Cold light UV irradiation device
Assigneearccure technologies GmbH
InventorsMichael Bisges, Knut Kisters
Life of this patent
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Abstract
A cold light UV irradiation device is used for curing UV paint and UV printing dyes on heat-sensitive substrates (12,13). It is used, for example, in plants for printing on packaging foils or in the production line for CD□s (Compact Discs) and DVD□s (Digital Versatile Discs). The irradiation devices used until now emit in addition to the UV radiation also a high portion of heat radiation (IR Radiation) onto the substrate (12,13), which often leads to deformation and brittleness of the substrate. The present invention allows an effective separation of the UV radiation from the IR radiation. With short beam paths, a high UV intensity with a low heat load of the substrate is realized.
Claims36
A device for curing a UV coating (13), on a substrate (12), having at least one light source (5) for generating UV radiation that is located above the substrate (12), a reflector system (2,6,7,17,18) provided to direct the light of said light source to the UV coating (13), and at least one barrier to at least partially prevent the direct beam path of the light source from striking the substrate (12), the improvement comprising:
- a UV reflection coating (2,2d,2f) disposed in a light path between the light source and the barrier to reflect the UV radiation emitted by the light source through the light source to the reflectors (6,7,17,18) located behind the light source;
- at least one heat absorbing body (1,24,25,26,28) associated with the barrier that absorbs, at least partially, the heat radiation emitted by the light source.
A device for optically curing a coating, on a heat-sensitive substrate, comprising:
- a light source, adapted for generating optical and heat radiation, in proximity to the substrate;
- a barrier, disposed along a direct path between the light source and the heat-sensitive substrate, having associated therewith a heat radiation absorbing portion;
- a selective optical radiation reflector, disposed along an indirect path between the light source and substrate, for reflecting optical radiation from and through the light source toward the substrate:
- and
- a distinct selective optical radiation reflective surface, disposed between the light source and the barrier, for reflecting optical radiation from the light source back through the light source toward the optical radiation reflector,
- wherein optical and heat radiation generated by the light source is propagated along a first path to the optical radiation reflective surface, wherein optical radiation is selectively reflected back through the light source, to the selective optical radiation reflector and to the substrate, and heat radiation is at least partially absorbed by the heat radiation absorbing portion, and along a second path from the light source to the selective optical radiation reflector, wherein optical radiation is selectively reflected to the substrate, and at least a portion of the heat radiation is not reflected,
- whereby a ratio of optical radiation to heat radiation is respectively increased between the light source and substrate.
A method for optically curing a coating, on a heat-sensitive substrate, comprising the steps of:
- providing a light source, adapted for generating optical and heat radiation, in proximity to the substrate;
- disposing a barrier along a direct path between the light source and the heat-sensitive substrate, having associated therewith a heat radiation absorbing portion;
- selectively reflecting optical radiation from and through the light source toward the substrate, with a selective optical radiation reflector, disposed along an indirect path between the light source and substrate:
- and
- selectively reflecting optical radiation from the light source back through the light source toward the optical radiation reflector, with a distinct selective optical radiation reflective surface, disposed between the light source and the barrier,
- wherein optical and heat radiation generated by the light source is propagated along a first path to the optical radiation reflective surface, wherein optical radiation is selectively reflected back through the light source, to the selective optical radiation reflector and to the substrate, and heat radiation is at least partially absorbed by the heat radiation absorbing portion, and along a second path from the light source to the selective optical radiation reflector, wherein optical radiation is selectively reflected to the substrate, and at least a portion of the heat radiation is not reflected,
- whereby a ratio of optical radiation to heat radiation is respectively increased between the light source and substrate.
Dependencies are inferred from the claim text.