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A 16cm, ∅29.1mm compatible projection CRT, integrated component system has been developed utilizing an LD-Hi-UPF electron gun with an effective focusing lens of 21mm. This was achieved with a dual diameter neck (∅29.1-36.5mm) integrated component design. The current ∅29.1mm projection CRT deflection power was maintained while reducing the 5% center beam spot profile size by 20% (2mA optimum focus). The integrated components were optimized to provide the system with improved corner focus. This CRT delivers superior image quality and is compatible with current ∅29.1mm neck CRTs in rear projection systems.

This paper introduces a newly developed electron beam simulator for CRTs with axi-asymmetric electron guns. Effects of space charge, thermal spread, and deflection defocusing were all taken into consideration in the development process.In this simulator, the electron beam is divided into Gaussian beamlets, with each having a main trajectory and paraxial trajectories around it. For calculating the electrostatic field in the main lens, the multipole field expansion method was used together with the surface charge method to reduce CPU time and to simplify data input for complicated electrodes.The simulator was used to investigate dynamic astigmatism correction using a quadrupole lens in the main lens, and the cancellation of an astigmatism using slits and square apertures in the beam-forming region. Calculations of the beam spot diameters closely matched the actual measurements (differences were 10% at most). This test confirmed the simulator's effectiveness in investigating and designing CRT axi-asymmetric electron guns.

In order to reduce the raster moire fringes appearing in high-resolution CRTs, an evaluation technique is developed which simulates visual appearances of the moire patterns by using a Gaussian weighting method. It has been found that the moire patterns are strongly influenced by the shape of an electron beam profile. By using the evaluation technique, optimum electron beam profiles for various moire modes are pursued. Although the common belief is that the Gaussian current density distribution is the best for the beam profile which gives least moire fringes, it is found that an introduction of a small deviation to the Gaussian distribution reduces the moire contrast to an appreciable extent. This enables us to design CRT electron guns which have an improved moire characteristic.

CRT is the most successful electron optical system, commercially. Over a hundred million systems are produced each year, and distributed to the whole world as television sets or personal computers. Therefore, the system has to be extremely cost and power effective, and ergonomics is the important issue at its design. Also, CRT has to be bright enough to be watched in the luminous living or office room. Therefore, electron beam current and anode voltage (CRT screen voltage) are as high as 0.5 to 7 mA and 20 to 33 kV, respectively. These unique restrictions cause unique electron lens design such as in-line rotationally asymmetrical lens or dynamic quadrupole lens and deflection yoke design such as self converging deflection yoke which produces barrel shaped vertical and pin-cushion shaped horizontal magnetic fields. In this paper the recent technical advancement and future trends of the CRT electron optical system will be discussed. The discussion will be restricted only to the picture tube, and other devices such as camera tube, oscilloscope tube will be excluded.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

— An evaluation technique of overall raster moire patterns on color CRTs is developed. The technique can simulate any of the moire modes. Generation mechanisms of various moire patterns are clarified using the technique. It is found that the moire patterns, no matter how complicated, consist of four basic types: barrel, pincushion, elliptical, and hyperbolic types. The patterns are found to be sensitive to the scan line distribution. When the scan lines are curved, the pattern appearing on the upper screen is different from that on the lower screen. When the scan lines are tilted, the patterns have horizontal shifts. By observing the moire patterns, the scan line distribution can be estimated precisely.

Generation mechanisms of various moire patterns are clarified, and a simulation technique of overall raster moire patterns appearing on the color CRT screen is developed. The moire patterns are found to be sensitive to the slope and curvature of the scan lines. The technique allows to determine various CRT design parameters.

— A simulator for electron beams of CRTs with axi-asymmetric electron guns was developed, taking into account space-charge effects, thermal spreads of electrons, and deflection-defocusing effects. In the simulator, the electron beam is divided into Gaussian beamlets, each having a main trajectory and paraxial trajectories surrounding it. For the calculation of the electrostatic field in the main lens, the multipole field-expansion method was used in combination with the surface-charge method to reduce CPU time and simplify data input for complicated electrodes. The dynamic astigmatism correction, accomplished by placing a quadrupole lens in the main lens, and the cancellation of astigmatism by using slits and square apertures in the beam-forming region were investigated. Calculated beam-spot diameters agreed well with measurements (differences were at most about 10%). The simulator was confirmed to be effective for investigating and designing axi-asymmetric electron guns for CRTs.