US Patent 8072594 Liquid level sensor

A liquid level sensor probe for determining liquid level within a vessel, the liquid level sensor probe comprising at least one light source positioned for emitting radiant energy; at least one photosensor positioned for detecting an amount of radiant energy received from at least one light source wherein a change in the amount of radiant energy as detected by at least one photosensor is indicative of a change in liquid level within the vessel; at least one light shield positioned between at least one light source and at least one photosensor wherein at least one light shield prevents radiant energy from directly hitting at least one photosensor; and encapsulation material.