WO2014044231A1

WO2014044231A1 - Lighting element

Info

Publication number: WO2014044231A1
Application number: PCT/CZ2013/000107
Authority: WO
Inventors: Tomas Tethal
Original assignee: IQ Structures sro
Current assignee: IQ Structures sro
Priority date: 2012-09-20
Filing date: 2013-09-17
Publication date: 2014-03-27
Anticipated expiration: 2015-03-20
Also published as: CZ306761B6; CZ2012649A3

Description

Lighting element Technical Field

The invention relates to a lightning element that comprises a body in which at least one light source with electric supply cables is arranged.

Prior Art

There exists a range of lighting elements having a ceramic body in which a light source with electric supply cables is arranged. Because the lifespan of conventional light sources (bulbs, fluorescent tubes, discharge lamps, etc.) is significantly shorter than lifespan of a ceramic body, the known lighting elements are construed so that the source of light can be removed from the lighting element and replaced.

With coming of modern light sources such as LED (Light-Emitting Diode) and later newly developed organic OLED (Organic Light-Emitting Diode) or electroluminescent foils, displays with active matrices (AMOLED), flexible displays, etc., the lifespan of these light sources has significantly extended.

In case that the body of the lighting element is made of fired ceramics, the light source, supply cables and other electronic components shall be installed in the ceramic body after firing of ceramics because firing of ceramics (even without any surface glaze) is carried out at high temperatures that could damage or destroy such components. These components therefore do not become any integral part of ceramics during production and are only connected with it (mechanically, by gluing, thread, etc.) after firing of the ceramic body.

In case of a so-called direct illumination, the light source is installed in the lighting element so that the illuminated area is lit either directly or in a combination with a front-embedded reflection or transmission optics. This arrangement is applied with overwhelming majority of lighting elements. Lighting through a waveguide is another option. In this case the light source is mostly out of the observer's eye axis. Light is transported from the source through a waveguide of which surface or interior is provided with a structure to enable output of light created usually by scattering centres that become multidirectional or oriented sources for the observer after passage or reflection of light. Then the observer can see light that scatters on scattering centres of the light output structure, not light coming directly from the light source.

Also in case of use of a waveguide the waveguide is not any integral part of the ceramic component and is installed later, after the ceramic component is fired, as a separate component that is fixed mechanically, using a glue, etc. Function of the waveguide is independent; the ceramic body surface is not any functional component of the light waveguide. For example, embedding of a LED lighting into a ceramic tile, more precisely, embedding of a LED light into a beforehand prepared hole in the tile. In some cases also some photo-luminescent pigments can be added to the ceramic product or onto its surface.

Scattering structures for output of light from the waveguide may comprise of non- homogenous particles distributed inside the light waveguide or a relief structure on its surface. The relief created usually by sanding, laser ablation, etching, mechanical scratching, etc. has a randomly created structure in these cases. Light scattered on such centre is usually distributed evenly in all directions. Therefore there is used an additional reflective (mostly white) layer from the side opposite to the direction of the required emission of light from the light waveguide, to increase intensity of scattered light into the observed direction.

Scattering centres of the structures for output of light from the waveguide (mostly on the waveguide surface) are often distributed non-homogeneously so that overall impression is homogenous when looking at the main area of the waveguide. In other words, uneven distribution of light scattering centres compensates gradual loss of light in the waveguide caused by scattering and emissions on these centres when passing through the waveguide. Density of scattering centres is usually lower close to the light source and increases with increasing distance from this source. Waveguides are often provided with a reflective (mostly white) layer (e.g. plastic foil, paper, paint) on sides from which light is not brought. The same can be made e.g. on the observer's opposite side, thus from the side of application of scattering centres. This increases intensity of light coming finally to the observer's eye. Another arrangement can be used in particular if scattering centres are in the waveguide volume.

The purpose of the invention is to create a lighting element that enables permanent embedding of a light source directly into the lighting element body.

Disclosure of the Invention

According to the invention, the mentioned goal can be achieved using a lighting element that comprises a body in which at least one light source with electric supply cables is arranged. The body is made of a geo-polymer composite and at least a part of the light source is embedded permanently in the geo-polymer composite body.

The main advantage can be found in compactness of the whole lighting element and in utilisation of good thermal conductivity of the geo-polymer composite for cooling of heated electric and electronic components.

In a useful embodiment a part of electric cables is embedded permanently in the geo-polymer body as well.

In other useful embodiment at the light source a waveguide with a structure for leading light out of the waveguide is arranged.

In another useful embodiment one end of the waveguide is oriented towards the geo- polymer composite body and at the opposite end the waveguide is provided with a structure for leading light out of the waveguide.

