Lens Unit Shielding for Stray Light in Compact Imaging Devices

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In imaging apparatuses with a light shield body, stray light from light emitters can reflect off the shield or wiring board and enter the lens unit, especially when the distance between the light emitters and the lens unit is minimized for downsizing, leading to image quality issues.

Innovation Solution

The imaging apparatus incorporates a lens unit with blocking parts that project over the region around the lens unit to face the light sources, effectively blocking stray light from entering the lens unit, and utilizes polarization members on these blocking parts to enhance light management and prevent stray light entry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the distance between light emitters and lens unit is shortened to downsize the apparatus, then the apparatus size is reduced, but stray light from light emitters reflects off the light shield body or wiring board and enters the lens unit, degrading image quality

Engineering Contradiction:
Improveapparatus sizeVSAvoidstray light entering lens unit
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The light shield body is divided into multiple light blocking parts, each positioned to block stray light from specific light emitters. This segmentation allows precise control of stray light paths while maintaining a compact overall structure, resolving the contradiction between miniaturization and stray light prevention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light blocking parts act as intermediary elements between the light emitters and the lens unit, intercepting stray light before it can reflect off the wiring board and enter the lens. This intermediary structure enables close positioning of light emitters to the lens while preventing harmful light paths.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a light shield body is disposed around the lens unit to block stray light, then stray light is blocked, but the light shield body occupies space above the light guide body, preventing further downsizing of the apparatus

Engineering Contradiction:
Improvestray light blockingVSAvoidapparatus size
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

Instead of placing a conventional light shield body above the light guide body in the vertical dimension, the light blocking parts are positioned at the periphery of the lens unit, utilizing the radial dimension. This dimensional change allows effective stray light blocking without occupying vertical space that would prevent downsizing.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Light blocking parts are positioned only at specific locations around the lens unit where stray light paths occur, rather than creating a complete shield around the lens. This localized approach blocks harmful light while minimizing the overall volume occupied by the shielding structure.

Inventive Principle:
Principle #3Local quality

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 prevents stray light from entering the lens unit, improving image quality by maintaining a clear optical path and reducing reflections, while maintaining a compact design.

Implementation Method 1

a lens unit (50) that focuses light on the imaging element (91)

Methodology Applied
Scientific EffectLight focusing: Lens

Implementation Method 2

a plurality of light emitters (92) disposed around the lens unit (50)

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 3

a light guide body (60) disposed on an optical path specific to the plurality of light emitters (92)

Methodology Applied
Scientific EffectLight guiding: Optical Fibre

Implementation Method 4

a shield part that projects over a region located around the lens unit and facing the light source so as to block stray light from the light source

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentEP3470917B1Imaging device
Publication Date: 2021.05.12 FUJITSU FRONTECH LTD
  • EP3470917B1 patent drawingFigure 1
  • EP3470917B1 patent drawingFigure 2
  • EP3470917B1 patent drawingFigure 3

AI summary

An imaging apparatus includes an imaging element, a lens unit that focuses light on the imaging element, and a light source disposed around the lens unit. The lens unit includes a blocking part that projects over a region located around the lens unit and facing the light source so as to block stray light from the light source.