeing only through the region of the viewing aperture which extends across. This would of course cause problems as already noted above with respect to not being able to see the ski tipsJ a speedometer when driving a car etc.

Consequently, there has been a significant need for a sunglass lens of a type where direct rays from the sun are essentially masked out from above while allowing the wearer of the sunglasses to have a significant field of vision upwards through the sunglasses and correspondingly allowing the wearer to have a significant field of vision downwards under the sight opening while again masking out the reflected cutting light from below.

Generally, sunglasses have been provided to be worn by a person where the lens of the sunglasses consists of a plurality of laterally extending, transparent fields which are respectively arranged one above the other. The fields are curved around the wearer's face

in the vertical and horizontal planes, where one of the fields is open to form an extended viewing opening. Slats extending in the longitudinal direction are arranged within each of two other fields flanking the viewing opening, above and below. The slats are arranged in their fields in a distance-wise relationship respectively above each other to form partially transparent masking fields above and below the opening field. The slats for the fields above and below the opening field are tilted upwards and downwards, respectively, seen from the carrier, at progressively increasing angles relative to the horizontal at positions determined respectively at an increasing distance from the opening field.

The present invention aims to provide an improved sunglass holder and a method of manufacture

IN

of the sunglass lens, in which lens direct sunlight from above and cutting light from below are essentially masked so that

it is not seen, while expanding the field of vision for the wearer both upwards and downwards, whereby the objects in the immediate foreground can be seen while looking straight ahead.

The sunglass lens according to the invention is characterized by the fact that the sunglass lens is formed from a flat thermoplastic substrate in which are embedded opaque lamellas placed perpendicular to the surface of the substrate, which substrate is made arc-shaped both on a vertical and a horizontal axis,

and that the slats, as a result of the aforementioned arching, are given progressively increasing angles from a horizontal plane. According to a further feature of the sunglass lens, in said arc-

shaped substrate formed a plurality of laterally extending transparent fields which are arranged one above the other where one of said fields is not provided with lamellas and where the other fields respectively located above and below said lamella-free fields are provided with lamellas.

The method for manufacturing the sunglass lens is characterized by said substrate being heated to a temperature sufficient to make said substrate soft and pliable, and said substrate being bent while in this state around a forming piece to curve the substrate in vertical and horizontal planes for in this way to slant-

set said slats in the vertical plane with progressively ok-

end angles corresponding to the degree of bowing for the substrate.

Figure 1 shows a perspective view of the sunglasses according to the invention. Figure 2 shows a side view sectional view of Figure 1 along the line 2-2. Figures 3 and 4 show enlarged detailed parts of Figure 2 respectively along the lines. 3-3 and 4-4 of this figure to demonstrate the masking effect of the slats at an ever-increasing angle. Figure 5 shows a schematic end view of a laminated substrate blank to be used to produce the lens 10 in Figure 1. Figure 6 shows an enlarged detail view of Figure 5 along the line

6-6 in this latter figure.

Figure 7 shows a schematic view of a draping stop mold and heating means for shaping the substrate blank 31 around the mold.

With reference to figure 1, a pair of sunglasses is shown in a state where they can be worn, which pair of sunglasses has a lens unit 10 comprising a plurality of three laterally extending transparent fields 11, 12, 13 arranged respectively above each other as worn by the wearer. All fields 11, 12, 13 are curved over the wearer's face in the vertical and horizontal planes.

The field 12 is constructed of completely transparent material, preferably thermoplastic. The other two fields 11, 13 are also made of transparent plastic material, but are formed to include opaque lamellae 14, 16. thus they form longitudinally extending and extremely thin lamellae, measuring 0.00076 cm, the central layer 17 for the lens 10.

The slats 14, 16 for the central layer 17 are arranged in a distance-wise relationship respectively above each other at distances of the size of 0.025 cm to form partially transparent masking sf felt above and below the opening field 12. In this regard, it is immediately clear that if the slats 14, 16 are all horizontal, they will limit the eye's view towards the foreground and high up when looking straight ahead through the opening field 12. The layer 17 has a thickness of 0.0076 cm.

The material for the lens 10 can be provided using the method and techniques known from U.S. Pat. patent 3 524 789 or others. According to such a patent, a number of circular, transparent plastic discs are supported on a rolling blank or spindle, where such discs have alternately appearing opaque surfaces and are stacked on top of the rolling blank. By then applying heat and compression to the mass of plastic material, one in all is provided. substantially solid cylindrical block of such alternating material having similarly oriented, alternating opaque surfaces. A slitting knife is then used to peel off a plate from the cylindrical roll of material while simultaneously applying heat from the heat lamps to soften the material. Parts of this plate are used as a uniform lens blank which is comprised of several laterally arranged fields, one above the other. Thus is

. it is relatively easy to provide slats in openings where

it is desirable, and where a transparent opening field is desired, completely transparent discs of plastic material are inserted which have no opaque surfaces.

By providing a number of disks on a rolling blank which

described in the above-mentioned patent, the opaque surfaces provide lamellae. which are perpendicular to the surface of the sheet of material peeled from the cylindrical roll of material.

A procedure is carried out as described further below for

to direct the plane of the slats 14 downwards and forwards and to direct the slats 16 upwards and forwards so as to provide the upper and lower sets of slats at progressively increasing angles

relative to the horizontal at the positions defined

are respectively at an increasing distance from the center plane through the opening field 12. This expands the foreground image through,

the lens and expands the superimposed image through the lens while the wearer directs his gaze directly via the central plane of the aperture field 12.

