Method for covering a lens blank with a protective plastic film

A method for covering a concave face of a glass blank with a piece of protective plastic film comprising the steps of:

• positioning the blank and the piece of film in juxtaposition but separate, the outer edge of the piece of film being unrestrained for upward movement by a holding device on which said film is mounted, said blank and and piece of film being positioned substantially horizontally and aligned so that said blank is directly above said piece of film, the piece of film having an area being approximately equal to the area of the concave face of the glass blank;
• applying gas pressure nonuniformly to said piece of protective film so as to propel the entire piece of film upward toward the concave face of the blank so that contact between the piece of film and the concave face of the blank is made initially at one point at a central portion of the concave face of the blank and so that contact between the piece of film and the concave face of the blank advances radially outward from the initial contact point toward the edge of the concave face of the blank, said piece of film being supported while being propelled toward said blank only by said gas pressure;
• and
• applying sufficient heat and pressure to joint the piece of film and the blank.