Patent ID: 11937923
Assignee: WITHINGS
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 19:
20. A device comprising:
a light emission assembly comprising an infrared LED to emit an infrared light ray with a first wavelength at a first position, a red LED to emit a red light ray with a second wavelength at a second position, and a green LED configured to emit a green light ray with a third wavelength at a third position,
a broadband photodiode configured to receive the red and infrared light rays, and a selective photodiode configured to receive the green light ray,
a control unit,
wherein the broadband photodiode is at a fourth position and the selective photodiode is at a fifth position, and
wherein a distance between the third position and the fifth position is at least 2 mm,
wherein the device is formed as a single unit and the control unit is configured to carry out a method to determine a current functional blood oxygen saturation level, the method including
acquiring, at a predefined sampling frequency, a photoplethysmography light response for each of the first, second and third wavelengths, resulting respectively in a first, second and third raw data series representing an amplitude response through a user's tissue,
applying a low-pass filter to each of the first, second and third raw data series, resulting respectively in a first, second and third DC data series representing an unmodulated amplitude response,
applying a high-pass filter to each of the first, second and third raw data series, or subtracting respectively first, second and third DC data series to said first, second and third raw data series, to result respectively in a first, second and third AC data series representing an unmodulated amplitude response, and
applying a computation engine to the first, second and third AC data series, and to the first, second and third DC data series, and determining therefrom a user current blood oxygen saturation level.