Color filter-less technology of LED back light for LCD-TV - art. no. 68410G

Back Light Unit (BLU) and Color Filter are the two key components for the perfect color display of Liquid Crystal Display (LCD) device. LCD can not light actively itself, so a form of illumination, Back Light Unit is needed for its display. The color filter which consists of RGB primary colors, is used to generate three basic colors for LCD display. Traditional CCFL back light source has several disadvantages, while LED back light technology makes LCD obtain quite higher display quality than the CCFL back light. LCD device based on LED back light owns promoted efficiency of display. Moreover it can generate color gamut above 100% of the NTSC specification. Especially, we put forward an idea of Color Filter-Less technology that we design a film which is patterned of red and green emitting phosphors, then make it be excited by a blue light LED panel we fabricate, for its special emitting mechanism, this film can emit RGB basic color, therefore replace the color filter of LCD device. This frame typically benefits for lighting uniformity and provide pretty high light utilization ratio. Also simplifies back light structure thus cut down the expenses.

Ultra-compact silicon-on-insulator optical filter based on sidewall Bragg grating

Micro-cavity structure composed of silicon wire with 240nm square cross section and two symmetrical sidewall waveguide Bragg gratings is fabricated and studied for the operation under telecommunication wavelengths. Optical filter of quasi-TE mode was realized based on this cavity. In such micro-cavity, optical quality factor (Q) was measured up to 380 with a 4.8nm free spectral range (FSR) and 12dB fringe contrast (FC). The measured group index of silicon waveguide with only 240nm square cross section was between 3.80 and 5.43. It is the first time group delay of silicon wire waveguide with such small core dimension is studied. Larger group delay can be expected after optimizing the design parameters and the fabrication process.

Design of Low Power Multi-Standard Active-RC Filter for WLAN and DVB-H

In this paper, a low-power, highly linear, integrated, active-RC filter exhibiting a multi-standard (IEEE 802.11a/b/g and DVB-H) application and bandwidth (3MHz, 4MHz, 9.5MHz) is present. The filter exploits digitally-controlled polysilicon resister banks and an accurate automatic tuning scheme to account for process and temperature variations. The automatic frequency calibration scheme provides better than 3% corner frequency accuracy. The Butterworth filter is design for receiver (WLAN and DVB-H mode) and transmitter (WLAN mode). The filter dissipation is 3.4 mA in RX mode and 2.3 mA (only for one path) in TX mode from 2.85-V supply. The dissipation of calibration consumes 2mA. The circuit has been fabricated in a 0.35um 47-GHz SiGe BiCMOS technology, the receiver and transmitter occupy 0.28-mm(2) and 0.16-mm(2) (calibration circuit excluded), respectively.

Simulation and fabrication of the SiC-based clamped-clamped filter

In this paper, the SiC-based clamped-clamped filter was designed and fabricated. The filter was composed of two clamped-clamped beam micromechanical resonators coupled by a spring coupling beam. Structural geometries, including the length and width of the resonator beam and coupling beam, were optimized by simulation for high frequency and high Q, under the material properties of SiC. The vibrating modes for the designed filter structure were analyzed by finite element analysis (FEA) method. For the optimized structure, the geometries of resonator beams and coupling beams, as well as the coupling position, the SiC-based clamped-clamped filter was fabricated by surface micromaching technology.

Design and Fabrication of a Photonic Crystal Channel Drop Filter Based on an Asymmetric Silicon-on-Insulator Slab

We report on the design and fabrication of a photonic crystal (PC) channel drop filter based on an asymmetric silicon-on-insulator (SOI) slab. The filter is composed of two symmetric stick-shape micro-cavities between two single-line-defect (W1) waveguides in a triangular lattice, and the phase matching condition for the filter to improve the drop efficiency is satisfied by modifying the positions and radii of the air holes around the micro-cavities. A sample is then fabricated by using electron beam lithography (EBL) and inductively coupled plasma (ICP) etching processes. The measured 0 factor of the filter is about 1140, and the drop efficiency is estimated to be 73% +/- 5% by fitting the transmission spectrum.

