Sensor device to mitigate the effects of unwanted signals made in optical measurements of biological properties

A device to determine a biological parameter of a tissue of a person, the device comprising:

• a display;
• a light emitter configured to emit a first light signal and a second light signal towards the tissue;
• a light detector configured to collect a first received signal and a second received signal that are received from the tissue responsive to the first light signal and the second light signal respectively,
• wherein the light emitter is configured to emit the first light signal at a wavelength within the visible light spectrum, and
• wherein the light emitter is configured to emit the second light signal such that the second light signal is inert to changes in blood vessels of the tissue towards which the second light signal is emitted, such that the second received signal carries substantially only noise;
• wherein the device is configured to convert the first received signal and the second received signal to a frequency domain, represented by respective sets of values in multiple frequency bands, wherein a first set of values in multiple frequency bands represents the first received signal and a second set of values in multiple frequency bands represents the second received signal;
• and
• wherein the device is configured to subtract the second set of values in multiple frequency bands from the first set of values in multiple frequency bands in the frequency domain to obtain a third set of frequency bands, wherein the third set of frequency bands represents a third signal corresponding to the biological parameter of the tissue,
• wherein the device further comprises a component selected from the group consisting of:
• (i) a lens mounted to a distal end of the light emitter and configured to collimate the first and the second light signals as collimated light towards the tissue, and (ii) a reflector disposed between the light emitter and the light detector, wherein the light from the light emitter is reflected by the reflector in a direction that is laterally away from the light detector and towards the tissue.

A device to determine a biological parameter of a tissue of a person, the device comprising:

• a display;
• a light emitter configured to emit a first light signal and a second light signal towards the tissue;
• a light detector configured to collect a first received signal and a second received signal that are received from the tissue responsive to the first light signal and the second light signal respectively,
• wherein the light emitter is configured to emit the first light signal at a wavelength within the visible light spectrum, and
• wherein the light emitter is configured to emit the second light signal such that the second light signal is inert to changes in blood vessels of the tissue towards which the second light signal is emitted, such that the second received signal carries substantially only noise;
• wherein the device is configured to convert the first received signal and the second received signal to a frequency domain, represented by respective sets of values in multiple frequency bands, wherein a first set of values in multiple frequency bands represents the first received signal and a second set of values in multiple frequency bands represents the second received signal;
• and
• wherein the device is configured to subtract the second set of values in multiple frequency bands from the first set of values in multiple frequency bands in the frequency domain to obtain a third set of frequency bands, wherein the third set of frequency bands represents a third signal corresponding to the biological parameter of the tissue,
• wherein the device further comprises a differential amplifier for amplifying received analog signals received at a photo diode of the light detector, wherein an output of the differential amplifier is responsive to a movement of at least one of the person and the tissue.