Optical Structure With Periodic Micro-Structures For LED Uniformity
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Solution Overview
Problem
In backlight modules, increasing the spacing between LED light sources leads to uneven lighting due to the assumption of LEDs as point light sources, which is no longer valid when optical components are scaled down, necessitating a design that accounts for the different emitting portions of LEDs to achieve light uniformity.
Innovation Solution
An optical structure comprising a substrate with a light-emitting element, a cap covering the element, and periodically arranged micro-structures on the cap's top portion, which modify the light distribution by deflecting light rays, making the light source appear larger and maintaining uniformity even with increased spacing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the spacing between LED light sources is increased, then the device complexity is reduced and manufacturing is easier, but the lighting uniformity deteriorates
Solution Approach 1:
The cap surface is segmented into multiple micro-structures (prisms, cones, or gratings) that are periodically arranged. Each micro-structure acts as an independent light-modifying element, collectively achieving uniform light distribution across the entire surface even when LEDs are spaced farther apart.
Solution Approach 2:
The micro-structures are specifically positioned on the cap surface facing the light-emitting element to create localized light modification zones. This local optical processing ensures that light from each LED is redistributed in a controlled manner to fill gaps between adjacent LEDs, maintaining overall uniformity.
2Illumination intensity
If the beam angle of each LED is widened to achieve light uniformity, then the lighting coverage is improved, but the optical component size must be scaled down which makes LEDs no longer point light sources
Solution Approach 1:
Instead of trying to widen the LED beam angle directly, the invention introduces a new dimension of optical control through micro-structures on the cap surface. These micro-structures manipulate light in the spatial domain, creating effective beam widening without modifying the LED itself, thus avoiding the complexity of designing for extended LED emitting areas.
3Illumination intensity
If micro-structures are added to the cap to modify light distribution, then the lighting uniformity is improved, but the device complexity increases
Solution Approach 1:
The cap with micro-structures serves multiple functions simultaneously: it acts as a protective cover for the LED, a light-diffusing element, and a beam-shaping component. This multi-functionality reduces the need for separate optical components, thereby limiting the increase in overall device complexity despite adding micro-structures.
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 optical structure effectively widens the beam angle, ensuring light uniformity across the light-emitting surface, with a 50% intensity radius exceeding that of known structures, suitable for LED backlight applications with a pitch ratio of 1:3 to 1:2.5.
Implementation Method 1
the first micro-structure is disposed on a first side of the top portion facing the light-emitting element... which modify the light distribution by deflecting light rays
Data Source
AI summary
An optical structure is provided. The optical structure includes a substrate and a light-emitting element disposed on the substrate. The optical structure also includes a cap disposed on the substrate and covering the light-emitting element. The cap has a top portion and a sidewall connected to the top portion. The optical structure further includes a first micro-structure disposed on a first side of the top portion facing the light-emitting element. The first micro-structure is periodically arranged.