Online guide for lenses and treatment used by giarre.com > Hi-P. Policarb. EX1.59 Asph.
The new line of lenses in policarbonate at extrusion Hi-Performance Policarbonate EX 1.59 Aspheric Full Top with anti-scratch, anti-reflection and antistatic treatments identifies all the advantages of the lenses in policarbonate such as the Hi-Performance Policarbonate SP, avoiding the problem of 'Cracking'.See the results of this new lense at extrusion:
- The traditional lense in policarbonate
The lenses in policarbonate have been an important innovation in the world of glasses. Thanks to the structural features of this material (which was used only for the security needs at the beginning), the experts have been able to offer solutions of forming the frame, such as the rimless frames, which permitted esthetical results according to the development of the stylistic fashion-lines. The negative aspect of the lenses in policarbonate was dued in particular to the properties of homogenity and visual isotropy, inferior in comparison with the traditional materials of the ophtalmic field. Another inconvenient, which can be found in the forming of frames with boring of the lenses, is the 'cracking', small splittings dued to internal tensions of policarbonate, which in long time weakens the area of fitting. - The problem with traditional policarbonate
The studies of the past years have enabled to identify the reasons of the problems, connected with the structure of the policarbonate. The experts have noticed that the high tensional state remaining of the lenses, dued to the printing process, creates phenomenon of birefringence (different and uncontrolled journeys of the visual light rays), which cause a decrese of the resolution power of the visual way. These tensions favour the 'cracking'. The tensional state of each ophtalmic lense can be easy verified from everyone with the helping of a simple instrument, called Polariscope. - The new technologies of production
The internal tensions of the usual lenses in policarbonate are caused in particular by the production process, which consists in the Printing by injection with high pressure (higher than 200 bar) and high temperature (within 300 grades). The searching of least stress methods for the material, originated by the necessities of the visual field, has produced the Printing at extrusion. Even if it requests for more sophisticated equipping and more expensive working methods, enables to decrease of about 40 Grades the standard temperature of the fluid mass of policarbonate during the printing. - The result: Policarbonate EX
The new Hi-Performance EX lense is the result of this innovation of technology production. The exam with the polariscope underlines immediately and with clearness the high isotropy of the material, thanks to which the phenomenon of birefringence are cancelled. More than a visual precision and the recovery of the resolution power, a less irritated internal tensional state produces immediate advantages in the frame's fitting, eliminating the problems of splitting and cracking during the boring period. In order to increase the exceptional features of this material, the whole range of monofocal and progressive EX lenses is combined with the aspheric and atoric.
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