Transverse Lens Shift for Variable Focal Length Headlights
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Solution Overview
Problem
Existing motor vehicle headlight light modules face issues with dust contamination affecting the image quality due to the small reflecting surface of micromirrors in DMD chips, leading to dark spots and washed-out areas in the external light distribution, and the displacement of lenses along the optical axis increases installation depth, making dustproof housing integration challenging.
Innovation Solution
A motor vehicle headlight light module with projection optics that adjust the focal length by moving lenses transversely to the optical axis, using a dustproof housing with separated lenses and an air gap, and an electric motor-driven threaded drive to adjust the lens position, ensuring sharp imaging at various distances and minimizing dust exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If lenses are displaced along the optical axis to adjust focal length, then focal length adjustment is achieved, but installation depth increases making dustproof housing integration difficult
Solution Approach 1:
The patent transitions from axial displacement (along the optical axis) to transverse displacement (perpendicular to the optical axis) of the lenses. This dimensional change allows focal length adjustment while maintaining a compact installation depth that fits within dustproof housing constraints.
Solution Approach 2:
The patent introduces a specific lens arrangement with two lenses (first lens and second lens) that work together as an intermediary system. By displacing these lenses transversely relative to each other, the system achieves focal length adjustment without requiring deep axial movement, thus resolving the contradiction between adaptability and installation depth.
2Productivity
If DMD chip with large number of micromirrors is used, then projection capability is improved, but dust contamination affects image quality due to small reflecting surface
Solution Approach 1:
The patent introduces a dustproof housing as an intermediary protective barrier between the DMD chip and the external environment. This housing prevents dust from reaching the micromirrors while allowing the light path to pass through, thus protecting the projection capability from dust contamination without compromising the projection function.
Solution Approach 2:
The patent separates the DMD chip and projection optics from the external environment by enclosing them in a dustproof housing. This extraction of the sensitive components from the dusty environment eliminates dust contamination while maintaining the projection capability of the DMD chip.
3Length of stationary object
If transverse displacement of lenses is used to adjust focal length, then installation depth is reduced, but lens positioning precision must be maintained
Solution Approach 1:
The patent replaces purely mechanical positioning with a hybrid system that includes electric motor-driven threaded drives for actuator means. This substitution provides precise control over lens displacement positions, ensuring manufacturing and positioning precision while maintaining reduced installation depth.
Solution Approach 2:
The patent incorporates control means that can monitor and adjust lens positions, providing feedback control to maintain precise positioning during transverse displacement. This ensures that the reduced installation depth does not compromise positioning precision.
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 a dustproof and effective light distribution adjustment mechanism, maintaining image quality across different distances while reducing the risk of dust contamination and simplifying integration into a dustproof housing, ensuring clear and focused light projection.
Implementation Method 1
The first lens (42.1) and the second lens (42.2) are set up to react to the change in position with a change in the focal length of the projection optics (20)
Implementation Method 2
a displacement of the two lenses relative to one another transverse to the direction of the light passing through the lenses changes the refractive power of the lens system formed from the two lenses
Data Source
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AI summary
A motor vehicle headlight is presented, comprising a light module (16) that projects an internal light distribution using a projection optic (20) comprising a first lens (42.1) and a second lens (42.2). The light module projects the internal light distribution as an external light distribution. The projection optic has an actuating mechanism (24) for adjusting its focal length. The actuating mechanism (24) changes the position of at least one of the two lenses (42.1, 42.2) relative to the other. This position is changed by shifting the first lens (42.1) relative to the second lens (42.2) and/or the second lens (42.2) relative to the first lens (42.1) perpendicular to an optical axis of the projection optic. The first and second lenses respond to the change in position by changing the focal length of the projection optic.