Retroreflective lenticular arrays
Retroreflective lenticular systems employing a focusing array and a retroreflector array optically coupled to the focusing array. The focusing array is provided on a first surface and the retroreflector array is provided on an opposing second surface. The retroreflector array includes an array of retroreflective elements alternating with separation areas and disposed in energy exchange relationship with respect to the focusing array. The focusing array includes a plurality of focusing lenses configured to illuminate only the retroreflective elements with focused beams at least at some angles and to focus the incident beam only onto the separation areas at other angles. The intermittent illumination of retroreflective elements provides variable retroreflectivity of at least portions of the system and enhances the system visibility and conspicuity in the reflected light.
1. A retroreflective lenticular system comprising:
a first surface incorporating an array of lenses; and
a second surface extending parallel to said first surface and spaced apart from said first surface by an effective focal distance characterizing said lenses,
wherein at least one region of said second surface comprises a plurality of retroreflective areas spaced apart from each other and alternating with non-retroreflective separation areas according to a predetermined pattern.
2. A retroreflective lenticular system as recited in claim 1 , wherein said lenses have cylindrical configurations and are arranged in parallel columns.
3. A retroreflective lenticular system as recited in claim 1 , wherein said lenses have point-focus configurations and are arranged in rows and columns.
4. A retroreflective lenticular system as recited in claim 1 , wherein said retroreflective areas and said separation areas form a repeating pattern.
5. A retroreflective lenticular system as recited in claim 1 , wherein said predetermined pattern represents two or more different images or patterns interlaced into a single interlaced image or pattern.
6. A retroreflective lenticular system as recited in claim 1 , wherein the pitch of said lenses is a multiple of the pitch of said plurality of retroreflective areas and said multiple is an integer number greater than 1.
7. A retroreflective lenticular system as recited in claim 1 , wherein the transversal width of said retroreflective areas is substantially equal to the width of said separation areas.
8. A retroreflective lenticular system as recited in claim 1 , wherein said region is configured to display one or more dynamic visual effect selected from the group consisting of flashing, color change, flip, animation, morph, and zoom, when said region is viewed through said array of lenses.
9. A retroreflective lenticular system as recited in claim 1 , wherein each of said lenses is selected from the group consisting of imaging lenses, non-imaging lenses, spherical lenses, aspherical lenses, cylindrical lenses, point-focus lenses, Fresnel lenses, TIR lenses, gradient index lenses, and diffraction lenses.
10. A retroreflective lenticular system having a layered structure comprising:
an optical layer having a plurality of light focusing structures;
a retroreflective layer; and
an interlaced optical mask provided between said optical layer and said reflective layer,
wherein said interlaced optical mask comprises a predefined pattern of optically transmissive window areas spaced apart from each other and alternating with separation areas, said separation areas having different optical properties compared to said optically transmissive window areas.
11. A retroreflective lenticular system as recited in claim 10 , wherein said transmissive window areas and said separation areas form a repetitive pattern and the pitch of said plurality of light focusing structures is a multiple of the pitch of said transmissive window areas or said separation areas, and wherein said multiple is an integer number greater than 1.
12. A retroreflective lenticular system as recited in claim 10 , wherein said interlaced optical mask is configured to encode the content of two or more different images, symbols or patterns by means of lenticular interlacing.
13. A retroreflective lenticular system as recited in claim 10 , wherein said interlaced optical mask is configured to display one or more dynamic visual effect selected from the group consisting of flashing, color change, flip, animation, 3D, morph, and zoom.
14. A method of manufacturing an optical article for repetitive displaying surface portions in varying brightness under illumination by a moving distant source of light, said method comprising:
providing a lenticular lens array;
providing a retroreflective layer positioned at a focal distance from said lenticular lens array; and
forming an inverted interlaced mask between said lenticular lens array and said retroreflective layer, said inverted interlaced mask encoding a repetitive sequence of said varying brightness.
15. The method of claim 14 , wherein forming said inverted interlaced mask comprises a process of interlacing of multiple image content into a single interlaced image.
16. The method of claim 14 , wherein forming said inverted interlaced mask comprises a process selected from the group consisting of offset printing, digital printing, and laminating.