Apparel – Guard or protector – For wearer's head
Reexamination Certificate
2000-09-01
2001-12-04
Calvert, John J. (Department: 3741)
Apparel
Guard or protector
For wearer's head
Reexamination Certificate
active
06324702
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a double lens for skiing goggles with a curved outer lens and an equally curved inner lens, made of a cellulose propionate foil, that is arranged at a distance from the outer lens and connected with the outer lens via a sealing strip on the edge.
DESCRIPTION OF THE PRIOR ART
To avoid fogging of the lens of skiing goggles with condensed steam as far as possible, it is known to apply double lenses interconnected at a distance to each other via a sealing strip on the edge. The heat insulation due to the air space between the outer and the inner lens provides for an appropriate temperature difference between the two lenses, whereby, because of the related shifting of the dew point, the tendency of fogging of the lens is clearly reduced compared with a single lens, particularly when both lenses are made of a material with a surface quality impeding fogging with condensed steam, as this is the case with cellulose priopionate foils. However, the disadvantage of the double lenses made of cellulose propionate foils is that these foils have a comparably low mechanical strength and can therefore not be considered scratch-resistant. Furthermore, in spite of the double lens design of the lens and the favorable fogging behaviour, there may still be fogging of the lens with condensed steam under unfavorable conditions of temperature and humidity, which impedes the vision through the skiing goggles.
SUMMARY OF THE INVENTION
The invention has therefore the objective to design a double lens for skiing goggles of the above mentioned kind in such a way that not only the mechanical strength of the lens is increased, but that the fogging behaviour is improved, too.
The objective is achieved by the feature that both the outer lens, made of injection-molded polycorbonate, and the inner lens, made of vacuum-formed cellulose propionate foil, are curved spherically and that the outer lens is provided with a hygroscopic layer on its inside.
Compared with conventional skiing goggles, which are provided with a cylindrical curvature to adapt the skiing goggles to the head shape, the air volume enclosed by the skiing goggles between the head of the wearer and the lens is increased because of the spherical curvature of both the outer and the inner lens, which has a favorable effect on the fogging behaviour of the skiing goggles, and in fact to a surprising extent. As the outer lens is manufactured of polycarbonate in an injection molding process, the desired curvature is achieved relatively easily via an appropriate design of the mold. However, as far as the spherical curvature of the inner lens is concerned, there are difficulties, as it is made up of a cellulose propionate foil that, for optical reasons, cannot easily be reshaped. Only by way of vacuum-forming of the applied cellulose propionate foil the desired spherical curvature of the inner lens can be ensured without adversely affecting the optical quality of the lens, provided that molecule drawing during deep-drawing is kept accordingly low.
To be able to combine a high resistance to breakage with a good scratch resistance, it is known to manufacture lenses of polycarbonate. However, with the application of polycarbonate lenses, the particularly good fogging behaviour of cellulose propionate foils is given up. As an embodiment of the lens according to the invention combines an outer lens of polycarbonate with an inner lens of a cellulose propionate foil, and as the inside of the outer lens is additionally provided with a hygroscopic coating, this disadvantage otherwise occurring with lenses of polycarbonate is of no consequence, so that, by combining the specified measures together with the spherical curvature of the lens, a low tendency to fogging of such a lens is achieved, even under unfavorable conditions of temperature and humidity.
REFERENCES:
patent: 1562350 (1925-11-01), Luckey
patent: 3705760 (1972-12-01), Langendorfer et al.
patent: 5018223 (1991-05-01), Dawson et al.
patent: 5555038 (1996-09-01), Conway
patent: 5642530 (1997-07-01), Parks
patent: 5668618 (1997-09-01), Simioni
patent: 1 091 871 (1960-10-01), None
patent: 2 317 088 (1974-10-01), None
patent: 0 446 698 (1997-05-01), None
patent: 524196 (1939-08-01), None
patent: 2284679 (1995-06-01), None
patent: WO92/07630 (1992-05-01), None
Calvert John J.
Collard & Roe P.C.
Moran Katherine
Silhouette International Schmied GmbH & Co. KG
LandOfFree
Looking glass for ski goggles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Looking glass for ski goggles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Looking glass for ski goggles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2580081