Cost is not the only thing that keeps head-up display (HUD) units limited to large and luxury cars. Installation space is another prime reason these units have not made their way down the automotive food chain. Attacking these challenges together, Siemens VDO created a modular HUD design it claims is roughly half the cost and size of current units, and one that—unlike its predecessors—allows drivers of differing heights to adjust the virtual image to suit their preferences by tilting the mirror that projects that image.
Because the unit is modular, installation requirements and system costs can be adapted to meet the requirements of a particular model by altering the number of mirrors, display colors, and illumination elements. For smaller vehicles an OEM might select a variant with only two mirrors and one lens. Information would be transmitted from a thin-film transistor to the windshield through a magnifying lens that guarantees the image is of the proper size and sharpness. Displayed in a horizontal format, the image spans a volume of 9 cm by 20 cm, but with increased resolution, color contrast, and greater color scheme variability. This unit also could be used to display other images, including those from a night vision system.