Selective metal removal process for metallized retro-reflective and holographic films and radio frequency devices made therewith

Abstract

A method for selectively removing metal from a metallized substrate (e.g., a metallized polymer film) and the formation of devices thereby are provided. The method involves selectively exposing the metallized surface to a demetallizing (i.e., an oxidizing) chemical solution. The metallized layer can be selectively exposed to the demetallizing solution using a flexographic printing process wherein printing rollers are used to transfer the demetallizing solution to the metallized surface. An identification device including, for example, a holographic, retro-reflective, or other metallized material and a radio-frequency transponder are also provided. The radio-frequency transponder includes an RF chip and an antenna in electrical communication with the chip. The identification device including the holographic image allows both electronic identification through the reading of identification data stored in the chip and optical identification via the holographic image.

Description

RELATED APPLICATION INFORMATION [0001] This application is a continuation application of U.S. patent application Ser. No. 10 / 118,092 filed on Apr. 9, 2002 including the specification, claims, drawings and summary. The disclosure of the above patent applications is incorporated herein by reference in its entirety.FIELD OF THE INVENTION [0002] The present invention relates generally to a process for selectively removing metallic material from a metallized film and, in particular, to the removal of metallic material from a metallized polymeric film using a printing method such as flexographic printing. The film can be a reflective film (e.g., a retro-reflective film) or a holographic film that can be used, for example, in an identification device comprising a radio frequency (RF) transponder. BACKGROUND OF THE TECHNOLOGY [0003] Retro-reflective materials can reflect and re-emit incident light in a direction that is parallel to that of the source of the incident light. In other words, r...

AI Technical Summary

Benefits of technology

[0009] According to a third aspect of the invention, a method of making an identification device comprising a base layer and at least one metal region disposed thereon is provided. The method comprises: selectively demetallizing a first metal region of the device; forming a holographic image in the first metal region; forming an antenna on the base layer; and mounting an RF chip on the base layer in electrical communication with the antenna to form an RF transponder. According to this aspect of the invention, the selective demetallization of the first metal region allows the RF transponder to transmit and receive information.

Problems solved by technology

It is known that metal blocks the transmission and reception of radio frequency (RF) signals because the RF signal is absorbed or distorted by the metal content in the material.

As a result, the signal cannot be received by an antenna blocked by metal.

Such a blocked signal cannot be used, for example, to activate a connected device.

This same blocking effect can occur whether the device is positioned on top of or underneath the metallic material because the distortion and absorption of the RF signal will be affected in either case.

Thus, there is a problem in the prior art with regard to using retro-reflective and holographic materials, as well as other materials containing metals, on the surface of devices for receiving RF signals.

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