Angle-Selective Optical Element for Solar Heat Shielding
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Solution Overview
Problem
Existing solutions for reducing solar radiation heating in buildings, such as curtains, solar shades, and tinted glass, either obstruct the view or are inefficient in blocking direct sunlight, especially when the sun is high in the sky, leading to increased energy consumption for cooling.
Innovation Solution
An optical element with transparent and non-transparent areas arranged in a specific pattern to be nearly invisible at typical indoor distances, allowing light from lower angles to pass while blocking light from higher angles, thereby reducing direct solar radiation and maintaining visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If curtains or solar shades are used to block direct sunlight, then solar radiation heating is reduced, but the view from the room is obstructed
Solution Approach 1:
The optical element has different local properties: transparent areas allow light passage for viewing, while non-transparent areas block direct sunlight. This spatial differentiation of optical properties enables simultaneous achievement of heating reduction and view maintenance.
Solution Approach 2:
The optical element is divided into multiple transparent and non-transparent areas arranged in a pattern. This segmentation allows selective blocking of light based on angle of incidence, permitting views in certain directions while blocking sunlight from above.
2Temperature
If tinted glass panes are used to reduce solar radiation, then direct sunlight is blocked, but the view is dimmed and colour perception is disturbed
Solution Approach 1:
Instead of uniform tinting, the optical element has localized non-transparent areas that selectively block sunlight while maintaining transparency in other areas. This preserves light transmission quality and colour perception while reducing solar radiation.
3Temperature
If external awnings or solar shades are used to dim sunlight, then direct radiation is reduced, but the architectural appearance is influenced and maintenance requirements increase
Solution Approach 1:
The optical element merges the sun-shielding function with the window pane structure itself, eliminating the need for separate external awnings or shades. This integration maintains architectural appearance while reducing maintenance requirements.
4Temperature
If Venetian blinds are used to control light angles, then light passage is selectively controlled, but the lamellae are extremely visible and obstruct the view
Solution Approach 1:
The non-transparent areas are distributed sparsely throughout the optical element, creating a pattern that controls light angles while maintaining overall transparency. This prevents view obstruction compared to solid Venetian blind lamellae.
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 element effectively reduces solar radiation heating without obstructing the view, lowering energy consumption and maintaining a uniform appearance, as it appears transparent when viewing objects close to the horizon.
Implementation Method 1
the essentially non-transparent areas are arranged sufficiently close to each other and have a sufficient extent perpendicular to the face for the intermediate transparent areas to have a depth-to-width ratio that causes the optical element to allow, at a given point on the face, light to pass at certain angles of incidence, while light with other angles of incidence are unable to pass the optical element at the relevant point
Data Source
AI summary
An optical element (11) in the form of an at least partially transparent face comprises transparent areas and essentially non-transparent areas. The transparent areas are arranged sufficiently close for the intermediate and essentially non-transparent areas to be essentially invisible to the naked eye, at least when the element is viewed from a given distance. The essentially non-transparent areas are arranged sufficiently close and have a sufficient extent at right angles to the face for the intermediate, transparent areas to have such depth/width ratio that the optical element will, at a given point on the face, allow passage of light with given angles of incidence, while light having other angles of incidence are unable to pass the element at the point in question. Hereby an optical element is obtained that is able to better reduce the heating of the interior of a building that is caused by incoming solar radiation without the direct radiation and hence the view being blocked considerably.