Semiconductor Light-Emitting Device with Directional Filter
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Solution Overview
Problem
Existing semiconductor light-emitting devices face challenges in achieving high photodetection accuracy due to the detection of spontaneous emission light by the photodetector, which interferes with the measurement of induced emission light output, leading to errors in light output level control.
Innovation Solution
A semiconductor light-emitting device is designed with a filter having a transmission characteristic that preferentially reflects spontaneous emission light, reducing its detection by the photodetector, thereby improving photodetection accuracy. The filter is arranged between the semiconductor light-emitting element and the photodetector, allowing induced emission light to pass through while reflecting most spontaneous emission light back to the emitter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a control layer is formed by oxidizing semiconductor material to block spontaneous emission light, then some blocking is achieved, but most spontaneous emission light still passes through without sufficient attenuation
Solution Approach 1:
The patent changes the optical parameters of the filter to achieve selective transmission. By designing the filter with specific transmission characteristics that differ for induced emission light and spontaneous emission light, the system can distinguish between these two types of light and block only the harmful spontaneous emission while transmitting the useful induced emission.
2Measurement precision
If a filter with directional transmission characteristic is used to reflect spontaneous emission light, then photodetection accuracy is improved, but the device structure becomes more complex
Solution Approach 1:
The filter and the photodetector are formed as a integrated unit structure, merging two separate components into one. This integration reduces the overall device complexity and the number of discrete parts while maintaining the selective filtering function that improves photodetection accuracy.
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 effectively reduces the detection level of spontaneous emission light, enhancing the photodetection accuracy by ensuring that only induced emission light is measured, thus improving the precision of light output level control.
Implementation Method 1
a filter having a transmission characteristic in which the transmittance in a direction parallel to the optical axis of induced emission light of light outputted from the semiconductor light-emitting element is higher than the transmittance in a direction different from the optical axis
Implementation Method 2
a semiconductor photodetector including a light-absorbing layer, the light-absorbing layer absorbing a part of the light passing through the filter
Data Source
AI summary
A semiconductor light-emitting device includes: a semiconductor light-emitting element including a first conductive type semiconductor layer, an active layer including a light-emitting region, and a second conductive type semiconductor layer in this order; a filter having a transmission characteristic in which the transmittance in a direction parallel to the optical axis of induced emission light of light outputted from the semiconductor light-emitting element is higher than the transmittance in a direction different from the optical axis; and a semiconductor photodetector including a light-absorbing layer, the light-absorbing layer absorbing a part of light passing through the filter, wherein the filter and the semiconductor photodetector are laminated in this order on the second conductive type semiconductor layer of the semiconductor light-emitting element, and are formed with the semiconductor light-emitting element as one unit.