Spatial recognition is a new feature gaining popularity and offers some unique challenges to the touch-lens. If the requirements are simple driver vs. passenger hand detection, projected capacitance solution may suffice. However, for more complex gestures and larger detection areas above the panel, IR LED reflection, or possibly IR camera technologies are warranted. This solution requires the use of an IR transmissive surface. Other technology used to recognize no-touch movements (such as ultrasound), may result in a decreased craftsmanship level (visible microphone openings).
Hiding of the display behind the continuous curved surface that provides partial or complete display hiding provides a high craftsmanship appearance that is a trend in the automotive space (example in Figure 4).
Figure 4: Dead-front example
This exciting styling opportunity gives the Tier 1 supplier or system integrator one of the biggest challenges in the center stack of the vehicle. Addressing this challenge requires the following:
- The ability to quantitatively assess visibility of the display for a given optical system and vehicle packaging
- Optimizing the design of the optical system
- Providing the best combination of display and efficient backlight
Providing a dead-front or black panel appearance requires an understanding of how the human eye works to optimize the light transmission while providing the desired hiding effect. Hiding the display opening when the display is off involves human factor studies. The contrast sensitivity function (CSF) per Figure 5 shows that a contrast of about 0.01 is necessary to hide the display opening.
Figure 5: Contrast Sensitivity Function
Using the CSF as a guide, different optical constructions may be considered to control