Abstract: A bulk acoustic resonator includes a substrate, a frequency control layer changing a resonant frequency or antiresonant frequency of the bulk acoustic resonator according to a thickness of the frequency control layer, a piezoelectric layer disposed between the frequency control layer and the substrate, a first electrode disposed between the piezoelectric layer and the substrate, a second electrode disposed between the piezoelectric layer and the frequency control layer, a metal layer connected to the first electrode or the second electrode, and a protective layer disposed between the second electrode and the frequency control layer, wherein the frequency control layer covers a larger area than that of the protective layer.

Abstract: A wearable device which is lighter, relatively safer at the time of breakage, and smaller than a wearable device having a lens substrate that is a glass substrate.

Abstract: A method for manufacturing a plastic substrate having excellent thickness uniformity, and a plastic substrate having excellent thickness uniformity manufactured thereby.

Abstract: A circuit board according to an embodiments includes an insulating portion comprising a plurality of insulating layers, wherein the insulating portion includes: a first insulating portion; a second insulating portion disposed on the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; and a third insulating portion disposed under the first insulating portion and having a coefficient of thermal expansion corresponding to the first insulating portion; wherein the first insulating portion includes a prepreg including glass fibers, and wherein the second and third insulating portions include a resin coated copper (RCC) with a coefficient of thermal expansion in the range of 10 to 65 (10?6 m/m·k).

Abstract: A bulk acoustic wave resonator is provided. The bulk acoustic wave resonator includes a board; a resonant portion including a first electrode, a piezoelectric layer, and a second electrode, and disposed on the board, and a temperature compensation layer disposed on the resonant portion, wherein the temperature compensation layer includes a temperature compensation portion formed of a dielectric and a loss compensation portion formed of a material different from a material of the temperature compensation portion, and wherein each of the temperature compensation portion and the loss compensation portion includes a plurality of linear patterns, and the linear patterns of the temperature compensation portion and the linear patterns of the loss compensation portion are alternately disposed.

Abstract: A printed circuit board according to an embodiment includes: an insulating layer; and a circuit pattern disposed on the insulating layer, wherein the circuit pattern includes an upper surface, a lower surface, a first side surface, and a second side surface, and surface roughness Ra of at least three surfaces of the upper surface, the lower surface, the first side surface, and the second side surface of the circuit pattern is 0.1 ?m to 0.31 ?m.

Abstract: A printed circuit board according to an embodiment includes an insulating layer; a first pad disposed on an upper surface of the insulating layer; a second pad disposed on a lower surface of the insulating layer; a first device mounted on the first pad; a second device mounted on the second pad; a first molding layer disposed on the insulating layer and molding the first device; and a second molding layer disposed on the lower surface of the insulating layer and molding the second device, wherein a lower surface of the second molding layer is positioned on the same plane as a lower surface of the second device.

Abstract: A bulk acoustic wave resonator includes: a substrate; a membrane layer forming a cavity together with the substrate; a lower electrode disposed on the membrane layer; a piezoelectric layer disposed on a flat surface of the lower electrode; and an upper electrode covering a portion of the piezoelectric layer and exposing a side of the piezoelectric layer to air, wherein the piezoelectric layer includes a step portion extended from the side of the piezoelectric layer and disposed on the flat surface of the lower electrode.

Abstract: A circuit board according to an embodiment includes a first insulating portion including at least one insulating layer; a second insulating portion disposed on the first insulating portion and including at least one insulating layer; and a third insulating portion disposed under the first insulating portion and including at least one insulating layer; wherein the insulating layer constituting the first insulating portion includes a prepreg containing glass fibers, and wherein each of the insulating layers constituting the second and third insulating portions is made of resin coated copper (RCC).

Abstract: A bulk acoustic resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; and an insertion layer disposed below a partial region of the piezoelectric layer. A thickness of the first electrode in an active region in which the first electrode, the piezoelectric layer, and the second electrode overlap one another is less than a thickness of a region outside the active region. An angle of inclination of an internal side surface of the insertion layer is different from an angle of inclination of an external side surface of the insertion layer.

