Modern Automotive Display Touch-Lens Interface: Page 3 of 5

December 13, 2012 //By Paul Weindorf, James Kornacki, Visteon Corporation
Modern Automotive Display Touch-Lens Interface
The center stack panel area of today’s vehicles has become the integration site for many occupant interface technologies and is being driven by consumer requirements influenced by today’s personal electronic devices.
the reflection level of the display opening versus the non-display area to minimize the contrast (also known as Michelson contrast, Cm) while maximizing display visibility. There are many interrelated factors to consider when selecting the lens optical configuration, such as transmission, polarization, retardation, display luminance and reflected background luminance. Since reflections can be used beneficially to hide the display opening, the lowest reflection lens configuration may not always be the best solution.

Taking the visibility mathematical function into account, various optical configurations may be examined to ascertain the required display luminances. Figure 6 shows that lower display luminances (higher optical system efficiencies) can be achieved with different optical other than the traditional neutral density filter (ND). However, the background reflection level must be considered to pick the best optical configuration based on actual in-vehicle jury evaluations.

Minimizing Fingerprint and Reflections:

Another consideration for front lens aesthetics is the use of antiglare (AG) films to lessen the effect of fingerprints and reduce the clarity of specular reflections. AG films must be used with caution due to unwanted speckle and decreasing the sharpness of the TFT image (Figure 7) as the film is moves further from the TFT.

 

Figure 7: AG Film Blurring the TFT Image

 

The blurring performance of AG films may be quantitatively determined by obtaining the line-spread-function and associated modulation transfer function via FFT techniques [1].

Performance & Conformance

Display Visibility:

One of the challenges is to ensure vehicle center display visibility under all lighting conditions. Visibility problems occur when engineering principles coupled with human factor studies are not properly applied. The fundamental geometric requirement is that the display must be positioned and tilted so no window can be seen in a mirror placed on the display surface. If a window can be seen, a potentially unsafe specular sunlight condition could result in increased driver recovery time and possible retinal damage from seeing the sun's reflection. No

Design category: 

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