Optoelectronic Module Dielectric Coating Defect Localization
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Solution Overview
Problem
Current methods for testing the integrity of dielectric coatings in optoelectronic modules are inadequate for online control, particularly when the conductive layer is continuous, and fail to locate or characterize faults in the dielectric coating, leading to defects discovered at late stages of manufacturing, resulting in additional costs.
Innovation Solution
A method involving electrical excitation of a support comprising a metal substrate, dielectric coating, and conductive layer, followed by photothermal examination using an infrared camera to detect and characterize defects in the dielectric coating, allowing for online fault detection and characterization without the presence of optoelectronic components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional leakage current testing methods are used on intermediate substrates with discrete pads, then electrical insulation can be tested, but online testing of continuous conductive layers is not possible and defect localization is impossible
Solution Approach 1:
The patent segments the continuous conductive layer into discrete testable zones by superimposing a grid pattern (e.g., 1mm x 1mm squares) over the entire substrate surface. This segmentation allows the continuous layer to be tested in multiple discrete locations simultaneously, enabling both online testing and defect localization without requiring physical pad structures.
Solution Approach 2:
The patent transitions from one-dimensional point-to-point leakage testing between discrete pads to two-dimensional surface-wide testing by applying voltage across the entire substrate surface and measuring current distribution across multiple grid points simultaneously. This dimensional expansion enables comprehensive coverage of continuous conductive layers and precise defect localization through spatial current mapping.
2Reliability
If high voltage breakdown testing is applied to the substrate, then dielectric integrity can be assessed, but defect localization and characterization are not possible
Solution Approach 1:
The patent implements feedback by measuring leakage current at each grid point and comparing it against reference values or thresholds. Areas exhibiting abnormal current characteristics provide feedback about potential defects, enabling localization and characterization of dielectric issues without requiring separate testing procedures.
Solution Approach 2:
The patent introduces a grid of measurement points as an intermediary between the voltage source and the dielectric layer. This intermediary structure enables detailed mapping of current distribution across the substrate surface, providing spatial information about dielectric defects while maintaining the high voltage breakdown testing function.
3Reliability
If optoelectronic devices are tested at late manufacturing stages, then device functionality can be verified, but defects in the substrate and layers are discovered too late, resulting in additional costs
Solution Approach 1:
The patent performs preliminary testing of the substrate and conductive layer integrity before completing the full optoelectronic device assembly. By testing the continuous conductive layer and dielectric coating at this intermediate stage using the grid-based leakage current method, defects are detected early in the manufacturing process, allowing for timely corrections and avoiding costly rework later.
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
Enables the localization and characterization of faults in the dielectric coating during the manufacturing process, reducing the likelihood of defects in the final optoelectronic module and minimizing additional costs associated with late-stage defect detection.
Implementation Method 1
a voltage is applied between the conductive layer and the metallic substrate. If at least one defect is present in the dielectric coating, at least a part of the conductive layer will exhibit a higher surface temperature at the level of the defects
Implementation Method 2
at least one image is taken of the excited support in the infrared domain
Data Source
Figure 1~3
AI summary
The invention relates to a method for the production of an optoelectronic module including a support (5) and an additional layer, said support being formed by an assembly (25) which has no optoelectronic properties and which comprises, successively, a metal substrate (27), a dielectric coating (29) disposed on the metal substrate, and an electrically conductive layer (31) disposed on the dielectric coating. The production method comprises: a step of providing the support and performing a method in which the support is checked, or providing the support after it has already been checked; and a step of depositing at least one additional layer on the electrically conductive layer. The checking method comprises the following steps: electrical excitation of the support by bringing the metal substrate and the electrically conductive layer into electrical contact with a voltage source (33); and photothermal examination of the excited support so as to detect any possible fault (49, 51) located at least partially in the dielectric coating (29) and to provide a photothermal examination result.