两种新型无源OLED显示列驱动电路的研究与设计

针对两种采用不同灰度调制方式和预充方法的新型无源OLED显示列驱动电路进行研究和设计。阐述了脉冲宽度调制和脉冲幅度调制两种灰度显示方式的一致性,提出相对应两种灰度调制方式的列驱动电路,从电路设计到版图实现上比较了这两种电路。阐述了电压和电流两种预充方式,设计出两种新型预充方法,并且应用到OLED显示驱动芯片中。Hspice仿真和版图实现后表明,两种列驱动电路中前者的版图面积约是后者的1/2,采用省电模式预充方法的后者的功耗约是前者的1/3。     

基于OLED灰度显示的新方法

介绍了有机发光二极管(OLED)技术特点、彩色实现方式和驱动方式.针对OLED灰度显示,介绍了实现灰度显示的两种常用方法即脉宽调制和帧灰度调制,并分析了各自的特点.在此基础上,尝试了一种新的方法,将二者结合起来共同实现灰度显示.这种方法不仅可以保持脉宽调制灰度显示的高速度,还可以保持帧灰度方式的均匀、稳定和足够的响应速度,而且可以大大提高灰度级别数.介绍了利用这种新方法实现OLED灰度显示数据的具体方式,该方法在硬件实现上简单易行,节约面积成本.     

改进型PWM灰度调制技术在FED中的应用研究

根据FED显示器响应特性,设计了改进型PWM灰度调制方法.通过确定驱动脉冲顺序,结合人眼的视觉特性设计了最优PWM调制技术.通过调整驱动脉冲增量,实现了单位时间亮暗转换次数最大化和亮暗转换频率均匀化的优化目标.采用FPGA控制技术实现了改进型PWM灰度调制,减少了FED图像灰阶损失,提高了图像显示质量.     

碳纳米管场致发射显示灰度调制方式的研究

碳纳米管的一个重要的应用是在场发射显示器件中作为电子的发射体。本文主要探讨了幅度调制、空间调制、时间调制等几种平板显示中常见的灰度等级实现方式以及其各自的优缺点，尤其针对碳纳米管场致发射显示（CNT-FED）中发射体的缺陷和功耗等问题进行了深入研究。脉宽调制（PWM，Pulse Width Modulation）能够一定程度上保护碳纳米管，降低碳纳米管显示器的功耗，而且实现简单。最后本文给出PWM方式实现CNT—FED的灰度显示的实验方案和在碳纳米管显示器样机上的显示效果图。     

基于数字微反射镜与光源复合编码的高帧频显示方法

作为常用显示器件,数字微镜器件(DMD)使用传统的脉冲宽度调制(PWM)显示方法受最小脉冲宽度限制,无法满足高帧频显示的需求。文章提出基于光源与DMD复合编码的高帧频显示技术,利用光源调制解决脉冲宽度调制导致的位平面显示时间随位平面等级指数增长的问题。通过构建包含驱动模块、光源和DMD的显示系统,采用低4位光源脉冲宽度调制与高4位DMD显示时间宽度调制相结合的方法,将8位灰度图像的显示帧频提高至2 461 Hz。     

基于FPGA的FED显示器PWM灰度调制电路研制

介绍了场致显示器的灰度调制的原理及其灰度调制驱动电路的设计。采用FPGA控制技术实现前端视频信号接口、脉宽灰度调制的功能。通过串并转换模块与寻址芯片的连接，将PWM信号放大驱动FED显示屏实现视频图像的显示。该电路能驱动63．5cm彩色FED样机实现256级灰度显示。     

基于DMD的高动态图像超高帧频显示方法

数字微镜器件(DMD)在用于高帧频探测系统的功能和性能测试时,必须保证DMD能够超高帧频显示图像,而传统的脉冲宽度调制(PWM)方法的显示帧频受限于DMD加载数据所需的最短耗时,无法满足实际需求.为了解决这一问题,驱动DMD超高帧频显示高动态范围的图像,在结合DMD硬件特性和传统PWM理论的基础上,利用图像叠加背景光显示技术,提出了一种改进的脉冲宽度调制DMD实现灰度图像显示的方法.适用于8位灰度以上的高动态范围图像的DMD超高帧频显示,实验表明,该方法将8位灰度图像的DMD显示帧频提高到1 kHz.     

