Color Display Guided-Mode Resonance for Reflectance and Resolution
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Solution Overview
Problem
Existing color displays face challenges in achieving high resolution and rich color expression while maintaining visibility due to reduced reflectance from diverse pixel structures and increased pixel size, which compromises both resolution and designability.
Innovation Solution
A color display configuration comprising an embossed layer, a high refractive index layer, and a protective layer, with specific periodic structures and orientations to enhance guided-mode resonance, allowing for controlled emission of zeroth-order and first-order diffracted light, and incorporating authentication codes for machine-readable verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If arbitrary structures are provided in multiple pixels to achieve rich color expression, then designability is improved, but reflectance is reduced which reduces visibility
Solution Approach 1:
The pixel structure is divided into multiple regions (first region with periodic structure, second region without periodic structure, third region with different periodic structure) that perform different functions. This segmentation allows each region to be optimized independently - the periodic structure regions provide color expression while the non-periodic region maintains high reflectance, resolving the contradiction between designability and visibility
Solution Approach 2:
Different regions within the pixel are assigned different structural properties: the first and third regions have periodic structures for color expression, while the second region has no periodic structure for high reflectance. This local differentiation allows the pixel to simultaneously achieve both rich color expression and high visibility through coordinated regional functions
2Illumination intensity
If pixel size is increased to increase reflectance per unit pixel, then reflectance is improved, but resolution is reduced
Solution Approach 1:
The pixel is segmented into multiple functional regions, allowing the periodic structure regions to be made smaller for high resolution while the non-periodic region compensates for reflectance. This enables maintaining small pixel sizes for high resolution while achieving sufficient reflectance through the coordinated action of multiple regions
Solution Approach 2:
Multiple regions with different reflectance characteristics are combined within a single pixel. The non-periodic region (second region) provides high reflectance that compensates for the smaller size of periodic structure regions, enabling high resolution pixels to achieve sufficient overall reflectance through the combined effect of all regions
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 enhances light intensity, increases resolution, and enables rich color expression with high designability, while providing a means for authenticity determination through machine-readable authentication codes.
Implementation Method 1
When light is incident on the sub-wavelength grating, reflection of light due to guided-mode resonance occurs while suppressing reflection of diffracted light into a space on the incident light side. Guided-mode resonance is a phenomenon in which light in a specific wavelength band propagates through multiple reflections in an optical device, causing resonance so that light in the specific wavelength band is reflected by the optical device as reflected light with high intensity.
Implementation Method 2
a diffraction direction is controlled by the arrangement of diffraction gratings to determine a pixel region that causes a diffraction phenomenon according to the observation angle, so that an image changes depending on the observation angle
Data Source
AI summary
A color display of an embodiment includes: an embossed layer; a high refractive index layer; and a protective layer, laminated in this order, wherein the high refractive index layer has a highest refractive index among these layers, the embossed layer includes a first region having a periodic structure with a period at least smaller than a center wavelength of visible light, a plurality of the first regions, each having a strip shape, are connected to each other at their longitudinal end sides, the first regions being offset from each other in a direction perpendicular to a longitudinal direction of the strip shape, as viewed via a display surface, and a periodic direction of the periodic structure is parallel to the longitudinal direction.