Light Diffusing Polymer Substrate with Nanoparticle Roughness
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Solution Overview
Problem
The existing methods for creating light diffusing articles with surface topography, such as molding transparent polymers, require custom tooling and face challenges in generating arbitrary patterns and gradients in light diffusing properties, which are costly and complex to fabricate.
Innovation Solution
A method involving a polymer substrate with nanoparticles on its surface, where intense pulsed light is used to roughen specific areas, creating controlled surface roughness and diffusing properties without the need for custom tooling, allowing for arbitrary patterns and gradients in light diffusing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If molding is used to create light diffusing surface topography, then light diffusing properties are achieved, but custom tooling is required for each design which increases fabrication cost and complexity
Solution Approach 1:
The patent replaces the mechanical molding system with a photochemical system. Instead of using structured tooling to physically imprint surface topography, the invention uses photomasks and light exposure to selectively crosslink polymer regions, creating varying surface roughness and light diffusing properties through chemical changes rather than mechanical contact.
Solution Approach 2:
The patent uses photomasks as templates to copy desired patterns onto the polymer substrate. The photomask contains the design pattern that is transferred through selective light exposure, allowing arbitrary patterns to be replicated without requiring custom mechanical tooling for each design.
2Adaptability or versatility
If molding is used to generate arbitrary patterns of light diffusing properties, then design flexibility is achieved, but each new design requires new structured tooling which increases fabrication cost
Solution Approach 1:
The patent makes the manufacturing system dynamic and reconfigurable. Instead of fixed mechanical tooling, the system uses software-controlled photomasks that can be changed between production runs. This allows arbitrary patterns to be generated by simply changing the digital design and corresponding photomask, without requiring new physical tooling for each design.
Solution Approach 2:
The patent changes the manufacturing approach from mechanical parameter fixation (mold cavity geometry) to optical parameter control (light exposure patterns). By controlling which regions receive light exposure and to what extent, arbitrary patterns of crosslinking and surface roughness can be created, enabling design flexibility without retooling costs.
3Manufacturing precision
If structured tooling is used to impart gradient in light diffusing properties, then gradient control is achieved, but fabrication challenges increase
Solution Approach 1:
The patent uses controlled light exposure patterns to create gradients in crosslinking density and surface roughness. By varying the intensity, duration, or pattern of light exposure across different regions of the substrate, precise control over gradient properties is achieved through temporal and spatial modulation of the photochemical reaction.
Solution Approach 2:
The patent introduces light as an intermediary to transfer the desired gradient pattern from the photomask to the polymer substrate. The light acts as a mediator that selectively activates crosslinking in specific regions, creating gradient structures without requiring complex gradient tooling surfaces.
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 enables the production of light diffusing articles with controlled surface roughness and diffusing properties, reducing fabrication costs and complexity while enabling arbitrary patterns and gradients, suitable for applications like backlit displays and luminaires.
Implementation Method 1
light absorbing nanoparticles arranged on at least a portion of the first major surface of the substrate; illuminating the portion including at least some of the light absorbing nanoparticles to roughen the polymer
Implementation Method 2
illuminating the portion including at least some of the light absorbing nanoparticles to roughen the polymer in the portion of the first major surface
Data Source
AI summary
Article (9,19) comprising a substrate (10, 20) comprising a polymer and having first (11,21) and second (12, 22) opposed major surfaces. The first major surface (11, 21) has first surface regions (13, 23) with first nanoparticles (14a, 14b, 14c, 14d, 24a, 24b, 24c, 24d) partially embedded into the first major surface (11, 21), and one of •(a) second surface regions (15) free of nanoparticles; or •(b) second surface regions (25) with at least second nanoparticles (28) on the first major surface (11, 21) or partially embedded into the first major surface (11, 21). The first surface regions (13, 23) have a first average surface roughness, Ra1, of at least 20 nm, wherein the second surface regions (15, 25) have a second average surface roughness, Ra2, of less than 100 nm, wherein the first average surface roughness, Ra1, is greater than the second average surface roughness, Ra2, and wherein there is an absolute difference between the first and second average surface roughness of at least 10 nm.