SUBSTRATE CERAMIC LAMINATE

Abstract

The invention relates to substrate ceramic laminates. In particular, the invention relates to substrate ceramic laminates in which the ceramic layer is a functional layer.

Claims

1. Component with functional surface.

2. Component according to claim 1, characterized in that the component comprises a substrate and a polycrystalline functional layer, the functional layer comprising the functional surface.

3. Component according to claim 2, characterized in that the polycrystalline functional layer comprises a ceramic.

4. Component according to one of claim 2, characterized in that the substrate comprises a plastic, a glass, a glass ceramic or a ceramic or a composite material or a flexible material.

5. Component according to claim 1, characterized in that the functional layer has a thickness of less than 2 mm, preferably less than 0.5 mm and especially preferably Jess than 100 m.

6. Component according to claim 1, characterized in that the substrate and/or the functional layer is transparent.

7. Component according to claim 1, characterized in that the functional layer is mechanically and/or chemically and/or thermally stable.

8. Component according to claim 1, characterized in that the functional layer has an optical function, particularly an antireflective effect and/or a filter effect.

9. Component according to claim 1 characterized in that the functional layer has a scratch-resistant and/or an anti-fog effect.

10. Component according to claim 1, characterized in that the substrate and the functional layer are connected to each other by means of an adhesion promoter.

11. Component according to claim 10, characterized in that the adhesion promoter is transparent and has a refractive index which lies between the refractive index of the substrate and of the functional layer, or a transparent adhesion promoter which has the same refractive index as the functional layer.

12. Component according to claim 1, characterized in that the functional layer is polished only on one side which is facing away from the substrate.

13. Component according claim 1, characterized in that the functional layer comprises a transparent ceramic, particularly an AlMg spinel, an Al.sub.2O.sub.3, an AlON, an SiAlON, ZrO.sub.2 or a mixed oxide ceramic from the system YAlMgO, wherein up to 5 wt. % doping elements can be contained.

14. Component according to claim 1, characterized in that the substrate and the functional layer are connected to each other by means of an adhesion promotor.

15. Component according to claim 1 characterized in that the adhesion promotor is an adhesive.

16. Component according to claim 1 characterized in that the adhesion promoter is a transparent adhesive.

17. Component according to claim 1, characterized in that the adhesion promoter is a transparent adhesive whose refractive index lies between the refractive index of the substrate and of the functional layer.

18. Component according to claim 1, characterized in that the adhesion promoter is a transparent adhesive whose refractive index is very similar to the refractive index of the functional layer, so that no perceivable phase transition or no perceivable boundary surface is produced for the intended use.

19. Use of a component according to claim 1 as a surface, particularly a transparent surface, which is subjected to wear, for example as a scanner surface of cash register systems, surfaces of blasting cabinets, floor coverings, watch glasses or stairs.

20. Use of a component according to claim 1 in optical components, particularly for displays of mobile phones, tablets or computers in general.

Description

[0013] An embodiment of the invention is preferred in which the functional layer comprises a ceramic, especially preferably a polycrystalline ceramic.

[0014] Depending on the intended use of the component according to the invention, a wide range of materials can be used for the substrate. For instance, plastics, glasses, glass ceramics or ceramics, but also composite materials and flexible materials can be used, this selection not being intended to constitute a limitation. For applications that require a transparent component, glasses, but also plastics are particularly suitable as substrate materials. For applications in which no transparency is desired or required, translucent or opaque materials can naturally also be used for the substrate.

[0015] In terms of the invention, a transparent ceramic is understood as being a ceramic having an RIT (real in-line transmission) of at least 40%, preferably of at least 60%, at 300 nm, 600 nm and/or 1500 nm light wavelength.

[0016] In order to eliminate scattered light from measurements, the transmission of the material is measured using a very narrow aperture angle of about 0.5 arid the measured value is then put in a ratio to the theoretically maximum transmission for this material. This then yields the determined RIT.

[0017] Theoretically speaking, transparency is thickness-independent when a perfect material is present and a perfect ceramic has been manufactured from it. However, as soon as the ceramic contains pores or the like, a scattering effect occurs at the phase boundaries of the pores, which increases as the thickness of the ceramic increases. This effect leads to decreasing transparency. In relation to this invention, the terms transparency and RIT refer to ceramics with thicknesses between 50 m and 100 mm.

