Optical body, window material, and roll curtain
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Solution Overview
Problem
Existing laminated structures for shielding solar radiation specularly reflect sunlight, contributing to increased air temperatures and exacerbating the heat island effect, as they reflect sunlight towards buildings and the ground, rather than effectively directing it away.
Innovation Solution
An optical body with a directional reflection performance is developed, featuring a depression-protrusion shape in its transparent layers and a wavelength-selective reflecting layer, which selectively reflects near-infrared light back towards the sky, reducing heat absorption and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a laminated structure for shielding against solar radiation is affixed to flat window glass, then solar radiation shielding performance is improved, but specular reflection of sunlight causes heat island effect to worsen
Solution Approach 1:
The patent applies curvature to the window glass surface, transforming flat glass into curved glass. This curvature changes the reflection pattern of sunlight from specular reflection (which concentrates heat in specific directions) to diffuse reflection (which scatters heat in multiple directions). The curved surface maintains solar radiation shielding performance while eliminating the heat island effect by redirecting reflected sunlight away from surrounding areas.
Solution Approach 2:
The patent changes the geometric parameter of the window glass from flat to curved. This parameter change fundamentally alters the optical behavior of the laminated structure, transforming it from a solar shield that creates heat concentration to one that provides both shielding and heat dispersion. The curvature radius and profile can be optimized to control the reflection pattern.
2Object-generated harmful factors
If optical body with directional reflection is used, then heat island effect mitigation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the directional reflection function into the window glass itself by making the glass curved, rather than adding a separate complex optical body. This integration achieves heat island effect mitigation through the glass geometry while avoiding the complexity of additional optical components. The laminated structure and curved glass work together as a unified system.
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 body effectively directs near-infrared light back towards the sky, reducing heat absorption and cooling loads, thereby mitigating the heat island effect and improving energy efficiency while maintaining transparency for visible light.
Implementation Method 1
a wavelength-selective reflecting layer 3 which selectively reflects near-infrared light back towards the sky
Implementation Method 2
causes directional reflection of the light in a direction other than a specular reflection direction
Data Source
Figure 1A~1B
Figure 2
Figure 3A
AI summary
An optical body includes a first optical transparent layer having quadrangular pyramid-shaped depressions, a wavelength-selective reflecting layer formed on the depressions and selectively reflecting light of a specific wavelength band, and a second optical transparent layer formed on the wavelength-selective reflecting layer. When (θ, φ) is taken as the incident angle (θ: angle between perpendicular line relative to second optical transparent layer acting as incident surface and light incident on incident surface; φ: angle between specific straight line within incident surface and component resulting from projection of incident light on incident surface), with respect to incident light that is incident on the incident surface from different φ directions at θ = 60°, the optical body has an average reflection angle of reflected light to the same quadrant as the incident light of 30° or more.