Vehicle Headlamp Reflector Geometry for Uniform Illuminance
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Solution Overview
Problem
Existing vehicle headlamps with semiconductor light emitting elements experience non-uniform illuminance and the generation of lines of light in their light distribution patterns due to the arrangement of these elements, which affects the quality of the light distribution.
Innovation Solution
The vehicle headlamp design includes a configuration where the lateral distance between adjacent semiconductor light emitting elements is greater than the length of each element, with each element positioned on separate substrates and a base plate, and the reflectors are inclined at specific angles to optimize light distribution, ensuring uniformity and preventing lines of light by adjusting the inclination angles of the reflectors and positioning the light emitting module behind the focal plane of a projector lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If semiconductor light emitting elements are arranged at predetermined intervals to form a light distribution pattern, then the light distribution pattern can be formed with desired size and shape, but illuminance of boundary portions between distributions of light from each element is decreased and non-uniformity occurs
Solution Approach 1:
The patent applies local quality by providing minute reflectors with different shapes for different semiconductor light emitting elements. Specifically, reflectors for elements at boundary positions have different shapes compared to reflectors for elements at central positions, allowing targeted control of light distribution in boundary regions to improve illuminance uniformity across the entire light distribution pattern.
Solution Approach 2:
The patent changes the shape parameter of reflectors based on the position of semiconductor light emitting elements. By varying the reflector shape (a key geometric parameter) according to whether an element is located at a boundary or central position, the light distribution characteristics are optimized to eliminate non-uniformity in boundary portions while maintaining overall pattern integrity.
2Ease of operation
If minute reflectors are provided for each semiconductor light emitting element to control irradiation direction, then light distribution can be optimized, but the generation of lines of light is not completely prevented
Solution Approach 1:
The patent provides minute reflectors with position-dependent shapes to achieve localized control of light irradiation. Elements at boundary positions receive reflectors with shapes optimized to suppress line formation, while central elements receive different reflector shapes, creating a differentiated control strategy that effectively prevents lines of light throughout the light distribution pattern.
Solution Approach 2:
The patent introduces asymmetry by using different reflector shapes for boundary elements versus central elements. This asymmetric approach recognizes that boundary elements generate lines of light differently than central elements, and applies tailored reflector geometries to each category, thereby eliminating the harmful effect of lines of light while maintaining precise irradiation control.
3Object-generated harmful factors
If the light emitting module is placed behind the focal plane of the projector lens, then some line generation is reduced, but lines of light still occur and uniformity is not fully achieved
Solution Approach 1:
The patent combines the focal plane placement with position-dependent reflector shapes. While placing the light emitting module behind the focal plane provides some reduction in line generation, the additional local quality control through differentiated reflector shapes for boundary and central elements further enhances uniformity and completely prevents lines of light in the light distribution pattern.
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 enhances the uniformity of light distribution, reduces the occurrence of lines of light, and allows for a more flexible design with reduced manufacturing costs by optimizing the placement and spacing of semiconductor light emitting elements.
Implementation Method 1
a plurality of reflectors (22) arranged in parallel with each other in the lateral direction and corresponding respectively to the plurality of semiconductor light emitting elements (18), wherein each of the plurality of reflectors (22) has a different shape according to a position of a corresponding one of the plurality of semiconductor light emitting elements (18)
Data Source
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AI summary
A vehicle headlamp (1) includes: a light emitting module (15) including: a plurality of semiconductor light emitting elements (18) each configured to emit light and disposed to be separated from each other in a lateral direction of the vehicle headlamp; a plurality of reflectors (22) each provided for a corresponding one of the semiconductor elements to reflect light emitted from the corresponding semiconductor light emitting element, wherein one of the reflectors located at a center position in the lateral direction is defined as a central reflector (22A); and a projector lens (29) configured to project the light emitted from the light emitting module forward, wherein the light emitting module is disposed behind a focal plane of the projector lens. Each of the reflectors (22) other than the central reflector (22A) has an outer side (26) and an inner side (25) facing the outer side, wherein a distance between the inner side and the central reflector is smaller than a distance between the outer side and the central reflector in the lateral direction. In at least one of the reflectors (22), a first inclination angle (θo) of the outer side (26) with respect to an optical axis is smaller than a second inclination angle (θi) of the inner side (25) with respect to the optical axis.