Optical sensor arrangement and method for manufacturing an optical sensor arrangement

A method for manufacturing an optical sensor arrangement for time-of-flight measurement, the method comprising

• providing a cover arrangement with a translucent or transparent plate and with one or more layers of material arranged on an inner main surface of the plate;
• providing a housing body with a first and a second cavity separated by an optical barrier, wherein an optical emitter is arranged in the first cavity and a measurement photodetector and a reference photodetector are both arranged in the second cavity;
• and
• attaching the cover arrangement to the housing body such that the cover arrangement covers the first and the second cavity;
• wherein
• the one or more layers comprise an opaque coating with a first and a second aperture located above the first cavity, and with a third and a fourth aperture located above the second cavity;
• the emitter is arranged and configured to emit light through the first aperture, and the measurement photodetector is arranged and configured to detect light entering the second cavity through the fourth aperture;
• and
• the second and the third aperture establish a reference path for light from the emitter to the reference photodetector;
• wherein a mutual arrangement of the emitter, the reference photodetector, the second aperture and the third aperture is adapted such that fractions of light emitted by the emitter enter the plate through the second aperture, are at least partially reflected at an outer main surface of the plate, enter the second cavity through the third aperture, and hit the reference photodetector.