动态聚焦技术及动态聚焦电子枪

截至目前，动态聚焦技术是改进大屏幕、大偏转角显像管边角分辨率和高清晰度彩色显示管分辨率均匀性的最有效方法。本文介绍与讨论了在荧光屏边缘处电子束点畸变原因以及几种典型动态聚焦电子枪的结构与性能。     

A new high-performance color picture tube: The mask-focusing color tube

From a technical point of view, improvements of conventional color picture tubes could be regarded as having reached their limits. In this respect, we have found that the mask-focusing tube can achieve further improvements when combined with the black-matrix technique, a high-performance gun, dot screen structure, high-matrix transparency, and large gun electrode diameter. Two-fold improvements of brightness and contrast have been obtained with mask transparency twice that of conventional tubes, 22-percent higher matrix transparency, and mask-focusing. A 20-30 percent less deflection power has also been achieved with 110° deflection, neck diameter, and 1:2 mask-focusing voltage ratio. A 20-percent less spot diameter and a sharp beam distribution have been obtained by a new multistage-focusing electron gun in a delta arrangement in the 35.5-mm neck diameter.     

Electron images of vidicon cathodes

Excessive patchiness of the emission from the oxide-coated cathodes used in cathode-ray tubes, camera tubes and traveling-wave tubes can have adverse effects on their performance or useful life. There is a simple technique for forming an electron image of a CRT cathode directly on the view screen. This technique, which has been known for more than 30 years, may be used to show patchiness when it exists, but it has not been possible in the past to image the cathode of a camera tube because of the lack of a built-in display mechanism (phosphor-coated view screen) and because of the peculiar geometry of the electron guns. A technique has now been devised for displaying the electron images of vidicon cathodes. This technique comprises) 1) priming the optical image-sensing surface with uniform light, 2) projecting a "pinhole snapshot" electron image of the cathode on the image-sensing surface with an unscanned beam and storing it there, and 3) reading out the stored image with the normal scanning beam and displaying it on a CRT monitor. Photographs of electron images of vidicon cathodes obtained in this manner are shown in this paper.     

Astigmatic electron gun for the beam-indexing color television display

Though the beam-indexing color television display has some obvious advantages when compared with other display systems, the electron-optical demands are very high. First, these demands and the imaging system to be used are discussed. It turns out that the beam must be astigmatic to obtain optimum performance. The beam shape is prescribed by the deflection-coil design. This beam shape, giving rise to a vertically elongated spot of sufficiently small dimensions, is obtained by using an astigmatic gun of special design in combination with a simple rotation-symmetrical focusing lens. After a general discussion of the focusing properties of this combination, the intensity distributions along both the minor and the major axis of the spot on the screen are calculated and compared with experiments. The gamma of the beam current characteristic is measured as well as calculated. Its dependence on the beam current is small up to beam currents of about 3 mA. Moreover, the cathode loading is calculated as a function of the beam current. Without special means of dynamic correction, satisfactory color reproduction in normal picture material is obtained up to peak currents of 1.5 mA in 110°-25 in tubes. Higher beam currents would be attainable in the absence of a residual deflection error which causes a tilt of the spot near the corners of the screen. The structure of the picture is quite acceptable at a triplet pitch of 1.2 mm without using a lenticular screen.     

微型彩色显示管校正透镜的设计与加工技术

曝光透镜是彩管曝光台中的一个光学零件，它主要用于彩色CRT荧光屏制造过程中模拟电子束进行光学曝学涂屏。就是要使电子束都能一一对应地落在由光线曝光所制出的荧光粉点上，以得到满屏正确的色纯。     

A technique for aging the phosphor of high-resolution cathode-ray tubes with particular application to P-16

An accelerated aging technique--restricted to P-16 phosphor--that measures a cathode-ray tube screen degradation with use is described. A small area of the screen is aged at high excitation densities and the light output from this area is plotted as a function of deposited charge per unit area. A pre-aged part of the screen is used as a reference level for measuring these light output levels. Measurements made to determine phosphor aging with cathode-ray tube operating modes are described. Aging is found invariant with spot focus, beam voltage, beam current, power density per unit area, and sweep speed over normal operating ranges. Deposited charge per unit area is confirmed as the dominant stress factor. Under restricted operating conditions, the data is reproducible within ±4 percent at the 95 percent confidence level. Aging rates accelerated by a factor of more than a thousand as compared to normal usage have been obtained.     

