Abstract:
Exemplary embodiments of the present invention provide light-emitting diodes having a distributed Bragg reflector. A light-emitting diode (LED) according to an exemplary embodiment includes a light-emitting structure arranged on a first surface of a substrate, the light-emitting structure including a first conductivity-type semiconductor layer, a second conductivity-type semiconductor layer, and an active layer interposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer. A first distributed Bragg reflector is arranged on a second surface of the substrate opposite to the first surface, the first distributed Bragg reflector to reflect light emitted from the light-emitting structure. The first distributed Bragg reflector has a reflectivity of at least 90% with respect to light of a first wavelength in a blue wavelength range, light of a second wavelength in a green wavelength range, and light of a third wavelength in a red wavelength range. The first distributed Bragg reflector has a laminate structure having an alternately stacked SiO2 layer and Nb2O5 layer.
Abstract:
Disclosed are a light emitting device and a method of fabricating the same. The light emitting device comprises a substrate. A plurality of light emitting cells are disposed on top of the substrate to be spaced apart from one another. Each of the light emitting cells comprises a first upper semiconductor layer, an active layer, and a second lower semiconductor layer. Reflective metal layers are positioned between the substrate and the light emitting cells. The reflective metal layers are prevented from being exposed to the outside.
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.
Abstract:
Disclosed herein is a light emitting diode. The light emitting diode includes a support substrate, semiconductor layers formed on the support substrate, and a metal pattern located between the support substrate and the lower semiconductor layer. The semiconductor layers include an upper semiconductor layer of a first conductive type, an active layer, and a lower semiconductor layer of a second conductive type. The semiconductor layers are grown on a sacrificial substrate and the support substrate is homogeneous with the sacrificial substrate.
Abstract:
The present invention discloses a light emitting diode (LED) including a plurality of light emitting cells arranged on a substrate. The LED includes half-wave light emitting units each including at least one light emitting cell, each half-wave light emitting unit including first and second terminals respectively arranged at both ends thereof; and full-wave light emitting units each including at least one light emitting cell, each full-wave light emitting units including third and fourth terminals respectively formed at both ends thereof. The third terminal of each full-wave light emitting unit is electrically connected to the second terminals of two half-wave light emitting units, and the fourth terminal of each full-wave light emitting unit is electrically connected to the first terminals of other two half-wave light emitting units. Also, a first half-wave light emitting unit is connected in series between the third terminal of a first full-wave light emitting unit and the fourth terminal of a second full-wave light emitting units, and a second half-wave light emitting units is connected in series between the fourth terminal of the first full-wave light emitting unit and the third terminal of the second full-wave light emitting unit.
Abstract:
Disclosed are an AC light emitting device with a long-persistent phosphor and an AC light emitting device module having the same. According to an exemplary embodiment of the present invention, the light emitting device includes a first light emitting diode chip and a second light emitting diode chip, each of which has a plurality of light emitting cells on a single substrate. Further, a first long-persistent phosphor is positioned on the first light emitting diode chip to perform wavelength conversion for a portion of light emitted from the first light emitting diode chip; and a second long-persistent phosphor is positioned on the second light emitting diode chip to perform wavelength conversion for a portion of light emitted from the second light emitting diode chip. The afterglow luminescence resulted from the second long-persistent phosphor is allowed to be different from that resulted from the first long-persistent phosphor, whereby a flicker effect of the AC light emitting device can be more alleviated.
Abstract:
The present invention relates to a light emitting device and a method of manufacturing the light emitting device. According to the present invention, the light emitting device comprises a substrate, an N-type semiconductor layer formed on the substrate, and a P-type semiconductor layer formed on the N-type semiconductor layer, wherein a side surface including the N-type or P-type semiconductor layer has a slope of 20 to 80° from a horizontal plane. Further, the present invention provides a light emitting device comprising a substrate formed with a plurality of light emitting cells each including an N-type semiconductor layer and a P-type semiconductor layer formed on the N-type semiconductor layer, and a submount substrate flip-chip bonded onto the substrate, wherein the N-type semiconductor layer of one light emitting cell and the P-type semiconductor layer of another adjacent light emitting cell are connected to each other, and a side surface including at least the P-type semiconductor layer of the light emitting cell has a slope of 20 to 80° from a horizontal plane. Further, the present invention provides a method of manufacturing the light emitting device. Accordingly, there is an advantage in that the characteristics of a light emitting device such as luminous efficiency, external quantum efficiency and extraction efficiency are enhanced and the reliability is secured such that light with high luminous intensity and brightness can be emitted.
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 herein are a patterned substrate for a light emitting diode and a light emitting diode employing the patterned substrate. The substrate has top and bottom surfaces. Protrusion patterns are arranged on the top surface of the substrate. Furthermore, recessed regions surround the protrusion patterns. The recessed regions have irregular bottoms. Thus, the protrusion patterns and the recessed regions can prevent light emitted from a light emitting diode from being lost due to the total reflection to thereby improve light extraction efficiency.
Abstract:
A light emitting diode (LED) chip for high voltage operation and an LED package including the same are disclosed. The LED chip includes a substrate, a first array formed on the substrate and including n light emitting cells connected in series, and a second array formed on the substrate and including m (m≦n) light emitting cells connected in series. During operation of the LED chip, the first array and the second array are operated by being connected in reverse parallel to each other. Further, when a driving voltage of the first array is delined as Vd1 and a driving voltage of the second array is defined as Vd2, a difference between Vd1 and Vd2×(n/m) is not more than 2V.