Abstract: An optical device includes: a base including a mounting surface; and an optical component including an optical element part, a support part including a first adhered surface bonded to the mounting surface via a photocurable first adhesive, the support part being configured to support the optical element part, and an optical opening part provided adjacent to the first adhered surface, the optical opening part allowing light for curing the first adhesive to pass through.

Abstract: An elastic wave device includes a high-acoustic-velocity film, a low-acoustic-velocity film, and a piezoelectric film stacked on a substrate in this order, and a bonding layer is disposed at any position from inside of the high-acoustic-velocity film to an interface between the low-acoustic-velocity film and the piezoelectric film. Alternatively, an elastic wave device includes a low-acoustic-velocity film and a piezoelectric film stacked on a high-acoustic-velocity substrate, and a bonding layer is located in the low-acoustic-velocity film or at an interface between the piezoelectric film and the low-acoustic-velocity film.

Abstract: An IDT electrode of an elastic wave device includes a first electrode film made of Al or mainly containing Al, a second electrode film with a density larger than that of the first electrode film, an anti-diffusion film which is located between the first electrode film and the second electrode film and which significantly reduces or prevents interdiffusion between the first electrode film and the second electrode film, and a first Ti film located between the first electrode film and the anti-diffusion film, to diffuse a diffusion material into the first electrode film.

Abstract: An acoustic wave device includes a high acoustic velocity support substrate defining and functioning as a high acoustic velocity member, a low acoustic velocity film, a piezoelectric film, and an IDT electrode that are laminated in this order. When a wavelength of an acoustic wave determined by an electrode finger cycle of the IDT electrode is represented by ?, a film thickness of the piezoelectric film is about 1.5? or more and about 3.5? or less. The acoustic velocity of a bulk wave propagating in the high acoustic velocity support substrate is higher than the acoustic velocity of an acoustic wave propagating in the piezoelectric film. The acoustic velocity of a bulk wave propagating in the low acoustic velocity film is lower than the acoustic velocity of an acoustic wave propagating in the piezoelectric film.

Abstract: An elastic wave device includes a high-acoustic-velocity film, a low-acoustic-velocity film, and a piezoelectric film stacked on a substrate in this order, and a bonding layer is disposed at any position from inside of the high-acoustic-velocity film to an interface between the low-acoustic-velocity film and the piezoelectric film. Alternatively, an elastic wave device includes a low-acoustic-velocity film and a piezoelectric film stacked on a high-acoustic-velocity substrate, and a bonding layer is located in the low-acoustic-velocity film or at an interface between the piezoelectric film and the low-acoustic-velocity film.

Abstract: An IDT electrode of an elastic wave device includes a first electrode film made of Al or mainly containing Al, a second electrode film with a density larger than that of the first electrode film, an anti-diffusion film which is located between the first electrode film and the second electrode film and which significantly reduces or prevents interdiffusion between the first electrode film and the second electrode film, and a first Ti film located between the first electrode film and the anti-diffusion film, to diffuse a diffusion material into the first electrode film.

Abstract: When an over-current is detected as flowing in semiconductor devices of a power converter by a Hall CT (current transformer), an abnormality detection unit outputs an abnormality signal. If the abnormality signal is output from the abnormality detection unit, a gate breaking unit of a gate driving unit outputs a gate breaking signal to stop the power converter. At the same time, a gate ON unit maintains the gate signal of the semiconductor device that has become abnormal in the ON state and, after the current in the semiconductor device has become smaller than a specified value, the gate signal of the semiconductor device is rendered OFF by a gate constriction device. By this operation, the current flowing in the semiconductor device may be reduced prior to any gate breaking operation occurring.