In the next useful embodiment the structure for leading light out of the waveguide is created directly in the geo-polymer composite body. For weakening or strengthening of reflection of the guided light it is useful when the structure for leading light out of the waveguide is provided with a levelling layer of a transparent plastic with refraction different from the refraction index of the plastic material used for the waveguide body.

In other useful embodiment the structure for leading light out of the waveguide is created in an additional layer of cast plastic and/or in an additional layer of cast plastic with a top layer, arranged on the bottom of the recess in the geo-polymer composite body.

In other useful embodiment the structure for leading light out of the waveguide is created by a beforehand made relief arranged on the bottom of the recess in the geo-polymer composite body.

In other useful embodiment the structure for leading light out of the waveguide is arranged for homogeneous or controlled distribution of light.

In other useful embodiment the structure for leading light out of the waveguide is created by a diffractive relief or a layer providing diffraction.

In another embodiment the light source includes LED and/or OLED and/or AMOLED. Brief Description of Drawings

The lighting element according to the invention will be described in details, with references to examples of different embodiments, shown schematically on drawings; Fig. 1 represents a lighting element for homogeneous distribution of light. Fig. 2 shows a section of the same element. Fig. 3 shows a lighting element, where a coat in form of a reflective layer is applied on the structure for leading light from the waveguide. Fig. 4 shows a lighting element, where a levelling layer of transparent plastic material is applied on the structure for leading light from the waveguide. Fig. 5 shows a lighting element with a layer of a transparent plastic between the top layer and waveguide body. Fig. 6 and 7 shows a lighting element without the waveguide, with light sources flushed with the body surface. Description of Preferred Embodiments

Fig 6 and 7 shows the simplest embodiments of the lighting element according to the invention, with the body 1 made of a geo-polymer composite. In all the below mentioned examples the light source 2 is represented by a set of known LED. However, specialists know that there can be also used another known light sources 2 such as OLED, AMOLED, electroluminescent foils, etc.

All LED incl. parts of electric supply cables 3 are embedded permanently in the body 1 made of a geo-polymer composite so that the upper LED surface is flushed with the surface of the body 1. Of course, according to a non-shown embodiment the LED may partly protrude from the surface of the body 1 or may be embedded under level of the surrounding surface. Electric supply cables 3 are terminated by non-shown electric contacts on the body 1.

The lighting element is made so that in the first stage all electric and electronic equipment (e.g. LED, cables 3 and non-shown remote control receiver, if any, electronic logics, control electronics, etc) is put into the mould that determines outer shapes and structure of its surface; these components shall be in the layout that corresponds to future functionality of these components in the lighting element. The components that may not be covered with the geo-polymer composite (e.g. output surfaces of LED, electroluminescent foils, OLED foils, fixed and flexible displays, AMOLED, optics, waveguides, etc.) are provided with a protective layer during production (e.g. by a plastic foil, paint, lacker layer etc.). The components that could be damaged by alkalic environment of non-hardened polymer are also provided with a protective layer (paint, grease, silicone, foil, etc.).

Then the mould is filled with the geo-polymer material in liquid state. Viscosity, colour and composition of the geo-polymer material are adjusted to fulfil the best mechanical, aesthetical and functional properties put on the lighting element.

This geo-polymer composite comprises of a mixture of a filler and binder, where the binder is a reactive substance, alkalic-activated aluminium-silicate with ability to polymerize. Because of mineral origin of this substance, it is called geo-polymer composite or geo-polymer. Its polymerization creates amorphous matrix by hardening of sol-gel dispersion of the initial raw materials in alkalic aqueous solution. The reaction is characterised by formation of siloxan bonds Si-O-T (where T= Si or Al in variable ratio Si:AI) arising from transition of bridge oxygen atoms of initial aluminiumsilicates and decomposition into non-bridge atoms and during polycondensation back to bridge atoms with formation of a solid substance. This conversion may run on air at normal temperatures and pressure as well as under other conditions (in frost or at higher temperatures up to 300°C and random pressure even without access of air). Metakaolinite, flue ash and slag are the initial raw materials.

The precursor of the geo-polymer composite in the described embodiment examples contains in average S1O2 within range from 20 to 95% by weight, AI2O3 from 5 to 89% by weight, and other substances converted to oxides, such as Fe2C>3 from 0 to 79% by weight, CaO from 0 to 79% by weight, Na₂0 from 0 to 35% by weight and K₂0 from 0 to 35% by weight, Li₂0 from 0 to 35% by weight, Ti0₂ from 0 to 79% by weight, where with specific surface of the filler and other additional substances more than 6^*10^"2 m²/g the minimum content of geo-polymer binder is 10% by weight without use of any other binders.

