Segmented LED Array Color Error Correction
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Solution Overview
Problem
Conventional LED arrays experience undesirable color errors due to over-conversion of light and leaked light, resulting in color variations and shading in photographed scenes, particularly in segmented LED arrays with phosphor layers.
Innovation Solution
The LED array system selectively illuminates neighboring segments around a primary illuminated segment to a low intensity, typically less than 10% of the primary segment's illumination, to correct color errors, with the illumination level calibrated based on physical characteristics such as die structure and layer thickness, thereby minimizing contrast impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single LED segment is illuminated in a segmented LED array, then flash intensity and contrast are improved, but color errors and yellow rim effects appear in adjacent switched-off segments
Solution Approach 1:
The patent applies preliminary anti-action by pre-illuminating adjacent LED segments at a reduced intensity (e.g., 10-50% of the primary segment) before or during the main flash. This compensates for the light leakage and over-conversion effects that would otherwise cause yellow rim effects and color errors in the switched-off segments, thereby preventing the harmful color distortion before it occurs.
Solution Approach 2:
The patent implements local quality by applying different illumination intensities to different spatial zones of the LED array. The primary illuminated segment operates at full intensity while adjacent segments operate at reduced intensity, creating a spatially varying illumination profile that maintains contrast in the primary zone while reducing color errors in adjacent zones.
2Object-affected harmful factors
If neighboring LED segments are illuminated to correct color errors, then color accuracy is improved, but contrast between LED segments may be diminished
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the illumination intensity parameter of adjacent LED segments to an optimized range (10-50% of the primary segment). This parameter optimization balances two competing requirements: providing enough illumination to reduce color errors while maintaining sufficient intensity differential to preserve contrast and avoid overexposure in the adjacent segments.
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 reduces color errors and maintains contrast by adjusting the luminance of adjacent LED segments, optimizing color accuracy and reducing halo effects in photographed scenes.
Implementation Method 1
In one embodiment, a segmented light emitting diode (LED) array includes a plurality of LED segments, wherein each LED segment can be selectively controlled to illuminate a correlated part of a scene
Implementation Method 2
for white LEDs, color variations still exist due to local over-conversion of light. This over-conversion can produce yellow light due to locally thicker phosphor layers in the LED array
Implementation Method 3
In monolithic matrix LED arrays, a sapphire or phosphor layer covers the active light emission sites as a single piece or layer. This arrangement leads to light deflecting inside the matrix blocks
Data Source
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AI summary
A method of color error correction for a segmented LED array is disclosed. The method includes calculating a target luminance for LED segments in a segmented LED array based on an initial luminance pattern, determining a luminance ratio based on the target luminance, the luminance ratio defined as a ratio of a primary luminance value of the primary LED segment to a secondary luminance value of the at least one adjacent LED segment, and comparing the luminance ratio to a predefined threshold ratio. If the luminance ratio is greater than or equal to the predefined ratio, then the secondary luminance value of the at least one adjacent LED segment is maintained. If the luminance ratio is less than the predefined ratio, then the secondary luminance value of the at least one adjacent LED segment is increased.