1. An optically variable device comprising a substrate having an array of structures formed thereon, therein or supported thereby, wherein said structures are coated with an optically variable color-shifting coating, wherein the each of the structures form a pyramidal structure and wherein each pyramidal structure has at least three slanted faces and wherein more than one color is seen when viewing the pyramids vary as substrate is rotated at least 30 degrees about an axis orthogonal to the substrate.
2. An optically variable device as defined in claim 1, where the dimensions of the pyramids are below eye resolution.
3. An optically variable device as defined in claim 1, where the dimensions of the pyramids are less than 100 microns.
4. An optically variable device as defined in claim 1, wherein spaces or structures that differ from the array of structures are provided between said array of structures so as to form visible indicia, sized discernable without magnification.
5. An optically variable device as defined in claim 1, having visible indicia formed therein distinguishable from the array of pyramidal structures.
6. An optically variable device as defined in claim 2, wherein the height to base ratio of at least 50% of the pyramidal structures is in the range of 0.4 to 1.4.
7. An optically variable device as defined in claim 2, wherein a first plurality of the pyramidal structures are oriented in a first predetermined orientation and wherein a second plurality of the pyramidal structures are oriented in a second different orientation so that the first plurality of structures appear to be a different color than the second plurality of structures.
8. An optically variable device as defined in claim 1, wherein a first group of contiguous pyramidal structures differs from a second group of contiguous pyramidal structures and wherein of the first and second groups forms visually distinguishable indicia.
9. An optically variable device as defined in claim 1, wherein the slope of each of the faces of a pyramidal structure forms a different angle with the substrate.
10. An optically variable device as defined in claim 1, wherein the slope of each the faces of a pyramidal structure forms a same angle with the substrate.
11. An optically variable device as defined in claim 2, wherein the plurality of structures form an array of pyramidal structures and wherein the thickness of the optically variable coating on each of the faces is a same substantially uniform thickness.
12. An optically variable device as defined in claim 2, wherein the thickness of the optically variable coating on adjacent faces of the pyramid is a different thickness.
13. An optically variable device as defined in claim 1, wherein the coating is a single cavity Fabry-Perot structure.
14. An optically variable device as defined in claim 1, wherein the coating is a multi-cavity Fabry-Perot structure.
15. An optically variable device as defined in claim 1, wherein a plurality of pyramids are at least one of tetrahedron pyramids, square pyramids, pentagonal pyramid and a frustum pyramids with flat tops.
16. An optically variable device as defined in claim 15, wherein at least one of the faces on at least a plurality of the pyramids have a diffraction grating formed therein.
17. A method of providing a device that exhibits color by rotation comprising:
a) providing a substrate having an array of small pyramidal or inverted pyramidal structures formed therein or thereon wherein the pyramidal structures are sized so that they can only be discerned with the human eye with the aid of magnification; and,
b) coating the pyramidal or inverted pyramidal structures with a multi-layer color shifting coating.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. Apparatus for treating a wafer-shaped article, comprising:
a spin chuck for holding a wafer-shaped article in a predetermined orientation wherein a lower surface of the wafer-shaped article is spaced a predetermined distance from an upper surface of the spin chuck;
at least one infrared heater mounted above said upper surface of said spin chuck and underlying a wafer-shaped article when mounted on the spin chuck, said at least one infrared heater being stationary in relation to rotation of said spin chuck; and
a plate that is transparent to infrared radiation emitted by said at least one infrared heater, said plate being mounted for rotation with said spin chuck and being positioned between said at least one infrared heater and a wafer-shaped article when positioned on said spin chuck.
2. The apparatus according to claim 1, wherein said plate is part of a housing that surrounds said at least one infrared heater, said housing being mounted for rotation with said spin chuck.
3. The apparatus according to claim 2, wherein said housing comprises a lower shell surrounding said at least one infrared heater and positioned between said at least one infrared heater and said upper surface of said spin chuck, said lower shell having a reflective interior surface.
4. The apparatus according to claim 1, wherein said spin chuck comprises a rotatable chuck body surrounding a central stationary post, and wherein said at least one infrared heater is mounted to an upper end of said central stationary post.