[0018] Depending on the application, the functional layers can also comprise transparent, translucent or opaque ceramics. Transparent ceramics are especially preferred as functional layers, because they combine substantial advantages of glasses and ceramics with each other. In principle, all transparent ceramics can be used, b.sub.ut particularly spinets and preferably AlMg spinel, ZrO.sub.2, AlON, SiAlONAl.sub.2O.sub.3 or mixed oxide ceramics from the system YAlMgO. In conjunction with an also transparent substrate, these components can be used as alternatives to the very expensive sapphire monocrystal applications. In comparison to sapphire, functional layers made of ceramics offer various advantages:

[0019] Due to their monocrystalline structure, sapphire glasses are optically, mechanically and chemically anisotropic, i.e., they are optically birefringent and have preferred directions with respect to all other characteristics. As a result of their irregular structure, polycrystalline ceramics are substantially isotropic. In transparent ceramics whose minerals are cubic, this is also true with respect to optics; that is, there is no birefringence. Birefringence does exist in non-cubic, transparent ceramics, but because the grain size of the minerals must be less than 100 nm in order to produce transparency, the effect of birefringence is generally negligible in these polycrystalline materials.

[0020] Another advantage of ceramic, particularly of spinel ceramics, is the outstanding workability at a comparable hardness, compared to sapphire glasses. For example, if one uses a 0.5 to 2 mm-thick transparent ceramic (spinel) layer as a functional layer, a comparably scratch-resistant, chemically and thermally resistant layer, as in SOG composites, can be produced. Since the processing time (polishing to a predetermined surface quality) of a spinel ceramic only takes about 1/4 of the time required for the same processing of a sapphire glass, the processing time is shortened substantially, which leads to substantially lower costs.

[0021] The surprising finding that (spinel) ceramics have substantially better workability than sapphire glasses even though both have the same Mohs hardness can likely be attributed to the polycrystalline structure of the ceramic. It is assumed that individual crystals are broken out of the structure of the ceramic as a result of processing. The breaking-out of crystals appears to be more readily possible than the processing of the crystal structure as such.

[0022] Another advantage of ceramics, particularly of spinel ceramics, is a higher micro-scale damage tolerance compared to a sapphire glass of equal thickness; see FIG. 1. This figure shows a transparent spinel ceramic in the left image and a sapphire glass in the right image. Both materials underwent a Vickers hardness test which resulted in damage. The damage in the spinel ceramic corresponds substantially to the imprint of the Vickers indenter, whereas the damage in the sapphire glass has extended farther into the surroundings as a result of chipping.

[0023] Moreover, polycrystalline ceramics are more readily dopable than sapphire glasses. The doping can be performed to produce optical band filters and colorations, particularly in transparent functional layers. The doping can be up to 5 wt. % of the starting material. Doping elements worthy of consideration are elements from the series of the lanthanides, actinides, as well as Fe, Cr, Co, Cu and other known doping elements.

[0024] Other functions that can be produced with functional layers according to the invention are generally mechanical, chemical or thermal resistances or the optical functions already described above. In particular, an antireflective, scratch-resistant and/or anti-fog effect can be achieved, it also being possible, depending on the material, for several functions to be achieved with the same material.

[0025] According to an especially preferred embodiment of the invention, the substrate and the functional layer are joined together by means of an adhesion promoter, the adhesion promoter preferably being an adhesive.

[0026] If the component is to be transparent, a transparent adhesive can be used as an adhesion promotor, for example, whose refractive index lies between the refractive index of the substrate and of the functional layer.

[0027] Another advantage in using an adhesion promotor between substrate anti functional layer is that the functional layer need only be polished on its upper side, i.e., on the side of the functional layer which side faces away from the substrate, if an adhesion promotor with an appropriate refractive index was selected. The refractive index of the adhesion promotor should then be very similar to the refractive index of the functional layer, so that no perceivable phase transition or perceivable boundary surface is produced for the intended use.

[0028] In order to reduce costs and combine positive characteristics of different materials, very thin ceramic layers (<2 mm, better <0.5 mm, especially preferably 100 m) can be laminated with other transparent materials, particularly glass.

[0029] If the functional layer has a thickness of less than 100 m, it is flexible. This offers the advantage that bent substrates can be provided with such a layer without difficulty, since the functional layer can adapt to the bent shape of the substrate, That is advantageous, for example, in windshields or watch glasses and really in all non-planar substrates. Flexible materials such as plastics can of course also be provided with these functional layers.

[0030] What is more, if an adhesion promotor is used whose refractive index is adapted, then it is possible, for example, to apply an extremely thin (<500 m or even <100 m) thick transparent ceramic layer to a chemically hardened glass substrate without polishing the side of the ceramic layer that is in contact with the glass substrate or the adhesion promotor. The adhesion promotor, for example an adhesive, optically levels out the unevenness of the surface, since it has substantially the same refractive index as the ceramic. Then only the surface of the overall component needs to be polished. In this way, it is possible to polish very thin layers, e.g., layers less than 100 m thick.