The geo-polymer composite is processed usually at working temperatures from 5 to 50°C, the best at ambient temperatures from 20 to 25°C. The upper limit is given by cryoscopic properties of the dispersion, i.e. by the temperature at which the dispersion freezes to a solid substance. The upper limit is given by technical parameters of the mould, i.e. by the temperature at which material of the mould, usually thermoplastic, already reacts sensitively by changes of properties (of course, also by the temperature when thermic decomposition of the precursor, whichever temperature is lower).

After the geo-polymer is hardened, the lighting element is taken out of the mould, the protective layer is removed (e.g. from the waveguide or LED surface) and all is left aged in damp environment at least for a few days. As needed, the geo-polymer surface can be provided with a functional or only aesthetical top layer, e.g. with a varnish (colour or transparent), laminated plastic foil, paint or electroplating. Colour layer can possibly be added into the mould as a thin layer before it is filled with liquid polymer.

As for the lighting element according to Fig. 1 and 2, light is emitted from light sources 2 not directly but through the waveguide 4.

The body 1 , made of a geo-polymer composite as described above and shaped as a wall tile, is provided a recess on its face, where light sources are embedded permanently. The waveguide 4 includes a structure 5 for leading light out of the waveguide 4; the structure comprises of scattering centres created so that first the designed structure 5 for leading light out of the waveguide 4 is made e.g. by a method of electron beam lithography or nanostereolithography as a master, then it is copied into a plastic of metal mould. Material of the mould shall show good copying properties for micro-relieves and low adhesion to the geo-polymer composite after its solidification. The mould surface comprises of smooth areas without any relief structure (future reflective interface of the light waveguide and areas with a relief in places of surface scattering centres).

The mould is filled with a liquid geo-polymer composite and after its solidification the geo-polymer composite is taken out of the mould. Geo-polymer composite shall be left aged in a damp environment at least for several days.

The geo-polymer surface is always nano-porous and therefore it is necessary to optimise sizes of these nano-pores by composition of geo-polymer so as to maximise reflection of light.

The waveguide 4 is then completed so that the recess in the body 1 is filled with a transparent or diffusional plastic. The plastic surface of the waveguide 4 can also be provided with a diffusional or transparent top layer 6 made of plastic, glass, etc. An air gap 7 can be left between the top layer 6 and waveguide 4.

According to a non-shown embodiment, naturally a commercially available set of a light source with a completed waveguide can also be embedded into the geo- polymer composite body 1 when casting it into the mould.

The embodiment according to Fig. 3 differs from the embodiment on Fig. 1 and 2 so that a coat 8 in form of a reflective layer, high- refraction index layer, etc. for modification of reflectivity is applied on all surfaces or only on certain places of the structure 5 for leading light out of the waveguide 4 on the bottom of the recess in the body 1.

The embodiment according to Fig. 4 differs from the embodiment on Fig. 3 so that a thin levelling layer of a transparent plastic 9 instead of the coat 8 on the structure 5 for leading light out on the bottom of the recess in the body 1 ; for weakening or strengthening of reflection, this transparent plastic layer has a different refraction index than the plastic used for the body of the waveguide 4.

The embodiment according to Fig. 5 differs from the embodiment on Fig. 4 so that the air gap 7 between the top layer 6 and body of the waveguide 4 is replaced by a layer of a transparent material 10, e.g. plastic.

According to a non-shown embodiment, the structure 5 for leading light out of the waveguide 4 can be created in a layer of plastic or in a layer of plastic with a surface treatment (e.g. plating), better on a geo-polymer composite layer, cast on the bottom of the recess in the body 1 made of geo-polymer composite. The structure 5 for leading light out of the waveguide 4, made in this way, can be significantly finer and its structure controlled so that it enables to achieve much better results in illumination as for homogeneity of light or just in formation of light into the desired images.

According to another non-shown embodiment, the structure 5 for leading light out of the waveguide 4 can be created as a beforehand made relief (a plastic foil with a relief, a plastic foil with a surface layer, a metal plate with a relief), inserted onto bottom of the recess in the geo-polymer composite body 1 and cast with a transparent and/or diffusional plastic.

Scattering centres of the structure 5 for leading light out can be arranged for homogeneous or controlled distribution of light. Density of scattering centres of the structure 5 for leading light out at the light source 2 is lower and increases with increasing distance from the light source 2 (see Fig. 1). Such uneven distribution of scattering centres compensates gradual loss of light in the waveguide 4, caused by scattering and emissions on these centres when passing through the waveguide 4. For distribution of light, this intentional uneven distribution of scattering centres of the structure 5 for leading light out achieves intentional non-homogeneity that can create a graphic pattern, alphanumerical symbol, bitmap, etc. This allows directing of light or a portion of light to one or more beforehand given directions or generation of two- dimensional pictorial perception or generation of spatial three-dimensional perception..

