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Sumitomo Electric Industries (SEI) wires the world through its more than 300 global companies and plants that supply infrastructure materials. Its electric wire and cable unit (40% of sales) makes products used in optical fibers, aircraft components, internal wiring in construction, communications terminals, and power transmission cable. SEI also makes cutting tools, automotive brake pads, network switches, fluororesin-coated aluminum for cookware, and prefabricated saddle systems for steel wire bridges. It also produces rubber products, sporting goods, and refined tungsten. SEI has a unit for new businesses that created the first optical-fiber grating laser diode (data transmission) for the telecom industry. Subsidiaries/Divisions JUDD WIRE Inc. Sumitomo Electric Carbide, Inc. Sumitomo Electric Lightwave Corp. Sumitomo Electric USA, Inc. / Kentucky Division Sumitomo Electric USA, Inc. / Los Angeles Office From the company's website: Sumitomo Electric has developed a new original white LED designed for use as backlights for liquid crystal displays in the rapidly growing field of cellular telephones and will begin mass-production this fall. We succeeded in developing white LEDs utilizing ZnSe (zinc selenide) in 1999 and have since worked to commercialize this device (Refer to attachment "Principle of White Light Emission."). In recent years, the number of cellular telephone subscribers has been on the rise resulting in the remarkable growth of the cellular telephone market. Color displays are now being incorporated in some of these products, a trend which is expected to expand rapidly. Currently, three or four LED lamps of the same color are used for the backlights of the liquid crystal of cellular telephone displays in order to avoid inhomogeneities in illumination. However, for color liquid crystal displays, a white backlight is needed. In this case, unless white LEDs are used, LED lamps of the three primary colors (red, green, blue) will be needed resulting in the total number of LED lamps required. We have steadily built up our integrated production system capable of manufacturing everything from the raw ZnSe material to the single-crystal substrate, the epitaxial thin film, and the final device. At this time, with the commercialization of our white LEDs, we have decided to install new equipment for manufacturing ZnSe substrates to LED chips as well as inspection equipment at the Osaka Works (Osaka city) . We are planning a monthly production of five million pieces beginning this fall while continuing to invest in new facilities and equipment as we carefully monitor the market trends toward color liquid crystal displays in cellular telephones. The features of Sumitomo Electric's white LEDs are as follow: 1. Small Deviation in Chromaticity A major problem with using multiple white LED lamps for a backlight of a color liquid crystal display in cellular telephones is the deviation in the chromaticity among the LEDs. Because our LEDs are produced by adding a small amount of dopant impurity in the ZnSe substrate, white light is emitted with very little deviation in chromaticity. 2. Low Power Consumption The use of a low-resistance ZnSe substrate results in an extremely small forward voltage. The lamp can be operated at voltages of less than 2.7 V and can be powered by two dry cell batteries. 3. Small Chip Size The use of a conductive substrate allows for the formation of electrodes on the top and bottom of the chip, thus making it possible to reduce its surface area (Development of a white LED chip in a size for conventional cellular telephones has already been completed.). 4. Utilization of Existing Resources Because the LED chip itself emits white light, the LED lamp manufacturers can produce white LED lamps using their own design and can continue to use their existing LED lamp manufacturing processes, which is not possible with other white LEDs. White LED lamps are not only applicable as backlights for color liquid crystal displays in cellular telephones, but can also be adopted as backlights for monochromatic displays in cellular telephones. White LED lamps are also being considered for use as backlights for liquid crystals in home electric appliances and mobile devices other than cellular telephones. As their performance improves, we expect white LEDs to find application in a number of areas including measuring instruments as well as indoor and outdoor information display devices. Principle of White Light Emission The ZnSe white LED, which we have been developing since 1998, produces white light by mixing blue light emitted from a ZnSe LED with green to red light emitted from the ZnSe substrate. The chromaticity of the white light is determined by the wavelength of the blue emitted light and the intensity of the green to red emitted light. Since the fluctuation of the wavelength of the blue light is small due to the light emission principle of the ZnSe LED, the deviation in the chromaticity of our white LED is only limited. The green to red light emitted from the substrate is the result of a phenomenon peculiar to ZnSe, in which the small amount of dopant contained in the ZnSe substrate causes the absorbtion of short-wavelength light (blue light in the case of the ZnSe white LED element) and converts it to longer-wavelength green to red light emitted from the substrate, i.e., the so-called photoluminescence (PL) phenomenon. Explanation of Terms Light-emitting diode(LED) A semiconductor light-emitting device that emits light (electroluminescence) by flowing a current through it. Unlike the laser diode, the phase and wavelengths are not coherent. LEDs are used in areas such as display devices, low-speed optical communication devices and sensors. Photoluminescence (PL) light emission A phenomenon where a substance is excited by external light resulting in the emission of longer-wavelength light.The phenomenon in which a substance is excited by flowing a current through it to emit light, as in an LED, is referred to as electroluminescence. Epitaxy A technology for growing a thin single-crystal film on a single-crystal substrate to form a semiconductor active layer. There are two methods in this technology: homoepitaxy (normally referred to as epitaxy) which forms a thin film from the same material as the substrate and heteroepitaxy which forms a thin film from a material different from that of the substrate. In heteroepitaxy, defects due to inconsistencies at the interface with the substrate generally occur on the thin film, thus making it extremely difficult to obtain a thin film with sufficiently small amount of defects for use as the semiconductor active layer. Molecular-beam epitaxy (MBE) An ultra high-vacuum vapor deposition process. This method allows precise control of the composition and thickness of the deposited layer and is employed in industry as a method for growing a thin single-crystal film on a single-crystal substrate. sei.co.jp Presently Trading at $134.77 52wkHI was $148.31 Chart is tscn.com Raging Bull, Bloomberg, and Hoovers show symbol is SMTOY. Jack | ||||||||||||
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