Abstract: The elastic wave device of the present invention has an piezoelectric substrate; a first dielectric layer disposed on the piezoelectric substrate; a second dielectric layer disposed on the first dielectric layer; and an acoustical layer on the second dielectric layer. Determining each film thickness of the first and the second dielectric layers provides advantageous effects. That is, energy of an SH wave as a main wave is confined in the boundary between the piezoelectric substrate and the first dielectric layer, and at the same time, an SV wave is suppressed as an unwanted wave. The device allows the SV wave—whose displacement distribution is similar to that of Stoneley wave—to have displacement distribution on the upper surface of the second dielectric layer and to be suppressed by the acoustical layer disposed on the second dielectric layer.

Abstract: An acoustic wave device includes a piezoelectric substrate having a surface adapted to allow leaky surface wave to propagate thereon, an interdigital electrode provided on a portion of the surface of the piezoelectric substrate, and a dielectric layer provided on the surface of the piezoelectric substrate to cover the interdigital electrode. The piezoelectric substrate is made of lithium niobate. The dielectric layer is made of tantalum pentoxide. The piezoelectric substrate is made of a rotated Y-cut substrate having a cut angle which is not smaller than 2.5 degrees and is not larger than 22.5 degrees. A ratio H/? of a film thickness H of the dielectric layer to a wavelength ? of a center frequency of the leaky surface wave ranges from 0.034 to 0.126. This acoustic wave device works in a wide band width.

Abstract: An electronic part, object of which is to improve temperature characteristics and electrical properties, includes a substrate (1), a comb-type electrode (2) that is disposed on the upper surface of the substrate (1), and a protective film (4) that covers the comb-type electrode (2) and has an uneven shape at its top surface. If the pitch width of one pitch in the uneven shape of the protective film (4) is L, the width of one pitch of a convex portion (4a) of the unevenness in the uneven shape of the protective film (4) is L1, the width of one pitch of a concave portion (4b) thereof is L2, the pitch width of one pitch of the comb-type electrode (2) is p, the width of one of electrode fingers which form the comb-type electrode (2) is p1 and the width between the electrode fingers is p2, then each parameter is set so that the following expressions are satisfied, L1?p1and L2?p2(herein, the correlations of L?p, p1+p2=p and L1+L2=L are satisfied).

Abstract: An electronic part, an object of which is to improve temperature characteristics and electrical properties, includes a substrate (1), a comb-type electrode (2) that is disposed on the upper surface of the substrate (1), and a protective film (4) that covers the comb-type electrode (2) and has an uneven shape at its top surface. If the pitch width of one pitch in the uneven shape of the protective film (4) is L, the width of one pitch of a convex portion (4a) of the unevenness in the uneven shape of the protective film (4) is L1, the width of one pitch of a concave portion (4b) thereof is L2, the pitch width of one pitch of the comb-type electrode (2) is p, the width of one of electrode fingers which form the comb-type electrode (2) is p1 and the width between the electrode fingers is p2, then each parameter is set so that the following expressions are satisfied, L1?p1 and L2?p2 (herein, the correlations of L?p, p1+p2=p and L1+L2=L are satisfied).

Abstract: A plurality of surface acoustic wave resonators including a comb electrode and a grating reflector are coupled on a piezoelectric substrate. Dielectric film is formed on the surface of at least one surface acoustic wave resonator. No dielectric film is formed on the surface of at least one other surface acoustic wave resonator. Thus, a SAW filter where the insertion loss into a pass band is small, the steepness is sufficient, and the band is wide can be obtained.

Abstract: A surface acoustic wave filter includes a piezoelectric substrate including lithium niobate, a series resonator including a first interdigital transducer electrode provided on the piezoelectric substrate, and a parallel resonator including a second interdigital transducer electrode provided on the piezoelectric substrate and being electrically connected to the series resonator. An apodized weighting factor of the first interdigital transducer electrode is smaller than an apodized weighting factor of the second interdigital transducer electrode. This surface acoustic wave filter has a small loss.