Four-Level Pulse Width Modulation for Fiber Optic Communications

The performance of a digital fiber optical system employing four-level pulse width modulation (PWM) is considered. It is shown that PWM may be an attractive alternative to pulse amplitude modulation (PAM), especially if a wide band channel is used. The probability density function (pdf) of the timing error is obtained in terms of the pdf of the noise amplitude, taking into account the thermal noise of the amplifier and the signal-dependent shot noise introduced by the photodiode detector. Near-Gaussian optical pulse edges at the receiver are assumed. Using typical system parameters, the variation of bit error rate (BER) with power level, and the effects of different bit rates, mean photodetector gain, and system bandwidths are calculated. It is observed that minimum BER's are achieved at moderate values of mean photodetector gain and that increased system bandwidth results in increased receiver sensitivity.     

新型CNT-FED驱动电路的研究

碳纳米管已经作为电子源广泛应用于场致发射显示器件中。本文讨论了场致发射显示器的工作特性．以及CNTFED对驱动电路的要求。根据脉宽调制（PWM，Pulse Width Modulation）额基本原理，本文提出了新型的灰度实现方式。该方法灰度等级实现方法简单，大大降低了扫描信号的频率要求。     

Novel TFT-Based emission driver in high performance AMOLED display applications

A novel integrated row driver for emission control with n-type thin-film transistors (TFTs) was proposed. A single stage of the proposed driving circuit consists of charge supplement unit, improved inverter, and power conservation unit besides input TFT and driving TFTs. Simulations were carried out with fabricated LTPS TFT. The results show the driving circuit achieves leakage prevention with no floating state and high reliability even under the V_th shift of 3 V. What's more, further measurement results show a 3 μs pulse width can be generated by the circuit, supporting 8k4k resolution with high refresh rate of 120 Hz. And the capability of low refresh rate (1 Hz) driving also can be achieved without degradation. In addition, only three control signals (two non-overlap clocks and one input signal) are used in the proposed circuit, where input signal of present stage is connected with the output of its previous stage. That means the row driver can work under independent control and be not susceptible, which contributes to generating adjustable pulse width for pulse width modulation (PWM) in active matrix organic light-emitting diode (AMOLED) displays.     

基于双重调制技术的可见光通信系统研究

LED调制带宽制约着可见光通信(VLC) 系统的数据传输速率。为此,提出一种基于双重调制技术COB(chip on board)封装 的LED灯具,通过实现16级脉冲振幅 调制(PAM),将系统数据传输速率提升4倍;结合脉冲宽度调制(PWM)技术 进行调光,同时兼顾室内的照明及通信。采用Matlab软件模拟仿真视频传输试 验。结果表明,在相同信噪比(SNR)的情况下,基于双重 调制技术的VLC系统的误码率(BER)比传统使用开关键控(OOK)调控技术系 统的BER更低。本文系统在不增加器件带宽前提下,成倍提高了无线通信的 质量与 数据传输速率;从照明与通信的角度优化了VLC系统的信源,具有广阔的 应用前景。     

Simple analytical and graphical methods for carrier-based PWM-VSIdrives

This paper provides analytical and graphical methods for the study, performance evaluation and design of the modern carrier-based pulse width modulators (PWMs), which are widely employed in PWM voltage-source inverter (VSI) drives. Simple techniques for generating the modulation waves of the high-performance PWM methods are described. The two most important modulator characteristics-the current ripple and the switching losses-are analytically modeled. The graphical illustration of these often complex multivariable functions accelerate the learning process and help one understand the microscopic (per-carrier cycle) and macroscopic (per fundamental cycle) behavior of all the modern PWM methods. The analytical formulae and graphics are valuable educational tools. They also aid the design and implementation of the high-performance PWM methods     

激光半主动寻的制导激光编码的研究

通过理论分析,指出可用于激光半主动寻的制导的激光编码方式主要有脉冲间隔调制（PIM）和脉冲宽度调制（PWM）。通过分析和研究现有的国内外许多激光编码及其特点,提出了一种PIM编码与PWM编码混编的新型编码思想,并给出了具体的编码方法。最后给出了激光编码的发展趋势。     

反射式液晶器件振幅调制特性的研究

研究了反射式液晶器件(RLCOS)的振幅调制特性.采用2×2的琼斯矩阵计算仿真,从理论上分析了它的振幅调制特性.实验采用He Ne激光为光源,将反射式液晶器件显示器作为液晶空间光调制器,用计算机和相关的电路系统驱动控制,并用CCD采样数据,测试了1024×768反射式液晶器件显示器的振幅调制特性.与未改形光束剖面相比,在特定的入射、出射偏振光配制下,可以用反射式液晶器件显示器来做振幅调制器.     

