Shared-Layer LED Electrode Layout for Fine-Pitch Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light emitting devices with shared n-type, p-type, and active layers face challenges in reducing the distance between electrodes, making it difficult to achieve fine pitches necessary for high-resolution displays due to limitations in patterning techniques like wet etching and lift-off processing.
Innovation Solution
A light emitting device design featuring a single continuous n-type, p-type semiconductor layer, and contact electrode film shared among multiple elements, with strategically controlled sheet resistance and oxygen concentration in the contact electrode film to facilitate fine patterning using dry etching, allowing for closer electrode spacing and reduced pitch between light emitting areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet etching or lift-off processing is used to form electrodes on the p-type layer, then the processing is simpler and avoids dry etching complexity, but the electrode distance cannot be shortened and fine patterns cannot be formed
Solution Approach 1:
The patent changes the material parameter of the contact electrode film to ITO or IZO, which have specific properties that enable both easy processing and fine pattern formation. By selecting materials with appropriate oxygen concentration and sheet resistance characteristics, the patent achieves fine electrode patterns while maintaining manufacturing simplicity.
Solution Approach 2:
The patent uses composite material structures by combining ITO or IZO contact electrode film with the p-type semiconductor layer. This composite structure allows the contact electrode film to serve dual functions: facilitating easy electrode formation through wet etching or lift-off processes while simultaneously enabling fine pattern definition through controlled oxygen concentration and sheet resistance.
2Area of stationary object
If the distance between electrodes is reduced to achieve fine pitch segments, then the light emitting device occupies less space and is suitable for high-resolution displays, but conventional patterning methods cannot form such fine patterns
Solution Approach 1:
The patent modifies the sheet resistance parameter of the contact electrode film by controlling oxygen concentration during formation. This parameter change enables the film to support fine pattern formation through conventional wet etching or lift-off processes, allowing electrode distances to be reduced to achieve fine pitch segments suitable for high-resolution displays.
Solution Approach 2:
The contact electrode film acts as an intermediary layer between the p-type semiconductor layer and the bonding electrodes. By optimizing its properties (ITO or IZO material selection, oxygen concentration control, sheet resistance adjustment), this intermediary enables fine pattern transfer from photomask to electrode structure while maintaining compatibility with simple wet etching or lift-off processing methods.
3Ease of manufacture
If the contact electrode film has uniform sheet resistance, then the manufacturing process is simpler, but current diffusion cannot be controlled in the in-plane direction
Solution Approach 1:
The patent applies local quality by creating non-uniform oxygen concentration distribution within the contact electrode film thickness. The oxygen concentration is controlled to be higher in specific regions, which creates corresponding sheet resistance variations. This allows current diffusion to be controlled in the in-plane direction while maintaining a relatively simple single-step formation process through atmospheric pressure CVD or sputtering.
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 design enables the creation of light emitting devices with fine pitches suitable for high-resolution displays by effectively controlling current diffusion and preventing over-etching, thereby enhancing the density and efficiency of light emitting areas.
Implementation Method 1
the contact electrode film and the p-type semiconductor layer are configured so as to control current diffusion in in-plane directions thereof
Implementation Method 2
processing without using dry etching such as wet etching and lift-off processing is used
Data Source
AI summary
A light emitting device includes plural light emitting elements arranged on a substrate in lines and individually emit light each other. The light emitting device includes a single continuous n-type semiconductor layer on the substrate shared by the plural light emitting elements, a single continuous light emitting layer on the n-type semiconductor layer shared by the plural light emitting elements, a single continuous p-type semiconductor layer on the light emitting layer shared by the plural light emitting elements, a single continuous contact electrode film on the p-type semiconductor layer shared by the plural light emitting elements, and plural p-side bonding electrodes on the contact electrode film respectively used for the plural light emitting elements. The contact electrode film and the p-type semiconductor layer are configured so as to control current diffusion in in-plane directions thereof.