Optical proximity sensor for a liquid-jet instrument, and a liquid-jet instrument equipped with such a sensor

An optical proximity sensor adapted to be mounted in a liquid-jet instrument having a spray head for spraying a jet of liquid, the optical sensor serving to evaluate a distance between the optical sensor and a given surface onto which the liquid is to be sprayed, the optical proximity sensor comprising:

• a printed circuit having a first face and a second face on which at least one light-emitting element and at least one light-receiving element are positioned, the light-emitting and the light-receiving elements being adapted to evaluate the distance between the light-emitting and the light-receiving elements, and the given surface;
• an intermediate part mounted on the second face of the printed circuit, and includes at lest two through recesses in which the light-emitting and the light-receiving elements of the printed circuit are received;
• and
• protective means that cover at least one of the two through recesses, the protective means presenting optical properties adapted to the wavelength of the light used by the light-emitting and the light-receiving elements so as to enable the light to be focused,
• wherein the printed circuit and the intermediate part are provided with through holes which are mutually superposed to form a passageway serving to enable the liquid to be sprayed from the liquid spray head,
• wherein the printed circuit further comprises a rigid board disposed against the intermediate part, and conductive tracks formed on the first face of the printed circuit, and
• wherein the conductive tracks are adapted to power the light-emitting and the light-receiving elements, and to convey the signals from the at least one light-receiving element to a processor unit.

An optical proximity sensor adapted to be mounted in a liquid-jet instrument having a spray head for spraying a jet of liquid, the optical sensor serving to evaluate a distance between the optical sensor and a given surface onto which the liquid is to be sprayed, the optical proximity sensor comprising:

• a printed circuit having a first face and a second face on which at least one light-emitting element and at least one light-receiving element are positioned, the light-emitting and the light-receiving elements being adapted to evaluate the distance between the light-emitting and the light-receiving elements, and the given surface;
• an intermediate part mounted on the second face of the printed circuit, and includes at least two through recesses in which the light-emitting and the light-receiving elements of the printed circuit are received;
• and
• protective means that cover at least one of the two through recesses, the protective means presenting optical properties adapted to the wavelength of the light used by the light-emitting an the light-receiving elements so as to enable the light to be focused,
• wherein the printed circuit and the intermediate part are provided with through holes which are mutually superposed to form a passageway serving to enable the liquid to be sprayed from the liquid spray head,
• wherein the printed circuit further comprises a rigid board disposed against the intermediate part, and conductive tracks formed on the first face of the printed circuit,
• wherein the conductive tracks are adapted to power the light-emitting and the light-receiving elements, and to convey the signals from the at least one light-receiving element to a processor unit,
• wherein the second face of the printed circuit is provided with a plurality of light-emitting and light-receiving elements,
• wherein the intermediate part is provided with a plurality of through recesses in which the plurality of light-emitting and light-receiving elements are received,
• wherein the protective means cover the plurality of recesses, and
• wherein the protective means include a transparent plate.