De La Rue International Limited

Adam Lister

Robert Whiteman

Alice Smith

Lawrence Commander

Brian William Holmes

John Godfrey

Lawrence George Commander

James Peter Snelling

Simon Marchant

A method of manufacturing an image pattern for a security device includes providing a metallised substrate; applying a first photosensitive resist layer to a substrate first metal layer exposing the resist layer to radiation; exposing the resist layer to a first reactant substance; activating a cross linking agent in the resist layer; exposing first and second pattern elements of the resist layer to radiation of a wavelength to which the resist layer is responsive whereupon newly-exposed first pattern elements of the first photosensitive resist layer react, resulting in increased solubility by the second etchant substance, the second pattern elements remaining relatively insoluble by the second etchant substance; and applying first and second etchant substances to the substrate whereupon the first pattern elements of both the first resist layer and the first metal layer are dissolved, the remaining second pattern elements of the first metal layer forming an image pattern.

Security devices and methods of manufacturing image patterns for security devices

A method of manufacturing an image element array for a security device is disclosed. The method comprises: (a) providing a metallised substrate web comprising a substrate having a first metal layer thereon on a first surface of the substrate, the first metal layer being soluble in a first etchant substance; (b) applying a first photosensitive resist layer to the first metal layer; (c) exposing the first photosensitive resist layer to radiation of a wavelength to which the resist layer is responsive through a patterned mask, by conveying the substrate web along a transport path and, during the exposure, moving the patterned mask alongside the substrate web along at least a portion of the transport path at substantially the same speed as the substrate web, such that there is substantially no relative movement between the mask and the substrate web, wherein the patterned mask comprises first pattern elements in which the mask is substantially opaque to the radiation and second pattern elements in which the mask is substantially transparent to the radiation, whereupon the exposed second pattern elements of the first photosensitive resist layer react resulting in increased solubility by a second etchant substance, the non-exposed first pattern elements remaining relatively insoluble by the second etchant substance; and (d) applying the first and second etchant substances to the substrate web whereupon the second pattern elements of both the first resist layer and the first metal layer are dissolved, the remaining first pattern elements of the first metal layer forming an image element array.

Security devices and methods of manufacture thereof

A method of manufacturing a security device includes: a) providing a depth map of a macroimage depicting a three-dimensional object, the depth map representing the depth of each part of the three-dimensional object relative to a reference plane by different colours and/or different tones of one colour; b) segmenting the depth map into a plurality of regions based on the colours and/or tones of the depth map; c) for each region, creating a respective microimage element array; and d) providing a sampling element array of a predetermined pitch and orientation. The pitch and/or orientation of each respective microimage element array is different, and is configured such that the magnified versions of the microimage elements generated in any one of the regions have a different apparent depth relative to those generated in the other region(s), so as to form a three-dimensional representation of the macroimage.

Methods of manufacturing a security device

A method of making a security device, comprising: forming an array of primary focusing elements on a first region of a focusing element support layer, by applying at least one transparent curable material either to the focusing element support layer or to a casting tool carrying a surface relief over an area which includes at least the first region, the surface relief comprising portions corresponding to the primary focusing elements; forming the transparent curable material(s) with the casting tool; and curing the transparent curable material(s) so as to retain the surface relief in the first region; wherein the surface relief further includes a plurality of structures of greater depth than the height of the primary focusing elements such that the cured transparent material(s) include a plurality of features protruding above the height of the primary focusing elements between primary focusing elements of the array.

Methods of manufacturing security documents and security devices

A security device is provided. The security device comprises an array of elongate focusing structures, the elongate axes of which are aligned along a first direction, the elongate focusing structures being arranged parallel to one another periodically along a second direction which is orthogonal to the first direction, each elongate focusing structure having an optical footprint of which different elongate strips will be directed to the viewer in dependence on the viewing angle, the centre line of each optical footprint being parallel with the first direction. An array of image elements overlap the array of elongate focusing structures, the array of image elements representing elongate image slices of at least two respective images, each image slice comprising one or more image elements, and at least one image slice of each respective image being located at least partially in the optical footprint of each elongate focusing structure. The array of image elements is configured such that the pitch between the elongate image slices of each respective image in the second direction varies across the array in the first and/or second direction(s). At any one viewing angle, in a first region of the device the elongate focussing structures direct portions of first image slices corresponding to a first image to the viewer such that the first image is displayed across the first region of the device, and simultaneously, in a second region of the device which is laterally offset from the first region in the first and/or second direction(s), the elongate focussing structures direct portions of second image slices corresponding to a second image to the viewer such that the second image is displayed across the second region of the device, the positions of the first and second regions relative to the security device depending on the viewing angle.

