Planar Light Emitting Element with Segmented Reflective Plates for High Directivity
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Solution Overview
Problem
Conventional planar light source devices fail to achieve sufficient directivity and collimation for effective use with light emitting elements like lens arrays, leading to conflicts between viewing angle and luminance level, with existing solutions not adequately addressing the need for high directivity in all directions.
Innovation Solution
A planar light emitting element is designed with first and second refractive index layers and a reflective plate, where the refractive indexes are carefully selected to ensure high directivity, and a prism sheet or depolarized light transmission layer is used to enhance light output, allowing for collimated or spread light at a small angle in specific directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional planar light source devices are used, then light output is achieved, but directivity and collimation are insufficient
Solution Approach 1:
The light guide body is divided into multiple light output sections, each with dedicated reflective plates positioned at specific locations. This segmentation allows different regions to control light in specific directions, achieving high directivity while maintaining overall viewing angle through the distributed arrangement of these segments.
Solution Approach 2:
Reflective plates are selectively positioned at specific locations corresponding to different light output sections, with each plate having a specific orientation angle. This local quality variation enables different regions to provide light with different directivity characteristics, resolving the contradiction between high directivity and wide viewing angle.
2Illumination intensity
If light focusing elements are used, then light concentration is improved, but luminance level conflicts with viewing angle
Solution Approach 1:
Different reflective plates are positioned at different orientations corresponding to different light output sections. This creates local quality variations where each section provides optimized light distribution, allowing light focusing elements to achieve high luminance in specific directions while maintaining adaptability for different viewing angles through the distributed light output sections.
Solution Approach 2:
The invention transitions from conventional single-direction light control to multi-directional control by positioning reflective plates at different orientations in different light output sections. This dimensional approach allows simultaneous achievement of high luminance level through focusing and wide viewing angle through distributed directional control.
3Illumination intensity
If reflective plates are positioned to increase directivity, then light control is improved, but device complexity increases
Solution Approach 1:
The light guide body is segmented into multiple light output sections with reflective plates positioned at specific locations. This segmentation strategy achieves high directivity through localized control while managing device complexity by organizing the structure into modular, repeatable units that can be systematically arranged.
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 enables the planar light emitting element to output light with high directivity, improving the functionality of light focusing elements and maintaining constant luminance levels across the light output surface, while allowing for increased viewing angles and luminance levels.
Implementation Method 1
a reflective plate adapted to reflect light output from the light guide body through the opening section provided in the second refractive index layer
Implementation Method 2
When refractive indexes of the light guide body, the first and second refractive index layers are n1, n2 and n3, respectively, the following expressions are established: n1>n2>n3
Data Source
AI summary
A planar light emitting element is capable of outputting light having high directivity in at least one direction. The planar light emitting element has a light guide plate and first and second low refractive index layers. Light incident on the light guide plate is totally reflected on the interface between the light guide plate and the second low refractive index layer, propagates in the light guide plate, and is output from the light guide plate to the first low refractive index layer through a light output opening section. When a refractive index of the first low refractive index layer is sufficiently smaller than a refractive index of the light guide plate, the light propagates in the light guide plate at a large angle with respect to a light output surface of the light guide plate. When the difference between the refractive indexes of the first and second low refractive index layers is small, a spreading angle of light output to the first low refractive index layer is small. The light having high directivity is reflected on a reflective mirror and output from the planar light emitting element.