Annular Inclined Surface Lens Edge for Ghosting Suppression

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Solution Overview

Problem

In optical lens units for small imaging devices, the alignment of conical surfaces for axis alignment makes it difficult to position shading plates effectively, leading to unwanted light reflection and ghosting/flare issues due to the lack of reference points outside conical surfaces for placing shading plates, resulting in non-shading portions that allow unwanted light to reach the image sensor.

Innovation Solution

The optical lens design incorporates an annular inclined surface on the edge portions of the lenses to reflect unwanted light toward an object, rather than allowing it to reach the image sensor, with the inclined surface formed between the lens portion and conical surface or surrounding the lens portion, effectively blocking or redirecting light that would cause ghosting and flare.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conical surfaces are used for optical axis alignment between lenses, then alignment precision is improved, but it becomes difficult to position shading plates effectively outside the conical surfaces

Engineering Contradiction:

Improveoptical axis alignment precisionVSAvoidshading plate positioning

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The edge portion of the lens is divided into functionally distinct zones: the conical surface for optical axis alignment and the annular inclined surface for shading plate positioning. This segmentation allows each surface to serve its specific purpose without interfering with the other, resolving the contradiction between alignment precision and shading plate placement ease

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The solution moves the shading plate positioning function from the radial dimension (conical surface) to the axial dimension by introducing the annular inclined surface. This dimensional transition provides a new reference plane for shading plate placement that does not conflict with the conical surface alignment function

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Object-affected harmful factors

If shading plates are disposed between lenses to block unwanted light, then ghosting and flare are reduced, but positioning references outside conical surfaces are lacking

Engineering Contradiction:

Improveghosting and flareVSAvoidpositioning reference structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The edge portion of the lens is designed to serve multiple functions: the conical surface provides optical axis alignment while the annular inclined surface provides shading plate positioning references. This multi-functionality eliminates the need for separate positioning structures, reducing device complexity while maintaining effective shading plate placement to prevent ghosting and flare

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The lens structure itself provides the positioning reference for the shading plate through the annular inclined surface, eliminating the need for external or additional positioning structures. The lens serves its own shading plate positioning needs, simplifying the overall device structure while maintaining effective unwanted light blocking

Inventive Principle:

Principle #25Self-service

3Reliability

If light is totally reflected by the concave surface, then light control is improved, but unwanted light reaches the image sensor causing ghosting and flare

Engineering Contradiction:

Improvelight controlVSAvoidunwanted light reflection

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The annular inclined surface converts the harmful totally reflected light into a beneficial outcome by redirecting it away from the image sensor. The same optical properties that enable light control (total internal reflection) are harnessed to redirect unwanted light to harmless paths, turning the potential harm into a solution for ghosting and flare prevention

Inventive Principle:

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

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 design reduces unwanted light reflection on the image sensor by redirecting at least 70% of light totally reflected by the concave surface toward an area other than the imaging area, significantly suppressing ghosting and flare.

Implementation Method 1

The inclined surface reflects, toward an object, light traveling toward the edge portion after reflected by the lens portion

Methodology Applied

Scientific EffectLight reflection: Reflection

Data Source

PatentUS8780461B2Optical lens and lens unit using the same

Publication Date: 2014.07.15 TOKYO VISIONARY OPTICS CO LTD

AI summary

An annular inclined surface is formed on an edge portion of a first plastic lens in such a manner that the inclined surface surrounds a concave surface formed in a second surface of the first plastic lens. The inclined surface reflects unwanted light reflected by the concave surface so as to prevent the unwanted light from passing through the non-shading portion of the edge portion outside the effective area of a lens portion and then being reflected on an imaging area. This can suppress ghosting and flare due to the reflection of the unwanted light on the imaging surface.