Display Pixel Structure With Separate Reflector to Avoid Oxide Isolation
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Solution Overview
Problem
The challenge in micro display IC chips is the formation of a native oxide layer on the bottom electrode/reflector, which is dielectric and causes electrical isolation, leading to manufacturing yields and optical performance issues due to the reactivity of common metals with oxygen.
Innovation Solution
The solution involves a separate bottom electrode and reflector with a coupling structure extending from the bottom electrode to the light emission device, allowing for electrical coupling independent of the reflector, and choosing materials with low oxygen reactivity for the bottom electrode and conductive native oxide to prevent electrical opens while maintaining high reflectivity for the reflector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a common metal (e.g., aluminum) is used for the bottom electrode/reflector, then high reflectivity is achieved, but the metal reacts with oxygen to form a dielectric native oxide layer causing electrical isolation
Solution Approach 1:
The bottom electrode and reflector are divided into two separate components. The bottom electrode is made of a conductive material (e.g., ITO, transparent conductive oxide) that maintains electrical conductivity even when oxidized, while the reflector is made of a highly reflective material (e.g., aluminum, silver) that can form dielectric oxide layers without compromising the electrical function. This segmentation allows each component to be optimized for its specific function without the trade-off present in the integrated design.
Solution Approach 2:
A coupling structure is introduced as an intermediary component between the bottom electrode and the light emission device. This coupling structure provides the electrical connection path, allowing the bottom electrode to remain electrically functional even when the reflector forms a dielectric oxide layer. The coupling structure mediates the electrical coupling function that would otherwise be compromised by the oxide layer on the integrated electrode-reflector structure.
2Ease of manufacture
If the bottom electrode and reflector are integrated as one component, then manufacturing is simpler, but the dielectric native oxide layer causes electrical opens and reduces manufacturing yields
Solution Approach 1:
By segmenting the integrated electrode-reflector into separate bottom electrode and reflector components, the patent eliminates the electrical open problem caused by oxide layer formation. Although this increases structural complexity, it resolves the manufacturing yield issue by preventing the formation of non-functional electrical connections, thereby improving overall productivity and reducing waste.
Solution Approach 2:
The coupling structure serves as an intermediary that ensures reliable electrical connection between the bottom electrode and the light emission device. This intermediary component guarantees functional electrical coupling regardless of the oxide layer status of the reflector, thereby ensuring high manufacturing yields and reducing the occurrence of electrical opens in mass production.
3Reliability
If a separate bottom electrode and reflector with coupling structure are used, then electrical coupling is maintained despite oxidation, but device complexity increases
Solution Approach 1:
The bottom electrode is designed to serve multiple functions: it provides electrical conductivity for the device operation and simultaneously acts as a reflective surface for light. By making the bottom electrode multi-functional, the patent reduces the need for additional complex structures in some configurations, thereby mitigating the increase in device complexity while maintaining reliable electrical conductivity.
Solution Approach 2:
The coupling structure is designed to replicate or extend the functionality of the traditional integrated electrode-reflector interface. By creating a separate coupling structure that mirrors the electrical connection function, the patent maintains simplicity in the electrical connection approach while allowing the reflector and bottom electrode to be optimized separately for their respective functions.
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 approach enhances manufacturing yields and optical performance by preventing electrical opens and ensuring high reflectivity, even with materials that oxidize, thereby improving the bulk manufacturing process.
Implementation Method 1
a coupling structure extending from the bottom electrode, alongside the reflector, to an interface between the light emission device and the reflector to electrically couple the bottom electrode to the light emission device
Implementation Method 2
a reflector bordering the bottom electrode... ensuring high reflectivity
Data Source
AI summary
Various embodiments of the present disclosure are directed towards an integrated circuit (IC) chip comprising a display pixel in which a bottom electrode and a reflector are separate and border. A light emission device overlies the reflector, and a top electrode overlies the light emission device. A coupling structure extends from the bottom electrode, alongside the reflector, to an interface between the light emission device and the reflector to electrically couple the bottom electrode to the light emission device.