In this study, cup-shaped copper sheets were developed to improve heat dispassion for high-power light emitting diodes (LEDs) array module (3 × 3, 4 × 4, and 5 × 5) using an electroplating technique. The cup-shaped copper sheets were directly contacted with sapphire to enhance the heat dissipation of the chip itself. The lateral emitting light extraction and heat dissipation of high-power LEDs were enhanced and efficient. The surface temperature was not only decreasing but also uniform for each LED chip with the cup-shaped copper heat spreader adoption. The high thermal transmitting performance of cup-shaped copper heat spreader allows thermal resistance reducing 0.7, 0.6, and 0.7 K/W of 3 × 3, 4 × 4, and 5 × 5 LED array module, respectively. In addition, the light output power was increased of 14, 13, and 12% with 3 × 3, 4 × 4, and 5 × 5 LEDs array module using cup-shaped copper sheet at high current injection. High heat dissipation performance and light extraction were obtained by cup-shaped copper sheet with copper bulk and silver mirror.
In this study, composite electroplating technique is used to fabricate the diamond-added copper (DAC) heat spreader for UV LED applications. Thermal dissipation characteristic and optical performance are improved as the composite DAC heat spreader adoption. The low thermal resistance of 18.4 K/W with UV LED using DAC heat spreader was measured. Surface temperature of UV LED using the DAC heat spreader is 45.32◦C (at 350 mA injecting current), which is lower than those of LEDs using pure copper heat spreader (50.11oC) and only sapphire substrate (62.49◦C). The thermal diffusivity of the DAC is 0.7179 cm2/s measurement by laser flash method. Output power and power efficiency of UV LEDs are also enhanced to 71.81 mW and 4.32%, respectively, at 350 mA injection current. The optimal structure design and materials fabrication will be discussed
The In10GexSb52-xSn23Te15 films (x = 2, 5, and 9) were deposited on nature oxidized silicon wafer and glass substrate by dc magnetron sputtering. The ZnS-SiO2 films were used as protective layers. The thickness of the In10GexSb52-xSn23Te15 film is 20 nm. We have studied the crystallization kinetics, structural and optical properties of the In10GexSb52-xSn23Te15 (x = 2, 5, and 9) recording films. It is found that the crystallization temperature of the film is increased with increasing Ge content. The optical contrasts of In10GexSb52-xSn23Te15 films with x = 2~9 are all higher than 30 % at a wavelength of 405 nm, showing that the films are suitable for blue laser optical recording media application.
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