REPLICATION TOOL

Abstract

The present invention relates to a replication tool for replicating an element from a replication material, the replication tool comprising a replication side, a plurality of cavities on the replication side, each defining the shape of one element or a group of elements, the replication tool further comprising at least one bump portion, protruding, on the replication side, from the cavities, and further comprising means for confining the replication material to a predetermined area of the tool, when the tool is pressed against a substrate, which predetermined area exceeds the desired volume of the element in at least one direction along the surface of the substrate.

Claims

1. A replication tool for replicating an element from a replication material, the replication tool comprising a replication side, a plurality of cavities on the replication side, each defining the shape of one element or a group of elements, the replication tool further comprising at least one bump portion, protruding, on the replication side, from the cavities, and further comprising means for confining the replication material to a predetermined area of the tool, when the tool is pressed against a substrate, which predetermined area exceeds the desired volume of the element in at least one direction along the surface of the substrate, characterized in that said at least one bump defines a curved surface transition zone having a fillet radius R in a range of 50 micron-500 micron.

2. The replication tool of claim 1, wherein said at least one bump defines a curved surface transition zone having a fillet radius R in a range of 100 micron to 120 micron.

3. The replication tool according to claim 1, wherein each cavity being limited by said curved surface transition zone serving as the bump portion, an inner edge between the cavity and the transition zone, an overflow volume and an outer edge between the transition zone and the overflow volume.

4. The replication tool according to claim 3, wherein said outer edge defines a peripheral resin run out zone with an inclination angle e in a range of 1-35 deg.

5. The replication tool according to claim 4, wherein the length of said peripheral resin run out zone is at least 20 micron, preferably at least 50 micron, preferably in a range of 60-80 micron.

6. The replication tool according to claim 2, wherein the distance between said curved surface transition zone and said substrate, when the tool is pressed against a substrate, is less than 60 micron, preferably in a range of 20-40 micron, said distance being measured at the highest point of said curved surface transition zone.

7. A method of manufacturing an element by means of a replication tool, comprising the steps of: providing a replication tool that defines the shape of the element; providing a substrate; pressing the replication tool against the substrate, with a replication material in a liquid or viscous or plastically deformable state located between the tool and the substrate; confining the replication material to a predetermined area of the substrate, which predetermined area exceeds the desired area of the element on the substrate, in at least one direction along the surface of the substrate by less than a predetermined distance; hardening the replication material to form the element, wherein said replication tool is a replication tool according to anyone or more of the preceding claims.

Description

[0023] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0024] FIG. 1 shows an embodiment of a replication tool according to the present invention.

[0025] FIG. 2 shows an embodiment of a replication tool according to the present invention.

[0026] FIG. 3 shows a replicated lens obtained by a replication tool according to the present invention.

[0027] FIG. 1 shows an embodiment of a replication tool according to the present invention. A replication tool 1 for replicating an element from a replication material 3, comprises a replication side, a cavity 5 on the replication side, defining the shape of one element, the replication tool 10 further comprises a bump portion 6, protruding, on the replication side, from the cavity 5, and further comprising means for confining the replication material to a predetermined area of the tool, when the tool is pressed towards a substrate 2, which predetermined area exceeds the desired volume of the element 3 in at least one direction along the surface of the substrate, i.e. an overflow volume 7. The bump portion 6 defines a curved surface transition zone having a fillet radius R in a range of 20 micron-300 micron. There is a distance between the tool 1 and the substrate 2, which distance is the smallest between the bump 6 and the substrate 2. The tool is hence nearly pressed towards the substrate but not completely in order to allow for a distance between the tool and the substrate. In other words the tool is pressed towards the substrate at a predetermined distance. This predetermined distance can be controlled by different methods, such as through positioning algorithms of the replication and/or a mechanical spacer. This spacer can be provided by the replication machine or can be integrated as an additional feature in the mold 1 as disclosed in the standoff 15 in WO 2015174929 and contact spacer 9 in EP 1 837 165. Construction 20 shows a replication 10 and a substrate provided with a polymer material 3.

[0028] FIG. 2 shows an embodiment of a replication tool according to the present invention. The main difference between replication tool 1 shown in FIG. 1 and replication tool 1 shown in FIG. 2 is the number of cavities 5. Construction 20 shows a replication 10 and a substrate provided with a polymer material 3. Peripheral zone comprises a buffer layer 7 with a thickness of <60 micron (preferred 20-40 micron) at the smallest distance of transition zone 6.

[0029] FIG. 3 shows a replicated lens obtained by a replication tool according to the present invention.

[0030] The minimum peripheral buffer thickness at transition zone, i.e. the shortest distance between substrate 2 and bump portion 6 is <60 micron, preferably 20-40 micron, since a value of >60 micron favors delamination. The minimum thickness is determined by capability replication process and by design.

[0031] The outer edge defines a peripheral resin run out zone with an inclination angle e in a range of 1-35 deg, wherein the slope may be linear or curved.

The present inventors found that such a minimum slope is needed for promoting centrifugal resin flow. Shape edge 4 (see FIG. 3) is determined by the meniscus of resin 3 or by other post processing processes thereby limiting the width (lithography, laser ablation). The preferred buffer width zone is in a range of 60-90 micron. Relevant application dimensions of lens 8 are: sag heights of optical elements: 5-2000, typically 60-350 microns; diameter clear apertures: between 50-4000 micron (typically 200-2000 micron). Typical material properties: cured polymer lens elements, wherein the related optical materials have CTE (>30 ppm/K) and E<4 GPA. Hard polymeric molding materials E>0.8 GPa (2-30 GPa), CTE 10<30 ppm/K. Stiff substrate (e.g. glass, quartz), (E>40 GPa and CTE<13 ppm/K) and optical coatings CTE: <10 ppm/K.

[0032] The present invention has been shown in the Table,

TABLE-US-00001 Embodiment Reference Embodiment Reference 1 1 2 2 Molding E = 4 GPa E = 4 GPa E = 6 GPa E = 6 GPa material CA 200 micron 200 micron 300 micron 300 micron Sag 100 micron 100 micron 200 micron 200 micron Fillet radius R 110 2 100 30 Buffer  30 micron  30 micron  25 micron 100 micron thickness @ edge 4 inclination 15 deg 25 deg 15 deg 0 deg angle θ run out zone 7 Length run  70 micron  70 micron  80 micron  80 micron out zone 7 Cracks in/at TiO2 SiO2 TiO2 SiO2 TiO2 SiO2 TiO2 SiO2 coat Dielectric Dielectric Dielectric Dielectric No cracks cracks No cracks cracks Failure in/at No Yes No Yes material

[0033] The Table shows the results of a design of experiment having different parameters. In “Embodiment 1” and the corresponding Reference the effect of the fillet radius has been shown. In “Embodiment 2” the corresponding Reference the effect of the application of a thinner buffer layer has been shown. The results have been provided in the bottom two rows.