Liquid Crystal Headlamp Optics for Fail-Safe Beam Control
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Solution Overview
Problem
Current adaptive driving beam (ADB) car headlights face challenges in high manufacturing costs due to the need for multiple current sources for LEDs and have low light utilization ratios, with liquid crystal devices being prone to failure and heating issues that affect fail-safe security and precision in light distribution control.
Innovation Solution
The design eliminates polarizers in regions where light distribution control is not necessary, enhancing light utilization and maintaining fail-safe security by using a liquid crystal device with strategically positioned polarizers and analyzers to control light polarization, ensuring high transmissivity and precise polarization control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polarizers are disposed on both sides of the liquid crystal layer to control light transmission, then light distribution pattern control precision is improved, but light utilization ratio deteriorates
Solution Approach 1:
The patent divides the liquid crystal device into multiple regions: a first region with both polarizer and analyzer for precise light distribution control, and a second region with only polarizer for high light transmission. This segmentation allows different parts of the device to serve different functions, resolving the contradiction between control precision and light utilization.
Solution Approach 2:
Different regions of the liquid crystal device are assigned different optical qualities: the first region has crossed polarizers for precise control, while the second region has a single polarizer for high transmission. This local differentiation optimizes both control precision where needed and light utilization where control is less critical.
2Measurement precision
If a normally black mode liquid crystal device is used with crossed Nicol polarizers, then light distribution control performance is improved, but fail-safe security deteriorates due to blackout on failure
Solution Approach 1:
The device is segmented into a first region with crossed polarizers for high-performance control and a second region with a single polarizer that provides fail-safe illumination. This ensures that if the liquid crystal fails, the second region continues to transmit light, maintaining visibility and safety.
Solution Approach 2:
The second region with the single polarizer acts as a pre-prepared backup system. In case of liquid crystal failure, this region immediately provides compensatory light transmission, cushioning against the potential blackout and maintaining fail-safe security without requiring active intervention.
3Measurement precision
If polarizers are disposed close to the liquid crystal layer for precise polarization control, then light distribution precision is improved, but heating effects on the liquid crystal layer worsen
Solution Approach 1:
The patent resolves the heating issue by changing the spatial arrangement: instead of placing polarizers immediately adjacent to the liquid crystal layer, they are positioned at a distance in the optical path. This dimensional adjustment reduces direct heat transfer to the liquid crystal while maintaining polarization control functionality through the optical path.
4Adaptability or versatility
If multiple current sources are used to control drive currents for multiple LEDs in matrix configuration, then light distribution adaptability is improved, but manufacturing cost worsens
Solution Approach 1:
The liquid crystal device serves multiple functions: it controls light distribution patterns, provides adaptive beam shaping, and enables both high beam and low beam modes. This multi-functionality replaces the need for multiple independently controlled LED arrays, reducing the number of current sources required and simplifying the overall system while maintaining adaptability.
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 approach reduces manufacturing costs, improves light utilization, and maintains fail-safe security by optimizing light distribution control, particularly in the near field region, while ensuring precise polarization control and minimizing heating effects on the liquid crystal layer.
Implementation Method 1
electrodes are disposed on both sides of the liquid crystal layer to apply voltage across the liquid crystal layer so as to control the orientation of the liquid crystal molecules
Implementation Method 2
A polarizer receives incident light and extracts light component having specified polarization
Data Source
Figure 1A~1C
Figure 2A~2C
Figure 3A~3B
AI summary
A lighting device includes: a liquid crystal element having electrode pattern including a first portion and a second portion; drive circuit connected to the electrode pattern; polarizer disposed in front of the liquid crystal element and separated from the liquid crystal element in optical axis direction; analyzer disposed at rear of the liquid crystal element, and separated from the liquid crystal element in optical axis direction, wherein the polarizer and the analyzer constitute crossed Nicol polarizers; light source for supplying lights to the liquid crystal element within a predetermined incident angle range; and projection optical system projecting lights transmitted through the liquid crystal element forwardly; wherein the polarizer and the analyzer locally overlap with the liquid crystal element in projection normal to the liquid crystal element, and when the light source is turned on, the drive circuit supplies drive signal to the first portion of the electrode pattern which applies or releases voltages in compliance with circumstances, and supplies drive signal to the second portion of the electrode pattern which continuously applies voltage, lights transmitting through the first portion of the electrode pattern and projecting forward transmit both the polarizer and the analyzer, and lights transmitting through the second portion of the electrode pattern and projecting forward include components which do not transmit at least one of the polarizer and the analyzer.