Light Guiding Member Concave-Convex Pattern for Luminance Uniformity
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Solution Overview
Problem
Existing light-emitting devices used as backlights in image display apparatuses face issues with uneven luminance and leakage light, where reducing groove portions to prevent luminance unevenness increases leakage light, and increasing groove portions to reduce leakage light exacerbates luminance unevenness.
Innovation Solution
A light-emitting device with a plate-shaped light guiding member featuring a concave-convex pattern on its light reflection/exit surface, where the convex portions are designed to reflect light inward, and a reflection member is used to direct light back into the light guiding member, optimizing the angle range of reflected light to improve luminance uniformity and reduce leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If groove portions are increased on the light guiding member surface, then leakage light to adjacent regions is reduced, but luminance uniformity deteriorates
Solution Approach 1:
The patent applies local quality by creating different surface structures in different regions of the light guiding member. Specifically, the exit surface has a first region with groove portions for light sources and a second region with a different structure (flat or different groove pattern) for light emission. This allows each region to have optimized properties: the first region controls leakage light while the second region ensures luminance uniformity.
Solution Approach 2:
The exit surface of the light guiding member is segmented into multiple regions with different structures. The first region contains groove portions corresponding to light source positions, while the second region has a different structure. This segmentation allows independent optimization of each region's function.
2Illumination intensity
If groove portions are decreased on the light guiding member surface, then luminance uniformity is improved, but leakage light to adjacent regions increases
Solution Approach 1:
Instead of uniformly reducing groove portions across the entire surface, the patent applies local quality by maintaining groove portions only in the first region where light sources are located, while the second region has a different structure. This localized approach prevents leakage light at the source while preserving luminance uniformity in the emission region.
3Ease of manufacture
If the light guiding member structure is simplified, then manufacturing ease is improved, but light control performance deteriorates
Solution Approach 1:
The patent segments the exit surface into two regions with different structures, which can be manufactured using different processes optimized for each region's requirements. This segmentation allows the use of simpler manufacturing for the second region while applying more complex structures only where necessary in the first region.
Solution Approach 2:
By applying complex groove structures only in the first region where light sources are located and using simpler structures in the second region, the patent achieves effective light control with minimized manufacturing complexity. The complex structure is localized only where it is most needed for preventing leakage light.
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 effectively reduces luminance unevenness and leakage light in adjacent regions by controlling the angle range of reflected light, enhancing the uniformity of luminance and minimizing light leakage in other areas.
Implementation Method 1
The light reflection/exit surface of the light guiding member has a concave-convex pattern including a plurality of convex portions which continuously formed in the first direction on the light reflection/exit surface of the light guiding member, extends in a second direction perpendicular to the thickness direction and the first direction, and reflects the light emitted from the light-emitting elements inward
Implementation Method 2
a reflection member which is disposed so as to face an opposite surface of the light reflection/exit surface of the light guiding member and which reflects the light reflected inward from the light reflection/exit surface and passing through the light guiding member and makes the light incident from the opposite surface to the light guiding member
Data Source
AI summary
A light-emitting device includes: a light guiding member; a plurality of light-emitting elements; and a reflection member. A light reflection/exit surface of the light guiding member has a concave-convex pattern including a plurality of convex portions reflecting light emitted from the light-emitting elements inward. On the assumption that L is a distance between the light-emitting elements, t is a thickness of the light guiding member, an incident angle φ of the light on the light reflection/exit surface is an angle between a line segment obtained by projecting a light path from the light-emitting element to the light reflection/exit surface and a line segment extending from a central point of the light-emitting element to the light reflection/exit surface, and θ is a maximum angle range of reflected light, a value of the angle range θ decreases as a value of the incident angle φ increases in a range of 0<φ<tan−1 (L/t).