Organic EL Illumination Device with Individualized Drive Signal Control
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Solution Overview
Problem
Existing illumination devices using organic EL elements face variations in luminance and chromaticity due to discrepancies in film thickness and electrical characteristics, which worsen over time, leading to inconsistent light output and color quality.
Innovation Solution
An illumination device with a control system that receives chromaticity and luminance information for each organic EL element, time-divides the drive signal into specific intervals, and adjusts the signal amplitude and supply time to match individual characteristics, ensuring consistent light output and color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single drive signal is supplied to all organic EL elements, then the device structure is simple, but variations in luminance and chromaticity occur due to discrepancies in film thickness and electrical characteristics
Solution Approach 1:
The patent divides the unit time interval into multiple specific intervals and supplies different drive signals to different organic EL elements within each interval. This segmentation approach allows individualized control of each element's drive conditions, compensating for manufacturing variations in film thickness and electrical characteristics while maintaining overall system manageability.
2Productivity
If the emission time interval is extended to increase light output, then the illumination effectiveness is improved, but deterioration of luminance and chromaticity characteristics worsens
Solution Approach 1:
The patent implements periodic drive signals with specific duty ratios within divided time intervals. By controlling the on/off timing and duration of drive signals periodically, the system can extend effective emission time while providing rest periods that reduce cumulative deterioration, thus maintaining luminance and chromaticity stability over extended operation.
Solution Approach 2:
The patent dynamically adjusts the drive signal characteristics (amplitude, duration, timing) for each organic EL element based on its individual characteristics. This dynamic control allows the system to optimize emission time for each element, extending overall illumination effectiveness while adapting to individual deterioration rates to maintain reliability.
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 approach effectively suppresses variations in luminance and chromaticity among organic EL elements, maintaining consistent light quality even as the elements deteriorate over time, reducing the need for frequent replacements and lowering operational costs.
Implementation Method 1
An organic EL (ElectroLuminescent) element is one light-emitting element used in illumination devices
Data Source
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AI summary
The present invention has the object of suppressing variations of luminance and chromaticity among a plurality of organic EL elements. An illumination device includes: a plurality of organic EL elements; an operation unit that receives, for each organic EL element, chromaticity information that indicates chromaticity of the relevant organic EL element and luminance information that indicates the luminance of the relevant organic EL element; and a supply unit that, for each of the organic EL elements, supplies to an organic EL element a drive signal having amplitude that accords with the chromaticity indicated by the chromaticity information for that organic EL element for, within a unit time interval, a time interval that accords with luminance indicated by the luminance information for that organic EL element.