Light-Transmissive Member Layout for Sharp Headlight Cut-Off
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Solution Overview
Problem
Existing light-emitting devices for vehicle headlights face challenges in providing a clear cut-off line in low beam mode while maintaining a compact optical system, as the large wavelength conversion member increases the light-emitting surface area, making it difficult to achieve both high luminance and a clear boundary between the light-emitting surface and the covering member.
Innovation Solution
A light-emitting device with a rectangular light-emitting surface and a plate-shaped light-transmissive member is designed, where the light-transmissive member is positioned such that one side is outside and the other side is inside the light-emitting element's surface, creating a sharp luminance difference across the boundary, allowing for a clear cut-off line with a simple and small optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a large wavelength conversion member is disposed on light-emitting elements such that its periphery is located outside the peripheries of the light-emitting surfaces, then a clear boundary between light-emitting surface and covering member is achieved, but the light-emitting surface area becomes large making the optical system structure large
Solution Approach 1:
The invention divides the wavelength conversion member into multiple separate wavelength conversion members, each disposed on individual light-emitting elements. This segmentation allows the overall light-emitting surface area to be reduced while maintaining clear boundaries, as each small wavelength conversion member only needs to cover its corresponding light-emitting element rather than requiring one large wavelength conversion member extending beyond all light-emitting surfaces.
2Reliability
If a clear cut-off line is provided in low beam mode, then safety is enhanced by preventing dazzling of oncoming drivers, but the optical system becomes more complex
Solution Approach 1:
The invention applies different properties to different parts of the optical system by using wavelength conversion members with specific optical characteristics at the boundaries. The wavelength conversion members convert light wavelengths and create localized luminance differences at the boundaries, which naturally forms clear cut-off lines in low beam mode without requiring additional complex optical components.
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 configuration enables a clear cut-off line in low beam mode while minimizing the light-emitting surface area, resulting in a compact optical system that enhances safety and efficiency for vehicle headlights.
Implementation Method 1
a plate-shaped light-transmissive member having a lower surface that faces the upper surface of the at least one light-emitting element
Data Source
AI summary
A light-emitting device includes a substrate; at least one light-emitting element on or above the substrate; a plate-shaped light-transmissive member having a lower surface that faces an upper surface of the at least one light-emitting element; a covering member that covers a lateral surface of the at least one light-emitting element and a lateral surface of the light-transmissive member; and a light-guiding member that is disposed between the light-emitting element and the light-transmissive member. In a plan view, a first lateral side of an upper surface of the light-transmissive member is outside a first lateral side of the upper surface of the at least one light-emitting element, and a second lateral side of the upper surface of the light-transmissive member is inside a second lateral side of the upper surface of the at least one light-emitting element.