Light-Emitting Element With Segmented Conductive Film
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Solution Overview
Problem
Current light-emitting elements face reduced light extraction efficiency due to absorption by metal electrodes and light-transmissive conductive films, despite efforts to improve this with insulating films and reflective layers.
Innovation Solution
A light-emitting element design featuring a semiconductor stacked body with an insulating film, a light-transmissive conductive film, and a reflective film, where the light-transmissive conductive film has openings that reduce its surface area under the p-side electrode, and the reflective film is positioned between the insulating film and the p-side electrode to enhance light reflection and extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a light-transmissive conductive film is provided to contact the upper portion of the metal electrode, then current diffusion to a wide area is achieved, but light extraction efficiency decreases due to absorption
Solution Approach 1:
The light-transmissive conductive film is segmented by forming openings (first openings and second openings) that divide the film into multiple regions. This segmentation reduces the total area of the conductive film that absorbs light, while still maintaining sufficient current diffusion paths through the remaining conductive regions. The openings create a pattern that balances electrical functionality with optical performance.
Solution Approach 2:
Different regions of the light-transmissive conductive film have different properties: regions with openings allow better light transmission, while regions without openings provide current diffusion. The film structure is locally optimized by strategically placing openings in areas where light extraction is prioritized, while maintaining continuous conductive paths in areas where current diffusion is needed.
2Loss of energy
If an insulating film is provided between the light-transmissive conductive film and the semiconductor layer, then light absorption by the metal electrode is reduced, but device complexity increases
Solution Approach 1:
The insulating film and reflective film are merged into a single integrated structure. The insulating film serves dual purposes: it provides electrical insulation between the metal electrode and the semiconductor layer, and it acts as a reflective layer that bounces light back into the semiconductor layer to enhance light extraction. This merging eliminates the need for separate insulating and reflective layers, reducing device complexity while maintaining the benefits of both functions.
3Loss of energy
If the surface area of the light-transmissive conductive film under the p-side electrode is reduced by providing openings, then light extraction efficiency increases, but current diffusion capability may be compromised
Solution Approach 1:
The openings are strategically positioned and sized to segment the conductive film in a way that maximizes light extraction while preserving current diffusion. The first openings and second openings are arranged to create sufficient conductive pathways for current to diffuse across the electrode region, while the openings themselves provide channels for improved light extraction. The segmentation pattern is optimized to balance these two competing requirements.
Solution Approach 2:
The openings are designed with asymmetric characteristics: the first openings have different dimensions than the second openings, and they are positioned at different locations relative to the p-side electrode. This asymmetric design allows optimization of light extraction in specific regions while maintaining current diffusion paths in other regions, achieving a balanced performance that symmetric designs cannot provide.
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 increases light extraction efficiency by minimizing optical absorption and maximizing reflection, leading to improved luminance distribution and light extraction from the light-emitting surface.
Implementation Method 1
a reflective film provided between the insulating film and the p-side electrode in the opening of the light-transmissive conductive film
Implementation Method 2
a light-transmissive conductive film provided on the p-type semiconductor layer and on the insulating film
Implementation Method 3
an insulating film such as SiO2 or the like having a lower refractive index than the light-transmissive conductive film is provided between the light-transmissive conductive film and the semiconductor layer
Data Source
AI summary
A light-emitting element includes: a semiconductor stacked body; an insulating film located on a p-type semiconductor layer; a p-side electrode located on the insulating film, the p-side electrode comprising a pad portion and an extension portion, the extension portion being continuous with the pad portion in a first direction; a light-transmissive conductive film located on the p-type semiconductor layer and on the insulating film, the light-transmissive conductive film having an opening that is continuous along the extension portion on the insulating film; and a reflective film located between the insulating film and the p-side electrode in the opening. The opening includes a first opening and a second opening. In the second direction, the light-transmissive conductive film is electrically connected to the extension portion of the p-side electrode at a portion adjacent to a region where the first opening is located.