Vehicle Lighting Unit with Elliptic-Conical Reflectors for Thin Profile
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Solution Overview
Problem
Conventional vehicle headlight units with LED light sources face challenges in achieving a thin profile in the depth direction while maintaining high light utilization efficiency, as reducing the dimension of the first reflecting surface compromises light coverage and results in decreased light intensity and visibility.
Innovation Solution
The vehicle lighting unit incorporates an LED light source with a projection lens and an optical member featuring a first reflecting surface with an elliptic edge and a second reflecting surface with a conical curvature, allowing direct light to pass through the lens to form a light distribution pattern with a cut-off line, while the first and second reflecting surfaces are shortened in the depth dimension to achieve a thinner profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the dimension of the first reflecting surface is decreased to achieve a thinner profile, then the depth dimension is reduced, but the light utilization efficiency deteriorates and light intensity decreases
Solution Approach 1:
The patent changes the arrangement dimension of the reflecting surfaces from the optical axis direction (depth) to the horizontal direction (width). The first and second reflecting surfaces are disposed horizontally adjacent to each other rather than being stacked in the depth direction, allowing the light path to be extended horizontally while keeping the depth dimension small, thus resolving the contradiction between thin profile and light utilization efficiency
Solution Approach 2:
The patent employs curved reflecting surfaces (first reflecting surface and second reflecting surface) instead of flat surfaces. The curved surfaces are designed to reflect light from the LED light source effectively, with the first reflecting surface having a curvature that directs light through the projection lens and the second reflecting surface capturing and redirecting light that would otherwise be lost, thereby maintaining high light utilization efficiency in a compact depth configuration
2Length of stationary object
If the dimension of the first reflecting surface is decreased to achieve a thinner profile, then the depth dimension is reduced, but the far visibility and light/dark border clarity deteriorate
Solution Approach 1:
By extending the light path horizontally rather than vertically in depth, the patent maintains sufficient optical path length for forming clear light distribution patterns with distinct cut-off lines, while keeping the depth dimension small. The horizontal arrangement of reflecting surfaces allows adequate space for light to be directed and shaped properly
Solution Approach 2:
The patent introduces a projection lens as an intermediary optical element that works in conjunction with the horizontally arranged reflecting surfaces. The projection lens receives light from the LED source and the reflecting surfaces, and projects it to form a controlled light distribution pattern with clear light/dark borders, thereby maintaining far visibility and pattern clarity in a compact depth configuration
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 maintains high light utilization efficiency and allows for a thinner profile in the depth direction, ensuring clear light/dark borders and improved far visibility by utilizing direct light from the LED source effectively.
Implementation Method 1
a first reflecting surface horizontally disposed below the optical axis of the LED light source and substantially on the optical axis of the vehicle lighting unit
Implementation Method 2
a second reflecting surface disposed above the optical axis and facing to the first reflecting surface
Implementation Method 3
a projection lens disposed forward in a direction of the optical axis of the LED light source and having an optical axis substantially parallel with the optical axis of the LED light source
Data Source
AI summary
A vehicle lighting unit can include a first reflector surface and a second reflector surface disposed vertically with the optical axis of an LED light source interposed therebetween. The first reflecting surface and the second reflecting surface can form respective light distribution patterns. The first reflecting surface can include an edge near the projection lens formed in a substantially elliptic shape and designed so as to take an aberration of the projection lens into consideration. The edge can be disposed so as to coincide with a focus group of the projection lens. The second reflecting surface can be formed to have a substantially conical curved surface or a curved surface having at least a part of a cross section of a substantially conical curved surface. Direct light emitted from the LED light source and passing through/between the first reflecting surface and the second reflecting surface can form a light distribution pattern.