Cabin IR Illumination Lens Array to Reduce Driver Red Glow

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Solution Overview

Problem

The red glow effect caused by infrared light rays emitting from motor vehicle cabin sensing systems can distract drivers, compromising safety due to the detection of these light rays by human eyes, especially in low ambient lighting conditions.

Innovation Solution

A motor vehicle cabin sensing system that employs an illumination lens array with multiple single lens elements to diffuse infrared light rays, reducing the radiant intensity detected by the retina to 0% to 50% of the original light source, thereby minimizing driver distraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared illumination source is used to capture driver images, then image quality for facial recognition is improved, but red glow effect is generated causing driver distraction

Engineering Contradiction:
Improvefacial recognition accuracyVSAvoiddriver distraction from red glow
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The illumination source is divided into multiple lens elements (e.g., microlens array) that segment the infrared light into multiple beams. This segmentation distributes the light intensity across different angles, reducing the concentrated radiant intensity that causes red glow effect while maintaining sufficient illumination for image capture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the illumination system are assigned different functions: the microlens array elements are designed to create specific beam patterns, with some elements directing light toward the driver's face for imaging while others distribute light to reduce hotspots. This local differentiation optimizes both image quality and reduces distracting glare.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If high intensity infrared light is emitted, then image sensor performance is improved, but radiant intensity detected by retina increases causing discomfort

Engineering Contradiction:
Improveimage sensor detection capabilityVSAvoidretinal radiant intensity
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The illumination system transitions from a single-point source to a multi-dimensional beam distribution through the microlens array. By spreading light across multiple angular dimensions rather than a single concentrated beam, the system achieves sufficient total illumination for the image sensor while reducing the intensity in any single direction (particularly toward the driver's eyes).

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reduces the radiant intensity of the red glow effect by 10 to 100 times, enhancing driver safety by minimizing visual discomfort caused by the infrared light emission.

Implementation Method 1

an illumination lens array operable to diffuse the light rays emitting from the illumination source towards the motor vehicle cabin

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP4279978A1A motor vehicle cabin sensing system
Publication Date: 2023.11.22 CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
  • EP4279978A1 patent drawingFigure 1
  • EP4279978A1 patent drawingFigure 2
  • EP4279978A1 patent drawingFigure 3

AI summary

This disclosure relates to a motor vehicle cabin sensing system. The system comprises an image sensor, an illumination source and an illumination lens array. The image sensor is operable to capture one or more images, the image sensor having a field of view of a motor vehicle cabin. Preferably, the image sensor is operable to capture images in a near infrared wavelength. The illumination source is operable to transmit light rays towards the motor vehicle cabin. The illumination lens array is operable to diffuse the light rays emitting from the illumination source to one or more photoreceptor cells of a retina such that a radiant intensity of a red glow effect detected by the retina is a reduction of 10 to 100 times or 0% to 50% of a radiant intensity of the illumination source.