Multilayer Ceramic Capacitor Structure for Acoustic Noise Reduction
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Solution Overview
Problem
Multilayer ceramic capacitors experience acoustic noise due to vibration transmission when mounted on substrates, and existing methods to suppress this noise are ineffective when the capacitor is mounted upside down, leading to insufficient strength and peeling issues between differently colored outer layers.
Innovation Solution
A multilayer ceramic capacitor design with a thicker lower outer layer portion than the upper outer layer portion, combined with a side gap portion made of the same material as the dielectric layer and including Mg as a sintering aid, ensures correct mounting direction and sufficient strength by visually distinguishing the internal electrode layers and using a conductive resin layer for shock absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If different materials are used for the lower outer layer portion and the upper outer layer portion to indicate mounting direction, then mounting direction recognition is improved, but peeling occurs between layers and strength is insufficient
Solution Approach 1:
The patent applies local quality by making the lower outer layer portion thicker than the upper outer layer portion, creating a local structural difference that indicates mounting direction without changing material composition. This thickness variation provides visual and tactile direction recognition while maintaining uniform material properties throughout all outer layers to prevent peeling and ensure sufficient bonding strength.
2Object-affected harmful factors
If the upper outer layer portion is made thicker to suppress vibration transmission when mounted upside down, then acoustic noise is reduced, but the overall device size increases
Solution Approach 1:
The patent applies asymmetry by making the lower outer layer portion thicker than the upper outer layer portion. This asymmetric thickness distribution ensures that when the capacitor is mounted in the correct orientation, the thicker lower layer effectively suppresses vibration transmission to the substrate, reducing acoustic noise. The asymmetry is designed within acceptable volume constraints to achieve noise suppression without excessive size increase.
3Ease of operation
If the side gap portion thickness is reduced to improve mounting direction recognition, then visual distinction is enhanced, but mechanical strength may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the side gap portion thickness to about 15 μm or less, which provides sufficient visual distinction for mounting direction recognition while maintaining adequate mechanical strength through precise parameter control. This thickness parameter is carefully selected to balance the competing requirements of visibility and structural integrity.
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
Facilitates correct mounting direction and reduces acoustic noise by ensuring the thicker lower outer layer is always on top, preventing peeling and enhancing the capacitor's reliability and insulating properties.
Implementation Method 1
stress and mechanical strain cause vibration, which is then transmitted to a substrate on which the multilayer ceramic capacitor is mounted
Implementation Method 2
the entire substrate functions as an acoustic reflecting surface, and 'acoustic noise', which is a vibration sound, is generated
Implementation Method 3
stress and mechanical strain occur when an electric field is applied
Implementation Method 4
stress and mechanical strain occur when an electric field is applied
Implementation Method 5
since the dielectric layers have piezoelectric and electrostrictive properties, stress and mechanical strain occur when an electric field is applied
Implementation Method 6
since the dielectric layers have piezoelectric and electrostrictive properties, stress and mechanical strain occur when an electric field is applied
Implementation Method 7
using a conductive resin layer for shock absorption
Implementation Method 8
a side gap portion made of the same material as the dielectric layer and including Mg as a sintering aid
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body and external electrodes. The multilayer body includes an inner layer portion including dielectric layers and internal electrode layers alternately stacked, and first and second outer layer portions on opposite sides of the inner layer portion in a stacking direction, side gap portions on opposite sides in a width direction, main surfaces on opposite sides in the stacking direction, side surfaces on opposite sides in the width direction, and end surfaces on opposite sides in a length direction. Each external electrode is provided at one end surfaces of the multilayer body, and extends from the end surface to a portion of the main surface. A difference in location between ends at the side surface of two adjacent internal electrode layers is about 0.5 μm or less. The second outer layer portion is thicker than the first outer layer portion.