Abstract: A circuit board according to an embodiment comprises: an insulating layer; a circuit pattern disposed above the top surface of or below the bottom surface of the insulating layer; and a buffer layer disposed between the insulating layer and the circuit pattern, the buffer layer comprising carbon atoms, nitrogen atoms, oxygen atoms, silicon atoms, sulfur atoms, and metal atoms, wherein: the ratio of the carbon atoms to the metal atoms ((carbon atom/copper atom)*100) is 5-7; the ratio of the nitrogen atoms to the metal atoms ((nitrogen atom/copper atom)*100) is 1.5-7; the ratio of the oxygen atoms to the metal atoms ((oxygen atom/copper atom)*100) is 1.1-1.9; and the ratio of the silicon atoms to the metal atoms ((silicon atom/copper atom)*100) is 0.5-0.9; and the ratio of the sulfur atoms to the metal atoms ((sulfur atom/copper atom)*100) is 0.5-1.5.

Abstract: A printed circuit board according to an embodiment includes: an insulating layer; and a circuit pattern disposed on the insulating layer, wherein the circuit pattern includes an upper surface, a lower surface, a first side surface, and a second side surface, and surface roughness Ra of at least three surfaces of the upper surface, the lower surface, the first side surface, and the second side surface of the circuit pattern is 0.1 ?m to 0.31 ?m.

Abstract: A bulk-acoustic wave resonator includes a resonator having a central portion in which a first electrode, a piezoelectric layer, and a second electrode are sequentially stacked on a substrate, and an extension portion disposed along a periphery of the central portion and in which an insertion layer is disposed below the piezoelectric layer, wherein the insertion layer includes a SiO2 thin film injected with fluorine (F).

Abstract: A bulk-acoustic wave resonator includes a resonator, including a first electrode, a piezoelectric layer, and a second electrode sequentially stacked on a substrate; and an insertion layer disposed below the piezoelectric layer, and configured to partially elevate the piezoelectric layer and the second electrode, wherein the insertion layer may be formed of a material containing silicon (Si), oxygen (O), and nitrogen (N).

Abstract: A bulk acoustic resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; a metal pad connected to the first electrode and the second electrode; and a protective layer disposed to cover at least the metal pad.

Abstract: A bulk acoustic wave resonator includes a substrate; a lower electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the lower electrode; an upper electrode disposed to cover at least a portion of the piezoelectric layer; and a passivation layer disposed to cover at least a portion of the upper electrode, wherein the passivation layer includes a non-trimming-processed portion disposed outside an active region of the bulk acoustic wave resonator in which portions of the lower electrode, the piezoelectric layer, and the upper electrode overlap, and having a thickness that is thicker than a thickness of a portion of the passivation layer disposed in the active region.

Abstract: A bulk acoustic resonator includes: a substrate; a first electrode disposed on the substrate; a piezoelectric layer disposed to cover at least a portion of the first electrode; a second electrode disposed to cover at least a portion of the piezoelectric layer; and an insertion layer disposed below a partial region of the piezoelectric layer. A thickness of the first electrode in an active region in which the first electrode, the piezoelectric layer, and the second electrode overlap one another is less than a thickness of a region outside the active region. An angle of inclination of an internal side surface of the insertion layer is different from an angle of inclination of an external side surface of the insertion layer.

Abstract: A bulk acoustic wave resonator includes a membrane layer, together with a substrate, forming a cavity, a lower electrode disposed on the membrane layer, a piezoelectric layer disposed on a flat surface of the lower electrode and an upper electrode covering a portion of the piezoelectric layer. An overall region at a side of the piezoelectric layer is exposed to the air. The side of the piezoelectric layer has a gradient of 65° to 90° with respect to a top surface of the lower electrode.

Abstract: A coil electronic component includes a body and external terminals. The body includes a winding coil part and a pillar-shaped core part inserted inside of the winding coil part and formed of a magnetic metal. The external terminals are connected to the winding coil part and disposed on an external surface of the body. The body contains the magnetic metal and a resin, and the pillar-shaped core part has magnetic permeability higher than that of a portion of the body disposed outside of the winding coil part.

Abstract: An ATSC 3.0 standard conformity assessment test system is configured to automatically perform an ATSC 3.0 standard conformity assessment test. The system includes: a broadcast network transmitter for modulating inputted transmission data according to a number of modulation combinations defined by the ATSC 3.0 standard to generate a broadcast network assessment stream, and transmitting the generated broadcast network assessment stream through a broadcast network (RF) in response to a control signal applied thereto; an IP test server for transmitting a communication network test stream for an Internet-based ATSC 3.0 service test using an IP communication network in response to a control signal applied thereto; and a device under test (DUT) for transmitting reception information with respect to the broadcast network assessment stream transmitted from the broadcast network transmitter and the communication network test stream transmitted from the IP test server to the IP test server through a feedback channel.