Interaction interface comprising: - a touchscreen covered by a substantially flat protective plate that is at least partly transparent in the visible radiation range and that has an inner face oriented towards said touchscreen, and - a proximity detector including at least one emitter (203, 205, 207, 208, 209, 211, 212, 213, 215, 217, 218) radiating in an infrared range and at least one receiver (206, 210, 216) designed to detect radiation in said infrared range, each emitter and each receiver (206, 210, 216) being situated on the perimeter of said touchscreen, wherein said protective plate: - is transparent in said infrared radiation range, - covers each emitter (203, 205, 207, 208, 209, 211, 212, 213, 215, 217, 218) and each receiver (206, 210, 216), - and has, on its inner face, at least one zone, situated opposite each emitter (203, 205, 207, 208, 209, 211, 212, 213, 215, 217, 218) and each receiver (206, 210, 216), covered with a first coating that is more transparent in said infrared radiation range than in the visible radiation range, characterized in that the interaction interface furthermore comprises: - a light guide having the shape of a truncated cone whose truncated apex is oriented towards at least one of said emitters, and whose axis is substantially perpendicular to a printed circuit board on which said emitter is mounted, and is centred on said emitter, and the lateral surface of said truncated cone is at least partially reflective in the infrared radiation range used by the proximity detector of the interaction interface - an optical component performing both the function of a convergent lens, thus reducing the divergence of a beam of light rays passing through it, and the function of a prism, deflecting the mean direction of said beam, said optical component being situated between the light guide and the inner face of the protective plate, the base of the light guide and the entry face of the optical component being inclined overall with respect to one another. - a touchscreen covered by a substantially flat protective plate that is at least partly transparent in the visible radiation range and that has an inner face oriented towards said touchscreen, and - a proximity detector including at least one emitter (203, 205, 207, 208, 209, 211, 212, 213, 215, 217, 218) radiating in an infrared range and at least one receiver (206, 210, 216) designed to detect radiation in said infrared range, each emitter and each receiver (206, 210, 216) being situated on the perimeter of said touchscreen, - is transparent in said infrared radiation range, - covers each emitter (203, 205, 207, 208, 209, 211, 212, 213, 215, 217, 218) and each receiver (206, 210, 216), - and has, on its inner face, at least one zone, situated opposite each emitter (203, 205, 207, 208, 209, 211, 212, 213, 215, 217, 218) and each receiver (206, 210, 216), covered with a first coating that is more transparent in said infrared radiation range than in the visible radiation range, characterized in that the interaction interface furthermore comprises: - a light guide having the shape of a truncated cone whose truncated apex is oriented towards at least one of said emitters, and whose axis is substantially perpendicular to a printed circuit board on which said emitter is mounted, and is centred on said emitter, and the lateral surface of said truncated cone is at least partially reflective in the infrared radiation range used by the proximity detector of the interaction interface - an optical component performing both the function of a convergent lens, thus reducing the divergence of a beam of light rays passing through it, and the function of a prism, deflecting the mean direction of said beam, said optical component being situated between the light guide and the inner face of the protective plate, the base of the light guide and the entry face of the optical component being inclined overall with respect to one another.