The relationship between the photometric, electric, and thermal parameters of light-emitting diodes（LEDs） is important for optimizing the LED illumination design. Indium gallium aluminium phosphide（InGaAlP）-based ...The relationship between the photometric, electric, and thermal parameters of light-emitting diodes（LEDs） is important for optimizing the LED illumination design. Indium gallium aluminium phosphide（InGaAlP）-based thin-film surface-mounted device（SMD） LEDs have attracted wide attention in research and development due to their portability and miniaturization. We report the optical characterization of InGaAlP thin-film SMD LED mounted on FR4, 2 W, and 5 W aluminum（Al） packages. The optical and thermal parameters of LED are determined at different injection currents and ambient temperatures by combining the T3ster（thermal transient tester） and TeraL ED（thermal and radiometric characterization of power LEDs） systems. Analysis shows that LED on a 5 W Al substrate package obtains the highest luminous and optical efficiency.展开更多
Fluxless soldering can solve a series of problems caused by side-effects afflux essentially. Feasibility research on vacuum fluxless laser soldering and mechanism analysis on fluxless action of vacuum were carried out...Fluxless soldering can solve a series of problems caused by side-effects afflux essentially. Feasibility research on vacuum fluxless laser soldering and mechanism analysis on fluxless action of vacuum were carried out. Fluxless soldering succeeded in spreading and wetting on Cu pad with laser heating source in vacuum surroundings. What' s more, this fluxless technology was applied in surface mounting of chip resistance successfully.展开更多
A surface mounted device （SMD） microwave ceramic band-pass filter for mobile communication with a new coupling structure is reported in this paper. In this filter, the external and internal coupling structures are f...A surface mounted device （SMD） microwave ceramic band-pass filter for mobile communication with a new coupling structure is reported in this paper. In this filter, the external and internal coupling structures are fabricated on an alumina substrate and both resonators and coupling structures are placed into a metal house to cut off its radiation. The relationship between the coupling structures and the performance of the filter is analyzed by high frequency structure software （HFSS） and the filter with a center frequency of 836.5 MHz, bandwidth of 40.0 MHz, pass-band ripple of 0.1 dB and insertion loss of 1.5 dB has been successfully designed and fabricated. The measured results show a good agreement with the simulation results.展开更多
文摘The relationship between the photometric, electric, and thermal parameters of light-emitting diodes（LEDs） is important for optimizing the LED illumination design. Indium gallium aluminium phosphide（InGaAlP）-based thin-film surface-mounted device（SMD） LEDs have attracted wide attention in research and development due to their portability and miniaturization. We report the optical characterization of InGaAlP thin-film SMD LED mounted on FR4, 2 W, and 5 W aluminum（Al） packages. The optical and thermal parameters of LED are determined at different injection currents and ambient temperatures by combining the T3ster（thermal transient tester） and TeraL ED（thermal and radiometric characterization of power LEDs） systems. Analysis shows that LED on a 5 W Al substrate package obtains the highest luminous and optical efficiency.
基金This project is subsidized by Natural Science Funds of Naion.The authorized number is 59671063.
文摘Fluxless soldering can solve a series of problems caused by side-effects afflux essentially. Feasibility research on vacuum fluxless laser soldering and mechanism analysis on fluxless action of vacuum were carried out. Fluxless soldering succeeded in spreading and wetting on Cu pad with laser heating source in vacuum surroundings. What' s more, this fluxless technology was applied in surface mounting of chip resistance successfully.
基金Supported by Sino-British Excellent Youth Scholar Foundation (2005362)the Natural Science Foundation of Hubei Province (2008CDB315)
文摘A surface mounted device （SMD） microwave ceramic band-pass filter for mobile communication with a new coupling structure is reported in this paper. In this filter, the external and internal coupling structures are fabricated on an alumina substrate and both resonators and coupling structures are placed into a metal house to cut off its radiation. The relationship between the coupling structures and the performance of the filter is analyzed by high frequency structure software （HFSS） and the filter with a center frequency of 836.5 MHz, bandwidth of 40.0 MHz, pass-band ripple of 0.1 dB and insertion loss of 1.5 dB has been successfully designed and fabricated. The measured results show a good agreement with the simulation results.
