Surface-Emitting Laser Electrode Layout for Transparent Film Reliability
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Solution Overview
Problem
The reliability of transparent conductive films in surface emitting lasers is compromised due to variations in characteristics when subjected to current input over time, leading to issues like voltage rise, open failures, and current leakage.
Innovation Solution
The transparent conductive film is designed with a greater thickness at the position in contact with the pad electrode compared to the optical path, and can be formed in a tapered or staircase shape, with varying film qualities and materials to manage current distribution and optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transparent conductive film is made thicker to improve current conduction and reliability, then the reliability improves, but light absorption increases and optical performance deteriorates
Solution Approach 1:
The patent applies local quality by creating a transparent conductive film with spatially varying thickness: the film is thicker in the current injection region (contact area with pad electrode) to improve current conduction and reliability, and thinner in the light emission region (optical path area) to reduce light absorption and maintain optical performance. This non-uniform thickness distribution allows each region to have the appropriate film thickness for its specific function.
2Ease of manufacture
If the transparent conductive film has uniform thickness, then manufacturing is simple, but current distribution becomes uneven leading to reliability issues
Solution Approach 1:
The patent implements local quality by designing the transparent conductive film with different thicknesses in different regions: a thicker portion in the current injection region to ensure reliable current conduction and prevent characteristic variations, and a thinner portion in the light emission region. This resolves the contradiction by making the film thickness adapt to the local functional requirements rather than using a uniform thickness throughout.
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 design enhances the reliability of the transparent conductive film by suppressing variations in characteristics, reducing light absorption, and improving the overall performance of the surface emitting laser.
Implementation Method 1
a transparent conductive film (32), a pad electrode (33), and a second multilayer reflective mirror (42)
Implementation Method 2
a first multilayer reflective mirror (41); an active layer (23); and a second structure including a transparent conductive film (32), a pad electrode (33), and a second multilayer reflective mirror (42)
Implementation Method 3
an active layer (23)
Data Source
AI summary
To provide a surface emitting laser, a surface emitting laser array, and an electronic device that improve the reliability of a transparent conductive film.The present technique provides a surface emitting laser including: a first structure including a first multilayer reflective mirror; an active layer; and a second structure including a transparent conductive film, a pad electrode, and a second multilayer reflective mirror, the first structure, the active layer, and the second structure being disposed in this order, in which a film thickness of the transparent conductive film disposed at a position in contact with the pad electrode is greater than a film thickness of the transparent conductive film disposed on an optical path of light generated by the active layer.