Photosensitive Element Polypropylene Protective Film Lamination
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Solution Overview
Problem
Conventional photosensitive elements with thin photosensitive layers often form air bubbles during lamination, which can impair the reliability of electronic components such as insulating films and touch panels.
Innovation Solution
A photosensitive element with a polypropylene film having smooth surfaces on both sides, which suppresses the transfer of unevenness from the protective film to the photosensitive layer, thereby reducing air bubble formation during lamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional photosensitive element with a protective film is used, then the photosensitive layer can be laminated on a substrate, but air bubbles are formed in the laminate when the photosensitive layer is thin
Solution Approach 1:
The protective film is designed with different surface roughness values for its two surfaces: the first surface (contacting the photosensitive layer) has Ra = 0.05 to 0.5 μm to prevent air bubble formation, while the second surface (opposite side) has Ra = 0.1 to 1.0 μm for other functional requirements. This local differentiation resolves the contradiction by optimizing the lamination interface quality without compromising the protective film's overall performance.
Solution Approach 2:
The invention changes the surface roughness parameter of the protective film's first surface to a specific range (Ra = 0.05 to 0.5 μm), which is lower than the conventional single-sided or double-sided rough surfaces. This parameter optimization allows the protective film to maintain its protective function while preventing air bubble formation during lamination of thin photosensitive layers.
2Ease of operation
If the surface roughness of the protective film is increased to enhance followability to uneven substrates, then the protective film conforms better to the substrate, but the shape of the protective film is transferred to the photosensitive layer causing air voids
Solution Approach 1:
The protective film is designed with different surface roughness values for its two surfaces: the first surface (contacting the photosensitive layer) has Ra = 0.05 to 0.5 μm to prevent shape transfer and air void formation, while the second surface (opposite side) has Ra = 0.1 to 1.0 μm that can provide followability to uneven substrates. This local differentiation resolves the contradiction by decoupling the two conflicting requirements.
Solution Approach 2:
Instead of making the surface contacting the photosensitive layer rough to improve substrate followability, the invention makes it smooth (Ra = 0.05 to 0.5 μm) to prevent shape transfer, while providing the rough surface (Ra = 0.1 to 1.0 μm) on the opposite side for substrate conformability. This inverted approach resolves the contradiction by reversing the conventional wisdom.
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 effectively prevents air bubble occurrence even with thin photosensitive layers, enhancing the reliability of electronic components by ensuring a smooth lamination process and maintaining the integrity of the resist pattern.
Implementation Method 1
a predetermined portion of the photosensitive layer is irradiated with active rays from the support film side to form a photo-cured portion (light exposure step)
Data Source
AI summary
A photosensitive element 1 comprises a support film 10, a protective film (polypropylene film) 30, and a photosensitive layer 20 which is arranged between the support film 10 and the protective film 30, wherein the protective film 30 has a principal surface 30a at a side of the photosensitive layer 20 and a principal surface 30b at an opposite side of the principal surface 30a, and the principal surface 30a and the principal surface 30b are smooth.