Vertically Stacked LED Light Source for Automotive Lighting
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Solution Overview
Problem
Semiconductor light sources, such as LEDs, face a challenge in achieving high luminance while maintaining miniaturization, as reducing their size decreases the generated light flux, and existing methods to increase luminance through small apertures are limited in space efficiency.
Innovation Solution
The solution involves vertically stacking and partially overlapping LED light sources with non-aligned light output sections, allowing for a reduction in the overall footprint size by utilizing non-light-outputting areas for space savings, and incorporating optical enhancement materials and structures to maintain luminance and etendue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the size of semiconductor light source is reduced for miniaturization, then the footprint area is reduced, but the generated light flux decreases
Solution Approach 1:
The patent transitions from horizontal arrangement to vertical stacking of multiple LED light sources. By utilizing the vertical dimension (z-axis), multiple LEDs can be arranged in a compact footprint while each LED maintains its full light-generating area. The light output sections are positioned at different vertical levels and laterally offset, allowing light from each LED to exit without obstruction, thereby maintaining high light flux output while achieving miniaturization of the overall device footprint.
2Illumination intensity
If a small aperture is used to increase luminance, then the luminance is improved, but the space efficiency is limited
Solution Approach 1:
The patent divides the light output function across multiple segmented LED sources arranged vertically. Instead of using a single small aperture to concentrate light, multiple LED light sources with their own light output sections are distributed in the vertical direction. Each LED maintains its own light-generating area and light output section, allowing each to contribute to the total luminance without requiring restrictive apertures. This segmentation enables high luminance through additive contribution of multiple sources rather than spatial concentration of a single source.
3Area of stationary object
If multiple LED light sources are vertically stacked with overlapping areas, then the footprint is reduced, but the light output sections may interfere with each other
Solution Approach 1:
The patent employs asymmetric positioning of light output sections relative to the vertical stacking arrangement. The light output sections of vertically stacked LEDs are laterally offset from one another, creating an asymmetric configuration. This asymmetric arrangement ensures that the light output path of each LED does not intersect with or obstruct the light output sections of other LEDs in the vertical stack. The asymmetric positioning allows maximum vertical integration while maintaining unobstructed light output from each source, resolving the potential interference issue.
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
This approach enables the creation of high-luminance light sources with reduced size, achieving equivalent or greater light output while minimizing footprint, suitable for applications like automotive lighting and projection systems.
Implementation Method 1
a semiconductor diode structure adapted to generate light
Implementation Method 2
a light output section above the semiconductor diode structure adapted to output light from the semiconductor diode structure
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Proposed is a light source comprising first and second LED light sources. Each of the first and second LED light sources have: a semiconductor diode structure adapted to generate light; and a light output section above the semiconductor diode structure adapted to output light from the semiconductor diode structure in a light output direction, the area of the light output section being less than the area of the semiconductor diode structure. The second LED light source is arranged above and at least partially overlapping the first LED light source with non-aligned light output sections with respect to the light output direction.