Dielectric Composition for High Voltage Capacitors
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Solution Overview
Problem
Conventional dielectric compositions used in medium- and high-voltage capacitors experience a reduction in dielectric constant and capacitance when subjected to high DC biases, particularly in laminated ceramic capacitors with thin layers, failing to meet the demands of miniaturization and increased capacity requirements.
Innovation Solution
A dielectric composition with a main component of (Bi a Na b Sr c Ln d ) TiO 3, where Ln is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, or Yb, and a, b, c, and d are within specific mole ratio ranges, enhancing the dielectric constant and withstand field when a DC bias of 8 V/µm is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional dielectric compositions are used in laminated ceramic capacitors with thin layers, then miniaturization and increased capacity are achieved, but the dielectric constant and capacitance are reduced when high DC bias is applied
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric material by incorporating specific amounts of bismuth oxide (0.1-5 wt%), sodium oxide (0.1-5 wt%), strontium oxide (0.1-5 wt%), and lanthanide oxides (0.01-1 wt%) into the barium titanate base composition. This compositional parameter change enables the material to maintain high dielectric constant (≥800) and capacitance even when subjected to high DC bias voltages (≥8 V/μm), resolving the contradiction between miniaturization and dielectric performance under bias
Solution Approach 2:
The patent creates a composite dielectric material by combining barium titanate with multiple oxide components including bismuth oxide, sodium oxide, strontium oxide, and various lanthanide oxides (such as europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, and ytterbium oxide). This composite structure synergistically enhances the dielectric properties, allowing the material to maintain stable dielectric constant and capacitance under high DC bias conditions while enabling thinner layer designs
2Volume of moving object
If the dielectric layer thickness is reduced for miniaturization, then component size is reduced, but the withstand field decreases under high DC bias
Solution Approach 1:
The patent modifies the material composition parameters to include specific ranges of bismuth oxide (0.1-5 wt%), sodium oxide (0.1-5 wt%), strontium oxide (0.1-5 wt%), and lanthanide oxides (0.01-1 wt%). These parameter changes enhance the material's intrinsic breakdown strength, enabling the dielectric layer to withstand high electric fields (≥14 V/μm) even when the layer thickness is reduced for miniaturization purposes
Solution Approach 2:
The composite dielectric system combining barium titanate with multiple oxide additives creates a material with enhanced structural and electrical properties. The synergistic interaction between components improves the material's resistance to electrical breakdown, allowing thinner dielectric layers to achieve the required withstand field strength for high-voltage applications
3Ease of manufacture
If conventional dielectric compositions are used, then manufacturing is simpler, but the dielectric constant drops significantly when DC bias exceeds 5 V/μm
Solution Approach 1:
The patent specifies precise compositional parameters: bismuth oxide (0.1-5 wt%), sodium oxide (0.1-5 wt%), strontium oxide (0.1-5 wt%), and lanthanide oxides (0.01-1 wt%). These parameter specifications provide clear manufacturing targets that balance ease of production with superior dielectric performance under high DC bias, maintaining dielectric constant ≥800 even when bias exceeds 5 V/μm
Solution Approach 2:
The patent introduces trace amounts of lanthanide oxides (0.01-1 wt%) as localized dopants within the dielectric matrix. These localized compositional modifications create specific regions with enhanced dielectric properties that stabilize the overall material performance under high electric fields, while the bulk composition remains relatively simple for manufacturing
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 dielectric composition achieves a high dielectric constant of 800 or greater and a withstand field of 14 V/µm or greater when a DC bias of 8 V/µm is applied, effectively addressing the limitations of conventional compositions and supporting high-voltage applications without lead contamination.
Implementation Method 1
the dielectric constant and the capacitance are reduced... a dielectric composition which has a relatively high dielectric constant of 800 or greater... achieves a high dielectric constant of 800 or greater
Data Source
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Figure 3
AI summary
The aim of the present invention lies in providing a dielectric composition which has a relatively high dielectric constant of 800 or greater, and which has a withstand field of 14 V/μm or greater when a DC bias of at least 8 V/μm is applied, and also in providing a dielectric element employing said dielectric composition, an electronic component, and a laminated electronic component. A dielectric composition having a main component represented by (BiaNabSrcLnd) TiO3, characterized in that Ln is at least one selected from among: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Yb; and a, b, c and d satisfy the following: 0<a<0.50, 0<b<0.50, 0<c≤0.80, 0<d≤0.20, and 0.90<a+b+c+d≤1.05.