The central layer 17 provides lamellar portions to

the upper and lower fields 13, 11 as well as the lamella-free clear field 12. The rear surfaces of the lens 10 are covered with a gray colored layer 18 which forms a body layer of suitable semi-flexible plastic, such as cellulose acetate butyrate or polycarbonate, to reduce the internal reflections from solar

the glasses originating from rays coming from behind relative to the wearer's head. The thickness of the layer 18 is of the order of magnitude 0.142 cm to thus provide a substantial protective and supporting body strength to the lens.

The front surface layer of the lens 10 is also similarly covered with a layer 19 of protective plastic such as the above-mentioned thermoplastic, to prevent scratching of the lens surface, etc., and has a thickness of the order of 0.013 cm In the production of the layer material used with respect to the lens 10, three layers are laminated together by conventional means such as adhesive anchors, bonding or adhesives, and the like.

In order to tilt the lamellae 14, 16 respectively downwards and upwards, the laminated substrate structure or blank 31 (Figure 5)

which consists of the layers 18, 19, and the central layer 17 of lamellas equipped with their lamellas essentially perpendicular to the plane of the layers.' (when formed as a surface layer) . The preformed thermoplastic flat substrate or blank 31 is heated by means of the heat lamps 32 to a temperature which is sufficient to make the substrate or blank 31 compliant. A shape 33 is then bent to round the substrate in the vertical and horizontal planes, thereby forming a complex rounding of the shape shown in order to arrange the lamellae at angles that correspond to the bending degrees of the substrate blank.

When the lens 10 has been shaped in this way, the lens is arranged to be fastened on the head of a skier, for example, by means of a pair of connecting straps 21, 22. The straps 21, 22 can have the end portions arranged to lie directly opposite each other and be of interlocking type, e.g. as sold under the trademark "Velcro" which is characterized by a number of very small interlocking hooks and which hold securely against the longitudinal tensile forces, but which will be easily released by tearing one of the strap ends from the other.

Thus the straps 21, 22 are threaded through essentially vertical slits 23 which are formed at the rear ends of the lens 10.

Behind and along the upper edge frame 24 of the field 13, a foam or other compliant sealing material is attached by means of adhesives or binders or in some other way so as to be adapted to engage with the forehead of the wearer of the sunglasses. Consequently, a sealed boundary surface is provided between the forehead of the wearer and along the inner surface of • the upper sealing part 26. The sealing is continued downwards along the rear side parts of the lens 10 in a similar manner5 whereby in the case of foam or other compliant sealing material, it is arranged essentially vertically in the band or strip 27 which is located directly in front of the slits 23. A lower seal is similarly formed by means of a foam or other compliant sealing material placed along the bottom edge frame 28. A silicone rubber or molded vinyl nose piece 29 comfortably supports the lens IO on the wearer's nose in a way whereby the center plane of the viewing opening field 12 will be arranged at the wearer's eye level.

Thus figure 4 illustrates the masking effect for the slats 14 at the lower parts of the field 11, while the slats. 14 at the upper part of the field 11 provides a limited masking with good visibility as shown in Figure 3.

Bearing the foregoing general explanation in mind, the particular dimensions of a useful lens construction and its composition according to the invention consist of a body layer 18 of gray colored cellulose acetate butyrate or polycarbonate having a thickness on the order of 0.142 cm, a central thickening or layer 17 of lamellae with a thickness of the order of 0.0076 cm, and a front cover layer 19 of cellulose acetate butyrate of a thickness of the order of 0.0127 cm. - The distance between the lamellae for the bending or draping formation of the flat laminated material is of the order of 0.025 cm, and the thickness of the lamellae is in the order of 0.00076 cm.

Accordingly, there has been provided an improved sunglass of a type in which the lens serves to shield the eyes of the wearer completely from the high angle rays of the sun and the cutting light from the immediate foreground, while otherwise generally increasing the vertical angle of operation through the lamellar portions of the lens .

Claims (3)

1. Sunglasses lens for sunglasses of a type to be worn of a person, where the lens is arc-shaped around the wearer's face and with a lamellar structure designed to shield light from selected directions, characterized in that the sunglass lens is formed from a planar thermoplastic substrate in which opaque lamellae arranged perpendicular to the surface of the substrate are embedded, which the substrate is made arc-shaped both about a vertical and a horizontal axis, and that the slats as a result of said arc shaping are given progressively increasing angles from a horizontal plane. 2. Sunglass lens as stated in claim 1, characterized in that a plurality of laterally extending transparent fields are formed in said arc-shaped substrate which are arranged one above the other, that one of said fields is not provided with lamellae and that the other fields are respectively located above and below said slat-free fields are provided with slats. 3. Method for producing a sunglass lens as stated in claims 1 and 2 by using a preformed multi-layer laminated, thermoplastic substrate which includes opaque lamellae or the like. arranged within the substrate and normally on the plane of the substrate, characterized in that said substrate is heated to a temperature sufficient to -make said substrate soft and yielding, and that said substrate is bent while in this state around a forming piece to curve the substrate in vertical and horizontal planes in order in this way to incline said lamellas in the vertical plane with progressively increasing angles corresponding to the degree of boyning for the substrate.