Abstract: A micro speaker includes a substrate having a cavity formed therein, a diaphragm formed on the substrate overlapping the cavity. The diaphragm includes a first vibration membrane formed in a first area corresponding to a center portion of the cavity and a second vibration membrane formed in a second area corresponding to an edge portion of the cavity and formed of material different from that used for the first vibration membrane. A piezoelectric actuator is formed including a first electrode layer formed on the first vibration membrane, a piezoelectric layer formed on the first electrode layer, and a second electrode layer formed on the piezoelectric layer, and first and second curved lead wires, respectively connected to the first and second electrode layers across the second area, which are symmetrical to the center of the piezoelectric actuator.

Abstract: Provided are a piezoelectric micro speaker and a method of manufacturing the same. The piezoelectric micro speaker includes: a substrate having a cavity therein; a diaphragm that is disposed on the substrate, the diaphragm including a vibrating membrane that overlaps the cavity; a piezoelectric actuator that is disposed on the vibrating membrane; and a weight that is disposed in the cavity and attached to a center portion of the vibrating membrane.

Abstract: A piezoelectric micro speaker and a method of manufacturing the same are provided. The piezoelectric micro speaker includes a substrate having a cavity formed therein and a diaphragm that is disposed on the substrate that overlaps the cavity. A plurality of first vibrating membranes having concentric annular ring shapes are disposed in a first region of the diaphragm corresponding to a center of the cavity. A second vibrating membrane including a different material from that of the first vibrating membranes is formed in the second region of the diaphragm corresponding to an edge of the cavity. A piezoelectric actuator for vibrating the first vibrating membranes is formed on and between the concentric annular rings of the first vibrating membranes.

Abstract: Provided are a piezoelectric micro speaker having a piston diaphragm and a method of manufacturing the piezoelectric micro speaker. The piezoelectric micro speaker includes: a substrate having a cavity formed therein; a vibrating membrane that is disposed on the substrate and covers at least a center part of the cavity; a piezoelectric actuator disposed on the vibrating membrane so as to vibrate the vibrating membrane; and a piston diaphragm that is disposed in the cavity and performs piston motion by vibration of the vibrating membrane. When the vibrating membrane vibrates by the piezoelectric actuator, the piston diaphragm, which is connected to the vibrating membrane through a piston bar, performs a piston motion in the cavity.

Abstract: A piezoelectric micro speaker and a method of manufacturing the same are provided. The piezoelectric micro speaker includes a device plate, a front plate bonded on a front surface of the device plate, and a rear plate bonded on a rear surface of the device plate. The device plate includes a diaphragm, a piezoelectric actuator that vibrates the diaphragm, and a front cavity disposed in front of the diaphragm. The front plate includes a radiation hole connected to the front cavity. The rear plate includes a rear cavity formed in a surface of the rear plate facing the piezoelectric actuator, and a bent hole connected to the rear cavity. A sound absorption layer is formed on an inner surface of the rear cavity and absorbs sound radiated backward from the diaphragm so as to suppress the sound from being reflected on the rear plate.

Abstract: Provided are a piezoelectric acoustic transducer and a method of fabricating the same. In the piezoelectric acoustic transducer, a piezoelectric portion is formed in a portion of a diaphragm, and a deformation layer is formed in another portion of the diaphragm. Deformation of the piezoelectric portion is transferred to the deformation layer, or deformation of the deformation layer is transferred to the piezoelectric layer so that the deformation layer vibrates with the piezoelectric layer.

Abstract: Provided is a method of fabricating a piezoelectric microspeaker. According to the method, drive units having a piezoelectric layer and an electrode are symmetrically formed so as to be disposed over and under a diaphragm, respectively. When a thin conductive layer is used as the diaphragm, the diaphragm can be used as a common electrode. On the other hand, when a thin non-conductive layer is used as the diaphragm, a common electrode is necessary in each of the drive units.

Abstract: Provided are a piezoelectric microspeaker and a method of fabricating the same. In the piezoelectric microspeaker, a diaphragm includes a first region and a second region. The first region may be formed of a material capable of maximizing an exciting force, and the second region may be formed of a material having less initial stress and a lower Young's modulus than the first region.

Abstract: A method for fabricating a micro speaker is provided, including forming a package wafer and a device wafer by batch processing, bonding the package wafer and the device wafer to each other, and forming a diaphragm by isotropic-etching a back surface of the device wafer using a xenon difluoride (XeF2). As a result, a micro-electronic-mechanic system (MEMS) technology-based piezoelectric micro speaker having a wide frequency response range is realized, by batch processing, thereby providing simplified structure and processing and reducing fabricating cost.

Abstract: A micro optical bench structure and a method of manufacturing a micro optical bench structure are provided. The micro optical bench structure includes: a lower substrate; an upper substrate which is bonded to the lower substrate, and has a through-hole for exposing the lower substrate; and a first optical device which is installed at the lower substrate, and units relating to the first optical device.

