Laser Scanner Optical Axis Alignment for Parallax Reduction
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Solution Overview
Problem
Existing laser scanning devices face challenges in optimizing space utilization and minimizing parallax errors while maintaining balanced and efficient operation, particularly in incorporating color information and near-field correction.
Innovation Solution
The design incorporates a central mirror between the receiver lens and rear mirror for improved focusing and space utilization, with a color camera aligned on the optical axis to reduce parallax, and a hybrid rotor structure using a metallic holder, coated glass rotary mirror, and plastic housing for balance and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional optical path arrangement is used with light receiver positioned after the receiver lens, then the optical path is simple, but the space utilization is poor and parallax errors occur
Solution Approach 1:
The patent positions the light receiver on the optical axis of the receiver lens, utilizing the axial dimension rather than the lateral dimension. This dimensional repositioning allows the receiver to capture light without being laterally offset, thereby eliminating parallax errors while improving space utilization within the compact scanner housing.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical element that directs the reflected light beam from the rotary mirror to the light receiver positioned on the optical axis. This intermediary component enables the complex optical path required for improved space utilization and parallax elimination without requiring direct lateral positioning of the receiver.
2Measurement precision
If the light receiver is positioned laterally offset from the optical axis, then the optical path is straightforward, but parallax errors are introduced in the measurements
Solution Approach 1:
The patent eliminates parallax errors by repositioning the light receiver from a lateral offset position to a position on the optical axis. This dimensional change ensures that the receiver captures light exactly along the optical path, eliminating the geometric source of parallax errors while the beam splitter manages the optical routing to maintain compactness.
Solution Approach 2:
The beam splitter serves as an intermediary that enables the light receiver to be positioned on the optical axis (improving measurement precision) while still receiving the reflected light beam through optical redirection. This intermediary component resolves the conflict between precise axial positioning and compact device design.
3Length of stationary object
If a long focal length is used for the receiver lens, then the measurement range is increased, but the device size increases
Solution Approach 1:
The patent utilizes the optical axis dimension to position the light receiver, allowing the use of a receiver lens with adequate focal length for measurement range while keeping the device compact. The axial positioning and beam splitting arrangement enable efficient use of the focal length without requiring excessive lateral or longitudinal device dimensions.
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 enhances space efficiency, reduces parallax errors, and maintains balance and dynamic stability, allowing for increased focal length and effective near-field correction while integrating color information without shadowing effects.
Implementation Method 1
A rotary mirror which rotates and which comprises a polished plate of a metallic rotor, deflects both an emission light beam and a reception light beam
Implementation Method 2
The receiver lens reproduces the reception light beam on a light receiver which is arranged on an optical axis behind the receiver lens
Implementation Method 3
The receiver lens reproduces the reception light beam on a light receiver
Implementation Method 4
a central mirror is provided between the receiver lens and the rear mirror, where the central mirror reflects the reception light beam towards the rear mirror
Implementation Method 5
a rear mirror, which reflects the reception light beam that has been refracted by the receiver lens towards the receiver lens
Implementation Method 6
an emission mirror in front of the color camera is provided, where the emission mirror is reflecting for the emission light beam
Data Source
AI summary
In a device for optically scanning and measuring an environment, where the device is a laser scanner having a light emitter which, by a rotary mirror, emits an emission light beam, with a light receiver which receives a reception light beam, which, after passing the rotary mirror and a receiver lens which has an optical axis, is reflected from an object in the environment of the laser scanner. The laser scanner also includes a control and evaluation unit which, for a multitude of measuring points, determines the distance to the object. Also, a rear mirror is provided on the optical axis behind the receiver lens, where the rear mirror reflects towards the receiver lens the reception light beam which is refracted by the receiver lens.