Internal Corrugated Boundaries for Light Redirection
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Solution Overview
Problem
Conventional light directing films rely on external surface microstructures, which lead to soiling issues, complicate surface cleaning, and create air pockets that hinder light transmission, especially in applications requiring a monolithic structure and low refractive index interfaces that cause total internal reflection, preventing certain light rays from passing through.
Innovation Solution
The development of light directing films with internal corrugated boundaries formed by layers of different refractive indices, allowing for smooth external surfaces and efficient light redirection through refraction and total internal reflection, enabling the films to be laminated onto optical waveguides without air gaps, thus enhancing light distribution and collimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If external surface microstructures (corrugations) are used for light directing, then light redirection function is achieved, but surface soiling increases and cleaning becomes complicated
Solution Approach 1:
The invention extracts the light directing function from the external surface to the internal boundary between layers. The corrugations are moved from the outer surface to the internal interface, allowing the external surface to remain smooth and resistant to soiling while maintaining the light redirection capability through the internal structured boundary.
Solution Approach 2:
The invention applies different structural qualities to different locations: the external surface is kept smooth and uniform for ease of cleaning, while the internal layer boundary is structured with corrugations to provide the light directing function. This local differentiation resolves the contradiction between soiling resistance and light redirection.
2Illumination intensity
If external surface corrugations are used, then light bending is achieved, but air pockets are created between layers reducing light transmission
Solution Approach 1:
The corrugated structure is extracted from the external surface and relocated to the internal layer boundary. This eliminates the formation of air pockets between external layers while maintaining the light bending function through the internal refractive index difference between layers.
Solution Approach 2:
The invention uses a composite multi-layer structure where each layer has a specific refractive index. The internal boundary between these composite layers provides the corrugation effect for light bending without introducing air pockets, as the layers are optically coupled through adhesive or direct contact.
3Illumination intensity
If corrugated surface is used for light directing, then light redirection is achieved, but surface cleaning becomes complicated
Solution Approach 1:
The light directing corrugations are taken out from the external surface and placed at the internal layer boundary. This allows the external surface to remain smooth and easy to clean, while the internal structured boundary continues to provide the necessary light redirection function.
Solution Approach 2:
Different surface qualities are applied locally: the external surface is smooth for ease of cleaning, while the internal boundary has corrugations for light directing. This local quality differentiation resolves the contradiction between cleaning ease and light redirection.
4Stability of the object's composition
If monolithic structure is desired, then air pockets are eliminated, but conventional corrugated films cannot provide smooth external surfaces
Solution Approach 1:
The corrugated structure is extracted from the external surface and relocated to the internal layer boundary. This enables the external surface to be smooth for monolithic appearance while the internal boundary maintains the structured light directing function without creating external air pockets.
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 provides improved light redirection and distribution within a film-thickness optical system, eliminating the limitations of conventional films by using internal boundaries to bend light, resulting in enhanced light bending capabilities and increased efficiency in applications like LCD backlights and signage.
Implementation Method 1
Light passes through at least one facet and is redirected from its original propagation path by means of refraction or total internal reflection (TIR)
Implementation Method 2
Light passes through at least one facet and is redirected from its original propagation path by means of refraction or total internal reflection (TIR)
Data Source
AI summary
Light directing film structure employing at least two layers having different refractive indices and forming a continuous corrugated boundary between major surfaces of the film. The corrugated boundary forms a plurality of alternating facets forming different dihedral angles with a prevalent plane of the film structure. The facets may longitudinally extend along an arcuate or circular path. Light received by a major surface of the film structure is internally redirected by interacting with the facets of the corrugated inter-layer boundary and may be emitted from the opposing major surface towards a new propagation direction which is different from the original propagation direction.