3D Measurement Apparatus Height Adjustment for PCB Solder Warpage
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Solution Overview
Problem
Conventional three-dimensional measurement apparatuses face challenges in maintaining measurement accuracy due to warpage and varying heights of solder pastes on printed circuit boards, leading to out-of-focus image data and decreased accuracy, especially with increased pixel density in imaging elements and diverse solder heights for different circuits.
Innovation Solution
A three-dimensional measurement apparatus and method that includes a measurement module with a first irradiation unit for height measurement, a second irradiation unit for three-dimensional measurement, and an imaging unit, which adjusts its height to ensure all measurement targets are within the appropriate focusing range by determining reference surface heights and required focusing ranges, allowing for precise positioning and accurate three-dimensional measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the imaging device uses a narrow field of vision with a small number of pixels, then the height adjustment can be completed only once, but the inspection area is limited and warpage affects measurement accuracy
Solution Approach 1:
The patent divides the inspection area into multiple sub-areas that can be imaged simultaneously by a single imaging device. By segmenting the overall measurement space into several overlapping fields of vision, the system can cover a larger inspection area while maintaining focus on all regions through coordinated height adjustment of multiple imaging devices.
2Area of stationary object
If the imaging device increases pixel density to widen the imaging area, then more solder pastes can be measured simultaneously, but warpage and height variations cause out-of-focus image data
Solution Approach 1:
The patent employs multiple imaging devices that can independently adjust their heights dynamically. Each imaging device focuses on a specific sub-area, and their heights are adjusted in coordination to ensure all measurement targets across the entire inspection area are within the depth of field, maintaining measurement precision while expanding the total imaging area.
Solution Approach 2:
The patent transitions from a single-plane measurement approach to a multi-height-plane measurement system. By introducing vertical dimension adjustments for multiple imaging devices, the system can capture solder pastes at different heights simultaneously, overcoming the depth of field limitation while maintaining focus accuracy across varied terrain including warpage and different solder paste heights.
3Measurement precision
If multiple height adjustments are performed to accommodate varying solder paste heights, then measurement accuracy improves, but measurement time increases
Solution Approach 1:
The patent performs preliminary height adjustment of multiple imaging devices before actual measurement begins. By pre-positioning each imaging device at the appropriate height for its designated sub-area, the system eliminates the need for repeated height adjustments during measurement, thereby maintaining high measurement accuracy while significantly reducing total measurement time.
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 configuration ensures that all solder pastes within a target measurement area are imaged in focus, improving measurement accuracy and reducing the number of height adjustments, thereby shortening measurement time and enhancing inspection quality.
Implementation Method 1
a first irradiation unit (13) configured to irradiate the target measurement area with slit light for height measurement
Implementation Method 2
a second irradiation unit (14) configured to project patterned light having a light intensity distribution in a fringe shape; The three-dimensional measurement apparatus having the configuration described above shifts the phase of the fringe pattern
Implementation Method 3
an imaging device configured to take an image of the inspection range with the fringe pattern projected thereon
Data Source
AI summary
A three-dimensional measurement apparatus measures measurement targets placed in a target measurement area on a measurement object. The apparatus includes: a measurement module that: is positioned with respect to the target measurement area, and includes: a first irradiator that irradiates the target measurement area with predetermined light for height measurement; a second irradiator that irradiates the target measurement area with predetermined patterned light for three-dimensional measurement; and an imaging device that takes an image of the target measurement area; and a control device that moves the measurement module in a height direction and successively positions the measurement module at a predetermined height position determined by mapping, and performs, based on image data taken by irradiating the target measurement area with predetermined patterned light, three-dimensional measurement to the measurement targets at the predetermined height position.