An Experimental Comparison Between Direct and Indirect PAM by a High-Efficiency Microwave Frequency Multiplier with Varactor Diodes (Correspondence)

Two pulse amplitude modulation (PAM) methods by a high-efficiency frequency multiplier with varactor diodes are compared. Typical results achieved for an X-band to Q-band tripler prove that the direct PAM is better than the indirect one under the same conditions. The former acts as a pulse shaper (PS), and has an output rise time smaller than the rise time of the output voltage of the modulator chain.     

Gate-Last MoS2 Transistors for Active-Matrix Display Driving Circuits

Advancements in display technology have primarily focused on discovering new materials to develop thin-film transistors (TFTs) that complement mainstream technologies. The emerging 2D semiconductors are one of the most promising candidates due to their ultra-thin thickness, exceptional electrical qualities, and large-scale availability. However, these atomically thin materials are delicate and typically prepared through standard gate-first fabrication processes, necessitating their transfer onto specific substrates. In this study, a demonstration of an in situ gate-last process for 2D semiconductor-based TFTs technology is presented. This approach bypasses the yield-limiting transfer process, enabling large-scale display applications. The as-fabricated MoS₂ TFTs retains their intrinsic properties with a current density reaching ≈≈10 µA µm⁻¹. Additionally, it is successfully showcased that the two transistor-one capacitor active-matrix display driving circuits with a high pixel yield. The patterned matrix exhibits no crosstalk and can be driven by either the pulse amplitude modulation or pulse width modulation scheme, offering flexible applications.     

一种改善LED显示屏亮度均匀性的算法

基于显示屏控制技术与校正原理,提出了一种改善LED显示屏亮度均匀性的算法.通过CCD相机采集显示屏RGB图像,用数学形态学和模板匹配法确定灯点的位置并根据发光区域的灰度值计算其相对亮度,生成每个灯点的校正参数,用脉冲宽度调制控制灯点的亮度.实验结果表明提出的算法能有效改善显示屏的亮度均匀性,提高显示屏的显示质量并延长其使用寿命.     

A PWM signal processing core circuit based on a switched currentintegration technique

A highly functional circuit for pulse width modulation (PWM) signal processing is proposed as a core of the A-D merged circuit architecture for time-domain information processing. The core circuit employs a switched-current integration technique as its computing architecture and functions as a linear arithmetic operator, a memory, and also a delaying device of PWM signals. A 0.8-μm CMOS test chip includes 110 transistors plus two capacitors and performs parallel additions and multiplications at the accuracy of 1.2 ns. A cumulative property of the technique allows the circuit to serve as a low-power accumulator that consumes 23% of the energy of the full digital 7-b accumulator. A PWM multiply-accumulate unit and a nonlinear operation unit are also proposed to extend functionality of the circuit. Since the PWM signal carries multibit data in a binary amplitude pulse, these circuits can be favorably applicable to low-voltage and low-power designs in the deep submicrometer era     

用于激光打标机的首脉冲自动抑制技术

声光Q开关作为调Q器件用于激光腔内,在脉冲工作方式下,首个脉冲激光的能量相当大,会造成声光器件损毁或激光打标的标记过深。传统的首脉冲抑制需调制信号和外控信号2个外部输入信号,用户在使用过程中感觉操作较繁琐且易出错。该文介绍了一种自动抑制首脉冲强度的方法。首脉冲自动抑制技术是通过单片机(MCU)与可编程逻辑阵列门电路(CPLD)自动改变前几个脉冲的宽度,达到自动抑制前几个光脉冲强度的目的。     

一种用于CATV系统的光纤脉冲宽度调制多路传输方案

本文对脉冲宽度的调制、解调方法和其频谱进行了分析,提出了一种在CATV系统中用于直接传输射频电视信号的多路复用系统方案,并通过对其优点的论述和与其它几种模拟调制方式的比较,认为PWM调制技术在传输多路模拟信号方面是非常有吸引力和潜在应用能力的,它在未来将有广泛的用途。