| 摘要 |
<p>TECHNIQUE FOR VERIFYING GENUINENESS OF AUTHENTICATING DEVICE A given type of authenticating device operates as a diffractive subtractive color filter that exhibits a reflectivity spectrum that includes a peak occurring at a wavelength that varies as a substantially linear function of the angle of incidence of polychromatic illuminating light having a particular polarization. The verification technique involves simultaneously illuminating a sample device over a range of angles of incidence by the polychromatic light, and then employing the light reflected from the sample to illuminate a reference device which is known to be genuine over the same range of angles of incidence. A sample device is indicated as being genuine only if both the respective ratios of the intensity of light reflected from the reference device to the intensity of the illuminating polychromatic light and to the intensity of light reflected from the sample device exceed respective threshold values.</p> |
