抄録
High-speed stacking two-dimensional bar-code detection systems under time-sharing light emission operation, which are highly useful in applications such as goods management on production lines and in automated warehouses, require a longer detection range to obtain highly reliable detection. A new stacking two- dimensional bar-code detection system is proposed in which a wide-angle detection lens is used to increase the amount of light incident on a photodiode after reflection from a barcode. Composite masked collimators are also employed to uniformly extend the depth of focus for three laser diodes. The best performance was obtained using composite masks with holes of 2.5 and 3 mm in diameter and a condensing lens with 40-mm aperture and 28.5-mm focal length. This system provides a long detection range of 14.2 cm for 0.25-mm 3-line barcodes, which is 1.38 times longer than that of conventional systems. This long range has potential application in high-speed, high-resolution barcode systems.
