Imaging Device Inclined Light Sources Reduce Interference

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing imaging devices face challenges in downsizing and cost reduction due to the interference of spot lights when using inexpensive light sources, which degrades detection accuracy and increases costs with complex lens structures.

Innovation Solution

The imaging device employs a structure where multiple light sources are arranged around the imaging element with inclined optical axes, reducing light interference and allowing the use of low-cost LEDs, while maintaining detection accuracy through specific angle and distance calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser is used for distance detection, then detection accuracy is improved, but cost increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidcost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces expensive laser light sources with inexpensive LED light sources. While LEDs have shorter coherence length and lower inherent precision compared to lasers, the patent compensates through optical design (lens structure) and signal processing techniques, achieving sufficient detection accuracy at lower cost.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the operating parameters of the LED light source, including emission wavelength selection and pulse width modulation, to optimize performance for distance detection. By adjusting these parameters and combining with specific lens focal lengths and aperture designs, the system achieves laser-like detection capability without laser costs.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If an LED is used instead of a laser, then cost is reduced, but focusing degree is degraded

Engineering Contradiction:
ImprovecostVSAvoidfocusing degree
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent introduces a specifically designed lens as an intermediary optical element between the LED light source and the detection target. This lens compensates for the LED's inferior focusing capability by providing precise light convergence, effectively bridging the gap between inexpensive LED sources and the need for tight focal spots.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite optical system combining LED light source with precision-engineered lens materials. The lens is designed with specific refractive index and curvature parameters to compensate for the LED's divergent light output, creating a composite optical path that achieves the required focusing degree despite using inexpensive LED components.

Inventive Principle:
Principle #40Composite materials

3Volume of moving object

If multiple light sources are arranged closely for downsizing, then device size is reduced, but light interference increases

Engineering Contradiction:
Improvedevice sizeVSAvoidlight interference
Core Design Contradiction:
Volume of moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent segments the optical path of each light source by providing individual lenses for each LED. This segmentation allows each light source to be independently focused and directed, reducing cross-interference between adjacent light sources while maintaining compact spacing. Each lens acts as an independent optical channel, preventing light from one LED from interfering with the detection path of another.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality optimization by designing each light source-lens combination with specific angular characteristics tailored to its position in the array. The lenses are designed with different focal lengths and aperture angles suited to their local requirements, allowing light from each source to be precisely directed at the target while minimizing overlap and interference with adjacent sources.

Inventive Principle:
Principle #3Local quality

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

This approach enables cost-effective downsizing of imaging devices without compromising detection accuracy, as the inclined light sources minimize interference and eliminate the need for high-accuracy lens structures, making the technology suitable for small and affordable devices.

Implementation Method 1

a light source 20 and a lens 22 arranged on the light source 20

Methodology Applied
Scientific EffectLight emission: Light

Implementation Method 2

a focusing degree is degraded

Methodology Applied
Scientific EffectLight focusing: Focusing

Implementation Method 3

an imaging element 10 for taking an image of a subject

Methodology Applied
Scientific EffectOptical detection: Photography

Data Source

PatentEP2833095B1Imaging device
Publication Date: 2023.06.28 FUJITSU LTD
  • EP2833095B1 patent drawingFigure 1A~1B
  • EP2833095B1 patent drawingFigure 2
  • EP2833095B1 patent drawingFigure 3A~3B

AI summary

An imaging device includes: an imaging element that take an image of a subject; and a plurality of light sources that radiate a light to the subject, wherein optical axes of the plurality of the light sources are inclined outward with respect to an optical axis of the imaging element.