5. The apparatus according to claim 1, wherein said at least one infrared heater is part of a heating assembly comprising at least two independently controllable infrared heating elements.
6. The apparatus according to claim 2, wherein said housing is centered on an axis of rotation of said spin chuck, and wherein said spin chuck comprises a circular series of pins configured to contact an edge of a wafer-shaped article in a closed position, said pins passing through a corresponding series of openings formed in a periphery of said housing.
7. The apparatus according to claim 5, wherein each of said independently controllable heating elements comprises at least one curved portion.
8. The apparatus according to claim 1, further comprising a lower shell surrounding said at least one infrared heater and positioned between said at least one infrared heater and said upper surface of said spin chuck, said lower shell having a reflective interior surface and being stationary in relation to rotation of said spin chuck.
9. The apparatus according to claim 1, wherein said at least one infrared heater is part of a heating assembly comprising at least three independently controllable infrared heating elements.
10. An infrared heating assembly for use in an apparatus for treating a wafer-shaped article, said infrared heating assembly comprising:
a housing comprising an upper plate that is transparent to infrared radiation emitted by said infrared heating assembly, and a lower shell having a reflective interior surface;
a plurality of infrared heating elements mounted on a common frame positioned within said housing, said common frame comprising a connector portion projecting downwardly through a central opening in said lower shell; and
a rotary bearing positioned outside of said connector portion and inside of said central opening, thereby to permit rotation of said housing relative to said common frame and said plurality of infrared heating elements;
wherein said housing is rotatable relative to said common frame and said plurality of infrared heating elements about an axis that is perpendicular to said upper plate.
11. The infrared heating assembly according to claim 10, wherein each of said infrared heating elements is independently controllable and comprises at least one curved portion.
12. The infrared heating assembly according to claim 11, wherein the curved portions of adjacent infrared heating elements extend along concentric circles.
13. The infrared heating assembly according to claim 10, wherein said connector portion comprises a plurality of electrical connectors equal in number to said plurality of infrared heating elements, thereby to permit individual connection of each of said plurality of infrared heating elements to a controller for individually energizing each of said plurality of infrared heating elements.
14. The infrared heating assembly according to claim 10, wherein each of said infrared heating elements comprises at least one curved portion, and wherein said at least one curved portion of each of said infrared heating elements extends along an arc of a circle whose center is offset from said axis.
15. The infrared heating assembly according to claim 10, wherein said housing comprises a circular series of peripheral openings to permit passage of gripping pins when said infrared heating assembly is mounted to a spin chuck.
16. An infrared heating assembly for use in an apparatus for treating a wafer-shaped article, said infrared heating assembly comprising:
a housing comprising an upper plate that is transparent to infrared radiation emitted by said infrared heating assembly, and a lower shell having a reflective interior surface, said housing comprising a circular series of peripheral openings to permit passage of gripping pins when said infrared heating assembly is mounted to a spin chuck;
a plurality of infrared heating elements mounted on a common frame positioned within said housing, said common frame comprising a connector portion projecting downwardly through a central opening in said lower shell; and
a rotary bearing positioned outside of said connector portion and inside of said central opening, thereby to permit rotation of said housing relative to said common frame and said plurality of infrared heating elements.
17. The infrared heating assembly according to claim 16, wherein each of said infrared heating elements is independently controllable and comprises at least one curved portion.
18. The infrared heating assembly according to claim 16, wherein said connector portion comprises a plurality of electrical connectors equal in number to said plurality of infrared heating elements, thereby to permit individual connection of each of said plurality of infrared heating elements to a controller for individually energizing each of said plurality of infrared heating elements.
19. The infrared heating assembly according to claim 16, wherein said housing is rotatable relative to said common frame and said plurality of infrared heating elements about an axis that is perpendicular to said upper plate.
20. The infrared heating assembly according to claim 19, wherein each of said infrared heating elements comprises at least one curved portion, and wherein said at least one curved portion of each of said infrared heating elements extends along an arc of a circle whose center is offset from said axis.