Commonwealth Scientific and Industrial Research Organisation

Ccl Secure Pty Ltd

Cll Secure Pty Ltd

Wayne Kevin Jackson

Robert Arthur Lee

Richard Alexander Goodman

Phei Lok

Michael Hardwick

An optically variable device and method of manufacturing the device is disclosed, the device including a plurality of zero-order diffraction grating elements some of which are modulated such that a coloured at least partially polarized image is visible to a person viewing the device, observing a first optically variable effect when the device is rotated about an axis substantially perpendicular to the plane, and a second optically variable effect when the device is viewed under polarized light and rotated about an axis substantially perpendicular to or parallel with the plane. The device is particularly suitable for security documents such as bank notes. Preferably, the first optically variable effect is produced by a change in brightness and/or color of the grating elements and the second optically variable effect may likewise be produced by a change in brightness and/or color of the grating elements. The device advantageously provides two different types of optically variable effect may be provided in a single device. This is possible due to the use of zero-order grating elements as the 'pixels' of the colored image. Each pixel, under illumination by unpolarized light, produces reflected light of a defined color which is also at least partially polarized.

Optically variable device

A hybrid security device for security documents and the like, with the microstructure for a first optically variable device (OVD) and the microstructure for a second OVD mutually interlace or interspersed. The first microstructure has a height profile that differs from that of the second microstructure by more than 0.5 microns. Suitable fabrication processes for the hybrid security device are also disclosed.

Hybrid security device for security document or token

An optical device which generates an optically variable image, the image being optically variable in that it varies according to the position of observation, is manufactured by dividing an optically invariable image into multiple pixels. Color component values are determined for each pixel. For each of the pixels of the optically invariable image, there is determined an associated pixel surface structure which has a three-dimensional surface shape and curvature which is related via a mathematical of computer algorithm to the color component values of the associated pixel in the optically invariable image, each pixel surface structure being an individual reflective or diffractive surface structure which produces an observable optical effect. An assembly of the reflective or diffractive pixel surface structures is produced which when illuminated generates a plurality of observable optical effects which combine to form an optically variable reproduction of the optically invariable image.

Optical device and methods of manufacture

A diffractive device has a surface relief structure which, when illuminated by a light source, generates one or more diffraction images which are observable from particular ranges of viewing angles around the device. The device includes background diffractive structural elements and interstitial diffractive structural elements. The interstitial elements are interspersed between the background elements such that the diffractive action of the background elements is modulated by the interstital elements, with differing interstitial element configuration in differing parts of the surface relief structure producing differing diffraction effects in corresponding parts of the diffraction images.

Diffractive structure with interstitial elements

A pixellated diffractive device includes a multiplicity of pixels ( ) in turn divided into multiple sub-pixels ( ). The device is related to one or more pixellated diffraction surface structures which when illuminated generate respective corresponding optically variable images. The sub-pixels ( ) of each pixel of the diffractive device include diffractive elements ( ) arranged in one or more groups, the diffractive elements of each group matching diffractive elements of a corresponding single pixel of the respective pixellated diffraction surface structures. In each pixel of the device the diffractive elements ( ) of the or each said group are intermixed with other sub-pixels and cooperatively contribute a single element of the corresponding optically variable image which is generated on illumination of the diffractive device.

Multiple image diffractive device

A diffractive device has a surface relief structure which when illuminated by a light source, generates one or more diffraction effects which are observable from a range of viewing angles around the device. At least part of the surface relief structure is arranged in a series of tracks, each track being less than 0.25 mm in width. The device, which may be embossed onto a metallised foil, is suitable for use as an anti-forgery authentication element on valuable documents.

Diffractive device having a surface relief structure which generates two

Diffractive indicia for a surface

Diffractive device for generating one or more diffracting images

An optical data element includes a plurality of diffraction zones wherein each zone contains a multiplicity of diffraction gratings. These zones may be illuminated and the resultant one or more diffracted beams detected to provide a signature for the element consisting of a series of discrete signature signals each generated by the plurality of zones and each including portions or relatively different intensities. At least one of the diffraction zones has a segment thereof modified whereby to discernibly alter at least one of the discrete signature signals of the signature and to thereby form a data segment of the optical data element.

Optical data element including a diffraction zone with a multiplicity of

A diffraction grating providing an optically variable image includes a pixellated diffraction grating in which each pixel is an individual optical diffraction grating so that the pixellated diffraction grating when illuminated generates an optically variable image. In another aspect the grating in some or all of the pixels of a diffracting grating formed by a regular matrix of pixels is arranged such that a reproduction of the grating by reflection contact printing generates a zero-order pattern which is grossly flawed by Moire or Talbot fringe effects. A method of forming the diffraction grating includes producing a counterpart pixellated diffraction grating of a substantially optically invariable image wherein each pixel of the optically invariable image is maped to a respective pixel of the pixellated diffraction grating. Each grating pixel is an individual optical diffraction grating of the associated pixel in the optically invariable image, so that the pixellated diffraction grating when illuminated generates an optically variable reproduction of the optically invariable image.

Growing community of inventors

East Burwood, Australia

Robert Arthur Lee