Digital Mask Panel for Flexographic Print Master Creation
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Solution Overview
Problem
Current methods for creating flexographic print masters are inefficient due to the need for separate equipment and additional production steps in traditional plate making processes, and three-dimensional printing methods are complex and expensive, with issues in controlling the shape and thickness of layers formed by jetting UV-curable ink droplets.
Innovation Solution
A two-dimensional transparent light valve array driven by a raster image processor is used to create a digital contact mask, eliminating the need for additional equipment and simplifying the process by providing a solid-state digital contact mask with high contrast ratio and small pixel size, suitable for exposing a printing plate precursor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional plate making process with separate equipment and chemical development is used, then the process can create flexographic print masters, but the device complexity and production time increase
Solution Approach 1:
The patent combines the mask creation and plate exposure functions into a single integrated device. The liquid crystal display panel serves as both the digital mask and the exposure medium, eliminating the need for separate film processing equipment, chemical development tanks, and multiple exposure devices. This merging of functions directly reduces device complexity and streamlines the manufacturing process.
Solution Approach 2:
The patent replaces mechanical and chemical processes with electronic and optical systems. Instead of using physical film masks that require mechanical handling and chemical development, the invention uses a liquid crystal display panel controlled by digital signals. The LCD panel can be electronically programmed to create the desired mask pattern without any physical mask creation or chemical processing steps.
2Ease of manufacture
If three-dimensional printing with UV-curable ink droplets is used, then flexographic print masters can be created, but the manufacturing precision of layer shape and thickness is poor
Solution Approach 1:
The patent replaces the three-dimensional printing process with a two-dimensional photolithography approach using an LCD panel. Instead of jetting UV-curable ink droplets layer by layer, the invention uses a flat LCD panel to selectively expose a photopolymer coating through a digital mask pattern. This eliminates the precision problems associated with droplet placement and layer stacking, as the entire relief structure is created in a single exposure step with precise digital control over the exposed areas.
Solution Approach 2:
The patent creates a direct digital copy of the desired print master pattern on the LCD panel without requiring physical layer-by-layer construction. The digital image data is directly transferred to the LCD panel, which then exposes the photopolymer material to create an exact replica of the intended relief structure. This copying approach eliminates the accumulation of errors that occur in iterative layer-by-layer printing processes.
3Ease of manufacture
If liquid crystal display panel with large pixel size is used, then the device can be manufactured, but the measurement precision and image quality deteriorate
Solution Approach 1:
The patent specifies precise parameter ranges for the LCD panel to achieve optimal performance. The pixel pitch is constrained to 40 μm or smaller, and the contrast ratio in the UV-A spectrum must exceed 20/1. These parameter specifications ensure that the pixel size is small enough to produce high-resolution halftone images while remaining compatible with standard LCD manufacturing capabilities. The patent also specifies the spectral characteristics of the light source and panel transmission to optimize the exposure process.
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 reduces the complexity and cost of creating flexographic or offset print masters by eliminating the need for separate equipment and chemical waste, while achieving high-quality halftone images with improved ink accepting properties and reduced operational time.
Implementation Method 1
said panel comprises a two-dimensional array of pixels of which the transparency can be individually switched between a first level and a second level that is lower than the first level
Implementation Method 2
The sheet is exposed by means of a UV light source through the negative film which acts like a mask. The effect of this is that the portions of the polymerizable sheet underneath the transparent parts of the film selectively polymerize under influence of the UV-A light
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A digital mask panel suitable for exposing a printing plate precursor, the panel comprising a two-dimensional array of elements (411) of which the transparency can be individually switched between a first level and a second level that is lower than the first level, the ratio of the first over the second level defining a contrast ratio that exceeds 20/1 in the UV-A part of the electromagnetic spectrum. A transistor for each element (411) of the array is positioned in the middle of the element (FIG. 6B).