Alternating Current Drive for Combined-Light Source Lifetime
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Solution Overview
Problem
The life of laser diodes and LEDs is inversely proportional to current value and junction temperature, leading to decreased light intensity when current is lowered to extend life, resulting in increased device size and cost when more elements are needed, and existing methods complicate the process of optimizing light conversion efficiency.
Innovation Solution
A light source driving device that alternately supplies different current values to multiple light emitting element groups, combining their outputs to achieve a higher light intensity than with a single rated current, thereby extending the life of the elements while maintaining a desired output without increasing device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the current value is lowered to extend the life of light emitting elements, then the life is improved, but the light intensity decreases
Solution Approach 1:
The patent applies periodic action by alternately switching between two different current values (first current and second current) to drive different groups of light emitting elements. This periodic switching allows the system to achieve high average light intensity while each group operates at lower current values for extended periods, thereby extending element life while maintaining brightness.
Solution Approach 2:
The patent segments the light emitting elements into multiple groups (first light emitting element group and second light emitting element group), where each group is driven by different current values at different time periods. This segmentation enables independent control of each group's operating conditions, allowing optimization of both life and light intensity.
2Illumination intensity
If the number of laser diodes and LEDs is increased to obtain required light output, then the light intensity is improved, but the device size increases
Solution Approach 1:
By using periodic action with alternating current supply to different groups, the patent achieves high average light output without requiring all elements to operate at full current simultaneously. This reduces the total number of elements needed compared to continuous full-power operation, thereby reducing device size.
Solution Approach 2:
The patent employs dynamic current allocation where the current values supplied to different groups change over time. This dynamic approach allows efficient utilization of fewer light emitting elements through temporal multiplexing, reducing the spatial footprint compared to static full-power designs.
3Duration of action of stationary object
If the cooling capacity is increased to lower junction temperature, then the life is improved, but the cost and device size increase
Solution Approach 1:
The periodic switching between different current values reduces the average power dissipation and junction temperature compared to continuous full-power operation. This reduces the cooling capacity required to maintain acceptable operating temperatures, thereby reducing cooling system size and cost while still extending element life.
Solution Approach 2:
The patent changes the operating parameters (current values) of the light emitting elements to operate at lower average currents, which directly reduces heat generation. This parameter change approach reduces the thermal management burden without requiring complex cooling systems.
4Productivity
If driving currents are allocated to maximize light conversion efficiency, then the efficiency is improved, but the process complexity increases
Solution Approach 1:
The patent uses a relatively simple periodic switching control scheme between two current values rather than complex continuous optimization algorithms. This periodic approach achieves good light conversion efficiency through temporal multiplexing while keeping the control process simpler and more implementable.
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 method improves the life of light emitting elements by alternately switching current values, ensuring a desired light output is achieved with fewer elements, reducing the need for larger devices and lowering costs.
Implementation Method 1
a light source driving device for driving a plurality of light emitting element groups in a light source device that outputs combined light obtained by combining light emitted from the light emitting element groups
Implementation Method 2
a light combining lens that outputs combined light by combining light emitted from the plurality of light emitting element groups
Data Source
AI summary
Disclosed is a light source driving device (20) for driving a plurality of light emitting element groups in a light source device that outputs combined light obtained by combining light emitted from the light emitting element groups, the light source driving device including a control circuit (201) that supplies a current that alternately repeats a first period in which a first current is supplied and a second period in which a second current having a current value different from a current value of the first current is supplied to the plurality of light emitting element groups, the second current being supplied to a second light emitting element group in a case where the first current is being supplied to a first light emitting element group, and the first current being supplied to the second light emitting element group in a case where the second current is being supplied to the first light emitting element group, wherein a target value of a light intensity obtained by the combined light is a light intensity that is higher than a light intensity obtained in a case where a current having a rated value is applied to any one of the light emitting element groups, and wherein a total of the current value of the first current and the current value of the second current is greater than the rated value.