Thin Silicon Substrate Wearable LED Display
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Solution Overview
Problem
Conventional flexible display technologies are limited by their substrates, which restrict their flexibility and scalability, especially in achieving high resolution and pixel density for conformable electronic devices like wearable displays.
Innovation Solution
The development of conformable electronic devices using a silicon substrate with a thickness of 50 μm or less, where an array of LEDs and controller chips are bonded to one side, and a passivation layer is formed on both sides, allowing for conformable behavior and integration into various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If thin glass or plastic substrates are used for flexible displays, then flexibility is improved, but manufacturing precision and structural integrity deteriorate
Solution Approach 1:
The patent changes the substrate material parameter from traditional flexible materials (plastic, thin glass) to silicon substrate with controlled thickness (50 μm or less). This parameter change maintains flexibility while providing superior structural integrity and enabling high-resolution LED integration that is not achievable with conventional flexible substrates.
2Adaptability or versatility
If silicon substrate thickness is reduced to 50 μm or less, then conformability is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent employs a thin silicon substrate (50 μm or less) that functions as a flexible shell, enabling the display to conform to curved surfaces and wearable applications. The thin film structure provides sufficient conformability while the silicon material itself maintains adequate mechanical strength through its inherent material properties.
Solution Approach 2:
The patent creates a composite structure by bonding LED arrays and controller chips to the silicon substrate, forming an integrated display assembly. This composite construction distributes mechanical stresses across multiple components, enhancing the overall mechanical strength while preserving the conformability of the thin silicon substrate.
3Manufacturing precision
If high pixel density is achieved with small LED size, then resolution is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The patent applies local quality optimization by positioning LEDs within recessed bank structures etched into the silicon substrate. This localized structural modification allows small LEDs to maintain adequate light extraction efficiency by providing light-trapping surfaces and reducing total internal reflection, while still achieving high pixel density through the compact arrangement.
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
This configuration enables high-resolution, high-pixel-density displays with improved flexibility and scalability, suitable for wearable and flexible product integration without compromising light extraction efficiency or structural integrity.
Implementation Method 1
the silicon substrate is sufficiently thin to exhibit conformable behavior
Implementation Method 2
A first passivation layer is formed over the array of LEDs and the array of controller chips on the first side of the silicon substrate. A second passivation layer is formed over a second side of the silicon substrate
Implementation Method 3
the silicon substrate is at or close to a neutral (strain) axis in a conformable electronic package. In such a configuration, where the conformable electronic package is rolled or bent, one surface is under tensile strain while the opposite surface is under compressive strain
Data Source
AI summary
A conformable electronic device and methods for forming such devices are described. Embodiments of a conformable electronic device may include a silicon substrate having a thickness of 50 μm or less. An array of LEDs that are electrically coupled to a controller chip may be formed on a surface of the silicon substrate. In an embodiment, a top passivation layer is formed over the array of LEDs, the one or more controller chips, and the top surface of the silicon substrate. An embodiment also includes a bottom passivation layer formed on a bottom surface of the silicon substrate.