Vital sign monitoring via touchscreen using bioelectric impedance

Abstract

Methods and apparatus for detecting body vital signs through the use of a Bioelectric Impedance Spectroscopy (BIS), either by (a) direct contact with the person (such as through one or more of their fingers) or (b) measurement of reflections from a field projected into the person's body. The techniques may be implemented using the projected capacitive touch array in a device such as the screen of a smartphone or tablet computer, or the touchpad of a laptop computer.

What is claimed is: 
     
         1 . A method for detecting a body vital sign comprising:
 measuring a bioelectric impedance effect, either by (a) direct impedance measurement via proximity of one or more fingers of the person with components of a projective capacitive touch array; or (b) measurement of reflections from a body resulting from a projected field.   
     
     
         2 . The method of  claim 1  wherein exactly one finger is in physical proximity to the touch array. 
     
     
         3 . The method of  claim 1  wherein two fingers from two different hands of the person are in physical proximity to the touch array. 
     
     
         4 . The method of  claim 1  wherein the touch array is held in the palm of one hand of the person, and the one or more fingers are from the person's other hand 
     
     
         5 . The method of  claim 1  wherein the bioelectric impedance is indicative of heart rate, glucose level, blood pressure, EKG, respiratory rate, drug level, hydration, ulcer, temperature or other vital sign. 
     
     
         6 . The method of  claim 1  wherein a change in impedance is detected using one or more of sensing current versus voltage, phase shifts, resistor-capacitor charge timing, capacitor bridge, charge transfer, successive approximation, sigma-delta modulators, charge accumulation circuits, field-effect, mutual capacitance, or frequency shift.