Vibration Node Relocation in Dome Cover Water Removal

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Solution Overview

Problem

Existing vibration devices for removing water droplets or dust from dome-shaped covers in camera modules fail to reliably eliminate these contaminants due to vibration nodes appearing within the camera's field of view, which limits the effectiveness of the removal process.

Innovation Solution

A vibration device comprising a dome-shaped cover, a tubular support body, and a vibrating body, where the cover and support body are vibrated at the same or substantially the same resonant frequency, with the drive circuit driving the vibrating body to create a vibration mode where displacements on both sides of the connection portion are opposite, ensuring no vibration node is present within the field of view, thus allowing for effective removal of water droplets and dust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dome-shaped light-transmissive body is vibrated by a piezoelectric vibrator, then water droplets can be removed, but a vibration node is generated within the field of view of the camera

Engineering Contradiction:

Improvewater droplet removal effectivenessVSAvoidvibration node in field of view

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional approach by positioning the vibration node at the connection portion between the dome-shaped cover and support body, rather than allowing it to appear anywhere on the dome surface. This is achieved by coupling the piezoelectric vibrator to the support body rather than directly to the dome cover, thereby relocating the harmful node to a position outside the camera's field of view while maintaining effective vibration for droplet removal.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The support body serves as an intermediary element between the piezoelectric vibrator and the dome-shaped cover. The vibrator couples to the support body, which then transmits vibration to the dome cover. This intermediary structure allows the vibration node to form at the connection between the support body and dome cover, keeping it outside the field of view, while still achieving effective vibration transmission for contaminant removal.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If the piezoelectric vibrator is fixed directly to the dome-shaped cover, then vibration is applied directly to the cover, but the vibration node appears on the dome surface within the camera's field of view

Engineering Contradiction:

Improvevibration transmission speedVSAvoidvibration node on dome surface

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The support body acts as an intermediary structure that couples the piezoelectric vibrator to the dome-shaped cover. This intermediary allows vibration to be transmitted effectively to the cover while positioning the vibration node at the connection portion between the support body and dome cover, rather than on the dome surface itself, thereby eliminating the harmful node from the camera's field of view.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of fixing the vibrator directly to the dome cover as in conventional designs, the patent inverts the coupling arrangement by fixing the vibrator to the support body and having the support body couple to the dome cover. This inversion relocates the vibration node to the support body-dome cover connection, keeping it outside the field of view while maintaining effective vibration transmission.

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

This configuration ensures that water droplets and dust are reliably removed from the dome-shaped cover without creating a vibration node within the camera's field of view, enhancing the camera's operational reliability and image quality.

Implementation Method 1

a piezoelectric vibrator is fixed to the hood. Water droplets adhering to an outer surface of the hood are atomized and removed by vibration of the piezoelectric vibrator

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the drive circuit driving the vibrating body at the same or substantially the same frequency as the resonant frequency to vibrate the cover and the support body

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

Water droplets adhering to an outer surface of the hood are atomized and removed by vibration of the piezoelectric vibrator

Methodology Applied

Scientific EffectMechanical vibration: Vibration

Data Source

PatentUS11503190B2Vibration device and optical detection device

Publication Date: 2022.11.15 MURATA MFG CO LTD

AI summary

A vibration device includes a light-transmissive body defining a cover that includes a detection region of an imaging element as an optical detection element, a tubular support body which includes an interior space that includes the imaging element and is connected to the light-transmissive body, a vibrating body which is coupled to the support body and vibrates the light-transmissive body with the support body provided therebetween, and a drive circuit which drives the vibrating body.