Vehicular Headlight Contrast Control for Bad Weather Visibility

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Solution Overview

Problem

Existing vehicular lighting systems struggle to improve visibility in bad weather conditions such as rainfall, snowfall, and fog, as light is often reflected or obscured, leading to reduced visibility of the road shape and potential whiteout scenarios.

Innovation Solution

A vehicular lighting apparatus equipped with a camera for image processing, sensors for weather detection, and an Electronic Control Unit (ECU) that adjusts the luminous intensity distribution of the headlight to enhance visibility by reducing light quantity in specific areas, creating contrast with normal irradiation zones and displaying aid lines, thereby guiding the driver through reduced light areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the headlight irradiates the front of the vehicle with high light quantity to improve visibility, then the visibility of the travelling route should be improved, but in bad weather conditions (rainfall, snowfall, fog) the light is reflected or obscured causing reduced visibility and whiteout scenarios

Engineering Contradiction:
Improvevisibility of travelling routeVSAvoidlight reflection and veiling phenomena in bad weather
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating different luminous intensity zones within the irradiation range. Specifically, a first luminous intensity distribution illuminates the road surface in the traveling route with reduced light quantity, while a second luminous intensity distribution provides normal or enhanced illumination in surrounding areas. This local differentiation creates contrast that helps the driver distinguish the road shape from the background in bad weather conditions.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent inverts the conventional approach by reducing light quantity in the critical area (road surface in traveling route) rather than increasing it uniformly. This counterintuitive strategy creates visibility through contrast: the reduced illumination area stands out against the normally illuminated background, allowing the driver to perceive the road shape despite the overall reduced visibility caused by rain, snow, or fog.

Inventive Principle:
Principle #13The other way round (Inversion)

2Illumination intensity

If the headlight uses uniform luminous intensity distribution to illuminate the front, then the overall illumination is sufficient, but the contrast between road surface and background is reduced in bad weather conditions

Engineering Contradiction:
Improveoverall illuminationVSAvoidroad shape visibility due to reduced contrast
Core Design Contradiction:
Illumination intensityVSLoss of information

Solution Approach 1:

The patent implements local quality by creating a non-uniform luminous intensity distribution where specific zones have different illumination levels. The control unit generates a first luminous intensity distribution that reduces light quantity in the road surface area of the traveling route, while maintaining normal illumination in other areas. This local differentiation preserves overall illumination while enhancing road shape visibility through contrast.

Inventive Principle:
Principle #3Local quality

3Loss of information

If the headlight reduces light quantity in the road surface zone to create contrast, then the visibility of road shape is improved, but the overall illumination of the front area is reduced

Engineering Contradiction:
Improveroad shape visibilityVSAvoidoverall illumination of front area
Core Design Contradiction:
Loss of informationVSIllumination intensity

Solution Approach 1:

The patent applies segmentation by dividing the irradiation range into distinct zones with different luminous intensity characteristics. The control unit segments the light distribution into a first luminous intensity distribution (reduced intensity in road surface zone of traveling route) and a second luminous intensity distribution (normal or enhanced intensity in surrounding areas). This segmentation allows the system to improve road shape visibility in the critical zone while maintaining overall illumination through the second distribution.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2965946B1Vehicular lighting apparatus
Publication Date: 2023.01.11 TOYOTA JIDOSHA KK
  • EP2965946B1 patent drawingFigure 1
  • EP2965946B1 patent drawingFigure 2A~2B
  • EP2965946B1 patent drawingFigure 3~4

AI summary

A vehicular lighting apparatus (1) includes a headlight (300) that irradiates the front of a vehicle; a condition detection part (210) that detects a weather condition at a position of the vehicle; a travelling route estimation part (230) that estimates a road shape of a travelling route in front of the vehicle; and a control part (200) that controls a luminous intensity distribution of the headlight. The control part controls the headlight in such a manner as to irradiate a road surface zone (DA1, DA2) in front of the vehicle with a reduced quantity of light when the condition detection part detects such a weather condition as to cause a low visibility in front of the vehicle, the road surface zone in front of the vehicle corresponding to the road shape of the travelling route estimated by the travelling route estimation part.