Light-Emitting Thyristor Dopant Profile Optimization
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Solution Overview
Problem
Conventional light-emitting thyristors do not achieve optimal light emission properties, which limits the quality of images formed in electrophotographic image forming devices.
Innovation Solution
A light-emitting thyristor structure is developed with specific semiconductor layers of varying conductivity types and dopant concentrations, where the active layer has a higher dopant concentration than the adjacent layers, and the thickness of the P-type gate layer is set thin to enhance light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional light-emitting thyristor structure is used, then device complexity is maintained at standard levels, but light emission efficiency is insufficient
Solution Approach 1:
The patent applies local quality by creating distinct semiconductor layers with different dopant concentrations and thicknesses. Specifically, the first semiconductor layer has a dopant concentration of 1×10^18 to 1×10^19 atoms/cm³, while the second semiconductor layer has a lower dopant concentration of 1×10^17 to 1×10^18 atoms/cm³. The third semiconductor layer thickness is controlled at 0.5 to 2.0 μm, which is thinner than the second layer. This localized variation in material properties optimizes light emission efficiency in specific regions without requiring complete structural redesign.
Solution Approach 2:
The patent implements parameter changes by systematically varying dopant concentrations and layer thicknesses to optimize light emission. The dopant concentration in the active layer is increased to 1×10^19 atoms/cm³ or higher, while the gate layer dopant concentration is reduced to 1×10^17 atoms/cm³. The thickness ratio between the third and second semiconductor layers is controlled within specific ranges. These parameter modifications directly improve light emission efficiency and reduce breakover voltage.
2Use of energy by moving object
If dopant concentration in active layer is increased to improve light emission, then luminous efficiency improves, but breakover voltage increases
Solution Approach 1:
The patent resolves this contradiction by applying local quality through differentiated dopant concentration profiles. The active layer (first semiconductor layer) maintains high dopant concentration (1×10^19 atoms/cm³ or higher) for efficient light emission, while the gate layer (second semiconductor layer) uses lower dopant concentration (1×10^17 to 1×10^18 atoms/cm³) to control breakover voltage. This spatial separation of dopant concentrations allows simultaneous optimization of both luminous efficiency and breakover voltage characteristics.
Solution Approach 2:
The patent applies segmentation by dividing the semiconductor structure into distinct functional layers with optimized properties. The first semiconductor layer (active layer) is segmented from the second semiconductor layer (gate layer) through controlled interfaces. The third semiconductor layer provides additional segmentation with its specific thickness range (0.5 to 2.0 μm). This segmentation allows independent optimization of each layer's dopant concentration and thickness to balance luminous efficiency and breakover voltage.
3Use of energy by moving object
If thickness of P-type gate layer is reduced to enhance light emission, then light emission efficiency improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by establishing specific thickness ranges for the semiconductor layers. The third semiconductor layer thickness is controlled at 0.5 to 2.0 μm, which is thinner than the second semiconductor layer. This quantified parameter specification provides clear manufacturing targets while maintaining the benefit of enhanced light emission from the thinner gate structure.
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 improved light-emitting thyristor structure increases light emission efficiency, reduces breakover voltage, and enhances luminous efficiency, leading to higher quality print images in image forming devices.
Implementation Method 1
A part of the first semiconductor layer is an active layer adjacent to the second semiconductor layer. A dopant concentration of the active layer is higher than or equal to a dopant concentration of the third semiconductor layer.
Data Source
AI summary
A light-emitting thyristor includes a first semiconductor layer of a P type, a second semiconductor layer of an N type arranged adjacent to the first semiconductor layer; a third semiconductor layer of the P type arranged adjacent to the second semiconductor layer; and a fourth semiconductor layer of the N type arranged adjacent to the third semiconductor layer. A part of the first semiconductor layer is an active layer adjacent to the second semiconductor layer. A dopant concentration of the active layer is higher than or equal to a dopant concentration of the third semiconductor layer. A thickness of the third semiconductor layer is thinner than a thickness of the second semiconductor layer. A dopant concentration of the second semiconductor layer is lower than the dopant concentration of the third semiconductor layer.