Digitizer Adhesive Layers for Foldable Display Viewability
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Solution Overview
Problem
Electronic apparatuses face challenges in achieving reliable detection of external inputs and maintaining viewability and folding properties, particularly in display devices with complex adhesive layer structures.
Innovation Solution
The electronic apparatus incorporates a digitizer with a specific adhesive layer configuration, including first and second adhesive layers with controlled storage moduli and sub-adhesive layers, which are fully cured to enhance adhesion and folding reliability, along with a shielding layer for improved input detection and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive layers are used to bond the digitizer to the display panel, then adhesion strength is improved, but surface flatness deteriorates
Solution Approach 1:
The patent changes the physical-chemical parameters of the adhesive layer by controlling its storage modulus within a specific range (0.01-5 MPa at -20°C) and thickness (10-50 μm). These parameter optimizations allow the adhesive layer to maintain adequate bonding strength while minimizing surface irregularities, thus resolving the contradiction between adhesion strength and surface flatness.
2Reliability
If multiple adhesive layers are used to enhance bonding, then adhesion reliability is improved, but device complexity increases
Solution Approach 1:
The patent segments the adhesive system into multiple functional layers: a first adhesive layer with storage modulus of 0.01-5 MPa for primary bonding, and sub-adhesive layers with lower storage modulus (0.01-1 MPa) for stress distribution and surface flattening. This segmentation allows each layer to perform its specific function optimally, improving overall reliability while maintaining manageable complexity through clear functional differentiation.
3Strength
If adhesive layers with higher storage modulus are used, then bonding strength is improved, but folding flexibility deteriorates
Solution Approach 1:
The patent optimizes the storage modulus parameter of the adhesive layers to fall within 0.01-5 MPa at -20°C, which is a relatively low range compared to conventional adhesives. This parameter change enables the adhesive to provide sufficient bonding strength for display assembly while maintaining high flexibility and elasticity that accommodate repeated folding operations without cracking or delamination.
4Strength
If the digitizer is closely bonded to the display panel, then structural integrity is improved, but viewability deteriorates
Solution Approach 1:
The patent controls the thickness of the adhesive layer within 10-50 μm, which is a optimized range that provides sufficient bonding strength for structural integrity while minimizing the optical path distance that light must travel through the adhesive. This reduces light scattering and absorption in the adhesive layer, thereby maintaining high viewability and display brightness.
Data Source
AI summary
Provided is an electronic apparatus including a window, a display panel disposed below the window, a digitizer disposed below the display panel and including a first surface and a second surface opposing the first surface, a first adhesive layer disposed on the first surface, and a second adhesive layer disposed below the second surface, wherein the first adhesive layer and the second adhesive layer are two-time-cured. Accordingly, an electronic apparatus having improved folding and viewability properties may be provided.