Relief Image Edge Profile via Backside Exposure
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Solution Overview
Problem
Existing methods for producing relief images using liquid photopolymerizable resins often result in sharp edges, which are undesirable in applications such as signage and bronze casting where rounded or smooth edges are preferred.
Innovation Solution
A method involving casting a liquid photopolymerizable resin layer onto a coverfilm, laminating a substrate, placing an image or film negative on top, and exposing the resin from the backside to selectively crosslink and cure the resin, ensuring the depth of the cured relief image is less than the height of the cast resin, thereby producing relief images with rounded or smooth edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the liquid photopolymerizable resin is exposed to actinic radiation to selectively crosslink and cure the resin, then the relief image is formed, but sharp edges are created at the top surface and sidewall intersections
Solution Approach 1:
The patent applies partial action by controlling the exposure parameters (intensity, duration, wavelength) to cure only a portion of the resin depth. This selective curing creates a gradient where the top portion remains uncured while the bottom portion cures, eliminating sharp edges at the interface between cured and uncured regions.
Solution Approach 2:
The patent changes physical parameters of the photopolymerization process, specifically adjusting exposure intensity, duration, and wavelength to control the depth and extent of curing. By modifying these parameters, the cure penetrates only partially through the resin layer, creating smooth transitional edges rather than sharp boundaries.
2Length of stationary object
If the resin layer is cast to a certain height and fully cured, then the relief image depth is maximized, but sharp edges form at the intersection of the top surface and sidewalls
Solution Approach 1:
Instead of fully curing the entire resin layer depth, the patent applies partial curing by controlling exposure parameters to penetrate only a portion of the resin height. This creates a depth gradient where the relief image maintains substantial depth while the uncured portion at the top eliminates sharp edge formations at the sidewall-top surface intersections.
3Productivity
If conventional exposure methods are used, then the relief image is formed efficiently, but the edges are sharp rather than rounded
Solution Approach 1:
The patent modifies exposure parameters (intensity, duration, wavelength distribution) to achieve partial curing. This parameter adjustment maintains production efficiency by using optimized exposure settings that cure the resin sufficiently for structural integrity while preventing complete penetration that would create sharp edges, thus achieving both efficiency and desired edge profiles.
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 method effectively produces relief images with rounded or smooth edges, reducing sharp edges at the top surface and sidewall intersections, suitable for applications requiring such edge profiles.
Implementation Method 1
The liquid photopolymerizable resin is selectively cross-linked and cured to form a printing image surface that mirrors the image on the negative. Upon exposure to actinic radiation, the liquid photopolymerizable resin polymerizes and changes from a liquid state to a solid state to form the raised relief image.
Data Source
Figure 1~2
AI summary
A method of producing a relief image from a liquid photopolymerizable resin, said method comprising the steps of; a) placing a coverfilm onto an exposure glass; b) casting a liquid photopolymerizable resin layer onto the coverfilm; c) laminating a substrate to a backside of the liquid photopolymerizable resin layer as the liquid photopolymerizable resin layer is being cast onto the coverfilm; d) placing an image or film negative on top of the substrate; and e) exposing the liquid photopolymerizable resin layer through the image or film negative from the backside of the liquid photopolymerizable resin layer to selectively crosslink and cure the photopolymerizable resin layer and form a cured relief image, wherein said depth of the cured relief image is less than the height of the cast liquid photopolymerizable resin.