Optical Sheet Manufacturing Resolving Streaky Unevenness
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Solution Overview
Problem
Existing methods for manufacturing optical sheets result in streaky unevenness due to excessive binder and light-absorbing particles, leading to poor appearance and surface quality, which negatively affects the optical sheet's performance when laminated with other layers.
Innovation Solution
A method involving the stepwise reduction of light-absorbing particle density in the binder, followed by coating with a transparent resin, or using a mirror-surface imprint mold to fill recess portions, to improve the optical sheet's appearance and surface smoothness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the binder and light-absorbing particles are filled in the optical functional sheet while raising the density of the light-absorbing particles dispersed in the binder step-by-step, then the light-absorbing function is improved, but the appearance becomes poor due to streaky unevenness
Solution Approach 1:
The patent applies preliminary action by first filling the binder with a certain density of light-absorbing particles, then performing a strickling step to remove excessive particles before adding more binder and particles. This preliminary removal of excessive particles prevents the formation of streaky unevenness that would occur if particles were simply added in increasing densities without intermediate processing.
Solution Approach 2:
The patent segments the filling process into multiple discrete steps, where each step involves adding binder with light-absorbing particles, followed by a strickling step to remove excessive material. This segmentation allows control over particle distribution and prevents the accumulation of streaky unevenness that would result from continuous high-density filling.
2Reliability
If excessive binder and light-absorbing particles are strickled, then the light-absorbing density is improved, but the binder is dragged and removed causing streaky unevenness
Solution Approach 1:
The patent applies parameter changes by carefully controlling the density of light-absorbing particles in the binder at each filling step. Instead of using excessively high particle density that would require aggressive strickling, the method uses moderate densities that achieve sufficient light-absorbing function while minimizing binder removal and streak formation during the strickling process.
3Reliability
If the density of light-absorbing particles is increased to improve external light shielding, then the shielding function is enhanced, but the surface appearance deteriorates due to protruding particles
Solution Approach 1:
The patent performs preliminary strickling steps after each binder filling operation to remove light-absorbing particles that protrude from the surface. This preliminary removal prevents surface irregularities before the next layer or processing step, ensuring that high particle density for light shielding does not compromise surface smoothness.
Solution Approach 2:
The patent segments the high-density particle filling into multiple lower-density steps, each followed by strickling. This segmentation achieves the cumulative light-absorbing effect of high density while maintaining surface smoothness through intermediate removal of protruding particles at each stage.
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 method produces an optical sheet with improved appearance and surface quality, reducing streaky and belt-like unevenness, thereby enhancing the optical sheet's performance and appearance when integrated with other layers.
Implementation Method 1
forming the light-absorbing portions repeatedly by filling a binder made of a resin in which light-absorbing particles are dispersed
Implementation Method 2
coating, with a transparent resin, the surface of the optical functional sheet layer after filling the binder containing the light-absorbing particles
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
The present invention provides an optical sheet having a plurality of layers in which at least one layer is an optical functional sheet layer comprising: light-transmissive portions configured to be arranged in a row along the surface of a base material layer; and light-absorbing portions arranged between the light-transmissive portions. The light-absorbing portions are filled with binder in which light-absorbing particles are dispersed, forming a surface including recess portions between the light-transmissive portions, wherein the surface including the recess portions is coated with a transparent resin that does not include the light-absorbing particles.