LED Headliner
Encyclopedia
The Dictionary of Automotive Terms defines headliner
s "as fabric or vinyl upholstery on the interior of the roof of a vehicle". Wikipedia's definition is a bit more informative: "A headliner is a composite material that consists of a face fabric with nonwoven or foam backing that is adhered to the inside roof of automobiles or yachts". This definition reflects the fact that modern headliner consist of multilayer composite materials which bring together multiple functionalities, i.e. the requested look, haptik, stiffness and soundreduction needed in cars. Also for interior trim component, lighting is a functionality, which is getting more important today. A well known starlight Headliner was produced 2009 for the Rolls-Royce Phantom Sedan. Its starlight consisted of multiple illuminating glass fibers, all connected separately. In other words, the Lighting functionality was not part of the initial composite layers. Automotive companies, have realized the integration of electroluminescent light panels as dome light behind fabrics. Today, surface mount technology
(SMT/SMD) may use 0603 or 0402 SMD LEDs (< 0,3 mm thickness) enabling the production of flexible electronic circuits
below 1 mm thickness. As headliner interlayers, they are nealy as thin as electroluminescent panels mentioned above, but they may work with simple 12 VDC without need for electroluminescent inverters. The literature, describes precisely the hot vacuum-lamination of these thin LED Interlayers between glass and polymer composites. A LED Headliner describes a composite Headliner specification containing such an SMD LED Film for lighting purposes.
.
Since 2006, the Stella Consortium, a group of 12 companies and universities to develop stretchable electronics mounted on fabrics. This solution may open an option for electronics mounted in the last layer of headliners.
LED Headliner consist of multiple layer composite material
containing light emitting diode (LED) mounted on electro conductive Films. These films based on conductive printed or transparent conductive polymers or paper will substitute wires and transport electricity into the roof area of the vehicle, where other overhead systems may be powered. LEDs may be integrated in light guide plate, if their thickness and their weight will not affect the glueing and laminating process of the headliner. Thermoplastics like Polyester and Polypropylene are already in use in Headliner composites for optimised head impact countermeasure (HIC),. LEDFilm
embedded in LED Headliner may be perforated to enable a well define placement of these films on or to mounting elements within the composite. Perforation may contain Thermoplastic
or Adhesive
, in different shapes. Example of a shape would be the one of a connecting plug, which is present on both sides of the LED film. This type of connecting plug will reduce vibrations within the LED Film and the LED headliner, which is supposed to absorb noise within its composite.
Topview LED will produce small lighting area, starlike, in the Headliner fabric. Sideview LED, with a beam parallel to the substrate surface, will enable bigger area as well as pseudo-homogeneous lighting if used in bigger quantities. The best pseudo-homogeneous lighting is achieved by embedding side view LED films into transparent polymeric layers, which will act as lightguide materials.
Special interlayers of electroconductive LED Films based on flexible conductive polymer
s, on flexible printed circuit board
or on transparent conductive metals & oxides sputtered on polymer films which will be laminated between some layers of the composite Headliners.
New automotive composite Headliner base material are disclosed by many different companies, allows sound waves originating within a vehicle to penetrate deeply into the headliner where a significant portion of their energy is absorbed rather than reflected back into the vehicle. Consequently, modern headliner composites will often consist of following layers:
9. Release Sheet
8. Scrim Layer
7. Upper porous fibrous layer
6. Upper adhesive layer
5. Closed cell PU - foam
4. Lower porous fibrous layer
3. Lower (sound permeable) adhesive open cell PU barrier
2. Sound permeable cover stock foam layer
1. Coverstock material layer
Internal sound waves within the car will enter the coverstock material layer (1). Sound will diffuse to the upper adhesive layer and it will be reflected by the scrim layer(8). But it will be absorbed all the way through. In the case of LED Headliners one solution would be to laminate the polyester LED Film to the upper adhesive layer (7):
10. Release Sheet
9. Scrim Layer
8. Upper porous fibrous layer
7. Upper adhesive layer
6. Polyester LED Film (full area or perforated)
5. Closed cell PU - foam
4. Lower porous fibrous layer
3. Lower (sound permeable) adhesive open cell PU barrier
2. Sound permeable cover stock foam layer
1. Coverstock material layer
The Polyester LED Film (6) may also be perforated to allow the upper adhesive layer to connect to the closed cell PU foam (5). One possible production process for producing a composite headliner will comprise: Applying adhesive to the different surfaces of the foam cores; placing a fibrous layer to the adhesive coated surface of the foam cores; placing a scrim layer next to the lower porous fiber layers; preparing a coverstock sheet comprising a coverstock material layer and an adhesive barrier; and applying heat (100 - 160 °C) and pressure to the layered materials with a hot press. The pressures and temperatures of the lamination process mentioned above are quite similar to glass laminating temperatures. Consequently not only flexilble printed circuit board
s, but also LED embedded films, which are also laminated as inserts at 120 °C to produce transparent LED embedded glass
and dichroic LED Glass
are integrated in LED Headliner lamination process.
