Rearview Mirror Touch Sensor With Backlit Icon Display
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Solution Overview
Problem
Conventional interior rearview mirror assemblies lack intuitive user input mechanisms that allow for easy control of telematics features, such as hands-free telephone functions, and do not provide clear visual feedback to the user.
Innovation Solution
The integration of touch or proximity sensors behind the reflective element of the mirror assembly, utilizing a backlit sensor element with electrically conductive traces on a transparent substrate to sense user input and provide visual feedback through icons illuminated by a backlighting device, allowing for intuitive control of telematics features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If buttons or user inputs are disposed at the mirror bezel portion, then user control of telematics features is enabled, but the user interface lacks visual feedback and is not intuitively visible to the driver
Solution Approach 1:
The patent uses the reflective element as an intermediary medium to display user interface icons and visual feedback. Instead of placing separate display elements on the bezel, the interface is projected onto the reflective surface itself, allowing the mirror to serve dual purposes: reflection and information display. This resolves the contradiction by providing visual feedback through the existing optical path without adding separate visible components.
Solution Approach 2:
The reflective element is made multi-functional by enabling it to both reflect light for rearview purposes and display user interface icons for telematics control. The same optical surface serves as both a mirror and a display medium, eliminating the need for separate visual feedback mechanisms and improving ease of operation while maintaining visual information delivery.
2Device complexity
If touch sensors are placed behind the reflective element, then the user interface becomes invisible from the front, but this prevents visual feedback to the user
Solution Approach 1:
The reflective element acts as an intermediary that allows light to pass through from the backlighting device and touch sensors positioned behind it, while still maintaining its reflective function. The semi-transparent or selectively transparent properties of the reflective element enable it to transmit backlight to illuminate icons while remaining visible as a mirror from the front, thus resolving the contradiction between sensor placement and visual feedback.
Solution Approach 2:
The reflective element's optical properties are utilized to allow light transmission in specific conditions. When backlighting is activated, the reflective element becomes sufficiently transparent to allow light passage for icon illumination, while in normal conditions it maintains its reflective properties. This dynamic optical behavior enables both sensor integration and visual feedback without compromise.
3Reliability
If electrically conductive traces are made opaque to ensure touch sensing functionality, then touch detection is reliable, but light cannot pass through to backlight the icons
Solution Approach 1:
The electrically conductive traces are segmented into a grid or mesh pattern rather than being continuous opaque lines. This segmentation allows light to pass through the gaps between the trace segments while still maintaining sufficient conductive pathways for reliable touch sensing. The grid structure divides the conductive function into multiple smaller pathways that collectively provide both electrical functionality and optical transparency.
Solution Approach 2:
The electrically conductive traces are made with varying properties in different regions - thinner or more spaced-apart in areas requiring light transmission for icon display, and denser or more continuous in areas requiring enhanced touch sensing reliability. This local variation in trace quality allows simultaneous optimization of both touch detection reliability and light transmission for backlighting.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables intuitive and visually feedback-rich user interaction with telematics features within the rearview mirror assembly, enhancing usability and safety by providing clear visual confirmation of user inputs.
Implementation Method 1
a backlit sensor element that comprises a plurality of electrically conductive traces disposed or established at a transparent or translucent substrate, with the electrically conductive traces being established as a pattern that allows for light emanating from the backlighting device or element to pass through the sensor
Implementation Method 2
backlighting device or element
Implementation Method 3
The touch sensor is disposed behind the mirror reflective element and is operable to sense the presence of a user's finger at or near the front surface of the reflective element and in the vicinity of the touch or proximity sensor
Data Source
AI summary
A vehicular rearview mirror assembly includes a mirror reflective element and a touch sensor device disposed behind a portion of the reflective element and operable to sense the presence of a person's finger at a touch zone of the reflective element proximate to the touch sensor device. A backlighting device is disposed behind the touch sensor device and is operable to backlight a portion of the touch sensor device. The touch sensor device includes a touch sensor substrate having a conductive trace established at a patterned conductive zone of the touch sensor substrate. When the backlighting device is activated, light emanating from the backlighting device passes through the patterned conductive zone of the touch sensor substrate and illuminates an icon so that the icon is viewable through the reflective element by a driver of the vehicle when the rearview mirror assembly is normally mounted at the vehicle.