The German company Preh uses a PLEXIMID® material to develop a touch screen that is aided by tactile positioning to make the touch screen easier to use and is currently used in BMW 5 Series and 7 Series 4-zone air conditioners.
In just a few years, touch screens have increasingly replaced many of the knobs and buttons previously used in operational controls, as has been the case in the automotive industry, but the challenge with touchscreens in automotive applications is driving The crew must be able to operate various functions integrated in the center console, such as air conditioning and infotainment systems, with the eyes off the road. "Knobs and buttons allow the driver to accurately sense which of their hands are on the control unit Location, "explains Hans Karl Heil, mechanical design and development engineer at Preh," but with a touch screen this is obviously not possible. "So this operating system specialist in Bad Neuenahr-St-Saale, Germany designed Many concepts to make it easier for the driver to operate the touch screen.
An easy-to-use touch screen made of PLEXIMID® is currently used in the BMW 5 Series and 7 Series 4-Zone air conditioners
Tactile surface contour
Preh Corporation has developed a whole new generation of haptic surface contours for the central stack operating system's air-conditioning capabilities, a special feature BMW provides to consumers purchasing BMW 5 Series and 7 Series' slightly indented surfaces, Making it easier to handle. "Heil said the positioning aid is integrated into the touchscreen film made of thermoplastic PLEXIMID® TT50 material, a PMMA material with high thermal deformation temperature provided by Evonik , But also for light pipes such as daytime running lights in modern LED headlamps. "In addition to having good optical properties, this material provides very precise mold surface reproducibility, making it a three-dimensional The ideal material for forming, "said Heil." It is important that we simply mold the parts to meet the mass production needs of the automotive industry. "
PLEXIMID® also meets many other requirements in the automotive industry. "Automotive interiors are vulnerable to permanent wear and therefore all materials used must be able to withstand these pressures." Explains Lukas Dössel, Ph.D., PMMC Global Product Management. ® exhibits high chemical resistance, which means it is insensitive to sweat, creams and foods, and the like, in the hands of the operating system because, like PMMA, PMMI does not have the highest levels of any thermoplastics Of the surface hardness does not cause any problem even if subjected to the mechanical stress caused by the key or the handbag.In particular, Preh Company has adopted a special coating to provide extra protection for the material.
High heat distortion temperature
With its high heat deflection temperature, PLEXIMID® is also able to withstand the heat build-up in cars parked in the sun, which can easily reach temperatures above 100 ° C. Low thermal expansion is another key point when choosing materials because We attach the touch screen film to the back of the silicate glass display, so that the cover must show minimal expansion when the temperature fluctuates.
Unified design and function
The display on the operating elements is clearly visible even in the case of light exposure, explains Dr. Dössel, PMMI expert at Evonik: 'There is no other plastic with a high heat deflection temperature that shows such a low double Refraction, which means almost no disturbing color reflections. "This display can even be read by people wearing polarized sunglasses, and for this reason PLEXIMID® materials, along with Preh's high-tech operating system, are designed for safe driving And achieved a successful combination.
Preh, based in Bad Neustadt an der Saale, Germany, is a specialist operating system company that has designed many concepts that make it easier for the driver to operate the touch screen