Display Device Spacer for Shadow Reduction
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Solution Overview
Problem
Display devices face challenges in maximizing the transmission area while minimizing the non-display area, particularly due to the shadow phenomenon that occurs when depositing counter electrodes using a fine metal mask, which reduces light transmittance and affects the performance of sensors and display pixels.
Innovation Solution
Incorporating a spacer made of organic materials like polyimide, polyamide, or acrylic resin around the boundary regions between transmission portions and counter electrodes to prevent the shadow phenomenon, ensuring effective light transmittance and electrical connectivity between counter electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine metal mask is used to deposit counter electrodes, then manufacturing precision is improved, but the shadow phenomenon occurs which reduces light transmittance and worsens the performance of transmission portions
Solution Approach 1:
The counter electrode structure is segmented into multiple parts: a first counter electrode in the display area, a second counter electrode in the sensor area, and a bridge counter electrode connecting them. This segmentation allows the bridge counter electrode to be positioned away from the transmission portion, preventing shadowing while maintaining electrical connectivity between the display and sensor areas through the substrate.
Solution Approach 2:
The substrate acts as an intermediary to provide electrical connection between the first and second counter electrodes. Instead of using a bridge counter electrode that would cast shadows, the substrate serves as the conductive path, eliminating the shadow phenomenon while maintaining electrical continuity across the display device.
2Area of stationary object
If the transmission portion area is increased, then sensor performance is improved, but the shadow phenomenon from counter electrodes becomes more significant
Solution Approach 1:
By segmenting the counter electrode structure into separate first and second counter electrodes with a bridge portion, the design allows the transmission portion area to be maximized while the bridge counter electrode is positioned to minimize shadowing effects on the enlarged transmission areas.
Solution Approach 2:
The bridge counter electrode is positioned in the thickness direction above the substrate, utilizing the third dimension to route the connection path away from the plane of the transmission portions, thereby reducing shadowing while maintaining electrical connectivity.
3Device complexity
If sensors are disposed below the display panel, then device complexity is reduced, but the shadow phenomenon affects the transmission portions and sensor area
Solution Approach 1:
The display device is segmented into distinct display area and sensor area with separate counter electrodes for each, allowing the sensor area to be optimized for light transmission while the display area maintains its display function, thus reducing overall device complexity while preventing shadowing effects.
Data Source
AI summary
A display device includes: a substrate including a display area including a plurality of first pixels and a sensor area including a plurality of second pixels and a plurality of transmission portions, a plurality of first counter electrodes disposed corresponding to the plurality of first pixels, respectively, a plurality of second counter electrodes disposed corresponding to the plurality of second pixels, respectively, and a spacer disposed to overlap at least a portion of a boundary region between a transmission portion of the plurality of transmission portions and a second counter electrode of the plurality of second counter electrodes, which are adjacent to each other.