Method and system for forming RF reflective pathways

#1. Field of the Invention

#The present invention relates to a system and method for forming RF reflective pathways. In particular, the system and method is for making variably printed radio frequency antennas for radio frequency tags.

#2. Description of the Background Art

#The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

#FIG. 1 is a schematic side view of a first system for forming RF reflective pathways of the present invention; and

#FIG. 2 is a schematic side view of a second system for forming RF reflective pathways of the present invention.

#Referring in detail to the drawings and with particular reference to FIG. 1, a first system 10 for forming RF reflective pathways is shown. While the specification will discuss RF reflective pathways, it should be noted that these pathways will also be electrically conductive. This system 10 includes a conveyor 12 for infeeding a thermal transfer ribbon 14 and a received substrate 16. This conveyor 12 is only schematically shown in FIG. 1 as a pair of feed rolls. It should be appreciated that any type of conveyor system could be utilized. For example, a belt conveyor, chain conveyor, series of rollers, or any other known conveyor system could be used. Moreover, while only a pair of rollers 12 are shown, it should be contemplated that a continuous conveyor can be used over the length of the system 10 or any suitable number of conveyor units can be incorporated into the conveyor system.

#The thermal transfer ribbon 14 and receiver substrate 16 are fed past a heat source or thermal print head 18. The thermal print head 18 will selectively heat portions of the thermal transfer ribbon 14 to ultimately form a desired pattern on the receiver 16, as will be discussed below. While such a thermal print head 18 is known, its use in a method for forming RF reflective pathways is new. In addition, a backing roller 20 is provided to support the thermal transfer ribbon 14 and receiver substrate 16. While a backing roller 20 is shown, it should be noted that other support surfaces could be used. For example, a flat supporting table or other structure could be opposed to the print head 18.

#The thermal transfer ribbon 14 has a reactive coating or a conductive transferable material thereon. When this reactive coating or material is heated by the thermal print head 18, a RF reflective pathway can be printed on the receiver substrate 16. Thermal transfer ribbon 14 either has a conductive material or RF reflective material or a material that becomes conductive or RF reflective upon the application of heat. The heat from print head 18 will serve to transfer the material to receiver substrate 16 and in some instances will also serve to activate the material to make it conductive or RF reflective. In those circumstances, the transferred composition will be a RF reflective precursor.