Semiconductor Light-Emitting Device Current Control
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Solution Overview
Problem
Semiconductor laser devices face issues with current crowding and heat generation due to forward voltage differences among serially connected laser diodes, leading to reduced service life and variable output.
Innovation Solution
A semiconductor light-emitting device with a light-emitting element group connected in columns, current control elements, a forward voltage monitoring circuit, and a control circuit that adjusts current control elements to maintain total forward voltage variations within a threshold, ensuring balanced current distribution and reduced heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a plurality of serially connected laser diodes are connected in parallel columns with one current control element, then the device configuration is simplified, but current concentrates in specific parallel lines due to forward voltage differences, reducing service life
Solution Approach 1:
The invention divides the single current control function into multiple segmentated current control elements, with each element controlling a specific column of parallel-connected laser diodes. This segmentation allows independent adjustment of current in each column, preventing current concentration and extending service life while maintaining relatively simple overall configuration.
Solution Approach 2:
The invention applies local quality by providing individual current control elements for each column of parallel laser diodes, enabling localized current adjustment based on the specific forward voltage characteristics of each column. This local control approach balances current distribution across columns with different forward voltage levels.
2Reliability
If the number of laser diodes is changed in each line to absorb forward voltage differences, then current distribution is improved, but the total output of laser diodes changes
Solution Approach 1:
The invention changes the electrical parameter (current) rather than the structural parameter (number of laser diodes). By adjusting the current through each column using individual current control elements based on monitored forward voltage levels, the system achieves balanced current distribution while maintaining a constant total number of laser diodes and their configured light output.
3Reliability
If current control elements are connected to control each column of parallel laser diodes, then current distribution is improved, but heat generation of current control elements increases due to forward voltage differences
Solution Approach 1:
The invention implements feedback control by monitoring the forward voltage of each column of laser diodes and using this information to adjust the current through corresponding current control elements. This feedback mechanism optimizes current distribution to minimize power loss and heat generation in the current control elements while maintaining balanced operation across all columns.
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 solution achieves desirable light output, extends the service life of light-emitting elements, and improves heat management by balancing current distribution and reducing heat generation in current control elements.
Implementation Method 1
a forward voltage monitoring circuit for monitoring, for each of the columns, the total forward voltage across the light-emitting elements
Implementation Method 2
a control circuit for controlling the current control elements, on the basis of the total forward voltage across the light-emitting elements from each of the columns detected by the forward voltage monitoring circuit
Implementation Method 3
a light-emitting element group configured from a plurality of columns of serially connected light-emitting elements
Data Source
AI summary
The present invention comprises: a light-emitting element group configured from columns of serially connected light-emitting elements, one of the ends from each of the columns of the light-emitting elements being collectively connected to a power source; current control elements, provided to correspond to the columns, and being connected to each of the columns of the light-emitting elements at the other end thereof, for controlling the current flowing through the light-emitting elements; a forward voltage monitoring circuit for monitoring, for each of the columns, the total forward voltage across the light-emitting elements; and a control circuit for controlling the current control elements, on the basis of the total forward voltage across the light-emitting elements from each of the columns detected by the forward voltage monitoring circuit, in such a manner that the variations in the total forward voltage across the columns of the light-emitting elements reach a threshold value or lower.