In a conventional area sensor, slim objects cannot be detected since the emitting and the receiving elements are scanned synchronously as a set. In contrast, in Panasonic NA1-11, only the elements 1 to 11 of the emitter are scanned to obtain emission. The elements of the receiver are not scanned, so that when element 1 of the emitter emits light, all the elements of the receiver receive light. Hence, even if there is one element on the receiver which does not receive light, it results in light interrupted operation. With this technique, detection of slim objects is possible. Slim objects can be detected by the cross-beam scanning system. A minimum sensing object size of ø13.5 mm ø0.531 in can be detected by an emitting and receiving element pitch of 10 mm 0.394 in. Though being extremely slim, it has a wide sensing area of 1 m 3.281 ft length and 100 mm 3.937 in width. It is most suitable for object detection on a wide assembly line, or for detecting the dropping of, or incursion by, small objects whose travel path is uncertain. It is extremely slim, being just 10 mm 0.394 in thick. Further, it can be mounted in a narrow space as you can select from two cable orientation directions.