Variable-Transmittance Optical Filter With Color-Balancing Layers
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Solution Overview
Problem
Existing variable transmittance optical filters struggle with achieving a desired color balance and light transmission in both faded and dark states, often resulting in distorted colors due to the inherent color of the transmittance materials, which cannot be easily altered while maintaining variable transmittance properties.
Innovation Solution
Incorporating a color balancing layer with a variable transmittance layer to achieve a target color, using a multi-layer composition that includes a switching material transitionable between states by electromagnetic radiation and voltage, and optionally a light attenuating layer to fine-tune light transmission and color.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a variable transmittance layer is used to control light transmission, then light transmission can be adjusted between faded and dark states, but the color becomes distorted due to the inherent color of the transmittance materials
Solution Approach 1:
The optical filter is divided into separate functional layers: a variable transmittance layer for controlling light transmission and a color balancing layer for correcting color distortion. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between adjustable light transmission and color accuracy.
Solution Approach 2:
The patent combines multiple materials with different properties into a composite structure. The variable transmittance layer (which may be blue, green, or other colored materials) is combined with a color balancing layer containing complementary colorants. This composite approach allows the system to maintain both the variable transmittance properties and achieve neutral color balance in the faded state.
2Manufacturing precision
If the color of the variable transmittance filter is changed to achieve desired appearance, then color balance may improve, but the variable transmittance properties cannot be easily maintained
Solution Approach 1:
By separating color control into a dedicated color balancing layer, the patent allows manufacturers to adjust colors without affecting the variable transmittance mechanism. The variable transmittance layer can be optimized for switching performance while the color balancing layer handles color correction, making manufacturing easier.
Solution Approach 2:
The color balancing layer acts as an intermediary between the variable transmittance layer and the external environment. It compensates for the color of the variable transmittance layer without interfering with its electrochromic or photochromic switching properties, allowing independent optimization of both functions.
3Illumination intensity
If additional visible light filters are included to attenuate transmitted light, then light transmission can be reduced, but color distortion is exacerbated
Solution Approach 1:
Instead of using a single filter that attenuates all wavelengths equally, the patent employs a color balancing layer with specific spectral characteristics that selectively compensates for color distortion while allowing controlled light attenuation. The layer is designed to transmit certain wavelengths preferentially to maintain color accuracy.
Solution Approach 2:
The color balancing layer is constructed as a composite material that combines light attenuation properties with color correction properties. This allows the layer to simultaneously reduce overall light transmission while maintaining or improving color balance, unlike conventional single-function filters.
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 allows for precise color balancing to achieve neutral or target colors in both states, enhancing the appearance and functionality of optical filters in automotive and architectural applications by adjusting light transmittance and reducing color distortion.
Implementation Method 1
Some photochromic materials may darken in response to light, frequently ultraviolet light, and may return to a faded state when the UV light is removed or reduced.
Implementation Method 2
Some electrochromic materials may darken in response to application of a voltage, and may return to a faded state once the voltage is removed; alternately, some electrochromic materials may darken in response to application of a voltage of a first polarity, and fade when a voltage of an opposite polarity is applied.
Implementation Method 3
a color balancing layer having a spectrum; each spectrum comprising an ultraviolet (UV) portion, a visible portion and an infra-red (IR) portion; and the spectra of the layers combining to provide a color of the optical filter approximating a target color
Data Source
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AI summary
A optical filter comprising a variable transmittance layer having a first spectrum in a dark state, and a second spectrum in a faded state; and a color balancing layer having a third spectrum; each of the first, second and third spectra comprising a visible portion; the first and third spectra combining to provide a dark state spectrum approximating a dark state target color; and the second and third spectra combining to provide a fades state spectrum approximating a faded state target colour. The optical filter may further comprise a light attenuating layer. The optical filter may further comprise part of a laminated glass.