LED Phosphor Package Layout for Sharp Headlight Cutoff
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Solution Overview
Problem
Existing light emitting devices for automotive headlights face challenges in achieving a small size while maintaining sharp cutoff performance, as the disposition of light shielding members between lateral surfaces and the outer frame complicates size reduction.
Innovation Solution
A light emitting device design featuring a substrate with light emitting elements, a phosphor member, a cover member, and a light shielding member, where the light shielding member is disposed on the cover member along the perimeter of the phosphor member, and the device is manufactured by arranging light emitting elements in rows with specific intervals and using a frame member to form recesses for the light shielding members, allowing for smaller size and sharp cutoff performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a light shielding member is disposed between the lateral surfaces of the transparent member and the outer frame, then sharp cutoff performance is improved, but device size increases
Solution Approach 1:
The light shielding member is merged with the cover member by forming an integrated structure where the light shielding member protrudes from the cover member toward the phosphor member. This integration eliminates the need for separate light shielding components and reduces overall device size while maintaining the light shielding function for sharp cutoff performance
Solution Approach 2:
The light shielding function is achieved by extending the light shielding member in the vertical dimension from the cover member, rather than requiring additional horizontal space between the transparent member and outer frame. This dimensional transition allows sharp cutoff performance without increasing device footprint
2Volume of moving object
If the device size is reduced, then compactness is improved, but sharp cutoff performance deteriorates
Solution Approach 1:
The light shielding member is positioned locally at the perimeter of the phosphor member where light leakage occurs, rather than requiring a complete light shielding structure throughout the entire device. This localized approach maintains sharp cutoff performance while minimizing the overall device size
Solution Approach 2:
The light shielding member acts as an intermediary element between the phosphor member and the cover member, blocking stray light at the critical interface where light leakage occurs. This intermediary structure achieves sharp cutoff performance without requiring a large device envelope
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 design enables a compact light emitting device capable of achieving a sharp cutoff line with a simple optical system, reducing light leakage and increasing luminance difference, thus suitable for automotive headlight applications.
Implementation Method 1
disposing a phosphor member on each light emission surface of the plurality (n × m pieces) of light emitting elements
Implementation Method 2
disposing a light shielding member in each of the recesses; having an absorption coefficient larger than that of the first covering member with respect to visible light
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~4G
AI summary
A light emitting device manufacturing method includes: disposing n pieces of light emitting elements in m rows on a substrate block, where an interval between a kth light emitting element from one end of rows and a (k+1)th light emitting element has a first distance; disposing a phosphor member on the light emitting elements; disposing a frame member to surround the light emitting elements; disposing a cover member in each area surrounded by the frame member to cover lateral surfaces of the light emitting elements and the phosphor members while forming recesses at an upper surface between the kth light emitting elements and the (k+1)th light emitting elements apart by the first distance; disposing a light shielding member in each recess; and cutting the light shielding members, the cover members, and the substrate block between the light emitting elements that are apart by the first distance.