[0031] It is therefore only necessary to polish the ceramic on the upper side of the component. That is more cost-effective, not least because two-sided polishing is rendered unnecessary. Compared to a sapphire glass, for example, a spinel ceramic can be polished in order to obtain the same surface quality in of the time. If polishing is additionally only required on one side of the functional layer instead of on both sides, of the time that would be required for obtaining the surface quantity of a comparable sapphire functional layer can be saved.

[0032] If the component does not need to be transparent, it is of course also possible to polish only one side of the functional layer or to leave the functional layer generally unpolished. The use of an adhesive with an adapted refractive index is then of course superfluous.

[0033] Specific applications for components according to the invention are scanner surfaces, for example of scanner cash registers, surfaces of blasting cabinets, as well as all transparent surfaces that are subject to wear, such as floor coverings, stairs or also watch glasses, for example.

[0034] Through a combination of very thin, chemically hardened glass, for example in a thickness from 0.3 to 5 mm, with an even thinner polycrystalline, transparent ceramic, for example with a thickness from 0.02 to 0.8 mm, extremely durable thin optical components can be produced which, for example, are outstandingly suitable for displays of mobile phones, tablets, computers in general, etc. By virtue of the substantially thinner ceramic layer, the scratch resistance of the ceramic as well as the other described characteristics can be exploited, and the greatest disadvantage of ceramicsthat of insufficient strengths in the case of small component thicknesses, such as 200 to 300 MPa, for examplecan be compensated by the chemically hardened glass. This system also offers the special advantage of being substantially cheaper than the SOG laminates.

[0035] Another aspect of the invention is the possibility of configuring larger, particularly transparent surfaces. Through the use of an adhesion promotor having an adapted refractive index, a large surface can be configured from many smaller tiles (multi-tile) that are embedded next to each other in the adhesion promotor, for example. In this way, flat displays can be created for large televisions, for example, that cannot be produced with sapphire glasses due to the monocrystal limitation.

[0036] The present invention therefore comprises particularly: [0037] Components with functional surface. [0038] Components, the component comprising a substrate and a polycrystalline functional layer, and the functional layer comprising the functional surface. [0039] Components according to one of the preceding points, the polycrystalline functional layer comprising a ceramic. [0040] Components according to one of the preceding points, the substrate comprising a plastic, a glass, a glass ceramic or a ceramic or a composite material or a flexible material. [0041] Components according to one of the preceding points, the functional layer having a thickness of less than 2 mm, preferably less than 0.5 mm and especially preferably less than 100 m. [0042] Components according to one of the preceding points, the substrate and/or the functional layer being transparent. [0043] Components according to one of the preceding points, the functional layer being mechanically and/or chemically and/or thermally stable. [0044] Components according to one of the preceding points, the functional layer having an optical function, particularly an antireflective effect and/or a filter effect. [0045] Components according to one of the preceding points, the functional layer having a scratch-resistant and/or an anti-fog effect. [0046] Components according to one of the preceding points, the substrate and the functional layer being connected to each other by means of an adhesion promotor. [0047] Components according to one of the preceding points, the adhesion promotor being transparent and having a refractive index which lies between the refractive index of the substrate and of the functional layer, or a transparent adhesion promotor which has the same refractive index as the functional layer. [0048] Components according to one of the preceding points, the functional layer being polished only on one side which is facing away from the substrate, [0049] Components according to one of the preceding points, the functional layer comprising a transparent ceramic, particularly an AlMg spinel, an Al.sub.2O.sub.3, an AlON, an SiAlON, ZrO.sub.2 or a mixed oxide ceramic from the system YAlMgO, wherein up to 5 wt. % doping elements can he contained. [0050] Components according to one of the preceding points, the substrate and die functional layer being connected to each other by means of an adhesion promotor. [0051] Components according to one o preceding points, the adhesion promotor being an adhesive. [0052] Components according to one of the preceding points, the adhesion promotor being a transparent adhesive. [0053] Components according to one of the preceding points, the adhesion promotor being a transparent adhesive whose refractive index lies between the refractive index of the substrate and of the functional layer. [0054] Components according to one of the preceding points, the adhesion promotor being a transparent adhesive whose refractive index is very similar to the refractive index of the functional layer, so that no perceivable phase transition or no perceivable boundary surface is produced for the intended use.

[0055] The present invention further comprises: [0056] The use of the components according to one of the preceding points as surface, particularly a transparent surface, subjected to wear, for example as a scanner surface of cash register systems, surfaces of blasting cabinets, floor coverings, watch glasses or stairs. [0057] The use of the components according to one of the preceding points in optical components, particularly for displays of mobile phones, tablets or computers in general.