| 摘要 |
The beverage can has a pair of spaced, redundant, arcuately distributed code patches on its lid containing regional redemption information. The code patches are read by a scanning laser beam. These patches may be formed in several different ways, as by impressing them, embossing them, or printing them. Information in the patches may be coded in a binary-type code or in a frequency-type code. - A circularly swept laser beam is used and its impingement with the can lid is reflected, through a suitable optical system, onto a photodetector. The can lid may include two arcuately spaced code patches which are identical, and which afford reading redundancy to obviate errors resulting from defacing or dirtiness of one of the code patches.(1/6) |
