Patent ID: 11857298
Assignee: APPLE INC.
Field: Medical technology (Instruments)
Classification: CPC A  G | IPC A  G

Claim 0:
1. A wearable device, comprising:
a housing;
a wrist band attached to the housing;
a first emitter positioned within the housing and configured to emit, through a back of the housing, a first beam of electromagnetic radiation having a first infrared (IR) wavelength selected from a near-infrared (NIR) band ranging from 750 nanometer (nm) to 1400 nm;
a second emitter positioned within the housing and configured to emit, through the back of the housing, a second beam of electromagnetic radiation having a second IR wavelength selected from a short-wavelength infrared (SWIR) band ranging from 1400 nm to 2000 nm, wherein the second IR wavelength is different from the first IR wavelength;
a photodetector positioned within the housing and filtered to detect a set of electromagnetic radiation wavelengths including the first IR wavelength and the second IR wavelength; and
a matter differentiation circuit configured to indicate, at least partly in response to signals indicating amounts of the first IR wavelength and the second IR wavelength received by the photodetector, whether the back of the housing is likely proximate to a human tissue.