ELASTIC WAVE DEVICE AND FILTER DEVICE
First Claim
Patent Images
1. An elastic wave device comprising:
- a piezoelectric film made of LiTaO3; and
an IDT electrode located on one surface of the piezoelectric film;
whereinthe IDT electrode includes a plurality of first electrode fingers and a plurality of second electrode fingers that are alternately arranged;
a thickness of the piezoelectric film is about 10λ
or less when λ
is a wavelength determined by a pitch of the electrode fingers of the IDT electrode; and
a direction of a line connecting distal ends of the plurality of first electrode fingers and a direction of a line connecting distal ends of the second electrode fingers are at an oblique angle ν
with respect to a propagation direction ψ
of an elastic wave excited by the IDT electrode, the propagation direction ψ
being determined by Euler angles (φ
, θ
, ψ
) of the LiTaO3, and the oblique angle ν
is in a range of about 0.4°
or more and about 15°
or less.
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Abstract
An elastic wave device includes IDT electrodes stacked on a piezoelectric thin film. The IDT electrode includes a plurality of first electrode fingers and a plurality of second electrode fingers. A line connecting the distal ends of the first electrode fingers or the distal ends of the second electrode fingers extends obliquely with respect to a propagation direction of an elastic wave at an oblique angle ν. The oblique angle ν is about 0.4° or more and about 10° or less.
27 Citations
24 Claims
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1. An elastic wave device comprising:
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a piezoelectric film made of LiTaO3; and an IDT electrode located on one surface of the piezoelectric film;
whereinthe IDT electrode includes a plurality of first electrode fingers and a plurality of second electrode fingers that are alternately arranged; a thickness of the piezoelectric film is about 10λ
or less when λ
is a wavelength determined by a pitch of the electrode fingers of the IDT electrode; anda direction of a line connecting distal ends of the plurality of first electrode fingers and a direction of a line connecting distal ends of the second electrode fingers are at an oblique angle ν
with respect to a propagation direction ψ
of an elastic wave excited by the IDT electrode, the propagation direction ψ
being determined by Euler angles (φ
, θ
, ψ
) of the LiTaO3, and the oblique angle ν
is in a range of about 0.4°
or more and about 15°
or less. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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2. An elastic wave device comprising:
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a piezoelectric film made of LiTaO3; a support substrate; a high acoustic velocity film that is located on the support substrate and in which an acoustic velocity of a bulk wave that propagates through the high acoustic velocity film is higher than an acoustic velocity of an elastic wave that propagates through the piezoelectric film; a low acoustic velocity film that is stacked on the high acoustic velocity film and in which an acoustic velocity of a bulk wave that propagates through the low acoustic velocity film is lower than an acoustic velocity of a bulk wave that propagates through the piezoelectric film; and an IDT electrode located on one surface of the piezoelectric film;
whereinthe piezoelectric film is stacked on the low acoustic velocity film; the IDT electrode includes a plurality of first electrode fingers and a plurality of second electrode fingers that are alternately arranged; a thickness of the piezoelectric film is about 10λ
or less when λ
is a wavelength determined by a pitch of the electrode fingers of the IDT electrode; anda direction of a line connecting distal ends of the plurality of first electrode fingers and a direction of a line connecting distal ends of the second electrode fingers are at an oblique angle ν
with respect to a propagation direction ψ
of an elastic wave excited by the IDT electrode, the propagation direction ψ
being determined by Euler angles (φ
, θ
, ψ
) of the LiTaO3, and the oblique angle ν
is in a range of about 0.4°
or more and about 15°
or less.
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3. An elastic wave device comprising:
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a piezoelectric film made of LiTaO3; a high acoustic velocity support substrate in which an acoustic velocity of a bulk wave that propagates through the high acoustic velocity support substrate is higher than an acoustic velocity of an elastic wave that propagates through the piezoelectric film; a low acoustic velocity film that is stacked on the high acoustic velocity support substrate and in which an acoustic velocity of a bulk wave that propagates through the low acoustic velocity film is lower than an acoustic velocity of a bulk wave that propagates through the piezoelectric film; and an IDT electrode located on one surface of the piezoelectric film;
whereinthe piezoelectric film is stacked on the low acoustic velocity film; the IDT electrode includes a plurality of first electrode fingers and a plurality of second electrode fingers that are alternately arranged; a thickness of the piezoelectric film is about 10λ
or less when λ
is a wavelength determined by a pitch of the electrode fingers of the IDT electrode; anda direction of a line connecting distal ends of the plurality of first electrode fingers and a direction of a line connecting distal ends of the second electrode fingers are at an oblique angle ν
with respect to a propagation direction ψ
of an elastic wave excited by the IDT electrode, the propagation direction ψ
being determined by Euler angles (φ
, θ
, ψ
) of the LiTaO3, and the oblique angle ν
is in a range of about 0.4°
or more and about 15°
or less.
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Specification