Optical Scanning Apparatus Sub-Scanning Magnification Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Small optical scanning apparatuses face challenges in reducing size while minimizing differences in light amount among scanned surfaces due to varying magnifications in sub-scanning sections, leading to inefficiencies in light use and interference among optical elements.

Innovation Solution

The optical scanning apparatus employs first and second deflecting units and imaging optical systems with specific refractive index and thickness configurations, ensuring that the refractive power in the sub-scanning section is maximized for each imaging element, and the distance from the deflecting unit to the imaging element is optimized to satisfy the condition -d2N2ϕ21ϕ2 < -d1N1ϕ11ϕ1, thereby equalizing sub-scanning magnifications and reducing light differences between scanned surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the optical scanning apparatus is reduced in size, then the apparatus becomes more compact, but the arrangement of optical elements becomes complicated and differences in light amount among scanned surfaces increase

Engineering Contradiction:

Improvesize of optical scanning apparatusVSAvoidarrangement complexity of optical elements

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the refractive powers (φ1, φ2) and distances (d1, d2) of the imaging optical elements to satisfy specific mathematical relationships. This allows the system to maintain uniform sub-scanning magnification across multiple imaging optical systems while keeping the apparatus compact, thereby resolving the contradiction between size reduction and arrangement complexity.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If different layouts are used for imaging optical elements to avoid interference, then spatial interference is reduced, but magnification differences among imaging optical systems increase

Engineering Contradiction:

Improvelayout arrangement of optical elementsVSAvoidmagnification uniformity of imaging optical systems

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent uses parameter changes by establishing specific mathematical relationships between the refractive powers and distances of imaging optical elements. The condition (d1×N1×φ11×φ1) > (d2×N2×φ21×φ2) ensures that sub-scanning magnifications are uniform across different imaging optical systems, even when their layouts differ to avoid spatial interference.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by allowing different imaging optical elements to have different refractive power characteristics and positions tailored to their specific locations and functions. Each element is optimized locally while collectively satisfying the overall magnification uniformity requirement through the mathematical relationship.

Inventive Principle:

Principle #3Local quality

3Device complexity

If magnifications in sub-scanning section are varied among imaging optical systems, then layout flexibility is improved, but light use efficiency decreases

Engineering Contradiction:

Improvelayout flexibility of imaging optical systemsVSAvoidlight use efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by controlling the refractive powers and distances of imaging optical elements to satisfy the condition (d1×N1×φ11×φ1) > (d2×N2×φ21×φ2). This ensures uniform sub-scanning magnification across all imaging optical systems, maximizing light use efficiency while maintaining layout flexibility through the mathematical relationship.

Inventive Principle:

Principle #35Parameter changes

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 allows for a compact optical scanning apparatus with uniform light distribution across scanned surfaces, reducing light differences and enhancing efficiency by adjusting the refractive powers and distances of the imaging elements.

Implementation Method 1

first and second imaging optical systems include first and second imaging elements, respectively, each imaging element having the largest refractive power in a sub-scanning section including an optical axis

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS10754148B2Optical scanning apparatus and image forming apparatus

Publication Date: 2020.08.25 CANON KK

AI summary

An optical scanning apparatus includes first and second deflecting units, and first and second imaging optical systems to guide first and second light fluxes deflected by the first and second deflecting units to first and second scanned surfaces. The first and second imaging optical systems include first and second imaging elements having the largest refractive power in a sub-scanning section. A distance on an optical path between the first deflecting unit and the first imaging element is shorter than that between the second deflecting unit and the second imaging element. The optical scanning apparatus satisfies:-d2N2⁢ϕ21ϕ2<-d1N1⁢ϕ11ϕ1,where N1, d1, ϕ1, and ϕ11 are a refractive index, a thickness on an optical axis, a refractive power in a sub-scanning section, and a refractive power in the sub-scanning section of an incident surface, of the first imaging element, and N2, d2, ϕ2, and ϕ21 are equivalents of the second imaging element.