Laser Optical Axis Detection Using Split Beams and One Sensor

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Solution Overview

Problem

Existing optical axis correction devices for laser light suffer from inaccurate position detection due to sensor sensitivity variations and measurement errors caused by changes in the positional relationship between sensors, particularly due to thermal effects.

Innovation Solution

A detection device that splits laser light into multiple beams with different optical path lengths, using a single sensor to detect the position of each beam, and a processor to calculate angular or positional deviations, thereby correcting the optical axis with improved accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If two sensors are used to detect laser light position, then detection coverage is improved, but measurement accuracy deteriorates due to sensor sensitivity variations and thermal effects

Engineering Contradiction:

Improvedetection coverageVSAvoidposition detection accuracy

Core Design Contradiction:

Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent merges the function of multiple sensors into a single sensor by using beam splitting optics. Instead of using two separate sensors that suffer from sensitivity variations and thermal drift, the invention splits the laser beam into multiple paths and directs them to a single sensor, combining the detection functions while eliminating the problems of multi-sensor systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the laser beam into multiple separate beams using beam splitters, then guides each segmented beam through different optical paths to a single detection point. This segmentation allows the system to obtain multiple measurement references from a single sensor, improving accuracy without requiring multiple physical sensors.

Inventive Principle:

Principle #1Segmentation

2Difficulty of detecting and measuring

If multiple sensors are positioned on the optical axis, then optical axis detection capability is improved, but device complexity increases due to multiple actuators and rotation mechanisms

Engineering Contradiction:

Improveoptical axis detection capabilityVSAvoidnumber of actuators and rotation mechanisms

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The patent combines multiple detection functions into a single sensor platform. By using beam splitting and optical path guidance, the system achieves the capability of multiple sensors while physically using only one sensor, thereby eliminating the need for multiple actuators and rotation mechanisms associated with each sensor.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces beam splitters and optical guides as intermediary elements between the laser source and the single sensor. These intermediaries redirect and split the light paths, enabling a single sensor to perform the detection functions that would otherwise require multiple sensors and their associated actuation mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If different optical path lengths are used for split light beams, then angular deviation calculation accuracy is improved, but thermal effects cause measurement errors

Engineering Contradiction:

Improveangular deviation calculation accuracyVSAvoidmeasurement stability under thermal effects

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent segments the laser beam into multiple paths with different lengths, allowing the system to calculate both angular and positional deviations through mathematical relationships. By analyzing the differential positions of the split beams, the system can derive accurate angular information while using the same physical sensor platform.

Inventive Principle:

Principle #1Segmentation

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 solution enables accurate detection of optical axis position information and reduces measurement errors, leading to stable and precise correction of the laser light's optical axis.

Implementation Method 1

a light guide unit configured to guide the plurality of split light beams to the detection unit with optical path lengths different from each other

Methodology Applied

Scientific EffectOptical path length difference:

Data Source

PatentUS12332044B2Detection device, correction device, processing device, and article manufacturing method

Publication Date: 2025.06.17 CANON KK

AI summary

Provided is a detection device which is able to accurately detect position information on an optical axis of laser light and reduce a measurement error, including a first split unit configured to split laser light output from a light source into a plurality of light beams, a detection unit configured to detect a position of each of the plurality of light beams, a light guide unit configured to guide the plurality of split light beams to the detection unit with optical path lengths different from each other, and a control unit configured to calculate an angular deviation or a positional deviation of the laser light on the basis of a difference in the position of each of the plurality of light beams detected by the detection unit, wherein the detection unit is one sensor that detects the position of each of the plurality of light beams guided by the light guide unit.