Optical Component Inspection Using Acute-Angle Illumination
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Solution Overview
Problem
Existing component inspection technologies struggle to detect defects such as unevenness and layer detachments on semiconductor components due to limited image sharpness and shallow depth of field, leading to incorrect classification and reduced product quality.
Innovation Solution
A device and method for optical inspection using a light source that emits light at an acute angle to the optical axis of an imaging sensor, allowing detection of defects on side surfaces and end faces of components by analyzing the distribution of emerging light intensity, with adjustable light deflection and focusing devices to enhance image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging sensors are used to inspect component surfaces, then the inspection system is simple and fast, but the image sharpness is insufficient and depth of field is shallow, leading to missed defects
Solution Approach 1:
The patent transitions from conventional direct imaging to optical sectioning in the depth dimension. By introducing axial scanning and focal plane reconstruction, the system achieves three-dimensional optical sectioning capability, allowing sharp imaging of surfaces at different depths within the component while maintaining a relatively simple optical configuration.
Solution Approach 2:
The patent embeds multiple focal planes within a single optical path by implementing axial scanning. The imaging sensor captures multiple optical sections at different depths, which are then reconstructed to form a composite image with extended depth of field. This nesting of focal planes allows the system to maintain simplicity while achieving high measurement precision across multiple depth levels.
2Reliability
If multiple surfaces of components are inspected, then defect detection coverage is improved, but inspection time increases
Solution Approach 1:
The patent implements continuous axial scanning during the inspection process, allowing the optical sectioning to occur without interrupting the component transport. The imaging sensor continuously captures optical sections at different depths as the component moves through the inspection zone, enabling multi-surface inspection to occur in parallel with the conveyance process rather than as separate sequential steps.
Solution Approach 2:
The system pre-processes the optical data by reconstructing multiple focal planes and combining them into a single composite image with extended depth of field before defect analysis. This preliminary reconstruction prepares all necessary surface information in advance, allowing defect detection algorithms to operate on a complete multi-surface image without requiring additional inspection passes, thereby maintaining high throughput.
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 reliable detection of defects on component surfaces and internal layers, improving inspection accuracy and throughput while reducing the risk of defective components being processed further.
Implementation Method 1
A light source (170) is arranged and intended to emit light incident at a first acute angle to an optical axis (OA) of an imaging sensor (180)
Implementation Method 2
The imaging sensor (180) is arranged and intended to detect light emerging from the first of the end faces (S1) of the component (B) and to signal a distribution of the intensity of the emerging light
Data Source
AI summary
A device for optical inspection of a component located on a fixture. The fixture picks up the component at a delivery point, conveys it along a conveying path to a deposit point, and deposits it there. A light source delivers light at a first acute angle to the optical axis of an imaging sensor onto a first end face of the component when the component located at the holder is oriented with its end face at least normal to the optical axis of the imaging sensor. The latter inspects at least one side surface of the component and/or an area inside the component near a second of the end surfaces and near respective ones of the side surfaces. The imaging sensor detects light emerging from the first end face to signal a distribution of the intensity of the emerging light to an evaluation device.