Abstract: A lens for chromatic aberration compensation is provided. The lens includes a lens body and a plurality of color filter films. The lens body has a light incident plane, a light exit plane and an optical axis. The light incident plane and/or the light exit plane comprises a plurality of discrete area, wherein the area comprises, for example but not limited to, a plurality of annular areas, fan-shaped areas, or polygon areas. The color filter films are disposed over the areas of the lens body respectively, and comprise red color filter films, green color filter films or blue color filter films. Accordingly, the lens for chromatic aberration compensation of the invention can eliminate the aberration effectively.

Abstract: A lens for chromatic aberration compensation is provided. The lens includes a lens body and a plurality of color filter films. The lens body has a light incident plane, a light exit plane and an optical axis. The light incident plane and/or the light exit plane comprises a plurality of discrete area, wherein the area comprises, for example but not limited to, a plurality of annular areas, fan-shaped areas, or polygon areas. The color filter films are disposed over the areas of the lens body respectively, and comprise red color filter films, green color filter films or blue color filter films. Accordingly, the lens for chromatic aberration compensation of the invention can eliminate the aberration effectively.

Abstract: A method of determining tag identifications is discloses. The method comprises: providing an index signal; receiving a responsive signal generated from tag matching the index signal; obtaining an identification code corresponding to the responsive signal; reader sending an acknowledgement and waiting for tag to respond a returned-acknowledgement. A searching process is repeated at the current node after a tag responsive signal is received to prevent signal suppression errors.