Rotatable Polygon Mirror With Phase-Shifted Through-Hole for Heat Control
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Solution Overview
Problem
Conventional rotatable polygon mirrors in optical deflectors experience thermal deformation due to heat accumulation from the rotor, leading to mechanical accuracy issues and a decline in optical performance and image quality.
Innovation Solution
A rotatable polygon mirror design featuring a through hole that engages with the rotational shaft, with a shape similar to the polygonal shape of the mirror surfaces, and phase-shifted vertexes to reduce thermal conduction and deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rotatable polygon mirror is driven by the rotor, then the optical deflector can perform scanning function, but heat accumulates in the inside space surrounded by the rotatable polygon mirror, causing thermal deformation
Solution Approach 1:
The patent extracts the harmful heat from the system by providing a through-hole that penetrates the rotatable polygon mirror, allowing heat to escape from the enclosed inside space. This prevents heat accumulation while maintaining the scanning function.
Solution Approach 2:
The patent applies different thermal properties to different parts of the rotatable polygon mirror. The through-hole creates a localized heat dissipation path, while the reflecting surfaces maintain their optical properties. The phase-shifted positioning optimizes heat distribution to prevent localized thermal deformation.
2Stability of the object's composition
If all sides of the rotational shaft contact the rotor for stable rotation, then mechanical stability is improved, but heat is easily transmitted to the rotatable polygon mirror via the rotor
Solution Approach 1:
The through-hole acts as an intermediary structure that decouples the thermal path from the rotational support function. It allows the rotational shaft to maintain contact for stability while preventing direct heat transmission to the mirror body.
Solution Approach 2:
The patent uses asymmetric positioning of the through-hole relative to the rotational shaft contact points. This creates an optimized thermal barrier while maintaining mechanical stability, as the heat transmission path is disrupted at specific locations without compromising rotational support.
3Manufacturing precision
If the reflecting surfaces and bottom surface of the rotatable polygon mirror are deformed by thermal expansion, then mechanical accuracy deteriorates, but optical performance and image quality decline
Solution Approach 1:
The patent implements preliminary thermal management by providing the through-hole structure before operation. This prevents thermal deformation from occurring in the first place, rather than attempting to correct it after deformation occurs. The phase-shifted positioning is pre-calculated to optimize heat distribution.
Solution Approach 2:
The patent changes the thermal parameters of the rotatable polygon mirror by introducing the through-hole, which fundamentally alters the heat distribution pattern. This prevents thermal expansion-induced deformation and maintains both mechanical accuracy and optical performance.
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 design effectively reduces thermal deformation of the rotatable polygon mirror, maintaining mechanical accuracy and improving optical performance and image quality.
Implementation Method 1
heat from the rotor accumulates in an inside space surrounded by the rotatable polygon mirror of concave shape during a driving of the optical deflector, which may increase a temperature of the rotatable polygon mirror. Furthermore, because all sides of the rotational shaft in a circumferential direction contact, that is to say, surface contact the rotor, a configuration of the bottom surface of concave shape of the rotatable polygon mirror is such that heat is easily transmitted to the rotatable polygon mirror via the rotor
Implementation Method 2
a plurality of reflecting surfaces provided in parallel to a rotational axis direction and configured to reflect light
Data Source
AI summary
A rotatable polygon mirror includes a plurality of reflecting surfaces provided in parallel to a rotational axis direction, first surface and second surface of polygonal shape perpendicular to the plurality of reflecting surface and of which each side is continued to the plurality of reflecting surfaces. The second surface is opposite to the first surface. A through hole penetrates though the first and second surfaces in parallel to the rotational axis direction and to engage with a rotational shaft of a driving portion. As seen in the rotational axis direction, the through hole has substantially similar shape to the polygonal shape of the first and the second surfaces, and vertexes of the similar shape of the through hole are different in phase from apexes of the polygonal shape of the first and second surfaces with respect to a rotational direction of the polygon mirror.