A planar detector for use in light curtains, which generates electric signals as a function of absorbed light and is provided with a plurality of tapping points for the generated signals. The magnitude of the signals at the respective tapping points is dependent on their distance to the partial surfaces where the light is absorbed. As a function of the magnitude ratios between the signals at several tapping points, the distance ratios of the respective tapping points to those partial surfaces, where the light is absorbed, can be calculated. The detector is configured as a flexible layered structure made of organic material. The tapping points are disposed at a distance from the edges of the layered structure. Electric connection lines to the tapping points are connected along their longitudinal extension to the layered structure of the detector.