- to a proportion of users who are sensitive to the wavelength of the touchpad’s laser backlight; and
- most important of all, expensive.
Nevertheless, this type of steering wheel-mounted, thumb-operated touchpad appeals strongly to users: it is intuitive, safe, sleek in appearance, and robust, since unlike a conventional mechanical button, it contains no moving parts.
And the implementation of a touchpad allows the car maker to perform a thorough decluttering of the driver controls and user inputs. In luxury and premium vehicles, which are loaded with many user-selectable features and functions for comfort, driving style, infotainment and so on, the use of single-function mechanical switches and buttons can lead to a proliferation of user input devices on and around the steering wheel.
By replacing multiple conventional buttons with a single touchpad for selecting choices in a software menu, the car maker can improve the steering wheel’s appearance, eliminate the risk of mechanical failure inherent in a conventional button, and make the user interface far simpler and easier for the driver to use.
Now car manufacturers are evaluating methods for achieving this reliably, with a compact solution which has a lower cost than OFN.
Combining capacitive sensing with force and haptics
In collaboration with automotive system suppliers, Synaptics has been developing system designs which will enable the implementation of proven, compact and responsive capacitive sensing touchpads without suffering from the problem of inadvertent touch events. Extensive user testing of prototypes shows that capacitive-based force sensing allied with capacitive touch sensing, and backed by haptic feedback, provides exactly the right combination of a responsive feel with total control over the selection of items in a software menu.
The addition of force sensing means that the user is required to actively press the touchpad to activate a function in the menu system. When the system registers a press, it confirms this back to the driver with haptic feedback – typically a short vibration of