Edge Inspection System for Optical Devices
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Solution Overview
Problem
Detecting defects in optical devices such as waveguide combiners and metasurfaces is challenging due to their sub-wavelength dimensions and complex structures, making efficient inspection difficult and time-consuming, especially when integrated into manufacturing processes.
Innovation Solution
An inspection system comprising a stage with an interior and exterior support, a cover, and a light source with a focusing lens that directs light through a slit to illuminate optical devices on a substrate, allowing for high-contrast imaging and defect detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional inspection methods are used to detect defects on optical devices, then defect detection may be achieved, but the inspection process becomes time-consuming and inefficient
Solution Approach 1:
The patent transitions from conventional top-down inspection to edge illumination inspection, changing the dimensional approach by directing light from the side edges of the substrate. This allows light to penetrate through the thickness of the substrate and illuminate structures from a different spatial dimension, enabling efficient inspection of sub-wavelength features without time-consuming conventional methods
2Illumination intensity
If light is directed to illuminate structures on optical devices, then visibility of sub-wavelength structures improves, but efficient and high-contrast illumination is difficult to achieve
Solution Approach 1:
The illumination system is segmented into distinct functional components: a light source positioned at the edge, a focusing lens for precise light concentration, and a defined illumination region. This segmentation allows each component to be optimized independently, achieving high-contrast illumination of sub-wavelength structures without requiring a complex integrated system
Solution Approach 2:
The patent introduces an intermediary focusing lens that mediates between the light source and the substrate edge. This intermediary component concentrates and directs light efficiently onto the substrate edge, achieving high illumination intensity and contrast while keeping the overall system design manageable and not overly complex
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 system enables efficient and high-throughput inspection of optical devices by illuminating structures on the substrate, improving visibility and allowing for the detection of defects like fall-on particles, missing patterns, or film non-uniformity, thereby enhancing manufacturing quality control.
Implementation Method 1
a focusing lens operable to focus the light to the slit
Implementation Method 2
Generated light is propagated through the optical device until the light exits the optical device
Data Source
AI summary
Embodiments described herein relate to an inspection system for illumination of optical devices. The inspection system includes a stage, a focusing lens, a light source, a reflective surface, and a camera. The inspection system is operable to provide a light to a substrate. The substrate is positioned on the inspection system such that an edge of the substrate is exposed. The inspection system focuses light to the edge such that the light propagates through the substrate. The light is coupled out of the substrate, illuminating one or more optical devices disposed on the substrate. The illumination allows the camera to capture images to be inspected. The images are inspected to detect defects of the substrate.