共查询到19条相似文献,搜索用时 203 毫秒
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真空荧光显示管激发功率分布的均匀性分析 总被引:1,自引:1,他引:0
平板荧光显示管采用直丝阴极的结构方式使电子激发阳极荧光粉的功率分布不均匀,举例计算,在空间电荷限制区,头尾单元的激发功率相差3倍以上,正对阴极丝的地方与阳极上下沿的激发功率相差约3倍。制管中尺寸公差和工艺技术也会影响激发功率分布。调整栅阴极距离和采用适当工作电路可改善功率分布的均匀性;在结构条件允许时,采用校正电路可消除其不均匀性;较高的亮度水平可减轻或消除人眼对亮度不均匀性的视觉感受。 相似文献
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一四一二所十一室课题组 《真空电子技术》1983,(2)
氧化物阴极是人们很熟悉的一种热电子发射体。一般认为这种阴极是靠阴极基金属中的杂质元素(即通常所说的激活剂)在热的作用下扩散到氧化物涂层中,使氧化钡还原成钡原子而得到良好的热电子发射电流。这种阴极的发射电流不仅受阴极基金属本身及基金属中杂质的影响,而且与杂质在阴极基金属中的扩散状态关系也密切。本文所介绍的用锆铝(Zr-Al)合金作激活剂的阴极与普通氧化物阴极不同,它所用的锆铝合金激活剂不是加在阴极基金属中,而是直接加在氧化物涂层中。这样,激活剂就直接与 相似文献
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我公司在开发显示管的过程中 ,将原用于显像管的铆接式阴极用于显示管时发现 :显示管的短期特性很差 ,即在开机初期亮度跌落严重 ,如图 1所示 ,工作电流为 50 μA时 ,开机 3分钟与开机 2 0秒相比亮度可跌落 30 %以上。如此大的亮度衰减 ,用户无法接受 ,为此我们借鉴国外先进技术 ,自行开发了悬吊式阴极 ,使亮度衰减由 30 %以上降到 1 0 %以下 ,极大地改善了显示管的短期特性 ,完全满足了用户的要求 ,填补了国内的空白。本文仅就悬吊阴极是如何改善显示管短期特性的原理进行了简单地分析。图 1 不同型阴极的初期特性 (实测 )1 同样的阴极… 相似文献
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本文描述一种高收敛皮尔斯枪,其电子注层流性能基本上与无栅枪相似,而工作比超过三极管型有截获的栅控电子枪。因为四极管型电子枪是在栅丝之间100%的发射表面上较为均匀地支取电流,所以单位面积上的阴极负载远小于一般的阴影栅电子枪或栅极贴近阴极的阴影栅电子枪。理论研究和电子注分析器研究以及 IJ 波段大功率螺旋线行波管的热测都已证实,若微调四极管型电子枪的两个控制栅电压,将使性能有大幅度地改进。可调的栅丝透镜可使电子注直径和层流最佳,并反映了公差的变化。在管子包装组件内还包括一个简单的自偏压网络,以便用普通的栅极脉冲调制器工作。 相似文献
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本文提出一种新型的具有阴极栅和阳极栅的部分薄膜SOI LIGBT。正向导通状态下,当负压加在阳极栅上时,器件具有低导通电阻。在阻断状态下,阴极栅和阳极栅分别短接在发射极和收集极,导致高开关速度。而且,漂移区以下部分硅衬底的刻蚀避免在埋氧层下界面聚集电荷,这使得电势线可以释放到薄膜以下,因而产生高击穿电压。再有,无衬底-漏极电容使器件具有高开关速度。最后,漂移区横向均匀和线形掺杂相结合的浓度分布不仅提高了耐压,而且降低了导通电阻。与常规LIGBT相比,提出的新结构展示了高电流容量,高开关速度,低导通电阻和2倍的击穿电压。 相似文献
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丝网印刷三极CNT-FEA的研制 总被引:1,自引:0,他引:1
制作三极型场发射阵列(FEA),传统上都依赖薄膜工艺及光刻技术.这在很大程度上限制了印刷型碳纳米管阴极的优势.通过改进全丝网印刷工艺,包括一项改进的栅极烧结工艺和一项洁网技术,成功地制作出,32×32的三极型以碳纳米管为阴极的场发射阵列(CNT-FEA).该三极型CNT-FEA具有显著的栅控特性.栅压在150~300 V可以对阳极电流实现良好的控制.栅控电流放大系数超过180. 相似文献
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[现象] 10kW调频发射机开机一段时间后,末前级突然过荷跳闸,保护指示灯亮。[分析与检查] 末前级跳闸且不能恢复,说明3kV有二次过荷现象。检查末前级,加上灯丝电压和偏压后,栅流表和阴流表即有指示,且指针反向偏转。图1是末前级功放的简化电路图。从图1分析,加上灯丝电压和偏压后电表有指示,说明栅-阴极已构成通路,在栅偏压的作用下,栅流表和阴流表有电流流过,电流方向如图1所示,电流I =EgR1 R2 Rg Rk Rgk图1 末前级功放简化图式中Rg 和Rk 分别为栅流表和阴流表内阻,Rgk为栅-阴极间的输入电阻。因为灯丝电源电压Uf 是平衡输入的,对… 相似文献
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本文根据大功率电子管工作时阴极变形的机理分析,讨论了减小阴极变形的人为控制办法,可以大大延长电子管的使用寿命。 相似文献
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《Electron Devices, IEEE Transactions on》1979,26(10):1438-1443
A hydrogen thyratron capable of switching 40 kV and 40 kA in repetitive bursts at the 1-MW average power level is described. Major design problems were obtaining the necessary forward and inverse holdoff capability and controlling the thermal and mechanical effects of the several kilowatts of operating dissipation encountered at this power level. A conventional external anode, planar-electrode, ceramic-metal tube design was chosen to meet the design requirements, which include reliable, kickout-free operation following long periods of standby. Emission was provided by a large cathode specifically designed to handle ohmic heating due to the 1500 A of rms-equivalent pulse current, as well as the heat developed in the surrounding plasma. Massive auxiliary, control, and gradient grids were incorporated into a tightly baffled box-type grid structure of sufficient total aperture area to prevent quenching below 70-80 kA. Molybdenum wall shielding was employed to improve holdoff capability and prevent arc damage. Design and operating considerations are discussed and representative test results for the first 16 tubes are given, together with the results of special tests for high peak current, high average current, and high-voltage holdoff. 相似文献
