Abstract: A motor vehicle seat has a strength-member for its back that includes an upper portion pivotally mounted on a lower portion and carrying a headrest, the two portions of the strength-member are connected together by a locking device which holds them together and which is dimensioned to give way when the back of a passenger bears against a thrust member of the upper portion of the strength-member in the event of an impact from behind, such that the upper portion of the seat-back strength-member and the upper region of the front face of the seat-back then pivot forwards together with the headrest, with this movement being braked by an energy absorber device.

Abstract: A high impedance electrooptical transducer, such as for use in an optical output sensor. The transducer includes an electrosensitive element that emits photoluminescence radiation when illuminated by an excitation radiation. The electrosensitive element includes conjugate photoluminescent oligomers. The photoluminescence efficiency of the conjugate oligomers varies in the presence of an electrical field.

Abstract: A transparent, organic polymer substrate organized for optical frequency conversion is prepared by subjecting a material of a transparent, organic polymer which incorporates therein transparent, active organic molecules which have a second order, microscopic, optical nonlinearity to the simultaneous action of a first laser beam at fundamental frequency .omega. and a second laser beam of second harmonic frequency 2 .omega. for a time adequate to induce a second order, macroscopic nonlinearity in the transparent active organic molecules in the structure.