Optical Scanner Light-Receptive Field Angle Adjustment

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Solution Overview

Problem

Existing optical scanners face accuracy issues due to the scanning speed of light deflectors, leading to insufficient light-receptive field angles and potential failure in object detection, especially at longer distances.

Innovation Solution

The light-receptive field angle of the optical scanner is set to be greater than or equal to the angle of divergence of laser beams and the scanning angular speed, ensuring reliable light reception despite the shifting angles caused by scanning speed and distance, using a configuration that optimizes the light-emitting and light-receptive field angles based on the scanning characteristics of the light deflector.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the scanning angular speed of the light deflector is increased, then the productivity of the optical scanner is improved, but the measurement precision of object detection deteriorates due to angle shifting

Engineering Contradiction:
Improvescanning speedVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by measuring the actual scanning angular speed of the light deflector and using this information to dynamically adjust the light-receptive field angle. The control unit continuously monitors the scanning speed and modifies the receptive field parameters in real-time to compensate for angle shifts, ensuring that the light receiver maintains proper alignment with the returning light regardless of scanning speed variations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the light-receptive field angle based on the scanning angular speed. When the scanning speed changes, the system modifies the receptive field parameters (angle and duration) to match the new scanning conditions, thereby maintaining detection accuracy across different scanning speeds without requiring a fixed geometric configuration.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the light-receptive field angle is widened to cover angle shifts, then the reliability of light reception is improved, but the device complexity increases

Engineering Contradiction:
Improvelight reception reliabilityVSAvoidoptical system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the light-receptive field angle variable rather than fixed. The optical system dynamically adjusts the receptive field angle according to the actual scanning speed, transforming a static geometric configuration into a dynamic, adaptive system that maintains reliability without requiring excessive angular margin in all conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of the light-receptive field angle based on operating conditions. By adjusting this parameter dynamically, the system achieves reliable light reception only when necessary (when angle shifts occur) rather than maintaining a permanently wide receptive field, thereby balancing reliability with device simplicity.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the detection distance is increased, then the productivity of the optical scanner is improved, but the measurement precision deteriorates due to larger angle shifts

Engineering Contradiction:
Improvedetection distanceVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The control unit uses feedback from the measured scanning angular speed to adjust the light-receptive field parameters. This feedback mechanism allows the system to compensate for the increased angle shifts that occur at longer detection distances, maintaining measurement precision while extending the detection range by adapting the receptive field to the actual optical path conditions.

Inventive Principle:
Principle #23Feedback

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 configuration ensures reliable detection of objects with high precision across various distances, even with slow scanning speeds, by ensuring the light-receptive field angle covers the movement of the light deflector and maintains accurate angle alignment for both emitted and received laser beams.

Implementation Method 1

a light deflector that deflects laser beams emitted from a light emitter

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a photodetector detects the light reflected or dispersed from the object

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3761056B1Optical scanner, object detector, and sensing apparatus
Publication Date: 2023.01.25 RICOH CO LTD
  • EP3761056B1 patent drawingFigure 1
  • EP3761056B1 patent drawingFigure 2
  • EP3761056B1 patent drawingFigure 3

AI summary

An optical scanner (1) includes a light source unit (10, 20) configured to emit a laser beam, a light deflector (30) configured to deflect and scan the laser beam emitted from the light source unit (10, 20) towards an object existing in a detection field, and a light-receptive optical device (50) configured to receive the laser beam deflected and scanned by the light deflector (30) and then reflected or scattered by the object existing in the detection field. A light-receptive field angle (θr) of the light-receptive optical device (50) is determined based on a scanning angular speed of the light deflector (30), a longest detection distance (L) of the object in the detection field, and an angle of divergence (θt) of the laser beam in the detection field.