Patent ID: 11921955
Assignee: NEDERLANDSE ORGANISATIE VOOR TOEGEPAST-NATUURWETENSCHAPPELIJK ONDERZOEK TNO
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 7:
8. A proximity sensitive display element including:
a light guide comprising a substrate with a first main side and a second main side mutually opposite to each other and respectively having a first and a second reflective layer with a reflective inner surface facing inside the light guide, a translucent window being defined at the first main side to allow optical radiation to enter and to leave the light guide, the translucent window having an outer surface;
a light emitting element accommodated within the light guide;
a plurality of mutually different proximity sensors comprising at least an infrared (IR) proximity sensor that is arranged at the second main side of the substrate and that faces the first main side through a semi-transparent patch in the second reflective layer; and
at least a further proximity sensor comprising an optical radiation sensor for sensing optical radiation in the visible range that is arranged at a side of the translucent window opposite the outer surface, which optical radiation sensor is configured to:
receive a portion of the optical radiation that is reflected by the human finger towards the optical radiation sensor via the translucent window, and
provide a sense signal representative of the portion of the optical radiation,
wherein the sense signal comprises:
a first signal component indicative of a red spectral component of the portion of the optical radiation, and
a second signal component indicative of a green spectral component of the portion of the optical radiation; and

wherein a signal processor is configured to
receive the sense signal,
determine a first value of the first signal component and a second value of the second signal component relative to a respective nominal value;
compute a ratio between the first value and the second value; and
provide, based on the ratio, an estimate of a pressure exerted by the human finger on the outer surface;

wherein the proximity sensor module further comprises an output unit to generate a resultant proximity signal based on input proximity signals issued by the plurality of mutually different proximity sensors, and
wherein the output unit comprises a selection unit and a controller to cause the selection unit to select an input proximity signal from a specific one of the plurality of proximity sensors if an estimated value for that sensor is within a sensitivity range of that proximity sensor.