Variable Focus Lens for Vehicle Imaging System Window Condition Detection

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Solution Overview

Problem

Imaging systems in vehicles face disruptions due to degraded optical quality of vehicle windows, such as fog, frost, and reflections, which can lead to false warnings and incorrect target identification, and existing solutions like polarizing elements or non-reflecting shields are either ineffective or require redesign for each vehicle model.

Innovation Solution

An imaging system with a variable focus lens that can adjust its shape to image both objects outside the vehicle and the window, allowing for analysis of the window's condition and providing alerts to the driver when the optical quality is unacceptable, using a controller to switch between configurations based on image analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a non-reflecting light shield is placed underneath the optics to prevent reflections from entering the imaging system, then reflections from dashboard objects are eliminated, but the shield is large and requires redesign for each vehicle model

Engineering Contradiction:
Improvereflections from dashboard objectsVSAvoidshield design complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies universality by making the imaging system itself multi-functional: it can image both external objects and the windshield surface by varying the focal length. This eliminates the need for separate reflection-blocking shields, as the system adapts its function based on the imaging target. The controller automatically switches between imaging modes (external scene vs. windshield inspection) without requiring model-specific shield designs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent employs dynamics through the variable focal length lens that can dynamically adjust between two focal lengths. This dynamic adjustment allows the system to switch between imaging external objects and inspecting the windshield surface. The focal length is varied based on detected conditions (e.g., application failures, driver alerts), enabling the system to adapt its optical configuration in real-time without physical modification.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If a polarizing element is included to eliminate polarized reflections from the windshield, then reflections are reduced, but the detector sensitivity is cut by half as half of the incoming light is eliminated

Engineering Contradiction:
Improvepolarized reflections from windshieldVSAvoiddetector sensitivity
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

Instead of using a static polarizing element that permanently blocks half the light, the patent employs a dynamic solution: a variable focal length lens that can switch between imaging external objects and inspecting the windshield surface. The system dynamically adjusts the focal length based on detected conditions, allowing full light transmission during normal operation while enabling reflection analysis when needed, thus maintaining detector sensitivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback mechanisms to determine when windshield inspection is necessary. The controller monitors for application failures, driver alerts, or other indicators that suggest windshield contamination or damage. Based on this feedback, the system automatically adjusts the focal length to inspect the windshield surface, rather than continuously blocking light with a polarizer. This feedback-driven approach maintains optimal sensitivity while enabling on-demand inspection.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the imaging system continuously monitors for window conditions, then window condition detection accuracy is improved, but the imaging system performance for primary applications may be compromised due to frequent focus adjustments

Engineering Contradiction:
Improvewindow condition detection accuracyVSAvoidimaging system performance
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements periodic action by monitoring window conditions at specific intervals or under specific triggering conditions rather than continuously. The controller adjusts the focal length to inspect the windshield surface based on detected events such as application failures, driver alerts, or periodic schedules. This event-driven or periodic monitoring approach maintains high detection accuracy while minimizing disruptions to the primary imaging applications, as the system remains in its primary imaging mode most of the time.

Inventive Principle:
Principle #19Periodic action

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 effectively improves the accuracy of imaging applications by adjusting the focal length to diagnose and address window conditions, reducing false warnings and enhancing the overall performance of vehicle imaging systems without compromising light sensitivity or requiring model-specific designs.

Implementation Method 1

imaging optics including a variable focus lens and having a first configuration wherein an object spaced apart from the vehicle is imaged onto the detector and a second configuration wherein at least a portion of the window is imaged onto the detector

Methodology Applied
Scientific EffectVariable focus lens shape adjustment: Lens

Implementation Method 2

The condition or optical quality of the window through which the imaging system looks may impede the operation of the imaging system

Methodology Applied
Scientific EffectLight transmission and reflection: Reflection

Implementation Method 3

It is known to detect the presence of precipitation on a windshield of a vehicle by total internal reflection. A beam of light is reflected from the windshield at a particular angle.

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP1819167B1Method for determining windshield condition and an improved vehicle imaging system
Publication Date: 2014.06.11 DELPHI TECHNOLOGIES INC
  • EP1819167B1 patent drawingFigure 1
  • EP1819167B1 patent drawingFigure 2
  • EP1819167B1 patent drawingFigure 3

AI summary

An imaging system (110) for use in a vehicle (100) is disclosed wherein the imaging system (110) images an object (112)spaced apart from the vehicle (100) in a first configuration and images an object (144) supported by the vehicle (100) in a second configuration. The imaging system (110) may include a fluid lens. An imaging system (110) for use in a vehicle (100) is disclosed wherein the imaging system (110) has a first configuration corresponding to a first imaging application (126A) and a second configuration corresponding to a second imaging application (126B). The imaging system (110) may include a fluid lens.