Optical Module Field Flattener for Adaptive Driving Beam
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Motor-vehicle optical modules with adaptive driving beams suffer from Petzval field curvature, leading to blurry projections of secondary elementary light sources due to a concave object focal surface, making it difficult to manufacture and limiting material choices for primary optical elements.
Innovation Solution
A field-correcting optical element, such as a single field flattener lens, is interposed between the emission plane and the projecting lens to correct the curvature, ensuring all light sources are clearly imaged and allowing for identical length light guides, facilitating easier manufacturing and use of materials like polycarbonate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the exit faces of the light guides are arranged on a curved surface to match the Petzval field curvature of the projecting lens, then the projection sharpness of secondary elementary light sources is improved, but the manufacturing complexity of the primary optical element increases due to variable light guide lengths
Solution Approach 1:
A field-correcting optical element (field flattener) is introduced as an intermediary component between the light guides and the projecting lens. This field flattener has a curved entrance face that matches the Petzval field curvature, allowing the light guides to remain in a flat plane while still achieving sharp projection across the entire field. The field flattener mediates between the flat light guide array and the curved focal surface requirement of the lens.
2Manufacturing precision
If the light guides have variable lengths to match the curved focal surface, then the projection sharpness is improved, but the choice of materials for the primary optical element is limited
Solution Approach 1:
The field-correcting optical element serves as a mediator that allows the use of materials like polycarbonate or PMMA for the primary optical element, which would otherwise be unsuitable due to their inability to accommodate variable-length light guides. The field flattener compensates for the curvature mismatch, enabling the use of injection-moldable materials with uniform light guide lengths.
3Manufacturing precision
If a field-correcting optical element is added to correct the Petzval field curvature, then the projection sharpness and material versatility are improved, but the device complexity increases
Solution Approach 1:
The field-correcting optical element is merged with either the primary optical element or the projecting lens, combining multiple functions into a single integrated component. This reduces the overall device complexity by eliminating the need for separate mounting and alignment mechanisms for the field flattener.
4Ease of manufacture
If the light guides are made with identical lengths in a flat plane, then the ease of manufacture is improved, but the projection sharpness deteriorates due to Petzval field curvature
Solution Approach 1:
The field-correcting optical element acts as an intermediary that enables the use of simple flat-mounted light guides with identical lengths while still achieving sharp projection. The field flattener compensates for the Petzval curvature, allowing the light guides to remain in a flat plane without sacrificing projection quality.
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 ensures clear projection of all secondary elementary light sources, improving manufacturing ease and material options, resulting in uniform light distribution and enhanced adaptive driving beam performance.
Implementation Method 1
a field-correcting second optical element (34) which is designed so that an object focal plane of the projecting lens (14) coincides with the emission plane (P)
Implementation Method 2
a projecting lens (14) that is arranged longitudinally at a distance in front of the matrix array of elementary light sources and that is able to project the image of the elementary light sources
Implementation Method 3
The light guides of the primary optical element extend, on the whole, longitudinally from an entrance face for the light to an exit face for the light
Data Source
AI summary
An optical module for a motor vehicle, the module having a longitudinal optical axis including a matrix array of elementary light sources emitting from a common emission plane that is orthogonal to the optical axis, and a projecting lens for projecting the image of the elementary light sources. The projecting lens includes an object focal surface having a curvature defect. A field-correcting optical element is interposed between the emission plane and the projecting lens.