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991.
Paul C.‐P. Chao C.‐Y. Shen C.‐W. Chiu J.‐S. Huang Y.‐Y. Kao T.‐Y. Tu C.‐L. Wang Solomon Chi H.‐W. Lin S.‐Y. Tsai 《Journal of the Society for Information Display》2008,16(2):317-327
Abstract— The objective of this study is to design a novel cone‐shaped lens cap on LEDs in order to achieve high optical efficiency in an ultra‐thin directly lit RGB LED backlight unit (BLU) for large‐sized LCD TVs. The use of the novel lens cap could play the role of a diffuser, a low light‐efficiency component in a BLU, in order to gain higher efficiency and simultaneously provide satisfactory uniformity in light distribution. The novel cone‐shaped lens is coated with aluminum on the outside surface of the cone for mirroring effects to reflect most of the LED emitted light horizontally and then reflect the light at the BLU boundaries, and then, finally to the output plane. In this way, bright spots on the output plane of the BLU can be avoided, leading to increased uniformity. Simulations were conducted to design and optimize varied aspects of the designed lens and BLU, including the cone angle of the proposed lens and the LED spacing (pitch). To further achieve color balance, a known Genetic Algorithm is used to search for the optimal angular placement of each RGB LED, resulting in better color balance. Finally, a prototype BLU for large‐sized 37‐in. LCD TVs with the proposed lens was built to verify the expected performance. 相似文献
992.
Biomimetic nanostructures like butterfly wing's scale were fabricated with an anodic aluminum oxide (AAO) nanoimprint lithography technique. This bio-inspiration nanostructure exhibits an intrinsic hydrophobic property and thus was applied as a flexible encapsulation layer in organic light-emitting diodes (OLEDs) to improve device's lifetime. A ∼80% enhancement on lifetime was obtained with simply imprinting the biomimetic nanostructures onto the flexible substrates. Our work provides a simple encapsulation approach for OLEDs, especially for flexible OLEDs. 相似文献
993.
Since organic light emitting diode (OLED) is a multilayer device where each layer has different refractive index, total internal reflection (TIR) plays an important role in limiting the efficiency of an OLED. Due to the presence of TIR, a major portion of light is trapped within the device in various wave guiding modes. Of the total light trapped in an OLED, we address only the part that is lost due to wave guiding mode arising from refractive index mismatch at the glass-air interface. Microlens array, to improve luminance, is a method that can be externally applied to the OLEDs without altering its electrical characteristics and is easy to use. Microlens arrays ranging from 10 to 40 μm have been fabricated using an organic elastomeric material polydimethylsiloxane (PDMS) by mold transfer technique. Maximum improvement of 25% in outcoupling efficiency for blue OLED is reported upon using the microlens array with diameter 10 μm. For a given diameter of microlens, out-coupling efficiency of OLED increases as height to diameter (H/D) ratio of microlens array approaches 0.5 (perfect hemisphere). It is also observed that outcoupling efficiency increases with the diameter of microlens for a given H/D ratio. The best luminescence improvement was observed for blue OLED, which can be explained by the higher refractive index of PDMS at lower wavelengths. 相似文献
994.
The linear cofactor difference operator (LCDO) method, a direct parameter extraction method for general diodes, is presented. With the developed LCDO method, the extreme spectral characteristic of the diode voltage-current curves is revealed, and its extreme positions are related to the diode characteristic parameters directly. The method is applied to diodes with different sizes and temperatures, and the related characteristic parameters, such as reverse saturation current, series resistance and non-ideality factor, are extracted directly. The extraction result shows good agreement with the experimental data. 相似文献
995.
A fast-speed pulse detector based on n-type Si-Sehottky diode mounted in the waveguide is investigated. The relation of the fast-speed pulse detector between response time and 3 dB bandwidth is analyzed. By adopting the tunable circuit, the matched bandwidth is achieved as wide as possible. Experi- mental results show that the pulse response time of the detector is less than 150 ps within random carrier signal 500 MHz bandwidth range between 35 GHz to 39 GHz via tuning circuit. The detector is very easy to operate because it does not need bias current or synch-pulse source. 相似文献
996.
Silicon carbide PIN diodes have been fabricated using a direct-write laser-doping technique that reduces defect generation
compared to the conventional ion-implantation technique. Nitrogen and aluminum were successfully incorporated into SiC as
n-type and p-type dopants, respectively. Rutherford backscattering studies were conducted to compare the lattice defect generation
by the laser-doping and ion-implantation techniques. No amorphization was observed in laser-doped samples, eliminating the
need for high-temperature annealing. The current-voltage (I-V) and capacitance-voltage (C-V) characteristics of the PIN diodes
were also investigated. The silicon carbide diodes are intended for high-temperature and high-voltage power electronics applications. 相似文献
997.
998.
文章采用石英光纤作为柱透镜,进行阵列半导体激光器的快轴准直实验研究,采用ISO推荐的光强二阶矩的方法,测量了发光面为1μm ×150μm的阵列半导体激光器准直后的光束半径、远场发散角、束腰位置、瑞利长度,并根据测量结果计算了光束传输因子(M2 因子) 。以此为基础,研制了耦合光学系统,采用直径200μm柱面透镜准直后,阵列半导体激光器快轴方向发散角可减小到0. 42°,系统准直耦合效率达到89%以上。 相似文献
999.
K. Subramanian W.P. Kang J.L. Davidson W.H. Hofmeister B.K. Choi M. Howell 《Diamond and Related Materials》2005,14(11-12):2099
We report the fabrication and field emission characteristics of the nanodiamond planar lateral field emission diode. Nanodiamond films with grain size as small as 5–10 nm have been realized through the process of CH4/H2/N2 microwave plasma enhanced chemical vapor deposition (MPECVD) by employing an effective growth rate reduction technique. Well-controlled processes have been developed; including reactive ion etch (RIE) to pattern the nanodiamond films to fabricate lateral field emission devices with planar lateral fingers. An anode–cathode spacing of 2 μm between the nanodiamond anode and cathode has been achieved. A nanodiamond lateral diode equipped with 6 fingers and an inter-electrode separation of 3 μm exhibits a turn-on voltage of 5.9 V (threshold electric field of 1.9 V/μm), one of the lowest reported for lateral field emission devices, and a high emission current of 1.1 mA ( 183 μA current per finger) at an anode voltage of 100 V ( 30 V/μm). The emission current is found to be stable with 4% fluctuation at 1 mA over 10 h. The nanodiamond lateral device is very promising for applications in vacuum nanoelectronics, sensors, and nanoelectromechanical systems. 相似文献
1000.
33 W半导体激光器列阵光纤耦合模块 总被引:3,自引:3,他引:0
利用光纤柱透镜和光束转换装置压缩半导体激光器列阵(LDA)的发散角,然后通过聚焦透镜将激光束耦合入芯径为400μm的微球透镜光纤。LDA与光纤耦合输出后,实现33W的高出纤功率,最高耦合效率大于80%,光纤的数值孔径(NA)为0.22。 相似文献