The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 06, 1998
Filed:
Jan. 21, 1998
Stephen D Tuomela, Oakdale, MN (US);
Joel A Fischer, St. Paul, MN (US);
Modern Controls, Inc., Minneapolis, MN (US);
Abstract
An apparatus for measuring the gas transmission rate through contact lens material, and a method of measuring, using a test cell having an upper and lower gas chamber and separating the upper and lower chamber with a layered group of films, including a contact lens film material clamped between an upper and lower guard film, and flowing oxygen through the upper chamber and an inert gas through the lower chamber, the lower chamber being connected to a coulometric sensor to measure oxygen content in the inert gas at defined intervals, to obtain a first series of oxygen transmission rates. A second series of oxygen transmission rates are made with the same apparatus, but with the contact lens material removed from the apparatus, and the transmission rate through the contact lens material is calculated by subtracting the reciprocal of the second measured transmission rate from the reciprocal of the first measured transmission rate, then taking the reciprocal of the difference.