OLED Light Shielding Layer Positioning for Leakage Control
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Solution Overview
Problem
Organic light-emitting diodes (OLEDs) with light-emitting units on a substrate's surface face issues with light leakage in oblique directions, which can compromise their functionality, especially when viewed from certain angles.
Innovation Solution
Incorporating a light shielding layer in the OLEDs with a specific configuration where the end of the light shielding layer of each light-emitting unit is positioned outside the unit's end by a calculated distance, ranging from d×tan(arcsin(sin θL/ns) to 3d×tan(arcsin(sin θL/ns)), to prevent light leakage while maintaining high light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light-emitting units are provided on the first surface side of the substrate, then light can be emitted from the light-emitting units, but light leaks out from the first surface side of the substrate in oblique directions
Solution Approach 1:
A light shielding layer is introduced as an intermediary element between the light-emitting unit and the first surface of the substrate. This layer selectively blocks oblique light rays while allowing the light-emitting function to continue, thus mediating between light emission and light leakage prevention
Solution Approach 2:
The light shielding layer extends beyond the boundaries of the light-emitting unit in the lateral dimension, creating an overlapping region that blocks oblique light paths. By adding this dimensional extension, the patent prevents light leakage without affecting the vertical light emission function
2Object-generated harmful factors
If the light shielding layer is positioned to prevent light leakage, then light leakage is reduced, but the structural complexity and manufacturing precision requirements increase
Solution Approach 1:
The patent specifies a quantitative range for the overlapping distance (d×tan(arcsin(sin θL/ns)) to 3d×tan(arcsin(sin θL/ns))), transforming the qualitative requirement of 'sufficient overlap' into a measurable parameter range that guides manufacturing while ensuring effective light leakage prevention
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
Effectively prevents light leakage from the light-emitting units towards the first location, ensuring reliable performance and high transmittance by strategically positioning the light shielding layer relative to the light-emitting units.
Implementation Method 1
each light-emitting unit including a light shielding layer... an end of the light shielding layer of the first light-emitting unit on the first location side is located outside an end of the first light-emitting unit by equal to or greater than d×tan(arcsin(sin θL/ns))... effectively prevents light leakage from the light-emitting units towards the first location
Data Source
AI summary
An end (that is, an end (130b)) of a second electrode (130) of a k-th light-emitting unit (152(k)) on a second side (S2) exists on the outer side of an end (152b) of the k-th light-emitting unit (152(k)) by the width WR(k) of an overlapping region (OR). In one example, the width WR(k) is equal to or greater than d×tan(arcsin(sin θl(k)/ns)) and equal to or less than 3d×tan(arcsin(sin θl(k)/ns)) (d×tan(arcsin(sin θl(k)/ns))≤WR(k)≤3d×tan(arcsin(sin θl(k)/ns))).