Looing for yet another way to “own” the automotive infotainment segment , the Bosch Group's Car Multimedia Division this week introduced what it calls a combiner heads-up display technique that will safetly flash crticial driver information in textual form into a projected image in the driver's field of vision out the front windshield.
Its first customer is BMW Group, which has chosen it to use in a number of its next generation automobiles, starting with the new MINI Hatch..
According to Manfred Baden, President of the Car Multimedia division at Bosch. the system belongs to the so-called “combiner” category of head-up displays. The image they generate is combined with the scenery outside the vehicle in such a way that makes them appear to merge with one another at a distance of around two meters in front of the vehicle (see below ) .
The system does not project the information onto the windshield but instead onto a small special plastic screen placed before it. The new head-up system is therefore completely self-contained and can be fitted to various types of vehicle without any major technical modification necessary. The displayed information is invisible to the front passenger.
Head-up displays present information directly in the driver's field of vision, he said, where details like the current speed, navigation recommendations and warnings appear as if suspended in mid-air in front of the vehicle. This has a relieving effect on the driver's vision since the eyes have to refocus less often. “The driver does not need to constantly switch between looking at the instrument panel and looking at what is happening on the road,” explains Baden.
One of the quality characteristics of this new combiner head-up display he points to is that the approach they have taken creates a display with information that remains sharp and distortion-free even when the driver's head moves.
This is achieved through the use of a plastic “combiner” screen, which has an aspheric surface. “The tolerance specified for the front surface is extremely tight,” he said. “The edge of the screen has been milled in such a way to make it level with the driver's line of sight, which means it becomes invisible to the driver, causing the displayed information to merge with the background.
Part of a self-contained module that can be fully integrated in the instrument panel, the plastic “combiner” screen is driven by a variable-speed electric motor to extend it out of the box when needed. When the system is switched off, the screen fully retracts into the box.
The imaging unit is equipped with a full-color liquid crystal display (LCD) with a resolution of 480 by 240 pixels. Similar to a photographic slide, it is lit by a single light emitting diode with a high light intensity. The light signal bounces via folding mirrors to the display unit, whose key component is the “combiner” screen.
This projects the image into the so-called “eye box”, the region in which the driver's eyes are situated. The angle of the “combiner” screen can be fine-tuned to suit the driver's height, and the brightness of the displayed information is adjustable by way of sensors or a dimmer wheel. “This new head-up display enables us to reduce the burden on the driver and so make car driving even safer and more comfortable,” said Baden.