Stock material or miscellaneous articles – Structurally defined web or sheet – Continuous and nonuniform or irregular surface on layer or...
Reexamination Certificate
1998-07-17
2001-11-27
Koehler, Robert R. (Department: 1775)
Stock material or miscellaneous articles
Structurally defined web or sheet
Continuous and nonuniform or irregular surface on layer or...
C428S142000, C428S469000, C428S472000, C428S472200, C428S696000, C428S698000, C428S600000, C428S687000
Reexamination Certificate
active
06322872
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a rolled product of metal having at least one surface with a light-spreading structure. Also within the scope of the invention is a process for manufacturing such a rolled product.
2. Discussion of the Prior Art
Present day lighting methods for high standard lighting in work-places make use of grooved mirror lights that have a reflector made of highly reflective aluminium based materials. Computer work-places in particular require special non-dazzling lamps with high lustre aluminium reflectors, so called BAP lamps that deflect the light correctly downwards and outside about 45% produce only little scattered light (<200 candela/m
2
, according to DIN 5035).
In many new developments such as e.g. secondary lighting, where the light source can no longer be seen directly, the high concentration of reflected light from the light source can be disturbing, if working with highly reflective surfaces. This effect is reinforced by use of the new T5 lamps that have significantly higher light densities. It is not possible to replace reflecting elements by diffuser surfaces, as scattered light is produced far from the reflecting angle, leading to a dazzling effect.
SUMMARY OF THE INVENTION
The object of the present invention is therefore to offer a structured surface with light spreading structure that reflects the light within a specific angle, but produces little scattered light beyond that angle. In addition, the surface should be simple, cost-favourable, recyclable and able to be manufactured in an industrial manner.
That objective is achieved by way of the invention in that the structured surface exhibits, in the rolling direction, a grooved structure that is wavy in cross-section in the form of a series of circular arcs or arc lengths having approximately the appearance of arcs, in which the maximum angle of inclination of a tangent to the arc lengths with respect to a plane defined by the surface is 1 to 15°, and the radius of the arc lengths lies between 0.1 and 20 mm.
In order to reduce the amount of scattered radiation, the roughness of the structured surface is preferably limited to a maximum value R
a
of 0.1 &mgr;m, preferably at most 0.05 &mgr;m, in particular at most 0.02 &mgr;m. The value R
a
is to be understood as the roughness after removal of the waviness due to the structure. The roughness value R
a
is defined in at least one of the standards DIN 4761 to 4768.
Preferred is an angle of inclination of 2 to 10°, preferably 3 to 8° and in particular 4 to 6°.
In a periodic structure the preferred values for the periodic distance lie between 0.01 and 10 mm, preferably between 0.05 and 0.5 mm and in particular between 0.1 and 0.4 mm. In a non-periodic structure the values for the periodic distance apply analogously to the width of the individual grooves.
The structure may exhibit a series of convex or concave shaped circular arc lengths. According to a further variant within the scope of the invention, both concave and convex circular arc lengths are present together in series, a preferred structure in particular being one in which the arc lengths are alternately convex and concave.
Although a periodic structure with a uniform arc radius is preferred, the radii on the same surface may be of different values and the grooved structure may also be in the form of a non-periodic structure.
For reasons of manufacture, or for storage purposes, instead of forming an edge, the transition between neighbouring lengths of arc or grooves may be be in the form of flat or rounded struts.
According to the invention the structured surface of the rolled product may be part of a sheet, strip or foil, said sheets, strips or foils preferably being of or containing aluminium or aluminium alloys, or the metals may be high lustre materials of aluminium or its alloys. In particular, aluminium or an aluminium alloy with aluminium of a purity in excess of 98.3 wt. % as its basis may be used.
Particularly favourable are rolled products according to the present invention the structured surface of which exhibits a structured surface layer that has been chemically, electrolytically or mechanically brightened, or anodised, or brightened and anodised.
Favourable is a structured surface that contains as superimposed layers, one or more layers of metals, semi-metals or their oxides, nitrides, sulphides or fluorides or mixtures thereof that have been deposited in vacuum.
Likewise favourable is a structured surface that features a brightened or anodised or brightened and anodised surface layer, and on this surface layer, as further superimposed layers, one or more layers of metals, semi-metals or their oxides, nitrides, sulphides or fluorides or mixtures thereof that have been deposited in vacuum.
At least one protective, transparent and corrosion resistant layer may be provided on the structured surface or surface layer.
On the structured surface there may also be at least one transparent layer that levels out the rilled pattern and has an optical refractive index that is sufficiently large to increase the refection of light.
Also, an underlayer and one or more layers of metals, semi-metals or their oxides, nitrides, sulphides or fluorides or mixtures thereof that have been deposited in vacuum as over-layers, may be provided on the structured surface.
An over-layer produced by a plasma-polymerisation process may also be provided on the structured layer.
An underlayer and one or more layers of metals, semi-metals or their oxides, nitrides, or fluorides or mixtures thereof, that have been deposited in vacuum may be provided as over-layers, and on top of that an overlayer that is deposited using the plasma-polymerisation process.
The under-layers on the structured surface may be deposited using the plasma-poly-merisation process.
The surfaces of sheets, strips or foils may be mechanically, electrolytically or chemically brightened. If the surface of the sheets, strips or foils has been anodised, then this anodising may be performed using various electrolytes such as acidic electrolytes of the following kind viz., sulphuric acid, phosphoric acid, tartaric acid, chromic acid and combinations thereof, using a direct or alternating current method. Batch or continuous strip anodising is possible.
Examples of a layer or layer systems comprising a plurality of layers deposited in vacuum onto the structured surface, or a surface layer already deposited (underlayer) may be for example:
As required, at least one bonding layer (layer A) such as e.g. a ceramic layer. Such layers may be or contain e.g. compounds of the formula SiOx, where x represents a number from 1 to 2, or Al
y
O
z
where y/z is a number from 0.2 to 1.5. Preferred is a bonding layer containing SiOx 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 above mentioned elements.
As required, a transparent protective layer (layer C) e.g. comprising or containing oxides, nitrides, sulphides, fluorides etc. of alkali, e.g. Li, Na, K, alkali-earth e.g. Mg, Ca, Sr, Ba, and/or transition metals such as 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 comprised of 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 to increase the degree of reflectivity as a result of parallel light reflection at the phase boundary of layer C and Layer D or further layers.
In the case of a plurality of dielectric and transparent layers, the layer thicknesses are to advantage selected such that the incident light undergoes constructive interference at the phase boundaries (&lgr;/4 layers).
Each of the above mentioned layers deposited in vacuum are e.g. 5 to 500 nm thick and the individual layers are preferably 5 to
Fuchs Roman
Hotz Walter
Alusuisse Technology & Management Ltd.
Cohen & Pontani, Lieberman & Pavane
Koehler Robert R.
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