Apparatus for embossing a flexible substrate with a pattern carried by an optically transparent compliant media
View Patent ↗An apparatus for embossing a flexible substrate with an optically transparent compliant media is disclosed. The complaint media includes an optically transparent imprint stamp with an imprint pattern therein. The flexible substrate is coated with a photopolymer material. The compliant media can be connected with an optically transparent belt material to form an embossing belt or connected with an optically transparent cylinder to from an embossing drum. A coated side of the flexible substrate is urged into contact with the imprint stamp and the imprint pattern is embossed in the photopolymer material and an ultraviolet light passing through the compliant media contemporaneously cures the photopolymer material during the embossing.
1. An embossing apparatus, comprising:
a flexible substrate including a coated side and a base side;
a coating unit for depositing a photopolymer material having a first thickness on the coated side;
an embossing belt comprising an optically transparent belt material and an optically transparent compliant media connected with the belt material, the compliant media including an optically transparent imprint stamp having an imprint pattern therein;
a plurality of transport rollers connected with the belt material and operative to support the embossing belt;
a drive unit for imparting a drive motion to the embossing belt and the flexible substrate;
a backing drum wrapped by a portion of the base side and by a portion of the compliant media so that a tension is imparted in the embossing belt and the tension generates a pressure between the flexible substrate and the embossing belt,
the drive motion is operative to transport the base side over the backing drum and to urge the imprint stamp and the coated side into contact with each other so that the imprint pattern is embossed in the photopolymer material and forms a replicate pattern in the photopolymer material; and
an ultraviolet light source for irradiating the replicate pattern with an ultraviolet light, the ultraviolet light source is positioned so that the ultraviolet light first passes through the optically transparent belt material, then passes through the optically transparent compliant media, and finally passes through the optically transparent imprint stamp to irradiate the replicate pattern in the photopolymer material, and the ultraviolet light source is positioned so that the irradiating occurs contemporaneously with the embossing of the replicate pattern in the photopolymer material.
2. The embossing apparatus as set forth in claim 1 , wherein the flexible substrate is opaque to the ultraviolet light.
3. The embossing apparatus as set forth in claim 1 , wherein the ultraviolet light source has a position relative to the embossing belt selected from the group consisting of a position inside of the embossing belt and a position outside of the embossing belt.
4. The embossing apparatus as set forth in claim 1 , wherein the ultraviolet light source comprises a UVA ultraviolet light source.
5. The embossing apparatus as set forth in claim 1 , wherein the ultraviolet light includes a wavelength from about 300.0 nanometers to about 400.0 nanometers.
6. The embossing apparatus as set forth in claim 1 , wherein the coating unit comprises a coater selected from the group consisting of a Gravure Coater, a micro gravure coater, and a Slot Die coater.
7. The embossing apparatus as set forth in claim 1 , wherein the first thickness of the photopolymer material is in a range from about 0.05 micrometers to about 2.0 micrometers.
8. The embossing apparatus as set forth in claim 1 , wherein at least one of the transport rollers is connected with the drive unit and the drive unit is operative to rotate the transport roller to impart the drive motion to the embossing belt and the flexible substrate.
9. The embossing apparatus as set forth in claim 1 and further comprising:
a supply reel for carrying the flexible substrate and for dispensing the flexible substrate to the coating unit.
10. The embossing apparatus as set forth in claim 1 and further comprising:
a takeup reel for collecting the flexible substrate after the flexible substrate has been embossed and cured.
11. The embossing apparatus as set forth in claim 10 , wherein the takeup reel is connected with the drive unit and the drive unit is operative to rotate the takeup reel to collect the flexible substrate and to impart the drive motion.
12. The embossing apparatus as set forth in claim 1 , wherein the compliant media comprises an optically transparent silicone-based elastomer material that is laminated to an optically transparent transfer adhesive layer.
13. The embossing apparatus as set forth in claim 12 , wherein the optically transparent silicone-based elastomer material is a material selected from the group consisting of polydimethyl siloxane and a silicone-based conformal coating.
14. The embossing apparatus as set forth in claim 12 , wherein the optically transparent transfer adhesive layer is an optically clear silicone adhesive.
15. The embossing apparatus as set forth in claim 1 , wherein the optically transparent belt material comprises a Polyester film.
16. The embossing apparatus as set forth in claim 1 , wherein the ultraviolet light source further includes a reflector for focusing the ultraviolet light at a point where the imprint stamp is urged into contact with the coated side so that the photopolymer material is not cured before the imprint pattern is embossed in the photopolymer material.