SECURITY DEVICES AND METHODS OF MANUFACTURE

摘要

A security device has: an array of focusing elements on a grid; and an array of image elements overlapping the focusing elements array and arranged based on a repeating unit cell defining image element positions. The unit cell periodicity is substantially the same as the grid's. Each position is assigned to carry an image element of a respective corresponding image. Dependent on angle, the focusing elements array directs light from selected positions, as the device is tilted different ones of the respective images are displayed by the elements at the selected positions in combination, sequentially. Each unit cell centre area, larger than each outer area, is assigned to carry element(s) of a corresponding centre image, the outer areas assigned to carry element(s) of other respective images, such that the range of viewing angles over which the centre image is displayed is greater than that over which each other image is.

主权项

1. A security device, comprising:
an array of focusing elements, each focusing element being adapted to focus light in at least a first direction, the focusing elements being arranged on a regular grid in at least one dimension; and
an array of image elements overlapping the array of focusing elements, the image elements being arranged based on a repeating unit cell defining image element positions, the periodicity of the unit cells being substantially the same as that of the grid on which the array of focusing elements is arranged, the unit cell defining a set of image element positions therewithin, each image element position within the unit cell being assigned to carry an image element of a respective corresponding image;whereby, depending on the viewing angle, the array of focusing elements directs light from selected image element positions to the viewer, such that as the device is tilted different ones of the respective images are displayed by the image elements at the selected image element positions in combination, sequentially;wherein a centre area of each unit cell, comprising one or more image element positions, is assigned to carry image element(s) of a corresponding centre image, the centre area being larger than each outer area of the unit cell, the outer areas being located outside the centre area and assigned to carry image element(s) of other respective images, such that the range of viewing angles over which the centre image is displayed to a viewer is greater than the range of viewing angles over which each other image is displayed.