US PATENT SUBCLASS 351 / 165
.~.~.~ With sections of different light absorption

Current as of: June, 1999
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351 /   HD   OPTICS: EYE EXAMINING, VISION TESTING AND CORRECTING

41  DF  SPECTACLES AND EYEGLASSES {29}
159  DF  .~ Ophtahalmic lenses or blanks {10}
163  DF  .~.~ With light filtering means {2}
165.~.~.~ With sections of different light absorption

DEFINITION

Classification: 351/165

(under subclass 163) Subject matter wherein the lenses have vision areas of different light abosorptive qualities which may differ in density and/or in frequency (e.g., clear or slightly tinted central glass portions and deeply colored surrounding areas).

SEE OR SEARCH THIS CLASS, SUBCLASS:

177, for methods of superposing a clear glass-disk and a glass-disk having its color graduating in strength.