Headlight Division Scan Optical System for Bright Center Light Distribution
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Solution Overview
Problem
Prior-art headlights using optical deflectors driven by sinusoidal or sawtooth wave voltages result in scan lights that are brighter at the center and darker at the ends of the irradiation region, which is opposite to the desired light distribution pattern.
Innovation Solution
The headlight divides the rotation angle range of the reflection unit into two portions, using a V-shaped mirror or diamond prism to direct the reflection light such that the center part of the irradiation region is scanned by light of one end angle and the end portions by light of intermediate angle, achieving a brighter center and darker ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the actuator is driven by a sinusoidal wave or sawtooth wave voltage, then the reflection unit can reciprocate and rotationally move around two rotation axes, but the scan light has its scan speed lowered at both end portions and increased at the center part, resulting in a light distribution pattern where the center is dark and ends are bright
Solution Approach 1:
The patent divides the rotation angle range of the reflection unit into two distinct ranges: a first rotation angle range where the reflection unit reciprocates around a first rotation axis, and a second rotation angle range where it reciprocates around a second rotation axis. This segmentation allows different portions of the scan light to be directed to different regions of the irradiation area, enabling the center-bright, ends-dark light distribution pattern to be achieved while maintaining smooth scan operation.
2Area of stationary object
If the reflection unit is rotated by a driving voltage, then the scan light can cover the irradiation region, but the scan speed is in proportion to the temporal differentiation of the driving voltage, causing non-uniform illumination
Solution Approach 1:
The patent applies local quality by making different regions of the irradiation area receive light with different characteristics. Specifically, the center region is scanned by scan light from one end of the rotation angle range where the temporal differentiation of driving voltage is lower, while the end regions are scanned by light from intermediate angles where the differentiation is higher. This creates the desired non-uniform illumination pattern with bright center and dark ends.
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 configuration generates a light distribution pattern where the center of the irradiation region is bright and the end portions are dark, enhancing contrast and allowing for adjustable light distribution patterns during vehicle turns or switching between high and low beams.
Implementation Method 1
a piezoelectric film as the actuator which reciprocating and rotationally moves the reflection unit around two rotation axes orthogonal to each other
Implementation Method 2
a reflection unit for reflecting light... the light incident to the reflection unit from a laser light source or the like is reflected by the reflection unit
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A division scan optical system (13) has a dividing unit (41) which divides a first rotation angle range of a reflection unit (22) of an optical deflector into right scan light (Lb1) of a first angle portion from one end angle to an intermediate angle and a left scan light (Lb2) of a second angle portion from the intermediate angle to the other end angle, a right-side scan light generation unit (46a) which causes reflection light which is the closer to the one end angle in the reflection light of the first angle portion to advance on a left side in a horizontal direction and emits the light as scan light which scans a right-side region portion of an irradiation region in a horizontal direction, and a left-side scan light generation unit (46b) which causes the reflection light which is the closer to the other end angle in the reflection light of the second angle portion to advance on a right side in the horizontal direction and emits the light as scan light which scans a left-side region portion of the irradiation region in a horizontal direction.