偏转对电子束上屏束径的影响

彩色显像管中，电子束经偏转系统偏转后在屏的边角处的尺寸比中心部分尺寸大。为了解决偏转散焦，日本松下公司推出了ＤＡＦ枪。然而随着ＨＤＴＶ的发展，电子束束流和偏转角都越来越大，此时仅靠调节动态聚焦电压不能完全补偿过聚焦以及大束流下空间电荷效应的影响。本文研究了大束流、大偏转角情况下造成偏转散焦的原因，提出在调节动态聚焦电压的同时适当改变电子束进入主聚焦透镜的入射角，从而改善电子束经偏转后的上屏质量。     

A high-resolution electron gun for thermoplastic recording using prefocus deflection

A demagnification gun of high resolution was developed for thermoplastic recording by deflecting the electron beam at the entry of a large focusing lens. The unconventional approach of prefocus deflection allows close spacing between the "short" focusing lens and the target (phosphor screen or thermoplastic tape) required for demagnification and results in a gun with a relatively short length. The diameter of the focusing lens is about three times larger than the 25-mm diameter area to be scanned in order to keep spot distortions of the deflected beam at a minimum. Electrostatic focusing combined with magnetic deflection was selected. The special focusing lens that is used is shaped for low aberrations, increased demagnification and increased deflection sensitivity. Small deflection fields are required since the electron beam is being deflected in the accelerating field while the electron velocities are still low. The gun operates at 10 kv and delivers a 5-micron spot at 1µa. This corresponds to a resolution of 5000 spot diameters at average current densities in excess of 5 amp/cm². In spite of the high resolution, the over-all length of the gun measured from the target is only 9 inches.     

Influence of space charge on the Langmuir limit for focused electron beams

A theoretical investigation of the validity of Langmuir's expression for the limiting current density in a focused electron beam when space-charge forces are significant was carried out by computing the performance of a series of simple electron tubes, each consisting of a Pierce gun coupled by a thin lens to an equipotential drift space. The analyses show that, while the cathode current density and the peak current density in the spot are related, they are not directly proportional as stated in Langmuir's expression which, therefore, does not give an accurate prediction of the current density that can be obtained in the spot. The dimensions of the tubes were chosen such that this conclusion is also valid in the case of television picture tubes. It is also shown that thermal velocities have only a minor influence on the lens strengths required to focus beams, and that the focused spots havea Gaussian distribution of current density even though the emission density in a Pierce gun is uniform.     

Writing speed and tonal range of dark trace tubes

The writing speed and tonal range properties of dark trace tubes are analyzed and figures of merit are outlined. Experimental results are presented. Writing speed of a dark trace tube varies linearly with the ratio of beam current to spot size. The information writing rate varies directly with the beam current and inversely with the square of the spot size. The tonal range of dark trace tubes varies directly with the ratio of maximum contrast to spot size.     

A cyclotron-wave rectifier for S-band and X-band

A device for converting microwave power into either dc power or low-frequency ac power has been investigated both theoretically and experimentally. Rotational energy is stored in an electron beam by a Cuccia coupler, then converted to longitudinal energy by interaction with a space-dependent dc magnetic field, and finally recovered as electric energy by a depressed collector. A simple kinematic analysis demonstrates that the Cuccia coupler can convert large amounts of microwave power into electron beam rotation. Limits on the electric field strength and asynchronism between signal frequency and cyclotron frequency are established for both classical and relativistic coupler operation. Efficiency analyses of the process of conversion from orbital energy to dc electric energy, both classical and relativistic, indicate that the efficiency exceeds 95 percent for a particular range of operating conditions. As an ac power supply, the device responds to the modulating frequency of the signal. Theory predicts near-negligible harmonic distortion as well as flatness of frequency response from dc to about 1.0 MHz modulating frequency. Four tubes and a prototype (with "artificial" coupler) were tested experimentally. The first three tubes exhibited efficiencies up to 22 percent, being hindered by reflection of electrons into the coupler. Certain design changes were tested on the prototype, where efficiencies from 36 percent to 75 percent were obtained. Incorporating these design changes into the fourth tube yielded measured efficiencies up to 34 percent, or when corrected to disregard unusually large cavity losses, up to 59 percent. Experimental tests of the tube as an ac converter yielded excellent frequency response and about 20 percent second-harmonic distortion. It is concluded that the theoretical foundation of efficiency predictions has thus far been based on too optimistic assumptions.     

Small-size 81- to 83.5-percent efficient 2- and 4-stage depressed collectors for octave-bandwidth high-performance TWT's

In a joint USAF-NASA Program, Lewis Research Center is carrying out an efficiency improvement program on traveling wave tubes (TWT) for use in electronic counter measures (ECM) by applying multistage depressed collector (MDC) and spent beam refocusing techniques developed at Lewis. In the analytic part of the effort, three-dimensional electron trajectories are computed throughout the TWT. Trajectory computation continues through the spent beam refocuser and the depressed collector. Collector efficiency, collector losses, and overall efficiency are identified and computed. On the experimental side, tube performance is evaluated first without the MDC; then, the spent beam is analyzed for symmetry, circularity, and velocity spread. Finally, the MDC is attached and its performance optimized and evaluated. The three-dimensional theory, for ideal tubes, predicts a MDC-efficiency, at mid-band, of 81 percent for a 2-stage MDC with symmetric, circular, and optimally refocused beams and 85.5 percent for a 4-stage MDC. Experimental results to date have yielded MDC efficiencies of a minimum of 81 and 83 percent for a 2- and 4-stage MDC, respectively, across a one-octave bandwidth of a 4.8 to 9.6 GHz 330-to-550-W TWT.     

