Radiant energy – Luminophor irradiation
Reexamination Certificate
1999-05-14
2001-08-14
Hannaher, Constantine (Department: 2878)
Radiant energy
Luminophor irradiation
C250S271000, C250S459100
Reexamination Certificate
active
06274873
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to authentication marks or security marks and, more particularly, a device and method for reading an authentication mark by analyzing the spectrum of visible light that is emitted by the authentication mark when the authentication mark is illuminated with infrared and/or ultraviolet light.
2. Description of the Related Art
Various techniques have been used to identify articles in an effort to reduce counterfeiting. For collectibles such as art works and sports memorabilia, where a single item may be worth millions of dollars, a technique that is highly refined and virtually impossible to copy is desired. This is because high potential counterfeiting gains will motivate counterfeiters to invest large sums of money and resources to defeat the anti-counterfeit measure. Similarly, the high cost of implementing an anti-counterfeit measure for collectibles is typically accepted by the owner or insurer, because the potential loss from counterfeiting is great.
On the other hand, for mass produced items such as apparel, CDs, and audio and video cassettes, cost is a more important factor in implementing an anti-counterfeit measure. The implementation cost must be small enough so that the cost of the protected product will not increase dramatically. Yet, the anti-counterfeit measure must be refined enough so that counterfeiters will be unable to defeat the anti-counterfeit measure in a sufficiently easy manner such that they will be able to economically produce and sell counterfeit goods.
Mass produced items also have to be protected against product diversion. Product diversion occurs when a counterfeiter acquires genuine, non-counterfeit goods that are targeted for one market and sells them in a different market. The counterfeiter does this to circumvent the manufacturer's goal of controlling the supply of his or her goods in a particular market and, as a consequence, benefits from the sales in that limited supply market or in the diverted sales market.
In one type of anti-counterfeit and anti-diversion measure, an ultraviolet (UV) ink is used to mark the product with an identifying indicia. One benefit of using the UV ink is that it is typically not visible when illuminated with light in the visible spectrum (380-770 nm), but is visible when illuminated with light in the UV spectrum (200-380 nm). Therefore, counterfeiters will be unable to tell whether the product contains a security mark by merely looking at the product when the product is illuminated with visible light.
A number of UV inks are readily available in the security industry and can be obtained at a relatively low cost. Several UV ink types and compositions are described, for example, in U.S. Pat. No. 5,569,317, entitled “Fluorescent and Phosphorescent Tagged Ink for Indicia” the disclosure of which is incorporated by reference herein. This patent discloses a security mark that becomes visible when illuminated with UV light having a wavelength of 254 nm.
However, the use of security marks containing a UV ink has seen increased use and counterfeiters have become knowledgeable about their use. It has been a common practice for counterfeiters to examine the UV ink from a product sample, reproduce or procure the same or similar UV ink that matches the characteristics of the UV ink from the product sample, and apply the same security mark on the counterfeit products using the substitute UV ink.
In another type of anti-counterfeit and anti-diversion measure, an infrared (IR) ink is used to mark the product with an identifying indicia. As with the UV ink, one benefit of using the IR ink is that it is typically not visible when illuminated with light in the visible spectrum, but is visible when illuminated with light in the IR spectrum (800-1600 nm). An additional benefit of using the IR ink is that it is more difficult to reproduce or procure the matching IR ink by studying a product sample containing the IR security mark. Examples of IR security mark usage are given in U.S. Pat. No. 5,611,958 and U.S. Pat. No. 5,766,324. The disclosures of these patents are incorporated by reference herein.
Combination security marks have also been proposed. In U.S. Pat. No. 5,360,628 and U.S. Pat. No. 5,599,578, the disclosures of both of which are incorporated by reference herein, a security mark comprising a visible component and an invisible component made up of a combination of a UV dye and a biologic marker, or a combination of an IR dye and a biologic marker is proposed. Also, in U.S. Pat. No. 5,698,397, the disclosure of which is incorporated by reference herein, a security mark containing two different types of up-converting phosphors is proposed.
The detection of invisible security marks is performed automatically using a photodiode, for example, or manually by observing the fluorescence that results from illumination with a UV or IR light source. Sometimes, an invisible security mark is printed as an invisible bar code, as in U.S. Pat. No. 5,502,304, U.S. Pat. No. 5,525,798, U.S. Pat. No. 5,542,971, and U.S. Pat. No. 5,766,324, and is read using a bar code reader. However, there has been no system for automatically determining the characteristics of light that is emitted from an invisible security mark as a result of illumination with a UV or an IR light source. For example, an IR ink may emit a green light in response to illumination with IR light, but the automatic reading systems described above merely look for any emission above a certain threshold and do not distinguish between a green light emission and any other spectral characteristic.
SUMMARY OF THE INVENTION
An object of this invention is to provide a system and method for determining the light emission characteristics of an authentication mark that is invisible when illuminated with visible light but is visible when illuminated with either UV or IR light. As used herein, an “invisible” mark is a mark that is not visible with the human eye when illuminated with light in the visible spectrum.
The above and other objects of the invention are achieved by a spectrum analyzer having an IR light source, a mirror positioned to deflect light from the IR light source in a direction that is substantially perpendicular to a surface of the authentication mark, a first lens for collimating light that is emitted by the authentication mark in response to an illumination by the light from the IR light source, an optical element comprising a prism or a hologram for generating a spectrum from the collimated light, a second lens for imaging the spectrum, an IR light blocking filter, a detector positioned to receive light components of the spectrum after the spectrum has been imaged by the second lens and filtered by the IR light blocking filter, and a control unit connected to the detector and programmed to read the authentication mark based on intensities of the light components received by the detector.
The detector comprises an array of photodiodes or charged-coupled devices (CCDs) each positioned to receive a different one of the imaged light components. Alternatively, a single aperture-photodiode assembly may be used. When the single aperture-photodiode assembly is used, the assembly can be controlled to be moved to a plurality of positions so that the photodiode receives a different one of the imaged light components through the aperture at each of the plurality of positions of the assembly or the optical element can be controlled to be rotated to a plurality of positions such that the photodiode receives a different one of the light component through the aperture at each of the plurality of positions of the optical element.
The spectrum analyzer according to the invention may further comprise a beam splitter positioned between the object lens and the prism, a reticle positioned to image light deflected by the beam splitter, and a movable stage on which the authentication mark is mounted. The movable stage can be controlled in accordance with the image formed by the reticle to align the authentica
Helmick Mark
Outwater Chris
DNA Technologies Inc.
Foley & Lardner
Hannaher Constantine
LandOfFree
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