Head-up displays for in-car navigation systems are starting to add some value to one of the oldest plastic components in cars - the protective barrier in the windshield.
The displays, which rely on a specially designed polyvinyl butyral layer between the two sheets of glass that make up the windshield, focus on a projected image indicating future turns as well as the car's current speed or engine problems.
With European and Asian carmakers adding the displays in future-model cars, PVB suppliers are starting to see an increased demand for specialized versions of their film.
``We are talking to our customers globally and seeing [requests for quotes] that show that customers are interested,'' said Bert Wolfram, vice president for Siemens VDO AG North American information systems for passenger cars.
General Motors Corp. launched the head-up display for its Cadillac division more than five years ago. The early system projected key information, such as speed and engine warnings, from the standard instrument panel cluster up onto the windshield, where drivers could see them without looking away from the road.
Carmakers' use of the system was stagnant, though, until this year, when firms such as Germany's BMW AG and Toyota Motor Corp.'s Lexus brand began offering them.
Currently, the system is used on a few hundred thousand cars per year. PVB supplier Solutia Inc. anticipates the number of cars with the program could top 1 million by 2008 and potentially hit 4 million by 2010.
The breakthrough came with improvements to the display itself, as well as the increasing information available to drivers. BMW's 5 and 6 Series vehicles make it available along with a navigation system. The display does not show the entire map, but does indicate key turns ahead, so drivers do not have to look down to view the information from a center console, Wolfram said Aug. 4 in a telephone interview.
``There's more and more feature content in the cars,'' he said. ``Many of them need a way to display that information and not distract the driver from the road.''
PVB has been used in windshields for more than 50 years as a safety measure, keeping them from breaking into small pieces. But thanks to reformulations that allow it to go into other windows and add features such as acoustic and sun protection - and now the increasing interest in head-up displays - film suppliers have access to a wider range of customers, who are paying more for a wider range of additional features.
For a head-up display - or HUD - the layer has to be specially designed to be thicker at the bottom and narrower at the top to focus a projected image from the instrument panel. The exact angle depends on the car, said Rick Williams, technical team leader for Solutia's Saflex PVB unit.
The display appears to hover before the driver's eyes, provides its information in a variety of colors and is visible day and night.
``The [PVB] provides the whole optical element of the head-up display,'' Wolfram said.
By fine-tuning both the displays and the PVB angle, Siemens has even been able to create an HUD that can adjust the height of the display for different drivers of different heights using different seat adjustments.
And since each car using the system has its own windshield shape and curve, they require a unique PVB layer, according to Tom Laboda, Solutia's automotive market development manager for films. That opens the window for the company to offer other value-added elements to the layer.
Solutia already has one order for a future vehicle that combines an HUD element with an acoustic barrier that cuts down on outside noise.
The film also requires special packaging. PVB is made in massive rolls at places like Solutia's Trenton facility. An HUD layer is twice the size on one end than the other, making it more difficult to ship.
But PVB suppliers are anxious to see specialized sales take off and, along with them, more features that can increase the film's overall value.
