Variable Light Transmittance Element Using Metal Nanoparticles
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Solution Overview
Problem
Conventional color filters in liquid crystal display devices have low transmittance efficiency and require complex manufacturing processes, leading to increased power consumption and manufacturing challenges.
Innovation Solution
A variable light transmittance element comprising a transparent semiconductor material with dispersed metal nanoparticles, electrically connected to electrodes, and an insulating layer, where the conductivity of the semiconductor material is controlled by voltage to change the localized surface plasmon resonance state, thereby adjusting light transmittance and color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional color filters use dyes or pigments to absorb and dissipate light of unnecessary color, then color filtering function is achieved, but transmittance efficiency becomes low and power consumption increases
Solution Approach 1:
The patent changes the fundamental mechanism from absorption to scattering by altering the physical state of the filtering medium. Instead of using dyes that absorb light, the invention uses metal nanoparticles that scatter light through localized surface plasmon resonance, thereby reducing energy loss while maintaining color filtering functionality
Solution Approach 2:
The patent replaces the chemical absorption mechanism of dyes with a physical scattering mechanism based on electromagnetic interaction. The metal nanoparticles interact with the electric field of light to scatter unwanted wavelengths, substituting chemical energy dissipation with physical electromagnetic scattering
2Reliability
If conventional color filters apply, expose, develop, and cure color resist for each primary color repeatedly, then color filtering is achieved, but manufacturing process becomes complicated
Solution Approach 1:
The patent merges multiple separate color filter manufacturing steps into a single process. By forming a single layer containing metal nanoparticles that can filter multiple wavelengths simultaneously, the invention eliminates the need for repeated application, exposure, development, and curing steps for each primary color
Solution Approach 2:
The patent creates a universal filtering layer that performs multiple color filtering functions simultaneously. The metal nanoparticle layer can filter multiple wavelengths and colors in one structure, replacing the need for separate color resist processes for each primary color
3Illumination intensity
If metal nanoparticles are dispersed in transparent non-conductive medium to achieve color through LSPR, then color varies with particle size and spacing, but control precision is limited
Solution Approach 1:
The patent replaces mechanical control of particle spacing with electrical control of conductivity. Instead of precisely controlling the physical distance between nanoparticles during manufacturing, the invention uses voltage control to adjust the conductivity of the medium, which in turn controls the LSPR effect and color output
Solution Approach 2:
The patent changes the control parameter from physical particle spacing to electrical conductivity. By applying voltage to change the conductivity state of the transparent semiconductor material, the LSPR resonance conditions are modified, allowing dynamic control of color without changing the physical arrangement of nanoparticles
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 variable light transmittance element allows for flexible control of light transmittance and color, enhancing display quality and transparency, and can be applied to both conventional display devices and transparent information displays like smart windows.
Implementation Method 1
When a transparent non-conductive medium contains metal nanoparticles, it can have color. This is attributable to a phenomenon called localized surface plasmon resonance (LSPR). In brief, free electrons inside metal nanoparticles interact with the electric field of light (electromagnetic waves), in which case light of a specific wavelength at which resonance occurs is absorbed and scattered to give color as a whole.
Implementation Method 2
the conductivity of the transparent semiconductor material included in the variable light transmittance layer is controlled by applying a voltage to the variable light transmittance stack structure, so that a localized surface plasmon resonance (LSPR) state of the metal nanoparticles is changed
Data Source
AI summary
The present invention relates to a variable light transmittance element including a variable light transmittance structure, wherein the variable light transmittance structure includes: a first electrode; a variable light transmittance layer made of a transparent semiconductor material in which metal nanoparticles are dispersed, and electrically connected to the first electrode; a second electrode; and an insulating layer interposed between the variable light transmittance layer and the second electrode, and also relates to a color filter for a display device and smart window including the same. The variable light transmittance element according to the present invention induces a change in the localized surface plasmon resonance (LSPR) state by applying a voltage to both ends of the variable light transmittance stack structure including the electrode/insulation layer/metal nanoparticle-containing transparent semiconductor layer, and thus the light transmittance and color of the metal nanoparticle-containing transparent semiconductor layer may be freely changed.