Planar Illumination Light Guide Plate with Extended Portions for Corner Luminance
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Solution Overview
Problem
Planar illumination apparatuses with cutout corners and curved surfaces often experience uneven luminance due to gaps between LEDs and the curved surfaces, leading to inefficient light distribution and luminance issues.
Innovation Solution
A planar illumination apparatus with linearly disposed LEDs facing a flat lateral surface of a light guide plate, where extended portions on the light guide plate are spaced away from both ends, ensuring consistent light emission and minimizing gaps, thus enhancing luminous efficiency and preventing uneven luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the cutout portion has a curved surface and LEDs are disposed to face the curved surfaces, then the design property is improved, but gaps are produced between the LED and the curved surface resulting in uneven luminance
Solution Approach 1:
Instead of making the light guide plate surface curved to match the LED arrangement, the patent inverts the approach by keeping the light guide plate surface flat and arranging the LEDs to face the flat surface. This eliminates the gap formation issue while maintaining design flexibility through extended portions that can be shaped as needed.
Solution Approach 2:
The patent applies different surface characteristics to different regions: the main light incident surface is kept flat for optimal LED coupling, while extended portions at the corners can have different geometries. This local differentiation allows the LEDs to maintain consistent spacing and orientation relative to the flat surface, ensuring uniform luminance while still achieving desired corner illumination.
2Shape
If cutout portions are made at the corners of the light guide plate, then the design property is improved, but light emission to the corners becomes unreliable
Solution Approach 1:
The patent segments the light guide plate into a main body with cutout corners and extended portions that protrude toward the corners. This segmentation allows the main body to maintain its structural integrity and light guiding function, while the extended portions specifically address the corner illumination need by bringing the light incident surface closer to the corners.
Solution Approach 2:
The extended portions are designed in advance to protrude toward the corners before light emission occurs. This preliminary structural arrangement ensures that when LEDs are disposed on the light incident surface, their light can reach the corners of the light emitting region without requiring complex real-time adjustments or additional optical elements.
3Illumination intensity
If extended portions are added to the light guide plate, then light distribution to corners is improved, but the device complexity increases
Solution Approach 1:
The patent merges the corner extension function directly into the light guide plate structure itself, rather than adding separate components. The extended portions are integrated as part of the light guide plate's geometry, allowing them to perform both structural and optical functions simultaneously, thus improving corner light distribution without proportionally increasing device complexity.
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 ensures reliable light emission to the corners of the light emitting region, improving luminous efficiency and preventing uneven luminance by maintaining consistent light distribution across the illumination area.
Implementation Method 1
a light guide plate that has a lateral surface on which the light sources are disposed so as to face the lateral surface
Data Source
AI summary
A planar illumination apparatus includes: a plurality of light sources that are disposed linearly and that emit light; and a light guide plate that has a lateral surface on which the light sources are disposed so as to face the lateral surface and includes extended portions each extending in directions in which the extended portions are spaced away from each other from both ends of the lateral surface and are away from the light sources. The light guide plate has a light emitting region that is either in contact with a boundary or disposed on a side opposite to one of the extended portions with respect to the boundary, in which the boundary is established between an emission range of an end portion light source on a side adjacent to the extended portion and a region different from the emission range.