Abstract: An earth fault detection apparatus includes a switch group configured to switch between a first measurement path including a battery and a capacitor, a second measurement path including the battery, a negative-side insulation resistance, and the capacitor, a third measurement path including the battery, a positive-side insulation resistance, and the capacitor; and a control unit configured to calculate a reference value, based on each charging voltage of the capacitor in each measurement path, and configured to calculate an insulation resistance with reference to a predetermined conversion map, in which the conversion map includes a conversion map corresponding to a capacitance of the capacitor, and the control unit estimates the capacitance of the capacitor, and refers to the conversion map corresponding to the capacitance of the capacitor that has been estimated.

Abstract: A technique is provided herein whereby the size of piezoelectric filters can be reduced. A piezoelectric filter according to one aspect of the present disclosure has: a first substrate having a first main surface; a second substrate having a second main surface facing the first main surface; and a ladder circuit of Nth order, including N piezoelectric resonators, N being an integer of 3 or greater. In this piezoelectric filter, the first-order to Mth-order piezoelectric resonators included in the ladder circuit are formed on the first main surface, M being an integer from 1 to N?1, inclusive, and the (M+1)th-order to Nth-order piezoelectric resonators included in the ladder circuit are formed on the second main surface.

Abstract: The present invention provides a technique for making a film bulk acoustic resonator with ease, at low cost. A film bulk acoustic resonator, according to one aspect of the present disclosure has: a substrate having a first main surface; an oxide film provided over the first main surface; and a laminated film provided over the oxide film and including a first electrode, a piezoelectric layer, and a second electrode laminated in this order, and, in this film bulk acoustic resonator, a void where the oxide film is removed is provided between the substrate and the first electrode, and the piezoelectric layer has a through-hole that communicates with the void.

Abstract: An optical scanning device includes a mirror that includes a mirror reflection surface, a driving part that drives the mirror, and a fixed frame that supports the mirror via the driving part. The fixed frame includes one or more inspection patterns that are formed while at least one of the mirror and the driving part is formed.

Abstract: An optical scanning device includes: a pair of twist beams arranged on both sides of a mirror along a predetermined axis and configured to swing the mirror around the axis; a pair of connection beams connected to the respective twist beams; a piezoelectric sensor formed on the connection beams and configured to detect a displacement of the connection beams caused by a swing of the mirror around the axis; wherein the piezoelectric sensor includes a lower electrode; a piezoelectric thin film stacked on the lower electrode; and an upper electrode stacked on or above the piezoelectric thin film, wherein a bottom surface and a side surface of the piezoelectric thin film form a tilt angle ?, and wherein the tilt angle is greater than 0° and less than or equal to 50°.

Abstract: A light scanning apparatus for causing a mirror to oscillate to scan with light reflected by the mirror includes an interconnect formed of gold; a protective film for covering the interconnect; and an adhesive film formed between the interconnect and the protective film.

Abstract: An optical scanning device includes a mirror that includes a mirror reflection surface, a driving part that drives the mirror, and a fixed frame that supports the mirror via the driving part. The fixed frame includes one or more inspection patterns that are formed while at least one of the mirror and the driving part is formed.

Abstract: An optical scanning device includes: a pair of twist beams arranged on both sides of a mirror along a predetermined axis and configured to swing the mirror around the axis; a pair of connection beams connected to the respective twist beams; a piezoelectric sensor formed on the connection beams and configured to detect a displacement of the connection beams caused by a swing of the mirror around the axis; wherein the piezoelectric sensor includes a lower electrode; a piezoelectric thin film stacked on the lower electrode; and an upper electrode stacked on or above the piezoelectric thin film, wherein a bottom surface and a side surface of the piezoelectric thin film form a tilt angle ?, and wherein the tilt angle is greater than 0° and less than or equal to 50°.