Abstract:
An apparatus for fabricating a 3D scaffold includes: a plotter generating a microfiber structure; an electrospinning unit installed to be adjacent to the plotter along a first direction and spinning nanofiber in an internal space or on a surface of the microfiber structure to form a nanofiber web; a collection table reciprocating a lower portion of the plotter and that of the electrospinning unit along the first direction to allow the microfiber structure to be stacked thereon by the plotter and allow the nanofiber web to be formed thereon by the electrospinning unit; and a first guide rail allowing the collection table to be mounted thereon and guiding the collection table mounted thereon to reciprocate along the first direction.
Abstract:
AC LED according to the present invention comprises a substrate, and at least one serial array having a plurality of light emitting cells connected in series on the substrate. Each of the light emitting cells comprises a lower semiconductor layer consisting of a first conductive compound semiconductor layer formed on top of the substrate, an upper semiconductor layer consisting of a second conductive compound semiconductor layer formed on top of the lower semiconductor layer, an active layer interposed between the lower and upper semiconductor layers, a lower electrode formed on the lower semiconductor layer exposed at a first corner of the substrate, an upper electrode layer formed on the upper semiconductor layer, and an upper electrode pad formed on the upper electrode layer exposed at a second corner of the substrate. The upper electrode pad and the lower electrode are respectively disposed at the corners diagonally opposite to each other, and the respective light emitting cells are arranged so that the upper electrode pad and the lower electrode of one of the light emitting cells are symmetric with respect to those of adjacent another of the light emitting cells.
Abstract:
Disclosed is an AC light emitting device having photonic crystal structures and a method of fabricating the same. The light emitting device includes a plurality of light emitting cells and metallic wirings electrically connecting the light emitting cells with one another. Further, each of the light emitting cells includes a first conductive type semiconductor layer, a second conductive type semiconductor layer disposed on one region of the first conductive type semiconductor layer, and an active layer interposed between the first and second conductive type semiconductor layers. In addition, a photonic crystal structure is formed in the second conductive type semiconductor layer. The photonic crystal structure prevents light emitted from the active layer from laterally propagating by means of a periodic array, such that light extraction efficiency of the light emitting device can be improved. Furthermore, the metallic wirings electrically connect a plurality of light emitting cells with one another such that an AC light emitting device can be provided.
Abstract:
Disclosed is an optical system for a head mount display, including at least a display unit that is provided on an inner surface of a leg area of an eyeglass frame to provide virtual screen light, an optical path adjusting unit that is provided on a nose support area of the eyeglass frame to convert a direction of the virtual screen light delivered from the display unit by refracting or reflecting the virtual screen light, and an optical coupling unit that is provided in an interior of an eyeglass lens or at a location that is adjacent to the eyeglass lens to combine a virtual screen and a reality screen that is introduced from the outside and deliver the combined screen to the eyes of a wearer.
Abstract:
There is provided a light emitting diode operating under AC power comprising a substrate; a buffer layer formed on the substrate; and a plurality of light emitting cells formed on the buffer layer to have different sizes and to be electrically isolated from one another, the plurality of light emitting cells being connected in series through metal wires.According to the present invention, light emitting cells formed in an LED have different sizes, and thus have different turn-on voltages when light is emitted under AC power, so that times when the respective light emitting cells start emitting light are different to thereby effectively reduce a flicker phenomenon.
Abstract:
The present invention provides a method of fabricating a light emitting diode chip having an active layer between an N type semiconductor layer and a P type semiconductor layer. The method comprises the steps of preparing a substrate; laminating the semiconductor layers on the substrate, the semiconductor layers having the active layer between the N type semiconductor layer and the P type semiconductor layer; and forming grooves on the semiconductor layers laminated on the substrate until the substrate is exposed, whereby inclined sidewalls are formed by the grooves in the semiconductor layers divided into a plurality of chips. According to embodiments of the present invention, a sidewall of a semiconductor layer formed on a substrate of a light emitting diode chip is inclined with respect to the substrate, whereby its directional angle is widened as compared with a light emitting diode chip without such inclination. As the directional angle of the light emitting diode chip is wider, when a white light emitting device is fabricated using the light emitting diode chip and a phosphor, light uniformity can be adjusted even though the phosphor is not concentrated at the center of the device. Thus, the overall light emitting efficiency can be enhanced by reducing a light blocking phenomenon caused by the increased amount of the phosphor distributed at the center portion.