Display Optical Layers for Under-Screen Sensor Mark Mitigation
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Solution Overview
Problem
Visual defects, such as sensor marks, occur in display devices due to the visibility of underlying sensors like fingerprint sensors through the screen, detracting from user experience and perception of device quality.
Innovation Solution
Implementing a combination of materials and mechanical approaches, including pressure sensitive adhesives with low light reflectance, optical clear adhesives with low elastic modulus, polymer-based layers, metallic layers, and polarizer layers, to mitigate sensor marks while maintaining sensor performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sensor is placed behind a transparent display layer, then the sensor functionality is maintained, but visual defects such as sensor marks become visible through the screen
Solution Approach 1:
The patent introduces spacing elements as intermediary components positioned between the sensor and the transparent display layer. These spacing elements (adhesive layers, polymer layers, metallic layers) act as mediators that prevent direct contact and reduce the transmission of forces that cause sensor marks, while still allowing the sensor to function through the transparent layer.
Solution Approach 2:
The patent applies cushioning layers (adhesive layers with specific thicknesses, polymer-based spacing elements, and metallic layers) in advance before the sensor marks can form. These layers provide mechanical cushioning to absorb and distribute forces, preventing the formation of visible sensor marks through the display screen.
2Object-affected harmful factors
If spacing elements are added between the light source and sensing element, then visual defects are mitigated, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated layers. For example, adhesive layers serve both as bonding agents and as spacing elements; polymer-based spacing elements provide both mechanical support and optical clarity; metallic layers provide both structural integrity and interference patterns to reduce sensor mark visibility. This merging reduces the need for separate components.
Solution Approach 2:
The patent employs composite material structures consisting of multiple layers with different properties (adhesive layers, polymer layers, metallic layers) working together. Each layer contributes specific properties (adhesion, spacing, optical interference, mechanical cushioning) to collectively mitigate sensor marks while maintaining overall device functionality and aesthetics.
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 proposed solutions effectively mask or prevent the formation of sensor marks, enhancing user experience and device retention by improving the visual appearance of display devices.
Implementation Method 1
at least one of the one or more spacing elements including a first pressure sensitive adhesive (PSA) layer having a thickness between 25 and 150 μm and a light reflectance below 10%
Implementation Method 2
at least one of the one or more spacing elements including an optical clear adhesive (OCA) layer or an optical clear resin (OCR) layer, the OCA layer or the OCR layer having an elastic modulus of up to 0.2 megapascals (MPa) and a thickness between 25 and 300 μm
Data Source
AI summary
Various configurations of a display apparatus to mitigate a visual defect is disclosed. Such a visual defect may include a sensor mark that indicates the presence of a sensing element disposed beneath a screen, for instance, shown as edges of a fingerprint sensor, which may be visible to a user and distractive to the user experience. Visual, mechanical, and material properties of one or more layers between the display and the sensing element may be selected to prevent formation of or reduce the visibility of the sensor mark. In some configurations, a low elastic modulus or a low light reflectance material may be used. In some cases, the material may include a black adhesive. In some configurations, a polymer-based or metal-based spacer having a specific thickness may be used. In some configurations, a polarizer layer may be included.