Autotex hardcoated polyester films are playing a crucial role in a range of advanced electroluminescent (EL) lamps being used for dashboard displays and instrumentation.

Autotex hardcoated polyester films are playing a crucial role in a range of advanced electroluminescent (EL) lamps being used for dashboard displays and instrumentation in the 200mph Ascari KZ1 supercar. Manufactured by Pacel Electronics, the EL lamps have been designed and developed to offer exceptionally high levels of performance, combining excellent levels of light transmission and stability under a wide range of operating temperatures with an extended operating life. Based in Poole, Dorset, Pacel Electronics has been producing EL lamps and associated systems for over 20 years, for use in military, aerospace, marine and, increasingly, automotive applications.

In each case, the company's products are designed to match the specific needs of each customer, with lamps often being used in systems that are exposed to extremes of temperature, shock, vibration and humidity, providing a thin, flexible method of illumination that is easy to integrate into instrument and front panel displays.

EL lamps are constructed from a three-layer sandwich of materials, typically measuring around 0.3mm in thickness and resembling a conventional capacitor in design.

The individual layers that make up the composition of the lamp between the two conductors of the capacitor, are produced by screen printing film substrates with conductive inks.

The front conductor is usually a clear film sputtered with a conductive Indium Tin coating: the rear conductor is usually a screen-printed silver ink.

Connecting an AC voltage, (typically 115Vrms, 400Hz), across the electrodes energises the phosphor particles, causing them to emit energy in the form of light.

Although early EL lamps were susceptible to failure and had a relatively short operating life, often due to the ingress of moisture, the latest versions manufactured by Pacel Electronics utilise special micro-encapsulated phosphors, which are virtually unaffected by moisture, humidity and changes in temperature.

As a result, operating life has been significantly extended, creating the potential for far wider application, with the automotive sector in particular now building EL lamps into both mass market and specialist high performance, low volume vehicles.

For Ascari, the use of EL lamps to backlight instrument displays, including speedometers, tachometers and heating and lighting controls provides an efficient, reliable and aesthetically pleasing method of backlighting.

As Nick Bainton, of Pacel Electronics, explains, 'One of the key criteria for the Ascari engineers was to find a method of illumination that reflected the quality and style of the KZ1 and, in particular, ensured a consistent, easily controllable and low power solution that could be incorporated into highly complex instrument displays simply and at a competitive price'.

The solution developed by Pacel Electronics incorporates the latest micro-encapsulation technology, with the two outer protective layers being manufactured using MacDermid Autotype's Autotex hardcoated polyester film.

This has been developed specifically for use both with high performance screen inks and sputter deposition processes to provide an extremely hard wearing material that is resistant to surface abrasion, solvents and chemicals.

Nick Bainton adds that, 'Autotex is exceptionally stable, both during processing and in subsequent use, so is ideal for applications such as automotive interiors where temperatures and humidity can fluctuate widely'.

'Most crucially, the performance of each EL lamp, in terms of evenness of illumination, depends on achieving a precise thickness for each individually printed layer'.

'With Autotex, we have found that material variations are almost non-existent and are always below two microns, which is well within the tolerances to which we work' Nick Bainton concludes, 'The overall performance of Autotex means that we have standardised on this material for all our commercial EL applications and have built up an excellent relationship with MacDermid Autotype, with their product specialists providing us with both technical and applications support, especially for new projects'.

'Indeed, we are currently working on a number of exciting new developments for a new generation of moulded lamps, all which will incorporate Autotex technology'.