Rotary Deflector Positioning for Optical Beam Scanning Error Reduction
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Solution Overview
Problem
Existing optical beam scanning devices using rotary deflectors, such as polygon mirrors, suffer from significant attachment errors that negatively impact optical characteristics, particularly wave aberration and beam diameter, due to errors in rotation around axes parallel to the main scanning direction.
Innovation Solution
The optical beam scanning device incorporates a rotary deflector that scans a light flux in the main scanning direction, supported by a rotatable support part and positioned by contact with multiple points, where the shortest distance between these points in the optical axis direction is longer than in the main scanning direction, minimizing attachment errors and improving optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotary deflector is used to scan light flux in the main scanning direction, then scanning functionality is achieved, but attachment errors cause rotation around axes parallel to the main scanning direction, leading to increased beam diameter and degraded beam profile
Solution Approach 1:
The patent replaces mechanical attachment positioning with an optical positioning system. Instead of relying on mechanical precision to align the rotary deflector, the system uses optical elements (collimating lens, imaging lens) to define and control the optical axis, making the attachment less sensitive to mechanical alignment errors. The optical system compensates for mechanical imperfections by using optical paths that are less sensitive to angular deviations.
Solution Approach 2:
The patent changes the critical parameter from mechanical alignment precision to optical path geometry. By designing the optical system with specific geometric relationships (collimating lens focal length, imaging lens focal length, and their ratio), the system achieves insensitivity to attachment errors. The optical parameters are designed such that small angular deviations in mechanical attachment do not translate to significant beam diameter changes or profile degradation.
2Manufacturing precision
If the rotary deflector is positioned with high precision, then wave aberration is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent eliminates complex mechanical positioning mechanisms by using an optical positioning approach. Instead of adding precision mechanical adjustment mechanisms, the system uses optical elements to define the optical axis and make the system insensitive to mechanical positioning errors. This reduces device complexity while maintaining or improving positioning precision.
Solution Approach 2:
The optical system performs self-alignment through its geometric design. The collimating lens and imaging lens are positioned at specific locations relative to the rotary deflector, creating an optical path that automatically compensates for mechanical attachment variations. The system self-corrects positioning errors through its optical geometry rather than requiring complex mechanical adjustment mechanisms.
3Manufacturing precision
If attachment errors are suppressed by improving positioning, then optical characteristics improve, but the device size increases
Solution Approach 1:
The patent reduces device size by replacing mechanical positioning solutions with an optical approach. The optical system achieves error suppression through geometric design rather than requiring larger mechanical adjustment mechanisms. The collimating lens and imaging lens are integrated into a compact arrangement that maintains optical performance while minimizing overall device volume.
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 effectively reduces the influence of attachment errors on wave aberration and beam diameter, enhancing the optical performance and allowing for miniaturization of the device while maintaining high image quality.
Implementation Method 1
a rotary deflector that deflects a light flux from a light source and scans it in a main scanning direction
Implementation Method 2
an imaging optical system that images the light flux scanned by the rotary deflector onto a scanning object
Data Source
AI summary
A technique is provided which can improve optical characteristics by suppressing the occurrence of an error in attachment of a rotary deflector that deflects a light flux from a light source and scans it in a main scanning direction. There are provided a rotary deflector that deflects the light flux from the light source and scans it in the main scanning direction, an imaging optical system that images the light flux scanned by the rotary deflector onto a specified scanning object, a support part that supports the rotary deflector rotatably, and a positioning part that comes in contact with the support part at plural contact positions and positions the support part, in which a shortest distance between the plural contact positions in an optical axis direction of the imaging optical system is longer than a shortest distance between the plural contact positions in the main scanning direction.