Aspheric Imaging Lens for Vehicle Headlamp Homogeneous Illumination
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Solution Overview
Problem
Existing vehicle headlamps using LED modules face challenges in achieving homogeneous illumination in the far field due to gaps between LEDs, which results in inhomogeneous light intensity distribution, and require additional optical elements like scattering surfaces for correction, complicating manufacturing and installation.
Innovation Solution
An imaging lens with aspheric surfaces defined by a combination of conic sections and correction polynomials, which projects light with a controlled blur angle to the far field, blending LED gaps and achieving homogeneous illumination without the need for additional scattering surfaces, while maintaining manufacturing ease and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a scattering surface is added to correct light inhomogeneity, then illumination homogeneity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the imaging function and the homogenization function into a single optical element. The aspheric lens integrates light gathering, focusing, and uniform distribution capabilities, eliminating the need for separate scattering surfaces or additional optical components that would otherwise be required to achieve homogeneous illumination.
Solution Approach 2:
The aspheric lens serves multiple functions simultaneously: it acts as an imaging lens to focus light while also functioning as a homogenization element to eliminate LED gap effects. This multi-functional design replaces what would traditionally require multiple specialized optical components, reducing overall system complexity.
2Illumination intensity
If a scattering surface is applied to the lens surface, then light intensity distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs an aspheric surface design where the curvature is defined by a mathematical function (conic section plus deformation parameters). This continuous curved surface is manufactured as an integral part of the lens molding process, eliminating the need for separate scattering surface applications or post-processing steps that would complicate manufacturing.
Solution Approach 2:
The patent modifies the standard spherical surface parameters by introducing deformation parameters (a1, a2, a3, a4) to the conic section equation. This parameter-based design allows the complex aspheric shape to be defined mathematically and manufactured using standard precision molding techniques, maintaining ease of manufacture while achieving superior optical performance.
3Illumination intensity
If the imaging system is defocused to blur the image, then light inhomogeneity is reduced, but image quality deteriorates
Solution Approach 1:
The aspheric surface design enables the lens to control light ray paths precisely, achieving a balance between focusing and homogenization. The specific curvature profile allows the system to maintain sharp imaging while simultaneously reducing the visibility of LED gaps, avoiding the need for deliberate defocusing that would degrade image quality.
Solution Approach 2:
The aspheric lens creates different optical zones with varying properties: the central region maintains strong focusing capability for image quality, while peripheral regions are designed to spread light more uniformly to reduce LED gap effects. This local differentiation of optical properties allows simultaneous achievement of sharp imaging and homogeneous illumination.
4Illumination intensity
If additional optical elements are added to correct LED gaps, then illumination homogeneity is improved, but installation complexity increases
Solution Approach 1:
The patent merges multiple optical functions (imaging, focusing, homogenization) into a single integrated aspheric lens element. This eliminates the need to install and align multiple separate optical components, significantly simplifying the installation process while maintaining superior illumination homogeneity.
Solution Approach 2:
The aspheric lens serves as a universal optical element that performs multiple correction functions simultaneously. It addresses LED gap effects, controls light distribution, and maintains image quality all through a single component, eliminating the need for complex multi-element assemblies and their associated alignment procedures.
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 solution provides improved illumination homogeneity, reduced installation complexity, and lower manufacturing costs by defining a well-controlled blur angle that eliminates LED gaps in the far field, resulting in a smooth and homogeneous light intensity distribution.
Implementation Method 1
the light entry and exit surfaces are configured and arranged such as to project light entering the light entry surface and exiting the light exit surface with a controlled blur angle to a far field
Implementation Method 2
the curvature of which is defined by an overlay of a conic section plus at least one correction polynomial... in order to generate a predefined light intensity distribution in the far field
Data Source
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AI summary
The invention describes an imaging lens (1) for use in a light module (20) for a vehicle headlamp (30), comprising a light entry surface (2) and a light exit surface (3), the light entry and exit surfaces (2, 3) being configured and arranged to project light entering the light entry surface (2) and exiting the light exit surface (3) to a far field (4) in order to generate a predefined light intensity distribution (I) in the far field (4), wherein one or more of the light entry surface (2) and the light exit surface (3) comprise an aspheric surface (3) which curvature is defined by an overlay of a conic section plus at least one correction polynomial (C(r), C(x, y)) of at least second order or higher, wherein the correction polynomial (C(r), C(x, y)) describes a waveform. The invention further describes a light module (20) for a vehicle headlamp (30) comprising at least one such imaging lens (1). The invention yet further describes a vehicle headlamp (30) comprising such a light module (20).