Inkjet Head Alignment Using Laser Beam Imaging
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Solution Overview
Problem
Conventional liquid drop discharge apparatuses face challenges such as substrate damage from adhesive tapes, inefficient alignment processes, and reduced reliability due to the need for manual alignment and repeated ink discharge tests, which are time-consuming and prone to errors.
Innovation Solution
A liquid drop discharge apparatus equipped with a laser unit, camera, and position alignment unit that automatically aligns the inkjet head by emitting an aiming laser beam, capturing its position on the substrate, and calculating the necessary adjustments to ensure precise ink drop placement without the need for a separate glass test substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a glass for ink discharge test is attached to the substrate by adhesive tape, then ink discharge position alignment can be performed, but the substrate may be damaged and cannot be reused
Solution Approach 1:
The patent uses a test pattern printed on the substrate itself as a reference for alignment, rather than attaching a separate glass test substrate. The test pattern includes alignment marks and discharge position marks that are directly formed on the substrate, eliminating the need for adhesive tapes and external test glasses.
Solution Approach 2:
The patent removes the glass for ink discharge test from the system entirely. Instead of using an external test substrate, the alignment is performed using test patterns and marks directly on the substrate, combined with imaging device feedback, thereby eliminating the harmful adhesive tape attachment process.
2Loss of time
If fine position alignment is performed over only a small portion of the substrate, then alignment process time is reduced, but the reliability of discharge position alignment is lowered
Solution Approach 1:
The patent employs an imaging device to capture images of the test pattern and alignment marks on the substrate. The captured images are processed to calculate actual positions of pixels and discharge locations, providing feedback for automatic alignment adjustment. This ensures accurate alignment over the entire substrate area without requiring excessive manual intervention time.
Solution Approach 2:
The system performs automatic alignment using the imaging device and processing unit, which autonomously calculates position deviations and adjusts the inkjet head alignment based on test patterns printed on the substrate itself, eliminating the need for manual alignment operations over the entire substrate area.
3Reliability
If discharge position alignment is performed over the entire area of the substrate, then alignment reliability is improved, but the alignment process becomes time-consuming
Solution Approach 1:
The imaging device captures images of test patterns across the substrate, and the processing unit automatically analyzes these images to determine alignment accuracy over the entire substrate area. This automated feedback mechanism ensures comprehensive alignment reliability without requiring manual inspection of every region.
Solution Approach 2:
The system autonomously performs alignment verification and adjustment using the imaging device and processing unit, which automatically analyze test patterns across the entire substrate and make necessary adjustments without requiring repeated manual alignment operations, thereby maintaining high reliability while improving efficiency.
4Measurement precision
If a user checks ink discharge by naked eye repeatedly, then alignment can be verified, but the process takes a lot of time and may be inaccurate
Solution Approach 1:
The imaging device captures images of the test pattern and discharge marks on the substrate, providing objective visual feedback for alignment verification. The processing unit automatically analyzes these images to determine whether discharge positions are accurate, replacing subjective naked-eye inspection with precise automated measurement.
Solution Approach 2:
The patent replaces the manual naked-eye inspection method with an automated imaging and image processing system. The imaging device and processing unit automatically measure and evaluate discharge position accuracy, eliminating the need for repeated manual verification and significantly reducing verification time while improving precision.
5Strength
If the glass for ink discharge test has thickness of about 0.5 mm, then the glass provides structural support, but the height of the Z axis of the gantry must be changed every test to prevent nozzle collision
Solution Approach 1:
The patent removes the glass for ink discharge test from the system entirely. Alignment and verification are performed using test patterns and marks directly on the substrate combined with imaging device feedback, eliminating the need for external test substrates with thickness that would require gantry height adjustments.
Solution Approach 2:
The substrate itself serves multiple functions: it is both the final product carrier and the test pattern carrier for alignment verification. The test pattern is printed directly on the substrate, allowing alignment verification to be performed on the substrate itself without requiring separate test glasses or repeated gantry height adjustments.
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 solution enables accurate and efficient alignment of the inkjet head over the entire substrate area, preventing substrate damage and significantly reducing alignment time, thereby enhancing the precision and speed of liquid drop placement.
Implementation Method 1
a laser unit coupled to the inkjet head, and emitting an aiming laser beam by which a discharged position of a liquid drop from the inkjet head to each of the pixels is aimed
Implementation Method 2
a camera capturing an emitted position of the aiming laser beam on the substrate
Data Source
AI summary
A liquid drop discharge apparatus is proposed. The liquid drop discharge apparatus includes: an inkjet head discharging ink to each of pixels of a substrate; a laser emitter coupled to the inkjet head, and emitting an aiming laser beam by which a discharged position of a liquid drop from the inkjet head to each of the pixels is aimed; a camera capturing an emitted position of the aiming laser beam on the substrate; and a position alignment unit aligning a position of the inkjet head on the basis of image data obtained from the shooting unit.