Wearable device for sensing vital signs

A wearable device for sensing vital signs comprising:

• a housing defining an interior cavity;
• an optical unit positioned inside the interior cavity, the optical unit having:
• one or more light emitters that emit optical signals;
• a first polarizer orientated to polarize the optical signals emitted from the one or more light emitters in a first polarity direction;
• a second polarizer orientated with respect to the second polarizer to block optical signals reflected in the first polarity direction;
• and
• one or more light sensors that receive reflected optical signals that pass through the second polarizer, the reflected optical signals being used to non-invasively measure peripheral oxygen saturation.

A method for obtaining vital signs, comprising:

• emitting polarized optical signals;
• filtering optical signals that do not penetrate into a tissue;
• receiving the filtered optical signals;
• and
• using the filtered optical signals to measure a vital sign.