Tamper-evident device with optically transparent layer and related method

A method of manufacturing a tamper-evident security device, the method comprising:

• providing an optically transparent layer including an array of separate optical focusing elements;
• providing an array of separate image elements collectively defining an image viewable through the optically transparent layer, wherein each of the optical focusing elements is positioned to reveal therethrough a view of one or more of said image element(s);
• and
• providing an optically transparent adhesive layer between the optically transparent layer and the array of separate image elements which retains the optical focusing elements so positioned with respect to the image elements thereby in cooperation to reveal the image,
• wherein the optically transparent adhesive layer is light-sensitive, the method including applying light to the light-sensitive adhesive layer to reduce the adhesive strength of the optically transparent adhesive layer thereby to render the optically transparent layer mechanically separable from the array of separate image elements by release of the optically transparent adhesive layer to cease said cooperation, and wherein the optically transparent adhesive layer remains adhered between the optically transparent layer and the array of separate image elements after applying the light thereto,
• wherein a predetermined sub-portion of the optically transparent adhesive layer or the optically transparent layer is arranged to undergo a visible color change relative to a remainder of the optically transparent adhesive layer or the optically transparent layer when exposed to air as a result of separating the layers of the device, and the predetermined sub-portion is non-detectable before separation, and
• wherein the adhesive strength of the optically transparent adhesive layer renders the optically transparent layer mechanically separable from the array of separate image elements by release of the optically transparent adhesive layer to cease the cooperation.

A tamper-evident security device comprising:

• an optically transparent layer including a first array of separate optical focusing elements;
• a first array of separate image elements collectively defining an image viewable through the optically transparent layer when each of the optical focusing elements is positioned to reveal therethrough a view of one or more of said image element(s);
• an optically transparent adhesive layer between the optically transparent layer and the first array of separate image elements, in which the optically transparent adhesive layer retains the optical focusing elements so positioned with respect to the image elements thereby in cooperation to reveal the image wherein a predetermined sub-portion of the optically transparent adhesive layer or the optically transparent layer is arranged to undergo a visible color change relative to a remainder of the optically transparent adhesive layer or the optically transparent layer when exposed to air as a result of separating the layers of the device, wherein the predetermined sub-portion is non-detectable before separation, the optically transparent layer including:
• a second array of separate optical focusing elements, wherein optical focusing elements of said second array of optical focusing elements are positioned to reveal therethrough a view of one or more of said first array of separate image elements, and
• a second array of separate image elements on an underside surface of a flexible plastic layer of the optically transparent adhesive layer and which collectively define a second image viewable through the optically transparent layer,
• wherein the first array of optical focusing elements are positioned to be non-overlapping with one another with the focusing elements of the second array of optical focusing elements, and
• wherein the optically transparent layer is mechanically separable from the array of separate image elements by release of the optically transparent adhesive layer to cease said cooperation.

A tamper-evident security device comprising:

• an optically transparent layer including an array of separate optical focusing elements;
• an array of separate image elements collectively defining an image viewable through the optically transparent layer when each of the optical focusing elements is positioned to reveal therethrough a view of one or more of said image element(s);
• and
• an optically transparent adhesive layer between the optically transparent layer and the array of separate image elements, in which the optically transparent adhesive layer retains the optical focusing elements so positioned with respect to the image elements thereby in cooperation to reveal the image,
• wherein a predetermined sub-portion of the optically transparent adhesive layer or the optically transparent layer includes an indicator ink arranged to undergo an irreversible visible color change relative to a remainder of the optically transparent adhesive layer or the optically transparent layer when exposed to UV light as a result of separating the first part from the second part, and the predetermined sub-portion is non-detectable before separation, and
• wherein the optically transparent layer is mechanically separable from the array of separate image elements by release of the optically transparent adhesive layer to cease said cooperation.