Optical Device Column Parts Stray Light Molding

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Solution Overview

Problem

The existing light shielding members in optical devices face molding failure when the distance between through-holes is reduced to minimize stray light, as the resin material's fluidity is compromised, leading to poor optical performance.

Innovation Solution

An optical device with a lens member and column parts where the optical axes are parallel, and the column parts are integrally formed to allow light to pass through while preventing stray light, with a structure that maintains material fluidity and prevents molding failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the distance between through-holes in the light shielding member is reduced to minimize stray light, then stray light is reduced, but molding failure occurs due to compromised resin material fluidity

Engineering Contradiction:

Improvestray lightVSAvoidmolding failure

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The light shielding member is segmented into multiple column parts, each corresponding to a lens position. This segmentation allows the through-holes to be positioned closer together without compromising the overall structural integrity during molding, as each column part acts as an independent light transmission channel while the spaces between them provide necessary material continuity for molding

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The column parts have different light transmission properties at different locations: the inner peripheral surfaces are configured to allow light passage while the outer surfaces block stray light. This local differentiation enables precise control of light paths without requiring excessive spacing between through-holes, maintaining both optical performance and molding reliability

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the distance between lenses in the lens member is reduced to improve optical density, then optical performance is improved, but the distance between through-holes must also be reduced causing molding failure

Engineering Contradiction:

Improveoptical densityVSAvoidmolding failure

Core Design Contradiction:

Area of stationary objectVSEase of manufacture

Solution Approach 1:

The solution addresses the two-dimensional spacing problem by introducing vertical dimensionality through the column part structure. The column parts extend vertically with specific height configurations that allow light to pass through while the horizontal spacing can be minimized. This dimensional approach enables reduced lens spacing without proportionally reducing through-hole spacing, avoiding molding failures

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Use of energy by moving object

If through-holes are formed in a light shielding member to allow light passage, then light transmission is enabled, but the structure becomes prone to molding failure when spacing is reduced

Engineering Contradiction:

Improvelight transmissionVSAvoidmolding failure

Core Design Contradiction:

Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

Instead of forming through-holes in a continuous light shielding member (which causes molding issues when spaced closely), the invention inverts the approach by forming column parts that protrude from the light shielding member. The column parts themselves define the light transmission paths, while the spaces between them provide the necessary material continuity for successful molding, effectively reversing the traditional through-hole concept

Inventive Principle:

Principle #13The other way round (Inversion)

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 solution effectively reduces stray light and maintains optical performance by preventing molding failures, ensuring consistent light transmission and improved focal depth without compromising the resin's fluidity during manufacturing.

Implementation Method 1

each allow light to pass through inside

Methodology Applied

Scientific EffectLight transmission: Light

Implementation Method 2

light is less likely to pass from inside to outside the column part than through an end portion of the column part

Methodology Applied

Scientific EffectStray light blocking: Absorption (EM radiation)

Data Source

PatentUS11073640B2Optical device, image reading device, and image forming apparatus

Publication Date: 2021.07.27 FUJIFILM BUSINESS INNOVATION CORP

AI summary

An optical device includes: a lens member including a plurality of lenses arranged such that optical axes of the lenses are substantially parallel to one another; and a plurality of column parts that are each provided along the optical axis of each lens among the plurality of lenses and each allow light to pass through inside, each column part having an outer periphery through which light is less likely to pass from inside to outside the column part than through an end portion of the column part in a direction along the optical axis, the plurality of column parts being integrally formed and disposed to face the lens member.