The waveguide 4 according to the shown embodiment examples is shaped as a flat plate, provided with a structure 5 for leading light out and on the other side it is either clear or its surface is diffusional. However, specialists know that the waveguide 4 can be shaped differently, e.g. as a cylindrical waveguide, a waveguide of a square, rectangular or half-round profile, linear waveguides, with different sections along the waveguide longitudinal axis, with a graphical motive, etc. The outer surface of the waveguide 4 does not have to be flushed with the surface of the body 1 and may protrude geometrically or graphically, create depressions, uneven surfaces, etc. In such case when casting a waveguide of a transparent plastic, it is necessary to use an additional mould copying the desired profile of the waveguide section, non- bordered by ceramic material.

The light waveguide 4 or waveguides may be designed so that they are terminated on the surface of the body 1 in the arrangement that corresponds to functional, graphical or aesthetical requirements for the lighting element.

Colour of the body 1 around the structure 5 for leading light out is chosen usefully so that it works as a good reflective layer, i.e. particularly white..

Light is transported from the light source 2 through the waveguide 4, whilst scattering centres of the structure 5 for leading light out become multidirectional or oriented sources for the observer after passage or reflection of light. The observer can therefore see light that is scattered on scattering centres of the structure 5 for leading light out, not light coming directly from the light source 2.

The waveguide points for extraction of light may also be provided with a controlled internal structure that allows more than diffusion of light only, e.g. also its diffraction, directing of light or a certain portion of light into one or more preset directions, generation of a three-dimensional perception, etc. The topology of scattering points themselves may create graphics and in case of use of diffraction even colour graphics.

Industrial applicability

The lighting element according to the invention can be used as a lighting element for household, industrial, interior, exterior purposes, as a structural component of constructions (e.g. public transport passenger shelters), lighting or information components in interior and exterior facing (wall tiles), as kitchen, bathroom, residential room, corridor, production hall, office accessories, etc.

The lighting element according to the invention can also be used as a component of sanitary facilities (washbasins, brackets, toilet bowls, bidets, bathroom tubs, shower enclosures, saunas, etc.), as a component of machines and equipment, transport means, information and warning systems, furniture, etc.

Claims

1. A lighting element comprising a body (1) in which at least one light source (2) with electric supply cables (3) is arranged, characterised in that the body (1) is made of geo-polymer composite and at least a part of the light source (2) is embedded permanently in the geo-polymer composite body (1).

2. The lighting element according to the claim 1 , characterised in that a part of electric supply cables (3) is embedded permanently in the geo-polymer composite body (1).

3. The lighting element according to the claim 1 or 2, characterised in that a waveguide (4) with a structure (5) for leading light out of the waveguide (4) is arranged at the light source (2).

4. The lighting element according to the claim 3, characterised in that one end of the waveguide (4) is oriented towards the outer surface of the geo-polymer composite body (1) and the other end of the waveguide (4) is provided with a structure (5) for leading light out of the waveguide (4).

5. The lighting element according to the claim 4, characterised in that the structure (5) for leading light out of the waveguide (4) is created directly in the geo-polymer composite body (1).

6. The lighting element according to the claim 5, characterised in that a levelling layer (9) of a transparent plastic is applied on the structure (5) for leading light out of the waveguide (4) while refraction index of this layer is different from the index of the plastic used for the body of the waveguide (4).

7. The lighting element according to any of the claims 1 to 4, characterised in that the structure (5) for leading light out of the waveguide (4) is created in an additional layer of cast plastic and/or additional layer of cast plastic with a top layer, arranged on the bottom of the recess in the geo-polymer composite body (D-

8. The lighting element according to any of the claims 1 to 4, characterised in that the structure (5) for leading light out of the waveguide (4) is created by a beforehand made relief, arranged on the bottom of the recess in the geo-polymer composite body (1).

9. The lighting element according to any of the claims above, characterised in that the structure (5) for leading light out of the waveguide (4) is adapted for homogeneous distribution of light.

10. The lighting element according to any of the claims 1-8 above, characterised in that the structure (5) for leading light out of the waveguide (4) is adapted for controlled distribution of light.

1 1. The lighting element according to any of the claims above, characterised in that the structure (5) for leading light out of the waveguide (4) is created by a diffractive relief or a layer providing diffraction.

12. The lighting element according to any of the claims above, characterised in that the light source (2) includes LED and/or OLED and/or AMOLED.