Method for producing substrate stacks for further processing into composite sheets for optical light guide elements
AssigneeSchott AG
InventorsStefan WEIDLICH, Yakup GÖNÜLLÜ, Hauke ESEMANN, Fangtong XIE, Frederik BACHHUBER
Life of this patent
Estimating the term…
Abstract
A method for producing a stack for further processing into composite sheets, the method comprising bonding two or more sheet-like substrates with an adhesive layer; also to a method for producing a composite sheet and to a composite sheet, preferably for use as an optical light guide element or in an optical light guide element, in particular for use in the field of augmented reality are disclosed.
Claims18
A method for producing a stack for further processing into composite sheets, comprising bonding two or more planar substrates with a layer of adhesive, the planar substrates each having a first and a second surface that are parallel to each other, comprising the steps of:
- a) providing a first planar substrate, at least the first surface of the first planar substrate being optionally pretreated by cleaning, plasma treatment and/or applying an adhesion promoter,
- b) applying an adhesive having a first viscosity to the first surface of the first substrate and rotating the first substrate, the adhesive being distributed on the first surface of the first substrate, and the resultant layer of adhesive having a layer thickness of from 0.2 μm to 5.0 μm,
- c) optionally varying the viscosity of the adhesive by heating or cooling, and
- d) bonding the first planar substrate to a second planar substrate to form a first stack (1, 11), comprising contacting the first surface of the first substrate with the second surface of the second substrate and curing the layer of adhesive.
A composite sheet, comprising a first surface and a second surface that are parallel to each other, and a lateral face, and two or more planar substrates that each have a first and a second surface that are parallel to each other, the planar substrates being bonded by at least one layer of adhesive, the composite sheet preferably meeting at least one of the following conditions:
- i) the first and/or the second surface of the composite sheet have a roughness Rq of <5 nm;
- ii) the composite sheet has a TTV of less than 10 μm, based on the first and the second surface of the composite sheet;
- iii) the composite has a warp of <100 μm, based on the first and the second surface of the composite sheet;
- or
- iv) the composite has a bow of <100 μm, based on the first and the second surface of the composite sheet.
Dependencies are inferred from the claim text.