Light Scanning Device Polarization Control for Uniform Illumination

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Solution Overview

Problem

The existing light scanning devices with linearly polarized light fluxes experience unbalanced incident light quantity distribution due to changes in polarization direction and reflectivity when using multibeam light-emitting elements, leading to inefficiencies in image formation.

Innovation Solution

A light scanning device is designed with a deflecting part and reflective mirrors, where the polarization direction of light fluxes is set to optimize reflectivity across different deflection ranges, ensuring uniform incident light distribution by adjusting the rotation of light-emitting elements and the arrangement of light-emitting points.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a light-emitting element with multibeam emits linearly polarized light fluxes and is rotated to adjust incident intervals, then the incident intervals of light fluxes on the photosensitive body surface are adjusted, but the polarization direction changes and the ratio of P polarized components increases, causing unbalanced incident light quantity distribution

Engineering Contradiction:

Improveadjustment of incident intervalsVSAvoiduniformity of incident light quantity distribution

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the polarization direction parameter of the light fluxes by rotating the light-emitting element in a specific direction (different from conventional approaches). This parameter change is designed to compensate for the reflectivity variations at different angles, thereby maintaining uniform incident light quantity distribution while still achieving adjustable incident intervals through the rotation.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If the polarization direction of light fluxes is changed by rotating the light-emitting element, then the ratio of P polarized components increases, but the reflectivity of each light flux changes significantly, further increasing unbalance of incident light quantity distribution

Engineering Contradiction:

Improveadjustability of light flux configurationVSAvoiduniformity of incident light quantity distribution

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent converts the harmful effect of increased P polarized components into a beneficial outcome. By carefully controlling the rotation direction and angle of the light-emitting element, the increase in P polarized components is harnessed to compensate for the natural reflectivity variations at different angles, ultimately achieving more uniform light distribution rather than worsening it.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If conventional light scanning devices use linearly polarized light fluxes with multibeam, then the light flux can be emitted from a single element, but the reflectivity of P polarization changes significantly according to angle of incidence and reflection, causing unbalanced incident light quantity distribution

Engineering Contradiction:

Improvenumber of light-emitting elementsVSAvoiduniformity of incident light quantity distribution

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent introduces dynamic adjustment through rotation of the light-emitting element to compensate for the static reflectivity variations caused by different angles of incidence. This dynamic approach allows the system to maintain uniform light distribution across the photosensitive body surface while using a single light-emitting element, thereby reducing device complexity.

Inventive Principle:

Principle #15Dynamics

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 balances reflectance distributions at the deflecting and reflective mirrors, resulting in uniform incident light quantity distributions on the scan object surface, enhancing the efficiency of image formation.

Implementation Method 1

The polygonal mirror and the plurality of reflective mirrors reflect the light flux

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

The light-emitting element emits a light flux

Methodology Applied

Scientific EffectLight: Light

Implementation Method 3

if a light flux emitted from the light-emitting element is linearly polarized light, the light flux may contain many P polarized components with respect to the reflecting surfaces

Methodology Applied

Scientific EffectPolarization: Polarisation

Implementation Method 4

The plurality of lenses deflect the light flux

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS9116458B2Light scanning device and image forming apparatus

Publication Date: 2015.08.25 SHARP KK

AI summary

A light scanning device of the invention includes a scan deflection range of each of the light fluxes deflected by the deflecting part in a scan period of the scan object with the respective light fluxes is divided into a first deflection range where a reflection angle of each of the light fluxes with respect to the deflecting part is small and a second deflection range where the reflection angle is large. A polarization direction of each of the light fluxes is set such that a reflectivity of the reflective mirror when each of the light fluxes deflected in the second deflection range is reflected becomes larger than a reflectivity of the reflective mirror when each of the light fluxes deflected in the first deflection range is reflected.