Light Control Layer for Angle-Dependent Color Variation
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Solution Overview
Problem
Existing light-emitting devices lack a method to extract light efficiently using a new approach by optimizing the positional relationship between optical elements and a light source, resulting in limited control over light extraction and color variation with angle of view.
Innovation Solution
A light-emitting device comprising a light-transmissive member with a light control layer having reflected-wavelength selectivity, where the light control layer, made of a colloidal crystal film, is disposed on the surface of the light-transmissive member, and the light source emits light towards one end surface, allowing the wavelength of reflected light to depend on the incident angle, thereby varying the extracted light's color with the angle of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional light guide plate or lens is used to extract light, then light extraction is achieved, but the control over light extraction efficiency and color variation with angle of view is limited
Solution Approach 1:
The light control layer is applied only to specific regions of the light-transmissive member surface, creating local variations in optical properties. This allows different areas to control different wavelengths or angles of light extraction, achieving both high extraction efficiency and customizable color variation patterns.
Solution Approach 2:
The patent utilizes the angle-dependent reflective wavelength property of the light control layer, where the reflected wavelength changes as a function of the incident angle. By controlling the layer thickness and refractive index, the system achieves dynamic color variation with viewing angle while maintaining high extraction efficiency at optimal angles.
2Adaptability or versatility
If multiple optical elements are added to improve light extraction control, then color variation control improves, but device complexity increases
Solution Approach 1:
The light control layer serves multiple functions simultaneously: it acts as a wavelength-selective reflector, an angle-dependent color controller, and a light extraction enhancer. This single multi-functional component replaces what would traditionally require multiple separate optical elements, reducing overall device complexity.
Solution Approach 2:
The light control layer is constructed as a composite structure with specific refractive index and thickness properties that enable angle-dependent wavelength selection. This composite material approach integrates multiple optical functions into a single layer, avoiding the need for stacked optical elements and simplifying the overall device architecture.
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 configuration enables efficient extraction of light with specific wavelengths depending on the angle of view, increasing light extraction efficiency and allowing for selective confinement of different wavelengths, effectively changing the emission color and enhancing the device's functionality as both a lighting and optical transmission device.
Implementation Method 1
The light control layer has reflected-wavelength selectivity that makes a wavelength of reflected light dependent on an incident angle of incident light.
Implementation Method 2
the light control layer, made of a colloidal crystal film, is disposed on the surface of the light-transmissive member
Data Source
AI summary
A light-emitting device includes: a light guide that includes (i) a light-transmissive member that is light-transmissive at least in a visible light region and (ii) a light control layer that is disposed on at least a part of a surface of the light-transmissive member; and a light source that emits light toward at least one end surface of the light-transmissive member. The light control layer has reflected-wavelength selectivity that makes a wavelength of reflected light dependent on an incident angle of incident light.