Transparent LED-embedded glass

Introduction
Transparent LED-embedded glass is a new composite material containing light-emitting diodes (LEDs). 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. Due to the use of a cold curing pick and place process, this technology is also related to electronics manufacturing and electronics engineering. This article is focusing on published specifications enabling building materials which will meet security and legislation aspects of laminated glass.
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Composite specification
The LED-glass composite material may consist of using transparent metallized glass as electricity conductor. In this case the final composite specification will be:
* Top Layer:...Standard glass
* Interlayer:...Transparent thermoplastic material like TPU, PVB or EVA
* Interlayer:..LEDs (light-emitting diodes)
* Bottom layer:...Metallised bottom glass
Thermoplastics
The transparent thermoplastic material will usually show a quite similar light refractive index compared to glass. Typical thermoplastics used in the glass industry to produce these type of security glazings will consist of Thermoplastic Polyurethane (TPU), Ethyl-Vinyl-Acetate (EVA) or Poly-Vinyl-Butyral (PVB).
Production
The specification mentioned above will typically be produced in following steps:
# Vacuum sputtering of transparent conductive material on glass
# Cutting the glass to the final size
# Laser ablation of parts of the conductive material
# Mounting SMD LEDs on the glass by means of a pick-and-place process
# Lamination of the glasses according the specification mentioned above
Because most of the glass companies are not skilled to mount LEDs (light emitting diodes) onto metallized glass, it makes sense to locate the LEDs on a separate transparent conductive polymeric interlayer,, which may be laminated by any glass lamination unit. In other words, the remaining process for glass lamination units will consist of laminating together standard glass using 2 layers of thermoplastic interlayers to sandwich ready to use LED-embedded films. This process will be quite similar for 3D curved LED-glass. The final specification will be:
* Top layer:.. Glass
* Interlayer:..Transparent thermoplastic material like TPU, PVB or EVA
* Interlayer:..LED (light emitting diodes)on transparent conductive Polymer
* Interlayer:..Transparent thermoplastic material like TPU, PVB or EVA
* Bottom layer:..Glass
Within this last specification mentioned above, the 2 thermoplastic layers together with the LED interlayer will reach a total thickness of about 2 mm. The usually very economical PVB is the most used lamination interlayer. Its lamination is based on a nip roller pre-heating step followed by an autoclaving process with a final stage ideally below 125 °C and 14 athmospheres. However, polyester has a better adhesion to TPU, to EVA or to EVASafeEVASAfe, which are often laminated using simple vacuum tables. EVASafe contain some hygroscopic crosslinking agent, which will allow its partial crosslinking to active sites of the substrates. TPU may be used up to 125 °C. EVASafe should be used below 110 °C. These transparent conductive thermoplastics may also be used for transparent heating of glass laminates.

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