Projection Lens Optical Surface Determination Method
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Solution Overview
Problem
In vehicular headlamps with a light-passing member that internally reflects light twice, determining a unique rear face is challenging due to the complexity of incoming and outgoing wavefronts, making it difficult to achieve a predetermined light distribution pattern.
Innovation Solution
An optical surface determination method for a projection lens that sets incoming and outgoing wavefronts, calculates intermediate wavefronts based on reflection and refraction regions, and determines the shape of the rear face to ensure non-intersecting light rays, allowing for easy determination of the optical surface forming a predetermined light distribution pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a light-passing member internally reflects light twice to achieve a predetermined light distribution pattern, then the light distribution control is improved, but the determination of the rear face optical surface becomes complex and non-unique
Solution Approach 1:
The optical path is segmented into distinct regions: a first reflection region on the front face, a second reflection region on the rear face, and a refraction region on the front face. This segmentation allows each region to be designed and determined independently, simplifying the overall optical surface determination process while achieving the desired light distribution pattern through coordinated action of these segmented regions.
Solution Approach 2:
The method performs preliminary determination of the first intermediate wavefront after the first reflection and the second intermediate wavefront before refraction. By calculating these intermediate wavefronts in advance based on the light source characteristics and optical surface shapes, the rear face optical surface can be uniquely determined without complex iterative processes.
2Reliability
If the rear face shape is determined to ensure non-intersecting light rays, then the optical performance is improved, but the design complexity increases
Solution Approach 1:
The patent replaces complex mechanical trial-and-error design methods with mathematical wavefront calculations. By using wavefront optics theory to calculate the first and second intermediate wavefronts and determine the rear face shape that ensures non-intersecting light rays, the design process becomes more systematic and reliable while reducing overall complexity.
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 method simplifies the design of the optical surface, ensuring efficient light distribution and reducing glare by accurately determining the optical surface of the projection lens, thereby enhancing the vehicular headlamp's performance.
Implementation Method 1
light entering from the rear face is internally reflected twice and then emitted from the front face
Implementation Method 2
emits the light from the front face... calculating a second intermediate wavefront before refracted by a refraction region of the front face
Data Source
Figure 1A~1B
Figure 2~3
Figure 4A~4C
AI summary
A projection lens includes a rear face (14b) through which light emitted from a light source (12) enters, and a front face (14a) from which the light is emitted in front of a vehicle in a predetermined light distribution pattern. The projection lens (14) is configured such that, upon entering the projection lens (14), an incoming wavefront emitted from the light source (12) is internally reflected by a first reflection region (14a1) of the front face (14a), a first intermediate wavefront generated by the internal reflection by the first reflection region (14a1) is internally reflected by a second reflection region (14b1) of the rear face (14b), a second intermediate wavefront generated by the internal reflection by the second reflection region (14b1) is refracted by a refraction region (14a1) of the front face (14a), and the refracted wavefront is emitted as an outgoing wavefront. The second reflection region (14b1) is an optical surface determined based on the first intermediate wavefront and the second intermediate wavefront.