Vehicle Mirror Reflectance Control Using Rear Camera Luminance

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Solution Overview

Problem

Existing vehicle mirrors with anti-glare functions require light quantity sensors, which constrain design and are difficult to integrate with room lighting, and their absence leads to ineffective glare control.

Innovation Solution

A controller that uses a camera to capture images behind the vehicle, determining mirror reflectance based on luminance to automatically adjust reflectance and control glare without light quantity sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two light quantity sensors are provided in the mirror for detecting light from front and rear, then anti-glare control can be automatically performed, but the mirror design becomes constrained and difficult to integrate with room lighting

Engineering Contradiction:
Improveanti-glare controlVSAvoidmirror design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The light detection function is extracted from the mirror and relocated to the rear camera. The camera captures images of the rear environment, and the control unit analyzes luminance in these images to determine when anti-glare control is needed, eliminating the need for dedicated light quantity sensors in the mirror

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The rear camera serves multiple functions: it provides both rearview monitoring functionality and light detection for anti-glare control. By analyzing luminance in the captured images, the same imaging device performs dual purposes, reducing overall system complexity

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

2Reliability

If light quantity sensors are provided in the mirror, then anti-glare control can be performed, but the number of devices increases and costs increase

Engineering Contradiction:
Improveanti-glare controlVSAvoidnumber of devices
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The rear camera is utilized for dual purposes: rearview monitoring and light detection for anti-glare control. The control unit analyzes luminance in the captured images to determine when anti-glare is needed, allowing one device to perform multiple functions and reducing the total number of components

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

Solution Approach 2:

The rear camera system serves itself by using its captured images not only for monitoring but also for controlling the mirror's anti-glare function. The luminance information from the camera images directly informs the anti-glare control decisions

Inventive Principle:
Principle #25Self-service

3Reliability

If light quantity sensors are provided in the mirror, then anti-glare control can be performed, but obstructions in driver's field of view occur and aesthetic appearance deteriorates

Engineering Contradiction:
Improveanti-glare controlVSAvoiddriver's field of view
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The light detection function is extracted from the mirror and relocated to the rear camera system. This removes physical sensors from the mirror surface, eliminating obstructions in the driver's field of view and preserving the mirror's aesthetic appearance while maintaining anti-glare functionality

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If no light quantity sensor is provided in the mirror, then design constraints are reduced, but appropriateness of anti-glare control is lost

Engineering Contradiction:
Improvemirror designVSAvoidanti-glare control
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The rear camera images serve as an intermediary medium for light detection. Instead of directly measuring light with sensors in the mirror, the system uses the captured images as an intermediate representation of the rear environment's luminance conditions to control anti-glare

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables effective glare control by dynamically adjusting mirror reflectance based on actual environmental lighting conditions, ensuring appropriate anti-glare without the need for additional sensors.

Implementation Method 1

a camera configured to capture an image of a view behind the vehicle

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

a mirror which is provided in a vehicle cabin and configured to be capable of changing reflectance

Methodology Applied
Scientific EffectReflectance control: Reflection

Data Source

PatentEP4530129B1Controller, control system and control method
Publication Date: 2026.02.25 ALPS ALPINE CO LTD
  • EP4530129B1 patent drawingFigure 1~2
  • EP4530129B1 patent drawingFigure 3
  • EP4530129B1 patent drawingFigure 4

AI summary

A controller is provided for performing processes related to a mirror which is provided in a vehicle cabin and configured to be capable of changing reflectance. The controller includes a control unit configured to acquire a captured image based on a result of imaging by a camera configured to capture an image of a view behind the vehicle; and to determine a mirror reflectance, which is the reflectance of the mirror, based on a state of luminance of the captured image.