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采用COMSOL有限元分析软件的固体传热模块,对有机电致发光器件(OLED)的热学特性进行了仿真,发现器件温度随着输入功率成线性增大。在驱动电流为150 mAcm-2时,仿真结果表明,Alq3发光层的最高温度为82.994 3℃;玻璃基板下表面的最高温是77.392 6℃;器件阴极表面中心区域的最高温度为82.994 2℃,其平均温度为78.445℃。通过改变功能层热传导率、功能层厚度、对流换热系数、表面发射率等参数模拟其对OLED器件热学特性的影响,结果表明,当增加基板的热传导率时,OLED器件温度显著下降而且表面及内部温度梯度大幅减小;提高空气对流换热系数及基板的表面发射率,OLED的温度可以大幅减小。而其他参数则对其影响并不明显。 相似文献
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WANG Hong-yi LAI Xin-quan LI Yu-shan 《半导体光子学与技术》2007,47(1):1-6
A novel design of multiplex differential voltage comparators(MDVC) is presented for reducing current and power dissipation. According to the special properties of relational operation and logical operation, parts of the comparators are redundant in some instances, and thus can be turned off. By selecting and switching the current routes, several effective differential pairs are biased by a single tail current stage-by-stage and the redundant comparators are turned off by cutting their tail currents. As a result, the quiescent current and power consumption are greatly decreased. The switching of current is achieved by the input differential pair transistors themselves and hence no extra switches are required. When a MDVC is used in a flash analogto-digital converter(ADC), its current dissipation is much lower than that of the conventional comparators. This architecture can also be used in window-comparators, maximum or minimum comparators, and comparators for logical operations. The power dissipation in all these cases could be reduced significantly. 相似文献
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本文介绍了一种摄象管阴栅系统的传热计算模型,对5种不同结构、不同功率的阴栅系统进行了电子计算机计算。通过计算得出了各处的温度、各相关部件间的热交换情况和系统的总耗散功率以及各参量对它们的影响。这些对设计阴栅系统有一定的指导意义。文中还给出了一种低功率(0.6W)钡镍阴极阴栅系统的设计。它具有牢固可靠、易于装配、速热(数秒可达工作温度)等优点。 相似文献
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S.-S. Kwak 《International Journal of Electronics》2013,100(12):1683-1693
Light emitting diodes (LEDs) have been gradually used for backlight modules for liquid crystal display as a substitute for cold cathode fluorescent lamps. In most of LED applications, it is required to connect several LED strings in parallel to limit the dc voltage level to be applied to the single LED string. Due to considerable current variations through each LED string with inevitable parameter deviations as well as temperature and ageing effects, techniques to balance currents flowing through LED strings are required for LED drivers. This article proposes a pulse-driven LED circuit with transformer-based current balancing scheme, which can simply regulate currents through the LED strings. The transformers are placed in series with the LED strings in such a way that the LED currents are automatically balanced. Since the developed current sharing technique employs no dissipative resistors and no linear-mode transistors, the proposed driver has high efficiency, low power dissipation and reduced thermal problems. In addition, the presented driver with no additional semiconductor devices and no additional controllers can provide a simple and a cost-effective current balancing solution, compared to conventional approaches. Thus, the proposed LED driver can feature a simple, highly efficient, reliable and cost-effective method. The presented LED driver is verified with experimental results. 相似文献