Electro-optic Variable Aperture for Compact Camera Modules

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Solution Overview

Problem

Conventional camera modules in portable consumer electronics devices face challenges with fixed optical path apertures due to the complexity and susceptibility to damage of variable apertures, which also increase device thickness, making it difficult to integrate compact camera systems with improved focusing and depth of field.

Innovation Solution

An electro-optic variable aperture using a stack of transparent conductive oxide layers with an electro-chromic medium, allowing for electrical control of light transmission by altering the opacity of the aperture, thereby enabling a compact and shock-resistant camera module with adjustable light admission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional variable apertures using leaflets are used, then aperture adjustment capability is achieved, but device complexity increases and reliability decreases due to susceptibility to physical shock or damage

Engineering Contradiction:

Improveaperture adjustment capabilityVSAvoidresistance to physical shock or damage

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the mechanical leaflet-based aperture system with an electro-optic aperture that uses voltage-controlled transparency changes in a material layer. This eliminates moving parts and mechanical wear, thereby improving reliability and shock resistance while maintaining aperture adjustment capability through electrical control of light transmission.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the optical parameter (transparency) of the aperture material by applying voltage, causing the material to transition between transparent and opaque states. This allows aperture adjustment without mechanical movement, resolving the contradiction between adaptability and reliability.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If conventional variable apertures using leaflets are used, then aperture adjustment capability is achieved, but device thickness increases requiring additional headroom in the z-height direction

Engineering Contradiction:

Improveaperture adjustment capabilityVSAvoiddevice thickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The electro-optic aperture eliminates the need for thick mechanical leaflet structures and actuation mechanisms by using a thin voltage-controlled transparent layer. This substitution dramatically reduces the z-height requirement while preserving aperture adjustment functionality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs a thin film or layer of electro-optic material that can be deposited on a substrate, creating a compact aperture structure with minimal thickness. This thin-film approach enables aperture control without adding significant height to the device.

Inventive Principle:

Principle #30Flexible shells and thin films

3Length of stationary object

If fixed optical path apertures are used, then device thickness is reduced, but adaptability for different focusing and depth of field requirements is lost

Engineering Contradiction:

Improvedevice thicknessVSAvoidfocusing and depth of field control

Core Design Contradiction:

Length of stationary objectVSAdaptability or versatility

Solution Approach 1:

The electro-optic aperture enables dynamic control of the optical parameter (transparency) by applying different voltage levels, allowing the aperture to adjust its effective size and shape. This provides adaptability for different focusing requirements and depth of field control while maintaining a thin profile suitable for portable devices.

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

The electro-optic variable aperture allows for adjustable light control, enhancing focusing and depth of field while maintaining a thin profile, suitable for integration in portable devices without the need for moving parts, thus addressing the limitations of conventional apertures.

Implementation Method 1

The electro-optic aperture may include an electro-chromic (EC) medium that attenuates light from the scene that is passing through the aperture, in response to a voltage being applied to a pair of transparent conductor layers between which the EC medium is sandwiched

Methodology Applied

Scientific EffectElectro-chromic effect: Electrochromism

Data Source

PatentUS9759984B1Adjustable solid film camera aperture

Publication Date: 2017.09.12 APPLE INC

AI summary

A portable electronic device has a device housing, and an electronic camera module in the device housing. The module has a focusing lens to focus light from a scene, an imaging sensor to receive the focused light, and an electro-optic variable aperture to allow different amounts of the light from the scene to reach the imaging sensor. The electro-optic variable aperture may include a first aperture stack placed on a transparent substrate and a second aperture stack placed on the first aperture stack. The first aperture stack defines a first aperture and the second aperture stack defines a second aperture that is larger than the first aperture. Each aperture stack includes a transparent conductive oxide layer that is common with the adjacent aperture stack. Alternatively the electro-optic variable aperture may include an aperture stack that has two transparent conductive oxide layer layers, where one layer is in the form of concentric annuli.