Security device and method of manufacture

A security device is provided including a first pattern of elements and a second, overlapping, pattern of elements spaced by a transparent layer, the first and second patterns in combination obstructing the passage of light transmitted to a viewer through the device to a varying degree depending on the viewing position. The first and second patterns of elements are configured such that a first region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a first tilt axis, and a second region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a second tilt axis which is not parallel to the first tilt axis.

Security devices

A method of manufacturing an image element array includes: providing a production tool having a surface pattern of ink-receptive elements spaced by areas which are not, the ink-receptive elements defining the array image elements; applying a multi-colored first image formed of a inks to only the ink-receptive elements; and transferring only the portions of the multi-colored first image corresponding to the image elements from the production tool to a substrate. An image element array is formed on the substrate. The production tool surface pattern is configured such that when viewing and image element arrays overlap, each viewing element within an image element array first region directs light from a respective image element or from a respective gap. The viewing angle in the first region directs light from either the array or the gaps.

Methods of manufacturing image element arrays for security devices

A method of manufacturing a security device including: conveying a substrate web including a photosensitive film along a transport path; exposing the photosensitive film to radiation of a predetermined wavelength through a mask, wherein the mask includes a predetermined pattern of regions which are substantially opaque to radiation of the predetermined wavelength and at least semi-transparent to radiation of the predetermined wavelength, respectively; during the exposure, moving the mask alongside the substrate web along at least a portion of the transport path at substantially the same speed as the substrate web, such that there is substantially no relative movement between the mask and the substrate web; and heating the substrate web including the exposed photosensitive film. In this way, regions of the photosensitive film exposed to the radiation of the predetermined wavelength undergo an increase in optical density such that the photosensitive film displays a reproduction of the predetermined pattern.

A method and security device, including: a semi-transparent layer exhibiting a first pattern of regions having high optical density and/or raised surface profile relative to layer intervening regions; and a color layer exhibiting a second pattern of elements of at least one color. First and second patterns partially overlap and are configured so the device, appearance varies at different viewing angles. First pattern has color layer following the contours of raised regions. Security device includes: a photosensitive film exhibiting pattern of regions of relatively high and low optical density, the pattern arising from photosensitive film exposure to radiation of a responsive predetermined wavelength from the photosensitive film; and a color layer overlapping the pattern exhibited by photosensitive film, which exhibits increase in optical density upon radiation exposure of a predetermined wavelength and concurrent or subsequent heating. Increases in optical density being due to the bubbles formation within the photosensitive film.

The present invention relates to improvements in security devices that can be used in various authenticating or security applications, and in particular to an optically variable security device which can be viewed under low light conditions. The security device comprises a light deflection structure having a first side and a second opposing side. A colorshifting layer is applied to the first side of the light deflection structure and a reflection layer is applied to at least a first region of the second side of the light deflection structure so as to provide a strong reflection in a direction substantially parallel to the incident light source when the direction of the incident light is at an angle away from the normal to the security device. The security device has at least one second region in which the reflection layer is absent, said first and second regions defining indicia.

Improvements in security devices are provided that are used for authenticating or security applications. The security device includes a first color-shifting layer and a second color-shifting layer, which exhibits different reflective characteristics to the first color-shifting layer. A partial first light absorbing layer is between first surfaces of the first and second color-shifting layers and a second light absorbing layer applied to a second surface of the second color-shifting layer. The color of the partial first absorbing layer is selected to substantially match the color of light reflected at a normal angle of incidence by the combination of the second color-shifting layer and the second absorbing layer.

The present invention relates to improvements in security devices that can be used in varying shapes and sizes for various authenticating or security applications, and in particular to an optically variable security device utilizing colorshift materials. The security device () comprises a first and a second layer (, lib) of a colorshifting material at least partially overlying each other and each having different colorshifting properties. At least partially applied over surface of one of the colorshifting layers is a light control layer () having a surface structure which modifies the angle of reflected light, such that light reflected by the security device is seen at a different viewing angle.

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Andover, United Kingdom

Adam Lister