Vehicular Lamp Optical Shutter with Compensation Plates
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Solution Overview
Problem
Existing vehicle headlight systems struggle to achieve high contrast in light distribution patterns due to the wide angular range of light emission and the reliance on liquid crystal elements, which results in reduced contrast and light leakage.
Innovation Solution
A vehicular lamp system incorporating a light source, an optical shutter part with polarizers, a liquid crystal element, and optical plates (A-plates and C-plates) that modulate light based on electric field alignment changes, enhancing light distribution patterns by compensating for viewing angles and reducing light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a liquid crystal element is used to control light emission in a wide angular range, then light can be emitted broadly, but the contrast of the projected image is reduced due to viewing angle dependence
Solution Approach 1:
The patent introduces optical compensation plates (A-plate and C-plate) as intermediary elements between the light source and liquid crystal element. These plates mediate the optical interaction by compensating for viewing angle effects, allowing broad angular emission while maintaining image contrast through optical path correction
Solution Approach 2:
The patent changes the optical parameters of the system by introducing compensation plates with specific retardation values and orientation angles. These parameter changes compensate for the viewing angle dependence of the liquid crystal element, maintaining consistent contrast across different emission angles
2Manufacturing precision
If light is collected using a lens to be incident on the liquid crystal element at narrow angles, then the incident angle is reduced, but the light transmission and contrast are still reduced due to the inherent viewing angle dependence of liquid crystal elements
Solution Approach 1:
The compensation plates serve as intermediary optical elements that correct the viewing angle dependence before light reaches the liquid crystal element. This mediation allows the system to maintain high light transmission and contrast even when light must be collected at narrow angles
Solution Approach 2:
The patent creates a composite optical system combining the liquid crystal element with compensation plates having specific optical properties. This composite structure compensates for the limitations of individual components, achieving both narrow angle incidence and high light transmission
3Area of stationary object
If the light distribution pattern is projected forward, then the surrounding area is illuminated, but light leakage occurs and contrast is reduced
Solution Approach 1:
The compensation plates act as intermediary elements that prevent light leakage by correcting optical paths. They mediate between the broad illumination requirement and the need for precise light control, blocking stray light while maintaining contrast in the projected image
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 system achieves high contrast and improved light distribution patterns by effectively modulating light across a wide angular range, enhancing visibility and reducing light leakage, thereby improving the quality of projected images in vehicle headlamps.
Implementation Method 1
a liquid crystal element in which an initial alignment of liquid crystal molecules is horizontally aligned and causes an alignment change in the in-plane direction upon application of an electric field
Implementation Method 2
a first optical plate which is a positive A-plate disposed between one of the pair of polarizers closer to the light source and the liquid crystal element; and a second optical plate which is a positive C-plate disposed between the first optical plate and the liquid crystal element
Data Source
Figure 1
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AI summary
To obtain projection images with high contrast when selective light irradiation is performed forward of its own vehicle. A lamp unit for a vehicular lamp system performing selective light irradiation to the surroundings of the own vehicle includes: a light source; an optical shutter part that modulates light emitted from the light source; and an optical system that projects the light transmitted through the optical shutter part. The optical shutter part includes: polarizers; a liquid crystal element disposed between the polarizers and where the initial alignment of liquid crystal molecules is horizontally aligned and causes an alignment change in the in-plane direction upon electric field application; a first optical plate which is a positive A-plate disposed between the polarizers closer to the light source and the liquid crystal element; and a second optical plate which is a positive C-plate disposed between the first optical plate and the liquid crystal element.