Organic EL Panel Control Device for Color Temperature Stability
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Solution Overview
Problem
Continuous lighting or long-time use of organic EL lighting devices leads to changes in luminance intensity ratios among colors, causing a shift in color temperature of the white light produced, which deteriorates the initial performance of the device.
Innovation Solution
An organic EL panel control device with a luminance control unit that adjusts the luminances of organic EL elements, excluding the one with the shortest luminance life, to maintain the initial color temperature of the white light produced by additive color mixing, using luminance detection units and a control unit to determine and adjust the driving currents or voltages based on measured luminance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If continuous lighting or long-time use of organic EL lighting device is performed, then the organic EL elements can provide sustained illumination, but the luminance intensity ratio among colors changes causing color temperature shift
Solution Approach 1:
The control device measures the luminance of each organic EL element and adjusts the drive currents dynamically based on measured values. This feedback mechanism compensates for luminance degradation and maintains consistent color temperature during continuous operation
Solution Approach 2:
The system changes the drive current parameters for each organic EL element individually based on their different luminance lifetimes. By adjusting current magnitude and timing, the system compensates for differential aging effects and maintains stable color output
2Illumination intensity
If the luminance of organic EL elements is increased to improve illumination, then the luminance life of elements especially those with shortest luminance life decreases
Solution Approach 1:
The system applies different drive conditions to different organic EL elements based on their individual characteristics, particularly their luminance lifetime. Elements with shorter luminance life receive adjusted drive currents compared to those with longer life, optimizing both illumination and longevity
Solution Approach 2:
The drive currents for each organic EL element are dynamically adjusted based on real-time luminance measurements and lifetime characteristics. This dynamic control allows the system to maintain optimal illumination while extending the operational life of elements with shorter luminance life
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 inhibits color temperature shifts and extends the life of the organic EL panel by maintaining consistent white light production and reducing the load on the organic EL element with the shortest luminance life.
Implementation Method 1
organic electroluminescence (EL) elements that produce white light (white organic EL elements) by additive color mixture of colors of light emitted from, e.g., red, green, and blue (RGB) light emitting materials
Data Source
AI summary
The present invention aims to provide an organic EL panel control device, a light source device, and an organic EL panel control method, capable of inhibiting the change (shift) in color temperature of white light produced by an organic EL panel to be controlled. The organic EL panel control device according to the present invention includes a luminance control unit. The luminance control unit controls, among a plurality of organic EL elements with different emission colors in an organic EL panel to be controlled, luminances of organic EL elements other than a reference organic EL element having a shortest luminance life in such a manner that, with reference to a luminance of the reference organic EL element, white light produced by additive color mixture of different colors of light emitted from the plurality of organic EL elements has the same color temperature as a previously set color temperature.