Abstract: An electromagnetic micro-actuator is provided that includes a stage rotatably formed on a surface of a substrate; first and second torsion springs respectively connected to opposite sides of the stage in a rotation axis direction; a fixed frame that supports the first and second torsion springs and surrounds the stage; a driving coil wound to a predetermined depth in an upper surface of the stage; a mirror unit formed on a side of the driving coil that is in the stage; and first and second permanent magnets respectively formed on opposite sides of the fixed frame so as to face each other.

Abstract: A method of manufacturing a coil for a micro-actuator. The method of manufacturing a coil for a micro-actuator includes preparing a substrate, forming a plurality of trenches for forming a coil on the substrate, covering portions on the substrate with a masking layer except for the plurality of trenches, electroplating the plurality of trenches with a conductive material, and forming a passivation layer on the substrate. Consistent with the method, variations in sections of a coil can be reduced by minimizing bending and warping of a wafer, and therefore a driving current applied to a coil and power consumption can be reduced.

Abstract: A shadow mask, a method of manufacturing the shadow mask, and a method of forming a thin film using the shadow mask are provided. The shadow mask includes an upper layer and a lower layer. The upper layer includes a first opening. The lower layer is formed on a lower surface of the upper layer around the first opening and includes an opening having the same size as the first opening. When the thin film is formed using the shadow mask, the lower layer of the shadow mask is close to the edge of a cavity of a substrate, and a position on which the thin film may be formed as defined by the lower layer of the shadow mask. Therefore, the thickness of the thin film can be uniform.

Abstract: A method of fabricating a one-way transparent optical system by which external light is effectively intercepted and internal light passes nearly without loss is provided. The method includes: forming a photoresist on an upper surface of a transparent substrate; heating and carbonizing the photoresist to form a black body layer; patterning the black body layer to form a plurality of light-absorbing materials on the transparent substrate; and forming protrusion structures having a shape of a convex lens shape for refracting incident light toward a corresponding light-absorbing material of the light-absorbing materials, on the transparent substrate on which the light-absorbing materials are formed.

Abstract: A micro-electro mechanical system (MEMS) device and a method of forming comb electrodes of the MEMS device are provided.

Abstract: A method of etching decoupled comb electrodes by self-alignment is provided The etching method is a self-alignment etching method for forming upper comb electrodes in a first silicon layer of a silicon on insulator (SOI) substrate and lower comb electrodes in a second silicon layer of the SOI substrate.

Abstract: A mirror structure and an optical scanner having the same which may achieve a high resolution since dynamic deformation is small while having a large driving angle. A plurality of vertical ribs are formed in a rear of the mirror of a scanner that reflects light, and are vertical to a torsional axis which is a center of vibration of the mirror. A horizontal rib is spaced apart from the torsional axis by a predetermined distance, and vertical to the vertical ribs. Optimum design parameters such as a size of the mirror, a moment of inertia, a driving angle, and dynamic deformation which are relevant to each other may be derived. Accordingly, the mirror may rotate at high speed and emit an image signal to a precise location.

Abstract: A micro-electro mechanical system (MEMS) device that uses an SOI wafer, and a method of manufacturing the same. The MEMS device includes an SOI wafer including a first silicon layer, a second silicon layer, and an insulating layer formed between the first and second silicon layers, and a protective substrate that is bonded to the first silicon layer, wherein grounding via holes are formed through the first silicon layer, the insulating layer and the protective substrate, and filled with a conductive material, and ventilation holes to be connected to the grounding via holes are formed in the second silicon layer.

Abstract: A method of forming comb electrodes using self alignment etching is provided. A method of forming a stationary comb electrode and a movable comb electrode in first and second silicon layers of a SOI (Silicon-on-Insulator) substrate, respectively, using etching. The method involves sequentially etching the first silicon layer, the insulating layer, and the second silicon layer using an alignment mark formed in the first silicon layer. According to the method, the stationary comb electrode and the movable comb electrode are self-aligned for etching by patterning the first silicon layer.

Abstract: A silicon-on-insulator (SOI) substrate including laminated layers of a substrate, an oxide layer, and a silicon layer in order. The oxide layer has an electrifying hole fluidly connected with the substrate and the electrifying hole is filled with a part of the silicon layer. A method for fabricating the floating structure is also disclosed which includes the steps of forming an oxide layer having a predetermined thickness on a substrate, forming one or more electrifying holes in an area of the oxide layer corresponding to an inner part of the floating structure, forming a silicon layer on the oxide layer including an electrification structure electrically connecting the silicon layer to the substrate, forming a pattern for the floating structure on the silicon layer, removing the oxide layer corresponding to an inner area of the pattern, forming a thermal oxide layer on a surface of the silicon layer, and removing the thermal oxide layer to form the floating structure.