Patent ID: 7227120

Claim:
A multi-beam photoelectric sensor comprising: a light projection columnar member for accommodating an string of light projectors in a columnar case and a photo-detecting columnar member for accommodating a string of photo-detectors in a columnar case, wherein the light projection columnar member and the light-receiving columnar member are arranged with the light projection surface and the light-receiving surface in an appropriately spaced relation with each other thereby to generate a curtain for detecting an object between the light projection columnar member and the photo-detecting columnar member, wherein the light projector string includes: an arrangement of a plurality of aligned light projection modules each having, integrated with each other, a light projection optical system for one optical axis, a light projection circuit for one optical axis, and a plurality of flip-flops corresponding to one stage of shift register, and a light projection signal transmission member including a common conduction wire for uniformly connecting from a light projection module located at one end of the light projection module arrangement to a light projection module located at the other end thereof and adjacent module conduction wires for connecting only adjacent light projection modules to each other; wherein each light projection module constituting the light projection module arrangement is electrically connected to the light projection signal transmission member; wherein the photo-detector string includes: an arrangement of a plurality of aligned light-receiving optical modules each having, integrated with each other, a light-receiving optical system for one optical axis, a light-receiving circuit for one optical axis, and a plurality of flip-flops corresponding to one stage of shift register, and a light-receiving signal transmission member including a common conduction wire for uniformly connecting from a light-receiving module located at one end of the light-receiving module arrangement to a light-receiving module located at the other end thereof and adjacent module conduction wires for connecting only adjacent light-receiving modules to each other; wherein each light-receiving module constituting the light-receiving module arrangement is electrically connected to the light-receiving signal transmission member; wherein the flip-flops in the adjacent light projection modules are connected to each other in cascade by adjacent module connection wires thereby to constitute a shift register and so are the flip-flops in the adjacent light-receiving modules; and wherein the light-projection modules constituting the light-projection module arrangement and the light-receiving modules constituting the light-receiving module arrangement are sequentially activated by the data sequentially supplied from the shift register.