Abstract: A plurality of surface acoustic wave resonators (15through 20) including a comb electrode and a grating reflector are coupled on piezoelectric substrate (12). Dielectric film (14) is formed on the surface of at least one surface acoustic wave resonator, of surface acoustic wave resonators (15 through 20). No dielectric film (14) is formed on the surface of at least another surface acoustic wave resonator. Thus, an SAW filter where the insertion loss into a band is small, the steepness is sufficient, and the band is wide can be obtained.

Abstract: In a surface acoustic wave (SAW) device, such as a SAW resonator or a SAW filter, loss is minimized and steep characteristics are improved. IDT electrodes and a reflector are provided to a piezoelectric substrate cut out at a cut-angle which allows the substrate to excite a leaky surface acoustic wave (LSAW). The IDT electrodes have a given film thickness and a given pitch “p” of finger-electrodes. A phase velocity of the SAW is reduced to slower than a phase velocity “vb”of a slow shear wave propagating on the piezoelectric substrate, and a resonance frequency “f” satisfies a relation of 2×p?vb/f. This structure allows the use of a Rayleigh surface acoustic wave (RSAW) which does not produce propagation loss, and improving insertion-loss and steep characteristics from those of a conventional SAW device using the LSAW.

Abstract: The present invention relates to an electronic part, and its object is to improve temperature characteristics and electrical properties. In order to attain the object, the electronic part according to the present invention includes a substrate (1), a comb-type electrode (2) that is disposed on the upper surface of the substrate (1), and a protective film (4) that covers the comb-type electrode (2) and has an uneven shape at its top surface.

Abstract: In a surface acoustic wave (SAW) filter including a substrate and an electrode formed on the substrate, the electrode includes a base layer, a first metal layer made of a metal consisting of Al or consisting mainly of Al, and having a given orientation relative to the substrate, a second layer for preventing the first metal layer from migration of Al atoms occurring in vertical to the substrate, and a third layer for adjusting a thickness of the layer. In this SAW filter having an arbitrary layer thickness, the layer hardly causes grain boundary diffusion, and grains of the layer can be made fine for effective resistance to stress. Thus, in this SAW filter, the migration of the Al atoms of the electrode that is associated with the SAW propagation-induced stress imposed on the electrode is inhibited. Accordingly, the filter exhibits excellent resistance against electric power.

Abstract: In a surface acoustic wave (SAW) device such as a SAW resonator or a SAW filter, loss is minimized and steep characteristics are improved. IDT electrodes and a reflector are provided to a piezoelectric substrate cut out at a cut-angle which allows the substrate to excite leaky surface acoustic wave (LSAW). The IDT electrodes have a given film thickness and a given pitch “p” of finger-electrodes. An phase velocity of the SAW is reduced to slower than an phase velocity “vb” of a slow shear wave propagating on the substrate, and resonance frequency “f” satisfies a relation of 2×p≦vb/f. This structure allows using Rayleigh surface acoustic wave (RSAW) which does not produce propagation loss, and improving insertion-loss and steep characteristics from those of a conventional SAW device using LSAW.

Abstract: In a surface acoustic wave (SAW) filter including a substrate and an electrode formed on the substrate, the electrode includes a base layer, a first metal layer made of a metal consisting of Al or consisting mainly of Al, and having a given orientation relative to the substrate, a second layer for preventing the first metal layer from migration of Al atoms occurring in vertical to the substrate, and a third layer for adjusting a thickness of the layer. In this SAW filter having an arbitrary layer thickness, the layer hardly causes grain boundary diffusion, and grains of the layer can be made fine for effective resistance to stress. Thus, in this SAW filter, the migration of the Al atoms of the electrode that is associated with the SAW propagation-induced stress imposed on the electrode is inhibited. Accordingly, the filter exhibits excellent resistance against electric power.