Variable Brightness Interference Height Detection for Paste Film Saturation
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Solution Overview
Problem
The existing height detection methods face challenges in accurately detecting the height of a target object, particularly when the particle size of the material is small, leading to saturation issues with interference light intensity, making it difficult to determine the peak contrast value and hence the height of the object.
Innovation Solution
A height detection apparatus that adjusts the brightness of white light in multiple levels while moving the two-beam interference objective lens relative to the target object, capturing images of interference light and detecting the position of highest intensity for each pixel to accurately determine the object's height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the brightness of white light is increased to increase the intensity of interference light for the paste film, then the intensity of interference light for the paste film is improved, but the intensity of interference light for the metal film becomes saturated
Solution Approach 1:
The patent applies dynamics by making the illumination intensity variable rather than fixed. The light source brightness is dynamically adjusted based on the detection target properties - using higher brightness levels for paste films with large particle sizes that scatter light, and lower brightness levels for metal films with small particle sizes that produce strong regular reflection. This dynamic adaptation resolves the contradiction by preventing saturation while ensuring sufficient signal intensity for accurate height detection.
Solution Approach 2:
The patent changes the parameter of illumination intensity (brightness level) to resolve the technical contradiction. By adjusting this parameter according to the target object's optical properties, the system optimizes the interference light intensity for each specific measurement scenario, avoiding both insufficient signal and saturation conditions.
2Reliability
If the brightness of white light is increased to detect the paste film with large particle size, then the detectability of paste film is improved, but the metal film with small particle size becomes saturated
Solution Approach 1:
The patent applies local quality by tailoring the illumination intensity to the specific properties of each detection target. Different regions of the measurement space (paste film areas vs. metal film areas) receive differently optimized light intensities based on their respective optical characteristics, ensuring reliable detection without causing saturation in either case.
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 allows for precise detection of the object's height by setting the light brightness according to the object's properties, effectively overcoming the saturation issues and ensuring accurate measurements.
Implementation Method 1
cause interference between reflected light from the target object and reflected light from the reference surface to obtain interference light
Implementation Method 2
apply one of the two light beams to the target object and the other light beam to a reference surface, and cause interference between reflected light from the target object and reflected light from the reference surface
Data Source
AI summary
A height detection apparatus successively changes the brightness of white light from a first level to a second level in accordance with a position of a Z stage and captures an image of interference light while moving a two-beam interference objective lens relative to a paste film in an optical axis direction, detects, as a focus position, a position of the Z stage where the intensity of interference light is highest in a period during which the brightness of white light is set to the first or second level, for each pixel of the captured image, and obtains the height of the paste film based on a detection result.