| 摘要 |
An improved form of optical security device for use in the protection of documents and articles of value from counterfeit and to verify authenticity is provided. The inventive device, which is made up of an optionally embedded array of icon focusing elements, at least one grayscale in-plane image, and a plurality of coextensive control patterns of icons contained on or within the in-plane image, each control pattern being mapped to areas of the grayscale in-plane image having a range of grayscale levels, provides enhanced design capability, improved visual impact, and greater resistance to manufacturing variations. |
