Screen Printing Camera Offset Optical Axes
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Solution Overview
Problem
Traditional screen printing devices with a single camera have low imaging range, resolution, and recognition precision due to the coaxial imaging light directions, which cause disturbance and reduce the accuracy of board and screen mask alignment.
Innovation Solution
A screen printing device with an imaging part using a single camera, featuring offset upper and lower imaging optical axes, a half mirror, and a mirror to reflect light, along with separate illuminating parts for each axis, allowing precise imaging of board and mask recognition marks without disturbance from coaxial light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single camera with coaxial imaging optical axes is used to image both the board and screen mask, then the device construction is simplified, but the recognition precision is reduced due to disturbance light from mask openings
Solution Approach 1:
The patent transitions from coaxial imaging (same optical axis) to offset imaging (parallel but separated optical axes). By positioning the upper and lower imaging optical axes at different planar locations offset by a predetermined distance, the system eliminates disturbance light from mask openings while maintaining single-camera construction. This dimensional separation in the optical axis arrangement resolves the contradiction between construction simplicity and recognition precision.
2Device complexity
If the imaging field is divided into top and bottom halves to recognize screen mask and board, then a single camera can be used, but the imaging range and resolution are reduced
Solution Approach 1:
Instead of dividing the imaging field of a single camera into halves (which limits imaging range and resolution), the patent uses two separate imaging optical axes positioned at different heights and planar locations. This allows each optical axis to independently image its target (mask or board) with full resolution and appropriate imaging range, while still using a single camera body. The offset arrangement in three-dimensional space overcomes the limitations of field division.
3Adaptability or versatility
If imaging lights are incident from upwards and downwards coaxial directions, then both board and mask can be imaged with a single camera, but disturbance light from mask openings reduces recognition precision
Solution Approach 1:
The patent maintains the ability to image both board and mask from opposite directions (upwards and downwards) but eliminates the coaxial arrangement. By offsetting the upper and lower imaging optical axes in the planar direction by a predetermined distance, the system preserves dual imaging capability while preventing disturbance light from mask openings from entering the camera during board imaging. The non-coaxial offset arrangement resolves the precision problem while maintaining versatility.
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 solution enhances recognition precision by minimizing disturbance light and maintaining high resolution, enabling accurate alignment of the screen mask and board using a simple camera construction.
Implementation Method 1
a half mirror having a semi-reflective surface disposed to obliquely face downwards and towards the camera, and horizontally reflecting an imaging light, which is incident through the lower imaging optical axis, to be incident on the camera through the incidence optical axis
Implementation Method 2
a mirror which has a full reflective surface that is disposed to obliquely face downwards and towards the camera, which is disposed at a position further than the half mirror from the camera, and which horizontally reflects an imaging light which is incident through the upper imaging optical axis to pass through the half mirror and then be incident on the camera through the incidence optical axis
Data Source
AI summary
An imaging part in a screen printing device which images a board and a screen mask includes a single camera which is disposed with a posture of horizontally facing towards an incidence optical axis, a half mirror which makes an imaging light, which is incident through a lower imaging optical axis, to be incident on a camera, and a mirror which makes an imaging light, which is incident through an upper imaging optical axis, to pass through the half mirror and to be incident on the camera, and further has an upper illuminating part and a lower illuminating part which individually illuminate respective imaging objects. Imaging light is taken in the camera in a state that the upper illuminating part and the lower illuminating part are individually operated in a mask imaging step and a board imaging step, respectively.