LC Resonance Element with Thin-Film Inductor Outside Common Electrode
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Solution Overview
Problem
Conventional LC resonance elements with thin-film capacitors and inductors have complex structures and larger sizes due to separate formation regions and the need for external electrodes, limiting further size reduction and simplification.
Innovation Solution
An LC resonance element with a parallel circuit of thin-film capacitors and inductors, featuring a common electrode on the lower surface, external connection terminals on the upper surface, and a thin-film conductive wire forming the inductor outside the common electrode, which reduces size and simplifies the structure while maintaining high Q values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the inductor and capacitor are formed in totally different regions on the dielectric substrate, then the LC resonance element can be constructed with separate functional regions, but the size of the LC resonance element cannot be further reduced and the structure becomes more complex
Solution Approach 1:
The patent merges the inductor and capacitor into a single integrated structure where the common electrode serves both capacitive functions (forming C1 and C2 with upper electrodes) and the conductive wire forms the inductor. This integration eliminates the need for separate functional regions and through-holes, reducing both device complexity and overall size while maintaining manufacturability through standard thin-film fabrication processes.
2Ease of manufacture
If a through hole is formed in the dielectric substrate to form a parallel circuit, then the inductor and capacitor can be connected, but the structure becomes complicated
Solution Approach 1:
The patent extracts the need for through-holes entirely from the design by forming the parallel circuit connection through the thin-film conductor layer itself. The common electrode and conductive wire are formed in the same thin-film layer, creating the parallel LC circuit without requiring vertical through-hole connections, thereby simplifying the structure and eliminating manufacturing complexity associated with through-hole formation.
3Area of stationary object
If the thin-film inductor overlaps the common electrode in plan view, then the structure is compact, but electrostatic capacitance is formed between the inductor and common electrode causing Q value decrease
Solution Approach 1:
The patent resolves the conflict between compactness and Q-value by transitioning from a planar overlap arrangement to a three-dimensional stacked arrangement. The inductor is positioned in the thin-film conductor layer above the dielectric substrate, while the common electrode is in the lower surface, creating vertical separation that eliminates parasitic capacitance. This dimensional separation maintains compact footprint while preserving high Q-value performance.
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 configuration allows for a compact, simplified LC resonance element with improved reliability and reduced risk of short-circuiting, enabling further size reduction and easier integration into arrays with varying resonance frequencies.
Implementation Method 1
a thin-film capacitor TC including a common electrode 11 formed of a thin-film conductor on a lower surface 12D of the dielectric film 12; a first upper electrode 13A connected to a first external connection terminal 14A; a second upper electrode 13B connected to a second external connection terminal 14B; a first capacitor C1 and a second capacitor C2 that are connected in series via the common electrode 11 and constitute the thin-film capacitor TC
Implementation Method 2
a dielectric film 12 having an upper surface 12U and a lower surface 12D opposite to the upper surface 12D
Implementation Method 3
a thin-film conductive wire 16 that is formed in a region located on the upper surface 12U and outside the common electrode 11 in plan view, constitutes the thin-film inductor TL, and connects the first external connection terminal 14A and the second external connection terminal 14B
Implementation Method 4
an LC resonance element 10 including a parallel circuit PC of a thin-film capacitor TC and a thin-film inductor TL
Data Source
AI summary
An LC resonance element (10) includes a dielectric film (12), a common electrode (11) formed of a thin-film conductor on a lower surface (12D) of the dielectric film, a first capacitor (C1) and a second capacitor (C2) that are connected in series via the common electrode (11) and constitute a thin-film capacitor (TC), first and second external connection terminals (14A, 14B) formed on an upper surface (12U) of the dielectric film, a thin-film conductive wire (16) constituting a thin-film inductor (TL), a first upper electrode (13A) of the first capacitor formed on the upper surface (12U), and a second upper electrode (13B) of the second capacitor formed on the upper surface (12U). The thin-film conductive wire (16) is formed in a region (R2) located on the upper surface (12U) of the dielectric film and outside the common electrode (11) in plan view.