Light-Emitting Element Electrode Layout for Uniform Current Spreading
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Solution Overview
Problem
Existing light-emitting elements experience unevenness in current density distribution, leading to inconsistencies in emission intensity, which can cause thermal alterations and reduced luminance.
Innovation Solution
A light-emitting element design featuring a semiconductor structure with a light-transmissive conductive film and insulating film configuration, including specific electrode layers and openings, that diffuses current and reduces concentration at high emission intensity regions, thereby minimizing unevenness in current density and emission intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrode configurations are used, then manufacturing is simpler, but current density distribution becomes uneven
Solution Approach 1:
The light-transmissive conductive film is divided into multiple regions with different transparency characteristics. The film includes a first region with higher light transparency and a second region with lower light transparency, creating segmented functional zones that control current distribution while maintaining optical performance.
Solution Approach 2:
Different regions of the light-transmissive conductive film are assigned different optical and electrical properties. The first region has higher light transparency for light extraction, while the second region has lower light transparency and higher sheet resistance for current diffusion, creating local quality variations that solve the uniformity problem.
2Productivity
If current is concentrated in high emission intensity regions, then luminance increases, but thermal damage occurs
Solution Approach 1:
The light-transmissive conductive film acts as an intermediary between the electrode and the active layer. It diffuses current through its resistance while allowing light to pass through, preventing direct current concentration at the electrode-active layer interface and reducing thermal damage risk.
Solution Approach 2:
The sheet resistance of the light-transmissive conductive film is specifically controlled within a predetermined range (e.g., 10-1000 Ω/□) to optimize the balance between current diffusion capability and light transparency. This parameter control ensures sufficient current spreading without excessive voltage drop.
3Illumination intensity
If light transparency of conductive film is increased, then light extraction improves, but current diffusion capability decreases
Solution Approach 1:
The conductive film is segmented into regions with different transparency levels. The first region has higher transparency for light extraction, while the second region has lower transparency and higher resistance for current diffusion, allowing both functions to coexist in different spatial zones.
Solution Approach 2:
The problem is solved by adding a spatial dimension to the solution. Instead of making the entire film uniformly transparent or resistant, the film's properties vary across its surface area, creating a two-dimensional property distribution that simultaneously achieves light extraction and current diffusion.
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 effectively reduces unevenness in current density and emission intensity distribution, enhancing light extraction and luminance while preventing thermal damage.
Implementation Method 1
a light-reflective conductive film disposed above the light-transmissive insulating film and being in contact with the light-transmissive conductive film in the first opening
Implementation Method 2
a light-transmissive conductive film disposed above the second semiconductor layer
Data Source
AI summary
A light-emitting element includes a semiconductor structure body, a light-transmissive conductive film, a light-transmissive insulating film provided with a plurality of first openings, and a light-reflective conductive film contacting the light-transmissive conductive film in the first openings. In a top view, the extending portions of a first semiconductor layer include end portions (the portion of the extending portion located closest to a side of a second outer peripheral portion), the light-transmissive conductive film includes outer edges facing the end portions of the extending portions in a second direction, respectively, the first openings are not located between a first outer peripheral portion and a first straight line passing through an outer edge closest to the second outer peripheral portion among the plurality of outer edges of the light-transmissive conductive film and extending in a first direction, and are located between the first straight line and the second outer peripheral portion.