Segmented Mirror Surface for Accurate Capacitive Touch Sensing
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Solution Overview
Problem
Existing mirror devices with capacitive touch controllers face challenges in replicating the mirror experience due to cross-talk issues and the unsuitability of metallic reflective layers with capacitive sensors, which affect the accuracy and responsiveness of touch inputs.
Innovation Solution
A capacitive touchscreen mirror device is designed with a reflective metal layer divided into electrically isolated metal islands, allowing capacitive sensors to detect touch inputs accurately by minimizing electrical charge dissipation and enabling cross-talk between adjacent islands for improved sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a continuous metallic reflective layer is used, then the mirror surface quality is improved, but capacitive sensor functionality is negated due to electrical conductivity
Solution Approach 1:
The continuous metallic reflective layer is divided into separate metal islands that are electrically isolated from each other. This segmentation allows the metal layer to maintain its reflective properties while preventing electrical charge dissipation across the entire surface, thereby enabling capacitive sensor functionality to operate correctly.
2Reliability
If trench widths are increased to minimize cross-talk between touch pads, then cross-talk is reduced, but the visual appeal of the mirror surface is detracted and only static touch controls are allowed
Solution Approach 1:
The patent applies different properties to different regions: metal islands provide reflectivity and are positioned to minimize cross-talk, while the gaps between islands are optimized for capacitive sensing. This local differentiation allows the system to achieve both cross-talk minimization and maintained visual appeal with dynamic control capabilities.
3Illumination intensity
If a metallic reflective layer is used, then the mirror function is achieved, but touch input accuracy deteriorates due to electrical charge dissipation
Solution Approach 1:
By segmenting the metallic layer into isolated islands, the patent prevents electrical charge dissipation that would occur with a continuous layer. Each metal island maintains localized electrical properties, thereby improving touch input accuracy while preserving the mirror function through the reflective surfaces of the islands.
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
The solution enhances the accuracy and responsiveness of touch inputs by isolating metal islands, reducing cross-talk, and maintaining a mirror-like appearance, while allowing for dynamic and flexible control options.
Implementation Method 1
Capacitive sensors at different sensor positions may be associated with their respective nearest metal islands, typically the island having the strongest capacitive coupling with the sensor at that position
Implementation Method 2
The mirror surface comprises a reflective metal layer divided across the mirror surface in separate metal islands
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3C
AI summary
Touchscreen mirror device (100) comprising a touchscreen panel (10) and a mirror surface (20). The touchscreen panel (10) comprises a grid of capacitive sensors (12) for detecting a position of an input object such as a fingertip (F) near the touchscreen panel (10). The mirror surface (20) is configured to at least partially reflect a mirror image (M) at a front side of the mirror surface (20). The mirror surface (20) comprises a reflective metal layer (21) divided in separate metal islands (21a,21b) that are electrically isolated from each other by a single contiguous gap (G) for allowing the capacitive sensor (12) to detect a position of the input object through the mirror surface (20).