Optical Element Nanostructure Stain Prevention
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Solution Overview
Problem
Conventional optical elements with nanostructures on their front surfaces face handleability issues due to contaminant adhesion and capillary action, leading to stain formation, which affects their optical properties and is not effectively addressed by existing solutions.
Innovation Solution
The optical element features a front surface with projected portions at a pitch equal to or shorter than the wavelength of visible light, designed with a water contact angle of 100° or greater to prevent contaminant adhesion and spreading, utilizing a hydrophobic resin and surface treatment to enhance stain prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective film is applied to the front surface to retain optical properties, then the optical properties are preserved, but contaminants can adhere to the side surface and spread through capillary action forming stains
Solution Approach 1:
The patent applies different surface properties to different regions: the front surface maintains the nanostructure for optical properties while the side surface is treated with a hydrophobic coating to prevent contaminant adhesion. This local differentiation allows each surface to fulfill its specific function without compromising the other.
Solution Approach 2:
A hydrophobic resin coating is introduced as an intermediary substance on the side surface to prevent direct contact between contaminants and the nanostructured base material. This intermediary layer blocks the capillary action that would otherwise allow contaminants to penetrate and form stains.
2Ease of operation
If the front surface is exposed to allow easy cleaning, then contaminant removal is facilitated, but the nanostructure becomes vulnerable to stain formation through capillary action
Solution Approach 1:
The hydrophobic resin coating serves as a protective intermediary that prevents contaminants from adhering to the nanostructure in the first place, eliminating the need for frequent cleaning while maintaining stain resistance.
Solution Approach 2:
The patent converts the potentially harmful capillary action into a beneficial effect by using the same nanostructure principle to create superhydrophobicity on the side surface, causing water and contaminants to bead up and roll off rather than adhere.
3Object-affected harmful factors
If a hydrophobic resin is applied to increase water contact angle, then contaminant adhesion is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The hydrophobic resin is applied in advance during the manufacturing process, before the product is put into service. This preliminary treatment ensures that the side surface is pre-protected against future contaminant adhesion, eliminating the need for subsequent maintenance or complex operational procedures.
Solution Approach 2:
The patent changes the surface energy parameter of the side surface by applying a hydrophobic resin, increasing the water contact angle to prevent contaminant adhesion. This parameter modification is achieved through a straightforward coating process that integrates well with existing manufacturing workflows.
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 design effectively prevents contaminant spreading and stain formation, maintaining the optical element's reflectance and chromaticity properties, and allows easy removal of contaminants, improving handleability and functionality.
Implementation Method 1
The moth-eye structure has a continuously changing refractive index from the air layer to the base material to cause the front surface of the base material to be non-optical for incident light, significantly reducing the reflected light
Implementation Method 2
the nanostructured projections, continuously formed in the film, allow the stain components to spread between the nanostructured projections with time, so that the stain appears to have disappeared
Implementation Method 3
a water-repellent front surface having a contact angle with water of 100° or greater can prevent contaminant components adhering to the edge from spreading through the capillary action
Data Source
AI summary
A optical element prevents a contaminant component adhering to the edge thereof from spreading through the capillary action and thus from forming a stain. A display device includes the element. An optical element includes a front surface provided with projected portions at a pitch equal to or shorter than the wavelength of visible light, the front surface having a contact angle with water of 100° or greater at least at an edge and preferably having a contact angle with hexadecane of 20° to 100° at least at an edge. A display device includes such an optical element.