The dot matrix hologram (DMH) has been widely used in anti-counterfeiting label. With the same technology and cell array configuration, we can encode to the incidence beam. These codes can be some image matrix grating with different grating gap and different grating orientation. When the multi-level phase diffractive grating is etched, the incidence beam on the cell appears as an encoding image. When the encoded grating and DMH are used in the same label synchronously, the technology of multi-encoded grating array enhances the anti-counterfeit ability.
© 2005 Chinese Optics Letters
Zhongyu Chen, N. K. Bao, and Po S. Chung, "Encoded cell grating array in anti-counterfeit technology," Chin. Opt. Lett. 3, 319-321 (2005)