Planar Illumination Reflector Layout for Irregular Shape Uniformity
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Solution Overview
Problem
In direct-type planar illumination devices with a linear Fresnel lens, luminance unevenness occurs in irregularly shaped areas due to the difficulty in linearly arranging light sources along the light condensing position, leading to dark areas and degraded luminance uniformity.
Innovation Solution
A planar illumination device with a reflector having extended reflective surfaces and a prism of the linear Fresnel lens, which are adjusted to accommodate irregular shapes, ensuring light sources are arranged efficiently and maintaining luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If light sources are linearly arranged along the light condensing position of the linear Fresnel lens, then light distribution efficiency is improved, but luminance uniformity deteriorates in irregular shape areas due to dark areas
Solution Approach 1:
The reflector is designed with different structural characteristics in different regions: in the irregular shape area, the reflector includes an extended reflective surface that extends in a direction orthogonal to the light source arrangement direction, while in the regular shape area, the reflector has conventional reflective surfaces. This local differentiation allows the irregular shape area to receive adequate light reflection, eliminating dark areas and improving luminance uniformity while maintaining the overall light distribution efficiency.
2Adaptability or versatility
If the planar shape of the light emitting area is made irregular, then adaptability to different display shapes is improved, but dark areas occur due to difficulty in arranging light sources along the light condensing position
Solution Approach 1:
The reflector is designed with asymmetric reflective surfaces that adapt to the irregular shape of the light emitting area. Specifically, in the irregular shape area, the reflector includes an extended reflective surface that extends in a direction orthogonal to the light source arrangement direction, creating an asymmetric structure that compensates for the irregular planar shape and ensures uniform light distribution.
3Ease of manufacture
If the reflector has conventional reflective surfaces for regular shapes, then manufacturing simplicity is maintained, but luminance uniformity deteriorates in irregular shape areas
Solution Approach 1:
The reflector is divided into different functional segments: a conventional reflective surface portion for regular shape areas and an extended reflective surface portion for irregular shape areas. This segmentation allows the reflector to maintain manufacturing simplicity in regular areas while addressing the luminance uniformity issue in irregular areas through the added extended portion.
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
Prevents dark areas and enhances luminance uniformity by allowing light to reach the entire emitting area, even in non-rectangular shapes, while maintaining the light-condensing function.
Implementation Method 1
a reflector having a plurality of reflective surfaces forming respective segments, each segment surrounding a corresponding one of the plurality of light sources
Implementation Method 2
A direct-type planar illumination device having a linear Fresnel lens has been proposed
Implementation Method 3
light sources such as Light Emitting Diodes (LEDs) need to be linearly arranged along the light condensing position (focal point) of the linear Fresnel lens
Data Source
AI summary
A planar illuminating device of an embodiment is a directly-under type planar illuminating device provided with a linear Fresnel lens, and comprises a plurality of light sources, and a reflector. The plurality of light sources are disposed in a linear fashion on a board, along condensing positions of the Fresnel lens. The reflector includes reflecting surfaces constituting segments surrounding each of the light sources. In a part in which the light sources cannot be disposed along the condensing position because a planar shape of a light emitting area of the planar illuminating device is an irregular shape that is not rectangular, the segment of the reflector adjacent to said part is expanded to an outer edge side of the planar illuminating device.