Abstract: A cavity overlapping an IDT electrode in a see-through plan view is formed between a piezoelectric layer and a support. An intersection region where first electrode fingers and second electrode fingers overlap each other includes a central region and two end regions located on both sides of the central region in one-to-one correspondence. The cavity overlaps the central region. An edge of the cavity on a side closer to the first busbar is located within a range from an edge of the central region on a side closer to the first busbar to an edge of the first busbar on a side opposite to the central region. The first electrode fingers extending from the first busbar each include a first portion located in the central region and a second portion located on a side closer to the first busbar or a side closer to the second busbar relative to the central region. A value of mass per unit length of the first electrode fingers above lower surfaces thereof is greater in the second portions than in the first portions.

Abstract: An elastic wave resonator includes a piezoelectric body, an IDT electrode positioned on the piezoelectric body, and a pair of reflectors. The IDT electrode includes a plurality of first electrode fingers arranged at a first pitch in a propagation direction of an elastic wave, and at least one second electrode finger formed at each end in the propagation direction of the plurality of first electrode fingers. The reflector is positioned at each end in the propagation direction of the IDT electrode and includes a plurality of strip electrodes arranged, in the propagation direction, at a second pitch wider than the first pitch or having a duty ratio higher than a duty ratio of any of the plurality of first electrode fingers and the at least one second electrode finger.

Abstract: The strength of a spurious signal is reduced while maintaining the uniformity of a resonant frequency in an identical elastic wave resonator. An elastic wave resonator (4) includes a piezoelectric body (6), and a plurality of electrode fingers (14, 22) located on the piezoelectric body and arranged in a propagation direction (TD) of an elastic wave. A region in which the plurality of electrode fingers are located includes a first region (24A) and a second region (24B) in a plan view. The plurality of electrode fingers include a first electrode finger group (14A) located in the first region and a second electrode finger group (14B) located in the second region, and a pitch (PA) of the first electrode finger group is different from a pitch (PB) of the second electrode finger group.

Abstract: An acoustic wave element includes an IDT electrode including a plurality of electrode fingers and exciting a surface acoustic wave, a first substrate including an upper surface on which the IDT electrode is located, the first substrate being configured by a piezoelectric crystal, and a second substrate bonded to a side where a lower surface of the first substrate is located. Either of a first region which continues from the lower surface of the first substrate toward a side where the upper surface is located or a second region which continues from the lower surface of the first substrate toward a side where the second substrate is located is a low resistance region having a resistance value of 5×103? to 5×107?.

Abstract: An acoustic wave device includes a substrate, a multilayer film on the substrate, an LT layer configured by a single crystal of LiTaO3 on the multilayer film, and an IDT electrode on the LT layer. The thickness of the LT layer is 0.3? or less where ? is two times a pitch p of electrode fingers in the IDT electrode. Euler angles of the LT layer are (0°±20°, ?5° to 65°, 0°±10°), (?120°±20°, ?5° to 65°, 0°±10°), or (120°±20°, ?5° to 65°, 0°±10°). The multilayer film configured by alternately stacking at least one first layer and at least one second layer. The first layer is comprised of SiO2. The second layer is comprised of any one of Ta2O5, HfO2, ZrO2, TiO2, and MgO.

Abstract: Provided is an acoustic wave device that uses a plate wave. The acoustic wave device includes a piezoelectric film and a first resonator and a second resonator each including an IDT electrode located on an upper surface of the piezoelectric film. The thickness of the piezoelectric film is smaller than twice the period of the electrode fingers of the IDT electrodes. The duty of the electrode fingers of the first resonator and the duty of the electrode fingers of the second resonator are different from each other.

Abstract: An elastic wave device includes a substrate, a multilayer film located on the substrate, an LT layer located on the multilayer film and made of a single crystal of LiTaO3, and an IDT electrode located on the LT layer. The LT layer has a thickness of 0.3? or less, where ? is twice a pitch of electrode fingers of the IDT electrode. The LT layer has Euler angles of (0°±10°, ?25° or more and 15° or less, 0° or more and 360° or less).

Abstract: An elastic wave device includes a substrate, a multilayer film located on the substrate, a piezoelectric layer located on the multilayer film, and an IDT electrode located on the piezoelectric layer. The IDT electrode includes electrode fingers each having a large width from a portion connected to a busbar to a position overlapping tip ends of the other electrode fingers when viewed in an arrangement direction of the electrode fingers.

Abstract: An acoustic wave device includes a substrate, a multilayer film on the substrate, an LT layer configured by a single crystal of LiTaO3 on the multilayer film, and an IDT electrode on the LT layer. The thickness of the LT layer is 0.3? or less where ? is two times a pitch p of electrode fingers in the IDT electrode. Euler angles of the LT layer are (0°±20°, ?5° to 65°, 0°±10°), (?120°±20°, ?5° to 65°, 0°±10°), or (120°±20°, ?5° to 65°, 0°±10°). The multilayer film is configured by alternately stacking at least one first layer and at least one second layer. The first layer is comprised of SiO2. The second layer is comprised of any one of Ta2O5, HfO2, ZrO2, TiO2, and MgO.

Abstract: A composite substrate includes a first substrate which is comprised of a lithium tantalate crystal and has Euler angles (0, ?, ?), and a second substrate which is comprised of a single crystal of silicon bonded to the first substrate and has Euler angles (?45, ?54.7, ?). In the composite substrate, ? is ?40° to ?60° or 120° to 140° and ? is 0° or 180°, and either of following conditions is satisfied. (1) ? is in a range of ?=?±20° and its equivalent orientation and (2) ? is in a range of ?+160°????+200°.

Abstract: An acoustic wave element includes an IDT electrode including a plurality of electrode fingers and exciting a surface acoustic wave, a first substrate including an upper surface on which the IDT electrode is located, the first substrate being configured by a piezoelectric crystal, and a second substrate bonded to a side where a lower surface of the first substrate is located. Either of a first region which continues from the lower surface of the first substrate toward a side where the upper surface is located or a second region which continues from the lower surface of the first substrate toward a side where the second substrate is located is a low resistance region having a resistance value of 5×103? to 5×107?.