Camera Aperture with Piezoelectric Positioning for Light Control

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Solution Overview

Problem

Existing aperture devices in camera modules often experience errors in setting the aperture opening width to the specified value, leading to inappropriate adjustment of light incidence on lenses.

Innovation Solution

An aperture device with a diaphragm plate and a configuration-changing mechanism, including a rotor and moving mechanism, allows precise control of the diaphragm plate's position to accurately set the aperture opening, using a piezoelectric element to rotate the rotor and move the diaphragm plate between aperture and retracted positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two aperture blades are used to adjust the aperture opening, then the amount of light incident on the lens can be controlled, but positional errors occur in the aperture opening width leading to inaccurate light control

Engineering Contradiction:
Improveaperture opening width accuracyVSAvoidlight control accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The aperture device is divided into multiple independent aperture blades (first aperture blade and second aperture blade) that can move independently relative to each other. Each blade has its own driving mechanism, allowing separate control of their positions. This segmentation enables more precise control of the aperture opening width by independently adjusting each blade's position, thereby improving measurement precision and reducing positional errors in the aperture opening width.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If a simple actuator is used to drive aperture blades, then the device structure remains simple, but the precision of aperture position control is insufficient

Engineering Contradiction:
Improveaperture blade position precisionVSAvoidactuator structure complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A movable member is introduced as an intermediary component between the actuator and the aperture blades. The movable member translates the actuator's linear motion into rotational motion that drives both aperture blades simultaneously. This intermediary mechanism enables precise control of aperture blade positions while maintaining a relatively simple overall actuator structure, as the movable member can be designed as a compact mechanical linkage integrated into the actuator assembly.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If aperture blades are made movable to adjust light incidence, then light control flexibility is improved, but shaking of the diaphragm blade occurs due to clearance around the shaft

Engineering Contradiction:
Improvelight control flexibilityVSAvoiddiaphragm blade stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The clearance issue is addressed by extracting and eliminating the problematic rotational shaft mechanism. Instead of rotating aperture blades around a shaft with clearance, the invention uses a movable member that guides the aperture blades along precision linear guides or rails. This removes the source of shaking (shaft clearance) while maintaining the ability to adjust light incidence, thereby improving diaphragm blade stability without sacrificing light control flexibility.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Ensures accurate and appropriate setting of light incidence on the lens, allowing for precise control of image brightness and minimizing positional errors.

Implementation Method 1

using a piezoelectric element to rotate the rotor and move the diaphragm plate between aperture and retracted positions

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4137886B1Aperture apparatus, camera module having aperture apparatus, and electronic device
Publication Date: 2025.08.06 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP4137886B1 patent drawingFigure 1
  • EP4137886B1 patent drawingFigure 2
  • EP4137886B1 patent drawingFigure 3

AI summary

The present disclosure provides an aperture device for setting the amount of light incident on a lens of a camera module. The aperture device includes: a diaphragm plate exhibiting a plate shape and formed with an aperture opening penetrating the diaphragm plate in a plate surface direction; and a configuration-changing mechanism for changing a configuration of the diaphragm plate to an aperture position or a retracted position, the aperture position being a position where the diaphragm plate is on the lens and a center of the aperture opening is configured in a position corresponding to an optical axis of the lens, and the retracted position being a position where the diaphragm plate is retracted from the lens.