Patient monitoring system employing array of force sensors on a bedsheet or similar substrate

A sensing sheet for use in a patient monitoring system, the patient monitoring system including processing apparatus operative to calculate a spatially weighted sum of the respective values of sensor signals generated by the sensing sheet, the spatially weighted sum being calculated using a set of predetermined two-dimensional spatial weight values, the sensing sheet comprising:

• a first electrically insulative film, the first film having length and width substantially corresponding to the length and width of a patient's bed and having a pattern of conductive electrodes formed thereon, the conductive electrodes being spaced apart on the film to define a two-dimensional sensing area extending substantially entirely across the patient's bed when the sensing sheet is placed thereon, the conductive electrodes having respective sizes, shapes and locations in relation to the predetermined two-dimensional spatial weight values such that the spatially weighted sum accurately reflects the spatial distribution of forces existing between a patient and the patient's bed when the sensing sheet is disposed therebetween, the first film also including a set of conductive traces creating individual conductive paths from the electrodes to a connection area of the sensing sheet;
• a second electrically insulative film laminated with the first film, the second film having length and width substantially the same as the length and width of the first film, the second film having a pattern of conductive electrodes formed thereon at respective locations directly opposite the respective locations of the electrodes on the first film, the second film also including conductive traces operative to electrically interconnect all of the conductive electrodes on the second film to each other and to the connection area of the sensing sheet;
• and
• a multi-conductor cable extending from the connection area of the sensing sheet and including a multi-terminal connector, the conductors of the cable being operative to create respective conductive paths from respective conductive traces of the first and second films to respective terminals of the multi-terminal connector.