High-Q and High-extinction-ratio Microdisk Add-drop Filter with Grating Couplers in Silicon-on-Insulator

Submitted by 阎军 (yanj@red.semi.ac.cn) on 2010-06-04T08:08:51Z No. of bitstreams: 1 High-Q and High-extinction-ratio Microdisk Add-drop Filter with Grating Couplers in Silicon-on-Insulator.pdf: 662474 bytes, checksum: dbdd3fba410c875bd74a6d4823930a44 (MD5)

复杂背景条件下红外弱小目标检测技术研究

红外弱小目标检测技术是红外搜索与跟踪、红外预警、红外制导等防御和武器系统中的一项核心技术。研究复杂背景条件下的红外弱小目标检测技术，有利于提高红外探测系统的探测灵敏度，对增大系统作用距离、增加反应时间、提高己方的生存概率具有重要的意义。 本文针对复杂背景下的红外弱小目标检测技术进行了三个方面的研究: 1、 从红外成像系统方面对红外焦平面阵列的非均匀性校正问题进行研究。本文结合红外焦平面阵列的非线性模型(“S”形曲线模型)和Kalman滤波器，提出一种新的基于Kalman滤波的改进型两点校正法，该算法具有“S”形曲线两点校正法的处理简单、计算精度高等特点，同时利用Kalman滤波器对校正参数进行估计和修正，解决了“参数漂移”问题。实验仿真的结果表明，该算法能较好的对红外焦平面阵列进行非均匀校正。 2、 本文从红外图像预处理方面对红外背景抑制技术进行研究。针对传统的背景抑制算法难以解决的杂波干扰问题，本文提出了一种基于局部统计信息变化的自适应杂波抑制算法AFBLS（Adaptive Filter Based on Local Statistic），该算法能够对目标进行灰度增强，同时对杂波进行抑制。AFBLS算法结合传统的背景抑制算法，可以有效的对红外背景和杂波干扰进行抑制。对红外图像进行实验仿真的结论是：AFBLS杂波抑制算法是一种较好的红外弱小目标图像预处理方法，它能有效提高已有背景抑制算法的性能。 3、 本文对红外弱小目标检测算法进行了研究。分析了经典的管道算法的不足之处，并在此基础上对其进行改进，提出了动态更新的管道检测算法。通过仿真实验我们验证了改进的管道算法的性能，实验结果表明，该算法能够有效的对信噪比SNR（Signal-to-Noise Ratio）大于2的序列图像进行目标检测。

Ultra-narrow dual-channel filter based on symmetrical sampled fibre Bragg grating

A kind of ultra-narrow dual-channel filter is proposed in principle and demonstrated experimentally. This filter is designed by means of two sampled fibre Bragg gratings (SFBGs), where one is periodic 0-pi sampling and the other is symmetrical spatial sampling. The former can create two stopbands in the transmission spectra and the latter can produce two ultra-riarrow passbands. Our filter has the 3-dB bandwidth of about 1 pm, whose value is two orders of magnitude less than the bandwidth of the traditional SFBG filters. The proposed filter has a merit that the channel spacing remains unchanged when tuning the filter.

Magnetic barrier on strained graphene: A possible valley filter

We put forward a two-terminal valley filter based on a bulk graphene sheet under the modulations of both a local perpendicular magnetic field and a substrate strain. When only one of the two modulations is present, no valley polarization can be generated. A combination of the two modulations leads to a different (but not opposite) shifts of the K and K' valleys, which could be utilized to generate a valley-polarized current. The degree of the valley polarization can be tuned by the strain strength and the inclusion of a scalar potential. The valley polarization changes its polarity as the local magnetic field switches its direction.

A multi-standard active-RC filter with accurate tuning system

A low-power, highly linear, multi-standard, active-RC filter with an accurate and novel tuning architec-ture is presented. It exhibits 1EEE 802. 11a/b/g (9.5 MHz) and DVB-H (3 MHz, 4 MHz) application. The filter exploits digitally-controlled polysilicon resistor banks and a phase lock loop type automatic tuning system. The novel and complex automatic frequency calibration scheme provides better than 4 comer frequency accuracy, and it can be powered down after calibration to save power and avoid digital signal interference. The filter achieves OIP3 of 26 dBm and the measured group delay variation of the receiver filter is 50 ns (WLAN mode). Its dissipation is 3.4 mA in RX mode and 2.3 mA (only for one path) in TX mode from a 2.85 V supply. The dissipation of calibration consumes 2 mA. The circuit has been fabricated in a 0.35μm 47 GHz SiGe BiCMOS technology; the receiver and transmitter filter occupy 0.21 mm~2 and 0.11 mm~2 (calibration circuit excluded), respectively.