Vehicle Headlamp Two-Dimensional Optical Deflector Scan Line Irregularity
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Solution Overview
Problem
Existing vehicle headlamps with two-dimensional optical deflectors suffer from irregular illumination near the cut-off boundary line due to observable scan lines and lack a bright center portion, especially when scanning along horizontal lines.
Innovation Solution
A control circuit is implemented to adjust the size and luminance of the spotlight by controlling the lens actuator and light source, respectively, with varying drive voltages, ensuring larger line widths and luminance closer to the cut-off boundary line, thereby achieving a bright center portion and smoother illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the spotlight is scanned uniformly along the horizontal line with high frequency by the first actuator, then the density of scan lines increases and distant visibility improves, but the scan lines remain clearly observable causing irregularity of illumination
Solution Approach 1:
The patent applies local quality by varying the spot size dynamically across different vertical positions. Specifically, the spot size is enlarged near the cut-off boundary line and reduced in other areas, creating locally adapted illumination characteristics that smooth out the scan line effects where they are most problematic while maintaining resolution where needed
Solution Approach 2:
The patent changes the physical parameter of spot size (diameter) as a function of vertical position and time. By dynamically adjusting this parameter, the system transforms the uniform scan into a variable-density illumination pattern that eliminates visible scan lines near the cut-off boundary while maintaining high-frequency scanning benefits in other regions
2Area of stationary object
If the mirror is rocked with respect to the Y-axis for vertical deflection at low frequency, then the illumination area is covered, but a bright center portion as required for the vehicle is not realized
Solution Approach 1:
The patent applies local quality by creating a bright center portion through concentrated illumination in the central horizontal region. The spot size modulation and scanning pattern are designed to accumulate light energy in the center area, providing enhanced brightness where it is most needed for vehicle visibility while maintaining comprehensive area coverage
Solution Approach 2:
The patent uses preliminary action by pre-positioning the spotlight to trace horizontal lines that converge toward the center portion before the vertical scan completes. This ensures that the center area receives accumulated illumination from multiple horizontal passes, creating the desired bright center effect
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 solution enhances the regularity of illumination and provides a bright center portion, addressing the irregularity and brightness issues near the cut-off boundary line, improving distant visibility and reducing the visibility of scan lines.
Implementation Method 1
a first piezoelectric actuator for rocking the mirror with respect to an X-axis of the mirror, a support body surrounding the movable frame, and a second piezoelectric actuator for rocking the mirror through the movable frame with respect to a Y-axis of the mirror
Implementation Method 2
a lens actuator for changing a size of the spotlight transmitted through the lens
Implementation Method 3
a two-dimensional optical deflector for reflecting the spotlight to ahead of a vehicle. The two-dimensional optical deflector includes a mirror for reflecting the spotlight from the light source
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A headlamp for a vehicle includes a light source (15, 15R, 15G, 15B) adapted to emit a spotlight (S), a lens (16, 16R, 16G, 16B) adapted to receive and transmit the spotlight, a lens actuator (17, 17R, 17G, 17B) adapted to adjust a size (D) of the spotlight transmitted through the lens, a two-dimensional optical deflector (18) adapted to deflect the spotlight from the lens to an illumination area ahead of the vehicle, and a control circuit (19) configured to control the lens actuator in such a way that irregularity of illumination in the illumination area is avoided.