Optical Laminate Stabilizes Wavelength Shift via Phase Adjustment
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Solution Overview
Problem
Wavelength selective reflective elements, such as cholesteric liquid crystal layers, exhibit a short wavelength shift when viewed from oblique angles, leading to inconsistent color perception.
Innovation Solution
An optical laminate comprising a wavelength selective reflective element and an absolute phase adjustment layer with regions of different optical path lengths, arranged in a diffraction grating-like pattern, to interfere and stabilize the reflected light, preventing wavelength shift across viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wavelength selective reflective element (such as cholesteric liquid crystal layer) is used, then light in a specific wavelength region can be selectively reflected, but the reflected wavelength shifts to shorter wavelengths when viewed from oblique angles
Solution Approach 1:
An absolute phase adjustment layer is introduced as an intermediary between the wavelength selective reflective element and the incident light. This layer contains a diffraction grating that modifies the phase of incident light before it reaches the reflective element, thereby compensating for the wavelength shift that occurs during oblique viewing and maintaining consistent color perception across different viewing angles.
Solution Approach 2:
The invention changes the optical parameters of the system by introducing a phase adjustment layer with specific optical path length variations. The diffraction grating in this layer creates controlled phase differences that counteract the wavelength shift effect, transforming the optical behavior of the overall laminate to maintain wavelength consistency despite viewing angle changes.
2Stability of the object's composition
If an absolute phase adjustment layer with diffraction grating pattern is added, then wavelength shift is suppressed and color consistency is improved, but device complexity increases
Solution Approach 1:
The phase adjustment function is extracted as a separate, dedicated layer with a specific diffraction grating pattern. By isolating this function in a distinct layer rather than integrating it into the wavelength selective reflective element itself, the design maintains modularity and simplifies the overall structure while achieving the desired wavelength consistency.
Solution Approach 2:
The optical laminate is constructed as a composite structure combining the wavelength selective reflective element with an absolute phase adjustment layer containing a diffraction grating. This composite approach allows each layer to perform its specific function independently, achieving wavelength consistency without significantly increasing overall device complexity through functional integration.
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 optical laminate effectively suppresses wavelength shift, maintaining consistent color perception from normal and oblique viewing angles by utilizing interference between light components with different optical path lengths, ensuring stable reflection within a specific wavelength region.
Implementation Method 1
A cholesteric liquid crystal which is a type of wavelength selective reflective element has a property of selectively reflecting specific circularly polarized light of a specific wavelength
Implementation Method 2
light which enters the first region and is reflected by the wavelength selective reflective element and light which enters the second region and is reflected by the wavelength selective reflective element interfere with each other
Implementation Method 3
a first region having a first optical path length and a second region having a second optical path length different from the first optical path length are arranged in a pattern with a diffraction grating-like period
Data Source
AI summary
An optical laminate includes a wavelength selective reflective element, and an absolute phase adjustment layer which is provided on at least one surface side of the wavelength selective reflective element and has optical isotropy, and in which a first region having a first optical path length and a second region having a second optical path length different from the first optical path length are arranged in a pattern with a diffraction grating-like period. The optical laminate reflects light in the specific reflection wavelength region by the wavelength selective reflective element, of light incident from the absolute phase adjustment layer side. In the optical laminate, light which enters the first region of the absolute phase adjustment layer and is reflected by the wavelength selective reflective element and light which enters the second region and is reflected by the wavelength selective reflective element interfere with each other.