Touch Screen Display Uniformity via Dummy Electrode Masking
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Solution Overview
Problem
Touch screens with non-uniform spacing between common electrode segments can create visible breaks in the conductive material, leading to non-uniformities in the appearance of the display area, making the touch circuit pattern noticeable to users.
Innovation Solution
The implementation of 'dummy' features on a separate layer, such as primary-dummy features at gaps and supplementary-dummy features uniformly spaced, to mask the breaks and create a more uniform appearance, with the latter increasing spatial frequency and correcting non-uniform spacing to minimize visibility of the touch circuit pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gaps are introduced between Vcom segments to enable touch sensing and image display, then touch sensing functionality is achieved, but the breaks become visible and create non-uniformities in the appearance of the viewable display area
Solution Approach 1:
Dummy features are introduced as intermediary elements on the pixel layer to mask the visible breaks between Vcom segments. These dummy features occupy the area above the gaps without interfering with touch sensing functionality, thereby mediating between the need for functional gaps and the desire for visual uniformity
Solution Approach 2:
The dummy features are designed to match the optical properties of the surrounding Vcom segments, making them visually indistinguishable. By matching the transparency and optical characteristics, the dummy features blend seamlessly with the display background, eliminating visual non-uniformity
2Object-affected harmful factors
If dummy features are added to mask gaps and improve visual uniformity, then appearance uniformity is enhanced, but device complexity increases due to additional layer modifications
Solution Approach 1:
The dummy features serve multiple functions simultaneously: they mask visual breaks between Vcom segments, maintain optical uniformity across the display, and do not interfere with touch sensing operations. This multi-functionality justifies the added complexity by delivering multiple benefits from a single structural modification
Solution Approach 2:
The solution addresses the visual uniformity problem by operating on a different layer (pixel layer) rather than modifying the Vcom layer itself. By placing dummy features on the pixel layer above the gaps, the solution works in another dimensional space, avoiding direct modification of the conductive material structure
Data Source
AI summary
Improvement of visual uniformity of an integrated touch screen display is provided. A touch screen can include common electrodes separated by gaps in a Vcom layer. To improve visual non-uniformity in the display resulting from the gaps, a first set of semi-transparent dummy features (primary-dummy features) can be formed on a second layer at the locations of the gaps, and a second set of dummy features (supplementary-dummy features) can also be formed on the second layer or another layer to mitigate low spatial resolution of the primary-dummy features and/or non-uniform spacing of the primary-dummy features. In some examples, holes or slits can be formed in the Vcom layer at areas of the supplementary-dummy features to further improve visual uniformity.