Headliner
A headliner is a composite material that is adhered to the inside roof of automobiles or yachts. It typically consists of a face fabric with nonwoven or foam backing. Headliners consist of multilayered composite materials that bring together multiple functionalities, including the requested look,...
s "as fabric or vinyl upholstery on the interior of the roof of a vehicle". Wikipedia's definition is a bit more informative: "A headliner is a composite material that consists of a face fabric with nonwoven or foam backing that is adhered to the inside roof of automobiles or yachts". This definition reflects the fact that modern headliner consist of multilayer composite materials which bring together multiple functionalities, i.e. the requested look, haptik, stiffness and soundreduction needed in cars. Also for interior trim component, lighting is a functionality, which is getting more important today. A well known starlight Headliner was produced 2009 for the Rolls-Royce Phantom Sedan. Its starlight consisted of multiple illuminating glass fibers, all connected separately. In other words, the Lighting functionality was not part of the initial composite layers. Automotive companies, have realized the integration of electroluminescent light panels as dome light behind fabrics. Today, surface mount technology
Surface-mount technology
Surface mount technology is a method for constructing electronic circuits in which the components are mounted directly onto the surface of printed circuit boards . An electronic device so made is called a surface mount device...
(SMT/SMD) may use 0603 or 0402 SMD LEDs (< 0,3 mm thickness) enabling the production of flexible electronic circuits
Flexible electronics
Flexible electronics, also known as flex circuits, is a technology for assembling electronic circuits by mounting electronic devices on flexible plastic substrates, such as polyimide, PEEK or transparent conductive polyester film. Additionally, flex circuits can be screen printed silver circuits on...
below 1 mm thickness. As headliner interlayers, they are nealy as thin as electroluminescent panels mentioned above, but they may work with simple 12 VDC without need for electroluminescent inverters. The literature, describes precisely the hot vacuum-lamination of these thin LED Interlayers between glass and polymer composites. A LED Headliner describes a composite Headliner specification containing such an SMD LED Film for lighting purposes.
Technology
Purchasers of middleclass automobiles also have preferences for vehicle exteriors with hidden or concealed light sources as a distinguishing decorative appearance for the vehicle. Big efforts are done to provide a lighting arrangement for the interior of an automotive vehicle in which the light source, such as LED, is recessed into the interior structure of the vehicle and covered with a layer of fabric. The light shall shine through the interior trim of the vehicle. Providing invisible light sources when not in use, but enough light through the fabric/foam layer when illuminated, is the main goal of any lighting HeadlinerHeadliner
A headliner is a composite material that is adhered to the inside roof of automobiles or yachts. It typically consists of a face fabric with nonwoven or foam backing. Headliners consist of multilayered composite materials that bring together multiple functionalities, including the requested look,...
.
Since 2006, the Stella Consortium, a group of 12 companies and universities to develop stretchable electronics mounted on fabrics. This solution may open an option for electronics mounted in the last layer of headliners.
