Abstract: A sensor system includes a reader side resonant circuit (10) and a sensor side resonant circuit (20). The reader side resonant circuit (10) is an LCR parallel resonant circuit and a gain circuit. The sensor side resonant circuit (20) is an LCR parallel resonant circuit and a loss circuit having, as a resistance portion, a sensor element whose resistance value changes according to an object to be sensed. The reader side resonant circuit (10) and the sensor side resonant circuit (20) are wirelessly connected to each other through magnetic field resonant coupling to constitute a gain-loss coupling circuit, and the reader side resonant circuit (10) and the sensor side resonant circuit (20) are formed such that the gain-loss coupling circuit has parity-time symmetry.

Abstract: A retro-reflective sheet includes: a retro-reflective layer (20) including a plurality of retro-reflective elements (24) on one surface; and a back face layer (30) provided to face the surface of the retro-reflective layer on the retro-reflective elements side. A part of the retro-reflective layer and a part of the back face layer are bonded to each other via a coupling portion (34) colored in a color other than white. Voids (36) are formed between another part of the retro-reflective layer and another part of the back face layer. The color of the coupling portion is different from colors of layers provided on a side opposite to the back face layer side from the voids.

Abstract: The present invention on provides retroreflective sheeting (100) having at least two types of set images (L1, L2) adjacent to one another each termed as a set of a number of points of image (P1, P2) that are directionally visible in a predetermined direction.

Abstract: [Object] A retroreflective sheeting that is provided with a set image having excellent anticounterfeit characteristic and information transmission characteristic is provided.