Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
2000-12-05
2004-04-06
Aftergut, Jeff H. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S285000, C156S295000, C156S362000, C156S556000, C156S559000, C264S001340, C264S101000
Reexamination Certificate
active
06716294
ABSTRACT:
The present invention relates to plant and process for automatically gluing polarising lenses.
More specifically, the invention relates to plant and process of the above kind allowing to obtain in a completely automatic manner a so called “coupled” polarised lens (lens-film-lens) having a null power, to be used for sunglasses.
In other words, the invention allows to automatically produce polarised blanks for the subsequent production of glass lenses.
Coming now to provide as an introduction some information concerning the polarising lenses, it is well known that visible light is comprised of electromagnetic waves, having a wavelength approximately between 380 and 780 nm.
Other features of the luminous radiations are the radiation intensity ad geometry of the electromagnetic wave oscillation.
As to the oscillation geometry, also known as “polarisation”, it can occur according to randomly oriented planes, also known as “random polarisation” or “non polarised”, or according to a single plane (“linear polarisation”), i.e. within a cylindrical surface (“circular polarisation”).
Naturally, light usually is not polarised. Reflection on reflecting surfaces (glazed doors, water surfaces, snow or ice surfaces, bright or wet asphalt) and having suitable angles, produces a certain degree of polarisation.
The effect is that of a glow coming from the zone of the surface where the polarised reflection is maximum. A remarkable inconvenience for the view is caused by the strong reflection. For example, this effect, on the water surfaces, prevents the vision under the water surface.
Polarising lenses are able to filter direct light as a standard “sun” lens and to eliminate (according to a certain degree of efficiency, polarised reflected light which is particularly troublesome.
Main comfort is the elimination of the fastidious reflexes normally present on the glazed doors, water mirrors, iced surfaces and asphalted roads.
Glasses polarised lenses are usually comprised of two thin lenses between which the polarising film is interposed.
Lenses and film are coupled by an adhesive placed on both faces of the film, thus realising an assembly having five layers:
outer or “convex” lens;
glue;
polarising film;
glue;
inner or “concave” lens”.
Additional outer or inner layers can be comprised of surface treatments to confer to the lenses particular esthetical or mechanical properties.
Optical properties of the whole assembled lens depends on the properties of the single layers and also on the geometrical regularity of the assembling phase. A uneven amount of glue, or non-parallelism among the different layers, produces optical effects not acceptable for the finished product (aberrations, distortions and optical definition loss).
The known assembling technique provides the use of preformed film (i.e. already curved by the manufacturer) and then the manual gluing after having applied the adhesive on both the film surfaces.
Then, adhesive is catalysed by UV lamps.
It can be easily understood that such a process does not ensure concentricity of filtering and transparent layers and thus of the liquid layers (adhesive) before the catalysation, with the consequent above mentioned optical defects.
Manual assembling operations are very expensive since they require a very long time and they must be carried out paying a great care by skilled personnel to avoid and eliminate air bubbles produced during the approaching of the lenses to the adhesive and already present on the same adhesive.
This kind of solution is shown for exemplificative purposes in
FIG. 1
a.
Up to date, the Applicant has privileged the production of glass polarising lenses, since the precision and geometrical stability of the lenses which are optically worked are preferred.
Generally speaking, technology employed until today to glue the lenses provides the shaping of the polarised film by different methods and then the manual gluing after having placed the adhesive on the two film surfaces.
Afterwards, catalysation of the adhesive is carried out by UV lamps.
Process according to the prior art does not ensure the concentricity of the filtering and transparent layers and thus the thickness of the liquid layers (adhesive), before catalysation.
Consequently, a series of optical defects occur such as aberrations, distortions and optical definition loss.
It is well evident that manual assembling operations are very expensive since they require a very long time and they must be carried out paying a great care by skilled personnel to avoid and eliminate air bubbles produced during the approaching of the lenses to the adhesive and already present on the same adhesive.
Main object of the present invention is that of solving the above mentioned drawbacks characteristic of the manual workings.
Particularly, the solution according to the present invention allows to obtain a high optical precision of the spherical surfaces comprising the lens, thus eliminating defects (air bubbles, ecc.).
Furthermore, the invention avoids any risk of low productivity, or in any case the need of a high number of personnel, being the process completely automated, and allows to obtain a high productive repetitiveness and a remarkable average quality standard.
These and other results are obtained according to the invention, providing improvement in the under vacuum application and shaping of the polarising film, in the prism, optical definition and aberration defects elimination, by the control of the curvature rays and of the thickness of the five layers comprising the lens, and by the realisation of a completely automatic plant for the realisation of the lens starting from blanks (lenses and polarising film).
It is therefore specific object of the present invention a plant for the continuous production of polarising lenses, comprising a coil polarising film feeding station; a glass convex lens feeding station; a concave lens feeding station; an under vacuum film shaping station on spherical moulds; a deposition and gluing outer convex lens station; a translation station for the pre-glued lenses; a deposition and gluing inner concave lens station; a lens separation and film cutting station; and a palletisation station for the finished lenses, said plant functioning automatically.
In a preferred embodiment of the plant according to the present invention said concave and convex lens deposition and gluing stations provide an approaching motion of the lens to the glue bead in such a way to realise a substantially point contact between lens and glue, without air trapping.
Preferably, according to the invention, the lens is approached to the bead with its axis not coinciding and after the contact a diagonal motion of the lens is realised until centring the same, followed by a slight vertical pressure to preliminarily spread the glue.
Still according to the invention, after said vertical pressure a spiral or circular rotatory motion can be carried out to further spread the and to homogenise the glue.
Preferably, according to the invention, said film fed on a coil is provided on a protection support, in said coil film feeding station a collection coil for the protection support being provided.
Furthermore, according to the invention, downward said glass convex lens feeding station an orienteering station is provided (to apply oriented coatings, such as degrading coatings, or for use with de-centred lenses, wherein optical centre does not coincide with the geometrical centre).
Always according to the invention, upward the palletisation station a marking section to mark the polarisation axis can be provided.
Furthermore, according to the invention, a washing station can be provided, wherein thin lenses to be glued can be washed by an automatic apparatus, employing suitable detergents, ultrasounds, rinsing by demineralised and osmotised water.
Still according to the invention, said washing station can be connected in correspondence of its end part where the washed lenses are returned, with the concave and convex lens feeding stations.
Preferably, according to the invention, two separate w
Aftergut Jeff H.
Barberini S.p.A.
Haran John T.
Young & Thompson
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