LED Backplane Optics for Higher Light Extraction
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Solution Overview
Problem
Existing display technologies face challenges in efficiently extracting light from light-emitting diode (LED) chips, leading to low light extraction efficiency and high power consumption, while also being costly due to the use of extensive encapsulating adhesives.
Innovation Solution
A backplane design that includes a substrate with a circuit structure layer, a first reflective layer with through holes for LED chips, and optical structures with curved light exit surfaces, which are formed through a dispensing process to enhance light extraction and reduce adhesive usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional flat encapsulating adhesive structures are used, then manufacturing is simple, but light extraction efficiency is low due to total internal reflection
Solution Approach 1:
The patent applies curvature by forming the encapsulating adhesive into a convex lens shape with a curved surface instead of a flat surface. This curvature changes the angle of light incidence at the adhesive-ambient interface, reducing total internal reflection and improving light extraction efficiency while maintaining manufacturing simplicity through dispensing processes.
2Reliability
If extensive encapsulating adhesive is used to protect LED chips, then protection and stability are improved, but production cost increases
Solution Approach 1:
The patent segments the encapsulating adhesive into individual convex lens structures for each LED chip rather than using a continuous layer. This segmentation reduces the total adhesive quantity needed while maintaining protection and stability, as each lens is precisely formed only where needed around the LED chip.
Solution Approach 2:
The patent uses thin film structures for the encapsulating adhesive in the form of convex lenses that provide adequate protection with minimal material. The flexible lens shape allows effective coverage of the LED chip with reduced adhesive volume compared to traditional thick flat encapsulation.
3Ease of manufacture
If flat encapsulating adhesive is used, then manufacturing process is simple, but power consumption is high due to low light extraction efficiency
Solution Approach 1:
The convex lens shape of the encapsulating adhesive optimizes light extraction by reducing total internal reflection at the interface. This improves the efficiency of light emission from LED chips, thereby reducing the power consumption required to achieve the same luminous output, while the dispensing process keeps manufacturing simple.
4Loss of energy
If curved surface optical structures are formed, then light extraction efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent implements curved surface optical structures in the form of convex lenses on the encapsulating adhesive. These curved surfaces improve light extraction efficiency by altering light propagation angles and reducing total internal reflection, while the overall device complexity remains manageable through standard dispensing and curing processes.
Solution Approach 2:
The dispensing process forms the convex lens shapes self-organizingly as the adhesive material is deposited and cured. The material naturally forms the curved surface structure during the dispensing and drying process, reducing the need for complex post-processing or additional manufacturing steps to create the optical structures.
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 solution improves light extraction efficiency by reducing total reflection and increasing the amount of light exiting normally, while also reducing production costs by minimizing the use of encapsulating adhesives and enhancing the stability and protection of LED chips.
Implementation Method 1
A light exit surface of the optical structure is a curved surface... increasing the amount of light exiting normally
Implementation Method 2
The first reflective layer is disposed on a bearing surface of the substrate... The first reflective layer includes a plurality of through holes spaced apart
Data Source
AI summary
A backplane includes: a substrate including a circuit structure layer and a second reflective layer, a first reflective layer disposed on a bearing surface of the substrate, a plurality of light-emitting diode chips, and a plurality of optical structures. The first reflective layer includes a plurality of through holes spaced apart. A light-emitting diode chip in the plurality of light-emitting diode chips is located in a through hole. The plurality of light-emitting diode chips are electrically connected to the circuit structure layer. The circuit structure layer is configured to drive the plurality of light-emitting diode chips to emit light. An optical structure in the plurality of optical structures covers the light-emitting diode chip, a light incident surface of the optical structure is in contact with a light exit surface of the light-emitting diode chip, and a light exit surface of the optical structure is a curved surface.