Capacitor Electrode Thickness Ratios for Acoustic Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors generate acoustic noise due to distortion when voltage varies, causing vibrations in circuit boards, which is a problem in electronic devices like TVs and mobile phones, and existing solutions do not sufficiently suppress this noise.
Innovation Solution
A capacitor design with specific dimensions and electrode configurations, where the thickness of certain regions relative to each other and to the overall capacitor body is optimized to reduce acoustic noise, including a condition where t2/t1 > 0.07 and t3/t1 > 0.07, with t2 and t3 being greater than w2 and w3, and t2 and t3 being equal or substantially equal, to minimize distortion and noise transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the capacitor uses a conventional design with uniform electrode distribution, then the manufacturing process is simple, but acoustic noise is generated due to distortion when voltage varies
Solution Approach 1:
The patent applies local quality by creating an asymmetric electrode configuration where the first electrode extends further in the thickness direction than the second electrode. This local structural variation in the capacitor body reduces distortion and acoustic noise generation while maintaining overall manufacturing feasibility through a controlled deviation from uniform symmetry.
Solution Approach 2:
The patent directly implements asymmetry by designing the capacitor with non-uniform electrode distribution where the first inner electrode and second inner electrode have different extension lengths in the thickness direction. This asymmetric structure creates uneven stress distribution that counteracts distortion effects and reduces acoustic noise during voltage variations.
2Object-affected harmful factors
If the capacitor structure is optimized to reduce distortion, then acoustic noise is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying a particular thickness ratio relationship between the first electrode extension (t2) and the second electrode extension (t3) in the thickness direction. By controlling this geometric parameter ratio, the design achieves optimal distortion reduction while providing clear manufacturing specifications that balance precision requirements with manufacturability.
3Reliability
If the capacitor reduces acoustic noise through structural optimization, then the stability and reliability improve, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the capacitor body into distinct functional regions: a first region containing the first inner electrode, a second region containing the second inner electrode, and a third region that is the intersection of both electrode extensions. This segmented view of the capacitor structure helps manage the complexity by organizing the asymmetric design into manageable, functionally-defined zones while achieving improved reliability through reduced distortion.
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
Significantly reduces or prevents acoustic noise in capacitor mounting structures by optimizing the thickness ratios of the capacitor's regions, improving the stability and reliability of the capacitors and reducing noise levels by up to 9.1 dB compared to conventional designs.
Implementation Method 1
The ceramic section includes ferroelectric ceramics
Implementation Method 2
When a voltage applied to a multilayer ceramic capacitor varies, the multilayer ceramic capacitor is distorted in some cases. The distortion of the multilayer ceramic capacitor is transferred to a circuit board on which the multilayer ceramic capacitor is mounted, via a bonding material. This causes the circuit board to vibrate.
Data Source
AI summary
In a capacitor main body, a dimension along the thickness direction of a first region where a first inner electrode and a second inner electrode are provided is t1, a dimension along the thickness direction of a second region that is positioned on the side of a first main surface relative to the first region is t2, and a dimension along the thickness direction of a third region that is positioned on the side of a second main surface relative to the first region is t3. A condition of t2/t1>about 0.15 and a condition of t3/t1>about 0.15 are satisfied.