荫罩式彩显管电子束斑测量技术的研究

本文提出了实时地,真实地再现荫罩式彩显管电子束斑的原理和方法;描述了系统的硬件组成;微偏转系统的要求和设计原则;     

管材激光弯曲成形有限元工艺仿真及其机理研究

管材激光弯曲成形是一种柔性金属塑性成形方法,将连续的激光光斑简化为一间歇跳跃的方形面热源,并且考虑材料性能参数与温度的相关性,建立了管材激光弯曲成形的热-机耦合有限元工艺仿真模型。有限元仿真结果表明:同板料的激光弯曲成形一样,对应于加热和冷却阶段,管材的激光弯曲成形也分别经历反向弯曲和正向弯曲两个变形阶段,管材激光弯曲成形的内在机理是典型的温度梯度机理。     

The utilization of positive ions for investigations of stray field effects in electrostatic lenses

The paper describes a method for the investigation of stray fields caused by surface charges on the glass supports of cathode-ray-tube guns. These stray fields may penetrate into the gap of an unshielded electrostatic lens and contribute to the astigmatic distortions of the entire electron optical system. The focused spot on the screen of the tube then shows deviations from the ideal circular shape. The investigation of the stray field influences was carried out utilizing the positive ion component of the electron beam. Discoloration patterns on the second grid aperture due to ion bombardment indicated the expected distortion of the focused spot. Various gun designs were tested in this manner.     

基于Spindt冷阴极的行波管电子枪设计

针对X波段小型化Spindt冷阴极螺旋线行波管进行了电子枪设计.基于皮尔斯型电子枪结构,联合PPM高频聚焦系统,以电子注聚焦特性为优化目标,采用CST粒子工作室对电子枪结构和工作参数进行了优化设计,获得了 30 mA工作电流下电子注填充比为0.68的良好电子注聚焦.在此电子枪结构和高频结构下,分析了特定电流下电子注聚焦...     

A cyclotron resonance frequency multiplier

The current density available from known thermionic cathodes imposes a serious limitation on the power output obtainable from electron tubes operating at frequencies above about 10 Gc. This paper describes a proposal for a frequency multiplier which has the interesting property that the RF energy imparted to the electron beam by the signal source may be one or two orders of magnitude greater than the dc energy supplied by the battery. Thus it is expected that the power output at a particular frequency will be much higher for a given cathode current density than that obtained from conventional types of electron-beam oscillators and amplifiers. The multiplier operates by converting the input energy at one radio frequency into rotational energy of an electron beam by means of a Cuccia coupler. The beam then couples power to the output load via a multicavity circuit containing2ncavities wherenis the frequency multiplication to be obtained. The paper includes details of experimental work on a low-power tube multiplying from 600 Mc to 3600 Mc. In this tube 1.3 watts of RF input power is coupled on to a 50 volt, 260-µa beam and the power at 3600 Mc is coupled out via a 12-cavity magnetron anode structure. Photographs are given of the trace of the rotating beam impinging on a fluorescent screen and these demonstrate the degree of focussing achieved along the length of the tube. The paper concludes with a study of the feasibility of a tube multiplying from 10 Gc to 100 Gc with an output of tens of watts.     

DESIGN AND PERFORMANCE OF SHAPING DEFLECTORS FOR VARIABLY SHAPED ELECTRON BEAM LITHOGRAPHY

In order to obtain uniform exposure in variably shaped electron beam lithography,the beam current density and edge resolution on the target must not change for different spotshapes and sizes.The key to the goal is the appropriate design of shaping deflectors.A linearand rotation compensation approach is presented.Values of linear and rotation compensationfactors versus the distances between electron source image and centers of deflectors are measuredon an experimental electron beam column with variable spot shaping.The experimental resultsare in good agreement with the calculated ones.     

变形电子束曝光机成形偏转器的设计和性能

在变形电子束曝光机中,为使曝光均匀必须保证靶上束斑电流密度物边缘分辨率不随束斑形状和尺寸的变化而改变。实现这一目标的关键是正确设计成形偏转器。本文讨论采用高灵敏度平行板偏转器实现成形偏转时,为达到上述目标应进行的线性补偿和旋转补偿的设计计算方法。给出了用实验方法改变电子源象与偏转板几何中心的轴向距离所测得的线性补偿因子和旋转补偿因子的值。实验结果与计算值符合较好。