LED Headliner consist of multiple layer composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
containing light emitting diode (LED) mounted on electro conductive Films. These films based on conductive printed or transparent conductive polymers or paper will substitute wires and transport electricity into the roof area of the vehicle, where other overhead systems may be powered. LEDs may be integrated in light guide plate, if their thickness and their weight will not affect the glueing and laminating process of the headliner. Thermoplastics like Polyester and Polypropylene are already in use in Headliner composites for optimised head impact countermeasure (HIC),. LEDFilm
LEDFilm
The LED Film, also called LED embedded film or LED lighting film is a thin and flexible electronic circuit with surface mounted light emitting diodes on the polymeric film...
embedded in LED Headliner may be perforated to enable a well define placement of these films on or to mounting elements within the composite. Perforation may contain Thermoplastic
Thermoplastic
Thermoplastic, also known as a thermosoftening plastic, is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently...
or Adhesive
Adhesive
An adhesive, or glue, is a mixture in a liquid or semi-liquid state that adheres or bonds items together. Adhesives may come from either natural or synthetic sources. The types of materials that can be bonded are vast but they are especially useful for bonding thin materials...
, in different shapes. Example of a shape would be the one of a connecting plug, which is present on both sides of the LED film. This type of connecting plug will reduce vibrations within the LED Film and the LED headliner, which is supposed to absorb noise within its composite.
Topview LED will produce small lighting area, starlike, in the Headliner fabric. Sideview LED, with a beam parallel to the substrate surface, will enable bigger area as well as pseudo-homogeneous lighting if used in bigger quantities. The best pseudo-homogeneous lighting is achieved by embedding side view LED films into transparent polymeric layers, which will act as lightguide materials.
Special interlayers of electroconductive LED Films based on flexible conductive polymer
Conductive polymer
Conductive polymers or, more precisely, intrinsically conducting polymers are organic polymers that conduct electricity. Such compounds may have metallic conductivity or can be semiconductors. The biggest advantage of conductive polymers is their processability, mainly by dispersion. Conductive...
s, on flexible printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
or on transparent conductive metals & oxides sputtered on polymer films which will be laminated between some layers of the composite Headliners.
New automotive composite Headliner base material are disclosed by many different companies, allows sound waves originating within a vehicle to penetrate deeply into the headliner where a significant portion of their energy is absorbed rather than reflected back into the vehicle. Consequently, modern headliner composites will often consist of following layers:
9. Release Sheet
8. Scrim Layer
7. Upper porous fibrous layer
6. Upper adhesive layer
5. Closed cell PU - foam
4. Lower porous fibrous layer
3. Lower (sound permeable) adhesive open cell PU barrier
2. Sound permeable cover stock foam layer
1. Coverstock material layer
Internal sound waves within the car will enter the coverstock material layer (1). Sound will diffuse to the upper adhesive layer and it will be reflected by the scrim layer(8). But it will be absorbed all the way through. In the case of LED Headliners one solution would be to laminate the polyester LED Film to the upper adhesive layer (7):
10. Release Sheet
9. Scrim Layer
8. Upper porous fibrous layer
7. Upper adhesive layer
6. Polyester LED Film (full area or perforated)
5. Closed cell PU - foam
4. Lower porous fibrous layer
3. Lower (sound permeable) adhesive open cell PU barrier
2. Sound permeable cover stock foam layer
1. Coverstock material layer
The Polyester LED Film (6) may also be perforated to allow the upper adhesive layer to connect to the closed cell PU foam (5). One possible production process for producing a composite headliner will comprise: Applying adhesive to the different surfaces of the foam cores; placing a fibrous layer to the adhesive coated surface of the foam cores; placing a scrim layer next to the lower porous fiber layers; preparing a coverstock sheet comprising a coverstock material layer and an adhesive barrier; and applying heat (100 - 160 °C) and pressure to the layered materials with a hot press. The pressures and temperatures of the lamination process mentioned above are quite similar to glass laminating temperatures. Consequently not only flexilble printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
s, but also LED embedded films, which are also laminated as inserts at 120 °C to produce transparent LED embedded glass
Transparent LED embedded Glass
Transparent LED-embedded glass is a new composite material containing light-emitting diodes . It is used as building material and as glass type for many different products. This new technology enables materials, new applications in electronics and architecture...
and dichroic LED Glass
Dichroic LEDGlass
(Dichroic LED Glasses laminated by RighettiDichroic LEDGlass is a new composite material which is based on the technology of transparent LED embedded glass. Dichroic LED glasses differ from transparent Ledglass: The reflected colour of the LED Glass is a function of the angle of light reflection...
are integrated in LED Headliner lamination process.