Silicon Wafer Edge Detection Optics for Low-Background Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing silicon wafer side edge detection methods using a square prism result in a too bright photographic background due to multiple reflections, interfering with the imaging effect.
Innovation Solution
A silicon wafer side edge detection device with first and second detection units, each comprising a point light source, reflective structure, and slit, which reflect and direct light to the wafer's edges for improved imaging, and optionally includes chamfer detection assemblies for comprehensive edge analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a square prism is used to reflect or transmit light from a light source, then the light can be directed to the silicon wafer, but the bottom of the square prism reflects light again resulting in a too bright photographic background that affects imaging effect
Solution Approach 1:
The patent extracts and removes the harmful reflective function from the bottom surface of the optical path defining element. By making the bottom surface non-reflective (using black matte paint or rough surface treatment), the unwanted secondary reflections that caused bright background are eliminated, while the primary light guidance function through the side surfaces remains intact.
Solution Approach 2:
The patent converts the harmful effect of light reflection from the bottom surface into a beneficial non-reflective surface. By intentionally designing the bottom surface to be non-reflective, the patent eliminates the interference with imaging while maintaining the optical path definition function, effectively turning a potential harmful reflection into a beneficial dark background for imaging.
2Device complexity
If a square prism is used for side edge detection, then the structure is simple, but the mounting and debugging process is complex due to optical path alignment requirements
Solution Approach 1:
The patent applies different surface properties to different parts of the optical path defining element: the side surfaces maintain high reflectivity or transparency for light guidance, while the bottom surface is treated to be non-reflective. This local differentiation simplifies the optical path design and makes mounting easier by eliminating the need to control bottom surface reflections.
3Reliability
If a square prism is used for light reflection, then the basic detection function is achieved, but the imaging effect is degraded due to multiple reflections
Solution Approach 1:
The patent segments the optical path defining element into functionally distinct surfaces: side surfaces for light guidance and reflection, and a bottom surface for light absorption. This segmentation allows each surface to perform its specific function optimally, with the bottom surface dedicated to preventing unwanted reflections that would degrade imaging quality.
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 device achieves improved imaging effects by reducing excessive illumination, facilitates mounting and debugging, and supports large-scale industrial use, while also detecting chamfers, enhancing overall detection accuracy and efficiency.
Implementation Method 1
the reflective structure is configured to reflect light emitted by the first point light source and reflect the light to a side edge of a silicon wafer to be detected
Data Source
AI summary
The present disclosure discloses a silicon wafer side edge detection device, comprising a first detection unit and a second detection unit, wherein the first detection unit and the second detection unit are of the same structure and are respectively configured to detect two mutually parallel side edges of a silicon wafer; and the first detection unit and the second detection unit each comprises a side edge detection assembly, the side edge detection assembly comprising a first point light source, a first optical path defining element, and a camera, wherein the first optical path defining element comprises a reflective structure and a slit, the reflective structure is configured to reflect light emitted by the first point light source and reflect the light to a side edge of a silicon wafer to be detected, and the light is reflected by the side edge of the silicon wafer.