Dielectric Ceramic Composition for Miniaturized Capacitors
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Solution Overview
Problem
Laminated ceramic capacitors face challenges in reducing size while maintaining capacitance and reliability, as thinner dielectric ceramic layers increase electric field strength, leading to decreased withstand voltage and reliability issues under high-temperature and mechanical stress.
Innovation Solution
A dielectric ceramic with a composition of (Ba1-xCax)TiO3, Re2O3, MgO, MnO, V2O5, and SiO2, where 0.045≦x≦0.15 and 0.65≦a≦1.5, 0.15≦b≦2.0, 0.4≦c≦1.5, 0.02≦d≦0.25, and 0.2≦e≦3.0, which allows accessory constituents to diffuse into main grains, reducing residual stress and improving mechanical strength without sacrificing dielectric constant or high-temperature load life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of dielectric ceramic layers is reduced to decrease capacitor size, then the capacitance density increases, but the electric field strength increases leading to decreased withstand voltage and reliability
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric ceramic by incorporating specific amounts of Re2O3 (0.65≤a≤1.5), MgO (0.15≤b≤2.0), MnO (0.4≤c≤1.5), V2O5 (0.02≤d≤0.25), and SiO2 (0.2≤e≤3.0) alongside (Ba1-xCax)TiO3 (0.045≤x≤0.15). This compositional parameter change allows the ceramic to maintain high reliability and withstand voltage even when the dielectric layer thickness is reduced, thus enabling miniaturization without sacrificing reliability.
2Quantity of substance
If the size of ceramic grains is reduced to increase capacitance, then the capacitance increases, but the dielectric constant decreases
Solution Approach 1:
The patent creates a composite dielectric ceramic material by combining (Ba1-xCax)TiO3 as the main constituent with multiple accessory constituents including Re2O3, MgO, MnO, V2O5, and SiO2. This composite material structure allows the ceramic to achieve both high capacitance and high dielectric constant simultaneously, resolving the contradiction between increasing capacitance and maintaining dielectric constant.
3Device complexity
If Re2O3 content is kept low to maintain dielectric constant, then the dielectric constant is maintained, but the mechanical strength and reliability against temperature changes and mechanical shocks decrease
Solution Approach 1:
The patent merges multiple oxide components into a unified dielectric ceramic system, combining Re2O3 with MgO, MnO, V2O5, and SiO2 alongside (Ba1-xCax)TiO3. This combination allows the Re2O3 content to be increased within the specified range (0.65≤a≤1.5) to improve mechanical strength and reliability against temperature changes and mechanical shocks, while the synergistic effect of the composite material maintains the dielectric constant at acceptable levels.
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 ceramic ensures high reliability against temperature changes and mechanical shocks, reducing crack incidence and maintaining dielectric constant and high-temperature load life characteristics, as demonstrated by experimental examples.
Implementation Method 1
it has been confirmed that accessory constituents are likely to diffuse into main grains, residual stress is likely to be reduced, and mechanical strength is likely to be improved
Data Source
AI summary
A laminated ceramic capacitor which has a dielectric ceramic with a high dielectric constant and has excellent reliability against changes in temperature and mechanical shocks, even when dielectric ceramic layers are reduced in thickness employs a dielectric ceramic containing (Ba1-xCax)yTiO3 (where 0.045≦x≦0.15 and 0.98≦y≦1.05) as its main constituent and containing Re2O3 (where Re is at least one of Gd, Dy, Ho, Yb, and Y), MgO, MnO, V2O5, and SiO2 as accessory constituents, which is represented by the general formula: 100(Ba1-xCax)yTiO3+aRe2O3+bMgO+cMnO+dV2O5+eSiO2, and satisfies each of the following conditions: 0.65≦a≦1.5; 0.98≦y≦1.05; 0.15≦b≦2.0; 0.4≦c≦1.5; 0.02≦d≦0.25; and 0.2≦e≦3.0.