Optical Element Cavity Design for Wide Light Distribution
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Solution Overview
Problem
LED illumination apparatuses struggle to achieve a wide light distribution similar to incandescent bulbs, as light beams returning to the LED are largely absorbed, reducing light output due to the use of optical elements with scattering members.
Innovation Solution
An optical element with a rotating, symmetrical design featuring a cylindrical light guide and hemispherical scattering portion, where the inner surface of the cavity is partially a diffusing surface and partially a mirror surface, minimizing light absorption by scattering light beams away from the LED.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an optical element with a scattering member is used to increase the light distribution angle, then the light distribution angle is improved, but the light output ratio deteriorates due to light beams returning to and being absorbed by the LED
Solution Approach 1:
The patent converts the harmful effect of light beams returning to the LED (which causes absorption and energy loss) into a beneficial effect by introducing a reflective surface that redirects these returning light beams toward the scattering member. This transforms the previously wasted light into useful illumination, simultaneously improving light distribution while maintaining high light output ratio.
Solution Approach 2:
The patent introduces a reflective surface as an intermediary element between the LED and the scattering member. This intermediary captures light beams that would otherwise return to and be absorbed by the LED, and redirects them toward the scattering member for wide-angle distribution. The reflective surface acts as a mediator that prevents energy loss while achieving the desired light distribution effect.
2Illumination intensity
If a wide light distribution lens is used to achieve a wide distribution angle like an incandescent bulb, then the light distribution is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple optical functions into a single integrated optical element. The light guide rod, scattering member, and reflective surface are combined into one unified structure, eliminating the need for separate wide light distribution lenses and reducing overall device complexity while achieving the same wide-angle light distribution effect.
Solution Approach 2:
The optical element is designed to perform multiple functions simultaneously: guiding light from the LED, scattering light for wide distribution, and reflecting returning light beams back toward the scattering member. This multi-functional design replaces what would traditionally require multiple separate optical components, simplifying the overall device structure.
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 element efficiently achieves a wide light distribution angle of approximately 310°, reducing light loss and enhancing the light output ratio, similar to incandescent bulbs.
Implementation Method 1
A light beam emitted from the LED propagates by total reflection in the light guide rod to be guided to the scattering member
Implementation Method 2
Each light beam reaching the scattering member is scattered by the scattering member to emerge to the outside of the optical element
Implementation Method 3
the inner surface of the cavity is partially a diffusing surface and partially a mirror surface, minimizing light absorption by scattering light beams away from the LED
Data Source
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AI summary
An optical element according to an embodiment is formed from a material transparent to visible light and has a rotationally symmetrical shape with respect to the central axis. A cavity containing no transparent material is provided inside the optical element. The inner surface of the cavity has a shape in which a boundary line of the cavity along which a plane including the central axis intersects the inner surface includes a curve portion expanding toward the outside of the optical element. In addition, when an origin is set in the cavity, a clockwise direction around the origin along the boundary line is set as a positive direction, a first tangent vector is set at a first point on the boundary line, and a second tangent vector is set at a second point adjacent to the first point in the positive direction, an angle defined by the second tangent vector with respect to the first tangent vector with the clockwise direction being a positive direction is not less than 0°. The inner surface of the cavity does not include any surface recessed inwardly.