Rolled metal product used as a light-guiding structure

Details Rolled metal product used as a light-guiding structure Rolled metal product used as a light-guiding structure

2002-04-12

2002-12-03

Font, Frank G. (Department: 2877)

Optical waveguides

Miscellaneous

C385S136000, C385S900000, C359S591000, C359S596000

Reexamination Certificate

active

06490403

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a rolled metal product having at least one structured surface as a light-guiding structure, as well as to a process for its manufacture and its use.
It is known from DE-OS 42 15 968 to employ light-deflecting ceilings, e.g. metal elements with a structure, for a specific light-guiding effect. The structure of the light-defecting ceiling may e.g. be in the form of rills and the structural magnitude should preferably be 1 to 50 m. Producing such structures is expensive, especially as the effective, light-guiding faces of the structure should be as large a fraction of the whole as possible, and the edges between the faces should constitute as small a fraction of the whole as possible. Up to now it has not been possible to produce such structures by industrial methods, especially by efficient manufacturing processes.
DE 42 15 968 describes daylight guiding structures for the wall and ceiling region of a room which feature grooves or points.
SUMMARY OF THE INVENTION
The object of the present invention is therefore to provide light-guiding structures which are light, cost favourable and can be manufactured in an industrial manner i.e. in large series production. Thereby, to produce the structured surface as a light-guiding structure, manufacturing methods are to be avoided which cause large material loss and tool wear by chip-forming methods.
This objective is achieved by way of the invention by means of rolled products of metal having at least one structured surface, which exhibits a ribbed pattern running in the rolling direction and is tooth-like in cross-section. The tooth-like cross-section represents a periodic structure in the form of rows of triangles, the bases of which follow each other. One side of the triangle runs at an angle &agr;, and the other side at an angle &bgr; from the base which is of length l, &agr; being an angle of 5 to 60°, &bgr; being an angle of 10 to 90° and length l is 0.01 to 10 mm.
The base of the triangles, which are in line, preferably form a straight line, but may however lie along a curved line.
Preferred are rolled products of the kind mentioned above, and such that at the line of contact of both sides of a triangle an edge of radius r
1
is formed, where r
1
is e.g. smaller than l/2, usefully less than l/4, preferably less than l/6, in particular preferably l/10, and in particular is 0 or at least tends towards 0 mm.
Likewise preferred are rolled products of the above mentioned kind where at the line of contact of two adjacent triangles an edge with a radius r
2
of 0 mm or a concave rounded line of contact with a radius r
2
is formed, r
2
being smaller than l/2, usefully less than l/3, preferably less than l/4, in particular preferably less than l/6.
Significant for the present invention is the roughness R
a
of the sides of the structured surface, the ribbed pattern—or at least the part of the ribbed structure which deflects the light—advantageously exhibiting a roughness R
a
of 0 to 1 &mgr;m, usefully less than 0.1 &mgr;m, preferably less than 0.05 &mgr;m and in particular less than 0.02 &mgr;m.
Especially preferred is a structured surface in which the angle &agr; is an angle of 5 to 60° and usefully from 10 to 50°.
Especially preferred is a structured surface in which the angle &bgr; is an angle of 10 to 90°, usefully from 15 to 90° and advantageously from 30 to 90°.
Useful is a structured surface in which the height h of the ribbed pattern is 5 mm or less, preferred is a height h of 0.1 to 2 mm.
According to the invention the structured surface of the rolled product may be part of a beam, sheet, strip or a panel or foil, whereby the beams, sheets, strips, panels or foils may be of metal, preferably aluminium or aluminium alloys, or the metals may be bright finish materials of aluminium or its alloys. In particular, aluminium or aluminium alloys having as their basis aluminium of a purity greater than 98.3 wt. % may be used.
Particularly favourable are rolled products according to the present invention the structures of which exhibit a brightened or anodised or brightened and anodised structured surface layer.
Favourable is a structured surface which exhibits as overlying layers one or more vacuum deposited layers of metals, semi-conductors (also called semi-metals), or their oxides, nitrides or fluorides or mixtures thereof.
Also favourable is a structured surface which exhibits a brightened or anodised or brightened and anodised structured surface layer and on this surface layer, as overlying layers, one or more vacuum deposited layers of metals, semi-conductors or their oxides, nitrides or fluorides or mixtures thereof.
At least one transparent scratch resistant and corrosion resistant layer may also be provided on the structured surface or on a surface layer.
Also, the structured surface may feature an under layer and one or more vacuum deposited layers of metals, semi-conductors, or their oxides, nitrides or fluorides or mixtures thereof as overlying layers.
The structured surface may also be provided with an outer layer deposited by the plasma polymerisation process.
Also, on the structured surface there may be an under layer and one or more vacuum deposited layers of metals, semi-conductors, or their oxides, nitrides or fluorides or mixtures thereof as an overlying layer and, on top of this an outer layer deposited by the plasma polymerisation process.
The under layers on the structured surface may be deposited by the plasma polymerisation process.
The surface of the sheets, strips or foil may be brightened electrolytically or chemically. If the surface of the sheets, strips or foils are anodised, then this may be performed using various electrolytes such as the following; acidic electrolytes viz., sulphuric acid, phosphoric acid, citric acid, tartaric acid; chromic acid electrolytes; and combinations thereof, in a direct current or alternating current process etc. Both batch anodising and continuous strip anodising are possible.
Examples of a layer or a layer system involving a plurality of layers which may be deposited in vacuum onto the structured surface or onto an already deposited surface layer (under layer) may be e.g.:
As required, at least one adhesive layer (layer A) and e.g. a ceramic layer. Such layers may e.g. contain or comprise compounds having the formula SiO
x
, where x is a number 1 to 2, AlyO
z
, where y/z is a number from 0.2 to 1.5. Preferred is an adhesive layer containing SiO
x
where x has the meaning described above.
A light-reflecting layer (layer B), e.g. a metallic layer containing or comprising e.g. Al, Ag, Au, Cu, Cr or alloys e.g. containing at least one of the mentioned elements.
As required, a transparent protective layer (layer C) comprising or containing oxides, nitrides, fluorides, etc., of alkali metals e.g., Li, Na, K, alkali-earth metals e.g. Mg, Ca, Sr, Ba and/or transition metals such as e.g. Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Y, Zr, Nb, Mo, Te, Ru, Rh, Pd, Hf, Ta, W, Re, Os, Ir, Pt and/or Lanthanides such as e.g. La, Ce, Pr, Nd, Pm, Dy, Yb or Lu etc. Examples are layers containing or comprising PrTi-oxide and MgF
2
etc. Further, instead of only layer C, two or more transparent layers (layers C, D, . . . ) with different refractive indices may be provided in order to improve the degree of reflectivity due to partial light reflection at the phase boundaries of the layer C and layer D or further layers.
In the case of a plurality of dielectric and transparent layers the layer thicknesses are advantageously chosen such that the incident light experiences constructive interference at the phase boundary (&lgr;/4 layers).
Each of the above mentioned layers deposited in vacuum is e.g. 5 to 500 nm (nanometer) thick, preferably 5 to 100 nm thick.
Useful is a layer B. Preferred is a layer system containing a layer B and a layer C or a layer system containing a layer B, a layer C and a layer D.
The layers may be deposited on the surface according to the invention or on an already deposited layer e.g. by gas or vapour phase deposition in vacuu

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