Manufacturing optical elements

Abstract

A method of manufacturing an element using a replication tool, including the steps of providing a replication tool that defines the shape of the element; providing a substrate; pressing the tool against the substrate, with a replication material 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 covering the substrate, in at least one direction along the surface of the substrate by less than a predetermined distance.; hardening (e.g. curing) the replication material to form the element.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention is in the field of manufacturing miniature optical or mechanical elements, in particular refractive optical elements or diffractive micro-optical elements, by means of a replication process that includes embossing or molding steps. More concretely, it deals with a method of replicating an optical element and a replication tool therefore. [0003] 2. Description of the Related Art [0004] Replicated optical elements include diffractive and / or refractive micro-optical elements for influencing an optical beam in any pre-defined manner, refractive elements such as lenses, potentially at least partially reflecting elements etc. [0005] When optical elements are produced by replication, there is often a basic configuration involving a substrate and replication material on a surface thereof, which replication material is shaped and hardened in the course of a replication process. Often, the dimension perpendicula...

AI Technical Summary

Benefits of technology

[0024] Before the replication tool and the substrate are brought together for the embossing process, replication material in a liquid or viscous or plastically deformable state is placed on the replication tool and / or the substrate. The replication tool may comprise a plurality of sections each defining an element to be replicated. Then, preferably the method comprises applying a (possibly pre-defined) volume of replication material locally and individually, at laterally displaced positions, each position corresponding to one section, to at least one of the tool and the substrate prior to pressing the tool against the substrate. This allows providing a plurality of cavities, each corresponding to an optical element, with an optimal amount of replication material. By this, the volume of surplus replication material that must be removed or diverted from the critical areas is reduced or eliminated, as compared to the case where a plurality of elements would be formed from a single blob of replication material.

[0026] The element volume covers a part of the substrate and constitutes the functional part of the element. The remainder of the cured replication material may fill a volume at the sides of the element, i.e. the region of space adjacent to both the substrate and the functional part of the element, and does not interfere with the function of the element. The invention allows for controlling how far the replication material may move along the substrate at each side of the element volume.

[0038] This allows for the diverting of the replication material away from the critical areas and guiding it to an overflow volume located in a noncritical area.

[0047] The replica (for example a micro-optical element or micro-optical element component or an optical micro-system) may be made of epoxy. The hardening step, which is done while the replication tool is still in place may then be an UV curing step. UV light curing is a fast process that allows for good control of the hardening process. The skilled person will know other materials and other hardening processes.

Problems solved by technology

However, small volumes of dispensed liquid or viscous material are generally difficult and costly to control.

However, there might be areas sideward of the element where replication material is not wanted in later replication steps.

In certain applications, the fabricated elements must, for example, be used in combination with other elements, and the residual material will impair the function of the combined structure.

The residual material, if it covers critical areas, may interfere with further processing steps of the stack comprising the semiconductor wafer and the lenses, e.g. bonding.

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