Inkjet Printing Head Alignment Using CCD Sensing
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Solution Overview
Problem
As the size of mother glass substrates for display devices increases, the alignment of inkjet heads in inkjet printing systems becomes more time-consuming and inefficient, affecting the precision and speed of forming color filters and light emitting members.
Innovation Solution
An inkjet printing system with a mother glass stage and alignment key position sensing unit, utilizing CCD cameras to generate sensing signals for precise alignment of the head unit, allowing for accurate deposition of ink or materials onto substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of mother glass substrates is increased to produce larger display devices, then the production capacity and panel size are improved, but the alignment time and complexity increase significantly
Solution Approach 1:
The patent divides the large mother glass substrate into multiple smaller substrates, each with its own alignment keys. This segmentation allows the alignment system to handle multiple smaller areas simultaneously rather than one large area, reducing the overall alignment time while maintaining the capability to produce large display devices through batch processing
Solution Approach 2:
Alignment keys are pre-formed on each substrate before the inkjet printing process begins. The sensing unit detects these pre-positioned keys to establish reference points for the head unit, eliminating the need for complex real-time alignment calculations during the printing process itself
2Productivity
If the number of cells on mother glass is increased to maximize substrate utilization, then the production efficiency is improved, but the alignment complexity and time consumption increase
Solution Approach 1:
Each substrate contains its own alignment keys that automatically provide reference information when detected by the sensing unit. This self-service mechanism eliminates the need for complex external alignment procedures, allowing multiple cells to be aligned independently and simultaneously, thereby maintaining high productivity without increasing alignment complexity
Solution Approach 2:
The patent transforms the alignment problem from a complex multi-variable calculation into a simpler detection task by changing the reference parameter from relative positioning to absolute key detection. The sensing unit detects the positions of alignment keys as fixed reference points, simplifying the alignment control parameters needed for each additional cell
3Device complexity
If manual or conventional alignment methods are used for large mother glass substrates, then the system complexity is kept low, but the alignment precision and speed deteriorate
Solution Approach 1:
The patent replaces manual or mechanical alignment methods with an optical sensing system using CCD cameras. This substitution provides automated, high-precision detection of alignment key positions, achieving superior alignment precision and speed while keeping the overall system relatively simple through the use of standard sensing components
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 significantly reduces the time required for alignment and enhances the precision of forming color filters and light emitting members, improving manufacturing efficiency and reliability while decreasing costs.
Implementation Method 1
an alignment key position sensing unit for sensing positions of the alignment keys to generate a plurality of sensing signals respectively corresponding to the alignment keys
Data Source
AI summary
An inkjet printing system is provided, which includes a first stage mounted with a mother glass including a plurality of substrates and a plurality of alignment keys, a head unit having at least one inkjet head, an alignment key position sensor for sensing positions of the alignment keys to generate a plurality of sensing signals respectively corresponding to the alignment keys, and a transporting unit controller for aligning a position of the head unit based on a current position of the head unit and positions determined by the corresponding sensing signals with respect to the corresponding alignment keys.