Patent Application
20060260547
1. Field of the Invention
The invention relates to an apparatus for the vapor deposition of a layer, in particular of a hydrophobic and/or oleophobic top coat layer, onto a front and a rear side of planar substrates.
Antisoiling, in particular hydrophobic and/or oleophobic, top coat layers for reducing water stains and soil adhesion on optical substrates, such as eyeglass lenses, for example, are known. Thus, German Published, Non-Prosecuted Patent Application DE 37 01 654 A1, corresponding to Japanese Patents JP62178902, JP62178903, JP62247302, JP62169102, JP5341107 and JP7098414, describes treating articles coated with silicon oxide, such as lenses, display panels and the like, with a material which produces a water-repellent effect after reaction or absorption at the surface to be treated. In the case of eyeglass lenses, the top coat layer is usually applied on antireflection layers, but top coat layers on plastic lenses provided only with a hard coating or uncoated mineral glasses are also known.
Optical lenses provided with a top coat layer, as are used in eyeglasses, for example, are nowadays produced in industrial process installations in which, before the top coat layer is produced, usually the lens is shaped and cleaned, a hard coat is applied by dip-coating or spin-coating, drying and heat treatment are effected before application of an antireflection layer and, as a final step, the coating with the hydrophobic and olephobic top coat layer is effected. As an alternative, it is customary to also produce the hard coat through the use of a PECVD process and the antireflection layer through the use of sputtering.
A method of applying a thin water-repellent and oil-repellent layer on a silicon oxide coating with antireflective properties can be gathered from U.S. Patent Application Publication No. US 2004/0142185 A1. That publication proposes using, as the evaporation source for a hydrophobic reactive organic component, a porous ceramic matrix impregnated with the hydrophobic reactive component or a block of metal fibers.
German Published, Non-Prosecuted Patent Application DE 44 30 363 A1, corresponding to Canadian Patent No. 2,157,070, discloses a vacuum coating installation in which an antiscratch layer and optical layers are vapor-deposited onto optical substrates through the use of an electron beam evaporator with simultaneous action of a plasma or ion beam.
In that case, the material for the coating is evaporated by the electron beam evaporator and passes through the plasma or ion beam directed onto the substrate, with the material being activated. A hydrophobic layer made of TMDS is vapor-deposited as a covering layer. In that case, the substrates are disposed on a spherical cap and mounted in spring rings, for example. If the front and rear sides of the substrate are intended to be coated, the substrate has to be turned. For that purpose, the spherical cap may be embodied, for example, in such a way that individual segments of the spherical cap can be rotated about their axis and the rear side of the substrate can be coated after turning.
The disadvantage of that installation is that the hydrophobic effect of the top coat layer applied last to the front side is partly eliminated again by the coating of the rear side, in particular by the action of ions.
It is accordingly an object of the invention to provide an apparatus for coating substrates on both sides, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known apparatuses of this general type and which can be used to produce a top coat layer on both sides of a substrate in a simple, reliable and cost-effective manner.
With the foregoing and other objects in view there is provided, in accordance with the invention, an apparatus for the vapor deposition of a layer, in particular of a hydrophobic and/or oloephobic top coat layer, onto a front and a rear side of planar substrates, comprising at least one vacuum chamber with a substrate holder for receiving at least one substrate, a first evaporator disposed opposite the front side of the substrate, and a second evaporator disposed opposite the rear side of the substrate. In this case, at least the second evaporator is formed as a basket-type wire container and the wire container is disposed between the substrate holder and a radiation plate. Evaporated material which can emerge from the wire container in all directions is directed or can be directed in the direction of the substrate through the use of the radiation plate. At least one pellet with the material to be evaporated is disposed or can be disposed in the wire container. The wire container is formed, in particular, of metal wire having a high melting point, for example tungsten, and the wire container is formed in such a way that the pellet cannot fall out.
In accordance with another feature of the invention, the wire container is heated and preferably concomitantly heats the radiation plate through the use of radiant heat and/or the radiation plate can be heated separately, thereby preventing condensation of the coating material on the radiation plate.
Metal plates of molybdenum, tantalum, tungsten, copper and/or high-grade steel may preferably be used as the radiation plate. However, it is also possible to use materials such as ceramic or graphite.
In accordance with a further feature of the invention, the coating material to be evaporated is incorporated in the cavities of the pellet formed of a porous material. The porous material is preferably inert, that is to say no reaction takes place between the porous material of the pellet and the coating material. The porous material has its melting and boiling point significantly above the evaporation temperature of the coating material and preferably is formed of pressed aluminum oxide (Al2O3), a sintering metal and/or metal chips.
In accordance with still a further feature of the invention, the second evaporator is disposed above the substrate holder, so that substrates disposed in the substrate holder can be coated on both sides without having to be turned, preferably also simultaneously from both sides, with a top coat layer.
In accordance with an additional feature of the invention, the first evaporator is likewise formed as a wire container with a radiation plate. The radiation plate is preferably disposed in the wire container and the pellet is disposed or can be disposed on the radiation plate.
In accordance with yet another feature of the invention, disposed alongside the first evaporator for evaporating the top coat layer that is to be applied as the last layer to the substrate on both sides, may be a further evaporator, for example an electron beam evaporator, and, if appropriate, a plasma or ion beam source below the substrate holder. As a result, functional layers, for example antireflection layers, can be vapor-deposited onto the substrate on one side, if appropriate with the action of a plasma or ion beam, before the top coat layer is applied on both sides.
In accordance with yet a further feature of the invention, if the functional layers are intended to be applied to the substrate on both sides, the substrate holder may preferably be trapezoidal segments of a spherical cap which can be rotated about their longitudinal axis and through the use of which the substrates can be turned within the vacuum chamber. Alternatively, the substrate holder may be embodied as a turnable paddle.
In accordance with a concomitant feature of the invention, the wire container is formed as a helix, in particular as a conical helix. This embodiment permits a simple fixed mount and a simple exchange of the pellet with the material to be evaporated and enables the evaporated material to emerge unimpeded.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an apparatus for coating substrates on both sides, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawings in detail and first, particularly, to
The apparatus illustrated in
The substrate holder 6, which is in the form of a spherical cap, includes individual trapezoidal segments 10 on which the substrates 7 are disposed. The segments 10 can be rotated about their longitudinal axis for the purpose of turning the substrates 7. The substrates 7 are mounted in the segments through the use of spring rings, for example.
In order to apply a functional layer to one side of the substrates 7, a plasma beam is generated through the use of the plasma source 9 and a monomer with layer-forming substances is introduced into the plasma beam through a gas inlet 11. In addition or as an alternative, it is also possible for functional layers to be vapor-deposited through the use of the first evaporator 4 or through the use of a non-illustrated electron beam evaporator.
In order to coat the other side of the substrates 7 with one or more functional layers, they are turned by rotation of the segments 10 and coated in the manner described above.
The concluding coating of the substrates 7 with a hydrophobic top coat layer on both sides is effected through the use of the first evaporator 4, which is illustrated in detail in
The second evaporator 5 illustrated in
The first evaporator 4 illustrated in
This application claims the priority under 35 U.S.C. ยง119, of German utility model No. 20 2005 008 165, filed May 20, 2005; the entire disclosure of the prior application is herewith incorporated by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2005 008 165.5 | May 2005 | DE | national |
