| 摘要 |
An optical element comprises at least one specially prepared substrate containing at least one holographic device applied or incorporated in the substrate thus producing a holographic interference pattern capable of producing an image and means whereby the application of light rays or heat falling on the device initiate or confirm a change in the substrate or the holographic device or both so as to alter the holographic image. The element can be incorporated into a bottle closure or other such container to provide tamper indication. A second holographic device may act as a magnifying optical element for a first hologram. <IMAGE> |
